Embedded Linux training update: Atmel Xplained, and more!

Atmel SAMA5D3 Xplained boardWe are happy to announce that we have published a significant update of our Embedded Linux training course. As all our training materials, this update is freely available for everyone, under a Creative Commons (CC-BY-SA) license.

This update brings the following major improvements to the training session:

  • The hardware platform used for all the practical labs is the Atmel SAMA5D3 Xplained platform, a popular platform that features the ARMv7 compatible Atmel SAMA5D3 processor on a board with expansion headers compatible with Arduino shields. The fact that the platform is very well supported by the mainline Linux kernel, and the easy access to a wide range of Arduino shields makes it a very useful prototyping platform for many projects. Of course, as usual, participants to our public training sessions keep their board after the end of the course! Note we continue to support the IGEPv2 board from ISEE for customers who prefer this option.
  • The practical labs that consist in Cross-compiling third party libraries and applications and Working with Buildroot now use a USB audio device connected to the Xplained board on the hardware side, and various audio libraries/applications on the software side. This replaces our previous labs which were using DirectFB as an example of a graphical library used in a system emulated under QEMU. We indeed believe that practical labs on real hardware are much more interesting and exciting.
  • Many updates were made to various software components used in the training session: the toolchain components were all updated and we now use a hard float toolchain, more recent U-Boot and Linux kernel versions are used, etc.

The training materials are available as pre-compiled PDF (slides, labs, agenda), but their source code in also available in our Git repository.

If you are interested in this training session, see the dates of our public training sessions, or order one to be held at your location. Do not hesitate to contact us at training@bootlin.com for further details!

It is worth mentioning that for the purpose of the development of this training session, we did a few contributions to open-source projects:

Thanks a lot to our engineers Maxime Ripard and Alexandre Belloni, who worked on this major update of our training session.

Embedded Linux course in Madrid – July 7-11

We are happy to announce a new Embedded Linux training course on July 7-11, in Madrid, Spain.

IGEPv2 boardIt is organized by our partners ISEE (the makers of the IGEPv2 board that we are using in this course), and Silica, a well known component is distributor who is welcoming the session in its offices in Madrid.

The course will be instructed in English by our trainer Marcin Bis. Marcin Bis

The registrations are directly handled by ISEE. See details.

Android training sessions in the UK

Bootlin is happy to announce its first public training session outside of France.

British Android robot logo

Of course, we deliver training courses on customer sites all around the world, but this will be the first one open to individual registration that we organize outside of France.

We are starting with an Android system development session in Southampton, UK.

You will enjoy the newest version of our Android course, based on Android 4.x, and using the BeagleBone Black as the development platform for the practical labs. As always in our training sessions, participants walk away with the board used during the practical labs (in this case the BeagleBone Black and its LCD cape), allowing them to continue their learning and experiments well after the end of the course.

Being a popular cruising destination, Southampton is easy to reach from other cities in the UK and in the world.

The Android robot picture is copyrighted by Google. It is licensed under the Creative Commons 3.0 Attribution Unported license. The British robot version has been derived by Bootlin, and is available under the same license. Feel free to reuse it and improve it as long as you keep the original author!

New training materials: boot time reduction workshop

We are happy to release new training materials that we have developed in 2013 with funding from Atmel Corporation.

The materials correspond to a 1-day embedded Linux boot time reduction workshop. In addition to boot time reduction theory, consolidating some of our experience from our embedded Linux boot time reduction projects, the workshop allows participants to practice with the most common techniques. This is done on SAMA5D3x Evaluation Kits from Atmel.

The system to optimize is a video demo from Atmel. We reduce the time to start a GStreamer based video player. During the practical labs, you will practice with techniques to:

  • Measure the various steps of the boot process
  • Analyze time spent starting system services, using bootchartd
  • Simplify your init scripts
  • Trace application startup with strace
  • Find kernel functions taking the most time during the boot process
  • Reduce kernel size and boot time
  • Replace U-Boot by the Barebox bootloader, and save a lot of time
    thanks to the activation of the data cache.

Creative commonsAs usual, our training materials are available under the terms of the Creative Commons Attribution-ShareAlike 3.0 license. This essentially means that you are free to download, distribute and even modify them, provided you mention us as the original authors and that you share these documents under the same conditions.

Special thanks to Atmel for allowing us to share these new materials under this license!

Here are the documents at last:

The first public session of this workshop will be announced in the next weeks.
Don’t hesitate to contact us if you are interested in organizing a session on your site.

Updated version of our kernel driver development course: Device Tree, BeagleBone Black, Wii Nunchuk, and more!

BeagleBone Black connected to the Wii Nunchuk over I2C
In the last few years, the practical labs of our Embedded Linux kernel and driver development training were based on the ARMv5 Calao USB-A9263 platform, and covering the ARM kernel support as it was a few years ago. While we do regularly update our training session materials, with all the changes that occurred in the ARM kernel world over the last two years, it was time to make more radical changes to this training course. This update is now available since last month, and we’ve already successfully given several sessions of this updated course.

The major improvements and updates are:

  • All the practical labs are now done on the highly popular ARMv7 based BeagleBone Black, which offers much more expansion capabilities than the Calao USB-A9263 platform we were using. This also means that participants to our public training sessions keep the BeagleBone Black with them after the session!
  • All the course materials and practical labs were updated to cover and use the Device Tree mechanism. We also for example cover how to configure pin muxing on the BeagleBone Black through the Device Tree.
  • The training course is now centered around the development of two device drivers:
    1. A driver for the Wii Nunchuk. This device is connected over I2C to the BeagleBone Black, and we detail, step by step, how to write a driver that communicates over I2C with the device and then exposes the device functionalities to userspace through the input kernel subsystem.
    2. A minimal driver for the OMAP UART, which we use to illustrate how to interface with memory-mapped devices: mapping I/O registers, accessing them, handling interrupts, putting processes to sleep and waking them up, etc. We expose some minimal functionality of the device to userspace through the misc kernel subsystem. This subsystem is useful to expose the functionalities of non-standard types of devices, such as custom devices implemented inside FPGAs.

And as usual, all the training materials are freely available, under a Creative Commons license, so you can study in detail the contents of the training session. It is also worth mentioning that this training session is taught by Bootlin engineers having practical and visible experience in kernel development, as can be seen in the contributions we made in the latest kernel releases: 3.9, 3.10, 3.11 and 3.12.

For details about cost and registration, see our Training cost and registration page.

Announcing our “Android System Development” training

Android RobotFor multiple years, Bootlin has provided two typical training courses for embedded Linux developers: an Embedded Linux system development course that focuses on the basics for embedded Linux development (bootloader and kernel configuration, compiling and usage, system integration and build systems, cross-compiling, filesystems, application development and debugging, etc.) and an embedded Linux kernel and driver development course that focuses on kernel and driver development (kernel APIs for drivers, character drivers, device model, power management, kernel porting, etc.). In total, we have given dozens of editions of these sessions in multiple locations all around the world. We have kept our commitment to release all the training materials under a free license (the Creative Commons CC-BY-SA license), and they are therefore freely accessible for anyone at /docs/.

We are now announcing a new course, called Android System Development. It is a four day training session that targets engineers who need to develop embedded systems with Google Android.

Through theory and practical labs, the course makes you familiar with compiling and booting Android, with adapting Android to support a new embedded board (assuming that it is already supported by the Linux kernel), and with building a real system through accessing specific hardware, customizing the filesystem and using debugging techniques. See the complete agenda. The training materials for this session will also be made available under the same Creative Commons CC-BY-SA license.

If you are interested in this training session, you can:

  • Join the public session organized in Toulouse, France, on June 11-14, 2012.
  • Order an on-site training session to be held at your location. See registration details.

This training course will be given by our engineer Maxime Ripard who has gained Android experience by working at Archos on Android tablets, by making Android work on multiple TI OMAP3 based platforms and also by participating to the Android Builders Summit conference.

Do not hesitate to contact us for further details about this new training course.

Embedded Linux training: switch to the IGEPv2 board

Since early 2009, our training sessions have been using the USB-A9263 board from Calao Systems as the hardware platform for the practical labs. However, this AT91-based platform was getting older, and we therefore started the process of switching our training sessions to a new hardware platform, the IGEPv2 board from ISEE.

IGEPv2 board
IGEPv2 board

The IGEPv2 platform is very similar to the popular BeagleBoard and BeagleBoard-XM platforms, and has the following technical characteristics :

  • TI DM3730, which is the latest OMAP3 processor from Texas Instruments, clocked at 1 Ghz, and including a DSP for signal processing, an IVA block for audio/video decoding and the PowerVR SGX for 3D/OpenGL. This processor offers far more possibilities than the AT91 one, especially for multimedia applications.
  • 512 MB of RAM and 512 MB of OneNAND flash.
  • Integrated Ethernet connector, Wifi and Bluetooth connectivity.
  • One USB OTG port and one USB host port.
  • A microSD connector.
  • A DVI-D connector (HDMI), stereo input and ouput
  • RS232 connector
  • Multiple expansion ports to access LCD, camera, I2C, SPI, JTAG, etc. signals

Compared to the BeagleBoard-XM, this board has the following advantages:

  • it has a OneNAND Flash device, which allows us to demonstrate and practice the usage of MTD and Linux flash-specific filesystems such as JFFS2 and UBIFS in our training sessions. Even though block-based storage such as SD and eMMC is more and more popular in consumer-electronic devices, usage of raw NAND flash is still very common in industrial applications, and we therefore wanted to keep presenting those devices and their usage in embedded Linux
  • ISEE, the company manufacturing the IGEPv2, is located in Spain, which makes it easier for us to regularly order boards from them, since we are also located in Europe
  • the board provides Bluetooth and Wifi connectivity, which is nice

We have already given two sessions of our Embedded Linux system development training with the IGEPv2, and all our future sessions of this training will use this hardware platform, so the participants will benefit from a more modern platform, with far more capabilities than our previous AT91-based training hardware. This is also the board we are now giving to the participants to our public training sessions, so those participants come back home with a very nice and powerful platform which allows countless experiments around embedded Linux. Note that we also intend to port our Embedded Linux kernel and driver development training session to the IGEPv2 platform in the near future.

Embedded Linux practical labs with the Beagle Board

Beagle boardGet valuable embedded Linux experience using our practical labs on a Beagle Board.

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…