Re: [PATCH RFC v2 04/14] arm64: dts: qcom: sm8650: move smmu sid 1 to new lpac device

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 10/29/26 2:52 PM, Anna Maniscalco wrote:
> Previously both SID 0 and 1 where associated with the same domain.
> 
> When LPAC is not used this is needed so firmware can acces memory when
> initializing using the same page table as GFX.
> 
> To use LPAC however we need to move SID 1 to a different device.
> 
> Signed-off-by: Anna Maniscalco <anna.maniscalco2000@gmail.com>
> ---
>  arch/arm64/boot/dts/qcom/sm8650.dtsi | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sm8650.dtsi b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> index 1604bc8cff37..f47d1dbd06da 100644
> --- a/arch/arm64/boot/dts/qcom/sm8650.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> @@ -4144,8 +4144,7 @@ gpu: gpu@3d00000 {
>  
>  			interrupts = <GIC_SPI 300 IRQ_TYPE_LEVEL_HIGH 0>;
>  
> -			iommus = <&adreno_smmu 0 0x0>,
> -				 <&adreno_smmu 1 0x0>;
> +			iommus = <&adreno_smmu 0 0x0>;
>  
>  			operating-points-v2 = <&gpu_opp_table>;
>  
> @@ -4158,6 +4157,12 @@ gpu: gpu@3d00000 {
>  
>  			status = "disabled";
>  
> +			lpac: lpac {
> +				compatible = "qcom,lpac";

I'm debating what to do with the compatible here.. On one hand they
shouldn't be generic (should be soc hw specific instead, but that
feels a little overkill here) and it may be that we even don't need
one, but the iommu driver needs to know what we need a 1:1 mapping
hmm..

Konrad

> +
> +				iommus = <&adreno_smmu 1 0x0>;
> +			};
> +
>  			gpu_zap_shader: zap-shader {
>  				memory-region = <&gpu_micro_code_mem>;
>  			};
>