From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] clocksource: tegra: enable arch_timer
Date: Wed, 03 Apr 2013 16:48:06 -0600 [thread overview]
Message-ID: <515CB1A6.6090308@wwwdotorg.org> (raw)
In-Reply-To: <515CA060.7030100@gmail.com>
On 04/03/2013 03:34 PM, Rob Herring wrote:
> On 04/03/2013 01:22 PM, Stephen Warren wrote:
>> On 04/03/2013 07:28 AM, Rob Herring wrote:
>>> On 04/03/2013 06:32 AM, Joseph Lo wrote:
>>>> Architected timer is the local timer for Cortex-A15. Adding the support
>>>> for Tegra.
>>>>
>>>> Cc: John Stultz <john.stultz@linaro•org>
>>>> Cc: Thomas Gleixner <tglx@linutronix•de>
>>>> Signed-off-by: Joseph Lo <josephl@nvidia•com>
>>>
>>> My patch series to add CLOCKSOURCE_OF_DECLARE support to arch timer and
>>> sched_clock enhancements will make this unnecessary:
>>>
>>> http://www.spinics.net/lists/arm-kernel/msg234597.html
>>>
>>> Testing would be appreciated.
>>
>> Joseph (or Rob), what's the benefit of this change; what works with it
>> and/or what breaks without it?
>
> I assume you mean Joseph's change.
Yes.
> Well, it enables local timers on A15.
> But mine will too for Tegra if you have the arch timer in the dtb.
Well, I meant what benefit would I see from enabling them, rather than
using the Tegra-specific timers as I believe is currently happening.
>> Rob, if I did apply this change, and you also apply that series of
>> yours, what is the result: compile-time breakage, run-time breakage,
>> just some redundant code that needs to be removed again?
>
> Compile-time breakage as the functions called here are being removed.
OK, I definitely won't apply Joseph's patch then.
Aside from that, I took the git branch you mentioned in the patch you
linked to above, merged it into my dev tree, updated my bootloader to
actually initialize the TSC correctly, and I see the following during
boot, so I guess that's enough for:
Tested-by: Stephen Warren <swarren@nvidia•com>
on your patches.
> [ 0.000000] sched_clock: 32 bits at 1000kHz, resolution 1000ns, wraps every 4294967ms
> [ 0.000000] Architected local timer running at 12.00MHz (virt).
> [ 0.000000] Switching to timer-based delay loop
> [ 117.431229] Calibrating delay loop (skipped), value calculated using timer frequency.. 24.00 BogoMIPS (lpj=120000)
> [ 117.987221] Switching to clocksource arch_sys_counter
next prev parent reply other threads:[~2013-04-03 22:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-03 11:32 [PATCH] clocksource: tegra: enable arch_timer Joseph Lo
2013-04-03 13:28 ` Rob Herring
2013-04-03 18:22 ` Stephen Warren
2013-04-03 21:34 ` Rob Herring
2013-04-03 22:48 ` Stephen Warren [this message]
2013-04-04 10:28 ` Joseph Lo
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=515CB1A6.6090308@wwwdotorg.org \
--to=swarren@wwwdotorg$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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