From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 0/2] Use architected timers for delay loop
Date: Fri, 22 Jun 2012 16:09:32 +0100 [thread overview]
Message-ID: <1340377774-17173-1-git-send-email-will.deacon@arm.com> (raw)
Hello,
This patch series reworks our delay loop implementation to allow the
busy-loop to be replaced with the physical counter included as part of
the architected timer on recent CPUs. The polling implementation is
still maintained to support cores without the timers and we use the same
maths and upper delay bound of 2ms.
Russell - I think my maths is correct, but why can't we increase the
precision by using a magic constant of 4398046U and a right
shift of 31?
As usual, all feedback is welcome,
Will
Will Deacon (2):
ARM: arch timer: implement read_current_timer and get_cycles
ARM: delay: allow timer-based delay implementation to be selected
arch/arm/include/asm/arch_timer.h | 1 +
arch/arm/include/asm/delay.h | 19 +++++++--
arch/arm/include/asm/timex.h | 10 +++--
arch/arm/kernel/arch_timer.c | 11 +++++
arch/arm/kernel/armksyms.c | 3 +-
arch/arm/lib/Makefile | 2 +-
arch/arm/lib/{delay.S => delay-loop.S} | 16 +++----
arch/arm/lib/delay.c | 66 ++++++++++++++++++++++++++++++++
arch/arm/mach-sa1100/sleep.S | 8 ++--
9 files changed, 112 insertions(+), 24 deletions(-)
rename arch/arm/lib/{delay.S => delay-loop.S} (85%)
create mode 100644 arch/arm/lib/delay.c
--
1.7.4.1
next reply other threads:[~2012-06-22 15:09 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-22 15:09 Will Deacon [this message]
2012-06-22 15:09 ` [PATCH 1/2] ARM: arch timer: implement read_current_timer and get_cycles Will Deacon
2012-06-25 21:39 ` Stephen Boyd
2012-06-26 10:37 ` Will Deacon
2012-06-26 17:44 ` Stephen Boyd
2012-06-22 15:09 ` [PATCH 2/2] ARM: delay: allow timer-based delay implementation to be selected Will Deacon
2012-06-25 21:39 ` Stephen Boyd
2012-06-26 10:49 ` Will Deacon
2012-06-26 15:54 ` Will Deacon
2012-06-26 16:00 ` Rob Herring
2012-06-26 16:28 ` Will Deacon
2012-06-27 2:07 ` Stephen Boyd
2012-06-27 9:41 ` Will Deacon
2012-06-22 22:26 ` [PATCH 0/2] Use architected timers for delay loop Russell King - ARM Linux
2012-06-25 10:03 ` Will Deacon
2012-06-25 21:38 ` Stephen Boyd
2012-06-26 10:35 ` Will Deacon
2012-06-26 17:42 ` Stephen Boyd
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=1340377774-17173-1-git-send-email-will.deacon@arm.com \
--to=will.deacon@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).