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(adev->handle, &pci_acpi_dsm_guid, 5, 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 /* 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(adev->handle, &pci_acpi_dsm_guid, 5, 55 EDR_PORT_DPC_ENABLE_DSM, &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(adev->handle, &pci_acpi_dsm_guid, 5, 92 1ULL << EDR_PORT_LOCATE_DSM)) 93 return pci_dev_get(pdev); 94 95 obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5, 96 EDR_PORT_LOCATE_DSM, NULL); 97 if (!obj) 98 return pci_dev_get(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(pci_domain_nr(pdev->bus), 117 PCI_BUS_NUM(port), 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(adev->handle, ACPI_NOTIFY_DISCONNECT_RECOVER, 138 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(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &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(edev); 188 pci_aer_raw_clear_status(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(edev, pci_channel_io_frozen, 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(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(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(adev->handle, ACPI_SYSTEM_NOTIFY, 226 edr_handle_event, 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(adev->handle, ACPI_SYSTEM_NOTIFY, 234 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(adev->handle, ACPI_SYSTEM_NOTIFY, 247 edr_handle_event); 248 pci_dbg(pdev, "Notify handler removed\n"); 249} 250