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-rw-r--r--src/arch/armv7/include/arch/cache.h2
-rw-r--r--src/arch/armv7/lib/mmu.c13
2 files changed, 15 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);
diff --git a/src/arch/armv7/lib/mmu.c b/src/arch/armv7/lib/mmu.c
index 224b566a50..82c735818e 100644
--- a/src/arch/armv7/lib/mmu.c
+++ b/src/arch/armv7/lib/mmu.c
@@ -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)
{