Open Firmware

Introduction

In 2006 the company of Open Firmware inventor Mitch Bradley, Firmworks, Inc, released their Open Firmware implementation under a BSD license. This code shares some code with SUN's OpenBOOT implementation. It supports the x86 architecture and runs, amongst others, as a LinuxBIOS payload. It is the firmware implementation on the OLPC.

Download

The code can be browsed online with the ViewVC facility.

The repository is available through Subversion:

You can check it out as follows:

 $ svn co svn://openbios.org/openfirmware/

if you want a specific revision:

 $ svn co svn://openbios.org/openfirmware -r 35

If your company installed a firewall that blocks the svn port (3690) you can also check out using the webdav frontend:

$ svn co https://www.openbios.org/openfirmware-svn/ openfirmware

LinuxBIOS

You should change openfirmware/cpu/x86/pc/biosload/config.fth:

Index: config.fth
===================================================================
--- config.fth  (revision 533)
+++ config.fth  (working copy)
@@ -9,7 +9,7 @@
 \ - Image Format - Example Media - previous stage bootloader
 
 \ - (Syslinux) COM32 format - USB Key w/ FAT FS - Syslinux
-create syslinux-loaded
+\ create syslinux-loaded
 
 \ - Linux kernel format - USB Key w/ FAT FS - LinuxBIOS w/ stripped Linux  payload 
 \ create bzimage-loaded
@@ -19,7 +19,7 @@
 \ create etherboot-variant  \ Enable additional tweaks for Etherboot
 
 \ - ELF format (no pheader) - ROM - LinuxBIOS direct
-\ create linuxbios-loaded
+create linuxbios-loaded
 
 \ Load and run in qemu
-\ create qemu-loaded 
+create qemu-loaded 

Building

Software Requirements:

   qemu-0.9.0 + ROMSIZE-patch
   Open Firmware rev. >= 500
   LinuxBIOS >= v2

Patch and build qemu

Get the patch from http://www.freimann.org/qemu_biossize.patch and apply it against qemu-0.9.0.

       tar xvfz qemu-0.9.0.tar.gz
       cd qemu-0.9.0
       wget http://www.freimann.org/qemu_biossize.patch
       patch -p1 < qemu_biossize.patch

Make sure that you have gcc-3.x installed, then

       ./config && make && make install

Build Open Firmware

Get Open Firmware from Subversion

       svn co svn://openbios.org/openfirmware

Change to the build directory of the biosload build.

       cd cpu/x86/pc/biosload/

To change the config file of Open Firmware you can either use the above patch, or you can edit config.fth with your favorite editor (vi!!1!). Uncomment the lines

       create linuxbios-loaded
       create qemu-loaded

Comment out the line with

       create syslinux-loaded

Now change to the build directory and type "make"

       cd build
       make

After make is finished there should be a file "ofwlb.elf" in the same directory. Copy this to your LinuxBIOSv[x] directory.

Build LinuxBIOS

Follow the instructions in the LinuxBIOS documentation. Make sure that you use the ofwlb.elf file as your payload. It is also very imortant that the ROMSIZE for LinuxBIOS and qemu correspond with each other.

Run it

   qemu  -L LinuxBIOSv3/build -hda path/to/disk.img -serial `tty` -nographic