1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
new file mode 100644
index 000000000..59c90d04a
--- /dev/null
+++ b/drivers/pci/pcie/err.c
@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file implements the error recovery as a core part of PCIe error
+ * reporting. When a PCIe error is delivered, an error message will be
+ * collected and printed to console, then, an error recovery procedure
+ * will be executed by following the PCI error recovery rules.
+ *
+ * Copyright (C) 2006 Intel Corp.
+ *	Tom Long Nguyen (tom.l.nguyen@intel.com)
+ *	Zhang Yanmin (yanmin.zhang@intel.com)
+ */
+
+#define dev_fmt(fmt) "AER: " fmt
+
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/aer.h>
+#include "portdrv.h"
+#include "../pci.h"
+
+static pci_ers_result_t merge_result(enum pci_ers_result orig,
+				  enum pci_ers_result new)
+{
+	if (new == PCI_ERS_RESULT_NO_AER_DRIVER)
+		return PCI_ERS_RESULT_NO_AER_DRIVER;
+
+	if (new == PCI_ERS_RESULT_NONE)
+		return orig;
+
+	switch (orig) {
+	case PCI_ERS_RESULT_CAN_RECOVER:
+	case PCI_ERS_RESULT_RECOVERED:
+		orig = new;
+		break;
+	case PCI_ERS_RESULT_DISCONNECT:
+		if (new == PCI_ERS_RESULT_NEED_RESET)
+			orig = PCI_ERS_RESULT_NEED_RESET;
+		break;
+	default:
+		break;
+	}
+
+	return orig;
+}
+
+static int report_error_detected(struct pci_dev *dev,
+				 pci_channel_state_t state,
+				 enum pci_ers_result *result)
+{
+	struct pci_driver *pdrv;
+	pci_ers_result_t vote;
+	const struct pci_error_handlers *err_handler;
+
+	device_lock(&dev->dev);
+	pdrv = dev->driver;
+	if (pci_dev_is_disconnected(dev)) {
+		vote = PCI_ERS_RESULT_DISCONNECT;
+	} else if (!pci_dev_set_io_state(dev, state)) {
+		pci_info(dev, "can't recover (state transition %u -> %u invalid)\n",
+			dev->error_state, state);
+		vote = PCI_ERS_RESULT_NONE;
+	} else if (!pdrv || !pdrv->err_handler ||
+		   !pdrv->err_handler->error_detected) {
+		/*
+		 * If any device in the subtree does not have an error_detected
+		 * callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent
+		 * error callbacks of "any" device in the subtree, and will
+		 * exit in the disconnected error state.
+		 */
+		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
+			vote = PCI_ERS_RESULT_NO_AER_DRIVER;
+			pci_info(dev, "can't recover (no error_detected callback)\n");
+		} else {
+			vote = PCI_ERS_RESULT_NONE;
+		}
+	} else {
+		err_handler = pdrv->err_handler;
+		vote = err_handler->error_detected(dev, state);
+	}
+	pci_uevent_ers(dev, vote);
+	*result = merge_result(*result, vote);
+	device_unlock(&dev->dev);
+	return 0;
+}
+
+static int report_frozen_detected(struct pci_dev *dev, void *data)
+{
+	return report_error_detected(dev, pci_channel_io_frozen, data);
+}
+
+static int report_normal_detected(struct pci_dev *dev, void *data)
+{
+	return report_error_detected(dev, pci_channel_io_normal, data);
+}
+
+static int report_mmio_enabled(struct pci_dev *dev, void *data)
+{
+	struct pci_driver *pdrv;
+	pci_ers_result_t vote, *result = data;
+	const struct pci_error_handlers *err_handler;
+
+	device_lock(&dev->dev);
+	pdrv = dev->driver;
+	if (!pdrv ||
+		!pdrv->err_handler ||
+		!pdrv->err_handler->mmio_enabled)
+		goto out;
+
+	err_handler = pdrv->err_handler;
+	vote = err_handler->mmio_enabled(dev);
+	*result = merge_result(*result, vote);
+out:
+	device_unlock(&dev->dev);
+	return 0;
+}
+
+static int report_slot_reset(struct pci_dev *dev, void *data)
+{
+	struct pci_driver *pdrv;
+	pci_ers_result_t vote, *result = data;
+	const struct pci_error_handlers *err_handler;
+
+	device_lock(&dev->dev);
+	pdrv = dev->driver;
+	if (!pdrv ||
+		!pdrv->err_handler ||
+		!pdrv->err_handler->slot_reset)
+		goto out;
+
+	err_handler = pdrv->err_handler;
+	vote = err_handler->slot_reset(dev);
+	*result = merge_result(*result, vote);
+out:
+	device_unlock(&dev->dev);
+	return 0;
+}
+
+static int report_resume(struct pci_dev *dev, void *data)
+{
+	struct pci_driver *pdrv;
+	const struct pci_error_handlers *err_handler;
+
+	device_lock(&dev->dev);
+	pdrv = dev->driver;
+	if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
+		!pdrv ||
+		!pdrv->err_handler ||
+		!pdrv->err_handler->resume)
+		goto out;
+
+	err_handler = pdrv->err_handler;
+	err_handler->resume(dev);
+out:
+	pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
+	device_unlock(&dev->dev);
+	return 0;
+}
+
+/**
+ * pci_walk_bridge - walk bridges potentially AER affected
+ * @bridge:	bridge which may be a Port, an RCEC, or an RCiEP
+ * @cb:		callback to be called for each device found
+ * @userdata:	arbitrary pointer to be passed to callback
+ *
+ * If the device provided is a bridge, walk the subordinate bus, including
+ * any bridged devices on buses under this bus.  Call the provided callback
+ * on each device found.
+ *
+ * If the device provided has no subordinate bus, e.g., an RCEC or RCiEP,
+ * call the callback on the device itself.
+ */
+static void pci_walk_bridge(struct pci_dev *bridge,
+			    int (*cb)(struct pci_dev *, void *),
+			    void *userdata)
+{
+	if (bridge->subordinate)
+		pci_walk_bus(bridge->subordinate, cb, userdata);
+	else
+		cb(bridge, userdata);
+}
+
+pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
+		pci_channel_state_t state,
+		pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev))
+{
+	int type = pci_pcie_type(dev);
+	struct pci_dev *bridge;
+	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
+	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
+
+	/*
+	 * If the error was detected by a Root Port, Downstream Port, RCEC,
+	 * or RCiEP, recovery runs on the device itself.  For Ports, that
+	 * also includes any subordinate devices.
+	 *
+	 * If it was detected by another device (Endpoint, etc), recovery
+	 * runs on the device and anything else under the same Port, i.e.,
+	 * everything under "bridge".
+	 */
+	if (type == PCI_EXP_TYPE_ROOT_PORT ||
+	    type == PCI_EXP_TYPE_DOWNSTREAM ||
+	    type == PCI_EXP_TYPE_RC_EC ||
+	    type == PCI_EXP_TYPE_RC_END)
+		bridge = dev;
+	else
+		bridge = pci_upstream_bridge(dev);
+
+	pci_dbg(bridge, "broadcast error_detected message\n");
+	if (state == pci_channel_io_frozen) {
+		pci_walk_bridge(bridge, report_frozen_detected, &status);
+		if (reset_subordinates(bridge) != PCI_ERS_RESULT_RECOVERED) {
+			pci_warn(bridge, "subordinate device reset failed\n");
+			goto failed;
+		}
+	} else {
+		pci_walk_bridge(bridge, report_normal_detected, &status);
+	}
+
+	if (status == PCI_ERS_RESULT_CAN_RECOVER) {
+		status = PCI_ERS_RESULT_RECOVERED;
+		pci_dbg(bridge, "broadcast mmio_enabled message\n");
+		pci_walk_bridge(bridge, report_mmio_enabled, &status);
+	}
+
+	if (status == PCI_ERS_RESULT_NEED_RESET) {
+		/*
+		 * TODO: Should call platform-specific
+		 * functions to reset slot before calling
+		 * drivers' slot_reset callbacks?
+		 */
+		status = PCI_ERS_RESULT_RECOVERED;
+		pci_dbg(bridge, "broadcast slot_reset message\n");
+		pci_walk_bridge(bridge, report_slot_reset, &status);
+	}
+
+	if (status != PCI_ERS_RESULT_RECOVERED)
+		goto failed;
+
+	pci_dbg(bridge, "broadcast resume message\n");
+	pci_walk_bridge(bridge, report_resume, &status);
+
+	/*
+	 * If we have native control of AER, clear error status in the device
+	 * that detected the error.  If the platform retained control of AER,
+	 * it is responsible for clearing this status.  In that case, the
+	 * signaling device may not even be visible to the OS.
+	 */
+	if (host->native_aer || pcie_ports_native) {
+		pcie_clear_device_status(dev);
+		pci_aer_clear_nonfatal_status(dev);
+	}
+	pci_info(bridge, "device recovery successful\n");
+	return status;
+
+failed:
+	pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT);
+
+	/* TODO: Should kernel panic here? */
+	pci_info(bridge, "device recovery failed\n");
+
+	return status;
+}