diff options
Diffstat (limited to 'drivers/pci/pcie/edr.c')
| -rw-r--r-- | drivers/pci/pcie/edr.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c new file mode 100644 index 000000000..87734e4c3 --- /dev/null +++ b/drivers/pci/pcie/edr.c @@ -0,0 +1,240 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI Error Disconnect Recover support + * Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> + * + * Copyright (C) 2020 Intel Corp. + */ + +#define dev_fmt(fmt) "EDR: " fmt + +#include <linux/pci.h> +#include <linux/pci-acpi.h> + +#include "portdrv.h" +#include "../pci.h" + +#define EDR_PORT_DPC_ENABLE_DSM 0x0C +#define EDR_PORT_LOCATE_DSM 0x0D +#define EDR_OST_SUCCESS 0x80 +#define EDR_OST_FAILED 0x81 + +/* + * _DSM wrapper function to enable/disable DPC + * @pdev : PCI device structure + * + * returns 0 on success or errno on failure. + */ +static int acpi_enable_dpc(struct pci_dev *pdev) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + union acpi_object *obj, argv4, req; + int status = 0; + + /* + * Behavior when calling unsupported _DSM functions is undefined, + * so check whether EDR_PORT_DPC_ENABLE_DSM is supported. + */ + if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + 1ULL << EDR_PORT_DPC_ENABLE_DSM)) + return 0; + + req.type = ACPI_TYPE_INTEGER; + req.integer.value = 1; + + argv4.type = ACPI_TYPE_PACKAGE; + argv4.package.count = 1; + argv4.package.elements = &req; + + /* + * Per Downstream Port Containment Related Enhancements ECN to PCI + * Firmware Specification r3.2, sec 4.6.12, EDR_PORT_DPC_ENABLE_DSM is + * optional. Return success if it's not implemented. + */ + obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + EDR_PORT_DPC_ENABLE_DSM, &argv4); + if (!obj) + return 0; + + if (obj->type != ACPI_TYPE_INTEGER) { + pci_err(pdev, FW_BUG "Enable DPC _DSM returned non integer\n"); + status = -EIO; + } + + if (obj->integer.value != 1) { + pci_err(pdev, "Enable DPC _DSM failed to enable DPC\n"); + status = -EIO; + } + + ACPI_FREE(obj); + + return status; +} + +/* + * _DSM wrapper function to locate DPC port + * @pdev : Device which received EDR event + * + * Returns pci_dev or NULL. Caller is responsible for dropping a reference + * on the returned pci_dev with pci_dev_put(). + */ +static struct pci_dev *acpi_dpc_port_get(struct pci_dev *pdev) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + union acpi_object *obj; + u16 port; + + /* + * Behavior when calling unsupported _DSM functions is undefined, + * so check whether EDR_PORT_DPC_ENABLE_DSM is supported. + */ + if (!acpi_check_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + 1ULL << EDR_PORT_LOCATE_DSM)) + return pci_dev_get(pdev); + + obj = acpi_evaluate_dsm(adev->handle, &pci_acpi_dsm_guid, 5, + EDR_PORT_LOCATE_DSM, NULL); + if (!obj) + return pci_dev_get(pdev); + + if (obj->type != ACPI_TYPE_INTEGER) { + ACPI_FREE(obj); + pci_err(pdev, FW_BUG "Locate Port _DSM returned non integer\n"); + return NULL; + } + + /* + * Firmware returns DPC port BDF details in following format: + * 15:8 = bus + * 7:3 = device + * 2:0 = function + */ + port = obj->integer.value; + + ACPI_FREE(obj); + + return pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus), + PCI_BUS_NUM(port), port & 0xff); +} + +/* + * _OST wrapper function to let firmware know the status of EDR event + * @pdev : Device used to send _OST + * @edev : Device which experienced EDR event + * @status : Status of EDR event + */ +static int acpi_send_edr_status(struct pci_dev *pdev, struct pci_dev *edev, + u16 status) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + u32 ost_status; + + pci_dbg(pdev, "Status for %s: %#x\n", pci_name(edev), status); + + ost_status = PCI_DEVID(edev->bus->number, edev->devfn) << 16; + ost_status |= status; + + status = acpi_evaluate_ost(adev->handle, ACPI_NOTIFY_DISCONNECT_RECOVER, + ost_status, NULL); + if (ACPI_FAILURE(status)) + return -EINVAL; + + return 0; +} + +static void edr_handle_event(acpi_handle handle, u32 event, void *data) +{ + struct pci_dev *pdev = data, *edev; + pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT; + u16 status; + + if (event != ACPI_NOTIFY_DISCONNECT_RECOVER) + return; + + pci_info(pdev, "EDR event received\n"); + + /* Locate the port which issued EDR event */ + edev = acpi_dpc_port_get(pdev); + if (!edev) { + pci_err(pdev, "Firmware failed to locate DPC port\n"); + return; + } + + pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev)); + + /* If port does not support DPC, just send the OST */ + if (!edev->dpc_cap) { + pci_err(edev, FW_BUG "This device doesn't support DPC\n"); + goto send_ost; + } + + /* Check if there is a valid DPC trigger */ + pci_read_config_word(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &status); + if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) { + pci_err(edev, "Invalid DPC trigger %#010x\n", status); + goto send_ost; + } + + dpc_process_error(edev); + pci_aer_raw_clear_status(edev); + + /* + * Irrespective of whether the DPC event is triggered by ERR_FATAL + * or ERR_NONFATAL, since the link is already down, use the FATAL + * error recovery path for both cases. + */ + estate = pcie_do_recovery(edev, pci_channel_io_frozen, dpc_reset_link); + +send_ost: + + /* + * If recovery is successful, send _OST(0xF, BDF << 16 | 0x80) + * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81). + */ + if (estate == PCI_ERS_RESULT_RECOVERED) { + pci_dbg(edev, "DPC port successfully recovered\n"); + pcie_clear_device_status(edev); + acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS); + } else { + pci_dbg(edev, "DPC port recovery failed\n"); + acpi_send_edr_status(pdev, edev, EDR_OST_FAILED); + } + + pci_dev_put(edev); +} + +void pci_acpi_add_edr_notifier(struct pci_dev *pdev) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + acpi_status status; + + if (!adev) { + pci_dbg(pdev, "No valid ACPI node, skipping EDR init\n"); + return; + } + + status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY, + edr_handle_event, pdev); + if (ACPI_FAILURE(status)) { + pci_err(pdev, "Failed to install notify handler\n"); + return; + } + + if (acpi_enable_dpc(pdev)) + acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY, + edr_handle_event); + else + pci_dbg(pdev, "Notify handler installed\n"); +} + +void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + + if (!adev) + return; + + acpi_remove_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY, + edr_handle_event); + pci_dbg(pdev, "Notify handler removed\n"); +} |