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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2014-07-11 17:56:21 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2014-07-25 14:21:23 +0530 |
| commit | 70c9b8bd7ac4931c775dab77ad29117523bf0956 (patch) | |
| tree | c64a6b2770480f64012566efeb356a066ad94cdf /Documentation/dmaengine.txt | |
| parent | 211bfef7c2bc8c67e3878e54747e6bb2be3456da (diff) | |
| download | lwn-70c9b8bd7ac4931c775dab77ad29117523bf0956.tar.gz lwn-70c9b8bd7ac4931c775dab77ad29117523bf0956.zip | |
dmaengine: Clarify device parameter for dma_sync_*_for_*()
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'Documentation/dmaengine.txt')
| -rw-r--r-- | Documentation/dmaengine.txt | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/Documentation/dmaengine.txt b/Documentation/dmaengine.txt index 2def665baf6e..573e28ce9751 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) |