Hi Heath,
I know about the limited number of write cycles on CF. Therefore I want
the CF only to supply the kernel and the ramdisk image. My intention is
to run Linux and my application completely from ramdisk.
I want my device to be complately silent, therefore it has a fanless
ME6000 board, no fans in the case and no harddisk (actually strange to
'hear' a computer boot in complete silence!). The CF is on an IDE
converter and is recognized as /dev/hda1 (although for testing it has a
normal harddisk connected).
I was able to follow your howto to the end.
Although I had some problems where the boot process stopped after
"Freeing unused kernel memory". This turned out to be a typo in
/etc/fstab on my side.
Now that I have bootable configuration, I can look into what it
takes to
have the system files in a ramdisk image and have it mounted as '/'.
I think I could just create an initrd from the whole system and have
grub and the kernel extract it in memory and mount it.
I have not done much investigation on it, be it seems to me that the
/linuxrc in the initrd can be fairly simple. Actually just calling the
/sbin/init once the ramdisk is mountded as '/'.
Anyone any experience with this?
PS. Maybe we should spawn of another thread about VIA Epia boards, CF
and booting. I saw Pierre Cassimans is interested in this subject as
well.
This might go off topic for the Gentoo Embedded Howto.
Marcel
-----Original Message-----
From: Heath Holcomb [mailto:[EMAIL PROTECTED] Sent: Sunday, 14
August, 2005 0:53
To: [email protected]
Subject: Re: [gentoo-embedded] x86 SBC Gentoo Embedded HotTo version
0.07
On Friday 12 August 2005 01:39 am, Marcel Romijn wrote:
Hello Heath,
Nice writedown! I haven't made it to the end yet (lack of time), but
I'm
getting there...
I noticed some issues along the way (not counting grub begin spelled
as
"grug" or "gurb" ;-) )
In step 3 you write:
<snip>
# Set root password for the embedded_rootfs
chromm /embedded_rootfs
passwd
rm /embedded_rootfs/etc/passwd-
Exit
</snip>
I presume 'chromm' should have been 'chroot' ?
If it is indeed 'chroot' then you should either do "rm /etc/passwd-"
before the "exit" or the "exit" before the "rm
/embedded_rootfs/etc/passwd-".
Yes, "chromm" should be "chroot". The order is correct, as far as I
can
tell.
chroot /embedded_rootfs
passwd
rm /embedded_rootfs/etc/passwd-
exit
A few lines down, you write:
<snip>
rm -R /embedded_rootfs/var/db/pkg/ *
</snip>
As a reletive newbie, doing a quick copy/paste of this command late in
the evening as root in '/', this wiped out all files, except the ones
that were firmly locked.
Fortunately, I'm going through you HowTo in VMWare, so I could restore
a
previous snapshot ;-)
I presume the space before the '*' should have been omitted?
<snip>
rm -R /embedded_rootfs/var/db/pkg/*
</snip>
Major typo on my part. Fixed in version 0.08.
My aim is to create an embedded Gentoo for a Via Epia ME6000, which
reads the kernel and a ramdisk image from CF and then runs completely
from RAM.
If I'm not mistaken, you were heading for a Via Epia as well?
My target will be a Via based SBC. From what I have read using a
ramdisk on a x86 based platform really does not buy you much. But
you sure don't
want to write to the CF all that often (limited write cycles,
usallay 100,000 to
300,000). So I plan on mounting the / partition of the CF as read only
and creating a separate partition that is mounted read/write and
have my
embedded application and only my application write to that partition.
Regards,
Marcel Romijn
-----Original Message-----
From: Heath Holcomb [mailto:[EMAIL PROTECTED]
Sent: Monday, 08 August, 2005 4:17
To: [email protected]
Subject: [gentoo-embedded] x86 SBC Gentoo Embedded HotTo version 0.07
Version 0.07
Please add, delete, modify. Thanks!
Several fixes. Root password now works. Several work arounds are no
longer
need, as the embedded Gentoo team has fixed them (I'm guess because I
no
longer get those errors). There is still one problem when "emerge -e
system"
for groff. Bug 98187 (http://bugs.gentoo.org/show_bug.cgi?id=98187).
Check
out the bug report for the temp fix/work around (USE="-sandbox" emerge
-e
system).
I've update my website with this version also.
http://www.bulah.com/embeddedgentoo.html
#-----------------------------------------------------------------------
---------
# Embedded Gentoo How-To for x86
#
# A how-to guide to setup a Gentoo embedded environment, you must be
root.
# These commands are to be run on your development system,
# any x86 Gentoo Linux computer will do. The system should be fast,
# to speed development. The target can be any x86 based SBC. I'm
# using a Geode based SBC. Latter I'll use a Via based SBC.
#
# version 0.07
# 2005.8.7
#
# Heath Holcomb (heath at bulah.com)
# Ned Ludd (original commands posted)
# Lloyd Sargent (contributor)
# Yuri Vasilevski (contributor)
# Mike George (contributor)
# Kammi Cazze (contributor)
# Marius Schaefer (contributor)
#
# Definitions and Terms
# system_rootfs = your regular rootfs, development computer
# 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 ([email protected])
#
#
# Overview of process (steps)
# 1 - Prepare the development_rootfs from your system_rootfs
# 2 - Build the development_rootfs
# 3 - Build the embedded_rootfs
# 4 - Build and install non-system programs to the embedded_rootfs
# 5 - Build and install a kernel to the embedded_rootfs
# 6 - Deploy embedded_rootfs to target
#
#-----------------------------------------------------------------------
---------
#----- Step 1 - Prepare the development_rootfs from your system_rootfs
-------
# You must be root.
su -
# Create the development_rootfs.
# I use i586 because 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-ucl
ibc-2005.0.tar.bz2
# Untar the stage to the development_rootfs.
tar -xvjpf stage1-x86-uclibc-2005.0.tar.bz2 -C
/opt/i586-gentoo-uclibc-linux/
# Mount the proc and portage directories to your development_rootfs.
# Makes your system_rootfs's proc and portage directory available from
inside
# of your development_rootfs (after chrooting).
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.
chroot /opt/i586-gentoo-uclibc-linux /bin/bash --login
#----- Step 2 - Build the development_rootfs
---------------------------------
# Create new environment and load variables into memory.
env-update
source /etc/profile
# Modify make.conf file to your liking/needs.
nano -w /etc/make.conf
# This is for my target, Geode x86 processor.
/*
USE="bitmap-fonts minimal truetype-fonts mmx"
CHOST="i586-gentoo-linux-uclibc"
CFLAGS="-march=i586 -Os -pipe -fomit-frame-pointer -mmmx"
CXXFLAGS="${CFLAGS}"
FEATURES="buildpkg"
VIDEO_CARDS="chips"
UCLIBC_CPU="586MMX"
*/
# Set profile to use 2.6 kernel.
# The current stage uses 2.4 by default, and for most cases you are
going
# to want a 2.6.x kernel.
cd /etc/
unlink make.profile
ln -s ../usr/portage/profiles/uclibc/x86 make.profile
# Start the bootstrap script.
cd /usr/portage/scripts
./bootstrap.sh -p -v
./bootstrap.sh
# Emerge the system ebuild for the development_rootfs.
emerge -e system
#----- Step 3 - Build the embedded_rootfs
------------------------------------
# Create the embedded_rootfs directory.
mkdir /embedded_rootfs
# Emerge baselayout-lite into embedded_rootfs.
# This gives your system a basic file structure.
# 1.0_pre1 is the only one that is stable, right?
cd /usr/portage/sys-apps/baselayout-lite/
ROOT=/embedded_rootfs emerge baselayout-lite-1.0_pre1.ebuild
# Workaround 1
# Baselayout-lite is still beta, so a few fixes are needed.
# There needs to be a directory "log" in /var.
# Inittab calls for /usr/bin/tail, but it needs to /usr/bin.
mkdir /embedded_rootfs/var/log
nano -w /embedded_rootfs/etc/inittab
/*
#tty3::respawn:/usr/bin/tail -f /var/log/messages
tty3::respawn:/bin/tail -f /var/log/messages
*/
# Emerge uclibc into the embedded_rootfs.
# Use the -K option because 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.
ROOT=/embedded_rootfs emerge -K uclibc
# Emerge busybox into the embedded_rootfs.
# First you must emerge it into your development_rootfs.
# This does not create the symlinks in our development embedded
rootfs.
emerge busybox
ROOT=/embedded_rootfs emerge -K busybox
# Create the symlinks for busybox in the embedded_rootfs.
mkdir /embedded_rootfs/proc
mount -o bind /proc/ /embedded_rootfs/proc/
chroot /embedded_rootfs /bin/busybox --install -s
umount /embedded_rootfs/proc
# Set time zone in your embedded_rootfs.
# See http://leaf.sourceforge.net/doc/guide/buci-tz.html for details.
# For central standard time in the US, use "CST6CDT".
nano -w /embedded_rootfs/etc/TZ
/*
CST6CDT
*/
# Install a boot loader (usually grug or lilo).
# Once you copy/deploy your embedded_rootfs to your target SBC you
will
# have to run grub on the command line to write to the master boot
record
# (MBR).
# For some reason not all of /boot/grub is copied over to the
# embedded_rootfs, so a extra manual copy step is needed.
# The --nodeps gets rip of the run time need of ncurses.
emerge --nodeps grub
ROOT=/embedded_rootfs emerge -K --nodeps grub
cp -R /boot/grub /embedded_rootfs/boot/
# Modify your boot configure file.
# The example below is for a gurb, for a boot partition on /dev/hda1
and
only
# one partition on the target SBC system.
nano -w /embedded_rootfs/boot/grub/grub.conf
/*
default 0
timeout 10
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
title=Linux 2.6.x
root (hd0,0)
kernel /vmlinuz-2.6.x root=/dev/hda1 vga=792
*/
# Set root password for the embedded_rootfs
chromm /embedded_rootfs
passwd
rm /embedded_rootfs/etc/passwd-
exit
# Modify fstab.
# Below is mine, yours may vary.
nano -w /embedded_rootfs/etc/fstab
/*
/dev/hda1 / reiserfs defaults
0 0
none /proc proc defaults
0 0
none /sys sysfs defaults
0 0
none /dev/shm tmpfs defaults 0 0
*/
# Clean up the embedded_rootfs.
# Don't know why these files are there in the first place, so if
anyone
# can tell me why.....
rm -R /embedded_rootfs/var/db/pkg/ *
rm -R /embedded_rootfs/var/lib/portage/
#---- Step 4 - Build and install non-system programs to the
embedded_rootfs --
# Emerge other software you need for you embedded target.
# This is very wildly depending on your needs.
# Also your proprietary application will be done here.
emerge foo*
ROOT=/embedded_rootfs emerge -K foo*
#---- Step 5 - Build and install a kernel to the embedded_rootfs
-------------
# Install a kernel into embedded_rootfs.
# First we will emerge it into our development_rootfs, then configure
and
# build it.
emerge vanilla-sources
cd /usr/src/
cd linux
make menuconfig
# Configure your kernel for your TARGET SBC here. I HIGHLY suggest
you
# configure the kernel to compile everything into the kernel, and
nothing
# as a module.
make
ROOT=/embedded_rootfs make modules_install
cp /usr/src/linux/arch/i386/boot/bzImage
/embedded_rootfs/boot/vmlinuz-2.6.x
# A few notes on compiling your kernel.
# If deploying to Compact Flash/DiskOnChip/SD use ext2, as the
journaling
# filing systems "write" to much for a flash device.
# If deploying to a hard drive use a journaling filing system, such as
# ext3 or reiserfs.
#---- Step 6 - Deploy embedded_rootfs to target
------------------------------
# Prepare a Gentoo (or any Linux distro) system on the target SBC
using
a
# harddrive. This is known as the target development rootfs.
# We will create a partition (/embedded_rootfs) that will server as
our
# "test" partition to deploy our embedded_rootfs that we generate on
our
# development_system.
#
# I use the following partitions to speed development (yours may
vary):
# /dev/hda1 - /embedded_rootfs - 1 GB
# /dev/hda2 - /boot - 100 MB
# /dev/hda3 - swap - (size varies, 512 MB is a good number)
# /dev/hda4 - / - (what is left, at least 1.5 GB per 2005.0 install
guide
specs)
#
# Copy over your embedded_rootfs from you development system to your
target
# system and the directory /embedded_rootfs. This needs to be done
via
NFS as
# need to preserve the permissions.
#
#The following commands are done from the
# target development rootfs.
mount -t reiserfs /dev/hda1 /mnt/embedded_rootfs
mount -t nfs\
192.168.0.10:/opt/i586-gentoo-uclibc-linux/embedded_rootfs\
/mnt/nfs_embedded_rootfs
cp -adpR /mnt/nfs_embedded_rootfs/* /mnt/embedded_rootfs
# Modify your target system's gurb.conf (or lilo.conf) for allow you
to
boot
# to the embedded_rootfs partition.
#
# Reboot, and if all goes well you'll be greeted with a login prompt.
#
# Fin.
--
heath holcomb
liquidcable at bulah.com
www.bulah.com
--
[email protected] mailing list
