Author: sduplichan Date: Thu Feb 10 21:49:56 2011 New Revision: 6342 URL: https://tracker.coreboot.org/trac/coreboot/changeset/6342
Log: According to AMD documentation, cache type WP should be used for execution from flash memory. Coreboot uses WB. While there is no noticeable performance difference between the two settings, use of WB can cause a problem for a jtag debugger. The attached patch changes AMD cache as ram setting for flash execution from WB to WP.
Signed-off-by: Scott Duplichan scott@notabs.org Acked-by: Marc Jones marcj303@gmail.com
Modified: trunk/src/cpu/amd/car/cache_as_ram.inc
Modified: trunk/src/cpu/amd/car/cache_as_ram.inc ============================================================================== --- trunk/src/cpu/amd/car/cache_as_ram.inc Thu Feb 10 09:49:57 2011 (r6341) +++ trunk/src/cpu/amd/car/cache_as_ram.inc Thu Feb 10 21:49:56 2011 (r6342) @@ -294,11 +294,11 @@ xorl %edx, %edx /* * IMPORTANT: The two lines below can _not_ be written like this: - * movl $(REAL_XIP_ROM_BASE | MTRR_TYPE_WRBACK), %eax + * movl $(REAL_XIP_ROM_BASE | MTRR_TYPE_WRPROT), %eax * http://www.coreboot.org/pipermail/coreboot/2010-October/060855.html */ movl $REAL_XIP_ROM_BASE, %eax - orl $MTRR_TYPE_WRBACK, %eax + orl $MTRR_TYPE_WRPROT, %eax wrmsr
movl $MTRRphysMask_MSR(1), %ecx