Re: [PATCH] [RFC] dmaengine: add fifo_size member

From: Vinod Koul
Date: Fri Jul 19 2019 - 01:06:14 EST


On 05-07-19, 11:45, Sameer Pujar wrote:
> Hi Vinod,
>
> What are your final thoughts regarding this?

Hi sameer,

Sorry for the delay in replying

On this, I am inclined to think that dma driver should not be involved.
The ADMAIF needs this configuration and we should take the path of
dma_router for this piece and add features like this to it

>
> Thanks,
> Sameer.
>
> > > Where does ADMAIF driver reside in kernel, who configures it for normal
> > > dma txns..?
> > Not yet, we are in the process of upstreaming ADMAIF driver.
> > To describe briefly, audio subsystem is using ALSA SoC(ASoC) layer.
> > ADMAIF is
> > registered as platform driver and exports DMA functionality. It
> > registers PCM
> > devices for each Rx/Tx ADMAIF channel. During PCM playback/capture
> > operations,
> > ALSA callbacks configure DMA channel using API dmaengine_slave_config().
> > RFC patch proposed, is to help populate FIFO_SIZE value as well during
> > above
> > call, since ADMA requires it.
> > >
> > > Also it wold have helped the long discussion if that part was made clear
> > > rather than talking about peripheral all this time :(
> > Thought it was clear, though should have avoided using 'peripheral' in
> > the
> > discussions. Sorry for the confusion.

--
~Vinod