[PATCH 2/2] at91sam9_wdt: Allow watchdog to reset device at early boot

[Jean-Christophe PLAGNIOL-VILLARD]

> On Feb 20, 2015, at 3:51 PM, Boris Brezillon <boris.brezillon at free-electrons.com> wrote:
> 
> Hi Jean-Christophe,
> 
> On Fri, 20 Feb 2015 15:48:22 +0800
> Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com> wrote:
> 
>> 
>>> On Feb 18, 2015, at 8:57 PM, Timo Kokkonen <timo.kokkonen at offcode.fi> wrote:
>>> 
>>> By default the driver will start a kernel timer which keeps on kicking
>>> the watchdog HW until user space has opened the watchdog
>>> device. Usually this is desirable as the watchdog HW is running by
>>> default and the user space may not have any watchdog daemon running at
>>> all.
>>> 
>>> However, on production systems it may be mandatory that also early
>>> crashes and lockups will lead to a watchdog reset, even if they happen
>>> before the user space has opened the watchdog device.
>>> 
>>> To resolve the issue, add a new device tree property
>>> "early-timeout-sec" which will let the kernel timer to ping the
>>> watchdog HW only as long as the specified timeout permits. The default
>>> is still to use kernel timer, but more strict behavior can be enabled
>>> via the device tree property.
>>> 
>>> Signed-off-by: Timo Kokkonen <timo.kokkonen at offcode.fi>
>>> ---
>>> Documentation/devicetree/bindings/watchdog/watchdog.txt | 7 +++++++
>>> drivers/watchdog/at91sam9_wdt.c                         | 9 ++++++++-
>> 
>> This should not be handled by the driver but the kernel in a generic way
> 
> Could you detail a bit more what you have in mind ?

move this timeout on the linux thread that keep alive the watchdog not in the driver

Best Regards,
J.
> 
> Best Regards,
> 
> Boris
> 
> -- 
> Boris Brezillon, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com
> 
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