Table of Contents

Intel Edison

edison-setup_miniboard_1.jpg

By default the Edison board uses Yocto Linux which really doesn't interest me. I'm not into this Arduino stuff, I normally write direct in C and don't want to have some kind of pre-build Linux.

So,the best way would be to put Gentoo Linux on the Edison (which I'm also using for lots of ARM boards).

I keep things short here for now. The Edison has an integrated eMMC and it's not that easy to write/partition it. Normally I've a removable SD-Card which I attach to my PC, create the partitions, compile u-boot, write u-boot, format partitions, build Gentoo, put Gentoo on root, build Kernel and finally put Kernel on /boot and insert the SD-Card to the board.

Access to the integrated eMMC is possible via DFU which makes things difficult. Another way would be an boot-able SD-Card. Problem for me, my break-out-board ( Intel® Edison and Mini Breakout Kit) has no external MMC-Card and I don't want to solder anything at this point.

Then I found ubilinux where you can download some scripts and a prebuild Ubuntu-like image. The image (*.ext4) can be mounted via '-o loop' and that's where I started. The most important part is to keep your gentoo as small as possible. A good way is to put portage into a squashfs image and so I came up with a 800MB gentoo.

More or less I did these things:

  1. create a new directory for your Gentoo-root: 
    mkdir gentoo_root
  2. download and extract i686-stage3 
    #check http://distfiles.gentoo.org/releases/x86/autobuilds/ for latest filename
wget http://distfiles.gentoo.org/releases/x86/autobuilds/current-stage3-i686/stage3-i686-20150303.tar.bz2 
tar -vjxf *.tar.bz2 -C gentoo_root
  3. change make.conf 
    # These settings were set by the catalyst build script that automatically
# built this stage.
# Please consult /usr/share/portage/config/make.conf.example for a more
# detailed example.
CHOST="i686-pc-linux-gnu"
CFLAGS="-march=i686 -mtune=atom -O2 -fomit-frame-pointer -pipe"
CXXFLAGS="${CFLAGS}"

# WARNING: Changing your CHOST is not something that should be done lightly.
# Please consult http://www.gentoo.org/doc/en/change-chost.xml before changing.
CHOST="i686-pc-linux-gnu"
# These are the USE flags that were used in addition to what is provided by the
# profile used for building.
USE="-X -alsa -ipv6 -doc -debug -gdbm -gmp mmx wifi bindist -systemd -nls -berkdb"

FEATURES="buildpkg"
PYTHON_TARGETS="python2_7"
USE_PYTHON="2.7"

PORTDIR="/usr/portage"
DISTDIR="${PORTDIR}/distfiles"
  4. compile everything you need, also do 
    emerge --update --newuse --deep --with-bdeps=y @world
emerge --depclean
  5. prepare portage for squashfs (we'll use a compressed portage, which is only about 90MB: 
    #create links for writeable folders
rm -rf /usr/portage/distfiles
rm -rf /usr/portage/packages

ln -fs /mnt/root/usr/portage/packages /usr/portage/packages 
ln -fs /mnt/root/usr/portage/distfiles /usr/portage/distfiles 

#compress portage
mksquashfs /usr/portage/ portage.squash -noappend -e /usr/portage/packages/ -e /usr/portage/distfiles/

#remove portage
rm -rf /usr/portage*

#create rw-folders
mkdir /usr/portage/packages
mkdir /usr/portage/distfiles
  6. download ubilinux 
    wget http://www.emutexlabs.com/files/ubilinux/ubilinux_0.9_quark-live_usb_install.zip
unzip ubilinux_0.9_quark-live_usb_install.zip
  7. create copy for new gentoo image: 
    mkdir toFlash/ext4_img
cp -r toFlash toFlash_gentoo
  8. mount image files, we need the original to copy some files later on
    mount toFlash/edison-image-edison.ext4 toFlash/ext4_img -o loop

mount toFlash_gentoo/edison-image-edison.ext4 toFlash_gentoo/ext4_img -o loop
  9. update ext4-image content: 
    rsync -av --delete gentoo_root/ toFlash_gentoo/ext4_img/
  10. copy important stuff from old ext4-image to loop_mountpoint 
    cp toFlash/ext4_img/boot toFlash_gentoo/ext4_img/boot 
cp toFlash/ext4_img/lib/firmware toFlash_gentoo/ext4_img/lib/firmware 

cp toFlash/ext4_img/etc/modprobe.d/ toFlash_gentoo/ext4_img/etc/modprobe.d/

echo -e '#!/bin/sh\n\necho 1 >/sys/devices/virtual/misc/watchdog/disable\n" > toFlash_gentoo/ext4_img/etc/local.d/no_watchdog.start

echo -e 'chmod +x toFlash_gentoo/ext4_img/etc/local.d/no_watchdog.start' >> toFlash_gentoo/ext4_img/etc/local.d/no_watchdog.start

#set a password
passwd
  11. update modules 
    chroot toFlash_gentoo/ext4_img/
depmod -a
exit
  12. add agetty for serial interface (toFlash_gentoo/ext4_img/etc/inittab) 
    # SERIAL CONSOLES
#s0:12345:respawn:/sbin/agetty 38400 ttyS0 vt100
#s1:12345:respawn:/sbin/agetty 9600 ttyS1 vt100
s0:12345:respawn:/sbin/agetty 115200 ttyMFD2 vt100
  13. unmount image and check for errors 
    unmount toFlash/ext4_img
unmount toFlash_gentoo/ext4_img
e2fsck -f toFlash_gentoo/edison-image-edison.ext4
  14. flash gentoo (see ubilinux for details)
    cd toFlash_gentoo/
./flashall.sh

As an alternative you could simply use my ext4 image and replace the one from ubilinux. The flashing takes quite a while, about 1h for me.

Misc

For wifi you should probably create a config-file for the mac on the board: 

Eddi ~ # cat /config/wifi/mac.txt 
02:00:86:db:6e:54

For portage on the board, you've to do some mounts (requires kernel with squashfs support): 

mkdir /mnt/root
mount /dev/mmcblk0p8 /mnt/root
mount /portage.squash /usr/portage

Bigger root

Eddi ~ # parted /dev/mmcblk0
GNU Parted 3.2
Using /dev/mmcblk0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) 
unit
B
del 10
del 9
resize
8
3909074431
q

Eddi ~ # resize2fs /dev/mmcblk0p8
resize2fs 1.42.12 (29-Aug-2014)
Filesystem at /dev/mmcblk0p8 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mmcblk0p8 is now 937979 (4k) blocks long.

Eddi ~ # df
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root        3481284 765668   2533436  24% /
devtmpfs           10240      0     10240   0% /dev
tmpfs              98408    416     97992   1% /run
cgroup_root        10240      0     10240   0% /sys/fs/cgroup
shm               492024      0    492024   0% /dev/shm