From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from xm.dlasys.net (unknown [24.152.213.223]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id D2917685C4 for ; Wed, 19 Oct 2005 05:36:26 +1000 (EST) Received: from [206.223.20.140] (port=2115 helo=[206.223.20.140]) by xm.dlasys.net with esmtp (Exim 4.52 #1 (Debian)) id 1ERwx3-0002IX-2k for ; Tue, 18 Oct 2005 15:16:45 -0400 Message-ID: <435549C2.1000106@dlasys.net> Date: Tue, 18 Oct 2005 15:15:14 -0400 From: "David H. Lynch Jr." MIME-Version: 1.0 To: linuxppc-embedded References: <4354AC78.5080206@comcast.net> <4354B707.6060002@iki.fi> In-Reply-To: <4354B707.6060002@iki.fi> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Subject: Re: Need help Understanding initial memory conditions. Reply-To: dhlii@comcast.net List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Kalle Pokki wrote: > David H. Lynch Jr wrote: > >> What exactly is the minimal startup system state the Linux 2.6.13 >> Kernel expects ? > > > It's pretty hard to describe the system state fully, as there are so > many registers it may depend on. However, I can point out a few things > from your setup: > > 1. Put RAM to 0x0000000 and flash to some location it mirrors to your > boot vector. Linux always expects your physical memory to be at zero. > It is then mapped to virtual address 0xC0000000. In both this list and elsewhere I have seen several references to the difficulty setting up Linux with a physical RAM base other than 0x0. I was hoping that I could bypass that by re-arranging physical memory using the BAT's or MMU. I am gathering that while this is possible, that it not sufficient. That if memory is re-arranged after power-on it has to be done by something Linux is not aware of. > > 2. You don't need to have MMU enabled. There is a god. I am a compitent developer with lots of low level experience, but I have thus far completely missed out on both PPC assembler and memory management. > > 3. Make sure your boot arguments are passed properly to the kernel. > This includes the settings in registers r3 ... r7 and the bd_info > structure . There are many variants of that structure, make sure you > use the same ones in the boot loader and in Linux. That I should have no problem with. > > Thank You very much