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Commit 3e00ab4a authored by Abhishek Sahu's avatar Abhishek Sahu Committed by Vinod Koul
Browse files

dmaengine: add DMA_PREP_CMD for non-Data descriptors. 



Some of the DMA controllers are capable of issuing the commands
to peripheral by the DMA. These commands can be list of register
reads/writes and its different from normal data reads/writes.
This patch adds new flag DMA_PREP_CMD in DMA API which tells
the driver that the data passed to DMA API is command data
and DMA controller driver will form descriptor in the required
format.

This flag can be used by any DMA controller driver which requires
the descriptor in different format for non-Data descriptors.

Signed-off-by: default avatarAbhishek Sahu <absahu@codeaurora.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent a63efead

Documentation/dmaengine/provider.txt

+7 −0
Original line number Diff line number Diff line
@@ -395,6 +395,13 @@ where to put them) 
	  when DMA_CTRL_REUSE is already set

	- Terminating the channel



  * DMA_PREP_CMD

    - If set, the client driver tells DMA controller that passed data in DMA

      API is command data.

    - Interpretation of command data is DMA controller specific. It can be

      used for issuing commands to other peripherals/register reads/register

      writes for which the descriptor should be in different format from

      normal data descriptors.



General Design Notes

--------------------

include/linux/dmaengine.h

+4 −0
Original line number Diff line number Diff line
@@ -186,6 +186,9 @@ struct dma_interleaved_template { 
 *  on the result of this operation

 * @DMA_CTRL_REUSE: client can reuse the descriptor and submit again till

 *  cleared or freed

 * @DMA_PREP_CMD: tell the driver that the data passed to DMA API is command

 *  data and the descriptor should be in different format from normal

 *  data descriptors.

 */

enum dma_ctrl_flags {

	DMA_PREP_INTERRUPT = (1 << 0),
@@ -195,6 +198,7 @@ enum dma_ctrl_flags { 
	DMA_PREP_CONTINUE = (1 << 4),

	DMA_PREP_FENCE = (1 << 5),

	DMA_CTRL_REUSE = (1 << 6),

	DMA_PREP_CMD = (1 << 7),

};



/**