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

[Ajay Kumar Nandam <ajay.nandam@oss.qualcomm.com>]

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