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

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] dt-bindings: sound: q6apm-dai: schema allows omitting both iommus and memory-region
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commit 0ba7ab9d36bf919ab318abe00f3ad28279a11313
Author: Ajay Kumar Nandam <ajay.nandam@oss.qualcomm.com>

dt-bindings: sound: qcom,q6apm-dai: add memory-region and relax iommus

This commit adds an optional memory-region property for control-path
and data-path carveouts on modem-DSP platforms. It also removes iommus
from the required list because mDSP platforms lack IOMMU or VMID device
tree properties.

> diff --git a/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml b/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml
> index 9e5b30d9c6e62..7d0415f2463a5 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

[Severity: Medium]
Does removing iommus here without adding a constraint like oneOf or anyOf
allow the schema to silently pass if both properties are omitted?

If a device tree is written without either iommus or memory-region, it looks
like it will incorrectly pass schema validation. At runtime, the driver would
then allocate normal memory, and when the DSP attempts to access it, it could
trigger an SMMU or stage-2 translation fault and crash the DSP/subsystem.

Should we add a structural constraint to enforce that at least one of the
memory protection mechanisms is specified?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260922-vmid-v4-v5-0-e79cfd7af5b3@oss.qualcomm.com?part=3