2018-05-18 00:44:15 +03:00
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// 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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#include <linux/pci.h>
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#include <linux/module.h>
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#include <linux/pci.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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struct aer_broadcast_data {
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enum pci_channel_state state;
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enum pci_ers_result result;
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};
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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, void *data)
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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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struct aer_broadcast_data *result_data;
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result_data = (struct aer_broadcast_data *) data;
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device_lock(&dev->dev);
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dev->error_state = result_data->state;
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if (!dev->driver ||
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!dev->driver->err_handler ||
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!dev->driver->err_handler->error_detected) {
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if (result_data->state == pci_channel_io_frozen &&
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dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
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/*
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* In case of fatal recovery, if one of down-
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* stream device has no driver. We might be
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* unable to recover because a later insmod
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* of a driver for this device is unaware of
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* its hw state.
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*/
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pci_printk(KERN_DEBUG, dev, "device has %s\n",
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dev->driver ?
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"no AER-aware driver" : "no driver");
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}
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/*
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* If there's any device in the subtree that does not
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* have an error_detected callback, returning
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* PCI_ERS_RESULT_NO_AER_DRIVER prevents calling of
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* the subsequent mmio_enabled/slot_reset/resume
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* callbacks of "any" device in the subtree. All the
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* devices in the subtree are left in the error state
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* without recovery.
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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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else
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vote = PCI_ERS_RESULT_NONE;
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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, result_data->state);
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pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
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}
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result_data->result = merge_result(result_data->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_mmio_enabled(struct pci_dev *dev, void *data)
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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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struct aer_broadcast_data *result_data;
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result_data = (struct aer_broadcast_data *) data;
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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_data->result = merge_result(result_data->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;
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const struct pci_error_handlers *err_handler;
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struct aer_broadcast_data *result_data;
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result_data = (struct aer_broadcast_data *) data;
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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_data->result = merge_result(result_data->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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dev->error_state = pci_channel_io_normal;
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if (!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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pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
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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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/**
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* default_reset_link - default reset function
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* @dev: pointer to pci_dev data structure
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*
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* Invoked when performing link reset on a Downstream Port or a
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* Root Port with no aer driver.
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*/
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static pci_ers_result_t default_reset_link(struct pci_dev *dev)
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{
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pci_reset_bridge_secondary_bus(dev);
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pci_printk(KERN_DEBUG, dev, "downstream link has been reset\n");
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return PCI_ERS_RESULT_RECOVERED;
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}
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static pci_ers_result_t reset_link(struct pci_dev *dev)
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{
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struct pci_dev *udev;
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pci_ers_result_t status;
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struct pcie_port_service_driver *driver = NULL;
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if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
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/* Reset this port for all subordinates */
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udev = dev;
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} else {
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/* Reset the upstream component (likely downstream port) */
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udev = dev->bus->self;
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}
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/* Use the aer driver of the component firstly */
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2018-05-18 00:44:16 +03:00
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driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
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2018-05-18 00:44:15 +03:00
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if (driver && driver->reset_link) {
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status = driver->reset_link(udev);
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} else if (udev->has_secondary_link) {
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status = default_reset_link(udev);
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} else {
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pci_printk(KERN_DEBUG, dev, "no link-reset support at upstream device %s\n",
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pci_name(udev));
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return PCI_ERS_RESULT_DISCONNECT;
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}
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if (status != PCI_ERS_RESULT_RECOVERED) {
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pci_printk(KERN_DEBUG, dev, "link reset at upstream device %s failed\n",
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pci_name(udev));
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return PCI_ERS_RESULT_DISCONNECT;
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}
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return status;
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}
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/**
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* broadcast_error_message - handle message broadcast to downstream drivers
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* @dev: pointer to from where in a hierarchy message is broadcasted down
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* @state: error state
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* @error_mesg: message to print
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* @cb: callback to be broadcasted
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*
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* Invoked during error recovery process. Once being invoked, the content
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* of error severity will be broadcasted to all downstream drivers in a
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* hierarchy in question.
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*/
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static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
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enum pci_channel_state state,
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char *error_mesg,
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int (*cb)(struct pci_dev *, void *))
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{
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struct aer_broadcast_data result_data;
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pci_printk(KERN_DEBUG, dev, "broadcast %s message\n", error_mesg);
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result_data.state = state;
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if (cb == report_error_detected)
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result_data.result = PCI_ERS_RESULT_CAN_RECOVER;
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else
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result_data.result = PCI_ERS_RESULT_RECOVERED;
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if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
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/*
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* If the error is reported by a bridge, we think this error
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* is related to the downstream link of the bridge, so we
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* do error recovery on all subordinates of the bridge instead
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* of the bridge and clear the error status of the bridge.
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*/
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if (cb == report_error_detected)
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dev->error_state = state;
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pci_walk_bus(dev->subordinate, cb, &result_data);
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if (cb == report_resume) {
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pci_cleanup_aer_uncorrect_error_status(dev);
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dev->error_state = pci_channel_io_normal;
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}
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} else {
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/*
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* If the error is reported by an end point, we think this
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* error is related to the upstream link of the end point.
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*/
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if (state == pci_channel_io_normal)
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/*
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* the error is non fatal so the bus is ok, just invoke
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* the callback for the function that logged the error.
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*/
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cb(dev, &result_data);
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else
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pci_walk_bus(dev->bus, cb, &result_data);
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}
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return result_data.result;
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}
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/**
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* pcie_do_fatal_recovery - handle fatal error recovery process
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* @dev: pointer to a pci_dev data structure of agent detecting an error
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*
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* Invoked when an error is fatal. Once being invoked, removes the devices
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* beneath this AER agent, followed by reset link e.g. secondary bus reset
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* followed by re-enumeration of devices.
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*/
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void pcie_do_fatal_recovery(struct pci_dev *dev)
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{
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struct pci_dev *udev;
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struct pci_bus *parent;
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struct pci_dev *pdev, *temp;
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pci_ers_result_t result;
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if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
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udev = dev;
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else
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udev = dev->bus->self;
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parent = udev->subordinate;
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pci_lock_rescan_remove();
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list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
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bus_list) {
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pci_dev_get(pdev);
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pci_dev_set_disconnected(pdev, NULL);
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if (pci_has_subordinate(pdev))
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pci_walk_bus(pdev->subordinate,
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pci_dev_set_disconnected, NULL);
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pci_stop_and_remove_bus_device(pdev);
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pci_dev_put(pdev);
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}
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result = reset_link(udev);
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if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
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/*
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* If the error is reported by a bridge, we think this error
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* is related to the downstream link of the bridge, so we
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* do error recovery on all subordinates of the bridge instead
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* of the bridge and clear the error status of the bridge.
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*/
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pci_cleanup_aer_uncorrect_error_status(dev);
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}
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if (result == PCI_ERS_RESULT_RECOVERED) {
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if (pcie_wait_for_link(udev, true))
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pci_rescan_bus(udev->bus);
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pci_info(dev, "Device recovery from fatal error successful\n");
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} else {
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pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
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pci_info(dev, "Device recovery from fatal error failed\n");
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}
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pci_unlock_rescan_remove();
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}
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/**
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* pcie_do_nonfatal_recovery - handle nonfatal error recovery process
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* @dev: pointer to a pci_dev data structure of agent detecting an error
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*
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* Invoked when an error is nonfatal/fatal. Once being invoked, broadcast
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* error detected message to all downstream drivers within a hierarchy in
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* question and return the returned code.
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*/
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void pcie_do_nonfatal_recovery(struct pci_dev *dev)
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{
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pci_ers_result_t status;
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enum pci_channel_state state;
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state = pci_channel_io_normal;
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status = broadcast_error_message(dev,
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state,
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"error_detected",
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report_error_detected);
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if (status == PCI_ERS_RESULT_CAN_RECOVER)
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status = broadcast_error_message(dev,
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state,
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"mmio_enabled",
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report_mmio_enabled);
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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 = broadcast_error_message(dev,
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state,
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"slot_reset",
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report_slot_reset);
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}
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if (status != PCI_ERS_RESULT_RECOVERED)
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goto failed;
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broadcast_error_message(dev,
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state,
|
|
|
|
"resume",
|
|
|
|
report_resume);
|
|
|
|
|
|
|
|
pci_info(dev, "AER: Device recovery successful\n");
|
|
|
|
return;
|
|
|
|
|
|
|
|
failed:
|
|
|
|
pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
|
|
|
|
|
|
|
|
/* TODO: Should kernel panic here? */
|
|
|
|
pci_info(dev, "AER: Device recovery failed\n");
|
|
|
|
}
|