Patch set updated for coreboot: WIP: soc/intel/apollolake: Change default CAR size to 768 KiB

[Andrey Petrov]

Andrey Petrov ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/15453

-gerrit

commit c01491d37ceda5922d5c309cc57624ecf7a1697a
Author: Andrey Petrov <[e-mail]>
Date:   Mon Jun 27 15:21:26 2016 -0700

    WIP: soc/intel/apollolake: Change default CAR size to 768 KiB
    
    As whole 1024 KiB is not used, it is possible to shrink CAR size
    to 768 KiB. Since 768 KiB is not power of two, 2 MTRRs are used
    to setup it. This is part of preparation for CQOS enabling.
    
    BUG=chrome-os-partner:51959
    
    Change-Id: I56326a1790df202a0e428e092dd90286c58763c5
    Signed-off-by: Andrey Petrov <[e-mail]>
---
 src/soc/intel/apollolake/Kconfig                  |  2 +-
 src/soc/intel/apollolake/bootblock/cache_as_ram.S | 27 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig
index 98ce7d8..f51dbfb 100644
--- a/src/soc/intel/apollolake/Kconfig
+++ b/src/soc/intel/apollolake/Kconfig
@@ -77,7 +77,7 @@ config DCACHE_RAM_BASE
 
 config DCACHE_RAM_SIZE
 	hex "Length in bytes of cache-as-RAM"
-	default 0x100000
+	default 0xc0000
 	help
 	  The size of the cache-as-ram region required during bootblock
 	  and/or romstage.
diff --git a/src/soc/intel/apollolake/bootblock/cache_as_ram.S b/src/soc/intel/apollolake/bootblock/cache_as_ram.S
index 8647206..8436d51 100644
--- a/src/soc/intel/apollolake/bootblock/cache_as_ram.S
+++ b/src/soc/intel/apollolake/bootblock/cache_as_ram.S
@@ -17,6 +17,7 @@
  */
 
 #include <device/pci_def.h>
+#include <commonlib/helpers.h>
 #include <cpu/x86/mtrr.h>
 #include <cpu/x86/cache.h>
 #include <cpu/x86/cr.h>
@@ -70,6 +71,7 @@ clear_var_mtrr:
 
 	post_code(0x24)
 
+#if ((CONFIG_DCACHE_RAM_SIZE & (CONFIG_DCACHE_RAM_SIZE - 1)) == 0)
 	/* Configure CAR region as write-back (WB) */
 	mov	$MTRR_PHYS_BASE(0), %ecx
 	mov	$CONFIG_DCACHE_RAM_BASE, %eax
@@ -82,6 +84,31 @@ clear_var_mtrr:
 	mov	$~(CONFIG_DCACHE_RAM_SIZE - 1), %eax	/* size mask */
 	or	$MTRR_PHYS_MASK_VALID, %eax
 	wrmsr
+#elif (CONFIG_DCACHE_RAM_SIZE == 768 * KiB) /* 768 KiB */
+	mov	$MTRR_PHYS_BASE(0), %ecx
+	mov	$CONFIG_DCACHE_RAM_BASE, %eax
+	or	$MTRR_TYPE_WRBACK, %eax
+	xor	%edx,%edx
+	wrmsr
+
+	mov	$MTRR_PHYS_MASK(0), %ecx
+	mov	$~(512 * KiB - 1), %eax	/* size mask */
+	or	$MTRR_PHYS_MASK_VALID, %eax
+	wrmsr
+
+	mov	$MTRR_PHYS_BASE(1), %ecx
+	mov	$(CONFIG_DCACHE_RAM_BASE + 512 * KiB), %eax
+	or	$MTRR_TYPE_WRBACK, %eax
+	xor	%edx,%edx
+	wrmsr
+
+	mov	$MTRR_PHYS_MASK(1), %ecx
+	mov	$~(0x256 * KiB - 1), %eax	/* size mask */
+	or	$MTRR_PHYS_MASK_VALID, %eax
+	wrmsr
+#else
+#error "CONFIG_DCACHE_RAM_SIZE is not power of 2 and no matching mtrr set up code"
+#endif
 
 	post_code(0x25)