From a00850107eb050bf6427a8f3a0445bce9441b5df Mon Sep 17 00:00:00 2001 From: Doug Anderson Date: Tue, 27 Jan 2015 14:25:16 -0800 Subject: [PATCH] watchdog: dw_wdt: pat the watchdog before enabling it On some dw_wdt implementations the "top" register may be initted to 0 at bootup. In such a case, each "pat" of the watchdog will reset the timer to 0xffff. That's pretty short. The input clock of the wdt can be any of a wide range of values. On an rk3288 system, I've seen the wdt clock be 24.75 MHz. That means each tick is ~40ns and we'll count to 0xffff in ~2.6ms. Because of the above two facts, it's a really good idea to pat the watchdog after initting the "top" register properly and before enabling the watchdog. If you don't then there's no way we'll get the next heartbeat in time. Jisheng Zhang fixed this problem on some dw_wdt versions by using the TOP_INIT feature. However, the dw_wdt on rk3288 doesn't have TOP_INIT so it's a good idea to also pat the watchdog manually. Signed-off-by: Doug Anderson Reviewed-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Reading git-format-patch failed