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

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Message-ID: <10a8ccda-4e27-4b06-9a0e-608d6ade5354@nxsw.ie>
Date: Tue, 7 Oct 2025 15:29:14 +0100
From: Bryan O'Donoghue <bod.linux@...w.ie>
To: Bryan O'Donoghue <bod@...nel.org>,
 Charan Teja Kalla <charan.kalla@....qualcomm.com>,
 Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
 Bryan O'Donoghue <bryan.odonoghue@...aro.org>
Cc: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
 Krzysztof Kozlowski <krzk@...nel.org>,
 Vikash Garodia <quic_vgarodia@...cinc.com>,
 Dikshita Agarwal <quic_dikshita@...cinc.com>,
 Abhinav Kumar <abhinav.kumar@...ux.dev>,
 Mauro Carvalho Chehab <mchehab@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, linux-media@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/5] Introduce "non-pixel" sub node within iris video
 node

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@...l.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