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x86: Setup fixed range MTRRs for legacy regions 

We should setup fixed range MTRRs for some legacy regions like VGA
RAM and PCI ROM areas as uncacheable. Note FSP may setup these to
other cache settings, but we can override this in x86_cpu_init_f().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Bin Meng 2015-07-06 16:31:30 +08:00 committed by Simon Glass
parent 0e98a1473a
commit 43dd22f5fc
2 changed files with 38 additions and 11 deletions
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22
arch/x86/cpu/cpu.c
View File

@ -28,6 +28,8 @@
#include <asm/cpu.h> #include <asm/cpu.h>
#include <asm/lapic.h> #include <asm/lapic.h>
#include <asm/mp.h> #include <asm/mp.h>
#include <asm/msr.h>
#include <asm/mtrr.h>
#include <asm/post.h> #include <asm/post.h>
#include <asm/processor.h> #include <asm/processor.h>
#include <asm/processor-flags.h> #include <asm/processor-flags.h>
@ -352,6 +354,26 @@ int x86_cpu_init_f(void)
gd->arch.has_mtrr = has_mtrr(); gd->arch.has_mtrr = has_mtrr();
} }
/* Configure fixed range MTRRs for some legacy regions */
if (gd->arch.has_mtrr) {
u64 mtrr_cap;
mtrr_cap = native_read_msr(MTRR_CAP_MSR);
if (mtrr_cap & MTRR_CAP_FIX) {
/* Mark the VGA RAM area as uncacheable */
native_write_msr(MTRR_FIX_16K_A0000_MSR, 0, 0);
/* Mark the PCI ROM area as uncacheable */
native_write_msr(MTRR_FIX_4K_C0000_MSR, 0, 0);
native_write_msr(MTRR_FIX_4K_C8000_MSR, 0, 0);
native_write_msr(MTRR_FIX_4K_D0000_MSR, 0, 0);
native_write_msr(MTRR_FIX_4K_D8000_MSR, 0, 0);
/* Enable the fixed range MTRRs */
msr_setbits_64(MTRR_DEF_TYPE_MSR, MTRR_DEF_TYPE_FIX_EN);
}
}
return 0; return 0;
} }

5
arch/x86/include/asm/mtrr.h
View File

@ -21,6 +21,11 @@
#define MTRR_CAP_MSR 0x0fe #define MTRR_CAP_MSR 0x0fe
#define MTRR_DEF_TYPE_MSR 0x2ff #define MTRR_DEF_TYPE_MSR 0x2ff
#define MTRR_CAP_SMRR (1 << 11)
#define MTRR_CAP_WC (1 << 10)
#define MTRR_CAP_FIX (1 << 8)
#define MTRR_CAP_VCNT_MASK 0xff
#define MTRR_DEF_TYPE_EN (1 << 11) #define MTRR_DEF_TYPE_EN (1 << 11)
#define MTRR_DEF_TYPE_FIX_EN (1 << 10) #define MTRR_DEF_TYPE_FIX_EN (1 << 10)