ARM: mm: Add strongly ordered descriptor support.

On certain architectures, there might be a need to mark certain
addresses with strongly ordered memory attributes to avoid ordering
issues at the interconnect level.

On OMAP4, the asynchronous bridge buffers can only be drained
with strongly ordered accesses and hence the need to mark the
memory strongly ordered.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Woodruff Richard <r-woodruff2@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>

3 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm/include/asm/mach/map.h b/arch/arm/include/asm/mach/map.h
index d2fedb5aeb1..b36f3654bf5 100644
--- a/arch/arm/include/asm/mach/map.h
+++ b/arch/arm/include/asm/mach/map.h
@@ -29,6 +29,7 @@ struct map_desc {
 #define MT_MEMORY_NONCACHED     11
 #define MT_MEMORY_DTCM          12
 #define MT_MEMORY_ITCM          13
+#define MT_MEMORY_SO            14
 
 #ifdef CONFIG_MMU
 extern void iotable_init(struct map_desc *, int);
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 5750704e027..f1956b27ae5 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -232,6 +232,9 @@ extern pgprot_t		pgprot_kernel;
 #define pgprot_writecombine(prot) \
         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE)
 
+#define pgprot_stronglyordered(prot) \
+        __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED)
+
 #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
 #define pgprot_dmacoherent(prot) \
         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE | L_PTE_XN)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 594d677b92c..ea9c9f3e48b 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -273,6 +273,14 @@ static struct mem_type mem_types[] = {
                 .prot_l1   = PMD_TYPE_TABLE,
                 .domain    = DOMAIN_KERNEL,
         },
+        [MT_MEMORY_SO] = {
+                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
+                                L_PTE_MT_UNCACHED,
+                .prot_l1   = PMD_TYPE_TABLE,
+                .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_S |
+                                PMD_SECT_UNCACHED | PMD_SECT_XN,
+                .domain    = DOMAIN_KERNEL,
+        },
 };
 
 const struct mem_type *get_mem_type(unsigned int type)