[U-Boot] enabling watchdog timer

[Alessandro Rubini]

> I'm using an at91sam9260ek board. I configured a watchdog driver in my
> kernel only to find out that u-boot turns it off.

The problem with 9260 and friends is that the watchdog can be
configured once only.  In my experience the best thing to do is
leaving it unconfigured (it triggers in 13 seconds, more or less) so
the kernel or application can configure it (either enable at a
different timeout or or disable it).

> The big top level README files says I need to define CONFIG_WATCHDOG, but
> [...]

I think you should grep around yourself. I did it with 1.1.5 and things
are different now.

> Also in 'README.at91', reference is made to make sure that the watchdog in
> AT91Bootstrap is not disabled.  Where's 'AT91Bootstrap'?

It is a separate package. An initial program loader that loads the
real boot loader from nand or dataflash. You may be using it or not,
you have to check that on your setup.  If u-boot is not programmed
to offset 0 of your nand, you most likely have at91boot there.

The stock sources of at91boot disable the watchdog, so you most likely
want to change it.

I used http://www.at91.com/repFichier/Project-209/at91bootstrap-2.3.tar.bz2
and removed line 84 of board/at91sam9260ek/at91sam9260ek.c .

After that, you'll want u-boot to trigger the watchdog without
configuring it, unless you need a shorter timeout since the beginning.

Hope this helps.
/alessandro