From: Paul Walmsley <paul@xxxxxxxxx>
Add a Non-cacheable Normal ARM executable memory type,
MT_MEMORY_NONCACHED. This is needed for the OMAP3 SDRAM clock change
code, which must run from SRAM. The SRAM must be marked as
non-cacheable memory to avoid dirty cache line writebacks to SDRAM
while the SDRAM controller is paused.
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/include/asm/mach/map.h | 1 +
arch/arm/mm/mmu.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/arch/arm/include/asm/mach/map.h b/arch/arm/include/asm/mach/map.h
index 39d949b..58cf91f 100644
--- a/arch/arm/include/asm/mach/map.h
+++ b/arch/arm/include/asm/mach/map.h
@@ -26,6 +26,7 @@ struct map_desc {
#define MT_HIGH_VECTORS 8
#define MT_MEMORY 9
#define MT_ROM 10
+#define MT_MEMORY_NONCACHED 11
#ifdef CONFIG_MMU
extern void iotable_init(struct map_desc *, int);
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 7f36c82..9ad6413 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -242,6 +242,10 @@ static struct mem_type mem_types[] = {
.prot_sect = PMD_TYPE_SECT,
.domain = DOMAIN_KERNEL,
},
+ [MT_MEMORY_NONCACHED] = {
+ .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
+ .domain = DOMAIN_KERNEL,
+ },
};
const struct mem_type *get_mem_type(unsigned int type)
@@ -405,9 +409,28 @@ static void __init build_mem_type_table(void)
kern_pgprot |= L_PTE_SHARED;
vecs_pgprot |= L_PTE_SHARED;
mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
+ mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
#endif
}
+ /*
+ * Non-cacheable Normal - intended for memory areas that must
+ * not cause cache line evictions when used
+ */
+ if (cpu_arch >= CPU_ARCH_ARMv6) {
+ if (cpu_arch >= CPU_ARCH_ARMv7 && (cr & CR_TRE)) {
+ /* Non-cacheable Normal is XCB = 001 */
+ mem_types[MT_MEMORY_NONCACHED].prot_sect |=
+ PMD_SECT_BUFFERED;
+ } else {
+ /* For both ARMv6 and non-TEX-remapping ARMv7 */
+ mem_types[MT_MEMORY_NONCACHED].prot_sect |=
+ PMD_SECT_TEX(1);
+ }
+ } else {
+ mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_BUFFERABLE;
+ }
+
for (i = 0; i < 16; i++) {
unsigned long v = pgprot_val(protection_map[i]);
protection_map[i] = __pgprot(v | user_pgprot);
--
1.5.4.3
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