[PATCH v16 0/9] Add Error Disconnect Recover (EDR) support

[PATCH v16 0/9] Add Error Disconnect Recover (EDR) support

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

This patchset adds support for following features:

1. Error Disconnect Recover (EDR) support.
2. _OSC based negotiation support for DPC.

You can find EDR spec in the following link.

https://members.pcisig.com/wg/PCI-SIG/document/12614

Changes since v15:
 * Splitted Patch # 3 in previous set into multiple patches.
 * Refactored EDR driver use pci_dev instead of dpc_dev.
 * Added some debug logs to EDR driver.
 * Used pci_aer_raw_clear_status() for clearing AER errors in EDR path.
 * Addressed other comments from Bjorn.
 * Rebased patches on top of Bjorns "PCI/DPC: Move data to struct pci_dev" patch.

Changes since v14:
 * Rebased on top of v5.6-rc1

Changes since v13:
 * Moved all EDR related code to edr.c
 * Addressed Bjorns comments.

Changes since v12:
 * Addressed Bjorns comments.
 * Added check for CONFIG_PCIE_EDR before requesting DPC control from firmware.
 * Removed ff_check parameter from AER APIs.
 * Used macros for _OST return status values in DPC driver.

Changes since v11:
 * Allowed error recovery to proceed after successful reset_link().
 * Used correct ACPI handle for sending EDR status.
 * Rebased on top of v5.5-rc5

Changes since v10:
 * Added "edr_enabled" member to dpc priv structure, which is used to cache EDR
   enabling status based on status of pcie_ports_dpc_native and FF mode.
 * Changed type of _DSM argument from Integer to Package in acpi_enable_dpc_port()
   function to fix ACPI related boot warnings.
 * Rebased on top of v5.5-rc3

Changes since v9:
 * Removed caching of pcie_aer_get_firmware_first() in dpc driver.
 * Added proper spec reference in git log for patch 5 & 7.
 * Added new function parameter "ff_check" to pci_cleanup_aer_uncorrect_error_status(),
   pci_aer_clear_fatal_status() and pci_cleanup_aer_error_status_regs() functions.
 * Rebased on top of v5.4-rc5

Changes since v8:
 * Rebased on top of v5.4-rc1

Changes since v7:
 * Updated DSM version number to match the spec.

Changes since v6:
 * Modified the order of patches to enable EDR only after all necessary support is added in kernel.
 * Addressed Bjorn comments.

Changes since v5:
 * Addressed Keith's comments.
 * Added additional check for FF mode in pci_aer_init().
 * Updated commit history of "PCI/DPC: Add support for DPC recovery on NON_FATAL errors" patch.

Changes since v4:
 * Rebased on top of v5.3-rc1
 * Fixed lock/unlock issue in edr_handle_event().
 * Merged "Update error status after reset_link()" patch into this patchset.

Changes since v3:
 * Moved EDR related ACPI functions/definitions to pci-acpi.c
 * Modified commit history in few patches to include spec reference.
 * Added support to handle DPC triggered by NON_FATAL errors.
 * Added edr_lock to protect PCI device receiving duplicate EDR notifications.
 * Addressed Bjorn comments.

Changes since v2:
 * Split EDR support patch into multiple patches.
 * Addressed Bjorn comments.

Changes since v1:
 * Rebased on top of v5.1-rc1

Kuppuswamy Sathyanarayanan (9):
  PCI/ERR: Update error status after reset_link()
  PCI/AER: Move pci_cleanup_aer_error_status_regs() declaration to pci.h
  PCI/ERR: Remove service dependency in pcie_do_recovery()
  PCI/ERR: Return status of pcie_do_recovery()
  PCI/DPC: Cache DPC capabilities in pci_init_capabilities()
  PCI/AER: Allow clearing Error Status Register in FF mode
  PCI/DPC: Export DPC error recovery functions
  PCI/DPC: Add Error Disconnect Recover (EDR) support
  PCI/ACPI: Enable EDR support

 drivers/acpi/pci_root.c   |  16 +++
 drivers/pci/pci-acpi.c    |   3 +
 drivers/pci/pci.h         |  16 ++-
 drivers/pci/pcie/Kconfig  |  10 ++
 drivers/pci/pcie/Makefile |   1 +
 drivers/pci/pcie/aer.c    |  33 +++--
 drivers/pci/pcie/dpc.c    |  46 ++++---
 drivers/pci/pcie/edr.c    | 251 ++++++++++++++++++++++++++++++++++++++
 drivers/pci/pcie/err.c    |  26 ++--
 drivers/pci/probe.c       |   1 +
 include/linux/acpi.h      |   6 +-
 include/linux/aer.h       |   5 -
 include/linux/pci-acpi.h  |   8 ++
 include/linux/pci.h       |   1 +
 14 files changed, 377 insertions(+), 46 deletions(-)
 create mode 100644 drivers/pci/pcie/edr.c

-- 
2.21.0

[PATCH v16 1/9] PCI/ERR: Update error status after reset_link()

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Commit bdb5ac85777d ("PCI/ERR: Handle fatal error recovery") uses
reset_link() to recover from fatal errors. But during fatal error
recovery, if the initial value of error status is
PCI_ERS_RESULT_DISCONNECT or PCI_ERS_RESULT_NO_AER_DRIVER then
even after successful recovery (using reset_link()) pcie_do_recovery()
will report the recovery result as failure. So update the status of
error after reset_link().

You can reproduce this issue by triggering a SW DPC using "DPC
Software Trigger" bit in "DPC Control Register". You should see recovery
failed dmesg log as below.

[  164.659982] pcieport 0000:00:16.0: DPC: containment event,
status:0x1f27 source:0x0000
[  164.659989] pcieport 0000:00:16.0: DPC: software trigger detected
[  164.659994] pci 0000:04:00.0: AER: can't recover (no error_detected
callback)
[  164.794300] pcieport 0000:00:16.0: AER: device recovery failed

Fixes: bdb5ac85777d ("PCI/ERR: Handle fatal error recovery")
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Keith Busch <keith.busch@intel.com>
---
 drivers/pci/pcie/err.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 01dfc8bb7ca0..eefefe03857a 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -208,9 +208,11 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
 	else
 		pci_walk_bus(bus, report_normal_detected, &status);
 
-	if (state == pci_channel_io_frozen &&
-	    reset_link(dev, service) != PCI_ERS_RESULT_RECOVERED)
-		goto failed;
+	if (state == pci_channel_io_frozen) {
+		status = reset_link(dev, service);
+		if (status != PCI_ERS_RESULT_RECOVERED)
+			goto failed;
+	}
 
 	if (status == PCI_ERS_RESULT_CAN_RECOVER) {
 		status = PCI_ERS_RESULT_RECOVERED;
-- 
2.21.0

[PATCH v16 2/9] PCI/AER: Move pci_cleanup_aer_error_status_regs() declaration to pci.h

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Since pci_cleanup_aer_error_status_regs() is only used within
drivers/pci/* directory move the function declaration to pci.h.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h   | 5 +++++
 include/linux/aer.h | 5 -----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6394e7746fb5..a4c360515a69 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -651,12 +651,17 @@ void pci_aer_exit(struct pci_dev *dev);
 extern const struct attribute_group aer_stats_attr_group;
 void pci_aer_clear_fatal_status(struct pci_dev *dev);
 void pci_aer_clear_device_status(struct pci_dev *dev);
+int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
 #else
 static inline void pci_no_aer(void) { }
 static inline void pci_aer_init(struct pci_dev *d) { }
 static inline void pci_aer_exit(struct pci_dev *d) { }
 static inline void pci_aer_clear_fatal_status(struct pci_dev *dev) { }
 static inline void pci_aer_clear_device_status(struct pci_dev *dev) { }
+static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
+{
+	return -EINVAL;
+}
 #endif
 
 #ifdef CONFIG_ACPI
diff --git a/include/linux/aer.h b/include/linux/aer.h
index fa19e01f418a..4e4b4960a3d8 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -45,7 +45,6 @@ struct aer_capability_regs {
 int pci_enable_pcie_error_reporting(struct pci_dev *dev);
 int pci_disable_pcie_error_reporting(struct pci_dev *dev);
 int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
-int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
 void pci_save_aer_state(struct pci_dev *dev);
 void pci_restore_aer_state(struct pci_dev *dev);
 #else
@@ -61,10 +60,6 @@ static inline int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev)
 {
 	return -EINVAL;
 }
-static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
-{
-	return -EINVAL;
-}
 static inline void pci_save_aer_state(struct pci_dev *dev) {}
 static inline void pci_restore_aer_state(struct pci_dev *dev) {}
 #endif
-- 
2.21.0

[PATCH v16 3/9] PCI/ERR: Remove service dependency in pcie_do_recovery()

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Currently we pass PCIe service type parameter to pcie_do_recovery()
function which was in-turn used by reset_link() function to identify
the underlying pci_port_service_driver and then initiate the driver
specific reset_link call. Instead of using this roundabout way, we
can just pass the driver specific reset_link callback function when
calling pcie_do_recovery() function.

This change will also enable non PCIe service driver to call
pcie_do_recovery() function. This is required for adding Error
Disconnect Recover (EDR) support.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h      |  2 +-
 drivers/pci/pcie/aer.c | 11 +++++------
 drivers/pci/pcie/dpc.c |  2 +-
 drivers/pci/pcie/err.c | 16 ++++++++--------
 4 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a4c360515a69..2962200bfe35 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -548,7 +548,7 @@ static inline int pci_dev_specific_disable_acs_redir(struct pci_dev *dev)
 
 /* PCI error reporting and recovery */
 void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
-		      u32 service);
+		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev));
 
 bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
 #ifdef CONFIG_PCIEASPM
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 4a818b07a1af..1235eca0a2e6 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -102,6 +102,7 @@ struct aer_stats {
 #define ERR_UNCOR_ID(d)			(d >> 16)
 
 static int pcie_aer_disable;
+static pci_ers_result_t aer_root_reset(struct pci_dev *dev);
 
 void pci_no_aer(void)
 {
@@ -1053,11 +1054,9 @@ static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
 					info->status);
 		pci_aer_clear_device_status(dev);
 	} else if (info->severity == AER_NONFATAL)
-		pcie_do_recovery(dev, pci_channel_io_normal,
-				 PCIE_PORT_SERVICE_AER);
+		pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
 	else if (info->severity == AER_FATAL)
-		pcie_do_recovery(dev, pci_channel_io_frozen,
-				 PCIE_PORT_SERVICE_AER);
+		pcie_do_recovery(dev, pci_channel_io_frozen, aer_root_reset);
 	pci_dev_put(dev);
 }
 
@@ -1094,10 +1093,10 @@ static void aer_recover_work_func(struct work_struct *work)
 		cper_print_aer(pdev, entry.severity, entry.regs);
 		if (entry.severity == AER_NONFATAL)
 			pcie_do_recovery(pdev, pci_channel_io_normal,
-					 PCIE_PORT_SERVICE_AER);
+					 aer_root_reset);
 		else if (entry.severity == AER_FATAL)
 			pcie_do_recovery(pdev, pci_channel_io_frozen,
-					 PCIE_PORT_SERVICE_AER);
+					 aer_root_reset);
 		pci_dev_put(pdev);
 	}
 }
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 6b116d7fdb89..114358d62ddf 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -227,7 +227,7 @@ static irqreturn_t dpc_handler(int irq, void *context)
 	}
 
 	/* We configure DPC so it only triggers on ERR_FATAL */
-	pcie_do_recovery(pdev, pci_channel_io_frozen, PCIE_PORT_SERVICE_DPC);
+	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index eefefe03857a..05f87bc9d011 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -162,14 +162,13 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev)
 	return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
 }
 
-static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
+static pci_ers_result_t reset_link(struct pci_dev *dev,
+			pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
 {
 	pci_ers_result_t status;
-	struct pcie_port_service_driver *driver = NULL;
 
-	driver = pcie_port_find_service(dev, service);
-	if (driver && driver->reset_link) {
-		status = driver->reset_link(dev);
+	if (reset_cb) {
+		status = reset_cb(dev);
 	} else if (pcie_downstream_port(dev)) {
 		status = default_reset_link(dev);
 	} else {
@@ -187,8 +186,9 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
 	return status;
 }
 
-void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
-		      u32 service)
+void pcie_do_recovery(struct pci_dev *dev,
+		      enum pci_channel_state state,
+		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
 {
 	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
 	struct pci_bus *bus;
@@ -209,7 +209,7 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
 		pci_walk_bus(bus, report_normal_detected, &status);
 
 	if (state == pci_channel_io_frozen) {
-		status = reset_link(dev, service);
+		status = reset_link(dev, reset_cb);
 		if (status != PCI_ERS_RESULT_RECOVERED)
 			goto failed;
 	}
-- 
2.21.0

[PATCH v16 4/9] PCI/ERR: Return status of pcie_do_recovery()

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

As per the Downstream Port Containment Related Enhancements ECN to the
PCI Firmware Specification r3.2, sec 4.5.1, table 4-4, Support for Error
Disconnect Recover (EDR) implies that the OS will invalidate the
software state associated with child devices of the port without
attempting to access the child device hardware. If the OS supports
Downstream Port Containment (DPC), as indicated by the OS setting bit 7
of _OSC control field, the OS shall attempt to recover the child devices
if the port implements the Downstream Port Containment Extended
Capability. If the OS continues operation, the OS must inform the
Firmware of the status of the recovery operation via the _OST method.

So in adding EDR support, to report status of error recovery via _OST,
we need to know the status of error recovery. So add support to return
the status of pcie_do_recovery() function.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h      |  5 +++--
 drivers/pci/pcie/err.c | 10 ++++++----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 2962200bfe35..c2c35f152cde 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -547,8 +547,9 @@ static inline int pci_dev_specific_disable_acs_redir(struct pci_dev *dev)
 #endif
 
 /* PCI error reporting and recovery */
-void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
-		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev));
+pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
+			enum pci_channel_state state,
+			pci_ers_result_t (*reset_cb)(struct pci_dev *pdev));
 
 bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
 #ifdef CONFIG_PCIEASPM
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 05f87bc9d011..b560f0096a70 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -186,9 +186,9 @@ static pci_ers_result_t reset_link(struct pci_dev *dev,
 	return status;
 }
 
-void pcie_do_recovery(struct pci_dev *dev,
-		      enum pci_channel_state state,
-		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
+pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
+			enum pci_channel_state state,
+			pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
 {
 	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
 	struct pci_bus *bus;
@@ -240,11 +240,13 @@ void pcie_do_recovery(struct pci_dev *dev,
 	pci_aer_clear_device_status(dev);
 	pci_cleanup_aer_uncorrect_error_status(dev);
 	pci_info(dev, "device recovery successful\n");
-	return;
+	return status;
 
 failed:
 	pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
 
 	/* TODO: Should kernel panic here? */
 	pci_info(dev, "device recovery failed\n");
+
+	return status;
 }
-- 
2.21.0

[PATCH v16 5/9] PCI/DPC: Cache DPC capabilities in pci_init_capabilities()

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Since we need to re-use DPC error handling routines in Error Disconnect
Recover (EDR) driver, move the initalization and caching of DPC
capabilities to pci_init_capabilities().

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/dpc.c | 32 ++++++++++++++++++++------------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index c2c35f152cde..e57e78b619f8 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -448,9 +448,11 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 #ifdef CONFIG_PCIE_DPC
 void pci_save_dpc_state(struct pci_dev *dev);
 void pci_restore_dpc_state(struct pci_dev *dev);
+void pci_dpc_init(struct pci_dev *pdev);
 #else
 static inline void pci_save_dpc_state(struct pci_dev *dev) {}
 static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
+static inline void pci_dpc_init(struct pci_dev *pdev) {}
 #endif
 
 #ifdef CONFIG_PCI_ATS
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 114358d62ddf..57e7f94b98cf 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -249,6 +249,26 @@ static irqreturn_t dpc_irq(int irq, void *context)
 	return IRQ_HANDLED;
 }
 
+void pci_dpc_init(struct pci_dev *pdev)
+{
+	u16 cap;
+
+	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
+	if (!pdev->dpc_cap)
+		return;
+
+	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
+	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
+	if (pdev->dpc_rp_extensions) {
+		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
+		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
+			pci_err(pdev, "RP PIO log size %u is invalid\n",
+				pdev->dpc_rp_log_size);
+			pdev->dpc_rp_log_size = 0;
+		}
+	}
+}
+
 #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
 static int dpc_probe(struct pcie_device *dev)
 {
@@ -260,8 +280,6 @@ static int dpc_probe(struct pcie_device *dev)
 	if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native)
 		return -ENOTSUPP;
 
-	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
-
 	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
 					   dpc_handler, IRQF_SHARED,
 					   "pcie-dpc", pdev);
@@ -274,16 +292,6 @@ static int dpc_probe(struct pcie_device *dev)
 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
 
-	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
-	if (pdev->dpc_rp_extensions) {
-		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
-		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
-			pci_err(pdev, "RP PIO log size %u is invalid\n",
-				pdev->dpc_rp_log_size);
-			pdev->dpc_rp_log_size = 0;
-		}
-	}
-
 	ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
 	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
 
-- 
2.21.0

[PATCH v16 6/9] PCI/AER: Allow clearing Error Status Register in FF mode

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

As per PCI firmware specification r3.2 System Firmware Intermediary
(SFI) _OSC and DPC Updates ECR
(https://members.pcisig.com/wg/PCI-SIG/document/13563), sec titled "DPC
Event Handling Implementation Note", page 10, Error Disconnect Recover
(EDR) support allows OS to handle error recovery and clearing Error
Registers even in FF mode. So create new API pci_aer_raw_clear_status()
which allows clearing AER registers without FF mode checks.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/aer.c | 22 ++++++++++++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index e57e78b619f8..c239e6dd2542 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -655,6 +655,7 @@ extern const struct attribute_group aer_stats_attr_group;
 void pci_aer_clear_fatal_status(struct pci_dev *dev);
 void pci_aer_clear_device_status(struct pci_dev *dev);
 int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
+int pci_aer_raw_clear_status(struct pci_dev *dev);
 #else
 static inline void pci_no_aer(void) { }
 static inline void pci_aer_init(struct pci_dev *d) { }
@@ -665,6 +666,7 @@ static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
 {
 	return -EINVAL;
 }
+int pci_aer_raw_clear_status(struct pci_dev *dev) { return -EINVAL; }
 #endif
 
 #ifdef CONFIG_ACPI
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 1235eca0a2e6..70a1493d8aa6 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -420,7 +420,16 @@ void pci_aer_clear_fatal_status(struct pci_dev *dev)
 		pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);
 }
 
-int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
+/**
+ * pci_aer_raw_clear_status - Clear AER error registers.
+ * @dev: the PCI device
+ *
+ * NOTE: Allows clearing error registers in both FF and
+ * non FF modes.
+ *
+ * Returns 0 on success, or negative on failure.
+ */
+int pci_aer_raw_clear_status(struct pci_dev *dev)
 {
 	int pos;
 	u32 status;
@@ -433,9 +442,6 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
 	if (!pos)
 		return -EIO;
 
-	if (pcie_aer_get_firmware_first(dev))
-		return -EIO;
-
 	port_type = pci_pcie_type(dev);
 	if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
 		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &status);
@@ -451,6 +457,14 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
 	return 0;
 }
 
+int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
+{
+	if (pcie_aer_get_firmware_first(dev))
+		return -EIO;
+
+	return pci_aer_raw_clear_status(dev);
+}
+
 void pci_save_aer_state(struct pci_dev *dev)
 {
 	struct pci_cap_saved_state *save_state;
-- 
2.21.0

[PATCH v16 7/9] PCI/DPC: Export DPC error recovery functions

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

This is a preparatory patch for adding EDR support.

As per the Downstream Port Containment Related Enhancements ECN to the
PCI Firmware Specification r3.2, sec 4.5.1, table 4-6, If DPC is
controlled by firmware, firmware is responsible for initializing
Downstream Port Containment Extended Capability Structures per firmware
policy. Further, the OS is permitted to read or write DPC Control and
Status registers of a port while processing an Error Disconnect Recover
notification from firmware on that port.

To add EDR support we need to re-use DPC error handling functions. So
add necessary interfaces.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/dpc.c | 12 +++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index c239e6dd2542..a475192c553a 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -449,6 +449,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 void pci_save_dpc_state(struct pci_dev *dev);
 void pci_restore_dpc_state(struct pci_dev *dev);
 void pci_dpc_init(struct pci_dev *pdev);
+void dpc_process_error(struct pci_dev *pdev);
+pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
 #else
 static inline void pci_save_dpc_state(struct pci_dev *dev) {}
 static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 57e7f94b98cf..e0a5b5f9547f 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -89,7 +89,7 @@ static int dpc_wait_rp_inactive(struct pci_dev *pdev)
 	return 0;
 }
 
-static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
+pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 {
 	u16 cap;
 
@@ -193,9 +193,8 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
 	return 1;
 }
 
-static irqreturn_t dpc_handler(int irq, void *context)
+void dpc_process_error(struct pci_dev *pdev)
 {
-	struct pci_dev *pdev = context;
 	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
 	struct aer_err_info info;
 
@@ -225,6 +224,13 @@ static irqreturn_t dpc_handler(int irq, void *context)
 		pci_cleanup_aer_uncorrect_error_status(pdev);
 		pci_aer_clear_fatal_status(pdev);
 	}
+}
+
+static irqreturn_t dpc_handler(int irq, void *context)
+{
+	struct pci_dev *pdev = context;
+
+	dpc_process_error(pdev);
 
 	/* We configure DPC so it only triggers on ERR_FATAL */
 	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
-- 
2.21.0

[PATCH v16 8/9] PCI/DPC: Add Error Disconnect Recover (EDR) support

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

As per ACPI specification r6.3, sec 5.6.6, when firmware owns Downstream
Port Containment (DPC), its expected to use the "Error Disconnect
Recover" (EDR) notification to alert OSPM of a DPC event and if OS
supports EDR, its expected to handle the software state invalidation and
port recovery in OS, and also let firmware know the recovery status via
_OST ACPI call. Related _OST status codes can be found in ACPI
specification r6.3, sec 6.3.5.2.

Also, as per PCI firmware specification r3.2 Downstream Port Containment
Related Enhancements ECN, sec 4.5.1, table 4-6, If DPC is controlled by
firmware (firmware first mode), firmware is responsible for
configuring the DPC and OS is responsible for error recovery. Also, OS
is allowed to modify DPC registers only during the EDR notification
window.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pci-acpi.c    |   3 +
 drivers/pci/pcie/Kconfig  |  10 ++
 drivers/pci/pcie/Makefile |   1 +
 drivers/pci/pcie/edr.c    | 249 ++++++++++++++++++++++++++++++++++++++
 include/linux/pci-acpi.h  |   8 ++
 5 files changed, 271 insertions(+)
 create mode 100644 drivers/pci/pcie/edr.c

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 0c02d500158f..6af5d6a04990 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1258,6 +1258,7 @@ static void pci_acpi_setup(struct device *dev)
 
 	acpi_pci_wakeup(pci_dev, false);
 	acpi_device_power_add_dependent(adev, dev);
+	pci_acpi_add_edr_notifier(pci_dev);
 }
 
 static void pci_acpi_cleanup(struct device *dev)
@@ -1276,6 +1277,8 @@ static void pci_acpi_cleanup(struct device *dev)
 
 		device_set_wakeup_capable(dev, false);
 	}
+
+	pci_acpi_remove_edr_notifier(pci_dev);
 }
 
 static bool pci_acpi_bus_match(struct device *dev)
diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig
index 6e3c04b46fb1..772b1f4cb19e 100644
--- a/drivers/pci/pcie/Kconfig
+++ b/drivers/pci/pcie/Kconfig
@@ -140,3 +140,13 @@ config PCIE_BW
 	  This enables PCI Express Bandwidth Change Notification.  If
 	  you know link width or rate changes occur only to correct
 	  unreliable links, you may answer Y.
+
+config PCIE_EDR
+	bool "PCI Express Error Disconnect Recover support"
+	depends on PCIE_DPC && ACPI
+	help
+	  This option adds Error Disconnect Recover support as specified
+	  in the Downstream Port Containment Related Enhancements ECN to
+	  the PCI Firmware Specification r3.2.  Enable this if you want to
+	  support hybrid DPC model which uses both firmware and OS to
+	  implement DPC.
diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
index efb9d2e71e9e..68da9280ff11 100644
--- a/drivers/pci/pcie/Makefile
+++ b/drivers/pci/pcie/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_PCIE_PME)		+= pme.o
 obj-$(CONFIG_PCIE_DPC)		+= dpc.o
 obj-$(CONFIG_PCIE_PTM)		+= ptm.o
 obj-$(CONFIG_PCIE_BW)		+= bw_notification.o
+obj-$(CONFIG_PCIE_EDR)		+= edr.o
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
new file mode 100644
index 000000000000..2d8680be0302
--- /dev/null
+++ b/drivers/pci/pcie/edr.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI DPC Error Disconnect Recover support driver
+ * Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
+ *
+ * Copyright (C) 2020 Intel Corp.
+ */
+
+#define dev_fmt(fmt) "EDR: " fmt
+
+#include <linux/pci.h>
+#include <linux/pci-acpi.h>
+
+#include "portdrv.h"
+#include "../pci.h"
+
+#define EDR_PORT_ENABLE_DSM		0x0C
+#define EDR_PORT_LOCATE_DSM		0x0D
+#define EDR_OST_SUCCESS			0x80
+#define EDR_OST_FAILED			0x81
+
+/*
+ * _DSM wrapper function to enable/disable DPC port.
+ * @pdev   : PCI device structure.
+ *
+ * returns 0 on success or errno on failure.
+ */
+static int acpi_enable_dpc_port(struct pci_dev *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	union acpi_object *obj, argv4, req;
+	int status = 0;
+
+	req.type = ACPI_TYPE_INTEGER;
+	req.integer.value = 1;
+
+	argv4.type = ACPI_TYPE_PACKAGE;
+	argv4.package.count = 1;
+	argv4.package.elements = &req;
+
+	/*
+	 * Per the Downstream Port Containment Related Enhancements ECN to
+	 * the PCI Firmware Specification r3.2, sec 4.6.12,
+	 * EDR_PORT_ENABLE_DSM is optional.  Return success if it's not
+	 * implemented.
+	 */
+	obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
+				EDR_PORT_ENABLE_DSM, &argv4);
+	if (!obj)
+		return 0;
+
+	if (obj->type != ACPI_TYPE_INTEGER) {
+		pci_err(pdev, "_DSM 0x0C returns non integer value\n");
+		status = -EIO;
+	}
+
+	if (obj->integer.value != 1) {
+		pci_err(pdev, "failed to enable DPC port\n");
+		status = -EIO;
+	}
+
+	ACPI_FREE(obj);
+
+	return status;
+}
+
+/*
+ * _DSM wrapper function to locate DPC port.
+ * @pdev   : Device which received EDR event.
+ *
+ * returns pci_dev or NULL.
+ */
+static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	union acpi_object *obj;
+	u16 port;
+
+	obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
+				EDR_PORT_LOCATE_DSM, NULL);
+	if (!obj)
+		return pci_dev_get(pdev);
+
+	if (obj->type != ACPI_TYPE_INTEGER) {
+		ACPI_FREE(obj);
+		pci_err(pdev, "_DSM 0x0D returns non integer value\n");
+		return NULL;
+	}
+
+	/*
+	 * Firmware returns DPC port BDF details in following format:
+	 *	15:8 = bus
+	 *	 7:3 = device
+	 *	 2:0 = function
+	 */
+	port = obj->integer.value;
+
+	ACPI_FREE(obj);
+
+	return pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
+					   PCI_BUS_NUM(port), port & 0xff);
+}
+
+/*
+ * _OST wrapper function to let firmware know the status of EDR event.
+ * @pdev   : Device used to send _OST.
+ * @edev   : Device which experienced EDR event.
+ * @status: Status of EDR event.
+ */
+static int acpi_send_edr_status(struct pci_dev *pdev, struct pci_dev *edev,
+				u16 status)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	u32 ost_status;
+
+	pci_dbg(pdev, "Sending EDR status :%#x\n", status);
+
+	ost_status =  PCI_DEVID(edev->bus->number, edev->devfn);
+	ost_status = (ost_status << 16) | status;
+
+	status = acpi_evaluate_ost(adev->handle,
+				   ACPI_NOTIFY_DISCONNECT_RECOVER,
+				   ost_status, NULL);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void edr_handle_event(acpi_handle handle, u32 event, void *data)
+{
+	struct pci_dev *pdev = data, *edev;
+	pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
+	u16 status;
+
+	pci_info(pdev, "ACPI event %#x received\n", event);
+
+	if (event != ACPI_NOTIFY_DISCONNECT_RECOVER)
+		return;
+
+	/*
+	 * Check if _DSM(0xD) is available, and if present locate the
+	 * port which issued EDR event.
+	 */
+	edev = acpi_dpc_port_get(pdev);
+	if (!edev) {
+		pci_err(pdev, "Firmware failed to locate DPC port\n");
+		return;
+	}
+
+	pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev));
+
+	/*
+	 * If port does not support DPC, just send the OST:
+	 */
+	if (!edev->dpc_cap) {
+		pci_err(edev, "Firmware BUG, located port doesn't support DPC\n");
+		goto send_ost;
+	}
+
+	/* Check if there is a valid DPC trigger */
+	pci_read_config_word(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
+	if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
+		pci_err(edev, "Invalid DPC trigger %#010x\n", status);
+		goto send_ost;
+	}
+
+	dpc_process_error(edev);
+
+	/* Clear AER registers */
+	pci_aer_raw_clear_status(edev);
+
+	/*
+	 * Irrespective of whether the DPC event is triggered by
+	 * ERR_FATAL or ERR_NONFATAL, since the link is already down,
+	 * use the FATAL error recovery path for both cases.
+	 */
+	estate = pcie_do_recovery(edev, pci_channel_io_frozen, dpc_reset_link);
+
+	pci_dbg(edev, "DPC port successfully recovered\n");
+send_ost:
+
+	/*
+	 * If recovery is successful, send _OST(0xF, BDF << 16 | 0x80)
+	 * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81).
+	 */
+	if (estate == PCI_ERS_RESULT_RECOVERED)
+		acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS);
+	else
+		acpi_send_edr_status(pdev, edev, EDR_OST_FAILED);
+
+	pci_dev_put(edev);
+}
+
+void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	acpi_status astatus;
+
+	if (!adev) {
+		pci_dbg(pdev, "No valid ACPI node, so skip EDR init\n");
+		return;
+	}
+
+	/*
+	 * Per the Downstream Port Containment Related Enhancements ECN to
+	 * the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-6, EDR support
+	 * can only be enabled if DPC is controlled by firmware.
+	 *
+	 * TODO: Remove dependency on ACPI FIRMWARE_FIRST bit to
+	 * determine ownership of DPC between firmware or OS.
+	 * Per the Downstream Port Containment Related Enhancements
+	 * ECN to the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-5,
+	 * OS can use bit 7 of _OSC control field to negotiate control
+	 * over DPC Capability.
+	 */
+	if (!pcie_aer_get_firmware_first(pdev) || pcie_ports_dpc_native) {
+		pci_dbg(pdev, "OS handles AER/DPC, so skip EDR init\n");
+		return;
+	}
+
+	astatus = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
+					      edr_handle_event, pdev);
+	if (ACPI_FAILURE(astatus)) {
+		pci_err(pdev, "Install ACPI_SYSTEM_NOTIFY handler failed\n");
+		return;
+	}
+
+	if (acpi_enable_dpc_port(pdev))
+		acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
+					   edr_handle_event);
+
+	pci_dbg(pdev, "EDR notifier is added successfully\n");
+
+	return;
+}
+
+void pci_acpi_remove_edr_notifier(struct pci_dev *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+
+	if (!adev)
+		return;
+
+	pci_dbg(pdev, "EDR notifier is removed successfully\n");
+
+	acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
+				   edr_handle_event);
+}
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 62b7fdcc661c..2d155bfb8fbf 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -112,6 +112,14 @@ extern const guid_t pci_acpi_dsm_guid;
 #define RESET_DELAY_DSM			0x08
 #define FUNCTION_DELAY_DSM		0x09
 
+#ifdef CONFIG_PCIE_EDR
+void pci_acpi_add_edr_notifier(struct pci_dev *pdev);
+void pci_acpi_remove_edr_notifier(struct pci_dev *pdev);
+#else
+static inline void pci_acpi_add_edr_notifier(struct pci_dev *pdev) { }
+static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { }
+#endif /* CONFIG_PCIE_EDR */
+
 #else	/* CONFIG_ACPI */
 static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
 static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
-- 
2.21.0

[PATCH v16 9/9] PCI/ACPI: Enable EDR support

[sathyanarayanan.kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

As per PCI firmware specification r3.2 Downstream Port Containment
Related Enhancements ECN, sec 4.5.1, OS must implement following steps
to enable/use EDR feature.

1. OS can use bit 7 of _OSC Control Field to negotiate control over
Downstream Port Containment (DPC) configuration of PCIe port. After _OSC
negotiation, firmware will Set this bit to grant OS control over PCIe
DPC configuration and Clear it if this feature was requested and denied,
or was not requested.

2. Also, if OS supports EDR, it should expose its support to BIOS by
setting bit 7 of _OSC Support Field. And if OS sets bit 7 of _OSC
Control Field it must also expose support for EDR by setting bit 7 of
_OSC Support Field.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Keith Busch <keith.busch@intel.com>
Tested-by: Huong Nguyen <huong.nguyen@dell.com>
Tested-by: Austin Bolen <Austin.Bolen@dell.com>
---
 drivers/acpi/pci_root.c | 16 ++++++++++++++++
 drivers/pci/pcie/edr.c  |  4 +++-
 drivers/pci/probe.c     |  1 +
 include/linux/acpi.h    |  6 ++++--
 include/linux/pci.h     |  1 +
 5 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d1e666ef3fcc..ad1be5941a00 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -131,6 +131,7 @@ static struct pci_osc_bit_struct pci_osc_support_bit[] = {
 	{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
 	{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
 	{ OSC_PCI_MSI_SUPPORT, "MSI" },
+	{ OSC_PCI_EDR_SUPPORT, "EDR" },
 	{ OSC_PCI_HPX_TYPE_3_SUPPORT, "HPX-Type3" },
 };
 
@@ -141,6 +142,7 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
 	{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
 	{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
 	{ OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" },
+	{ OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" },
 };
 
 static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
@@ -440,6 +442,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
 		support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
 	if (pci_msi_enabled())
 		support |= OSC_PCI_MSI_SUPPORT;
+	if (IS_ENABLED(CONFIG_PCIE_EDR))
+		support |= OSC_PCI_EDR_SUPPORT;
 
 	decode_osc_support(root, "OS supports", support);
 	status = acpi_pci_osc_support(root, support);
@@ -487,6 +491,16 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
 			control |= OSC_PCI_EXPRESS_AER_CONTROL;
 	}
 
+	/*
+	 * Per the Downstream Port Containment Related Enhancements ECN to
+	 * the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-5,
+	 * OSC_PCI_EXPRESS_DPC_CONTROL indicates the OS supports both DPC
+	 * and EDR. So use CONFIG_PCIE_EDR for requesting DPC control which
+	 * will only be turned on if both EDR and DPC is enabled.
+	 */
+	if (IS_ENABLED(CONFIG_PCIE_EDR))
+		control |= OSC_PCI_EXPRESS_DPC_CONTROL;
+
 	requested = control;
 	status = acpi_pci_osc_control_set(handle, &control,
 					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
@@ -916,6 +930,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 		host_bridge->native_pme = 0;
 	if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
 		host_bridge->native_ltr = 0;
+	if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
+		host_bridge->native_dpc = 0;
 
 	/*
 	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index 2d8680be0302..45d165e838bb 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -195,6 +195,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
 void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
 	acpi_status astatus;
 
 	if (!adev) {
@@ -214,7 +215,8 @@ void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
 	 * OS can use bit 7 of _OSC control field to negotiate control
 	 * over DPC Capability.
 	 */
-	if (!pcie_aer_get_firmware_first(pdev) || pcie_ports_dpc_native) {
+	if (!pcie_aer_get_firmware_first(pdev) || pcie_ports_dpc_native ||
+	    (host->native_dpc)) {
 		pci_dbg(pdev, "OS handles AER/DPC, so skip EDR init\n");
 		return;
 	}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 512cb4312ddd..c9a9c5b42e72 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -598,6 +598,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
 	bridge->native_shpc_hotplug = 1;
 	bridge->native_pme = 1;
 	bridge->native_ltr = 1;
+	bridge->native_dpc = 1;
 }
 
 struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 0f24d701fbdc..b7d3caf6f205 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -530,8 +530,9 @@ extern bool osc_pc_lpi_support_confirmed;
 #define OSC_PCI_CLOCK_PM_SUPPORT		0x00000004
 #define OSC_PCI_SEGMENT_GROUPS_SUPPORT		0x00000008
 #define OSC_PCI_MSI_SUPPORT			0x00000010
+#define OSC_PCI_EDR_SUPPORT			0x00000080
 #define OSC_PCI_HPX_TYPE_3_SUPPORT		0x00000100
-#define OSC_PCI_SUPPORT_MASKS			0x0000011f
+#define OSC_PCI_SUPPORT_MASKS			0x0000019f
 
 /* PCI Host Bridge _OSC: Capabilities DWORD 3: Control Field */
 #define OSC_PCI_EXPRESS_NATIVE_HP_CONTROL	0x00000001
@@ -540,7 +541,8 @@ extern bool osc_pc_lpi_support_confirmed;
 #define OSC_PCI_EXPRESS_AER_CONTROL		0x00000008
 #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL	0x00000010
 #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
-#define OSC_PCI_CONTROL_MASKS			0x0000003f
+#define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
+#define OSC_PCI_CONTROL_MASKS			0x000000bf
 
 #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
 #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a0b7e7a53741..7ed7c088c952 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -515,6 +515,7 @@ struct pci_host_bridge {
 	unsigned int	native_shpc_hotplug:1;	/* OS may use SHPC hotplug */
 	unsigned int	native_pme:1;		/* OS may use PCIe PME */
 	unsigned int	native_ltr:1;		/* OS may use PCIe LTR */
+	unsigned int	native_dpc:1;		/* OS may use PCIe DPC */
 	unsigned int	preserve_config:1;	/* Preserve FW resource setup */
 
 	/* Resource alignment requirements */
-- 
2.21.0

Re: [PATCH v16 3/9] PCI/ERR: Remove service dependency in pcie_do_recovery()

[Bjorn Helgaas]

On Thu, Feb 27, 2020 at 04:59:45PM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> Currently we pass PCIe service type parameter to pcie_do_recovery()
> function which was in-turn used by reset_link() function to identify
> the underlying pci_port_service_driver and then initiate the driver
> specific reset_link call. Instead of using this roundabout way, we
> can just pass the driver specific reset_link callback function when
> calling pcie_do_recovery() function.

I love this!  And I think pcie_port_find_service() is now unused.  I
can add a patch to remove it.

> This change will also enable non PCIe service driver to call
> pcie_do_recovery() function. This is required for adding Error
> Disconnect Recover (EDR) support.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/pci/pci.h      |  2 +-
>  drivers/pci/pcie/aer.c | 11 +++++------
>  drivers/pci/pcie/dpc.c |  2 +-
>  drivers/pci/pcie/err.c | 16 ++++++++--------
>  4 files changed, 15 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index a4c360515a69..2962200bfe35 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -548,7 +548,7 @@ static inline int pci_dev_specific_disable_acs_redir(struct pci_dev *dev)
>  
>  /* PCI error reporting and recovery */
>  void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
> -		      u32 service);
> +		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev));
>  
>  bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
>  #ifdef CONFIG_PCIEASPM
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 4a818b07a1af..1235eca0a2e6 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -102,6 +102,7 @@ struct aer_stats {
>  #define ERR_UNCOR_ID(d)			(d >> 16)
>  
>  static int pcie_aer_disable;
> +static pci_ers_result_t aer_root_reset(struct pci_dev *dev);
>  
>  void pci_no_aer(void)
>  {
> @@ -1053,11 +1054,9 @@ static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
>  					info->status);
>  		pci_aer_clear_device_status(dev);
>  	} else if (info->severity == AER_NONFATAL)
> -		pcie_do_recovery(dev, pci_channel_io_normal,
> -				 PCIE_PORT_SERVICE_AER);
> +		pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
>  	else if (info->severity == AER_FATAL)
> -		pcie_do_recovery(dev, pci_channel_io_frozen,
> -				 PCIE_PORT_SERVICE_AER);
> +		pcie_do_recovery(dev, pci_channel_io_frozen, aer_root_reset);
>  	pci_dev_put(dev);
>  }
>  
> @@ -1094,10 +1093,10 @@ static void aer_recover_work_func(struct work_struct *work)
>  		cper_print_aer(pdev, entry.severity, entry.regs);
>  		if (entry.severity == AER_NONFATAL)
>  			pcie_do_recovery(pdev, pci_channel_io_normal,
> -					 PCIE_PORT_SERVICE_AER);
> +					 aer_root_reset);
>  		else if (entry.severity == AER_FATAL)
>  			pcie_do_recovery(pdev, pci_channel_io_frozen,
> -					 PCIE_PORT_SERVICE_AER);
> +					 aer_root_reset);
>  		pci_dev_put(pdev);
>  	}
>  }
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 6b116d7fdb89..114358d62ddf 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -227,7 +227,7 @@ static irqreturn_t dpc_handler(int irq, void *context)
>  	}
>  
>  	/* We configure DPC so it only triggers on ERR_FATAL */
> -	pcie_do_recovery(pdev, pci_channel_io_frozen, PCIE_PORT_SERVICE_DPC);
> +	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
>  
>  	return IRQ_HANDLED;
>  }
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index eefefe03857a..05f87bc9d011 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -162,14 +162,13 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev)
>  	return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
>  }
>  
> -static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
> +static pci_ers_result_t reset_link(struct pci_dev *dev,
> +			pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
>  {
>  	pci_ers_result_t status;
> -	struct pcie_port_service_driver *driver = NULL;
>  
> -	driver = pcie_port_find_service(dev, service);
> -	if (driver && driver->reset_link) {
> -		status = driver->reset_link(dev);
> +	if (reset_cb) {
> +		status = reset_cb(dev);
>  	} else if (pcie_downstream_port(dev)) {
>  		status = default_reset_link(dev);
>  	} else {
> @@ -187,8 +186,9 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
>  	return status;
>  }
>  
> -void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
> -		      u32 service)
> +void pcie_do_recovery(struct pci_dev *dev,
> +		      enum pci_channel_state state,
> +		      pci_ers_result_t (*reset_cb)(struct pci_dev *pdev))
>  {
>  	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
>  	struct pci_bus *bus;
> @@ -209,7 +209,7 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
>  		pci_walk_bus(bus, report_normal_detected, &status);
>  
>  	if (state == pci_channel_io_frozen) {
> -		status = reset_link(dev, service);
> +		status = reset_link(dev, reset_cb);
>  		if (status != PCI_ERS_RESULT_RECOVERED)
>  			goto failed;
>  	}
> -- 
> 2.21.0
> 

Re: [PATCH v16 3/9] PCI/ERR: Remove service dependency in pcie_do_recovery()

[Kuppuswamy, Sathyanarayanan]

Hi Bjorn,

On 3/3/2020 9:04 AM, Bjorn Helgaas wrote:
> On Thu, Feb 27, 2020 at 04:59:45PM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>
>> Currently we pass PCIe service type parameter to pcie_do_recovery()
>> function which was in-turn used by reset_link() function to identify
>> the underlying pci_port_service_driver and then initiate the driver
>> specific reset_link call. Instead of using this roundabout way, we
>> can just pass the driver specific reset_link callback function when
>> calling pcie_do_recovery() function.
> 
> I love this!  And I think pcie_port_find_service() is now unused.  I
> can add a patch to remove it.
I can submit a patch to remove it in next version.

Along with this, I think we also need to remove reset_link pointer from 
pcie_port_service_driver. Also we need to make relevant changes in 
Documentation/PCI/pcieaer-howto.rst as well.

I will wait for you to review rest of the patches before sending the 
next version. Please let me know if you want me to just fix this and 
send it.

> -- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v16 5/9] PCI/DPC: Cache DPC capabilities in pci_init_capabilities()

[Bjorn Helgaas]

On Thu, Feb 27, 2020 at 04:59:47PM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> Since we need to re-use DPC error handling routines in Error Disconnect
> Recover (EDR) driver, move the initalization and caching of DPC
> capabilities to pci_init_capabilities().
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/pci/pci.h      |  2 ++
>  drivers/pci/pcie/dpc.c | 32 ++++++++++++++++++++------------
>  2 files changed, 22 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index c2c35f152cde..e57e78b619f8 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -448,9 +448,11 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
>  #ifdef CONFIG_PCIE_DPC
>  void pci_save_dpc_state(struct pci_dev *dev);
>  void pci_restore_dpc_state(struct pci_dev *dev);
> +void pci_dpc_init(struct pci_dev *pdev);
>  #else
>  static inline void pci_save_dpc_state(struct pci_dev *dev) {}
>  static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
> +static inline void pci_dpc_init(struct pci_dev *pdev) {}
>  #endif
>  
>  #ifdef CONFIG_PCI_ATS
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 114358d62ddf..57e7f94b98cf 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -249,6 +249,26 @@ static irqreturn_t dpc_irq(int irq, void *context)
>  	return IRQ_HANDLED;
>  }
>  
> +void pci_dpc_init(struct pci_dev *pdev)
> +{

I think you forgot to call this?

> +	u16 cap;
> +
> +	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
> +	if (!pdev->dpc_cap)
> +		return;
> +
> +	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
> +	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
> +	if (pdev->dpc_rp_extensions) {
> +		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> +		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
> +			pci_err(pdev, "RP PIO log size %u is invalid\n",
> +				pdev->dpc_rp_log_size);
> +			pdev->dpc_rp_log_size = 0;
> +		}
> +	}
> +}
> +
>  #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
>  static int dpc_probe(struct pcie_device *dev)
>  {
> @@ -260,8 +280,6 @@ static int dpc_probe(struct pcie_device *dev)
>  	if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native)
>  		return -ENOTSUPP;
>  
> -	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
> -
>  	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
>  					   dpc_handler, IRQF_SHARED,
>  					   "pcie-dpc", pdev);
> @@ -274,16 +292,6 @@ static int dpc_probe(struct pcie_device *dev)
>  	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
>  	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
>  
> -	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
> -	if (pdev->dpc_rp_extensions) {
> -		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> -		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
> -			pci_err(pdev, "RP PIO log size %u is invalid\n",
> -				pdev->dpc_rp_log_size);
> -			pdev->dpc_rp_log_size = 0;
> -		}
> -	}
> -
>  	ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
>  	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
>  
> -- 
> 2.21.0
> 

Re: [PATCH v16 5/9] PCI/DPC: Cache DPC capabilities in pci_init_capabilities()

[Kuppuswamy, Sathyanarayanan]

On 3/3/2020 4:47 PM, Bjorn Helgaas wrote:
> I think you forgot to call this?

Sorry about it. It looks like I missed adding probe.c 
pci_init_capabilities() changes. Let me fix it and send a new version.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v16 7/9] PCI/DPC: Export DPC error recovery functions

[Christoph Hellwig]

Please fix your subject.  Nothing is being exported in this patch.

Re: [PATCH v16 7/9] PCI/DPC: Export DPC error recovery functions

[Kuppuswamy Sathyanarayanan]

Hi,

On 3/5/20 8:37 AM, Christoph Hellwig wrote:
> Please fix your subject.  Nothing is being exported in this patch.
I will do it. I meant it as its being used outside dpc..

-- 
Sathyanarayanan Kuppuswamy
Linux kernel developer

Re: [PATCH v16 7/9] PCI/DPC: Export DPC error recovery functions

[Bjorn Helgaas]

On Thu, Mar 05, 2020 at 09:42:21AM -0800, Kuppuswamy Sathyanarayanan wrote:
> Hi,
> 
> On 3/5/20 8:37 AM, Christoph Hellwig wrote:
> > Please fix your subject.  Nothing is being exported in this patch.
> I will do it. I meant it as its being used outside dpc..

I'll update this.  I have some other tweaks so I'll post an updated
series soon.

Re: [PATCH v16 7/9] PCI/DPC: Export DPC error recovery functions

[Kuppuswamy Sathyanarayanan]

Hi Bjorn,

On 3/5/20 10:59 AM, Bjorn Helgaas wrote:
> On Thu, Mar 05, 2020 at 09:42:21AM -0800, Kuppuswamy Sathyanarayanan wrote:
>> Hi,
>>
>> On 3/5/20 8:37 AM, Christoph Hellwig wrote:
>>> Please fix your subject.  Nothing is being exported in this patch.
>> I will do it. I meant it as its being used outside dpc..
> I'll update this.  I have some other tweaks so I'll post an updated
> series soon.
In case if you haven't noticed, I have posted v17 version of it. please 
apply
your changes on top of it.

-- 
Sathyanarayanan Kuppuswamy
Linux kernel developer