[alsa-devel] [RFC 4/7] ASoC: Add dmaengine PCM helper functions

Vinod Koul vinod.koul at linux.intel.com
Wed Feb 22 14:30:09 CET 2012

On Wed, 2012-02-22 at 13:21 +0000, Mark Brown wrote:
> On Wed, Feb 22, 2012 at 10:49:08AM +0100, Lars-Peter Clausen wrote:
> > This patch adds a set of functions which are intended to be used when
> > implementing a dmaengine based sound PCM driver.
> Looks good - if you need to resend then:
> > + * Note that this function will use private_data field of the substream's
> > + * runtime. So it is not availabe to your pcm driver implementation. If you need
> > + * to keep additional data attached to a substream use
> > + * snd_dmaeinge_pcm_{set,get}_data.
> there's a typo here but no need to resend just for that.
> I'd like to see some review from both Morimoto-san as we should convert
> fsi over to this too, Vinod I guess you're also pretty much happy given
> your comments on the previous version?
Acked-by :Vinod Koul <vinod.koul at linux.intel.com>
> For the non-cyclic DMAs the idea of emulating at the dmaengine layer
> does seem very sensible but if that's hard then having the code at the
> ASoC level and pushing it down later seems fine.  We do have several
> platforms with non-cyclic DMA so it's a general need.
I think this should be pushed to dmaengine rather than in ASoC. That way
ASoC can always request circular and we emulate the behavior in
dmaengine for dmacs who don't support this


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