From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Roese <sr@denx.de>
Date: Tue, 8 Apr 2008 12:06:21 +0200
Subject: [U-Boot-Users] [PATCH] Make MPC83xx one step closer to full
	relocation.
In-Reply-To: <1207647084.5826.14.camel@gentoo-jocke.transmode.se>
References: <1206715285-10532-1-git-send-email-Joakim.Tjernlund@transmode.se>
	<200804081058.31982.sr@denx.de>
	<1207647084.5826.14.camel@gentoo-jocke.transmode.se>
Message-ID: <200804081206.21726.sr@denx.de>
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To: u-boot@lists.denx.de

On Tuesday 08 April 2008, Joakim Tjernlund wrote:
> > I'm afraid, but the "other ppc's" did break with this patch. At least 4xx
> > does. With your patch applied relocation to SDRAM does not work anymore.
> > Here's what I get:
> >
> > CFG_MONITOR_BASE=fffa0000
> > (ulong)&_start + EXC_OFF_SYS_RESET=fffa2200
> > EXC_OFF_SYS_RESET=100
> >
> > I haven't looked into it closer yet. Any idea on how to fix this?
> >
> > Thanks.
> >
> > Best regards,
> > Stefan
>
> Oops, didn't see that coming. Your _start symbol in ppc4xx/start.S isn't
> pointing to your real start of execution. Seems like _start_440 is your
> real start but I can't be sure.

No, unfortunately it's not. _start_440 is loaded into the last 4k of bootrom 
(via linker script), since 440 has a shadow TLB upon startup to only map 4k 
of address space. After looking at System.map it seems that _start_of_vectors 
seems to be the way to go for 4xx:

fffa0004 T version_string
fffa0100 t CritcalInput
fffa0100 T _start_of_vectors

But I don't want to introduce some #ifdef here. Perhaps it would be better to 
introduce a common (PPC) label that points to the beginning of the U-Boot 
image here.

BTW: I think this version:

	len = (ulong)&_end - ((ulong)&_start - EXC_OFF_SYS_RESET);

instead of:

	len = (ulong)&_end - (ulong)&_start + EXC_OFF_SYS_RESET;

is better. Makes the transition from CFG_MONITOR_BASE clearer, don't you think 
so?

> There are some strange code in there 
> that I don't understand.

Yes, it's quite complex because it supports all 4xx variants.

Best regards,
Stefan

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