linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: daniel.lezcano@linaro.org (Daniel Lezcano)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] clocksource: arm_global_timer: Allow DT to specify already reset timer counter
Date: Wed, 16 Dec 2015 07:59:34 +0100	[thread overview]
Message-ID: <56710BD6.2090502@linaro.org> (raw)
In-Reply-To: <CABb+yY0_JvVV_HG_iU8KJjmwu-nq_Cu5hJ6HBoKZCrZAdJ=rLQ@mail.gmail.com>

On 12/16/2015 05:11 AM, Jassi Brar wrote:
> On Tue, Dec 15, 2015 at 11:32 PM, Daniel Lezcano
> <daniel.lezcano@linaro.org> wrote:
>> On 11/25/2015 06:24 AM, Jassi Brar wrote:
>>>
>>> The GT counter is common to every core in a cluster. There is a usecase
>>> when Linux is spawned by a 'master' firmware/OS running on some core of
>>> the same cluster and the GT is used by the both.
>>>    Linux, upon boot, resetting the GT counter is obviously fatal to the
>>> other OS. So provide a way for DT to tell Linux if it's running in that
>>> 'slave' mode and must not reset the counter.
>>>
>>> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
>>
>>
>> Hmm, I doubt that is a hardware description.
>>
> Its a regular 2core-1cluster platform. The master RTOS on cpu0
> maintains the lifecycle of Linux on cpu1.
>
> 'No_Counter_Reset' is not a h/w thing, I agree, but I don't know how
> to better convey that platform specific constraint.

May be with a kernel parameter ?

-- 
  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

  reply	other threads:[~2015-12-16  6:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-25  5:24 [PATCH] clocksource: arm_global_timer: Allow DT to specify already reset timer counter Jassi Brar
2015-12-15 18:02 ` Daniel Lezcano
2015-12-16  4:11   ` Jassi Brar
2015-12-16  6:59     ` Daniel Lezcano [this message]
2015-12-17  9:37       ` Jassi Brar
2015-12-17 10:08         ` Marc Zyngier
2015-12-17 10:29           ` Jassi Brar
2015-12-17 10:16         ` Daniel Lezcano
2015-12-17 10:24           ` Jassi Brar
2015-12-17 11:02           ` Mark Rutland
2015-12-15 18:14 ` Mark Rutland
2015-12-16  4:17   ` Jassi Brar

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=56710BD6.2090502@linaro.org \
    --to=daniel.lezcano@linaro.org \
    --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).