linux-kernel - Re: [PATCH 4/9] dt-bindings: arm: qcom,coresight-static-replicator: add optional clocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <3ibbttdnygwsikfm2anusyrg6zoghhlj5sfom2f4ujc434dg22@xa6x5igbrbmf>
Date: Tue, 18 Mar 2025 23:44:23 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Suzuki K Poulose <suzuki.poulose@....com>
Cc: Mike Leach <mike.leach@...aro.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>, Lee Jones <lee@...nel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        James Clark <james.clark@...aro.org>, Leo Yan <leo.yan@...ux.dev>,
        Kumar Gala <galak@...eaurora.org>, Andy Gross <agross@...eaurora.org>,
        "Ivan T. Ivanov" <ivan.ivanov@...aro.org>,
        Andy Gross <andy.gross@...aro.org>, Georgi Djakov <djakov@...nel.org>,
        David Heidelberg <david@...t.cz>, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 4/9] dt-bindings: arm: qcom,coresight-static-replicator:
 add optional clocks

On Tue, Mar 18, 2025 at 01:37:23PM +0000, Suzuki K Poulose wrote:
> On 18/03/2025 12:19, Dmitry Baryshkov wrote:
> > On Tue, Mar 18, 2025 at 10:38:17AM +0000, Suzuki K Poulose wrote:
> > > On 17/03/2025 17:44, Dmitry Baryshkov wrote:
> > > 
> > > nit: Subject:
> > > 
> > > s/qcom,coresight-static-replicator/arm,coresight-static-replicator
> > > 
> > > > As most other CoreSight devices the replicator can use either of the
> > > > optional clocks (or both). Document those optional clocks in the schema.
> > > > 
> > > > Fixes: 3c15fddf3121 ("dt-bindings: arm: Convert CoreSight bindings to DT schema")
> > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> > > > ---
> > > >    .../bindings/arm/arm,coresight-static-replicator.yaml          | 10 ++++++++++
> > > >    1 file changed, 10 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
> > > > index a6f793ea03b6c193fc0ff72a45e0249a63a2ba3c..56e64067ed3d63c5e293a0840858f13428bacb45 100644
> > > > --- a/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
> > > > +++ b/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
> > > > @@ -30,6 +30,16 @@ properties:
> > > >      power-domains:
> > > >        maxItems: 1
> > > > +  clocks:
> > > > +    minItems: 1
> > > > +    maxItems: 2
> > > > +
> > > 
> > > For the static replicator, you don't have an APB clock, as they can't be
> > > programmed. It may have an ATB clock. So minItems 0, maxItems: 1
> > 
> > It can, see qcom-apq8064.dtsi
> > 
> > Also minItems:0 doesn't make sense to me. I'd rather keep this as an
> > optional property rather than requiring an empty set.
> 
> Interesting, that must be atclk in fact. Because a static replicator
> only manages ATB transactions. It doesn't have an APB interface.

Ack. Unfortunately there are platforms (and grepping revealed more than
just APQ8064) that list the apb_pclk. We have to support those DTs :-(

> 
> I am not an expert in DTB schema. But the point is the clocks are optional.

This is handled by not listing the 'clocks' / 'clock-names' under the
'required' list.

> 
> Suzuki
> 
> 
> > 
> > > 
> > > Suzuki
> > > 
> > > 
> > > 
> > > > +  clock-names:
> > > > +    minItems: 1
> > > > +    enum:
> > > > +      - apb_pclk
> > > > +      - atclk
> > > > +
> > > >      in-ports:
> > > >        $ref: /schemas/graph.yaml#/properties/ports
> > > >        additionalProperties: false
> > > > 
> > > 
> > 
> 

-- 
With best wishes
Dmitry