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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>
This commit is contained in:
Ronald G. Minnich 2013-04-30 10:11:30 -07:00 committed by David Hendricks
parent 043b823a73
commit c0466d46b7
2 changed files with 15 additions and 0 deletions
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2
src/arch/armv7/include/arch/cache.h
View File

@ -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);

13
src/arch/armv7/lib/mmu.c
View File

@ -39,6 +39,19 @@
static uintptr_t ttb_addr;
void mmu_disable_range(unsigned long start_mb, unsigned long size_mb)
{
unsigned int i;
uint32_t *ttb_entry = (uint32_t *)ttb_addr;
printk(BIOS_DEBUG, "Disabling: 0x%08lx:0x%08lx\n",
start_mb << 20, ((start_mb + size_mb) << 20) - 1);
for (i = start_mb; i < start_mb + size_mb; i++) {
ttb_entry[i] = 0;
tlbimvaa(i);
}
}
void mmu_config_range(unsigned long start_mb, unsigned long size_mb,
enum dcache_policy policy)
{