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>

diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt
index e33bc1c8ed2c44fede97ee64ca5a2a7e48389c50..bfadbfdf13ed6c04b36b425cd9358ec8c663906d 100644 (file)
--- 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 533680860865a2f6b64d0f73d3fb9040e097657b..dd4de1d4016669de3534d28475f9705b8fc48925 100644 (file)
--- 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),
 };
 
 /**