We are happy to announce a new release of our buildroot-external-st project, which is a Buildrooot add-on that allows to easily get started with STMicroelectronics STM32MP platforms using Buildroot. This new release openstlinux-6.1-buildroot-2024.02.3-mpu-v24.06.26 brings support for the new STM32MP2 platform, updated ST BSP components, updated Buildroot.
Continue reading “Buildroot support for STM32MP updated, STM32MP2 added”
We continue the support of the buildroot-external-st project as presented in our first announce, which is an extension of the Buildroot build system with ready-to-use configurations for the STMicroelectronics STM32MP1 platforms. We already published several updates of this support, with the LTS 2022.02 and version 4.0 of ST BSP version update and the LTS 2022.02.7 and version 4.1 of ST BSP version update.
More specifically, this project is a BR2_EXTERNAL repository for Buildroot, with a number of defconfigs that allow to quickly build embedded Linux systems for the STM32MP1 Discovery Kit platforms. It’s a great way to get started with Buildroot on those platforms.
Today, we are happy to announce an updated version of this project, published under the branch st/2023.02.10 at https://github.com/bootlin/buildroot-external-st. This new version brings a number of additional features:
Continue reading “Updated Buildroot support for STM32MP1 platforms, ST BSP v5.0”
Systemd is a popular init system, used to bootstrap user space and manage user processes. It now replaces several Linux utilities with its own components like log management, networking, time management, etc. There is even a bootloader component now. Systemd is obviously ubiquitous nowadays for desktop/server Linux distributions, and is also commonly used on embedded devices to benefit from features such as parallel startup of services, monitoring of services, and more.
In a recent project that uses Buildroot as its build system, we have used systemd with the storage consisting of a read-only root filesystem (SquashFS) and an overlay file system (OverlayFS) mounted on /etc. While doing this, we faced two issues with the use of OverlayFS on /etc:
/run and wait to have read-write access to create it (see more details). In that case, the machine-id file is re-generated at each boot (because /run is a tmpfs, which means that the machine identification changes at each boot, which is not necessarily desirable. On the other hand, we don’t want to machine-id file to be part of the SquashFS filesystem because the SquashFS filesystem is identical on all devices, while the /etc/machine-id file is unique per device. So ideally, we would like this machine-id file to be stored in our OverlayFS, generated during the first boot. The issue is that reading the machine-id file is done very early by systemd, before we get the chance to mount the OverlayFS./etc/fstab and any other services is started after such parsing, which is too late. We could think of running daemon-reload from a custom service once mounting was complete, but this is not really a stable solution, asThe solution suggested by Lennart, and elsewhere on the wider Internet is to mount the OverlayFS from an initramfs, which allows to have it setup before systemd even starts. As we use Buildroot and using an initramfs adds complexity by requiring a separate configuration to manage multiple images. This was overkill in our case, just for setting up the overlay. The solution we eventually chose was to create an init_overlay.sh script which is started as init before systemd, by adding init=/sbin/init_overlay.sh to the kernel command line:
#!/bin/sh mount -t proc -o nosuid,nodev,noexec none /proc mount -t sysfs -o nosuid,nodev,noexec none /sys mount /dev/mmcblk0p2 /mnt/data mount -t overlay overlay -o lowerdir=/etc,upperdir=/mnt/data/etc,workdir=/mnt/data/.etc-work /etc exec /sbin/init
Hopefully, this will be useful to others. Of course, we’re also curious to hear if others faced the same issue, and discover how they solved this. Let us know in the comments.
With the FOSDEM conference taking place on-site again after 2 years of virtual conference, this month of February also saw the return of the traditional Buildroot Developers Meeting from the Buildroot project.
This meeting is traditionnally held twice a year, around FOSDEM and around the Embedded Linux Conference Europe, and allows maintainers and contributors to the Buildroot project to gather for a few days and make progress on various tasks/topics.
This year, the post-FOSDEM Buildroot Developers Meeting took place on February 6, 7 and 8 in Brussels, and was hosted at the Smile offices, who kindly sponsored the location for the meeting.
Continue reading “Report from the Buildroot Developers Meeting at FOSDEM 2023”
Back in December 2021, we announced the buildroot-external-st project, which is an extension of the Buildroot build system with ready-to-use configurations for the STMicroelectronics STM32MP1 platforms. Later on, in July 2022, we updated it to the lastest Buildroot LTS 2022.02 and version 4.0 of ST BSP version.
More specifically, this project is a BR2_EXTERNAL repository for Buildroot, with a number of defconfigs that allow to quickly build embedded Linux systems for the STM32MP1 Discovery Kit platforms. It’s a great way to get started with Buildroot on those platforms.
Today, we are happy to announce an updated version of this project, published under the branch st/2022.02.7 at https://github.com/bootlin/buildroot-external-st. This new version brings the following changes:
Continue reading “Updated Buildroot support for STM32MP1 platforms, ST BSP v4.1”
Buildroot is an easy-to-use and popular embedded Linux build system, used by many as an alternative to Yocto/OpenEmbedded. Bootlin has expertise in both build systems, and has in particular been a long time contributor to the Buildroot project. Bootlin CEO’s Thomas Petazzoni is one of the co-maintainers of the project, to which he has contributed over 5000 patches.
From July 23 to July 27, four members of the Buildroot community gathered in the sunny south of France for a 5-day long hackathon on Buildroot: Yann Morin, Romain Naour from Smile, Arnout Vandecappelle from Mind and Thomas Petazzoni from Bootlin.
The main goal of this hackathon was to reduce the backlog of patches accumulated in the project’s patchwork, the tool used in the Buildroot community to record all contributed patches and make sure all of them are handled: reviewed, accepted, or potentially rejected.
When we started the hackathon, the backlog of patches cumulated to over 410 patches, and the hackathon allowed to reduce the backlog to 150-160 patches, especially taking care of all patches contributed before the beginning of 2022. In total, over 400 patches were merged during the hackathon in the Buildroot Git repository, which obviously is more than the reduction of the backlog of patches. This is mainly due to additional patches contributed during the hackathon itself (the community has been very active at submitting new patches!) and due to the review process triggering additional ideas or rework that required more patches.
Here is a summary of the main highlights that were merged during this hackathon:
.py to .pyc byte-compilation to use the built-in Python infrastructure instead of a custom script.BR2_ENABLE_LTO allows to request LTO to be used by packages that support it.Several other topics were looked at and discussed, but did not necessarily lead to patches already integrated. One such topic is the investigation of several issues with elf2flt, the tool used on noMMU architectures to produce binaries in the FLAT format, from an ELF binary. Another topic is the merge of the SciPy package, for which the review and testing is well advanced.
Overall, it was a very productive hackathon, and besides the massive work done on Buildroot from 9 AM to (at least) midnight each day, the participants also enjoyed lots of side discussions, embedded Linux related or not. We look forward to the next in-person gathering of the Buildroot community, on September 17/18 in Dublin, right after the Embedded Linux Conference Europe.
Back in December 2021, we had announced the buildroot-external-st project, which is an extension of the Buildroot build system with ready-to-use configurations for the STMicroelectronics STM32MP1 platforms.
More specifically, this project is a BR2_EXTERNAL repository for Buildroot, with a number of defconfigs that allows to quickly build embedded Linux systems for the STM32MP1 Discovery Kit platforms. It’s a great way to get started with Buildroot on those platforms.
Today, we are happy to announce an updated version of this project, published under the branch st/2022.02 at https://github.com/bootlin/buildroot-external-st. This new version brings the following changes:
The document available on the Github page details how to use this work, but here is a quick start in just a few steps:
$ git clone -b st/2022.02 https://github.com/bootlin/buildroot.git$ git clone -b st/2022.02 https://github.com/bootlin/buildroot-external-st.git$ cd buildroot/$ make BR2_EXTERNAL=../buildroot-external-st st_stm32mp157f_dk2_demo_defconfig$ makeoutput/images/sdcard.img and boot your board!If you have any question or issue, feel free to use the Github issue tracker to contact us. Bootlin is an ST Authorized Partner, and can provide engineering and training services around embedded Linux on STM32MP1 platforms.
Bootlin CEO Thomas Petazzoni and COO Alexandre Belloni will both be attending the next Embedded Linux Conference North America, on June 21-24 in Austin, Texas.
In addition, both Thomas and Alexandre will be speaking at the event:
Thomas and Alexandre will also naturally be available during the event to discuss business or career opportunities, so do not hesitate to get in touch if you’re interested.
Finally, prior to the event, Thomas Petazzoni will be in the Bay Area on June 13-15, also available for meetings or discussions.
Back 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 filesystemst_stm32mp157c_dk2, building a basic Linux system for the STM32MP1 Discovery Kit 2 platform, with a minimal Linux root filesystemst_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.
The schedule for the Embedded Linux Conference 2021 has been published and features 4 talks proposed by Bootlin !
This year, the ELC will take place in Seatle but will be organised as a hybrid virtual/physical event due to the pandemic. As usual the ELC will have a really interesting schedule with 46 talks covering a wide range of topics: build system, kernel graphics, boot process, security, etc.
See below the details of Bootlin talks that will be presented as virtual talks.
Capturing pixels with a camera involves a number of steps, from the ADC reading the photosites in the image sensor to the final pixel values that are ready for encode/display, with various processing and transmission taking place along the way. While simple cases put most of the heavy lifting on the image sensor’s side (through its embedded processor) and use a simple parallel bus for transmission, advanced cases require more work to be done outside of the sensor. In addition, modern high-speed transmission buses also bring-in more complexity. This talk will present how support for such an advanced use case was integrated into the mainline Linux kernel, using the Media and V4L2 APIs. It involves supporting a sensor using the raw Bayer RGB format, transmission over the MIPI CSI-2 bus as well as support for the Image Signal Processor (ISP) found on Allwinner platforms. A specific focus will be set on this ISP, with details about the features it implements as well as the internal and userspace APIs that are used to support it. The integration between all of the involved components will also be highlighted.
Talk given by Paul Kocialkowski, at 4:50 PM PDT on September 27, 2021. See this talk in the schedule.
To this date, Buildroot supports more than 2,500 packages, selected for the ability to run them on embedded Linux systems. We’ve gone exploring this Eldorado, and came back with multiple nuggets of all shapes and colors. Join this playful presentation and as if you were still a new comer to the embedded Linux community, discover lesser known tools and resources that can add to the functionality of your systems or make your life as a developer easier and more fun. Whenever possible, each resource will be shown through a quick demonstration or video capture. During this talk, I’ll also open an Etherpad for all participants to share their favorite solutions with the rest of the audience, especially the ones that deserve to be better known, and could be worth supporting in Buildroot too. We will close the session by an open review and discussion based on the nuggets shared by the audience.
Talk given by Michael Opdenacker, at 12:00 PM PDT on September 28, 2021. See this talk in the schedule.
I3C is the new bus specification by the MIPI Alliance. While being compatible with I2C devices, this bus brings a colorful set of new features such as dynamic address assignment, in-band interrupts, hot-join, master handover and many others. It was improved once again recently with the 1.1 version of the specification which brought timer based sampling synchronization and targeted reset. All this make the I3C bus a good candidate for a number of new situations compared to its I2C cousin. It is then more and more being included in new hardware designs. With this talk we would like to propose a reminder of the various components and concepts of this relatively new bus. We will then detail how it is implemented in the Linux kernel with a short guided tour in the I3C core. Since the previous talk on I3C in 2018 by Boris Brezillon, I3C has now become a reality and starts to become available in real hardware designs. This talk will recap the basics of I3C as well as add details of the 1.1 specification and improvements in the Linux support.
Talk given by Miquèl Raynal, at 4:00 PM PDT on September 28, 2021. See this talk in the schedule.
Talk given by Clément Léger, at 12:00 PM PDT on September 29, 2021. See this talk in the schedule.
