On 24/02/2020 17:54, Ondrej Jirman wrote:
> This enables passive cooling by down-regulating CPU voltage
> and frequency.
>
> For the trip points, I used values from the BSP code directly.
>
> The critical trip point value is 30°C above the maximum recommended
> ambient temperature (70°C) for the SoC from the datasheet, so there's
> some headroom even at such a high ambient temperature.
>
> Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
> ---
> arch/arm/boot/dts/sun8i-a83t.dtsi | 60 +++++++++++++++++++++++++++----
> 1 file changed, 54 insertions(+), 6 deletions(-)
>
> v2:
> - added more detail to the commit description
>
> diff --git a/arch/arm/boot/dts/sun8i-a83t.dtsi b/arch/arm/boot/dts/sun8i-a83t.dtsi
> index 74ac7ee9383cf..53c2b6a836f27 100644
> --- a/arch/arm/boot/dts/sun8i-a83t.dtsi
> +++ b/arch/arm/boot/dts/sun8i-a83t.dtsi
> @@ -72,7 +72,7 @@ cpu0: cpu@0 {
> #cooling-cells = <2>;
> };
>
> - cpu@1 {
> + cpu1: cpu@1 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C0CPUX>;
> @@ -83,7 +83,7 @@ cpu@1 {
> #cooling-cells = <2>;
> };
>
> - cpu@2 {
> + cpu2: cpu@2 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C0CPUX>;
> @@ -94,7 +94,7 @@ cpu@2 {
> #cooling-cells = <2>;
> };
>
> - cpu@3 {
> + cpu3: cpu@3 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C0CPUX>;
> @@ -116,7 +116,7 @@ cpu100: cpu@100 {
> #cooling-cells = <2>;
> };
>
> - cpu@101 {
> + cpu101: cpu@101 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C1CPUX>;
> @@ -127,7 +127,7 @@ cpu@101 {
> #cooling-cells = <2>;
> };
>
> - cpu@102 {
> + cpu102: cpu@102 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C1CPUX>;
> @@ -138,7 +138,7 @@ cpu@102 {
> #cooling-cells = <2>;
> };
>
> - cpu@103 {
> + cpu103: cpu@103 {
> compatible = "arm,cortex-a7";
> device_type = "cpu";
> clocks = <&ccu CLK_C1CPUX>;
> @@ -1188,12 +1188,60 @@ cpu0_thermal: cpu0-thermal {
> polling-delay-passive = <0>;
> polling-delay = <0>;
> thermal-sensors = <&ths 0>;
> +
> + trips {
> + cpu0_hot: cpu-hot {
> + temperature = <80000>;
> + hysteresis = <2000>;
> + type = "passive";
> + };
> +
> + cpu0_very_hot: cpu-very-hot {
> + temperature = <100000>;
> + hysteresis = <0>;
> + type = "critical";
> + };
> + };
> +
> + cooling-maps {
> + cpu-hot-limit {
> + trip = <&cpu0_hot>;
> + cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> + };
> + };
> };
>
> cpu1_thermal: cpu1-thermal {
> polling-delay-passive = <0>;
No polling to mitigate?
> polling-delay = <0>;
> thermal-sensors = <&ths 1>;
> +
> + trips {
> + cpu1_hot: cpu-hot {
> + temperature = <80000>;
> + hysteresis = <2000>;
> + type = "passive";
I'm curious, can you really reach this temperature with a cortex-a7
running at 1.2GHz max?
> + };
> +
> + cpu1_very_hot: cpu-very-hot {
> + temperature = <100000>;
> + hysteresis = <0>;
> + type = "critical";
> + };
> + };
> +
> + cooling-maps {
> + cpu-hot-limit {
> + trip = <&cpu1_hot>;
> + cooling-device = <&cpu100 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu101 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu102 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> + <&cpu103 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> + };
> + };
> };
>
> gpu_thermal: gpu-thermal {
>
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