From 5973bee46fe66db94fab198979dec87f263fc2a8 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Tue, 21 Jul 2009 00:40:46 +0200 Subject: [PATCH] [WATCHDOG] Fix COH 901 327 watchdog enablement Since the COH 901 327 found in U300 is clocked at 32 kHz we need to wait for the interrupt clearing flag to propagate through hardware in order not to accidentally fire off any interrupts when we enable them. Signed-off-by: Linus Walleij Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/coh901327_wdt.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/watchdog/coh901327_wdt.c b/drivers/watchdog/coh901327_wdt.c index fecb307..aec7cef 100644 --- a/drivers/watchdog/coh901327_wdt.c +++ b/drivers/watchdog/coh901327_wdt.c @@ -18,6 +18,7 @@ #include #include #include +#include #define DRV_NAME "WDOG COH 901 327" @@ -92,6 +93,8 @@ static struct clk *clk; static void coh901327_enable(u16 timeout) { u16 val; + unsigned long freq; + unsigned long delay_ns; clk_enable(clk); /* Restart timer if it is disabled */ @@ -102,6 +105,14 @@ static void coh901327_enable(u16 timeout) /* Acknowledge any pending interrupt so it doesn't just fire off */ writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE, virtbase + U300_WDOG_IER); + /* + * The interrupt is cleared in the 32 kHz clock domain. + * Wait 3 32 kHz cycles for it to take effect + */ + freq = clk_get_rate(clk); + delay_ns = (1000000000 + freq - 1) / freq; /* Freq to ns and round up */ + delay_ns = 3 * delay_ns; /* Wait 3 cycles */ + ndelay(delay_ns); /* Enable the watchdog interrupt */ writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR); /* Activate the watchdog timer */ -- 1.8.2.3