[gentoo-embedded] x86 SBC Gentoo Embedded HowTo version 0.04 (unfinished)

[Heath H Holcomb]

#---------------------------------------------------------------------------------------
# Embedded Gentoo How-To for x86
#
# Commands to setup a Gentoo embedded environment, you must be root.
# These commands are to be run on your developement system, 
# any x86 Gentoo Linux computer will do.  The system should be fast,
# to speed developement.  The target can be any x86 based SBC.  I'm
# using a Geode based SBC.  Latter I'll use a Via based SBC.
#
# version 0.04
# 2005.11.05
#
# Heath Holcomb (heath at bulah.com)
# Lloyd Sargent (contributor)
# Ned Ludd (embedded Gentoo project lead, original commands posted)
# Yuri Vasilevshi (contributor)
# Mike George (contributor)
# Kammi Cazze (contributor)
#
# development_rootfs = what you use to build the embedded_rootfs
# embedded_rootfs = rootfs you deploy to the target system
# SBC = single board computer (here it's an x86 based)
#
# References
# http://www.gentoo.org/doc/en/handbook/index.xml
# http://www.epiawiki.org
# http://epia.kalf.org
# Gentoo embedded mailing list (gentoo-embedded@l.g.o)
#
#
#---------------------------------------------------------------------------------------

# create the development_rootfs
# I use i586 becasue of target is a Geode processor
mkdir -p /opt/i586-gentoo-uclibc-linux/usr/portage

# download the latest stage 1 tarball
wget \ 
http://gentoo.osuosl.org/experimental/x86/embedded/stages/stage1-x86-uclibc-2005.0.tar.bz2

# untar the stage to the development_rootfs
tar -xvjf stage1-x86-uclibc-2005.0.tar.bz2 -C /opt/i586-gentoo-uclibc-linux/

# mount the development_rootfs proc and portage directories
# don't understand this someone please add comments
mount --bind /proc /opt/i586-gentoo-uclibc-linux/proc/
mount --bind /usr/portage /opt/i586-gentoo-uclibc-linux/usr/portage

# copy over DNS information to the development_rootfs
cp /etc/resolv.conf /opt/i586-gentoo-uclibc-linux/etc/resolv.conf

# chroot into the development_rootfs, create new environment, 
# load variables into memory
chroot /opt/i586-gentoo-uclibc-linux /bin/bash --login
env-update
source /etc/profile

# modify make.conf file to your liking
nano -w /etc/make.conf
# this is for my target, Geode x86 processor
USE="uclibc"
CHOST="i586-gentoo-linux-uclibc"
CFLAGS="-march=i586 -Os -pipe -fomit-frame-pointer -mmmx"
CXXFLAGS="${CFLAGS}"
FEATURES="buildpkg"

# start the bootstrip script
cd /usr/portage/scripts
./bootstrap.sh -p -v
./bootstrap.sh

# emerge system for the development rootfs
emerge -e system

# I'm bulding busybox and uclibc here, what you do may vary
# build busybox and uclibc, put into the embedded_rootfs (/embedded_rootfs)
# we emerge applications in our developement rootfs and then
# emerge -K into our embedded rootfs, that way we don't get the extra files
# created by the build/emerge process into our embedded rootfs which needs
# to be as small as possible
mkdir /embedded_rootfs
cd /usr/portage/sys-apps/baselayout-lite/
ROOT=/embedded_rootfs emerge baselayout-lite-1.0_pre1.ebuild
ROOT=/embedded_rootfs emerge -K uclibc
emerge busybox
ROOT=/embedded_rootfs emerge -K busybox 

# emerge other software you need for you embedded target
# this is very wildly depending on your needs
emerge foobar*
ROOT=/embedded_rootfs emerge -K foobar*

# install a kernel into embedded_rootfs, 2.6.11.5 for example
emerge vanilla-sources
cd /usr/src/
ln -s linux linux-2.6.11.5
cd linux
make menuconfig //configure your kernel for your TARGET SBC here
cp /usr/src/linux/arch/i386/bzImage /embedded_rootfs/boot/vmlinuz-2.6.11.5

# install a boot loader, grub for example
# once you copy/deploy your embedded rootfs program to you target SBC
# you will have to run the gurb on the command line to write to the master
# boot record (MBR)
emerge grub
ROOT=/embedded_rootfs emerge -K grub

# set time zone in your embedded_rootfs
# see http://leaf.sourceforge.net/doc/guide/buci-tz.html for details


......... more stuff here ...........
......... install xorg-x11, less than 10MB hopefully
......... install light window manager (blackbox, windowmaker, ???)
......... install very light X11 toolkit (?????)
......... purge to the embedded_rootfs of unwanted files and libaries
......... edit all config files
......... set up the test harddrive on the target SBC 
......... install grub or lilo on the test harddrive on the target SBC
......... transfer embedded_rootfs to the test harddrive on the target SBC 
......... debug system, and rebuild
......... deploy embedded_rootfs from the test harddrive to flash (DiskOnChip, 
Compact Flash)
......... tweak, rebuild, redeploy 



-- 
Heath Holcomb
heath@×××××.com
www.bulah.com
-- 
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