RE: [PATCH v4] ARM: perf: save/restore pmu registers in pm notifier

-----Original Message-----
From: Will Deacon [mailto:will.deacon@arm.com]
Sent: 2014年7月4日 1:57
To: Neil Zhang
Cc: Sudeep Holla; 'linux@arm.linux.org.uk'; 'linux-arm-
kernel@lists.infradead.org'; 'linux-kernel@vger.kernel.org';
'devicetree@vger.kernel.org'
Subject: Re: [PATCH v4] ARM: perf: save/restore pmu registers in pm
notifier

On Mon, Jun 30, 2014 at 11:39:15AM +0100, Neil Zhang wrote:

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I will prepare another patch to add DT description under PMU
since there is no generic power domain support for pm notifier
if no other

concerns.

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We can change the manner if there is generic power domain
support for

pm notifier later.

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Thanks.

No, please don't add any DT bindings for power domains specific

to

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PMU node.
We can't change the DT bindings once added.

As I pointed out the DT bindings for generic power domains are
under discussion.
See if you can reuse it, if not help in extending it so that it

can be used.

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Sorry for reply later.
As I said before the under discussed generic power domain is not
suitable for CPU peripherals since they are all known belong to CPU
or cluster power domain.
If we want to follow the way they are discussion, we need to
register core and cluster power provider, and need vfp/gic/pmu etc

to require them.

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Is it really suitable?

Do you have any comments?
If no, I would like to put it under PMU node.

Sudeep is a better person to comment than me, but I'd still rather this
was handled more generically as opposed to a PMU-specific hack. I don't
see a problem including GIC and VFP here, but only when we actually
need to save/restore them (i.e. what the hardware guys went crazy with
the power domains).

Long time no follow up for this loop.
Sorry that I will pick it again.

Will,
I prefer to check always-on field under PMU node to check whether we need
Save/restore them.

Here is a sample for arch timer which also add under itself.
What do you think?

commit 82a5619410d4c4df65c04272db198eca5a867c18
Author: Lorenzo Pieralisi [off-list ref]
Date:   Tue Apr 8 10:04:32 2014 +0100

    clocksource: arch_arm_timer: Fix age-old arch timer C3STOP detection issue

Will

Best Regards,
Neil Zhang