Re: [PATCH V2 0/6] arm_smp_twd: mpcore_wdt: Fix MPCORE watchdog setup

Russell King - ARM Linux
2011-07-06T11:16:49Z

On Wed, Jul 06, 2011 at 12:05:48PM +0100, Catalin Marinas wrote:
> On Wed, Jul 06, 2011 at 11:14:56AM +0100, Russell King - ARM Linux wrote:
> > Do we know why the calibration was initially introduced? FWIR, it came
> > from the SMP group in ARM, so I guess they had a reason for it rather
> > than copying x86.
>
> I think it was introduced because the TWD frequency is half of the CPU
> frequency but the latter may not be known - boot monitor configuration
> could change it.

Okay, that implies we can't have a fixed frequency built into the kernel
then. For such platforms like the ARM dev boards (realview + vexpress),
I expect we can read the CPU frequency from somewhere like one of the
ICST PLLs.