[PATCH v3 5/5] PCI/ACPI: Expose EDR support via _OSC to BIOS

[sathyanarayanan . kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

As per PCI Firmware Specification, r3.2 ECN
(https://members.pcisig.com/wg/PCI-SIG/document/12614), if OS supports
EDR, it should expose its support to BIOS by setting bit 7 of _OSC
Support Field.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 drivers/acpi/pci_root.c | 3 +++
 include/linux/acpi.h    | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index a60261e50b08..aeb3fcc40e2f 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -145,6 +145,7 @@ static struct pci_osc_bit_struct pci_osc_support_bit[] = {
 	{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
 	{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
 	{ OSC_PCI_MSI_SUPPORT, "MSI" },
+	{ OSC_PCI_EDR_SUPPORT, "EDR" },
 };
 
 static struct pci_osc_bit_struct pci_osc_control_bit[] = {
@@ -453,6 +454,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
 		support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
 	if (pci_msi_enabled())
 		support |= OSC_PCI_MSI_SUPPORT;
+	if (IS_ENABLED(CONFIG_PCIE_EDR))
+		support |= OSC_PCI_EDR_SUPPORT;
 
 	decode_osc_support(root, "OS supports", support);
 	status = acpi_pci_osc_support(root, support);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index f68e9513996b..c60b7d72e526 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -513,7 +513,8 @@ extern bool osc_pc_lpi_support_confirmed;
 #define OSC_PCI_CLOCK_PM_SUPPORT		0x00000004
 #define OSC_PCI_SEGMENT_GROUPS_SUPPORT		0x00000008
 #define OSC_PCI_MSI_SUPPORT			0x00000010
-#define OSC_PCI_SUPPORT_MASKS			0x0000001f
+#define OSC_PCI_EDR_SUPPORT			0x00000080
+#define OSC_PCI_SUPPORT_MASKS			0x000000ff
 
 /* PCI Host Bridge _OSC: Capabilities DWORD 3: Control Field */
 #define OSC_PCI_EXPRESS_NATIVE_HP_CONTROL	0x00000001
-- 
2.20.1