Re: [PATCH 1/2] dt-bindings: media: qcom,sm8550-iris: Allow IOVA reservation memory-region

[Frank Li <Frank.li@nxp.com>]

On Mon, Jun 01, 2026 at 12:13:33PM +0800, Daniel J Blueman wrote:
> In addition to the firmware-loaded codec carveout, some Iris platforms
> need to declare an IOMMU IOVA reservation (a reserved-memory node with
> iommu-addresses) to keep DMA away from IOVA ranges that earlier
> firmware stages have already mapped through the SMMU.
>
> Permit a second memory-region phandle for this purpose, and describe
> the meaning of each entry so the ordering is unambiguous.
>
> Signed-off-by: Daniel J Blueman <daniel@quora.org>
> ---
>  Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> index 9c4b760508b5..6359e4953d42 100644
> --- a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> @@ -80,7 +80,11 @@ properties:
>    dma-coherent: true
>
>    memory-region:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 2
> +    items:
> +      - description: Firmware-loaded codec carveout
> +      - description: IOMMU IOVA reservation region

Suppose you want to special iova space. does dma-ranges work for it?

bus {
     dma-ranges = <start size>;
     iris {
	...
     }
}

Frank
>
>    operating-points-v2: true
>
> --
> 2.53.0
>