1 // SPDX-License-Identifier: GPL-2.0
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.
8 * Copyright (C) 2006 Intel Corp.
9 * Tom Long Nguyen (tom.l.nguyen@intel.com)
10 * Zhang Yanmin (yanmin.zhang@intel.com)
13 #define dev_fmt(fmt) "AER: " fmt
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>
23 static pci_ers_result_t merge_result(enum pci_ers_result orig,
24 enum pci_ers_result new)
26 if (new == PCI_ERS_RESULT_NO_AER_DRIVER)
27 return PCI_ERS_RESULT_NO_AER_DRIVER;
29 if (new == PCI_ERS_RESULT_NONE)
33 case PCI_ERS_RESULT_CAN_RECOVER:
34 case PCI_ERS_RESULT_RECOVERED:
37 case PCI_ERS_RESULT_DISCONNECT:
38 if (new == PCI_ERS_RESULT_NEED_RESET)
39 orig = PCI_ERS_RESULT_NEED_RESET;
48 static int report_error_detected(struct pci_dev *dev,
49 pci_channel_state_t state,
50 enum pci_ers_result *result)
52 struct pci_driver *pdrv;
53 pci_ers_result_t vote;
54 const struct pci_error_handlers *err_handler;
56 device_lock(&dev->dev);
58 if (pci_dev_is_disconnected(dev)) {
59 vote = PCI_ERS_RESULT_DISCONNECT;
60 } else if (!pci_dev_set_io_state(dev, state)) {
61 pci_info(dev, "can't recover (state transition %u -> %u invalid)\n",
62 dev->error_state, state);
63 vote = PCI_ERS_RESULT_NONE;
64 } else if (!pdrv || !pdrv->err_handler ||
65 !pdrv->err_handler->error_detected) {
67 * If any device in the subtree does not have an error_detected
68 * callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent
69 * error callbacks of "any" device in the subtree, and will
70 * exit in the disconnected error state.
72 if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
73 vote = PCI_ERS_RESULT_NO_AER_DRIVER;
74 pci_info(dev, "can't recover (no error_detected callback)\n");
76 vote = PCI_ERS_RESULT_NONE;
79 err_handler = pdrv->err_handler;
80 vote = err_handler->error_detected(dev, state);
82 pci_uevent_ers(dev, vote);
83 *result = merge_result(*result, vote);
84 device_unlock(&dev->dev);
88 static int report_frozen_detected(struct pci_dev *dev, void *data)
90 return report_error_detected(dev, pci_channel_io_frozen, data);
93 static int report_normal_detected(struct pci_dev *dev, void *data)
95 return report_error_detected(dev, pci_channel_io_normal, data);
98 static int report_mmio_enabled(struct pci_dev *dev, void *data)
100 struct pci_driver *pdrv;
101 pci_ers_result_t vote, *result = data;
102 const struct pci_error_handlers *err_handler;
104 device_lock(&dev->dev);
107 !pdrv->err_handler ||
108 !pdrv->err_handler->mmio_enabled)
111 err_handler = pdrv->err_handler;
112 vote = err_handler->mmio_enabled(dev);
113 *result = merge_result(*result, vote);
115 device_unlock(&dev->dev);
119 static int report_slot_reset(struct pci_dev *dev, void *data)
121 struct pci_driver *pdrv;
122 pci_ers_result_t vote, *result = data;
123 const struct pci_error_handlers *err_handler;
125 device_lock(&dev->dev);
128 !pdrv->err_handler ||
129 !pdrv->err_handler->slot_reset)
132 err_handler = pdrv->err_handler;
133 vote = err_handler->slot_reset(dev);
134 *result = merge_result(*result, vote);
136 device_unlock(&dev->dev);
140 static int report_resume(struct pci_dev *dev, void *data)
142 struct pci_driver *pdrv;
143 const struct pci_error_handlers *err_handler;
145 device_lock(&dev->dev);
147 if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
149 !pdrv->err_handler ||
150 !pdrv->err_handler->resume)
153 err_handler = pdrv->err_handler;
154 err_handler->resume(dev);
156 pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
157 device_unlock(&dev->dev);
162 * pci_walk_bridge - walk bridges potentially AER affected
163 * @bridge: bridge which may be a Port, an RCEC, or an RCiEP
164 * @cb: callback to be called for each device found
165 * @userdata: arbitrary pointer to be passed to callback
167 * If the device provided is a bridge, walk the subordinate bus, including
168 * any bridged devices on buses under this bus. Call the provided callback
169 * on each device found.
171 * If the device provided has no subordinate bus, e.g., an RCEC or RCiEP,
172 * call the callback on the device itself.
174 static void pci_walk_bridge(struct pci_dev *bridge,
175 int (*cb)(struct pci_dev *, void *),
178 if (bridge->subordinate)
179 pci_walk_bus(bridge->subordinate, cb, userdata);
181 cb(bridge, userdata);
184 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
185 pci_channel_state_t state,
186 pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev))
188 int type = pci_pcie_type(dev);
189 struct pci_dev *bridge;
190 pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
191 struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
194 * If the error was detected by a Root Port, Downstream Port, RCEC,
195 * or RCiEP, recovery runs on the device itself. For Ports, that
196 * also includes any subordinate devices.
198 * If it was detected by another device (Endpoint, etc), recovery
199 * runs on the device and anything else under the same Port, i.e.,
200 * everything under "bridge".
202 if (type == PCI_EXP_TYPE_ROOT_PORT ||
203 type == PCI_EXP_TYPE_DOWNSTREAM ||
204 type == PCI_EXP_TYPE_RC_EC ||
205 type == PCI_EXP_TYPE_RC_END)
208 bridge = pci_upstream_bridge(dev);
210 pci_dbg(bridge, "broadcast error_detected message\n");
211 if (state == pci_channel_io_frozen) {
212 pci_walk_bridge(bridge, report_frozen_detected, &status);
213 if (reset_subordinates(bridge) != PCI_ERS_RESULT_RECOVERED) {
214 pci_warn(bridge, "subordinate device reset failed\n");
218 pci_walk_bridge(bridge, report_normal_detected, &status);
221 if (status == PCI_ERS_RESULT_CAN_RECOVER) {
222 status = PCI_ERS_RESULT_RECOVERED;
223 pci_dbg(bridge, "broadcast mmio_enabled message\n");
224 pci_walk_bridge(bridge, report_mmio_enabled, &status);
227 if (status == PCI_ERS_RESULT_NEED_RESET) {
229 * TODO: Should call platform-specific
230 * functions to reset slot before calling
231 * drivers' slot_reset callbacks?
233 status = PCI_ERS_RESULT_RECOVERED;
234 pci_dbg(bridge, "broadcast slot_reset message\n");
235 pci_walk_bridge(bridge, report_slot_reset, &status);
238 if (status != PCI_ERS_RESULT_RECOVERED)
241 pci_dbg(bridge, "broadcast resume message\n");
242 pci_walk_bridge(bridge, report_resume, &status);
245 * If we have native control of AER, clear error status in the device
246 * that detected the error. If the platform retained control of AER,
247 * it is responsible for clearing this status. In that case, the
248 * signaling device may not even be visible to the OS.
250 if (host->native_aer || pcie_ports_native) {
251 pcie_clear_device_status(dev);
252 pci_aer_clear_nonfatal_status(dev);
254 pci_info(bridge, "device recovery successful\n");
258 pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT);
260 /* TODO: Should kernel panic here? */
261 pci_info(bridge, "device recovery failed\n");