i.MX28 watchdog activation in U-Boot and Linux reboot problem

Jocelyn Harvey jocelyn.harvey at vibrosystm.com
Wed May 19 18:14:08 CEST 2021


We wanted a watchdog during the U-Boot process so I added
hw_watchdog_init() and hw_watchdog_reset() functions to U-Boot for my
board. The watchdog timer works fine in U-Boot but now when Linux reboots
it gets stuck on:

[   180.339543] reboot: Restarting system

When the watchdog is not activated, it reboots fine. Even when the watchdog
timer expires it does not reboot, it just hangs.
I tried to activate the watchdog using only the memory write function in
U-Boot which sets the WATCHDOGEN bit in the RTC ctrl register:

mw 0x80056004 0x00000010

(yes, watchdog timer is already set to 60000 ms)
Only that change prevents Linux from rebooting. I don't have any clue on
what can be the cause of the problem.

Any help would be appreciated.


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