Linux 5.6, Bootlin contributions inside

Linux 5.6 was released last Sunday. As usual, LWN has the best coverage of the new features merged in this release: part 1 and part 2. Sadly, the corresponding KernelNewbies page has not yet been updated with the usual very interesting summary of the important changes.

Bootlin contributed a total of 95 patches to this release, which makes us the 27th contributing company by number of commits, according to the statistics. The main highlights of our contributions are:

  • Our work on supporting hardware-offloading of MACsec encryption/decryption in the networking subsystem and support for this offloading for some Microchip/Vitesse PHYs has been merged. See our previous blog post for more details about this work done by Bootlin engineer Antoine Ténart
  • As part of our work on the Rockchip PX30 system-on-chip, we contributed support for LVDS display on Rockchip PX30, and support for the Satoz SAT050AT40H12R2 panel. This work was done by Miquèl Raynal
  • Alexandre Belloni as the RTC maintainer did his usual number of cleanup and improvements to existing RTC drivers
  • We did a number of small contributions to the Microchip AT91/SAMA5 platform: support for the Smartkiz platform from Overkiz, phylink improvements in the macb driver, etc.
  • Paul Kocialkowski improved the Intel GMA 500 DRM driver to support page flip.
  • Paul Kocialkowski contributed support for the Xylon LogiCVC GPIO controller, which is a preliminary step to contributing the Xylon LogiCVC display controller support. See our blog post on this topic.

In addition to being contributors, a number of Bootlin engineers are also maintainers of various parts of the Linux kernel, and as such:

  • Alexandre Belloni, as the RTC subsystem maintainer and Microchip platforms co-maintainer, has reviewed and merged 55 patches from other contributors
  • Miquèl Raynal, as the MTD co-maintainer, has reviewed and merged 21 patches from other contributors
  • Grégory Clement, as the Marvell EBU platform co-maintainer, has reviewed and merged 12 patches from other contributors

Here is the detail of all our contributions:

Covid-19: Bootlin proposes online sessions for all its courses

Tux working on embedded Linux on a couchLike most of us, due to the Covid-19 epidemic, you may be forced to work from home. To take advantage from this time confined at home, we are now proposing all our training courses as online seminars. You can then benefit from the contents and quality of Bootlin training sessions, without leaving the comfort and safety of your home. During our online seminars, our instructors will alternate between presentations and practical demonstrations, executing the instructions of our practical labs.

At any time, participants will be able to ask questions.

We can propose such remote training both through public online sessions, open to individual registration, as well as dedicated online sessions, for participants from the same company.

Public online sessions

We’re trying to propose time slots that should be manageable from Europe, Middle East, Africa and at least for the East Coast of North America. All such sessions will be taught in English. As usual with all our sessions, all our training materials (lectures and lab instructions) are freely available from the pages describing our courses.

Our Embedded Linux and Linux kernel courses are delivered over 7 half days of 4 hours each, while our Yocto Project, Buildroot and Linux Graphics courses are delivered over 4 half days of 4 hours each.

Here are all the available sessions. If the situation lasts longer, we will create new sessions as needed:

Type Dates Time Duration Expected trainer Cost and registration
Embedded Linux (agenda) Apr. 7, 8, 14, 15, 16, 20, 21 14:00 -18:00 (Paris time) 28 h Michael Opdenacker 1090 EUR + VAT* + fees
Linux kernel (agenda) Apr. 6, 7, 9, 14, 20, 21, 23 14:00 – 18:00 (Paris time) 28 h Grégory Clement 1090 EUR + VAT* + fees
Yocto Project (agenda) Apr. 8, 10, 15, 17 14:00 – 18:00 (Paris time) 16 h Alexandre Belloni 790 EUR + VAT* + fees
Buildroot (agenda) Apr. 15, 17, 20, 22 14:00 – 18:00 (Paris time) 16 h Thomas Petazzoni 790 EUR + VAT* + fees
Linux Graphics (agenda) Apr. 21, 23, 27, 29 14:00 – 18:00 (Paris time) 16 h Paul Kocialkowski 790 EUR + VAT* + fees

* VAT: we should be able to grant VAT refunds for participants who are registered by businesses, provided we are given all the details we need for VAT exemption.

Each public session will be confirmed once there are at least 5 participants. If the minimum number of participants is not reached, Bootlin will propose new dates or a full refund (including Eventbrite fees) if no new date works for the participant.

We guarantee that the maximum number of participants will be 12.

Dedicated online sessions

If you have enough people to train, such dedicated sessions can be a worthy alternative to public ones:

  • Flexible dates and daily durations, corresponding to the availability of your teams.
  • Confidentiality: freedom to ask questions that are related to your company’s projects and plans.
  • If time left, possibility to have knowledge sharing time with the instructor, that could go beyond the scope of the training course.
  • Language: possibility to have a session in French instead of in English.

Online seminar details

Each session will be given through Zoom. Each participant should have her or his own connection and computer (with webcam and microphone) and if possible headsets, to avoid echo issues between audio input and output. This is probably the best solution to allow each participant to ask questions and write comments in the chat window. We also support people connecting from the same conference room with suitable equipment.

One hour before the session starts, we will organize a test connection, to make sure that everyone has a working set up.

How to register

For online public sessions, use the EventBrite links in the above list of sessions to register one or several individuals.

To register an entire group (for dedicated sessions), please contact and tell us the type of session you are interested in. We will then send you a registration form to collect all the details we need to send you a quote.

You can also ask all your questions by calling +33 484 258 097.

Questions and answers

Q: Why just demos instead of practicing with real hardware?
A: Shipping real hardware is going to be complicated to organize in the next weeks, and we are not fully ready to support people doing practical labs remotely with real hardware either. Hence, what we we’re proposing is to replace practical labs with practical demonstrations shown by the instructor. The instructor will go through the normal practical labs with the standard hardware that we’re using.

Q: Why proposing half days instead of full days?
A: From our experience, it’s very difficult to stay focused on a new technical topic for an entire day without having periodic moments when you are active (which happens in our public and on-site sessions, in which we interleave lectures and practical labs). Hence, we believe that daily slots of 4 hours (with 2 or 3 small breaks) is a good solution, also leaving extra time for following up your normal work or taking care of your relatives at home.

Linux 5.5 released, Bootlin contributions inside

Linux 5.5 was recently released, as usual bringing a large number of new features and improvements, which are nicely detailed in the LWN articles on merge window part 1 and merge window part 2, but also on the Kernelnewbies wiki.

According to the statistics, a total of 14350 changes were made to this kernel release, to which Bootlin contributed 124 patches, making us the 19th contributing company by number of commits. Here are the highlights of our contributions:

  • By far and large our most important achievement in Linux 5.5 is the merge of the H265 decoding support in the Allwinner VPU driver, developed by Paul Kocialkowski. This was the last missing feature to complete the effort funded by the Kickstarter campaign we launched in February 2018. See our blog post wrapping up the Allwinner VPU work.
  • Alexandre Belloni as the RTC subsystem maintainer, as usual contributed a large number of RTC driver improvements and fixes.
  • Antoine Ténart contributed some improvements to the Cadence MACB driver, most notably used as the Ethernet controller driver on Microchip/Atmel platforms. The main improvement is the conversion to the phylink subsystem for the interaction with the Ethernet PHY.
  • Grégory Clement contributed numerous enhancements to the Microchip/Atmel SPI controller driver, mainly aimed at fixing and improving the support for Chip Select, both native Chip Selects and GPIO-based Chip Selects.
  • Kamel Bouhara contributed a few additional Device Tree files to describe home automation hardware platforms from Overkiz, based on the Microchip SAMA5D2 processor, as well as an improvement to a Microchip SoC driver that allows to expose the platform serial number to user-space.
  • Miquèl Raynal added support for a new Marvell system-on-chip called Marvell CN9130. Despite the name, this chip is from a hardware point of view in the same family as the Marvell Armada 7K and 8K, which were already supported upstream.
  • Miquèl Raynal contributed a number of fixes and improvements to the Macronix SPI controller driver.
  • Miquèl Raynal added support for the ADC converters over SPI MAX1227, MAX1229 and MAX1231 to the existing max1027 IIO driver in the kernel. These ADCs have a 12-bit resolution.
  • Miquèl Raynal improved the SPI controller driver for the Zynq system-on-chips to correctly support multiple Chip Selects.

In addition to these direct contributions, some of the Bootlin engineers are also Linux kernel maintainers and therefore review and merge patches from other contributors: Alexandre Belloni as the RTC subsystem maintainer and Microchip platform co-maintainer reviewed and merged 45 patches from other contributors, Miquèl Raynal as the MTD subsystem co-maintainer reviewed and merged 39 patches from other contributors and Grégory Clement as the Marvell platform co-maintainer reviewed and merged 29 patches from other contributors.

Here is the detail of our contributions:

Linux 5.4 released, Bootlin contributions inside

LinuxThis time around, we’re quite late to the party, but Linux 5.4 was indeed released a number of weeks ago, and once again, Bootlin contributed a number of patches to this Linux kernel release. As usual, the most useful source of information to learn about the major features brought by Linux 5.4 are the LWN articles (part 1, part 2) and the KernelNewbies Wiki.

With a total of 143 patches contributed to this release, Bootlin is the 17th contributing company by number of commits acccording to the Linux Kernel Patch Statistic.

Here are the highlights of our contributions:

  • Antoine Ténart contributed support for IEEE 1588 Precision Time Protocol (PTP) to the Microsemi Ocelot Ethernet switch driver, which Bootlin developed and upstreamed in 2018 (see our blog post)
  • In the MTD subsystem, a number of contributions to the spi-nor support, written originally by Boris Brezillon, made their way upstream.
  • In the support of Microchip (formerly Atmel) platforms, Kamel Bouhara, who joined Bootlin in September 2019, sees his first kernel contribution merged as a Bootlin engineer: dropping useless support for platform_data from the Atmel PWM driver.
  • In the support of Allwinner platforms
    • Maxime Ripard contributed a brand new driver for the Allwinner A10 camera interface driver, a driver that we started at Bootlin for the CHIP platform back in the days, and that we finished more recently.
    • Maxime Ripard contributed a significant number of improvements to the sun4i-i2s audio interface driver, especially TDM support, which was developed as part of a customer project at Bootlin.
    • Maxime Ripard also contributed numerous enhancements to Allwinner platform Device Tree files, especially in the area of using YAML schemas.
  • In the support for Marvell platforms
    • Grégory Clement added cpufreq support to the Marvell Armada 7K/8K platform by extending some of its clock drivers.
    • Miquèl Raynal contributed improvements to the Marvell CP110 COMPHY driver, which is used to control SERDES lanes on the Marvell Armada 7K/8K platforms, and added the description of the SERDES lanes used by various IP blocks in those processors.
  • Alexandre Belloni, as the RTC subsystem maintainer, did a number of fixes and improvements in several RTC drivers (mainly pcf2123 and pcf8563)
  • For the LPC3250 platform, for which Bootlin delivered a modern BSP to a customer last year, Alexandre Belloni fixed an issue in the lpc_eth network driver, which was preventing the system from booting if the network had been initialized by the bootloader.

In addition to being contributors, some Bootlin engineers are also maintainers of various parts of the Linux kernel, and as such review and merge code from other contributors:

  • As the RTC subsystem maintainer and Microchip platform co-maintainer, Alexandre Belloni merged 47 patches from other contributors
  • As the MTD subsystem co-maintainer, Miquèl Raynal merged 33 patches from other contributors
  • As the Marvell platform co-maintainer, Grégory Clement merged 11 patches from other contributors

Here are the details of all our contributions to Linux 5.4:

Linux 5.3 released, Bootlin contributions inside

Penguin from Mylène Josserand
Drawing from Mylène Josserand, based on a picture from Samuel Blanc (
The 5.3 version of the Linux kernel was released recently. As usual, we recommend our readers to look at the LWN coverage for this release merge window: part 1 and part 2. Together with the KernelNewbies page, these articles give a very nice overview of the major features and improvements of this new release.

For this release, Bootlin is the 16th contributing company by number of commits, with 143 patches merged in the Linux kernel. Our significant contributions this time were:

  • Support for Allwinner processors
    • The support for H264 video decoding, from Maxime Ripard, was finally merged in the cedrus VPU driver that we have developed thanks to the funding of our Kickstarter campaign last year. The last missing piece is H265 video decoding, which we have submitted several times and we hope to get merged soon.
  • Support for Marvell platforms
    • Antoine Ténart contributed a number of bug fixes and updates to the inside-secure crypto driver, which is used for the cryptographic hardware accelerator found on Marvell Armada 3700 and Marvell Armada 7K/8K.
    • Maxime Chevallier contributed many improvements to the mvpp2 network driver, used on the Marvell Armada 375 and Armada 7K/8K systems. His patches improve the traffic classification offloading capabilities, a topic he will present in detail at the next Embedded Linux Conference Europe.
    • Miquèl Raynal added PHY support for the PCIe Armada 8K driver, and adjusted a few things in the Marvell Armada 7K/8K Device Tree files.
  • Support for Microchip MPU (formerly Atmel) platforms
    • Alexandre Belloni converted the remaining SoCs (SAM9x5, SAM9G45, SAM9RL and SAMA5D3) to the new slow clock controller bindings.
    • Antoine Ténart contributed a few small improvements to the macb driver, for the Cadence network controller used on Microchip platforms.
  • Maxime Ripard contributed numerous YAML Device Tree schemas, to help the effort of converting many Device Tree bindings to the new YAML format, which can be used to validate Device Trees against their bindings.
  • Maxime Ripard contributed numerous patches to the core DRM subsystem: a complete rewrite of the command line parser that parses the DRM-related options of the kernel command line, and support for new options. This was done as part of an effort to make sure the upstream Linux kernel can support all the possible options that the downstream RaspberryPi kernel+firmware combination provides to configure the display.
  • Paul Kocialkowski contributed a few improvements to the RaspberryPi vc4 display controller driver, related to buffer allocation.

Also, several of Bootlin engineers are also kernel maintainers, so they review and merge patches from other contributors:

  • Miquèl Raynal as the NAND subsystem maintainer and MTD subsystem co-maintainer, reviewed and merged 51 patches from other contributors
  • Maxime Ripard as the Allwinner platform co-maintainer, reviewed and merged 38 patches from other contributors
  • Alexandre Belloni as the RTC maintainer and Microchip platform co-maintainer, reviewed and merged 36 patches from other contributors
  • Grégory Clement as the Marvell EBU platform co-maintainer, reviewed and merged 9 patches from other contributors

Here is the details of all our contributions, patch by patch: