* [PATCH v16 00/14] Introduce the Counter character device interface
@ 2021-08-27 3:47 William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities William Breathitt Gray
` (14 more replies)
0 siblings, 15 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
Changes in v16:
- Define magic numbers for stm32-lptimer-cnt clock polarities
- Define magic numbers for stm32-timer-cnt encoder modes
- Bump KernelVersion to 5.16 in sysfs-bus-counter ABI documentation
- Fix typos in driver API generic-counter.rst documentation file
For convenience, this patchset is also available on my personal git
repo: https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v16
The patches preceding "counter: Internalize sysfs interface code" are
primarily cleanup and fixes that can be picked up and applied now to the
IIO tree if so desired. The "counter: Internalize sysfs interface code"
patch as well may be considered for pickup because it is relatively safe
and makes no changes to the userspace interface.
To summarize the main points of this patchset: there are no changes to
the existing Counter sysfs userspace interface; a Counter character
device interface is introduced that allows Counter events and associated
data to be read() by userspace; the events_configure() and
watch_validate() driver callbacks are introduced to support Counter
events; and IRQ support is added to the 104-QUAD-8 driver, serving as an
example of how to support the new Counter events functionality.
William Breathitt Gray (14):
counter: stm32-lptimer-cnt: Provide defines for clock polarities
counter: stm32-timer-cnt: Provide defines for slave mode selection
counter: Internalize sysfs interface code
counter: Update counter.h comments to reflect sysfs internalization
docs: counter: Update to reflect sysfs internalization
counter: Move counter enums to uapi header
counter: Add character device interface
docs: counter: Document character device interface
tools/counter: Create Counter tools
counter: Implement signalZ_action_component_id sysfs attribute
counter: Implement *_component_id sysfs attributes
counter: Implement events_queue_size sysfs attribute
counter: 104-quad-8: Replace mutex with spinlock
counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
Documentation/ABI/testing/sysfs-bus-counter | 38 +-
Documentation/driver-api/generic-counter.rst | 358 +++-
.../userspace-api/ioctl/ioctl-number.rst | 1 +
MAINTAINERS | 3 +-
drivers/counter/104-quad-8.c | 699 ++++----
drivers/counter/Kconfig | 6 +-
drivers/counter/Makefile | 1 +
drivers/counter/counter-chrdev.c | 553 ++++++
drivers/counter/counter-chrdev.h | 14 +
drivers/counter/counter-core.c | 191 +++
drivers/counter/counter-sysfs.c | 960 +++++++++++
drivers/counter/counter-sysfs.h | 13 +
drivers/counter/counter.c | 1496 -----------------
drivers/counter/ftm-quaddec.c | 60 +-
drivers/counter/intel-qep.c | 144 +-
drivers/counter/interrupt-cnt.c | 62 +-
drivers/counter/microchip-tcb-capture.c | 91 +-
drivers/counter/stm32-lptimer-cnt.c | 212 ++-
drivers/counter/stm32-timer-cnt.c | 195 +--
drivers/counter/ti-eqep.c | 180 +-
include/linux/counter.h | 715 ++++----
include/linux/counter_enum.h | 45 -
include/linux/mfd/stm32-lptimer.h | 5 +
include/linux/mfd/stm32-timers.h | 4 +
include/uapi/linux/counter.h | 154 ++
tools/Makefile | 13 +-
tools/counter/Build | 1 +
tools/counter/Makefile | 53 +
tools/counter/counter_example.c | 93 +
29 files changed, 3569 insertions(+), 2791 deletions(-)
create mode 100644 drivers/counter/counter-chrdev.c
create mode 100644 drivers/counter/counter-chrdev.h
create mode 100644 drivers/counter/counter-core.c
create mode 100644 drivers/counter/counter-sysfs.c
create mode 100644 drivers/counter/counter-sysfs.h
delete mode 100644 drivers/counter/counter.c
delete mode 100644 include/linux/counter_enum.h
create mode 100644 include/uapi/linux/counter.h
create mode 100644 tools/counter/Build
create mode 100644 tools/counter/Makefile
create mode 100644 tools/counter/counter_example.c
base-commit: 5ffeb17c0d3dd44704b4aee83e297ec07666e4d6
--
2.32.0
^ permalink raw reply [flat|nested] 32+ messages in thread
* [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-31 13:38 ` Fabrice Gasnier
2021-08-27 3:47 ` [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection William Breathitt Gray
` (13 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Fabrice Gasnier
The STM32 low-power timer permits configuration of the clock polarity
via the LPTIMX_CFGR register CKPOL bits. This patch provides
preprocessor defines for the supported clock polarities.
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/stm32-lptimer-cnt.c | 6 +++---
include/linux/mfd/stm32-lptimer.h | 5 +++++
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 13656957c45f..7367f46c6f91 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -140,9 +140,9 @@ static const enum counter_function stm32_lptim_cnt_functions[] = {
};
enum stm32_lptim_synapse_action {
- STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
- STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
- STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
+ STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE = STM32_LPTIM_CKPOL_RISING_EDGE,
+ STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE = STM32_LPTIM_CKPOL_FALLING_EDGE,
+ STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES = STM32_LPTIM_CKPOL_BOTH_EDGES,
STM32_LPTIM_SYNAPSE_ACTION_NONE,
};
diff --git a/include/linux/mfd/stm32-lptimer.h b/include/linux/mfd/stm32-lptimer.h
index 90b20550c1c8..06d3f11dc3c9 100644
--- a/include/linux/mfd/stm32-lptimer.h
+++ b/include/linux/mfd/stm32-lptimer.h
@@ -45,6 +45,11 @@
#define STM32_LPTIM_PRESC GENMASK(11, 9)
#define STM32_LPTIM_CKPOL GENMASK(2, 1)
+/* STM32_LPTIM_CKPOL */
+#define STM32_LPTIM_CKPOL_RISING_EDGE 0
+#define STM32_LPTIM_CKPOL_FALLING_EDGE 1
+#define STM32_LPTIM_CKPOL_BOTH_EDGES 2
+
/* STM32_LPTIM_ARR */
#define STM32_LPTIM_MAX_ARR 0xFFFF
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-31 13:40 ` Fabrice Gasnier
2021-08-27 3:47 ` [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
` (12 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Fabrice Gasnier
The STM32 timer permits configuration of the counter encoder mode via
the slave mode control register (SMCR) slave mode selection (SMS) bits.
This patch provides preprocessor defines for the supported encoder
modes.
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/stm32-timer-cnt.c | 16 ++++++++--------
include/linux/mfd/stm32-timers.h | 4 ++++
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 3fb0debd7425..1fbc46f4ee66 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -93,16 +93,16 @@ static int stm32_count_function_get(struct counter_device *counter,
regmap_read(priv->regmap, TIM_SMCR, &smcr);
switch (smcr & TIM_SMCR_SMS) {
- case 0:
+ case TIM_SMCR_SMS_SLAVE_MODE_DISABLED:
*function = STM32_COUNT_SLAVE_MODE_DISABLED;
return 0;
- case 1:
+ case TIM_SMCR_SMS_ENCODER_MODE_1:
*function = STM32_COUNT_ENCODER_MODE_1;
return 0;
- case 2:
+ case TIM_SMCR_SMS_ENCODER_MODE_2:
*function = STM32_COUNT_ENCODER_MODE_2;
return 0;
- case 3:
+ case TIM_SMCR_SMS_ENCODER_MODE_3:
*function = STM32_COUNT_ENCODER_MODE_3;
return 0;
default:
@@ -119,16 +119,16 @@ static int stm32_count_function_set(struct counter_device *counter,
switch (function) {
case STM32_COUNT_SLAVE_MODE_DISABLED:
- sms = 0;
+ sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
break;
case STM32_COUNT_ENCODER_MODE_1:
- sms = 1;
+ sms = TIM_SMCR_SMS_ENCODER_MODE_1;
break;
case STM32_COUNT_ENCODER_MODE_2:
- sms = 2;
+ sms = TIM_SMCR_SMS_ENCODER_MODE_2;
break;
case STM32_COUNT_ENCODER_MODE_3:
- sms = 3;
+ sms = TIM_SMCR_SMS_ENCODER_MODE_3;
break;
default:
return -EINVAL;
diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
index f8db83aedb2b..5f5c43fd69dd 100644
--- a/include/linux/mfd/stm32-timers.h
+++ b/include/linux/mfd/stm32-timers.h
@@ -82,6 +82,10 @@
#define MAX_TIM_ICPSC 0x3
#define TIM_CR2_MMS_SHIFT 4
#define TIM_CR2_MMS2_SHIFT 20
+#define TIM_SMCR_SMS_SLAVE_MODE_DISABLED 0 /* counts on internal clock when CEN=1 */
+#define TIM_SMCR_SMS_ENCODER_MODE_1 1 /* counts TI1FP1 edges, depending on TI2FP2 level */
+#define TIM_SMCR_SMS_ENCODER_MODE_2 2 /* counts TI2FP2 edges, depending on TI1FP1 level */
+#define TIM_SMCR_SMS_ENCODER_MODE_3 3 /* counts on both TI1FP1 and TI2FP2 edges */
#define TIM_SMCR_TS_SHIFT 4
#define TIM_BDTR_BKF_MASK 0xF
#define TIM_BDTR_BKF_SHIFT(x) (16 + (x) * 4)
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-09-08 17:46 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 05/14] docs: counter: Update " William Breathitt Gray
` (11 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
The Counter subsystem architecture and driver implementations have
changed in order to handle Counter sysfs interactions in a more
consistent way. This patch updates the Generic Counter interface
header file comments to reflect the changes.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/counter-core.c | 3 ++
include/linux/counter.h | 62 ++++++++++++++++------------------
2 files changed, 33 insertions(+), 32 deletions(-)
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
index c533a6ff12cf..3cda2c47bacb 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -38,6 +38,9 @@ static struct bus_type counter_bus_type = {
* This function registers a Counter to the system. A sysfs "counter" directory
* will be created and populated with sysfs attributes correlating with the
* Counter Signals, Synapses, and Counts respectively.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
*/
int counter_register(struct counter_device *const counter)
{
diff --git a/include/linux/counter.h b/include/linux/counter.h
index b69277f5c4c5..445f22d8bfe2 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -188,11 +188,10 @@ struct counter_comp {
/**
* struct counter_signal - Counter Signal node
- * @id: unique ID used to identify signal
- * @name: device-specific Signal name; ideally, this should match the name
- * as it appears in the datasheet documentation
- * @ext: optional array of Counter Signal extensions
- * @num_ext: number of Counter Signal extensions specified in @ext
+ * @id: unique ID used to identify the Signal
+ * @name: device-specific Signal name
+ * @ext: optional array of Signal extensions
+ * @num_ext: number of Signal extensions specified in @ext
*/
struct counter_signal {
int id;
@@ -206,7 +205,7 @@ struct counter_signal {
* struct counter_synapse - Counter Synapse node
* @actions_list: array of available action modes
* @num_actions: number of action modes specified in @actions_list
- * @signal: pointer to associated signal
+ * @signal: pointer to the associated Signal
*/
struct counter_synapse {
const enum counter_synapse_action *actions_list;
@@ -217,15 +216,14 @@ struct counter_synapse {
/**
* struct counter_count - Counter Count node
- * @id: unique ID used to identify Count
- * @name: device-specific Count name; ideally, this should match
- * the name as it appears in the datasheet documentation
- * @functions_list: array available function modes
+ * @id: unique ID used to identify the Count
+ * @name: device-specific Count name
+ * @functions_list: array of available function modes
* @num_functions: number of function modes specified in @functions_list
- * @synapses: array of synapses for initialization
- * @num_synapses: number of synapses specified in @synapses
- * @ext: optional array of Counter Count extensions
- * @num_ext: number of Counter Count extensions specified in @ext
+ * @synapses: array of Synapses for initialization
+ * @num_synapses: number of Synapses specified in @synapses
+ * @ext: optional array of Count extensions
+ * @num_ext: number of Count extensions specified in @ext
*/
struct counter_count {
int id;
@@ -243,27 +241,27 @@ struct counter_count {
/**
* struct counter_ops - Callbacks from driver
- * @signal_read: optional read callback for Signal attribute. The read
- * level of the respective Signal should be passed back via
- * the level parameter.
- * @count_read: optional read callback for Count attribute. The read
- * value of the respective Count should be passed back via
- * the val parameter.
- * @count_write: optional write callback for Count attribute. The write
- * value for the respective Count is passed in via the val
+ * @signal_read: optional read callback for Signals. The read level of
+ * the respective Signal should be passed back via the
+ * level parameter.
+ * @count_read: read callback for Counts. The read value of the
+ * respective Count should be passed back via the value
+ * parameter.
+ * @count_write: optional write callback for Counts. The write value for
+ * the respective Count is passed in via the value
* parameter.
* @function_read: read callback the Count function modes. The read
* function mode of the respective Count should be passed
* back via the function parameter.
- * @function_write: write callback for Count function modes. The function
- * mode to write for the respective Count is passed in via
- * the function parameter.
- * @action_read: read callback the Synapse action modes. The read action
- * mode of the respective Synapse should be passed back via
- * the action parameter.
- * @action_write: write callback for Synapse action modes. The action mode
- * to write for the respective Synapse is passed in via the
- * action parameter.
+ * @function_write: optional write callback for Count function modes. The
+ * function mode to write for the respective Count is
+ * passed in via the function parameter.
+ * @action_read: optional read callback the Synapse action modes. The
+ * read action mode of the respective Synapse should be
+ * passed back via the action parameter.
+ * @action_write: optional write callback for Synapse action modes. The
+ * action mode to write for the respective Synapse is
+ * passed in via the action parameter.
*/
struct counter_ops {
int (*signal_read)(struct counter_device *counter,
@@ -291,7 +289,7 @@ struct counter_ops {
/**
* struct counter_device - Counter data structure
- * @name: name of the device as it appears in the datasheet
+ * @name: name of the device
* @parent: optional parent device providing the counters
* @ops: callbacks from driver
* @signals: array of Signals
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 05/14] docs: counter: Update to reflect sysfs internalization
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (2 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-09-08 17:48 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 06/14] counter: Move counter enums to uapi header William Breathitt Gray
` (10 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
The Counter subsystem architecture and driver implementations have
changed in order to handle Counter sysfs interactions in a more
consistent way. This patch updates the Generic Counter interface
documentation to reflect the changes.
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Documentation/ABI/testing/sysfs-bus-counter | 9 +-
Documentation/driver-api/generic-counter.rst | 243 ++++++++++++++-----
2 files changed, 185 insertions(+), 67 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 20fe5afd4f9e..dee79b606847 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -286,7 +286,14 @@ What: /sys/bus/counter/devices/counterX/signalY/signal
KernelVersion: 5.2
Contact: linux-iio@vger.kernel.org
Description:
- Signal data of Signal Y represented as a string.
+ Signal level state of Signal Y. The following signal level
+ states are available:
+
+ low:
+ Low level state.
+
+ high:
+ High level state.
What: /sys/bus/counter/devices/counterX/signalY/synchronous_mode
KernelVersion: 5.2
diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index 64fe7db080e5..f6397218aa4c 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -250,8 +250,8 @@ for defining a counter device.
.. kernel-doc:: drivers/counter/counter.c
:export:
-Implementation
-==============
+Driver Implementation
+=====================
To support a counter device, a driver must first allocate the available
Counter Signals via counter_signal structures. These Signals should
@@ -267,25 +267,61 @@ respective counter_count structure. These counter_count structures are
set to the counts array member of an allocated counter_device structure
before the Counter is registered to the system.
-Driver callbacks should be provided to the counter_device structure via
-a constant counter_ops structure in order to communicate with the
-device: to read and write various Signals and Counts, and to set and get
-the "action mode" and "function mode" for various Synapses and Counts
-respectively.
+Driver callbacks must be provided to the counter_device structure in
+order to communicate with the device: to read and write various Signals
+and Counts, and to set and get the "action mode" and "function mode" for
+various Synapses and Counts respectively.
A defined counter_device structure may be registered to the system by
passing it to the counter_register function, and unregistered by passing
it to the counter_unregister function. Similarly, the
-devm_counter_register and devm_counter_unregister functions may be used
-if device memory-managed registration is desired.
-
-Extension sysfs attributes can be created for auxiliary functionality
-and data by passing in defined counter_device_ext, counter_count_ext,
-and counter_signal_ext structures. In these cases, the
-counter_device_ext structure is used for global/miscellaneous exposure
-and configuration of the respective Counter device, while the
-counter_count_ext and counter_signal_ext structures allow for auxiliary
-exposure and configuration of a specific Count or Signal respectively.
+devm_counter_register function may be used if device memory-managed
+registration is desired.
+
+The struct counter_comp structure is used to define counter extensions
+for Signals, Synapses, and Counts.
+
+The "type" member specifies the type of high-level data (e.g. BOOL,
+COUNT_DIRECTION, etc.) handled by this extension. The "``*_read``" and
+"``*_write``" members can then be set by the counter device driver with
+callbacks to handle that data using native C data types (i.e. u8, u64,
+etc.).
+
+Convenience macros such as ``COUNTER_COMP_COUNT_U64`` are provided for
+use by driver authors. In particular, driver authors are expected to use
+the provided macros for standard Counter subsystem attributes in order
+to maintain a consistent interface for userspace. For example, a counter
+device driver may define several standard attributes like so::
+
+ struct counter_comp count_ext[] = {
+ COUNTER_COMP_DIRECTION(count_direction_read),
+ COUNTER_COMP_ENABLE(count_enable_read, count_enable_write),
+ COUNTER_COMP_CEILING(count_ceiling_read, count_ceiling_write),
+ };
+
+This makes it simple to see, add, and modify the attributes that are
+supported by this driver ("direction", "enable", and "ceiling") and to
+maintain this code without getting lost in a web of struct braces.
+
+Callbacks must match the function type expected for the respective
+component or extension. These function types are defined in the struct
+counter_comp structure as the "``*_read``" and "``*_write``" union
+members.
+
+The corresponding callback prototypes for the extensions mentioned in
+the previous example above would be::
+
+ int count_direction_read(struct counter_device *counter,
+ struct counter_count *count,
+ enum counter_count_direction *direction);
+ int count_enable_read(struct counter_device *counter,
+ struct counter_count *count, u8 *enable);
+ int count_enable_write(struct counter_device *counter,
+ struct counter_count *count, u8 enable);
+ int count_ceiling_read(struct counter_device *counter,
+ struct counter_count *count, u64 *ceiling);
+ int count_ceiling_write(struct counter_device *counter,
+ struct counter_count *count, u64 ceiling);
Determining the type of extension to create is a matter of scope.
@@ -313,52 +349,127 @@ Determining the type of extension to create is a matter of scope.
chip overheated via a device extension called "error_overtemp":
/sys/bus/counter/devices/counterX/error_overtemp
-Architecture
-============
-
-When the Generic Counter interface counter module is loaded, the
-counter_init function is called which registers a bus_type named
-"counter" to the system. Subsequently, when the module is unloaded, the
-counter_exit function is called which unregisters the bus_type named
-"counter" from the system.
-
-Counter devices are registered to the system via the counter_register
-function, and later removed via the counter_unregister function. The
-counter_register function establishes a unique ID for the Counter
-device and creates a respective sysfs directory, where X is the
-mentioned unique ID:
-
- /sys/bus/counter/devices/counterX
-
-Sysfs attributes are created within the counterX directory to expose
-functionality, configurations, and data relating to the Counts, Signals,
-and Synapses of the Counter device, as well as options and information
-for the Counter device itself.
-
-Each Signal has a directory created to house its relevant sysfs
-attributes, where Y is the unique ID of the respective Signal:
-
- /sys/bus/counter/devices/counterX/signalY
-
-Similarly, each Count has a directory created to house its relevant
-sysfs attributes, where Y is the unique ID of the respective Count:
-
- /sys/bus/counter/devices/counterX/countY
-
-For a more detailed breakdown of the available Generic Counter interface
-sysfs attributes, please refer to the
-Documentation/ABI/testing/sysfs-bus-counter file.
-
-The Signals and Counts associated with the Counter device are registered
-to the system as well by the counter_register function. The
-signal_read/signal_write driver callbacks are associated with their
-respective Signal attributes, while the count_read/count_write and
-function_get/function_set driver callbacks are associated with their
-respective Count attributes; similarly, the same is true for the
-action_get/action_set driver callbacks and their respective Synapse
-attributes. If a driver callback is left undefined, then the respective
-read/write permission is left disabled for the relevant attributes.
-
-Similarly, extension sysfs attributes are created for the defined
-counter_device_ext, counter_count_ext, and counter_signal_ext
-structures that are passed in.
+Subsystem Architecture
+======================
+
+Counter drivers pass and take data natively (i.e. ``u8``, ``u64``, etc.)
+and the shared counter module handles the translation between the sysfs
+interface. This guarantees a standard userspace interface for all
+counter drivers, and enables a Generic Counter chrdev interface via a
+generalized device driver ABI.
+
+A high-level view of how a count value is passed down from a counter
+driver is exemplified by the following. The driver callbacks are first
+registered to the Counter core component for use by the Counter
+userspace interface components::
+
+ Driver callbacks registration:
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ +----------------------------+
+ | Counter device driver |
+ +----------------------------+
+ | Processes data from device |
+ +----------------------------+
+ |
+ -------------------
+ / driver callbacks /
+ -------------------
+ |
+ V
+ +----------------------+
+ | Counter core |
+ +----------------------+
+ | Routes device driver |
+ | callbacks to the |
+ | userspace interfaces |
+ +----------------------+
+ |
+ -------------------
+ / driver callbacks /
+ -------------------
+ |
+ +---------------+
+ |
+ V
+ +--------------------+
+ | Counter sysfs |
+ +--------------------+
+ | Translates to the |
+ | standard Counter |
+ | sysfs output |
+ +--------------------+
+
+Thereafter, data can be transferred directly between the Counter device
+driver and Counter userspace interface::
+
+ Count data request:
+ ~~~~~~~~~~~~~~~~~~~
+ ----------------------
+ / Counter device \
+ +----------------------+
+ | Count register: 0x28 |
+ +----------------------+
+ |
+ -----------------
+ / raw count data /
+ -----------------
+ |
+ V
+ +----------------------------+
+ | Counter device driver |
+ +----------------------------+
+ | Processes data from device |
+ |----------------------------|
+ | Type: u64 |
+ | Value: 42 |
+ +----------------------------+
+ |
+ ----------
+ / u64 /
+ ----------
+ |
+ +---------------+
+ |
+ V
+ +--------------------+
+ | Counter sysfs |
+ +--------------------+
+ | Translates to the |
+ | standard Counter |
+ | sysfs output |
+ |--------------------|
+ | Type: const char * |
+ | Value: "42" |
+ +--------------------+
+ |
+ ---------------
+ / const char * /
+ ---------------
+ |
+ V
+ +--------------------------------------------------+
+ | `/sys/bus/counter/devices/counterX/countY/count` |
+ +--------------------------------------------------+
+ \ Count: "42" /
+ --------------------------------------------------
+
+There are three primary components involved:
+
+Counter device driver
+---------------------
+Communicates with the hardware device to read/write data; e.g. counter
+drivers for quadrature encoders, timers, etc.
+
+Counter core
+------------
+Registers the counter device driver to the system so that the respective
+callbacks are called during userspace interaction.
+
+Counter sysfs
+-------------
+Translates counter data to the standard Counter sysfs interface format
+and vice versa.
+
+Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
+for a detailed breakdown of the available Generic Counter interface
+sysfs attributes.
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 06/14] counter: Move counter enums to uapi header
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (3 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 05/14] docs: counter: Update " William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 07/14] counter: Add character device interface William Breathitt Gray
` (9 subsequent siblings)
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
This is in preparation for a subsequent patch implementing a character
device interface for the Counter subsystem.
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
MAINTAINERS | 1 +
include/linux/counter.h | 42 +--------------------------
include/uapi/linux/counter.h | 56 ++++++++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+), 41 deletions(-)
create mode 100644 include/uapi/linux/counter.h
diff --git a/MAINTAINERS b/MAINTAINERS
index b0cdb9aaca85..f2fdd2202605 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4781,6 +4781,7 @@ F: Documentation/ABI/testing/sysfs-bus-counter
F: Documentation/driver-api/generic-counter.rst
F: drivers/counter/
F: include/linux/counter.h
+F: include/uapi/linux/counter.h
CP2615 I2C DRIVER
M: Bence Csókás <bence98@sch.bme.hu>
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 445f22d8bfe2..7c9f7e23953a 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -9,6 +9,7 @@
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/types.h>
+#include <uapi/linux/counter.h>
struct counter_device;
struct counter_count;
@@ -27,47 +28,6 @@ enum counter_comp_type {
COUNTER_COMP_COUNT_MODE,
};
-enum counter_scope {
- COUNTER_SCOPE_DEVICE,
- COUNTER_SCOPE_SIGNAL,
- COUNTER_SCOPE_COUNT,
-};
-
-enum counter_count_direction {
- COUNTER_COUNT_DIRECTION_FORWARD,
- COUNTER_COUNT_DIRECTION_BACKWARD,
-};
-
-enum counter_count_mode {
- COUNTER_COUNT_MODE_NORMAL,
- COUNTER_COUNT_MODE_RANGE_LIMIT,
- COUNTER_COUNT_MODE_NON_RECYCLE,
- COUNTER_COUNT_MODE_MODULO_N,
-};
-
-enum counter_function {
- COUNTER_FUNCTION_INCREASE,
- COUNTER_FUNCTION_DECREASE,
- COUNTER_FUNCTION_PULSE_DIRECTION,
- COUNTER_FUNCTION_QUADRATURE_X1_A,
- COUNTER_FUNCTION_QUADRATURE_X1_B,
- COUNTER_FUNCTION_QUADRATURE_X2_A,
- COUNTER_FUNCTION_QUADRATURE_X2_B,
- COUNTER_FUNCTION_QUADRATURE_X4,
-};
-
-enum counter_signal_level {
- COUNTER_SIGNAL_LEVEL_LOW,
- COUNTER_SIGNAL_LEVEL_HIGH,
-};
-
-enum counter_synapse_action {
- COUNTER_SYNAPSE_ACTION_NONE,
- COUNTER_SYNAPSE_ACTION_RISING_EDGE,
- COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
- COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
-};
-
/**
* struct counter_comp - Counter component node
* @type: Counter component data type
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
new file mode 100644
index 000000000000..6113938a6044
--- /dev/null
+++ b/include/uapi/linux/counter.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Userspace ABI for Counter character devices
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _UAPI_COUNTER_H_
+#define _UAPI_COUNTER_H_
+
+/* Component scope definitions */
+enum counter_scope {
+ COUNTER_SCOPE_DEVICE,
+ COUNTER_SCOPE_SIGNAL,
+ COUNTER_SCOPE_COUNT,
+};
+
+/* Count direction values */
+enum counter_count_direction {
+ COUNTER_COUNT_DIRECTION_FORWARD,
+ COUNTER_COUNT_DIRECTION_BACKWARD,
+};
+
+/* Count mode values */
+enum counter_count_mode {
+ COUNTER_COUNT_MODE_NORMAL,
+ COUNTER_COUNT_MODE_RANGE_LIMIT,
+ COUNTER_COUNT_MODE_NON_RECYCLE,
+ COUNTER_COUNT_MODE_MODULO_N,
+};
+
+/* Count function values */
+enum counter_function {
+ COUNTER_FUNCTION_INCREASE,
+ COUNTER_FUNCTION_DECREASE,
+ COUNTER_FUNCTION_PULSE_DIRECTION,
+ COUNTER_FUNCTION_QUADRATURE_X1_A,
+ COUNTER_FUNCTION_QUADRATURE_X1_B,
+ COUNTER_FUNCTION_QUADRATURE_X2_A,
+ COUNTER_FUNCTION_QUADRATURE_X2_B,
+ COUNTER_FUNCTION_QUADRATURE_X4,
+};
+
+/* Signal values */
+enum counter_signal_level {
+ COUNTER_SIGNAL_LEVEL_LOW,
+ COUNTER_SIGNAL_LEVEL_HIGH,
+};
+
+/* Action mode values */
+enum counter_synapse_action {
+ COUNTER_SYNAPSE_ACTION_NONE,
+ COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+ COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+ COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+#endif /* _UAPI_COUNTER_H_ */
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 07/14] counter: Add character device interface
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (4 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 06/14] counter: Move counter enums to uapi header William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-09-12 16:18 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 08/14] docs: counter: Document " William Breathitt Gray
` (8 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Dan Carpenter
This patch introduces a character device interface for the Counter
subsystem. Device data is exposed through standard character device read
operations. Device data is gathered when a Counter event is pushed by
the respective Counter device driver. Configuration is handled via ioctl
operations on the respective Counter character device node.
Cc: David Lechner <david@lechnology.com>
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/Makefile | 2 +-
drivers/counter/counter-chrdev.c | 553 +++++++++++++++++++++++++++++++
drivers/counter/counter-chrdev.h | 14 +
drivers/counter/counter-core.c | 60 +++-
include/linux/counter.h | 51 +++
include/uapi/linux/counter.h | 98 ++++++
6 files changed, 770 insertions(+), 8 deletions(-)
create mode 100644 drivers/counter/counter-chrdev.c
create mode 100644 drivers/counter/counter-chrdev.h
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 1ab7e087fdc2..8fde6c100ebc 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -4,7 +4,7 @@
#
obj-$(CONFIG_COUNTER) += counter.o
-counter-y := counter-core.o counter-sysfs.o
+counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
obj-$(CONFIG_INTERRUPT_CNT) += interrupt-cnt.o
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
new file mode 100644
index 000000000000..30659b67d8f3
--- /dev/null
+++ b/drivers/counter/counter-chrdev.c
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#include <linux/bitops.h>
+#include <linux/cdev.h>
+#include <linux/counter.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/kfifo.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/nospec.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+
+#include "counter-chrdev.h"
+
+struct counter_comp_node {
+ struct list_head l;
+ struct counter_component component;
+ struct counter_comp comp;
+ void *parent;
+};
+
+static ssize_t counter_chrdev_read(struct file *filp, char __user *buf,
+ size_t len, loff_t *f_ps)
+{
+ struct counter_device *const counter = filp->private_data;
+ int err;
+ unsigned int copied;
+
+ if (!counter->ops)
+ return -ENODEV;
+
+ if (len < sizeof(struct counter_event))
+ return -EINVAL;
+
+ do {
+ if (kfifo_is_empty(&counter->events)) {
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ err = wait_event_interruptible(counter->events_wait,
+ !kfifo_is_empty(&counter->events) ||
+ !counter->ops);
+ if (err < 0)
+ return err;
+ if (!counter->ops)
+ return -ENODEV;
+ }
+
+ if (mutex_lock_interruptible(&counter->events_lock))
+ return -ERESTARTSYS;
+ err = kfifo_to_user(&counter->events, buf, len, &copied);
+ mutex_unlock(&counter->events_lock);
+ if (err < 0)
+ return err;
+ } while (!copied);
+
+ return copied;
+}
+
+static __poll_t counter_chrdev_poll(struct file *filp,
+ struct poll_table_struct *pollt)
+{
+ struct counter_device *const counter = filp->private_data;
+ __poll_t events = 0;
+
+ if (!counter->ops)
+ return events;
+
+ poll_wait(filp, &counter->events_wait, pollt);
+
+ if (!kfifo_is_empty(&counter->events))
+ events = EPOLLIN | EPOLLRDNORM;
+
+ return events;
+}
+
+static void counter_events_list_free(struct list_head *const events_list)
+{
+ struct counter_event_node *p, *n;
+ struct counter_comp_node *q, *o;
+
+ list_for_each_entry_safe(p, n, events_list, l) {
+ /* Free associated component nodes */
+ list_for_each_entry_safe(q, o, &p->comp_list, l) {
+ list_del(&q->l);
+ kfree(q);
+ }
+
+ /* Free event node */
+ list_del(&p->l);
+ kfree(p);
+ }
+}
+
+static int counter_set_event_node(struct counter_device *const counter,
+ struct counter_watch *const watch,
+ const struct counter_comp_node *const cfg)
+{
+ struct counter_event_node *event_node;
+ int err = 0;
+ struct counter_comp_node *comp_node;
+
+ /* Search for event in the list */
+ list_for_each_entry(event_node, &counter->next_events_list, l)
+ if (event_node->event == watch->event &&
+ event_node->channel == watch->channel)
+ break;
+
+ /* If event is not already in the list */
+ if (&event_node->l == &counter->next_events_list) {
+ /* Allocate new event node */
+ event_node = kmalloc(sizeof(*event_node), GFP_KERNEL);
+ if (!event_node)
+ return -ENOMEM;
+
+ /* Configure event node and add to the list */
+ event_node->event = watch->event;
+ event_node->channel = watch->channel;
+ INIT_LIST_HEAD(&event_node->comp_list);
+ list_add(&event_node->l, &counter->next_events_list);
+ }
+
+ /* Check if component watch has already been set before */
+ list_for_each_entry(comp_node, &event_node->comp_list, l)
+ if (comp_node->parent == cfg->parent &&
+ comp_node->comp.count_u8_read == cfg->comp.count_u8_read) {
+ err = -EINVAL;
+ goto exit_free_event_node;
+ }
+
+ /* Allocate component node */
+ comp_node = kmalloc(sizeof(*comp_node), GFP_KERNEL);
+ if (!comp_node) {
+ err = -ENOMEM;
+ goto exit_free_event_node;
+ }
+ *comp_node = *cfg;
+
+ /* Add component node to event node */
+ list_add_tail(&comp_node->l, &event_node->comp_list);
+
+exit_free_event_node:
+ /* Free event node if no one else is watching */
+ if (list_empty(&event_node->comp_list)) {
+ list_del(&event_node->l);
+ kfree(event_node);
+ }
+
+ return err;
+}
+
+static int counter_enable_events(struct counter_device *const counter)
+{
+ unsigned long flags;
+ int err = 0;
+
+ mutex_lock(&counter->n_events_list_lock);
+ spin_lock_irqsave(&counter->events_list_lock, flags);
+
+ counter_events_list_free(&counter->events_list);
+ list_replace_init(&counter->next_events_list,
+ &counter->events_list);
+
+ if (counter->ops->events_configure)
+ err = counter->ops->events_configure(counter);
+
+ spin_unlock_irqrestore(&counter->events_list_lock, flags);
+ mutex_unlock(&counter->n_events_list_lock);
+
+ return err;
+}
+
+static int counter_disable_events(struct counter_device *const counter)
+{
+ unsigned long flags;
+ int err = 0;
+
+ spin_lock_irqsave(&counter->events_list_lock, flags);
+
+ counter_events_list_free(&counter->events_list);
+
+ if (counter->ops->events_configure)
+ err = counter->ops->events_configure(counter);
+
+ spin_unlock_irqrestore(&counter->events_list_lock, flags);
+
+ mutex_lock(&counter->n_events_list_lock);
+
+ counter_events_list_free(&counter->next_events_list);
+
+ mutex_unlock(&counter->n_events_list_lock);
+
+ return err;
+}
+
+static int counter_add_watch(struct counter_device *const counter,
+ const unsigned long arg)
+{
+ void __user *const uwatch = (void __user *)arg;
+ struct counter_watch watch;
+ struct counter_comp_node comp_node = {};
+ size_t parent, id;
+ struct counter_comp *ext;
+ size_t num_ext;
+ int err = 0;
+
+ if (copy_from_user(&watch, uwatch, sizeof(watch)))
+ return -EFAULT;
+
+ if (watch.component.type == COUNTER_COMPONENT_NONE)
+ goto no_component;
+
+ parent = watch.component.parent;
+
+ /* Configure parent component info for comp node */
+ switch (watch.component.scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ext = counter->ext;
+ num_ext = counter->num_ext;
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ if (parent >= counter->num_signals)
+ return -EINVAL;
+ parent = array_index_nospec(parent, counter->num_signals);
+
+ comp_node.parent = counter->signals + parent;
+
+ ext = counter->signals[parent].ext;
+ num_ext = counter->signals[parent].num_ext;
+ break;
+ case COUNTER_SCOPE_COUNT:
+ if (parent >= counter->num_counts)
+ return -EINVAL;
+ parent = array_index_nospec(parent, counter->num_counts);
+
+ comp_node.parent = counter->counts + parent;
+
+ ext = counter->counts[parent].ext;
+ num_ext = counter->counts[parent].num_ext;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ id = watch.component.id;
+
+ /* Configure component info for comp node */
+ switch (watch.component.type) {
+ case COUNTER_COMPONENT_SIGNAL:
+ if (watch.component.scope != COUNTER_SCOPE_SIGNAL)
+ return -EINVAL;
+
+ comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL;
+ comp_node.comp.signal_u32_read = counter->ops->signal_read;
+ break;
+ case COUNTER_COMPONENT_COUNT:
+ if (watch.component.scope != COUNTER_SCOPE_COUNT)
+ return -EINVAL;
+
+ comp_node.comp.type = COUNTER_COMP_U64;
+ comp_node.comp.count_u64_read = counter->ops->count_read;
+ break;
+ case COUNTER_COMPONENT_FUNCTION:
+ if (watch.component.scope != COUNTER_SCOPE_COUNT)
+ return -EINVAL;
+
+ comp_node.comp.type = COUNTER_COMP_FUNCTION;
+ comp_node.comp.count_u32_read = counter->ops->function_read;
+ break;
+ case COUNTER_COMPONENT_SYNAPSE_ACTION:
+ if (watch.component.scope != COUNTER_SCOPE_COUNT)
+ return -EINVAL;
+ if (id >= counter->counts[parent].num_synapses)
+ return -EINVAL;
+ id = array_index_nospec(id, counter->counts[parent].num_synapses);
+
+ comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION;
+ comp_node.comp.action_read = counter->ops->action_read;
+ comp_node.comp.priv = counter->counts[parent].synapses + id;
+ break;
+ case COUNTER_COMPONENT_EXTENSION:
+ if (id >= num_ext)
+ return -EINVAL;
+ id = array_index_nospec(id, num_ext);
+
+ comp_node.comp = ext[id];
+ break;
+ default:
+ return -EINVAL;
+ }
+ /* Check if any read callback is set; this is part of a union */
+ if (!comp_node.comp.count_u8_read)
+ return -EOPNOTSUPP;
+
+no_component:
+ mutex_lock(&counter->n_events_list_lock);
+
+ if (counter->ops->watch_validate) {
+ err = counter->ops->watch_validate(counter, &watch);
+ if (err < 0)
+ goto err_exit;
+ }
+
+ comp_node.component = watch.component;
+
+ err = counter_set_event_node(counter, &watch, &comp_node);
+
+err_exit:
+ mutex_unlock(&counter->n_events_list_lock);
+
+ return err;
+}
+
+static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct counter_device *const counter = filp->private_data;
+ int ret = -ENODEV;
+
+ mutex_lock(&counter->ops_exist_lock);
+
+ if (!counter->ops)
+ goto out_unlock;
+
+ switch (cmd) {
+ case COUNTER_ADD_WATCH_IOCTL:
+ ret = counter_add_watch(counter, arg);
+ break;
+ case COUNTER_ENABLE_EVENTS_IOCTL:
+ ret = counter_enable_events(counter);
+ break;
+ case COUNTER_DISABLE_EVENTS_IOCTL:
+ ret = counter_disable_events(counter);
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+
+out_unlock:
+ mutex_unlock(&counter->ops_exist_lock);
+
+ return ret;
+}
+
+static int counter_chrdev_open(struct inode *inode, struct file *filp)
+{
+ struct counter_device *const counter = container_of(inode->i_cdev,
+ typeof(*counter),
+ chrdev);
+
+ if (test_and_set_bit_lock(0, counter->chrdev_lock))
+ return -EBUSY;
+
+ get_device(&counter->dev);
+ filp->private_data = counter;
+
+ return nonseekable_open(inode, filp);
+}
+
+static int counter_chrdev_release(struct inode *inode, struct file *filp)
+{
+ struct counter_device *const counter = filp->private_data;
+ int ret = 0;
+
+ mutex_lock(&counter->ops_exist_lock);
+
+ if (!counter->ops) {
+ counter_events_list_free(&counter->events_list);
+ counter_events_list_free(&counter->next_events_list);
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ ret = counter_disable_events(counter);
+ if (ret < 0) {
+ mutex_unlock(&counter->ops_exist_lock);
+ return ret;
+ }
+
+out_unlock:
+ mutex_unlock(&counter->ops_exist_lock);
+
+ put_device(&counter->dev);
+ clear_bit_unlock(0, counter->chrdev_lock);
+
+ return ret;
+}
+
+static const struct file_operations counter_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = counter_chrdev_read,
+ .poll = counter_chrdev_poll,
+ .unlocked_ioctl = counter_chrdev_ioctl,
+ .open = counter_chrdev_open,
+ .release = counter_chrdev_release,
+};
+
+int counter_chrdev_add(struct counter_device *const counter)
+{
+ /* Initialize Counter events lists */
+ INIT_LIST_HEAD(&counter->events_list);
+ INIT_LIST_HEAD(&counter->next_events_list);
+ spin_lock_init(&counter->events_list_lock);
+ mutex_init(&counter->n_events_list_lock);
+ init_waitqueue_head(&counter->events_wait);
+ mutex_init(&counter->events_lock);
+
+ /* Initialize character device */
+ clear_bit(0, counter->chrdev_lock);
+ cdev_init(&counter->chrdev, &counter_fops);
+
+ /* Allocate Counter events queue */
+ return kfifo_alloc(&counter->events, 64, GFP_KERNEL);
+}
+
+void counter_chrdev_remove(struct counter_device *const counter)
+{
+ kfifo_free(&counter->events);
+}
+
+static int counter_get_data(struct counter_device *const counter,
+ const struct counter_comp_node *const comp_node,
+ u64 *const value)
+{
+ const struct counter_comp *const comp = &comp_node->comp;
+ void *const parent = comp_node->parent;
+ u8 value_u8 = 0;
+ u32 value_u32 = 0;
+ int ret;
+
+ if (comp_node->component.type == COUNTER_COMPONENT_NONE)
+ return 0;
+
+ switch (comp->type) {
+ case COUNTER_COMP_U8:
+ case COUNTER_COMP_BOOL:
+ switch (comp_node->component.scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ret = comp->device_u8_read(counter, &value_u8);
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ ret = comp->signal_u8_read(counter, parent, &value_u8);
+ break;
+ case COUNTER_SCOPE_COUNT:
+ ret = comp->count_u8_read(counter, parent, &value_u8);
+ break;
+ }
+ *value = value_u8;
+ return ret;
+ case COUNTER_COMP_SIGNAL_LEVEL:
+ case COUNTER_COMP_FUNCTION:
+ case COUNTER_COMP_ENUM:
+ case COUNTER_COMP_COUNT_DIRECTION:
+ case COUNTER_COMP_COUNT_MODE:
+ switch (comp_node->component.scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ret = comp->device_u32_read(counter, &value_u32);
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ ret = comp->signal_u32_read(counter, parent,
+ &value_u32);
+ break;
+ case COUNTER_SCOPE_COUNT:
+ ret = comp->count_u32_read(counter, parent, &value_u32);
+ break;
+ }
+ *value = value_u32;
+ return ret;
+ case COUNTER_COMP_U64:
+ switch (comp_node->component.scope) {
+ case COUNTER_SCOPE_DEVICE:
+ return comp->device_u64_read(counter, value);
+ case COUNTER_SCOPE_SIGNAL:
+ return comp->signal_u64_read(counter, parent, value);
+ case COUNTER_SCOPE_COUNT:
+ return comp->count_u64_read(counter, parent, value);
+ default:
+ return -EINVAL;
+ }
+ case COUNTER_COMP_SYNAPSE_ACTION:
+ ret = comp->action_read(counter, parent, comp->priv,
+ &value_u32);
+ *value = value_u32;
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * counter_push_event - queue event for userspace reading
+ * @counter: pointer to Counter structure
+ * @event: triggered event
+ * @channel: event channel
+ *
+ * Note: If no one is watching for the respective event, it is silently
+ * discarded.
+ */
+void counter_push_event(struct counter_device *const counter, const u8 event,
+ const u8 channel)
+{
+ struct counter_event ev;
+ unsigned int copied = 0;
+ unsigned long flags;
+ struct counter_event_node *event_node;
+ struct counter_comp_node *comp_node;
+
+ ev.timestamp = ktime_get_ns();
+ ev.watch.event = event;
+ ev.watch.channel = channel;
+
+ /* Could be in an interrupt context, so use a spin lock */
+ spin_lock_irqsave(&counter->events_list_lock, flags);
+
+ /* Search for event in the list */
+ list_for_each_entry(event_node, &counter->events_list, l)
+ if (event_node->event == event &&
+ event_node->channel == channel)
+ break;
+
+ /* If event is not in the list */
+ if (&event_node->l == &counter->events_list)
+ goto exit_early;
+
+ /* Read and queue relevant comp for userspace */
+ list_for_each_entry(comp_node, &event_node->comp_list, l) {
+ ev.watch.component = comp_node->component;
+ ev.status = -counter_get_data(counter, comp_node, &ev.value);
+
+ copied += kfifo_in(&counter->events, &ev, 1);
+ }
+
+exit_early:
+ spin_unlock_irqrestore(&counter->events_list_lock, flags);
+
+ if (copied)
+ wake_up_poll(&counter->events_wait, EPOLLIN);
+}
+EXPORT_SYMBOL_GPL(counter_push_event);
diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
new file mode 100644
index 000000000000..5529d16703c4
--- /dev/null
+++ b/drivers/counter/counter-chrdev.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _COUNTER_CHRDEV_H_
+#define _COUNTER_CHRDEV_H_
+
+#include <linux/counter.h>
+
+int counter_chrdev_add(struct counter_device *const counter);
+void counter_chrdev_remove(struct counter_device *const counter);
+
+#endif /* _COUNTER_CHRDEV_H_ */
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
index 3cda2c47bacb..28dc1ff63c94 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -3,14 +3,22 @@
* Generic Counter interface
* Copyright (C) 2020 William Breathitt Gray
*/
+#include <linux/cdev.h>
#include <linux/counter.h>
#include <linux/device.h>
+#include <linux/device/bus.h>
#include <linux/export.h>
+#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/init.h>
+#include <linux/kdev_t.h>
#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include "counter-chrdev.h"
#include "counter-sysfs.h"
/* Provides a unique ID for each counter device */
@@ -18,6 +26,9 @@ static DEFINE_IDA(counter_ida);
static void counter_device_release(struct device *dev)
{
+ struct counter_device *const counter = dev_get_drvdata(dev);
+
+ counter_chrdev_remove(counter);
ida_free(&counter_ida, dev->id);
}
@@ -31,6 +42,8 @@ static struct bus_type counter_bus_type = {
.dev_name = "counter",
};
+static dev_t counter_devt;
+
/**
* counter_register - register Counter to the system
* @counter: pointer to Counter to register
@@ -53,10 +66,13 @@ int counter_register(struct counter_device *const counter)
if (id < 0)
return id;
+ mutex_init(&counter->ops_exist_lock);
+
/* Configure device structure for Counter */
dev->id = id;
dev->type = &counter_device_type;
dev->bus = &counter_bus_type;
+ dev->devt = MKDEV(MAJOR(counter_devt), id);
if (counter->parent) {
dev->parent = counter->parent;
dev->of_node = counter->parent->of_node;
@@ -64,18 +80,22 @@ int counter_register(struct counter_device *const counter)
device_initialize(dev);
dev_set_drvdata(dev, counter);
- /* Add Counter sysfs attributes */
- err = counter_sysfs_add(counter);
+ err = counter_chrdev_add(counter);
if (err < 0)
goto err_free_id;
- /* Add device to system */
- err = device_add(dev);
+ err = counter_sysfs_add(counter);
if (err < 0)
- goto err_free_id;
+ goto err_remove_chrdev;
+
+ err = cdev_device_add(&counter->chrdev, dev);
+ if (err < 0)
+ goto err_remove_chrdev;
return 0;
+err_remove_chrdev:
+ counter_chrdev_remove(counter);
err_free_id:
put_device(dev);
return err;
@@ -93,7 +113,16 @@ void counter_unregister(struct counter_device *const counter)
if (!counter)
return;
- device_unregister(&counter->dev);
+ cdev_device_del(&counter->chrdev, &counter->dev);
+
+ mutex_lock(&counter->ops_exist_lock);
+
+ counter->ops = NULL;
+ wake_up(&counter->events_wait);
+
+ mutex_unlock(&counter->ops_exist_lock);
+
+ put_device(&counter->dev);
}
EXPORT_SYMBOL_GPL(counter_unregister);
@@ -127,13 +156,30 @@ int devm_counter_register(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_counter_register);
+#define COUNTER_DEV_MAX 256
+
static int __init counter_init(void)
{
- return bus_register(&counter_bus_type);
+ int err;
+
+ err = bus_register(&counter_bus_type);
+ if (err < 0)
+ return err;
+
+ err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
+ if (err < 0)
+ goto err_unregister_bus;
+
+ return 0;
+
+err_unregister_bus:
+ bus_unregister(&counter_bus_type);
+ return err;
}
static void __exit counter_exit(void)
{
+ unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
bus_unregister(&counter_bus_type);
}
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 7c9f7e23953a..9c9984655f8c 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -6,9 +6,14 @@
#ifndef _COUNTER_H_
#define _COUNTER_H_
+#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/mutex.h>
+#include <linux/spinlock_types.h>
#include <linux/types.h>
+#include <linux/wait.h>
#include <uapi/linux/counter.h>
struct counter_device;
@@ -199,6 +204,20 @@ struct counter_count {
size_t num_ext;
};
+/**
+ * struct counter_event_node - Counter Event node
+ * @l: list of current watching Counter events
+ * @event: event that triggers
+ * @channel: event channel
+ * @comp_list: list of components to watch when event triggers
+ */
+struct counter_event_node {
+ struct list_head l;
+ u8 event;
+ u8 channel;
+ struct list_head comp_list;
+};
+
/**
* struct counter_ops - Callbacks from driver
* @signal_read: optional read callback for Signals. The read level of
@@ -222,6 +241,13 @@ struct counter_count {
* @action_write: optional write callback for Synapse action modes. The
* action mode to write for the respective Synapse is
* passed in via the action parameter.
+ * @events_configure: optional write callback to configure events. The list of
+ * struct counter_event_node may be accessed via the
+ * events_list member of the counter parameter.
+ * @watch_validate: optional callback to validate a watch. The Counter
+ * component watch configuration is passed in via the watch
+ * parameter. A return value of 0 indicates a valid Counter
+ * component watch configuration.
*/
struct counter_ops {
int (*signal_read)(struct counter_device *counter,
@@ -245,6 +271,9 @@ struct counter_ops {
struct counter_count *count,
struct counter_synapse *synapse,
enum counter_synapse_action action);
+ int (*events_configure)(struct counter_device *counter);
+ int (*watch_validate)(struct counter_device *counter,
+ const struct counter_watch *watch);
};
/**
@@ -260,6 +289,16 @@ struct counter_ops {
* @num_ext: number of Counter device extensions specified in @ext
* @priv: optional private data supplied by driver
* @dev: internal device structure
+ * @chrdev: internal character device structure
+ * @events_list: list of current watching Counter events
+ * @events_list_lock: lock to protect Counter events list operations
+ * @next_events_list: list of next watching Counter events
+ * @n_events_list_lock: lock to protect Counter next events list operations
+ * @events: queue of detected Counter events
+ * @events_wait: wait queue to allow blocking reads of Counter events
+ * @events_lock: lock to protect Counter events queue read operations
+ * @chrdev_lock: lock to limit chrdev to a single open at a time
+ * @ops_exist_lock: lock to prevent use during removal
*/
struct counter_device {
const char *name;
@@ -278,12 +317,24 @@ struct counter_device {
void *priv;
struct device dev;
+ struct cdev chrdev;
+ struct list_head events_list;
+ spinlock_t events_list_lock;
+ struct list_head next_events_list;
+ struct mutex n_events_list_lock;
+ DECLARE_KFIFO_PTR(events, struct counter_event);
+ wait_queue_head_t events_wait;
+ struct mutex events_lock;
+ DECLARE_BITMAP(chrdev_lock, 1);
+ struct mutex ops_exist_lock;
};
int counter_register(struct counter_device *const counter);
void counter_unregister(struct counter_device *const counter);
int devm_counter_register(struct device *dev,
struct counter_device *const counter);
+void counter_push_event(struct counter_device *const counter, const u8 event,
+ const u8 channel);
#define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \
{ \
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
index 6113938a6044..d0aa95aeff7b 100644
--- a/include/uapi/linux/counter.h
+++ b/include/uapi/linux/counter.h
@@ -6,6 +6,19 @@
#ifndef _UAPI_COUNTER_H_
#define _UAPI_COUNTER_H_
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/* Component type definitions */
+enum counter_component_type {
+ COUNTER_COMPONENT_NONE,
+ COUNTER_COMPONENT_SIGNAL,
+ COUNTER_COMPONENT_COUNT,
+ COUNTER_COMPONENT_FUNCTION,
+ COUNTER_COMPONENT_SYNAPSE_ACTION,
+ COUNTER_COMPONENT_EXTENSION,
+};
+
/* Component scope definitions */
enum counter_scope {
COUNTER_SCOPE_DEVICE,
@@ -13,6 +26,91 @@ enum counter_scope {
COUNTER_SCOPE_COUNT,
};
+/**
+ * struct counter_component - Counter component identification
+ * @type: component type (one of enum counter_component_type)
+ * @scope: component scope (one of enum counter_scope)
+ * @parent: parent ID (matching the ID suffix of the respective parent sysfs
+ * path as described by the ABI documentation file
+ * Documentation/ABI/testing/sysfs-bus-counter)
+ * @id: component ID (matching the ID provided by the respective *_component_id
+ * sysfs attribute of the desired component)
+ *
+ * For example, if the Count 2 ceiling extension of Counter device 4 is desired,
+ * set type equal to COUNTER_COMPONENT_EXTENSION, scope equal to
+ * COUNTER_COUNT_SCOPE, parent equal to 2, and id equal to the value provided by
+ * the respective /sys/bus/counter/devices/counter4/count2/ceiling_component_id
+ * sysfs attribute.
+ */
+struct counter_component {
+ __u8 type;
+ __u8 scope;
+ __u8 parent;
+ __u8 id;
+};
+
+/* Event type definitions */
+enum counter_event_type {
+ /* Count value increased past ceiling */
+ COUNTER_EVENT_OVERFLOW,
+ /* Count value decreased past floor */
+ COUNTER_EVENT_UNDERFLOW,
+ /* Count value increased past ceiling, or decreased past floor */
+ COUNTER_EVENT_OVERFLOW_UNDERFLOW,
+ /* Count value reached threshold */
+ COUNTER_EVENT_THRESHOLD,
+ /* Index signal detected */
+ COUNTER_EVENT_INDEX,
+};
+
+/**
+ * struct counter_watch - Counter component watch configuration
+ * @component: component to watch when event triggers
+ * @event: event that triggers (one of enum counter_event_type)
+ * @channel: event channel (typically 0 unless the device supports concurrent
+ * events of the same type)
+ */
+struct counter_watch {
+ struct counter_component component;
+ __u8 event;
+ __u8 channel;
+};
+
+/*
+ * Queues a Counter watch for the specified event.
+ *
+ * The queued watches will not be applied until COUNTER_ENABLE_EVENTS_IOCTL is
+ * called.
+ */
+#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
+/*
+ * Enables monitoring the events specified by the Counter watches that were
+ * queued by COUNTER_ADD_WATCH_IOCTL.
+ *
+ * If events are already enabled, the new set of watches replaces the old one.
+ * Calling this ioctl also has the effect of clearing the queue of watches added
+ * by COUNTER_ADD_WATCH_IOCTL.
+ */
+#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
+/*
+ * Stops monitoring the previously enabled events.
+ */
+#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
+
+/**
+ * struct counter_event - Counter event data
+ * @timestamp: best estimate of time of event occurrence, in nanoseconds
+ * @value: component value
+ * @watch: component watch configuration
+ * @status: return status (system error number)
+ */
+struct counter_event {
+ __aligned_u64 timestamp;
+ __aligned_u64 value;
+ struct counter_watch watch;
+ __u8 status;
+};
+
/* Count direction values */
enum counter_count_direction {
COUNTER_COUNT_DIRECTION_FORWARD,
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 08/14] docs: counter: Document character device interface
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (5 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 07/14] counter: Add character device interface William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-09-12 16:18 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 09/14] tools/counter: Create Counter tools William Breathitt Gray
` (7 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
This patch adds high-level documentation about the Counter subsystem
character device interface.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Documentation/driver-api/generic-counter.rst | 177 ++++++++++++++----
.../userspace-api/ioctl/ioctl-number.rst | 1 +
2 files changed, 137 insertions(+), 41 deletions(-)
diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index f6397218aa4c..6ecb5d1942c7 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -223,19 +223,6 @@ whether an input line is differential or single-ended) and instead focus
on the core idea of what the data and process represent (e.g. position
as interpreted from quadrature encoding data).
-Userspace Interface
-===================
-
-Several sysfs attributes are generated by the Generic Counter interface,
-and reside under the /sys/bus/counter/devices/counterX directory, where
-counterX refers to the respective counter device. Please see
-Documentation/ABI/testing/sysfs-bus-counter for detailed
-information on each Generic Counter interface sysfs attribute.
-
-Through these sysfs attributes, programs and scripts may interact with
-the Generic Counter paradigm Counts, Signals, and Synapses of respective
-counter devices.
-
Driver API
==========
@@ -388,16 +375,16 @@ userspace interface components::
/ driver callbacks /
-------------------
|
- +---------------+
- |
- V
- +--------------------+
- | Counter sysfs |
- +--------------------+
- | Translates to the |
- | standard Counter |
- | sysfs output |
- +--------------------+
+ +---------------+---------------+
+ | |
+ V V
+ +--------------------+ +---------------------+
+ | Counter sysfs | | Counter chrdev |
+ +--------------------+ +---------------------+
+ | Translates to the | | Translates to the |
+ | standard Counter | | standard Counter |
+ | sysfs output | | character device |
+ +--------------------+ +---------------------+
Thereafter, data can be transferred directly between the Counter device
driver and Counter userspace interface::
@@ -428,23 +415,30 @@ driver and Counter userspace interface::
/ u64 /
----------
|
- +---------------+
- |
- V
- +--------------------+
- | Counter sysfs |
- +--------------------+
- | Translates to the |
- | standard Counter |
- | sysfs output |
- |--------------------|
- | Type: const char * |
- | Value: "42" |
- +--------------------+
- |
- ---------------
- / const char * /
- ---------------
+ +---------------+---------------+
+ | |
+ V V
+ +--------------------+ +---------------------+
+ | Counter sysfs | | Counter chrdev |
+ +--------------------+ +---------------------+
+ | Translates to the | | Translates to the |
+ | standard Counter | | standard Counter |
+ | sysfs output | | character device |
+ |--------------------| |---------------------|
+ | Type: const char * | | Type: u64 |
+ | Value: "42" | | Value: 42 |
+ +--------------------+ +---------------------+
+ | |
+ --------------- -----------------------
+ / const char * / / struct counter_event /
+ --------------- -----------------------
+ | |
+ | V
+ | +-----------+
+ | | read |
+ | +-----------+
+ | \ Count: 42 /
+ | -----------
|
V
+--------------------------------------------------+
@@ -453,7 +447,7 @@ driver and Counter userspace interface::
\ Count: "42" /
--------------------------------------------------
-There are three primary components involved:
+There are four primary components involved:
Counter device driver
---------------------
@@ -473,3 +467,104 @@ and vice versa.
Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
for a detailed breakdown of the available Generic Counter interface
sysfs attributes.
+
+Counter chrdev
+--------------
+Translates counter data to the standard Counter character device; data
+is transferred via standard character device read calls, while Counter
+events are configured via ioctl calls.
+
+Sysfs Interface
+===============
+
+Several sysfs attributes are generated by the Generic Counter interface,
+and reside under the ``/sys/bus/counter/devices/counterX`` directory,
+where ``X`` is to the respective counter device id. Please see
+``Documentation/ABI/testing/sysfs-bus-counter`` for detailed information
+on each Generic Counter interface sysfs attribute.
+
+Through these sysfs attributes, programs and scripts may interact with
+the Generic Counter paradigm Counts, Signals, and Synapses of respective
+counter devices.
+
+Counter Character Device
+========================
+
+Counter character device nodes are created under the ``/dev`` directory
+as ``counterX``, where ``X`` is the respective counter device id.
+Defines for the standard Counter data types are exposed via the
+userspace ``include/uapi/linux/counter.h`` file.
+
+Counter events
+--------------
+Counter device drivers can support Counter events by utilizing the
+``counter_push_event`` function::
+
+ void counter_push_event(struct counter_device *const counter, const u8 event,
+ const u8 channel);
+
+The event id is specified by the ``event`` parameter; the event channel
+id is specified by the ``channel`` parameter. When this function is
+called, the Counter data associated with the respective event is
+gathered, and a ``struct counter_event`` is generated for each datum and
+pushed to userspace.
+
+Counter events can be configured by users to report various Counter
+data of interest. This can be conceptualized as a list of Counter
+component read calls to perform. For example:
+
+ +------------------------+------------------------+
+ | COUNTER_EVENT_OVERFLOW | COUNTER_EVENT_INDEX |
+ +========================+========================+
+ | Channel 0 | Channel 0 |
+ +------------------------+------------------------+
+ | * Count 0 | * Signal 0 |
+ | * Count 1 | * Signal 0 Extension 0 |
+ | * Signal 3 | * Extension 4 |
+ | * Count 4 Extension 2 +------------------------+
+ | * Signal 5 Extension 0 | Channel 1 |
+ | +------------------------+
+ | | * Signal 4 |
+ | | * Signal 4 Extension 0 |
+ | | * Count 7 |
+ +------------------------+------------------------+
+
+When ``counter_push_event(counter, COUNTER_EVENT_INDEX, 1)`` is called
+for example, it will go down the list for the ``COUNTER_EVENT_INDEX``
+event channel 1 and execute the read callbacks for Signal 4, Signal 4
+Extension 0, and Count 7 -- the data returned for each is pushed to a
+kfifo as a ``struct counter_event``, which userspace can retrieve via a
+standard read operation on the respective character device node.
+
+Userspace
+---------
+Userspace applications can configure Counter events via ioctl operations
+on the Counter character device node. There following ioctl codes are
+supported and provided by the ``linux/counter.h`` userspace header file:
+
+* :c:macro:`COUNTER_ADD_WATCH_IOCTL`
+
+* :c:macro:`COUNTER_ENABLE_EVENTS_IOCTL`
+
+* :c:macro:`COUNTER_DISABLE_EVENTS_IOCTL`
+
+To configure events to gather Counter data, users first populate a
+``struct counter_watch`` with the relevant event id, event channel id,
+and the information for the desired Counter component from which to
+read, and then pass it via the ``COUNTER_ADD_WATCH_IOCTL`` ioctl
+command.
+
+Note that an event can be watched without gathering Counter data by
+setting the ``component.type`` member equal to
+``COUNTER_COMPONENT_NONE``. With this configuration the Counter
+character device will simply populate the event timestamps for those
+respective ``struct counter_event`` elements and ignore the component
+value.
+
+The ``COUNTER_ADD_WATCH_IOCTL`` command will buffer these Counter
+watches. When ready, the ``COUNTER_ENABLE_EVENTS_IOCTL`` ioctl command
+may be used to activate these Counter watches.
+
+Userspace applications can then execute a ``read`` operation (optionally
+calling ``poll`` first) on the Counter character device node to retrieve
+``struct counter_event`` elements with the desired data.
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 1409e40e6345..fc4ccc79b1b8 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -88,6 +88,7 @@ Code Seq# Include File Comments
<http://infiniband.sourceforge.net/>
0x20 all drivers/cdrom/cm206.h
0x22 all scsi/sg.h
+0x3E 00-0F linux/counter.h <mailto:linux-iio@vger.kernel.org>
'!' 00-1F uapi/linux/seccomp.h
'#' 00-3F IEEE 1394 Subsystem
Block for the entire subsystem
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 09/14] tools/counter: Create Counter tools
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (6 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 08/14] docs: counter: Document " William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-09-12 16:26 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 10/14] counter: Implement signalZ_action_component_id sysfs attribute William Breathitt Gray
` (6 subsequent siblings)
14 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Pavel Machek
This creates an example Counter program under tools/counter/*
to exemplify the Counter character device interface.
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
MAINTAINERS | 1 +
tools/Makefile | 13 ++---
tools/counter/Build | 1 +
tools/counter/Makefile | 53 +++++++++++++++++++
tools/counter/counter_example.c | 93 +++++++++++++++++++++++++++++++++
5 files changed, 155 insertions(+), 6 deletions(-)
create mode 100644 tools/counter/Build
create mode 100644 tools/counter/Makefile
create mode 100644 tools/counter/counter_example.c
diff --git a/MAINTAINERS b/MAINTAINERS
index f2fdd2202605..57dc9b6ff82a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4782,6 +4782,7 @@ F: Documentation/driver-api/generic-counter.rst
F: drivers/counter/
F: include/linux/counter.h
F: include/uapi/linux/counter.h
+F: tools/counter/
CP2615 I2C DRIVER
M: Bence Csókás <bence98@sch.bme.hu>
diff --git a/tools/Makefile b/tools/Makefile
index 7e9d34ddd74c..5da1fde03a9a 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -12,6 +12,7 @@ help:
@echo ' acpi - ACPI tools'
@echo ' bpf - misc BPF tools'
@echo ' cgroup - cgroup tools'
+ @echo ' counter - counter tools'
@echo ' cpupower - a tool for all things x86 CPU power'
@echo ' debugging - tools for debugging'
@echo ' firewire - the userspace part of nosy, an IEEE-1394 traffic sniffer'
@@ -65,7 +66,7 @@ acpi: FORCE
cpupower: FORCE
$(call descend,power/$@)
-cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
+cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
$(call descend,$@)
bpf/%: FORCE
@@ -100,7 +101,7 @@ freefall: FORCE
kvm_stat: FORCE
$(call descend,kvm/$@)
-all: acpi cgroup cpupower gpio hv firewire liblockdep \
+all: acpi cgroup counter cpupower gpio hv firewire liblockdep \
perf selftests bootconfig spi turbostat usb \
virtio vm bpf x86_energy_perf_policy \
tmon freefall iio objtool kvm_stat wmi \
@@ -112,7 +113,7 @@ acpi_install:
cpupower_install:
$(call descend,power/$(@:_install=),install)
-cgroup_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
+cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
$(call descend,$(@:_install=),install)
liblockdep_install:
@@ -133,7 +134,7 @@ freefall_install:
kvm_stat_install:
$(call descend,kvm/$(@:_install=),install)
-install: acpi_install cgroup_install cpupower_install gpio_install \
+install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
hv_install firewire_install iio_install liblockdep_install \
perf_install selftests_install turbostat_install usb_install \
virtio_install vm_install bpf_install x86_energy_perf_policy_install \
@@ -147,7 +148,7 @@ acpi_clean:
cpupower_clean:
$(call descend,power/cpupower,clean)
-cgroup_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
+cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
$(call descend,$(@:_clean=),clean)
liblockdep_clean:
@@ -181,7 +182,7 @@ freefall_clean:
build_clean:
$(call descend,build,clean)
-clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean \
+clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
diff --git a/tools/counter/Build b/tools/counter/Build
new file mode 100644
index 000000000000..33f4a51d715e
--- /dev/null
+++ b/tools/counter/Build
@@ -0,0 +1 @@
+counter_example-y += counter_example.o
diff --git a/tools/counter/Makefile b/tools/counter/Makefile
new file mode 100644
index 000000000000..5ebc195fd9c0
--- /dev/null
+++ b/tools/counter/Makefile
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../scripts/Makefile.include
+
+bindir ?= /usr/bin
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+# Do not use make's built-in rules
+# (this improves performance and avoids hard-to-debug behaviour);
+MAKEFLAGS += -r
+
+override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+
+ALL_TARGETS := counter_example
+ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
+
+all: $(ALL_PROGRAMS)
+
+export srctree OUTPUT CC LD CFLAGS
+include $(srctree)/tools/build/Makefile.include
+
+#
+# We need the following to be outside of kernel tree
+#
+$(OUTPUT)include/linux/counter.h: ../../include/uapi/linux/counter.h
+ mkdir -p $(OUTPUT)include/linux 2>&1 || true
+ ln -sf $(CURDIR)/../../include/uapi/linux/counter.h $@
+
+prepare: $(OUTPUT)include/linux/counter.h
+
+COUNTER_EXAMPLE := $(OUTPUT)counter_example.o
+$(COUNTER_EXAMPLE): prepare FORCE
+ $(Q)$(MAKE) $(build)=counter_example
+$(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
+ $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+clean:
+ rm -f $(ALL_PROGRAMS)
+ rm -rf $(OUTPUT)include/linux/counter.h
+ find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+
+install: $(ALL_PROGRAMS)
+ install -d -m 755 $(DESTDIR)$(bindir); \
+ for program in $(ALL_PROGRAMS); do \
+ install $$program $(DESTDIR)$(bindir); \
+ done
+
+FORCE:
+
+.PHONY: all install clean FORCE prepare
diff --git a/tools/counter/counter_example.c b/tools/counter/counter_example.c
new file mode 100644
index 000000000000..90d69fb9463b
--- /dev/null
+++ b/tools/counter/counter_example.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Counter - example userspace application
+ *
+ * The userspace application opens /dev/counter0, configures the
+ * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count
+ * 1 count, and prints out the data as it becomes available on the
+ * character device node.
+ *
+ * Copyright (C) 2021 William Breathitt Gray
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/counter.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+static struct counter_watch watches[2] = {
+ {
+ /* Component data: Count 0 count */
+ .component.type = COUNTER_COMPONENT_COUNT,
+ .component.scope = COUNTER_SCOPE_COUNT,
+ .component.parent = 0,
+ /* Event type: Index */
+ .event = COUNTER_EVENT_INDEX,
+ /* Device event channel 0 */
+ .channel = 0,
+ },
+ {
+ /* Component data: Count 1 count */
+ .component.type = COUNTER_COMPONENT_COUNT,
+ .component.scope = COUNTER_SCOPE_COUNT,
+ .component.parent = 1,
+ /* Event type: Index */
+ .event = COUNTER_EVENT_INDEX,
+ /* Device event channel 0 */
+ .channel = 0,
+ },
+};
+
+int main(void)
+{
+ int fd;
+ int ret;
+ struct counter_event event_data[2];
+
+ fd = open("/dev/counter0", O_RDWR);
+ if (fd == -1) {
+ perror("Unable to open /dev/counter0");
+ return -errno;
+ }
+
+ ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
+ if (ret == -1) {
+ perror("Error adding watches[0]");
+ return -errno;
+ }
+ ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
+ if (ret == -1) {
+ perror("Error adding watches[1]");
+ return -errno;
+ }
+ ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
+ if (ret == -1) {
+ perror("Error enabling events");
+ return -errno;
+ }
+
+ for (;;) {
+ ret = read(fd, event_data, sizeof(event_data));
+ if (ret == -1) {
+ perror("Failed to read event data");
+ return 1;
+ }
+
+ if (ret != sizeof(event_data)) {
+ fprintf(stderr, "Failed to read event data\n");
+ return -EIO;
+ }
+
+ printf("Timestamp 0: %llu\tCount 0: %llu\n"
+ "Error Message 0: %s\n"
+ "Timestamp 1: %llu\tCount 1: %llu\n"
+ "Error Message 1: %s\n",
+ event_data[0].timestamp, event_data[0].value,
+ strerror(event_data[0].status),
+ event_data[1].timestamp, event_data[1].value,
+ strerror(event_data[1].status));
+ }
+
+ return 0;
+}
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 10/14] counter: Implement signalZ_action_component_id sysfs attribute
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (7 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 09/14] tools/counter: Create Counter tools William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 11/14] counter: Implement *_component_id sysfs attributes William Breathitt Gray
` (5 subsequent siblings)
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Dan Carpenter
The Generic Counter chrdev interface expects users to supply component
IDs in order to select Synapses for requests. In order for users to know
what component ID belongs to which Synapse this information must be
exposed. The signalZ_action_component_id attribute provides a way for
users to discover what component ID belongs to the respective Synapse.
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Documentation/ABI/testing/sysfs-bus-counter | 7 ++++
drivers/counter/counter-sysfs.c | 45 +++++++++++++++++++++
2 files changed, 52 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index dee79b606847..aa2cd3c10d74 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -203,6 +203,13 @@ Description:
both edges:
Any state transition.
+What: /sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
+KernelVersion: 5.16
+Contact: linux-iio@vger.kernel.org
+Description:
+ Read-only attribute that indicates the component ID of the
+ respective Synapse of Count Y for Signal Z.
+
What: /sys/bus/counter/devices/counterX/countY/spike_filter_ns
KernelVersion: 5.14
Contact: linux-iio@vger.kernel.org
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 108cbd838eb9..ee7ff1cde454 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -532,6 +532,46 @@ static int counter_name_attr_create(struct device *const dev,
return 0;
}
+static ssize_t counter_comp_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const size_t id = (size_t)to_counter_attribute(attr)->comp.priv;
+
+ return sprintf(buf, "%zu\n", id);
+}
+
+static int counter_comp_id_attr_create(struct device *const dev,
+ struct counter_attribute_group *const group,
+ const char *name, const size_t id)
+{
+ struct counter_attribute *counter_attr;
+
+ /* Allocate Counter attribute */
+ counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
+ if (!counter_attr)
+ return -ENOMEM;
+
+ /* Generate component ID name */
+ name = devm_kasprintf(dev, GFP_KERNEL, "%s_component_id", name);
+ if (!name)
+ return -ENOMEM;
+
+ /* Configure Counter attribute */
+ counter_attr->comp.priv = (void *)id;
+
+ /* Configure device attribute */
+ sysfs_attr_init(&counter_attr->dev_attr.attr);
+ counter_attr->dev_attr.attr.name = name;
+ counter_attr->dev_attr.attr.mode = 0444;
+ counter_attr->dev_attr.show = counter_comp_id_show;
+
+ /* Store list node */
+ list_add(&counter_attr->l, &group->attr_list);
+ group->num_attr++;
+
+ return 0;
+}
+
static struct counter_comp counter_signal_comp = {
.type = COUNTER_COMP_SIGNAL_LEVEL,
.name = "signal",
@@ -626,6 +666,11 @@ static int counter_sysfs_synapses_add(struct counter_device *const counter,
COUNTER_SCOPE_COUNT, count);
if (err < 0)
return err;
+
+ /* Create Synapse component ID attribute */
+ err = counter_comp_id_attr_create(dev, group, comp.name, i);
+ if (err < 0)
+ return err;
}
return 0;
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 11/14] counter: Implement *_component_id sysfs attributes
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (8 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 10/14] counter: Implement signalZ_action_component_id sysfs attribute William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 12/14] counter: Implement events_queue_size sysfs attribute William Breathitt Gray
` (4 subsequent siblings)
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray, Dan Carpenter
The Generic Counter chrdev interface expects users to supply component
IDs in order to select extensions for requests. In order for users to
know what component ID belongs to which extension this information must
be exposed. The *_component_id attribute provides a way for users to
discover what component ID belongs to which respective extension.
Cc: David Lechner <david@lechnology.com>
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Documentation/ABI/testing/sysfs-bus-counter | 16 +++++++++-
drivers/counter/counter-sysfs.c | 33 +++++++++++++++++----
2 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index aa2cd3c10d74..0ce16669157e 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -203,12 +203,26 @@ Description:
both edges:
Any state transition.
+What: /sys/bus/counter/devices/counterX/countY/ceiling_component_id
+What: /sys/bus/counter/devices/counterX/countY/floor_component_id
+What: /sys/bus/counter/devices/counterX/countY/count_mode_component_id
+What: /sys/bus/counter/devices/counterX/countY/direction_component_id
+What: /sys/bus/counter/devices/counterX/countY/enable_component_id
+What: /sys/bus/counter/devices/counterX/countY/error_noise_component_id
+What: /sys/bus/counter/devices/counterX/countY/prescaler_component_id
+What: /sys/bus/counter/devices/counterX/countY/preset_component_id
+What: /sys/bus/counter/devices/counterX/countY/preset_enable_component_id
What: /sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
+What: /sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
+What: /sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
+What: /sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
+What: /sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
+What: /sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
KernelVersion: 5.16
Contact: linux-iio@vger.kernel.org
Description:
Read-only attribute that indicates the component ID of the
- respective Synapse of Count Y for Signal Z.
+ respective extension or Synapse.
What: /sys/bus/counter/devices/counterX/countY/spike_filter_ns
KernelVersion: 5.14
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index ee7ff1cde454..97d8d7c2a2b6 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -586,6 +586,7 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
int err;
struct counter_comp comp;
size_t i;
+ struct counter_comp *ext;
/* Create main Signal attribute */
comp = counter_signal_comp;
@@ -601,8 +602,14 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
/* Create an attribute for each extension */
for (i = 0; i < signal->num_ext; i++) {
- err = counter_attr_create(dev, cattr_group, signal->ext + i,
- scope, signal);
+ ext = &signal->ext[i];
+
+ err = counter_attr_create(dev, cattr_group, ext, scope, signal);
+ if (err < 0)
+ return err;
+
+ err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
+ i);
if (err < 0)
return err;
}
@@ -693,6 +700,7 @@ static int counter_count_attrs_create(struct counter_device *const counter,
int err;
struct counter_comp comp;
size_t i;
+ struct counter_comp *ext;
/* Create main Count attribute */
comp = counter_count_comp;
@@ -717,8 +725,14 @@ static int counter_count_attrs_create(struct counter_device *const counter,
/* Create an attribute for each extension */
for (i = 0; i < count->num_ext; i++) {
- err = counter_attr_create(dev, cattr_group, count->ext + i,
- scope, count);
+ ext = &count->ext[i];
+
+ err = counter_attr_create(dev, cattr_group, ext, scope, count);
+ if (err < 0)
+ return err;
+
+ err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
+ i);
if (err < 0)
return err;
}
@@ -782,6 +796,7 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
struct device *const dev = &counter->dev;
int err;
size_t i;
+ struct counter_comp *ext;
/* Add Signals sysfs attributes */
err = counter_sysfs_signals_add(counter, cattr_group);
@@ -814,8 +829,14 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
/* Create an attribute for each extension */
for (i = 0; i < counter->num_ext; i++) {
- err = counter_attr_create(dev, cattr_group, counter->ext + i,
- scope, NULL);
+ ext = &counter->ext[i];
+
+ err = counter_attr_create(dev, cattr_group, ext, scope, NULL);
+ if (err < 0)
+ return err;
+
+ err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
+ i);
if (err < 0)
return err;
}
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 12/14] counter: Implement events_queue_size sysfs attribute
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (9 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 11/14] counter: Implement *_component_id sysfs attributes William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 13/14] counter: 104-quad-8: Replace mutex with spinlock William Breathitt Gray
` (3 subsequent siblings)
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
The events_queue_size sysfs attribute provides a way for users to
dynamically configure the Counter events queue size for the Counter
character device interface. The size is in number of struct
counter_event data structures. The number of elements will be rounded-up
to a power of 2 due to a requirement of the kfifo_alloc function called
during reallocation of the queue.
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Documentation/ABI/testing/sysfs-bus-counter | 8 ++++
drivers/counter/counter-sysfs.c | 45 +++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 0ce16669157e..06c2b3e27e0b 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -233,6 +233,14 @@ Description:
shorter or equal to configured value are ignored. Value 0 means
filter is disabled.
+What: /sys/bus/counter/devices/counterX/events_queue_size
+KernelVersion: 5.16
+Contact: linux-iio@vger.kernel.org
+Description:
+ Size of the Counter events queue in number of struct
+ counter_event data structures. The number of elements will be
+ rounded-up to a power of 2.
+
What: /sys/bus/counter/devices/counterX/name
KernelVersion: 5.2
Contact: linux-iio@vger.kernel.org
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 97d8d7c2a2b6..b90f404b1fa1 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -3,11 +3,13 @@
* Generic Counter sysfs interface
* Copyright (C) 2020 William Breathitt Gray
*/
+#include <linux/bitops.h>
#include <linux/counter.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
+#include <linux/kfifo.h>
#include <linux/kstrtox.h>
#include <linux/list.h>
#include <linux/string.h>
@@ -783,12 +785,49 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val)
return 0;
}
+static int counter_events_queue_size_read(struct counter_device *counter,
+ u64 *val)
+{
+ *val = kfifo_size(&counter->events);
+ return 0;
+}
+
+static int counter_events_queue_size_write(struct counter_device *counter,
+ u64 val)
+{
+ DECLARE_KFIFO_PTR(events, struct counter_event);
+ int err = 0;
+
+ /* Verify chrdev is not currently being used */
+ if (test_and_set_bit_lock(0, counter->chrdev_lock))
+ return -EBUSY;
+
+ /* Allocate new events queue */
+ err = kfifo_alloc(&events, val, GFP_KERNEL);
+ if (err)
+ goto exit_early;
+
+ /* Swap in new events queue */
+ kfifo_free(&counter->events);
+ counter->events.kfifo = events.kfifo;
+
+exit_early:
+ clear_bit_unlock(0, counter->chrdev_lock);
+
+ return err;
+}
+
static struct counter_comp counter_num_signals_comp =
COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
static struct counter_comp counter_num_counts_comp =
COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
+static struct counter_comp counter_events_queue_size_comp =
+ COUNTER_COMP_DEVICE_U64("events_queue_size",
+ counter_events_queue_size_read,
+ counter_events_queue_size_write);
+
static int counter_sysfs_attr_add(struct counter_device *const counter,
struct counter_attribute_group *cattr_group)
{
@@ -827,6 +866,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
if (err < 0)
return err;
+ /* Create events_queue_size attribute */
+ err = counter_attr_create(dev, cattr_group,
+ &counter_events_queue_size_comp, scope, NULL);
+ if (err < 0)
+ return err;
+
/* Create an attribute for each extension */
for (i = 0; i < counter->num_ext; i++) {
ext = &counter->ext[i];
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 13/14] counter: 104-quad-8: Replace mutex with spinlock
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (10 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 12/14] counter: Implement events_queue_size sysfs attribute William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 14/14] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 William Breathitt Gray
` (2 subsequent siblings)
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
This patch replaces the mutex I/O lock with a spinlock. This is in
preparation for a subsequent patch adding IRQ support for 104-QUAD-8
devices; we can't sleep in an interrupt context, so we'll need to use a
spinlock instead.
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/104-quad-8.c | 89 +++++++++++++++++++++---------------
1 file changed, 52 insertions(+), 37 deletions(-)
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index c587f295d720..a56751bf1e9b 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
+#include <linux/spinlock.h>
#define QUAD8_EXTENT 32
@@ -43,7 +44,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
* @base: base port address of the device
*/
struct quad8 {
- struct mutex lock;
+ spinlock_t lock;
struct counter_device counter;
unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
unsigned int preset[QUAD8_NUM_COUNTERS];
@@ -124,6 +125,7 @@ static int quad8_count_read(struct counter_device *counter,
unsigned int flags;
unsigned int borrow;
unsigned int carry;
+ unsigned long irqflags;
int i;
flags = inb(base_offset + 1);
@@ -133,7 +135,7 @@ static int quad8_count_read(struct counter_device *counter,
/* Borrow XOR Carry effectively doubles count range */
*val = (unsigned long)(borrow ^ carry) << 24;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
/* Reset Byte Pointer; transfer Counter to Output Latch */
outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
@@ -142,7 +144,7 @@ static int quad8_count_read(struct counter_device *counter,
for (i = 0; i < 3; i++)
*val |= (unsigned long)inb(base_offset) << (8 * i);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -152,13 +154,14 @@ static int quad8_count_write(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const int base_offset = priv->base + 2 * count->id;
+ unsigned long irqflags;
int i;
/* Only 24-bit values are supported */
if (val > 0xFFFFFF)
return -ERANGE;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
/* Reset Byte Pointer */
outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
@@ -183,7 +186,7 @@ static int quad8_count_write(struct counter_device *counter,
/* Reset Error flag */
outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -201,8 +204,9 @@ static int quad8_function_read(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const int id = count->id;
+ unsigned long irqflags;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
if (priv->quadrature_mode[id])
switch (priv->quadrature_scale[id]) {
@@ -219,7 +223,7 @@ static int quad8_function_read(struct counter_device *counter,
else
*function = COUNTER_FUNCTION_PULSE_DIRECTION;
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -234,10 +238,11 @@ static int quad8_function_write(struct counter_device *counter,
unsigned int *const scale = priv->quadrature_scale + id;
unsigned int *const synchronous_mode = priv->synchronous_mode + id;
const int base_offset = priv->base + 2 * id + 1;
+ unsigned long irqflags;
unsigned int mode_cfg;
unsigned int idr_cfg;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
mode_cfg = priv->count_mode[id] << 1;
idr_cfg = priv->index_polarity[id] << 1;
@@ -272,7 +277,7 @@ static int quad8_function_write(struct counter_device *counter,
break;
default:
/* should never reach this path */
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return -EINVAL;
}
}
@@ -280,7 +285,7 @@ static int quad8_function_write(struct counter_device *counter,
/* Load mode configuration to Counter Mode Register */
outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -406,9 +411,10 @@ static int quad8_index_polarity_set(struct counter_device *counter,
struct quad8 *const priv = counter->priv;
const size_t channel_id = signal->id - 16;
const int base_offset = priv->base + 2 * channel_id + 1;
+ unsigned long irqflags;
unsigned int idr_cfg = index_polarity << 1;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
idr_cfg |= priv->synchronous_mode[channel_id];
@@ -417,7 +423,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
/* Load Index Control configuration to Index Control Register */
outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -446,15 +452,16 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
struct quad8 *const priv = counter->priv;
const size_t channel_id = signal->id - 16;
const int base_offset = priv->base + 2 * channel_id + 1;
+ unsigned long irqflags;
unsigned int idr_cfg = synchronous_mode;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
idr_cfg |= priv->index_polarity[channel_id] << 1;
/* Index function must be non-synchronous in non-quadrature mode */
if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return -EINVAL;
}
@@ -463,7 +470,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
/* Load Index Control configuration to Index Control Register */
outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -510,6 +517,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
unsigned int count_mode;
unsigned int mode_cfg;
const int base_offset = priv->base + 2 * count->id + 1;
+ unsigned long irqflags;
/* Map Generic Counter count mode to 104-QUAD-8 count mode */
switch (cnt_mode) {
@@ -530,7 +538,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
return -EINVAL;
}
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
priv->count_mode[count->id] = count_mode;
@@ -544,7 +552,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
/* Load mode configuration to Counter Mode Register */
outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -564,9 +572,10 @@ static int quad8_count_enable_write(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const int base_offset = priv->base + 2 * count->id;
+ unsigned long irqflags;
unsigned int ior_cfg;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
priv->ab_enable[count->id] = enable;
@@ -575,7 +584,7 @@ static int quad8_count_enable_write(struct counter_device *counter,
/* Load I/O control configuration */
outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -626,16 +635,17 @@ static int quad8_count_preset_write(struct counter_device *counter,
struct counter_count *count, u64 preset)
{
struct quad8 *const priv = counter->priv;
+ unsigned long irqflags;
/* Only 24-bit values are supported */
if (preset > 0xFFFFFF)
return -ERANGE;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
quad8_preset_register_set(priv, count->id, preset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -644,8 +654,9 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
struct counter_count *count, u64 *ceiling)
{
struct quad8 *const priv = counter->priv;
+ unsigned long irqflags;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
/* Range Limit and Modulo-N count modes use preset value as ceiling */
switch (priv->count_mode[count->id]) {
@@ -659,7 +670,7 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
break;
}
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -668,23 +679,24 @@ static int quad8_count_ceiling_write(struct counter_device *counter,
struct counter_count *count, u64 ceiling)
{
struct quad8 *const priv = counter->priv;
+ unsigned long irqflags;
/* Only 24-bit values are supported */
if (ceiling > 0xFFFFFF)
return -ERANGE;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
/* Range Limit and Modulo-N count modes use preset value as ceiling */
switch (priv->count_mode[count->id]) {
case 1:
case 3:
quad8_preset_register_set(priv, count->id, ceiling);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return -EINVAL;
}
@@ -706,12 +718,13 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const int base_offset = priv->base + 2 * count->id + 1;
+ unsigned long irqflags;
unsigned int ior_cfg;
/* Preset enable is active low in Input/Output Control register */
preset_enable = !preset_enable;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
priv->preset_enable[count->id] = preset_enable;
@@ -720,7 +733,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
/* Load I/O control configuration to Input / Output Control Register */
outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -731,22 +744,23 @@ static int quad8_signal_cable_fault_read(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const size_t channel_id = signal->id / 2;
+ unsigned long irqflags;
bool disabled;
unsigned int status;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
disabled = !(priv->cable_fault_enable & BIT(channel_id));
if (disabled) {
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return -EINVAL;
}
/* Logic 0 = cable fault */
status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
/* Mask respective channel and invert logic */
*cable_fault = !(status & BIT(channel_id));
@@ -772,9 +786,10 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
{
struct quad8 *const priv = counter->priv;
const size_t channel_id = signal->id / 2;
+ unsigned long irqflags;
unsigned int cable_fault_enable;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
if (enable)
priv->cable_fault_enable |= BIT(channel_id);
@@ -786,7 +801,7 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -809,8 +824,9 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
struct quad8 *const priv = counter->priv;
const size_t channel_id = signal->id / 2;
const int base_offset = priv->base + 2 * channel_id;
+ unsigned long irqflags;
- mutex_lock(&priv->lock);
+ spin_lock_irqsave(&priv->lock, irqflags);
priv->fck_prescaler[channel_id] = prescaler;
@@ -822,7 +838,7 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
base_offset + 1);
- mutex_unlock(&priv->lock);
+ spin_unlock_irqrestore(&priv->lock, irqflags);
return 0;
}
@@ -991,8 +1007,7 @@ static int quad8_probe(struct device *dev, unsigned int id)
priv->counter.priv = priv;
priv->base = base[id];
- /* Initialize mutex */
- mutex_init(&priv->lock);
+ spin_lock_init(&priv->lock);
/* Reset all counters and disable interrupt function */
outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v16 14/14] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (11 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 13/14] counter: 104-quad-8: Replace mutex with spinlock William Breathitt Gray
@ 2021-08-27 3:47 ` William Breathitt Gray
2021-08-30 17:17 ` [PATCH v16 00/14] Introduce the Counter character device interface Jonathan Cameron
[not found] ` <c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com>
14 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-27 3:47 UTC (permalink / raw)
To: jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
William Breathitt Gray
The LSI/CSI LS7266R1 chip provides programmable output via the FLG pins.
When interrupts are enabled on the ACCES 104-QUAD-8, they occur whenever
FLG1 is active. Four functions are available for the FLG1 signal: Carry,
Compare, Carry-Borrow, and Index.
Carry:
Interrupt generated on active low Carry signal. Carry
signal toggles every time the respective channel's
counter overflows.
Compare:
Interrupt generated on active low Compare signal.
Compare signal toggles every time respective channel's
preset register is equal to the respective channel's
counter.
Carry-Borrow:
Interrupt generated on active low Carry signal and
active low Borrow signal. Carry signal toggles every
time the respective channel's counter overflows. Borrow
signal toggles every time the respective channel's
counter underflows.
Index:
Interrupt generated on active high Index signal.
These four functions correspond respectivefly to the following four
Counter event types: COUNTER_EVENT_OVERFLOW, COUNTER_EVENT_THRESHOLD,
COUNTER_EVENT_OVERFLOW_UNDERFLOW, and COUNTER_EVENT_INDEX. Interrupts
push Counter events to event channel X, where 'X' is the respective
channel whose FLG1 activated.
This patch adds IRQ support for the ACCES 104-QUAD-8. The interrupt line
numbers for the devices may be configured via the irq array module
parameter.
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
drivers/counter/104-quad-8.c | 167 +++++++++++++++++++++++++++++++++--
drivers/counter/Kconfig | 6 +-
2 files changed, 164 insertions(+), 9 deletions(-)
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index a56751bf1e9b..1cbd60aaed69 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -11,6 +11,7 @@
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/ioport.h>
+#include <linux/interrupt.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -25,6 +26,10 @@ static unsigned int num_quad8;
module_param_hw_array(base, uint, ioport, &num_quad8, 0);
MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
+static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
+module_param_hw_array(irq, uint, irq, NULL, 0);
+MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
+
#define QUAD8_NUM_COUNTERS 8
/**
@@ -38,6 +43,8 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
* @quadrature_scale: array of quadrature mode scale configurations
* @ab_enable: array of A and B inputs enable configurations
* @preset_enable: array of set_to_preset_on_index attribute configurations
+ * @irq_trigger: array of current IRQ trigger function configurations
+ * @next_irq_trigger: array of next IRQ trigger function configurations
* @synchronous_mode: array of index function synchronous mode configurations
* @index_polarity: array of index function polarity configurations
* @cable_fault_enable: differential encoder cable status enable configurations
@@ -53,13 +60,17 @@ struct quad8 {
unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
unsigned int ab_enable[QUAD8_NUM_COUNTERS];
unsigned int preset_enable[QUAD8_NUM_COUNTERS];
+ unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
+ unsigned int next_irq_trigger[QUAD8_NUM_COUNTERS];
unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
unsigned int index_polarity[QUAD8_NUM_COUNTERS];
unsigned int cable_fault_enable;
unsigned int base;
};
+#define QUAD8_REG_INTERRUPT_STATUS 0x10
#define QUAD8_REG_CHAN_OP 0x11
+#define QUAD8_REG_INDEX_INTERRUPT 0x12
#define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
#define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
/* Borrow Toggle flip-flop */
@@ -92,8 +103,8 @@ struct quad8 {
#define QUAD8_RLD_CNTR_OUT 0x10
/* Transfer Preset Register LSB to FCK Prescaler */
#define QUAD8_RLD_PRESET_PSC 0x18
-#define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00
#define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
+#define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
#define QUAD8_CMR_QUADRATURE_X1 0x08
#define QUAD8_CMR_QUADRATURE_X2 0x10
#define QUAD8_CMR_QUADRATURE_X4 0x18
@@ -378,13 +389,103 @@ static int quad8_action_read(struct counter_device *counter,
}
}
+enum {
+ QUAD8_EVENT_NONE = -1,
+ QUAD8_EVENT_CARRY = 0,
+ QUAD8_EVENT_COMPARE = 1,
+ QUAD8_EVENT_CARRY_BORROW = 2,
+ QUAD8_EVENT_INDEX = 3,
+};
+
+static int quad8_events_configure(struct counter_device *counter)
+{
+ struct quad8 *const priv = counter->priv;
+ unsigned long irq_enabled = 0;
+ unsigned long irqflags;
+ size_t channel;
+ unsigned long ior_cfg;
+ unsigned long base_offset;
+
+ spin_lock_irqsave(&priv->lock, irqflags);
+
+ /* Enable interrupts for the requested channels, disable for the rest */
+ for (channel = 0; channel < QUAD8_NUM_COUNTERS; channel++) {
+ if (priv->next_irq_trigger[channel] == QUAD8_EVENT_NONE)
+ continue;
+
+ if (priv->irq_trigger[channel] != priv->next_irq_trigger[channel]) {
+ /* Save new IRQ function configuration */
+ priv->irq_trigger[channel] = priv->next_irq_trigger[channel];
+
+ /* Load configuration to I/O Control Register */
+ ior_cfg = priv->ab_enable[channel] |
+ priv->preset_enable[channel] << 1 |
+ priv->irq_trigger[channel] << 3;
+ base_offset = priv->base + 2 * channel + 1;
+ outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
+ }
+
+ /* Reset next IRQ trigger function configuration */
+ priv->next_irq_trigger[channel] = QUAD8_EVENT_NONE;
+
+ /* Enable IRQ line */
+ irq_enabled |= BIT(channel);
+ }
+
+ outb(irq_enabled, priv->base + QUAD8_REG_INDEX_INTERRUPT);
+
+ spin_unlock_irqrestore(&priv->lock, irqflags);
+
+ return 0;
+}
+
+static int quad8_watch_validate(struct counter_device *counter,
+ const struct counter_watch *watch)
+{
+ struct quad8 *const priv = counter->priv;
+
+ if (watch->channel > QUAD8_NUM_COUNTERS - 1)
+ return -EINVAL;
+
+ switch (watch->event) {
+ case COUNTER_EVENT_OVERFLOW:
+ if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+ priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY;
+ else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY)
+ return -EINVAL;
+ return 0;
+ case COUNTER_EVENT_THRESHOLD:
+ if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+ priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_COMPARE;
+ else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_COMPARE)
+ return -EINVAL;
+ return 0;
+ case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
+ if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+ priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY_BORROW;
+ else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY_BORROW)
+ return -EINVAL;
+ return 0;
+ case COUNTER_EVENT_INDEX:
+ if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+ priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_INDEX;
+ else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_INDEX)
+ return -EINVAL;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
static const struct counter_ops quad8_ops = {
.signal_read = quad8_signal_read,
.count_read = quad8_count_read,
.count_write = quad8_count_write,
.function_read = quad8_function_read,
.function_write = quad8_function_write,
- .action_read = quad8_action_read
+ .action_read = quad8_action_read,
+ .events_configure = quad8_events_configure,
+ .watch_validate = quad8_watch_validate,
};
static const char *const quad8_index_polarity_modes[] = {
@@ -579,7 +680,8 @@ static int quad8_count_enable_write(struct counter_device *counter,
priv->ab_enable[count->id] = enable;
- ior_cfg = enable | priv->preset_enable[count->id] << 1;
+ ior_cfg = enable | priv->preset_enable[count->id] << 1 |
+ priv->irq_trigger[count->id] << 3;
/* Load I/O control configuration */
outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
@@ -728,7 +830,8 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
priv->preset_enable[count->id] = preset_enable;
- ior_cfg = priv->ab_enable[count->id] | preset_enable << 1;
+ ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
+ priv->irq_trigger[count->id] << 3;
/* Load I/O control configuration to Input / Output Control Register */
outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
@@ -980,11 +1083,54 @@ static struct counter_count quad8_counts[] = {
QUAD8_COUNT(7, "Channel 8 Count")
};
+static irqreturn_t quad8_irq_handler(int irq, void *private)
+{
+ struct quad8 *const priv = private;
+ const unsigned long base = priv->base;
+ unsigned long irq_status;
+ unsigned long channel;
+ u8 event;
+
+ irq_status = inb(base + QUAD8_REG_INTERRUPT_STATUS);
+ if (!irq_status)
+ return IRQ_NONE;
+
+ for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
+ switch (priv->irq_trigger[channel]) {
+ case QUAD8_EVENT_CARRY:
+ event = COUNTER_EVENT_OVERFLOW;
+ break;
+ case QUAD8_EVENT_COMPARE:
+ event = COUNTER_EVENT_THRESHOLD;
+ break;
+ case QUAD8_EVENT_CARRY_BORROW:
+ event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
+ break;
+ case QUAD8_EVENT_INDEX:
+ event = COUNTER_EVENT_INDEX;
+ break;
+ default:
+ /* should never reach this path */
+ WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
+ priv->irq_trigger[channel], channel);
+ continue;
+ }
+
+ counter_push_event(&priv->counter, event, channel);
+ }
+
+ /* Clear pending interrupts on device */
+ outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base + QUAD8_REG_CHAN_OP);
+
+ return IRQ_HANDLED;
+}
+
static int quad8_probe(struct device *dev, unsigned int id)
{
struct quad8 *priv;
int i, j;
unsigned int base_offset;
+ int err;
if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
@@ -1009,6 +1155,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
spin_lock_init(&priv->lock);
+ /* Reset Index/Interrupt Register */
+ outb(0x00, base[id] + QUAD8_REG_INDEX_INTERRUPT);
/* Reset all counters and disable interrupt function */
outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
/* Set initial configuration for all counters */
@@ -1035,11 +1183,18 @@ static int quad8_probe(struct device *dev, unsigned int id)
outb(QUAD8_CTR_IOR, base_offset + 1);
/* Disable index function; negative index polarity */
outb(QUAD8_CTR_IDR, base_offset + 1);
+ /* Initialize next IRQ trigger function configuration */
+ priv->next_irq_trigger[i] = QUAD8_EVENT_NONE;
}
/* Disable Differential Encoder Cable Status for all channels */
outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
- /* Enable all counters */
- outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
+ /* Enable all counters and enable interrupt function */
+ outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
+
+ err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
+ priv->counter.name, priv);
+ if (err)
+ return err;
return devm_counter_register(dev, &priv->counter);
}
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index d5d2540b30c2..3dcdb681c4e4 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -23,11 +23,11 @@ config 104_QUAD_8
A counter's respective error flag may be cleared by performing a write
operation on the respective count value attribute. Although the
104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
- set, either directly or via the counter's preset attribute. Interrupts
- are not supported by this driver.
+ set, either directly or via the counter's preset attribute.
The base port addresses for the devices may be configured via the base
- array module parameter.
+ array module parameter. The interrupt line numbers for the devices may
+ be configured via the irq array module parameter.
config INTERRUPT_CNT
tristate "Interrupt counter driver"
--
2.32.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* Re: [PATCH v16 00/14] Introduce the Counter character device interface
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
` (12 preceding siblings ...)
2021-08-27 3:47 ` [PATCH v16 14/14] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 William Breathitt Gray
@ 2021-08-30 17:17 ` Jonathan Cameron
2021-09-12 16:36 ` Jonathan Cameron
[not found] ` <c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com>
14 siblings, 1 reply; 32+ messages in thread
From: Jonathan Cameron @ 2021-08-30 17:17 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On Fri, 27 Aug 2021 12:47:44 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> Changes in v16:
> - Define magic numbers for stm32-lptimer-cnt clock polarities
> - Define magic numbers for stm32-timer-cnt encoder modes
> - Bump KernelVersion to 5.16 in sysfs-bus-counter ABI documentation
> - Fix typos in driver API generic-counter.rst documentation file
>
> For convenience, this patchset is also available on my personal git
> repo: https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v16
>
> The patches preceding "counter: Internalize sysfs interface code" are
> primarily cleanup and fixes that can be picked up and applied now to the
> IIO tree if so desired. The "counter: Internalize sysfs interface code"
> patch as well may be considered for pickup because it is relatively safe
> and makes no changes to the userspace interface.
>
> To summarize the main points of this patchset: there are no changes to
> the existing Counter sysfs userspace interface; a Counter character
> device interface is introduced that allows Counter events and associated
> data to be read() by userspace; the events_configure() and
> watch_validate() driver callbacks are introduced to support Counter
> events; and IRQ support is added to the 104-QUAD-8 driver, serving as an
> example of how to support the new Counter events functionality.
Hi William,
I'll aim to pick up the first part in a week (too tired today after a lot
of reviewing to even manage the basic sanity check on the changes).
For the rest...
What I'd really like to know is if anyone other than William and I is planning
to review them in depth? (particularly 7 and 8 which are the new interface
patch and docs)
So if anyone reading this is in that category please let me know. We can wait,
but conversely if no one is going to get time / inclination to do it then I
don't want to hold these up any longer and maximum time in linux-next may
be more useful than sitting unloved on the mailing list.
Jonathan
>
> William Breathitt Gray (14):
> counter: stm32-lptimer-cnt: Provide defines for clock polarities
> counter: stm32-timer-cnt: Provide defines for slave mode selection
> counter: Internalize sysfs interface code
> counter: Update counter.h comments to reflect sysfs internalization
> docs: counter: Update to reflect sysfs internalization
> counter: Move counter enums to uapi header
> counter: Add character device interface
> docs: counter: Document character device interface
> tools/counter: Create Counter tools
> counter: Implement signalZ_action_component_id sysfs attribute
> counter: Implement *_component_id sysfs attributes
> counter: Implement events_queue_size sysfs attribute
> counter: 104-quad-8: Replace mutex with spinlock
> counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
>
> Documentation/ABI/testing/sysfs-bus-counter | 38 +-
> Documentation/driver-api/generic-counter.rst | 358 +++-
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> MAINTAINERS | 3 +-
> drivers/counter/104-quad-8.c | 699 ++++----
> drivers/counter/Kconfig | 6 +-
> drivers/counter/Makefile | 1 +
> drivers/counter/counter-chrdev.c | 553 ++++++
> drivers/counter/counter-chrdev.h | 14 +
> drivers/counter/counter-core.c | 191 +++
> drivers/counter/counter-sysfs.c | 960 +++++++++++
> drivers/counter/counter-sysfs.h | 13 +
> drivers/counter/counter.c | 1496 -----------------
> drivers/counter/ftm-quaddec.c | 60 +-
> drivers/counter/intel-qep.c | 144 +-
> drivers/counter/interrupt-cnt.c | 62 +-
> drivers/counter/microchip-tcb-capture.c | 91 +-
> drivers/counter/stm32-lptimer-cnt.c | 212 ++-
> drivers/counter/stm32-timer-cnt.c | 195 +--
> drivers/counter/ti-eqep.c | 180 +-
> include/linux/counter.h | 715 ++++----
> include/linux/counter_enum.h | 45 -
> include/linux/mfd/stm32-lptimer.h | 5 +
> include/linux/mfd/stm32-timers.h | 4 +
> include/uapi/linux/counter.h | 154 ++
> tools/Makefile | 13 +-
> tools/counter/Build | 1 +
> tools/counter/Makefile | 53 +
> tools/counter/counter_example.c | 93 +
> 29 files changed, 3569 insertions(+), 2791 deletions(-)
> create mode 100644 drivers/counter/counter-chrdev.c
> create mode 100644 drivers/counter/counter-chrdev.h
> create mode 100644 drivers/counter/counter-core.c
> create mode 100644 drivers/counter/counter-sysfs.c
> create mode 100644 drivers/counter/counter-sysfs.h
> delete mode 100644 drivers/counter/counter.c
> delete mode 100644 include/linux/counter_enum.h
> create mode 100644 include/uapi/linux/counter.h
> create mode 100644 tools/counter/Build
> create mode 100644 tools/counter/Makefile
> create mode 100644 tools/counter/counter_example.c
>
>
> base-commit: 5ffeb17c0d3dd44704b4aee83e297ec07666e4d6
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities
2021-08-27 3:47 ` [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities William Breathitt Gray
@ 2021-08-31 13:38 ` Fabrice Gasnier
2021-09-08 17:31 ` Jonathan Cameron
0 siblings, 1 reply; 32+ messages in thread
From: Fabrice Gasnier @ 2021-08-31 13:38 UTC (permalink / raw)
To: William Breathitt Gray, jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> The STM32 low-power timer permits configuration of the clock polarity
> via the LPTIMX_CFGR register CKPOL bits. This patch provides
> preprocessor defines for the supported clock polarities.
>
> Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
> drivers/counter/stm32-lptimer-cnt.c | 6 +++---
> include/linux/mfd/stm32-lptimer.h | 5 +++++
> 2 files changed, 8 insertions(+), 3 deletions(-)
Hi William,
You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Thanks,
Fabrice
>
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index 13656957c45f..7367f46c6f91 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -140,9 +140,9 @@ static const enum counter_function stm32_lptim_cnt_functions[] = {
> };
>
> enum stm32_lptim_synapse_action {
> - STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
> - STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
> - STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
> + STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE = STM32_LPTIM_CKPOL_RISING_EDGE,
> + STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE = STM32_LPTIM_CKPOL_FALLING_EDGE,
> + STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES = STM32_LPTIM_CKPOL_BOTH_EDGES,
> STM32_LPTIM_SYNAPSE_ACTION_NONE,
> };
>
> diff --git a/include/linux/mfd/stm32-lptimer.h b/include/linux/mfd/stm32-lptimer.h
> index 90b20550c1c8..06d3f11dc3c9 100644
> --- a/include/linux/mfd/stm32-lptimer.h
> +++ b/include/linux/mfd/stm32-lptimer.h
> @@ -45,6 +45,11 @@
> #define STM32_LPTIM_PRESC GENMASK(11, 9)
> #define STM32_LPTIM_CKPOL GENMASK(2, 1)
>
> +/* STM32_LPTIM_CKPOL */
> +#define STM32_LPTIM_CKPOL_RISING_EDGE 0
> +#define STM32_LPTIM_CKPOL_FALLING_EDGE 1
> +#define STM32_LPTIM_CKPOL_BOTH_EDGES 2
> +
> /* STM32_LPTIM_ARR */
> #define STM32_LPTIM_MAX_ARR 0xFFFF
>
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection
2021-08-27 3:47 ` [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection William Breathitt Gray
@ 2021-08-31 13:40 ` Fabrice Gasnier
2021-09-08 17:31 ` Jonathan Cameron
0 siblings, 1 reply; 32+ messages in thread
From: Fabrice Gasnier @ 2021-08-31 13:40 UTC (permalink / raw)
To: William Breathitt Gray, jic23
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> The STM32 timer permits configuration of the counter encoder mode via
> the slave mode control register (SMCR) slave mode selection (SMS) bits.
> This patch provides preprocessor defines for the supported encoder
> modes.
>
> Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
> drivers/counter/stm32-timer-cnt.c | 16 ++++++++--------
> include/linux/mfd/stm32-timers.h | 4 ++++
> 2 files changed, 12 insertions(+), 8 deletions(-)
Hi William,
You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Thanks,
Fabrice
>
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index 3fb0debd7425..1fbc46f4ee66 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -93,16 +93,16 @@ static int stm32_count_function_get(struct counter_device *counter,
> regmap_read(priv->regmap, TIM_SMCR, &smcr);
>
> switch (smcr & TIM_SMCR_SMS) {
> - case 0:
> + case TIM_SMCR_SMS_SLAVE_MODE_DISABLED:
> *function = STM32_COUNT_SLAVE_MODE_DISABLED;
> return 0;
> - case 1:
> + case TIM_SMCR_SMS_ENCODER_MODE_1:
> *function = STM32_COUNT_ENCODER_MODE_1;
> return 0;
> - case 2:
> + case TIM_SMCR_SMS_ENCODER_MODE_2:
> *function = STM32_COUNT_ENCODER_MODE_2;
> return 0;
> - case 3:
> + case TIM_SMCR_SMS_ENCODER_MODE_3:
> *function = STM32_COUNT_ENCODER_MODE_3;
> return 0;
> default:
> @@ -119,16 +119,16 @@ static int stm32_count_function_set(struct counter_device *counter,
>
> switch (function) {
> case STM32_COUNT_SLAVE_MODE_DISABLED:
> - sms = 0;
> + sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
> break;
> case STM32_COUNT_ENCODER_MODE_1:
> - sms = 1;
> + sms = TIM_SMCR_SMS_ENCODER_MODE_1;
> break;
> case STM32_COUNT_ENCODER_MODE_2:
> - sms = 2;
> + sms = TIM_SMCR_SMS_ENCODER_MODE_2;
> break;
> case STM32_COUNT_ENCODER_MODE_3:
> - sms = 3;
> + sms = TIM_SMCR_SMS_ENCODER_MODE_3;
> break;
> default:
> return -EINVAL;
> diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
> index f8db83aedb2b..5f5c43fd69dd 100644
> --- a/include/linux/mfd/stm32-timers.h
> +++ b/include/linux/mfd/stm32-timers.h
> @@ -82,6 +82,10 @@
> #define MAX_TIM_ICPSC 0x3
> #define TIM_CR2_MMS_SHIFT 4
> #define TIM_CR2_MMS2_SHIFT 20
> +#define TIM_SMCR_SMS_SLAVE_MODE_DISABLED 0 /* counts on internal clock when CEN=1 */
> +#define TIM_SMCR_SMS_ENCODER_MODE_1 1 /* counts TI1FP1 edges, depending on TI2FP2 level */
> +#define TIM_SMCR_SMS_ENCODER_MODE_2 2 /* counts TI2FP2 edges, depending on TI1FP1 level */
> +#define TIM_SMCR_SMS_ENCODER_MODE_3 3 /* counts on both TI1FP1 and TI2FP2 edges */
> #define TIM_SMCR_TS_SHIFT 4
> #define TIM_BDTR_BKF_MASK 0xF
> #define TIM_BDTR_BKF_SHIFT(x) (16 + (x) * 4)
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs interface code
[not found] ` <fcff44a7-5ac2-a510-ee9b-85ef7e2e29ef@foss.st.com>
@ 2021-08-31 14:16 ` William Breathitt Gray
2021-08-31 14:55 ` William Breathitt Gray
0 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-31 14:16 UTC (permalink / raw)
To: Fabrice Gasnier
Cc: jic23, kamel.bouhara, gwendal, david, linux-iio,
patrick.havelange, alexandre.belloni, mcoquelin.stm32,
linux-kernel, o.rempel, jarkko.nikula, Dan Carpenter, kernel,
fabrice.gasnier, syednwaris, linux-stm32, linux-arm-kernel,
alexandre.torgue
[-- Attachment #1: Type: text/plain, Size: 8813 bytes --]
On Tue, Aug 31, 2021 at 03:44:04PM +0200, Fabrice Gasnier wrote:
> On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> > This is a reimplementation of the Generic Counter driver interface.
> > There are no modifications to the Counter subsystem userspace interface,
> > so existing userspace applications should continue to run seamlessly.
> >
> > The purpose of this patch is to internalize the sysfs interface code
> > among the various counter drivers into a shared module. Counter drivers
> > pass and take data natively (i.e. u8, u64, etc.) and the shared counter
> > module handles the translation between the sysfs interface and the
> > device drivers. This guarantees a standard userspace interface for all
> > counter drivers, and helps generalize the Generic Counter driver ABI in
> > order to support the Generic Counter chrdev interface (introduced in a
> > subsequent patch) without significant changes to the existing counter
> > drivers.
> >
> > Note, Counter device registration is the same as before: drivers
> > populate a struct counter_device with components and callbacks, then
> > pass the structure to the devm_counter_register function. However,
> > what's different now is how the Counter subsystem code handles this
> > registration internally.
> >
> > Whereas before callbacks would interact directly with sysfs data, this
> > interaction is now abstracted and instead callbacks interact with native
> > C data types. The counter_comp structure forms the basis for Counter
> > extensions.
> >
> > The counter-sysfs.c file contains the code to parse through the
> > counter_device structure and register the requested components and
> > extensions. Attributes are created and populated based on type, with
> > respective translation functions to handle the mapping between sysfs and
> > the counter driver callbacks.
> >
> > The translation performed for each attribute is straightforward: the
> > attribute type and data is parsed from the counter_attribute structure,
> > the respective counter driver read/write callback is called, and sysfs
> > I/O is handled before or after the driver read/write function is called.
> >
> > Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> > Cc: Patrick Havelange <patrick.havelange@essensium.com>
> > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> > Cc: Alexandre Torgue <alexandre.torgue@st.com>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> > Reviewed-by: David Lechner <david@lechnology.com>
> > Tested-by: David Lechner <david@lechnology.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> > MAINTAINERS | 1 -
> > drivers/counter/104-quad-8.c | 449 +++----
> > drivers/counter/Makefile | 1 +
> > drivers/counter/counter-core.c | 142 +++
> > drivers/counter/counter-sysfs.c | 849 +++++++++++++
> > drivers/counter/counter-sysfs.h | 13 +
> > drivers/counter/counter.c | 1496 -----------------------
> > drivers/counter/ftm-quaddec.c | 60 +-
> > drivers/counter/intel-qep.c | 144 +--
> > drivers/counter/interrupt-cnt.c | 62 +-
> > drivers/counter/microchip-tcb-capture.c | 91 +-
> > drivers/counter/stm32-lptimer-cnt.c | 212 ++--
> > drivers/counter/stm32-timer-cnt.c | 179 ++-
> > drivers/counter/ti-eqep.c | 180 +--
> > include/linux/counter.h | 658 +++++-----
> > include/linux/counter_enum.h | 45 -
> > 16 files changed, 1949 insertions(+), 2633 deletions(-)
> > create mode 100644 drivers/counter/counter-core.c
> > create mode 100644 drivers/counter/counter-sysfs.c
> > create mode 100644 drivers/counter/counter-sysfs.h
> > delete mode 100644 drivers/counter/counter.c
> > delete mode 100644 include/linux/counter_enum.h
> >
>
> Hi William,
>
> For the STM32 drivers, you can add my:
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
>
> Thanks,
> Fabrice
Hello Fabrice,
I noticed the stm32-lptimer-cnt.c function_write() and action_write()
callbacks do not appear to write the desired function/action
configuration to the device. Would you check whether the device actually
supports this functionality or if these callbacks should be removed from
this driver.
Thanks,
William Breathitt Gray
> > diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> > index 7367f46c6f91..5168833b1fdf 100644
> > --- a/drivers/counter/stm32-lptimer-cnt.c
> > +++ b/drivers/counter/stm32-lptimer-cnt.c
> > @@ -170,28 +154,28 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
> > return 0;
> > }
> >
> > -static int stm32_lptim_cnt_function_get(struct counter_device *counter,
> > - struct counter_count *count,
> > - size_t *function)
> > +static int stm32_lptim_cnt_function_read(struct counter_device *counter,
> > + struct counter_count *count,
> > + enum counter_function *function)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> >
> > if (!priv->quadrature_mode) {
> > - *function = STM32_LPTIM_COUNTER_INCREASE;
> > + *function = COUNTER_FUNCTION_INCREASE;
> > return 0;
> > }
> >
> > - if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {
> > - *function = STM32_LPTIM_ENCODER_BOTH_EDGE;
> > + if (priv->polarity == STM32_LPTIM_CKPOL_BOTH_EDGES) {
> > + *function = COUNTER_FUNCTION_QUADRATURE_X4;
> > return 0;
> > }
> >
> > return -EINVAL;
> > }
> >
> > -static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> > - struct counter_count *count,
> > - size_t function)
> > +static int stm32_lptim_cnt_function_write(struct counter_device *counter,
> > + struct counter_count *count,
> > + enum counter_function function)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> >
> > @@ -199,12 +183,12 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> > return -EBUSY;
> >
> > switch (function) {
> > - case STM32_LPTIM_COUNTER_INCREASE:
> > + case COUNTER_FUNCTION_INCREASE:
> > priv->quadrature_mode = 0;
> > return 0;
> > - case STM32_LPTIM_ENCODER_BOTH_EDGE:
> > + case COUNTER_FUNCTION_QUADRATURE_X4:
> > priv->quadrature_mode = 1;
> > - priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
> > + priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> > return 0;
> > default:
> > /* should never reach this path */
> > @@ -333,43 +316,48 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
> > }
> > }
> >
> > -static int stm32_lptim_cnt_action_set(struct counter_device *counter,
> > - struct counter_count *count,
> > - struct counter_synapse *synapse,
> > - size_t action)
> > +static int stm32_lptim_cnt_action_write(struct counter_device *counter,
> > + struct counter_count *count,
> > + struct counter_synapse *synapse,
> > + enum counter_synapse_action action)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> > - size_t function;
> > + enum counter_function function;
> > int err;
> >
> > if (stm32_lptim_is_enabled(priv))
> > return -EBUSY;
> >
> > - err = stm32_lptim_cnt_function_get(counter, count, &function);
> > + err = stm32_lptim_cnt_function_read(counter, count, &function);
> > if (err)
> > return err;
> >
> > /* only set polarity when in counter mode (on input 1) */
> > - if (function == STM32_LPTIM_COUNTER_INCREASE
> > - && synapse->signal->id == count->synapses[0].signal->id) {
> > - switch (action) {
> > - case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
> > - case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
> > - case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
> > - priv->polarity = action;
> > - return 0;
> > - }
> > - }
> > + if (function != COUNTER_FUNCTION_INCREASE
> > + || synapse->signal->id != count->synapses[0].signal->id)
> > + return -EINVAL;
> >
> > - return -EINVAL;
> > + switch (action) {
> > + case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
> > + priv->polarity = STM32_LPTIM_CKPOL_RISING_EDGE;
> > + return 0;
> > + case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
> > + priv->polarity = STM32_LPTIM_CKPOL_FALLING_EDGE;
> > + return 0;
> > + case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
> > + priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> > + return 0;
> > + default:
> > + return -EINVAL;
> > + }
> > }
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs interface code
2021-08-31 14:16 ` [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs interface code William Breathitt Gray
@ 2021-08-31 14:55 ` William Breathitt Gray
0 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-08-31 14:55 UTC (permalink / raw)
To: Fabrice Gasnier
Cc: jic23, kamel.bouhara, gwendal, david, linux-iio,
patrick.havelange, alexandre.belloni, mcoquelin.stm32,
linux-kernel, o.rempel, jarkko.nikula, Dan Carpenter, kernel,
fabrice.gasnier, syednwaris, linux-stm32, linux-arm-kernel,
alexandre.torgue
[-- Attachment #1: Type: text/plain, Size: 5060 bytes --]
On Tue, Aug 31, 2021 at 11:16:59PM +0900, William Breathitt Gray wrote:
> On Tue, Aug 31, 2021 at 03:44:04PM +0200, Fabrice Gasnier wrote:
> > On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> > > This is a reimplementation of the Generic Counter driver interface.
> > > There are no modifications to the Counter subsystem userspace interface,
> > > so existing userspace applications should continue to run seamlessly.
> > >
> > > The purpose of this patch is to internalize the sysfs interface code
> > > among the various counter drivers into a shared module. Counter drivers
> > > pass and take data natively (i.e. u8, u64, etc.) and the shared counter
> > > module handles the translation between the sysfs interface and the
> > > device drivers. This guarantees a standard userspace interface for all
> > > counter drivers, and helps generalize the Generic Counter driver ABI in
> > > order to support the Generic Counter chrdev interface (introduced in a
> > > subsequent patch) without significant changes to the existing counter
> > > drivers.
> > >
> > > Note, Counter device registration is the same as before: drivers
> > > populate a struct counter_device with components and callbacks, then
> > > pass the structure to the devm_counter_register function. However,
> > > what's different now is how the Counter subsystem code handles this
> > > registration internally.
> > >
> > > Whereas before callbacks would interact directly with sysfs data, this
> > > interaction is now abstracted and instead callbacks interact with native
> > > C data types. The counter_comp structure forms the basis for Counter
> > > extensions.
> > >
> > > The counter-sysfs.c file contains the code to parse through the
> > > counter_device structure and register the requested components and
> > > extensions. Attributes are created and populated based on type, with
> > > respective translation functions to handle the mapping between sysfs and
> > > the counter driver callbacks.
> > >
> > > The translation performed for each attribute is straightforward: the
> > > attribute type and data is parsed from the counter_attribute structure,
> > > the respective counter driver read/write callback is called, and sysfs
> > > I/O is handled before or after the driver read/write function is called.
> > >
> > > Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> > > Cc: Patrick Havelange <patrick.havelange@essensium.com>
> > > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > > Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> > > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> > > Cc: Alexandre Torgue <alexandre.torgue@st.com>
> > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> > > Reviewed-by: David Lechner <david@lechnology.com>
> > > Tested-by: David Lechner <david@lechnology.com>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > ---
> > > MAINTAINERS | 1 -
> > > drivers/counter/104-quad-8.c | 449 +++----
> > > drivers/counter/Makefile | 1 +
> > > drivers/counter/counter-core.c | 142 +++
> > > drivers/counter/counter-sysfs.c | 849 +++++++++++++
> > > drivers/counter/counter-sysfs.h | 13 +
> > > drivers/counter/counter.c | 1496 -----------------------
> > > drivers/counter/ftm-quaddec.c | 60 +-
> > > drivers/counter/intel-qep.c | 144 +--
> > > drivers/counter/interrupt-cnt.c | 62 +-
> > > drivers/counter/microchip-tcb-capture.c | 91 +-
> > > drivers/counter/stm32-lptimer-cnt.c | 212 ++--
> > > drivers/counter/stm32-timer-cnt.c | 179 ++-
> > > drivers/counter/ti-eqep.c | 180 +--
> > > include/linux/counter.h | 658 +++++-----
> > > include/linux/counter_enum.h | 45 -
> > > 16 files changed, 1949 insertions(+), 2633 deletions(-)
> > > create mode 100644 drivers/counter/counter-core.c
> > > create mode 100644 drivers/counter/counter-sysfs.c
> > > create mode 100644 drivers/counter/counter-sysfs.h
> > > delete mode 100644 drivers/counter/counter.c
> > > delete mode 100644 include/linux/counter_enum.h
> > >
> >
> > Hi William,
> >
> > For the STM32 drivers, you can add my:
> > Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> >
> > Thanks,
> > Fabrice
>
> Hello Fabrice,
>
> I noticed the stm32-lptimer-cnt.c function_write() and action_write()
> callbacks do not appear to write the desired function/action
> configuration to the device. Would you check whether the device actually
> supports this functionality or if these callbacks should be removed from
> this driver.
>
> Thanks,
>
> William Breathitt Gray
Nevermind, I see that these configurations are sent to the device via
stm32_lptim_setup() when the counter is enabled. So that setup should be
fine after all.
Thanks,
William Breathitt Gray
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities
2021-08-31 13:38 ` Fabrice Gasnier
@ 2021-09-08 17:31 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-08 17:31 UTC (permalink / raw)
To: Fabrice Gasnier
Cc: William Breathitt Gray, linux-stm32, kernel, a.fatoum,
kamel.bouhara, gwendal, alexandre.belloni, david, linux-iio,
linux-kernel, linux-arm-kernel, syednwaris, patrick.havelange,
fabrice.gasnier, mcoquelin.stm32, alexandre.torgue, o.rempel,
jarkko.nikula
On Tue, 31 Aug 2021 15:38:50 +0200
Fabrice Gasnier <fabrice.gasnier@foss.st.com> wrote:
> On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> > The STM32 low-power timer permits configuration of the clock polarity
> > via the LPTIMX_CFGR register CKPOL bits. This patch provides
> > preprocessor defines for the supported clock polarities.
> >
> > Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> > drivers/counter/stm32-lptimer-cnt.c | 6 +++---
> > include/linux/mfd/stm32-lptimer.h | 5 +++++
> > 2 files changed, 8 insertions(+), 3 deletions(-)
>
> Hi William,
>
> You can add my:
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Applied to the togreg branch of iio.git and push out as testing for all the normal reasons
>
> Thanks,
> Fabrice
>
> >
> > diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> > index 13656957c45f..7367f46c6f91 100644
> > --- a/drivers/counter/stm32-lptimer-cnt.c
> > +++ b/drivers/counter/stm32-lptimer-cnt.c
> > @@ -140,9 +140,9 @@ static const enum counter_function stm32_lptim_cnt_functions[] = {
> > };
> >
> > enum stm32_lptim_synapse_action {
> > - STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
> > - STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
> > - STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
> > + STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE = STM32_LPTIM_CKPOL_RISING_EDGE,
> > + STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE = STM32_LPTIM_CKPOL_FALLING_EDGE,
> > + STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES = STM32_LPTIM_CKPOL_BOTH_EDGES,
> > STM32_LPTIM_SYNAPSE_ACTION_NONE,
> > };
> >
> > diff --git a/include/linux/mfd/stm32-lptimer.h b/include/linux/mfd/stm32-lptimer.h
> > index 90b20550c1c8..06d3f11dc3c9 100644
> > --- a/include/linux/mfd/stm32-lptimer.h
> > +++ b/include/linux/mfd/stm32-lptimer.h
> > @@ -45,6 +45,11 @@
> > #define STM32_LPTIM_PRESC GENMASK(11, 9)
> > #define STM32_LPTIM_CKPOL GENMASK(2, 1)
> >
> > +/* STM32_LPTIM_CKPOL */
> > +#define STM32_LPTIM_CKPOL_RISING_EDGE 0
> > +#define STM32_LPTIM_CKPOL_FALLING_EDGE 1
> > +#define STM32_LPTIM_CKPOL_BOTH_EDGES 2
> > +
> > /* STM32_LPTIM_ARR */
> > #define STM32_LPTIM_MAX_ARR 0xFFFF
> >
> >
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection
2021-08-31 13:40 ` Fabrice Gasnier
@ 2021-09-08 17:31 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-08 17:31 UTC (permalink / raw)
To: Fabrice Gasnier
Cc: William Breathitt Gray, linux-stm32, kernel, a.fatoum,
kamel.bouhara, gwendal, alexandre.belloni, david, linux-iio,
linux-kernel, linux-arm-kernel, syednwaris, patrick.havelange,
fabrice.gasnier, mcoquelin.stm32, alexandre.torgue, o.rempel,
jarkko.nikula
On Tue, 31 Aug 2021 15:40:37 +0200
Fabrice Gasnier <fabrice.gasnier@foss.st.com> wrote:
> On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> > The STM32 timer permits configuration of the counter encoder mode via
> > the slave mode control register (SMCR) slave mode selection (SMS) bits.
> > This patch provides preprocessor defines for the supported encoder
> > modes.
> >
> > Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> > drivers/counter/stm32-timer-cnt.c | 16 ++++++++--------
> > include/linux/mfd/stm32-timers.h | 4 ++++
> > 2 files changed, 12 insertions(+), 8 deletions(-)
>
> Hi William,
>
> You can add my:
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Applied.
Thanks,
J
>
> Thanks,
> Fabrice
>
> >
> > diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> > index 3fb0debd7425..1fbc46f4ee66 100644
> > --- a/drivers/counter/stm32-timer-cnt.c
> > +++ b/drivers/counter/stm32-timer-cnt.c
> > @@ -93,16 +93,16 @@ static int stm32_count_function_get(struct counter_device *counter,
> > regmap_read(priv->regmap, TIM_SMCR, &smcr);
> >
> > switch (smcr & TIM_SMCR_SMS) {
> > - case 0:
> > + case TIM_SMCR_SMS_SLAVE_MODE_DISABLED:
> > *function = STM32_COUNT_SLAVE_MODE_DISABLED;
> > return 0;
> > - case 1:
> > + case TIM_SMCR_SMS_ENCODER_MODE_1:
> > *function = STM32_COUNT_ENCODER_MODE_1;
> > return 0;
> > - case 2:
> > + case TIM_SMCR_SMS_ENCODER_MODE_2:
> > *function = STM32_COUNT_ENCODER_MODE_2;
> > return 0;
> > - case 3:
> > + case TIM_SMCR_SMS_ENCODER_MODE_3:
> > *function = STM32_COUNT_ENCODER_MODE_3;
> > return 0;
> > default:
> > @@ -119,16 +119,16 @@ static int stm32_count_function_set(struct counter_device *counter,
> >
> > switch (function) {
> > case STM32_COUNT_SLAVE_MODE_DISABLED:
> > - sms = 0;
> > + sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
> > break;
> > case STM32_COUNT_ENCODER_MODE_1:
> > - sms = 1;
> > + sms = TIM_SMCR_SMS_ENCODER_MODE_1;
> > break;
> > case STM32_COUNT_ENCODER_MODE_2:
> > - sms = 2;
> > + sms = TIM_SMCR_SMS_ENCODER_MODE_2;
> > break;
> > case STM32_COUNT_ENCODER_MODE_3:
> > - sms = 3;
> > + sms = TIM_SMCR_SMS_ENCODER_MODE_3;
> > break;
> > default:
> > return -EINVAL;
> > diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
> > index f8db83aedb2b..5f5c43fd69dd 100644
> > --- a/include/linux/mfd/stm32-timers.h
> > +++ b/include/linux/mfd/stm32-timers.h
> > @@ -82,6 +82,10 @@
> > #define MAX_TIM_ICPSC 0x3
> > #define TIM_CR2_MMS_SHIFT 4
> > #define TIM_CR2_MMS2_SHIFT 20
> > +#define TIM_SMCR_SMS_SLAVE_MODE_DISABLED 0 /* counts on internal clock when CEN=1 */
> > +#define TIM_SMCR_SMS_ENCODER_MODE_1 1 /* counts TI1FP1 edges, depending on TI2FP2 level */
> > +#define TIM_SMCR_SMS_ENCODER_MODE_2 2 /* counts TI2FP2 edges, depending on TI1FP1 level */
> > +#define TIM_SMCR_SMS_ENCODER_MODE_3 3 /* counts on both TI1FP1 and TI2FP2 edges */
> > #define TIM_SMCR_TS_SHIFT 4
> > #define TIM_BDTR_BKF_MASK 0xF
> > #define TIM_BDTR_BKF_SHIFT(x) (16 + (x) * 4)
> >
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization
2021-08-27 3:47 ` [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
@ 2021-09-08 17:46 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-08 17:46 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On Fri, 27 Aug 2021 12:47:48 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> The Counter subsystem architecture and driver implementations have
> changed in order to handle Counter sysfs interactions in a more
> consistent way. This patch updates the Generic Counter interface
> header file comments to reflect the changes.
>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>f
Applied
> ---
> drivers/counter/counter-core.c | 3 ++
> include/linux/counter.h | 62 ++++++++++++++++------------------
> 2 files changed, 33 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> index c533a6ff12cf..3cda2c47bacb 100644
> --- a/drivers/counter/counter-core.c
> +++ b/drivers/counter/counter-core.c
> @@ -38,6 +38,9 @@ static struct bus_type counter_bus_type = {
> * This function registers a Counter to the system. A sysfs "counter" directory
> * will be created and populated with sysfs attributes correlating with the
> * Counter Signals, Synapses, and Counts respectively.
> + *
> + * RETURNS:
> + * 0 on success, negative error number on failure.
> */
> int counter_register(struct counter_device *const counter)
> {
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index b69277f5c4c5..445f22d8bfe2 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -188,11 +188,10 @@ struct counter_comp {
>
> /**
> * struct counter_signal - Counter Signal node
> - * @id: unique ID used to identify signal
> - * @name: device-specific Signal name; ideally, this should match the name
> - * as it appears in the datasheet documentation
> - * @ext: optional array of Counter Signal extensions
> - * @num_ext: number of Counter Signal extensions specified in @ext
> + * @id: unique ID used to identify the Signal
> + * @name: device-specific Signal name
> + * @ext: optional array of Signal extensions
> + * @num_ext: number of Signal extensions specified in @ext
> */
> struct counter_signal {
> int id;
> @@ -206,7 +205,7 @@ struct counter_signal {
> * struct counter_synapse - Counter Synapse node
> * @actions_list: array of available action modes
> * @num_actions: number of action modes specified in @actions_list
> - * @signal: pointer to associated signal
> + * @signal: pointer to the associated Signal
> */
> struct counter_synapse {
> const enum counter_synapse_action *actions_list;
> @@ -217,15 +216,14 @@ struct counter_synapse {
>
> /**
> * struct counter_count - Counter Count node
> - * @id: unique ID used to identify Count
> - * @name: device-specific Count name; ideally, this should match
> - * the name as it appears in the datasheet documentation
> - * @functions_list: array available function modes
> + * @id: unique ID used to identify the Count
> + * @name: device-specific Count name
> + * @functions_list: array of available function modes
> * @num_functions: number of function modes specified in @functions_list
> - * @synapses: array of synapses for initialization
> - * @num_synapses: number of synapses specified in @synapses
> - * @ext: optional array of Counter Count extensions
> - * @num_ext: number of Counter Count extensions specified in @ext
> + * @synapses: array of Synapses for initialization
> + * @num_synapses: number of Synapses specified in @synapses
> + * @ext: optional array of Count extensions
> + * @num_ext: number of Count extensions specified in @ext
> */
> struct counter_count {
> int id;
> @@ -243,27 +241,27 @@ struct counter_count {
>
> /**
> * struct counter_ops - Callbacks from driver
> - * @signal_read: optional read callback for Signal attribute. The read
> - * level of the respective Signal should be passed back via
> - * the level parameter.
> - * @count_read: optional read callback for Count attribute. The read
> - * value of the respective Count should be passed back via
> - * the val parameter.
> - * @count_write: optional write callback for Count attribute. The write
> - * value for the respective Count is passed in via the val
> + * @signal_read: optional read callback for Signals. The read level of
> + * the respective Signal should be passed back via the
> + * level parameter.
> + * @count_read: read callback for Counts. The read value of the
> + * respective Count should be passed back via the value
> + * parameter.
> + * @count_write: optional write callback for Counts. The write value for
> + * the respective Count is passed in via the value
> * parameter.
> * @function_read: read callback the Count function modes. The read
> * function mode of the respective Count should be passed
> * back via the function parameter.
> - * @function_write: write callback for Count function modes. The function
> - * mode to write for the respective Count is passed in via
> - * the function parameter.
> - * @action_read: read callback the Synapse action modes. The read action
> - * mode of the respective Synapse should be passed back via
> - * the action parameter.
> - * @action_write: write callback for Synapse action modes. The action mode
> - * to write for the respective Synapse is passed in via the
> - * action parameter.
> + * @function_write: optional write callback for Count function modes. The
> + * function mode to write for the respective Count is
> + * passed in via the function parameter.
> + * @action_read: optional read callback the Synapse action modes. The
> + * read action mode of the respective Synapse should be
> + * passed back via the action parameter.
> + * @action_write: optional write callback for Synapse action modes. The
> + * action mode to write for the respective Synapse is
> + * passed in via the action parameter.
> */
> struct counter_ops {
> int (*signal_read)(struct counter_device *counter,
> @@ -291,7 +289,7 @@ struct counter_ops {
>
> /**
> * struct counter_device - Counter data structure
> - * @name: name of the device as it appears in the datasheet
> + * @name: name of the device
> * @parent: optional parent device providing the counters
> * @ops: callbacks from driver
> * @signals: array of Signals
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 05/14] docs: counter: Update to reflect sysfs internalization
2021-08-27 3:47 ` [PATCH v16 05/14] docs: counter: Update " William Breathitt Gray
@ 2021-09-08 17:48 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-08 17:48 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On Fri, 27 Aug 2021 12:47:49 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> The Counter subsystem architecture and driver implementations have
> changed in order to handle Counter sysfs interactions in a more
> consistent way. This patch updates the Generic Counter interface
> documentation to reflect the changes.
>
> Reviewed-by: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.
I'm going to pause at this point. We are early in the cycle anyway
so there is no rush and I'd like to take another look at the remainder
of the series + leave a little longer for others to take a look at it!
Thanks,
Jonathan
> ---
> Documentation/ABI/testing/sysfs-bus-counter | 9 +-
> Documentation/driver-api/generic-counter.rst | 243 ++++++++++++++-----
> 2 files changed, 185 insertions(+), 67 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 20fe5afd4f9e..dee79b606847 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -286,7 +286,14 @@ What: /sys/bus/counter/devices/counterX/signalY/signal
> KernelVersion: 5.2
> Contact: linux-iio@vger.kernel.org
> Description:
> - Signal data of Signal Y represented as a string.
> + Signal level state of Signal Y. The following signal level
> + states are available:
> +
> + low:
> + Low level state.
> +
> + high:
> + High level state.
>
> What: /sys/bus/counter/devices/counterX/signalY/synchronous_mode
> KernelVersion: 5.2
> diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
> index 64fe7db080e5..f6397218aa4c 100644
> --- a/Documentation/driver-api/generic-counter.rst
> +++ b/Documentation/driver-api/generic-counter.rst
> @@ -250,8 +250,8 @@ for defining a counter device.
> .. kernel-doc:: drivers/counter/counter.c
> :export:
>
> -Implementation
> -==============
> +Driver Implementation
> +=====================
>
> To support a counter device, a driver must first allocate the available
> Counter Signals via counter_signal structures. These Signals should
> @@ -267,25 +267,61 @@ respective counter_count structure. These counter_count structures are
> set to the counts array member of an allocated counter_device structure
> before the Counter is registered to the system.
>
> -Driver callbacks should be provided to the counter_device structure via
> -a constant counter_ops structure in order to communicate with the
> -device: to read and write various Signals and Counts, and to set and get
> -the "action mode" and "function mode" for various Synapses and Counts
> -respectively.
> +Driver callbacks must be provided to the counter_device structure in
> +order to communicate with the device: to read and write various Signals
> +and Counts, and to set and get the "action mode" and "function mode" for
> +various Synapses and Counts respectively.
>
> A defined counter_device structure may be registered to the system by
> passing it to the counter_register function, and unregistered by passing
> it to the counter_unregister function. Similarly, the
> -devm_counter_register and devm_counter_unregister functions may be used
> -if device memory-managed registration is desired.
> -
> -Extension sysfs attributes can be created for auxiliary functionality
> -and data by passing in defined counter_device_ext, counter_count_ext,
> -and counter_signal_ext structures. In these cases, the
> -counter_device_ext structure is used for global/miscellaneous exposure
> -and configuration of the respective Counter device, while the
> -counter_count_ext and counter_signal_ext structures allow for auxiliary
> -exposure and configuration of a specific Count or Signal respectively.
> +devm_counter_register function may be used if device memory-managed
> +registration is desired.
> +
> +The struct counter_comp structure is used to define counter extensions
> +for Signals, Synapses, and Counts.
> +
> +The "type" member specifies the type of high-level data (e.g. BOOL,
> +COUNT_DIRECTION, etc.) handled by this extension. The "``*_read``" and
> +"``*_write``" members can then be set by the counter device driver with
> +callbacks to handle that data using native C data types (i.e. u8, u64,
> +etc.).
> +
> +Convenience macros such as ``COUNTER_COMP_COUNT_U64`` are provided for
> +use by driver authors. In particular, driver authors are expected to use
> +the provided macros for standard Counter subsystem attributes in order
> +to maintain a consistent interface for userspace. For example, a counter
> +device driver may define several standard attributes like so::
> +
> + struct counter_comp count_ext[] = {
> + COUNTER_COMP_DIRECTION(count_direction_read),
> + COUNTER_COMP_ENABLE(count_enable_read, count_enable_write),
> + COUNTER_COMP_CEILING(count_ceiling_read, count_ceiling_write),
> + };
> +
> +This makes it simple to see, add, and modify the attributes that are
> +supported by this driver ("direction", "enable", and "ceiling") and to
> +maintain this code without getting lost in a web of struct braces.
> +
> +Callbacks must match the function type expected for the respective
> +component or extension. These function types are defined in the struct
> +counter_comp structure as the "``*_read``" and "``*_write``" union
> +members.
> +
> +The corresponding callback prototypes for the extensions mentioned in
> +the previous example above would be::
> +
> + int count_direction_read(struct counter_device *counter,
> + struct counter_count *count,
> + enum counter_count_direction *direction);
> + int count_enable_read(struct counter_device *counter,
> + struct counter_count *count, u8 *enable);
> + int count_enable_write(struct counter_device *counter,
> + struct counter_count *count, u8 enable);
> + int count_ceiling_read(struct counter_device *counter,
> + struct counter_count *count, u64 *ceiling);
> + int count_ceiling_write(struct counter_device *counter,
> + struct counter_count *count, u64 ceiling);
>
> Determining the type of extension to create is a matter of scope.
>
> @@ -313,52 +349,127 @@ Determining the type of extension to create is a matter of scope.
> chip overheated via a device extension called "error_overtemp":
> /sys/bus/counter/devices/counterX/error_overtemp
>
> -Architecture
> -============
> -
> -When the Generic Counter interface counter module is loaded, the
> -counter_init function is called which registers a bus_type named
> -"counter" to the system. Subsequently, when the module is unloaded, the
> -counter_exit function is called which unregisters the bus_type named
> -"counter" from the system.
> -
> -Counter devices are registered to the system via the counter_register
> -function, and later removed via the counter_unregister function. The
> -counter_register function establishes a unique ID for the Counter
> -device and creates a respective sysfs directory, where X is the
> -mentioned unique ID:
> -
> - /sys/bus/counter/devices/counterX
> -
> -Sysfs attributes are created within the counterX directory to expose
> -functionality, configurations, and data relating to the Counts, Signals,
> -and Synapses of the Counter device, as well as options and information
> -for the Counter device itself.
> -
> -Each Signal has a directory created to house its relevant sysfs
> -attributes, where Y is the unique ID of the respective Signal:
> -
> - /sys/bus/counter/devices/counterX/signalY
> -
> -Similarly, each Count has a directory created to house its relevant
> -sysfs attributes, where Y is the unique ID of the respective Count:
> -
> - /sys/bus/counter/devices/counterX/countY
> -
> -For a more detailed breakdown of the available Generic Counter interface
> -sysfs attributes, please refer to the
> -Documentation/ABI/testing/sysfs-bus-counter file.
> -
> -The Signals and Counts associated with the Counter device are registered
> -to the system as well by the counter_register function. The
> -signal_read/signal_write driver callbacks are associated with their
> -respective Signal attributes, while the count_read/count_write and
> -function_get/function_set driver callbacks are associated with their
> -respective Count attributes; similarly, the same is true for the
> -action_get/action_set driver callbacks and their respective Synapse
> -attributes. If a driver callback is left undefined, then the respective
> -read/write permission is left disabled for the relevant attributes.
> -
> -Similarly, extension sysfs attributes are created for the defined
> -counter_device_ext, counter_count_ext, and counter_signal_ext
> -structures that are passed in.
> +Subsystem Architecture
> +======================
> +
> +Counter drivers pass and take data natively (i.e. ``u8``, ``u64``, etc.)
> +and the shared counter module handles the translation between the sysfs
> +interface. This guarantees a standard userspace interface for all
> +counter drivers, and enables a Generic Counter chrdev interface via a
> +generalized device driver ABI.
> +
> +A high-level view of how a count value is passed down from a counter
> +driver is exemplified by the following. The driver callbacks are first
> +registered to the Counter core component for use by the Counter
> +userspace interface components::
> +
> + Driver callbacks registration:
> + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + +----------------------------+
> + | Counter device driver |
> + +----------------------------+
> + | Processes data from device |
> + +----------------------------+
> + |
> + -------------------
> + / driver callbacks /
> + -------------------
> + |
> + V
> + +----------------------+
> + | Counter core |
> + +----------------------+
> + | Routes device driver |
> + | callbacks to the |
> + | userspace interfaces |
> + +----------------------+
> + |
> + -------------------
> + / driver callbacks /
> + -------------------
> + |
> + +---------------+
> + |
> + V
> + +--------------------+
> + | Counter sysfs |
> + +--------------------+
> + | Translates to the |
> + | standard Counter |
> + | sysfs output |
> + +--------------------+
> +
> +Thereafter, data can be transferred directly between the Counter device
> +driver and Counter userspace interface::
> +
> + Count data request:
> + ~~~~~~~~~~~~~~~~~~~
> + ----------------------
> + / Counter device \
> + +----------------------+
> + | Count register: 0x28 |
> + +----------------------+
> + |
> + -----------------
> + / raw count data /
> + -----------------
> + |
> + V
> + +----------------------------+
> + | Counter device driver |
> + +----------------------------+
> + | Processes data from device |
> + |----------------------------|
> + | Type: u64 |
> + | Value: 42 |
> + +----------------------------+
> + |
> + ----------
> + / u64 /
> + ----------
> + |
> + +---------------+
> + |
> + V
> + +--------------------+
> + | Counter sysfs |
> + +--------------------+
> + | Translates to the |
> + | standard Counter |
> + | sysfs output |
> + |--------------------|
> + | Type: const char * |
> + | Value: "42" |
> + +--------------------+
> + |
> + ---------------
> + / const char * /
> + ---------------
> + |
> + V
> + +--------------------------------------------------+
> + | `/sys/bus/counter/devices/counterX/countY/count` |
> + +--------------------------------------------------+
> + \ Count: "42" /
> + --------------------------------------------------
> +
> +There are three primary components involved:
> +
> +Counter device driver
> +---------------------
> +Communicates with the hardware device to read/write data; e.g. counter
> +drivers for quadrature encoders, timers, etc.
> +
> +Counter core
> +------------
> +Registers the counter device driver to the system so that the respective
> +callbacks are called during userspace interaction.
> +
> +Counter sysfs
> +-------------
> +Translates counter data to the standard Counter sysfs interface format
> +and vice versa.
> +
> +Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
> +for a detailed breakdown of the available Generic Counter interface
> +sysfs attributes.
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 08/14] docs: counter: Document character device interface
2021-08-27 3:47 ` [PATCH v16 08/14] docs: counter: Document " William Breathitt Gray
@ 2021-09-12 16:18 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-12 16:18 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On Fri, 27 Aug 2021 12:47:52 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> This patch adds high-level documentation about the Counter subsystem
> character device interface.
>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
One trivial suggestion inline. This document is very good.
Jonathan
> ---
> Documentation/driver-api/generic-counter.rst | 177 ++++++++++++++----
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> 2 files changed, 137 insertions(+), 41 deletions(-)
>
> diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
> index f6397218aa4c..6ecb5d1942c7 100644
> --- a/Documentation/driver-api/generic-counter.rst
> +++ b/Documentation/driver-api/generic-counter.rst
> @@ -223,19 +223,6 @@ whether an input line is differential or single-ended) and instead focus
> on the core idea of what the data and process represent (e.g. position
> as interpreted from quadrature encoding data).
>
> -Userspace Interface
> -===================
> -
> -Several sysfs attributes are generated by the Generic Counter interface,
> -and reside under the /sys/bus/counter/devices/counterX directory, where
> -counterX refers to the respective counter device. Please see
> -Documentation/ABI/testing/sysfs-bus-counter for detailed
> -information on each Generic Counter interface sysfs attribute.
> -
> -Through these sysfs attributes, programs and scripts may interact with
> -the Generic Counter paradigm Counts, Signals, and Synapses of respective
> -counter devices.
> -
> Driver API
> ==========
>
> @@ -388,16 +375,16 @@ userspace interface components::
> / driver callbacks /
> -------------------
> |
> - +---------------+
> - |
> - V
> - +--------------------+
> - | Counter sysfs |
> - +--------------------+
> - | Translates to the |
> - | standard Counter |
> - | sysfs output |
> - +--------------------+
> + +---------------+---------------+
> + | |
> + V V
> + +--------------------+ +---------------------+
> + | Counter sysfs | | Counter chrdev |
> + +--------------------+ +---------------------+
> + | Translates to the | | Translates to the |
> + | standard Counter | | standard Counter |
> + | sysfs output | | character device |
> + +--------------------+ +---------------------+
>
> Thereafter, data can be transferred directly between the Counter device
> driver and Counter userspace interface::
> @@ -428,23 +415,30 @@ driver and Counter userspace interface::
> / u64 /
> ----------
> |
> - +---------------+
> - |
> - V
> - +--------------------+
> - | Counter sysfs |
> - +--------------------+
> - | Translates to the |
> - | standard Counter |
> - | sysfs output |
> - |--------------------|
> - | Type: const char * |
> - | Value: "42" |
> - +--------------------+
> - |
> - ---------------
> - / const char * /
> - ---------------
> + +---------------+---------------+
> + | |
> + V V
> + +--------------------+ +---------------------+
> + | Counter sysfs | | Counter chrdev |
> + +--------------------+ +---------------------+
> + | Translates to the | | Translates to the |
> + | standard Counter | | standard Counter |
> + | sysfs output | | character device |
> + |--------------------| |---------------------|
> + | Type: const char * | | Type: u64 |
> + | Value: "42" | | Value: 42 |
> + +--------------------+ +---------------------+
> + | |
> + --------------- -----------------------
> + / const char * / / struct counter_event /
> + --------------- -----------------------
> + | |
> + | V
> + | +-----------+
> + | | read |
> + | +-----------+
> + | \ Count: 42 /
> + | -----------
> |
> V
> +--------------------------------------------------+
> @@ -453,7 +447,7 @@ driver and Counter userspace interface::
> \ Count: "42" /
> --------------------------------------------------
>
> -There are three primary components involved:
> +There are four primary components involved:
>
> Counter device driver
> ---------------------
> @@ -473,3 +467,104 @@ and vice versa.
> Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
> for a detailed breakdown of the available Generic Counter interface
> sysfs attributes.
> +
> +Counter chrdev
> +--------------
> +Translates counter data to the standard Counter character device; data
Whilst it is clear when you read on, perhaps change "data" to "Counter
events" here.
> +is transferred via standard character device read calls, while Counter
> +events are configured via ioctl calls.
> +
> +Sysfs Interface
> +===============
> +
> +Several sysfs attributes are generated by the Generic Counter interface,
> +and reside under the ``/sys/bus/counter/devices/counterX`` directory,
> +where ``X`` is to the respective counter device id. Please see
> +``Documentation/ABI/testing/sysfs-bus-counter`` for detailed information
> +on each Generic Counter interface sysfs attribute.
> +
> +Through these sysfs attributes, programs and scripts may interact with
> +the Generic Counter paradigm Counts, Signals, and Synapses of respective
> +counter devices.
> +
> +Counter Character Device
> +========================
> +
> +Counter character device nodes are created under the ``/dev`` directory
> +as ``counterX``, where ``X`` is the respective counter device id.
> +Defines for the standard Counter data types are exposed via the
> +userspace ``include/uapi/linux/counter.h`` file.
> +
> +Counter events
> +--------------
> +Counter device drivers can support Counter events by utilizing the
> +``counter_push_event`` function::
> +
> + void counter_push_event(struct counter_device *const counter, const u8 event,
> + const u8 channel);
> +
> +The event id is specified by the ``event`` parameter; the event channel
> +id is specified by the ``channel`` parameter. When this function is
> +called, the Counter data associated with the respective event is
> +gathered, and a ``struct counter_event`` is generated for each datum and
> +pushed to userspace.
> +
> +Counter events can be configured by users to report various Counter
> +data of interest. This can be conceptualized as a list of Counter
> +component read calls to perform. For example:
> +
> + +------------------------+------------------------+
> + | COUNTER_EVENT_OVERFLOW | COUNTER_EVENT_INDEX |
> + +========================+========================+
> + | Channel 0 | Channel 0 |
> + +------------------------+------------------------+
> + | * Count 0 | * Signal 0 |
> + | * Count 1 | * Signal 0 Extension 0 |
> + | * Signal 3 | * Extension 4 |
> + | * Count 4 Extension 2 +------------------------+
> + | * Signal 5 Extension 0 | Channel 1 |
> + | +------------------------+
> + | | * Signal 4 |
> + | | * Signal 4 Extension 0 |
> + | | * Count 7 |
> + +------------------------+------------------------+
> +
> +When ``counter_push_event(counter, COUNTER_EVENT_INDEX, 1)`` is called
> +for example, it will go down the list for the ``COUNTER_EVENT_INDEX``
> +event channel 1 and execute the read callbacks for Signal 4, Signal 4
> +Extension 0, and Count 7 -- the data returned for each is pushed to a
> +kfifo as a ``struct counter_event``, which userspace can retrieve via a
> +standard read operation on the respective character device node.
> +
> +Userspace
> +---------
> +Userspace applications can configure Counter events via ioctl operations
> +on the Counter character device node. There following ioctl codes are
> +supported and provided by the ``linux/counter.h`` userspace header file:
> +
> +* :c:macro:`COUNTER_ADD_WATCH_IOCTL`
> +
> +* :c:macro:`COUNTER_ENABLE_EVENTS_IOCTL`
> +
> +* :c:macro:`COUNTER_DISABLE_EVENTS_IOCTL`
> +
> +To configure events to gather Counter data, users first populate a
> +``struct counter_watch`` with the relevant event id, event channel id,
> +and the information for the desired Counter component from which to
> +read, and then pass it via the ``COUNTER_ADD_WATCH_IOCTL`` ioctl
> +command.
> +
> +Note that an event can be watched without gathering Counter data by
> +setting the ``component.type`` member equal to
> +``COUNTER_COMPONENT_NONE``. With this configuration the Counter
> +character device will simply populate the event timestamps for those
> +respective ``struct counter_event`` elements and ignore the component
> +value.
> +
> +The ``COUNTER_ADD_WATCH_IOCTL`` command will buffer these Counter
> +watches. When ready, the ``COUNTER_ENABLE_EVENTS_IOCTL`` ioctl command
> +may be used to activate these Counter watches.
> +
> +Userspace applications can then execute a ``read`` operation (optionally
> +calling ``poll`` first) on the Counter character device node to retrieve
> +``struct counter_event`` elements with the desired data.
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 1409e40e6345..fc4ccc79b1b8 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -88,6 +88,7 @@ Code Seq# Include File Comments
> <http://infiniband.sourceforge.net/>
> 0x20 all drivers/cdrom/cm206.h
> 0x22 all scsi/sg.h
> +0x3E 00-0F linux/counter.h <mailto:linux-iio@vger.kernel.org>
> '!' 00-1F uapi/linux/seccomp.h
> '#' 00-3F IEEE 1394 Subsystem
> Block for the entire subsystem
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-08-27 3:47 ` [PATCH v16 07/14] counter: Add character device interface William Breathitt Gray
@ 2021-09-12 16:18 ` Jonathan Cameron
2021-09-20 10:09 ` William Breathitt Gray
0 siblings, 1 reply; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-12 16:18 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
On Fri, 27 Aug 2021 12:47:51 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> This patch introduces a character device interface for the Counter
> subsystem. Device data is exposed through standard character device read
> operations. Device data is gathered when a Counter event is pushed by
> the respective Counter device driver. Configuration is handled via ioctl
> operations on the respective Counter character device node.
>
> Cc: David Lechner <david@lechnology.com>
> Cc: Gwendal Grignou <gwendal@chromium.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Hi William,
Why the bit based lock? It feels like a mutex_trylock() type approach or
spinlock_trylock() would be a more common solution to this problem.
There is precedence for doing what you have here though so I'm not that
worried about it.
There are a few more things inline.
I've now been through this patch with as fine toothed comb as I'm likely to
do so. Hence I won't do another review unless there are substantial changes.
I nearly applied it as it stands, but given we aren't in a rush (merge window
open), it's worth just a little more time to tidy up loose ends.
Jonathan
> ---
> drivers/counter/Makefile | 2 +-
> drivers/counter/counter-chrdev.c | 553 +++++++++++++++++++++++++++++++
> drivers/counter/counter-chrdev.h | 14 +
> drivers/counter/counter-core.c | 60 +++-
> include/linux/counter.h | 51 +++
> include/uapi/linux/counter.h | 98 ++++++
> 6 files changed, 770 insertions(+), 8 deletions(-)
> create mode 100644 drivers/counter/counter-chrdev.c
> create mode 100644 drivers/counter/counter-chrdev.h
>
> diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> index 1ab7e087fdc2..8fde6c100ebc 100644
> --- a/drivers/counter/Makefile
> +++ b/drivers/counter/Makefile
> @@ -4,7 +4,7 @@
> #
>
> obj-$(CONFIG_COUNTER) += counter.o
> -counter-y := counter-core.o counter-sysfs.o
> +counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
>
> obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
> obj-$(CONFIG_INTERRUPT_CNT) += interrupt-cnt.o
> diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> new file mode 100644
> index 000000000000..30659b67d8f3
> --- /dev/null
> +++ b/drivers/counter/counter-chrdev.c
> @@ -0,0 +1,553 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Generic Counter character device interface
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#include <linux/bitops.h>
> +#include <linux/cdev.h>
> +#include <linux/counter.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/export.h>
> +#include <linux/fs.h>
> +#include <linux/kfifo.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <linux/nospec.h>
> +#include <linux/poll.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/timekeeping.h>
> +#include <linux/types.h>
> +#include <linux/uaccess.h>
> +#include <linux/wait.h>
> +
> +#include "counter-chrdev.h"
> +
> +struct counter_comp_node {
> + struct list_head l;
> + struct counter_component component;
> + struct counter_comp comp;
> + void *parent;
> +};
> +
> +static ssize_t counter_chrdev_read(struct file *filp, char __user *buf,
> + size_t len, loff_t *f_ps)
> +{
> + struct counter_device *const counter = filp->private_data;
> + int err;
> + unsigned int copied;
> +
> + if (!counter->ops)
> + return -ENODEV;
> +
> + if (len < sizeof(struct counter_event))
> + return -EINVAL;
> +
> + do {
> + if (kfifo_is_empty(&counter->events)) {
> + if (filp->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> +
> + err = wait_event_interruptible(counter->events_wait,
> + !kfifo_is_empty(&counter->events) ||
> + !counter->ops);
> + if (err < 0)
> + return err;
> + if (!counter->ops)
> + return -ENODEV;
> + }
> +
> + if (mutex_lock_interruptible(&counter->events_lock))
> + return -ERESTARTSYS;
> + err = kfifo_to_user(&counter->events, buf, len, &copied);
> + mutex_unlock(&counter->events_lock);
> + if (err < 0)
> + return err;
> + } while (!copied);
> +
> + return copied;
> +}
> +
> +static __poll_t counter_chrdev_poll(struct file *filp,
> + struct poll_table_struct *pollt)
> +{
> + struct counter_device *const counter = filp->private_data;
> + __poll_t events = 0;
> +
> + if (!counter->ops)
> + return events;
> +
> + poll_wait(filp, &counter->events_wait, pollt);
> +
> + if (!kfifo_is_empty(&counter->events))
> + events = EPOLLIN | EPOLLRDNORM;
> +
> + return events;
> +}
> +
> +static void counter_events_list_free(struct list_head *const events_list)
> +{
> + struct counter_event_node *p, *n;
> + struct counter_comp_node *q, *o;
> +
> + list_for_each_entry_safe(p, n, events_list, l) {
> + /* Free associated component nodes */
> + list_for_each_entry_safe(q, o, &p->comp_list, l) {
> + list_del(&q->l);
> + kfree(q);
> + }
> +
> + /* Free event node */
> + list_del(&p->l);
> + kfree(p);
> + }
> +}
> +
> +static int counter_set_event_node(struct counter_device *const counter,
> + struct counter_watch *const watch,
> + const struct counter_comp_node *const cfg)
> +{
> + struct counter_event_node *event_node;
> + int err = 0;
> + struct counter_comp_node *comp_node;
> +
> + /* Search for event in the list */
> + list_for_each_entry(event_node, &counter->next_events_list, l)
> + if (event_node->event == watch->event &&
> + event_node->channel == watch->channel)
> + break;
> +
> + /* If event is not already in the list */
> + if (&event_node->l == &counter->next_events_list) {
> + /* Allocate new event node */
> + event_node = kmalloc(sizeof(*event_node), GFP_KERNEL);
> + if (!event_node)
> + return -ENOMEM;
> +
> + /* Configure event node and add to the list */
> + event_node->event = watch->event;
> + event_node->channel = watch->channel;
> + INIT_LIST_HEAD(&event_node->comp_list);
> + list_add(&event_node->l, &counter->next_events_list);
> + }
> +
> + /* Check if component watch has already been set before */
> + list_for_each_entry(comp_node, &event_node->comp_list, l)
> + if (comp_node->parent == cfg->parent &&
> + comp_node->comp.count_u8_read == cfg->comp.count_u8_read) {
> + err = -EINVAL;
> + goto exit_free_event_node;
> + }
> +
> + /* Allocate component node */
> + comp_node = kmalloc(sizeof(*comp_node), GFP_KERNEL);
> + if (!comp_node) {
> + err = -ENOMEM;
> + goto exit_free_event_node;
> + }
> + *comp_node = *cfg;
> +
> + /* Add component node to event node */
> + list_add_tail(&comp_node->l, &event_node->comp_list);
> +
> +exit_free_event_node:
> + /* Free event node if no one else is watching */
> + if (list_empty(&event_node->comp_list)) {
> + list_del(&event_node->l);
> + kfree(event_node);
> + }
> +
> + return err;
> +}
> +
> +static int counter_enable_events(struct counter_device *const counter)
> +{
> + unsigned long flags;
> + int err = 0;
> +
> + mutex_lock(&counter->n_events_list_lock);
> + spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> + counter_events_list_free(&counter->events_list);
> + list_replace_init(&counter->next_events_list,
> + &counter->events_list);
> +
> + if (counter->ops->events_configure)
> + err = counter->ops->events_configure(counter);
> +
> + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> + mutex_unlock(&counter->n_events_list_lock);
> +
> + return err;
> +}
> +
> +static int counter_disable_events(struct counter_device *const counter)
> +{
> + unsigned long flags;
> + int err = 0;
> +
> + spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> + counter_events_list_free(&counter->events_list);
> +
> + if (counter->ops->events_configure)
> + err = counter->ops->events_configure(counter);
> +
> + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> +
> + mutex_lock(&counter->n_events_list_lock);
> +
> + counter_events_list_free(&counter->next_events_list);
> +
> + mutex_unlock(&counter->n_events_list_lock);
> +
> + return err;
> +}
> +
> +static int counter_add_watch(struct counter_device *const counter,
> + const unsigned long arg)
> +{
> + void __user *const uwatch = (void __user *)arg;
> + struct counter_watch watch;
> + struct counter_comp_node comp_node = {};
> + size_t parent, id;
> + struct counter_comp *ext;
> + size_t num_ext;
> + int err = 0;
> +
> + if (copy_from_user(&watch, uwatch, sizeof(watch)))
> + return -EFAULT;
> +
> + if (watch.component.type == COUNTER_COMPONENT_NONE)
> + goto no_component;
> +
> + parent = watch.component.parent;
> +
> + /* Configure parent component info for comp node */
> + switch (watch.component.scope) {
> + case COUNTER_SCOPE_DEVICE:
> + ext = counter->ext;
> + num_ext = counter->num_ext;
> + break;
> + case COUNTER_SCOPE_SIGNAL:
> + if (parent >= counter->num_signals)
> + return -EINVAL;
> + parent = array_index_nospec(parent, counter->num_signals);
> +
> + comp_node.parent = counter->signals + parent;
> +
> + ext = counter->signals[parent].ext;
> + num_ext = counter->signals[parent].num_ext;
> + break;
> + case COUNTER_SCOPE_COUNT:
> + if (parent >= counter->num_counts)
> + return -EINVAL;
> + parent = array_index_nospec(parent, counter->num_counts);
> +
> + comp_node.parent = counter->counts + parent;
> +
> + ext = counter->counts[parent].ext;
> + num_ext = counter->counts[parent].num_ext;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + id = watch.component.id;
> +
> + /* Configure component info for comp node */
> + switch (watch.component.type) {
> + case COUNTER_COMPONENT_SIGNAL:
> + if (watch.component.scope != COUNTER_SCOPE_SIGNAL)
> + return -EINVAL;
> +
> + comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL;
> + comp_node.comp.signal_u32_read = counter->ops->signal_read;
> + break;
> + case COUNTER_COMPONENT_COUNT:
> + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> + return -EINVAL;
> +
> + comp_node.comp.type = COUNTER_COMP_U64;
> + comp_node.comp.count_u64_read = counter->ops->count_read;
> + break;
> + case COUNTER_COMPONENT_FUNCTION:
> + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> + return -EINVAL;
> +
> + comp_node.comp.type = COUNTER_COMP_FUNCTION;
> + comp_node.comp.count_u32_read = counter->ops->function_read;
> + break;
> + case COUNTER_COMPONENT_SYNAPSE_ACTION:
> + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> + return -EINVAL;
> + if (id >= counter->counts[parent].num_synapses)
> + return -EINVAL;
> + id = array_index_nospec(id, counter->counts[parent].num_synapses);
> +
> + comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION;
> + comp_node.comp.action_read = counter->ops->action_read;
> + comp_node.comp.priv = counter->counts[parent].synapses + id;
> + break;
> + case COUNTER_COMPONENT_EXTENSION:
> + if (id >= num_ext)
> + return -EINVAL;
> + id = array_index_nospec(id, num_ext);
> +
> + comp_node.comp = ext[id];
> + break;
> + default:
> + return -EINVAL;
> + }
> + /* Check if any read callback is set; this is part of a union */
> + if (!comp_node.comp.count_u8_read)
This isn't valid for C. The compiler is allowed to treat the elements
of a union as not being in the same memory etc unless they are of the same
type (which isn't true here - I think anyway)...
So whilst it seems silly you need to check all the callbacks in this if
statement. It will 'almost' always work as you have it, but it's possible
some future optimisation by the compiler will mean that u8_read would be
set by this point, but it delayed setting e.g. u32_read until after
this check.
> + return -EOPNOTSUPP;
> +
> +no_component:
> + mutex_lock(&counter->n_events_list_lock);
> +
> + if (counter->ops->watch_validate) {
> + err = counter->ops->watch_validate(counter, &watch);
> + if (err < 0)
> + goto err_exit;
> + }
> +
> + comp_node.component = watch.component;
> +
> + err = counter_set_event_node(counter, &watch, &comp_node);
> +
> +err_exit:
> + mutex_unlock(&counter->n_events_list_lock);
> +
> + return err;
> +}
> +
> +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd,
> + unsigned long arg)
> +{
> + struct counter_device *const counter = filp->private_data;
> + int ret = -ENODEV;
> +
> + mutex_lock(&counter->ops_exist_lock);
> +
> + if (!counter->ops)
> + goto out_unlock;
> +
> + switch (cmd) {
> + case COUNTER_ADD_WATCH_IOCTL:
> + ret = counter_add_watch(counter, arg);
> + break;
> + case COUNTER_ENABLE_EVENTS_IOCTL:
> + ret = counter_enable_events(counter);
> + break;
> + case COUNTER_DISABLE_EVENTS_IOCTL:
> + ret = counter_disable_events(counter);
> + break;
> + default:
> + ret = -ENOIOCTLCMD;
> + break;
> + }
> +
> +out_unlock:
> + mutex_unlock(&counter->ops_exist_lock);
> +
> + return ret;
> +}
> +
> +static int counter_chrdev_open(struct inode *inode, struct file *filp)
> +{
> + struct counter_device *const counter = container_of(inode->i_cdev,
> + typeof(*counter),
> + chrdev);
> +
> + if (test_and_set_bit_lock(0, counter->chrdev_lock))
> + return -EBUSY;
> +
> + get_device(&counter->dev);
> + filp->private_data = counter;
> +
> + return nonseekable_open(inode, filp);
> +}
> +
> +static int counter_chrdev_release(struct inode *inode, struct file *filp)
> +{
> + struct counter_device *const counter = filp->private_data;
> + int ret = 0;
> +
> + mutex_lock(&counter->ops_exist_lock);
> +
> + if (!counter->ops) {
This needs a comment to explain how you would get here and
why these two lists need cleaning up here if we do.
Superficially it feels to me like you could just add a counter->ops check in
counter_disable_events() and then call that directly. I'm guessing
I am missing a deadlock or similar however.
> + counter_events_list_free(&counter->events_list);
> + counter_events_list_free(&counter->next_events_list);
> + ret = -ENODEV;
> + goto out_unlock;
> + }
> +
> + ret = counter_disable_events(counter);
> + if (ret < 0) {
> + mutex_unlock(&counter->ops_exist_lock);
> + return ret;
> + }
> +
> +out_unlock:
> + mutex_unlock(&counter->ops_exist_lock);
> +
> + put_device(&counter->dev);
> + clear_bit_unlock(0, counter->chrdev_lock);
> +
> + return ret;
> +}
> +
> +static const struct file_operations counter_fops = {
> + .owner = THIS_MODULE,
> + .llseek = no_llseek,
> + .read = counter_chrdev_read,
> + .poll = counter_chrdev_poll,
> + .unlocked_ioctl = counter_chrdev_ioctl,
> + .open = counter_chrdev_open,
> + .release = counter_chrdev_release,
> +};
> +
> +int counter_chrdev_add(struct counter_device *const counter)
To think about: This isn't doing the add. So would counter_chrdev_init() be more
appropriate? The fact it can fail due to the kfifo_alloc makes that
naming less than ideal though.
> +{
> + /* Initialize Counter events lists */
> + INIT_LIST_HEAD(&counter->events_list);
> + INIT_LIST_HEAD(&counter->next_events_list);
> + spin_lock_init(&counter->events_list_lock);
> + mutex_init(&counter->n_events_list_lock);
> + init_waitqueue_head(&counter->events_wait);
> + mutex_init(&counter->events_lock);
> +
> + /* Initialize character device */
> + clear_bit(0, counter->chrdev_lock);
> + cdev_init(&counter->chrdev, &counter_fops);
> +
> + /* Allocate Counter events queue */
> + return kfifo_alloc(&counter->events, 64, GFP_KERNEL);
> +}
> +
> +void counter_chrdev_remove(struct counter_device *const counter)
> +{
> + kfifo_free(&counter->events);
> +}
> +
> +static int counter_get_data(struct counter_device *const counter,
> + const struct counter_comp_node *const comp_node,
> + u64 *const value)
> +{
> + const struct counter_comp *const comp = &comp_node->comp;
> + void *const parent = comp_node->parent;
> + u8 value_u8 = 0;
> + u32 value_u32 = 0;
> + int ret;
> +
> + if (comp_node->component.type == COUNTER_COMPONENT_NONE)
> + return 0;
> +
> + switch (comp->type) {
> + case COUNTER_COMP_U8:
> + case COUNTER_COMP_BOOL:
> + switch (comp_node->component.scope) {
> + case COUNTER_SCOPE_DEVICE:
> + ret = comp->device_u8_read(counter, &value_u8);
> + break;
> + case COUNTER_SCOPE_SIGNAL:
> + ret = comp->signal_u8_read(counter, parent, &value_u8);
> + break;
> + case COUNTER_SCOPE_COUNT:
> + ret = comp->count_u8_read(counter, parent, &value_u8);
> + break;
> + }
> + *value = value_u8;
> + return ret;
> + case COUNTER_COMP_SIGNAL_LEVEL:
> + case COUNTER_COMP_FUNCTION:
> + case COUNTER_COMP_ENUM:
> + case COUNTER_COMP_COUNT_DIRECTION:
> + case COUNTER_COMP_COUNT_MODE:
> + switch (comp_node->component.scope) {
> + case COUNTER_SCOPE_DEVICE:
> + ret = comp->device_u32_read(counter, &value_u32);
> + break;
> + case COUNTER_SCOPE_SIGNAL:
> + ret = comp->signal_u32_read(counter, parent,
> + &value_u32);
> + break;
> + case COUNTER_SCOPE_COUNT:
> + ret = comp->count_u32_read(counter, parent, &value_u32);
> + break;
> + }
> + *value = value_u32;
> + return ret;
> + case COUNTER_COMP_U64:
> + switch (comp_node->component.scope) {
> + case COUNTER_SCOPE_DEVICE:
> + return comp->device_u64_read(counter, value);
> + case COUNTER_SCOPE_SIGNAL:
> + return comp->signal_u64_read(counter, parent, value);
> + case COUNTER_SCOPE_COUNT:
> + return comp->count_u64_read(counter, parent, value);
> + default:
> + return -EINVAL;
> + }
> + case COUNTER_COMP_SYNAPSE_ACTION:
> + ret = comp->action_read(counter, parent, comp->priv,
> + &value_u32);
> + *value = value_u32;
> + return ret;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +/**
> + * counter_push_event - queue event for userspace reading
> + * @counter: pointer to Counter structure
> + * @event: triggered event
> + * @channel: event channel
> + *
> + * Note: If no one is watching for the respective event, it is silently
> + * discarded.
> + */
> +void counter_push_event(struct counter_device *const counter, const u8 event,
> + const u8 channel)
> +{
> + struct counter_event ev;
> + unsigned int copied = 0;
> + unsigned long flags;
> + struct counter_event_node *event_node;
> + struct counter_comp_node *comp_node;
> +
> + ev.timestamp = ktime_get_ns();
> + ev.watch.event = event;
> + ev.watch.channel = channel;
> +
> + /* Could be in an interrupt context, so use a spin lock */
> + spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> + /* Search for event in the list */
Worth keeping in mind that searching a list is not exactly a scalable
solution even if it's fine for now.
> + list_for_each_entry(event_node, &counter->events_list, l)
> + if (event_node->event == event &&
> + event_node->channel == channel)
> + break;
> +
> + /* If event is not in the list */
> + if (&event_node->l == &counter->events_list)
> + goto exit_early;
> +
> + /* Read and queue relevant comp for userspace */
> + list_for_each_entry(comp_node, &event_node->comp_list, l) {
> + ev.watch.component = comp_node->component;
> + ev.status = -counter_get_data(counter, comp_node, &ev.value);
> +
> + copied += kfifo_in(&counter->events, &ev, 1);
I had a short debate with myself on whether this or kfifo_put() was more appropriate
(as fixed record length). I think this particular case they end up the same anyway
so it doesn't matter (nothing to do here!)
> + }
> +
> +exit_early:
> + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> +
> + if (copied)
> + wake_up_poll(&counter->events_wait, EPOLLIN);
> +}
> +EXPORT_SYMBOL_GPL(counter_push_event);
> diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
> new file mode 100644
> index 000000000000..5529d16703c4
> --- /dev/null
> +++ b/drivers/counter/counter-chrdev.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Counter character device interface
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _COUNTER_CHRDEV_H_
> +#define _COUNTER_CHRDEV_H_
> +
> +#include <linux/counter.h>
> +
> +int counter_chrdev_add(struct counter_device *const counter);
> +void counter_chrdev_remove(struct counter_device *const counter);
> +
> +#endif /* _COUNTER_CHRDEV_H_ */
> diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> index 3cda2c47bacb..28dc1ff63c94 100644
> --- a/drivers/counter/counter-core.c
> +++ b/drivers/counter/counter-core.c
> @@ -3,14 +3,22 @@
> * Generic Counter interface
> * Copyright (C) 2020 William Breathitt Gray
> */
> +#include <linux/cdev.h>
> #include <linux/counter.h>
> #include <linux/device.h>
> +#include <linux/device/bus.h>
> #include <linux/export.h>
> +#include <linux/fs.h>
> #include <linux/gfp.h>
> #include <linux/idr.h>
> #include <linux/init.h>
> +#include <linux/kdev_t.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/types.h>
> +#include <linux/wait.h>
>
> +#include "counter-chrdev.h"
> #include "counter-sysfs.h"
>
> /* Provides a unique ID for each counter device */
> @@ -18,6 +26,9 @@ static DEFINE_IDA(counter_ida);
>
> static void counter_device_release(struct device *dev)
> {
> + struct counter_device *const counter = dev_get_drvdata(dev);
> +
> + counter_chrdev_remove(counter);
> ida_free(&counter_ida, dev->id);
> }
>
> @@ -31,6 +42,8 @@ static struct bus_type counter_bus_type = {
> .dev_name = "counter",
> };
>
> +static dev_t counter_devt;
> +
> /**
> * counter_register - register Counter to the system
> * @counter: pointer to Counter to register
> @@ -53,10 +66,13 @@ int counter_register(struct counter_device *const counter)
> if (id < 0)
> return id;
>
> + mutex_init(&counter->ops_exist_lock);
> +
> /* Configure device structure for Counter */
> dev->id = id;
> dev->type = &counter_device_type;
> dev->bus = &counter_bus_type;
> + dev->devt = MKDEV(MAJOR(counter_devt), id);
> if (counter->parent) {
> dev->parent = counter->parent;
> dev->of_node = counter->parent->of_node;
> @@ -64,18 +80,22 @@ int counter_register(struct counter_device *const counter)
> device_initialize(dev);
> dev_set_drvdata(dev, counter);
>
> - /* Add Counter sysfs attributes */
> - err = counter_sysfs_add(counter);
> + err = counter_chrdev_add(counter);
> if (err < 0)
> goto err_free_id;
>
> - /* Add device to system */
> - err = device_add(dev);
> + err = counter_sysfs_add(counter);
> if (err < 0)
> - goto err_free_id;
> + goto err_remove_chrdev;
> +
> + err = cdev_device_add(&counter->chrdev, dev);
> + if (err < 0)
> + goto err_remove_chrdev;
>
> return 0;
>
> +err_remove_chrdev:
> + counter_chrdev_remove(counter);
Totally trivial, but the sysfs cleanup is managed by devm_ whilst this counter_chrdev_remove()
is manual. That leaves us in a case where the unwind order is subtly different from the
reverse of the setup order. Is there any reason to not do the sysfs part of register first
and hence have the ordering match?
> err_free_id:
> put_device(dev);
> return err;
> @@ -93,7 +113,16 @@ void counter_unregister(struct counter_device *const counter)
> if (!counter)
> return;
>
> - device_unregister(&counter->dev);
> + cdev_device_del(&counter->chrdev, &counter->dev);
> +
> + mutex_lock(&counter->ops_exist_lock);
> +
> + counter->ops = NULL;
> + wake_up(&counter->events_wait);
> +
> + mutex_unlock(&counter->ops_exist_lock);
> +
> + put_device(&counter->dev);
> }
> EXPORT_SYMBOL_GPL(counter_unregister);
>
> @@ -127,13 +156,30 @@ int devm_counter_register(struct device *dev,
> }
> EXPORT_SYMBOL_GPL(devm_counter_register);
>
> +#define COUNTER_DEV_MAX 256
> +
> static int __init counter_init(void)
> {
> - return bus_register(&counter_bus_type);
> + int err;
> +
> + err = bus_register(&counter_bus_type);
Hmm. This isn't ideal in IIO either, but logically bus_register() is the part that
exposes the infrastructure for other drivers to attach to so should be last thing
in init. However, I'm fairly sure the dependency handing will ensure this init()
is finished before it tries to register any counter drivers. Hence we are fine
anyway.
So in conclusion - nothing needs changing here...
> + if (err < 0)
> + return err;
> +
> + err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
> + if (err < 0)
> + goto err_unregister_bus;
> +
> + return 0;
> +
> +err_unregister_bus:
> + bus_unregister(&counter_bus_type);
> + return err;
> }
>
> static void __exit counter_exit(void)
> {
> + unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
> bus_unregister(&counter_bus_type);
> }
>
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index 7c9f7e23953a..9c9984655f8c 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -6,9 +6,14 @@
> #ifndef _COUNTER_H_
> #define _COUNTER_H_
>
> +#include <linux/cdev.h>
> #include <linux/device.h>
> #include <linux/kernel.h>
> +#include <linux/kfifo.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock_types.h>
> #include <linux/types.h>
> +#include <linux/wait.h>
> #include <uapi/linux/counter.h>
>
> struct counter_device;
> @@ -199,6 +204,20 @@ struct counter_count {
> size_t num_ext;
> };
>
> +/**
> + * struct counter_event_node - Counter Event node
> + * @l: list of current watching Counter events
> + * @event: event that triggers
> + * @channel: event channel
> + * @comp_list: list of components to watch when event triggers
> + */
> +struct counter_event_node {
> + struct list_head l;
> + u8 event;
> + u8 channel;
> + struct list_head comp_list;
> +};
> +
> /**
> * struct counter_ops - Callbacks from driver
> * @signal_read: optional read callback for Signals. The read level of
> @@ -222,6 +241,13 @@ struct counter_count {
> * @action_write: optional write callback for Synapse action modes. The
> * action mode to write for the respective Synapse is
> * passed in via the action parameter.
> + * @events_configure: optional write callback to configure events. The list of
> + * struct counter_event_node may be accessed via the
> + * events_list member of the counter parameter.
> + * @watch_validate: optional callback to validate a watch. The Counter
> + * component watch configuration is passed in via the watch
> + * parameter. A return value of 0 indicates a valid Counter
> + * component watch configuration.
> */
> struct counter_ops {
> int (*signal_read)(struct counter_device *counter,
> @@ -245,6 +271,9 @@ struct counter_ops {
> struct counter_count *count,
> struct counter_synapse *synapse,
> enum counter_synapse_action action);
> + int (*events_configure)(struct counter_device *counter);
> + int (*watch_validate)(struct counter_device *counter,
> + const struct counter_watch *watch);
> };
>
> /**
> @@ -260,6 +289,16 @@ struct counter_ops {
> * @num_ext: number of Counter device extensions specified in @ext
> * @priv: optional private data supplied by driver
> * @dev: internal device structure
> + * @chrdev: internal character device structure
> + * @events_list: list of current watching Counter events
> + * @events_list_lock: lock to protect Counter events list operations
> + * @next_events_list: list of next watching Counter events
> + * @n_events_list_lock: lock to protect Counter next events list operations
> + * @events: queue of detected Counter events
> + * @events_wait: wait queue to allow blocking reads of Counter events
> + * @events_lock: lock to protect Counter events queue read operations
> + * @chrdev_lock: lock to limit chrdev to a single open at a time
> + * @ops_exist_lock: lock to prevent use during removal
> */
> struct counter_device {
> const char *name;
> @@ -278,12 +317,24 @@ struct counter_device {
> void *priv;
>
> struct device dev;
> + struct cdev chrdev;
> + struct list_head events_list;
> + spinlock_t events_list_lock;
> + struct list_head next_events_list;
> + struct mutex n_events_list_lock;
> + DECLARE_KFIFO_PTR(events, struct counter_event);
> + wait_queue_head_t events_wait;
> + struct mutex events_lock;
> + DECLARE_BITMAP(chrdev_lock, 1);
Why use a bitmap for this rather than any of the other lock types?
> + struct mutex ops_exist_lock;
> };
>
> int counter_register(struct counter_device *const counter);
> void counter_unregister(struct counter_device *const counter);
> int devm_counter_register(struct device *dev,
> struct counter_device *const counter);
> +void counter_push_event(struct counter_device *const counter, const u8 event,
> + const u8 channel);
>
> #define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \
> { \
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 09/14] tools/counter: Create Counter tools
2021-08-27 3:47 ` [PATCH v16 09/14] tools/counter: Create Counter tools William Breathitt Gray
@ 2021-09-12 16:26 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-12 16:26 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Pavel Machek
On Fri, 27 Aug 2021 12:47:53 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> This creates an example Counter program under tools/counter/*
> to exemplify the Counter character device interface.
>
> Cc: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
It's great to have this example, but it very much an example rather than
a generic tool. You may want to revisit and provide a more generic
tool in the future.
A trivial comment about using a loop inline.
Jonathan
> ---
> MAINTAINERS | 1 +
> tools/Makefile | 13 ++---
> tools/counter/Build | 1 +
> tools/counter/Makefile | 53 +++++++++++++++++++
> tools/counter/counter_example.c | 93 +++++++++++++++++++++++++++++++++
> 5 files changed, 155 insertions(+), 6 deletions(-)
> create mode 100644 tools/counter/Build
> create mode 100644 tools/counter/Makefile
> create mode 100644 tools/counter/counter_example.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f2fdd2202605..57dc9b6ff82a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4782,6 +4782,7 @@ F: Documentation/driver-api/generic-counter.rst
> F: drivers/counter/
> F: include/linux/counter.h
> F: include/uapi/linux/counter.h
> +F: tools/counter/
>
> CP2615 I2C DRIVER
> M: Bence Csókás <bence98@sch.bme.hu>
> diff --git a/tools/Makefile b/tools/Makefile
> index 7e9d34ddd74c..5da1fde03a9a 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -12,6 +12,7 @@ help:
> @echo ' acpi - ACPI tools'
> @echo ' bpf - misc BPF tools'
> @echo ' cgroup - cgroup tools'
> + @echo ' counter - counter tools'
> @echo ' cpupower - a tool for all things x86 CPU power'
> @echo ' debugging - tools for debugging'
> @echo ' firewire - the userspace part of nosy, an IEEE-1394 traffic sniffer'
> @@ -65,7 +66,7 @@ acpi: FORCE
> cpupower: FORCE
> $(call descend,power/$@)
>
> -cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
> +cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
> $(call descend,$@)
>
> bpf/%: FORCE
> @@ -100,7 +101,7 @@ freefall: FORCE
> kvm_stat: FORCE
> $(call descend,kvm/$@)
>
> -all: acpi cgroup cpupower gpio hv firewire liblockdep \
> +all: acpi cgroup counter cpupower gpio hv firewire liblockdep \
> perf selftests bootconfig spi turbostat usb \
> virtio vm bpf x86_energy_perf_policy \
> tmon freefall iio objtool kvm_stat wmi \
> @@ -112,7 +113,7 @@ acpi_install:
> cpupower_install:
> $(call descend,power/$(@:_install=),install)
>
> -cgroup_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
> +cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
> $(call descend,$(@:_install=),install)
>
> liblockdep_install:
> @@ -133,7 +134,7 @@ freefall_install:
> kvm_stat_install:
> $(call descend,kvm/$(@:_install=),install)
>
> -install: acpi_install cgroup_install cpupower_install gpio_install \
> +install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
> hv_install firewire_install iio_install liblockdep_install \
> perf_install selftests_install turbostat_install usb_install \
> virtio_install vm_install bpf_install x86_energy_perf_policy_install \
> @@ -147,7 +148,7 @@ acpi_clean:
> cpupower_clean:
> $(call descend,power/cpupower,clean)
>
> -cgroup_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
> +cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
> $(call descend,$(@:_clean=),clean)
>
> liblockdep_clean:
> @@ -181,7 +182,7 @@ freefall_clean:
> build_clean:
> $(call descend,build,clean)
>
> -clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean \
> +clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
This is far from alphabetical, though I have no idea if there is any strong convention on where
to add new entries.
> perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
> vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
> freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
> diff --git a/tools/counter/Build b/tools/counter/Build
> new file mode 100644
> index 000000000000..33f4a51d715e
> --- /dev/null
> +++ b/tools/counter/Build
> @@ -0,0 +1 @@
> +counter_example-y += counter_example.o
> diff --git a/tools/counter/Makefile b/tools/counter/Makefile
> new file mode 100644
> index 000000000000..5ebc195fd9c0
> --- /dev/null
> +++ b/tools/counter/Makefile
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: GPL-2.0
> +include ../scripts/Makefile.include
> +
> +bindir ?= /usr/bin
> +
> +ifeq ($(srctree),)
> +srctree := $(patsubst %/,%,$(dir $(CURDIR)))
> +srctree := $(patsubst %/,%,$(dir $(srctree)))
> +endif
> +
> +# Do not use make's built-in rules
> +# (this improves performance and avoids hard-to-debug behaviour);
> +MAKEFLAGS += -r
> +
> +override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> +
> +ALL_TARGETS := counter_example
> +ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
> +
> +all: $(ALL_PROGRAMS)
> +
> +export srctree OUTPUT CC LD CFLAGS
> +include $(srctree)/tools/build/Makefile.include
> +
> +#
> +# We need the following to be outside of kernel tree
> +#
> +$(OUTPUT)include/linux/counter.h: ../../include/uapi/linux/counter.h
> + mkdir -p $(OUTPUT)include/linux 2>&1 || true
> + ln -sf $(CURDIR)/../../include/uapi/linux/counter.h $@
> +
> +prepare: $(OUTPUT)include/linux/counter.h
> +
> +COUNTER_EXAMPLE := $(OUTPUT)counter_example.o
> +$(COUNTER_EXAMPLE): prepare FORCE
> + $(Q)$(MAKE) $(build)=counter_example
> +$(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
> + $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
> +
> +clean:
> + rm -f $(ALL_PROGRAMS)
> + rm -rf $(OUTPUT)include/linux/counter.h
> + find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
> +
> +install: $(ALL_PROGRAMS)
> + install -d -m 755 $(DESTDIR)$(bindir); \
> + for program in $(ALL_PROGRAMS); do \
> + install $$program $(DESTDIR)$(bindir); \
> + done
> +
> +FORCE:
> +
> +.PHONY: all install clean FORCE prepare
> diff --git a/tools/counter/counter_example.c b/tools/counter/counter_example.c
> new file mode 100644
> index 000000000000..90d69fb9463b
> --- /dev/null
> +++ b/tools/counter/counter_example.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Counter - example userspace application
> + *
> + * The userspace application opens /dev/counter0, configures the
> + * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count
> + * 1 count, and prints out the data as it becomes available on the
> + * character device node.
> + *
> + * Copyright (C) 2021 William Breathitt Gray
> + */
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <linux/counter.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +static struct counter_watch watches[2] = {
> + {
> + /* Component data: Count 0 count */
> + .component.type = COUNTER_COMPONENT_COUNT,
> + .component.scope = COUNTER_SCOPE_COUNT,
> + .component.parent = 0,
> + /* Event type: Index */
> + .event = COUNTER_EVENT_INDEX,
> + /* Device event channel 0 */
> + .channel = 0,
> + },
> + {
> + /* Component data: Count 1 count */
> + .component.type = COUNTER_COMPONENT_COUNT,
> + .component.scope = COUNTER_SCOPE_COUNT,
> + .component.parent = 1,
> + /* Event type: Index */
> + .event = COUNTER_EVENT_INDEX,
> + /* Device event channel 0 */
> + .channel = 0,
> + },
> +};
> +
> +int main(void)
> +{
> + int fd;
> + int ret;
> + struct counter_event event_data[2];
> +
> + fd = open("/dev/counter0", O_RDWR);
You may want to make this tool more flexible at somepoint. It is
in tools rather than Documentation after all.
> + if (fd == -1) {
> + perror("Unable to open /dev/counter0");
> + return -errno;
> + }
> +
> + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
Loop?
> + if (ret == -1) {
> + perror("Error adding watches[0]");
> + return -errno;
> + }
> + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
> + if (ret == -1) {
> + perror("Error adding watches[1]");
> + return -errno;
> + }
> + ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
> + if (ret == -1) {
> + perror("Error enabling events");
> + return -errno;
> + }
> +
> + for (;;) {
> + ret = read(fd, event_data, sizeof(event_data));
> + if (ret == -1) {
> + perror("Failed to read event data");
> + return 1;
> + }
> +
> + if (ret != sizeof(event_data)) {
> + fprintf(stderr, "Failed to read event data\n");
> + return -EIO;
> + }
> +
> + printf("Timestamp 0: %llu\tCount 0: %llu\n"
> + "Error Message 0: %s\n"
> + "Timestamp 1: %llu\tCount 1: %llu\n"
> + "Error Message 1: %s\n",
> + event_data[0].timestamp, event_data[0].value,
> + strerror(event_data[0].status),
> + event_data[1].timestamp, event_data[1].value,
> + strerror(event_data[1].status));
> + }
> +
> + return 0;
> +}
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 00/14] Introduce the Counter character device interface
2021-08-30 17:17 ` [PATCH v16 00/14] Introduce the Counter character device interface Jonathan Cameron
@ 2021-09-12 16:36 ` Jonathan Cameron
0 siblings, 0 replies; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-12 16:36 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula
On Mon, 30 Aug 2021 18:17:06 +0100
Jonathan Cameron <jic23@kernel.org> wrote:
> On Fri, 27 Aug 2021 12:47:44 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>
> > Changes in v16:
> > - Define magic numbers for stm32-lptimer-cnt clock polarities
> > - Define magic numbers for stm32-timer-cnt encoder modes
> > - Bump KernelVersion to 5.16 in sysfs-bus-counter ABI documentation
> > - Fix typos in driver API generic-counter.rst documentation file
> >
> > For convenience, this patchset is also available on my personal git
> > repo: https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v16
> >
> > The patches preceding "counter: Internalize sysfs interface code" are
> > primarily cleanup and fixes that can be picked up and applied now to the
> > IIO tree if so desired. The "counter: Internalize sysfs interface code"
> > patch as well may be considered for pickup because it is relatively safe
> > and makes no changes to the userspace interface.
> >
> > To summarize the main points of this patchset: there are no changes to
> > the existing Counter sysfs userspace interface; a Counter character
> > device interface is introduced that allows Counter events and associated
> > data to be read() by userspace; the events_configure() and
> > watch_validate() driver callbacks are introduced to support Counter
> > events; and IRQ support is added to the 104-QUAD-8 driver, serving as an
> > example of how to support the new Counter events functionality.
>
> Hi William,
>
> I'll aim to pick up the first part in a week (too tired today after a lot
> of reviewing to even manage the basic sanity check on the changes).
>
> For the rest...
>
> What I'd really like to know is if anyone other than William and I is planning
> to review them in depth? (particularly 7 and 8 which are the new interface
> patch and docs)
>
> So if anyone reading this is in that category please let me know. We can wait,
> but conversely if no one is going to get time / inclination to do it then I
> don't want to hold these up any longer and maximum time in linux-next may
> be more useful than sitting unloved on the mailing list.
Ah well, looks like it's just the two of us for the chrdev core patches :)
Anyhow, I found time for a more thorough review. I'm not 100% convinced on
the model for the chrdev but you know a lot more about this sort of hardware than
I do and it definitely seems reasonable - if anything it might be more flexible
than it needs to be.
I've highlighted a few small things in the patches. With those fixed I'm happy
to apply the remainder of this series unless someone shouts in the meantime.
There has been plenty of time for review, so fingers crossed that anyone
who hasn't commented, but cares, is happy with how you have done it.
So, lucky v17! Persistence pays off in the end.
Thanks,
Jonathan
>
> Jonathan
>
> >
> > William Breathitt Gray (14):
> > counter: stm32-lptimer-cnt: Provide defines for clock polarities
> > counter: stm32-timer-cnt: Provide defines for slave mode selection
> > counter: Internalize sysfs interface code
> > counter: Update counter.h comments to reflect sysfs internalization
> > docs: counter: Update to reflect sysfs internalization
> > counter: Move counter enums to uapi header
> > counter: Add character device interface
> > docs: counter: Document character device interface
> > tools/counter: Create Counter tools
> > counter: Implement signalZ_action_component_id sysfs attribute
> > counter: Implement *_component_id sysfs attributes
> > counter: Implement events_queue_size sysfs attribute
> > counter: 104-quad-8: Replace mutex with spinlock
> > counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
> >
> > Documentation/ABI/testing/sysfs-bus-counter | 38 +-
> > Documentation/driver-api/generic-counter.rst | 358 +++-
> > .../userspace-api/ioctl/ioctl-number.rst | 1 +
> > MAINTAINERS | 3 +-
> > drivers/counter/104-quad-8.c | 699 ++++----
> > drivers/counter/Kconfig | 6 +-
> > drivers/counter/Makefile | 1 +
> > drivers/counter/counter-chrdev.c | 553 ++++++
> > drivers/counter/counter-chrdev.h | 14 +
> > drivers/counter/counter-core.c | 191 +++
> > drivers/counter/counter-sysfs.c | 960 +++++++++++
> > drivers/counter/counter-sysfs.h | 13 +
> > drivers/counter/counter.c | 1496 -----------------
> > drivers/counter/ftm-quaddec.c | 60 +-
> > drivers/counter/intel-qep.c | 144 +-
> > drivers/counter/interrupt-cnt.c | 62 +-
> > drivers/counter/microchip-tcb-capture.c | 91 +-
> > drivers/counter/stm32-lptimer-cnt.c | 212 ++-
> > drivers/counter/stm32-timer-cnt.c | 195 +--
> > drivers/counter/ti-eqep.c | 180 +-
> > include/linux/counter.h | 715 ++++----
> > include/linux/counter_enum.h | 45 -
> > include/linux/mfd/stm32-lptimer.h | 5 +
> > include/linux/mfd/stm32-timers.h | 4 +
> > include/uapi/linux/counter.h | 154 ++
> > tools/Makefile | 13 +-
> > tools/counter/Build | 1 +
> > tools/counter/Makefile | 53 +
> > tools/counter/counter_example.c | 93 +
> > 29 files changed, 3569 insertions(+), 2791 deletions(-)
> > create mode 100644 drivers/counter/counter-chrdev.c
> > create mode 100644 drivers/counter/counter-chrdev.h
> > create mode 100644 drivers/counter/counter-core.c
> > create mode 100644 drivers/counter/counter-sysfs.c
> > create mode 100644 drivers/counter/counter-sysfs.h
> > delete mode 100644 drivers/counter/counter.c
> > delete mode 100644 include/linux/counter_enum.h
> > create mode 100644 include/uapi/linux/counter.h
> > create mode 100644 tools/counter/Build
> > create mode 100644 tools/counter/Makefile
> > create mode 100644 tools/counter/counter_example.c
> >
> >
> > base-commit: 5ffeb17c0d3dd44704b4aee83e297ec07666e4d6
>
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-09-12 16:18 ` Jonathan Cameron
@ 2021-09-20 10:09 ` William Breathitt Gray
2021-09-26 15:15 ` Jonathan Cameron
0 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-09-20 10:09 UTC (permalink / raw)
To: Jonathan Cameron
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
[-- Attachment #1: Type: text/plain, Size: 34337 bytes --]
On Sun, Sep 12, 2021 at 05:18:42PM +0100, Jonathan Cameron wrote:
> On Fri, 27 Aug 2021 12:47:51 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>
> > This patch introduces a character device interface for the Counter
> > subsystem. Device data is exposed through standard character device read
> > operations. Device data is gathered when a Counter event is pushed by
> > the respective Counter device driver. Configuration is handled via ioctl
> > operations on the respective Counter character device node.
> >
> > Cc: David Lechner <david@lechnology.com>
> > Cc: Gwendal Grignou <gwendal@chromium.org>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
>
> Hi William,
>
> Why the bit based lock? It feels like a mutex_trylock() type approach or
> spinlock_trylock() would be a more common solution to this problem.
> There is precedence for doing what you have here though so I'm not that
> worried about it.
Hi Jonathan,
We originally used a mutex for this, but Jarkko discovered that this
produced a warning because chrdev_lock would be held when returning to
user space:
https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
Following David Lechner's suggestion, I decided to reimplement
chrdev_lock as a bitmap using an atomic flag.
> There are a few more things inline.
>
> I've now been through this patch with as fine toothed comb as I'm likely to
> do so. Hence I won't do another review unless there are substantial changes.
> I nearly applied it as it stands, but given we aren't in a rush (merge window
> open), it's worth just a little more time to tidy up loose ends.
>
> Jonathan
Responses follow below.
> > ---
> > drivers/counter/Makefile | 2 +-
> > drivers/counter/counter-chrdev.c | 553 +++++++++++++++++++++++++++++++
> > drivers/counter/counter-chrdev.h | 14 +
> > drivers/counter/counter-core.c | 60 +++-
> > include/linux/counter.h | 51 +++
> > include/uapi/linux/counter.h | 98 ++++++
> > 6 files changed, 770 insertions(+), 8 deletions(-)
> > create mode 100644 drivers/counter/counter-chrdev.c
> > create mode 100644 drivers/counter/counter-chrdev.h
> >
> > diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> > index 1ab7e087fdc2..8fde6c100ebc 100644
> > --- a/drivers/counter/Makefile
> > +++ b/drivers/counter/Makefile
> > @@ -4,7 +4,7 @@
> > #
> >
> > obj-$(CONFIG_COUNTER) += counter.o
> > -counter-y := counter-core.o counter-sysfs.o
> > +counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
> >
> > obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
> > obj-$(CONFIG_INTERRUPT_CNT) += interrupt-cnt.o
> > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > new file mode 100644
> > index 000000000000..30659b67d8f3
> > --- /dev/null
> > +++ b/drivers/counter/counter-chrdev.c
> > @@ -0,0 +1,553 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Generic Counter character device interface
> > + * Copyright (C) 2020 William Breathitt Gray
> > + */
> > +#include <linux/bitops.h>
> > +#include <linux/cdev.h>
> > +#include <linux/counter.h>
> > +#include <linux/err.h>
> > +#include <linux/errno.h>
> > +#include <linux/export.h>
> > +#include <linux/fs.h>
> > +#include <linux/kfifo.h>
> > +#include <linux/list.h>
> > +#include <linux/mutex.h>
> > +#include <linux/nospec.h>
> > +#include <linux/poll.h>
> > +#include <linux/slab.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/timekeeping.h>
> > +#include <linux/types.h>
> > +#include <linux/uaccess.h>
> > +#include <linux/wait.h>
> > +
> > +#include "counter-chrdev.h"
> > +
> > +struct counter_comp_node {
> > + struct list_head l;
> > + struct counter_component component;
> > + struct counter_comp comp;
> > + void *parent;
> > +};
> > +
> > +static ssize_t counter_chrdev_read(struct file *filp, char __user *buf,
> > + size_t len, loff_t *f_ps)
> > +{
> > + struct counter_device *const counter = filp->private_data;
> > + int err;
> > + unsigned int copied;
> > +
> > + if (!counter->ops)
> > + return -ENODEV;
> > +
> > + if (len < sizeof(struct counter_event))
> > + return -EINVAL;
> > +
> > + do {
> > + if (kfifo_is_empty(&counter->events)) {
> > + if (filp->f_flags & O_NONBLOCK)
> > + return -EAGAIN;
> > +
> > + err = wait_event_interruptible(counter->events_wait,
> > + !kfifo_is_empty(&counter->events) ||
> > + !counter->ops);
> > + if (err < 0)
> > + return err;
> > + if (!counter->ops)
> > + return -ENODEV;
> > + }
> > +
> > + if (mutex_lock_interruptible(&counter->events_lock))
> > + return -ERESTARTSYS;
> > + err = kfifo_to_user(&counter->events, buf, len, &copied);
> > + mutex_unlock(&counter->events_lock);
> > + if (err < 0)
> > + return err;
> > + } while (!copied);
> > +
> > + return copied;
> > +}
> > +
> > +static __poll_t counter_chrdev_poll(struct file *filp,
> > + struct poll_table_struct *pollt)
> > +{
> > + struct counter_device *const counter = filp->private_data;
> > + __poll_t events = 0;
> > +
> > + if (!counter->ops)
> > + return events;
> > +
> > + poll_wait(filp, &counter->events_wait, pollt);
> > +
> > + if (!kfifo_is_empty(&counter->events))
> > + events = EPOLLIN | EPOLLRDNORM;
> > +
> > + return events;
> > +}
> > +
> > +static void counter_events_list_free(struct list_head *const events_list)
> > +{
> > + struct counter_event_node *p, *n;
> > + struct counter_comp_node *q, *o;
> > +
> > + list_for_each_entry_safe(p, n, events_list, l) {
> > + /* Free associated component nodes */
> > + list_for_each_entry_safe(q, o, &p->comp_list, l) {
> > + list_del(&q->l);
> > + kfree(q);
> > + }
> > +
> > + /* Free event node */
> > + list_del(&p->l);
> > + kfree(p);
> > + }
> > +}
> > +
> > +static int counter_set_event_node(struct counter_device *const counter,
> > + struct counter_watch *const watch,
> > + const struct counter_comp_node *const cfg)
> > +{
> > + struct counter_event_node *event_node;
> > + int err = 0;
> > + struct counter_comp_node *comp_node;
> > +
> > + /* Search for event in the list */
> > + list_for_each_entry(event_node, &counter->next_events_list, l)
> > + if (event_node->event == watch->event &&
> > + event_node->channel == watch->channel)
> > + break;
> > +
> > + /* If event is not already in the list */
> > + if (&event_node->l == &counter->next_events_list) {
> > + /* Allocate new event node */
> > + event_node = kmalloc(sizeof(*event_node), GFP_KERNEL);
> > + if (!event_node)
> > + return -ENOMEM;
> > +
> > + /* Configure event node and add to the list */
> > + event_node->event = watch->event;
> > + event_node->channel = watch->channel;
> > + INIT_LIST_HEAD(&event_node->comp_list);
> > + list_add(&event_node->l, &counter->next_events_list);
> > + }
> > +
> > + /* Check if component watch has already been set before */
> > + list_for_each_entry(comp_node, &event_node->comp_list, l)
> > + if (comp_node->parent == cfg->parent &&
> > + comp_node->comp.count_u8_read == cfg->comp.count_u8_read) {
> > + err = -EINVAL;
> > + goto exit_free_event_node;
> > + }
> > +
> > + /* Allocate component node */
> > + comp_node = kmalloc(sizeof(*comp_node), GFP_KERNEL);
> > + if (!comp_node) {
> > + err = -ENOMEM;
> > + goto exit_free_event_node;
> > + }
> > + *comp_node = *cfg;
> > +
> > + /* Add component node to event node */
> > + list_add_tail(&comp_node->l, &event_node->comp_list);
> > +
> > +exit_free_event_node:
> > + /* Free event node if no one else is watching */
> > + if (list_empty(&event_node->comp_list)) {
> > + list_del(&event_node->l);
> > + kfree(event_node);
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static int counter_enable_events(struct counter_device *const counter)
> > +{
> > + unsigned long flags;
> > + int err = 0;
> > +
> > + mutex_lock(&counter->n_events_list_lock);
> > + spin_lock_irqsave(&counter->events_list_lock, flags);
> > +
> > + counter_events_list_free(&counter->events_list);
> > + list_replace_init(&counter->next_events_list,
> > + &counter->events_list);
> > +
> > + if (counter->ops->events_configure)
> > + err = counter->ops->events_configure(counter);
> > +
> > + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> > + mutex_unlock(&counter->n_events_list_lock);
> > +
> > + return err;
> > +}
> > +
> > +static int counter_disable_events(struct counter_device *const counter)
> > +{
> > + unsigned long flags;
> > + int err = 0;
> > +
> > + spin_lock_irqsave(&counter->events_list_lock, flags);
> > +
> > + counter_events_list_free(&counter->events_list);
> > +
> > + if (counter->ops->events_configure)
> > + err = counter->ops->events_configure(counter);
> > +
> > + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> > +
> > + mutex_lock(&counter->n_events_list_lock);
> > +
> > + counter_events_list_free(&counter->next_events_list);
> > +
> > + mutex_unlock(&counter->n_events_list_lock);
> > +
> > + return err;
> > +}
> > +
> > +static int counter_add_watch(struct counter_device *const counter,
> > + const unsigned long arg)
> > +{
> > + void __user *const uwatch = (void __user *)arg;
> > + struct counter_watch watch;
> > + struct counter_comp_node comp_node = {};
> > + size_t parent, id;
> > + struct counter_comp *ext;
> > + size_t num_ext;
> > + int err = 0;
> > +
> > + if (copy_from_user(&watch, uwatch, sizeof(watch)))
> > + return -EFAULT;
> > +
> > + if (watch.component.type == COUNTER_COMPONENT_NONE)
> > + goto no_component;
> > +
> > + parent = watch.component.parent;
> > +
> > + /* Configure parent component info for comp node */
> > + switch (watch.component.scope) {
> > + case COUNTER_SCOPE_DEVICE:
> > + ext = counter->ext;
> > + num_ext = counter->num_ext;
> > + break;
> > + case COUNTER_SCOPE_SIGNAL:
> > + if (parent >= counter->num_signals)
> > + return -EINVAL;
> > + parent = array_index_nospec(parent, counter->num_signals);
> > +
> > + comp_node.parent = counter->signals + parent;
> > +
> > + ext = counter->signals[parent].ext;
> > + num_ext = counter->signals[parent].num_ext;
> > + break;
> > + case COUNTER_SCOPE_COUNT:
> > + if (parent >= counter->num_counts)
> > + return -EINVAL;
> > + parent = array_index_nospec(parent, counter->num_counts);
> > +
> > + comp_node.parent = counter->counts + parent;
> > +
> > + ext = counter->counts[parent].ext;
> > + num_ext = counter->counts[parent].num_ext;
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + id = watch.component.id;
> > +
> > + /* Configure component info for comp node */
> > + switch (watch.component.type) {
> > + case COUNTER_COMPONENT_SIGNAL:
> > + if (watch.component.scope != COUNTER_SCOPE_SIGNAL)
> > + return -EINVAL;
> > +
> > + comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL;
> > + comp_node.comp.signal_u32_read = counter->ops->signal_read;
> > + break;
> > + case COUNTER_COMPONENT_COUNT:
> > + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> > + return -EINVAL;
> > +
> > + comp_node.comp.type = COUNTER_COMP_U64;
> > + comp_node.comp.count_u64_read = counter->ops->count_read;
> > + break;
> > + case COUNTER_COMPONENT_FUNCTION:
> > + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> > + return -EINVAL;
> > +
> > + comp_node.comp.type = COUNTER_COMP_FUNCTION;
> > + comp_node.comp.count_u32_read = counter->ops->function_read;
> > + break;
> > + case COUNTER_COMPONENT_SYNAPSE_ACTION:
> > + if (watch.component.scope != COUNTER_SCOPE_COUNT)
> > + return -EINVAL;
> > + if (id >= counter->counts[parent].num_synapses)
> > + return -EINVAL;
> > + id = array_index_nospec(id, counter->counts[parent].num_synapses);
> > +
> > + comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION;
> > + comp_node.comp.action_read = counter->ops->action_read;
> > + comp_node.comp.priv = counter->counts[parent].synapses + id;
> > + break;
> > + case COUNTER_COMPONENT_EXTENSION:
> > + if (id >= num_ext)
> > + return -EINVAL;
> > + id = array_index_nospec(id, num_ext);
> > +
> > + comp_node.comp = ext[id];
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > + /* Check if any read callback is set; this is part of a union */
> > + if (!comp_node.comp.count_u8_read)
>
> This isn't valid for C. The compiler is allowed to treat the elements
> of a union as not being in the same memory etc unless they are of the same
> type (which isn't true here - I think anyway)...
>
> So whilst it seems silly you need to check all the callbacks in this if
> statement. It will 'almost' always work as you have it, but it's possible
> some future optimisation by the compiler will mean that u8_read would be
> set by this point, but it delayed setting e.g. u32_read until after
> this check.
Ack, I'll recreate a couple macros to handle these checks.
> > + return -EOPNOTSUPP;
> > +
> > +no_component:
> > + mutex_lock(&counter->n_events_list_lock);
> > +
> > + if (counter->ops->watch_validate) {
> > + err = counter->ops->watch_validate(counter, &watch);
> > + if (err < 0)
> > + goto err_exit;
> > + }
> > +
> > + comp_node.component = watch.component;
> > +
> > + err = counter_set_event_node(counter, &watch, &comp_node);
> > +
> > +err_exit:
> > + mutex_unlock(&counter->n_events_list_lock);
> > +
> > + return err;
> > +}
> > +
> > +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd,
> > + unsigned long arg)
> > +{
> > + struct counter_device *const counter = filp->private_data;
> > + int ret = -ENODEV;
> > +
> > + mutex_lock(&counter->ops_exist_lock);
> > +
> > + if (!counter->ops)
> > + goto out_unlock;
> > +
> > + switch (cmd) {
> > + case COUNTER_ADD_WATCH_IOCTL:
> > + ret = counter_add_watch(counter, arg);
> > + break;
> > + case COUNTER_ENABLE_EVENTS_IOCTL:
> > + ret = counter_enable_events(counter);
> > + break;
> > + case COUNTER_DISABLE_EVENTS_IOCTL:
> > + ret = counter_disable_events(counter);
> > + break;
> > + default:
> > + ret = -ENOIOCTLCMD;
> > + break;
> > + }
> > +
> > +out_unlock:
> > + mutex_unlock(&counter->ops_exist_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static int counter_chrdev_open(struct inode *inode, struct file *filp)
> > +{
> > + struct counter_device *const counter = container_of(inode->i_cdev,
> > + typeof(*counter),
> > + chrdev);
> > +
> > + if (test_and_set_bit_lock(0, counter->chrdev_lock))
> > + return -EBUSY;
> > +
> > + get_device(&counter->dev);
> > + filp->private_data = counter;
> > +
> > + return nonseekable_open(inode, filp);
> > +}
> > +
> > +static int counter_chrdev_release(struct inode *inode, struct file *filp)
> > +{
> > + struct counter_device *const counter = filp->private_data;
> > + int ret = 0;
> > +
> > + mutex_lock(&counter->ops_exist_lock);
> > +
> > + if (!counter->ops) {
>
> This needs a comment to explain how you would get here and
> why these two lists need cleaning up here if we do.
>
> Superficially it feels to me like you could just add a counter->ops check in
> counter_disable_events() and then call that directly. I'm guessing
> I am missing a deadlock or similar however.
I don't believe there is a risk of a deadlock, I just felt this
conditional check isn't really related to the counter_disable_events()
path so I kept it seperate; the events lists are freed in
counter_disable_events() but that's incidental rather than the purpose
of the function. My reasoning for the separation is that there are two
scenarios where counter_chrdev_release is called: the first is when a
user closes the chrdev, while the second is when the Counter driver is
removed.
For the first scenario, the counter_disable_events() function is called
to stop events from firing off when noone has the chrdev open. In the
second scenario, we are not interested in disabling events, we know
we're no longer going to be interacting with this device again so we
want to free any held memory.
I want to keep the intention of these code paths clear because the
distinction is important if we start managing additional memory in the
future (i.e. memory unrelated to the events list that would not be freed
in counter_disable_events()), so I'll add a comment explaining what's
happening in this path. Alternatively, I could define a
counter_chrdev_free() function and toss those list free calls into
there, but perhaps that would be overkill right now for just two calls.
> > + counter_events_list_free(&counter->events_list);
> > + counter_events_list_free(&counter->next_events_list);
> > + ret = -ENODEV;
> > + goto out_unlock;
> > + }
> > +
> > + ret = counter_disable_events(counter);
> > + if (ret < 0) {
> > + mutex_unlock(&counter->ops_exist_lock);
> > + return ret;
> > + }
> > +
> > +out_unlock:
> > + mutex_unlock(&counter->ops_exist_lock);
> > +
> > + put_device(&counter->dev);
> > + clear_bit_unlock(0, counter->chrdev_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static const struct file_operations counter_fops = {
> > + .owner = THIS_MODULE,
> > + .llseek = no_llseek,
> > + .read = counter_chrdev_read,
> > + .poll = counter_chrdev_poll,
> > + .unlocked_ioctl = counter_chrdev_ioctl,
> > + .open = counter_chrdev_open,
> > + .release = counter_chrdev_release,
> > +};
> > +
> > +int counter_chrdev_add(struct counter_device *const counter)
>
> To think about: This isn't doing the add. So would counter_chrdev_init() be more
> appropriate? The fact it can fail due to the kfifo_alloc makes that
> naming less than ideal though.
I've been using the "add" here to refer to adding the chrdev to the
counter_device structure rather than to the rest of the system. I used a
similar naming convention for the counter-sysfs.c file so I think
"counter_chrdev_add" here should be all right and is consistent with the
existing "counter_sysfs_add" function.
> > +{
> > + /* Initialize Counter events lists */
> > + INIT_LIST_HEAD(&counter->events_list);
> > + INIT_LIST_HEAD(&counter->next_events_list);
> > + spin_lock_init(&counter->events_list_lock);
> > + mutex_init(&counter->n_events_list_lock);
> > + init_waitqueue_head(&counter->events_wait);
> > + mutex_init(&counter->events_lock);
> > +
> > + /* Initialize character device */
> > + clear_bit(0, counter->chrdev_lock);
> > + cdev_init(&counter->chrdev, &counter_fops);
> > +
> > + /* Allocate Counter events queue */
> > + return kfifo_alloc(&counter->events, 64, GFP_KERNEL);
> > +}
> > +
> > +void counter_chrdev_remove(struct counter_device *const counter)
> > +{
> > + kfifo_free(&counter->events);
> > +}
> > +
> > +static int counter_get_data(struct counter_device *const counter,
> > + const struct counter_comp_node *const comp_node,
> > + u64 *const value)
> > +{
> > + const struct counter_comp *const comp = &comp_node->comp;
> > + void *const parent = comp_node->parent;
> > + u8 value_u8 = 0;
> > + u32 value_u32 = 0;
> > + int ret;
> > +
> > + if (comp_node->component.type == COUNTER_COMPONENT_NONE)
> > + return 0;
> > +
> > + switch (comp->type) {
> > + case COUNTER_COMP_U8:
> > + case COUNTER_COMP_BOOL:
> > + switch (comp_node->component.scope) {
> > + case COUNTER_SCOPE_DEVICE:
> > + ret = comp->device_u8_read(counter, &value_u8);
> > + break;
> > + case COUNTER_SCOPE_SIGNAL:
> > + ret = comp->signal_u8_read(counter, parent, &value_u8);
> > + break;
> > + case COUNTER_SCOPE_COUNT:
> > + ret = comp->count_u8_read(counter, parent, &value_u8);
> > + break;
> > + }
> > + *value = value_u8;
> > + return ret;
> > + case COUNTER_COMP_SIGNAL_LEVEL:
> > + case COUNTER_COMP_FUNCTION:
> > + case COUNTER_COMP_ENUM:
> > + case COUNTER_COMP_COUNT_DIRECTION:
> > + case COUNTER_COMP_COUNT_MODE:
> > + switch (comp_node->component.scope) {
> > + case COUNTER_SCOPE_DEVICE:
> > + ret = comp->device_u32_read(counter, &value_u32);
> > + break;
> > + case COUNTER_SCOPE_SIGNAL:
> > + ret = comp->signal_u32_read(counter, parent,
> > + &value_u32);
> > + break;
> > + case COUNTER_SCOPE_COUNT:
> > + ret = comp->count_u32_read(counter, parent, &value_u32);
> > + break;
> > + }
> > + *value = value_u32;
> > + return ret;
> > + case COUNTER_COMP_U64:
> > + switch (comp_node->component.scope) {
> > + case COUNTER_SCOPE_DEVICE:
> > + return comp->device_u64_read(counter, value);
> > + case COUNTER_SCOPE_SIGNAL:
> > + return comp->signal_u64_read(counter, parent, value);
> > + case COUNTER_SCOPE_COUNT:
> > + return comp->count_u64_read(counter, parent, value);
> > + default:
> > + return -EINVAL;
> > + }
> > + case COUNTER_COMP_SYNAPSE_ACTION:
> > + ret = comp->action_read(counter, parent, comp->priv,
> > + &value_u32);
> > + *value = value_u32;
> > + return ret;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +/**
> > + * counter_push_event - queue event for userspace reading
> > + * @counter: pointer to Counter structure
> > + * @event: triggered event
> > + * @channel: event channel
> > + *
> > + * Note: If no one is watching for the respective event, it is silently
> > + * discarded.
> > + */
> > +void counter_push_event(struct counter_device *const counter, const u8 event,
> > + const u8 channel)
> > +{
> > + struct counter_event ev;
> > + unsigned int copied = 0;
> > + unsigned long flags;
> > + struct counter_event_node *event_node;
> > + struct counter_comp_node *comp_node;
> > +
> > + ev.timestamp = ktime_get_ns();
> > + ev.watch.event = event;
> > + ev.watch.channel = channel;
> > +
> > + /* Could be in an interrupt context, so use a spin lock */
> > + spin_lock_irqsave(&counter->events_list_lock, flags);
> > +
> > + /* Search for event in the list */
>
> Worth keeping in mind that searching a list is not exactly a scalable
> solution even if it's fine for now.
>
> > + list_for_each_entry(event_node, &counter->events_list, l)
> > + if (event_node->event == event &&
> > + event_node->channel == channel)
> > + break;
> > +
> > + /* If event is not in the list */
> > + if (&event_node->l == &counter->events_list)
> > + goto exit_early;
> > +
> > + /* Read and queue relevant comp for userspace */
> > + list_for_each_entry(comp_node, &event_node->comp_list, l) {
> > + ev.watch.component = comp_node->component;
> > + ev.status = -counter_get_data(counter, comp_node, &ev.value);
> > +
> > + copied += kfifo_in(&counter->events, &ev, 1);
>
> I had a short debate with myself on whether this or kfifo_put() was more appropriate
> (as fixed record length). I think this particular case they end up the same anyway
> so it doesn't matter (nothing to do here!)
>
> > + }
> > +
> > +exit_early:
> > + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> > +
> > + if (copied)
> > + wake_up_poll(&counter->events_wait, EPOLLIN);
> > +}
> > +EXPORT_SYMBOL_GPL(counter_push_event);
> > diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
> > new file mode 100644
> > index 000000000000..5529d16703c4
> > --- /dev/null
> > +++ b/drivers/counter/counter-chrdev.h
> > @@ -0,0 +1,14 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Counter character device interface
> > + * Copyright (C) 2020 William Breathitt Gray
> > + */
> > +#ifndef _COUNTER_CHRDEV_H_
> > +#define _COUNTER_CHRDEV_H_
> > +
> > +#include <linux/counter.h>
> > +
> > +int counter_chrdev_add(struct counter_device *const counter);
> > +void counter_chrdev_remove(struct counter_device *const counter);
> > +
> > +#endif /* _COUNTER_CHRDEV_H_ */
> > diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> > index 3cda2c47bacb..28dc1ff63c94 100644
> > --- a/drivers/counter/counter-core.c
> > +++ b/drivers/counter/counter-core.c
> > @@ -3,14 +3,22 @@
> > * Generic Counter interface
> > * Copyright (C) 2020 William Breathitt Gray
> > */
> > +#include <linux/cdev.h>
> > #include <linux/counter.h>
> > #include <linux/device.h>
> > +#include <linux/device/bus.h>
> > #include <linux/export.h>
> > +#include <linux/fs.h>
> > #include <linux/gfp.h>
> > #include <linux/idr.h>
> > #include <linux/init.h>
> > +#include <linux/kdev_t.h>
> > #include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/types.h>
> > +#include <linux/wait.h>
> >
> > +#include "counter-chrdev.h"
> > #include "counter-sysfs.h"
> >
> > /* Provides a unique ID for each counter device */
> > @@ -18,6 +26,9 @@ static DEFINE_IDA(counter_ida);
> >
> > static void counter_device_release(struct device *dev)
> > {
> > + struct counter_device *const counter = dev_get_drvdata(dev);
> > +
> > + counter_chrdev_remove(counter);
> > ida_free(&counter_ida, dev->id);
> > }
> >
> > @@ -31,6 +42,8 @@ static struct bus_type counter_bus_type = {
> > .dev_name = "counter",
> > };
> >
> > +static dev_t counter_devt;
> > +
> > /**
> > * counter_register - register Counter to the system
> > * @counter: pointer to Counter to register
> > @@ -53,10 +66,13 @@ int counter_register(struct counter_device *const counter)
> > if (id < 0)
> > return id;
> >
> > + mutex_init(&counter->ops_exist_lock);
> > +
> > /* Configure device structure for Counter */
> > dev->id = id;
> > dev->type = &counter_device_type;
> > dev->bus = &counter_bus_type;
> > + dev->devt = MKDEV(MAJOR(counter_devt), id);
> > if (counter->parent) {
> > dev->parent = counter->parent;
> > dev->of_node = counter->parent->of_node;
> > @@ -64,18 +80,22 @@ int counter_register(struct counter_device *const counter)
> > device_initialize(dev);
> > dev_set_drvdata(dev, counter);
> >
> > - /* Add Counter sysfs attributes */
> > - err = counter_sysfs_add(counter);
> > + err = counter_chrdev_add(counter);
> > if (err < 0)
> > goto err_free_id;
> >
> > - /* Add device to system */
> > - err = device_add(dev);
> > + err = counter_sysfs_add(counter);
> > if (err < 0)
> > - goto err_free_id;
> > + goto err_remove_chrdev;
> > +
> > + err = cdev_device_add(&counter->chrdev, dev);
> > + if (err < 0)
> > + goto err_remove_chrdev;
> >
> > return 0;
> >
> > +err_remove_chrdev:
> > + counter_chrdev_remove(counter);
>
> Totally trivial, but the sysfs cleanup is managed by devm_ whilst this counter_chrdev_remove()
> is manual. That leaves us in a case where the unwind order is subtly different from the
> reverse of the setup order. Is there any reason to not do the sysfs part of register first
> and hence have the ordering match?
I think in an earlier revision of this patchset counter-chrdev had a
dependency on counter-sysfs, but that's no longer the case so we should
be able to reorder these calls so that the unwind order matches.
> > err_free_id:
> > put_device(dev);
> > return err;
> > @@ -93,7 +113,16 @@ void counter_unregister(struct counter_device *const counter)
> > if (!counter)
> > return;
> >
> > - device_unregister(&counter->dev);
> > + cdev_device_del(&counter->chrdev, &counter->dev);
> > +
> > + mutex_lock(&counter->ops_exist_lock);
> > +
> > + counter->ops = NULL;
> > + wake_up(&counter->events_wait);
> > +
> > + mutex_unlock(&counter->ops_exist_lock);
> > +
> > + put_device(&counter->dev);
> > }
> > EXPORT_SYMBOL_GPL(counter_unregister);
> >
> > @@ -127,13 +156,30 @@ int devm_counter_register(struct device *dev,
> > }
> > EXPORT_SYMBOL_GPL(devm_counter_register);
> >
> > +#define COUNTER_DEV_MAX 256
> > +
> > static int __init counter_init(void)
> > {
> > - return bus_register(&counter_bus_type);
> > + int err;
> > +
> > + err = bus_register(&counter_bus_type);
>
> Hmm. This isn't ideal in IIO either, but logically bus_register() is the part that
> exposes the infrastructure for other drivers to attach to so should be last thing
> in init. However, I'm fairly sure the dependency handing will ensure this init()
> is finished before it tries to register any counter drivers. Hence we are fine
> anyway.
>
> So in conclusion - nothing needs changing here...
Ack. Given that things work all right rigth now, I'll revisit this again
in the future as a general cleanup improvment after this patchset is
merged so that we don't risk complicating the Counter character device
functionality introduction any further.
> > + if (err < 0)
> > + return err;
> > +
> > + err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
> > + if (err < 0)
> > + goto err_unregister_bus;
> > +
> > + return 0;
> > +
> > +err_unregister_bus:
> > + bus_unregister(&counter_bus_type);
> > + return err;
> > }
> >
> > static void __exit counter_exit(void)
> > {
> > + unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
> > bus_unregister(&counter_bus_type);
> > }
> >
> > diff --git a/include/linux/counter.h b/include/linux/counter.h
> > index 7c9f7e23953a..9c9984655f8c 100644
> > --- a/include/linux/counter.h
> > +++ b/include/linux/counter.h
> > @@ -6,9 +6,14 @@
> > #ifndef _COUNTER_H_
> > #define _COUNTER_H_
> >
> > +#include <linux/cdev.h>
> > #include <linux/device.h>
> > #include <linux/kernel.h>
> > +#include <linux/kfifo.h>
> > +#include <linux/mutex.h>
> > +#include <linux/spinlock_types.h>
> > #include <linux/types.h>
> > +#include <linux/wait.h>
> > #include <uapi/linux/counter.h>
> >
> > struct counter_device;
> > @@ -199,6 +204,20 @@ struct counter_count {
> > size_t num_ext;
> > };
> >
> > +/**
> > + * struct counter_event_node - Counter Event node
> > + * @l: list of current watching Counter events
> > + * @event: event that triggers
> > + * @channel: event channel
> > + * @comp_list: list of components to watch when event triggers
> > + */
> > +struct counter_event_node {
> > + struct list_head l;
> > + u8 event;
> > + u8 channel;
> > + struct list_head comp_list;
> > +};
> > +
> > /**
> > * struct counter_ops - Callbacks from driver
> > * @signal_read: optional read callback for Signals. The read level of
> > @@ -222,6 +241,13 @@ struct counter_count {
> > * @action_write: optional write callback for Synapse action modes. The
> > * action mode to write for the respective Synapse is
> > * passed in via the action parameter.
> > + * @events_configure: optional write callback to configure events. The list of
> > + * struct counter_event_node may be accessed via the
> > + * events_list member of the counter parameter.
> > + * @watch_validate: optional callback to validate a watch. The Counter
> > + * component watch configuration is passed in via the watch
> > + * parameter. A return value of 0 indicates a valid Counter
> > + * component watch configuration.
> > */
> > struct counter_ops {
> > int (*signal_read)(struct counter_device *counter,
> > @@ -245,6 +271,9 @@ struct counter_ops {
> > struct counter_count *count,
> > struct counter_synapse *synapse,
> > enum counter_synapse_action action);
> > + int (*events_configure)(struct counter_device *counter);
> > + int (*watch_validate)(struct counter_device *counter,
> > + const struct counter_watch *watch);
> > };
> >
> > /**
> > @@ -260,6 +289,16 @@ struct counter_ops {
> > * @num_ext: number of Counter device extensions specified in @ext
> > * @priv: optional private data supplied by driver
> > * @dev: internal device structure
> > + * @chrdev: internal character device structure
> > + * @events_list: list of current watching Counter events
> > + * @events_list_lock: lock to protect Counter events list operations
> > + * @next_events_list: list of next watching Counter events
> > + * @n_events_list_lock: lock to protect Counter next events list operations
> > + * @events: queue of detected Counter events
> > + * @events_wait: wait queue to allow blocking reads of Counter events
> > + * @events_lock: lock to protect Counter events queue read operations
> > + * @chrdev_lock: lock to limit chrdev to a single open at a time
> > + * @ops_exist_lock: lock to prevent use during removal
> > */
> > struct counter_device {
> > const char *name;
> > @@ -278,12 +317,24 @@ struct counter_device {
> > void *priv;
> >
> > struct device dev;
> > + struct cdev chrdev;
> > + struct list_head events_list;
> > + spinlock_t events_list_lock;
> > + struct list_head next_events_list;
> > + struct mutex n_events_list_lock;
> > + DECLARE_KFIFO_PTR(events, struct counter_event);
> > + wait_queue_head_t events_wait;
> > + struct mutex events_lock;
> > + DECLARE_BITMAP(chrdev_lock, 1);
>
> Why use a bitmap for this rather than any of the other lock types?
We can't use a mutex due to the problems mentioned in
https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
so I think a bitmap might be the most straightforward solution here. It
goes without saying that I'm open to any other suggestions as well if
there is a better solution for this case.
William Breathitt Gray
> > + struct mutex ops_exist_lock;
> > };
> >
> > int counter_register(struct counter_device *const counter);
> > void counter_unregister(struct counter_device *const counter);
> > int devm_counter_register(struct device *dev,
> > struct counter_device *const counter);
> > +void counter_push_event(struct counter_device *const counter, const u8 event,
> > + const u8 channel);
> >
> > #define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \
> > { \
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-09-20 10:09 ` William Breathitt Gray
@ 2021-09-26 15:15 ` Jonathan Cameron
2021-09-27 10:21 ` William Breathitt Gray
0 siblings, 1 reply; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-26 15:15 UTC (permalink / raw)
To: William Breathitt Gray
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
On Mon, 20 Sep 2021 19:09:13 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> On Sun, Sep 12, 2021 at 05:18:42PM +0100, Jonathan Cameron wrote:
> > On Fri, 27 Aug 2021 12:47:51 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >
> > > This patch introduces a character device interface for the Counter
> > > subsystem. Device data is exposed through standard character device read
> > > operations. Device data is gathered when a Counter event is pushed by
> > > the respective Counter device driver. Configuration is handled via ioctl
> > > operations on the respective Counter character device node.
> > >
> > > Cc: David Lechner <david@lechnology.com>
> > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> >
> > Hi William,
> >
> > Why the bit based lock? It feels like a mutex_trylock() type approach or
> > spinlock_trylock() would be a more common solution to this problem.
> > There is precedence for doing what you have here though so I'm not that
> > worried about it.
>
> Hi Jonathan,
>
> We originally used a mutex for this, but Jarkko discovered that this
> produced a warning because chrdev_lock would be held when returning to
> user space:
> https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
>
> Following David Lechner's suggestion, I decided to reimplement
> chrdev_lock as a bitmap using an atomic flag.
Ok. I'm not sure bit lock was quite what was intended (as there is only one of them)
but I suppose it doesn't greatly matter.
>
> > There are a few more things inline.
> >
> > I've now been through this patch with as fine toothed comb as I'm likely to
> > do so. Hence I won't do another review unless there are substantial changes.
> > I nearly applied it as it stands, but given we aren't in a rush (merge window
> > open), it's worth just a little more time to tidy up loose ends.
> >
> > Jonathan
>
> Responses follow below.
...
...
> > > +static int counter_chrdev_release(struct inode *inode, struct file *filp)
> > > +{
> > > + struct counter_device *const counter = filp->private_data;
> > > + int ret = 0;
> > > +
> > > + mutex_lock(&counter->ops_exist_lock);
> > > +
> > > + if (!counter->ops) {
> >
> > This needs a comment to explain how you would get here and
> > why these two lists need cleaning up here if we do.
> >
> > Superficially it feels to me like you could just add a counter->ops check in
> > counter_disable_events() and then call that directly. I'm guessing
> > I am missing a deadlock or similar however.
>
> I don't believe there is a risk of a deadlock, I just felt this
> conditional check isn't really related to the counter_disable_events()
> path so I kept it seperate; the events lists are freed in
> counter_disable_events() but that's incidental rather than the purpose
> of the function. My reasoning for the separation is that there are two
> scenarios where counter_chrdev_release is called: the first is when a
> user closes the chrdev, while the second is when the Counter driver is
> removed.
>
> For the first scenario, the counter_disable_events() function is called
> to stop events from firing off when noone has the chrdev open. In the
> second scenario, we are not interested in disabling events, we know
> we're no longer going to be interacting with this device again so we
> want to free any held memory.
>
> I want to keep the intention of these code paths clear because the
> distinction is important if we start managing additional memory in the
> future (i.e. memory unrelated to the events list that would not be freed
> in counter_disable_events()), so I'll add a comment explaining what's
> happening in this path. Alternatively, I could define a
> counter_chrdev_free() function and toss those list free calls into
> there, but perhaps that would be overkill right now for just two calls.
A comment would be enough for now I think.
>
> > > + counter_events_list_free(&counter->events_list);
> > > + counter_events_list_free(&counter->next_events_list);
> > > + ret = -ENODEV;
> > > + goto out_unlock;
> > > + }
> > > +
> > > + ret = counter_disable_events(counter);
> > > + if (ret < 0) {
> > > + mutex_unlock(&counter->ops_exist_lock);
> > > + return ret;
> > > + }
> > > +
> > > +out_unlock:
> > > + mutex_unlock(&counter->ops_exist_lock);
> > > +
> > > + put_device(&counter->dev);
> > > + clear_bit_unlock(0, counter->chrdev_lock);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static const struct file_operations counter_fops = {
> > > + .owner = THIS_MODULE,
> > > + .llseek = no_llseek,
> > > + .read = counter_chrdev_read,
> > > + .poll = counter_chrdev_poll,
> > > + .unlocked_ioctl = counter_chrdev_ioctl,
> > > + .open = counter_chrdev_open,
> > > + .release = counter_chrdev_release,
> > > +};
> > > +
> > > +int counter_chrdev_add(struct counter_device *const counter)
> >
> > To think about: This isn't doing the add. So would counter_chrdev_init() be more
> > appropriate? The fact it can fail due to the kfifo_alloc makes that
> > naming less than ideal though.
>
> I've been using the "add" here to refer to adding the chrdev to the
> counter_device structure rather than to the rest of the system. I used a
> similar naming convention for the counter-sysfs.c file so I think
> "counter_chrdev_add" here should be all right and is consistent with the
> existing "counter_sysfs_add" function.
Hmm. I'll go with maybe and reserve the right to say I told you so if
it ever causes problem (and I can remember this discussion which is
fairly unlikely!).
...
...
> > >
> > > /**
> > > @@ -260,6 +289,16 @@ struct counter_ops {
> > > * @num_ext: number of Counter device extensions specified in @ext
> > > * @priv: optional private data supplied by driver
> > > * @dev: internal device structure
> > > + * @chrdev: internal character device structure
> > > + * @events_list: list of current watching Counter events
> > > + * @events_list_lock: lock to protect Counter events list operations
> > > + * @next_events_list: list of next watching Counter events
> > > + * @n_events_list_lock: lock to protect Counter next events list operations
> > > + * @events: queue of detected Counter events
> > > + * @events_wait: wait queue to allow blocking reads of Counter events
> > > + * @events_lock: lock to protect Counter events queue read operations
> > > + * @chrdev_lock: lock to limit chrdev to a single open at a time
> > > + * @ops_exist_lock: lock to prevent use during removal
> > > */
> > > struct counter_device {
> > > const char *name;
> > > @@ -278,12 +317,24 @@ struct counter_device {
> > > void *priv;
> > >
> > > struct device dev;
> > > + struct cdev chrdev;
> > > + struct list_head events_list;
> > > + spinlock_t events_list_lock;
> > > + struct list_head next_events_list;
> > > + struct mutex n_events_list_lock;
> > > + DECLARE_KFIFO_PTR(events, struct counter_event);
> > > + wait_queue_head_t events_wait;
> > > + struct mutex events_lock;
> > > + DECLARE_BITMAP(chrdev_lock, 1);
> >
> > Why use a bitmap for this rather than any of the other lock types?
>
> We can't use a mutex due to the problems mentioned in
> https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
> so I think a bitmap might be the most straightforward solution here. It
> goes without saying that I'm open to any other suggestions as well if
> there is a better solution for this case.
Add a comment here so no one tries to refactor it in the future without
understanding your reasoning.
>
> William Breathitt Gray
Thanks,
Jonathan
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-09-26 15:15 ` Jonathan Cameron
@ 2021-09-27 10:21 ` William Breathitt Gray
2021-09-27 11:20 ` Jonathan Cameron
0 siblings, 1 reply; 32+ messages in thread
From: William Breathitt Gray @ 2021-09-27 10:21 UTC (permalink / raw)
To: Jonathan Cameron
Cc: linux-stm32, kernel, a.fatoum, kamel.bouhara, gwendal,
alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
[-- Attachment #1: Type: text/plain, Size: 2083 bytes --]
On Sun, Sep 26, 2021 at 04:15:42PM +0100, Jonathan Cameron wrote:
> On Mon, 20 Sep 2021 19:09:13 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>
> > On Sun, Sep 12, 2021 at 05:18:42PM +0100, Jonathan Cameron wrote:
> > > On Fri, 27 Aug 2021 12:47:51 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >
> > > > This patch introduces a character device interface for the Counter
> > > > subsystem. Device data is exposed through standard character device read
> > > > operations. Device data is gathered when a Counter event is pushed by
> > > > the respective Counter device driver. Configuration is handled via ioctl
> > > > operations on the respective Counter character device node.
> > > >
> > > > Cc: David Lechner <david@lechnology.com>
> > > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > >
> > > Hi William,
> > >
> > > Why the bit based lock? It feels like a mutex_trylock() type approach or
> > > spinlock_trylock() would be a more common solution to this problem.
> > > There is precedence for doing what you have here though so I'm not that
> > > worried about it.
> >
> > Hi Jonathan,
> >
> > We originally used a mutex for this, but Jarkko discovered that this
> > produced a warning because chrdev_lock would be held when returning to
> > user space:
> > https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
> >
> > Following David Lechner's suggestion, I decided to reimplement
> > chrdev_lock as a bitmap using an atomic flag.
>
> Ok. I'm not sure bit lock was quite what was intended (as there is only one of them)
> but I suppose it doesn't greatly matter.
It didn't cross my mind before, but would declaring chrdev_lock as an
atomic_t be a more appropriate solution here because we have only one
flag?
William Breathitt Gray
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-09-27 10:21 ` William Breathitt Gray
@ 2021-09-27 11:20 ` Jonathan Cameron
2021-09-27 11:33 ` William Breathitt Gray
0 siblings, 1 reply; 32+ messages in thread
From: Jonathan Cameron @ 2021-09-27 11:20 UTC (permalink / raw)
To: William Breathitt Gray
Cc: Jonathan Cameron, linux-stm32, kernel, a.fatoum, kamel.bouhara,
gwendal, alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
On Mon, 27 Sep 2021 19:21:17 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> On Sun, Sep 26, 2021 at 04:15:42PM +0100, Jonathan Cameron wrote:
> > On Mon, 20 Sep 2021 19:09:13 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >
> > > On Sun, Sep 12, 2021 at 05:18:42PM +0100, Jonathan Cameron wrote:
> > > > On Fri, 27 Aug 2021 12:47:51 +0900
> > > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > > >
> > > > > This patch introduces a character device interface for the Counter
> > > > > subsystem. Device data is exposed through standard character device read
> > > > > operations. Device data is gathered when a Counter event is pushed by
> > > > > the respective Counter device driver. Configuration is handled via ioctl
> > > > > operations on the respective Counter character device node.
> > > > >
> > > > > Cc: David Lechner <david@lechnology.com>
> > > > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > >
> > > > Hi William,
> > > >
> > > > Why the bit based lock? It feels like a mutex_trylock() type approach or
> > > > spinlock_trylock() would be a more common solution to this problem.
> > > > There is precedence for doing what you have here though so I'm not that
> > > > worried about it.
> > >
> > > Hi Jonathan,
> > >
> > > We originally used a mutex for this, but Jarkko discovered that this
> > > produced a warning because chrdev_lock would be held when returning to
> > > user space:
> > > https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
> > >
> > > Following David Lechner's suggestion, I decided to reimplement
> > > chrdev_lock as a bitmap using an atomic flag.
> >
> > Ok. I'm not sure bit lock was quite what was intended (as there is only one of them)
> > but I suppose it doesn't greatly matter.
>
> It didn't cross my mind before, but would declaring chrdev_lock as an
> atomic_t be a more appropriate solution here because we have only one
> flag?
>
> William Breathitt Gray
>
It would be less esoteric. This was the first time I've ever come across the bitlock stuff
whereas atomics are an every day thing.
Thanks,
Jonathan
^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v16 07/14] counter: Add character device interface
2021-09-27 11:20 ` Jonathan Cameron
@ 2021-09-27 11:33 ` William Breathitt Gray
0 siblings, 0 replies; 32+ messages in thread
From: William Breathitt Gray @ 2021-09-27 11:33 UTC (permalink / raw)
To: Jonathan Cameron
Cc: Jonathan Cameron, linux-stm32, kernel, a.fatoum, kamel.bouhara,
gwendal, alexandre.belloni, david, linux-iio, linux-kernel,
linux-arm-kernel, syednwaris, patrick.havelange, fabrice.gasnier,
mcoquelin.stm32, alexandre.torgue, o.rempel, jarkko.nikula,
Dan Carpenter
[-- Attachment #1: Type: text/plain, Size: 2770 bytes --]
On Mon, Sep 27, 2021 at 12:20:00PM +0100, Jonathan Cameron wrote:
> On Mon, 27 Sep 2021 19:21:17 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>
> > On Sun, Sep 26, 2021 at 04:15:42PM +0100, Jonathan Cameron wrote:
> > > On Mon, 20 Sep 2021 19:09:13 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >
> > > > On Sun, Sep 12, 2021 at 05:18:42PM +0100, Jonathan Cameron wrote:
> > > > > On Fri, 27 Aug 2021 12:47:51 +0900
> > > > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > > > >
> > > > > > This patch introduces a character device interface for the Counter
> > > > > > subsystem. Device data is exposed through standard character device read
> > > > > > operations. Device data is gathered when a Counter event is pushed by
> > > > > > the respective Counter device driver. Configuration is handled via ioctl
> > > > > > operations on the respective Counter character device node.
> > > > > >
> > > > > > Cc: David Lechner <david@lechnology.com>
> > > > > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > > > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > >
> > > > > Hi William,
> > > > >
> > > > > Why the bit based lock? It feels like a mutex_trylock() type approach or
> > > > > spinlock_trylock() would be a more common solution to this problem.
> > > > > There is precedence for doing what you have here though so I'm not that
> > > > > worried about it.
> > > >
> > > > Hi Jonathan,
> > > >
> > > > We originally used a mutex for this, but Jarkko discovered that this
> > > > produced a warning because chrdev_lock would be held when returning to
> > > > user space:
> > > > https://lore.kernel.org/linux-arm-kernel/YOq19zTsOzKA8v7c@shinobu/T/#m6072133d418d598a5f368bb942c945e46cfab9a5
> > > >
> > > > Following David Lechner's suggestion, I decided to reimplement
> > > > chrdev_lock as a bitmap using an atomic flag.
> > >
> > > Ok. I'm not sure bit lock was quite what was intended (as there is only one of them)
> > > but I suppose it doesn't greatly matter.
> >
> > It didn't cross my mind before, but would declaring chrdev_lock as an
> > atomic_t be a more appropriate solution here because we have only one
> > flag?
> >
> > William Breathitt Gray
> >
>
> It would be less esoteric. This was the first time I've ever come across the bitlock stuff
> whereas atomics are an every day thing.
>
> Thanks,
>
> Jonathan
I agree. I'll try that out then and reimplement this using
atomic_inc_and_test() instead of test_and_set_bit_lock().
William Breathitt Gray
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 32+ messages in thread
end of thread, other threads:[~2021-09-27 11:33 UTC | newest]
Thread overview: 32+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-27 3:47 [PATCH v16 00/14] Introduce the Counter character device interface William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 01/14] counter: stm32-lptimer-cnt: Provide defines for clock polarities William Breathitt Gray
2021-08-31 13:38 ` Fabrice Gasnier
2021-09-08 17:31 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 02/14] counter: stm32-timer-cnt: Provide defines for slave mode selection William Breathitt Gray
2021-08-31 13:40 ` Fabrice Gasnier
2021-09-08 17:31 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 04/14] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
2021-09-08 17:46 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 05/14] docs: counter: Update " William Breathitt Gray
2021-09-08 17:48 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 06/14] counter: Move counter enums to uapi header William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 07/14] counter: Add character device interface William Breathitt Gray
2021-09-12 16:18 ` Jonathan Cameron
2021-09-20 10:09 ` William Breathitt Gray
2021-09-26 15:15 ` Jonathan Cameron
2021-09-27 10:21 ` William Breathitt Gray
2021-09-27 11:20 ` Jonathan Cameron
2021-09-27 11:33 ` William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 08/14] docs: counter: Document " William Breathitt Gray
2021-09-12 16:18 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 09/14] tools/counter: Create Counter tools William Breathitt Gray
2021-09-12 16:26 ` Jonathan Cameron
2021-08-27 3:47 ` [PATCH v16 10/14] counter: Implement signalZ_action_component_id sysfs attribute William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 11/14] counter: Implement *_component_id sysfs attributes William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 12/14] counter: Implement events_queue_size sysfs attribute William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 13/14] counter: 104-quad-8: Replace mutex with spinlock William Breathitt Gray
2021-08-27 3:47 ` [PATCH v16 14/14] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 William Breathitt Gray
2021-08-30 17:17 ` [PATCH v16 00/14] Introduce the Counter character device interface Jonathan Cameron
2021-09-12 16:36 ` Jonathan Cameron
[not found] ` <c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com>
[not found] ` <fcff44a7-5ac2-a510-ee9b-85ef7e2e29ef@foss.st.com>
2021-08-31 14:16 ` [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs interface code William Breathitt Gray
2021-08-31 14:55 ` William Breathitt Gray
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).