[RFC PATCH 2/3] ARM: NOMMU: set ARM_DMA_MEM_BUFFERABLE for M-class cpus
Vladimir Murzin
vladimir.murzin at arm.com
Tue Dec 13 01:02:20 PST 2016
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.
Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
---
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 6dffbe4..7f0000d 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -1023,7 +1023,7 @@ config ARM_L1_CACHE_SHIFT
config ARM_DMA_MEM_BUFFERABLE
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
help
Historically, the kernel has used strongly ordered mappings to
provide DMA coherent memory. With the advent of ARMv7, mapping
--
1.7.9.5
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