Re: [PATCH] MIPS: Don't overflow cevt-r4k.c calculations at high clock rates.

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

On Tue, 18 May 2010, David Daney wrote:

> The 'mult' element of struct clock_event_device must never be wider
> than 32-bits.  If it were, it would get truncated when used by
> clockevent_delta2ns() when this calls do_div().
> 
> We meet the requirement by ensuring that the relationship:
> 
>  (mips_hpt_frequency >> (32 - shift)) < NSEC_PER_SEC
> 
> Always holds.

clocks_calc_mult_shift() is your friend :)

Thanks,

	tglx