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

source code of linux/drivers/pci/pcie/edr.c