diff options
Diffstat (limited to 'Documentation/dmaengine.txt')
| -rw-r--r-- | Documentation/dmaengine.txt | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/Documentation/dmaengine.txt b/Documentation/dmaengine.txt index 879b6e31e2da..573e28ce9751 100644 --- a/Documentation/dmaengine.txt +++ b/Documentation/dmaengine.txt @@ -84,31 +84,32 @@ The slave DMA usage consists of following steps: the given transaction. Interface: - struct dma_async_tx_descriptor *(*chan->device->device_prep_slave_sg)( + struct dma_async_tx_descriptor *dmaengine_prep_slave_sg( struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, enum dma_data_direction direction, unsigned long flags); - struct dma_async_tx_descriptor *(*chan->device->device_prep_dma_cyclic)( + struct dma_async_tx_descriptor *dmaengine_prep_dma_cyclic( struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_data_direction direction); - struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)( + struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma( struct dma_chan *chan, struct dma_interleaved_template *xt, unsigned long flags); 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) /* error */ - desc = chan->device->device_prep_slave_sg(chan, sgl, nr_sg, - direction, flags); + desc = dmaengine_prep_slave_sg(chan, sgl, nr_sg, direction, flags); Once a descriptor has been obtained, the callback information can be added and the descriptor must then be submitted. Some DMA engine @@ -188,7 +189,7 @@ Further APIs: description of this API. This can be used in conjunction with dma_async_is_complete() and - the cookie returned from 'descriptor->submit()' to check for + the cookie returned from dmaengine_submit() to check for completion of a specific DMA transaction. Note: |