From 9e8690b43f4978760ba9464ffdd63d36506fc06a Mon Sep 17 00:00:00 2001 From: Mike Loptien Date: Thu, 18 Jul 2013 10:30:47 -0600 Subject: AMD Fam16: Add OSC method to PCI0 The _OSC method is used to tell the OS what capabilities it can take control over from the firmware. This method is described in chapter 6.2.9 of the ACPI spec v3.0. The method takes 4 inputs (UUID, Rev ID, Input Count, and Capabilities Buffer) and returns a Capabilites Buffer the same size as the input Buffer. This Buffer is generally 3 Dwords long consisting of an Errors Dword, a Supported Capabilities Dword, and a Control Dword. The OS will request control of certain capabilities and the firmware must grant or deny control of those features. We do not want to have control over anything so let the OS control as much as it can. The _OSC method is required for PCIe devices. During Linux boot, an error is logged to dmesg if _OSC is not found. Change-Id: Icf6e7a82284d03d23fd30ee7b7db17754e988c9a Signed-off-by: Mike Loptien Reviewed-on: http://review.coreboot.org/3823 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel --- src/southbridge/amd/agesa/hudson/acpi/fch.asl | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/src/southbridge/amd/agesa/hudson/acpi/fch.asl b/src/southbridge/amd/agesa/hudson/acpi/fch.asl index 5d3a29ce5c..06b4fe7fd1 100755 --- a/src/southbridge/amd/agesa/hudson/acpi/fch.asl +++ b/src/southbridge/amd/agesa/hudson/acpi/fch.asl @@ -21,6 +21,25 @@ /* South Bridge */ /* _SB.PCI0 */ +/* Operating System Capabilities Method */ +Method(_OSC,4) +{ + // Create DWord-addressable fields from the Capabilities Buffer + CreateDWordField(Arg3,0,CDW1) + CreateDWordField(Arg3,4,CDW2) + CreateDWordField(Arg3,8,CDW3) + + /* Check for proper PCI/PCIe UUID */ + If(LEqual(Arg0,ToUUID("33DB4D5B-1FF7-401C-9657-7441C03DD766"))) + { + /* Let OS control everything */ + Return (Arg3) + } Else { + Or(CDW1,4,CDW1) // Unrecognized UUID + Return(Arg3) + } +} + /* Describe the Southbridge devices */ /* 0:11.0 - SATA */ -- cgit v1.2.3