Watchdog timers on OMAP3 boards

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Watchdog timers on OMAP3 boards

(Work in progress)

Overview of this article

This article is meant to be a starting point for people to learn setup the watchdog timer on OMAP3 based boards.

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OMAP3 watchdog overview

There are 3 watch dogs WD1=Secure, WD2=MPU, WD3=IVA. WD1 is either taken care of by ROM (HS/EMU) or not accessible (GP). We need to take care of WD2-MPU or take a PRCM reset. WD3 should not be running and does not generate a PRCM reset.

Watchdog timers under x-loader

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Watchdog timers under u-boot

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Watchdog timers under Linux kernel

$ modprobe omap_wdt
OMAP Watchdog Timer Rev 0x31: initial timeout 60 sec

If enable and tick the watchdog card

$ watchdog-test -e; watchdog-test
Watchdog card enabled.
Watchdog Ticking Away!

after 60 sec NOT resets.

If enable and not tick the watchdog card.

$ watchdog-test -e
Watchdog card enabled.
Watchdog Ticking Away!

after 60 sec resets.

If disable the watchdog card.

$ watchdog-test -d
Watchdog card disabled.

after 60 sec NOT resets unless NOWAYOUT is defined (CONFIG_WATCHDOG_NOWAYOUT)