[PATCH v3 6/7] ARM: NOMMU: Set ARM_DMA_MEM_BUFFERABLE for M-class cpus

From: Vladimir Murzin
Date: Fri Mar 10 2017 - 05:50:31 EST

Now, we have dedicated non-cacheable region for consistent DMA
operations. However, that region can still be marked as bufferable by
MPU, so it'd be safer to have barriers by default.

Tested-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
Tested-by: Andras Szemzo <sza@xxxxxx>
Tested-by: Alexandre TORGUE <alexandre.torgue@xxxxxx>
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Vladimir Murzin <vladimir.murzin@xxxxxxx>
arch/arm/mm/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index d731f28..7dd46ae 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -1050,7 +1050,7 @@ config ARM_L1_CACHE_SHIFT

bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K) && !CPU_V7
- default y if CPU_V6 || CPU_V6K || CPU_V7
+ default y if CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M
Historically, the kernel has used strongly ordered mappings to
provide DMA coherent memory. With the advent of ARMv7, mapping