Commit db693ade authored by Federico Vaga's avatar Federico Vaga Committed by Jonathan Corbet

doc:dmaengine: clarify DMA desc. pointer after submission

It clarifies that the DMA description pointer returned by
`dmaengine_prep_*` function should not be used after submission.
Signed-off-by: default avatarFederico Vaga <federico.vaga@cern.ch>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 2c71d305
...@@ -168,6 +168,13 @@ The details of these operations are: ...@@ -168,6 +168,13 @@ The details of these operations are:
dmaengine_submit() will not start the DMA operation, it merely adds dmaengine_submit() will not start the DMA operation, it merely adds
it to the pending queue. For this, see step 5, dma_async_issue_pending. it to the pending queue. For this, see step 5, dma_async_issue_pending.
.. note::
After calling ``dmaengine_submit()`` the submitted transfer descriptor
(``struct dma_async_tx_descriptor``) belongs to the DMA engine.
Consequentially, the client must consider invalid the pointer to that
descriptor.
5. Issue pending DMA requests and wait for callback notification 5. Issue pending DMA requests and wait for callback notification
The transactions in the pending queue can be activated by calling the The transactions in the pending queue can be activated by calling the
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment