From: Scott Wood <scottwood@freescale•com>
To: Zhao Chenhui <chenhui.zhao@freescale•com>
Cc: linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH 1/7] powerpc/85xx: re-enable timebase sync disabled by KEXEC patch
Date: Fri, 4 Nov 2011 12:33:49 -0500 [thread overview]
Message-ID: <4EB421FD.6010805@freescale.com> (raw)
In-Reply-To: <1320409787-14360-1-git-send-email-chenhui.zhao@freescale.com>
On 11/04/2011 07:29 AM, Zhao Chenhui wrote:
> From: Li Yang <leoli@freescale•com>
>
> The timebase sync is not only necessary when using KEXEC. It should also
> be used by normal boot up and cpu hotplug. Remove the ifdef added by
> the KEXEC patch.
The KEXEC patch didn't just add the ifdef, it also added the initializers:
> @@ -105,8 +107,64 @@ smp_85xx_setup_cpu(int cpu_nr)
>
> struct smp_ops_t smp_85xx_ops = {
> .kick_cpu = smp_85xx_kick_cpu,
> +#ifdef CONFIG_KEXEC
> + .give_timebase = smp_generic_give_timebase,
> + .take_timebase = smp_generic_take_timebase,
> +#endif
> };
U-Boot synchronizes the timebase on 85xx. With what chip and U-Boot
version are you seeing this not happen?
If you are seeing only a small (around one tick) difference, make sure
you're running a U-Boot that has this commit:
> commit 7afc45ad7d9493208d89072cbb78a5bfc8034b59
> Author: Kumar Gala <galak@kernel•crashing.org>
> Date: Sun Mar 13 10:55:53 2011 -0500
>
> powerpc/85xx: Fix synchronization of timebase on MP boot
>
> There is a small ordering issue in the master core in that we need to
> make sure the disabling of the timebase in the SoC is visible before we
> set the value to 0. We can simply just read back the value to
> synchronizatize the write, before we set TB to 0.
>
> Reported-by: Dan Hettena
> Tested-by: Dan Hettena
> Signed-off-by: Kumar Gala <galak@kernel•crashing.org>
-Scott
next prev parent reply other threads:[~2011-11-04 17:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-04 12:29 [PATCH 1/7] powerpc/85xx: re-enable timebase sync disabled by KEXEC patch Zhao Chenhui
2011-11-04 17:33 ` Scott Wood [this message]
2011-11-04 19:33 ` Kumar Gala
2011-11-04 19:38 ` Scott Wood
2011-11-08 9:06 ` Li Yang-R58472
2011-11-08 17:28 ` Scott Wood
-- strict thread matches above, loose matches on Subject: below --
2010-12-03 12:34 Li Yang
2010-12-03 16:40 ` Kumar Gala
2010-12-03 18:27 ` Li Yang
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