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From: Stefan Roese <sr@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] arch/powerpc/cpu/ppc4xx/start.S: comment makes little sense
Date: Tue, 23 Nov 2010 06:51:11 +0100	[thread overview]
Message-ID: <201011230651.11733.sr@denx.de> (raw)
In-Reply-To: <20101121191701.DFCF1678@gemini.denx.de>

Hi Wolfgang,

On Sunday 21 November 2010 20:17:01 Wolfgang Denk wrote:
> I think this comment in arch/powerpc/cpu/ppc4xx/start.S needs a bit of
> cleanup:
> 
>   51 /*  U-Boot - Startup Code for AMCC 4xx PowerPC based Embedded Boards
>   52  *
>   53  *
>   54  *  The processor starts at 0xfffffffc and the code is executed
>   55  *  from flash/rom.
>   56  *  in memory, but as long we don't jump around before relocating.
>   57  *  board_init lies at a quite high address and when the cpu has
>   58  *  jumped there, everything is ok.
>   59  *  This works because the cpu gives the FLASH (CS0) the whole
>   60  *  address space at startup, and board_init lies as a echo of
>   61  *  the flash somewhere up there in the memorymap.
>   62  *
>   63  *  board_init will change CS0 to be positioned at the correct
>   64  *  address and (s)dram will be positioned at address 0
>   65  */
> 
> All this makes pretty little sense to me.

Agreed. I'll try to get a better description out soon.

Cheers,
Stefan

--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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      reply	other threads:[~2010-11-23  5:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-21 19:17 [U-Boot] arch/powerpc/cpu/ppc4xx/start.S: comment makes little sense Wolfgang Denk
2010-11-23  5:51 ` Stefan Roese [this message]

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