Re: [PATCH v5 3/4] dt-bindings: sound: qcom,q6apm-dai: add memory-region and relax iommus

[Ajay Kumar Nandam]

On 9/23/2026 5:27 PM, Krzysztof Kozlowski wrote:
> > diff --git a/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml b/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml
> > index 9e5b30d9c6e6..7d0415f2463a 100644
> > --- a/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml
> > +++ b/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml
> > @@ -20,9 +20,19 @@ properties:
> >       minItems: 1
> >       maxItems: 2
> >   
> > +  memory-region:
> > +    minItems: 1
> > +    maxItems: 2
> > +    items:
> > +      - description:
> > +          Control-path buffer (audio_heap_mem) for platforms where the DSP
> > +          runs in a stage-2 protected context (e.g. modem-DSP).
> > +      - description:
> > +          Data-path buffer pool from which per-stream DMA buffers are
> > +          allocated.
> > +
> >   required:
> >     - compatible
> > -  - iommus
> I imagine you either have iommus or memory-region, no? IOW,
> oneOf:
>    - required:
>        - iommus
>    - required:
>        - memory-region
> ?

Yes, that matches the intended split.

For existing ADSP/SMMU platforms, q6apm-dais uses iommus. For the 
mDSP/VMID path, the DSP cannot access normal SMMU-backed system 
memory,so the buffers have to come from reserved-memory carveouts which 
the driver SCM-assigns to the fixed VMIDs.

I will add the oneOf constraint in v6 to require either iommus or 
memory-region. VMIDs remain internal to the driver and are not described
in DT.

Thanks
Ajay Kumar Nandam


> Best regards,
> Krzysztof