Re: [PATCH] arm64: dts: allwinner: a100: Add CPU thermal trips and cooling maps

[Andre Przywara <andre.przywara@arm.com>]

Hi Rajan,

many thanks for sending this!

On 11/3/26 10:09, Rajan Yadav via B4 Relay wrote:
> From: Rajan Yadav <rajanyadav0307@gmail.com>
> 
> The CPU thermal zone in sun50i-a100.dtsi has a sensor but no trip
> points, so nothing throttles the CPU as it heats up and nothing shuts
> the system down before it overheats. On a KickPi K5C (A133) without a
> heatsink, the CPU reaches 90 C within minutes of full load.
> 
> Add a passive trip at 90 C that throttles all four cores through
> cpufreq, and a critical trip at 110 C, using the same layout as
> sun50i-h6.dtsi.
> 
> The temperatures come from the Allwinner BSP (sun50iw10p1.dtsi). The
> BSP drives this zone with the power allocator governor: control starts
> at 70 C, the target is 90 C, and 110 C is critical. The power
> allocator needs a power model of the CPUs (dynamic-power-coefficient),
> which the A100 does not have in mainline, so here the 90 C target
> becomes a step_wise passive trip, and the 110 C critical trip is kept.
> 110 C is also the highest working junction temperature in the
> recommended operating conditions of the A133 datasheet (rev 1.5,
> table 5-2). The absolute maximum is 125 C.

Thanks for the explaining where the temperature values come from!

> The GPU and DDR zones are left without trips, as in the BSP.
> 
> Polling stays disabled: the sensor raises an interrupt every 250 ms
> and the driver updates the zone from it, as on the H6.
> 
> Tested on a KickPi K5C (A133, no heatsink):
> - one hour of full load on all cores held the CPU at about 90 C, with
>    short throttling to 1.32 GHz
> - with thermal emulation, a rising temperature lowers the limit one
>    OPP at a time down to 408 MHz, the limit is released below 88 C, and
>    111 C triggers the hardware protection shutdown
> 
> Signed-off-by: Rajan Yadav <rajanyadav0307@gmail.com>

Looks good to me, compared to what we have in the H6 and H616, and 
confirming the 110C number from the datasheet.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

P.S. Since you have a device and have been looking at this: can you 
check the CPU speed bin selection? I think it's quite wrong for the 
A133. The original contribution was just for the A100, using A100 
specific ID values. I briefly checked and think they don't make too much 
sense on the A133. Also definitely the OPPs are for the A100 only: we 
are surely missing the nominal 1.6GHz OPP for the A133, and I think the 
other parts (A133P) go even higher.
There are several lists and numbers floating around on the net, and I 
think BSP code should have a better way to identify the bins and dies.
I would be grateful if you could dig into this and come up with OPP 
updates. Many thanks!
> ---
> arm64: dts: allwinner: a100: Add CPU thermal trips and cooling maps
> ---
>   arch/arm64/boot/dts/allwinner/sun50i-a100.dtsi | 29 ++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a100.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a100.dtsi
> index ba6020989..fce91dc2c 100644
> --- a/arch/arm64/boot/dts/allwinner/sun50i-a100.dtsi
> +++ b/arch/arm64/boot/dts/allwinner/sun50i-a100.dtsi
> @@ -8,6 +8,7 @@
>   #include <dt-bindings/clock/sun50i-a100-r-ccu.h>
>   #include <dt-bindings/reset/sun50i-a100-ccu.h>
>   #include <dt-bindings/reset/sun50i-a100-r-ccu.h>
> +#include <dt-bindings/thermal/thermal.h>
>   
>   / {
>   	interrupt-parent = <&gic>;
> @@ -24,6 +25,7 @@ cpu0: cpu@0 {
>   			reg = <0x0>;
>   			enable-method = "psci";
>   			clocks = <&ccu CLK_CPUX>;
> +			#cooling-cells = <2>;
>   		};
>   
>   		cpu1: cpu@1 {
> @@ -32,6 +34,7 @@ cpu1: cpu@1 {
>   			reg = <0x1>;
>   			enable-method = "psci";
>   			clocks = <&ccu CLK_CPUX>;
> +			#cooling-cells = <2>;
>   		};
>   
>   		cpu2: cpu@2 {
> @@ -40,6 +43,7 @@ cpu2: cpu@2 {
>   			reg = <0x2>;
>   			enable-method = "psci";
>   			clocks = <&ccu CLK_CPUX>;
> +			#cooling-cells = <2>;
>   		};
>   
>   		cpu3: cpu@3 {
> @@ -48,6 +52,7 @@ cpu3: cpu@3 {
>   			reg = <0x3>;
>   			enable-method = "psci";
>   			clocks = <&ccu CLK_CPUX>;
> +			#cooling-cells = <2>;
>   		};
>   	};
>   
> @@ -659,6 +664,30 @@ cpu-thermal {
>   			polling-delay-passive = <0>;
>   			polling-delay = <0>;
>   			thermal-sensors = <&ths 0>;
> +
> +			trips {
> +				cpu_alert: cpu-alert {
> +					temperature = <90000>;
> +					hysteresis = <2000>;
> +					type = "passive";
> +				};
> +
> +				cpu-crit {
> +					temperature = <110000>;
> +					hysteresis = <0>;
> +					type = "critical";
> +				};
> +			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&cpu_alert>;
> +					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>;
> +				};
> +			};
>   		};
>   
>   		ddr-thermal {
> 
> ---
> base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4
> change-id: 20261103-a100-thermal-trips-be14e8047b0a
> 
> Best regards,
> --
> Rajan Yadav <rajanyadav0307@gmail.com>