TMDS64GPEVM: Watchdog Timer Does Not Reset The Device

Onur Bay

Part Number: TMDS64GPEVM

Hi,

I'm trying to test watchdog timer functionality in Linux. I followed this steps and successfully enabled watchdog devices. After I load the kernel module (rti-wdt) I can see two watchdog timers (/dev/watchdog0, /dev/watchdog1) were registered under /dev.

After loading the kernel module I track the time left to reset the device using WDIOC_GETTIMELEFT ioctl call. I can see that timer starts from 60 seconds and reaches to 0. But reset does not occur when timer reaches 0 seconds.

What can I do to reset the device when watchdog does not pinged in the specified time window on linux?

over 2 years ago

+1 Randolph Sapp over 2 years ago

TI__Intellectual 1480 points

Hello Onur,

By default the interrupt triggered by the watchdog isn't mapped such that it can trigger a board reset. The following FAQ goes over how to route this interrupt to the ESM and trigger a reset using a control MMR using the MCU SDK.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1283237/faq-am64x-am62x-how-to-reset-the-soc-when-wdt-timer-expires-in-am64x-and-am62x

Under linux this can be achieved fairly easily with the watchdog subsystem, though this does rely on you getting to the kernel before it behaves the same. You'll just have to add a restart function to the watchdog_ops table in rti_wdt.c. This function will be called to reset/restart the device when the timer expires. In this function you should be able to use the same control MMR method described above to perform a warm reset.

Further documentation for the watchdog subsystem can be found here:

https://docs.kernel.org/watchdog/watchdog-kernel-api.html

Regards,

Randolph

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TMDS64GPEVM: Watchdog Timer Does Not Reset The Device