From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [GIT PULL] Renesas ARM Based SoC Init Delay Updates For v3.18
Date: Fri, 05 Sep 2014 15:27:18 +0000 [thread overview]
Message-ID: <201409051727.18845.arnd@arndb.de> (raw)
In-Reply-To: <cover.1408927601.git.horms+renesas@verge.net.au>
On Monday 25 August 2014, Simon Horman wrote:
> Hi Olof, Hi Kevin, Hi Arnd,
>
> Please consider these Renesas ARM based SoC init delay updates for v3.18.
>
While looking at your branches, I noticed that you go to great lengths
to compute the correct lpj value and avoid the calibration.
However, I believe the "modern" way to do this is to call
register_current_timer_delay() in order to base the delay loop
on the hardware timer instead of looping in the CPU. This is
more accurate and more robust against CPU frequency scaling.
I'm applying the patches now, but it's something you may want
to look at in the future. On a related topic, your clocksource
drivers could be simplified for the DT-only case by using
CLOCKSOURCE_OF_DECLARE() instead of early_platform_init(), but
I don't know what the impact would be for the arch/sh and legacy
mach-shmobile cases.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [GIT PULL] Renesas ARM Based SoC Init Delay Updates For v3.18
Date: Fri, 5 Sep 2014 17:27:18 +0200 [thread overview]
Message-ID: <201409051727.18845.arnd@arndb.de> (raw)
In-Reply-To: <cover.1408927601.git.horms+renesas@verge.net.au>
On Monday 25 August 2014, Simon Horman wrote:
> Hi Olof, Hi Kevin, Hi Arnd,
>
> Please consider these Renesas ARM based SoC init delay updates for v3.18.
>
While looking at your branches, I noticed that you go to great lengths
to compute the correct lpj value and avoid the calibration.
However, I believe the "modern" way to do this is to call
register_current_timer_delay() in order to base the delay loop
on the hardware timer instead of looping in the CPU. This is
more accurate and more robust against CPU frequency scaling.
I'm applying the patches now, but it's something you may want
to look at in the future. On a related topic, your clocksource
drivers could be simplified for the DT-only case by using
CLOCKSOURCE_OF_DECLARE() instead of early_platform_init(), but
I don't know what the impact would be for the arch/sh and legacy
mach-shmobile cases.
Arnd
next prev parent reply other threads:[~2014-09-05 15:27 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-25 1:10 [GIT PULL] Renesas ARM Based SoC Init Delay Updates For v3.18 Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 01/10] ARM: shmobile: sh7372: Update DTS to include CPU frequency Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 02/10] ARM: shmobile: sh73a0: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 03/10] ARM: shmobile: r8a7778: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 04/10] ARM: shmobile: sh7372: Use shmobile_init_delay() Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 05/10] ARM: shmobile: r8a73a4: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 06/10] ARM: shmobile: Remove shmobile_setup_delay() Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 07/10] ARM: shmobile: sh73a0: Use shmobile_init_delay() Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 08/10] ARM: shmobile: r8a7778: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 09/10] ARM: shmobile: bockw: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-08-25 1:10 ` [PATCH 10/10] ARM: shmobile: kzm9g: " Simon Horman
2014-08-25 1:10 ` Simon Horman
2014-09-05 15:27 ` Arnd Bergmann [this message]
2014-09-05 15:27 ` [GIT PULL] Renesas ARM Based SoC Init Delay Updates For v3.18 Arnd Bergmann
2014-09-09 2:02 ` Simon Horman
2014-09-09 2:02 ` Simon Horman
2014-09-09 8:50 ` Arnd Bergmann
2014-09-09 8:50 ` Arnd Bergmann
2014-09-05 16:13 ` Arnd Bergmann
2014-09-05 16:13 ` Arnd Bergmann
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=201409051727.18845.arnd@arndb.de \
--to=arnd@arndb.de \
--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 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.