Re: [RFC PATCH 0/3] Introduce iommu-map-masked for platform devices

[Dmitry Baryshkov]

On Tue, Oct 14, 2025 at 04:07:37PM +0100, Bryan O'Donoghue wrote:
> On 13/10/2025 13:31, Dmitry Baryshkov wrote:
> > 
> > And from DT perspective compare:
> > 
> > 		fastrpc {
> > 			compatible = "qcom,fastrpc";
> > 			#address-cells = <1>;
> > 			#size-cells = <0>;
> > 
> > 			compute-cb@3 {
> > 				compatible = "qcom,fastrpc-compute-cb";
> > 				reg = <3>;
> > 				iommus = <&apps_smmu 0x1803 0x0>;
> > 			};
> > 
> > 			compute-cb@4 {
> > 				compatible = "qcom,fastrpc-compute-cb";
> > 				reg = <4>;
> > 				iommus = <&apps_smmu 0x1804 0x0>;
> > 			};
> > 
> > 			compute-cb@5 {
> > 				compatible = "qcom,fastrpc-compute-cb";
> > 				reg = <5>;
> > 				iommus = <&apps_smmu 0x1805 0x0>;
> > 			};
> > 		};
> 
> Sorry this is perfect.
> 
> Each function id can be associated with a device and a compat string
> associated with it.

So, which part of the hardware is described by the -cb device? What does
it mean _here_?

> There's no weirdness with iommu-map, you get a struct device for your SID
> and you associate the SID with the FUNCTION_ID you want.
> 
> In fact the FUNCTION_ID could conceivably be the reg. It could be stored in
> platform code.

-- 
With best wishes
Dmitry