drivers/pci/pcie/edr.c

   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  */
  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          * 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  */
  81 static 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  */
 126 static 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
 145 static 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         pci_info(pdev, "EDR event received\n");
 155
 156         /* Locate the port which issued EDR event */
 157         edev = acpi_dpc_port_get(pdev);
 158         if (!edev) {
 159                 pci_err(pdev, "Firmware failed to locate DPC port\n");
 160                 return;
 161         }
 162
 163         pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev));
 164
 165         /* If port does not support DPC, just send the OST */
 166         if (!edev->dpc_cap) {
 167                 pci_err(edev, FW_BUG "This device doesn't support DPC\n");
 168                 goto send_ost;
 169         }
 170
 171         /* Check if there is a valid DPC trigger */
 172         pci_read_config_word(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
 173         if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
 174                 pci_err(edev, "Invalid DPC trigger %#010x\n", status);
 175                 goto send_ost;
 176         }
 177
 178         dpc_process_error(edev);
 179         pci_aer_raw_clear_status(edev);
 180
 181         /*
 182          * Irrespective of whether the DPC event is triggered by ERR_FATAL
 183          * or ERR_NONFATAL, since the link is already down, use the FATAL
 184          * error recovery path for both cases.
 185          */
 186         estate = pcie_do_recovery(edev, pci_channel_io_frozen, dpc_reset_link);
 187
 188 send_ost:
 189
 190         /*
 191          * If recovery is successful, send _OST(0xF, BDF << 16 | 0x80)
 192          * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81).
 193          */
 194         if (estate == PCI_ERS_RESULT_RECOVERED) {
 195                 pci_dbg(edev, "DPC port successfully recovered\n");
 196                 acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS);
 197         } else {
 198                 pci_dbg(edev, "DPC port recovery failed\n");
 199                 acpi_send_edr_status(pdev, edev, EDR_OST_FAILED);
 200         }
 201
 202         pci_dev_put(edev);
 203 }
 204
 205 void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
 206 {
 207         struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 208         acpi_status status;
 209
 210         if (!adev) {
 211                 pci_dbg(pdev, "No valid ACPI node, skipping EDR init\n");
 212                 return;
 213         }
 214
 215         status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
 216                                              edr_handle_event, pdev);
 217         if (ACPI_FAILURE(status)) {
 218                 pci_err(pdev, "Failed to install notify handler\n");
 219                 return;
 220         }
 221
 222         if (acpi_enable_dpc(pdev))
 223                 acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
 224                                            edr_handle_event);
 225         else
 226                 pci_dbg(pdev, "Notify handler installed\n");
 227 }
 228
 229 void pci_acpi_remove_edr_notifier(struct pci_dev *pdev)
 230 {
 231         struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 232
 233         if (!adev)
 234                 return;
 235
 236         acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
 237                                    edr_handle_event);
 238         pci_dbg(pdev, "Notify handler removed\n");
 239 }