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