Re: [PATCH v35 00/31] Introduce QC USB SND audio offloading support

[Wesley Cheng]

Hi Stephan,

On 3/4/2025 12:22 AM, Stephan Gerhold wrote:
> On Mon, Mar 03, 2025 at 06:39:52PM -0800, Wesley Cheng wrote:
>>
>>
>> On 2/19/2025 3:24 AM, Stephan Gerhold wrote:
>>> On Tue, Feb 18, 2025 at 04:47:23PM -0800, Wesley Cheng wrote:
>>>> Requesting to see if we can get some Acked-By tags, and merge on usb-next.
>>>>
>>>> Several Qualcomm based chipsets can support USB audio offloading to a
>>>> dedicated audio DSP, which can take over issuing transfers to the USB
>>>> host controller.  The intention is to reduce the load on the main
>>>> processors in the SoC, and allow them to be placed into lower power modes.
>>>> There are several parts to this design:
>>>>   1. Adding ASoC binding layer
>>>>   2. Create a USB backend for Q6DSP
>>>>   3. Introduce XHCI interrupter support
>>>>   4. Create vendor ops for the USB SND driver
>>>>
>>>>       USB                          |            ASoC
>>>> --------------------------------------------------------------------
>>>>                                    |  _________________________
>>>>                                    | |sm8250 platform card     |
>>>>                                    | |_________________________|
>>>>                                    |         |           |
>>>>                                    |      ___V____   ____V____
>>>>                                    |     |Q6USB   | |Q6AFE    |
>>>> |     |"codec" | |"cpu"    |
>>>>                                    |     |________| |_________|
>>>>                                    |         ^  ^        ^
>>>>                                    |         |  |________|
>>>>                                    |      ___V____    |
>>>>                                    |     |SOC-USB |   |
>>>>    ________       ________               |        |   |
>>>>   |USB SND |<--->|QC offld|<------------>|________|   |
>>>>   |(card.c)|     |        |<----------                |
>>>>   |________|     |________|___     | |                |
>>>>       ^               ^       |    | |    ____________V_________
>>>>       |               |       |    | |   |APR/GLINK             |
>>>>    __ V_______________V_____  |    | |   |______________________|
>>>>   |USB SND (endpoint.c)     | |    | |              ^
>>>>   |_________________________| |    | |              |
>>>>               ^               |    | |   ___________V___________
>>>>               |               |    | |->|audio DSP              |
>>>>    ___________V_____________  |    |    |_______________________|
>>>>   |XHCI HCD                 |<-    |
>>>>   |_________________________|      |
>>>>
>>>
>>> As I noted on v34 [1], this version is still missing instructions and
>>> changes needed for testing this series. The device tree changes don't
>>> need to be part of the same series, but there should be at least a link
>>> provided to give other people the chance to provide Tested-by tags.
>>>
>>> IMO we shouldn't merge this series without those instructions, otherwise
>>> we risk that this just ends up being dead code that no one can use.
>>>
>>> Can you please share the device tree changes for a board upstream and
>>> any other changes needed to be able to test this series? E.g. for
>>> sm8250-mtp.dts, based on the examples in your cover letter.
>>>
>>
>> To clarify I'm testing this on sm8350 in recent times, but utilizing sm8250
>> definitions for the ASoC platform card, as the platform sound card is more
>> or less the same between the two SoCs.  Back
>> when I started this series, sm8350 was missing a bunch of dependent
>> components, such as aDSP not being loaded, and missing platform sound card
>> definition, so I had to define and enable those on my own, which required a
>> slew of new DT nodes, hence why it wasn't as straight forward to include
>> the DT definitions yet for sm8350.  Not thinking that this series would
>> take as long as it did, I was planning on separating out the DT changes in
>> a different series to enable offloading for the devices I have tested with.
>> (sm8150, sm8250 and sm8350)
>>
>> There's still a pretty big chunk of dependencies missing from sm8350, so
>> those would also be handled in the follow up DT submission.  For now, its a
>> much bigger hurdle to get the main/functional changes in, and that was
>> taking a significant amount of time from my end to manage.
>>
>> If you want, I can give you the changes I have offline to enable this for
>> sm8350, since I haven't spent time formatting/prepping the changes for
>> submission yet.
>>
> 
> Can you push it to a public branch somewhere (e.g. on CodeLinaro)? I was
> talking to some people from the community about testing this on some of
> the smartphones we have in upstream, so it wouldn't help if I just have
> the changes privately.

Which CLO project/branch did you want me to push it to?  Sorry, I haven't
worked too much with the CLO open branches.  I have an account though.

Thanks
Wesley Cheng