From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11572 invoked by alias); 24 May 2005 16:50:01 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Received: (qmail 11449 invoked by uid 22791); 24 May 2005 16:49:44 -0000 Received: from sta-206-168-96-204.rockynet.com (HELO hermes.chez-thomas.org) (206.168.96.204) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Tue, 24 May 2005 16:49:44 +0000 Received: by hermes.chez-thomas.org (Postfix, from userid 2000) id 3E851100060; Tue, 24 May 2005 10:49:42 -0600 (MDT) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by hermes.chez-thomas.org (Postfix) with ESMTP id 00DFC10000C; Tue, 24 May 2005 10:49:36 -0600 (MDT) From: Gary Thomas To: yrodguez@iuma.ulpgc.es Cc: eCos Discussion In-Reply-To: <20050524174110.zvo62etf4skoccg4@webmail.iuma.ulpgc.es> References: <20050524174110.zvo62etf4skoccg4@webmail.iuma.ulpgc.es> Content-Type: text/plain Date: Tue, 24 May 2005 22:27:00 -0000 Message-Id: <1116953376.19176.45.camel@hermes> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [ECOS] redboot startup mode X-SW-Source: 2005-05/txt/msg00320.txt.bz2 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 ------------------------------------------------------------ -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss