linux-kernel - Re: [PATCH v7 2/3] arm64: dts: qcom: qcs615: add venus node to devicetree

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Message-ID: <d6udpwmocodvlsm5ljqz7zbyonj2yahtlzmm2jjjveqrm2hmkz@andh5j4jgixr>
Date: Tue, 3 Jun 2025 16:21:54 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Renjiang Han <quic_renjiang@...cinc.com>
Cc: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Vikash Garodia <quic_vgarodia@...cinc.com>,
        Dikshita Agarwal <quic_dikshita@...cinc.com>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...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, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v7 2/3] arm64: dts: qcom: qcs615: add venus node to
 devicetree

On Thu, May 29, 2025 at 10:29:46AM +0800, Renjiang Han wrote:
> 
> On 5/28/2025 7:04 PM, Dmitry Baryshkov wrote:
> > On Wed, May 28, 2025 at 05:13:06PM +0800, Renjiang Han wrote:
> > > On 5/27/2025 9:57 PM, Konrad Dybcio wrote:
> > > > On 5/27/25 5:32 AM, Renjiang Han wrote:
> > > > > Add the venus node to the devicetree for the qcs615 platform to enable
> > > > > video functionality. The qcs615 platform currently lacks video
> > > > > functionality due to the absence of the venus node. Fallback to sc7180 due
> > > > > to the same video core.
> > > > > 
> > > > > Signed-off-by: Renjiang Han <quic_renjiang@...cinc.com>
> > > > > ---
> > > > [...]
> > > > 
> > > > > +			interconnect-names = "video-mem",
> > > > > +					     "cpu-cfg";
> > > > > +
> > > > > +			iommus = <&apps_smmu 0xe40 0x20>;
> > > > fwiw docs mention 0xe60 0x20 (which result in the exact same resulting sid)
> > > OK. Will update it with next version.
> > How would you update this?
> Thanks for your comments. I'll update it like this.
> iommus = <&apps_smmu 0xe60 0x20>;
> 
> This 0xe40 SID was based on a previous project. However, after rechecking
> the documentation yesterday and confirming with colleagues, the correct
> SID value should be 0xe60. I’ve also validated it on local device, it
> works as expected. The reason 0xe40 seemed to work earlier is due to the
> mask value being 0x20, which causes the effective SID derived from 0xe40
> to be the same as 0xe60.

Using 0xe60 would be counterintuitive, as we have a non-zero masked bits
in the base value. It should be either <0xe60 0x0> or <0xe40 0x20>.

-- 
With best wishes
Dmitry