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authorAbhishek Sahu <absahu@codeaurora.org>2017-08-01 17:11:42 +0300
committerVinod Koul <vinod.koul@intel.com>2017-08-28 14:10:18 +0300
commit3e00ab4ac51c2ed47c28fd5000c47399f1a11cf5 (patch)
tree67ced0d4b885d8a2c976545b249b014d8e4ad0eb
parenta63efead7f8eeefcf08e4e7d0b033ac552f7da23 (diff)
downloadlinux-3e00ab4ac51c2ed47c28fd5000c47399f1a11cf5.tar.xz
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: Abhishek Sahu <absahu@codeaurora.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
-rw-r--r--Documentation/dmaengine/provider.txt7
-rw-r--r--include/linux/dmaengine.h4
2 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt
index e33bc1c8ed2c..bfadbfdf13ed 100644
--- a/Documentation/dmaengine/provider.txt
+++ b/Documentation/dmaengine/provider.txt
@@ -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
--------------------
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 533680860865..dd4de1d40166 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -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),
};
/**