[alsa-devel] ASoC v2 on PowerPC

Timur Tabi timur at freescale.com
Fri Oct 5 16:03:59 CEST 2007

Jon Smirl wrote:
> On 10/5/07, Liam Girdwood <lg at opensource.wolfsonmicro.com> wrote:
>> A good place to start would be looking at the other supported
>> architectures and codecs and see what fits in best with your target SoC
>> CPU. Fwiw, Timur Tabi has some working PPC code, although I'm not sure
>> if it will work on Efika.
> Efika is STAC9766, ac97 with no i2c control. I dug into the imx ac97
> driver and discovered that it isn't finished.

A lot of the i.MX code just sits in BSPs and is never forwarded to the main 

> Timur, we may need to get some Bestcomm tasks written. I haven't
> explored this yet but I've been told that no one can get anything
> except the general DMA task working for audio. This mean all audio
> input has to be 32b. Isn't Bestcomm capable of expanding 16/24 bit
> data? Our target hardware is i2s, not ac97, so I need to get i2s
> running too.

I'm working on an audio driver for the 8610, but I'm going to target ASoC V1 
first, just so that I can get a better feel for how V2 is different (a sort of 
"trial by fire").

I don't know much about Bestcomm, but the DMA engine on the the 8610 is much 
simpler, from what I've heard.  I only work on 83xx, 85xx, and 86xx, so I 
really can't answer any Bestcomm questions.

As for requiring all audio to be 32b, that's not such a bad thing.  Any 
application that uses the standard ALSA interface will have format-conversion 
plug-ins automatically invoked.  The overhead will be minor, since it has to 
do a byte-copy anyway.

Timur Tabi
Linux Kernel Developer @ Freescale

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