[RFC PATCH v1 1/2] PCI/AER: run recovery on device that detected the error

[Shuai Xue <xueshuai@linux.alibaba.com>]

The current implementation of pcie_do_recovery() assumes that the
recovery process is executed on the device that detected the error.
However, the DPC driver currently passes the error port that experienced
the DPC event to pcie_do_recovery().

Use the SOURCE ID register to correctly identify the device that detected the
error. By passing this error-detecting device to pcie_do_recovery(), subsequent
patches will be able to accurately access the AER error status.

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
---
 drivers/pci/pci.h      |  2 +-
 drivers/pci/pcie/dpc.c | 30 ++++++++++++++++++++++++------
 drivers/pci/pcie/edr.c | 35 ++++++++++++++++++-----------------
 3 files changed, 43 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 14d00ce45bfa..0866f79aec54 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -521,7 +521,7 @@ struct rcec_ea {
 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);
+struct pci_dev *dpc_process_error(struct pci_dev *pdev);
 pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
 bool pci_dpc_recovered(struct pci_dev *pdev);
 #else
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 2b6ef7efa3c1..62a68cde4364 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -257,10 +257,17 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
 	return 1;
 }
 
-void dpc_process_error(struct pci_dev *pdev)
+/**
+ * dpc_process_error - handle the DPC error status
+ * @pdev: the port that experienced the containment event
+ *
+ * Return the device that experienced the error.
+ */
+struct pci_dev *dpc_process_error(struct pci_dev *pdev)
 {
 	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
 	struct aer_err_info info;
+	struct pci_dev *err_dev = NULL;
 
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
@@ -283,6 +290,13 @@ void dpc_process_error(struct pci_dev *pdev)
 		 "software trigger" :
 		 "reserved error");
 
+	if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE ||
+	    reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE)
+		err_dev = pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
+					    PCI_BUS_NUM(source), source & 0xff);
+	else
+		err_dev = pci_dev_get(pdev);
+
 	/* show RP PIO error detail information */
 	if (pdev->dpc_rp_extensions &&
 	    reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
@@ -295,6 +309,8 @@ void dpc_process_error(struct pci_dev *pdev)
 		pci_aer_clear_nonfatal_status(pdev);
 		pci_aer_clear_fatal_status(pdev);
 	}
+
+	return err_dev;
 }
 
 static void pci_clear_surpdn_errors(struct pci_dev *pdev)
@@ -350,21 +366,23 @@ static bool dpc_is_surprise_removal(struct pci_dev *pdev)
 
 static irqreturn_t dpc_handler(int irq, void *context)
 {
-	struct pci_dev *pdev = context;
+	struct pci_dev *err_port = context, *err_dev = NULL;
 
 	/*
 	 * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
 	 * of async removal and should be ignored by software.
 	 */
-	if (dpc_is_surprise_removal(pdev)) {
-		dpc_handle_surprise_removal(pdev);
+	if (dpc_is_surprise_removal(err_port)) {
+		dpc_handle_surprise_removal(err_port);
 		return IRQ_HANDLED;
 	}
 
-	dpc_process_error(pdev);
+	err_dev = dpc_process_error(err_port);
 
 	/* We configure DPC so it only triggers on ERR_FATAL */
-	pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
+	pcie_do_recovery(err_dev, pci_channel_io_frozen, dpc_reset_link);
+
+	pci_dev_put(err_dev);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index e86298dbbcff..6ac95e5e001b 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -150,7 +150,7 @@ static int acpi_send_edr_status(struct pci_dev *pdev, struct pci_dev *edev,
 
 static void edr_handle_event(acpi_handle handle, u32 event, void *data)
 {
-	struct pci_dev *pdev = data, *edev;
+	struct pci_dev *pdev = data, *err_port, *err_dev = NULL;
 	pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
 	u16 status;
 
@@ -169,36 +169,36 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
 	 * may be that port or a parent of it (PCI Firmware r3.3, sec
 	 * 4.6.13).
 	 */
-	edev = acpi_dpc_port_get(pdev);
-	if (!edev) {
+	err_port = acpi_dpc_port_get(pdev);
+	if (!err_port) {
 		pci_err(pdev, "Firmware failed to locate DPC port\n");
 		return;
 	}
 
-	pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev));
+	pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(err_port));
 
 	/* If port does not support DPC, just send the OST */
-	if (!edev->dpc_cap) {
-		pci_err(edev, FW_BUG "This device doesn't support DPC\n");
+	if (!err_port->dpc_cap) {
+		pci_err(err_port, FW_BUG "This device 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);
+	pci_read_config_word(err_port, err_port->dpc_cap + PCI_EXP_DPC_STATUS, &status);
 	if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
-		pci_err(edev, "Invalid DPC trigger %#010x\n", status);
+		pci_err(err_port, "Invalid DPC trigger %#010x\n", status);
 		goto send_ost;
 	}
 
-	dpc_process_error(edev);
-	pci_aer_raw_clear_status(edev);
+	err_dev = dpc_process_error(err_port);
+	pci_aer_raw_clear_status(err_port);
 
 	/*
 	 * 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);
+	estate = pcie_do_recovery(err_dev, pci_channel_io_frozen, dpc_reset_link);
 
 send_ost:
 
@@ -207,15 +207,16 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
 	 * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81).
 	 */
 	if (estate == PCI_ERS_RESULT_RECOVERED) {
-		pci_dbg(edev, "DPC port successfully recovered\n");
-		pcie_clear_device_status(edev);
-		acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS);
+		pci_dbg(err_port, "DPC port successfully recovered\n");
+		pcie_clear_device_status(err_port);
+		acpi_send_edr_status(pdev, err_port, EDR_OST_SUCCESS);
 	} else {
-		pci_dbg(edev, "DPC port recovery failed\n");
-		acpi_send_edr_status(pdev, edev, EDR_OST_FAILED);
+		pci_dbg(err_port, "DPC port recovery failed\n");
+		acpi_send_edr_status(pdev, err_port, EDR_OST_FAILED);
 	}
 
-	pci_dev_put(edev);
+	pci_dev_put(err_port);
+	pci_dev_put(err_dev);
 }
 
 void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
-- 
2.39.3