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Fixed broken MTRR for >4GB memory on AMD K8 fam 0fh rev <=E 

AMD K8 rev F and later implements a bit SYSCFG_MSR_TOM2WB to
mark dram memory above 4GB as WB. However, AMD K8
rev E and earlier don't implement this bit and therefore need
MTRR spanning dram memory above 4GB. The current implementation
of amd_setup_mtrrs never generate MTRR above 4GB.
This caused memory > 4GB not to be recognized in e.g. Linux on those
rev E or older platforms. This commit should fix that bug.

Signed-off-by: Oskar Enoksson <enok@lysator.liu.se>
Change-Id: Ie568a52a8eb355969c86964d5afc4692e60f69c1
Reviewed-on: http://review.coreboot.org/238
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>
This commit is contained in:
Oskar Enoksson 2011-10-06 18:21:19 +02:00 committed by Marc Jones
parent 75df1062a1
commit 07bf911931
1 changed files with 16 additions and 3 deletions
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19
src/cpu/amd/mtrr/amd_mtrr.c
View File

@ -112,7 +112,14 @@ void amd_setup_mtrrs(void)
struct mem_state state;
unsigned long i;
msr_t msr, sys_cfg;
// Test if this CPU is a Fam 0Fh rev. F or later
const int cpu_id = cpuid_eax(0x80000001);
const int has_tom2wb =
(((cpu_id>>8 )&0xf) > 0xf) || // Family > 0F
((((cpu_id>>8 )&0xf) == 0xf) && // Family == 0F
(((cpu_id>>16)&0xf) >= 0x4)); // Rev>=F deduced from rev tables
if(has_tom2wb)
printk(BIOS_DEBUG, "CPU is Fam 0Fh rev.F or later, using TOM2WB instead of MTRR above 4GB\n");
/* Enable the access to AMD RdDram and WrDram extension bits */
disable_cache();
@ -168,7 +175,9 @@ void amd_setup_mtrrs(void)
msr.hi = state.tomk >> 22;
msr.lo = state.tomk << 10;
wrmsr(TOP_MEM2, msr);
sys_cfg.lo |= SYSCFG_MSR_TOM2En | SYSCFG_MSR_TOM2WB;
sys_cfg.lo |= SYSCFG_MSR_TOM2En;
if(has_tom2wb)
sys_cfg.lo |= SYSCFG_MSR_TOM2WB;
}
/* zero the IORR's before we enable to prevent
@ -201,5 +210,9 @@ void amd_setup_mtrrs(void)
/* Now that I have mapped what is memory and what is not
* Setup the mtrrs so we can cache the memory.
*/
x86_setup_var_mtrrs(address_bits, 0);
// Rev. F K8 supports has SYSCFG_MSR_TOM2WB and dont need
// variable MTRR to span memory above 4GB
// Lower revisions K8 need variable MTRR over 4GB
x86_setup_var_mtrrs(address_bits, has_tom2wb ? 0 : 1);
}