Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver

[Sergei Shtylyov]

Hello.

Kumar Gala wrote:

> > Index: linux-2.6/arch/powerpc/kernel/time.c
> > ===================================================================
> > --- linux-2.6.orig/arch/powerpc/kernel/time.c
> > +++ linux-2.6/arch/powerpc/kernel/time.c
[...]
> > @@ -128,6 +129,83 @@ unsigned long ppc_tb_freq;
> >  static u64 tb_last_jiffy __cacheline_aligned_in_smp;
> >  static DEFINE_PER_CPU(u64, last_jiffy);
> >
> > +#ifdef CONFIG_GENERIC_CLOCKEVENTS
> > +
> > +#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
> > +#define DECREMENTER_MAX 0xffffffff
> > +#else
> > +#define DECREMENTER_MAX 0x7fffffff /* setting MSB triggers an  
> > interrupt */
> > +#endif
> > +
> > +static int decrementer_set_next_event(unsigned long evt,
> > +                      struct clock_event_device *dev)
> > +{
> > +#if defined(CONFIG_40x)
> > +    mtspr(SPRN_PIT, evt);    /* 40x has a hidden PIT auto-reload  
> > register */
> > +#elif defined(CONFIG_BOOKE)
> > +    mtspr(SPRN_DECAR, evt); /* Book E has  separate auto-reload  
> > register */
> > +    set_dec(evt);

> what's the point of setting decar if you're just going to set_dec as  well?

   Bothered to read the Book E specs? ;-)
   Loading DECAR doesn't auto-reload DEC. What I want is both set the 
auto-reload value and start counting down from it at the same time (if the 
decrementer is in auto-reload mode).

[big cut-off]

WBR, Sergei
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