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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)
*/
#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,
enum pci_channel_state state,
enum pci_ers_result *result)
{
pci_ers_result_t vote;
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
if (!pci_dev_set_io_state(dev, state) ||
!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->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 = dev->driver->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)
{
pci_ers_result_t vote, *result = data;
const struct pci_error_handlers *err_handler;
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 = merge_result(*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, *result = data;
const struct pci_error_handlers *err_handler;
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 = merge_result(*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);
if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
!dev->driver ||
!dev->driver->err_handler ||
!dev->driver->err_handler->resume)
goto out;
err_handler = dev->driver->err_handler;
err_handler->resume(dev);
out:
pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
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_bus_error_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)
{
pci_ers_result_t status;
struct pcie_port_service_driver *driver = NULL;
driver = pcie_port_find_service(dev, service);
if (driver && driver->reset_link) {
status = driver->reset_link(dev);
} else if (pcie_downstream_port(dev)) {
status = default_reset_link(dev);
} else {
pci_printk(KERN_DEBUG, dev, "no link-reset support at upstream device %s\n",
pci_name(dev));
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(dev));
return PCI_ERS_RESULT_DISCONNECT;
}
return status;
}
void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
u32 service)
{
pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
struct pci_bus *bus;
/*
* Error recovery runs on all subordinates of the first downstream port.
* If the downstream port detected the error, it is cleared at the end.
*/
if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM))
dev = dev->bus->self;
bus = dev->subordinate;
pci_dbg(dev, "broadcast error_detected message\n");
if (state == pci_channel_io_frozen)
pci_walk_bus(bus, report_frozen_detected, &status);
else
pci_walk_bus(bus, report_normal_detected, &status);
if (state == pci_channel_io_frozen &&
reset_link(dev, service) != PCI_ERS_RESULT_RECOVERED)
goto failed;
if (status == PCI_ERS_RESULT_CAN_RECOVER) {
status = PCI_ERS_RESULT_RECOVERED;
pci_dbg(dev, "broadcast mmio_enabled message\n");
pci_walk_bus(bus, 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(dev, "broadcast slot_reset message\n");
pci_walk_bus(bus, report_slot_reset, &status);
}
if (status != PCI_ERS_RESULT_RECOVERED)
goto failed;
pci_dbg(dev, "broadcast resume message\n");
pci_walk_bus(bus, report_resume, &status);
pci_aer_clear_device_status(dev);
pci_cleanup_aer_uncorrect_error_status(dev);
pci_info(dev, "device recovery successful\n");
return;
failed:
pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
/* TODO: Should kernel panic here? */
pci_info(dev, "device recovery failed\n");
}
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