drivers/pci/pcie/err.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file implements the error recovery as a core part of PCIe error
   4  * reporting. When a PCIe error is delivered, an error message will be
   5  * collected and printed to console, then, an error recovery procedure
   6  * will be executed by following the PCI error recovery rules.
   7  *
   8  * Copyright (C) 2006 Intel Corp.
   9  *      Tom Long Nguyen (tom.l.nguyen@intel.com)
  10  *      Zhang Yanmin (yanmin.zhang@intel.com)
  11  */
  12
  13 #define dev_fmt(fmt) "AER: " fmt
  14
  15 #include <linux/pci.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/errno.h>
  19 #include <linux/aer.h>
  20 #include "portdrv.h"
  21 #include "../pci.h"
  22
  23 static pci_ers_result_t merge_result(enum pci_ers_result orig,
  24                                   enum pci_ers_result new)
  25 {
  26         if (new == PCI_ERS_RESULT_NO_AER_DRIVER)
  27                 return PCI_ERS_RESULT_NO_AER_DRIVER;
  28
  29         if (new == PCI_ERS_RESULT_NONE)
  30                 return orig;
  31
  32         switch (orig) {
  33         case PCI_ERS_RESULT_CAN_RECOVER:
  34         case PCI_ERS_RESULT_RECOVERED:
  35                 orig = new;
  36                 break;
  37         case PCI_ERS_RESULT_DISCONNECT:
  38                 if (new == PCI_ERS_RESULT_NEED_RESET)
  39                         orig = PCI_ERS_RESULT_NEED_RESET;
  40                 break;
  41         default:
  42                 break;
  43         }
  44
  45         return orig;
  46 }
  47
  48 static int report_error_detected(struct pci_dev *dev,
  49                                  pci_channel_state_t state,
  50                                  enum pci_ers_result *result)
  51 {
  52         pci_ers_result_t vote;
  53         const struct pci_error_handlers *err_handler;
  54
  55         device_lock(&dev->dev);
  56         if (!pci_dev_set_io_state(dev, state) ||
  57                 !dev->driver ||
  58                 !dev->driver->err_handler ||
  59                 !dev->driver->err_handler->error_detected) {
  60                 /*
  61                  * If any device in the subtree does not have an error_detected
  62                  * callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent
  63                  * error callbacks of "any" device in the subtree, and will
  64                  * exit in the disconnected error state.
  65                  */
  66                 if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
  67                         vote = PCI_ERS_RESULT_NO_AER_DRIVER;
  68                         pci_info(dev, "can't recover (no error_detected callback)\n");
  69                 } else {
  70                         vote = PCI_ERS_RESULT_NONE;
  71                 }
  72         } else {
  73                 err_handler = dev->driver->err_handler;
  74                 vote = err_handler->error_detected(dev, state);
  75         }
  76         pci_uevent_ers(dev, vote);
  77         *result = merge_result(*result, vote);
  78         device_unlock(&dev->dev);
  79         return 0;
  80 }
  81
  82 static int report_frozen_detected(struct pci_dev *dev, void *data)
  83 {
  84         return report_error_detected(dev, pci_channel_io_frozen, data);
  85 }
  86
  87 static int report_normal_detected(struct pci_dev *dev, void *data)
  88 {
  89         return report_error_detected(dev, pci_channel_io_normal, data);
  90 }
  91
  92 static int report_mmio_enabled(struct pci_dev *dev, void *data)
  93 {
  94         pci_ers_result_t vote, *result = data;
  95         const struct pci_error_handlers *err_handler;
  96
  97         device_lock(&dev->dev);
  98         if (!dev->driver ||
  99                 !dev->driver->err_handler ||
 100                 !dev->driver->err_handler->mmio_enabled)
 101                 goto out;
 102
 103         err_handler = dev->driver->err_handler;
 104         vote = err_handler->mmio_enabled(dev);
 105         *result = merge_result(*result, vote);
 106 out:
 107         device_unlock(&dev->dev);
 108         return 0;
 109 }
 110
 111 static int report_slot_reset(struct pci_dev *dev, void *data)
 112 {
 113         pci_ers_result_t vote, *result = data;
 114         const struct pci_error_handlers *err_handler;
 115
 116         device_lock(&dev->dev);
 117         if (!dev->driver ||
 118                 !dev->driver->err_handler ||
 119                 !dev->driver->err_handler->slot_reset)
 120                 goto out;
 121
 122         err_handler = dev->driver->err_handler;
 123         vote = err_handler->slot_reset(dev);
 124         *result = merge_result(*result, vote);
 125 out:
 126         device_unlock(&dev->dev);
 127         return 0;
 128 }
 129
 130 static int report_resume(struct pci_dev *dev, void *data)
 131 {
 132         const struct pci_error_handlers *err_handler;
 133
 134         device_lock(&dev->dev);
 135         if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
 136                 !dev->driver ||
 137                 !dev->driver->err_handler ||
 138                 !dev->driver->err_handler->resume)
 139                 goto out;
 140
 141         err_handler = dev->driver->err_handler;
 142         err_handler->resume(dev);
 143 out:
 144         pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
 145         device_unlock(&dev->dev);
 146         return 0;
 147 }
 148
 149 /**
 150  * pci_walk_bridge - walk bridges potentially AER affected
 151  * @bridge:     bridge which may be a Port, an RCEC, or an RCiEP
 152  * @cb:         callback to be called for each device found
 153  * @userdata:   arbitrary pointer to be passed to callback
 154  *
 155  * If the device provided is a bridge, walk the subordinate bus, including
 156  * any bridged devices on buses under this bus.  Call the provided callback
 157  * on each device found.
 158  *
 159  * If the device provided has no subordinate bus, e.g., an RCEC or RCiEP,
 160  * call the callback on the device itself.
 161  */
 162 static void pci_walk_bridge(struct pci_dev *bridge,
 163                             int (*cb)(struct pci_dev *, void *),
 164                             void *userdata)
 165 {
 166         if (bridge->subordinate)
 167                 pci_walk_bus(bridge->subordinate, cb, userdata);
 168         else
 169                 cb(bridge, userdata);
 170 }
 171
 172 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 173                 pci_channel_state_t state,
 174                 pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev))
 175 {
 176         int type = pci_pcie_type(dev);
 177         struct pci_dev *bridge;
 178         pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
 179         struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 180
 181         /*
 182          * If the error was detected by a Root Port, Downstream Port, RCEC,
 183          * or RCiEP, recovery runs on the device itself.  For Ports, that
 184          * also includes any subordinate devices.
 185          *
 186          * If it was detected by another device (Endpoint, etc), recovery
 187          * runs on the device and anything else under the same Port, i.e.,
 188          * everything under "bridge".
 189          */
 190         if (type == PCI_EXP_TYPE_ROOT_PORT ||
 191             type == PCI_EXP_TYPE_DOWNSTREAM ||
 192             type == PCI_EXP_TYPE_RC_EC ||
 193             type == PCI_EXP_TYPE_RC_END)
 194                 bridge = dev;
 195         else
 196                 bridge = pci_upstream_bridge(dev);
 197
 198         pci_dbg(bridge, "broadcast error_detected message\n");
 199         if (state == pci_channel_io_frozen) {
 200                 pci_walk_bridge(bridge, report_frozen_detected, &status);
 201                 if (reset_subordinates(bridge) != PCI_ERS_RESULT_RECOVERED) {
 202                         pci_warn(bridge, "subordinate device reset failed\n");
 203                         goto failed;
 204                 }
 205         } else {
 206                 pci_walk_bridge(bridge, report_normal_detected, &status);
 207         }
 208
 209         if (status == PCI_ERS_RESULT_CAN_RECOVER) {
 210                 status = PCI_ERS_RESULT_RECOVERED;
 211                 pci_dbg(bridge, "broadcast mmio_enabled message\n");
 212                 pci_walk_bridge(bridge, report_mmio_enabled, &status);
 213         }
 214
 215         if (status == PCI_ERS_RESULT_NEED_RESET) {
 216                 /*
 217                  * TODO: Should call platform-specific
 218                  * functions to reset slot before calling
 219                  * drivers' slot_reset callbacks?
 220                  */
 221                 status = PCI_ERS_RESULT_RECOVERED;
 222                 pci_dbg(bridge, "broadcast slot_reset message\n");
 223                 pci_walk_bridge(bridge, report_slot_reset, &status);
 224         }
 225
 226         if (status != PCI_ERS_RESULT_RECOVERED)
 227                 goto failed;
 228
 229         pci_dbg(bridge, "broadcast resume message\n");
 230         pci_walk_bridge(bridge, report_resume, &status);
 231
 232         /*
 233          * If we have native control of AER, clear error status in the device
 234          * that detected the error.  If the platform retained control of AER,
 235          * it is responsible for clearing this status.  In that case, the
 236          * signaling device may not even be visible to the OS.
 237          */
 238         if (host->native_aer || pcie_ports_native) {
 239                 pcie_clear_device_status(dev);
 240                 pci_aer_clear_nonfatal_status(dev);
 241         }
 242         pci_info(bridge, "device recovery successful\n");
 243         return status;
 244
 245 failed:
 246         pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT);
 247
 248         /* TODO: Should kernel panic here? */
 249         pci_info(bridge, "device recovery failed\n");
 250
 251         return status;
 252 }