Re: [ECOS] redboot startup mode

[Gary Thomas <gary at mlbassoc dot com>]

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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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