From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> As per PCI firmware specification v3.2 ECN (https://members.pcisig.com/wg/PCI-SIG/document/12614), when firmware owns Downstream Port Containment (DPC), its expected to use the "Error Disconnect Recover" (EDR) notification to alert OSPM of a DPC event and if OS supports EDR, its expected to handle the software state invalidation and port recovery in OS and let firmware know the recovery status via _OST ACPI call. Since EDR is a hybrid service, DPC service shall be enabled in OS even if AER is not natively enabled in OS. Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> --- drivers/pci/pcie/Kconfig | 10 ++ drivers/pci/pcie/dpc.c | 206 ++++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv_core.c | 9 +- 3 files changed, 223 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 362eb8cfa53b..9a05015af7cd 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -150,3 +150,13 @@ config PCIE_BW This enables PCI Express Bandwidth Change Notification. If you know link width or rate changes occur only to correct unreliable links, you may answer Y. + +config PCIE_EDR + bool "PCI Express Error Disconnect Recover support" + default n + depends on PCIE_DPC && ACPI + help + This options adds Error Disconnect Recover support as specified + in PCI firmware specification v3.2 Downstream Port Containment + Related Enhancements ECN. Enable this if you want to support hybrid + DPC model which uses both firmware and OS to implement DPC. diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index 95810b4b0adc..131fadd29ae2 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -11,6 +11,7 @@ #include <linux/interrupt.h> #include <linux/init.h> #include <linux/pci.h> +#include <linux/acpi.h> #include "portdrv.h" #include "../pci.h" @@ -22,8 +23,22 @@ struct dpc_dev { u8 rp_log_size; /* Set True if DPC is handled in firmware */ bool firmware_dpc; + pci_ers_result_t error_state; +#ifdef CONFIG_ACPI + struct acpi_device *adev; +#endif }; +#ifdef CONFIG_ACPI + +#define EDR_PORT_ENABLE_DSM 0x0C +#define EDR_PORT_LOCATE_DSM 0x0D + +static const guid_t pci_acpi_dsm_guid = + GUID_INIT(0xe5c937d0, 0x3553, 0x4d7a, + 0x91, 0x17, 0xea, 0x4d, 0x19, 0xc3, 0x43, 0x4d); +#endif + static const char * const rp_pio_error_string[] = { "Configuration Request received UR Completion", /* Bit Position 0 */ "Configuration Request received CA Completion", /* Bit Position 1 */ @@ -297,6 +312,167 @@ static irqreturn_t dpc_irq(int irq, void *context) return IRQ_HANDLED; } +static void dpc_error_resume(struct pci_dev *dev) +{ + struct dpc_dev *dpc = to_dpc_dev(dev); + + dpc->error_state = PCI_ERS_RESULT_RECOVERED; +} + +#ifdef CONFIG_ACPI + +/* + * _DSM wrapper function to enable/disable DPC port. + * @dpc : DPC device structure + * @enable: status of DPC port (0 or 1). + * + * returns 0 on success or errno on failure. + */ +static int acpi_enable_dpc_port(struct dpc_dev *dpc, bool enable) +{ + union acpi_object *obj; + int status; + union acpi_object argv4; + struct pci_dev *pdev = dpc->dev->port; + + dev_dbg(&pdev->dev, "Enable DPC port, value:%d\n", enable); + + argv4.type = ACPI_TYPE_INTEGER; + argv4.integer.value = enable; + + obj = acpi_evaluate_dsm(dpc->adev->handle, &pci_acpi_dsm_guid, 1, + EDR_PORT_ENABLE_DSM, &argv4); + if (!obj) + return -EIO; + + if (obj->type == ACPI_TYPE_INTEGER && obj->integer.value == enable) + status = 0; + else + status = -EIO; + + ACPI_FREE(obj); + + return status; +} + +/* + * _DSM wrapper function to locate DPC port. + * @dpc : DPC device structure + * + * returns pci_dev. + */ +static struct pci_dev *acpi_locate_dpc_port(struct dpc_dev *dpc) +{ + union acpi_object *obj; + u16 port; + struct pci_dev *pdev = dpc->dev->port; + + dev_dbg(&pdev->dev, "Locate DPC port\n"); + + obj = acpi_evaluate_dsm(dpc->adev->handle, &pci_acpi_dsm_guid, 1, + EDR_PORT_LOCATE_DSM, NULL); + if (!obj) + return dpc->dev->port; + + if (obj->type == ACPI_TYPE_INTEGER) { + /* + * 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); + } else { + ACPI_FREE(obj); + return dpc->dev->port; + } + + return pci_get_domain_bus_and_slot(0, PCI_BUS_NUM(port), port & 0xff); +} + +/* + * _OST wrapper function to let firmware know the status of EDR event. + * @dpc : DPC device structure. + * @status: Status of EDR event. + */ +static int acpi_send_edr_status(struct dpc_dev *dpc, u16 status) +{ + u32 ost_status; + struct pci_dev *pdev = dpc->dev->port; + + dev_dbg(&pdev->dev, "Sending EDR status :%x\n", status); + + ost_status = PCI_DEVID(pdev->bus->number, pdev->devfn); + ost_status = (ost_status << 16) | status; + + status = acpi_evaluate_ost(dpc->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 dpc_dev *dpc = (struct dpc_dev *) data; + struct pci_dev *pdev = dpc->dev->port; + u16 status, cap; + + dev_info(&pdev->dev, "ACPI event %x received\n", event); + + if (event != ACPI_NOTIFY_DISCONNECT_RECOVER) + return; + + dev_info(&pdev->dev, "Valid EDR event received\n"); + + /* + * Check if _DSM(0xD) is available, and if present locate the + * port which issued EDR event. + */ + pdev = acpi_locate_dpc_port(dpc); + if (!pdev) { + pdev = dpc->dev->port; + dev_err(&pdev->dev, "No valid port found\n"); + return; + } + + dpc = to_dpc_dev(pdev); + dpc->error_state = PCI_ERS_RESULT_DISCONNECT; + cap = dpc->cap_pos; + + /* + * Check if the port supports DPC: + * + * If port supports DPC, then fall back to default error + * recovery. + */ + if (cap) { + /* Check if there is a valid DPC trigger */ + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status); + if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) { + dev_err(&pdev->dev, "Invalid DPC trigger %x\n", status); + return; + } + dpc_process_error(dpc); + } + + /* + * If recovery is successful, send _OST(0xF, BDF << 16 | 0x80) + * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81). + */ + if (dpc->error_state == PCI_ERS_RESULT_RECOVERED) + status = 0x80; + else + status = 0x81; + + acpi_send_edr_status(dpc, status); +} + +#endif + #define FLAG(x, y) (((x) & (y)) ? '+' : '-') static int dpc_probe(struct pcie_device *dev) { @@ -305,6 +481,10 @@ static int dpc_probe(struct pcie_device *dev) struct device *device = &dev->device; int status; u16 ctl, cap; +#ifdef CONFIG_ACPI + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + acpi_status astatus; +#endif dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL); if (!dpc) @@ -313,6 +493,7 @@ static int dpc_probe(struct pcie_device *dev) dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC); dpc->dev = dev; set_service_data(dev, dpc); + dpc->error_state = PCI_ERS_RESULT_NONE; if (pcie_aer_get_firmware_first(pdev)) dpc->firmware_dpc = 1; @@ -335,6 +516,30 @@ static int dpc_probe(struct pcie_device *dev) } } +#ifdef CONFIG_ACPI + if (dpc->firmware_dpc) { + if (!adev) { + dev_err(device, "No valid ACPI device found\n"); + return -ENODEV; + } + + dpc->adev = adev; + + /* Register notifier for ACPI_SYSTEM_NOTIFY events */ + astatus = acpi_install_notify_handler(adev->handle, + ACPI_SYSTEM_NOTIFY, + edr_handle_event, + dpc); + + if (ACPI_FAILURE(astatus)) { + dev_err(device, + "Install ACPI_SYSTEM_NOTIFY handler failed\n"); + return -EBUSY; + } + + acpi_enable_dpc_port(dpc, true); + } +#endif pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap); pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl); @@ -385,6 +590,7 @@ static struct pcie_port_service_driver dpcdriver = { .probe = dpc_probe, .remove = dpc_remove, .reset_link = dpc_reset_link, + .error_resume = dpc_error_resume, }; int __init pcie_dpc_init(void) diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 0a59ac574be1..1b54a39df795 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -250,9 +250,14 @@ static int get_port_device_capability(struct pci_dev *dev) pcie_pme_interrupt_enable(dev, false); } + /* + * If EDR support is enabled in OS, then even if AER is not handled in + * OS, DPC service can be enabled. + */ if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) && - pci_aer_available() && services & PCIE_PORT_SERVICE_AER && - (pcie_ports_native || host->native_dpc)) + ((IS_ENABLED(CONFIG_PCIE_EDR) && !host->native_dpc) || + (pci_aer_available() && services & PCIE_PORT_SERVICE_AER && + (pcie_ports_native || host->native_dpc)))) services |= PCIE_PORT_SERVICE_DPC; if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || -- 2.20.1
