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/pm_runtime.h> 17 #include <linux/module.h> 18 #include <linux/kernel.h> 19 #include <linux/errno.h> 20 #include <linux/aer.h> 21 #include "portdrv.h" 22 #include "../pci.h" 23 24 static pci_ers_result_t merge_result(enum pci_ers_result orig, 25 enum pci_ers_result new) 26 { 27 if (new == PCI_ERS_RESULT_NO_AER_DRIVER) 28 return PCI_ERS_RESULT_NO_AER_DRIVER; 29 30 if (new == PCI_ERS_RESULT_NONE) 31 return orig; 32 33 switch (orig) { 34 case PCI_ERS_RESULT_CAN_RECOVER: 35 case PCI_ERS_RESULT_RECOVERED: 36 orig = new; 37 break; 38 case PCI_ERS_RESULT_DISCONNECT: 39 if (new == PCI_ERS_RESULT_NEED_RESET) 40 orig = PCI_ERS_RESULT_NEED_RESET; 41 break; 42 default: 43 break; 44 } 45 46 return orig; 47 } 48 49 static int report_error_detected(struct pci_dev *dev, 50 pci_channel_state_t state, 51 enum pci_ers_result *result) 52 { 53 struct pci_driver *pdrv; 54 pci_ers_result_t vote; 55 const struct pci_error_handlers *err_handler; 56 57 device_lock(&dev->dev); 58 pdrv = dev->driver; 59 if (pci_dev_is_disconnected(dev)) { 60 vote = PCI_ERS_RESULT_DISCONNECT; 61 } else if (!pci_dev_set_io_state(dev, state)) { 62 pci_info(dev, "can't recover (state transition %u -> %u invalid)\n", 63 dev->error_state, state); 64 vote = PCI_ERS_RESULT_NONE; 65 } else if (!pdrv || !pdrv->err_handler || 66 !pdrv->err_handler->error_detected) { 67 /* 68 * If any device in the subtree does not have an error_detected 69 * callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent 70 * error callbacks of "any" device in the subtree, and will 71 * exit in the disconnected error state. 72 */ 73 if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) { 74 vote = PCI_ERS_RESULT_NO_AER_DRIVER; 75 pci_info(dev, "can't recover (no error_detected callback)\n"); 76 } else { 77 vote = PCI_ERS_RESULT_NONE; 78 } 79 } else { 80 err_handler = pdrv->err_handler; 81 vote = err_handler->error_detected(dev, state); 82 } 83 pci_uevent_ers(dev, vote); 84 *result = merge_result(*result, vote); 85 device_unlock(&dev->dev); 86 return 0; 87 } 88 89 static int pci_pm_runtime_get_sync(struct pci_dev *pdev, void *data) 90 { 91 pm_runtime_get_sync(&pdev->dev); 92 return 0; 93 } 94 95 static int pci_pm_runtime_put(struct pci_dev *pdev, void *data) 96 { 97 pm_runtime_put(&pdev->dev); 98 return 0; 99 } 100 101 static int report_frozen_detected(struct pci_dev *dev, void *data) 102 { 103 return report_error_detected(dev, pci_channel_io_frozen, data); 104 } 105 106 static int report_normal_detected(struct pci_dev *dev, void *data) 107 { 108 return report_error_detected(dev, pci_channel_io_normal, data); 109 } 110 111 static int report_mmio_enabled(struct pci_dev *dev, void *data) 112 { 113 struct pci_driver *pdrv; 114 pci_ers_result_t vote, *result = data; 115 const struct pci_error_handlers *err_handler; 116 117 device_lock(&dev->dev); 118 pdrv = dev->driver; 119 if (!pdrv || 120 !pdrv->err_handler || 121 !pdrv->err_handler->mmio_enabled) 122 goto out; 123 124 err_handler = pdrv->err_handler; 125 vote = err_handler->mmio_enabled(dev); 126 *result = merge_result(*result, vote); 127 out: 128 device_unlock(&dev->dev); 129 return 0; 130 } 131 132 static int report_slot_reset(struct pci_dev *dev, void *data) 133 { 134 struct pci_driver *pdrv; 135 pci_ers_result_t vote, *result = data; 136 const struct pci_error_handlers *err_handler; 137 138 device_lock(&dev->dev); 139 pdrv = dev->driver; 140 if (!pdrv || 141 !pdrv->err_handler || 142 !pdrv->err_handler->slot_reset) 143 goto out; 144 145 err_handler = pdrv->err_handler; 146 vote = err_handler->slot_reset(dev); 147 *result = merge_result(*result, vote); 148 out: 149 device_unlock(&dev->dev); 150 return 0; 151 } 152 153 static int report_resume(struct pci_dev *dev, void *data) 154 { 155 struct pci_driver *pdrv; 156 const struct pci_error_handlers *err_handler; 157 158 device_lock(&dev->dev); 159 pdrv = dev->driver; 160 if (!pci_dev_set_io_state(dev, pci_channel_io_normal) || 161 !pdrv || 162 !pdrv->err_handler || 163 !pdrv->err_handler->resume) 164 goto out; 165 166 err_handler = pdrv->err_handler; 167 err_handler->resume(dev); 168 out: 169 pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED); 170 device_unlock(&dev->dev); 171 return 0; 172 } 173 174 /** 175 * pci_walk_bridge - walk bridges potentially AER affected 176 * @bridge: bridge which may be a Port, an RCEC, or an RCiEP 177 * @cb: callback to be called for each device found 178 * @userdata: arbitrary pointer to be passed to callback 179 * 180 * If the device provided is a bridge, walk the subordinate bus, including 181 * any bridged devices on buses under this bus. Call the provided callback 182 * on each device found. 183 * 184 * If the device provided has no subordinate bus, e.g., an RCEC or RCiEP, 185 * call the callback on the device itself. 186 */ 187 static void pci_walk_bridge(struct pci_dev *bridge, 188 int (*cb)(struct pci_dev *, void *), 189 void *userdata) 190 { 191 if (bridge->subordinate) 192 pci_walk_bus(bridge->subordinate, cb, userdata); 193 else 194 cb(bridge, userdata); 195 } 196 197 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, 198 pci_channel_state_t state, 199 pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev)) 200 { 201 int type = pci_pcie_type(dev); 202 struct pci_dev *bridge; 203 pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER; 204 struct pci_host_bridge *host = pci_find_host_bridge(dev->bus); 205 206 /* 207 * If the error was detected by a Root Port, Downstream Port, RCEC, 208 * or RCiEP, recovery runs on the device itself. For Ports, that 209 * also includes any subordinate devices. 210 * 211 * If it was detected by another device (Endpoint, etc), recovery 212 * runs on the device and anything else under the same Port, i.e., 213 * everything under "bridge". 214 */ 215 if (type == PCI_EXP_TYPE_ROOT_PORT || 216 type == PCI_EXP_TYPE_DOWNSTREAM || 217 type == PCI_EXP_TYPE_RC_EC || 218 type == PCI_EXP_TYPE_RC_END) 219 bridge = dev; 220 else 221 bridge = pci_upstream_bridge(dev); 222 223 pci_walk_bridge(bridge, pci_pm_runtime_get_sync, NULL); 224 225 pci_dbg(bridge, "broadcast error_detected message\n"); 226 if (state == pci_channel_io_frozen) { 227 pci_walk_bridge(bridge, report_frozen_detected, &status); 228 if (reset_subordinates(bridge) != PCI_ERS_RESULT_RECOVERED) { 229 pci_warn(bridge, "subordinate device reset failed\n"); 230 goto failed; 231 } 232 } else { 233 pci_walk_bridge(bridge, report_normal_detected, &status); 234 } 235 236 if (status == PCI_ERS_RESULT_CAN_RECOVER) { 237 status = PCI_ERS_RESULT_RECOVERED; 238 pci_dbg(bridge, "broadcast mmio_enabled message\n"); 239 pci_walk_bridge(bridge, report_mmio_enabled, &status); 240 } 241 242 if (status == PCI_ERS_RESULT_NEED_RESET) { 243 /* 244 * TODO: Should call platform-specific 245 * functions to reset slot before calling 246 * drivers' slot_reset callbacks? 247 */ 248 status = PCI_ERS_RESULT_RECOVERED; 249 pci_dbg(bridge, "broadcast slot_reset message\n"); 250 pci_walk_bridge(bridge, report_slot_reset, &status); 251 } 252 253 if (status != PCI_ERS_RESULT_RECOVERED) 254 goto failed; 255 256 pci_dbg(bridge, "broadcast resume message\n"); 257 pci_walk_bridge(bridge, report_resume, &status); 258 259 /* 260 * If we have native control of AER, clear error status in the device 261 * that detected the error. If the platform retained control of AER, 262 * it is responsible for clearing this status. In that case, the 263 * signaling device may not even be visible to the OS. 264 */ 265 if (host->native_aer || pcie_ports_native) { 266 pcie_clear_device_status(dev); 267 pci_aer_clear_nonfatal_status(dev); 268 } 269 270 pci_walk_bridge(bridge, pci_pm_runtime_put, NULL); 271 272 pci_info(bridge, "device recovery successful\n"); 273 return status; 274 275 failed: 276 pci_walk_bridge(bridge, pci_pm_runtime_put, NULL); 277 278 pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT); 279 280 /* TODO: Should kernel panic here? */ 281 pci_info(bridge, "device recovery failed\n"); 282 283 return status; 284 } 285