ARMV7: add a function to disable MMU entries

It is useful to be able to lock out certain address ranges,
NULL being the most important example.

void mmu_disable_range(unsigned long start_mb, unsigned long size_mb)

will allow us to lock out selected virtual addresses on MiB boundaries.
As in other ARM mmu functions, the addresses and quantities are in units
of MiB.

Change-Id: If516ce955ee2d12c5a409f25acbb5a4b424f699b
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/3160
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/arch/armv7/include/arch/cache.h b/src/arch/armv7/include/arch/cache.h
index 028cf1808d..d5c3a5b241 100644
--- a/src/arch/armv7/include/arch/cache.h
+++ b/src/arch/armv7/include/arch/cache.h
@@ -303,6 +303,8 @@ enum dcache_policy {
 	DCACHE_WRITETHROUGH,
 };
 
+/* disable the mmu for a range. Primarily useful to lock out address 0. */
+void mmu_disable_range(unsigned long start_mb, unsigned long size_mb);
 /* mmu range configuration (set dcache policy) */
 void mmu_config_range(unsigned long start_mb, unsigned long size_mb,
 						enum dcache_policy policy);