Bruce Griffith (Bruce.Griffith@se-eng.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3823
-gerrit
commit e18ab68ba589be8077070a2d3f58dee15c5d6e14 Author: Mike Loptien mike.loptien@se-eng.com Date: Thu Jul 18 10:30:47 2013 -0600
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 mike.loptien@se-eng.com --- 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 5d3a29c..06b4fe7 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 */