Arthur Heymans has uploaded this change for review.

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cpu/intel/car/core2: Update microcode in CAR setup

This updates the BSP microcode during CAR setup.

Change-Id: I8ecd1b99e18c7e73ae47f850fdc4870751dc6e8c
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
---
M src/cpu/intel/car/core2/cache_as_ram.S
1 file changed, 28 insertions(+), 7 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/75/30775/1

diff --git a/src/cpu/intel/car/core2/cache_as_ram.S b/src/cpu/intel/car/core2/cache_as_ram.S
index 981b12d..4fb8c66 100644
--- a/src/cpu/intel/car/core2/cache_as_ram.S
+++ b/src/cpu/intel/car/core2/cache_as_ram.S
@@ -111,6 +111,17 @@
 	movl	$(~(CACHE_AS_RAM_SIZE - 1) | MTRR_PHYS_MASK_VALID), %eax
 	wrmsr
 
+	/* Cache the whole rom to fetch microcode updates */
+	movl	$MTRR_PHYS_BASE(1), %ecx
+	xorl	%edx, %edx
+	movl	$CACHE_ROM_BASE | MTRR_TYPE_WRPROT, %eax
+	wrmsr
+
+	movl	$MTRR_PHYS_MASK(1), %ecx
+	rdmsr
+	movl	$(~(CACHE_ROM_SIZE - 1) | MTRR_PHYS_MASK_VALID), %eax
+	wrmsr
+
 	post_code(0x25)
 
 	/* Enable MTRR. */
@@ -131,15 +142,17 @@
 	invd
 	movl	%eax, %cr0
 
-	/* Clear the cache memory region. This will also fill up the cache. */
-	movl	$CACHE_AS_RAM_BASE, %esi
-	movl	%esi, %edi
-	movl	$(CACHE_AS_RAM_SIZE >> 2), %ecx
-	xorl	%eax, %eax
-	rep	stosl
+#if IS_ENABLED(CONFIG_MICROCODE_UPDATE_PRE_RAM)
+update_microcode:
+	/* put the return address in %esp */
+	movl	$end_microcode_update, %esp
+	jmp	update_bsp_microcode
+end_microcode_update:
+#endif
 
+cache_xip:
 	post_code(0x26)
-	/* Enable Cache-as-RAM mode by disabling cache. */
+	/* Disable caching to set final MTRRs for speeding up XIP. */
 	movl	%cr0, %eax
 	orl	$CR0_CacheDisable, %eax
 	movl	%eax, %cr0
@@ -165,8 +178,16 @@
 	/* Enable cache. */
 	movl	%cr0, %eax
 	andl	$(~(CR0_CacheDisable | CR0_NoWriteThrough)), %eax
+	invd
 	movl	%eax, %cr0
 
+	/* Clear the cache memory region. This will also fill up the cache. */
+	movl	$CACHE_AS_RAM_BASE, %esi
+	movl	%esi, %edi
+	movl	$(CACHE_AS_RAM_SIZE >> 2), %ecx
+	xorl	%eax, %eax
+	rep	stosl
+
 	/* Setup the stack. */
 	mov	$_car_stack_end, %esp
 

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