From: Chenhui Zhao <chenhui.zhao@freescale•com>
To: Scott Wood <scottwood@freescale•com>
Cc: <b29983@freescale•com>, <b07421@freescale•com>,
<linux-kernel@vger•kernel.org>,
Tang Yuantian <Yuantian.Tang@freescale•com>,
"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>
Subject: Re: [PATCH 1/3] Powerpc: mpc85xx: refactor the PM operations
Date: Thu, 6 Aug 2015 13:54:26 +0800 [thread overview]
Message-ID: <1438840466.23384.2@remotesmtp.freescale.net> (raw)
In-Reply-To: <1438839985.2097.151.camel@freescale.com>
On Thu, Aug 6, 2015 at 1:46 PM, Scott Wood <scottwood@freescale•com>
wrote:
> On Thu, 2015-08-06 at 12:20 +0800, Chenhui Zhao wrote:
>> On Thu, Aug 6, 2015 at 10:57 AM, Scott Wood
>> <scottwood@freescale•com>
>> 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@freescale•com>
>> > > 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@freescale•com>
>> > > > > 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
Not sure. Maybe spurious interrupts or hardware exceptions. However,
setting them make sure dead cpus can not be waked up unexpectedly.
-Chenhui
next prev parent reply other threads:[~2015-08-06 5:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1438334444-31919-1-git-send-email-b29983@freescale.com>
[not found] ` <1438334444-31919-2-git-send-email-b29983@freescale.com>
[not found] ` <1438388082.19345.85.camel@freescale.com>
[not found] ` <1438602724.7515.3@remotesmtp.freescale.net>
2015-08-03 21:18 ` [PATCH 2/3] PowerPC/mpc85xx: Add hotplug support on E5500 and E500MC cores Scott Wood
2015-08-05 10:39 ` Chenhui Zhao
[not found] ` <1438387178.19345.77.camel@freescale.com>
[not found] ` <1438601578.7515.2@remotesmtp.freescale.net>
[not found] ` <1438633568.2097.35.camel@freescale.com>
[not found] ` <1438769477.21522.0@remotesmtp.freescale.net>
[not found] ` <1438829848.2097.129.camel@freescale.com>
2015-08-06 4:20 ` [PATCH 1/3] Powerpc: mpc85xx: refactor the PM operations Chenhui Zhao
2015-08-06 5:46 ` Scott Wood
2015-08-06 5:54 ` Chenhui Zhao [this message]
2015-08-06 18:02 ` Scott Wood
2015-08-07 3:19 ` Chenhui Zhao
2015-08-08 0:13 ` Scott Wood
[not found] ` <1438334444-31919-3-git-send-email-b29983@freescale.com>
[not found] ` <1438388531.19345.88.camel@freescale.com>
[not found] ` <1438772906.21522.2@remotesmtp.freescale.net>
[not found] ` <1438831004.2097.146.camel@freescale.com>
2015-08-06 4:32 ` [PATCH 3/3] PowerPC/mpc85xx: Add hotplug support on E6500 cores Chenhui Zhao
2015-08-06 5:44 ` Scott Wood
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