From: Gary Thomas <gary@mlbassoc.com>
To: yrodguez@iuma.ulpgc.es
Cc: eCos Discussion <ecos-discuss@ecos.sourceware.org>
Subject: Re: [ECOS] redboot startup mode
Date: Wed, 25 May 2005 02:37:00 -0000 [thread overview]
Message-ID: <1116954112.19176.49.camel@hermes> (raw)
In-Reply-To: <20050524175806.gj72jy7dy8kw0ck4@webmail.iuma.ulpgc.es>
Please reply to the eCos mailing list so that all may benefit. Private
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On Tue, 2005-05-24 at 17:58 +0100, yrodguez@iuma.ulpgc.es wrote:
> But, who exactly have to copy redboot code from flash to ram?, I'm
Look in the platform startup code:
<ecos>/packages/arm/arm9/excalibur/current/include/hal_platform_setup.h
> sorry, maybe
> i don't understand it due to my bad level in english
>
> thanks.
>
> Quoting Gary Thomas <gary@mlbassoc.com>:
>
> > On Tue, 2005-05-24 at 17:41 +0100, yrodguez@iuma.ulpgc.es wrote:
> >> hi,
> >> i have a doubt/question?
> >>
> >> i'm trying to compile a redboot in romram mode.
> >>
> >>
> >> At http://sources.redhat.com/ecos/docs-latest/redboot/excaliburarm9.html
> >>
> >> say that romram mode runs redboot from ram with redboot in flash. I supossed
> >> that redboot is stored in flash memory and then it is copied from
> >> flash to ram.
> >> But when i desassemble the file i get the code is mapped on ram (0x8000):
> >>
> >
> > Correct. It has to be that way - the linker produces an image suitable
> > for running from RAM. That said, the image will be stored in FLASH
> > (typically this is all that's accessible immediately after RESET). The
> > program [RedBoot or whatever] then does some minimal hardware
> > initialization, e.g. turning on the SDRAM controller, setting up mapping
> > registers, etc. The code is then copied from FLASH to its ultimate RAM
> > destination and control is then passed there. Now you are running from
> > RAM only. It's up to the startup code to understand all of this and
> > it must contain [normally position-independent] code that performs these
> > steps at startup.
> >
> > Note: this mode is only suitable for *the* initial "ROM" monitor code,
> > like RedBoot. This is not how you would write a generic program which
> > runs in RAM but whose image was stored in FLASH. For that, you use
> > RedBoot's FIS commands (create, load)
> >
> > --
> > ------------------------------------------------------------
> > Gary Thomas | Consulting for the
> > MLB Associates | Embedded world
> > ------------------------------------------------------------
> >
> >
>
>
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
--
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next prev parent reply other threads:[~2005-05-24 17:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-24 18:26 yrodguez
2005-05-24 22:27 ` Gary Thomas
[not found] ` <20050524175806.gj72jy7dy8kw0ck4@webmail.iuma.ulpgc.es>
2005-05-25 2:37 ` Gary Thomas [this message]
2005-05-25 6:57 ` yrodguez
2005-05-25 7:50 ` [ECOS] Clean room module loader + GPL module + Application C.J.
2005-05-26 12:30 ` Bart Veer
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