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PCI/ACPI: Evaluate PCI Boot Configuration _DSM

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Evaluate _DSM Function #5, the "PCI Boot Configuration" function.  If the
result is 0, the OS should preserve any resource assignments made by the
firmware.

Link: https://lore.kernel.org/r/20190615002359.29577-2-benh@kernel.crashing.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Benjamin Herrenschmidt 2019-06-15 10:23:57 +10:00 committed by Bjorn Helgaas
parent a188339ca5
commit a78cf9657b
3 changed files with 18 additions and 3 deletions
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12
drivers/acpi/pci_root.c
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@ -894,6 +894,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
int node = acpi_get_node(device->handle);
struct pci_bus *bus;
struct pci_host_bridge *host_bridge;
union acpi_object *obj;
info->root = root;
info->bridge = device;
@ -930,6 +931,17 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
host_bridge->native_ltr = 0;
/*
* Evaluate the "PCI Boot Configuration" _DSM Function. If it
* exists and returns 0, we must preserve any PCI resource
* assignments made by firmware for this host bridge.
*/
obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1,
IGNORE_PCI_BOOT_CONFIG_DSM, NULL);
if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0)
host_bridge->preserve_config = 1;
ACPI_FREE(obj);
pci_scan_child_bus(bus);
pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,
info);

7
include/linux/pci-acpi.h
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@ -107,9 +107,10 @@ static inline void acpiphp_check_host_bridge(struct acpi_device *adev) { }
#endif
extern const guid_t pci_acpi_dsm_guid;
#define DEVICE_LABEL_DSM 0x07
#define RESET_DELAY_DSM 0x08
#define FUNCTION_DELAY_DSM 0x09
#define IGNORE_PCI_BOOT_CONFIG_DSM 0x05
#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) { }

2
include/linux/pci.h
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@ -505,6 +505,8 @@ struct pci_host_bridge {
unsigned int native_shpc_hotplug:1; /* OS may use SHPC hotplug */
unsigned int native_pme:1; /* OS may use PCIe PME */
unsigned int native_ltr:1; /* OS may use PCIe LTR */
unsigned int preserve_config:1; /* Preserve FW resource setup */
/* Resource alignment requirements */
resource_size_t (*align_resource)(struct pci_dev *dev,
const struct resource *res,