Re: [PATCH v3 0/5] Introduce "non-pixel" sub node within iris video node

Bryan O'Donoghue
2025-10-07T14:44:42Z

On 07/10/2025 15:29, Bryan O'Donoghue wrote:
> On 07/10/2025 15:25, Bryan O'Donoghue wrote:
>> Rob suggested using an implicit index for function id
>>
>> https://lore.kernel.org/all/CAL_JsqK9waZK=i+ov0jV-
>> PonWSfddwHvE94Q+pks4zAEtKc+yg@mail.gmail.com/
>>
>> Couldn't we list the entire set of iommus - then detach - subsequently
>> re-attaching in our platform code with FUNCTION_IDs we keep listed in
>> our drivers ?
>>
>> That way the DT is complete and correct, we have a compliant upstream DT
>> but we also find a way to make the FUNCTION_ID specific setup we need.
>
> i.e. you can keep the FUNCTION_ID "metadata" in the driver and associate
> specific iommu indexes with the FUNCTION_ID you want in there.
>
> That way you could have multiple FUNCTION_ID smmu entries in the DT and
> just associate the DT indexes locally in drivers/platform/qcom/
> iris_metadata_goes_here.c
>
> ---
> bod

Actually why can't we specify FUNCTION_ID in the iommus = <entries>

Surely we could do

#iommu-cells = <4>;
iommus = <&apps_smmu 0x420 0x2 FUNCTION_ID>;

and encode the real data we need directly in the iommus list...

---
bod