* [PATCH v7 0/3] Add SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
This series add support the SSIF BMC driver which is to perform in-band
IPMI communication with their host in management (BMC) side.
SSIF BMC driver in this series is tested with Aspeed AST2500.
Discussion for v6: https://lkml.org/lkml/2022/3/10/340
v7:
+ Remove unnecessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ Correct the patches order to fix the bisect issue found by
kernel build robot
v4:
+ Fix recursive spinlock [Graeme]
+ Send response with Completion code 0xFF when aborting [Quan]
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, don't
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
+ Added slave_enable() to struct i2c_algorithm to control
slave mode and to address the recursive spinlock [Graeme, Ryan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Switched binding doc to use DT schema format [Rob]
+ Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Remove mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
+ Combine mask/unmask two interrupts together [Corey]
+ Fixed unhandled Tx done with NAK [Quan]
+ Late ack'ed Tx done w/wo Ack irq [Quan]
+ Use aspeed-specific exported aspeed_set_slave_busy() when
slave busy to fix the deadlock [Graeme, Philipp, Quan]
+ Clean buffer for last multipart read [Quan]
+ Handle unknown incoming command [Quan]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
Quan Nguyen (3):
ipmi: ssif_bmc: Add SSIF BMC driver
bindings: ipmi: Add binding for SSIF BMC driver
i2c: aspeed: Assert NAK when slave is busy
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++
drivers/i2c/busses/i2c-aspeed.c | 5 +-
6 files changed, 941 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
--
2.35.1
^ permalink raw reply [flat|nested] 67+ messages in thread
* [PATCH v7 0/3] Add SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
This series add support the SSIF BMC driver which is to perform in-band
IPMI communication with their host in management (BMC) side.
SSIF BMC driver in this series is tested with Aspeed AST2500.
Discussion for v6: https://lkml.org/lkml/2022/3/10/340
v7:
+ Remove unnecessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ Correct the patches order to fix the bisect issue found by
kernel build robot
v4:
+ Fix recursive spinlock [Graeme]
+ Send response with Completion code 0xFF when aborting [Quan]
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, don't
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
+ Added slave_enable() to struct i2c_algorithm to control
slave mode and to address the recursive spinlock [Graeme, Ryan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Switched binding doc to use DT schema format [Rob]
+ Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Remove mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
+ Combine mask/unmask two interrupts together [Corey]
+ Fixed unhandled Tx done with NAK [Quan]
+ Late ack'ed Tx done w/wo Ack irq [Quan]
+ Use aspeed-specific exported aspeed_set_slave_busy() when
slave busy to fix the deadlock [Graeme, Philipp, Quan]
+ Clean buffer for last multipart read [Quan]
+ Handle unknown incoming command [Quan]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
Quan Nguyen (3):
ipmi: ssif_bmc: Add SSIF BMC driver
bindings: ipmi: Add binding for SSIF BMC driver
i2c: aspeed: Assert NAK when slave is busy
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++
drivers/i2c/busses/i2c-aspeed.c | 5 +-
6 files changed, 941 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
--
2.35.1
^ permalink raw reply [flat|nested] 67+ messages in thread
* [PATCH v7 0/3] Add SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
This series add support the SSIF BMC driver which is to perform in-band
IPMI communication with their host in management (BMC) side.
SSIF BMC driver in this series is tested with Aspeed AST2500.
Discussion for v6: https://lkml.org/lkml/2022/3/10/340
v7:
+ Remove unnecessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ Correct the patches order to fix the bisect issue found by
kernel build robot
v4:
+ Fix recursive spinlock [Graeme]
+ Send response with Completion code 0xFF when aborting [Quan]
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, don't
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
+ Added slave_enable() to struct i2c_algorithm to control
slave mode and to address the recursive spinlock [Graeme, Ryan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Switched binding doc to use DT schema format [Rob]
+ Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Remove mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
+ Combine mask/unmask two interrupts together [Corey]
+ Fixed unhandled Tx done with NAK [Quan]
+ Late ack'ed Tx done w/wo Ack irq [Quan]
+ Use aspeed-specific exported aspeed_set_slave_busy() when
slave busy to fix the deadlock [Graeme, Philipp, Quan]
+ Clean buffer for last multipart read [Quan]
+ Handle unknown incoming command [Quan]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
Quan Nguyen (3):
ipmi: ssif_bmc: Add SSIF BMC driver
bindings: ipmi: Add binding for SSIF BMC driver
i2c: aspeed: Assert NAK when slave is busy
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++
drivers/i2c/busses/i2c-aspeed.c | 5 +-
6 files changed, 941 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:08 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
in-band IPMI communication with their host in management (BMC) side.
Thanks Dan for the copy_from_user() fix in the link below.
Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Remove unneccessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ None
v4:
+ Send response with Completion code 0xFF when aborting [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, dont
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Removed mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++++
4 files changed, 899 insertions(+)
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index b061e6b513ed..18a89093d64e 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
found on Aspeed SOCs (AST2400 and AST2500). The driver
implements the BMC side of the BT interface.
+config SSIF_IPMI_BMC
+ tristate "SSIF IPMI BMC driver"
+ select I2C
+ select I2C_SLAVE
+ help
+ This enables the IPMI SMBus system interface (SSIF) at the
+ management (BMC) side.
+
+ The driver implements the BMC side of the SMBus system
+ interface (SSIF).
+
config IPMB_DEVICE_INTERFACE
tristate 'IPMB Interface handler'
depends on I2C
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 7ce790efad92..cb6138b8ded9 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
+obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
new file mode 100644
index 000000000000..4cff5e1a075e
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.c
@@ -0,0 +1,780 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+
+#include "ssif_bmc.h"
+
+static const char *state_to_string(enum ssif_state state)
+{
+ switch (state) {
+ case SSIF_READY:
+ return "SSIF_READY";
+ case SSIF_START:
+ return "SSIF_START";
+ case SSIF_SMBUS_CMD:
+ return "SSIF_SMBUS_CMD";
+ case SSIF_REQ_RECVING:
+ return "SSIF_REQ_RECVING";
+ case SSIF_RES_SENDING:
+ return "SSIF_RES_SENDING";
+ case SSIF_ABORTING:
+ return "SSIF_ABORTING";
+ default:
+ return "SSIF_STATE_UNKNOWN";
+ }
+}
+
+/* Handle SSIF message that will be sent to user */
+static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (!ssif_bmc->request_available) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ ssif_bmc->request_available);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ ret = -EINVAL;
+ } else {
+ count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
+ memcpy(&msg, &ssif_bmc->request, count);
+ ssif_bmc->request_available = false;
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ ret = copy_to_user(buf, &msg, count);
+ }
+
+ return (ret < 0) ? ret : count;
+}
+
+/* Handle SSIF message that is written by user */
+static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ if (count > sizeof(struct ssif_msg))
+ return -EINVAL;
+
+ if (copy_from_user(&msg, buf, count))
+ return -EFAULT;
+
+ if (!msg.len || count < msg.len + 1)
+ return -EINVAL;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (ssif_bmc->response_in_progress) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ !ssif_bmc->response_in_progress);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ /*
+ * The write must complete before the response timeout fired, otherwise
+ * the response is aborted and wait for next request
+ * Return -EINVAL if the response is aborted
+ */
+ ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
+ if (ret)
+ goto exit;
+
+ del_timer(&ssif_bmc->response_timer);
+ ssif_bmc->response_timer_inited = false;
+
+ memcpy(&ssif_bmc->response, &msg, count);
+ ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
+
+ ssif_bmc->response_in_progress = true;
+
+ /* ssif_bmc not busy */
+ ssif_bmc->busy = false;
+
+ /* Clean old request buffer */
+ memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
+exit:
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return (ret < 0) ? ret : count;
+}
+
+static int ssif_bmc_open(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ int ret = 0;
+
+ spin_lock_irq(&ssif_bmc->lock);
+ if (!ssif_bmc->running)
+ ssif_bmc->running = 1;
+ else
+ ret = -EBUSY;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return ret;
+}
+
+static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ __poll_t mask = 0;
+
+ poll_wait(file, &ssif_bmc->wait_queue, wait);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ /* The request is available, userspace application can get the request */
+ if (ssif_bmc->request_available)
+ mask |= POLLIN;
+
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return mask;
+}
+
+static int ssif_bmc_release(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ ssif_bmc->running = 0;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return 0;
+}
+
+/*
+ * System calls to device interface for user apps
+ */
+static const struct file_operations ssif_bmc_fops = {
+ .owner = THIS_MODULE,
+ .open = ssif_bmc_open,
+ .read = ssif_bmc_read,
+ .write = ssif_bmc_write,
+ .release = ssif_bmc_release,
+ .poll = ssif_bmc_poll,
+};
+
+/* Called with ssif_bmc->lock held. */
+static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* Invalidate response in buffer to denote it having been sent. */
+ ssif_bmc->response.len = 0;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->remain_len = 0;
+ ssif_bmc->busy = false;
+ memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
+ wake_up_all(&ssif_bmc->wait_queue);
+}
+
+static void response_timeout(struct timer_list *t)
+{
+ struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ /* Do nothing if the response is in progress */
+ if (!ssif_bmc->response_in_progress) {
+ /* Recover ssif_bmc from busy */
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+ /* Set aborting flag */
+ ssif_bmc->aborting = true;
+ }
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+}
+
+/* Called with ssif_bmc->lock held. */
+static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* set ssif_bmc to busy waiting for response */
+ ssif_bmc->busy = true;
+ /* Request message is available to process */
+ ssif_bmc->request_available = true;
+ /* Clean old response buffer */
+ memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
+ /* This is the new READ request.*/
+ wake_up_all(&ssif_bmc->wait_queue);
+
+ /* Armed timer to recover slave from busy state in case of no response */
+ if (!ssif_bmc->response_timer_inited) {
+ timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
+ ssif_bmc->response_timer_inited = true;
+ }
+ mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
+}
+
+static void calculate_response_part_pec(struct ssif_part_buffer *part)
+{
+ u8 addr = part->address;
+
+ /* PEC - Start Read Address */
+ part->pec = i2c_smbus_pec(0, &addr, 1);
+ /* PEC - SSIF Command */
+ part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
+ /* PEC - Restart Write Address */
+ addr = addr | 0x01;
+ part->pec = i2c_smbus_pec(part->pec, &addr, 1);
+ part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
+ if (part->length)
+ part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
+}
+
+static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ part->length = ssif_bmc->response.len;
+
+ /* Clear the rest to 0 */
+ memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
+ memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
+}
+
+static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ u8 part_len = 0;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_MULTIPART_READ_START:
+ /*
+ * Read Start length is 32 bytes.
+ * Read Start transfer first 30 bytes of IPMI response
+ * and 2 special code 0x00, 0x01.
+ */
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->block_num = 0;
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
+ ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
+
+ part->payload[0] = 0x00; /* Start Flag */
+ part->payload[1] = 0x01; /* Start Flag */
+
+ memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
+ break;
+
+ case SSIF_IPMI_MULTIPART_READ_MIDDLE:
+ /*
+ * IPMI READ Middle or READ End messages can carry up to 31 bytes
+ * IPMI data plus block number byte.
+ */
+ if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
+ /*
+ * This is READ End message
+ * Return length is the remaining response data length
+ * plus block number
+ * Block number 0xFF is to indicate this is last message
+ *
+ */
+ /* Clean the buffer */
+ memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
+ part->length = ssif_bmc->remain_len + 1;
+ part_len = ssif_bmc->remain_len;
+ ssif_bmc->block_num = 0xFF;
+ part->payload[0] = ssif_bmc->block_num;
+ } else {
+ /*
+ * This is READ Middle message
+ * Response length is the maximum SMBUS transfer length
+ * Block number byte is incremented
+ * Return length is maximum SMBUS transfer length
+ */
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
+ part->payload[0] = ssif_bmc->block_num;
+ ssif_bmc->block_num++;
+ }
+
+ ssif_bmc->remain_len -= part_len;
+ memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
+ part_len);
+ break;
+
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+
+ ssif_bmc->nbytes_processed += part_len;
+}
+
+static bool supported_read_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_READ ||
+ cmd == SSIF_IPMI_MULTIPART_READ_START ||
+ cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
+ return true;
+
+ return false;
+}
+
+static bool supported_write_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ return true;
+
+ return false;
+}
+
+/* Process the IPMI response that will be read by master */
+static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ /* msg_idx start from 0 */
+ if (part->index < part->length)
+ *val = part->payload[part->index];
+ else if (part->index == part->length && ssif_bmc->pec_support)
+ *val = part->pec;
+ else
+ *val = 0;
+
+ part->index++;
+}
+
+static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* msg_idx should not be 0 when reach here */
+ if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
+ return;
+
+ if (ssif_bmc->msg_idx == 1) {
+ ssif_bmc->part_buf.length = *val;
+ ssif_bmc->part_buf.index = 0;
+ } else {
+ ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
+ }
+
+ ssif_bmc->msg_idx++;
+}
+
+static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ bool ret = true;
+ u8 cpec;
+ u8 addr;
+
+ if (part->index == part->length) {
+ /* PEC is not included */
+ ssif_bmc->pec_support = false;
+ ret = true;
+ goto exit;
+ }
+
+ if (part->index != part->length + 1) {
+ ret = false;
+ goto exit;
+ }
+
+ /* PEC is included */
+ ssif_bmc->pec_support = true;
+ part->pec = part->payload[part->length];
+ addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ cpec = i2c_smbus_pec(0, &addr, 1);
+ cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
+ cpec = i2c_smbus_pec(cpec, &part->length, 1);
+ /*
+ * As SMBus specification does not allow the length
+ * (byte count) in the Write-Block protocol to be zero.
+ * Therefore, it is illegal to have the last Middle
+ * transaction in the sequence carry 32-byte and have
+ * a length of ‘0’ in the End transaction.
+ * But some users may try to use this way and we should
+ * prevent ssif_bmc driver broken in this case.
+ */
+ if (part->length)
+ cpec = i2c_smbus_pec(cpec, part->payload, part->length);
+
+ if (cpec != part->pec)
+ ret = false;
+
+exit:
+ return ret;
+}
+
+static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_SINGLEPART_WRITE:
+ /* save the whole part to request*/
+ ssif_bmc->request.len = part->length;
+ memcpy(ssif_bmc->request.payload, part->payload, part->length);
+
+ break;
+ case SSIF_IPMI_MULTIPART_WRITE_START:
+ ssif_bmc->request.len = 0;
+
+ fallthrough;
+ case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
+ case SSIF_IPMI_MULTIPART_WRITE_END:
+ /* Do the bound check here, not allow the request len exceed 254 bytes */
+ if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
+ memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
+ part->payload, part->length);
+ ssif_bmc->request.len += part->length;
+ } else {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: Request exceeded 254 bytes, aborting");
+ /* Request too long, aborting */
+ ssif_bmc->aborting = true;
+ }
+ break;
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+}
+
+static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* SMBUS command can vary (single or multi-part) */
+ ssif_bmc->part_buf.smbus_cmd = *val;
+ ssif_bmc->msg_idx = 1;
+
+ if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
+ /*
+ * The response maybe not come in-time, causing host SSIF driver
+ * to timeout and resend a new request. In such case check for
+ * pending response and clear it
+ */
+ if (ssif_bmc->response_in_progress)
+ complete_response(ssif_bmc);
+
+ /* This is new request, flip aborting flag if set */
+ if (ssif_bmc->aborting)
+ ssif_bmc->aborting = false;
+ }
+}
+
+static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ REQUESTED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_RES_SENDING;
+ }
+
+ ssif_bmc->msg_idx = 0;
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ if (ssif_bmc->is_singlepart_read)
+ set_singlepart_response_buffer(ssif_bmc);
+ else
+ set_multipart_response_buffer(ssif_bmc);
+
+ calculate_response_part_pec(&ssif_bmc->part_buf);
+ ssif_bmc->part_buf.index = 0;
+ *val = ssif_bmc->part_buf.length;
+}
+
+static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_SMBUS_CMD) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ PROCESSED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+ }
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ handle_read_processed(ssif_bmc, val);
+}
+
+static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
+ ssif_bmc->state = SSIF_START;
+
+ } else if (ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE REQUEST in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ return;
+ }
+
+ ssif_bmc->msg_idx = 0;
+ ssif_bmc->part_buf.address = *val;
+}
+
+static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+
+ } else if (ssif_bmc->state == SSIF_START) {
+ ssif_bmc->state = SSIF_SMBUS_CMD;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_REQ_RECVING;
+ }
+
+ /* This is response sending state */
+ if (ssif_bmc->state == SSIF_REQ_RECVING)
+ handle_write_received(ssif_bmc, val);
+ else if (ssif_bmc->state == SSIF_SMBUS_CMD)
+ process_smbus_cmd(ssif_bmc, val);
+}
+
+static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_SMBUS_CMD ||
+ ssif_bmc->state == SSIF_ABORTING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected SLAVE STOP in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_READY;
+
+ } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
+ if (validate_request_part(ssif_bmc)) {
+ process_request_part(ssif_bmc);
+ if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ handle_request(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ } else {
+ /*
+ * A BMC that receives an invalid request drop the data for the write
+ * transaction and any further transactions (read or write) until
+ * the next valid read or write Start transaction is received
+ */
+ dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
+ ssif_bmc->aborting = true;
+ }
+ } else if (ssif_bmc->state == SSIF_RES_SENDING) {
+ if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
+ /* Invalidate response buffer to denote it is sent */
+ complete_response(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ }
+
+ /* Reset message index */
+ ssif_bmc->msg_idx = 0;
+}
+
+/*
+ * Callback function to handle I2C slave events
+ */
+static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
+{
+ unsigned long flags;
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+ int ret = 0;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ switch (event) {
+ case I2C_SLAVE_READ_REQUESTED:
+ on_read_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_REQUESTED:
+ on_write_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_READ_PROCESSED:
+ on_read_processed_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_RECEIVED:
+ on_write_received_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_STOP:
+ on_stop_event(ssif_bmc, val);
+ break;
+
+ default:
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
+ break;
+ }
+
+ if (!ssif_bmc->aborting && ssif_bmc->busy)
+ ret = -EBUSY;
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return ret;
+}
+
+static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct ssif_bmc_ctx *ssif_bmc;
+ int ret;
+
+ ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
+ if (!ssif_bmc)
+ return -ENOMEM;
+
+ spin_lock_init(&ssif_bmc->lock);
+
+ init_waitqueue_head(&ssif_bmc->wait_queue);
+ ssif_bmc->request_available = false;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+
+ /* Register misc device interface */
+ ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
+ ssif_bmc->miscdev.name = DEVICE_NAME;
+ ssif_bmc->miscdev.fops = &ssif_bmc_fops;
+ ssif_bmc->miscdev.parent = &client->dev;
+ ret = misc_register(&ssif_bmc->miscdev);
+ if (ret)
+ goto out;
+
+ ssif_bmc->client = client;
+ ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
+
+ /* Register I2C slave */
+ i2c_set_clientdata(client, ssif_bmc);
+ ret = i2c_slave_register(client, ssif_bmc_cb);
+ if (ret) {
+ misc_deregister(&ssif_bmc->miscdev);
+ goto out;
+ }
+
+ return 0;
+out:
+ devm_kfree(&client->dev, ssif_bmc);
+ return ret;
+}
+
+static int ssif_bmc_remove(struct i2c_client *client)
+{
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+
+ i2c_slave_unregister(client);
+ misc_deregister(&ssif_bmc->miscdev);
+
+ return 0;
+}
+
+static const struct of_device_id ssif_bmc_match[] = {
+ { .compatible = "ssif-bmc" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ssif_bmc_match);
+
+static const struct i2c_device_id ssif_bmc_id[] = {
+ { DEVICE_NAME, 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
+
+static struct i2c_driver ssif_bmc_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = ssif_bmc_match,
+ },
+ .probe = ssif_bmc_probe,
+ .remove = ssif_bmc_remove,
+ .id_table = ssif_bmc_id,
+};
+
+module_i2c_driver(ssif_bmc_driver);
+
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
new file mode 100644
index 000000000000..2c3fc2a4698f
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+#ifndef __SSIF_BMC_H__
+#define __SSIF_BMC_H__
+
+#define DEVICE_NAME "ipmi-ssif-host"
+
+#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
+
+/* A standard SMBus Transaction is limited to 32 data bytes */
+#define MAX_PAYLOAD_PER_TRANSACTION 32
+/* Transaction includes the address, the command, the length and the PEC byte */
+#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
+
+#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
+#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
+
+#define SSIF_IPMI_SINGLEPART_WRITE 0x2
+#define SSIF_IPMI_SINGLEPART_READ 0x3
+#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
+#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
+#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
+#define SSIF_IPMI_MULTIPART_READ_START 0x3
+#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
+
+/* Include netfn and cmd field */
+#define MSG_PAYLOAD_LEN_MAX 254
+/*
+ * IPMI 2.0 Spec, section 12.7 SSIF Timing,
+ * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
+ * Recover ssif_bmc from busy state if it takes up to 500ms
+ */
+#define RESPONSE_TIMEOUT 500 /* ms */
+
+struct ssif_msg {
+ u8 len;
+ u8 payload[MSG_PAYLOAD_LEN_MAX];
+} __packed;
+
+struct ssif_part_buffer {
+ u8 address;
+ u8 smbus_cmd;
+ u8 length;
+ u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
+ u8 pec;
+ u8 index;
+} __packed;
+
+/*
+ * SSIF internal states:
+ * SSIF_READY 0x00 : Ready state
+ * SSIF_START 0x01 : Start smbus transaction
+ * SSIF_SMBUS_CMD 0x02 : Received SMBus command
+ * SSIF_REQ_RECVING 0x03 : Receiving request
+ * SSIF_RES_SENDING 0x04 : Sending response
+ * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
+ */
+enum ssif_state {
+ SSIF_READY,
+ SSIF_START,
+ SSIF_SMBUS_CMD,
+ SSIF_REQ_RECVING,
+ SSIF_RES_SENDING,
+ SSIF_ABORTING,
+ SSIF_STATE_MAX
+};
+
+struct ssif_bmc_ctx {
+ struct i2c_client *client;
+ struct miscdevice miscdev;
+ int msg_idx;
+ bool pec_support;
+ /* ssif bmc spinlock */
+ spinlock_t lock;
+ wait_queue_head_t wait_queue;
+ u8 running;
+ enum ssif_state state;
+ /* Timeout waiting for response */
+ struct timer_list response_timer;
+ bool response_timer_inited;
+ /* Flag to identify a Multi-part Read Transaction */
+ bool is_singlepart_read;
+ u8 nbytes_processed;
+ u8 remain_len;
+ u8 recv_len;
+ /* Block Number of a Multi-part Read Transaction */
+ u8 block_num;
+ bool request_available;
+ bool response_in_progress;
+ bool busy;
+ bool aborting;
+ /* Buffer for SSIF Transaction part*/
+ struct ssif_part_buffer part_buf;
+ struct ssif_msg response;
+ struct ssif_msg request;
+};
+
+static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
+{
+ return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
+}
+#endif /* __SSIF_BMC_H__ */
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
in-band IPMI communication with their host in management (BMC) side.
Thanks Dan for the copy_from_user() fix in the link below.
Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Remove unneccessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ None
v4:
+ Send response with Completion code 0xFF when aborting [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, dont
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Removed mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++++
4 files changed, 899 insertions(+)
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index b061e6b513ed..18a89093d64e 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
found on Aspeed SOCs (AST2400 and AST2500). The driver
implements the BMC side of the BT interface.
+config SSIF_IPMI_BMC
+ tristate "SSIF IPMI BMC driver"
+ select I2C
+ select I2C_SLAVE
+ help
+ This enables the IPMI SMBus system interface (SSIF) at the
+ management (BMC) side.
+
+ The driver implements the BMC side of the SMBus system
+ interface (SSIF).
+
config IPMB_DEVICE_INTERFACE
tristate 'IPMB Interface handler'
depends on I2C
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 7ce790efad92..cb6138b8ded9 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
+obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
new file mode 100644
index 000000000000..4cff5e1a075e
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.c
@@ -0,0 +1,780 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+
+#include "ssif_bmc.h"
+
+static const char *state_to_string(enum ssif_state state)
+{
+ switch (state) {
+ case SSIF_READY:
+ return "SSIF_READY";
+ case SSIF_START:
+ return "SSIF_START";
+ case SSIF_SMBUS_CMD:
+ return "SSIF_SMBUS_CMD";
+ case SSIF_REQ_RECVING:
+ return "SSIF_REQ_RECVING";
+ case SSIF_RES_SENDING:
+ return "SSIF_RES_SENDING";
+ case SSIF_ABORTING:
+ return "SSIF_ABORTING";
+ default:
+ return "SSIF_STATE_UNKNOWN";
+ }
+}
+
+/* Handle SSIF message that will be sent to user */
+static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (!ssif_bmc->request_available) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ ssif_bmc->request_available);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ ret = -EINVAL;
+ } else {
+ count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
+ memcpy(&msg, &ssif_bmc->request, count);
+ ssif_bmc->request_available = false;
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ ret = copy_to_user(buf, &msg, count);
+ }
+
+ return (ret < 0) ? ret : count;
+}
+
+/* Handle SSIF message that is written by user */
+static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ if (count > sizeof(struct ssif_msg))
+ return -EINVAL;
+
+ if (copy_from_user(&msg, buf, count))
+ return -EFAULT;
+
+ if (!msg.len || count < msg.len + 1)
+ return -EINVAL;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (ssif_bmc->response_in_progress) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ !ssif_bmc->response_in_progress);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ /*
+ * The write must complete before the response timeout fired, otherwise
+ * the response is aborted and wait for next request
+ * Return -EINVAL if the response is aborted
+ */
+ ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
+ if (ret)
+ goto exit;
+
+ del_timer(&ssif_bmc->response_timer);
+ ssif_bmc->response_timer_inited = false;
+
+ memcpy(&ssif_bmc->response, &msg, count);
+ ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
+
+ ssif_bmc->response_in_progress = true;
+
+ /* ssif_bmc not busy */
+ ssif_bmc->busy = false;
+
+ /* Clean old request buffer */
+ memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
+exit:
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return (ret < 0) ? ret : count;
+}
+
+static int ssif_bmc_open(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ int ret = 0;
+
+ spin_lock_irq(&ssif_bmc->lock);
+ if (!ssif_bmc->running)
+ ssif_bmc->running = 1;
+ else
+ ret = -EBUSY;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return ret;
+}
+
+static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ __poll_t mask = 0;
+
+ poll_wait(file, &ssif_bmc->wait_queue, wait);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ /* The request is available, userspace application can get the request */
+ if (ssif_bmc->request_available)
+ mask |= POLLIN;
+
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return mask;
+}
+
+static int ssif_bmc_release(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ ssif_bmc->running = 0;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return 0;
+}
+
+/*
+ * System calls to device interface for user apps
+ */
+static const struct file_operations ssif_bmc_fops = {
+ .owner = THIS_MODULE,
+ .open = ssif_bmc_open,
+ .read = ssif_bmc_read,
+ .write = ssif_bmc_write,
+ .release = ssif_bmc_release,
+ .poll = ssif_bmc_poll,
+};
+
+/* Called with ssif_bmc->lock held. */
+static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* Invalidate response in buffer to denote it having been sent. */
+ ssif_bmc->response.len = 0;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->remain_len = 0;
+ ssif_bmc->busy = false;
+ memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
+ wake_up_all(&ssif_bmc->wait_queue);
+}
+
+static void response_timeout(struct timer_list *t)
+{
+ struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ /* Do nothing if the response is in progress */
+ if (!ssif_bmc->response_in_progress) {
+ /* Recover ssif_bmc from busy */
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+ /* Set aborting flag */
+ ssif_bmc->aborting = true;
+ }
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+}
+
+/* Called with ssif_bmc->lock held. */
+static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* set ssif_bmc to busy waiting for response */
+ ssif_bmc->busy = true;
+ /* Request message is available to process */
+ ssif_bmc->request_available = true;
+ /* Clean old response buffer */
+ memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
+ /* This is the new READ request.*/
+ wake_up_all(&ssif_bmc->wait_queue);
+
+ /* Armed timer to recover slave from busy state in case of no response */
+ if (!ssif_bmc->response_timer_inited) {
+ timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
+ ssif_bmc->response_timer_inited = true;
+ }
+ mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
+}
+
+static void calculate_response_part_pec(struct ssif_part_buffer *part)
+{
+ u8 addr = part->address;
+
+ /* PEC - Start Read Address */
+ part->pec = i2c_smbus_pec(0, &addr, 1);
+ /* PEC - SSIF Command */
+ part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
+ /* PEC - Restart Write Address */
+ addr = addr | 0x01;
+ part->pec = i2c_smbus_pec(part->pec, &addr, 1);
+ part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
+ if (part->length)
+ part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
+}
+
+static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ part->length = ssif_bmc->response.len;
+
+ /* Clear the rest to 0 */
+ memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
+ memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
+}
+
+static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ u8 part_len = 0;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_MULTIPART_READ_START:
+ /*
+ * Read Start length is 32 bytes.
+ * Read Start transfer first 30 bytes of IPMI response
+ * and 2 special code 0x00, 0x01.
+ */
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->block_num = 0;
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
+ ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
+
+ part->payload[0] = 0x00; /* Start Flag */
+ part->payload[1] = 0x01; /* Start Flag */
+
+ memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
+ break;
+
+ case SSIF_IPMI_MULTIPART_READ_MIDDLE:
+ /*
+ * IPMI READ Middle or READ End messages can carry up to 31 bytes
+ * IPMI data plus block number byte.
+ */
+ if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
+ /*
+ * This is READ End message
+ * Return length is the remaining response data length
+ * plus block number
+ * Block number 0xFF is to indicate this is last message
+ *
+ */
+ /* Clean the buffer */
+ memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
+ part->length = ssif_bmc->remain_len + 1;
+ part_len = ssif_bmc->remain_len;
+ ssif_bmc->block_num = 0xFF;
+ part->payload[0] = ssif_bmc->block_num;
+ } else {
+ /*
+ * This is READ Middle message
+ * Response length is the maximum SMBUS transfer length
+ * Block number byte is incremented
+ * Return length is maximum SMBUS transfer length
+ */
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
+ part->payload[0] = ssif_bmc->block_num;
+ ssif_bmc->block_num++;
+ }
+
+ ssif_bmc->remain_len -= part_len;
+ memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
+ part_len);
+ break;
+
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+
+ ssif_bmc->nbytes_processed += part_len;
+}
+
+static bool supported_read_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_READ ||
+ cmd == SSIF_IPMI_MULTIPART_READ_START ||
+ cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
+ return true;
+
+ return false;
+}
+
+static bool supported_write_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ return true;
+
+ return false;
+}
+
+/* Process the IPMI response that will be read by master */
+static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ /* msg_idx start from 0 */
+ if (part->index < part->length)
+ *val = part->payload[part->index];
+ else if (part->index == part->length && ssif_bmc->pec_support)
+ *val = part->pec;
+ else
+ *val = 0;
+
+ part->index++;
+}
+
+static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* msg_idx should not be 0 when reach here */
+ if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
+ return;
+
+ if (ssif_bmc->msg_idx == 1) {
+ ssif_bmc->part_buf.length = *val;
+ ssif_bmc->part_buf.index = 0;
+ } else {
+ ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
+ }
+
+ ssif_bmc->msg_idx++;
+}
+
+static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ bool ret = true;
+ u8 cpec;
+ u8 addr;
+
+ if (part->index == part->length) {
+ /* PEC is not included */
+ ssif_bmc->pec_support = false;
+ ret = true;
+ goto exit;
+ }
+
+ if (part->index != part->length + 1) {
+ ret = false;
+ goto exit;
+ }
+
+ /* PEC is included */
+ ssif_bmc->pec_support = true;
+ part->pec = part->payload[part->length];
+ addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ cpec = i2c_smbus_pec(0, &addr, 1);
+ cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
+ cpec = i2c_smbus_pec(cpec, &part->length, 1);
+ /*
+ * As SMBus specification does not allow the length
+ * (byte count) in the Write-Block protocol to be zero.
+ * Therefore, it is illegal to have the last Middle
+ * transaction in the sequence carry 32-byte and have
+ * a length of ‘0’ in the End transaction.
+ * But some users may try to use this way and we should
+ * prevent ssif_bmc driver broken in this case.
+ */
+ if (part->length)
+ cpec = i2c_smbus_pec(cpec, part->payload, part->length);
+
+ if (cpec != part->pec)
+ ret = false;
+
+exit:
+ return ret;
+}
+
+static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_SINGLEPART_WRITE:
+ /* save the whole part to request*/
+ ssif_bmc->request.len = part->length;
+ memcpy(ssif_bmc->request.payload, part->payload, part->length);
+
+ break;
+ case SSIF_IPMI_MULTIPART_WRITE_START:
+ ssif_bmc->request.len = 0;
+
+ fallthrough;
+ case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
+ case SSIF_IPMI_MULTIPART_WRITE_END:
+ /* Do the bound check here, not allow the request len exceed 254 bytes */
+ if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
+ memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
+ part->payload, part->length);
+ ssif_bmc->request.len += part->length;
+ } else {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: Request exceeded 254 bytes, aborting");
+ /* Request too long, aborting */
+ ssif_bmc->aborting = true;
+ }
+ break;
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+}
+
+static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* SMBUS command can vary (single or multi-part) */
+ ssif_bmc->part_buf.smbus_cmd = *val;
+ ssif_bmc->msg_idx = 1;
+
+ if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
+ /*
+ * The response maybe not come in-time, causing host SSIF driver
+ * to timeout and resend a new request. In such case check for
+ * pending response and clear it
+ */
+ if (ssif_bmc->response_in_progress)
+ complete_response(ssif_bmc);
+
+ /* This is new request, flip aborting flag if set */
+ if (ssif_bmc->aborting)
+ ssif_bmc->aborting = false;
+ }
+}
+
+static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ REQUESTED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_RES_SENDING;
+ }
+
+ ssif_bmc->msg_idx = 0;
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ if (ssif_bmc->is_singlepart_read)
+ set_singlepart_response_buffer(ssif_bmc);
+ else
+ set_multipart_response_buffer(ssif_bmc);
+
+ calculate_response_part_pec(&ssif_bmc->part_buf);
+ ssif_bmc->part_buf.index = 0;
+ *val = ssif_bmc->part_buf.length;
+}
+
+static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_SMBUS_CMD) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ PROCESSED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+ }
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ handle_read_processed(ssif_bmc, val);
+}
+
+static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
+ ssif_bmc->state = SSIF_START;
+
+ } else if (ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE REQUEST in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ return;
+ }
+
+ ssif_bmc->msg_idx = 0;
+ ssif_bmc->part_buf.address = *val;
+}
+
+static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+
+ } else if (ssif_bmc->state == SSIF_START) {
+ ssif_bmc->state = SSIF_SMBUS_CMD;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_REQ_RECVING;
+ }
+
+ /* This is response sending state */
+ if (ssif_bmc->state == SSIF_REQ_RECVING)
+ handle_write_received(ssif_bmc, val);
+ else if (ssif_bmc->state == SSIF_SMBUS_CMD)
+ process_smbus_cmd(ssif_bmc, val);
+}
+
+static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_SMBUS_CMD ||
+ ssif_bmc->state == SSIF_ABORTING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected SLAVE STOP in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_READY;
+
+ } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
+ if (validate_request_part(ssif_bmc)) {
+ process_request_part(ssif_bmc);
+ if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ handle_request(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ } else {
+ /*
+ * A BMC that receives an invalid request drop the data for the write
+ * transaction and any further transactions (read or write) until
+ * the next valid read or write Start transaction is received
+ */
+ dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
+ ssif_bmc->aborting = true;
+ }
+ } else if (ssif_bmc->state == SSIF_RES_SENDING) {
+ if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
+ /* Invalidate response buffer to denote it is sent */
+ complete_response(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ }
+
+ /* Reset message index */
+ ssif_bmc->msg_idx = 0;
+}
+
+/*
+ * Callback function to handle I2C slave events
+ */
+static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
+{
+ unsigned long flags;
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+ int ret = 0;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ switch (event) {
+ case I2C_SLAVE_READ_REQUESTED:
+ on_read_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_REQUESTED:
+ on_write_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_READ_PROCESSED:
+ on_read_processed_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_RECEIVED:
+ on_write_received_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_STOP:
+ on_stop_event(ssif_bmc, val);
+ break;
+
+ default:
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
+ break;
+ }
+
+ if (!ssif_bmc->aborting && ssif_bmc->busy)
+ ret = -EBUSY;
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return ret;
+}
+
+static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct ssif_bmc_ctx *ssif_bmc;
+ int ret;
+
+ ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
+ if (!ssif_bmc)
+ return -ENOMEM;
+
+ spin_lock_init(&ssif_bmc->lock);
+
+ init_waitqueue_head(&ssif_bmc->wait_queue);
+ ssif_bmc->request_available = false;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+
+ /* Register misc device interface */
+ ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
+ ssif_bmc->miscdev.name = DEVICE_NAME;
+ ssif_bmc->miscdev.fops = &ssif_bmc_fops;
+ ssif_bmc->miscdev.parent = &client->dev;
+ ret = misc_register(&ssif_bmc->miscdev);
+ if (ret)
+ goto out;
+
+ ssif_bmc->client = client;
+ ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
+
+ /* Register I2C slave */
+ i2c_set_clientdata(client, ssif_bmc);
+ ret = i2c_slave_register(client, ssif_bmc_cb);
+ if (ret) {
+ misc_deregister(&ssif_bmc->miscdev);
+ goto out;
+ }
+
+ return 0;
+out:
+ devm_kfree(&client->dev, ssif_bmc);
+ return ret;
+}
+
+static int ssif_bmc_remove(struct i2c_client *client)
+{
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+
+ i2c_slave_unregister(client);
+ misc_deregister(&ssif_bmc->miscdev);
+
+ return 0;
+}
+
+static const struct of_device_id ssif_bmc_match[] = {
+ { .compatible = "ssif-bmc" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ssif_bmc_match);
+
+static const struct i2c_device_id ssif_bmc_id[] = {
+ { DEVICE_NAME, 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
+
+static struct i2c_driver ssif_bmc_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = ssif_bmc_match,
+ },
+ .probe = ssif_bmc_probe,
+ .remove = ssif_bmc_remove,
+ .id_table = ssif_bmc_id,
+};
+
+module_i2c_driver(ssif_bmc_driver);
+
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
new file mode 100644
index 000000000000..2c3fc2a4698f
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+#ifndef __SSIF_BMC_H__
+#define __SSIF_BMC_H__
+
+#define DEVICE_NAME "ipmi-ssif-host"
+
+#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
+
+/* A standard SMBus Transaction is limited to 32 data bytes */
+#define MAX_PAYLOAD_PER_TRANSACTION 32
+/* Transaction includes the address, the command, the length and the PEC byte */
+#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
+
+#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
+#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
+
+#define SSIF_IPMI_SINGLEPART_WRITE 0x2
+#define SSIF_IPMI_SINGLEPART_READ 0x3
+#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
+#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
+#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
+#define SSIF_IPMI_MULTIPART_READ_START 0x3
+#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
+
+/* Include netfn and cmd field */
+#define MSG_PAYLOAD_LEN_MAX 254
+/*
+ * IPMI 2.0 Spec, section 12.7 SSIF Timing,
+ * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
+ * Recover ssif_bmc from busy state if it takes up to 500ms
+ */
+#define RESPONSE_TIMEOUT 500 /* ms */
+
+struct ssif_msg {
+ u8 len;
+ u8 payload[MSG_PAYLOAD_LEN_MAX];
+} __packed;
+
+struct ssif_part_buffer {
+ u8 address;
+ u8 smbus_cmd;
+ u8 length;
+ u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
+ u8 pec;
+ u8 index;
+} __packed;
+
+/*
+ * SSIF internal states:
+ * SSIF_READY 0x00 : Ready state
+ * SSIF_START 0x01 : Start smbus transaction
+ * SSIF_SMBUS_CMD 0x02 : Received SMBus command
+ * SSIF_REQ_RECVING 0x03 : Receiving request
+ * SSIF_RES_SENDING 0x04 : Sending response
+ * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
+ */
+enum ssif_state {
+ SSIF_READY,
+ SSIF_START,
+ SSIF_SMBUS_CMD,
+ SSIF_REQ_RECVING,
+ SSIF_RES_SENDING,
+ SSIF_ABORTING,
+ SSIF_STATE_MAX
+};
+
+struct ssif_bmc_ctx {
+ struct i2c_client *client;
+ struct miscdevice miscdev;
+ int msg_idx;
+ bool pec_support;
+ /* ssif bmc spinlock */
+ spinlock_t lock;
+ wait_queue_head_t wait_queue;
+ u8 running;
+ enum ssif_state state;
+ /* Timeout waiting for response */
+ struct timer_list response_timer;
+ bool response_timer_inited;
+ /* Flag to identify a Multi-part Read Transaction */
+ bool is_singlepart_read;
+ u8 nbytes_processed;
+ u8 remain_len;
+ u8 recv_len;
+ /* Block Number of a Multi-part Read Transaction */
+ u8 block_num;
+ bool request_available;
+ bool response_in_progress;
+ bool busy;
+ bool aborting;
+ /* Buffer for SSIF Transaction part*/
+ struct ssif_part_buffer part_buf;
+ struct ssif_msg response;
+ struct ssif_msg request;
+};
+
+static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
+{
+ return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
+}
+#endif /* __SSIF_BMC_H__ */
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
in-band IPMI communication with their host in management (BMC) side.
Thanks Dan for the copy_from_user() fix in the link below.
Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Remove unneccessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]
v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]
v5:
+ None
v4:
+ Send response with Completion code 0xFF when aborting [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, dont
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]
v3:
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Removed mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
v2:
+ Fixed compiling error with COMPILE_TEST for arc
drivers/char/ipmi/Kconfig | 11 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
drivers/char/ipmi/ssif_bmc.h | 107 +++++
4 files changed, 899 insertions(+)
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 drivers/char/ipmi/ssif_bmc.h
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index b061e6b513ed..18a89093d64e 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
found on Aspeed SOCs (AST2400 and AST2500). The driver
implements the BMC side of the BT interface.
+config SSIF_IPMI_BMC
+ tristate "SSIF IPMI BMC driver"
+ select I2C
+ select I2C_SLAVE
+ help
+ This enables the IPMI SMBus system interface (SSIF) at the
+ management (BMC) side.
+
+ The driver implements the BMC side of the SMBus system
+ interface (SSIF).
+
config IPMB_DEVICE_INTERFACE
tristate 'IPMB Interface handler'
depends on I2C
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 7ce790efad92..cb6138b8ded9 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
+obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
new file mode 100644
index 000000000000..4cff5e1a075e
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.c
@@ -0,0 +1,780 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+
+#include "ssif_bmc.h"
+
+static const char *state_to_string(enum ssif_state state)
+{
+ switch (state) {
+ case SSIF_READY:
+ return "SSIF_READY";
+ case SSIF_START:
+ return "SSIF_START";
+ case SSIF_SMBUS_CMD:
+ return "SSIF_SMBUS_CMD";
+ case SSIF_REQ_RECVING:
+ return "SSIF_REQ_RECVING";
+ case SSIF_RES_SENDING:
+ return "SSIF_RES_SENDING";
+ case SSIF_ABORTING:
+ return "SSIF_ABORTING";
+ default:
+ return "SSIF_STATE_UNKNOWN";
+ }
+}
+
+/* Handle SSIF message that will be sent to user */
+static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (!ssif_bmc->request_available) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ ssif_bmc->request_available);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ ret = -EINVAL;
+ } else {
+ count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
+ memcpy(&msg, &ssif_bmc->request, count);
+ ssif_bmc->request_available = false;
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ ret = copy_to_user(buf, &msg, count);
+ }
+
+ return (ret < 0) ? ret : count;
+}
+
+/* Handle SSIF message that is written by user */
+static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ struct ssif_msg msg;
+ unsigned long flags;
+ ssize_t ret;
+
+ if (count > sizeof(struct ssif_msg))
+ return -EINVAL;
+
+ if (copy_from_user(&msg, buf, count))
+ return -EFAULT;
+
+ if (!msg.len || count < msg.len + 1)
+ return -EINVAL;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ while (ssif_bmc->response_in_progress) {
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(ssif_bmc->wait_queue,
+ !ssif_bmc->response_in_progress);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+ }
+
+ /*
+ * The write must complete before the response timeout fired, otherwise
+ * the response is aborted and wait for next request
+ * Return -EINVAL if the response is aborted
+ */
+ ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
+ if (ret)
+ goto exit;
+
+ del_timer(&ssif_bmc->response_timer);
+ ssif_bmc->response_timer_inited = false;
+
+ memcpy(&ssif_bmc->response, &msg, count);
+ ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
+
+ ssif_bmc->response_in_progress = true;
+
+ /* ssif_bmc not busy */
+ ssif_bmc->busy = false;
+
+ /* Clean old request buffer */
+ memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
+exit:
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return (ret < 0) ? ret : count;
+}
+
+static int ssif_bmc_open(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ int ret = 0;
+
+ spin_lock_irq(&ssif_bmc->lock);
+ if (!ssif_bmc->running)
+ ssif_bmc->running = 1;
+ else
+ ret = -EBUSY;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return ret;
+}
+
+static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+ __poll_t mask = 0;
+
+ poll_wait(file, &ssif_bmc->wait_queue, wait);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ /* The request is available, userspace application can get the request */
+ if (ssif_bmc->request_available)
+ mask |= POLLIN;
+
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return mask;
+}
+
+static int ssif_bmc_release(struct inode *inode, struct file *file)
+{
+ struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
+
+ spin_lock_irq(&ssif_bmc->lock);
+ ssif_bmc->running = 0;
+ spin_unlock_irq(&ssif_bmc->lock);
+
+ return 0;
+}
+
+/*
+ * System calls to device interface for user apps
+ */
+static const struct file_operations ssif_bmc_fops = {
+ .owner = THIS_MODULE,
+ .open = ssif_bmc_open,
+ .read = ssif_bmc_read,
+ .write = ssif_bmc_write,
+ .release = ssif_bmc_release,
+ .poll = ssif_bmc_poll,
+};
+
+/* Called with ssif_bmc->lock held. */
+static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* Invalidate response in buffer to denote it having been sent. */
+ ssif_bmc->response.len = 0;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->remain_len = 0;
+ ssif_bmc->busy = false;
+ memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
+ wake_up_all(&ssif_bmc->wait_queue);
+}
+
+static void response_timeout(struct timer_list *t)
+{
+ struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ /* Do nothing if the response is in progress */
+ if (!ssif_bmc->response_in_progress) {
+ /* Recover ssif_bmc from busy */
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+ /* Set aborting flag */
+ ssif_bmc->aborting = true;
+ }
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+}
+
+/* Called with ssif_bmc->lock held. */
+static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
+{
+ /* set ssif_bmc to busy waiting for response */
+ ssif_bmc->busy = true;
+ /* Request message is available to process */
+ ssif_bmc->request_available = true;
+ /* Clean old response buffer */
+ memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
+ /* This is the new READ request.*/
+ wake_up_all(&ssif_bmc->wait_queue);
+
+ /* Armed timer to recover slave from busy state in case of no response */
+ if (!ssif_bmc->response_timer_inited) {
+ timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
+ ssif_bmc->response_timer_inited = true;
+ }
+ mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
+}
+
+static void calculate_response_part_pec(struct ssif_part_buffer *part)
+{
+ u8 addr = part->address;
+
+ /* PEC - Start Read Address */
+ part->pec = i2c_smbus_pec(0, &addr, 1);
+ /* PEC - SSIF Command */
+ part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
+ /* PEC - Restart Write Address */
+ addr = addr | 0x01;
+ part->pec = i2c_smbus_pec(part->pec, &addr, 1);
+ part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
+ if (part->length)
+ part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
+}
+
+static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ part->length = ssif_bmc->response.len;
+
+ /* Clear the rest to 0 */
+ memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
+ memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
+}
+
+static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ u8 part_len = 0;
+
+ part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_MULTIPART_READ_START:
+ /*
+ * Read Start length is 32 bytes.
+ * Read Start transfer first 30 bytes of IPMI response
+ * and 2 special code 0x00, 0x01.
+ */
+ ssif_bmc->nbytes_processed = 0;
+ ssif_bmc->block_num = 0;
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
+ ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
+
+ part->payload[0] = 0x00; /* Start Flag */
+ part->payload[1] = 0x01; /* Start Flag */
+
+ memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
+ break;
+
+ case SSIF_IPMI_MULTIPART_READ_MIDDLE:
+ /*
+ * IPMI READ Middle or READ End messages can carry up to 31 bytes
+ * IPMI data plus block number byte.
+ */
+ if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
+ /*
+ * This is READ End message
+ * Return length is the remaining response data length
+ * plus block number
+ * Block number 0xFF is to indicate this is last message
+ *
+ */
+ /* Clean the buffer */
+ memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
+ part->length = ssif_bmc->remain_len + 1;
+ part_len = ssif_bmc->remain_len;
+ ssif_bmc->block_num = 0xFF;
+ part->payload[0] = ssif_bmc->block_num;
+ } else {
+ /*
+ * This is READ Middle message
+ * Response length is the maximum SMBUS transfer length
+ * Block number byte is incremented
+ * Return length is maximum SMBUS transfer length
+ */
+ part->length = MAX_PAYLOAD_PER_TRANSACTION;
+ part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
+ part->payload[0] = ssif_bmc->block_num;
+ ssif_bmc->block_num++;
+ }
+
+ ssif_bmc->remain_len -= part_len;
+ memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
+ part_len);
+ break;
+
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+
+ ssif_bmc->nbytes_processed += part_len;
+}
+
+static bool supported_read_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_READ ||
+ cmd == SSIF_IPMI_MULTIPART_READ_START ||
+ cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
+ return true;
+
+ return false;
+}
+
+static bool supported_write_cmd(u8 cmd)
+{
+ if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
+ cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ return true;
+
+ return false;
+}
+
+/* Process the IPMI response that will be read by master */
+static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ /* msg_idx start from 0 */
+ if (part->index < part->length)
+ *val = part->payload[part->index];
+ else if (part->index == part->length && ssif_bmc->pec_support)
+ *val = part->pec;
+ else
+ *val = 0;
+
+ part->index++;
+}
+
+static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* msg_idx should not be 0 when reach here */
+ if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
+ return;
+
+ if (ssif_bmc->msg_idx == 1) {
+ ssif_bmc->part_buf.length = *val;
+ ssif_bmc->part_buf.index = 0;
+ } else {
+ ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
+ }
+
+ ssif_bmc->msg_idx++;
+}
+
+static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+ bool ret = true;
+ u8 cpec;
+ u8 addr;
+
+ if (part->index == part->length) {
+ /* PEC is not included */
+ ssif_bmc->pec_support = false;
+ ret = true;
+ goto exit;
+ }
+
+ if (part->index != part->length + 1) {
+ ret = false;
+ goto exit;
+ }
+
+ /* PEC is included */
+ ssif_bmc->pec_support = true;
+ part->pec = part->payload[part->length];
+ addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
+ cpec = i2c_smbus_pec(0, &addr, 1);
+ cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
+ cpec = i2c_smbus_pec(cpec, &part->length, 1);
+ /*
+ * As SMBus specification does not allow the length
+ * (byte count) in the Write-Block protocol to be zero.
+ * Therefore, it is illegal to have the last Middle
+ * transaction in the sequence carry 32-byte and have
+ * a length of ‘0’ in the End transaction.
+ * But some users may try to use this way and we should
+ * prevent ssif_bmc driver broken in this case.
+ */
+ if (part->length)
+ cpec = i2c_smbus_pec(cpec, part->payload, part->length);
+
+ if (cpec != part->pec)
+ ret = false;
+
+exit:
+ return ret;
+}
+
+static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
+{
+ struct ssif_part_buffer *part = &ssif_bmc->part_buf;
+
+ switch (part->smbus_cmd) {
+ case SSIF_IPMI_SINGLEPART_WRITE:
+ /* save the whole part to request*/
+ ssif_bmc->request.len = part->length;
+ memcpy(ssif_bmc->request.payload, part->payload, part->length);
+
+ break;
+ case SSIF_IPMI_MULTIPART_WRITE_START:
+ ssif_bmc->request.len = 0;
+
+ fallthrough;
+ case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
+ case SSIF_IPMI_MULTIPART_WRITE_END:
+ /* Do the bound check here, not allow the request len exceed 254 bytes */
+ if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
+ memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
+ part->payload, part->length);
+ ssif_bmc->request.len += part->length;
+ } else {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: Request exceeded 254 bytes, aborting");
+ /* Request too long, aborting */
+ ssif_bmc->aborting = true;
+ }
+ break;
+ default:
+ /* Do not expect to go to this case */
+ dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
+ __func__, part->smbus_cmd);
+ break;
+ }
+}
+
+static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ /* SMBUS command can vary (single or multi-part) */
+ ssif_bmc->part_buf.smbus_cmd = *val;
+ ssif_bmc->msg_idx = 1;
+
+ if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
+ /*
+ * The response maybe not come in-time, causing host SSIF driver
+ * to timeout and resend a new request. In such case check for
+ * pending response and clear it
+ */
+ if (ssif_bmc->response_in_progress)
+ complete_response(ssif_bmc);
+
+ /* This is new request, flip aborting flag if set */
+ if (ssif_bmc->aborting)
+ ssif_bmc->aborting = false;
+ }
+}
+
+static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ REQUESTED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_RES_SENDING;
+ }
+
+ ssif_bmc->msg_idx = 0;
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ if (ssif_bmc->is_singlepart_read)
+ set_singlepart_response_buffer(ssif_bmc);
+ else
+ set_multipart_response_buffer(ssif_bmc);
+
+ calculate_response_part_pec(&ssif_bmc->part_buf);
+ ssif_bmc->part_buf.index = 0;
+ *val = ssif_bmc->part_buf.length;
+}
+
+static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_SMBUS_CMD) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected READ PROCESSED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ *val = 0;
+ return;
+ }
+
+ /* Send 0 if there is nothing to send */
+ if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
+ *val = 0;
+ return;
+ }
+
+ handle_read_processed(ssif_bmc, val);
+}
+
+static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
+ ssif_bmc->state = SSIF_START;
+
+ } else if (ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_REQ_RECVING ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE REQUEST in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+ return;
+ }
+
+ ssif_bmc->msg_idx = 0;
+ ssif_bmc->part_buf.address = *val;
+}
+
+static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_RES_SENDING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_ABORTING;
+
+ } else if (ssif_bmc->state == SSIF_START) {
+ ssif_bmc->state = SSIF_SMBUS_CMD;
+
+ } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
+ if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
+ ssif_bmc->part_buf.smbus_cmd);
+ ssif_bmc->aborting = true;
+ }
+
+ if (ssif_bmc->aborting)
+ ssif_bmc->state = SSIF_ABORTING;
+ else
+ ssif_bmc->state = SSIF_REQ_RECVING;
+ }
+
+ /* This is response sending state */
+ if (ssif_bmc->state == SSIF_REQ_RECVING)
+ handle_write_received(ssif_bmc, val);
+ else if (ssif_bmc->state == SSIF_SMBUS_CMD)
+ process_smbus_cmd(ssif_bmc, val);
+}
+
+static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
+{
+ if (ssif_bmc->state == SSIF_READY ||
+ ssif_bmc->state == SSIF_START ||
+ ssif_bmc->state == SSIF_SMBUS_CMD ||
+ ssif_bmc->state == SSIF_ABORTING) {
+ dev_warn(&ssif_bmc->client->dev,
+ "Warn: %s unexpected SLAVE STOP in state=%s\n",
+ __func__, state_to_string(ssif_bmc->state));
+ ssif_bmc->state = SSIF_READY;
+
+ } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
+ if (validate_request_part(ssif_bmc)) {
+ process_request_part(ssif_bmc);
+ if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
+ ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
+ handle_request(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ } else {
+ /*
+ * A BMC that receives an invalid request drop the data for the write
+ * transaction and any further transactions (read or write) until
+ * the next valid read or write Start transaction is received
+ */
+ dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
+ ssif_bmc->aborting = true;
+ }
+ } else if (ssif_bmc->state == SSIF_RES_SENDING) {
+ if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
+ /* Invalidate response buffer to denote it is sent */
+ complete_response(ssif_bmc);
+ ssif_bmc->state = SSIF_READY;
+ }
+
+ /* Reset message index */
+ ssif_bmc->msg_idx = 0;
+}
+
+/*
+ * Callback function to handle I2C slave events
+ */
+static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
+{
+ unsigned long flags;
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+ int ret = 0;
+
+ spin_lock_irqsave(&ssif_bmc->lock, flags);
+
+ switch (event) {
+ case I2C_SLAVE_READ_REQUESTED:
+ on_read_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_REQUESTED:
+ on_write_requested_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_READ_PROCESSED:
+ on_read_processed_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_WRITE_RECEIVED:
+ on_write_received_event(ssif_bmc, val);
+ break;
+
+ case I2C_SLAVE_STOP:
+ on_stop_event(ssif_bmc, val);
+ break;
+
+ default:
+ dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
+ break;
+ }
+
+ if (!ssif_bmc->aborting && ssif_bmc->busy)
+ ret = -EBUSY;
+
+ spin_unlock_irqrestore(&ssif_bmc->lock, flags);
+
+ return ret;
+}
+
+static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct ssif_bmc_ctx *ssif_bmc;
+ int ret;
+
+ ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
+ if (!ssif_bmc)
+ return -ENOMEM;
+
+ spin_lock_init(&ssif_bmc->lock);
+
+ init_waitqueue_head(&ssif_bmc->wait_queue);
+ ssif_bmc->request_available = false;
+ ssif_bmc->response_in_progress = false;
+ ssif_bmc->busy = false;
+ ssif_bmc->response_timer_inited = false;
+
+ /* Register misc device interface */
+ ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
+ ssif_bmc->miscdev.name = DEVICE_NAME;
+ ssif_bmc->miscdev.fops = &ssif_bmc_fops;
+ ssif_bmc->miscdev.parent = &client->dev;
+ ret = misc_register(&ssif_bmc->miscdev);
+ if (ret)
+ goto out;
+
+ ssif_bmc->client = client;
+ ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
+
+ /* Register I2C slave */
+ i2c_set_clientdata(client, ssif_bmc);
+ ret = i2c_slave_register(client, ssif_bmc_cb);
+ if (ret) {
+ misc_deregister(&ssif_bmc->miscdev);
+ goto out;
+ }
+
+ return 0;
+out:
+ devm_kfree(&client->dev, ssif_bmc);
+ return ret;
+}
+
+static int ssif_bmc_remove(struct i2c_client *client)
+{
+ struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
+
+ i2c_slave_unregister(client);
+ misc_deregister(&ssif_bmc->miscdev);
+
+ return 0;
+}
+
+static const struct of_device_id ssif_bmc_match[] = {
+ { .compatible = "ssif-bmc" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ssif_bmc_match);
+
+static const struct i2c_device_id ssif_bmc_id[] = {
+ { DEVICE_NAME, 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
+
+static struct i2c_driver ssif_bmc_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = ssif_bmc_match,
+ },
+ .probe = ssif_bmc_probe,
+ .remove = ssif_bmc_remove,
+ .id_table = ssif_bmc_id,
+};
+
+module_i2c_driver(ssif_bmc_driver);
+
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
new file mode 100644
index 000000000000..2c3fc2a4698f
--- /dev/null
+++ b/drivers/char/ipmi/ssif_bmc.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * The driver for BMC side of SSIF interface
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+#ifndef __SSIF_BMC_H__
+#define __SSIF_BMC_H__
+
+#define DEVICE_NAME "ipmi-ssif-host"
+
+#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
+
+/* A standard SMBus Transaction is limited to 32 data bytes */
+#define MAX_PAYLOAD_PER_TRANSACTION 32
+/* Transaction includes the address, the command, the length and the PEC byte */
+#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
+
+#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
+#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
+
+#define SSIF_IPMI_SINGLEPART_WRITE 0x2
+#define SSIF_IPMI_SINGLEPART_READ 0x3
+#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
+#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
+#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
+#define SSIF_IPMI_MULTIPART_READ_START 0x3
+#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
+
+/* Include netfn and cmd field */
+#define MSG_PAYLOAD_LEN_MAX 254
+/*
+ * IPMI 2.0 Spec, section 12.7 SSIF Timing,
+ * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
+ * Recover ssif_bmc from busy state if it takes up to 500ms
+ */
+#define RESPONSE_TIMEOUT 500 /* ms */
+
+struct ssif_msg {
+ u8 len;
+ u8 payload[MSG_PAYLOAD_LEN_MAX];
+} __packed;
+
+struct ssif_part_buffer {
+ u8 address;
+ u8 smbus_cmd;
+ u8 length;
+ u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
+ u8 pec;
+ u8 index;
+} __packed;
+
+/*
+ * SSIF internal states:
+ * SSIF_READY 0x00 : Ready state
+ * SSIF_START 0x01 : Start smbus transaction
+ * SSIF_SMBUS_CMD 0x02 : Received SMBus command
+ * SSIF_REQ_RECVING 0x03 : Receiving request
+ * SSIF_RES_SENDING 0x04 : Sending response
+ * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
+ */
+enum ssif_state {
+ SSIF_READY,
+ SSIF_START,
+ SSIF_SMBUS_CMD,
+ SSIF_REQ_RECVING,
+ SSIF_RES_SENDING,
+ SSIF_ABORTING,
+ SSIF_STATE_MAX
+};
+
+struct ssif_bmc_ctx {
+ struct i2c_client *client;
+ struct miscdevice miscdev;
+ int msg_idx;
+ bool pec_support;
+ /* ssif bmc spinlock */
+ spinlock_t lock;
+ wait_queue_head_t wait_queue;
+ u8 running;
+ enum ssif_state state;
+ /* Timeout waiting for response */
+ struct timer_list response_timer;
+ bool response_timer_inited;
+ /* Flag to identify a Multi-part Read Transaction */
+ bool is_singlepart_read;
+ u8 nbytes_processed;
+ u8 remain_len;
+ u8 recv_len;
+ /* Block Number of a Multi-part Read Transaction */
+ u8 block_num;
+ bool request_available;
+ bool response_in_progress;
+ bool busy;
+ bool aborting;
+ /* Buffer for SSIF Transaction part*/
+ struct ssif_part_buffer part_buf;
+ struct ssif_msg response;
+ struct ssif_msg request;
+};
+
+static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
+{
+ return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
+}
+#endif /* __SSIF_BMC_H__ */
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:08 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Add device tree binding document for the SSIF BMC driver.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
v6:
+ None
v5:
+ None
v4:
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
v3:
+ Switched to use DT schema format [Rob]
v2:
+ None
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
new file mode 100644
index 000000000000..02b662d780bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SSIF IPMI BMC interface
+
+description: SSIF IPMI BMC device bindings
+
+maintainers:
+ - Quan Nguyen <quan@os.amperecomputing.com>
+
+properties:
+ compatible:
+ enum:
+ - ssif-bmc
+
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssif-bmc@10 {
+ compatible = "ssif-bmc";
+ reg = <0x10>;
+ };
+ };
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Add device tree binding document for the SSIF BMC driver.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
v6:
+ None
v5:
+ None
v4:
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
v3:
+ Switched to use DT schema format [Rob]
v2:
+ None
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
new file mode 100644
index 000000000000..02b662d780bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SSIF IPMI BMC interface
+
+description: SSIF IPMI BMC device bindings
+
+maintainers:
+ - Quan Nguyen <quan@os.amperecomputing.com>
+
+properties:
+ compatible:
+ enum:
+ - ssif-bmc
+
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssif-bmc@10 {
+ compatible = "ssif-bmc";
+ reg = <0x10>;
+ };
+ };
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
Add device tree binding document for the SSIF BMC driver.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
v6:
+ None
v5:
+ None
v4:
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
v3:
+ Switched to use DT schema format [Rob]
v2:
+ None
.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
new file mode 100644
index 000000000000..02b662d780bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SSIF IPMI BMC interface
+
+description: SSIF IPMI BMC device bindings
+
+maintainers:
+ - Quan Nguyen <quan@os.amperecomputing.com>
+
+properties:
+ compatible:
+ enum:
+ - ssif-bmc
+
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ ssif-bmc@10 {
+ compatible = "ssif-bmc";
+ reg = <0x10>;
+ };
+ };
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:08 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
-EBUSY, i2c controller should issue RxCmdLast command to assert NAK
on the bus.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ None
v6:
+ New introduced in v6 [Quan]
drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 771e53d3d197..ebc2b92656c8 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
u32 command, irq_handled = 0;
struct i2c_client *slave = bus->slave;
u8 value;
+ int ret;
if (!slave)
return 0;
@@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
break;
case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
- i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ if (ret == -EBUSY)
+ writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
break;
case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
-EBUSY, i2c controller should issue RxCmdLast command to assert NAK
on the bus.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ None
v6:
+ New introduced in v6 [Quan]
drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 771e53d3d197..ebc2b92656c8 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
u32 command, irq_handled = 0;
struct i2c_client *slave = bus->slave;
u8 value;
+ int ret;
if (!slave)
return 0;
@@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
break;
case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
- i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ if (ret == -EBUSY)
+ writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
break;
case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 67+ messages in thread
* [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-04-22 4:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:08 UTC (permalink / raw)
To: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
Wolfram Sang, openipmi-developer, devicetree, linux-arm-kernel,
linux-aspeed, linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
-EBUSY, i2c controller should issue RxCmdLast command to assert NAK
on the bus.
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
v7:
+ None
v6:
+ New introduced in v6 [Quan]
drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 771e53d3d197..ebc2b92656c8 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
u32 command, irq_handled = 0;
struct i2c_client *slave = bus->slave;
u8 value;
+ int ret;
if (!slave)
return 0;
@@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
break;
case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
- i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ if (ret == -EBUSY)
+ writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
break;
case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
--
2.35.1
^ permalink raw reply related [flat|nested] 67+ messages in thread
* Re: [PATCH v7 0/3] Add SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:16 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> This series add support the SSIF BMC driver which is to perform in-band
> IPMI communication with their host in management (BMC) side.
>
> SSIF BMC driver in this series is tested with Aspeed AST2500.
>
> Discussion for v6: https://lkml.org/lkml/2022/3/10/340
>
> v7:
> + Remove unnecessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + Correct the patches order to fix the bisect issue found by
> kernel build robot
>
> v4:
> + Fix recursive spinlock [Graeme]
> + Send response with Completion code 0xFF when aborting [Quan]
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, don't
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
> + Added slave_enable() to struct i2c_algorithm to control
> slave mode and to address the recursive spinlock [Graeme, Ryan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Switched binding doc to use DT schema format [Rob]
> + Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Remove mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
> + Combine mask/unmask two interrupts together [Corey]
> + Fixed unhandled Tx done with NAK [Quan]
> + Late ack'ed Tx done w/wo Ack irq [Quan]
> + Use aspeed-specific exported aspeed_set_slave_busy() when
> slave busy to fix the deadlock [Graeme, Philipp, Quan]
> + Clean buffer for last multipart read [Quan]
> + Handle unknown incoming command [Quan]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> Quan Nguyen (3):
> ipmi: ssif_bmc: Add SSIF BMC driver
> bindings: ipmi: Add binding for SSIF BMC driver
> i2c: aspeed: Assert NAK when slave is busy
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++
> drivers/i2c/busses/i2c-aspeed.c | 5 +-
> 6 files changed, 941 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 0/3] Add SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> This series add support the SSIF BMC driver which is to perform in-band
> IPMI communication with their host in management (BMC) side.
>
> SSIF BMC driver in this series is tested with Aspeed AST2500.
>
> Discussion for v6: https://lkml.org/lkml/2022/3/10/340
>
> v7:
> + Remove unnecessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + Correct the patches order to fix the bisect issue found by
> kernel build robot
>
> v4:
> + Fix recursive spinlock [Graeme]
> + Send response with Completion code 0xFF when aborting [Quan]
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, don't
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
> + Added slave_enable() to struct i2c_algorithm to control
> slave mode and to address the recursive spinlock [Graeme, Ryan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Switched binding doc to use DT schema format [Rob]
> + Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Remove mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
> + Combine mask/unmask two interrupts together [Corey]
> + Fixed unhandled Tx done with NAK [Quan]
> + Late ack'ed Tx done w/wo Ack irq [Quan]
> + Use aspeed-specific exported aspeed_set_slave_busy() when
> slave busy to fix the deadlock [Graeme, Philipp, Quan]
> + Clean buffer for last multipart read [Quan]
> + Handle unknown incoming command [Quan]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> Quan Nguyen (3):
> ipmi: ssif_bmc: Add SSIF BMC driver
> bindings: ipmi: Add binding for SSIF BMC driver
> i2c: aspeed: Assert NAK when slave is busy
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++
> drivers/i2c/busses/i2c-aspeed.c | 5 +-
> 6 files changed, 941 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 0/3] Add SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> This series add support the SSIF BMC driver which is to perform in-band
> IPMI communication with their host in management (BMC) side.
>
> SSIF BMC driver in this series is tested with Aspeed AST2500.
>
> Discussion for v6: https://lkml.org/lkml/2022/3/10/340
>
> v7:
> + Remove unnecessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + Correct the patches order to fix the bisect issue found by
> kernel build robot
>
> v4:
> + Fix recursive spinlock [Graeme]
> + Send response with Completion code 0xFF when aborting [Quan]
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, don't
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
> + Added slave_enable() to struct i2c_algorithm to control
> slave mode and to address the recursive spinlock [Graeme, Ryan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Switched binding doc to use DT schema format [Rob]
> + Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Remove mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
> + Combine mask/unmask two interrupts together [Corey]
> + Fixed unhandled Tx done with NAK [Quan]
> + Late ack'ed Tx done w/wo Ack irq [Quan]
> + Use aspeed-specific exported aspeed_set_slave_busy() when
> slave busy to fix the deadlock [Graeme, Philipp, Quan]
> + Clean buffer for last multipart read [Quan]
> + Handle unknown incoming command [Quan]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> Quan Nguyen (3):
> ipmi: ssif_bmc: Add SSIF BMC driver
> bindings: ipmi: Add binding for SSIF BMC driver
> i2c: aspeed: Assert NAK when slave is busy
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 ++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++
> drivers/i2c/busses/i2c-aspeed.c | 5 +-
> 6 files changed, 941 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
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^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:16 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
> +struct ssif_msg {
> + u8 len;
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
> +struct ssif_msg {
> + u8 len;
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
> +struct ssif_msg {
> + u8 len;
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:16 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
> diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> new file mode 100644
> index 000000000000..02b662d780bb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> @@ -0,0 +1,38 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: SSIF IPMI BMC interface
> +
> +description: SSIF IPMI BMC device bindings
> +
> +maintainers:
> + - Quan Nguyen <quan@os.amperecomputing.com>
> +
> +properties:
> + compatible:
> + enum:
> + - ssif-bmc
> +
> + reg:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + ssif-bmc@10 {
> + compatible = "ssif-bmc";
> + reg = <0x10>;
> + };
> + };
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
> diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> new file mode 100644
> index 000000000000..02b662d780bb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> @@ -0,0 +1,38 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: SSIF IPMI BMC interface
> +
> +description: SSIF IPMI BMC device bindings
> +
> +maintainers:
> + - Quan Nguyen <quan@os.amperecomputing.com>
> +
> +properties:
> + compatible:
> + enum:
> + - ssif-bmc
> +
> + reg:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + ssif-bmc@10 {
> + compatible = "ssif-bmc";
> + reg = <0x10>;
> + };
> + };
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 4:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:16 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
> diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> new file mode 100644
> index 000000000000..02b662d780bb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
> @@ -0,0 +1,38 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/ipmi/ssif-bmc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: SSIF IPMI BMC interface
> +
> +description: SSIF IPMI BMC device bindings
> +
> +maintainers:
> + - Quan Nguyen <quan@os.amperecomputing.com>
> +
> +properties:
> + compatible:
> + enum:
> + - ssif-bmc
> +
> + reg:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + ssif-bmc@10 {
> + compatible = "ssif-bmc";
> + reg = <0x10>;
> + };
> + };
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-22 4:17 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:17 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + None
>
> v6:
> + New introduced in v6 [Quan]
>
> drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 771e53d3d197..ebc2b92656c8 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> u32 command, irq_handled = 0;
> struct i2c_client *slave = bus->slave;
> u8 value;
> + int ret;
>
> if (!slave)
> return 0;
> @@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> break;
> case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
> bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
> - i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + if (ret == -EBUSY)
> + writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
> break;
> case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
> i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-04-22 4:17 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:17 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + None
>
> v6:
> + New introduced in v6 [Quan]
>
> drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 771e53d3d197..ebc2b92656c8 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> u32 command, irq_handled = 0;
> struct i2c_client *slave = bus->slave;
> u8 value;
> + int ret;
>
> if (!slave)
> return 0;
> @@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> break;
> case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
> bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
> - i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + if (ret == -EBUSY)
> + writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
> break;
> case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
> i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-04-22 4:17 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 4:17 UTC (permalink / raw)
To: Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan
On 22/04/2022 11:08, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + None
>
> v6:
> + New introduced in v6 [Quan]
>
> drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 771e53d3d197..ebc2b92656c8 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -244,6 +244,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> u32 command, irq_handled = 0;
> struct i2c_client *slave = bus->slave;
> u8 value;
> + int ret;
>
> if (!slave)
> return 0;
> @@ -311,7 +312,9 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> break;
> case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
> bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
> - i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> + if (ret == -EBUSY)
> + writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
> break;
> case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
> i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
2022-04-22 4:16 ` Quan Nguyen
@ 2022-04-22 7:21 ` Krzysztof Kozlowski
-1 siblings, 0 replies; 67+ messages in thread
From: Krzysztof Kozlowski @ 2022-04-22 7:21 UTC (permalink / raw)
To: Quan Nguyen, Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
On 22/04/2022 06:16, Quan Nguyen wrote:
> Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
> as I'm not aware of the email change
The email change from @canonical.com was 1.5 months ago, so it would be
better if rebase your changes on more recent Linux kernel. You get all
proper .mailmap entries.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 7:21 ` Krzysztof Kozlowski
0 siblings, 0 replies; 67+ messages in thread
From: Krzysztof Kozlowski @ 2022-04-22 7:21 UTC (permalink / raw)
To: Quan Nguyen, Krzysztof Kozlowski, Corey Minyard, Rob Herring,
Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
On 22/04/2022 06:16, Quan Nguyen wrote:
> Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
> as I'm not aware of the email change
The email change from @canonical.com was 1.5 months ago, so it would be
better if rebase your changes on more recent Linux kernel. You get all
proper .mailmap entries.
Best regards,
Krzysztof
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
2022-04-22 7:21 ` Krzysztof Kozlowski
(?)
@ 2022-04-22 7:56 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 7:56 UTC (permalink / raw)
To: Krzysztof Kozlowski, Krzysztof Kozlowski, Corey Minyard,
Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
My apology, Krzysztof.
This patchset was rebased with the tag next-20220421.
And it was my fault actually.
I was using last revision's recipient list after compare recipient names
with the output of get_maintainer.pl to make sure everyone included. But
I missed that your email @canonical.com was changed.
Will be more carefully next time.
Best regards,
- Quan
On 22/04/2022 14:21, Krzysztof Kozlowski wrote:
> On 22/04/2022 06:16, Quan Nguyen wrote:
>> Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
>> as I'm not aware of the email change
>
> The email change from @canonical.com was 1.5 months ago, so it would be
> better if rebase your changes on more recent Linux kernel. You get all
> proper .mailmap entries.
>
>
> Best regards,
> Krzysztof
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 7:56 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 7:56 UTC (permalink / raw)
To: Krzysztof Kozlowski, Krzysztof Kozlowski, Corey Minyard,
Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Thang Q . Nguyen, Phong Vo
My apology, Krzysztof.
This patchset was rebased with the tag next-20220421.
And it was my fault actually.
I was using last revision's recipient list after compare recipient names
with the output of get_maintainer.pl to make sure everyone included. But
I missed that your email @canonical.com was changed.
Will be more carefully next time.
Best regards,
- Quan
On 22/04/2022 14:21, Krzysztof Kozlowski wrote:
> On 22/04/2022 06:16, Quan Nguyen wrote:
>> Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
>> as I'm not aware of the email change
>
> The email change from @canonical.com was 1.5 months ago, so it would be
> better if rebase your changes on more recent Linux kernel. You get all
> proper .mailmap entries.
>
>
> Best regards,
> Krzysztof
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-22 7:56 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-04-22 7:56 UTC (permalink / raw)
To: Krzysztof Kozlowski, Krzysztof Kozlowski, Corey Minyard,
Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc
Cc: Open Source Submission, Phong Vo, Thang Q . Nguyen
My apology, Krzysztof.
This patchset was rebased with the tag next-20220421.
And it was my fault actually.
I was using last revision's recipient list after compare recipient names
with the output of get_maintainer.pl to make sure everyone included. But
I missed that your email @canonical.com was changed.
Will be more carefully next time.
Best regards,
- Quan
On 22/04/2022 14:21, Krzysztof Kozlowski wrote:
> On 22/04/2022 06:16, Quan Nguyen wrote:
>> Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
>> as I'm not aware of the email change
>
> The email change from @canonical.com was 1.5 months ago, so it would be
> better if rebase your changes on more recent Linux kernel. You get all
> proper .mailmap entries.
>
>
> Best regards,
> Krzysztof
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-23 1:51 ` Corey Minyard
-1 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-04-23 1:51 UTC (permalink / raw)
To: Quan Nguyen
Cc: Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
This is much better, the handling of lengths and indexes is much easier
to understand. I hope you agree.
I may be repeating myself on some things, it's been a while since the
last submit. So please forgive me if I do.
Comments inline...
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
Shouldn't this be <=? If you were sending something that was exactly 94
bytes, for instance, you should have a 32-byte start, a 31-byte middle,
and a 31-byte end. If you don't have <= here, you would have a start, two
31-byte middles, and a zero-length end, which is forbidden by the spec.
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
Should be >= 0 here? If not, (PEC maybe?) you should document why,
because it raises red flags.
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
Spacing issue here. You need to run patches through checkpatch.pl
before submitting them. Also, the empty lines here and above are
inconsistent with the rest of the file.
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
Again, the <= is not normal for this check. If it's correct, it needs
to be documented.
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
Is there any value in having a separate .h file for this? Unless you
want to share something with the IPMI host side, which might make sense
on some of the message numbers, but not a big deal, and even then you
could put the .h file with the .c files.
Except for the userspace API, which I will address later.
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
I seem to remember mentioning this before, but there is no reason to
pack the structures below.
And second, the following is a userspace API structures, so it needs to
be in its own file in include/uapi/linux, along with any supporting
things that users will need to use. And your userspace code should be
using that file.
> +struct ssif_msg {
> + u8 len;
Just to be 100% safe, it might be better to use a u16 on this. The spec
sort of limits this to 255 bytes, but it also sort of leaves it open to
be larger.
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
> --
> 2.35.1
>
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-23 1:51 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-04-23 1:51 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, Joel Stanley,
openipmi-developer, Open Source Submission, linux-arm-kernel,
linux-i2c
On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
This is much better, the handling of lengths and indexes is much easier
to understand. I hope you agree.
I may be repeating myself on some things, it's been a while since the
last submit. So please forgive me if I do.
Comments inline...
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
Shouldn't this be <=? If you were sending something that was exactly 94
bytes, for instance, you should have a 32-byte start, a 31-byte middle,
and a 31-byte end. If you don't have <= here, you would have a start, two
31-byte middles, and a zero-length end, which is forbidden by the spec.
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
Should be >= 0 here? If not, (PEC maybe?) you should document why,
because it raises red flags.
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
Spacing issue here. You need to run patches through checkpatch.pl
before submitting them. Also, the empty lines here and above are
inconsistent with the rest of the file.
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
Again, the <= is not normal for this check. If it's correct, it needs
to be documented.
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
Is there any value in having a separate .h file for this? Unless you
want to share something with the IPMI host side, which might make sense
on some of the message numbers, but not a big deal, and even then you
could put the .h file with the .c files.
Except for the userspace API, which I will address later.
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
I seem to remember mentioning this before, but there is no reason to
pack the structures below.
And second, the following is a userspace API structures, so it needs to
be in its own file in include/uapi/linux, along with any supporting
things that users will need to use. And your userspace code should be
using that file.
> +struct ssif_msg {
> + u8 len;
Just to be 100% safe, it might be better to use a u16 on this. The spec
sort of limits this to 255 bytes, but it also sort of leaves it open to
be larger.
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
> --
> 2.35.1
>
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-04-23 1:51 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-04-23 1:51 UTC (permalink / raw)
To: Quan Nguyen
Cc: Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
> in-band IPMI communication with their host in management (BMC) side.
>
> Thanks Dan for the copy_from_user() fix in the link below.
This is much better, the handling of lengths and indexes is much easier
to understand. I hope you agree.
I may be repeating myself on some things, it's been a while since the
last submit. So please forgive me if I do.
Comments inline...
>
> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Remove unneccessary del_timer() in response_timeout() [Corey]
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
> + Solve possible issue if both response timer and ssif_bmc_write()
> occurred at the same time [Corey]
> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
> + Refactor and introduce ssif_part_buffer struct to replace the
> response_buf to manage each send/receive part of ssif [Quan]
> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
> + Support abort feature to skip the current bad request/response and
> wait until next new request [Corey]
> + Refactor the PEC calculation to avoid the re-calculate the PEC on
> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
> + Fix the use of error-proned idx [Corey]
> + Defer the test for valid SMBus command until the read/write part
> is determined [Quan]
> + Change/split unsupported_smbus_cmd() to
> supported_[write|read]_cmd() [Corey]
> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>
> v6:
> + Drop the use of slave_enable() [Wolfram]
> + Make i2c-aspeed to issue RxCmdLast command on all
> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
> + Make i2c slave to return -EBUSY when it's busy [Quan]
> + Drop the aborting feature as return Completion Code 0xFF may stop
> host to retry and make ipmi_ssif.so fails to load [Quan]
> + Add timer to recover slave from busy state when no response [Quan]
> + Clean request/response buffer appropriately [Quan]
> + Add some minor change on error and warning messages [Quan]
>
> v5:
> + None
>
> v4:
> + Send response with Completion code 0xFF when aborting [Quan]
> + Added bounding check on SMBus writes and the whole request [Dan]
> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
> corruption if somehow buffer is written past the end [Dan]
> + Return -EINVAL if userspace buffer too small, dont
> silence truncate [Corey, Joel]
> + Not necessary to check NONBLOCK in lock [Corey]
> + Enforce one user at a time [Joel]
> + Reject write with invalid response length from userspace [Corey]
> + Add state machines for better ssif bmc state handling [Quan]
> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
> SSIF BMC driver [Quan]
> + Change compatible string "aspeed,ast2500-ssif-bmc" to
> "ampere,ssif-bmc" [Quan]
> + Abort current request with invalid SMBus write or
> invalid command [Quan]
> + Abort all request if there is pending response [Quan]
> + Changed validate_pec() to validate_request() [Quan]
> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
> + Print internal state string for ease investigating issue [Quan]
> + Move to READY state on SLAVE_STOP event [Quan]
> + Change initilize_transfer() to process_smbus_cmd() [Quan]
> + Introduce functions for each slave event [Quan]
>
> v3:
> + Removed redundant license info [Joel]
> + Switched to use traditional if-else [Joel]
> + Removed unused ssif_bmc_ioctl() [Joel]
> + Made handle_request()/complete_response() to return void [Joel]
> + Refactored send_ssif_bmc_response() and
> receive_ssif_bmc_request() [Corey]
> + Removed mutex [Corey]
> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
> + Removed the unnecessary memset [Corey]
> + Switch to use dev_err() [Corey]
>
> v2:
> + Fixed compiling error with COMPILE_TEST for arc
>
> drivers/char/ipmi/Kconfig | 11 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
> drivers/char/ipmi/ssif_bmc.h | 107 +++++
> 4 files changed, 899 insertions(+)
> create mode 100644 drivers/char/ipmi/ssif_bmc.c
> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index b061e6b513ed..18a89093d64e 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
> found on Aspeed SOCs (AST2400 and AST2500). The driver
> implements the BMC side of the BT interface.
>
> +config SSIF_IPMI_BMC
> + tristate "SSIF IPMI BMC driver"
> + select I2C
> + select I2C_SLAVE
> + help
> + This enables the IPMI SMBus system interface (SSIF) at the
> + management (BMC) side.
> +
> + The driver implements the BMC side of the SMBus system
> + interface (SSIF).
> +
> config IPMB_DEVICE_INTERFACE
> tristate 'IPMB Interface handler'
> depends on I2C
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 7ce790efad92..cb6138b8ded9 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> new file mode 100644
> index 000000000000..4cff5e1a075e
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -0,0 +1,780 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +
> +#include "ssif_bmc.h"
> +
> +static const char *state_to_string(enum ssif_state state)
> +{
> + switch (state) {
> + case SSIF_READY:
> + return "SSIF_READY";
> + case SSIF_START:
> + return "SSIF_START";
> + case SSIF_SMBUS_CMD:
> + return "SSIF_SMBUS_CMD";
> + case SSIF_REQ_RECVING:
> + return "SSIF_REQ_RECVING";
> + case SSIF_RES_SENDING:
> + return "SSIF_RES_SENDING";
> + case SSIF_ABORTING:
> + return "SSIF_ABORTING";
> + default:
> + return "SSIF_STATE_UNKNOWN";
> + }
> +}
> +
> +/* Handle SSIF message that will be sent to user */
> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (!ssif_bmc->request_available) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + ssif_bmc->request_available);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + ret = -EINVAL;
> + } else {
> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
> + memcpy(&msg, &ssif_bmc->request, count);
> + ssif_bmc->request_available = false;
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + ret = copy_to_user(buf, &msg, count);
> + }
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +/* Handle SSIF message that is written by user */
> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + struct ssif_msg msg;
> + unsigned long flags;
> + ssize_t ret;
> +
> + if (count > sizeof(struct ssif_msg))
> + return -EINVAL;
> +
> + if (copy_from_user(&msg, buf, count))
> + return -EFAULT;
> +
> + if (!msg.len || count < msg.len + 1)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + while (ssif_bmc->response_in_progress) {
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
> + !ssif_bmc->response_in_progress);
> + if (ret)
> + return ret;
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> + }
> +
> + /*
> + * The write must complete before the response timeout fired, otherwise
> + * the response is aborted and wait for next request
> + * Return -EINVAL if the response is aborted
> + */
> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
> + if (ret)
> + goto exit;
> +
> + del_timer(&ssif_bmc->response_timer);
> + ssif_bmc->response_timer_inited = false;
> +
> + memcpy(&ssif_bmc->response, &msg, count);
> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
> +
> + ssif_bmc->response_in_progress = true;
> +
> + /* ssif_bmc not busy */
> + ssif_bmc->busy = false;
> +
> + /* Clean old request buffer */
> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
> +exit:
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return (ret < 0) ? ret : count;
> +}
> +
> +static int ssif_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + int ret = 0;
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + if (!ssif_bmc->running)
> + ssif_bmc->running = 1;
> + else
> + ret = -EBUSY;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return ret;
> +}
> +
> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> + __poll_t mask = 0;
> +
> + poll_wait(file, &ssif_bmc->wait_queue, wait);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + /* The request is available, userspace application can get the request */
> + if (ssif_bmc->request_available)
> + mask |= POLLIN;
> +
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return mask;
> +}
> +
> +static int ssif_bmc_release(struct inode *inode, struct file *file)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
> +
> + spin_lock_irq(&ssif_bmc->lock);
> + ssif_bmc->running = 0;
> + spin_unlock_irq(&ssif_bmc->lock);
> +
> + return 0;
> +}
> +
> +/*
> + * System calls to device interface for user apps
> + */
> +static const struct file_operations ssif_bmc_fops = {
> + .owner = THIS_MODULE,
> + .open = ssif_bmc_open,
> + .read = ssif_bmc_read,
> + .write = ssif_bmc_write,
> + .release = ssif_bmc_release,
> + .poll = ssif_bmc_poll,
> +};
> +
> +/* Called with ssif_bmc->lock held. */
> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* Invalidate response in buffer to denote it having been sent. */
> + ssif_bmc->response.len = 0;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->remain_len = 0;
> + ssif_bmc->busy = false;
> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
> + wake_up_all(&ssif_bmc->wait_queue);
> +}
> +
> +static void response_timeout(struct timer_list *t)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + /* Do nothing if the response is in progress */
> + if (!ssif_bmc->response_in_progress) {
> + /* Recover ssif_bmc from busy */
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> + /* Set aborting flag */
> + ssif_bmc->aborting = true;
> + }
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +}
> +
> +/* Called with ssif_bmc->lock held. */
> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + /* set ssif_bmc to busy waiting for response */
> + ssif_bmc->busy = true;
> + /* Request message is available to process */
> + ssif_bmc->request_available = true;
> + /* Clean old response buffer */
> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
> + /* This is the new READ request.*/
> + wake_up_all(&ssif_bmc->wait_queue);
> +
> + /* Armed timer to recover slave from busy state in case of no response */
> + if (!ssif_bmc->response_timer_inited) {
> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
> + ssif_bmc->response_timer_inited = true;
> + }
> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
> +}
> +
> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
> +{
> + u8 addr = part->address;
> +
> + /* PEC - Start Read Address */
> + part->pec = i2c_smbus_pec(0, &addr, 1);
> + /* PEC - SSIF Command */
> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
> + /* PEC - Restart Write Address */
> + addr = addr | 0x01;
> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
> + if (part->length)
> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
> +}
> +
> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + part->length = ssif_bmc->response.len;
> +
> + /* Clear the rest to 0 */
> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
> +}
> +
> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + u8 part_len = 0;
> +
> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_MULTIPART_READ_START:
> + /*
> + * Read Start length is 32 bytes.
> + * Read Start transfer first 30 bytes of IPMI response
> + * and 2 special code 0x00, 0x01.
> + */
> + ssif_bmc->nbytes_processed = 0;
> + ssif_bmc->block_num = 0;
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
> +
> + part->payload[0] = 0x00; /* Start Flag */
> + part->payload[1] = 0x01; /* Start Flag */
> +
> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
> + break;
> +
> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
> + /*
> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
> + * IPMI data plus block number byte.
> + */
> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
Shouldn't this be <=? If you were sending something that was exactly 94
bytes, for instance, you should have a 32-byte start, a 31-byte middle,
and a 31-byte end. If you don't have <= here, you would have a start, two
31-byte middles, and a zero-length end, which is forbidden by the spec.
> + /*
> + * This is READ End message
> + * Return length is the remaining response data length
> + * plus block number
> + * Block number 0xFF is to indicate this is last message
> + *
> + */
> + /* Clean the buffer */
> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
> + part->length = ssif_bmc->remain_len + 1;
> + part_len = ssif_bmc->remain_len;
> + ssif_bmc->block_num = 0xFF;
> + part->payload[0] = ssif_bmc->block_num;
> + } else {
> + /*
> + * This is READ Middle message
> + * Response length is the maximum SMBUS transfer length
> + * Block number byte is incremented
> + * Return length is maximum SMBUS transfer length
> + */
> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
> + part->payload[0] = ssif_bmc->block_num;
> + ssif_bmc->block_num++;
> + }
> +
> + ssif_bmc->remain_len -= part_len;
> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
> + part_len);
> + break;
> +
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +
> + ssif_bmc->nbytes_processed += part_len;
> +}
> +
> +static bool supported_read_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
> + return true;
> +
> + return false;
> +}
> +
> +static bool supported_write_cmd(u8 cmd)
> +{
> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + return true;
> +
> + return false;
> +}
> +
> +/* Process the IPMI response that will be read by master */
> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + /* msg_idx start from 0 */
> + if (part->index < part->length)
> + *val = part->payload[part->index];
> + else if (part->index == part->length && ssif_bmc->pec_support)
> + *val = part->pec;
> + else
> + *val = 0;
> +
> + part->index++;
> +}
> +
> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* msg_idx should not be 0 when reach here */
> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
Should be >= 0 here? If not, (PEC maybe?) you should document why,
because it raises red flags.
> + return;
> +
> + if (ssif_bmc->msg_idx == 1) {
> + ssif_bmc->part_buf.length = *val;
> + ssif_bmc->part_buf.index = 0;
> + } else {
> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
> + }
> +
> + ssif_bmc->msg_idx++;
> +}
> +
> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> + bool ret = true;
> + u8 cpec;
> + u8 addr;
> +
> + if (part->index == part->length) {
> + /* PEC is not included */
> + ssif_bmc->pec_support = false;
> + ret = true;
> + goto exit;
> + }
> +
> + if (part->index != part->length + 1) {
> + ret = false;
> + goto exit;
> + }
> +
> + /* PEC is included */
> + ssif_bmc->pec_support = true;
> + part->pec = part->payload[part->length];
> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
> + cpec = i2c_smbus_pec(0, &addr, 1);
> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
> + /*
> + * As SMBus specification does not allow the length
> + * (byte count) in the Write-Block protocol to be zero.
> + * Therefore, it is illegal to have the last Middle
> + * transaction in the sequence carry 32-byte and have
> + * a length of ‘0’ in the End transaction.
> + * But some users may try to use this way and we should
> + * prevent ssif_bmc driver broken in this case.
> + */
> + if (part->length)
> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
> +
> + if (cpec != part->pec)
> + ret = false;
> +
> +exit:
> + return ret;
> +}
> +
> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
> +{
> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
> +
> + switch (part->smbus_cmd) {
> + case SSIF_IPMI_SINGLEPART_WRITE:
> + /* save the whole part to request*/
> + ssif_bmc->request.len = part->length;
> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
> +
> + break;
> + case SSIF_IPMI_MULTIPART_WRITE_START:
> + ssif_bmc->request.len = 0;
Spacing issue here. You need to run patches through checkpatch.pl
before submitting them. Also, the empty lines here and above are
inconsistent with the rest of the file.
> +
> + fallthrough;
> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
> + case SSIF_IPMI_MULTIPART_WRITE_END:
> + /* Do the bound check here, not allow the request len exceed 254 bytes */
> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
Again, the <= is not normal for this check. If it's correct, it needs
to be documented.
> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
> + part->payload, part->length);
> + ssif_bmc->request.len += part->length;
> + } else {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: Request exceeded 254 bytes, aborting");
> + /* Request too long, aborting */
> + ssif_bmc->aborting = true;
> + }
> + break;
> + default:
> + /* Do not expect to go to this case */
> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
> + __func__, part->smbus_cmd);
> + break;
> + }
> +}
> +
> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + /* SMBUS command can vary (single or multi-part) */
> + ssif_bmc->part_buf.smbus_cmd = *val;
> + ssif_bmc->msg_idx = 1;
> +
> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
> + /*
> + * The response maybe not come in-time, causing host SSIF driver
> + * to timeout and resend a new request. In such case check for
> + * pending response and clear it
> + */
> + if (ssif_bmc->response_in_progress)
> + complete_response(ssif_bmc);
> +
> + /* This is new request, flip aborting flag if set */
> + if (ssif_bmc->aborting)
> + ssif_bmc->aborting = false;
> + }
> +}
> +
> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_RES_SENDING;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + if (ssif_bmc->is_singlepart_read)
> + set_singlepart_response_buffer(ssif_bmc);
> + else
> + set_multipart_response_buffer(ssif_bmc);
> +
> + calculate_response_part_pec(&ssif_bmc->part_buf);
> + ssif_bmc->part_buf.index = 0;
> + *val = ssif_bmc->part_buf.length;
> +}
> +
> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_SMBUS_CMD) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + *val = 0;
> + return;
> + }
> +
> + /* Send 0 if there is nothing to send */
> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
> + *val = 0;
> + return;
> + }
> +
> + handle_read_processed(ssif_bmc, val);
> +}
> +
> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
> + ssif_bmc->state = SSIF_START;
> +
> + } else if (ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_REQ_RECVING ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> + return;
> + }
> +
> + ssif_bmc->msg_idx = 0;
> + ssif_bmc->part_buf.address = *val;
> +}
> +
> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_RES_SENDING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_ABORTING;
> +
> + } else if (ssif_bmc->state == SSIF_START) {
> + ssif_bmc->state = SSIF_SMBUS_CMD;
> +
> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
> + ssif_bmc->part_buf.smbus_cmd);
> + ssif_bmc->aborting = true;
> + }
> +
> + if (ssif_bmc->aborting)
> + ssif_bmc->state = SSIF_ABORTING;
> + else
> + ssif_bmc->state = SSIF_REQ_RECVING;
> + }
> +
> + /* This is response sending state */
> + if (ssif_bmc->state == SSIF_REQ_RECVING)
> + handle_write_received(ssif_bmc, val);
> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
> + process_smbus_cmd(ssif_bmc, val);
> +}
> +
> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
> +{
> + if (ssif_bmc->state == SSIF_READY ||
> + ssif_bmc->state == SSIF_START ||
> + ssif_bmc->state == SSIF_SMBUS_CMD ||
> + ssif_bmc->state == SSIF_ABORTING) {
> + dev_warn(&ssif_bmc->client->dev,
> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
> + __func__, state_to_string(ssif_bmc->state));
> + ssif_bmc->state = SSIF_READY;
> +
> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
> + if (validate_request_part(ssif_bmc)) {
> + process_request_part(ssif_bmc);
> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
> + handle_request(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + } else {
> + /*
> + * A BMC that receives an invalid request drop the data for the write
> + * transaction and any further transactions (read or write) until
> + * the next valid read or write Start transaction is received
> + */
> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
> + ssif_bmc->aborting = true;
> + }
> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
> + /* Invalidate response buffer to denote it is sent */
> + complete_response(ssif_bmc);
> + ssif_bmc->state = SSIF_READY;
> + }
> +
> + /* Reset message index */
> + ssif_bmc->msg_idx = 0;
> +}
> +
> +/*
> + * Callback function to handle I2C slave events
> + */
> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
> +{
> + unsigned long flags;
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> + int ret = 0;
> +
> + spin_lock_irqsave(&ssif_bmc->lock, flags);
> +
> + switch (event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + on_read_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + on_write_requested_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_READ_PROCESSED:
> + on_read_processed_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_WRITE_RECEIVED:
> + on_write_received_event(ssif_bmc, val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + on_stop_event(ssif_bmc, val);
> + break;
> +
> + default:
> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
> + break;
> + }
> +
> + if (!ssif_bmc->aborting && ssif_bmc->busy)
> + ret = -EBUSY;
> +
> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
> +
> + return ret;
> +}
> +
> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> + struct ssif_bmc_ctx *ssif_bmc;
> + int ret;
> +
> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
> + if (!ssif_bmc)
> + return -ENOMEM;
> +
> + spin_lock_init(&ssif_bmc->lock);
> +
> + init_waitqueue_head(&ssif_bmc->wait_queue);
> + ssif_bmc->request_available = false;
> + ssif_bmc->response_in_progress = false;
> + ssif_bmc->busy = false;
> + ssif_bmc->response_timer_inited = false;
> +
> + /* Register misc device interface */
> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> + ssif_bmc->miscdev.name = DEVICE_NAME;
> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
> + ssif_bmc->miscdev.parent = &client->dev;
> + ret = misc_register(&ssif_bmc->miscdev);
> + if (ret)
> + goto out;
> +
> + ssif_bmc->client = client;
> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
> +
> + /* Register I2C slave */
> + i2c_set_clientdata(client, ssif_bmc);
> + ret = i2c_slave_register(client, ssif_bmc_cb);
> + if (ret) {
> + misc_deregister(&ssif_bmc->miscdev);
> + goto out;
> + }
> +
> + return 0;
> +out:
> + devm_kfree(&client->dev, ssif_bmc);
> + return ret;
> +}
> +
> +static int ssif_bmc_remove(struct i2c_client *client)
> +{
> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
> +
> + i2c_slave_unregister(client);
> + misc_deregister(&ssif_bmc->miscdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ssif_bmc_match[] = {
> + { .compatible = "ssif-bmc" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
> +
> +static const struct i2c_device_id ssif_bmc_id[] = {
> + { DEVICE_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
> +
> +static struct i2c_driver ssif_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = ssif_bmc_match,
> + },
> + .probe = ssif_bmc_probe,
> + .remove = ssif_bmc_remove,
> + .id_table = ssif_bmc_id,
> +};
> +
> +module_i2c_driver(ssif_bmc_driver);
> +
> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
> new file mode 100644
> index 000000000000..2c3fc2a4698f
> --- /dev/null
> +++ b/drivers/char/ipmi/ssif_bmc.h
> @@ -0,0 +1,107 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * The driver for BMC side of SSIF interface
> + *
> + * Copyright (c) 2022, Ampere Computing LLC
> + *
> + */
> +#ifndef __SSIF_BMC_H__
> +#define __SSIF_BMC_H__
> +
Is there any value in having a separate .h file for this? Unless you
want to share something with the IPMI host side, which might make sense
on some of the message numbers, but not a big deal, and even then you
could put the .h file with the .c files.
Except for the userspace API, which I will address later.
> +#define DEVICE_NAME "ipmi-ssif-host"
> +
> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
> +
> +/* A standard SMBus Transaction is limited to 32 data bytes */
> +#define MAX_PAYLOAD_PER_TRANSACTION 32
> +/* Transaction includes the address, the command, the length and the PEC byte */
> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
> +
> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
> +
> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
> +#define SSIF_IPMI_SINGLEPART_READ 0x3
> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
> +
> +/* Include netfn and cmd field */
> +#define MSG_PAYLOAD_LEN_MAX 254
> +/*
> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
> + * Recover ssif_bmc from busy state if it takes up to 500ms
> + */
> +#define RESPONSE_TIMEOUT 500 /* ms */
> +
I seem to remember mentioning this before, but there is no reason to
pack the structures below.
And second, the following is a userspace API structures, so it needs to
be in its own file in include/uapi/linux, along with any supporting
things that users will need to use. And your userspace code should be
using that file.
> +struct ssif_msg {
> + u8 len;
Just to be 100% safe, it might be better to use a u16 on this. The spec
sort of limits this to 255 bytes, but it also sort of leaves it open to
be larger.
> + u8 payload[MSG_PAYLOAD_LEN_MAX];
> +} __packed;
> +
> +struct ssif_part_buffer {
> + u8 address;
> + u8 smbus_cmd;
> + u8 length;
> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> + u8 pec;
> + u8 index;
> +} __packed;
> +
> +/*
> + * SSIF internal states:
> + * SSIF_READY 0x00 : Ready state
> + * SSIF_START 0x01 : Start smbus transaction
> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> + * SSIF_REQ_RECVING 0x03 : Receiving request
> + * SSIF_RES_SENDING 0x04 : Sending response
> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> + */
> +enum ssif_state {
> + SSIF_READY,
> + SSIF_START,
> + SSIF_SMBUS_CMD,
> + SSIF_REQ_RECVING,
> + SSIF_RES_SENDING,
> + SSIF_ABORTING,
> + SSIF_STATE_MAX
> +};
> +
> +struct ssif_bmc_ctx {
> + struct i2c_client *client;
> + struct miscdevice miscdev;
> + int msg_idx;
> + bool pec_support;
> + /* ssif bmc spinlock */
> + spinlock_t lock;
> + wait_queue_head_t wait_queue;
> + u8 running;
> + enum ssif_state state;
> + /* Timeout waiting for response */
> + struct timer_list response_timer;
> + bool response_timer_inited;
> + /* Flag to identify a Multi-part Read Transaction */
> + bool is_singlepart_read;
> + u8 nbytes_processed;
> + u8 remain_len;
> + u8 recv_len;
> + /* Block Number of a Multi-part Read Transaction */
> + u8 block_num;
> + bool request_available;
> + bool response_in_progress;
> + bool busy;
> + bool aborting;
> + /* Buffer for SSIF Transaction part*/
> + struct ssif_part_buffer part_buf;
> + struct ssif_msg response;
> + struct ssif_msg request;
> +};
> +
> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> +{
> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> +}
> +#endif /* __SSIF_BMC_H__ */
> --
> 2.35.1
>
>
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^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-04-25 21:39 ` Rob Herring
-1 siblings, 0 replies; 67+ messages in thread
From: Rob Herring @ 2022-04-25 21:39 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, Corey Minyard, linux-aspeed, Krzysztof Kozlowski,
Andrew Jeffery, openbmc, Thang Q . Nguyen, Brendan Higgins,
linux-kernel, Phong Vo, Wolfram Sang, Rob Herring, linux-i2c,
Open Source Submission, openipmi-developer, linux-arm-kernel,
Joel Stanley
On Fri, 22 Apr 2022 11:08:02 +0700, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
Reviewed-by: Rob Herring <robh@kernel.org>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-25 21:39 ` Rob Herring
0 siblings, 0 replies; 67+ messages in thread
From: Rob Herring @ 2022-04-25 21:39 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Krzysztof Kozlowski, linux-i2c, linux-aspeed,
openbmc, devicetree, Wolfram Sang, Open Source Submission,
Thang Q . Nguyen, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, linux-kernel, Rob Herring, Joel Stanley,
linux-arm-kernel, Phong Vo, openipmi-developer
On Fri, 22 Apr 2022 11:08:02 +0700, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
Reviewed-by: Rob Herring <robh@kernel.org>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 2/3] bindings: ipmi: Add binding for SSIF BMC driver
@ 2022-04-25 21:39 ` Rob Herring
0 siblings, 0 replies; 67+ messages in thread
From: Rob Herring @ 2022-04-25 21:39 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Krzysztof Kozlowski, linux-i2c, linux-aspeed,
openbmc, devicetree, Wolfram Sang, Open Source Submission,
Thang Q . Nguyen, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, linux-kernel, Rob Herring, Joel Stanley,
linux-arm-kernel, Phong Vo, openipmi-developer
On Fri, 22 Apr 2022 11:08:02 +0700, Quan Nguyen wrote:
> Add device tree binding document for the SSIF BMC driver.
>
> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> ---
> v7:
> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>
> v6:
> + None
>
> v5:
> + None
>
> v4:
> + Fix warning with dt_binding_check [Rob]
> + Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
>
> v3:
> + Switched to use DT schema format [Rob]
>
> v2:
> + None
>
> .../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
>
Reviewed-by: Rob Herring <robh@kernel.org>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-04-23 1:51 ` Corey Minyard
(?)
@ 2022-05-04 6:45 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-05-04 6:45 UTC (permalink / raw)
To: minyard
Cc: Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
On 23/04/2022 08:51, Corey Minyard wrote:
> On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
>> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
>> in-band IPMI communication with their host in management (BMC) side.
>>
>> Thanks Dan for the copy_from_user() fix in the link below.
>
> This is much better, the handling of lengths and indexes is much easier
> to understand. I hope you agree.
>
> I may be repeating myself on some things, it's been a while since the
> last submit. So please forgive me if I do.
>
Thank you, Corey.
Please do. I dont know how to express my thanks but without your comment
the code will not get better.
> Comments inline...
>
>>
>> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
>> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
>> ---
>> v7:
>> + Remove unneccessary del_timer() in response_timeout() [Corey]
>> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
>> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
>> + Solve possible issue if both response timer and ssif_bmc_write()
>> occurred at the same time [Corey]
>> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
>> + Refactor and introduce ssif_part_buffer struct to replace the
>> response_buf to manage each send/receive part of ssif [Quan]
>> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
>> + Support abort feature to skip the current bad request/response and
>> wait until next new request [Corey]
>> + Refactor the PEC calculation to avoid the re-calculate the PEC on
>> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
>> + Fix the use of error-proned idx [Corey]
>> + Defer the test for valid SMBus command until the read/write part
>> is determined [Quan]
>> + Change/split unsupported_smbus_cmd() to
>> supported_[write|read]_cmd() [Corey]
>> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>>
>> v6:
>> + Drop the use of slave_enable() [Wolfram]
>> + Make i2c-aspeed to issue RxCmdLast command on all
>> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
>> + Make i2c slave to return -EBUSY when it's busy [Quan]
>> + Drop the aborting feature as return Completion Code 0xFF may stop
>> host to retry and make ipmi_ssif.so fails to load [Quan]
>> + Add timer to recover slave from busy state when no response [Quan]
>> + Clean request/response buffer appropriately [Quan]
>> + Add some minor change on error and warning messages [Quan]
>>
>> v5:
>> + None
>>
>> v4:
>> + Send response with Completion code 0xFF when aborting [Quan]
>> + Added bounding check on SMBus writes and the whole request [Dan]
>> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
>> corruption if somehow buffer is written past the end [Dan]
>> + Return -EINVAL if userspace buffer too small, dont
>> silence truncate [Corey, Joel]
>> + Not necessary to check NONBLOCK in lock [Corey]
>> + Enforce one user at a time [Joel]
>> + Reject write with invalid response length from userspace [Corey]
>> + Add state machines for better ssif bmc state handling [Quan]
>> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
>> SSIF BMC driver [Quan]
>> + Change compatible string "aspeed,ast2500-ssif-bmc" to
>> "ampere,ssif-bmc" [Quan]
>> + Abort current request with invalid SMBus write or
>> invalid command [Quan]
>> + Abort all request if there is pending response [Quan]
>> + Changed validate_pec() to validate_request() [Quan]
>> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
>> + Print internal state string for ease investigating issue [Quan]
>> + Move to READY state on SLAVE_STOP event [Quan]
>> + Change initilize_transfer() to process_smbus_cmd() [Quan]
>> + Introduce functions for each slave event [Quan]
>>
>> v3:
>> + Removed redundant license info [Joel]
>> + Switched to use traditional if-else [Joel]
>> + Removed unused ssif_bmc_ioctl() [Joel]
>> + Made handle_request()/complete_response() to return void [Joel]
>> + Refactored send_ssif_bmc_response() and
>> receive_ssif_bmc_request() [Corey]
>> + Removed mutex [Corey]
>> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
>> + Removed the unnecessary memset [Corey]
>> + Switch to use dev_err() [Corey]
>>
>> v2:
>> + Fixed compiling error with COMPILE_TEST for arc
>>
>> drivers/char/ipmi/Kconfig | 11 +
>> drivers/char/ipmi/Makefile | 1 +
>> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
>> drivers/char/ipmi/ssif_bmc.h | 107 +++++
>> 4 files changed, 899 insertions(+)
>> create mode 100644 drivers/char/ipmi/ssif_bmc.c
>> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>>
>> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
>> index b061e6b513ed..18a89093d64e 100644
>> --- a/drivers/char/ipmi/Kconfig
>> +++ b/drivers/char/ipmi/Kconfig
>> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
>> found on Aspeed SOCs (AST2400 and AST2500). The driver
>> implements the BMC side of the BT interface.
>>
>> +config SSIF_IPMI_BMC
>> + tristate "SSIF IPMI BMC driver"
>> + select I2C
>> + select I2C_SLAVE
>> + help
>> + This enables the IPMI SMBus system interface (SSIF) at the
>> + management (BMC) side.
>> +
>> + The driver implements the BMC side of the SMBus system
>> + interface (SSIF).
>> +
>> config IPMB_DEVICE_INTERFACE
>> tristate 'IPMB Interface handler'
>> depends on I2C
>> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
>> index 7ce790efad92..cb6138b8ded9 100644
>> --- a/drivers/char/ipmi/Makefile
>> +++ b/drivers/char/ipmi/Makefile
>> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
>> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
>> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
>> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
>> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
>> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
>> new file mode 100644
>> index 000000000000..4cff5e1a075e
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.c
>> @@ -0,0 +1,780 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/poll.h>
>> +#include <linux/sched.h>
>> +#include <linux/mutex.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/timer.h>
>> +#include <linux/jiffies.h>
>> +
>> +#include "ssif_bmc.h"
>> +
>> +static const char *state_to_string(enum ssif_state state)
>> +{
>> + switch (state) {
>> + case SSIF_READY:
>> + return "SSIF_READY";
>> + case SSIF_START:
>> + return "SSIF_START";
>> + case SSIF_SMBUS_CMD:
>> + return "SSIF_SMBUS_CMD";
>> + case SSIF_REQ_RECVING:
>> + return "SSIF_REQ_RECVING";
>> + case SSIF_RES_SENDING:
>> + return "SSIF_RES_SENDING";
>> + case SSIF_ABORTING:
>> + return "SSIF_ABORTING";
>> + default:
>> + return "SSIF_STATE_UNKNOWN";
>> + }
>> +}
>> +
>> +/* Handle SSIF message that will be sent to user */
>> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (!ssif_bmc->request_available) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + ssif_bmc->request_available);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + ret = -EINVAL;
>> + } else {
>> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
>> + memcpy(&msg, &ssif_bmc->request, count);
>> + ssif_bmc->request_available = false;
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + ret = copy_to_user(buf, &msg, count);
>> + }
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +/* Handle SSIF message that is written by user */
>> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
>> + loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + if (count > sizeof(struct ssif_msg))
>> + return -EINVAL;
>> +
>> + if (copy_from_user(&msg, buf, count))
>> + return -EFAULT;
>> +
>> + if (!msg.len || count < msg.len + 1)
>> + return -EINVAL;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (ssif_bmc->response_in_progress) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + !ssif_bmc->response_in_progress);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + /*
>> + * The write must complete before the response timeout fired, otherwise
>> + * the response is aborted and wait for next request
>> + * Return -EINVAL if the response is aborted
>> + */
>> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
>> + if (ret)
>> + goto exit;
>> +
>> + del_timer(&ssif_bmc->response_timer);
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + memcpy(&ssif_bmc->response, &msg, count);
>> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
>> +
>> + ssif_bmc->response_in_progress = true;
>> +
>> + /* ssif_bmc not busy */
>> + ssif_bmc->busy = false;
>> +
>> + /* Clean old request buffer */
>> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
>> +exit:
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +static int ssif_bmc_open(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + int ret = 0;
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + if (!ssif_bmc->running)
>> + ssif_bmc->running = 1;
>> + else
>> + ret = -EBUSY;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + __poll_t mask = 0;
>> +
>> + poll_wait(file, &ssif_bmc->wait_queue, wait);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + /* The request is available, userspace application can get the request */
>> + if (ssif_bmc->request_available)
>> + mask |= POLLIN;
>> +
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return mask;
>> +}
>> +
>> +static int ssif_bmc_release(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + ssif_bmc->running = 0;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * System calls to device interface for user apps
>> + */
>> +static const struct file_operations ssif_bmc_fops = {
>> + .owner = THIS_MODULE,
>> + .open = ssif_bmc_open,
>> + .read = ssif_bmc_read,
>> + .write = ssif_bmc_write,
>> + .release = ssif_bmc_release,
>> + .poll = ssif_bmc_poll,
>> +};
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* Invalidate response in buffer to denote it having been sent. */
>> + ssif_bmc->response.len = 0;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->remain_len = 0;
>> + ssif_bmc->busy = false;
>> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +}
>> +
>> +static void response_timeout(struct timer_list *t)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + /* Do nothing if the response is in progress */
>> + if (!ssif_bmc->response_in_progress) {
>> + /* Recover ssif_bmc from busy */
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> + /* Set aborting flag */
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +}
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* set ssif_bmc to busy waiting for response */
>> + ssif_bmc->busy = true;
>> + /* Request message is available to process */
>> + ssif_bmc->request_available = true;
>> + /* Clean old response buffer */
>> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
>> + /* This is the new READ request.*/
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +
>> + /* Armed timer to recover slave from busy state in case of no response */
>> + if (!ssif_bmc->response_timer_inited) {
>> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
>> + ssif_bmc->response_timer_inited = true;
>> + }
>> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
>> +}
>> +
>> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
>> +{
>> + u8 addr = part->address;
>> +
>> + /* PEC - Start Read Address */
>> + part->pec = i2c_smbus_pec(0, &addr, 1);
>> + /* PEC - SSIF Command */
>> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
>> + /* PEC - Restart Write Address */
>> + addr = addr | 0x01;
>> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
>> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
>> + if (part->length)
>> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
>> +}
>> +
>> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + part->length = ssif_bmc->response.len;
>> +
>> + /* Clear the rest to 0 */
>> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
>> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
>> +}
>> +
>> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + u8 part_len = 0;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_MULTIPART_READ_START:
>> + /*
>> + * Read Start length is 32 bytes.
>> + * Read Start transfer first 30 bytes of IPMI response
>> + * and 2 special code 0x00, 0x01.
>> + */
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->block_num = 0;
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
>> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
>> +
>> + part->payload[0] = 0x00; /* Start Flag */
>> + part->payload[1] = 0x01; /* Start Flag */
>> +
>> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
>> + break;
>> +
>> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
>> + /*
>> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
>> + * IPMI data plus block number byte.
>> + */
>> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
>
> Shouldn't this be <=? If you were sending something that was exactly 94
> bytes, for instance, you should have a 32-byte start, a 31-byte middle,
> and a 31-byte end. If you don't have <= here, you would have a start, two
> 31-byte middles, and a zero-length end, which is forbidden by the spec.
>
Thank for the comment.
Will fix this in next version.
If so, in "94 bytes" case, we have to assure the end part length is at
least 1 bytes. the last middle in this case must be 30.
>> + /*
>> + * This is READ End message
>> + * Return length is the remaining response data length
>> + * plus block number
>> + * Block number 0xFF is to indicate this is last message
>> + *
>> + */
>> + /* Clean the buffer */
>> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
>> + part->length = ssif_bmc->remain_len + 1;
>> + part_len = ssif_bmc->remain_len;
>> + ssif_bmc->block_num = 0xFF;
>> + part->payload[0] = ssif_bmc->block_num;
>> + } else {
>> + /*
>> + * This is READ Middle message
>> + * Response length is the maximum SMBUS transfer length
>> + * Block number byte is incremented
>> + * Return length is maximum SMBUS transfer length
>> + */
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
>> + part->payload[0] = ssif_bmc->block_num;
>> + ssif_bmc->block_num++;
>> + }
>> +
>> + ssif_bmc->remain_len -= part_len;
>> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
>> + part_len);
>> + break;
>> +
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +
>> + ssif_bmc->nbytes_processed += part_len;
>> +}
>> +
>> +static bool supported_read_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +static bool supported_write_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +/* Process the IPMI response that will be read by master */
>> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + /* msg_idx start from 0 */
>> + if (part->index < part->length)
>> + *val = part->payload[part->index];
>> + else if (part->index == part->length && ssif_bmc->pec_support)
>> + *val = part->pec;
>> + else
>> + *val = 0;
>> +
>> + part->index++;
>> +}
>> +
>> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* msg_idx should not be 0 when reach here */
>> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
>
> Should be >= 0 here? If not, (PEC maybe?) you should document why,
> because it raises red flags.
>
Yes, will fix in next version.
The msg_idx should not be 0 here because it must be at least set to 1 in
process_smbus_cmd() before calling this function.
The MAX_TRANSACTION is 32 bytes payload + 4 bytes for slave address, the
command, the len and the PEC.
So I think it would change to:
if (ssif_bmc->msg_idx >= 0 || ssif_bmc->msg_idx > MAX_TRANSACTION)
>> + return;
>> +
>> + if (ssif_bmc->msg_idx == 1) {
>> + ssif_bmc->part_buf.length = *val;
>> + ssif_bmc->part_buf.index = 0;
>> + } else {
>> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
>> + }
>> +
>> + ssif_bmc->msg_idx++;
>> +}
>> +
>> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + bool ret = true;
>> + u8 cpec;
>> + u8 addr;
>> +
>> + if (part->index == part->length) {
>> + /* PEC is not included */
>> + ssif_bmc->pec_support = false;
>> + ret = true;
>> + goto exit;
>> + }
>> +
>> + if (part->index != part->length + 1) {
>> + ret = false;
>> + goto exit;
>> + }
>> +
>> + /* PEC is included */
>> + ssif_bmc->pec_support = true;
>> + part->pec = part->payload[part->length];
>> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + cpec = i2c_smbus_pec(0, &addr, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
>> + /*
>> + * As SMBus specification does not allow the length
>> + * (byte count) in the Write-Block protocol to be zero.
>> + * Therefore, it is illegal to have the last Middle
>> + * transaction in the sequence carry 32-byte and have
>> + * a length of ‘0’ in the End transaction.
>> + * But some users may try to use this way and we should
>> + * prevent ssif_bmc driver broken in this case.
>> + */
>> + if (part->length)
>> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
>> +
>> + if (cpec != part->pec)
>> + ret = false;
>> +
>> +exit:
>> + return ret;
>> +}
>> +
>> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_SINGLEPART_WRITE:
>> + /* save the whole part to request*/
>> + ssif_bmc->request.len = part->length;
>> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
>> +
>> + break;
>> + case SSIF_IPMI_MULTIPART_WRITE_START:
>> + ssif_bmc->request.len = 0;
>
> Spacing issue here. You need to run patches through checkpatch.pl
> before submitting them. Also, the empty lines here and above are
> inconsistent with the rest of the file.
>
Yes, will fix in next version.
But it was always checked with checkpatch.pl everytime. Dont know why
checkpatch.pl did not catch it.
>> +
>> + fallthrough;
>> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
>> + case SSIF_IPMI_MULTIPART_WRITE_END:
>> + /* Do the bound check here, not allow the request len exceed 254 bytes */
>> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
>
> Again, the <= is not normal for this check. If it's correct, it needs
> to be documented.
>
Will rewrite this part in next version
>> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
>> + part->payload, part->length);
>> + ssif_bmc->request.len += part->length;
>> + } else {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: Request exceeded 254 bytes, aborting");
>> + /* Request too long, aborting */
>> + ssif_bmc->aborting = true;
>> + }
>> + break;
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +}
>> +
>> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* SMBUS command can vary (single or multi-part) */
>> + ssif_bmc->part_buf.smbus_cmd = *val;
>> + ssif_bmc->msg_idx = 1;
>> +
>> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
>> + /*
>> + * The response maybe not come in-time, causing host SSIF driver
>> + * to timeout and resend a new request. In such case check for
>> + * pending response and clear it
>> + */
>> + if (ssif_bmc->response_in_progress)
>> + complete_response(ssif_bmc);
>> +
>> + /* This is new request, flip aborting flag if set */
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->aborting = false;
>> + }
>> +}
>> +
>> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_RES_SENDING;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + if (ssif_bmc->is_singlepart_read)
>> + set_singlepart_response_buffer(ssif_bmc);
>> + else
>> + set_multipart_response_buffer(ssif_bmc);
>> +
>> + calculate_response_part_pec(&ssif_bmc->part_buf);
>> + ssif_bmc->part_buf.index = 0;
>> + *val = ssif_bmc->part_buf.length;
>> +}
>> +
>> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> + }
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + handle_read_processed(ssif_bmc, val);
>> +}
>> +
>> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + ssif_bmc->state = SSIF_START;
>> +
>> + } else if (ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + return;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> + ssif_bmc->part_buf.address = *val;
>> +}
>> +
>> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> +
>> + } else if (ssif_bmc->state == SSIF_START) {
>> + ssif_bmc->state = SSIF_SMBUS_CMD;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_REQ_RECVING;
>> + }
>> +
>> + /* This is response sending state */
>> + if (ssif_bmc->state == SSIF_REQ_RECVING)
>> + handle_write_received(ssif_bmc, val);
>> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
>> + process_smbus_cmd(ssif_bmc, val);
>> +}
>> +
>> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD ||
>> + ssif_bmc->state == SSIF_ABORTING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_READY;
>> +
>> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
>> + if (validate_request_part(ssif_bmc)) {
>> + process_request_part(ssif_bmc);
>> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + handle_request(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + } else {
>> + /*
>> + * A BMC that receives an invalid request drop the data for the write
>> + * transaction and any further transactions (read or write) until
>> + * the next valid read or write Start transaction is received
>> + */
>> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
>> + ssif_bmc->aborting = true;
>> + }
>> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
>> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
>> + /* Invalidate response buffer to denote it is sent */
>> + complete_response(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + }
>> +
>> + /* Reset message index */
>> + ssif_bmc->msg_idx = 0;
>> +}
>> +
>> +/*
>> + * Callback function to handle I2C slave events
>> + */
>> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
>> +{
>> + unsigned long flags;
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> + int ret = 0;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + switch (event) {
>> + case I2C_SLAVE_READ_REQUESTED:
>> + on_read_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_REQUESTED:
>> + on_write_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_READ_PROCESSED:
>> + on_read_processed_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_RECEIVED:
>> + on_write_received_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_STOP:
>> + on_stop_event(ssif_bmc, val);
>> + break;
>> +
>> + default:
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
>> + break;
>> + }
>> +
>> + if (!ssif_bmc->aborting && ssif_bmc->busy)
>> + ret = -EBUSY;
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc;
>> + int ret;
>> +
>> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
>> + if (!ssif_bmc)
>> + return -ENOMEM;
>> +
>> + spin_lock_init(&ssif_bmc->lock);
>> +
>> + init_waitqueue_head(&ssif_bmc->wait_queue);
>> + ssif_bmc->request_available = false;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + /* Register misc device interface */
>> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
>> + ssif_bmc->miscdev.name = DEVICE_NAME;
>> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
>> + ssif_bmc->miscdev.parent = &client->dev;
>> + ret = misc_register(&ssif_bmc->miscdev);
>> + if (ret)
>> + goto out;
>> +
>> + ssif_bmc->client = client;
>> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
>> +
>> + /* Register I2C slave */
>> + i2c_set_clientdata(client, ssif_bmc);
>> + ret = i2c_slave_register(client, ssif_bmc_cb);
>> + if (ret) {
>> + misc_deregister(&ssif_bmc->miscdev);
>> + goto out;
>> + }
>> +
>> + return 0;
>> +out:
>> + devm_kfree(&client->dev, ssif_bmc);
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_remove(struct i2c_client *client)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> +
>> + i2c_slave_unregister(client);
>> + misc_deregister(&ssif_bmc->miscdev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id ssif_bmc_match[] = {
>> + { .compatible = "ssif-bmc" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
>> +
>> +static const struct i2c_device_id ssif_bmc_id[] = {
>> + { DEVICE_NAME, 0 },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
>> +
>> +static struct i2c_driver ssif_bmc_driver = {
>> + .driver = {
>> + .name = DEVICE_NAME,
>> + .of_match_table = ssif_bmc_match,
>> + },
>> + .probe = ssif_bmc_probe,
>> + .remove = ssif_bmc_remove,
>> + .id_table = ssif_bmc_id,
>> +};
>> +
>> +module_i2c_driver(ssif_bmc_driver);
>> +
>> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
>> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
>> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
>> new file mode 100644
>> index 000000000000..2c3fc2a4698f
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.h
>> @@ -0,0 +1,107 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +#ifndef __SSIF_BMC_H__
>> +#define __SSIF_BMC_H__
>> +
>
> Is there any value in having a separate .h file for this? Unless you
> want to share something with the IPMI host side, which might make sense
> on some of the message numbers, but not a big deal, and even then you
> could put the .h file with the .c files.
>
> Except for the userspace API, which I will address later.
>
So far, there is no benefit to have separate .h file. So it will be
merged into one single .c file in next version.
>> +#define DEVICE_NAME "ipmi-ssif-host"
>> +
>> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
>> +
>> +/* A standard SMBus Transaction is limited to 32 data bytes */
>> +#define MAX_PAYLOAD_PER_TRANSACTION 32
>> +/* Transaction includes the address, the command, the length and the PEC byte */
>> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
>> +
>> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
>> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
>> +
>> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
>> +#define SSIF_IPMI_SINGLEPART_READ 0x3
>> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
>> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
>> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
>> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
>> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
>> +
>> +/* Include netfn and cmd field */
>> +#define MSG_PAYLOAD_LEN_MAX 254
>> +/*
>> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
>> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
>> + * Recover ssif_bmc from busy state if it takes up to 500ms
>> + */
>> +#define RESPONSE_TIMEOUT 500 /* ms */
>> +
>
> I seem to remember mentioning this before, but there is no reason to
> pack the structures below.
>
The packed structure is because we want to pick the len directly from
user space without worry about the padding byte.
As we plan not to use the .h file in next version, I still would like to
use packed structure internally inside ssif_bmc.c file.
> And second, the following is a userspace API structures, so it needs to
> be in its own file in include/uapi/linux, along with any supporting
> things that users will need to use. And your userspace code should be
> using that file.
>
Meantime, I'd like not to use .h as I see there is no demand for sharing
the data structure between kernel and user space yet. But we may do it
in the future.
>> +struct ssif_msg {
>> + u8 len;
>
> Just to be 100% safe, it might be better to use a u16 on this. The spec
> sort of limits this to 255 bytes, but it also sort of leaves it open to
> be larger.
>
Yes, u8 only limited to 255 bytes and there is no space for future grow.
>> + u8 payload[MSG_PAYLOAD_LEN_MAX];
>> +} __packed;
>> +
>> +struct ssif_part_buffer {
>> + u8 address;
>> + u8 smbus_cmd;
>> + u8 length;
>> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
>> + u8 pec;
>> + u8 index;
>> +} __packed;
>> +
>> +/*
>> + * SSIF internal states:
>> + * SSIF_READY 0x00 : Ready state
>> + * SSIF_START 0x01 : Start smbus transaction
>> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
>> + * SSIF_REQ_RECVING 0x03 : Receiving request
>> + * SSIF_RES_SENDING 0x04 : Sending response
>> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
>> + */
>> +enum ssif_state {
>> + SSIF_READY,
>> + SSIF_START,
>> + SSIF_SMBUS_CMD,
>> + SSIF_REQ_RECVING,
>> + SSIF_RES_SENDING,
>> + SSIF_ABORTING,
>> + SSIF_STATE_MAX
>> +};
>> +
>> +struct ssif_bmc_ctx {
>> + struct i2c_client *client;
>> + struct miscdevice miscdev;
>> + int msg_idx;
>> + bool pec_support;
>> + /* ssif bmc spinlock */
>> + spinlock_t lock;
>> + wait_queue_head_t wait_queue;
>> + u8 running;
>> + enum ssif_state state;
>> + /* Timeout waiting for response */
>> + struct timer_list response_timer;
>> + bool response_timer_inited;
>> + /* Flag to identify a Multi-part Read Transaction */
>> + bool is_singlepart_read;
>> + u8 nbytes_processed;
>> + u8 remain_len;
>> + u8 recv_len;
>> + /* Block Number of a Multi-part Read Transaction */
>> + u8 block_num;
>> + bool request_available;
>> + bool response_in_progress;
>> + bool busy;
>> + bool aborting;
>> + /* Buffer for SSIF Transaction part*/
>> + struct ssif_part_buffer part_buf;
>> + struct ssif_msg response;
>> + struct ssif_msg request;
>> +};
>> +
>> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
>> +{
>> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
>> +}
>> +#endif /* __SSIF_BMC_H__ */
>> --
>> 2.35.1
>>
>>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-05-04 6:45 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-05-04 6:45 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, Joel Stanley,
openipmi-developer, Open Source Submission, linux-arm-kernel,
linux-i2c
On 23/04/2022 08:51, Corey Minyard wrote:
> On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
>> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
>> in-band IPMI communication with their host in management (BMC) side.
>>
>> Thanks Dan for the copy_from_user() fix in the link below.
>
> This is much better, the handling of lengths and indexes is much easier
> to understand. I hope you agree.
>
> I may be repeating myself on some things, it's been a while since the
> last submit. So please forgive me if I do.
>
Thank you, Corey.
Please do. I dont know how to express my thanks but without your comment
the code will not get better.
> Comments inline...
>
>>
>> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
>> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
>> ---
>> v7:
>> + Remove unneccessary del_timer() in response_timeout() [Corey]
>> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
>> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
>> + Solve possible issue if both response timer and ssif_bmc_write()
>> occurred at the same time [Corey]
>> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
>> + Refactor and introduce ssif_part_buffer struct to replace the
>> response_buf to manage each send/receive part of ssif [Quan]
>> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
>> + Support abort feature to skip the current bad request/response and
>> wait until next new request [Corey]
>> + Refactor the PEC calculation to avoid the re-calculate the PEC on
>> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
>> + Fix the use of error-proned idx [Corey]
>> + Defer the test for valid SMBus command until the read/write part
>> is determined [Quan]
>> + Change/split unsupported_smbus_cmd() to
>> supported_[write|read]_cmd() [Corey]
>> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>>
>> v6:
>> + Drop the use of slave_enable() [Wolfram]
>> + Make i2c-aspeed to issue RxCmdLast command on all
>> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
>> + Make i2c slave to return -EBUSY when it's busy [Quan]
>> + Drop the aborting feature as return Completion Code 0xFF may stop
>> host to retry and make ipmi_ssif.so fails to load [Quan]
>> + Add timer to recover slave from busy state when no response [Quan]
>> + Clean request/response buffer appropriately [Quan]
>> + Add some minor change on error and warning messages [Quan]
>>
>> v5:
>> + None
>>
>> v4:
>> + Send response with Completion code 0xFF when aborting [Quan]
>> + Added bounding check on SMBus writes and the whole request [Dan]
>> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
>> corruption if somehow buffer is written past the end [Dan]
>> + Return -EINVAL if userspace buffer too small, dont
>> silence truncate [Corey, Joel]
>> + Not necessary to check NONBLOCK in lock [Corey]
>> + Enforce one user at a time [Joel]
>> + Reject write with invalid response length from userspace [Corey]
>> + Add state machines for better ssif bmc state handling [Quan]
>> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
>> SSIF BMC driver [Quan]
>> + Change compatible string "aspeed,ast2500-ssif-bmc" to
>> "ampere,ssif-bmc" [Quan]
>> + Abort current request with invalid SMBus write or
>> invalid command [Quan]
>> + Abort all request if there is pending response [Quan]
>> + Changed validate_pec() to validate_request() [Quan]
>> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
>> + Print internal state string for ease investigating issue [Quan]
>> + Move to READY state on SLAVE_STOP event [Quan]
>> + Change initilize_transfer() to process_smbus_cmd() [Quan]
>> + Introduce functions for each slave event [Quan]
>>
>> v3:
>> + Removed redundant license info [Joel]
>> + Switched to use traditional if-else [Joel]
>> + Removed unused ssif_bmc_ioctl() [Joel]
>> + Made handle_request()/complete_response() to return void [Joel]
>> + Refactored send_ssif_bmc_response() and
>> receive_ssif_bmc_request() [Corey]
>> + Removed mutex [Corey]
>> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
>> + Removed the unnecessary memset [Corey]
>> + Switch to use dev_err() [Corey]
>>
>> v2:
>> + Fixed compiling error with COMPILE_TEST for arc
>>
>> drivers/char/ipmi/Kconfig | 11 +
>> drivers/char/ipmi/Makefile | 1 +
>> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
>> drivers/char/ipmi/ssif_bmc.h | 107 +++++
>> 4 files changed, 899 insertions(+)
>> create mode 100644 drivers/char/ipmi/ssif_bmc.c
>> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>>
>> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
>> index b061e6b513ed..18a89093d64e 100644
>> --- a/drivers/char/ipmi/Kconfig
>> +++ b/drivers/char/ipmi/Kconfig
>> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
>> found on Aspeed SOCs (AST2400 and AST2500). The driver
>> implements the BMC side of the BT interface.
>>
>> +config SSIF_IPMI_BMC
>> + tristate "SSIF IPMI BMC driver"
>> + select I2C
>> + select I2C_SLAVE
>> + help
>> + This enables the IPMI SMBus system interface (SSIF) at the
>> + management (BMC) side.
>> +
>> + The driver implements the BMC side of the SMBus system
>> + interface (SSIF).
>> +
>> config IPMB_DEVICE_INTERFACE
>> tristate 'IPMB Interface handler'
>> depends on I2C
>> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
>> index 7ce790efad92..cb6138b8ded9 100644
>> --- a/drivers/char/ipmi/Makefile
>> +++ b/drivers/char/ipmi/Makefile
>> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
>> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
>> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
>> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
>> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
>> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
>> new file mode 100644
>> index 000000000000..4cff5e1a075e
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.c
>> @@ -0,0 +1,780 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/poll.h>
>> +#include <linux/sched.h>
>> +#include <linux/mutex.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/timer.h>
>> +#include <linux/jiffies.h>
>> +
>> +#include "ssif_bmc.h"
>> +
>> +static const char *state_to_string(enum ssif_state state)
>> +{
>> + switch (state) {
>> + case SSIF_READY:
>> + return "SSIF_READY";
>> + case SSIF_START:
>> + return "SSIF_START";
>> + case SSIF_SMBUS_CMD:
>> + return "SSIF_SMBUS_CMD";
>> + case SSIF_REQ_RECVING:
>> + return "SSIF_REQ_RECVING";
>> + case SSIF_RES_SENDING:
>> + return "SSIF_RES_SENDING";
>> + case SSIF_ABORTING:
>> + return "SSIF_ABORTING";
>> + default:
>> + return "SSIF_STATE_UNKNOWN";
>> + }
>> +}
>> +
>> +/* Handle SSIF message that will be sent to user */
>> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (!ssif_bmc->request_available) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + ssif_bmc->request_available);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + ret = -EINVAL;
>> + } else {
>> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
>> + memcpy(&msg, &ssif_bmc->request, count);
>> + ssif_bmc->request_available = false;
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + ret = copy_to_user(buf, &msg, count);
>> + }
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +/* Handle SSIF message that is written by user */
>> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
>> + loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + if (count > sizeof(struct ssif_msg))
>> + return -EINVAL;
>> +
>> + if (copy_from_user(&msg, buf, count))
>> + return -EFAULT;
>> +
>> + if (!msg.len || count < msg.len + 1)
>> + return -EINVAL;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (ssif_bmc->response_in_progress) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + !ssif_bmc->response_in_progress);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + /*
>> + * The write must complete before the response timeout fired, otherwise
>> + * the response is aborted and wait for next request
>> + * Return -EINVAL if the response is aborted
>> + */
>> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
>> + if (ret)
>> + goto exit;
>> +
>> + del_timer(&ssif_bmc->response_timer);
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + memcpy(&ssif_bmc->response, &msg, count);
>> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
>> +
>> + ssif_bmc->response_in_progress = true;
>> +
>> + /* ssif_bmc not busy */
>> + ssif_bmc->busy = false;
>> +
>> + /* Clean old request buffer */
>> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
>> +exit:
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +static int ssif_bmc_open(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + int ret = 0;
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + if (!ssif_bmc->running)
>> + ssif_bmc->running = 1;
>> + else
>> + ret = -EBUSY;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + __poll_t mask = 0;
>> +
>> + poll_wait(file, &ssif_bmc->wait_queue, wait);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + /* The request is available, userspace application can get the request */
>> + if (ssif_bmc->request_available)
>> + mask |= POLLIN;
>> +
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return mask;
>> +}
>> +
>> +static int ssif_bmc_release(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + ssif_bmc->running = 0;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * System calls to device interface for user apps
>> + */
>> +static const struct file_operations ssif_bmc_fops = {
>> + .owner = THIS_MODULE,
>> + .open = ssif_bmc_open,
>> + .read = ssif_bmc_read,
>> + .write = ssif_bmc_write,
>> + .release = ssif_bmc_release,
>> + .poll = ssif_bmc_poll,
>> +};
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* Invalidate response in buffer to denote it having been sent. */
>> + ssif_bmc->response.len = 0;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->remain_len = 0;
>> + ssif_bmc->busy = false;
>> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +}
>> +
>> +static void response_timeout(struct timer_list *t)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + /* Do nothing if the response is in progress */
>> + if (!ssif_bmc->response_in_progress) {
>> + /* Recover ssif_bmc from busy */
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> + /* Set aborting flag */
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +}
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* set ssif_bmc to busy waiting for response */
>> + ssif_bmc->busy = true;
>> + /* Request message is available to process */
>> + ssif_bmc->request_available = true;
>> + /* Clean old response buffer */
>> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
>> + /* This is the new READ request.*/
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +
>> + /* Armed timer to recover slave from busy state in case of no response */
>> + if (!ssif_bmc->response_timer_inited) {
>> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
>> + ssif_bmc->response_timer_inited = true;
>> + }
>> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
>> +}
>> +
>> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
>> +{
>> + u8 addr = part->address;
>> +
>> + /* PEC - Start Read Address */
>> + part->pec = i2c_smbus_pec(0, &addr, 1);
>> + /* PEC - SSIF Command */
>> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
>> + /* PEC - Restart Write Address */
>> + addr = addr | 0x01;
>> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
>> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
>> + if (part->length)
>> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
>> +}
>> +
>> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + part->length = ssif_bmc->response.len;
>> +
>> + /* Clear the rest to 0 */
>> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
>> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
>> +}
>> +
>> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + u8 part_len = 0;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_MULTIPART_READ_START:
>> + /*
>> + * Read Start length is 32 bytes.
>> + * Read Start transfer first 30 bytes of IPMI response
>> + * and 2 special code 0x00, 0x01.
>> + */
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->block_num = 0;
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
>> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
>> +
>> + part->payload[0] = 0x00; /* Start Flag */
>> + part->payload[1] = 0x01; /* Start Flag */
>> +
>> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
>> + break;
>> +
>> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
>> + /*
>> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
>> + * IPMI data plus block number byte.
>> + */
>> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
>
> Shouldn't this be <=? If you were sending something that was exactly 94
> bytes, for instance, you should have a 32-byte start, a 31-byte middle,
> and a 31-byte end. If you don't have <= here, you would have a start, two
> 31-byte middles, and a zero-length end, which is forbidden by the spec.
>
Thank for the comment.
Will fix this in next version.
If so, in "94 bytes" case, we have to assure the end part length is at
least 1 bytes. the last middle in this case must be 30.
>> + /*
>> + * This is READ End message
>> + * Return length is the remaining response data length
>> + * plus block number
>> + * Block number 0xFF is to indicate this is last message
>> + *
>> + */
>> + /* Clean the buffer */
>> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
>> + part->length = ssif_bmc->remain_len + 1;
>> + part_len = ssif_bmc->remain_len;
>> + ssif_bmc->block_num = 0xFF;
>> + part->payload[0] = ssif_bmc->block_num;
>> + } else {
>> + /*
>> + * This is READ Middle message
>> + * Response length is the maximum SMBUS transfer length
>> + * Block number byte is incremented
>> + * Return length is maximum SMBUS transfer length
>> + */
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
>> + part->payload[0] = ssif_bmc->block_num;
>> + ssif_bmc->block_num++;
>> + }
>> +
>> + ssif_bmc->remain_len -= part_len;
>> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
>> + part_len);
>> + break;
>> +
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +
>> + ssif_bmc->nbytes_processed += part_len;
>> +}
>> +
>> +static bool supported_read_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +static bool supported_write_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +/* Process the IPMI response that will be read by master */
>> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + /* msg_idx start from 0 */
>> + if (part->index < part->length)
>> + *val = part->payload[part->index];
>> + else if (part->index == part->length && ssif_bmc->pec_support)
>> + *val = part->pec;
>> + else
>> + *val = 0;
>> +
>> + part->index++;
>> +}
>> +
>> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* msg_idx should not be 0 when reach here */
>> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
>
> Should be >= 0 here? If not, (PEC maybe?) you should document why,
> because it raises red flags.
>
Yes, will fix in next version.
The msg_idx should not be 0 here because it must be at least set to 1 in
process_smbus_cmd() before calling this function.
The MAX_TRANSACTION is 32 bytes payload + 4 bytes for slave address, the
command, the len and the PEC.
So I think it would change to:
if (ssif_bmc->msg_idx >= 0 || ssif_bmc->msg_idx > MAX_TRANSACTION)
>> + return;
>> +
>> + if (ssif_bmc->msg_idx == 1) {
>> + ssif_bmc->part_buf.length = *val;
>> + ssif_bmc->part_buf.index = 0;
>> + } else {
>> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
>> + }
>> +
>> + ssif_bmc->msg_idx++;
>> +}
>> +
>> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + bool ret = true;
>> + u8 cpec;
>> + u8 addr;
>> +
>> + if (part->index == part->length) {
>> + /* PEC is not included */
>> + ssif_bmc->pec_support = false;
>> + ret = true;
>> + goto exit;
>> + }
>> +
>> + if (part->index != part->length + 1) {
>> + ret = false;
>> + goto exit;
>> + }
>> +
>> + /* PEC is included */
>> + ssif_bmc->pec_support = true;
>> + part->pec = part->payload[part->length];
>> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + cpec = i2c_smbus_pec(0, &addr, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
>> + /*
>> + * As SMBus specification does not allow the length
>> + * (byte count) in the Write-Block protocol to be zero.
>> + * Therefore, it is illegal to have the last Middle
>> + * transaction in the sequence carry 32-byte and have
>> + * a length of ‘0’ in the End transaction.
>> + * But some users may try to use this way and we should
>> + * prevent ssif_bmc driver broken in this case.
>> + */
>> + if (part->length)
>> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
>> +
>> + if (cpec != part->pec)
>> + ret = false;
>> +
>> +exit:
>> + return ret;
>> +}
>> +
>> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_SINGLEPART_WRITE:
>> + /* save the whole part to request*/
>> + ssif_bmc->request.len = part->length;
>> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
>> +
>> + break;
>> + case SSIF_IPMI_MULTIPART_WRITE_START:
>> + ssif_bmc->request.len = 0;
>
> Spacing issue here. You need to run patches through checkpatch.pl
> before submitting them. Also, the empty lines here and above are
> inconsistent with the rest of the file.
>
Yes, will fix in next version.
But it was always checked with checkpatch.pl everytime. Dont know why
checkpatch.pl did not catch it.
>> +
>> + fallthrough;
>> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
>> + case SSIF_IPMI_MULTIPART_WRITE_END:
>> + /* Do the bound check here, not allow the request len exceed 254 bytes */
>> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
>
> Again, the <= is not normal for this check. If it's correct, it needs
> to be documented.
>
Will rewrite this part in next version
>> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
>> + part->payload, part->length);
>> + ssif_bmc->request.len += part->length;
>> + } else {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: Request exceeded 254 bytes, aborting");
>> + /* Request too long, aborting */
>> + ssif_bmc->aborting = true;
>> + }
>> + break;
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +}
>> +
>> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* SMBUS command can vary (single or multi-part) */
>> + ssif_bmc->part_buf.smbus_cmd = *val;
>> + ssif_bmc->msg_idx = 1;
>> +
>> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
>> + /*
>> + * The response maybe not come in-time, causing host SSIF driver
>> + * to timeout and resend a new request. In such case check for
>> + * pending response and clear it
>> + */
>> + if (ssif_bmc->response_in_progress)
>> + complete_response(ssif_bmc);
>> +
>> + /* This is new request, flip aborting flag if set */
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->aborting = false;
>> + }
>> +}
>> +
>> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_RES_SENDING;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + if (ssif_bmc->is_singlepart_read)
>> + set_singlepart_response_buffer(ssif_bmc);
>> + else
>> + set_multipart_response_buffer(ssif_bmc);
>> +
>> + calculate_response_part_pec(&ssif_bmc->part_buf);
>> + ssif_bmc->part_buf.index = 0;
>> + *val = ssif_bmc->part_buf.length;
>> +}
>> +
>> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> + }
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + handle_read_processed(ssif_bmc, val);
>> +}
>> +
>> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + ssif_bmc->state = SSIF_START;
>> +
>> + } else if (ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + return;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> + ssif_bmc->part_buf.address = *val;
>> +}
>> +
>> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> +
>> + } else if (ssif_bmc->state == SSIF_START) {
>> + ssif_bmc->state = SSIF_SMBUS_CMD;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_REQ_RECVING;
>> + }
>> +
>> + /* This is response sending state */
>> + if (ssif_bmc->state == SSIF_REQ_RECVING)
>> + handle_write_received(ssif_bmc, val);
>> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
>> + process_smbus_cmd(ssif_bmc, val);
>> +}
>> +
>> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD ||
>> + ssif_bmc->state == SSIF_ABORTING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_READY;
>> +
>> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
>> + if (validate_request_part(ssif_bmc)) {
>> + process_request_part(ssif_bmc);
>> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + handle_request(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + } else {
>> + /*
>> + * A BMC that receives an invalid request drop the data for the write
>> + * transaction and any further transactions (read or write) until
>> + * the next valid read or write Start transaction is received
>> + */
>> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
>> + ssif_bmc->aborting = true;
>> + }
>> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
>> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
>> + /* Invalidate response buffer to denote it is sent */
>> + complete_response(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + }
>> +
>> + /* Reset message index */
>> + ssif_bmc->msg_idx = 0;
>> +}
>> +
>> +/*
>> + * Callback function to handle I2C slave events
>> + */
>> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
>> +{
>> + unsigned long flags;
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> + int ret = 0;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + switch (event) {
>> + case I2C_SLAVE_READ_REQUESTED:
>> + on_read_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_REQUESTED:
>> + on_write_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_READ_PROCESSED:
>> + on_read_processed_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_RECEIVED:
>> + on_write_received_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_STOP:
>> + on_stop_event(ssif_bmc, val);
>> + break;
>> +
>> + default:
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
>> + break;
>> + }
>> +
>> + if (!ssif_bmc->aborting && ssif_bmc->busy)
>> + ret = -EBUSY;
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc;
>> + int ret;
>> +
>> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
>> + if (!ssif_bmc)
>> + return -ENOMEM;
>> +
>> + spin_lock_init(&ssif_bmc->lock);
>> +
>> + init_waitqueue_head(&ssif_bmc->wait_queue);
>> + ssif_bmc->request_available = false;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + /* Register misc device interface */
>> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
>> + ssif_bmc->miscdev.name = DEVICE_NAME;
>> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
>> + ssif_bmc->miscdev.parent = &client->dev;
>> + ret = misc_register(&ssif_bmc->miscdev);
>> + if (ret)
>> + goto out;
>> +
>> + ssif_bmc->client = client;
>> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
>> +
>> + /* Register I2C slave */
>> + i2c_set_clientdata(client, ssif_bmc);
>> + ret = i2c_slave_register(client, ssif_bmc_cb);
>> + if (ret) {
>> + misc_deregister(&ssif_bmc->miscdev);
>> + goto out;
>> + }
>> +
>> + return 0;
>> +out:
>> + devm_kfree(&client->dev, ssif_bmc);
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_remove(struct i2c_client *client)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> +
>> + i2c_slave_unregister(client);
>> + misc_deregister(&ssif_bmc->miscdev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id ssif_bmc_match[] = {
>> + { .compatible = "ssif-bmc" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
>> +
>> +static const struct i2c_device_id ssif_bmc_id[] = {
>> + { DEVICE_NAME, 0 },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
>> +
>> +static struct i2c_driver ssif_bmc_driver = {
>> + .driver = {
>> + .name = DEVICE_NAME,
>> + .of_match_table = ssif_bmc_match,
>> + },
>> + .probe = ssif_bmc_probe,
>> + .remove = ssif_bmc_remove,
>> + .id_table = ssif_bmc_id,
>> +};
>> +
>> +module_i2c_driver(ssif_bmc_driver);
>> +
>> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
>> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
>> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
>> new file mode 100644
>> index 000000000000..2c3fc2a4698f
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.h
>> @@ -0,0 +1,107 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +#ifndef __SSIF_BMC_H__
>> +#define __SSIF_BMC_H__
>> +
>
> Is there any value in having a separate .h file for this? Unless you
> want to share something with the IPMI host side, which might make sense
> on some of the message numbers, but not a big deal, and even then you
> could put the .h file with the .c files.
>
> Except for the userspace API, which I will address later.
>
So far, there is no benefit to have separate .h file. So it will be
merged into one single .c file in next version.
>> +#define DEVICE_NAME "ipmi-ssif-host"
>> +
>> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
>> +
>> +/* A standard SMBus Transaction is limited to 32 data bytes */
>> +#define MAX_PAYLOAD_PER_TRANSACTION 32
>> +/* Transaction includes the address, the command, the length and the PEC byte */
>> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
>> +
>> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
>> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
>> +
>> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
>> +#define SSIF_IPMI_SINGLEPART_READ 0x3
>> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
>> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
>> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
>> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
>> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
>> +
>> +/* Include netfn and cmd field */
>> +#define MSG_PAYLOAD_LEN_MAX 254
>> +/*
>> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
>> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
>> + * Recover ssif_bmc from busy state if it takes up to 500ms
>> + */
>> +#define RESPONSE_TIMEOUT 500 /* ms */
>> +
>
> I seem to remember mentioning this before, but there is no reason to
> pack the structures below.
>
The packed structure is because we want to pick the len directly from
user space without worry about the padding byte.
As we plan not to use the .h file in next version, I still would like to
use packed structure internally inside ssif_bmc.c file.
> And second, the following is a userspace API structures, so it needs to
> be in its own file in include/uapi/linux, along with any supporting
> things that users will need to use. And your userspace code should be
> using that file.
>
Meantime, I'd like not to use .h as I see there is no demand for sharing
the data structure between kernel and user space yet. But we may do it
in the future.
>> +struct ssif_msg {
>> + u8 len;
>
> Just to be 100% safe, it might be better to use a u16 on this. The spec
> sort of limits this to 255 bytes, but it also sort of leaves it open to
> be larger.
>
Yes, u8 only limited to 255 bytes and there is no space for future grow.
>> + u8 payload[MSG_PAYLOAD_LEN_MAX];
>> +} __packed;
>> +
>> +struct ssif_part_buffer {
>> + u8 address;
>> + u8 smbus_cmd;
>> + u8 length;
>> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
>> + u8 pec;
>> + u8 index;
>> +} __packed;
>> +
>> +/*
>> + * SSIF internal states:
>> + * SSIF_READY 0x00 : Ready state
>> + * SSIF_START 0x01 : Start smbus transaction
>> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
>> + * SSIF_REQ_RECVING 0x03 : Receiving request
>> + * SSIF_RES_SENDING 0x04 : Sending response
>> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
>> + */
>> +enum ssif_state {
>> + SSIF_READY,
>> + SSIF_START,
>> + SSIF_SMBUS_CMD,
>> + SSIF_REQ_RECVING,
>> + SSIF_RES_SENDING,
>> + SSIF_ABORTING,
>> + SSIF_STATE_MAX
>> +};
>> +
>> +struct ssif_bmc_ctx {
>> + struct i2c_client *client;
>> + struct miscdevice miscdev;
>> + int msg_idx;
>> + bool pec_support;
>> + /* ssif bmc spinlock */
>> + spinlock_t lock;
>> + wait_queue_head_t wait_queue;
>> + u8 running;
>> + enum ssif_state state;
>> + /* Timeout waiting for response */
>> + struct timer_list response_timer;
>> + bool response_timer_inited;
>> + /* Flag to identify a Multi-part Read Transaction */
>> + bool is_singlepart_read;
>> + u8 nbytes_processed;
>> + u8 remain_len;
>> + u8 recv_len;
>> + /* Block Number of a Multi-part Read Transaction */
>> + u8 block_num;
>> + bool request_available;
>> + bool response_in_progress;
>> + bool busy;
>> + bool aborting;
>> + /* Buffer for SSIF Transaction part*/
>> + struct ssif_part_buffer part_buf;
>> + struct ssif_msg response;
>> + struct ssif_msg request;
>> +};
>> +
>> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
>> +{
>> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
>> +}
>> +#endif /* __SSIF_BMC_H__ */
>> --
>> 2.35.1
>>
>>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-05-04 6:45 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-05-04 6:45 UTC (permalink / raw)
To: minyard
Cc: Rob Herring, Krzysztof Kozlowski, Joel Stanley, Andrew Jeffery,
Brendan Higgins, Benjamin Herrenschmidt, Wolfram Sang,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
On 23/04/2022 08:51, Corey Minyard wrote:
> On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote:
>> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
>> in-band IPMI communication with their host in management (BMC) side.
>>
>> Thanks Dan for the copy_from_user() fix in the link below.
>
> This is much better, the handling of lengths and indexes is much easier
> to understand. I hope you agree.
>
> I may be repeating myself on some things, it's been a while since the
> last submit. So please forgive me if I do.
>
Thank you, Corey.
Please do. I dont know how to express my thanks but without your comment
the code will not get better.
> Comments inline...
>
>>
>> Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
>> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
>> ---
>> v7:
>> + Remove unneccessary del_timer() in response_timeout() [Corey]
>> + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
>> + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae]
>> + Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
>> + Solve possible issue if both response timer and ssif_bmc_write()
>> occurred at the same time [Corey]
>> + Fix wrong return type of ssif_bmc_poll() [kernel robot test]
>> + Refactor and introduce ssif_part_buffer struct to replace the
>> response_buf to manage each send/receive part of ssif [Quan]
>> + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
>> + Support abort feature to skip the current bad request/response and
>> wait until next new request [Corey]
>> + Refactor the PEC calculation to avoid the re-calculate the PEC on
>> each I2C_SLAVE_WRITE_RECEIVED event [Quan]
>> + Fix the use of error-proned idx [Corey]
>> + Defer the test for valid SMBus command until the read/write part
>> is determined [Quan]
>> + Change/split unsupported_smbus_cmd() to
>> supported_[write|read]_cmd() [Corey]
>> + Abort the request if somehow its size exceeded 255 bytes [Quan]
>>
>> v6:
>> + Drop the use of slave_enable() [Wolfram]
>> + Make i2c-aspeed to issue RxCmdLast command on all
>> I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
>> + Make i2c slave to return -EBUSY when it's busy [Quan]
>> + Drop the aborting feature as return Completion Code 0xFF may stop
>> host to retry and make ipmi_ssif.so fails to load [Quan]
>> + Add timer to recover slave from busy state when no response [Quan]
>> + Clean request/response buffer appropriately [Quan]
>> + Add some minor change on error and warning messages [Quan]
>>
>> v5:
>> + None
>>
>> v4:
>> + Send response with Completion code 0xFF when aborting [Quan]
>> + Added bounding check on SMBus writes and the whole request [Dan]
>> + Moved buffer to end of struct ssif_bmc_ctx to avoid context
>> corruption if somehow buffer is written past the end [Dan]
>> + Return -EINVAL if userspace buffer too small, dont
>> silence truncate [Corey, Joel]
>> + Not necessary to check NONBLOCK in lock [Corey]
>> + Enforce one user at a time [Joel]
>> + Reject write with invalid response length from userspace [Corey]
>> + Add state machines for better ssif bmc state handling [Quan]
>> + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
>> SSIF BMC driver [Quan]
>> + Change compatible string "aspeed,ast2500-ssif-bmc" to
>> "ampere,ssif-bmc" [Quan]
>> + Abort current request with invalid SMBus write or
>> invalid command [Quan]
>> + Abort all request if there is pending response [Quan]
>> + Changed validate_pec() to validate_request() [Quan]
>> + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
>> + Print internal state string for ease investigating issue [Quan]
>> + Move to READY state on SLAVE_STOP event [Quan]
>> + Change initilize_transfer() to process_smbus_cmd() [Quan]
>> + Introduce functions for each slave event [Quan]
>>
>> v3:
>> + Removed redundant license info [Joel]
>> + Switched to use traditional if-else [Joel]
>> + Removed unused ssif_bmc_ioctl() [Joel]
>> + Made handle_request()/complete_response() to return void [Joel]
>> + Refactored send_ssif_bmc_response() and
>> receive_ssif_bmc_request() [Corey]
>> + Removed mutex [Corey]
>> + Use spin_lock/unlock_irqsave/restore in callback [Corey]
>> + Removed the unnecessary memset [Corey]
>> + Switch to use dev_err() [Corey]
>>
>> v2:
>> + Fixed compiling error with COMPILE_TEST for arc
>>
>> drivers/char/ipmi/Kconfig | 11 +
>> drivers/char/ipmi/Makefile | 1 +
>> drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++
>> drivers/char/ipmi/ssif_bmc.h | 107 +++++
>> 4 files changed, 899 insertions(+)
>> create mode 100644 drivers/char/ipmi/ssif_bmc.c
>> create mode 100644 drivers/char/ipmi/ssif_bmc.h
>>
>> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
>> index b061e6b513ed..18a89093d64e 100644
>> --- a/drivers/char/ipmi/Kconfig
>> +++ b/drivers/char/ipmi/Kconfig
>> @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC
>> found on Aspeed SOCs (AST2400 and AST2500). The driver
>> implements the BMC side of the BT interface.
>>
>> +config SSIF_IPMI_BMC
>> + tristate "SSIF IPMI BMC driver"
>> + select I2C
>> + select I2C_SLAVE
>> + help
>> + This enables the IPMI SMBus system interface (SSIF) at the
>> + management (BMC) side.
>> +
>> + The driver implements the BMC side of the SMBus system
>> + interface (SSIF).
>> +
>> config IPMB_DEVICE_INTERFACE
>> tristate 'IPMB Interface handler'
>> depends on I2C
>> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
>> index 7ce790efad92..cb6138b8ded9 100644
>> --- a/drivers/char/ipmi/Makefile
>> +++ b/drivers/char/ipmi/Makefile
>> @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
>> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
>> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
>> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o
>> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o
>> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
>> new file mode 100644
>> index 000000000000..4cff5e1a075e
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.c
>> @@ -0,0 +1,780 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/poll.h>
>> +#include <linux/sched.h>
>> +#include <linux/mutex.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/timer.h>
>> +#include <linux/jiffies.h>
>> +
>> +#include "ssif_bmc.h"
>> +
>> +static const char *state_to_string(enum ssif_state state)
>> +{
>> + switch (state) {
>> + case SSIF_READY:
>> + return "SSIF_READY";
>> + case SSIF_START:
>> + return "SSIF_START";
>> + case SSIF_SMBUS_CMD:
>> + return "SSIF_SMBUS_CMD";
>> + case SSIF_REQ_RECVING:
>> + return "SSIF_REQ_RECVING";
>> + case SSIF_RES_SENDING:
>> + return "SSIF_RES_SENDING";
>> + case SSIF_ABORTING:
>> + return "SSIF_ABORTING";
>> + default:
>> + return "SSIF_STATE_UNKNOWN";
>> + }
>> +}
>> +
>> +/* Handle SSIF message that will be sent to user */
>> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (!ssif_bmc->request_available) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + ssif_bmc->request_available);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + ret = -EINVAL;
>> + } else {
>> + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg));
>> + memcpy(&msg, &ssif_bmc->request, count);
>> + ssif_bmc->request_available = false;
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + ret = copy_to_user(buf, &msg, count);
>> + }
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +/* Handle SSIF message that is written by user */
>> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
>> + loff_t *ppos)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + struct ssif_msg msg;
>> + unsigned long flags;
>> + ssize_t ret;
>> +
>> + if (count > sizeof(struct ssif_msg))
>> + return -EINVAL;
>> +
>> + if (copy_from_user(&msg, buf, count))
>> + return -EFAULT;
>> +
>> + if (!msg.len || count < msg.len + 1)
>> + return -EINVAL;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + while (ssif_bmc->response_in_progress) {
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> + if (file->f_flags & O_NONBLOCK)
>> + return -EAGAIN;
>> + ret = wait_event_interruptible(ssif_bmc->wait_queue,
>> + !ssif_bmc->response_in_progress);
>> + if (ret)
>> + return ret;
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> + }
>> +
>> + /*
>> + * The write must complete before the response timeout fired, otherwise
>> + * the response is aborted and wait for next request
>> + * Return -EINVAL if the response is aborted
>> + */
>> + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
>> + if (ret)
>> + goto exit;
>> +
>> + del_timer(&ssif_bmc->response_timer);
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + memcpy(&ssif_bmc->response, &msg, count);
>> + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
>> +
>> + ssif_bmc->response_in_progress = true;
>> +
>> + /* ssif_bmc not busy */
>> + ssif_bmc->busy = false;
>> +
>> + /* Clean old request buffer */
>> + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg));
>> +exit:
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return (ret < 0) ? ret : count;
>> +}
>> +
>> +static int ssif_bmc_open(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + int ret = 0;
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + if (!ssif_bmc->running)
>> + ssif_bmc->running = 1;
>> + else
>> + ret = -EBUSY;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> + __poll_t mask = 0;
>> +
>> + poll_wait(file, &ssif_bmc->wait_queue, wait);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + /* The request is available, userspace application can get the request */
>> + if (ssif_bmc->request_available)
>> + mask |= POLLIN;
>> +
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return mask;
>> +}
>> +
>> +static int ssif_bmc_release(struct inode *inode, struct file *file)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
>> +
>> + spin_lock_irq(&ssif_bmc->lock);
>> + ssif_bmc->running = 0;
>> + spin_unlock_irq(&ssif_bmc->lock);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * System calls to device interface for user apps
>> + */
>> +static const struct file_operations ssif_bmc_fops = {
>> + .owner = THIS_MODULE,
>> + .open = ssif_bmc_open,
>> + .read = ssif_bmc_read,
>> + .write = ssif_bmc_write,
>> + .release = ssif_bmc_release,
>> + .poll = ssif_bmc_poll,
>> +};
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* Invalidate response in buffer to denote it having been sent. */
>> + ssif_bmc->response.len = 0;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->remain_len = 0;
>> + ssif_bmc->busy = false;
>> + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +}
>> +
>> +static void response_timeout(struct timer_list *t)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + /* Do nothing if the response is in progress */
>> + if (!ssif_bmc->response_in_progress) {
>> + /* Recover ssif_bmc from busy */
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> + /* Set aborting flag */
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +}
>> +
>> +/* Called with ssif_bmc->lock held. */
>> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + /* set ssif_bmc to busy waiting for response */
>> + ssif_bmc->busy = true;
>> + /* Request message is available to process */
>> + ssif_bmc->request_available = true;
>> + /* Clean old response buffer */
>> + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg));
>> + /* This is the new READ request.*/
>> + wake_up_all(&ssif_bmc->wait_queue);
>> +
>> + /* Armed timer to recover slave from busy state in case of no response */
>> + if (!ssif_bmc->response_timer_inited) {
>> + timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
>> + ssif_bmc->response_timer_inited = true;
>> + }
>> + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
>> +}
>> +
>> +static void calculate_response_part_pec(struct ssif_part_buffer *part)
>> +{
>> + u8 addr = part->address;
>> +
>> + /* PEC - Start Read Address */
>> + part->pec = i2c_smbus_pec(0, &addr, 1);
>> + /* PEC - SSIF Command */
>> + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
>> + /* PEC - Restart Write Address */
>> + addr = addr | 0x01;
>> + part->pec = i2c_smbus_pec(part->pec, &addr, 1);
>> + part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
>> + if (part->length)
>> + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
>> +}
>> +
>> +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + part->length = ssif_bmc->response.len;
>> +
>> + /* Clear the rest to 0 */
>> + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
>> + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
>> +}
>> +
>> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + u8 part_len = 0;
>> +
>> + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_MULTIPART_READ_START:
>> + /*
>> + * Read Start length is 32 bytes.
>> + * Read Start transfer first 30 bytes of IPMI response
>> + * and 2 special code 0x00, 0x01.
>> + */
>> + ssif_bmc->nbytes_processed = 0;
>> + ssif_bmc->block_num = 0;
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
>> + ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
>> +
>> + part->payload[0] = 0x00; /* Start Flag */
>> + part->payload[1] = 0x01; /* Start Flag */
>> +
>> + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
>> + break;
>> +
>> + case SSIF_IPMI_MULTIPART_READ_MIDDLE:
>> + /*
>> + * IPMI READ Middle or READ End messages can carry up to 31 bytes
>> + * IPMI data plus block number byte.
>> + */
>> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
>
> Shouldn't this be <=? If you were sending something that was exactly 94
> bytes, for instance, you should have a 32-byte start, a 31-byte middle,
> and a 31-byte end. If you don't have <= here, you would have a start, two
> 31-byte middles, and a zero-length end, which is forbidden by the spec.
>
Thank for the comment.
Will fix this in next version.
If so, in "94 bytes" case, we have to assure the end part length is at
least 1 bytes. the last middle in this case must be 30.
>> + /*
>> + * This is READ End message
>> + * Return length is the remaining response data length
>> + * plus block number
>> + * Block number 0xFF is to indicate this is last message
>> + *
>> + */
>> + /* Clean the buffer */
>> + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
>> + part->length = ssif_bmc->remain_len + 1;
>> + part_len = ssif_bmc->remain_len;
>> + ssif_bmc->block_num = 0xFF;
>> + part->payload[0] = ssif_bmc->block_num;
>> + } else {
>> + /*
>> + * This is READ Middle message
>> + * Response length is the maximum SMBUS transfer length
>> + * Block number byte is incremented
>> + * Return length is maximum SMBUS transfer length
>> + */
>> + part->length = MAX_PAYLOAD_PER_TRANSACTION;
>> + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
>> + part->payload[0] = ssif_bmc->block_num;
>> + ssif_bmc->block_num++;
>> + }
>> +
>> + ssif_bmc->remain_len -= part_len;
>> + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
>> + part_len);
>> + break;
>> +
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +
>> + ssif_bmc->nbytes_processed += part_len;
>> +}
>> +
>> +static bool supported_read_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_READ ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_START ||
>> + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +static bool supported_write_cmd(u8 cmd)
>> +{
>> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
>> + cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +/* Process the IPMI response that will be read by master */
>> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + /* msg_idx start from 0 */
>> + if (part->index < part->length)
>> + *val = part->payload[part->index];
>> + else if (part->index == part->length && ssif_bmc->pec_support)
>> + *val = part->pec;
>> + else
>> + *val = 0;
>> +
>> + part->index++;
>> +}
>> +
>> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* msg_idx should not be 0 when reach here */
>> + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION)
>
> Should be >= 0 here? If not, (PEC maybe?) you should document why,
> because it raises red flags.
>
Yes, will fix in next version.
The msg_idx should not be 0 here because it must be at least set to 1 in
process_smbus_cmd() before calling this function.
The MAX_TRANSACTION is 32 bytes payload + 4 bytes for slave address, the
command, the len and the PEC.
So I think it would change to:
if (ssif_bmc->msg_idx >= 0 || ssif_bmc->msg_idx > MAX_TRANSACTION)
>> + return;
>> +
>> + if (ssif_bmc->msg_idx == 1) {
>> + ssif_bmc->part_buf.length = *val;
>> + ssif_bmc->part_buf.index = 0;
>> + } else {
>> + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
>> + }
>> +
>> + ssif_bmc->msg_idx++;
>> +}
>> +
>> +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> + bool ret = true;
>> + u8 cpec;
>> + u8 addr;
>> +
>> + if (part->index == part->length) {
>> + /* PEC is not included */
>> + ssif_bmc->pec_support = false;
>> + ret = true;
>> + goto exit;
>> + }
>> +
>> + if (part->index != part->length + 1) {
>> + ret = false;
>> + goto exit;
>> + }
>> +
>> + /* PEC is included */
>> + ssif_bmc->pec_support = true;
>> + part->pec = part->payload[part->length];
>> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
>> + cpec = i2c_smbus_pec(0, &addr, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
>> + cpec = i2c_smbus_pec(cpec, &part->length, 1);
>> + /*
>> + * As SMBus specification does not allow the length
>> + * (byte count) in the Write-Block protocol to be zero.
>> + * Therefore, it is illegal to have the last Middle
>> + * transaction in the sequence carry 32-byte and have
>> + * a length of ‘0’ in the End transaction.
>> + * But some users may try to use this way and we should
>> + * prevent ssif_bmc driver broken in this case.
>> + */
>> + if (part->length)
>> + cpec = i2c_smbus_pec(cpec, part->payload, part->length);
>> +
>> + if (cpec != part->pec)
>> + ret = false;
>> +
>> +exit:
>> + return ret;
>> +}
>> +
>> +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
>> +{
>> + struct ssif_part_buffer *part = &ssif_bmc->part_buf;
>> +
>> + switch (part->smbus_cmd) {
>> + case SSIF_IPMI_SINGLEPART_WRITE:
>> + /* save the whole part to request*/
>> + ssif_bmc->request.len = part->length;
>> + memcpy(ssif_bmc->request.payload, part->payload, part->length);
>> +
>> + break;
>> + case SSIF_IPMI_MULTIPART_WRITE_START:
>> + ssif_bmc->request.len = 0;
>
> Spacing issue here. You need to run patches through checkpatch.pl
> before submitting them. Also, the empty lines here and above are
> inconsistent with the rest of the file.
>
Yes, will fix in next version.
But it was always checked with checkpatch.pl everytime. Dont know why
checkpatch.pl did not catch it.
>> +
>> + fallthrough;
>> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
>> + case SSIF_IPMI_MULTIPART_WRITE_END:
>> + /* Do the bound check here, not allow the request len exceed 254 bytes */
>> + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) {
>
> Again, the <= is not normal for this check. If it's correct, it needs
> to be documented.
>
Will rewrite this part in next version
>> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
>> + part->payload, part->length);
>> + ssif_bmc->request.len += part->length;
>> + } else {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: Request exceeded 254 bytes, aborting");
>> + /* Request too long, aborting */
>> + ssif_bmc->aborting = true;
>> + }
>> + break;
>> + default:
>> + /* Do not expect to go to this case */
>> + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
>> + __func__, part->smbus_cmd);
>> + break;
>> + }
>> +}
>> +
>> +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + /* SMBUS command can vary (single or multi-part) */
>> + ssif_bmc->part_buf.smbus_cmd = *val;
>> + ssif_bmc->msg_idx = 1;
>> +
>> + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
>> + /*
>> + * The response maybe not come in-time, causing host SSIF driver
>> + * to timeout and resend a new request. In such case check for
>> + * pending response and clear it
>> + */
>> + if (ssif_bmc->response_in_progress)
>> + complete_response(ssif_bmc);
>> +
>> + /* This is new request, flip aborting flag if set */
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->aborting = false;
>> + }
>> +}
>> +
>> +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ REQUESTED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_RES_SENDING;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + if (ssif_bmc->is_singlepart_read)
>> + set_singlepart_response_buffer(ssif_bmc);
>> + else
>> + set_multipart_response_buffer(ssif_bmc);
>> +
>> + calculate_response_part_pec(&ssif_bmc->part_buf);
>> + ssif_bmc->part_buf.index = 0;
>> + *val = ssif_bmc->part_buf.length;
>> +}
>> +
>> +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected READ PROCESSED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + *val = 0;
>> + return;
>> + }
>> +
>> + /* Send 0 if there is nothing to send */
>> + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
>> + *val = 0;
>> + return;
>> + }
>> +
>> + handle_read_processed(ssif_bmc, val);
>> +}
>> +
>> +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + ssif_bmc->state = SSIF_START;
>> +
>> + } else if (ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_REQ_RECVING ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE REQUEST in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> + return;
>> + }
>> +
>> + ssif_bmc->msg_idx = 0;
>> + ssif_bmc->part_buf.address = *val;
>> +}
>> +
>> +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_RES_SENDING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_ABORTING;
>> +
>> + } else if (ssif_bmc->state == SSIF_START) {
>> + ssif_bmc->state = SSIF_SMBUS_CMD;
>> +
>> + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
>> + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
>> + ssif_bmc->part_buf.smbus_cmd);
>> + ssif_bmc->aborting = true;
>> + }
>> +
>> + if (ssif_bmc->aborting)
>> + ssif_bmc->state = SSIF_ABORTING;
>> + else
>> + ssif_bmc->state = SSIF_REQ_RECVING;
>> + }
>> +
>> + /* This is response sending state */
>> + if (ssif_bmc->state == SSIF_REQ_RECVING)
>> + handle_write_received(ssif_bmc, val);
>> + else if (ssif_bmc->state == SSIF_SMBUS_CMD)
>> + process_smbus_cmd(ssif_bmc, val);
>> +}
>> +
>> +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
>> +{
>> + if (ssif_bmc->state == SSIF_READY ||
>> + ssif_bmc->state == SSIF_START ||
>> + ssif_bmc->state == SSIF_SMBUS_CMD ||
>> + ssif_bmc->state == SSIF_ABORTING) {
>> + dev_warn(&ssif_bmc->client->dev,
>> + "Warn: %s unexpected SLAVE STOP in state=%s\n",
>> + __func__, state_to_string(ssif_bmc->state));
>> + ssif_bmc->state = SSIF_READY;
>> +
>> + } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
>> + if (validate_request_part(ssif_bmc)) {
>> + process_request_part(ssif_bmc);
>> + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
>> + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
>> + handle_request(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + } else {
>> + /*
>> + * A BMC that receives an invalid request drop the data for the write
>> + * transaction and any further transactions (read or write) until
>> + * the next valid read or write Start transaction is received
>> + */
>> + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
>> + ssif_bmc->aborting = true;
>> + }
>> + } else if (ssif_bmc->state == SSIF_RES_SENDING) {
>> + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
>> + /* Invalidate response buffer to denote it is sent */
>> + complete_response(ssif_bmc);
>> + ssif_bmc->state = SSIF_READY;
>> + }
>> +
>> + /* Reset message index */
>> + ssif_bmc->msg_idx = 0;
>> +}
>> +
>> +/*
>> + * Callback function to handle I2C slave events
>> + */
>> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
>> +{
>> + unsigned long flags;
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> + int ret = 0;
>> +
>> + spin_lock_irqsave(&ssif_bmc->lock, flags);
>> +
>> + switch (event) {
>> + case I2C_SLAVE_READ_REQUESTED:
>> + on_read_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_REQUESTED:
>> + on_write_requested_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_READ_PROCESSED:
>> + on_read_processed_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_WRITE_RECEIVED:
>> + on_write_received_event(ssif_bmc, val);
>> + break;
>> +
>> + case I2C_SLAVE_STOP:
>> + on_stop_event(ssif_bmc, val);
>> + break;
>> +
>> + default:
>> + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
>> + break;
>> + }
>> +
>> + if (!ssif_bmc->aborting && ssif_bmc->busy)
>> + ret = -EBUSY;
>> +
>> + spin_unlock_irqrestore(&ssif_bmc->lock, flags);
>> +
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc;
>> + int ret;
>> +
>> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
>> + if (!ssif_bmc)
>> + return -ENOMEM;
>> +
>> + spin_lock_init(&ssif_bmc->lock);
>> +
>> + init_waitqueue_head(&ssif_bmc->wait_queue);
>> + ssif_bmc->request_available = false;
>> + ssif_bmc->response_in_progress = false;
>> + ssif_bmc->busy = false;
>> + ssif_bmc->response_timer_inited = false;
>> +
>> + /* Register misc device interface */
>> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
>> + ssif_bmc->miscdev.name = DEVICE_NAME;
>> + ssif_bmc->miscdev.fops = &ssif_bmc_fops;
>> + ssif_bmc->miscdev.parent = &client->dev;
>> + ret = misc_register(&ssif_bmc->miscdev);
>> + if (ret)
>> + goto out;
>> +
>> + ssif_bmc->client = client;
>> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
>> +
>> + /* Register I2C slave */
>> + i2c_set_clientdata(client, ssif_bmc);
>> + ret = i2c_slave_register(client, ssif_bmc_cb);
>> + if (ret) {
>> + misc_deregister(&ssif_bmc->miscdev);
>> + goto out;
>> + }
>> +
>> + return 0;
>> +out:
>> + devm_kfree(&client->dev, ssif_bmc);
>> + return ret;
>> +}
>> +
>> +static int ssif_bmc_remove(struct i2c_client *client)
>> +{
>> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
>> +
>> + i2c_slave_unregister(client);
>> + misc_deregister(&ssif_bmc->miscdev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id ssif_bmc_match[] = {
>> + { .compatible = "ssif-bmc" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, ssif_bmc_match);
>> +
>> +static const struct i2c_device_id ssif_bmc_id[] = {
>> + { DEVICE_NAME, 0 },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
>> +
>> +static struct i2c_driver ssif_bmc_driver = {
>> + .driver = {
>> + .name = DEVICE_NAME,
>> + .of_match_table = ssif_bmc_match,
>> + },
>> + .probe = ssif_bmc_probe,
>> + .remove = ssif_bmc_remove,
>> + .id_table = ssif_bmc_id,
>> +};
>> +
>> +module_i2c_driver(ssif_bmc_driver);
>> +
>> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
>> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
>> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h
>> new file mode 100644
>> index 000000000000..2c3fc2a4698f
>> --- /dev/null
>> +++ b/drivers/char/ipmi/ssif_bmc.h
>> @@ -0,0 +1,107 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * The driver for BMC side of SSIF interface
>> + *
>> + * Copyright (c) 2022, Ampere Computing LLC
>> + *
>> + */
>> +#ifndef __SSIF_BMC_H__
>> +#define __SSIF_BMC_H__
>> +
>
> Is there any value in having a separate .h file for this? Unless you
> want to share something with the IPMI host side, which might make sense
> on some of the message numbers, but not a big deal, and even then you
> could put the .h file with the .c files.
>
> Except for the userspace API, which I will address later.
>
So far, there is no benefit to have separate .h file. So it will be
merged into one single .c file in next version.
>> +#define DEVICE_NAME "ipmi-ssif-host"
>> +
>> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
>> +
>> +/* A standard SMBus Transaction is limited to 32 data bytes */
>> +#define MAX_PAYLOAD_PER_TRANSACTION 32
>> +/* Transaction includes the address, the command, the length and the PEC byte */
>> +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
>> +
>> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30
>> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
>> +
>> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2
>> +#define SSIF_IPMI_SINGLEPART_READ 0x3
>> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6
>> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
>> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8
>> +#define SSIF_IPMI_MULTIPART_READ_START 0x3
>> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
>> +
>> +/* Include netfn and cmd field */
>> +#define MSG_PAYLOAD_LEN_MAX 254
>> +/*
>> + * IPMI 2.0 Spec, section 12.7 SSIF Timing,
>> + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
>> + * Recover ssif_bmc from busy state if it takes up to 500ms
>> + */
>> +#define RESPONSE_TIMEOUT 500 /* ms */
>> +
>
> I seem to remember mentioning this before, but there is no reason to
> pack the structures below.
>
The packed structure is because we want to pick the len directly from
user space without worry about the padding byte.
As we plan not to use the .h file in next version, I still would like to
use packed structure internally inside ssif_bmc.c file.
> And second, the following is a userspace API structures, so it needs to
> be in its own file in include/uapi/linux, along with any supporting
> things that users will need to use. And your userspace code should be
> using that file.
>
Meantime, I'd like not to use .h as I see there is no demand for sharing
the data structure between kernel and user space yet. But we may do it
in the future.
>> +struct ssif_msg {
>> + u8 len;
>
> Just to be 100% safe, it might be better to use a u16 on this. The spec
> sort of limits this to 255 bytes, but it also sort of leaves it open to
> be larger.
>
Yes, u8 only limited to 255 bytes and there is no space for future grow.
>> + u8 payload[MSG_PAYLOAD_LEN_MAX];
>> +} __packed;
>> +
>> +struct ssif_part_buffer {
>> + u8 address;
>> + u8 smbus_cmd;
>> + u8 length;
>> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
>> + u8 pec;
>> + u8 index;
>> +} __packed;
>> +
>> +/*
>> + * SSIF internal states:
>> + * SSIF_READY 0x00 : Ready state
>> + * SSIF_START 0x01 : Start smbus transaction
>> + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
>> + * SSIF_REQ_RECVING 0x03 : Receiving request
>> + * SSIF_RES_SENDING 0x04 : Sending response
>> + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
>> + */
>> +enum ssif_state {
>> + SSIF_READY,
>> + SSIF_START,
>> + SSIF_SMBUS_CMD,
>> + SSIF_REQ_RECVING,
>> + SSIF_RES_SENDING,
>> + SSIF_ABORTING,
>> + SSIF_STATE_MAX
>> +};
>> +
>> +struct ssif_bmc_ctx {
>> + struct i2c_client *client;
>> + struct miscdevice miscdev;
>> + int msg_idx;
>> + bool pec_support;
>> + /* ssif bmc spinlock */
>> + spinlock_t lock;
>> + wait_queue_head_t wait_queue;
>> + u8 running;
>> + enum ssif_state state;
>> + /* Timeout waiting for response */
>> + struct timer_list response_timer;
>> + bool response_timer_inited;
>> + /* Flag to identify a Multi-part Read Transaction */
>> + bool is_singlepart_read;
>> + u8 nbytes_processed;
>> + u8 remain_len;
>> + u8 recv_len;
>> + /* Block Number of a Multi-part Read Transaction */
>> + u8 block_num;
>> + bool request_available;
>> + bool response_in_progress;
>> + bool busy;
>> + bool aborting;
>> + /* Buffer for SSIF Transaction part*/
>> + struct ssif_part_buffer part_buf;
>> + struct ssif_msg response;
>> + struct ssif_msg request;
>> +};
>> +
>> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
>> +{
>> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
>> +}
>> +#endif /* __SSIF_BMC_H__ */
>> --
>> 2.35.1
>>
>>
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^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-05-04 6:45 ` Quan Nguyen
(?)
@ 2022-05-04 12:06 ` Corey Minyard
-1 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-05-04 12:06 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> >
> > I seem to remember mentioning this before, but there is no reason to
> > pack the structures below.
> >
>
> The packed structure is because we want to pick the len directly from user
> space without worry about the padding byte.
>
> As we plan not to use the .h file in next version, I still would like to use
> packed structure internally inside ssif_bmc.c file.
Packed doesn't matter for the userspace API. If you look at other
structures in the userspace API, they are not packed, either. The
compiler will do the right thing on both ends.
>
> > And second, the following is a userspace API structures, so it needs to
> > be in its own file in include/uapi/linux, along with any supporting
> > things that users will need to use. And your userspace code should be
> > using that file.
> >
>
> Meantime, I'd like not to use .h as I see there is no demand for sharing the
> data structure between kernel and user space yet. But we may do it in the
> future.
If you have a userspace API, it needs to be in include/uapi/linux.
You may not be the only user of this code. In fact, you probably won't
be. You need to have a .h with the structures in it, you don't want the
same structure in two places if you can help it.
>
> > > +struct ssif_msg {
> > > + u8 len;
> >
> > Just to be 100% safe, it might be better to use a u16 on this. The spec
> > sort of limits this to 255 bytes, but it also sort of leaves it open to
> > be larger.
> >
> Yes, u8 only limited to 255 bytes and there is no space for future grow.
Please make it a unsigned int for the length and __u8 for the data to
give necessary flexibility.
Thanks,
-corey
>
> > > + u8 payload[MSG_PAYLOAD_LEN_MAX];
> > > +} __packed;
> > > +
> > > +struct ssif_part_buffer {
> > > + u8 address;
> > > + u8 smbus_cmd;
> > > + u8 length;
> > > + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> > > + u8 pec;
> > > + u8 index;
> > > +} __packed;
> > > +
> > > +/*
> > > + * SSIF internal states:
> > > + * SSIF_READY 0x00 : Ready state
> > > + * SSIF_START 0x01 : Start smbus transaction
> > > + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> > > + * SSIF_REQ_RECVING 0x03 : Receiving request
> > > + * SSIF_RES_SENDING 0x04 : Sending response
> > > + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> > > + */
> > > +enum ssif_state {
> > > + SSIF_READY,
> > > + SSIF_START,
> > > + SSIF_SMBUS_CMD,
> > > + SSIF_REQ_RECVING,
> > > + SSIF_RES_SENDING,
> > > + SSIF_ABORTING,
> > > + SSIF_STATE_MAX
> > > +};
> > > +
> > > +struct ssif_bmc_ctx {
> > > + struct i2c_client *client;
> > > + struct miscdevice miscdev;
> > > + int msg_idx;
> > > + bool pec_support;
> > > + /* ssif bmc spinlock */
> > > + spinlock_t lock;
> > > + wait_queue_head_t wait_queue;
> > > + u8 running;
> > > + enum ssif_state state;
> > > + /* Timeout waiting for response */
> > > + struct timer_list response_timer;
> > > + bool response_timer_inited;
> > > + /* Flag to identify a Multi-part Read Transaction */
> > > + bool is_singlepart_read;
> > > + u8 nbytes_processed;
> > > + u8 remain_len;
> > > + u8 recv_len;
> > > + /* Block Number of a Multi-part Read Transaction */
> > > + u8 block_num;
> > > + bool request_available;
> > > + bool response_in_progress;
> > > + bool busy;
> > > + bool aborting;
> > > + /* Buffer for SSIF Transaction part*/
> > > + struct ssif_part_buffer part_buf;
> > > + struct ssif_msg response;
> > > + struct ssif_msg request;
> > > +};
> > > +
> > > +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> > > +{
> > > + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> > > +}
> > > +#endif /* __SSIF_BMC_H__ */
> > > --
> > > 2.35.1
> > >
> > >
>
>
>
> _______________________________________________
> Openipmi-developer mailing list
> Openipmi-developer@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/openipmi-developer
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-05-04 12:06 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-05-04 12:06 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, linux-i2c,
openipmi-developer, Open Source Submission, linux-arm-kernel
On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> >
> > I seem to remember mentioning this before, but there is no reason to
> > pack the structures below.
> >
>
> The packed structure is because we want to pick the len directly from user
> space without worry about the padding byte.
>
> As we plan not to use the .h file in next version, I still would like to use
> packed structure internally inside ssif_bmc.c file.
Packed doesn't matter for the userspace API. If you look at other
structures in the userspace API, they are not packed, either. The
compiler will do the right thing on both ends.
>
> > And second, the following is a userspace API structures, so it needs to
> > be in its own file in include/uapi/linux, along with any supporting
> > things that users will need to use. And your userspace code should be
> > using that file.
> >
>
> Meantime, I'd like not to use .h as I see there is no demand for sharing the
> data structure between kernel and user space yet. But we may do it in the
> future.
If you have a userspace API, it needs to be in include/uapi/linux.
You may not be the only user of this code. In fact, you probably won't
be. You need to have a .h with the structures in it, you don't want the
same structure in two places if you can help it.
>
> > > +struct ssif_msg {
> > > + u8 len;
> >
> > Just to be 100% safe, it might be better to use a u16 on this. The spec
> > sort of limits this to 255 bytes, but it also sort of leaves it open to
> > be larger.
> >
> Yes, u8 only limited to 255 bytes and there is no space for future grow.
Please make it a unsigned int for the length and __u8 for the data to
give necessary flexibility.
Thanks,
-corey
>
> > > + u8 payload[MSG_PAYLOAD_LEN_MAX];
> > > +} __packed;
> > > +
> > > +struct ssif_part_buffer {
> > > + u8 address;
> > > + u8 smbus_cmd;
> > > + u8 length;
> > > + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> > > + u8 pec;
> > > + u8 index;
> > > +} __packed;
> > > +
> > > +/*
> > > + * SSIF internal states:
> > > + * SSIF_READY 0x00 : Ready state
> > > + * SSIF_START 0x01 : Start smbus transaction
> > > + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> > > + * SSIF_REQ_RECVING 0x03 : Receiving request
> > > + * SSIF_RES_SENDING 0x04 : Sending response
> > > + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> > > + */
> > > +enum ssif_state {
> > > + SSIF_READY,
> > > + SSIF_START,
> > > + SSIF_SMBUS_CMD,
> > > + SSIF_REQ_RECVING,
> > > + SSIF_RES_SENDING,
> > > + SSIF_ABORTING,
> > > + SSIF_STATE_MAX
> > > +};
> > > +
> > > +struct ssif_bmc_ctx {
> > > + struct i2c_client *client;
> > > + struct miscdevice miscdev;
> > > + int msg_idx;
> > > + bool pec_support;
> > > + /* ssif bmc spinlock */
> > > + spinlock_t lock;
> > > + wait_queue_head_t wait_queue;
> > > + u8 running;
> > > + enum ssif_state state;
> > > + /* Timeout waiting for response */
> > > + struct timer_list response_timer;
> > > + bool response_timer_inited;
> > > + /* Flag to identify a Multi-part Read Transaction */
> > > + bool is_singlepart_read;
> > > + u8 nbytes_processed;
> > > + u8 remain_len;
> > > + u8 recv_len;
> > > + /* Block Number of a Multi-part Read Transaction */
> > > + u8 block_num;
> > > + bool request_available;
> > > + bool response_in_progress;
> > > + bool busy;
> > > + bool aborting;
> > > + /* Buffer for SSIF Transaction part*/
> > > + struct ssif_part_buffer part_buf;
> > > + struct ssif_msg response;
> > > + struct ssif_msg request;
> > > +};
> > > +
> > > +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> > > +{
> > > + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> > > +}
> > > +#endif /* __SSIF_BMC_H__ */
> > > --
> > > 2.35.1
> > >
> > >
>
>
>
> _______________________________________________
> Openipmi-developer mailing list
> Openipmi-developer@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/openipmi-developer
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-05-04 12:06 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-05-04 12:06 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> >
> > I seem to remember mentioning this before, but there is no reason to
> > pack the structures below.
> >
>
> The packed structure is because we want to pick the len directly from user
> space without worry about the padding byte.
>
> As we plan not to use the .h file in next version, I still would like to use
> packed structure internally inside ssif_bmc.c file.
Packed doesn't matter for the userspace API. If you look at other
structures in the userspace API, they are not packed, either. The
compiler will do the right thing on both ends.
>
> > And second, the following is a userspace API structures, so it needs to
> > be in its own file in include/uapi/linux, along with any supporting
> > things that users will need to use. And your userspace code should be
> > using that file.
> >
>
> Meantime, I'd like not to use .h as I see there is no demand for sharing the
> data structure between kernel and user space yet. But we may do it in the
> future.
If you have a userspace API, it needs to be in include/uapi/linux.
You may not be the only user of this code. In fact, you probably won't
be. You need to have a .h with the structures in it, you don't want the
same structure in two places if you can help it.
>
> > > +struct ssif_msg {
> > > + u8 len;
> >
> > Just to be 100% safe, it might be better to use a u16 on this. The spec
> > sort of limits this to 255 bytes, but it also sort of leaves it open to
> > be larger.
> >
> Yes, u8 only limited to 255 bytes and there is no space for future grow.
Please make it a unsigned int for the length and __u8 for the data to
give necessary flexibility.
Thanks,
-corey
>
> > > + u8 payload[MSG_PAYLOAD_LEN_MAX];
> > > +} __packed;
> > > +
> > > +struct ssif_part_buffer {
> > > + u8 address;
> > > + u8 smbus_cmd;
> > > + u8 length;
> > > + u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
> > > + u8 pec;
> > > + u8 index;
> > > +} __packed;
> > > +
> > > +/*
> > > + * SSIF internal states:
> > > + * SSIF_READY 0x00 : Ready state
> > > + * SSIF_START 0x01 : Start smbus transaction
> > > + * SSIF_SMBUS_CMD 0x02 : Received SMBus command
> > > + * SSIF_REQ_RECVING 0x03 : Receiving request
> > > + * SSIF_RES_SENDING 0x04 : Sending response
> > > + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction
> > > + */
> > > +enum ssif_state {
> > > + SSIF_READY,
> > > + SSIF_START,
> > > + SSIF_SMBUS_CMD,
> > > + SSIF_REQ_RECVING,
> > > + SSIF_RES_SENDING,
> > > + SSIF_ABORTING,
> > > + SSIF_STATE_MAX
> > > +};
> > > +
> > > +struct ssif_bmc_ctx {
> > > + struct i2c_client *client;
> > > + struct miscdevice miscdev;
> > > + int msg_idx;
> > > + bool pec_support;
> > > + /* ssif bmc spinlock */
> > > + spinlock_t lock;
> > > + wait_queue_head_t wait_queue;
> > > + u8 running;
> > > + enum ssif_state state;
> > > + /* Timeout waiting for response */
> > > + struct timer_list response_timer;
> > > + bool response_timer_inited;
> > > + /* Flag to identify a Multi-part Read Transaction */
> > > + bool is_singlepart_read;
> > > + u8 nbytes_processed;
> > > + u8 remain_len;
> > > + u8 recv_len;
> > > + /* Block Number of a Multi-part Read Transaction */
> > > + u8 block_num;
> > > + bool request_available;
> > > + bool response_in_progress;
> > > + bool busy;
> > > + bool aborting;
> > > + /* Buffer for SSIF Transaction part*/
> > > + struct ssif_part_buffer part_buf;
> > > + struct ssif_msg response;
> > > + struct ssif_msg request;
> > > +};
> > > +
> > > +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
> > > +{
> > > + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
> > > +}
> > > +#endif /* __SSIF_BMC_H__ */
> > > --
> > > 2.35.1
> > >
> > >
>
>
>
> _______________________________________________
> Openipmi-developer mailing list
> Openipmi-developer@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/openipmi-developer
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-04-22 4:08 ` Quan Nguyen
(?)
@ 2022-05-14 14:31 ` Wolfram Sang
-1 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-05-14 14:31 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1: Type: text/plain, Size: 313 bytes --]
On Fri, Apr 22, 2022 at 11:08:03AM +0700, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
That should be I2C_SLAVE_WRITE_RECEIVED and it should be NAKed on all
errnos. Have you tested it?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-05-14 14:31 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-05-14 14:31 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Corey Minyard, Krzysztof Kozlowski,
Andrew Jeffery, openbmc, Thang Q . Nguyen, Brendan Higgins,
linux-kernel, Phong Vo, Rob Herring, Joel Stanley,
openipmi-developer, Open Source Submission, linux-arm-kernel,
linux-i2c
[-- Attachment #1: Type: text/plain, Size: 313 bytes --]
On Fri, Apr 22, 2022 at 11:08:03AM +0700, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
That should be I2C_SLAVE_WRITE_RECEIVED and it should be NAKed on all
errnos. Have you tested it?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-05-14 14:31 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-05-14 14:31 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1.1: Type: text/plain, Size: 313 bytes --]
On Fri, Apr 22, 2022 at 11:08:03AM +0700, Quan Nguyen wrote:
> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
> on the bus.
That should be I2C_SLAVE_WRITE_RECEIVED and it should be NAKed on all
errnos. Have you tested it?
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-05-14 14:31 ` Wolfram Sang
@ 2022-05-16 2:32 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-05-16 2:32 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 14/05/2022 21:31, Wolfram Sang wrote:
> On Fri, Apr 22, 2022 at 11:08:03AM +0700, Quan Nguyen wrote:
>> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
>> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
>> on the bus.
>
> That should be I2C_SLAVE_WRITE_RECEIVED and it should be NAKed on all
> errnos. Have you tested it?
>
Dear Wolfram,
Thanks for the comment.
Yes, we have tested this patch with ast2500 and see it works well
without the need of the ugly slave_enable/disable() as before.
When tested with ast2500, it is observed that there's always a
I2C_SLAVE_WRITE_REQUESTED comes first then other
I2C_SLAVE_WRITE_RECEIVED's follow for all transactions.
In case slave is busy, the NAK will be asserted on the first occurrence
of I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction
(host later will retry with other transaction) until slave ready.
This behavior is expected as we want host to drop all transactions while
slave is busy on working on the response. That is why we choose to
assert NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction
instead of I2C_SLAVE_WRITE_RECEIVED.
As we are interested in this specific case, ie: to assert NAK only when
slave busy, we dont want to force the current aspeed's slave to assert
NAK in all errno's. That is why we choose to NAK only when there is an
explicitly -EBUSY return from slave.
Thank you for the review and hope to see further comments.
Thanks,
- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-05-16 2:32 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-05-16 2:32 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 14/05/2022 21:31, Wolfram Sang wrote:
> On Fri, Apr 22, 2022 at 11:08:03AM +0700, Quan Nguyen wrote:
>> When processing I2C_SLAVE_WRITE_REQUESTED event, if slave returns
>> -EBUSY, i2c controller should issue RxCmdLast command to assert NAK
>> on the bus.
>
> That should be I2C_SLAVE_WRITE_RECEIVED and it should be NAKed on all
> errnos. Have you tested it?
>
Dear Wolfram,
Thanks for the comment.
Yes, we have tested this patch with ast2500 and see it works well
without the need of the ugly slave_enable/disable() as before.
When tested with ast2500, it is observed that there's always a
I2C_SLAVE_WRITE_REQUESTED comes first then other
I2C_SLAVE_WRITE_RECEIVED's follow for all transactions.
In case slave is busy, the NAK will be asserted on the first occurrence
of I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction
(host later will retry with other transaction) until slave ready.
This behavior is expected as we want host to drop all transactions while
slave is busy on working on the response. That is why we choose to
assert NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction
instead of I2C_SLAVE_WRITE_RECEIVED.
As we are interested in this specific case, ie: to assert NAK only when
slave busy, we dont want to force the current aspeed's slave to assert
NAK in all errno's. That is why we choose to NAK only when there is an
explicitly -EBUSY return from slave.
Thank you for the review and hope to see further comments.
Thanks,
- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-05-04 12:06 ` Corey Minyard
(?)
@ 2022-06-01 8:23 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-01 8:23 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On 04/05/2022 19:06, Corey Minyard wrote:
> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>
>>> I seem to remember mentioning this before, but there is no reason to
>>> pack the structures below.
>>>
>>
>> The packed structure is because we want to pick the len directly from user
>> space without worry about the padding byte.
>>
>> As we plan not to use the .h file in next version, I still would like to use
>> packed structure internally inside ssif_bmc.c file.
>
> Packed doesn't matter for the userspace API. If you look at other
> structures in the userspace API, they are not packed, either. The
> compiler will do the right thing on both ends.
>
>>
>>> And second, the following is a userspace API structures, so it needs to
>>> be in its own file in include/uapi/linux, along with any supporting
>>> things that users will need to use. And your userspace code should be
>>> using that file.
>>>
>>
>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>> data structure between kernel and user space yet. But we may do it in the
>> future.
>
> If you have a userspace API, it needs to be in include/uapi/linux.
> You may not be the only user of this code. In fact, you probably won't
> be. You need to have a .h with the structures in it, you don't want the
> same structure in two places if you can help it.
>
Dear Corey,
Is it OK to push the structure definition into the
include/uapi/linux/ipmi_bmc.h ?
Or should it need to be in separate new header file in uapi/linux ?
Thank you,
- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-01 8:23 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-01 8:23 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, linux-i2c,
openipmi-developer, Open Source Submission, linux-arm-kernel
On 04/05/2022 19:06, Corey Minyard wrote:
> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>
>>> I seem to remember mentioning this before, but there is no reason to
>>> pack the structures below.
>>>
>>
>> The packed structure is because we want to pick the len directly from user
>> space without worry about the padding byte.
>>
>> As we plan not to use the .h file in next version, I still would like to use
>> packed structure internally inside ssif_bmc.c file.
>
> Packed doesn't matter for the userspace API. If you look at other
> structures in the userspace API, they are not packed, either. The
> compiler will do the right thing on both ends.
>
>>
>>> And second, the following is a userspace API structures, so it needs to
>>> be in its own file in include/uapi/linux, along with any supporting
>>> things that users will need to use. And your userspace code should be
>>> using that file.
>>>
>>
>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>> data structure between kernel and user space yet. But we may do it in the
>> future.
>
> If you have a userspace API, it needs to be in include/uapi/linux.
> You may not be the only user of this code. In fact, you probably won't
> be. You need to have a .h with the structures in it, you don't want the
> same structure in two places if you can help it.
>
Dear Corey,
Is it OK to push the structure definition into the
include/uapi/linux/ipmi_bmc.h ?
Or should it need to be in separate new header file in uapi/linux ?
Thank you,
- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-01 8:23 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-01 8:23 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On 04/05/2022 19:06, Corey Minyard wrote:
> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>
>>> I seem to remember mentioning this before, but there is no reason to
>>> pack the structures below.
>>>
>>
>> The packed structure is because we want to pick the len directly from user
>> space without worry about the padding byte.
>>
>> As we plan not to use the .h file in next version, I still would like to use
>> packed structure internally inside ssif_bmc.c file.
>
> Packed doesn't matter for the userspace API. If you look at other
> structures in the userspace API, they are not packed, either. The
> compiler will do the right thing on both ends.
>
>>
>>> And second, the following is a userspace API structures, so it needs to
>>> be in its own file in include/uapi/linux, along with any supporting
>>> things that users will need to use. And your userspace code should be
>>> using that file.
>>>
>>
>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>> data structure between kernel and user space yet. But we may do it in the
>> future.
>
> If you have a userspace API, it needs to be in include/uapi/linux.
> You may not be the only user of this code. In fact, you probably won't
> be. You need to have a .h with the structures in it, you don't want the
> same structure in two places if you can help it.
>
Dear Corey,
Is it OK to push the structure definition into the
include/uapi/linux/ipmi_bmc.h ?
Or should it need to be in separate new header file in uapi/linux ?
Thank you,
- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-06-01 8:23 ` Quan Nguyen
(?)
@ 2022-06-02 0:32 ` Corey Minyard
-1 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-06-02 0:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
> On 04/05/2022 19:06, Corey Minyard wrote:
> > On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> > > >
> > > > I seem to remember mentioning this before, but there is no reason to
> > > > pack the structures below.
> > > >
> > >
> > > The packed structure is because we want to pick the len directly from user
> > > space without worry about the padding byte.
> > >
> > > As we plan not to use the .h file in next version, I still would like to use
> > > packed structure internally inside ssif_bmc.c file.
> >
> > Packed doesn't matter for the userspace API. If you look at other
> > structures in the userspace API, they are not packed, either. The
> > compiler will do the right thing on both ends.
> >
> > >
> > > > And second, the following is a userspace API structures, so it needs to
> > > > be in its own file in include/uapi/linux, along with any supporting
> > > > things that users will need to use. And your userspace code should be
> > > > using that file.
> > > >
> > >
> > > Meantime, I'd like not to use .h as I see there is no demand for sharing the
> > > data structure between kernel and user space yet. But we may do it in the
> > > future.
> >
> > If you have a userspace API, it needs to be in include/uapi/linux.
> > You may not be the only user of this code. In fact, you probably won't
> > be. You need to have a .h with the structures in it, you don't want the
> > same structure in two places if you can help it.
> >
>
> Dear Corey,
>
> Is it OK to push the structure definition into the
> include/uapi/linux/ipmi_bmc.h ?
>
> Or should it need to be in separate new header file in uapi/linux ?
I think a different file, like ipmi_ssif_bmc, to match the file and
operation. Unless you need the things in ipmi_bmc.h, which I don't
think is the case.
-corey
>
> Thank you,
> - Quan
>
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-02 0:32 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-06-02 0:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, linux-i2c,
openipmi-developer, Open Source Submission, linux-arm-kernel
On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
> On 04/05/2022 19:06, Corey Minyard wrote:
> > On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> > > >
> > > > I seem to remember mentioning this before, but there is no reason to
> > > > pack the structures below.
> > > >
> > >
> > > The packed structure is because we want to pick the len directly from user
> > > space without worry about the padding byte.
> > >
> > > As we plan not to use the .h file in next version, I still would like to use
> > > packed structure internally inside ssif_bmc.c file.
> >
> > Packed doesn't matter for the userspace API. If you look at other
> > structures in the userspace API, they are not packed, either. The
> > compiler will do the right thing on both ends.
> >
> > >
> > > > And second, the following is a userspace API structures, so it needs to
> > > > be in its own file in include/uapi/linux, along with any supporting
> > > > things that users will need to use. And your userspace code should be
> > > > using that file.
> > > >
> > >
> > > Meantime, I'd like not to use .h as I see there is no demand for sharing the
> > > data structure between kernel and user space yet. But we may do it in the
> > > future.
> >
> > If you have a userspace API, it needs to be in include/uapi/linux.
> > You may not be the only user of this code. In fact, you probably won't
> > be. You need to have a .h with the structures in it, you don't want the
> > same structure in two places if you can help it.
> >
>
> Dear Corey,
>
> Is it OK to push the structure definition into the
> include/uapi/linux/ipmi_bmc.h ?
>
> Or should it need to be in separate new header file in uapi/linux ?
I think a different file, like ipmi_ssif_bmc, to match the file and
operation. Unless you need the things in ipmi_bmc.h, which I don't
think is the case.
-corey
>
> Thank you,
> - Quan
>
>
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-02 0:32 ` Corey Minyard
0 siblings, 0 replies; 67+ messages in thread
From: Corey Minyard @ 2022-06-02 0:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Krzysztof Kozlowski, Andrew Jeffery,
Benjamin Herrenschmidt, openbmc, Thang Q . Nguyen,
Brendan Higgins, linux-kernel, Phong Vo, Wolfram Sang,
Rob Herring, openipmi-developer, Open Source Submission,
linux-arm-kernel, linux-i2c
On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
> On 04/05/2022 19:06, Corey Minyard wrote:
> > On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> > > >
> > > > I seem to remember mentioning this before, but there is no reason to
> > > > pack the structures below.
> > > >
> > >
> > > The packed structure is because we want to pick the len directly from user
> > > space without worry about the padding byte.
> > >
> > > As we plan not to use the .h file in next version, I still would like to use
> > > packed structure internally inside ssif_bmc.c file.
> >
> > Packed doesn't matter for the userspace API. If you look at other
> > structures in the userspace API, they are not packed, either. The
> > compiler will do the right thing on both ends.
> >
> > >
> > > > And second, the following is a userspace API structures, so it needs to
> > > > be in its own file in include/uapi/linux, along with any supporting
> > > > things that users will need to use. And your userspace code should be
> > > > using that file.
> > > >
> > >
> > > Meantime, I'd like not to use .h as I see there is no demand for sharing the
> > > data structure between kernel and user space yet. But we may do it in the
> > > future.
> >
> > If you have a userspace API, it needs to be in include/uapi/linux.
> > You may not be the only user of this code. In fact, you probably won't
> > be. You need to have a .h with the structures in it, you don't want the
> > same structure in two places if you can help it.
> >
>
> Dear Corey,
>
> Is it OK to push the structure definition into the
> include/uapi/linux/ipmi_bmc.h ?
>
> Or should it need to be in separate new header file in uapi/linux ?
I think a different file, like ipmi_ssif_bmc, to match the file and
operation. Unless you need the things in ipmi_bmc.h, which I don't
think is the case.
-corey
>
> Thank you,
> - Quan
>
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
2022-06-02 0:32 ` Corey Minyard
(?)
@ 2022-06-02 9:38 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-02 9:38 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Andrew Jeffery, Benjamin Herrenschmidt,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, openipmi-developer,
Open Source Submission, linux-arm-kernel, linux-i2c,
Krzysztof Kozlowski
On 02/06/2022 07:32, Corey Minyard wrote:
> On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
>> On 04/05/2022 19:06, Corey Minyard wrote:
>>> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>>>
>>>>> I seem to remember mentioning this before, but there is no reason to
>>>>> pack the structures below.
>>>>>
>>>>
>>>> The packed structure is because we want to pick the len directly from user
>>>> space without worry about the padding byte.
>>>>
>>>> As we plan not to use the .h file in next version, I still would like to use
>>>> packed structure internally inside ssif_bmc.c file.
>>>
>>> Packed doesn't matter for the userspace API. If you look at other
>>> structures in the userspace API, they are not packed, either. The
>>> compiler will do the right thing on both ends.
>>>
>>>>
>>>>> And second, the following is a userspace API structures, so it needs to
>>>>> be in its own file in include/uapi/linux, along with any supporting
>>>>> things that users will need to use. And your userspace code should be
>>>>> using that file.
>>>>>
>>>>
>>>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>>>> data structure between kernel and user space yet. But we may do it in the
>>>> future.
>>>
>>> If you have a userspace API, it needs to be in include/uapi/linux.
>>> You may not be the only user of this code. In fact, you probably won't
>>> be. You need to have a .h with the structures in it, you don't want the
>>> same structure in two places if you can help it.
>>>
>>
>> Dear Corey,
>>
>> Is it OK to push the structure definition into the
>> include/uapi/linux/ipmi_bmc.h ?
>>
>> Or should it need to be in separate new header file in uapi/linux ?
>
> I think a different file, like ipmi_ssif_bmc, to match the file and
> operation. Unless you need the things in ipmi_bmc.h, which I don't
> think is the case.
>
Thanks Corey,
Will add ipmi_ssif_bmc as you suggested.
-- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-02 9:38 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-02 9:38 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Andrew Jeffery, openbmc,
Thang Q . Nguyen, Brendan Higgins, linux-kernel, Phong Vo,
Wolfram Sang, Rob Herring, linux-i2c, Krzysztof Kozlowski,
openipmi-developer, Open Source Submission, linux-arm-kernel
On 02/06/2022 07:32, Corey Minyard wrote:
> On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
>> On 04/05/2022 19:06, Corey Minyard wrote:
>>> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>>>
>>>>> I seem to remember mentioning this before, but there is no reason to
>>>>> pack the structures below.
>>>>>
>>>>
>>>> The packed structure is because we want to pick the len directly from user
>>>> space without worry about the padding byte.
>>>>
>>>> As we plan not to use the .h file in next version, I still would like to use
>>>> packed structure internally inside ssif_bmc.c file.
>>>
>>> Packed doesn't matter for the userspace API. If you look at other
>>> structures in the userspace API, they are not packed, either. The
>>> compiler will do the right thing on both ends.
>>>
>>>>
>>>>> And second, the following is a userspace API structures, so it needs to
>>>>> be in its own file in include/uapi/linux, along with any supporting
>>>>> things that users will need to use. And your userspace code should be
>>>>> using that file.
>>>>>
>>>>
>>>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>>>> data structure between kernel and user space yet. But we may do it in the
>>>> future.
>>>
>>> If you have a userspace API, it needs to be in include/uapi/linux.
>>> You may not be the only user of this code. In fact, you probably won't
>>> be. You need to have a .h with the structures in it, you don't want the
>>> same structure in two places if you can help it.
>>>
>>
>> Dear Corey,
>>
>> Is it OK to push the structure definition into the
>> include/uapi/linux/ipmi_bmc.h ?
>>
>> Or should it need to be in separate new header file in uapi/linux ?
>
> I think a different file, like ipmi_ssif_bmc, to match the file and
> operation. Unless you need the things in ipmi_bmc.h, which I don't
> think is the case.
>
Thanks Corey,
Will add ipmi_ssif_bmc as you suggested.
-- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC driver
@ 2022-06-02 9:38 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-02 9:38 UTC (permalink / raw)
To: minyard
Cc: devicetree, linux-aspeed, Andrew Jeffery, Benjamin Herrenschmidt,
openbmc, Thang Q . Nguyen, Brendan Higgins, linux-kernel,
Phong Vo, Wolfram Sang, Rob Herring, openipmi-developer,
Open Source Submission, linux-arm-kernel, linux-i2c,
Krzysztof Kozlowski
On 02/06/2022 07:32, Corey Minyard wrote:
> On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
>> On 04/05/2022 19:06, Corey Minyard wrote:
>>> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>>>
>>>>> I seem to remember mentioning this before, but there is no reason to
>>>>> pack the structures below.
>>>>>
>>>>
>>>> The packed structure is because we want to pick the len directly from user
>>>> space without worry about the padding byte.
>>>>
>>>> As we plan not to use the .h file in next version, I still would like to use
>>>> packed structure internally inside ssif_bmc.c file.
>>>
>>> Packed doesn't matter for the userspace API. If you look at other
>>> structures in the userspace API, they are not packed, either. The
>>> compiler will do the right thing on both ends.
>>>
>>>>
>>>>> And second, the following is a userspace API structures, so it needs to
>>>>> be in its own file in include/uapi/linux, along with any supporting
>>>>> things that users will need to use. And your userspace code should be
>>>>> using that file.
>>>>>
>>>>
>>>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>>>> data structure between kernel and user space yet. But we may do it in the
>>>> future.
>>>
>>> If you have a userspace API, it needs to be in include/uapi/linux.
>>> You may not be the only user of this code. In fact, you probably won't
>>> be. You need to have a .h with the structures in it, you don't want the
>>> same structure in two places if you can help it.
>>>
>>
>> Dear Corey,
>>
>> Is it OK to push the structure definition into the
>> include/uapi/linux/ipmi_bmc.h ?
>>
>> Or should it need to be in separate new header file in uapi/linux ?
>
> I think a different file, like ipmi_ssif_bmc, to match the file and
> operation. Unless you need the things in ipmi_bmc.h, which I don't
> think is the case.
>
Thanks Corey,
Will add ipmi_ssif_bmc as you suggested.
-- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-05-16 2:32 ` Quan Nguyen
(?)
@ 2022-06-15 20:32 ` Wolfram Sang
-1 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-15 20:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1: Type: text/plain, Size: 1469 bytes --]
Hi Quan,
> When tested with ast2500, it is observed that there's always a
> I2C_SLAVE_WRITE_REQUESTED comes first then other I2C_SLAVE_WRITE_RECEIVED's
> follow for all transactions.
Yes, that's the design of the interface :)
> In case slave is busy, the NAK will be asserted on the first occurrence of
> I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction (host
> later will retry with other transaction) until slave ready.
>
> This behavior is expected as we want host to drop all transactions while
> slave is busy on working on the response. That is why we choose to assert
> NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction instead of
> I2C_SLAVE_WRITE_RECEIVED.
From Documentation/i2c/slave-interface.rst:
===
About ACK/NACK
--------------
It is good behaviour to always ACK the address phase, so the master knows if a
device is basically present or if it mysteriously disappeared. Using NACK to
state being busy is troublesome. SMBus demands to always ACK the address phase,
while the I2C specification is more loose on that. Most I2C controllers also
automatically ACK when detecting their slave addresses, so there is no option
to NACK them. For those reasons, this API does not support NACK in the address
phase.
===
So, the proper design is to NACK on the first received byte. All EEPROMs
do it this way when they are busy because of erasing a page.
All the best,
Wolfram
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-15 20:32 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-15 20:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Corey Minyard, Krzysztof Kozlowski,
Andrew Jeffery, openbmc, Thang Q . Nguyen, Brendan Higgins,
linux-kernel, Phong Vo, Rob Herring, Joel Stanley,
openipmi-developer, Open Source Submission, linux-arm-kernel,
linux-i2c
[-- Attachment #1: Type: text/plain, Size: 1469 bytes --]
Hi Quan,
> When tested with ast2500, it is observed that there's always a
> I2C_SLAVE_WRITE_REQUESTED comes first then other I2C_SLAVE_WRITE_RECEIVED's
> follow for all transactions.
Yes, that's the design of the interface :)
> In case slave is busy, the NAK will be asserted on the first occurrence of
> I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction (host
> later will retry with other transaction) until slave ready.
>
> This behavior is expected as we want host to drop all transactions while
> slave is busy on working on the response. That is why we choose to assert
> NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction instead of
> I2C_SLAVE_WRITE_RECEIVED.
From Documentation/i2c/slave-interface.rst:
===
About ACK/NACK
--------------
It is good behaviour to always ACK the address phase, so the master knows if a
device is basically present or if it mysteriously disappeared. Using NACK to
state being busy is troublesome. SMBus demands to always ACK the address phase,
while the I2C specification is more loose on that. Most I2C controllers also
automatically ACK when detecting their slave addresses, so there is no option
to NACK them. For those reasons, this API does not support NACK in the address
phase.
===
So, the proper design is to NACK on the first received byte. All EEPROMs
do it this way when they are busy because of erasing a page.
All the best,
Wolfram
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-15 20:32 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-15 20:32 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1.1: Type: text/plain, Size: 1469 bytes --]
Hi Quan,
> When tested with ast2500, it is observed that there's always a
> I2C_SLAVE_WRITE_REQUESTED comes first then other I2C_SLAVE_WRITE_RECEIVED's
> follow for all transactions.
Yes, that's the design of the interface :)
> In case slave is busy, the NAK will be asserted on the first occurrence of
> I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction (host
> later will retry with other transaction) until slave ready.
>
> This behavior is expected as we want host to drop all transactions while
> slave is busy on working on the response. That is why we choose to assert
> NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction instead of
> I2C_SLAVE_WRITE_RECEIVED.
From Documentation/i2c/slave-interface.rst:
===
About ACK/NACK
--------------
It is good behaviour to always ACK the address phase, so the master knows if a
device is basically present or if it mysteriously disappeared. Using NACK to
state being busy is troublesome. SMBus demands to always ACK the address phase,
while the I2C specification is more loose on that. Most I2C controllers also
automatically ACK when detecting their slave addresses, so there is no option
to NACK them. For those reasons, this API does not support NACK in the address
phase.
===
So, the proper design is to NACK on the first received byte. All EEPROMs
do it this way when they are busy because of erasing a page.
All the best,
Wolfram
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-06-15 20:32 ` Wolfram Sang
@ 2022-06-16 7:16 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-16 7:16 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 16/06/2022 03:32, Wolfram Sang wrote:
> Hi Quan,
>
>> When tested with ast2500, it is observed that there's always a
>> I2C_SLAVE_WRITE_REQUESTED comes first then other I2C_SLAVE_WRITE_RECEIVED's
>> follow for all transactions.
>
> Yes, that's the design of the interface :)
>
>> In case slave is busy, the NAK will be asserted on the first occurrence of
>> I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction (host
>> later will retry with other transaction) until slave ready.
>>
>> This behavior is expected as we want host to drop all transactions while
>> slave is busy on working on the response. That is why we choose to assert
>> NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction instead of
>> I2C_SLAVE_WRITE_RECEIVED.
>
> From Documentation/i2c/slave-interface.rst:
>
> ===
>
> About ACK/NACK
> --------------
>
> It is good behaviour to always ACK the address phase, so the master knows if a
> device is basically present or if it mysteriously disappeared. Using NACK to
> state being busy is troublesome. SMBus demands to always ACK the address phase,
> while the I2C specification is more loose on that. Most I2C controllers also
> automatically ACK when detecting their slave addresses, so there is no option
> to NACK them. For those reasons, this API does not support NACK in the address
> phase.
>
> ===
>
> So, the proper design is to NACK on the first received byte. All EEPROMs
> do it this way when they are busy because of erasing a page.
>
Thanks Wolfram for the review.
On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is
already received with ACK. So if slave return -EBUSY, the NAK will occur
on the next Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
Tested this patch and capture using Saleae tool, it always shows ACK on
the address and NAK on the first byte follow when slave return -EBUSY,
ie: the byte follow the address, which is single part read command
(0x03) in my case.
+ When slave return -EBUSY:
S-> Aw(ACK)-> RxD(NAK)-> P
0x10 0x03 (Singlepart read)
+ When slave ready:
S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
0x10 0x03 0x07 ... 0xDE
Using the Logic 2 (with Saleae tool) to capture, we could see the log as
below:
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
...
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave is ready
read to 0x10 ack data: 0x07 0xF4 0x1D 0x00 0x01 0x00 0x00 0x00 0xDE
Thanks,
- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-16 7:16 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-16 7:16 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 16/06/2022 03:32, Wolfram Sang wrote:
> Hi Quan,
>
>> When tested with ast2500, it is observed that there's always a
>> I2C_SLAVE_WRITE_REQUESTED comes first then other I2C_SLAVE_WRITE_RECEIVED's
>> follow for all transactions.
>
> Yes, that's the design of the interface :)
>
>> In case slave is busy, the NAK will be asserted on the first occurrence of
>> I2C_SLAVE_WRITE_REQUESTED make host to stop the current transaction (host
>> later will retry with other transaction) until slave ready.
>>
>> This behavior is expected as we want host to drop all transactions while
>> slave is busy on working on the response. That is why we choose to assert
>> NAK on the first I2C_SLAVE_WRITE_REQUESTED of the transaction instead of
>> I2C_SLAVE_WRITE_RECEIVED.
>
> From Documentation/i2c/slave-interface.rst:
>
> ===
>
> About ACK/NACK
> --------------
>
> It is good behaviour to always ACK the address phase, so the master knows if a
> device is basically present or if it mysteriously disappeared. Using NACK to
> state being busy is troublesome. SMBus demands to always ACK the address phase,
> while the I2C specification is more loose on that. Most I2C controllers also
> automatically ACK when detecting their slave addresses, so there is no option
> to NACK them. For those reasons, this API does not support NACK in the address
> phase.
>
> ===
>
> So, the proper design is to NACK on the first received byte. All EEPROMs
> do it this way when they are busy because of erasing a page.
>
Thanks Wolfram for the review.
On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is
already received with ACK. So if slave return -EBUSY, the NAK will occur
on the next Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
Tested this patch and capture using Saleae tool, it always shows ACK on
the address and NAK on the first byte follow when slave return -EBUSY,
ie: the byte follow the address, which is single part read command
(0x03) in my case.
+ When slave return -EBUSY:
S-> Aw(ACK)-> RxD(NAK)-> P
0x10 0x03 (Singlepart read)
+ When slave ready:
S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
0x10 0x03 0x07 ... 0xDE
Using the Logic 2 (with Saleae tool) to capture, we could see the log as
below:
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
...
write to 0x10 ack data: 0x03 <= when slave return -EBUSY
write to 0x10 ack data: 0x03 <= when slave is ready
read to 0x10 ack data: 0x07 0xF4 0x1D 0x00 0x01 0x00 0x00 0x00 0xDE
Thanks,
- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-06-16 7:16 ` Quan Nguyen
(?)
@ 2022-06-16 12:29 ` Wolfram Sang
-1 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-16 12:29 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1: Type: text/plain, Size: 836 bytes --]
Hi Quan,
> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is already
> received with ACK. So if slave return -EBUSY, the NAK will occur on the next
> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
From the docs:
===
* I2C_SLAVE_WRITE_RECEIVED (mandatory)
'val': bus driver delivers received byte
'ret': 0 if the byte should be acked, some errno if the byte should be nacked
Another I2C master has sent a byte to us which needs to be set in 'val'. If 'ret'
is zero, the bus driver should ack this byte. If 'ret' is an errno, then the byte
should be nacked.
===
'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
you need, or? Does the aspeed driver not support acking the current
byte?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-16 12:29 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-16 12:29 UTC (permalink / raw)
To: Quan Nguyen
Cc: devicetree, linux-aspeed, Corey Minyard, Krzysztof Kozlowski,
Andrew Jeffery, openbmc, Thang Q . Nguyen, Brendan Higgins,
linux-kernel, Phong Vo, Rob Herring, Joel Stanley,
openipmi-developer, Open Source Submission, linux-arm-kernel,
linux-i2c
[-- Attachment #1: Type: text/plain, Size: 836 bytes --]
Hi Quan,
> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is already
> received with ACK. So if slave return -EBUSY, the NAK will occur on the next
> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
From the docs:
===
* I2C_SLAVE_WRITE_RECEIVED (mandatory)
'val': bus driver delivers received byte
'ret': 0 if the byte should be acked, some errno if the byte should be nacked
Another I2C master has sent a byte to us which needs to be set in 'val'. If 'ret'
is zero, the bus driver should ack this byte. If 'ret' is an errno, then the byte
should be nacked.
===
'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
you need, or? Does the aspeed driver not support acking the current
byte?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-16 12:29 ` Wolfram Sang
0 siblings, 0 replies; 67+ messages in thread
From: Wolfram Sang @ 2022-06-16 12:29 UTC (permalink / raw)
To: Quan Nguyen
Cc: Corey Minyard, Rob Herring, Krzysztof Kozlowski, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen
[-- Attachment #1.1: Type: text/plain, Size: 836 bytes --]
Hi Quan,
> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is already
> received with ACK. So if slave return -EBUSY, the NAK will occur on the next
> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
From the docs:
===
* I2C_SLAVE_WRITE_RECEIVED (mandatory)
'val': bus driver delivers received byte
'ret': 0 if the byte should be acked, some errno if the byte should be nacked
Another I2C master has sent a byte to us which needs to be set in 'val'. If 'ret'
is zero, the bus driver should ack this byte. If 'ret' is an errno, then the byte
should be nacked.
===
'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
you need, or? Does the aspeed driver not support acking the current
byte?
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-06-16 12:29 ` Wolfram Sang
@ 2022-06-17 7:08 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-17 7:08 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 16/06/2022 19:29, Wolfram Sang wrote:
> Hi Quan,
>
>> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is already
>> received with ACK. So if slave return -EBUSY, the NAK will occur on the next
>> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
>
> This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
> From the docs:
>
> ===
>
> * I2C_SLAVE_WRITE_RECEIVED (mandatory)
>
> 'val': bus driver delivers received byte
>
> 'ret': 0 if the byte should be acked, some errno if the byte should be nacked
>
> Another I2C master has sent a byte to us which needs to be set in 'val'. If 'ret'
> is zero, the bus driver should ack this byte. If 'ret' is an errno, then the byte
> should be nacked.
>
> ===
>
> 'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
> you need, or? Does the aspeed driver not support acking the current
> byte?
>
It is true that aspeed driver does not support acking the current byte.
Setting ASPEED_I2CD_M_S_RX_CMD_LAST will take effect on the next Rx byte
as per my observation.
S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
(1) (2)
Currently, setting ASPEED_I2CD_M_S_RX_CMD_LAST in (1), on
I2C_SLAVE_WRITE_REQUESTED event, will make the NAK happen in (2) and
make the read stop.
If setting ASPEED_I2CD_M_S_RX_CMD_LAST on (2), ie: on
I2C_SLAVE_WRITE_RECEIVED event, the read from Master is never NAK
because there is no next Rx byte and Master is already switch to read
from Slave.
I understands that the return of
i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value) is always 0 as
in Documentation/i2c/slave-interface.rst. But with this case, this is
the way to NAK on the first byte and I'm wonder if this particular case
would be supported somehow.
Thanks,
-- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-06-17 7:08 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-06-17 7:08 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Krzysztof Kozlowski,
Joel Stanley, Andrew Jeffery, Brendan Higgins,
Benjamin Herrenschmidt, openipmi-developer, devicetree,
linux-arm-kernel, linux-aspeed, linux-kernel, linux-i2c, openbmc,
Open Source Submission, Phong Vo, Thang Q . Nguyen
On 16/06/2022 19:29, Wolfram Sang wrote:
> Hi Quan,
>
>> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is already
>> received with ACK. So if slave return -EBUSY, the NAK will occur on the next
>> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
>
> This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
> From the docs:
>
> ===
>
> * I2C_SLAVE_WRITE_RECEIVED (mandatory)
>
> 'val': bus driver delivers received byte
>
> 'ret': 0 if the byte should be acked, some errno if the byte should be nacked
>
> Another I2C master has sent a byte to us which needs to be set in 'val'. If 'ret'
> is zero, the bus driver should ack this byte. If 'ret' is an errno, then the byte
> should be nacked.
>
> ===
>
> 'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
> you need, or? Does the aspeed driver not support acking the current
> byte?
>
It is true that aspeed driver does not support acking the current byte.
Setting ASPEED_I2CD_M_S_RX_CMD_LAST will take effect on the next Rx byte
as per my observation.
S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
(1) (2)
Currently, setting ASPEED_I2CD_M_S_RX_CMD_LAST in (1), on
I2C_SLAVE_WRITE_REQUESTED event, will make the NAK happen in (2) and
make the read stop.
If setting ASPEED_I2CD_M_S_RX_CMD_LAST on (2), ie: on
I2C_SLAVE_WRITE_RECEIVED event, the read from Master is never NAK
because there is no next Rx byte and Master is already switch to read
from Slave.
I understands that the return of
i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value) is always 0 as
in Documentation/i2c/slave-interface.rst. But with this case, this is
the way to NAK on the first byte and I'm wonder if this particular case
would be supported somehow.
Thanks,
-- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
2022-06-17 7:08 ` Quan Nguyen
@ 2022-07-05 2:45 ` Quan Nguyen
-1 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-07-05 2:45 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen, Krzysztof Kozlowski
On 17/06/2022 14:08, Quan Nguyen wrote:
> On 16/06/2022 19:29, Wolfram Sang wrote:
>> Hi Quan,
>>
>>> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is
>>> already
>>> received with ACK. So if slave return -EBUSY, the NAK will occur on
>>> the next
>>> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
>>
>> This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
>> From the docs:
>>
>> ===
>>
>> * I2C_SLAVE_WRITE_RECEIVED (mandatory)
>>
>> 'val': bus driver delivers received byte
>>
>> 'ret': 0 if the byte should be acked, some errno if the byte should
>> be nacked
>>
>> Another I2C master has sent a byte to us which needs to be set in
>> 'val'. If 'ret'
>> is zero, the bus driver should ack this byte. If 'ret' is an errno,
>> then the byte
>> should be nacked.
>>
>> ===
>>
>> 'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
>> you need, or? Does the aspeed driver not support acking the current
>> byte?
>>
>
> It is true that aspeed driver does not support acking the current byte.
> Setting ASPEED_I2CD_M_S_RX_CMD_LAST will take effect on the next Rx byte
> as per my observation.
>
> S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
> (1) (2)
>
> Currently, setting ASPEED_I2CD_M_S_RX_CMD_LAST in (1), on
> I2C_SLAVE_WRITE_REQUESTED event, will make the NAK happen in (2) and
> make the read stop.
>
> If setting ASPEED_I2CD_M_S_RX_CMD_LAST on (2), ie: on
> I2C_SLAVE_WRITE_RECEIVED event, the read from Master is never NAK
> because there is no next Rx byte and Master is already switch to read
> from Slave.
>
> I understands that the return of
> i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value) is always 0 as
> in Documentation/i2c/slave-interface.rst. But with this case, this is
> the way to NAK on the first byte and I'm wonder if this particular case
> would be supported somehow.
>
Dear Wolfram,
From my particular case, as it seems not to be able to nak on the
current byte on I2C_SLAVE_WRITE_RECEIVED event (i2c-aspeed), is it
possible to somehow allow slave to return some errno on the
I2C_SLAVE_WRITE_REQUESTED event so that bus driver knows what to do for
the next incoming byte if slave is busy?
As from the docs:
===
* I2C_SLAVE_WRITE_REQUESTED (mandatory)
'val': unused
'ret': always 0
Another I2C master wants to write data to us. This event should be sent once
our own address and the write bit was detected. The data did not arrive
yet, so
there is nothing to process or return. Wakeup or initialization probably
needs
to be done, though.
===
As the "Wakeup or initialization probably needs to be done" in the slave
side, in case slave is fail to either wake up or initialization or busy
in this particular case, there is no way for slave to let the bus driver
know the status if the 'ret' is always 0.
I'm also agree that it should be always ack on I2C_SLAVE_WRITE_REQUESTED
event (when the slave address matched and the write bit detected). But
if slave know it is fail to either wakeup or initialization or busy, the
bus driver should be able to automatically to nak on the first write
incoming byte.
Hence, my thinking is to change the above:
'ret': always 0
to:
'ret': 0 otherwise some errno if slave is busy or fail to wakeup or
initialization
Thank you and best regards,
- Quan
^ permalink raw reply [flat|nested] 67+ messages in thread
* Re: [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy
@ 2022-07-05 2:45 ` Quan Nguyen
0 siblings, 0 replies; 67+ messages in thread
From: Quan Nguyen @ 2022-07-05 2:45 UTC (permalink / raw)
To: Wolfram Sang, Corey Minyard, Rob Herring, Joel Stanley,
Andrew Jeffery, Brendan Higgins, Benjamin Herrenschmidt,
openipmi-developer, devicetree, linux-arm-kernel, linux-aspeed,
linux-kernel, linux-i2c, openbmc, Open Source Submission,
Phong Vo, Thang Q . Nguyen, Krzysztof Kozlowski
On 17/06/2022 14:08, Quan Nguyen wrote:
> On 16/06/2022 19:29, Wolfram Sang wrote:
>> Hi Quan,
>>
>>> On the first occurrence of I2C_SLAVE_WRITE_REQUESTED, the address is
>>> already
>>> received with ACK. So if slave return -EBUSY, the NAK will occur on
>>> the next
>>> Rx byte (on I2C_SLAVE_WRITE_RECEIVED event).
>>
>> This is exactly why I2C_SLAVE_WRITE_RECEIVED allows for an error code.
>> From the docs:
>>
>> ===
>>
>> * I2C_SLAVE_WRITE_RECEIVED (mandatory)
>>
>> 'val': bus driver delivers received byte
>>
>> 'ret': 0 if the byte should be acked, some errno if the byte should
>> be nacked
>>
>> Another I2C master has sent a byte to us which needs to be set in
>> 'val'. If 'ret'
>> is zero, the bus driver should ack this byte. If 'ret' is an errno,
>> then the byte
>> should be nacked.
>>
>> ===
>>
>> 'ret' is used to ACK/NACK the current byte in 'val'. That's exactly what
>> you need, or? Does the aspeed driver not support acking the current
>> byte?
>>
>
> It is true that aspeed driver does not support acking the current byte.
> Setting ASPEED_I2CD_M_S_RX_CMD_LAST will take effect on the next Rx byte
> as per my observation.
>
> S-> Aw(ACK)-> RxD(ACK)-> Sr-> Ar-> TxD(ACK)-> ... -> TxD(NAK)-> P
> (1) (2)
>
> Currently, setting ASPEED_I2CD_M_S_RX_CMD_LAST in (1), on
> I2C_SLAVE_WRITE_REQUESTED event, will make the NAK happen in (2) and
> make the read stop.
>
> If setting ASPEED_I2CD_M_S_RX_CMD_LAST on (2), ie: on
> I2C_SLAVE_WRITE_RECEIVED event, the read from Master is never NAK
> because there is no next Rx byte and Master is already switch to read
> from Slave.
>
> I understands that the return of
> i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value) is always 0 as
> in Documentation/i2c/slave-interface.rst. But with this case, this is
> the way to NAK on the first byte and I'm wonder if this particular case
> would be supported somehow.
>
Dear Wolfram,
From my particular case, as it seems not to be able to nak on the
current byte on I2C_SLAVE_WRITE_RECEIVED event (i2c-aspeed), is it
possible to somehow allow slave to return some errno on the
I2C_SLAVE_WRITE_REQUESTED event so that bus driver knows what to do for
the next incoming byte if slave is busy?
As from the docs:
===
* I2C_SLAVE_WRITE_REQUESTED (mandatory)
'val': unused
'ret': always 0
Another I2C master wants to write data to us. This event should be sent once
our own address and the write bit was detected. The data did not arrive
yet, so
there is nothing to process or return. Wakeup or initialization probably
needs
to be done, though.
===
As the "Wakeup or initialization probably needs to be done" in the slave
side, in case slave is fail to either wake up or initialization or busy
in this particular case, there is no way for slave to let the bus driver
know the status if the 'ret' is always 0.
I'm also agree that it should be always ack on I2C_SLAVE_WRITE_REQUESTED
event (when the slave address matched and the write bit detected). But
if slave know it is fail to either wakeup or initialization or busy, the
bus driver should be able to automatically to nak on the first write
incoming byte.
Hence, my thinking is to change the above:
'ret': always 0
to:
'ret': 0 otherwise some errno if slave is busy or fail to wakeup or
initialization
Thank you and best regards,
- Quan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 67+ messages in thread
end of thread, other threads:[~2022-07-05 2:47 UTC | newest]
Thread overview: 67+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-22 4:08 [PATCH v7 0/3] Add SSIF BMC driver Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:08 ` [PATCH v7 1/3] ipmi: ssif_bmc: " Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-23 1:51 ` Corey Minyard
2022-04-23 1:51 ` Corey Minyard
2022-04-23 1:51 ` Corey Minyard
2022-05-04 6:45 ` Quan Nguyen
2022-05-04 6:45 ` Quan Nguyen
2022-05-04 6:45 ` Quan Nguyen
2022-05-04 12:06 ` [Openipmi-developer] " Corey Minyard
2022-05-04 12:06 ` Corey Minyard
2022-05-04 12:06 ` Corey Minyard
2022-06-01 8:23 ` Quan Nguyen
2022-06-01 8:23 ` Quan Nguyen
2022-06-01 8:23 ` Quan Nguyen
2022-06-02 0:32 ` Corey Minyard
2022-06-02 0:32 ` Corey Minyard
2022-06-02 0:32 ` Corey Minyard
2022-06-02 9:38 ` Quan Nguyen
2022-06-02 9:38 ` Quan Nguyen
2022-06-02 9:38 ` Quan Nguyen
2022-04-22 4:08 ` [PATCH v7 2/3] bindings: ipmi: Add binding for " Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 7:21 ` Krzysztof Kozlowski
2022-04-22 7:21 ` Krzysztof Kozlowski
2022-04-22 7:56 ` Quan Nguyen
2022-04-22 7:56 ` Quan Nguyen
2022-04-22 7:56 ` Quan Nguyen
2022-04-25 21:39 ` Rob Herring
2022-04-25 21:39 ` Rob Herring
2022-04-25 21:39 ` Rob Herring
2022-04-22 4:08 ` [PATCH v7 3/3] i2c: aspeed: Assert NAK when slave is busy Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:08 ` Quan Nguyen
2022-04-22 4:17 ` Quan Nguyen
2022-04-22 4:17 ` Quan Nguyen
2022-04-22 4:17 ` Quan Nguyen
2022-05-14 14:31 ` Wolfram Sang
2022-05-14 14:31 ` Wolfram Sang
2022-05-14 14:31 ` Wolfram Sang
2022-05-16 2:32 ` Quan Nguyen
2022-05-16 2:32 ` Quan Nguyen
2022-06-15 20:32 ` Wolfram Sang
2022-06-15 20:32 ` Wolfram Sang
2022-06-15 20:32 ` Wolfram Sang
2022-06-16 7:16 ` Quan Nguyen
2022-06-16 7:16 ` Quan Nguyen
2022-06-16 12:29 ` Wolfram Sang
2022-06-16 12:29 ` Wolfram Sang
2022-06-16 12:29 ` Wolfram Sang
2022-06-17 7:08 ` Quan Nguyen
2022-06-17 7:08 ` Quan Nguyen
2022-07-05 2:45 ` Quan Nguyen
2022-07-05 2:45 ` Quan Nguyen
2022-04-22 4:16 ` [PATCH v7 0/3] Add SSIF BMC driver Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
2022-04-22 4:16 ` Quan Nguyen
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