A Flashable Image for the Intel Edison

The Intel Edison system-on-a-chip boards are pretty cool, a little compute module can plug into a number of different breakout boards. There's an Arduino-style board, and another form-factor featuring a bunch of stackable modules (GPIO, SD Card, OLED Screen etc.) Since the system is a dual-core Atom, we can easily put CentOS on it! To start with we will focus on the userland components and use the kernel that comes bundled in the Edison toolkit.

If you'd rather not read the whole thing, here are some links to a flashable rootfs image and a yum repo containing the tools that go with it:
Bootable Image: http://people.centos.org/bstinson/edison/edison-image-centos.ext4.xz
Sources and Yum Repo: http://people.centos.org/bstinson/edison/7/

More of the upcoming work (building a kernel, and the rest of the SDK) will be done under the Alternate Architectures SIG once that is in full-swing. In the meantime I'd love to see discussion, bug reports, and collaboration on the centos-devel list.

My Email: brian (at) bstinson (dot) com

IRC: bstinson

Building your own rootfs image

If you'd like to spin your own image (instead of using the prebuilt image above) here are the steps you need to get a flashable image. The Edisons are fairly simple to install to (since the rootfs is simply an ext4 image)

To begin with we need a 1G file that will serve as our ext4 image

# Make a 1G file full of Zeros
root@host# dd if=/dev/zero of=~/projects/edison/edison-image-centos.ext4 bs=1M count=1024

# Put an ext4 filesystem on it
root@host# mkfs.ext4 ~/projects/edison/edison-image-centos.ext4

# Mount it someplace handy
root@host# mount -t ext4 ~/projects/edison/edison-image-centos.ext4 /mnt/edison-image-centos

Now that we have the image mounted in a useful place we can start installing
packages

# Add the centos-release and centos-release-edison files
root@host# rpm --root /mnt/edison-image-centos -Uvh --nodeps http://buildlogs.centos.org/centos/7/os/i386/Packages/centos-release-7-1.1503.el7.centos.2.8.1.i686.rpm\
http://people.centos.org/bstinson/edison/7/i386/Packages/centos-release-edison-1-1.el7.centos.noarch.rpm

# Tweak the basearch variable (allows you to do target install from an x86_64 host)
root@host# echo 'i386' > /mnt/edison-image-centos/etc/yum/vars/basearch

# Install the packages
root@host# yum --installroot=/mnt/edison-image-centos install bind-utils bash yum vim-minimal shadow-utils less iputils iproute firewalld rootfiles centos-release edison-modules edison-tweaks wpa_supplicant dhclient

Flashing the rootfs image

You can grab dfu-util for CentOS 7 from here

Connect the OTG port on the Edison breakout board to a USB port and it should show up as a dfu device.

# The dfu VendorID:ProductID is 8087:0a99 for the Edison
root@host# dfu-util -l -d 8087:0a99
dfu-util 0.8

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2014 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to dfu-util@lists.gnumonks.org

Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=11, name="initrd", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=10, name="vmlinuz", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=9, name="home", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=8, name="update", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=7, name="rootfs", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=6, name="boot", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=5, name="u-boot-env1", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=4, name="u-boot1", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=3, name="u-boot-env0", serial="UNKNOWN"
Found DFU: [8087:0a99] ver=9999, devnum=68, cfg=1, intf=0, alt=2, name="u-boot0", serial="UNKNOWN"

# Flash the image
root@host# dfu-util -d 8087:0a99 -a rootfs -D ~/projects/edison/edison-image-centos.ext4

Connect to the newly installed Edison

Plug the Console port into a USB port and fire up your favorite serial terminal
emulator

root@host# screen /dev/ttyUSB0 115200
Flashing already done...
GADGET DRIVER: usb_dnl_dfu
reading vmlinuz
5383904 bytes read in 133 ms (38.6 MiB/s)
Valid Boot Flag
Setup Size = 0x00003c00
Magic signature found
Using boot protocol version 2.0c
Linux kernel version 3.10.17-poky-edison+ (sys_dswci@tlsndgbuild004) #1 SMP PREEMPT Wed Apr 29 03:54:01 CEST 2015
Building boot_params at 0x00090000
Loading bzImage at address 00100000 (5368544 bytes)
Magic signature found
Kernel command line: "rootwait root=PARTUUID=012b3303-34ac-284d-99b4-34e03a2335f4 rootfstype=ext4 console=ttyMFD2 earlyprintk=ttyMFD2,keep loglevel=4 g_multi.ethernet_config=cdc systemd.unit=multi-user.target hardware_id=00 g_multi.iSerialNumber=88a7cbd65118ecb7cbe1fde0dd5174df g_multi.dev_addr=02:00:86:51:74:df platform_mrfld_audio.audio_codec=dummy"

Starting kernel ...

[ 0.760411] pca953x 1-0020: failed reading register
[ 0.765618] pca953x 1-0021: failed reading register
[ 0.770719] pca953x 1-0022: failed reading register
[ 0.775838] pca953x 1-0023: failed reading register
[ 1.623920] snd_soc_sst_platform: Enter:sst_soc_probe
[ 2.028440] pmic_ccsm pmic_ccsm: Error reading battery profile from battid frmwrk
[ 2.046563] pmic_ccsm pmic_ccsm: Battery Over heat exception
[ 2.046634] pmic_ccsm pmic_ccsm: Battery0 temperature inside boundary

Welcome to CentOS Linux 7 (Beta)!

Expecting device dev-ttyMFD2.device...
[ OK ] Reached target Remote File Systems.
[ OK ] Listening on Delayed Shutdown Socket.
[ OK ] Listening on /dev/initctl Compatibility Named Pipe.
[ OK ] Listening on Journal Socket.
Mounting Debug File System...
Starting Apply Kernel Variables...
Starting Create list of required static device nodes...rrent kernel...
Mounting POSIX Message Queue File System...
Starting Setup Virtual Console...
Mounting Configuration File System...
Mounting FUSE Control File System...
Starting Journal Service...
[ OK ] Started Journal Service.
[ OK ] Listening on udev Kernel Socket.
[ OK ] Listening on udev Control Socket.
Starting udev Coldplug all Devices...
[ OK ] Reached target Encrypted Volumes.
[ OK ] Set up automount Arbitrary Executable File Formats F...utomount Point.
[ OK ] Reached target Swap.
Starting Remount Root and Kernel File Systems...
Expecting device dev-disk-by\x2dpartlabel-home.device...
[ OK ] Created slice Root Slice.
[ OK ] Created slice User and Session Slice.
[ OK ] Created slice System Slice.
[ OK ] Reached target Slices.
[ OK ] Created slice system-getty.slice.
[ OK ] Created slice system-serial\x2dgetty.slice.
[ OK ] Mounted Debug File System.
[ OK ] Started Apply Kernel Variables.
[ OK ] Mounted POSIX Message Queue File System.
[ OK ] Started Setup Virtual Console.
[ OK ] Mounted Configuration File System.
[ OK ] Mounted FUSE Control File System.
[ OK ] Started Remount Root and Kernel File Systems.
[ OK ] Started Create list of required static device nodes ...current kernel.
Starting Create static device nodes in /dev...
Starting Load/Save Random Seed...
Starting Configure read-only root support...
[ OK ] Started udev Coldplug all Devices.
[ OK ] Started Create static device nodes in /dev.
[ OK ] Started Load/Save Random Seed.
[ OK ] Started Configure read-only root support.
Starting udev Kernel Device Manager...
[ OK ] Reached target Local File Systems (Pre).
[ OK ] Started udev Kernel Device Manager.
[ OK ] Found device /dev/ttyMFD2.
[ OK ] Found device /dev/disk/by-partlabel/home.
Mounting /home...
[ OK ] Reached target Sound Card.
[ OK ] Mounted /home.
[ OK ] Reached target Local File Systems.
Starting Trigger Flushing of Journal to Persistent Storage...
Starting Create Volatile Files and Directories...
[ OK ] Started Trigger Flushing of Journal to Persistent Storage.
[ OK ] Started Create Volatile Files and Directories.
Starting Update UTMP about System Reboot/Shutdown...
[ OK ] Started Update UTMP about System Reboot/Shutdown.
[ OK ] Reached target System Initialization.
[ OK ] Reached target Timers.
[ OK ] Reached target Paths.
[ OK ] Listening on D-Bus System Message Bus Socket.
[ OK ] Reached target Sockets.
[ OK ] Reached target Basic System.
Starting firewalld - dynamic firewall daemon...
Starting Dump dmesg to /var/log/dmesg...
Starting Disable the watchdog device on the Intel Edison...
[ 7.665241] intel_scu_watchdog_evo: watchdog_stop
Starting Permit User Sessions...
Starting Login Service...
Starting D-Bus System Message Bus...
[ OK ] Started D-Bus System Message Bus.
Starting LSB: Bring up/down networking...
[ OK ] Started Dump dmesg to /var/log/dmesg.
[ OK ] Started Disable the watchdog device on the Intel Edison.
[ OK ] Started Permit User Sessions.
[ OK ] Started LSB: Bring up/down networking.
Starting Getty on tty1...
[ OK ] Started Getty on tty1.
Starting Serial Getty on ttyMFD2...
[ OK ] Started Serial Getty on ttyMFD2.
[ OK ] Reached target Login Prompts.
[ OK ] Started Login Service.
[ OK ] Reached target Multi-User System.

CentOS Linux 7 (Beta)
Kernel 3.10.17-poky-edison+ on an i686

localhost login:

Connecting the WiFi Interface

From here, you can connect using the onboard wireless controller:

# Modify /etc/sysconfig/wpa_supplicant to include your device
INTERFACES="-iwlan0"

# Add your network to the wpa_supplicant config
root@edison# wpa_passphrase MyHomeSSID "PasswordToMYWifi" > /etc/wpa_supplicant/wpa_supplicant.conf

# Start the wpa_supplicant service
root@edison# systemctl enable wpa_supplicant
root@edison# systemctl start wpa_supplicant

# Get an address on the interface
root@edison# dhclient wlan0

Known Issues

• The disable-watchdog service starts late in the boot process, so touching
  /.autorelabel will result in a bootloop (the watchdog timer times out before
  the selinux relabel is finished)
• We're still using and distributing the Kernel from the toolkit, we will be
  working on building a CentOS kernel which may also allow for a 64-bit userland