AM6442: Linux Watchdog

Luka Kustura

Part Number: AM6442

Hello,

related to the previous thread, we are investigating the reset behaviour of the Linux to not interrupt critical firmware running on R5F cores. In this case the watchdogs are interresting as reset cause.

What I have found out so far:

There is no watchdog-based SoC reset in Linux
A non-maskable Interrupt is routed to the MCU ESM, when watchdog timeouts

Can you approve those findings?

Now the question is, how can we use this interrupt on R5F side to reset the whole device when Linux has crashed?
How can we reroute the interrupt to the MAIN ESM, which is accessable by the R5F cores?

Thank you.

Best regards,
Luka

4 days ago

0 Vinuchandran A V 4 days ago

TI__Expert 6780 points

Hi Luca,

Luka Kustura said:
There is no watchdog-based SoC reset in Linux

A non-maskable Interrupt is routed to the MCU ESM, when watchdog timeouts

This is probably only half true.

The Linux rti-wdt driver only services and times out the RTI, and it doesn’t reset the SoC itself. On AM64x a watchdog timeout generates an event routed to the NMI and the ESM, and the SoC can only be reset from the ESM module.

But, in the stock SDK, a Linux watchdog expiry does reset the board.

For more information on how to configure ESM, refer the following FAQs.

1. [FAQ] AM64X/ AM62X : How to Reset the SOC when WDT timer expires in AM64X and AM62X?

2. [FAQ] AM64X/AM62X/AM62AX : Configuring the ESM module from SDL and setting the ESM Bit Fields to enable the ESM Error events

Regards,
Vinu

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AM6442: Linux Watchdog