|author||Dave Jiang <firstname.lastname@example.org>||2016-07-20 13:14:19 -0700|
|committer||Vinod Koul <email@example.com>||2016-08-08 08:11:42 +0530|
dmaengine: documentation to the new callback mechanism
Adding documentation in dmaengine/provider.txt on the usage of callback with result, callback_result, function pointer to retrieve transanction result from a DMA submission. Signed-off-by: Dave Jiang <firstname.lastname@example.org> Reviewed-by: Lars-Peter Clausen <email@example.com> Signed-off-by: Vinod Koul <firstname.lastname@example.org>
Diffstat (limited to 'Documentation/dmaengine')
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt
index 91ce82d5f0c4..c4fd47540b31 100644
@@ -282,6 +282,17 @@ supported.
that is supposed to push the current
transaction descriptor to a pending queue, waiting
for issue_pending to be called.
+ - In this structure the function pointer callback_result can be
+ initialized in order for the submitter to be notified that a
+ transaction has completed. In the earlier code the function pointer
+ callback has been used. However it does not provide any status to the
+ transaction and will be deprecated. The result structure defined as
+ dmaengine_result that is passed in to callback_result has two fields:
+ + result: This provides the transfer result defined by
+ dmaengine_tx_result. Either success or some error
+ + residue: Provides the residue bytes of the transfer for those that
+ support residue.
- Takes the first transaction descriptor in the pending queue,