Re: [PATCH 1/3] Powerpc: mpc85xx: refactor the PM operations

[Chenhui Zhao]

On Thu, Aug 6, 2015 at 10:57 AM, Scott Wood <scottwood@xxxxxxxxxxxxx> 
wrote:
> On Wed, 2015-08-05 at 18:11 +0800, Chenhui Zhao wrote:
> >  On Tue, Aug 4, 2015 at 4:26 AM, Scott Wood <scottwood@xxxxxxxxxxxxx>
> >  wrote:
> >  > On Mon, 2015-08-03 at 19:32 +0800, Chenhui Zhao wrote:
> >  > >  >
> >  >
> >  > >  On Sat, Aug 1, 2015 at 7:59 AM, Scott Wood 
> > <scottwood@xxxxxxxxxxxxx>
> >  > >  wrote:
> >  >
> >  > >  >
> >  > >  > Could you explain irq_mask()?  Why would there still be IRQs
> >  > > destined
> >  > >  > for
> >  > >  > this CPU at this point?
> >  > >
> >  > >  This function just masks irq by setting the registers in RCPM 
> > (for
> >  > >  example, RCPM_CPMIMR, RCPM_CPMCIMR). Actually, all irqs to 
> > this CPU
> >  > >  have been migrated to other CPUs.
> >  >
> >  > So why do we need to set those bits in RCPM?  Is it just caution?
> >
> >  Setting these bits can mask interrupts signalled to RCPM from MPIC 
> > as a
> >  means of
> >  waking up from a lower power state. So, cores will not be waked up
> >  unexpectedly.
>
> Why would the MPIC be signalling those interrupts if they've been 
> masked at
> the MPIC?
>
> -Scott

The interrupts to RCPM from MPIC are IRQ, Machine Check, NMI and 
Critical interrupts. Some of them didn't be masked in MPIC.

-Chenhui

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