u-boot leaves watchdog enabled by default

[Chris Packham]

On Tue, 15 Sep 2020, 7:54 PM Michael Walle, <michael at walle.cc> wrote:

> Am 2020-09-15 09:44, schrieb Rayagonda Kokatanur:
> > On Tue, Sep 15, 2020 at 12:56 PM Michael Walle <michael at walle.cc>
> > wrote:
> >>
> >> Hi Stefan,
> >>
> >> it appears that since commit 06985289d45 ("watchdog: Implement generic
> >> watchdog_reset() version") - by default - the first watchdog is
> >> started
> >> unconditionally if CONFIG_WDT is set but never stopped before booting
> >> the operating system.
> >>
> >> Shouldn't it also be stopped uncondionally? What's worse is that on
> >> one
> >> board/arch the watchdog is stopped in arch_preboot_os() which is never
> >> called in the bootefi case. So even if I'd do a workaround and stop it
> >> manually in my board code, I couldn't do that consistently for
> >> bootm/bootefi.
> >>
> >> Or am I missing something here?
> >
> > Define CONFIG_WATCHDOG.
> > This takes care of resetting wdt.
>
> Yes as along as you're inside the bootloader, but when u-boot hands
> control over the OS the watchdog is not serviced anymore; which wouldn't
> be a problem per se, but it is enabled unconditionally by u-boot.
>

Just to add some data. At $dayjob we use this behaviour as a failsafe to
make sure our userspace gets to a point where it is servicing the watchdog.
That said having a leave-wdt-running environment variable would work for
our use case.

>