Category: News

ELC 2010 program announced

Japantown, San FranciscoThe program of talks and BOFs of the 2010 edition of the Embedded Linux Conference has been published a few days ago, an opportunity to look at the most important and interesting conference for embedded Linux developers. For the record, ELC 2010 will take place from April, 12th to April, 14th in San Francisco, CA, USA, in the same place as the 2009 edition.

A nice set of talks

  • A set of real-time related talks: Real-Time Linux Failure, by Frank Rowand (works for Sony, well known for his preempt-rt related talks at various ELC conferences), Effective Use of RT-Preempt, by Kevin Dankwardt, Using Interrupt Threads to Prioritize Interrupts, by Mike Anderson (also well known for his very interactive talks, he will also be giving his traditional Using JTAG to debug Linux device drivers tutorial), Measuring Responsiveness of Linux Kernel on Embedded System, by YungJoon Jung and DongHyouk Lim.
  • A talk by Grant Likely about Flattened Device Tree ARM support update, an effort to convert the ARM architecture to the same organization used in PowerPC, with a device tree file describing the hardware details instead of platform_device definitions in plain C. An important change for anyone doing ARM kernel development.
  • Several power-management related talks: Runtime Power Management: Overview and Platform Implementation, by Kevin Hillman (who works for Deep Root Systems and has done a huge amount of work in the OMAP power management area). Runtime Power Management is probably the most important change done recently to the power management infrastructure of the Linux kernel, so this talk is certainly worth a look, all the more as Kevin is a very good speaker. On power manegement, there will also be other talks : DVFS for the Embedded Linux, by Yong Bon Koo and Youngbin Seo, Wake-ups effect on idle power for Intel’s Moorestown MID and smartphone platform, by German Monroy (Intel), Workload based aggressive Power Management on the Intel Moorestown MID and future Intel MID/Smartphone Platforms, by Sujith Thomas (from Intel).
  • Japan Town, San FranciscoThe usual tracing-related talks, with Using the LTTng tracer for system-wide performance analysis and debugging by Mathieu Desnoyers and Ftrace – embedded edition, by Steven Rostedt. A talk on debugging Linux toolchain overview with advanced debugging and tracing features, by Dominique Toupin.
  • Talks about platforms: a keynote by Greg Kroah Hartmann on Android: a case study of an embedded Linux project (during which Greg will probably explain why the Android kernel modifications are not mainlined), Experiences in Android Porting, Lessons learned, tips and tricks, by Mark Gross and Understanding and Developing Applications for the Maemo Platform, by Leandro Melo de Sales, even though the recent merge of Maemo and Moblin to create MeeGo is likely to change some technical aspects of application development for this platform.
  • The question of multi-core now also seems to be present in embedded conferences: Strategies for Migrating Uniprocessor Code to Multi-Core, by Mike Anderson, Embedded Multi-core with Adeos, Dan Malek, Lock-free algorithm for Multi-core architecture, Hiromasa Kanda. Multi-core Scheduling optimizations for soft real-time multi-threaded applications – A cooperation aware approach, Lucas Martins De Marchi.
  • Some security talks, with Mike Anderson (again !) talking about Creating a Secure Router Using SELinux and Jake Edge about Understanding threat models for embedded devices
  • Some more-or-less multimedia-oriented talks: Supporting SoC video subsystems in video4linux, by Hans Verkuil, An Introduction to the Qt Development Framework, by Jeremy Katz, GeeXboX Enna: embedded Media Center, by Benjamin Zores, Case Study – Embedded Linux in a digital television STB, by Melanie Rhianna Lewis
  • In the other talks, I’ve noted the Small Business Owners BOF by Grant Likely, Evaluation of Data Reliability on Linux File Systems by Yoshitake Kobayashi, Porting the Linux Kernel to x86 MID platforms, by Jacob Pan, Linux without a bootloader? by Greg Ungerer, Kexec – Ready for Embedded Linux by Magnus Damn, Custom hardware modeling for FPGAs and Embedded Linux Platforms with QEMU, by John Williams, Edgar Iglesias.

Both Michael Opdenacker and I will be there at ELC. We hope to meet you during this conference!

Buildroot 2010.02 released, contributions from Bootlin!

Buildroot logoBuildroot is a embedded Linux system build system. It automates the process of downloading, configuring, compiling and installating all the components of an embedded Linux system, from Busybox to more complicated software stacks using Gtk, Qt, X.org, Gstreamer, etc. Buildroot is easy to use and extend, making it a nice choice for small to medium-sized embedded Linux systems.

As promised by the fixed-release schedule, a 2010.02 release has been published on Friday, with numerous improvements over the previous version 2009.11, many of which are part of the general cleanup process that the project is doing since the beginning of 2009. These improvements are detailed in the project CHANGES file.

Thomas Petazzoni, from Bootlin, implemented several of these improvements :

  • Creation of a package infrastructure for non-autotools packages. Buildroot had for a long time an infrastructure to factorize the code needed to build packages based on the autotools build systems. But all other packages were using hand-made Makefiles, which were hard to write and generated a lot of code duplication. Therefore, we have introduced an infrastructure that makes adding new packages much easier, and which allows us to cleanup the existing codebase significantly by factorizing a lot of common code. The autotools infrastructure has also been reworked on top of the generic infrastructure to avoid code duplication as well. At the same time, we have significantly improved the documentation on how to add new packages. This infrastructure is a building block that will allow us to easily add more features to all packages in Buildroot (such as package generation).
  • Removal of the external toolchain source mechanism, which was merged with the normal toolchain building procedure. This special casing was implemented to allow the compilation of AVR32 toolchains, but such an additional complexity wasn’t needed. Now, Buildroot continues to build AVR32 toolchains as it used to do, but the code is much cleaner. Another illustration of our large cleanup effort.
  • Many, many, many fixes to different packages, many of them to ensure that we do not depend on development packages being installed on the host. This is very important to ensure that our build procedure is as independent as possible from the development machine configuration.

From the list of contributors, ordered by the number of patches, Thomas Petazzoni of Bootlin has been the first Buildroot contributor for this last release :

$ git shortlog -e -n -s 2009.11..2010.02  (removed e-mail addresses)
139 Thomas Petazzoni
124 Peter Korsgaard
26  Lionel Landwerlin
23  Gustavo Zacarias
7   Julien Boibessot
4   Nigel Kukard
4   Sven Neumann
2   Anders Darander
2   Chris Packham
2   Daniel Mack
2   H Hartley Sweeten
2   Richard van Paasen
2   Will Wagner
2   William Wagner
2   Yann E. MORIN
1   Cameron Hutchison
1   Clark Rawlins
1   Francisco Gonzalez
1   Francisco Gonzalez Morell
1   Hans-Christian Egtvedt
1   Lionel Landwerlin
1   Ormund Williams
1   Rob Alley
1   Sagaert Johan
1   grante

For the next release, we will work on additional cleanup of Buildroot and particularly the target/ directory, which contains the code to build the Linux kernel, different bootloaders, and to generate the final root filesystem image in various formats. Improving support for external toolchains is also on our TODO list : supporting multilib toolchains such as the CodeSoucery toolchain, and fixing a long-standing issue with libtool.

Don’t hesitate to try Buildroot, and to report your successes and failures on the mailing-list, in our bug tracker, or on our IRC channel, #uclibc on Freenode.

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.

Bootlin at ELCE 2009

Grenoble

As usual, we won’t miss this year’s edition of the Embedded Linux Conference Europe, which has always been a great source of information and encounters for embedded Linux developers.

Here are details about our involvement this year.

  • I am part of the organization committee, in particular the coordinator for the Technical Showcase.
  • Taking advantage of his stay in Grenoble, my colleague Thomas Petazzoni will make an embedded Linux presentation on Tuesday, Oct. 13 at 7:30 pm, at GUILDE, the local Linux user group.
  • Thomas and I will be present at the Embedded Systems Exhibition on Wednesday, Oct. 14, sharing a booth with our partner CALAO Systems. The exhibition entry is free of charge, and this will be an excellent opportunity to meet us and have enough time to talk about your topics of interest.
  • Thomas will lead the Buildroot BOF with Peter Korsgaard, Buildroot’s maintainer, at 5:35 pm on Thursday, Oct. 15. This informal session will allow users and developers to meet and exchange ideas.
  • I will be the leader of the Small Business BOF on Thursday 15 at 6:35 pm, an informal session for small embedded Linux companies interested in sharing experience and best practices, and of course to know each other better.
  • I will make a presentation on boot time reduction techniques, at 3:40 on Friday, Oct. 16.
  • Albin Tonnerre, who was an intern at Bootlin this summer, will participate to the Technical Showcase at 12:00 am on Friday, Oct. 16, showing the benefits of LZO decompression on kernel boot time. During his internship, Albin made very nice contributions to boot time reduction, power management on AT91 and to U-boot board support.
  • Thomas Petazzoni will also participate to the Technical Showcase at the same time, showing Buidroot’s new features.
  • We will videotape the conferences we go to and will release the videos later on our website.
  • Thomas organizes a Buildroot developer day on Saturday, Oct. 17, allowing developers to meet and code together. Bootlin will offer lunch to the participants, and the room will be offered by CALAO Systems. There are no more seats left for space reasons.

Hope to see you in Grenoble!

ELC 2009 videos

My Colleague Thomas and I had the privilege to participate to the 2009 edition of the Embedded Linux Conference, which took place in San Francisco, on April 6-8. In spite of the weak economy, this event was once again a success. It attracted major developers from the embedded Linux community, as well as participants from all over the word.

Following the tradition, we are proud to release new videos about this event. These videos were shot by Satoru Ueda and Tim Bird (Sony), and by Thomas Petazzoni and Michael Opdenacker (Bootlin). For the first time, we used an HD camcorder to shoot some of the videos. A higher resolution allows to read the slides projected on the screen. As usual, the videos are released with a Creative Commons Attribution – ShareAlike 3.0 license.

Thomas and I found the following talks particularly interesting:

  • Ubiquitous Linux, by Dirk Hohndel
  • Embedded Linux and Mainline Kernel, by David Woodhouse
  • What are Interrupt Threads and How Do They Work?, by Reece Pollack
  • Visualizing Process Memory, by Matt Mackall
  • KProbes and Systemtap Status, by Tim Bird
  • Deploying LTTng on Exotic Embedded Architectures, by Mathieu Desnoyers
  • Embedded Linux on FPGAs for fun and profit, by Dr John Williams (Petalogix)
  • Linux on Embedded PowerPC porting guide, by Grant Likely
  • Understanding and writing an LLVM Compiler Backend, by Bruno Cardoso Lopes

You may be interested in watching the presentations we made and the BOFs we led:

  • Building Embedded Linux Systems with Buildroot, by Thomas Petazzoni. In these last months, Thomas has made big contributions to this build system.
  • Build tools BOF, by Thomas Petazzoni
  • Update on filesystems for flash storage, by Michael Opdenacker
  • System Size BOF, by Michael Opdenacker

Of course, lots of other talks were very interesting. See the whole list by yourself:

Linux 2.6.30 – New features for embedded systems

Interesting features in Linux 2.6.30 for embedded system developers

Linux 2.6.30 has been released almost 1 month ago and it’s high time to write a little about it. Like every new kernel release, it contains interesting features for embedded system developers.

The first feature that stands out is support for fastboot. Today, most devices are initialized in a sequential way. As scanning and probing the hardware often requires waiting for the devices to be ready, a significant amount of cpu time is wasted in delay loops. The fastboot infrastructure allows to run device initialization routines in parallel, keeping the cpu fully busy and thus reducing boot time in a significant way. Fasboot can be enabled by passing the fastboot parameter in the kernel command line. However, unless your embedded system uses PC hardware, don’t be surprised if you don’t get any boot time reduction yet. If you look at the code, you will see that the async_schedule function is only used by 4 drivers so far, mainly for disk drives. You can see that board support code and most drivers still need to be converted to this new infrastructure. Let’s hope this will progress in future kernel releases, bringing significant boot time savings to everyone.

Tomoyo LinuxLinux 2.6.30 also features the inclusion of Tomoyo Linux, a lightweight Mandatory Access Control system developed by NTT. According to presentations I saw quite a long time ago, Tomoyo can be used as an alternative to SELinux, and it just consumes a very reasonable amount of RAM and storage space. It should interest people making embedded devices which are always connected to the network, and need strong security.

Another nice feature is support for kernel images compressed with bzip2 and lzma, and not just with zlib as it’s been the case of ages. The bzip2 and lzma compressors allow to reduce the size of a compressed kernel in a significant way. This should appeal to everyone interested in saving a few hundreds of kilobytes of storage space. Just beware that decompressing these formats requires more CPU resources, so there may be a price to pay in terms of boot time if you have a slow cpu, like in many embedded systems. On the other hand, if you have a fast cpu and rather slow I/O, like in a PC, you may also see a reduction in boot time. In this case, you would mainly save I/O time copying a smaller kernel to RAM, and with a fast cpu, the extra decompression cost wouldn’t be too high.

However, if you take a closer look at this new feature, you will find that it is only supported on x86 and blackfin. Alain Knaff, the author of the original patches, did summit a patch for the arm architecture, but it didn’t make it this time. Upon my request, Alain posted an update to this arm patch. Unfortunately, decompressing the kernel no longer works after applying this patch. There seems to be something wrong with the decompression code… Stay tuned on the LKML to follow up this issue. Note that the blackfin maintainers took another approach, apparently. They didn’t include any decompression code on this architecture. Instead, they relied on the bootloader to take care of decompression. While this is simpler, at least from the kernel code point of view, this is not a satisfactory solution. It would be best if the arm kernel bootstrap code took care of this task, which would then work with any board and any bootloader.

Another interesting feature is the inclusion of the Microblaze architecture, a soft core cpu on Xilinx FPGAs. This MMU-less core has been supported for quite a long time by uClinux, and it’s good news that it is now supported in the mainline kernel. This guarantees that this cpu will indeed be maintained for a long time, and could thus be a good choice in your designs.

Other noteworthy features are support for threaded interrupt handlers (which shows that work to merge the real-time preempt patches is progressing), ftrace support in 32 and 64 bit powerpc, new tracers, and of course, several new embedded boards and many new device drivers.

As usual, full details can be found on the Linux Kernel Newbies website.

The Bifferboard: tiny, low power embedded x86 board

A nice, cheap and tiny x86 embedded board that runs Linux and just consumes 1W. It has all the basic connectivity you need in an embedded system.

As you may already know, we maintain a list of attractive and Linux friendly embedded boards. Whenever we find a new board that is attractive and meets our strict criteria (supporting Linux or other free kernels, public pricelist, public documentation and website with an English version), we add this board to our list. This way, we don’t forget about any useful board, and we can offer useful guidance to our customers and to any embedded system developer looking for a suitable hardware platform.

Somebody at Bifferos.com has just contacted us to let us know about their Bifferboard product. Here are its announced features:

  • Bifferboard150MHz RDC CPU, Intel 486SX compatible
  • 1 watt power consumption (200mA @5v)
  • 68mm x 28mm x 19mm
  • 32MB SDRAM/1MB Flash
  • OHCI/EHCI USB 2.0
  • 10/100 Ethernet
  • Serial console 115200 baud
  • 4-pin JTAG (can be used as GPIO)
  • 2 GPIO (1 LED, 1 button)
  • Linux 2.6.27.5 + OpenWrt
  • 29 UK pounds

The board has two components: the CPU board, and the I/O one, offering Ethernet and USB host connectivity. For a serial port, you can order a special cable from their shop, which connects to a USB port on your workstation.

Thanks to its low power consumption, the Bifferboard can even be powered by USB. According to its makers, the board can do anything a NSLU2 device can do. It is just cheaper (approximately 33 EUR at the time of this writing).

Last but not least, most Bifferboard hardware can be emulated with QEMU.

While it could also be suitable for mass production projects, it can be at least a nice platform for prototypes, hobby, research and educational projects.

Of course, if you know about other attractive boards that we could add to our list, please post a comment or send us e-mail.

ELC Europe in Grenoble

Grenoble

Just a quick note after the announcement that has just been made at the Embedded Linux Conference (ELC) in San Francisco…

Tim Bird has just announced that the next European edition of ELC will be in Grenoble, France, on October 15-16. As the new conference home page says, it will be colocated with ESWEEK.

We are very excited about this news, as Grenoble is a not only a beautiful place, but also a very dynamic city full of universities and high-tech companies. We will do our best to incite people to attend the conference, and of course to speak about their projects and propose demos.

Bootlin at ELC

My colleague Thomas Petazzoni and I will participate to the Embedded Linux Conference on April 6-8 in San Francisco.

This is an exciting conference with a very interesting program, and we are proud to be part of it:Golden Gate Bridge

If participate to this conference too, and if you are interested in the above topics, or in topics we covered in this blog, don’t hesitate to come and chat with us. We will both arrive on Saturday afternoon, so we could even meet before the conference starts.

If you can’t make it to this conference, we will also shoot and share videos as usual, so at least you won’t miss the technical contents. You will just miss the beer together…