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

On Thu, 2015-08-06 at 12:20 +0800, Chenhui Zhao wrote:

On Thu, Aug 6, 2015 at 10:57 AM, Scott Wood [off-list ref] 
wrote:

quoted

On Wed, 2015-08-05 at 18:11 +0800, Chenhui Zhao wrote:

quoted

 On Tue, Aug 4, 2015 at 4:26 AM, Scott Wood [off-list ref]
 wrote:
 > On Mon, 2015-08-03 at 19:32 +0800, Chenhui Zhao wrote:
 > >  >
 >
 > >  On Sat, Aug 1, 2015 at 7:59 AM, Scott Wood 
[off-list ref]
 > >  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.

What interrupt could actually happen to a sleeping cpu that this protects 
against?

-Scott