This is the mail archive of the
ecos-discuss@sources.redhat.com
mailing list for the eCos project.
Re: how does processor finds redboot image ?
- From: Sumit Chauhan <sumitchauhan79 at gmail dot com>
- To: Sumit Chauhan <sumitchauhan79 at gmail dot com>, ecos-discuss at sources dot redhat dot com
- Date: Thu, 17 Mar 2005 06:14:36 -0500
- Subject: Re: [ECOS] how does processor finds redboot image ?
- References: <aa5610790503170226136a1976@mail.gmail.com> <20050317110541.GC26260@lunn.ch>
- Reply-to: Sumit Chauhan <sumitchauhan79 at gmail dot com>
Hi,
thanks for your reply, I understand most of it -;)
I didnt knew basically that by default ARM maps flash at 0x00000000 ,
anyways, but / so if my redboot is in ROM mode .. redboot_ROM.ecm was
used, will it keep on executing from flash only ? is this remapping
done only for ROMRAM, RAM modes I believe,as else we would have been
able to write the flash anyways -:)
Sumit
On Thu, 17 Mar 2005 12:05:41 +0100, Andrew Lunn <andrew@lunn.ch> wrote:
> On Thu, Mar 17, 2005 at 05:26:16AM -0500, Sumit Chauhan wrote:
> > Hi,
> >
> > I have a very basic question and hopefully will answer this,
> > when a processor reset happens, say as in case of IXP425 it starts pc
> > at 0x00000000 , Then how does it starts loading redboot from flash ??
> > or does as in my case redboot image is a ROM based, it just shifts it
> > execution to flash start sector and XIP ?
>
> I don't know about this specific processor, but in general the ARM
> maps the FLASH to address 0x0 at startup. eCos ROM startup mode then
> arranges to have the FLASH remapped to higher memory and then eCos
> jumps to the higher memory copy of itself. It then puts RAM at address
> 0x0.
>
> Andrew
>
--
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss