On Sa, 2020-10-31 at 12:42 +0100, H. Nikolaus Schaller wrote:
Hi,
Now after becoming awake, I start to remember some more details and I have hacked the Letux kernel code a little...
- the WDT was originally enabled by default in U-Boot
If I remember correctly our first experiments >5 years ago, this has the negative effect that after entering the u-boot console you just have 1 minute to type commands. So I think we have a patch in u-boot to disable it.
Okay that's not an issue IMHO, as no one needs to enter commands on U- Boot normally.
- the driver requires a "compatible" entry which is missing
I have added one to omap5-board-common.dtsi. See attached patch.
Thanks.
- I do not know how to control the watchdog1 timeout (struct
watchdog_device) from user-space and how enable the watchdog1. This has to be evaluated how it should work.
Okay, there should (hopefully) something about this in the datasheet.
- Note that there is also an OMAP watchdog0:
[ 4.023269] omap_wdt: OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec which raises the question why it is not sufficient in an OMAP5 lockup situation. Maybe the lockup also stops the watchdog clock or the action that should be taken after timeout.
I can imagine that the watchdog freezes as well if the OMAP5 locks up :)