[coreboot-gerrit] Change in coreboot[master]: src/cpu/x86/mtrr/earlymtrr: Add clear_all_var_mtrr

[Raul Rangel (Code Review)]

Raul Rangel has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/40764 )

Change subject: src/cpu/x86/mtrr/earlymtrr: Add clear_all_var_mtrr
......................................................................

src/cpu/x86/mtrr/earlymtrr: Add clear_all_var_mtrr

Picasso does not define the state of variable MTRRs on boot. Add a
helper function to clear all MTRRs.

BUG=b:147042464
TEST=Build trembyle

Signed-off-by: Raul E Rangel 
Change-Id: I21b887ce12849a95ddd8f1698028fb6bbfb4a7f6
---
M src/cpu/x86/mtrr/earlymtrr.c
M src/include/cpu/x86/mtrr.h
2 files changed, 15 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/64/40764/1

diff --git a/src/cpu/x86/mtrr/earlymtrr.c b/src/cpu/x86/mtrr/earlymtrr.c
index 4d14a8d..e400359 100644
--- a/src/cpu/x86/mtrr/earlymtrr.c
+++ b/src/cpu/x86/mtrr/earlymtrr.c
@@ -42,3 +42,17 @@
    maskm.hi = (1 << (cpu_phys_address_size() - 32)) - 1;
    wrmsr(MTRR_PHYS_MASK(reg), maskm);
 }
+
+void clear_all_var_mtrr(void)
+{
+	msr_t mtrr = {0, 0};
+	int vcnt;
+	int i;
+
+	vcnt = get_var_mtrr_count();
+
+	for (i = 0; i < vcnt; i++) {
+		wrmsr(MTRR_PHYS_MASK(i), mtrr);
+		wrmsr(MTRR_PHYS_BASE(i), mtrr);
+	}
+}
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h
index 07db3cb..50148ff 100644
--- a/src/include/cpu/x86/mtrr.h
+++ b/src/include/cpu/x86/mtrr.h
@@ -107,6 +107,7 @@
 void set_var_mtrr(unsigned int reg, unsigned int base, unsigned int size,
    unsigned int type);
 int get_free_var_mtrr(void);
+void clear_all_var_mtrr(void);

asmlinkage void display_mtrrs(void);