Thomas Petazzoni – Page 8

Bootlin at Linux Plumbers conference 2022

Next week, almost the entire Bootlin team will be at the Embedded Linux Conference Europe in Dublin, see our previous blog post on this topic. We will give four talks at this event, on a variety of Linux kernel and embedded Linux topics.

During the same week, also in Dublin albeit in a different location, will take place the Linux Plumbers conference. Bootlin engineer Miquèl Raynal will give a talk at Linux Plumbers, as part of the IoTs a 4-Letter Word micro-conference. Miquèl’s talk will discuss Linux IEEE 802.15.4 MLME improvements, as Miquèl has been working for several months on bringing improvements to the 802.15.4 stack in the Linux kernel.

Buildroot Summer 2022 Hackathon

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:

New package for ntpsec, a “a secure, hardened, and improved implementation of Network Time Protocol”
Some cleanup of the genimage configuration files to use shortcuts for common GPT partition GUIDs
Test cases added for the get-developers script
Addition of several new defconfigs for multiple RISC-V 64-bit noMMU platforms: Sipeed MAIX-Bit, Sipeed MAIXDUINO, Sipeed MAIX-Dock, Sipeed MAIX-Go and Canaan KD233, based on Canaan K210 SoC.
Migration of the .py to .pyc byte-compilation to use the built-in Python infrastructure instead of a custom script.
Addition of support for version 12 of the GCC compiler. This means that GCC 11 is now the default in Buildroot, and support for GCC 9 has been removed.
Many new Python packages added: python-lark, python-typeguard, python-mypy-extensions, python-typing-inspect, python-rfc3987, python-ruamel-yaml, python-pyrsistent, python-pylibfdt, python-maturin
Rust has been bumped to 1.62.0
New package for mender-connect, a daemon responsible for handling bidirectional (websocket) communication with the Mender server
Some fixes to the glslsandbox-player package
New package for OpenSC, a set of libraries and utilities to work with smart cards.
New package for hyperfine, a benchmark tool written in Rust. It evaluates execution time of a command passed in arguments and make a relative comparison if multiple arguments are used at the same time.
New package for hawktracer, a highly portable, low-overhead, configurable profiling tool built in Amazon Video for getting performance metrics from low-end devices.
New package for vis-network, a JS library to display dynamic, automatically organised, customizable network views
New package for Avocado, an automated testing suite containing tests for various subsystems.
New package for freeradius-server, an open source server which implements a protocol for remote user Authorization, Authentication and Accounting.
New package for volk, a Vector-Optimized Library of Kernels. It is a library that contains kernels of hand-written SIMD code for different mathematical operations.
A rework of the LTO handling: LTO support is now always enabled in GCC, and the new option BR2_ENABLE_LTO allows to request LTO to be used by packages that support it.
New package for the Qt 6 library, separate from the current Qt 5 package. For now, the Qt 6 package is very minimal: it only packages qt6base, and only the core of Qt, not even the GUI support is enabled. As part of this, the double-conversion and libb2 packages were added.
Support for configurable page size for ARM64 was added. In addition to the default 4 KB, 64 KB pages are supported. This includes some test cases that allow to validate the 64 KB ARM64 page size support in Qemu.
New package for clpeak, a tool that profiles OpenCL devices to find their peak capacities, together with its dependency OpenCL-CLHPP, the C++ bindings for OpenCL
A rework of several top-level menuconfig options: the “enable MMU” option is now part of the Target architecture menu, the Toolchain menu is now before the Build options menu, which allows the choice of the C library to be done before the choice of static vs. shared libraries. This allows the choice of static library to be made unavailable when glibc is selected, fixing a number of invalid configurations.
New package for GDAL, a translator library for raster and vector geospatial data formats.
New package for libutp, a uTorrent Transport Protocol library
New package for dust, an alternative written in Rust of the command “du”.
The C-SKY CPU architecture support was removed, as it was no longer maintained, and barely used.
New package for gitlab-runner, the open source project that is used to run your jobs and send the results back to GitLab
New package for dbus-broker, which is an alternative implementation of the D-Bus daemon, by the systemd community. It is integrated in Buildroot so that either classic D-Bus or dbus-broker can be used as the D-Bus daemon implementation.
New package for nerdctl, a Docker-compatible CLI for containerd, controlling runc.
A rework of how the udev hwdb is handled, to be consistent between systemd and eudev, and to remove useless hwdb source files from the target, as the hwdb is compiled at build time.
And at least 137 packages have seen their version bumped

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.

Linux 5.19 released, Bootlin contributions inside

Linux 5.19 has been released yesterday. We recommend the usual resources of LWN (part 1 and part 2) as well as KernelNewbies to get some high-level overview of the major additions. CNX-Software also has an article focused on the ARM/RISC-V/MIPS improvements.

At Bootlin, we contributed 68 patches to this release, the main highlights being:

Clément Léger contributed patches for the Microchip SAMA5 platform to support suspend operation while running in non-secure mode, with OP-TEE handling the necessary PCSI calls. This is related to our work to port OP-TEE on Microchip SAMA5D2, which we have covered in several blog posts before.
Hervé Codina contributed device Tree updates to enable the PCI controller of the Renesas RZ/N1 platform, which allows to access the USB host controller that sits on an internal PCI bus. Some driver updates for the PCI driver are needed, and they will land in ~~5.20~~6.0 kernel.
Miquèl Raynal contributed several improvements to the IIO subsystem, following his work on several IIO drivers and his related blog post. These improvements either touch the core IIO, or fix some incorrect API use in IIO drivers.
Miquèl Raynal contributed a new driver for the Renesas RZ/N1 DMA router (in drivers/dmaengine) as well as a new driver for the Renesas RZ/N1 Real Time Clock (in drivers/rtc). In addition, Miquèl modified the 8250 UART controller driver to be able to use the DMA capabilities available on the RZ/N1 processor.
Miquèl Raynal also contributed a number of improvements to the IEEE 802.15.4 stack in the Linux kernel.
Paul Kocialkowski contributed support for MIPI CSI-2 in the Allwinner phy-sun6i-mipi-dphy driver.
Paul Kocialkowski and Luca Ceresoli contributed a few misc fixes, touching the SPI core and SPI Rockchip driver and the dmaengine documentation.

The complete details of our contributions are:

Yocto training course updated to Kirkstone release

Back in May 2022, the Yocto Project published the Kirkstone release, the latest Long Term Support version of the popular embedded Linux build system. See the release notes of this 4.0 release.

For many years, Bootlin has helped plenty of engineers around the world get started with the Yocto Project and OpenEmbedded thanks to our Yocto Project and OpenEmbedded development training course, whose training materials are freely accessible, to everyone.

We are happy to announce that we have just published the update of these materials to cover this new Kirstone release. Our practical lab instructions, available for both the STM32MP1 Discovery Kit and the BeagleBoneBlack, have been correspondingly updated:

This update was done by Bootlin engineer Luca Ceresoli, who is teaching this updated version of our course this week. The next public session, open to individual registration, will take place on September 26-30, and will be taught by Maxime Chevallier. If you are interested, you can register directly online. We also offer this course in private sessions, organized on demand for your team, either on-line or on-site, you can contact us for more details.

Embedded Linux Conference Europe 2022: four talks from Bootlin

The schedule for the upcoming Embedded Linux Conference Europe 2022 has been published recently.

Bootlin CEO Thomas Petazzoni is again a member of the program committee for this edition of ELCE, and has helped with other members of this committee in reviewing and selecting the numerous talk submissions that have been received.

Bootlin will obviously be present at this conference. With 13 engineers from Bootlin participating, almost the entire company will be in Dublin for this major event of the embedded Linux community. Also, 4 of the talks that we had submitted have been accepted:

Luca Ceresoli on Basics of I2C on Linux
This talk is an introduction to using I²C on embedded Linux devices. I²C (or I2C) is a simple but flexible electronic bus to allow low-speed communication between the CPU and all sorts of chips: PMICs, ADC/DACs, GPIO expanders, video sensors, audio codecs, EEPROMS, RTCs and many more. It is so popular that knowing it is a must for any embedded system engineer. Luca will first give an introduction to what I2C is at the electrical level. He will then describe how I2C is implemented in the Linux kernel driver model and how that appears in sysfs, how to describe I2C devices using device tree and how to write a driver for an I2C device. Finally he will present the tools to communicate with the chips from userspace and share some debugging techniques, including inspection of the physical bus and software-level debugging.
Miquèl Raynal on Improving Wireless PAN Support
Anybody eager to learn about IoT devices has at least once tried to play with Zigbee or 6lowpan sensors. These two protocols are built on top of a well common MAC/PHY specification: IEEE 802.15.4, also known as Wireless Personal Area Networks: WPAN, designed to be low-rate/low-range wireless networks. There is already substantial support for this protocol in the Linux kernel but when my journey started, several of the MAC-related operations well described in the specification were not implemented, making the subsystem mainly useful for very simple use cases: peer-to-peer transmissions. This is unfortunate as a significant part of the idea behind WPAN is to make these networks quite adaptive and resilient, which requires a minimal subset of the peer management procedure to be supported. Besides a number of preparation changes, the main idea behind the continuous flow of patches was to bring support for the scanning procedure which allows a PAN controller to detect all the compatible devices around it in different ways. Discovering these devices is the first step in order to associate them together and build up starred networks. This talk will be an opportunity to explain the new APIs allowing such discoveries and provide a state of the art of the support in the mainline kernel.
Michael Opdenacker on Implementing A/B System Updates with U-Boot
A popular way to implement system updates is through the A/B scheme, in which you have two copies of the root filesystem, one which is active, and one that is meant to contain the next update. When a new update is successfully applied, you need to make the corresponding partition become the new active one. That’s when a number of practical questions arise, such as how to identify the active partition, how to detect when the new system fails to boot properly, and how to fall back to the previous version? It was hard to find documentation about how U-Boot could address such needs to implement a functional and failsafe A/B system update mechanism. This presentation proposes to address this need by sharing the practical solutions we found, using lesser known commands and capabilities in U-Boot. We will also explain how the Linux side can cooperate with the U-Boot side. Fortunately, you won’t need to erase half of your brain to get updated on this topic.
Paul Kocialkowski on Walking Through the Linux-Based Graphics Stack
The graphics stack used with the Linux kernel is a notoriously complex beast. From userspace down to the kernel level, a number of components are involved and interact with eachother. It is also an area that is constantly evolving to meet new use cases, refresh legacy implementations and achieve better performance. This makes it difficult to have a clear idea of the big picture and what is actually happening when using graphics-related components. This presentation will detail a walk through the graphics stack, with actual examples of displaying a buffer and rendering using the GPU. Going from the application level through the system libraries, down to the kernel and ending with actual hardware configuration. State-of-the-art technologies such as Wayland and DRM will be highlighted with relevant excerpts from the source code of related free software projects that are widely used today.

We look forward to meeting again the embedded Linux community, its developers, users and maintainers, at Dublin during this conference!

Updated Buildroot support for STM32MP1 platforms

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:

Updated to work with Buildroot 2022.02, the current LTS version of Buildroot
Updated to use the 4.0 “ecosystem” from ST, which means we’re using updated BSP components from ST, namely Linux 5.15, U-Boot 2021.10, TF-A 2.6 and OP-TEE 3.16
New defconfigs have been added to support all variants of the STM32MP157 Discovery Kits: STM32MP157A-DK1 and STM32MP157D-DK1, as well as STM32MP157C-DK2 and STM32MP157F-DK2.
The minimal defconfigs now use OP-TEE as BL32 instead of the minimal monitor provided by TF-A, called SP-MIN
The minimal defconfigs now have mdev enabled, to benefit from automatic kernel module loading
The demo defconfigs now have the Dropbear SSH server enabled

The document available on the Github page details how to use this work, but here is a quick start in just a few steps:

Retrieve Buildroot itself, a branch containing a few patches on top of upstream 2022.02 is needed
$ git clone -b st/2022.02 https://github.com/bootlin/buildroot.git
Retrieve buildroot-external-st
$ git clone -b st/2022.02 https://github.com/bootlin/buildroot-external-st.git
Go into the Buildroot directory
$ cd buildroot/
Configure Buildroot, for example here the demo configuration for the STM32MP157F-DK2
$ make BR2_EXTERNAL=../buildroot-external-st st_stm32mp157f_dk2_demo_defconfig
Run the build
$ make
Flash the resulting SD card image available at output/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.

Linux 5.18 released, Bootlin contributions inside

Linux 5.18 has been released a bit over a week ago. As usual, we recommend the resources provided by LWN.net (part 1 and part 2) and KernelNewbies.org to get an overall view of the major features and improvements of this Linux kernel release.

Bootlin engineers have collectively contributed 80 patches to this Linux kernel release, making us the 28th contributing company according to these statistics.

Alexandre Belloni, as the RTC subsystem maintainer, continued to improve the overall subsystem, and migrate drivers to new features and mechanisms introduced in the core RTC subsystem
Clément Léger contributed a new RTC driver that allows to use the RTC exposed by the OP-TEE Trusted Execution Environment, as well as a few other fixes
Hervé Codina and Luca Ceresoli contributed some fixes: Hervé to the dw-edma dmaengine driver, and Luca to the Rockchip RK3308 pinctrl driver
Miquèl Raynal, as the MTD subsystem co-maintainer, contributed the remainder of his work to generalize the support of ECC handling, and allow both parallel and SPI NAND to use either software ECC, on-die ECC, or ECC done by a dedicated controller. Included in this work is a new driver for the Macronix external ECC engine, in drivers/mtd/nand/ecc-mxic.c
Miquèl Raynal also made a few contributions to the 802.15.4 part of the networking stack, and we have more contributions in this area coming up.
Paul Kocialkowski contributed a small fix to Allwinner Device Tree files, and another attempt at fixing an issue with the display panel detection/probing in the DRM subsystem

Bootlin at Live Embedded Event, 3rd edition

Tomorrow, on May 18, the third edition of Live Embedded Event will take place. Live Embedded Event is a free and fully online conference, dedicated to embedded topics at large. One can register directly online to receive a link to attend the conference.

Bootlin will be participating to this third edition, with 3 talks from 3 different Bootlin engineers:

Michael Opdenacker on LLVM tools for the Linux kernel, at 12:00 UTC+2 in Track 3. Details: Recent versions of Linux can be compiled with LLVM’s Clang C language compiler, in addition to Gcc, at least on today’s most popular CPU architectures. This presentation will show you how. Cross-compiling works differently with Clang: no architecture-specific cross-compiling toolchain is required. We will compare the Clang and Gcc compiled kernels, in terms of size and boot time. More generally, we will discuss the concrete benefits brought by being able to compile the kernel with this alternative compiler, in particular the LLVM specific kernel Makefile targets: clang-tidy and clang-analyzer.
Grégory Clement on AMP on Cortex A9 with Linux and OpenAMP, at 15:30 UTC+2 in Track 2. Details: While, usually, the Cortex A9 cores are used in SMP, one could want use one of the core to run an other OS. In this case the system becomes AMP. Typically, it allows running a dedicated real time OS on a core. This presentation will show the step that allow having this support using open sources stacks. First we will see what OpenAMP is, then how the Linux kernel can communicate with external OS using remote proc message, and finally what to adapt in the Linux kernel and OpenAMP in order to support the usage of a Cortex A9. This was experimented on an i.MX6 but the solution presented has the advantage to be easily adapted on any SoC using Cortex A9.
Thomas Perrot on PKCS#11 with OP-TEE at 15:00 UTC+2 in Track 2. Details:
PKCS#11 is a standard API that allows to manage cryptographic tokens, regardless of the platform such as Hardware Security Modules, Trusted Plaform Modules or smart cards. Moreover, modern processors offer a secure area, named Trusted Execution Environment (TEE) that allows the isolation of some operations, datas and devices to guarantee their integrity and confidentiality. OP-TEE is an open source implementation of Trusted Execution Environment that runs in parallel with the operating system, as a companion. In this talk, we will first introduce PKCS#11, then OP-TEE, and finally look at how PKCS#11 operations can be performed through OP-TEE, and what are the benefits. Our presentation will be illustrated with examples based on the NXP i.MX8QXP platform, but should be applicable to other platforms that have OP-TEE support.

Join us at Live Embedded Event, and discover our talks as well as the many other talks from other speakers!

Bootlin at Embedded Recipes and Kernel Recipes 2022, Paris

After 2 editions cancelled due to the pandemic, the famous Embedded Recipes and Kernel Recipes conferences are back: they will take place end of May and beginning of June in Paris!

Bootlin will be present at this event, with several engineers from the team participating:

Paul Kocialkowski and Michael Opdenacker will be attending both Embedded and Kernel Recipes
Kamel Bouhara will be attending Embedded Recipes
Grégory Clement will be attending Kernel Recipes

We look forward to meeting you at this event! If you want to discuss business or career opportunities with Bootlin, do not hesitate to meet Paul, Michael, Kamel or Grégory during Embedded and/or Kernel Recipes!

Bootlin at the Embedded Linux Conference North America 2022

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 Petazzoni will give a talk Buildroot: what’s new?, providing an update on the improvements and new features in the Buildroot build system that have been integrated over the past two years
Alexandre Belloni will give a talk Yocto Project Autobuilders and the SWAT Team, during which he will explain what’s happening behind in the scenes in the Yocto Project to review and validate contributions before they are integrated.

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.