AM625: Thermal management to avoid thermal runaway

Hi Tashiro-san,

Yes, kernel thermal framework provides the capabilities to cool down the system once the temperature raises to a defined threshold. There are 4 types of cooling down actions defined by the kernel thermal framewrok: active, passive, hot, and critical. The details are explained in the kernel device tree thermal binding doc:

<kernel source>/Documentation/devicetree/bindings/thermal/thermal-zones.yaml

Since CPU dynamic frequency scaling was just enabled in kernel recently, the "passive" cooling down (reducing CPU frequency) has not be validated in the SDK yet. The currently setting on SK-AM62 is to reboot Linux when the thermal reach to the threshold.

Hi Tashiro-san,

Koichiro Tashiro said:

For example, is it possible to detect high side threshold by sensor interrupt and change CPU frequency, etc. for cool down?

Yes, it is possible to cool down by changing the CPU frequency in the SDK. Please refer to the J7200 thermal device tree configuration:

<kernel source>/arch/arm64/boot/dts/ti/k3-j7200-thermal.dtsi