Re: 2.6.19 timer API changes

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Atsushi Nemoto wrote:

>>When I run the kernel it hangs in the calibrate_delay function. 
>>Eventually the complete kernel does run but it runs very slow. 
>>This is usually an issue with the Timer Interuppt setup etc.  But I have
>>looked at the other MIPS ports and seem to have made the same changes. 

>>On the PNX8550 it does not use the CP0 timer but use a different timer (the
>>Custom MIPS core has 3 extra timers) 

> Hmm, do the TIMER1 and CP0_COUNTER run at same speed?  If no, the
> PNX8550 port should be broken (i.e. gettimeofday() did not work
> properly) even without the timer API changes.  You should provide
> custom clocksource.mips_read (previously named mips_hpt_read) function
> which returns TIMER1 counter value.  If the TIMER1 was not 32-bit
> free-run counter, some trick would be required.  Refer sb1250 or
> jmr3927 for example.

    I would like to discourage you from repeating those JMR3927 clocksource 
"tricks" when you have 3 spare count/compare regs. This will warrant troubles 
when clockevents support gets merged into mainline (in fact, it was not 
necessary even on JMR3927 which has 3 timers). Although, if the timer isn't 
auto-reloading (I assume it isn't), the trick shouldn't be needed.

> ---
> Atsushi Nemoto

WBR, Sergei