[PATCH] ppc44x/watchdog: Select WATCHDOG_NOWAYOUT option

[Kumar Gala]

On Jul 13, 2012, at 7:25 AM, Josh Boyer wrote:

> On Fri, Jul 13, 2012 at 7:50 AM, Kumar Gala <galak at kernel.crashing.org> wrote:
>> 
>> On Jul 12, 2012, at 9:44 PM, Jiang Lu wrote:
>> 
>>> On PPC44x core, the WRC(Watchdog-timer Reset Control) field of TCR
>>> of timer can not reset by software after set to a non-zero value.
>>> Which means software can not reset the timeout behaviour of watchdog timer.
>>> 
>>> This patch selects WATCHDOG_NOWAYOUT option for 44x platforms to
>>> indicate the watchdog timer can not be disabled once fired.
>>> 
>>> Signed-off-by: Jiang Lu <lu.jiang at windriver.com>
>>> ---
>>> drivers/watchdog/Kconfig |    1 +
>>> 1 files changed, 1 insertions(+), 0 deletions(-)
>> 
>> I believe this is not 44x specific, but how Book-E watchdog is architected.
> 
> That is my understanding as well.
> 
>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>> index 3709624..41f3dff 100644
>>> --- a/drivers/watchdog/Kconfig
>>> +++ b/drivers/watchdog/Kconfig
>>> @@ -1084,6 +1084,7 @@ config PIKA_WDT
>>> config BOOKE_WDT
>>>      tristate "PowerPC Book-E Watchdog Timer"
>>>      depends on BOOKE || 4xx
>>> +     select WATCHDOG_NOWAYOUT if 44x
>> 
>> This should probably be 'select WATCHDOG_NOWAYOUT if BOOKE'
> 
> I kind of disagree with this change.  It's a user selectable option for
> a reason.
> 
> Right now, if the option is not set we call booke_wdt_disable which
> indeed does not actually _disable_ the WDT, but it does set the timer
> period to the maxium value.  We could go one step further and implement
> a simple timer that pops and calls booke_wdt_ping if WATCHDOG_NOWAYOUT
> is not set, then rearms itself.  That would leave the user with the
> ability to perform recovery of the userspace process that exited or
> died and was responsible for pinging the watchdog.
> 
> josh

My only care was about it being Book-E and not 44x.  Otherwise I'm happy to defer to your take on this.

- k