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Date: Sat, 20 Sep 2014 06:51:56 -0700 From: Guenter Roeck <linux@...ck-us.net> To: Jisheng Zhang <jszhang@...vell.com>, wim@...ana.be CC: linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org Subject: Re: [PATCH 1/2] watchdog: dw_wdt: restart the counter immediately after enabling WDT On 09/18/2014 11:29 PM, Jisheng Zhang wrote: > The TOP_INIT may be zero, so the timeout period may be very short after > initialization is done, thus the system may be reset soon after enabling. > We fix this problem by restarting the counter immediately after enabling > WDT. > > Signed-off-by: Jisheng Zhang <jszhang@...vell.com> > --- > drivers/watchdog/dw_wdt.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index 9f21029..ad0619d 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -146,6 +146,7 @@ static int dw_wdt_open(struct inode *inode, struct file *filp) > dw_wdt_set_top(DW_WDT_MAX_TOP); > writel(WDOG_CONTROL_REG_WDT_EN_MASK, > dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > + dw_wdt_keepalive(); > } > > dw_wdt_set_next_heartbeat(); > After getting access to the datasheet, I concluded that this fix is wrong or at least more risky than necessary. The datasheet states that top_init, ie bit 4-7 of the wdt_torr register, needs to be initialized with the desired timeout period prior to enabling the watchdog. dw_wdt_set_top() sets it to 0 instead, ie to the lowest possible timeout period. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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