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From: Stephan Gerhold <stephan@gerhold.net>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Loic Poulain <loic.poulain@linaro.org>,
	agross@kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH] arch: arm64: dts: apq8016-dbc: Add missing cpu opps
Date: Fri, 3 Apr 2020 12:09:23 +0200	[thread overview]
Message-ID: <20200403100923.GB2652@gerhold.net> (raw)
In-Reply-To: <20200403013119.GB20625@builder.lan>

On Thu, Apr 02, 2020 at 06:31:19PM -0700, Bjorn Andersson wrote:
> On Thu 02 Apr 01:13 PDT 2020, Stephan Gerhold wrote:
> 
> > Hi,
> > 
> > On Wed, Apr 01, 2020 at 07:50:59PM +0200, Loic Poulain wrote:
> > > The highest cpu frequency opps have been dropped because CPR is not
> > > supported. However, we can simply specify operating voltage so that
> > > they match the max corner voltages for each freq. With that, we can
> > > support up to 1.36Ghz. Ideally, msm8916 CPR should be implemented to
> > > fine tune operating voltages and optimize power consumption.
> > 
> > Thanks for the patch! I was wondering how to enable the higher CPU
> > frequencies for a while now...
> > 
> > I was actually quite excited to see CPR being mainlined for QCS404.
> > If we are trying to add such a workaround (rather than CPR) for MSM8916
> > now, does that mean it's unlikely to see CPR working for MSM8916
> > anytime soon?
> > 
> > AFAICT, there is a WIP branch from Niklas Cassel here:
> > https://git.linaro.org/people/nicolas.dechesne/niklas.cassel/kernel.git/log/?h=cpr-msm8916-mainline
> > but it hasn't been updated for a while. (Not sure if it was working
> > already...)
> > 
> > Can someone explain what is missing to make CPR work for MSM8916?
> > 
> 
> CPR needs to control 3 things; VDD_APC, VDD_MX and MEMACC. On QCS404 it
> seems we don't have to adjust VDD_MX, so the code for this is missing
> from the driver.
> 
> So, afaict, what's missing is that rpmpd.c needs to gain support for
> 8916, then the CPR driver needs to gain a cpr_acc_desc and compatible
> for 8916, it needs to reference the VDDMX power domain and before/after
> we're adjusting the corner of the CPR we need to adjust the MX according
> to the mapping specified in the downstream kernel (i.e.  1->4, 2->5 and
> 3->7).
> 
> 
> Unfortunately, the requirement that VDDMX (VDD_MEM I presume) must be
> higher than VDD_APC most likely needs to be taken into consideration for
> Loic's proposed static voltage scaling as well. Unless VDD_MEM is left
> in Turbo mode from the boot loader I think we need to take VDDMX to
> corner 7 for speeds 998MHz and above (i.e. where we pull VDD_APC to
> 1.35V).
> 

I see! I wonder how hard it would be to add MSM8916 to rpmpd,
looking at previous commits it's mainly setting up a few defines?

If I understand it correctly, the OPPs from rpmpd could then be
referenced as "required-opps" in the CPU OPP table so that VDD_MX is
scaled together with the CPU frequency, and doesn't need to stay at
turbo mode (like in v3 from Loic) the whole time.

Scaling VDD_APC and VDD_MEM to the maximum necessary for the selected
CPU frequency sounds like a good (temporary) solution to me until we
have full CPR eventually at some point.

Thanks,
Stephan

> > One other minor comment/question below.
> > 
> > > 
> > > This patch:
> > > - Adds missing opps and corresponding target voltages to msm8916.dtsi.
> > > - Adds cpu-supply to apq8016-sbc.dtsi (board level info).
> > > - Adds pm8916 spmi regulator node to pm8916.dtsi.
> > > 
> > > Tested with a dragonboard-410c.
> > > 
> > > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> > > ---
> > >  arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi | 24 ++++++++++++++++++++++++
> > >  arch/arm64/boot/dts/qcom/msm8916.dtsi     | 24 ++++++++++++++++++++++++
> > >  arch/arm64/boot/dts/qcom/pm8916.dtsi      |  6 ++++++
> > >  3 files changed, 54 insertions(+)
> > > 
> > > diff --git a/arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi b/arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi
> > > index 037e26b..f1c1216 100644
> > > --- a/arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi
> > > @@ -560,6 +560,30 @@
> > >  	qcom,mbhc-vthreshold-high = <75 150 237 450 500>;
> > >  };
> > >  
> > > +&spm_regulators {
> > > +	vdd_cpu: s2 {
> > > +		regulator-always-on;
> > > +		regulator-min-microvolt = <1050000>;
> > > +		regulator-max-microvolt = <1350000>;
> > > +	};
> > > +};
> > > +
> > > +&CPU0 {
> > > +	cpu-supply = <&vdd_cpu>;
> > > +};
> > > +
> > > +&CPU1 {
> > > +	cpu-supply = <&vdd_cpu>;
> > > +};
> > > +
> > > +&CPU2 {
> > > +	cpu-supply = <&vdd_cpu>;
> > > +};
> > > +
> > > +&CPU3 {
> > > +	cpu-supply = <&vdd_cpu>;
> > > +};
> > > +
> > 
> > I'm a bit confused about the separation here. The cpu-supply is defined
> > in the board-specific device tree, yet the voltages are set in the
> > common device tree below.
> > 
> > Is it even possible that the CPU is supplied by something other than S2
> > and if yes, how likely is this?
> > 
> > I'm asking because I have two other MSM8916 devices in mainline
> > (and a few more pending upstreaming), and it seems like I would need to
> > duplicate this into each of them.
> > 
> > Thanks,
> > Stephan
> > 
> > >  &smd_rpm_regulators {
> > >  	vdd_l1_l2_l3-supply = <&pm8916_s3>;
> > >  	vdd_l5-supply = <&pm8916_s3>;
> > > diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
> > > index 9f31064..9805af0 100644
> > > --- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
> > > @@ -342,15 +342,39 @@
> > >  
> > >  		opp-200000000 {
> > >  			opp-hz = /bits/ 64 <200000000>;
> > > +			opp-microvolt = <1050000>;
> > >  		};
> > >  		opp-400000000 {
> > >  			opp-hz = /bits/ 64 <400000000>;
> > > +			opp-microvolt = <1050000>;
> > > +		};
> > > +		opp-533330000 {
> > > +			opp-hz = /bits/ 64 <533330000>;
> > > +			opp-microvolt = <1150000>;
> > >  		};
> > >  		opp-800000000 {
> > >  			opp-hz = /bits/ 64 <800000000>;
> > > +			opp-microvolt = <1150000>;
> > >  		};
> > >  		opp-998400000 {
> > >  			opp-hz = /bits/ 64 <998400000>;
> > > +			opp-microvolt = <1350000>;
> > > +		};
> > > +		opp-1094400000 {
> > > +			opp-hz = /bits/ 64 <1094400000>;
> > > +			opp-microvolt = <1350000>;
> > > +		};
> > > +		opp-1152000000 {
> > > +			opp-hz = /bits/ 64 <1152000000>;
> > > +			opp-microvolt = <1350000>;
> > > +		};
> > > +		opp-1209600000 {
> > > +			opp-hz = /bits/ 64 <1209600000>;
> > > +			opp-microvolt = <1350000>;
> > > +		};
> > > +		opp-1363200000 {
> > > +			opp-hz = /bits/ 64 <1363200000>;
> > > +			opp-microvolt = <1350000>;
> > >  		};
> > >  	};
> > >  
> > > diff --git a/arch/arm64/boot/dts/qcom/pm8916.dtsi b/arch/arm64/boot/dts/qcom/pm8916.dtsi
> > > index 0bcdf04..c9b9c4f 100644
> > > --- a/arch/arm64/boot/dts/qcom/pm8916.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/pm8916.dtsi
> > > @@ -157,5 +157,11 @@
> > >  			vdd-micbias-supply = <&pm8916_l13>;
> > >  			#sound-dai-cells = <1>;
> > >  		};
> > > +
> > > +		spm_regulators: spm_regulators  {
> > > +			compatible = "qcom,pm8916-regulators";
> > > +			#address-cells = <1>;
> > > +			#size-cells = <1>;
> > > +		};
> > >  	};
> > >  };
> > > -- 
> > > 2.7.4
> > > 

  reply	other threads:[~2020-04-03 10:09 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-01 17:50 [PATCH] arch: arm64: dts: apq8016-dbc: Add missing cpu opps Loic Poulain
2020-04-01 23:46 ` Bjorn Andersson
2020-04-02  8:13 ` Stephan Gerhold
2020-04-02  9:58   ` Loic Poulain
2020-04-03  1:31   ` Bjorn Andersson
2020-04-03 10:09     ` Stephan Gerhold [this message]
2020-04-03 18:00       ` Stephan Gerhold
2020-04-23  4:55         ` Bjorn Andersson
2020-04-26 12:31           ` Stephan Gerhold
2020-05-06 21:18             ` Stephan Gerhold
2020-05-07  5:34               ` Bjorn Andersson
2020-05-08 12:08                 ` Ulf Hansson
2020-05-08 13:42                   ` Stephan Gerhold
2020-05-11  5:29                   ` Viresh Kumar
2020-05-07 10:46               ` Stephan Gerhold
2020-05-21 19:18                 ` Stephan Gerhold
2020-05-23 12:08                   ` Stephan Gerhold
2020-05-27 20:47                     ` Georgi Djakov
2020-05-25 15:32           ` Niklas Cassel
2020-05-25 16:36             ` Stephan Gerhold
2020-05-25 19:44               ` Niklas Cassel
2020-05-26  8:59                 ` Stephan Gerhold
2020-05-26 15:54                   ` Niklas Cassel
2020-05-26 20:54                     ` Stephan Gerhold
2020-05-27 10:39                       ` Niklas Cassel
2020-05-27 12:04                         ` Stephan Gerhold
2020-05-27 12:59                           ` Niklas Cassel
2020-05-27 20:56                             ` Stephan Gerhold
2020-05-27 23:10                               ` Niklas Cassel
2020-05-28 13:32                                 ` Stephan Gerhold
2020-05-28  4:44                           ` Viresh Kumar
2020-04-28 20:04 ` Amit Kucheria

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