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// 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)
*/
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/aer.h>
#include "portdrv.h"
#include "../pci.h"
struct aer_broadcast_data {
enum pci_channel_state state;
enum pci_ers_result result;
};
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, void *data)
{
pci_ers_result_t vote;
const struct pci_error_handlers *err_handler;
struct aer_broadcast_data *result_data;
result_data = (struct aer_broadcast_data *) data;
device_lock(&dev->dev);
dev->error_state = result_data->state;
if (!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->err_handler->error_detected) {
if (result_data->state == pci_channel_io_frozen &&
dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
/*
* In case of fatal recovery, if one of down-
* stream device has no driver. We might be
* unable to recover because a later insmod
* of a driver for this device is unaware of
* its hw state.
*/
pci_printk(KERN_DEBUG, dev, "device has %s\n",
dev->driver ?
"no AER-aware driver" : "no driver");
}
/*
* If there's any device in the subtree that does not
* have an error_detected callback, returning
* PCI_ERS_RESULT_NO_AER_DRIVER prevents calling of
* the subsequent mmio_enabled/slot_reset/resume
* callbacks of "any" device in the subtree. All the
* devices in the subtree are left in the error state
* without recovery.
*/
if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
vote = PCI_ERS_RESULT_NO_AER_DRIVER;
else
vote = PCI_ERS_RESULT_NONE;
} else {
err_handler = dev->driver->err_handler;
vote = err_handler->error_detected(dev, result_data->state);
pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
}
result_data->result = merge_result(result_data->result, vote);
device_unlock(&dev->dev);
return 0;
}
static int report_mmio_enabled(struct pci_dev *dev, void *data)
{
pci_ers_result_t vote;
const struct pci_error_handlers *err_handler;
struct aer_broadcast_data *result_data;
result_data = (struct aer_broadcast_data *) data;
device_lock(&dev->dev);
if (!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->err_handler->mmio_enabled)
goto out;
err_handler = dev->driver->err_handler;
vote = err_handler->mmio_enabled(dev);
result_data->result = merge_result(result_data->result, vote);
out:
device_unlock(&dev->dev);
return 0;
}
static int report_slot_reset(struct pci_dev *dev, void *data)
{
pci_ers_result_t vote;
const struct pci_error_handlers *err_handler;
struct aer_broadcast_data *result_data;
result_data = (struct aer_broadcast_data *) data;
device_lock(&dev->dev);
if (!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->err_handler->slot_reset)
goto out;
err_handler = dev->driver->err_handler;
vote = err_handler->slot_reset(dev);
result_data->result = merge_result(result_data->result, vote);
out:
device_unlock(&dev->dev);
return 0;
}
static int report_resume(struct pci_dev *dev, void *data)
{
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
dev->error_state = pci_channel_io_normal;
if (!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->err_handler->resume)
goto out;
err_handler = dev->driver->err_handler;
err_handler->resume(dev);
pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
out:
device_unlock(&dev->dev);
return 0;
}
/**
* default_reset_link - default reset function
* @dev: pointer to pci_dev data structure
*
* Invoked when performing link reset on a Downstream Port or a
* Root Port with no aer driver.
*/
static pci_ers_result_t default_reset_link(struct pci_dev *dev)
{
int rc;
rc = pci_bridge_secondary_bus_reset(dev);
pci_printk(KERN_DEBUG, dev, "downstream link has been reset\n");
return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
}
static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
{
struct pci_dev *udev;
pci_ers_result_t status;
struct pcie_port_service_driver *driver = NULL;
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
/* Reset this port for all subordinates */
udev = dev;
} else {
/* Reset the upstream component (likely downstream port) */
udev = dev->bus->self;
}
/* Use the aer driver of the component firstly */
driver = pcie_port_find_service(udev, service);
if (driver && driver->reset_link) {
status = driver->reset_link(udev);
} else if (udev->has_secondary_link) {
status = default_reset_link(udev);
} else {
pci_printk(KERN_DEBUG, dev, "no link-reset support at upstream device %s\n",
pci_name(udev));
return PCI_ERS_RESULT_DISCONNECT;
}
if (status != PCI_ERS_RESULT_RECOVERED) {
pci_printk(KERN_DEBUG, dev, "link reset at upstream device %s failed\n",
pci_name(udev));
return PCI_ERS_RESULT_DISCONNECT;
}
return status;
}
/**
* broadcast_error_message - handle message broadcast to downstream drivers
* @dev: pointer to from where in a hierarchy message is broadcasted down
* @state: error state
* @error_mesg: message to print
* @cb: callback to be broadcasted
*
* Invoked during error recovery process. Once being invoked, the content
* of error severity will be broadcasted to all downstream drivers in a
* hierarchy in question.
*/
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 *))
{
struct aer_broadcast_data result_data;
pci_printk(KERN_DEBUG, dev, "broadcast %s message\n", error_mesg);
result_data.state = state;
if (cb == report_error_detected)
result_data.result = PCI_ERS_RESULT_CAN_RECOVER;
else
result_data.result = PCI_ERS_RESULT_RECOVERED;
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
/*
* If the error is reported by a bridge, we think this error
* is related to the downstream link of the bridge, so we
* do error recovery on all subordinates of the bridge instead
* of the bridge and clear the error status of the bridge.
*/
if (cb == report_error_detected)
dev->error_state = state;
pci_walk_bus(dev->subordinate, cb, &result_data);
if (cb == report_resume) {
pci_aer_clear_device_status(dev);
pci_cleanup_aer_uncorrect_error_status(dev);
dev->error_state = pci_channel_io_normal;
}
} else {
/*
* If the error is reported by an end point, we think this
* error is related to the upstream link of the end point.
* The error is non fatal so the bus is ok; just invoke
* the callback for the function that logged the error.
*/
cb(dev, &result_data);
}
return result_data.result;
}
/**
* pcie_do_fatal_recovery - handle fatal error recovery process
* @dev: pointer to a pci_dev data structure of agent detecting an error
*
* Invoked when an error is fatal. Once being invoked, removes the devices
* beneath this AER agent, followed by reset link e.g. secondary bus reset
* followed by re-enumeration of devices.
*/
void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service)
{
struct pci_dev *udev;
struct pci_bus *parent;
struct pci_dev *pdev, *temp;
pci_ers_result_t result;
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
udev = dev;
else
udev = dev->bus->self;
parent = udev->subordinate;
pci_lock_rescan_remove();
pci_dev_get(dev);
list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
bus_list) {
pci_dev_get(pdev);
pci_dev_set_disconnected(pdev, NULL);
if (pci_has_subordinate(pdev))
pci_walk_bus(pdev->subordinate,
pci_dev_set_disconnected, NULL);
pci_stop_and_remove_bus_device(pdev);
pci_dev_put(pdev);
}
result = reset_link(udev, service);
if ((service == PCIE_PORT_SERVICE_AER) &&
(dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
/*
* If the error is reported by a bridge, we think this error
* is related to the downstream link of the bridge, so we
* do error recovery on all subordinates of the bridge instead
* of the bridge and clear the error status of the bridge.
*/
pci_aer_clear_fatal_status(dev);
pci_aer_clear_device_status(dev);
}
if (result == PCI_ERS_RESULT_RECOVERED) {
if (pcie_wait_for_link(udev, true))
pci_rescan_bus(udev->bus);
pci_info(dev, "Device recovery from fatal error successful\n");
} else {
pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
pci_info(dev, "Device recovery from fatal error failed\n");
}
pci_dev_put(dev);
pci_unlock_rescan_remove();
}
/**
* pcie_do_nonfatal_recovery - handle nonfatal error recovery process
* @dev: pointer to a pci_dev data structure of agent detecting an error
*
* Invoked when an error is nonfatal/fatal. Once being invoked, broadcast
* error detected message to all downstream drivers within a hierarchy in
* question and return the returned code.
*/
void pcie_do_nonfatal_recovery(struct pci_dev *dev)
{
pci_ers_result_t status;
enum pci_channel_state state;
state = pci_channel_io_normal;
status = broadcast_error_message(dev,
state,
"error_detected",
report_error_detected);
if (status == PCI_ERS_RESULT_CAN_RECOVER)
status = broadcast_error_message(dev,
state,
"mmio_enabled",
report_mmio_enabled);
if (status == PCI_ERS_RESULT_NEED_RESET) {
/*
* TODO: Should call platform-specific
* functions to reset slot before calling
* drivers' slot_reset callbacks?
*/
status = broadcast_error_message(dev,
state,
"slot_reset",
report_slot_reset);
}
if (status != PCI_ERS_RESULT_RECOVERED)
goto failed;
broadcast_error_message(dev,
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");
}