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| author | Dave Jiang <dave.jiang@intel.com> | 2016-07-20 13:14:19 -0700 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2016-08-08 08:11:42 +0530 |
| commit | 9686218982709122373b755c9d7457bed0872999 (patch) | |
| tree | b74280f2e713dfdc2fed814bc2636980abd0f2d6 | |
| parent | 72203572afd7aef243c182f19925e5a77a1dc6a1 (diff) | |
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 <dave.jiang@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| -rw-r--r-- | Documentation/dmaengine/provider.txt | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index 91ce82d5f0c4..c4fd47540b31 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt @@ -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 + condition. + + residue: Provides the residue bytes of the transfer for those that + support residue. * device_issue_pending - Takes the first transaction descriptor in the pending queue, |