Xenomai on Foxg20

Xenomai is a real-time development framework cooperating with the Linux kernel, in order to provide a pervasive, interface-agnostic, hard real-time support to user-space applications, seamlessly integrated into the GNU/Linux environment.

We now see how to install it on FoxG20.

Download the source tree

On your Linux PC move to your home directory and download the standard kernel source tree from Internet typing:

$ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.35.9.tar.bz2
$ tar -xvjf linux-2.6.35.9.tar.bz2

Applying the patches for the FOX Board G20

Download extract these patches to your new linux source directory and apply them: 0001_xenomai_foxg2_2_6_35_9

$ patch -p1 < 0001_xenomai_foxg2_2_6_35_9.patch

Configuring your Kernel

For custom config you kernel choose you must now configure it:

$ make menuconfig

Building Your Kernel

Once you are happy with your kernel configuration you can build a new kernel with:

$ make

When finished you will find a new uImage file containing the kernel image. This file have to be copied on the first FAT16 partition of your microSD card as described next.

If you require to compile the Kernel modules type also:

$ make modules
$ make modules_install

Note that modules are not installed but rather all copied to the ./FoxModules sub-directory. If you don't want old modules you've build before then instead of that last line do:

$ rm -rf ./FoxModules
$ make modules_install

Creating Your Initial Root File Store

Debian comes with a useful tool for systems installers called debootstrap that eases creating your initial root file store.

To get debootstrap (in case it's not yet installed on your Ubuntu distro), type:

sudo apt-get install debootstrap

debootstrap is usually run in two stages. The first stage is on a working Debian (or Ubuntu) machine to create a very basic area. The second stage is run on the target machine (in this case your Netus) to fill in that area.

The steps are detailed and minor mistakes can lead to an unbootable system or a system that is highly unreliable.

To make life easier you can use this shell script: gen_root3.sh

There are some settings at the start of the script that you may want to change. In particular:

# Where to get Debian files from - pick one local to you!
url=http://ftp.uk.debian.org/debian

You can find the official list of alternate mirrors here: http://www.debian.org/mirror/list

# This MUST match the version of the kernel you are using on your target
kernel_version=2.6.35.9
# Either set eth=static and then also address, netmask and gateway
# OR set eth=dhcp
# Comment out which ever you are NOT using
# Target machine network details
eth=static
address=192.168.1.90
netmask=255.255.255.0
gateway=192.168.1.1
#eth=dhcp

Once edited gen_root3.sh has to be run as root (it is a requirement of debootstrap):

sudo ./gen_root3.sh

When the script runs, it will create the sub-directory armel-root in the Linux directory and will copy the first stage bootstrap files in there.

Once completed, you need to copy the contents of the directory armel-root to the root area of your microSD. If your microSD card uses the recommended Debian layout and is mounted in your (Debian/Ubuntu) host then you can copy it with:

sudo cp -rp armel-root/. /media/rootfs
sync

Compile Xenomai

Xenomai will now be crosscompiled for ARM platform:

$ wget http://download.gna.org/xenomai/stable/xenomai-2.5.6.tar.bz2

$ tar -xvjf xenomai-2.5.6.tar.bz2
$ cd $xenomai_root

$ ./configure --host=arm-linux-gnueabi --enable-arm-eabi --enable-arm-mach=at91sam9 --disable-arm-tsc

$ make DESTDIR=/destination/of/xenomai/ install

finally copy the files of Xenomai in the root store.

$ cd /destination/of/xenomai/usr/

$ sudo cp -R xenomai/ /media/rootfs/usr/

$ cd ..

$ cd dev

$ sudo cp -R * /media/rootfs/dev/

Copy modules on root file store

Now we copy the kernel modules:

$ cd linux-2.6.35.9/FoxModules/lib

$ sudo cp -R firmware/ /media/rootfs/lib/

$ sudo cp -R modules/ /media/rootfs/lib/

$ sync

Installing

Now unmount your microSD card, transfer it to your Netus and boot.

I strongly advise you to have a console cable (e.g. using the Debug Port Interface) in place so you can monitor stage2's progress

Depending on your network connection (and the speed/load of the Debian repository) stage2 can take 30 minutes or more to complete. At which time the Netus will reboot automatically into multi-user Debian.

You can login as root with no password.

I STRONGLY advise that your first steps are to set a root password (the Netus root password used elsewhere is netusg20) and then to run:

apt-get update
apt-get install locales
dpkg-reconfigure locales

At the very least this will stop perl (and everything that uses perl) from complaining about locale issues!

Some locales run out of memory when you try to configure them on the Fox (localedef crashes). If you are hit by this do:

apt-get install locales-all

before running dpkg-reconfigure.

installing locales-all takes a long time - at least 15 minutes!

You now have a basic Debian system running. I suggest you run:

apt-get install ntpdate

Test the xenomai system

Finally, to test the system we can run the command:

$ cd /usr/xenomai/share/xenomai/testsuite/latency/

$ ./run

Latest version

This is the Debian bootable microSD contents used to write the tutorial on this site:

Kernel kernel_lenny_xenomai_2_6_35_9.tar.bz2

Rootfs rootfs_lenny_xenomai.tar.bz2

Thanks acmesystems for their work.

For more information visit http://www.acmesystems.it/

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