AM625: Linux Thermal shut down

Hello Tashiro-san,

Koichiro Tashiro said:

But it is not clear how the linux kernel shut off the SoC.

There is a VTM module on AM62x which does the Temperature monitoring. 

Whenever the temperature crosses the critical temperature threshold, the VTM module initiates a warm reset of the SoC. Therefore, it is not the linux kernel but the VTM module which resets the SOC.

Regards,

Nihar Potturu. 

Hi Nihar,

Thanks for your reply. I checked TRM section 6.2.5.5 (VTM section), but it seems VTM only sends alerts or interrupts.
It cannot generate resets. So I guess someone else generates the warm reset,  for example, software reset in ISR.

Thanks and regards,
Koichiro Tashiro

Hello Tashiro-san,

It is not a software generated reset. Please look at the screenshot below attached from 6.3.5.4 section of the AM62x TRM. 

Regards,

Nihar Potturu

Hi Nihar,

I see. Thanks.

FYI, the customer refers to below website and it says "The shutdown action should be always the default and preferred one."
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/Documentation/devicetree/bindings/thermal?id=87f67d1747bc3ce8ace14be99b47d7731041ff03

But we do not take this approach in TI SDK and reboot is used, correct?

Thanks and regards,
Koichiro Tashiro

Could you reply to my last question?

Could you reply this one?

Hi Bin,

Thanks for your reply.

Bin Liu said:

The definition/configuration in kernel device tree k3-am62-thermal.dtsi is just an example, customers can modify it based nn the project requirement, for example, to shutdown or reboot Linux.

The customer wants to know how to shutdown AM62x safely from Linux kernel.
Do you have recommended shutdown sequence?

Thanks and regards,
Koichiro Tashiro

Hi Tashiro-san,

With the default setting in kernel device tree k3-am62-thermal.dtsi, kernel will trigger shutdown sequence when temperature reaches to 105C.