Announcing buildroot-external-st, Buildroot support for STM32MP1 platforms

STM32MP1 Discovery Kit 2Back in 2019, ST released a brand new processor family, the STM32MP1, whose members are currently based on a dual Cortex-A7 to run Linux combined with one Cortex-M4 to run bare-metal applications, together with a wide range of peripherals.

Following the release of this new platform, Bootlin ported its Embedded Linux and Yocto training courses to be available on STM32MP1, and also published a long series of tutorials showing how to use Buildroot to build an embedded Linux system on STM32MP1: part 1, part 2, part 3, part 4, part 5, part 6 and part 7.

We are happy to announce that we have partnered with ST to develop an improved support of Buildroot on STM32MP1, which is materialized by a Buildroot BR2_EXTERNAL available on Github at https://github.com/bootlin/buildroot-external-st. In Buildroot, a BR2_EXTERNAL is an extension of the core Buildroot, with additional configurations and/or packages.

This BR2_EXTERNAL tree is an extension of Buildroot 2021.02, which provides four example Buildroot configuration to easily get started on STM32MP1 platforms:

  • st_stm32mp157a_dk1, building a basic Linux system for the STM32MP1 Discovery Kit 1 platform, with a minimal Linux root filesystem
  • st_stm32mp157c_dk2, building a basic Linux system for the STM32MP1 Discovery Kit 2 platform, with a minimal Linux root filesystem
  • st_stm32mp157a_dk1_demo, building a much more featureful Linux system for the STM32MP1 Discovery Kit 1 platform, with Linux root filesystem that allows to run Qt5 applications with OpenGL acceleration on the HDMI output, that supports audio, demonstrates the usage of the Cortex-M4, uses OP-TEE, and more.
  • st_stm32mp157c_dk2_demo, building a much more featureful Linux system for the STM32MP1 Discovery Kit 2 platform, with Linux root filesystem that allows to run Qt5 applications with OpenGL acceleration on both the integrated DSI display and HDMI output, that supports audio, WiFi and Bluetooth, demonstrates the usage of the Cortex-M4, uses OP-TEE, and more.

This BR2_EXTERNAL is designed to work with Buildroot 2021.02, with only a small set of modifications, which since then have been integrated in upstream Buildroot, ensuring that STM32MP1 users can directly use upstream Buildroot for their projects.

There is extensive documentation on how to use this BR2_EXTERNAL tree as well as how to test the various features of the STM32MP1 platform: using STM32CubeProgrammer, using Device Tree generated from STM32 CubeMX, using the Cortex-M4, testing display support, using Qt5, using WiFi, using Bluetooth, using audio and using OP-TEE. We have also documented the internals of the BR2_EXTERNAL components.

This Buildroot support is using the latest software components from the recently released 3.1 BSP from ST (see release notes), so it is based on Linux 5.10, U-Boot 2020.10, TF-A 2.4 and OP-TEE 3.12. We will keep this BR2_EXTERNAL updated with newer releases of the ST BSP.

If you face any issue while using this Buildroot support for STM32MP1, you can use the issue tracker of the Github project, or use the ST community forums. Bootlin can also provide commercial support on Linux on STM32MP1 platforms, as well as training courses.

Bootlin eligible to French “Crédit Impôt Recherche” tax incentive

Bootlin CIR agreementA number of years ago, the French tax system has created a tax incentive mechanism called Crédit Impôt Recherche (Research Tax Credit) that allows startups and innovative companies to get tax deductions corresponding to a fraction of their research and development costs. This allows French companies to more easily invest in research and development activities.

In 2021, Bootlin has initiated the process to be eligible to this tax incentive mechanism, and we are happy to announce that after studying Bootlin’s expertise, engineering experience and achievements, the French tax administration has confirmed that Bootlin can deliver research and development activities fulfilling the Crédit Impôt Recherche criteria to its customers. This means that Bootlin customers in France can now integrate the cost of Bootlin engineering services that correspond to research and development activities into their Crédit Impôt Recherche and receive a tax incentive corresponding to up to 30% of the cost of our engineering services.

For our customers outside of France, this tax incentive is obviously not available, but the certification of Bootlin by the French tax administration as a company able to deliver research and development activities is another testimonial of our strong technical expertise in our field of Embedded Linux and Linux kernel development.

Bootlin contributions to Linux 5.14 and 5.15

It’s been a while we haven’t posted about Bootlin contributions to the Linux kernel, and in fact missed both the Linux 5.14 and Linux 5.15 releases, which we will cover in this blog post.

Linux 5.14 was released on August 29, 2021. The usual KernelNewbies.org page and the LWN articles on the merge window (part 1 and part 2) provide the best summaries of the new features and hardware support offered by this release.

Linux 5.15 on the other hand was released on November 1, 2021. Here as well, we have a great KernelNewbies.org article and LWN articles on the merge window (part 1 and part 2).

In total for those two releases, Bootlin contributed 79 commits, in various areas:

  • Alexandre Belloni, as the RTC subsystem maintainer, contributed 9 patches improving various aspects of RTC drivers, the RTC subsystem or Device Tree bindings for RTC
  • Clément Léger contributed a small improvement to the at_xdmac driver used on Microchip ARM platforms
  • Hervé Codina enabled Ethernet support on the old ST Spear320 SoC, by leveraging the existing stmmac Ethernet controller driver
  • Maxime Chevallier fixed a small issue with the Ethernet PHY on the i.MX6 Solidrun system-on-module
  • Miquèl Raynal added support for NV-DDR timings in the MTD susbsystem. This allows to improve performance with NAND flash memories that support those timings. Their usage is specifically implemented in the Arasan NAND controller driver, which Miquèl contributed back in Linux 5.8. See our previous blog post on this topic for more details
  • Miquèl Raynal added support for yet another NAND controller driver, the ARM PL35x, which is used for example on Xilinx Zynq 7000. See our previous blog post on this topic.
  • Miquèl Raynal added support for NAND chips with large pages (larger than 4 KB) to the OMAP GPMC driver.
  • Miquèl Raynal made a few fixes to the IIO driver for the max1027 ADC.
  • Paul Kocialkowski contributed a few patches to enable usage of the Hantro video decoder driver on the Rockchip PX30 processor.
  • Thomas Perrot contributed one patch to enable usage of the Flex Timers on i.MX7, and one to fix an issue in the PL022 SPI controller driver.

And now, as usual the complete list of our contributions to Linux 5.14 and 5.15:

New training course: Real-Time Linux with PREEMPT_RT

In the field of embedded systems, a number of applications need real-time guarantees, and the Linux ecosystem has been offering for a long time a number of solutions to address those needs, either by improving the Linux kernel itself using the PREEMPT_RT approach, or by using a co-kernel approach such as the one offered by Xenomai. Bootlin training’s portfolio already has an initial coverage of these topics in our Embedded Linux system development course.

Today, we are happy to announce a brand new Real-Time Linux with PREEMPT_RT, which is specifically focused on the PREEMPT_RT solution. This solution made a vast amount of progress in recent times in terms of integration into the official Linux kernel, which makes it even more relevant for a number of projects which need real-time guarantees.

The main topics covered by the course are:

  • What is a real-time and deterministic operating system
  • How to configure, build and setup a PREEMPT_RT enabled Linux kernel
  • How to identify and benchmark the hardware platform in terms of real-time characteristics
  • How to configure and tune the Linux kernel and the system for deterministic behavior
  • How to develop and debug real-time user-space Linux applications as well as analyze latencies

The course is illustrated by practical labs or demonstrations made on the BeagleBone Black platform. It has been developed and is taught by Bootlin engineer Maxime Chevallier, who is an experienced embedded Linux and Linux kernel engineer and trainer.

As usual our training materials are fully open-source, including the ones for this brand new session. You can read the Slides and Practical lab instructions. Bootlin is one of the very few companies delivering training courses to make its training materials open-source: by choosing to work with Bootlin for your trainings, you support our work on developing and publishing freely available training materials.

If you’re interested in getting this new Real-Time Linux with PREEMPT_RT training course, you have three options:

  • Public on-line sessions, opened to individual registration. The course lasts 3 sessions of 4 hours. We have scheduled a first session on January 19-21, 2022, and registration is open, for 399 EUR at the Early bird rate, of 449 EUR at the Regular rate.
  • Dedicated on-line sessions, which we organize at the date/time of your choice. The course also lasts 3 sessions of 4 hours. Contact us to request a quote.
  • Dedicated on-site sessions, where our trainer travels to your location to deliver the training course. In this case, the course lasts two full days. Contact us to request a quote.

Bootlin at the SIDO event in Paris, November 10

The SIDO is a large event dedicated to IoT, AI, robotics in Paris, and it takes place next to the Open Source Experience event, which as the name suggest is dedicated to all things related to open-source. For Bootlin whose activity is precisely at the junction between embedded systems/IoT and open-source, being present at this combined event made complete sense.

Therefore, Bootlin CEO Thomas Petazzoni will be present at SIDO on November 10, 2021. If you’re interested in discussing with Bootlin about:

  • Engineering services, and how Bootlin can help you with Embedded Linux development, Linux kernel development and upstreaming, boot time optimization, real-time, Yocto, Buildroot, and anything related to Embedded Linux;
  • Training services, and how Bootlin can help your company, team and engineers grow their skills in the field of Embedded Linux;
  • Career opportunities, both full-time positions and internships

Then feel free to contact us to schedule a meeting!