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Groups > linux.kernel > #1311950 > unrolled thread

[PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset

Started bySandeep Tripathy <tripathy@broadcom.com>
First post2016-01-19 07:10 +0100
Last post2016-01-19 08:20 +0100
Articles 4 — 3 participants

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  [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset Sandeep Tripathy <tripathy@broadcom.com> - 2016-01-19 07:10 +0100
    Re: [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-19 08:00 +0100
      Re: [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-19 08:20 +0100
      Re: [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset Guenter Roeck <linux@roeck-us.net> - 2016-01-19 08:20 +0100

#1311950 — [PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset

FromSandeep Tripathy <tripathy@broadcom.com>
Date2016-01-19 07:10 +0100
Subject[PATCH 1/1] watchdog: sp805: ping fails to abort wdt reset
Message-ID<qSxEl-3Dv-3@gated-at.bofh.it>
 sp805 wdt asserts interrupt for the first expiry and
reloads the counter. If wdt interrupt is set and count
reaches zero then wdt reset event is generated.To get
wdt reset at t timeout the driver loads wdt counter
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.

Signed-off-by: Sandeep Tripathy <tripathy@broadcom.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);
 
-- 
1.7.9.5

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#1311960

FromViresh Kumar <viresh.kumar@linaro.org>
Date2016-01-19 08:00 +0100
Message-ID<qSyqJ-41m-1@gated-at.bofh.it>
In reply to#1311950
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@broadcom.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);
        }


Please try if this works or not.

-- 
viresh

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#1311970

FromViresh Kumar <viresh.kumar@linaro.org>
Date2016-01-19 08:20 +0100
Message-ID<qSyK5-4tL-13@gated-at.bofh.it>
In reply to#1311960
On 18-01-16, 23:11, Guenter Roeck wrote:
> 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@broadcom.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.

Hmm, maybe then we can keep the original patch as is :)

@Sandeep: Please resend your patch after fixing the commit log and not
the diff.

-- 
viresh

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#1311972

FromGuenter Roeck <linux@roeck-us.net>
Date2016-01-19 08:20 +0100
Message-ID<qSyK5-4tL-15@gated-at.bofh.it>
In reply to#1311960
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@broadcom.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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