Category: Training

Embedded Linux practical labs with the Beagle Board

Note: the materials for training with the Beagle Board are no longer available, and would be significantly out of date anyway. We advise you to check our Embedded Linux System Development and Linux Kernel and Driver Development training courses for up-to-date instructions that work on cheaper boards, which are still available on the market today. And if you still have an old Beagle board, it will be an interesting exercise to adapt our current labs to run them on such hardware.

We were asked to customize our embedded Linux training session with specific labs on OMAP 3530 hardware. After a successful delivery on the customer site, using Beagle boards, here are our training materials, released as usual under the terms of the Creative Commons Attribution-ShareAlike 3.0 license:

If you are the happy owner of such a board (both attractive and cheap), or are interested in getting one, you can get valuable embedded Linux experience by reading our lecture materials and by taking our practical labs.

Here’s what you would practise with if you decide to take our labs:

  • Build a cross-compiling toolchain with crosstool-NG
  • Compile U-boot and the X-loader and install it on MMC and flash storage.
  • Manipulate Linux kernel sources and apply source patches
  • Configure, compile and boot a Linux kernel for an emulated PC target
  • Configure, cross-compile and boot a Linux kernel on your Beagle Board
  • Build a tiny filesystem from scratch, based on BusyBox, and with a web server interface. Practice with NFS booting.
  • Put your filesystem on MMC storage, replacing NFS. Practice with SquashFS.
  • Put your filesystem on internal NAND flash storage. Practice with JFFS2 too.
  • Manually cross-compile libraries (zlib, libpng, libjpeg, FreeType and DirectFB) and a DirectFB examples, getting familiar with the tricks required to cross-compile components provided by the community.
  • Build the same kind of graphical system automatically with Buildroot.
  • Compile your own application against existing libraries. Debug a target application with strace, ltrace and gdbserver running on the target.
  • Do experiments with the rt-preempt patches. Measure scheduling latency improvements.
  • Implement hotplugging with mdev, BusyBox’s lightweight alternative to udev.

Note that the labs were tested with Rev. C boards, but are also supposed to work fine with Rev. B ones. You may also be able to reuse some of our instructions with other boards with a TI OMAP3 processor.

Of course, if you like the materials, you can also ask your company to order such a training session from us. We will be delighted to come to your place and spend time with you and your colleagues.

USB-Ethernet device for Linux

Useful device when you work with an embedded development board

For our Embedded Linux training sessions, I was looking for a USB to Ethernet device. Since Linux supported devices are often difficult to find, I’m glad to share my investigations here.

When you use an embedded development board, you must connect it to your computer with an Ethernet cable, for example to transfer a new kernel image to U-boot through tftp, or to make your board boot on a directory on your workstation, exported with NFS.

You could connect both the board and computer to your local network, which would still allow your computer to connect to the Internet while you work with the board. However, you may create conflicts on your local network if you don’t use DHCP to assign an IP address to your board (if your DHCP server even accepts this new device on the network). In a training environment, you are also likely to run out of Ethernet outlets in the training room if you have to connect 8 such boards. Hence, a direct connection between the board and your workstation’s Ethernet port is often the most convenient solution.

If you can’t use WIFI to keep your computer connected to the outside world, a good solution is to add an extra Ethernet port to your computer by using an USB-to-Ethernet device.

My colleague Thomas and I started looking for such devices that would be supported by Linux. Here are a few that we found:

  • D-Link DUB-E100. Supported by the USB_NET_AX8817X driver. However, this product is bulky and quite heavy (at least 100 grams).
  • TRENDnet TU2-E100. Supported by the same driver, but still bulk (August 2015 update: now replaced by a more recent version, now almost as small as the Apple one, and supported out of the box in Linux. See the comment about this device.)
  • Linksys USB 200m. Supported by the same Linux driver and has a much more acceptable size, but customer reviews complain that its connector can break easily.
  • Apple USB Ethernet Adapter. This should be working out of the box in Linux. At least the MB442Z/A or MC704ZM/A references did, but Apple now sells a new reference that might have a different chipset. It is beautiful, small and light. Support for this device (at least the references I mentioned) was added to Linux 2.6.26 through the same driver. You should be able to use it in recent distros.

Apple USB to EthernetSo, I recommend the Apple device. I event posted a comment on the Apple Store, titled “Perfect for Linux”! I hope the Apple droids won’t censor it. Don’t hesitate to buy it, so that we can confirm that the latest reference is supported too.

I can’t tell whether this could happen with Apple. This was the first Apple device I ever bought…

Public session changes

New agenda, sessions in Grenoble, and walking away with an embedded board

Did you notice? We’ve made significant changes to our next public training sessions.

First of all, partnering with CALAO Systems, we are opening new public sessions in Grenoble.

In the upcoming sessions, we also offer a new training agenda, covering embedded Linux system development in full detail. Until recently, our public trainings dedicated approximately 3 days to kernel integration and device driver development, and only 2 days to real-time and to developing the system itself. The new sessions will still cover kernel configuration, (cross)compiling and usage, but will leave Linux kernel and driver development to dedicated sessions.

The new training sessions will thus cover the below topics:

  • Introduction to embedded Linux
  • Bootloaders
  • Configuring, (cross)compiling and booting a Linux kernel
  • Block filesystems
  • Flash filesystems – Manipulating flash partitions
  • C library and cross-compiling toolchains
  • Embedded system development tools
  • BusyBox and other lightweight tools for embedded systems. Graphical toolkits
  • Debugging and profiling tools
  • Implementing realtime requirements
  • Udev and hotplugging
  • System optimizations
  • Practical lab: implementing a multimedia system

For the first time too, each participant will walk away with an embedded board from CALAO systems. After the training sessions, you will then be able to go on practicing with the new technologies that you discovered, and to build your own system prototypes.

You will find more details in the description of our public training sessions.

If there is enough demand, we will propose other public sessions in September 2009, this time on Linux kernel and device driver development. Don’t hesitate to contact us if you are interested in such a session. We could even make it earlier if enough people are interested.

Real hardware in our training sessions

At last, real hardware in our training sessions

If you haven’t had a look at our new training agendas, you may not have noticed that we now use real hardware in our embedded Linux and kernel training sessions. For 4 years, we had been using the QEMU emulator on the x86, arm and mips platforms. While this simplified training session logistics, and avoided any trouble due to hardware failures, this was not close enough to the real world situations that our customers face.

We chose the nifty boards from Calao Systems. They have great features that make them very attractive for training and prototyping purposes

  • AT91SAM9263 ARM CPU from ATMEL, running at 200 MHz
  • 64 MB of RAM and 256 MB of flash, which are more than enough for any embedded system we can think of.
  • Small and light (30 g), with a USB connector replacing power, serial and JTAG connectors, making it easy to travel with several of these devices without having to carry many heavy accessories. Carrying convenience was a key decision factor.
  • 100 Mbit Ethernet port, allowing to practice with root filesystems on NFS, and with tftp from the U-boot command line.
  • CALAO USB 92632 USB 2.0 host ports, allowing to connect any type of device. In particular, we are thinking about USB mass storage and webcam devices.
  • 1 USB device port, allowing to experiment with Linux USB gadget drivers.
  • Very affordable price (less than 160 €).

On the software side, this board is also very attractive:

  • It is supported by the mainline Linux kernel, since version 2.6.27.
  • A bricked board can be reflashed without ever needing to use Windows, thanks the Linux version of Atmel’s SAM-BA utility.
  • It will soon be supported by the mainline version of U-boot. We are contributing to this.
  • It should also be directly supported in the mainline version of Buildroot in the next months, making it easy to build complete root filesystems for it. We will also work on this.

We will also soon offer training cost options that include these boards. This way, customers can walk away with their own device and easily continue to practice with the training hardware and make prototypes, without having to go through an extra purchasing process.

Many new training materials

12 pages with new training materials!

We are happy to release many new training materials that we created along the course of 2008, for our embedded Linux and kernel training sessions:

Many thanks to customers who asked us to cover new topics!

This is actually the tip of the iceberg (with penguins standing on top of it, of course). The documents that have been around for a long time have also undergone significant improvements and have been updated every time new versions with interesting features were released. We are doing our best to keep our training sessions up to date, and this keeps us pretty busy! So, if you haven’t had a look at these documents for a while, you will probably learn new things if you open them again.

Why so many documents at once? Well, we usually try to release the new documents that we create as early as possible. Here are a few excuses for doing this late this time:

  • We’ve had a very busy year (new training sessions, development and service work), preventing us from polishing our new documents and creating new pages describing them.
  • The switch to our new website took more time than expected. We were reluctant to add more pages that would have caused more migration work, and we were also busy deploying the KVM virtualization technology on our new server.
  • We are also switching the documents to a new template, which leaves more space for real content and less space for logos and for information repeated on every page. This work is far from being over yet!
  • We couldn’t release them for National Security reasons Winking smiley.

Now that there’s no infrastructure work left, and that we have run out of excuses (except the one about being busy, we still are), we should be able to release our new documents much earlier.

So, stay tuned on our RSS feed, more will come soon!

Linux USB drivers

Learning how to write USB device drivers for Linux

Bootlin is proud to release a new set of training slides from its embedded Linux training materials. These new ones cover writing USB device drivers for Linux.

Like everything we create, these new materials are released to the user and developer community under a free license. They can be freely downloaded, copied, distributed or even modified according to the terms of the Creative Commons Attribution-ShareAlike 2.5 license.

Free embedded Linux training materials

Bootlin embedded Linux training materials freely available

This was our first, initial annoucement in 2004. Since then, we have made huge improvements to our embedded Linux and Linux kernel and device driver development training courses. See all our training materials.

The 500 page materials of Bootlin’sembedded Linux training have just been published.

They are all released under the terms of the “GNU Free Documentation License (with no invariant sections).

Full training materials

Presentations