AMD Fam16: Add secondary bus number to CRES method

Adding the 'WordBusNumber' macro to the PCI0
CRES ResourceTemplate in the AMD FCH ACPI code.
This sets up the bus number for the PCI0 device
and the secondary bus number in the CRS method.
This change came in response to a 'dmesg' error
which states:
'[FIRMWARE BUG]: ACPI: no secondary bus range in _CRS'

By adding the 'WordBusNumber' macro, ACPI can set
up a valid range for the PCIe downstream busses,
thereby relieving the Linux kernel from "guessing"
the valid range based off _BBN or assuming [0-0xFF].
The Linux kernel code that checks this bus range is
in `drivers/acpi/pci_root.c`.  PCI busses can have
up to 256 secondary busses connected to them via
a PCI-PCI bridge.  However, these busses do not
have to be sequentially numbered, so leaving out a
section of the range (eg. allowing [0-0x7F]) will
unnecessarily restrict the downstream busses.

Change-Id: Ib2d36f69a26b715798ef1ea17deb0905fa0cad87
Signed-off-by: Mike Loptien <mike.loptien@se-eng.com>
Reviewed-on: http://review.coreboot.org/3822
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/src/southbridge/amd/agesa/hudson/acpi/fch.asl b/src/southbridge/amd/agesa/hudson/acpi/fch.asl
index 4fbf853038..5d3a29ce5c 100755
--- a/src/southbridge/amd/agesa/hudson/acpi/fch.asl
+++ b/src/southbridge/amd/agesa/hudson/acpi/fch.asl
@@ -71,6 +71,22 @@ Device(ACMD) {
 #endif
 
 Name(CRES, ResourceTemplate() {
+	/* Set the Bus number and Secondary Bus number for the PCI0 device
+	 * The Secondary bus range for PCI0 lets the system
+	 * know what bus values are allowed on the downstream
+	 * side of this PCI bus if there is a PCI-PCI bridge.
+	 * PCI busses can have 256 secondary busses which
+	 * range from [0-0xFF] but they do not need to be
+	 * sequential.
+	 */
+	WordBusNumber (ResourceProducer, MinFixed, MaxFixed, PosDecode,
+		0x0000,		/* address granularity */
+		0x0000,		/* range minimum */
+		0x00FF,		/* range maximum */
+		0x0000,		/* translation */
+		0x0100,		/* length */
+		,, PSB0)		/* ResourceSourceIndex, ResourceSource, DescriptorName */
+
 	IO(Decode16, 0x0CF8, 0x0CF8, 1,	8)
 
 	WORDIO(ResourceProducer, MinFixed, MaxFixed, PosDecode, EntireRange,