Re: [PATCH 9/9] arm64: dts: qcom: sc7280: Update Q6V5 MSS node

From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Sibi Sankar <sibis@codeaurora.org>
Cc: Matthias Kaehlcke <mka@chromium.org>,
	robh+dt@kernel.org, will@kernel.org,
	saiprakash.ranjan@codeaurora.org, ohad@wizery.com,
	agross@kernel.org, mathieu.poirier@linaro.org,
	robin.murphy@arm.com, joro@8bytes.org, p.zabel@pengutronix.de,
	linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, evgreen@chromium.org,
	dianders@chromium.org, swboyd@chromium.org
Subject: Re: [PATCH 9/9] arm64: dts: qcom: sc7280: Update Q6V5 MSS node
Date: Fri, 30 Jul 2021 13:14:28 -0500	[thread overview]
Message-ID: <YQRBhOeHO7LMDdWu@builder.lan> (raw)
In-Reply-To: <c561f99cb281c28581d10e5805190df8@codeaurora.org>

On Wed 30 Jun 15:08 CDT 2021, Sibi Sankar wrote:

> On 2021-06-29 00:35, Matthias Kaehlcke wrote:
> > On Fri, Jun 25, 2021 at 01:17:38AM +0530, Sibi Sankar wrote:
> > > Update MSS node to support MSA based modem boot on SC7280 SoCs.
> > > 
> > > Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
> > > ---
> > >  arch/arm64/boot/dts/qcom/sc7280-idp.dts |  7 +++++++
> > >  arch/arm64/boot/dts/qcom/sc7280.dtsi    | 19 ++++++++++++++++---
> > >  2 files changed, 23 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > b/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > index 191e8a92d153..d66e3ca42ad5 100644
> > > --- a/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > +++ b/arch/arm64/boot/dts/qcom/sc7280-idp.dts
> > > @@ -343,3 +343,10 @@
> > >  		bias-pull-up;
> > >  	};
> > >  };
> > > +
> > > +&remoteproc_mpss {
> > > +	status = "okay";
> > > +	compatible = "qcom,sc7280-mss-pil";
> > > +	iommus = <&apps_smmu 0x124 0x0>, <&apps_smmu 0x488 0x7>;
> > > +	memory-region = <&mba_mem &mpss_mem>;
> > > +};
> > > diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > > b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > > index 56ea172f641f..6d3687744440 100644
> > > --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > > @@ -586,7 +586,8 @@
> > > 
> > >  		remoteproc_mpss: remoteproc@4080000 {
> > >  			compatible = "qcom,sc7280-mpss-pas";
> > > -			reg = <0 0x04080000 0 0x10000>;
> > > +			reg = <0 0x04080000 0 0x10000>, <0 0x04180000 0 0x48>;
> > > +			reg-names = "qdsp6", "rmb";
> > 
> > Binding needs update?
> > 
> > Documentation/devicetree/bindings/remoteproc/qcom,adsp.yaml:
> > 
> >   reg:
> >       maxItems: 1
> > 
> > > 
> > >  			interrupts-extended = <&intc GIC_SPI 264 IRQ_TYPE_EDGE_RISING>,
> > >  					      <&modem_smp2p_in 0 IRQ_TYPE_EDGE_RISING>,
> > > @@ -597,8 +598,11 @@
> > >  			interrupt-names = "wdog", "fatal", "ready", "handover",
> > >  					  "stop-ack", "shutdown-ack";
> > > 
> > > -			clocks = <&rpmhcc RPMH_CXO_CLK>;
> > > -			clock-names = "xo";
> > > +			clocks = <&gcc GCC_MSS_CFG_AHB_CLK>,
> > > +				 <&gcc GCC_MSS_OFFLINE_AXI_CLK>,
> > > +				 <&gcc GCC_MSS_SNOC_AXI_CLK>,
> > > +				 <&rpmhcc RPMH_CXO_CLK>;
> > > +			clock-names = "iface", "offline", "snoc_axi", "xo";
> > 
> > Binding needs update?
> > 
> > Documentation/devicetree/bindings/remoteproc/qcom,adsp.yaml:
> > 
> >   clocks:
> >     items:
> >       - description: XO clock
> >   clock-names:
> >     items:
> >       - const: xo
> 
> qcom,sc7280-mpss-pas compatible requires
> just the xo clock and one reg space whereas
> the qcom,sc7280-mss-pil compatible requires
> the additional clks and reg spaces. We just
> overload properties where re-use is possible
> across boards. Hence it would be wrong to
> list those clks/reg spaces as requirements
> for the pas compatible.
> 

Our decision to describe the platform node as a superset of the
resources needed by the pas and pil variants was never reflected in the
DT bindings; resulting in the issue that the superset doesn't validate
against the pas binding and both bindings are full of platform-specific
conditionals.

To resolve the two issues I think we should split the current binding(s)
in a set of platform-centric bindings, that captures the idea of
describing the superset.

To reduce the duplication - that already exists between the two
bindings - I think we should break those out in a common part.

I'm however fine with not delaying this series further, if we agree that
the end result matches what we would put in a combined qcom,sc7280-mpss
binding.

Regards,
Bjorn