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

Krzysztof Kozlowski
2025-10-09T00:47:11Z

On 09/10/2025 09:43, Bryan O'Donoghue wrote:
> On 09/10/2025 01:32, Krzysztof Kozlowski wrote:
>>>> Since it is the smmu device property , this suggestion expects all the
>>>> devices, not just video, to define additional argument. Does this look
>>>> valid?
>>> If it is legitimate meta-data for the SMMU setup then why_shouldn't_ it
>>> go into the DT ?
>>>
>> We talked about this two or three months ago. I don't understand why you
>> just ignored that entire part and come with new binding just to not
>> touch iommu code. List of entries in iommu must have strict order, just
>> like for every other list, and you should rely on that.
>
> I don't know if you mean me here.

I meant Qualcomm. Anyway this was already proposed and received the same
feedback from Rob, so you are a bit duplicating the discussion here.

>
> Just to clarify my point is; the FUNCTION_ID is just as legitimate as
> the SID to specify in the DT.
>
> It shouldn't be in driver platform data. It perfectly valid to add
> another field to the iommu and then modify the iommu code to parse that
> additional field we have added.
>
> There has been some suggestion of an inferred index, I'm not sure how
> that could really work.
>
> The right thing to do is:
>
> - Add FUNCTION_ID to the iommu entries
> - Modify the iommu code to consume that data.
>
> Maybe it would be possible to also use an inferred FUNCTION_ID somehow
> though TBH I think that's a work-around.

Three months ago I gave you the answer for that - it is inferred by
index on the list.

Best regards,
Krzysztof