Subject: [PATCH V2] [ARM] Add ARCH_PROVIDES_UDELAY config option

From: [email-masked] (Saravana Kannan)
Date: Mon, 21 Jun 2010 18:14:10 -0700

Russel,

Would appreciate your thoughts on this.

Colin,

Are you continuing to use the approach used in your patch in your 
development tree? I just want to make sure we have a solution that 
everyone can agree to.

Thanks,
Saravana

Saravana Kannan wrote:
> Russell King - ARM Linux wrote:
>> My point is not specific to sched_clock, but to counters which on ARM
>> are 99.9% always memory mapped, and therefore inaccessible during the
>> very early kernel boot.  sched_clock was merely an illustration of the
>> problem.
> 
> Do you know any code which uses udelay that early? I can't imagine any 
> non-driver code using udelay. If it's just drivers using udelay, then 
> they need IO mapping to have been completed for the device register 
> access to work and hence udelay won't have any problems.
> 
> -Saravana
>