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authorMarek Szyprowski <m.szyprowski@samsung.com>2012-02-10 19:55:20 +0100
committerMarek Szyprowski <m.szyprowski@samsung.com>2012-05-21 15:06:13 +0200
commita227fb92a0f5f0dd8282719386e9b3a29f0d16b2 (patch)
treeb990f647dcb38e17a4eef63b14f3358e6698e5c3 /arch/arm/mm
parent553ac78877242b6d8b591323731df304140d0f99 (diff)
ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops
This patch removes the need for the offset parameter in dma bounce functions. This is required to let dma-mapping framework on ARM architecture to use common, generic dma_map_ops based dma-mapping helpers. Background and more detailed explaination: dma_*_range_* functions are available from the early days of the dma mapping api. They are the correct way of doing a partial syncs on the buffer (usually used by the network device drivers). This patch changes only the internal implementation of the dma bounce functions to let them tunnel through dma_map_ops structure. The driver api stays unchanged, so driver are obliged to call dma_*_range_* functions to keep code clean and easy to understand. The only drawback from this patch is reduced detection of the dma api abuse. Let us consider the following code: dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE); dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE); Without the patch such code fails, because dma bounce code is unable to find the bounce buffer for the given dma_address. After the patch the above sync call will be equivalent to: dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE); which succeeds. I don't consider this as a real problem, because DMA API abuse should be caught by debug_dma_* function family. This patch lets us to simplify the internal low-level implementation without chaning the driver visible API. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> Tested-By: Subash Patel <subash.ramaswamy@linaro.org>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/dma-mapping.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index e4ac5fc86b0a..a16993a5b7eb 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -660,7 +660,7 @@ 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,
+ if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s),
sg_dma_len(s), dir))
continue;
@@ -686,7 +686,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int i;
for_each_sg(sg, s, nents, i) {
- if (!dmabounce_sync_for_device(dev, sg_dma_address(s), 0,
+ if (!dmabounce_sync_for_device(dev, sg_dma_address(s),
sg_dma_len(s), dir))
continue;