From: Sascha Hauer <s.hauer@pengutronix.de>
To: Juergen Beisert <jbe@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] phyCORE-i.MX27: Keep frequency multiplier enabled to be able to do a warmstart
Date: Thu, 25 Aug 2011 12:02:27 +0200 [thread overview]
Message-ID: <20110825100227.GA4128@pengutronix.de> (raw)
In-Reply-To: <201011251752.42159.jbe@pengutronix.de>
On Thu, Nov 25, 2010 at 05:52:42PM +0100, Juergen Beisert wrote:
> commit 7d25a0552dd3a4b65412ae1cbf8f9ca8a88b5d27
> Author: Juergen Beisert <jbe@pengutronix.de>
> Date: Thu Nov 25 17:49:11 2010 +0100
>
> Keep frequency multiplier enabled to be able to do a warmstart
>
> The wachtdog's reset does only reset the ARM core, not the whole silicon.
> But the PLLs seems to do some strange things: It seems they switch back to
> the low frequency reference when the watchdog barks. But in the case the
> frequency multiplier is off (not used due to 26 MHz reference usage) the
> machine stops, because the PLLs are stopping due to the lack of a reference
> frequency. As the power on reset will set the FPM_EN bit again, a power cycle
> brings the machine back to life.
> By keeping the frequency multiplier enabled, also a warmstart triggered by the
> watchdog can restart the machine now.
>
> Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Applied to master. Maintainer was asleep for a long long time.
Sascha
>
> diff --git a/arch/arm/boards/pcm038/pll.h b/arch/arm/boards/pcm038/pll.h
> index 13a7989..15b94cf 100644
> --- a/arch/arm/boards/pcm038/pll.h
> +++ b/arch/arm/boards/pcm038/pll.h
> @@ -36,6 +36,7 @@
> CSCR_MCU_SEL | /* 26 MHz reference */ \
> CSCR_ARM_DIV(0) | /* CPU runs at MPLL/3 clock */ \
> CSCR_AHB_DIV(1) | /* AHB runs at MPLL/6 clock */ \
> + CSCR_FPM_EN | \
> CSCR_SPEN | \
> CSCR_MPEN)
>
> @@ -51,6 +52,7 @@
> CSCR_ARM_SRC_MPLL | /* use main MPLL clock */ \
> CSCR_ARM_DIV(0) | /* CPU run at full MPLL clock */ \
> CSCR_AHB_DIV(1) | /* AHB runs at MPLL/6 clock */ \
> + CSCR_FPM_EN | /* do not disable it! */ \
> CSCR_SPEN | \
> CSCR_MPEN)
>
>
> --
> Pengutronix e.K. | Juergen Beisert |
> Linux Solutions for Science and Industry | Phone: +49-8766-939 228 |
> Vertretung Sued/Muenchen, Germany | Fax: +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de/ |
>
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prev parent reply other threads:[~2011-08-25 10:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-25 16:52 Juergen Beisert
2011-05-25 12:39 ` Teresa Gamez
2011-08-25 10:02 ` Sascha Hauer [this message]
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