From: Kamel BOUHARA <k.bouhara@gmail.com>
To: barebox@lists.infradead.org
Subject: Re: iMX27 clock settings
Date: Wed, 15 Feb 2012 10:15:05 +0100 [thread overview]
Message-ID: <CAM9uW_4Df7yazcWNvai0ffALC1eHrMUC5WetMNf=KJ7PBhm51w@mail.gmail.com> (raw)
In-Reply-To: <CALQ+5adUP4qyf8+82s2NK6R3LbvjteuE-bkQ0iUdMG7X2LtxFQ@mail.gmail.com>
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Hi Igor,
What revision of imx27 silicon do you have?
If it's a rev2.0 or 2.1, you shoult take a look a the freescale errata in
order to set your PLL properly.
Regards.
2012/2/14 Igor Trevisan <igt1972@gmail.com>
> Hi,
>
> I'm working on a custom board based on iMX27L. Initially I worked with
> Redboot
> as Linux bootloader but now, I'm happily working with Barebox (2012.01.0)
> having replaced Redboot with it.
>
> Everithing is fine (thanks to the guys in the list for helping me!) but...
> I noticed that my Linux apps run more slowly within my system if it's
> started by Barebox
> then if it's started by Redbbot.
> I think it's a matter of internal clocks settings.
>
> I see that Redboot, for example, set:
> CSR=0x33F38107
> while Barebox does:
> writel(0x33F30307 | CSCR_MPLL_RESTART | CSCR_SPLL_RESTART, CSCR)
> That brings to CSR=0x33F30307 at the end of the PLLs restart procedure.
>
> Reading the Manual I can see that the differences between the two settings
> mean having an arm_clk that is 2/3 and an AHB_clk that's the half.
>
> Is there a particular reason for having these "slower configuration"?
>
> I tried to change the lowlevel_init.S to force 0x33F38107 into CSCR
> at startup but, after that change, my board starts, has time to write
> somenthing on the
> serial console:
>
> "barebox 2012.01.0-svn11070-dirty1 (Feb 14 2012 - 11:10:39)
>
> Board: Freescale iÿ"
>
> and then restarts... continuously.
>
> Can anybody help me to understand this and to make (if possible) my
> system faster?
> Thanks in advance,
> Igor
>
>
> --
> "Don't find fault, find a remedy."
> (Henry Ford)
>
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
>
--
_______________________________
*Kamel BOUHARA*
62 Bis Rue Carnot
60610 Lacroix Saint-Ouen
Tel n°1: +33634677323
n°2: +33617832904
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next prev parent reply other threads:[~2012-02-15 9:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-14 15:10 Igor Trevisan
2012-02-15 9:15 ` Kamel BOUHARA [this message]
2012-02-15 11:10 ` Igor Trevisan
2012-02-15 9:29 ` Juergen Beisert
2012-02-15 12:09 ` Sascha Hauer
2012-02-15 14:59 ` Igor Trevisan
2012-02-15 16:06 ` Igor Trevisan
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