fsldma: improved DMA_SLAVE support

Now that the generic DMAEngine API has support for scatterlist to
scatterlist copying, the device_prep_slave_sg() portion of the
DMA_SLAVE API is no longer necessary and has been removed.

However, the device_control() portion of the DMA_SLAVE API is still
useful to control device specific parameters, such as externally
controlled DMA transfers and maximum burst length.

A special dma_ctrl_cmd has been added to enable externally controlled
DMA transfers. This is currently specific to the Freescale DMA
controller, but can easily be made generic when another user is found.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 2c9ee98f6c77..885f35211675 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -120,12 +120,15 @@ enum dma_ctrl_flags {
  * configuration data in statically from the platform). An additional
  * argument of struct dma_slave_config must be passed in with this
  * command.
+ * @FSLDMA_EXTERNAL_START: this command will put the Freescale DMA controller
+ * into external start mode.
  */
 enum dma_ctrl_cmd {
         DMA_TERMINATE_ALL,
         DMA_PAUSE,
         DMA_RESUME,
         DMA_SLAVE_CONFIG,
+        FSLDMA_EXTERNAL_START,
 };
 
 /**