[ARM] dma: don't touch cache on dma_*_for_cpu()

As per the dma_unmap_* calls, we don't touch the cache when a DMA
buffer transitions from device to CPU ownership.  Presently, no
problems have been identified with speculative cache prefetching
which in itself is a new feature in later architectures.  We may
have to revisit the DMA API later for these architectures anyway.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 1 insertions, 5 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 2544a087c213..ad62020763f1 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -376,11 +376,7 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev,
 {
         BUG_ON(!valid_dma_direction(dir));
 
-        if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir))
-                return;
-
-        if (!arch_is_coherent())
-                dma_cache_maint(dma_to_virt(dev, handle) + offset, size, dir);
+        dmabounce_sync_for_cpu(dev, handle, offset, size, dir);
 }
 
 static inline void dma_sync_single_range_for_device(struct device *dev,