From: Dave Martin <dave.martin@linaro.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org,
Tony Lindgren <tony@atomide.com>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
Jean Pihet <j-pihet@ti.com>,
linux-omap@vger.kernel.org,
Nicolas Pitre <nicolas.pitre@linaro.org>
Subject: Re: [PATCH v2] ARM: Define wfi() macro for v6 processors
Date: Tue, 8 Feb 2011 11:16:35 +0000 [thread overview]
Message-ID: <20110208111635.GA3333@arm.com> (raw)
In-Reply-To: <20110208110808.GA22877@n2100.arm.linux.org.uk>
On Tue, Feb 08, 2011 at 11:08:08AM +0000, Russell King - ARM Linux wrote:
> On Tue, Feb 08, 2011 at 11:01:25AM +0000, Dave Martin wrote:
> > For v6, wfi is architected as a defined MCR instruction, so
> > use that definition.
> >
> > Doing a no-op instead of wfi() is probably bad, so for older
> > processors than v6, wfi() is not defined. If needed, some CPU-
> > specific wfi() will have to be defined elsewhere.
>
> This is something we kind-of already handle in a different way - see
> the individual processor idle function in arch/arm/mm/proc*.S.
>
> There's various errata work-arounds older CPUs need for wfi (or rather
> its mcr equivalent) so maybe wfi() should just be an alias for a call
> to that function. Or maybe we shouldn't have a wfi() macro at all.
OK-- I'll hold off on this for now.
The patch was prompted by a build failure, but I can't remember the
exact circumstances now... if I hit the same problem again,
then it might be worth discussing further...
Cheers
---Dave
WARNING: multiple messages have this Message-ID (diff)
From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: Define wfi() macro for v6 processors
Date: Tue, 8 Feb 2011 11:16:35 +0000 [thread overview]
Message-ID: <20110208111635.GA3333@arm.com> (raw)
In-Reply-To: <20110208110808.GA22877@n2100.arm.linux.org.uk>
On Tue, Feb 08, 2011 at 11:08:08AM +0000, Russell King - ARM Linux wrote:
> On Tue, Feb 08, 2011 at 11:01:25AM +0000, Dave Martin wrote:
> > For v6, wfi is architected as a defined MCR instruction, so
> > use that definition.
> >
> > Doing a no-op instead of wfi() is probably bad, so for older
> > processors than v6, wfi() is not defined. If needed, some CPU-
> > specific wfi() will have to be defined elsewhere.
>
> This is something we kind-of already handle in a different way - see
> the individual processor idle function in arch/arm/mm/proc*.S.
>
> There's various errata work-arounds older CPUs need for wfi (or rather
> its mcr equivalent) so maybe wfi() should just be an alias for a call
> to that function. Or maybe we shouldn't have a wfi() macro at all.
OK-- I'll hold off on this for now.
The patch was prompted by a build failure, but I can't remember the
exact circumstances now... if I hit the same problem again,
then it might be worth discussing further...
Cheers
---Dave
next prev parent reply other threads:[~2011-02-08 11:16 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-08 11:01 [PATCH v2] ARM: Define wfi() macro for v6 processors Dave Martin
2011-02-08 11:01 ` Dave Martin
2011-02-08 11:08 ` Russell King - ARM Linux
2011-02-08 11:08 ` Russell King - ARM Linux
2011-02-08 11:16 ` Dave Martin [this message]
2011-02-08 11:16 ` Dave Martin
2011-02-08 12:11 ` Arnd Bergmann
2011-02-08 12:11 ` Arnd Bergmann
2011-02-08 12:13 ` Russell King - ARM Linux
2011-02-08 12:13 ` Russell King - ARM Linux
2011-02-08 12:53 ` Arnd Bergmann
2011-02-08 12:53 ` Arnd Bergmann
2011-02-08 14:45 ` Dave Martin
2011-02-08 14:45 ` Dave Martin
2011-02-08 14:54 ` Santosh Shilimkar
2011-02-08 14:54 ` Santosh Shilimkar
2011-02-08 15:09 ` Dave Martin
2011-02-08 15:09 ` Dave Martin
2011-02-08 15:17 ` Arnd Bergmann
2011-02-08 15:17 ` Arnd Bergmann
2011-02-08 16:32 ` Russell King - ARM Linux
2011-02-08 16:32 ` Russell King - ARM Linux
2011-02-08 16:58 ` Arnd Bergmann
2011-02-08 16:58 ` Arnd Bergmann
2011-02-08 17:15 ` Dave Martin
2011-02-08 17:15 ` Dave Martin
2011-02-08 15:15 ` Arnd Bergmann
2011-02-08 15:15 ` Arnd Bergmann
2011-02-08 15:30 ` Dave Martin
2011-02-08 15:30 ` Dave Martin
2011-02-08 15:42 ` Arnd Bergmann
2011-02-08 15:42 ` Arnd Bergmann
2011-02-08 16:21 ` Dave Martin
2011-02-08 16:21 ` Dave Martin
2011-02-09 10:07 ` Arnd Bergmann
2011-02-09 10:07 ` Arnd Bergmann
2011-02-08 16:25 ` Russell King - ARM Linux
2011-02-08 16:25 ` Russell King - ARM Linux
2011-02-08 16:31 ` Dave Martin
2011-02-08 16:31 ` Dave Martin
2011-02-08 16:47 ` Arnd Bergmann
2011-02-08 16:47 ` Arnd Bergmann
2011-02-08 16:55 ` Russell King - ARM Linux
2011-02-08 16:55 ` Russell King - ARM Linux
2011-02-08 17:00 ` Dave Martin
2011-02-08 17:00 ` Dave Martin
2011-02-08 16:20 ` Russell King - ARM Linux
2011-02-08 16:20 ` Russell King - ARM Linux
2011-02-08 16:28 ` Dave Martin
2011-02-08 16:28 ` Dave Martin
2011-02-08 12:22 ` Dave Martin
2011-02-08 12:22 ` Dave Martin
2011-02-08 12:31 ` Santosh Shilimkar
2011-02-08 12:31 ` Santosh Shilimkar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110208111635.GA3333@arm.com \
--to=dave.martin@linaro.org \
--cc=j-pihet@ti.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=nicolas.pitre@linaro.org \
--cc=santosh.shilimkar@ti.com \
--cc=tony@atomide.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.