From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> As per PCI Firmware Specification, r3.2 ECN (https://members.pcisig.com/wg/PCI-SIG/document/12614), OS can use bit 7 of _OSC Control Field to negotiate control over Downstream Port Containment (DPC) configuration of PCIe port. After _OSC negotiation, firmware will Set this bit to grant OS control over PCIe DPC configuration and Clear it if this feature was requested and denied, or was not requested. Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> --- drivers/acpi/pci_root.c | 6 ++++++ drivers/pci/pcie/portdrv_core.c | 3 ++- drivers/pci/probe.c | 1 + include/linux/acpi.h | 3 ++- include/linux/pci.h | 1 + 5 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 707aafc7c2aa..a60261e50b08 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -154,6 +154,7 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = { { OSC_PCI_EXPRESS_AER_CONTROL, "AER" }, { OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" }, { OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" }, + { OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" }, }; static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word, @@ -499,6 +500,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, control |= OSC_PCI_EXPRESS_AER_CONTROL; } + if (IS_ENABLED(CONFIG_PCIE_DPC)) + control |= OSC_PCI_EXPRESS_DPC_CONTROL; + requested = control; status = acpi_pci_osc_control_set(handle, &control, OSC_PCI_EXPRESS_CAPABILITY_CONTROL); @@ -927,6 +931,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, host_bridge->native_pme = 0; if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL)) host_bridge->native_ltr = 0; + if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL)) + host_bridge->native_dpc = 0; pci_scan_child_bus(bus); pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info, diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 7d04f9d087a6..865f12f4b314 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -250,7 +250,8 @@ static int get_port_device_capability(struct pci_dev *dev) } if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) && - pci_aer_available() && services & PCIE_PORT_SERVICE_AER) + 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 || diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 2ec0df04e0dc..ef1118f70860 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -608,6 +608,7 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv) bridge->native_shpc_hotplug = 1; bridge->native_pme = 1; bridge->native_ltr = 1; + bridge->native_dpc = 1; return bridge; } diff --git a/include/linux/acpi.h b/include/linux/acpi.h index d5dcebd7aad3..f68e9513996b 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -522,7 +522,8 @@ extern bool osc_pc_lpi_support_confirmed; #define OSC_PCI_EXPRESS_AER_CONTROL 0x00000008 #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL 0x00000010 #define OSC_PCI_EXPRESS_LTR_CONTROL 0x00000020 -#define OSC_PCI_CONTROL_MASKS 0x0000003f +#define OSC_PCI_EXPRESS_DPC_CONTROL 0x00000080 +#define OSC_PCI_CONTROL_MASKS 0x000000ff #define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002 #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004 diff --git a/include/linux/pci.h b/include/linux/pci.h index 77448215ef5b..1c38bcd200d1 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -502,6 +502,7 @@ 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 native_dpc:1; /* OS may use PCIe DPC */ /* Resource alignment requirements */ resource_size_t (*align_resource)(struct pci_dev *dev, const struct resource *res, -- 2.20.1
