diff options
Diffstat (limited to 'drivers/pci/pcie/err.c')
| -rw-r--r-- | drivers/pci/pcie/err.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c new file mode 100644 index 000000000000..f7ce0cb0b0b7 --- /dev/null +++ b/drivers/pci/pcie/err.c @@ -0,0 +1,388 @@ +// 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) +{ + pci_reset_bridge_secondary_bus(dev); + pci_printk(KERN_DEBUG, dev, "downstream link has been reset\n"); + return 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_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. + */ + if (state == pci_channel_io_normal) + /* + * 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); + else + pci_walk_bus(dev->bus, cb, &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(); + 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_cleanup_aer_uncorrect_error_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_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"); +} |