Re: [RFC PATCH 1/5] arm:omap1/2/3/4:Convert 32k-Sync clocksource driver to platform_driver

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Wed, Jan 18, 2012 at 01:34:55PM +0000, Hiremath, Vaibhav wrote:
> On Wed, Jan 18, 2012 at 17:29:52, Russell King - ARM Linux wrote:
> > On Wed, Jan 18, 2012 at 04:58:02PM +0530, Vaibhav Hiremath wrote:
> > > Convert counter_32k clocksource driver to standard platform_driver
> > > and move it drivers/clocksource/ directory.
> > > 
> > > Also, rename it to more generic name "omap-32k.c".
> > 
> > NAK.  sched_clock is supposed to be available early.  Platform device
> > driver initialization is FAR too late.
> > 
> Russell,
> 
> Sched_clock is available very early during boot sequence. Initially gp-timer 
> (dmtimer) will get registered as a clocksource. Please refer to the file
> mach-omap2/timer.c
> 
> 32k_sync timer (omap-32k.c) will come get registered during arch_init.
> 
> Just FYI, the way I tested it is, I used kernel parameter 
> "clocksourse=counter-32k", the switch from gp-timer to 32k timer
> will happen once it gets registered.

So please delete the sched_clock code from the 32k timer stuff you've
moved to a platform driver.  It will cause sched_clock to reset to zero,
and that's bad news.

Only one sched_clock() should ever be registered, and that should only be
registered very early at boot time.