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Date: Mon, 18 Jan 2016 23:11:14 -0800 From: Guenter Roeck <linux@...ck-us.net> To: Viresh Kumar <viresh.kumar@...aro.org>, Sandeep Tripathy <tripathy@...adcom.com> Cc: wim@...ana.be, linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org, bcm-kernel-feedback-list@...adcom.com Subject: Re: [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset On 01/18/2016 10:53 PM, Viresh Kumar wrote: > On 19-01-16, 11:34, Sandeep Tripathy wrote: >> sp805 wdt asserts interrupt for the first expiry and > > Why an extra space before sp805 ? > >> reloads the counter. If wdt interrupt is set and count >> reaches zero then wdt reset event is generated.To get > > Add space after full-stop. > >> wdt reset at t timeout the driver loads wdt counter > > Keep t and t/2 in single quotes, its hardly readable otherwise. > >> with t/2. A ping before t second *should* prevent wdt >> reset. Currently if ping is done after t/2 sec then >> wdt interrupt condition gets set. On the next countdown >> of loadval wdt reset event occurs eventhough wdt was >> reloaded before the set timeout t. >> >> This patch clears the interrupt condition on ping. > > Why extra spaces before 'This'? > >> >> Signed-off-by: Sandeep Tripathy <tripathy@...adcom.com> >> --- >> drivers/watchdog/sp805_wdt.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c >> index 01d8162..e7a715e 100644 >> --- a/drivers/watchdog/sp805_wdt.c >> +++ b/drivers/watchdog/sp805_wdt.c >> @@ -139,12 +139,11 @@ static int wdt_config(struct watchdog_device *wdd, bool ping) >> >> writel_relaxed(UNLOCK, wdt->base + WDTLOCK); >> writel_relaxed(wdt->load_val, wdt->base + WDTLOAD); >> + writel_relaxed(INT_MASK, wdt->base + WDTINTCLR); >> >> - if (!ping) { >> - writel_relaxed(INT_MASK, wdt->base + WDTINTCLR); >> + if (!ping) >> writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + >> WDTCONTROL); >> - } >> >> writel_relaxed(LOCK, wdt->base + WDTLOCK); > > If I read the TRM properly, then you don't need to load the WDTLOAD > register on ping and so your change can be written as: > > diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c > index 01d816251302..42e1ec86532d 100644 > --- a/drivers/watchdog/sp805_wdt.c > +++ b/drivers/watchdog/sp805_wdt.c > @@ -138,10 +138,10 @@ static int wdt_config(struct watchdog_device *wdd, bool ping) > spin_lock(&wdt->lock); > > writel_relaxed(UNLOCK, wdt->base + WDTLOCK); > - writel_relaxed(wdt->load_val, wdt->base + WDTLOAD); > + writel_relaxed(INT_MASK, wdt->base + WDTINTCLR); > > if (!ping) { > - writel_relaxed(INT_MASK, wdt->base + WDTINTCLR); > + writel_relaxed(wdt->load_val, wdt->base + WDTLOAD); > writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + > WDTCONTROL); > } > That would require additional changes. Reason is that the load value is not immediately written after a timeout change, but only with the next ping (which happens immediately afterwards). With your proposed change, the load value would never be updated. Besides, that would be a separate change, and would require a separate patch. Guenter
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