Re: [alsa-devel] soc-dsp programming model for loopbacks
On Tue, Jan 24, 2012 at 01:36:18PM -0800, Pierre-Louis Bossart wrote:
Now if the FM radio routing is handled with a digital loopback on the application processor audio dsp (omap-abe, Intel SST, etc), then soc-dsp will need to be used. And for a simple FM playback, I need to
Note that the use of soc-dsp isn't required for on-SoC DSPs - it really depends on how the hardware looks. If the DSP external format is very strongly tied to the format used to DMA to and from main memory (or other interfaces) then soc-dsp is what you need, if the DSP is able to rewrite formats more flexibly then it should be more direct to model it as a CODEC device with whatever number of DAIs and routing between them.
On Tue, 2012-01-24 at 22:00 +0000, Mark Brown wrote:
On Tue, Jan 24, 2012 at 01:36:18PM -0800, Pierre-Louis Bossart wrote:
Now if the FM radio routing is handled with a digital loopback on the application processor audio dsp (omap-abe, Intel SST, etc), then soc-dsp will need to be used. And for a simple FM playback, I need to
Note that the use of soc-dsp isn't required for on-SoC DSPs - it really depends on how the hardware looks. If the DSP external format is very strongly tied to the format used to DMA to and from main memory (or other interfaces) then soc-dsp is what you need, if the DSP is able to rewrite formats more flexibly then it should be more direct to model it as a CODEC device with whatever number of DAIs and routing between them.
It's also needed if your DSP cant control or configure any of your host CPU DAI hardware controllers that it needs to physically use to route audio data.
Regards
Liam
On Wed, Jan 25, 2012 at 05:12:25PM +0000, Liam Girdwood wrote:
On Tue, 2012-01-24 at 22:00 +0000, Mark Brown wrote:
Note that the use of soc-dsp isn't required for on-SoC DSPs - it really depends on how the hardware looks. If the DSP external format is very strongly tied to the format used to DMA to and from main memory (or other interfaces) then soc-dsp is what you need, if the DSP is able to rewrite formats more flexibly then it should be more direct to model it as a CODEC device with whatever number of DAIs and routing between them.
It's also needed if your DSP cant control or configure any of your host CPU DAI hardware controllers that it needs to physically use to route audio data.
Depends how they're allocated - the DSP driver can always do the management on behalf of the DSP firmware if the hardware is structured in a way that makes that make sense (for example, if the CPU never talks to the outside world directly).
On Wed, 2012-01-25 at 17:20 +0000, Mark Brown wrote:
On Wed, Jan 25, 2012 at 05:12:25PM +0000, Liam Girdwood wrote:
On Tue, 2012-01-24 at 22:00 +0000, Mark Brown wrote:
Note that the use of soc-dsp isn't required for on-SoC DSPs - it really depends on how the hardware looks. If the DSP external format is very strongly tied to the format used to DMA to and from main memory (or other interfaces) then soc-dsp is what you need, if the DSP is able to rewrite formats more flexibly then it should be more direct to model it as a CODEC device with whatever number of DAIs and routing between them.
It's also needed if your DSP cant control or configure any of your host CPU DAI hardware controllers that it needs to physically use to route audio data.
Depends how they're allocated - the DSP driver can always do the management on behalf of the DSP firmware if the hardware is structured in a way that makes that make sense (for example, if the CPU never talks to the outside world directly).
Wouldn't that either mean the DSP driver (re)implements some of the CPU DAI driver operations OR the DSP driver calling the CPU DAI driver ops directly ?
Regards
Liam
On Wed, Jan 25, 2012 at 05:48:57PM +0000, Liam Girdwood wrote:
On Wed, 2012-01-25 at 17:20 +0000, Mark Brown wrote:
Depends how they're allocated - the DSP driver can always do the management on behalf of the DSP firmware if the hardware is structured in a way that makes that make sense (for example, if the CPU never talks to the outside world directly).
Wouldn't that either mean the DSP driver (re)implements some of the CPU DAI driver operations OR the DSP driver calling the CPU DAI driver ops directly ?
Like I say it depends on how the hardware is structured - the cases I was thinking about in the example above were those where the CPU needs to push everything through the DSP (or other in-SoC IP block, some have other interesting hardware in the way) so the DAI driver the CPU itself ends up with is different to and probably much simpler than that for the external interface.
participants (2)
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Liam Girdwood -
Mark Brown