linux-kernel - Re: [PATCH v1 7/7] arm64: dts: sdm845: wireup the thermal trip points to cpufreq

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Date:   Wed, 9 Jan 2019 18:22:17 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Amit Kucheria <amit.kucheria@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        bjorn.andersson@...aro.org, viresh.kumar@...aro.org,
        edubezval@...il.com, andy.gross@...aro.org, tdas@...eaurora.org,
        swboyd@...omium.org, dianders@...omium.org,
        David Brown <david.brown@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH v1 7/7] arm64: dts: sdm845: wireup the thermal trip
 points to cpufreq

Hi Amit,

On Thu, Jan 10, 2019 at 05:30:56AM +0530, Amit Kucheria wrote:
> Since the big and little cpus are in the same frequency domain, use all
> of them for mitigation in the cooling-map. At the lower trip points we
> restrict ourselves to throttling only a few OPPs. At higher trip
> temperatures, allow ourselves to be throttled to any extent.
> 
> Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
> ---
>  arch/arm64/boot/dts/qcom/sdm845.dtsi | 145 +++++++++++++++++++++++++++
>  1 file changed, 145 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> index 29e823b0caf4..cd6402a9aa64 100644
> --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> @@ -13,6 +13,7 @@
>  #include <dt-bindings/reset/qcom,sdm845-aoss.h>
>  #include <dt-bindings/soc/qcom,rpmh-rsc.h>
>  #include <dt-bindings/clock/qcom,gcc-sdm845.h>
> +#include <dt-bindings/thermal/thermal.h>
>  
>  / {
>  	interrupt-parent = <&intc>;
> @@ -99,6 +100,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x0>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_0>;
>  			L2_0: l2-cache {
>  				compatible = "cache";
> @@ -114,6 +116,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x100>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;

This is not needed (also applies to other for other non-policy
cores). A single cpufreq device is created per frequency domain /
cluster, hence a single cooling device is registered per cluster,
which IMO makes sense given that the CPUs of a cluster can't change
their frequencies independently.

>  			next-level-cache = <&L2_100>;
>  			L2_100: l2-cache {
>  				compatible = "cache";
> @@ -126,6 +129,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x200>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_200>;
>  			L2_200: l2-cache {
>  				compatible = "cache";
> @@ -138,6 +142,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x300>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_300>;
>  			L2_300: l2-cache {
>  				compatible = "cache";
> @@ -150,6 +155,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x400>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_400>;
>  			L2_400: l2-cache {
>  				compatible = "cache";
> @@ -162,6 +168,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x500>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_500>;
>  			L2_500: l2-cache {
>  				compatible = "cache";
> @@ -174,6 +181,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x600>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_600>;
>  			L2_600: l2-cache {
>  				compatible = "cache";
> @@ -186,6 +194,7 @@
>  			compatible = "qcom,kryo385";
>  			reg = <0x0 0x700>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
>  			next-level-cache = <&L2_700>;
>  			L2_700: l2-cache {
>  				compatible = "cache";
> @@ -1703,6 +1712,23 @@
>  					type = "critical";
>  				};
>  			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&cpu_alert0>;
> +					cooling-device = <&CPU0 THERMAL_NO_LIMIT 4>,
> +							 <&CPU1 THERMAL_NO_LIMIT 4>,

As per above, there are no cooling devices for CPU1-3 and CPU5-7.

Cheers

Matthias