Re: [PATCH v4 1/3] dt-bindings: media: qcom,qcm2290-venus: document shikra Iris compatible

[Krzysztof Kozlowski <krzk@kernel.org>]

On Tue, Jul 21, 2026 at 11:02:25PM +0530, Vikash Garodia wrote:
> Document the iris video accelerator used on shikra platforms by adding
> the qcom,shikra-iris compatible.

iris here, venus in the compatible. Please decide which one.

> 
> Although QCM2290 and shikra share the same video hardware and overall
> integration, their SMMU programming differs. QCM2290 exposes separate
> stream IDs for the video hardware and the Xtensa path, requiring two
> explicit IOMMU entries, whereas shikra uses a masked SMR to collapse
> equivalent stream IDs into a single mapping. Due to QCM2290’s SID layout
> and Xtensa isolation requirements, such SMR masking is not applicable on
> QCM2290 platforms.

This paragraph suggests devices are not compatible. Will Shikra Iris
work fine when driver matches with qcom,qcm2290-venus?

> Since shikra uses the same video hardware as QCM2290 and shares the same
> programming model and capabilities, it is added as a fallback compatible
> to qcom,qcm2290-venus, with conditional handling to allow either one or
> two IOMMU entries.
> Common schema is updated to accommodate the iova restriction of 600MB.
> VPU restricts usage of 600MB for specific streams, which could otherwise
> lead to device crash.
> 
> Reviewed-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
> Signed-off-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> ---
>  .../bindings/media/qcom,qcm2290-venus.yaml         | 26 ++++++++++++++++------
>  .../bindings/media/qcom,venus-common.yaml          |  5 ++++-
>  2 files changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/qcom,qcm2290-venus.yaml b/Documentation/devicetree/bindings/media/qcom,qcm2290-venus.yaml
> index 5977e7d0a71b4fb5681f1c2094439c251366f01f..b27899ebf164229ceff1ca5cda50ee30d875e953 100644
> --- a/Documentation/devicetree/bindings/media/qcom,qcm2290-venus.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,qcm2290-venus.yaml
> @@ -13,14 +13,13 @@ description:
>    The Venus AR50_LITE IP is a video encode and decode accelerator present
>    on Qualcomm platforms.
>  
> -allOf:
> -  - $ref: qcom,venus-common.yaml#
> -
>  properties:
>    compatible:
>      oneOf:
>        - items:
> -          - const: qcom,sm6115-venus
> +          - enum:
> +              - qcom,shikra-venus
> +              - qcom,sm6115-venus
>            - const: qcom,qcm2290-venus
>        - const: qcom,qcm2290-venus
>  
> @@ -45,9 +44,6 @@ properties:
>        - const: vcodec0_core
>        - const: vcodec0_bus
>  
> -  iommus:
> -    maxItems: 2
> -
>    interconnects:
>      maxItems: 2
>  
> @@ -65,6 +61,22 @@ required:
>    - power-domain-names
>    - iommus
>  
> +allOf:
> +  - $ref: qcom,venus-common.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: qcom,shikra-venus
> +    then:
> +      properties:
> +        iommus:
> +          maxItems: 1
> +    else:
> +      properties:
> +        iommus:
> +          maxItems: 2
> +
>  unevaluatedProperties: false
>  
>  examples:
> diff --git a/Documentation/devicetree/bindings/media/qcom,venus-common.yaml b/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> index 59a3fde846d2196ab1e4588eb396012ba6860712..0be2f9119e78233928d23af86836ac294aa769ee 100644
> --- a/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> @@ -37,7 +37,10 @@ properties:
>      maxItems: 20
>  
>    memory-region:
> -    maxItems: 1
> +    minItems: 1
> +    items:
> +      - description: Firmware-loaded codec carveout
> +      - description: IOMMU IOVA reservation region

This adds second region to several other devices using
qcom,venus-common.yaml, thus should be its own commit with its own
rationale why all devices take the IOMMU IOVA region now.

>  
>    power-domains:
>      minItems: 1
> 
> -- 
> 2.34.1
>