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	 * 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 */
 76static 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 */
132static 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
151static 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
203send_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
221void 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
245void 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}