Re: [PATCH v5 01/13] dt-bindings: media: qcom,venus: Add context bank subnodes to common schema

[Zhangfei Gao]

On Sat, Sep 26, 2026 at 2:38 PM Vikash Garodia
<vikash.garodia@xxxxxxxxxxxxxxxx> wrote:
>
> The VPU issues DMA through several SMMU streams, and the hardware does
> not give every stream the same addressable range. The non-pixel stream
> cannot address the low 600MB of IOVA space, while the pixel stream can
> address the full range:
>     +-----------------------------------------------------------+
>     | non-pixel stream addressable range (600 MB - 3.5 GB)      |
>     | 0x25800000 - 0xe0000000                                   |
>     +-----------------------------------------------------------+
>     | pixel stream addressable range (0 - 3.5 GB)               |
>     | 0x00000000 - 0xe0000000                                   |
>     +-----------------------------------------------------------+
> A single "iommus" property on the video-codec node puts every stream in
> one IOMMU domain sharing one IOVA allocator, so nothing restricts a
> non-pixel buffer to avoid 0 to 600MB. Once an allocation lands below
> that boundary the hardware faults, which shows up as unhandled SMMU page
> faults and spontaneous reboots:
> https://gitlab.freedesktop.org/drm/msm/-/work_items/100
>
> Given that the address range restriction is for specific VPU stream, it
> should be ideally be moved to that stream. To achieve the same, a subset
> of streams is now represented as subnodes, so that each can be
> associated with its respective addressable range. The design was
> discussed and agreed by mainatiners here
> https://lore.kernel.org/all/c7b956a9-d3e8-4e18-b780-5d08f5cd2ca1@xxxxxxxxxx
>
> In the past, this limitation was addressed with an iommu-map approach,
> with the iris driver dynamically creating the devices. That approach was
> later concluded to be a hack to avoid having subnodes, and was NAKed by
> the iommu maintainers. It was discussed in detail here:
> https://lore.kernel.org/all/c7b956a9-d3e8-4e18-b780-5d08f5cd2ca1@xxxxxxxxxx/
>
> "iommu-ranges" on the subnode describes the *allowed* IOVA range that
> stream is allowed to use, so the IOVA is allocated from the specified
> range only. Define all the possible subnodes so as to describe all the
> VPU hardware iommu interfaces, both secure as well as non secure.
>
> address-cells, size-cells and dma-ranges declares the 1:1 DMA
> translation into the parent.
>
> The parent "iommus" is kept as an alternative via "oneOf", so platforms
> that have not been converted to subnodes still validate. New platforms
> should use the subnode form.
>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
> ---
>  .../bindings/media/qcom,sc7180-venus.yaml          | 15 ----
>  .../bindings/media/qcom,venus-common.yaml          | 97 ++++++++++++++++++++++
>  2 files changed, 97 insertions(+), 15 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml b/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
> index b21bed314848480b82153e49602f0b19e08e7335..bfd8b1ad473128c974bce84639cb0aff59d8c2cc 100644
> --- a/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
> @@ -91,21 +91,6 @@ properties:
>      deprecated: true
>      additionalProperties: false
>
> -  video-firmware:
> -    type: object
> -    additionalProperties: false
> -
> -    description: |
> -      Firmware subnode is needed when the platform does not
> -      have TrustZone.
> -
> -    properties:
> -      iommus:
> -        maxItems: 1
> -
> -    required:
> -      - iommus
> -
>  required:
>    - compatible
>    - power-domain-names
> diff --git a/Documentation/devicetree/bindings/media/qcom,venus-common.yaml b/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> index 59a3fde846d2196ab1e4588eb396012ba6860712..68d5e592a028c5eecde04ce72cd5ae6815ba5c82 100644
> --- a/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
> @@ -47,6 +47,93 @@ properties:
>      minItems: 1
>      maxItems: 4
>
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 1
> +
> +  dma-ranges:
> +    maxItems: 1
> +
> +  non-pixel:
> +    type: object
> +    description:
> +      Context bank for VPU non-pixel buffers, including compressed and internal buffers.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +      iommu-ranges:
> +        maxItems: 1
> +    required:
> +      - iommus
> +      - iommu-ranges
> +
> +  pixel:
> +    type: object
> +    description:
> +      Context bank for VPU pixel buffers containing uncompressed video data.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +
> +  video-firmware:
> +    type: object
> +    description:
> +      Context bank for the VPU firmware processing domain.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +
> +  secure-non-pixel:
> +    type: object
> +    description:
> +      Context bank for VPU secure non-pixel buffers.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +      iommu-ranges:
> +        maxItems: 1
> +    required:
> +      - iommus
> +      - iommu-ranges
> +
> +  secure-pixel:
> +    type: object
> +    description:
> +      Context bank for VPU secure pixel buffers containing uncompressed video data.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +
> +  secure-bitstream:
> +    type: object
> +    description:
> +      Context bank for VPU secure bitstream buffers containing compressed video data.
> +    additionalProperties: false
> +
> +    properties:
> +      iommus:
> +        maxItems: 1
> +    required:
> +      - iommus
> +
>  required:
>    - reg
>    - clocks
> @@ -55,4 +142,14 @@ required:
>    - memory-region
>    - power-domains
>
> +oneOf:
> +  - required:
> +      - iommus
> +  - required:
> +      - '#address-cells'
> +      - '#size-cells'
> +      - dma-ranges
> +      - non-pixel
> +      - pixel
> +
>  additionalProperties: true
>
Got this warning:
arch/arm64/boot/dts/qcom/nord-rrd.dtb: non-pixel: iommu-ranges:
b'%\x80\x00\x00\xda`\x00\x00' is not of type 'object', 'integer',
'array', 'boolean', 'null'
arch/arm64/boot/dts/qcom/nord-ride-embedded.dtb: non-pixel:
iommu-ranges: b'%\x80\x00\x00\xda`\x00\x00' is not of type 'object',
'integer', 'array', 'boolean', 'null'

Need
--- a/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
+++ b/Documentation/devicetree/bindings/media/qcom,venus-common.yaml
@@ -67,7 +67,9 @@ properties:
         minItems: 1
         maxItems: 3
       iommu-ranges:
-        maxItems: 1
+        $ref: /schemas/types.yaml#/definitions/uint32-array
+        minItems: 2
+        maxItems: 2
     required:
       - iommus
       - iommu-ranges
@@ -106,7 +108,9 @@ properties:
       iommus:
         maxItems: 1
       iommu-ranges:
-        maxItems: 1
+        $ref: /schemas/types.yaml#/definitions/uint32-array
+        minItems: 2
+        maxItems: 2
     required:
       - iommus
       - iommu-ranges

Thanks