[alsa-devel] WRITING AN SOC DRIVER WITHOUT DMA

Jon Smirl jonsmirl at gmail.com
Thu Jul 17 22:05:49 EST 2008


On 7/17/08, Nobin Mathew <nobin.mathew at gmail.com> wrote:
> Hi Dinesh,
>
> If that is your requirement then go and see the actual code
> sound/arm/aaci.c. They are not using DMA. It is programmed IO.


Search around the list archives, the first version of the
Efika/mpc5200 ac97 driver was programmed IO. The next version updated
it to DMA.


>
>
> Thanks
> Nobin Mathew
>
>
> On 7/17/08, Mark Brown
> <broonie at opensource.wolfsonmicro.com> wrote:
> > On Thu, Jul 17, 2008 at 11:33:31AM +0530, dinesh wrote:
> >
> > > What i want is that i have a buffer in driver code which is also handled
> > > by some other application i want that this buffer data is to be used for
> > > capture and playback  stream fills data to another buffer which i can
> > > passover to my other application.
> >
> > Depending on what exactly you're doing here you may find that this is
> > best implemented in user space with an ALSA plugin rather than doing it
> > as part of a driver.  If you do want to do this in kernel space then the
> > parts of an ASoC driver which transfer audio data are just the same as
> > those for any other ALSA driver so things like sound/arm/aaci.c may
> > provide useful examples.
> >
>
>
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-- 
Jon Smirl
jonsmirl at gmail.com



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