Re: [RFC PATCH 07/11] arm64: dts: qcom: hamoa: Move Iris IOMMUs to sub nodes

[Dmitry Baryshkov]

On Thu, Jul 09, 2026 at 06:05:53PM +0530, Vikash Garodia wrote:
> The Iris VPU has separate streams with different IOVA constraints. The
> non-pixel stream must be limited to the 0-600 MB IOVA range, while the
> pixel stream can use the full IOVA space.
> Using a single set of IOMMU entries for the Iris node does not describe
> these per-stream limits and can allow accesses outside the supported
> range, which may lead to device crashes. One such issue was reported at:
> https://gitlab.freedesktop.org/drm/msm/-/work_items/100
> 
> Add non-pixel and pixel child nodes, move each stream ID to its
> corresponding child node, and add a reserved IOVA range for the
> non-pixel stream.
> 
> Co-developed-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/qcom/hamoa.dtsi | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> index 60f485a4892e062980d01f0b930af4b02f36513c..a2baa2c9f46dc19c3db11dc784358223a035475f 100644
> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> @@ -657,6 +657,10 @@ smem_mem: smem@ffe00000 {
>  			hwlocks = <&tcsr_mutex 3>;
>  			no-map;
>  		};
> +
> +		iris_resv: reservation-iris {
> +			iommu-addresses = <&iris_non_pixel 0x0 0x0 0x0 0x25800000>;
> +		};
>  	};
>  
>  	qup_opp_table_100mhz: opp-table-qup100mhz {
> @@ -5435,10 +5439,11 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
>  			resets = <&gcc GCC_VIDEO_AXI0_CLK_ARES>;
>  			reset-names = "bus";
>  
> -			iommus = <&apps_smmu 0x1940 0>,
> -				 <&apps_smmu 0x1947 0>;
>  			dma-coherent;
>  
> +			#address-cells = <2>;
> +			#size-cells = <2>;
> +
>  			/*
>  			 * IRIS firmware is signed by vendors, only
>  			 * enable on boards where the proper signed firmware
> @@ -5446,6 +5451,15 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
>  			 */
>  			status = "disabled";
>  
> +			iris_non_pixel: non-pixel {
> +				iommus = <&apps_smmu 0x1940 0x0>;
> +				memory-region = <&iris_resv>;
> +			};
> +
> +			iris_pixel: pixel {

Unused label. Also, shouldn't you specify the IOMMU region for this one
too?

> +				iommus = <&apps_smmu 0x1947 0x0>;
> +			};
> +
>  			iris_opp_table: opp-table {
>  				compatible = "operating-points-v2";
>  
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry