watchdog: imxwd: suspend watchdog timer in low power mode

Watchdog timer should be disabled in low power mode. The problem that
was observed was that when the watchdog is started from barebox, kernel
driver doesn't do its own setup again and in turn this bit is left
unset. Moreover, this bit is write-once and has to be set before
enabling the watchdog, leaving responsibility for proper setup to a
party first using the watchdog timer (e.g. bootloader). Issue manifests
itself later on, when device enters low power mode (e.g. suspend) for
more amount of time than what is maximum watchdog timeout (128s). After
that period of time, device will not recover ever as there is no service
patting the watchdog (CPU is suspended). This means that the device can
hang in suspend mode or it performs an unexpected reset.

Thus to avoid suspend/resume problems when watchdog is started already
in the bootloader, align bootloader driver settings with kernel settings.
Kernel driver has been already setting this bit since 2014.

Signed-off-by: Andrej Picej <andrej.picej@norik.com>
Link: https://lore.barebox.org/20211216122653.2335949-1-andrej.picej@norik.com
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

0 files changed, 0 insertions, 0 deletions