Re: [PATCH/RFT] arm64: dts: renesas: r8a7795: Create thermal zone to support IPA

["Niklas Söderlund" <niklas.soderlund@ragnatech.se>]

Hi Keneko-san,

Thanks for your work.

Comments to this patch applies to all patches in this series.

On 2018-12-21 05:49:39 +0900, Yoshihiro Kaneko wrote:
> From: Dien Pham <dien.pham.ry@renesas.com>
> 
> [dien.pham.ry: arm64: dts: r8a7795: Add support IPA for CA53 core]
> 
> Setup a thermal zone driven by SoC temperature sensor.
> Create passive trip points and bind them to CPUFreq cooling
> device that supports power extension.
> 
> In R-Car Gen3, IPA is supportted for only one channel
>  (on H3/M3/M3N board, it is channel THS3). Reason:
>   Currently, IPA controls base on only CPU temperature.
>   And only one thermal channel is assembled closest
>   CPU cores is selected as target of IPA.
>   If other channels are used, IPA controlling is not properly.
> 
> Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
> [gaku.inami.xw: fix the trip temperature for cooling-device]
> [gaku.inami.xw: fix the power coefficient]
> Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
> Signed-off-by: Hien Dang <hien.dang.eb@rvc.renesas.com>
> Signed-off-by: An Huynh <an.huynh.uj@rvc.renesas.com>
> [takeshi.kihara.df: fix W=1 dtc unit_address_vs_reg warnings]
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
> ---
> 
> This patch is based on the devel branch of Simon Horman's renesas tree.
> 
>  arch/arm64/boot/dts/renesas/r8a7795.dtsi | 64 ++++++++++++++------------------
>  1 file changed, 27 insertions(+), 37 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/renesas/r8a7795.dtsi b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> index af9605d..dd52b50 100644
> --- a/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> @@ -155,6 +155,9 @@
>  			power-domains = <&sysc R8A7795_PD_CA57_CPU0>;
>  			next-level-cache = <&L2_CA57>;
>  			enable-method = "psci";
> +			dynamic-power-coefficient = <854>;
> +			cooling-min-level = <0>;
> +			cooling-max-level = <2>;

I can't find any documentation or code which makes use of the 
cooling-min-level and cooling-max-level properties on v5.0-rc1. What is 
the intended usage for these properties?

>  			clocks = <&cpg CPG_CORE R8A7795_CLK_Z>;
>  			operating-points-v2 = <&cluster0_opp>;
>  			capacity-dmips-mhz = <1024>;
> @@ -207,6 +210,10 @@
>  			power-domains = <&sysc R8A7795_PD_CA53_CPU0>;
>  			next-level-cache = <&L2_CA53>;
>  			enable-method = "psci";
> +			#cooling-cells = <2>;
> +			dynamic-power-coefficient = <277>;
> +			cooling-min-level = <0>;
> +			cooling-max-level = <2>;
>  			clocks = <&cpg CPG_CORE R8A7795_CLK_Z2>;
>  			operating-points-v2 = <&cluster1_opp>;
>  			capacity-dmips-mhz = <535>;
> @@ -3098,58 +3105,30 @@
>  			polling-delay-passive = <250>;
>  			polling-delay = <1000>;
>  			thermal-sensors = <&tsc 0>;
> +			sustainable-power = <6313>;
>  
>  			trips {
> -				sensor1_passive: sensor1-passive {
> -					temperature = <95000>;
> -					hysteresis = <1000>;
> -					type = "passive";
> -				};
>  				sensor1_crit: sensor1-crit {
>  					temperature = <120000>;
>  					hysteresis = <1000>;
>  					type = "critical";
>  				};
>  			};
> -
> -			cooling-maps {
> -				map0 {
> -					trip = <&sensor1_passive>;
> -					cooling-device = <&a57_0 4 4>,
> -							 <&a57_1 4 4>,
> -							 <&a57_2 4 4>,
> -							 <&a57_3 4 4>;
> -				};
> -			};
>  		};
>  
>  		sensor_thermal2: sensor-thermal2 {
>  			polling-delay-passive = <250>;
>  			polling-delay = <1000>;
>  			thermal-sensors = <&tsc 1>;
> +			sustainable-power = <6313>;
>  
>  			trips {
> -				sensor2_passive: sensor2-passive {
> -					temperature = <95000>;
> -					hysteresis = <1000>;
> -					type = "passive";
> -				};
>  				sensor2_crit: sensor2-crit {
>  					temperature = <120000>;
>  					hysteresis = <1000>;
>  					type = "critical";
>  				};
>  			};
> -
> -			cooling-maps {
> -				map0 {
> -					trip = <&sensor2_passive>;
> -					cooling-device = <&a57_0 4 4>,
> -							 <&a57_1 4 4>,
> -							 <&a57_2 4 4>,
> -							 <&a57_3 4 4>;
> -				};
> -			};
>  		};
>  
>  		sensor_thermal3: sensor-thermal3 {
> @@ -3158,11 +3137,18 @@
>  			thermal-sensors = <&tsc 2>;
>  
>  			trips {
> -				sensor3_passive: sensor3-passive {
> -					temperature = <95000>;
> +				threshold: trip-point0 {
> +					temperature = <90000>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};

What is the usage of trip-point0? The label threshold is never 
referenced anywhere, or am I missing something?

> +
> +				target: trip-point1 {
> +					temperature = <100000>;
>  					hysteresis = <1000>;
>  					type = "passive";
>  				};
> +
>  				sensor3_crit: sensor3-crit {
>  					temperature = <120000>;
>  					hysteresis = <1000>;
> @@ -3172,11 +3158,15 @@
>  
>  			cooling-maps {
>  				map0 {
> -					trip = <&sensor3_passive>;
> -					cooling-device = <&a57_0 4 4>,
> -							 <&a57_1 4 4>,
> -							 <&a57_2 4 4>,
> -							 <&a57_3 4 4>;
> +					trip = <&target>;
> +					cooling-device = <&a57_0 0 2>;

We have 5 (0-4) cooling states for the A57s on this SoC. Out of 
curiosity why allow states 0-2 here and not force it do more cooling or 
keep the to max cooling (4) as before this change as this is set to a 
trip point with a rather large temperature? Not saying this is wrong 
only curious :-)

> +					contribution = <1024>;
> +				};
> +
> +				map1 {
> +					trip = <&target>;
> +					cooling-device = <&a53_0 0 2>;
> +					contribution = <1024>;
>  				};
>  			};
>  		};
> -- 
> 1.9.1
> 

-- 
Regards,
Niklas Söderlund