[PATCH v9 7/7] PCI/DPC: Enumerate the devices after DPC trigger event

From: Oza Pawandeep
Date: Thu Feb 22 2018 - 02:46:57 EST


Implement error_resume callback in DPC so, after DPC trigger event
enumerates the devices beneath.

Signed-off-by: Oza Pawandeep <poza@xxxxxxxxxxxxxx>

diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
index fce4518..59c01c7 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -129,6 +129,23 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
}

/**
+ * dpc_error_resume - enumerate the devices beneath
+ * @dev: pointer to Root Port's pci_dev data structure
+ *
+ * Invoked by Port Bus driver during nonfatal recovery.
+ */
+static void dpc_error_resume(struct pci_dev *pdev)
+{
+ bool active = true;
+
+ if (pci_wait_for_link(pdev, active)) {
+ pci_lock_rescan_remove();
+ pci_rescan_bus(pdev->bus);
+ pci_unlock_rescan_remove();
+ }
+}
+
+/**
* dpc_reset_link - reset link DPC routine
* @dev: pointer to Root Port's pci_dev data structure
*
@@ -366,6 +383,7 @@ static void dpc_remove(struct pcie_device *dev)
.service = PCIE_PORT_SERVICE_DPC,
.probe = dpc_probe,
.remove = dpc_remove,
+ .error_resume = dpc_error_resume,
.reset_link = dpc_reset_link,
};

diff --git a/drivers/pci/pcie/pcie-err.c b/drivers/pci/pcie/pcie-err.c
index 6844347..4950f49 100644
--- a/drivers/pci/pcie/pcie-err.c
+++ b/drivers/pci/pcie/pcie-err.c
@@ -236,6 +236,7 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
* @state: error state
* @error_mesg: message to print
* @cb: callback to be broadcasted
+ * @severity: error severity
*
* Invoked during error recovery process. Once being invoked, the content
* of error severity will be broadcasted to all downstream drivers in a
@@ -244,7 +245,8 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
enum pci_channel_state state,
char *error_mesg,
- int (*cb)(struct pci_dev *, void *))
+ int (*cb)(struct pci_dev *, void *),
+ int severity)
{
struct aer_broadcast_data result_data;

@@ -256,6 +258,15 @@ static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
result_data.result = PCI_ERS_RESULT_RECOVERED;

if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ /* If DPC is triggered, call resume error hanlder
+ * because, at this point we can safely assume that
+ * link recovery has happened.
+ */
+ if ((severity == DPC_FATAL) &&
+ (cb == report_resume)) {
+ cb(dev, NULL);
+ return PCI_ERS_RESULT_RECOVERED;
+ }
/*
* If the error is reported by a bridge, we think this error
* is related to the downstream link of the bridge, so we
@@ -305,7 +316,8 @@ void pci_do_recovery(struct pci_dev *dev, int severity)
status = broadcast_error_message(dev,
state,
"error_detected",
- report_error_detected);
+ report_error_detected,
+ severity);

if ((severity == AER_FATAL) ||
(severity == DPC_FATAL)) {
@@ -321,7 +333,8 @@ void pci_do_recovery(struct pci_dev *dev, int severity)
status = broadcast_error_message(dev,
state,
"mmio_enabled",
- report_mmio_enabled);
+ report_mmio_enabled,
+ severity);

if (status == PCI_ERS_RESULT_NEED_RESET) {
/*
@@ -332,7 +345,8 @@ void pci_do_recovery(struct pci_dev *dev, int severity)
status = broadcast_error_message(dev,
state,
"slot_reset",
- report_slot_reset);
+ report_slot_reset,
+ severity);
}

if (status != PCI_ERS_RESULT_RECOVERED)
@@ -342,7 +356,8 @@ void pci_do_recovery(struct pci_dev *dev, int severity)
broadcast_error_message(dev,
state,
"resume",
- report_resume);
+ report_resume,
+ severity);

dev_info(&dev->dev, "Device recovery successful\n");
mutex_unlock(&pci_err_recovery_lock);
--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.,
a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.