Slide decks from talks by the staff of embedded Linux development specialist Free Electrons at Embedded Linux Conference 2014 are now available for free download.

The talks cover a wide range of challenges and issues associated with porting Linux or Android to new embedded hardware platforms and SoCs. Topics include overviews of Buildroot, Yocto, and the Device Tree; discussions of issues such as SMP support and boot-time reduction; and an example of supporting a new ARM-based SoC from Allwinner.

The seven presentations, described briefly below, are available for download in PDF format by clicking the talk titles below. As usual, Free Electrons has released the presentation slides under a Creative Commons license.

• Buildroot: What’s new?, by Thomas Petazzoni — Summary: Buildroot is a simple, efficient and easy-to-use embedded Linux build system. It can generate a cross-compilation toolchain, a Linux kernel image, bootloader images and more importantly a root filesystem image with many userspace libraries and programs. Based on cross-compilation, Buildroot supports 1200 userspace packages, including GStreamer, X.org, Qt, Gtk, Python, Wayland and more. Used by Google, many SoC vendors, and numerous embedded systems makers, Buildroot is backed by a strong and active open-source community, that publishes stable releases every three months. Since the last talk given at ELC two years ago, Buildroot has grown significantly, gained a lot of popularity and a number of new interesting features have been integrated. Through this talk, we would like to share a little introduction on how to use Buildroot, and then cover the new important features and improvements that have been implemented during the last two years. This talk is intended to be useful both to existing Buildroot users who want to learn more about the latest improvements, and to newcomers who are interested in discovering Buildroot capabilities.

• Using Yocto, for modules manufacturers, by Alexandre Belloni — Summary: Yocto has an alleged steep learning curve. It can be a challenge for modules and evaluation board manufacturers to add support for their devices in Yocto as they don’t necessarily have a software background. This talk will highlight the steps required, techniques and good practices to create a well integrated machine configuration allowing to build images using the Yocto Linux build system. The Crystalfontz support from meta-fsl-arm-extra is used to illustrate the talk.

• Update on boot time reduction techniques, with figures, by Michael Opdenacker — Summary: Many community resources exist about boot time reduction. However, few of them are up to date and share the exact time savings that can be achieved on recent systems. This talk will detail today’s most efficient techniques to reduce boot time. For each of them, figures will be shared, obtained from recent boot time reduction projects and from the preparation of Free Electrons new workshop on this topic. If you attend this talk, you will know which optimization techniques are worth using first, and will save time not exploring techniques that won’t make a significant difference in your project. Don’t tell your boss, and this will leave you more time to contribute to community projects!

• Device Tree for Dummies, by Thomas Petazzoni — Summary: The conversion of the ARM Linux kernel over to the Device Tree as the mechanism to describe the hardware has been a significant change for ARM kernel developers. Nowadays, all developers porting the Linux kernel on new ARM platforms, either new SoCs or new boards, have to work with the Device Tree. Based on practical examples, this talk intends to provide a “getting started guide” for newcomers in the Device Tree world: what is the Device Tree? How is it written and compiled? How do the bootloader and kernel interact? How are Device Tree bindings written and documented? What are the best practices for writing Device Trees and their bindings?

• Two years of ARM SoC support mainlining: Lessons learned, by Thomas Petazzoni — Summary: Throughout the last two years, a team of engineers at Free Electrons has been involved in mainlining the support for several ARM processors from Marvell, converting the not-so-great vendor-specific BSP into mainline quality code progressively merged upstream. This effort of several hundreds working days, has led to the integration of hundreds of patches in the kernel. Through this talk we would like to share some lessons learned regarding this mainlining effort, which could be useful to other engineers involved in ARM SoC support, as well as detail the steps we have gone through, the mistakes we’ve made and how we solved them, and generally our experience on this project.

• SMP bring-up on ARM SoCs, by Gregory Clement — Summary: All the new ARM CPUs are now SMP capable and most of the new ARM SoCs actually use multiple CPUs. Adding SMP support for an SoC means adding specific code very early during the boot process, but also using new APIs, filling the mandatory SMP operations and dealing with new kind of issues. This talk will cover all the aspects: we will see the mandatory parts to add and some parts that are nice to have. Then we will show how to implement them. And finally we will share our experience on the various issues we encountered through real examples.

• Supporting a new ARM platform: The Allwinner SoCs example, by Maxime Ripard — Summary: Since last year, we have been working on supporting the SoCs from Allwinner, a Chinese SoC vendor, in the mainline kernel. These SoCs are cheap, wide-spread, backed by a strong community and, until last year, only supported by an out-of-tree kernel. Through this talk, we would like to share the status of this effort: where we were a year ago, what solutions were in place, where we are currently, and what to expect from the future. We will also focus on the community around these SoCs, the work that is done there, etc.

 
Past and future Embedded Linux Conferences

Now in its 10th year, the Embedded Linux Conference (ELC) is described by the Linux Foundation as “the premier vendor-neutral technical conference for companies and developers using Linux in embedded products.” ELC started out in 2005 as a smaller, more casual affair, launched by Tim Bird and the Consumer Electronics Linux Forum (CELF), which was folded into the Linux Foundation in 2010. In 2011, ELC began a colocation arrangement with the Android Builders Summit. We also checked the Embedded Linux Wayback Machine and located forerunner of the ELC, held in 2000 and called “ELEC,” which stood for Embedded Linux Expo and Conference.

Europe’s version of the ELC, appropriated known as “Embedded Linux Conference Europe” (ELCE), takes place Oct. 13-15 at the Duesseldorf Congress Centre in Duesseldorf, Germany. Further details are available here.

Free Electrons, a specialist in embedded Linux consulting and training services, has created a repository of downloadable presentation videos from embedded Linux, Android, and open-source conferences since 2008. The firm’s videos and presentation materials are generally released under the Creative Commons Attribution-ShareAlike 3.0 license. The PDF slide decks listed above were originally published by Free Electrons, here, and are mirrored by LinuxGizmos with permission.. A photo showing all seven presenters listed above — and indeed, all of the permanent staff of Free Electrons — is available here.