From 309dbbabee7b19e003e1ba4b98f43d28f390a84e Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 29 Sep 2008 19:50:59 +0100 Subject: [PATCH] [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 --- arch/arm/include/asm/dma-mapping.h | 6 +----- arch/arm/mm/dma-mapping.c | 8 ++------ 2 files changed, 3 insertions(+), 11 deletions(-) diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index 2544a087c21..ad62020763f 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, diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 0e28cf33f7d..67960017dc8 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -585,12 +585,8 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int i; for_each_sg(sg, s, nents, i) { - if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0, - sg_dma_len(s), dir)) - continue; - - if (!arch_is_coherent()) - dma_cache_maint(sg_virt(s), s->length, dir); + dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0, + sg_dma_len(s), dir); } } EXPORT_SYMBOL(dma_sync_sg_for_cpu); -- 2.41.0