Hi all,
I have been spending some effort on making ROS compiling for the gumstix
and I'd like to share the experience:
First of all, I have tried the approach listed on the wiki, and they are
not my favourite but they provide a good basis.
The first thing I have done is installing ubuntu on the gumstix (a guide
for that can be found on
http://johnwoconnor.blogspot.com/2009/04/installing-ubuntu-on-gumstix-overo.html)
This simplifies a lot the process of getting all the 3rd party libraries
compiled (in particular boost, xmlrpc++, log4cxx, apr can then just be
obtained using an apt-get call).
Once you have installed ubuntu on the gumstix, you could in theory
install all the -dev packages and gcc/g++ and compile everything
natively. Needless to say that it might be a little bit long given the
performances of the gumstix. However, this is a working solution.
The second solution is to run a gumstix image using qemu and in
particular qemu-system-arm (package qemu-kvm-extras in ubuntu 9.10). To
this end, you first need to setup a disk image, mount it, copy the file
system created using the link above.
#> qemu-img create overo-ros.img 2G
#> mkdir overo-ros
#> mount -o loop overo-ros.img overo-ros
#> cd overo-ros
#> sudo tar -zxvf /path/to/armel-rootfs-YYYYMMDDhhmm.tgz
At this point the file system can be umounted and launched with qemu
(get the kernel by following the instruction at
http://people.canonical.com/~ogra/arm/qemu/README)
#> umount overo-ros
#> sudo qemu-system-arm -M versatilepb -kernel vmlinuz-2.6.28-versatile
-hda overo-ros.img -m 256M -append "root=/dev/sda" -net nic -net user
I have not tried booting the image while it is still mounted. I suspect
it does not work so well.
Once qemu has started the image, one can easily apt-get arm packages and
update the image to get all the -dev packages. It is also possible to
install gcc and compile all ros in the virtual gumstix. However, this
takes forever, even longer than on the real system.
However, getting qemu running is not a loss of time. Once all the -dev
packets have been installed, the ubuntu image can be used to
cross-compile. To this end, I first quit qemu, and remount overo-ros.
The following will assume you have a a cross compiler installed, for
instance through buildroot or open-embedded (check the gumstix wiki). We
can then use the -sysroot option of gcc to compile using the overo-ros
directory as the root of the filesystem (where /usr/include and /usr/lib
are looked for). However, at the time of this writing libtool is not
able to pass a -sysroot option to gcc, so I write a set of scripts for
gcc, g++ and cpp, respectively called gcc-sysroot, g++-sysroot, and
cpp-sysroot. The scripts are as follows:
#!/bin/bash
if test -n "$ARM_SYSROOT"
then
SYSROOT=--sysroot=$ARM_SYSROOT
fi
exec ${0/-sysroot/} $SYSROOT $*
The same script can be used for all the executable as it find which
binary to call based on how it was called.
Once the scripts are defined, I have a special gumstix compilation
environment:
export GUMSTIXTOP=$HOME/overo-oe/
export OVEROROOT=$HOME/overobuntu/overo-ros
export
PKG_CONFIG_PATH=$OVEROROOT/usr/local/lib/pkgconfig:$OVEROROOT/usr/lib/pkgconfig
export ARM_SYSROOT=$OVEROROOT
export CROSSBIN=$GUMSTIXTOP/tmp/cross/armv7a/arm-angstrom-linux-gnueabi/bin
export PATH=$CROSSBIN:$PATH
export AR=$CROSSBIN/ar
export CPP=$CROSSBIN/cpp-sysroot
export CXX=$CROSSBIN/g++-sysroot
export CC=$CROSSBIN/gcc-sysroot
Once this is sourced in the current shell, you can call rosmake
normally, and everything should be able to compile. Obviously, rosdep
install does not work (you have to restart the qemu thing and call
apt-get from there, or at least that the easy solution I found). I have
all the laser and image processing stack working in particular, even
libdc1394 with the usb drivers for the pointgrey cameras.
Please note that you need to recall "cmake ." in all the directories.
This can be done for instance with a script such as: (not fully tested)
roscd
find . -name "CMakeCache.txt" | while read line
do
cd ${line/build\/CMakeCache.txt/}
cmake .
cd -
done
Beware that a couple of binary must be compiled native and crossed
(rospack, rosstack and rosmsg). To this end, compile them first native,
save them (for instance renaming it rospack.intel), then compile them
crossed, save the crossed compilation for later installation (for
instance renaming it rospack.arm), then make a link to the correct
executable for the current architecture, and mark these directory
ROS_NOBUILD (touch ROS_NOBUILD). This also applies to libraries such as
librospack.so and librosstack.so. I hope the WillowGarage team finds a
way to decouple these libraries for cross-compilation.
It might also be necessary to delete all the .la files installed with
the -dev package in ubuntu on the arm image. These files refers libtool
to some libraries in /usr/include and /usr/lib, without using the
-sysroot option. gcc/g++ sees the risk and does not accept to compile
then. This is a problem in particular for libjpeg (compressed image
transport).
Using all the above, I have ros working on both the gumstix overo and
verdex. On the overo, using wifi G, the gumstix can downstream telemetry
data and video data from an helicopter, using either raw images or
jpeg-compressed images (not much framerate gain).
On the verdex, I need to change the timeout in rospy/client.py (TBC) to
20seconds as it is the time the systems needs to get roscore up and
running (The disk access performance are extremely bad on this older
board). If someone wants to run ROS on a verdex, please contact me, and
I'll check exactly what I had to change to make it happen. Not that the
file system mentioned above works for a verdex.
Check on
http://support.skybotix.com/downloads.php for a full filesystem
for the gumstix overo, with ros pre-compiled (Skybotix is a company
selling micro-helicopter with an embedded gumstix, but the file system
should be a good starting point for any gumstix application)
I hope all this information helps...
--
Dr. Cedric Pradalier
http://www.asl.ethz.ch/people/cedricp
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