1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCI Error Disconnect Recover support
4 * Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
5 *
6 * Copyright (C) 2020 Intel Corp.
7 */
8
9 #define dev_fmt(fmt) "EDR: " fmt
10
11 #include <linux/pci.h>
12 #include <linux/pci-acpi.h>
13
14 #include "portdrv.h"
15 #include "../pci.h"
16
17 #define EDR_PORT_DPC_ENABLE_DSM 0x0C
18 #define EDR_PORT_LOCATE_DSM 0x0D
19 #define EDR_OST_SUCCESS 0x80
20 #define EDR_OST_FAILED 0x81
21
22 /*
23 * _DSM wrapper function to enable/disable DPC
24 * @pdev : PCI device structure
25 *
26 * returns 0 on success or errno on failure.
27 */
acpi_enable_dpc(struct pci_dev * pdev)28 static int acpi_enable_dpc(struct pci_dev *pdev)
29 {
30 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
31 union acpi_object *obj, argv4, req;
32 int status = 0;
33
34 /*
35 * Per PCI Firmware r3.3, sec 4.6.12, EDR_PORT_DPC_ENABLE_DSM is
36 * optional. Return success if it's not implemented.
37 */
38 if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 6,
39 1ULL << EDR_PORT_DPC_ENABLE_DSM))
40 return 0;
41
42 req.type = ACPI_TYPE_INTEGER;
43 req.integer.value = 1;
44
45 argv4.type = ACPI_TYPE_PACKAGE;
46 argv4.package.count = 1;
47 argv4.package.elements = &req;
48
49 obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 6,
50 EDR_PORT_DPC_ENABLE_DSM, &argv4);
51 if (!obj)
52 return 0;
53
54 if (obj->type != ACPI_TYPE_INTEGER) {
55 pci_err(pdev, FW_BUG "Enable DPC _DSM returned non integer\n");
56 status = -EIO;
57 }
58
59 if (obj->integer.value != 1) {
60 pci_err(pdev, "Enable DPC _DSM failed to enable DPC\n");
61 status = -EIO;
62 }
63
64 ACPI_FREE(obj);
65
66 return status;
67 }
68
69 /*
70 * _DSM wrapper function to locate DPC port
71 * @pdev : Device which received EDR event
72 *
73 * Returns pci_dev or NULL. Caller is responsible for dropping a reference
74 * on the returned pci_dev with pci_dev_put().
75 */
acpi_dpc_port_get(struct pci_dev * pdev)76 static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev)
77 {
78 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
79 union acpi_object *obj;
80 u16 port;
81
82 /*
83 * If EDR_PORT_LOCATE_DSM is not implemented under the target of
84 * EDR, the target is the port that experienced the containment
85 * event (PCI Firmware r3.3, sec 4.6.13).
86 */
87 if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
88 1ULL << EDR_PORT_LOCATE_DSM))
89 return pci_dev_get(pdev);
90
91 obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5,
92 EDR_PORT_LOCATE_DSM, NULL);
93 if (!obj)
94 return pci_dev_get(pdev);
95
96 if (obj->type != ACPI_TYPE_INTEGER) {
97 ACPI_FREE(obj);
98 pci_err(pdev, FW_BUG "Locate Port _DSM returned non integer\n");
99 return NULL;
100 }
101
102 /*
103 * Bit 31 represents the success/failure of the operation. If bit
104 * 31 is set, the operation failed.
105 */
106 if (obj->integer.value & BIT(31)) {
107 ACPI_FREE(obj);
108 pci_err(pdev, "Locate Port _DSM failed\n");
109 return NULL;
110 }
111
112 /*
113 * Firmware returns DPC port BDF details in following format:
114 * 15:8 = bus
115 * 7:3 = device
116 * 2:0 = function
117 */
118 port = obj->integer.value;
119
120 ACPI_FREE(obj);
121
122 return pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
123 PCI_BUS_NUM(port), port & 0xff);
124 }
125
126 /*
127 * _OST wrapper function to let firmware know the status of EDR event
128 * @pdev : Device used to send _OST
129 * @edev : Device which experienced EDR event
130 * @status : Status of EDR event
131 */
acpi_send_edr_status(struct pci_dev * pdev,struct pci_dev * edev,u16 status)132 static int acpi_send_edr_status(struct pci_dev *pdev, struct pci_dev *edev,
133 u16 status)
134 {
135 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
136 u32 ost_status;
137
138 pci_dbg(pdev, "Status for %s: %#x\n", pci_name(edev), status);
139
140 ost_status = PCI_DEVID(edev->bus->number, edev->devfn) << 16;
141 ost_status |= status;
142
143 status = acpi_evaluate_ost(adev->handle, ACPI_NOTIFY_DISCONNECT_RECOVER,
144 ost_status, NULL);
145 if (ACPI_FAILURE(status))
146 return -EINVAL;
147
148 return 0;
149 }
150
edr_handle_event(acpi_handle handle,u32 event,void * data)151 static void edr_handle_event(acpi_handle handle, u32 event, void *data)
152 {
153 struct pci_dev *pdev = data, *edev;
154 pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
155 u16 status;
156
157 if (event != ACPI_NOTIFY_DISCONNECT_RECOVER)
158 return;
159
160 /*
161 * pdev is a Root Port or Downstream Port that is still present and
162 * has triggered a containment event, e.g., DPC, so its child
163 * devices have been disconnected (ACPI r6.5, sec 5.6.6).
164 */
165 pci_info(pdev, "EDR event received\n");
166
167 /*
168 * Locate the port that experienced the containment event. pdev
169 * may be that port or a parent of it (PCI Firmware r3.3, sec
170 * 4.6.13).
171 */
172 edev = acpi_dpc_port_get(pdev);
173 if (!edev) {
174 pci_err(pdev, "Firmware failed to locate DPC port\n");
175 return;
176 }
177
178 pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev));
179
180 /* If port does not support DPC, just send the OST */
181 if (!edev->dpc_cap) {
182 pci_err(edev, FW_BUG "This device doesn't support DPC\n");
183 goto send_ost;
184 }
185
186 /* Check if there is a valid DPC trigger */
187 pci_read_config_word(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
188 if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
189 pci_err(edev, "Invalid DPC trigger %#010x\n", status);
190 goto send_ost;
191 }
192
193 dpc_process_error(edev);
194 pci_aer_raw_clear_status(edev);
195
196 /*
197 * Irrespective of whether the DPC event is triggered by ERR_FATAL
198 * or ERR_NONFATAL, since the link is already down, use the FATAL
199 * error recovery path for both cases.
200 */
201 estate = pcie_do_recovery(edev, pci_channel_io_frozen, dpc_reset_link);
202
203 send_ost:
204
205 /*
206 * If recovery is successful, send _OST(0xF, BDF << 16 | 0x80)
207 * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81).
208 */
209 if (estate == PCI_ERS_RESULT_RECOVERED) {
210 pci_dbg(edev, "DPC port successfully recovered\n");
211 pcie_clear_device_status(edev);
212 acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS);
213 } else {
214 pci_dbg(edev, "DPC port recovery failed\n");
215 acpi_send_edr_status(pdev, edev, EDR_OST_FAILED);
216 }
217
218 pci_dev_put(edev);
219 }
220
pci_acpi_add_edr_notifier(struct pci_dev * pdev)221 void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
222 {
223 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
224 acpi_status status;
225
226 if (!adev) {
227 pci_dbg(pdev, "No valid ACPI node, skipping EDR init\n");
228 return;
229 }
230
231 status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
232 edr_handle_event, pdev);
233 if (ACPI_FAILURE(status)) {
234 pci_err(pdev, "Failed to install notify handler\n");
235 return;
236 }
237
238 if (acpi_enable_dpc(pdev))
239 acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
240 edr_handle_event);
241 else
242 pci_dbg(pdev, "Notify handler installed\n");
243 }
244
pci_acpi_remove_edr_notifier(struct pci_dev * pdev)245 void pci_acpi_remove_edr_notifier(struct pci_dev *pdev)
246 {
247 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
248
249 if (!adev)
250 return;
251
252 acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
253 edr_handle_event);
254 pci_dbg(pdev, "Notify handler removed\n");
255 }
256