diff options
| -rw-r--r-- | drivers/pci/pci-acpi.c | 74 | ||||
| -rw-r--r-- | include/linux/pci-acpi.h | 2 | ||||
| -rw-r--r-- | include/linux/pci.h | 1 |
3 files changed, 77 insertions, 0 deletions
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index bea6be4992c3..5eba74716900 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -537,11 +537,32 @@ static struct pci_platform_pm_ops acpi_pci_platform_pm = { void acpi_pci_add_bus(struct pci_bus *bus) { + union acpi_object *obj; + struct pci_host_bridge *bridge; + if (acpi_pci_disabled || !bus->bridge) return; acpi_pci_slot_enumerate(bus); acpiphp_enumerate_slots(bus); + + /* + * For a host bridge, check its _DSM for function 8 and if + * that is available, mark it in pci_host_bridge. + */ + if (!pci_is_root_bus(bus)) + return; + + obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), pci_acpi_dsm_uuid, 3, + RESET_DELAY_DSM, NULL); + if (!obj) + return; + + if (obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 1) { + bridge = pci_find_host_bridge(bus); + bridge->ignore_reset_delay = 1; + } + ACPI_FREE(obj); } void acpi_pci_remove_bus(struct pci_bus *bus) @@ -567,6 +588,57 @@ static struct acpi_device *acpi_pci_find_companion(struct device *dev) check_children); } +/** + * pci_acpi_optimize_delay - optimize PCI D3 and D3cold delay from ACPI + * @pdev: the PCI device whose delay is to be updated + * @adev: the companion ACPI device of this PCI device + * + * Update the d3_delay and d3cold_delay of a PCI device from the ACPI _DSM + * control method of either the device itself or the PCI host bridge. + * + * Function 8, "Reset Delay," applies to the entire hierarchy below a PCI + * host bridge. If it returns one, the OS may assume that all devices in + * the hierarchy have already completed power-on reset delays. + * + * Function 9, "Device Readiness Durations," applies only to the object + * where it is located. It returns delay durations required after various + * events if the device requires less time than the spec requires. Delays + * from this function take precedence over the Reset Delay function. + * + * These _DSM functions are defined by the draft ECN of January 28, 2014, + * titled "ACPI additions for FW latency optimizations." + */ +static void pci_acpi_optimize_delay(struct pci_dev *pdev, + acpi_handle handle) +{ + struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus); + int value; + union acpi_object *obj, *elements; + + if (bridge->ignore_reset_delay) + pdev->d3cold_delay = 0; + + obj = acpi_evaluate_dsm(handle, pci_acpi_dsm_uuid, 3, + FUNCTION_DELAY_DSM, NULL); + if (!obj) + return; + + if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) { + elements = obj->package.elements; + if (elements[0].type == ACPI_TYPE_INTEGER) { + value = (int)elements[0].integer.value / 1000; + if (value < PCI_PM_D3COLD_WAIT) + pdev->d3cold_delay = value; + } + if (elements[3].type == ACPI_TYPE_INTEGER) { + value = (int)elements[3].integer.value / 1000; + if (value < PCI_PM_D3_WAIT) + pdev->d3_delay = value; + } + } + ACPI_FREE(obj); +} + static void pci_acpi_setup(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); @@ -575,6 +647,8 @@ static void pci_acpi_setup(struct device *dev) if (!adev) return; + pci_acpi_optimize_delay(pci_dev, adev->handle); + pci_acpi_add_pm_notifier(adev, pci_dev); if (!adev->wakeup.flags.valid) return; diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h index 3801c704a945..a965efa52152 100644 --- a/include/linux/pci-acpi.h +++ b/include/linux/pci-acpi.h @@ -79,6 +79,8 @@ static inline void acpiphp_check_host_bridge(struct acpi_device *adev) { } extern const u8 pci_acpi_dsm_uuid[]; #define DEVICE_LABEL_DSM 0x07 +#define RESET_DELAY_DSM 0x08 +#define FUNCTION_DELAY_DSM 0x09 #else /* CONFIG_ACPI */ static inline void acpi_pci_add_bus(struct pci_bus *bus) { } diff --git a/include/linux/pci.h b/include/linux/pci.h index 211e9da8a7d7..c5aa7b8a40c1 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -406,6 +406,7 @@ struct pci_host_bridge { struct list_head windows; /* resource_entry */ void (*release_fn)(struct pci_host_bridge *); void *release_data; + unsigned int ignore_reset_delay:1; /* for entire hierarchy */ }; #define to_pci_host_bridge(n) container_of(n, struct pci_host_bridge, dev) |