Messages in this thread Patch in this message | | | From | Geert Uytterhoeven <> | Subject | [PATCH v2 1/2] dmaengine: Clarify device parameter for dma_sync_*_for_*() | Date | Fri, 11 Jul 2014 17:56:21 +0200 |
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Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- v2: - New --- Documentation/dmaengine.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/Documentation/dmaengine.txt b/Documentation/dmaengine.txt index 879b6e31e2da..87d3f192e160 100644 --- a/Documentation/dmaengine.txt +++ b/Documentation/dmaengine.txt @@ -100,8 +100,10 @@ The slave DMA usage consists of following steps: The peripheral driver is expected to have mapped the scatterlist for the DMA operation prior to calling device_prep_slave_sg, and must keep the scatterlist mapped until the DMA operation has completed. - The scatterlist must be mapped using the DMA struct device. So, - normal setup should look like this: + The scatterlist must be mapped using the DMA struct device. + If a mapping needs to be synchronized later, dma_sync_*_for_*() must be + called using the DMA struct device, too. + So, normal setup should look like this: nr_sg = dma_map_sg(chan->device->dev, sgl, sg_len); if (nr_sg == 0) -- 1.9.1
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