Re: [PATCH v4 08/13] arm64: dts: qcom: hamoa: Add Iris context bank subnodes

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing IOMMU configuration for dynamically created dummy platform devices.
--

commit 27813a8c872ca25525366d3507070b27ab569ab8
Author: Vikash Garodia <vikash.garodia@oss.qualcomm.com>

arm64: dts: qcom: hamoa: Add Iris context bank subnodes

This commit adds non-pixel and pixel subnodes to the video-codec node to
assign specific IOVA address ranges to different SMMU streams. It replaces the
single iommus property on the parent node with subnode-specific configurations.

> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> index fcd88e5f5d7ee..63e9ad58097f7 100644
> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi

[ ... ]

> @@ -5473,6 +5475,15 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
>  			 */
>  			status = "disabled";
>  
> +			non-pixel {
> +				iommus = <&apps_smmu 0x1940 0x0>;
> +				iommu-ranges = <0x25800000 0xba800000>;
> +			};
> +
> +			pixel {
> +				iommus = <&apps_smmu 0x1947 0x0>;
> +			};
> +

[Severity: High]
Since these subnodes are dynamically instantiated as platform devices by the
Iris driver using platform_device_register_full(), they do not have matching
drivers and will never enter really_probe().

The platform bus normally sets up IOMMU and DMA during really_probe() by
calling platform_dma_configure() -> of_dma_configure().

Without the driver manually calling of_dma_configure() on these new
sub-devices, will their IOMMU mappings remain unconfigured?

If they are left unconfigured, could the video-codec hardware streams bypass
the SMMU IOVA allocator or fail DMA mappings, resulting in unhandled SMMU
context faults when a video encoding or decoding session is initiated?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260914-vpu_iommu_iova_handling-v4-0-9b9074a73c41@oss.qualcomm.com?part=8