[coreboot] [PATCH] let fam10 machines calculate correct link offsets
Maximilian Thuermer
Maximilian.Thuermer at ziti.uni-heidelberg.de
Thu Mar 18 17:43:44 CET 2010
Hi all,
I am working with a Tyan S2912 board and fam10 Opterons and
recently updated my coreboot environment. I stumbled across
an error which I thought was already removed a while ago.
The HT link offsets reported by function "AMD_CpuFindCapability" in
init_cpus.c
are not correct (they always evaluate to 0x08) and therefore do not
comply with link offsets as specified by AMDs BKDG.
Below is a simple fix which produces correct behavior - at least on my box.
Dont know what side effects this might have on systems other than the PHY
electrical settings and erratas not getting applied.
Best regards,
Maximilian Thuermer
Index: src/cpu/amd/model_10xxx/init_cpus.c
===================================================================
--- src/cpu/amd/model_10xxx/init_cpus.c (revision 5256)
+++ src/cpu/amd/model_10xxx/init_cpus.c (working copy)
@@ -702,29 +702,32 @@
*/
BOOL AMD_CpuFindCapability (u8 node, u8 cap_count, u8 *offset)
{
+ u32 reg;
u32 val;
-
+
/* get start of CPU HT Host Capabilities */
val = pci_read_config32(NODE_PCI(node, 0), 0x34);
- val &= 0xFF;
+ val &= 0xFF; //reg offset of first link
cap_count++;
/* Traverse through the capabilities. */
do {
- val = pci_read_config32(NODE_PCI(node, 0), val);
+ reg = pci_read_config32(NODE_PCI(node, 0), val);
/* Is the capability block a HyperTransport capability
block? */
- if ((val & 0xFF) == 0x08) {
+ if ((reg & 0xFF) == 0x08) {
/* Is the HT capability block an HT Host
Capability? */
- if ((val & 0xE0000000) == (1 << 29))
+ if ((reg & 0xE0000000) == (1 << 29))
cap_count--;
}
- if (cap_count)
- val = (val >> 8) & 0xFF;
+
+ if(cap_count)
+ val = (reg >> 8) & 0xFF; //update reg offset
} while (cap_count && val);
*offset = (u8) val;
+
/* If requested capability found val != 0 */
if (!cap_count)
return TRUE;
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