From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from an-out-0708.google.com (an-out-0708.google.com [209.85.132.240]) by ozlabs.org (Postfix) with ESMTP id 8C9DBDE168 for ; Sat, 17 May 2008 00:26:50 +1000 (EST) Received: by an-out-0708.google.com with SMTP id c34so269027anc.78 for ; Fri, 16 May 2008 07:26:48 -0700 (PDT) Message-ID: Date: Fri, 16 May 2008 08:26:47 -0600 From: "Grant Likely" Sender: glikely@secretlab.ca To: mojtaba Subject: Re: Booting Linux from an ACE File In-Reply-To: <007a01c8b74c$0ad9c2e0$208d48a0$@com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: <007a01c8b74c$0ad9c2e0$208d48a0$@com> Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, May 16, 2008 at 5:57 AM, mojtaba wrote: > Dear all, > > Could you please explain what happens exactly when Linux is booting from a > compact flash? > > To my few knowledge, the Linux compressed image will be copied somewhere in > memory, will be uncompressed and the control will jump to the beginning > address of the Linux kernel. There are several methods to do this. Option 1 is to pass the kernel zImage.elf to genace so that it gets wrapped up into the ace file itself and is loaded into RAM by the SystemACE on FPGA initialization. However, this requires that your FPGA design gets RAM initialized before the SysACE starts squirting in the Linux image (which isn't always the case). This option is also slow. Option 2 is to use an small bootloader blob (I think Xilinx has a technote with something suitable) loaded into BRAM that reads the CF card and copies a Linux image (hint; build a simpleImage when using arch/powerpc) off the CF and into RAM. This method boots the system faster, but requires a little bit more work. Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.