From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21696 invoked by alias); 24 Oct 2014 09:13:38 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Received: (qmail 21678 invoked by uid 89); 24 Oct 2014 09:13:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_SORBS_WEB autolearn=no version=3.3.2 X-HELO: xm21.hostsila.net Received: from xm21.hostsila.net (HELO xm21.hostsila.net) (80.91.189.41) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Fri, 24 Oct 2014 09:13:36 +0000 Received: from [195.20.130.1] (port=11544 helo=[10.1.7.235]) by xm21.hostsila.net with esmtpsa (TLSv1:DHE-RSA-AES128-SHA:128) (Exim 4.82) (envelope-from ) id 1Xhaxi-000Yqz-7V; Fri, 24 Oct 2014 12:15:10 +0300 Message-ID: <544A183B.6090206@unicore.co.ua> Date: Fri, 24 Oct 2014 09:13:00 -0000 From: Oleg Uzenkov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Sergei Gavrikov CC: eCos Discussion References: <544618E5.90101@unicore.co.ua> <54479031.9080106@unicore.co.ua> <5447C1D0.3070906@unicore.co.ua> <544918B9.7000601@unicore.co.ua> <544A0349.9020702@unicore.co.ua> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Get-Message-Sender-Via: xm21.hostsila.net: authenticated_id: o.uzenkov@unicore.co.ua X-IsSubscribed: yes Subject: Re: [ECOS] small custom bootloader to start an app stored in flash X-SW-Source: 2014-10/txt/msg00047.txt.bz2 Thanks, I will give it a try with ROM builds. > On Fri, 24 Oct 2014, Oleg Uzenkov wrote: > >> Redboot is a great piece of software. It is just I found that when you >> enable some important features like FIS support, Redboot reserves >> extra space in RAM memory. >> The size of this reserved extra space in RAM equals to the size of the >> largest section size in Flash. In case of stm32f407 it is 128KB. >> Internal RAM is 128KB. As John Dallaway pointed out there is very >> little sense in using Redboot without enough of external RAM on >> stm32f4 devices. For example for Kinetis it is a different story, the >> flash sections are uniform and quite small. >> >> For small systems external RAM chip significantly adds up to the cost >> of a device. > > I understand John's point and agree with him. But, he told about using > debug infrastructure of RedBoot (debugging eCos applications in RAM). > But, RedBoot is *debug* and *bootstrap* environment for eCos. I pointed > on another side of RedBoot, *bootstrap*. You can quite run eCos [ROM] > builds from FIS. FIS support requires 128KB of ram on stm32. > Those [ROM] applications may utilize all RAM (128K + > 64K) on your target. On start ROM application just does overlay RedBoot > memory. You saw that yesterday with Rainer's approach (exec). If you > cannot manage run [ROM] applications with RedBoot command 'go', just > implement one new command for RedBoot, e.g. 'xip' (as RedBoot already > uses 'exec' name to run Linux kernel). As far as I understand, 'go' command should work in theory as it sets program counter (pc) to the address of Entry point (not sure about stack pointer). To make a jump we need to set stack pointer and program counter. And this can be implemented inside a new 'xip' command. > RedBoot will let you to use > FLASH I/O, load any images, use start scripts, etc., etc. Of course it > is my opinion only. > > Sergei -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss