From d32a874b9b4c1e949ee38be7790f6bf6d6143451 Mon Sep 17 00:00:00 2001 From: Yuri Tikhonov Date: Sun, 6 Apr 2008 19:19:14 +0200 Subject: lwmon5 watchdog: limit trigger rate Limit the rate of h/w watch-dog triggering on the LWMON5 board by the CONFIG_WD_MAX_RATE value. Note that an earlier version of this patch which used microseconds instead of ticks dis not work. The problem was that we used usec2ticks() to convert microseconds into ticks. usec2ticks() uses get_tbclk(), which in turn calls get_sys_info(). It turns out that this function does a lot of prolonged operations (like divisions) which take too much time so we do not trigger the watchdog in time, and it resets the system. Signed-off-by: Yuri Tikhonov --- board/lwmon5/lwmon5.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'board/lwmon5') diff --git a/board/lwmon5/lwmon5.c b/board/lwmon5/lwmon5.c index e5fa25937..b63fbdc0c 100644 --- a/board/lwmon5/lwmon5.c +++ b/board/lwmon5/lwmon5.c @@ -476,6 +476,24 @@ int is_pci_host(struct pci_controller *hose) void hw_watchdog_reset(void) { int val; +#if defined(CONFIG_WD_MAX_RATE) + unsigned long long ct = get_ticks(); + + /* + * Don't allow watch-dog triggering more frequently than + * the predefined value CONFIG_WD_MAX_RATE [ticks]. + */ + if (ct >= gd->wdt_last) { + if ((ct - gd->wdt_last) < CONFIG_WD_MAX_RATE) + return; + } else { + /* Time base counter had been reset */ + if (((unsigned long long)(-1) - gd->wdt_last + ct) < + CONFIG_WD_MAX_RATE) + return; + } + gd->wdt_last = get_ticks(); +#endif /* * Toggle watchdog output -- cgit v1.2.3