Re: [PATCH 1/2] dma: tegra: set DMA_CYCLIC capability

[Laxman Dewangan]

On Wednesday 27 June 2012 06:59 PM, Vinod Koul wrote:
> On Fri, 2012-06-22 at 17:12 +0530, Laxman Dewangan wrote:
> > Tegra's APB DMA driver support the cyclic mode of data
> > transfer and hence setting the DMA_CYCLIC caps for dma
> > channels.
> >
> > This is require when generic sound dmaengine pcm driver
> > request for dma channel with CYCLIC capability.
> >
> > Signed-off-by: Laxman Dewangan<ldewangan@xxxxxxxxxx>
> > ---
> >   drivers/dma/tegra20-apb-dma.c |    2 ++
> >   1 files changed, 2 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> > index 134ea7c..b4bd50c 100644
> > --- a/drivers/dma/tegra20-apb-dma.c
> > +++ b/drivers/dma/tegra20-apb-dma.c
> > @@ -1306,6 +1306,8 @@ static int __devinit tegra_dma_probe(struct platform_device *pdev)
> >
> >   	dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
> >   	dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
> > +	dma_cap_set(DMA_CYCLIC, tdma->dma_dev.cap_mask);
> > +
> >   	tdma->dma_dev.dev =&pdev->dev;
> >   	tdma->dma_dev.device_alloc_chan_resources =
> >   					tegra_dma_alloc_chan_resources;
> What sort of testing went into this.

I used the function snd_dmaengine_pcm_open() in 
sound/soc/soc-dmaengine-pcm.c.
This fails because dmaengine_pcm_request_channel() require caps of 
DMA_CYCLIC
which is called by snd_dmaengine_pcm_open().


> I can see that you are marking descriptor complete even for cyclic case,
> that is wrong you should fix that as well. See the other drivers for
> cyclic handling of descriptors.

Not really,
I called dma_cookie_complete() only from the isr handle_once_dma_done() 
which is only called if it is non-cyclic mode.


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