diff options
| -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: | |||
| 100 | The peripheral driver is expected to have mapped the scatterlist for | 100 | The peripheral driver is expected to have mapped the scatterlist for |
| 101 | the DMA operation prior to calling device_prep_slave_sg, and must | 101 | the DMA operation prior to calling device_prep_slave_sg, and must |
| 102 | keep the scatterlist mapped until the DMA operation has completed. | 102 | keep the scatterlist mapped until the DMA operation has completed. |
| 103 | The scatterlist must be mapped using the DMA struct device. So, | 103 | The scatterlist must be mapped using the DMA struct device. |
| 104 | normal setup should look like this: | 104 | If a mapping needs to be synchronized later, dma_sync_*_for_*() must be |
| 105 | called using the DMA struct device, too. | ||
| 106 | So, normal setup should look like this: | ||
| 105 | 107 | ||
| 106 | nr_sg = dma_map_sg(chan->device->dev, sgl, sg_len); | 108 | nr_sg = dma_map_sg(chan->device->dev, sgl, sg_len); |
| 107 | if (nr_sg == 0) | 109 | if (nr_sg == 0) |