Free “Device Tree 101” webinar, on February 9, 2021

In partnership with ST, we are organizing on February 9, 2021, a free webinar entitled “Device Tree 101”.

The Device Tree has been adopted for the ARM 32-bit Linux kernel support almost a decade ago, and since then, its usage has expanded to many other CPU architectures in Linux, as well as bootloaders such as U-Boot or Barebox. Even though Device Tree is no longer a new mechanism, developers coming into the embedded Linux world often struggle to understand what Device Trees are, what is their syntax, how they interact with the Linux kernel device drivers, what Device Tree bindings are, and more. This webinar will offer a deep dive into the Device Tree, to jump start new developers in using this description language that is now ubiquitous in the vast majority of embedded Linux projects. This webinar will be illustrated with numerous examples applicable to the STM32MP1 MPU platforms, which make extensive usage of the Device Tree.

This webinar will take place on February 9, 2021, and is proposed at two different times during the day: at 10 AM CET (UTC+1) and 5 PM CET (UTC+1). The duration of the webinar is 1 hours and 30 minutes. Registration is free at https://www.eventbrite.com/e/135964923747. The webinar itself will be hosted as a Youtube Live stream, which will allow participants to ask questions in the chat during the webinar.

Device Tree 101

The trainer for this webinar is Thomas Petazzoni, Bootlin’s CTO. Thomas is the author of the popular « Device Tree for Dummies » talk given in 2014 and which helped numerous embedded Linux developers get started with the Device Tree. Thomas has contributed over 900 patches to the official Linux kernel, mainly around ARM hardware platform support. He is also the co-maintainer of the Buildroot open-source project.

Bootlin at FOSDEM 2021: two talks, member of Embedded program committee

FOSDEM21Like all conferences in these times, FOSDEM will take place as an online, virtual event. For all the FOSDEM regular attendees, it will certainly be a very different experience, and for sure, we will all miss the chocolate, waffles, beer, mussels as well as the rainy, muddy, snowy, foggy and cold weather that characterize Brussels in early February. But nevertheless, knowledge sharing and discussions must go on, and FOSDEM will take place! As usual, FOSDEM takes place the first week-end of February, on February 6-7, and the event is completely free, with no registration required.

This time around, Bootlin is once again contributing to FOSDEM:

Make sure to check out the rest of the Embedded Devroom schedule, as well as the overall FOSDEM schedule.

Bootlin toolchains integration in Buildroot

Since 2017, Bootlin is freely providing ready-to-use pre-built cross-compilation toolchains at https://toolchains.bootlin.com/. We are now providing over 150 toolchains, for a wide range of CPU architectures, covering the glibc, uClibc-ng and musl C libraries, with up-to-date gcc, binutils, gdb and C library support.

We recently contributed an improvement to Buildroot that allows those toolchains to very easily be used in Buildroot configurations: the Bootlin toolchains are now all known by Buildroot as existing external toolchains, next to toolchains from other vendors such as ARM, Synopsys and others.

If you are building a Buildroot system for a CPU architecture variant that has a matching toolchain available from bootlin.toolchains.com, then Bootlin toolchains will naturally show up in the Toolchain sub-menu, when the selected Toolchain type is External toolchain. For example, if the selected CPU architecture is ARM little endian Cortex-A9, with VFP you will see:

Bootlin toolchain selection

Once Bootlin toolchains is selected, a new sub-option Bootlin toolchain variant appears, which allows to choose between the different toolchains applicable to the selected CPU architecture:

Bootlin toolchain choice

This hopefully should make Bootlin toolchains easier to use for Buildroot users.

Internally, this support for Bootlin toolchains in Buildroot is generated and updated using the support/scripts/gen-bootlin-toolchains script. In addition to making the toolchains available to the user, it allows generates some Buildroot test cases for each toolchain, so that each of those configuration is tested by Buildroot continuous integration, see support/testing/tests/toolchain/test_external_bootlin.py.

Linux 5.10, Bootlin contributions

Linux 5.10 was released a few weeks ago, and while 5.11-rc2 is already out, it’s still time to look at what Bootlin contributed to the 5.10 kernel. As usual, for a broad overview of the major changes in 5.10, we recommend reading the LWN articles: 5.10 merge window part 1, the rest of the 5.10 merge window, or the 5.10 KernelNewbies page.

Overall, Bootlin contributed 78 patches to this kernel release, in the following areas:

  • Alexandre Belloni did a number of improvements in the support of Microchip ARM platforms: device tree updates, code cleanups, etc.
  • Alexandre Belloni added a new rv3032 RTC driver and did some improvements to the r9701 RTC driver.
  • Miquèl Raynal implemented a significant rework of how ECC engines are handled in the MTD subsystems, so that ECC engines can be used not just for parallel NANDs but also for SPI NANDs. See also the talk that Miquèl gave at the Embedded Linux Conference Europe on this topic: slides and video.
  • Miquèl Raynal contributed a few improvements to the tlv320aic32x4 audio codec driver.
  • Paul Kocialkowski made some small improvements, one in the OV5640 camera sensor driver, and one in the Rockchip DRM driver.
  • Thomas Petazzoni implemented a performance improvement in the max310x driver, used for SPI-connected UART controllers.

In addition to these code contributions, we also contribute by having several of our engineers be maintainers of a few subsystems of the Linux kernel. As part of this:

  • Miquèl Raynal reviewed and merged 47 patches touching the MTD subsystem he co-maintains with other kernel developers.
  • Alexandre Belloni reviewed and merged 42 patches touching either the Microchip ARM or MIPS platforms, or the RTC subsystem.
  • Grégory Clement reviewed and merged 2 patches touching the Marvell ARM/ARM64 platform support.

Here is the complete list of our commits to 5.10.

Bootlin welcomes Thomas Perrot in its team

Welcome on board!Since December 1st, 2020, we’re happy to have in our team an additional engineer, Thomas Perrot, who joined our office in Toulouse, France.

Thomas brings 6+ years of experience working on embedded Linux systems, during which he worked at Intel on Android platforms, and then at Sigfox on the base stations for Sigfox’s radio network. Thomas has experience working with Linux on x86-64, ARM and ARM64 platforms, with a wide range of skills: bootloader development, Linux kernel and driver development, Yocto integration, OTA updates. Thomas was also deeply involved in the strong security aspects of Sigfox base stations, with secure boot and measured boot, TPM, integrity measurement, etc. At Sigfox, Thomas was involved in all steps of the product life-cycle, from the design phase all the way to the in-field deployment, update and maintenance. Last but not least, Thomas is a Linux technologist and a free software enthusiast, who hacks some open source hardware projects on his free time. See also Thomas page on our website and his LinkedIn profile.

Thomas Perrot is joining our growing team of engineers in Toulouse, which already included Paul Kocialkowski, Miquèl Raynal, Köry Maincent, Maxime Chevallier and Thomas Petazzoni.