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authorGeert Uytterhoeven <geert+renesas@glider.be>2014-07-11 19:56:21 +0400
committerVinod Koul <vinod.koul@intel.com>2014-07-25 12:51:23 +0400
commit70c9b8bd7ac4931c775dab77ad29117523bf0956 (patch)
treec64a6b2770480f64012566efeb356a066ad94cdf /Documentation/dmaengine.txt
parent211bfef7c2bc8c67e3878e54747e6bb2be3456da (diff)
downloadlinux-70c9b8bd7ac4931c775dab77ad29117523bf0956.tar.xz
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.txt6
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)