Re: [RFC PATCH 01/11] dt-bindings: media: qcom,sm8550-iris: Add vpu sub nodes

[Dmitry Baryshkov]

On Thu, Jul 09, 2026 at 06:05:47PM +0530, Vikash Garodia wrote:
> VPU hardwares have a limitation where VPU streams are associated with
> dedicated addressable address range, as illustrated below
> 
>     +-----------------------------------------------------------+
>     | Stream A reserved region (600 MB)                         |
>     | 0x00000000 - 0x25800000                                   |
>     +-----------------------------------------------------------+
>     | Stream B reserved region (3.5 GB)                         |
>     | 0x00000000 - 0xe0000000                                   |
>     +-----------------------------------------------------------+
>     | Other reserved regions                                    |
>     +-----------------------------------------------------------+
> 
> Mapping a stream outside its expected range can cause unintended
> behavior, including device crashes, as reported at:
> https://gitlab.freedesktop.org/drm/msm/-/work_items/100
> 
> To address this limitation, the subset of stream/s are now represented as
> sub nodes, so that they can be associated to the respective addressable
> range.
> The limitation could be exposed when running usecase like concurrent
> video sessions. The binding have been validated with higher concurrent
> sessions across the SOCs supported under this schema.
> 
> Co-developed-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
> ---
>  .../bindings/media/qcom,sm8550-iris.yaml           | 66 +++++++++++++++++++++-
>  1 file changed, 63 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> index 0400ca1bff05dcef6b742c3fbf77e38adca9f280..bf4d24ce90bd38666704274390b98be450f708c0 100644
> --- a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> @@ -91,6 +91,51 @@ properties:
>    opp-table:
>      type: object
>  
> +  '#address-cells':
> +    const: 2
> +
> +  '#size-cells':
> +    const: 2
> +
> +  non-pixel:
> +    type: object
> +    description:
> +      Non pixel context bank is needed when video hardware have distinct iommus for non pixel
> +      buffers. Non pixel buffers are compressed and internal buffers.
> +    properties:
> +      iommus:
> +        maxItems: 1
> +      memory-region:
> +        maxItems: 1
> +    required:
> +      - iommus
> +      - memory-region
> +    additionalProperties: false
> +
> +  pixel:
> +    type: object
> +    description:
> +      Pixel context bank is needed when video hardware have distinct iommus for pixel buffers.
> +      Pixel buffers are uncompressed buffers.
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +    additionalProperties: false
> +
> +  firmware:
> +    type: object
> +    description:
> +      Firmware context bank represents the firmware processing domain of the VPU. Required to boot
> +      VPU when no hypervisor is present.
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +    additionalProperties: false
> +
>  required:
>    - compatible
>    - power-domain-names
> @@ -98,9 +143,15 @@ required:
>    - interconnect-names
>    - resets
>    - reset-names
> -  - iommus
>    - dma-coherent
>  
> +oneOf:
> +  - required:
> +      - iommus
> +  - required:
> +      - non-pixel
> +      - pixel
> +
>  allOf:
>    - if:
>        properties:
> @@ -177,12 +228,21 @@ examples:
>          resets = <&gcc GCC_VIDEO_AXI0_CLK_ARES>;
>          reset-names = "bus";
>  
> -        iommus = <&apps_smmu 0x1940 0x0000>,
> -                 <&apps_smmu 0x1947 0x0000>;
>          dma-coherent;
>  
>          operating-points-v2 = <&iris_opp_table>;
>  
> +        #address-cells = <2>;
> +        #size-cells = <2>;

I think you need "ranges;" here. Also an empty line before the subnodes.

> +        iris_non_pixel: non-pixel {

Drop useless labels.

> +            iommus = <&apps_smmu 0x1940 0x0000>;
> +            memory-region = <&iris_resv>;
> +        };
> +
> +        iris_pixel: pixel {
> +            iommus = <&apps_smmu 0x1947 0x0000>;
> +        };
> +
>          iris_opp_table: opp-table {
>              compatible = "operating-points-v2";
>  
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry