Re: [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range

[Timur Tabi]

Timur Tabi wrote:
> > A 32-bit counter is absolutely fine. Letting it run with a 400MHz clock
> > (or was it 200 MHz ?) is the problem. A resolution of 2.5ns for a
> > watchdog
> > timer does not really make any sense.
>
> The 10 second limit is based on a 20MHz clock.

No, that's not true.  I misread the code.  I knew something was wrong, 
but it didn't click until just now.

The default timeout is 10 seconds.  The max timeout on a 20MHz system 
(which is what we're running) is over 200 seconds.

The problem is that Pratyush's system is running at a clock that's way 
too fast:

 [  131.187562] sbsa-gwdt sbsa-gwdt.0: Initialized with 40s timeout @ 
250000000 Hz, action=1.

250MHz is unreasonable.  Pratyush, why is your system counter so high? 
On our ARM64 system, it's set to 20MHz.

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