[RFC PATCH 2/4] ASoC: soc-generic-dmaengine-pcm: Add custom prepare and submit function

[Shevchenko, Andriy]

On Mon, Nov 30, 2020 at 11:45:17AM +0100, Lars-Peter Clausen wrote:
> On 11/30/20 10:57 AM, Sit, Michael Wei Hong wrote:

> > Is there anymore comment on this RFC?
> > We will be using the ASoC framework to split the linked-list, since resplitting the linked-list in DMA is a no go.
> > If there isn't any more comments, we will push these patches for review and merging.

> Why is splitting the list in the DMAengine framework a no go?
> 
> The whole idea of the DMAengine framework is to hide hardware specifics. It
> offers an API with certain semantics and it is up to the driver to provide
> an implementation that implements these semantics. There does not
> necessarily have to be a 1-to-1 mapping to hardware primitives in such an
> implementation.

I would say it's not desirable.

Why should we split than resplit if we may do it in one go?
Why then we have DMA capabilities returned to the consumers.

So, I have that we need to optimize DMA SG list preparation in a way that
consumer gets SG list cooked in accordance with DMA limitations / requirements.

-- 
With Best Regards,
Andy Shevchenko