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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Wed, 2 Jun 2021 17:26:29 -0700
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Subject: Re: [PATCH v8 3/5] arm64: dts: qcom: sc7180: Enable SoC sleep stats
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Maulik Shah <mkshah@codeaurora.org>, evgreen@chromium.org,
        mka@chromium.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, agross@kernel.org,
        dianders@chromium.org, linux@roeck-us.net, rnayak@codeaurora.org,
        lsrao@codeaurora.org, devicetree@vger.kernel.org
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Quoting Bjorn Andersson (2021-05-31 10:57:03)
> On Wed 26 May 18:30 CDT 2021, Stephen Boyd wrote:
>
> > Quoting Maulik Shah (2021-05-21 04:26:09)
> > > Add device node for SoC sleep stats driver which provides various
> > > low power mode stats.
> > >
> > > Also update the reg size of aoss_qmp device to 0x400.
> > >
> > > Cc: devicetree@vger.kernel.org
> > > Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> > > Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > ---
> > >  arch/arm64/boot/dts/qcom/sc7180.dtsi | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > index 6228ba2..889d04d 100644
> > > --- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > @@ -3215,7 +3215,7 @@
> > >
> > >                 aoss_qmp: power-controller@c300000 {
> > >                         compatible = "qcom,sc7180-aoss-qmp";
> > > -                       reg = <0 0x0c300000 0 0x100000>;
> > > +                       reg = <0 0x0c300000 0 0x400>;
> > >                         interrupts = <GIC_SPI 389 IRQ_TYPE_EDGE_RISING>;
> > >                         mboxes = <&apss_shared 0>;
> > >
> > > @@ -3223,6 +3223,11 @@
> > >                         #power-domain-cells = <1>;
> > >                 };
> > >
> > > +               rpmh-sleep-stats@c3f0000 {
> > > +                       compatible = "qcom,rpmh-sleep-stats";
> > > +                       reg = <0 0x0c3f0000 0 0x400>;
> > > +               };
> > > +
> >
> > Does this need to be in DT? Can the sc7180-aoss-qmp driver use the
> > aux-bus and stick the sleep stats device on there?
> >
>
> The AOSS memory space has N chunks of "message ram", one is used for the
> QMP protocol (presumably the APSS specific one), a different one is used
> for the sleep stats.
>
> I presume we could have come up with a binding for the entire AOSS/AOP
> and then describe (either implicit or explicitly) the QMP and
> debug-stats under that.
>
> But we'd also have to come up with the same container-device for the RPM
> case.

Because the rpm node doesn't include this region of memory today? I
still fail to see why we're changing the existing binding and adding a
DT node for this new region that is basically a debug feature.