Some boards don't work with the rate-limiting done in the generic watchdog_reset() provided by wdt-uclass.
For example, on powerpc, get_timer() ceases working during bootm since interrupts are disabled before the kernel image gets decompressed, and when the decompression takes longer than the watchdog device allows (or enough of the budget that the kernel doesn't get far enough to assume responsibility for petting the watchdog), the result is a non-booting board.
As a somewhat hacky workaround (because DT is supposed to describe hardware), allow specifying hw_margin_ms=0 in device tree to effectively disable the ratelimiting and actually ping the watchdog every time watchdog_reset() is called. For that to work, the "has enough time passed" check just needs to be tweaked a little to allow the now==next_reset case as well.
Suggested-by: Christophe Leroy christophe.leroy@csgroup.eu Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk ---
It's the option I dislike the most (because of the DT abuse), but I also do accept that it's the one with the minimal code impact, and apparently the path of least resistance. So here it is.
drivers/watchdog/wdt-uclass.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c index 0603ffbd36..2687135296 100644 --- a/drivers/watchdog/wdt-uclass.c +++ b/drivers/watchdog/wdt-uclass.c @@ -148,7 +148,7 @@ void watchdog_reset(void)
/* Do not reset the watchdog too often */ now = get_timer(0); - if (time_after(now, next_reset)) { + if (time_after_eq(now, next_reset)) { next_reset = now + reset_period; wdt_reset(gd->watchdog_dev); }