From 081d83a3393f65adc94fc4240b9926be3054f9dc Mon Sep 17 00:00:00 2001 From: Nick Bowler <nbowler@elliptictech.com> Date: Fri, 15 Jul 2011 11:04:02 -0400 Subject: watchdog: sp805: Flush posted writes in enable/disable. There are no reads in these functions, so if MMIO writes are posted, the writes in enable/disable may not have completed by the time these functions return. If the functions run from different CPUs, it's in theory possible for the writes to be interleaved, which would be disastrous for this driver. At the very least, we need an mmiowb() before releasing the lock, but since it seems desirable for the watchdog timer to be actually stopped or reset when these functions return, read the lock register to force the writes out. Signed-off-by: Nick Bowler <nbowler@elliptictech.com> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> --- drivers/watchdog/sp805_wdt.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/watchdog') diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c index c1e099aa57f3..cc2cfbe33b30 100644 --- a/drivers/watchdog/sp805_wdt.c +++ b/drivers/watchdog/sp805_wdt.c @@ -134,6 +134,8 @@ static void wdt_enable(void) writel(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL); writel(LOCK, wdt->base + WDTLOCK); + /* Flush posted writes. */ + readl(wdt->base + WDTLOCK); spin_unlock(&wdt->lock); } @@ -146,6 +148,8 @@ static void wdt_disable(void) writel(0, wdt->base + WDTCONTROL); writel(LOCK, wdt->base + WDTLOCK); + /* Flush posted writes. */ + readl(wdt->base + WDTLOCK); spin_unlock(&wdt->lock); } -- cgit v1.2.1