kernel – Page 4

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 couch Like 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. For our embedded Linux and Yocto Project courses, we propose an additional date in case some extra time is needed to complete the agenda.

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)	Sep. 28, 29, 30, Oct. 1, 2, 5, 6 2020.	17:00 – 21:00 (Paris), 8:00 – 12:00 (San Francisco)	28 h	Michael Opdenacker	829 EUR + VAT^* (register)
Embedded Linux (agenda)	Nov. 2, 3, 4, 5, 6, 9, 10, 12, 2020.	14:00 – 18:00 (Paris), 8:00 – 12:00 (New York)	28 h	Michael Opdenacker	829 EUR + VAT^* (register)
Linux kernel (agenda)	Nov. 16, 17, 18, 19, 23, 24, 25, 26	14:00 – 18:00 (Paris time)	28 h	Alexandre Belloni	829 EUR + VAT^* (register)
Yocto Project (agenda)	Nov. 30, Dec. 1, 2, 3, 4, 2020	14:00 – 18:00 (Paris time)	16 h	Maxime Chevallier	519 EUR + VAT^* (register)
Buildroot (agenda)	Dec. 7, 8, 9, 10, and 11, 2020	14:00 – 18:00 (Paris time)	16 h	Thomas Petazzoni	519 EUR + VAT^* (register)
Linux Graphics (agenda)	Dec. 1, 2, 3, 4, 2020	14:00 – 18:00 (Paris time)	16 h	Paul Kocialkowski	519 EUR + VAT^* (register

^* VAT: applies to businesses in France and to individuals from all countries. Businesses in the European Union won’t be charged VAT only if they provide valid company information and VAT number to Evenbrite at registration time. For businesses in other countries, we should be able to grant them a VAT refund, provided they send us a proof of company incorporation before the end of the session.

Each public session will be confirmed once there are at least 6 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 Jitsi Meet, a Free Software solution that we are trying to promote. As a backup solution, we will also be able to Google Hangouts Meet. 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.

Each participant is asked to connect 15 minutes before the session starts, to make sure her or his setup works (instructions will be sent before the event).

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 training@bootlin.com 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 : Should I order hardware in advance, our hardware included in the training cost?
R : No, practical labs are replaced by technical demonstrations, so you will be able to follow the course without any hardware. However, you can still order the hardware by checking the “Shopping list” pages of presentation materials for each session. This way, between each session, you will be able to replay by yourself the labs demonstrated by your trainer, ask all your questions, and get help between sessions through our dedicated Matrix channel to reach your goals.

Q: Why just demos instead of practicing with real hardware?
A: We are not ready to support a sufficient number of participants doing practical labs remotely with real hardware. This is more complicated and time consuming than in real life. 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: Would it be possible to run practical labs on the QEMU emulator?
R: Yes, it’s coming. In the embedded Linux course, we are already offering instructions to run most practical labs on QEMU between the sessions, before the practical demos performed by the trainer. We should also be able to propose such instructions for our Yocto Project and Buildroot training courses in the next months. Such work is likely to take more time for our Linux kernel course, practical labs being closer to the hardware that we use.

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 a small break in the middle) is a good solution, also leaving extra time for following up your normal work.

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

Linux This 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

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:

Linux 5.0 released, Bootlin contributions

Linux 5.0 was released two weeks ago by Linus Torvalds, and as it is now always the case, Bootlin has contributed a number of patches to this release. For an overview of the new features and improvements brought by Linux 5.0, we as usual recommend to read the LWN articles: merge window summary part 1, merge window summary part 2. The KernelNewbies.org page about this kernel release is also nicely documented.

In terms of contribution to Linux 5.0, according to the LWN statistics, Bootlin is the 12th contributing company by number of commits (261 commits), and 8th contributing company by number of changed lines. Bootlin engineer Maxime Ripard is 11th contributing developer by number of commits, and former Bootlin engineer Boris Brezillon is 12th contributing developer by number of commits, and 8th by number of changed lines. In this release, we are also happy to see numerous contributions from Paul Kocialkoswki who joined Bootlin in November 2018 after his internship working on the Linux kernel support for the Allwinner VPU.

Here are the main highlights of our contributions to Linux 5.0:

After 1.5 years of work, the I3C subsystem was finally merged and visible in drivers/i3c in your favorite kernel tree! We are proud to have pioneered the Linux kernel support for this new MIPI standard, which aims at providing an alternate solution to I2C and SPI, with interesting new features (higher speed, device discovery and enumeration, in-band interrupts, and more). See also our initial blog post about I3C, and our blog post about I3C being upstream.
In the RTC subsystem, Bootlin engineer and RTC kernel maintainer Alexandre Belloni reworked the way nvmem devices are handled, allowing for multiple nvmem devices to be registered for a single RTC as some have both battery-backed RAM and an on-chip EEPROM. devm_rtc_device_register() has been reimplemented to use the new registration path and is now deprecated. Its counterpart, devm_rtc_device_unregister() has been removed.
In the MTD subsystem
- Boris Brezillon contributed a number of patches to the support for raw NAND mainly related to refactoring the subsystem. For example, some of the patches make the ->select_chip() of nand_chip a legacy hook, and removes its implementation from a number of drivers. All those patches do not bring any new feature per-se, but are part of a larger effort to clean up and modernize the MTD subsystem.
- Boris Brezillon also contributed to the SPI NOR support a mechanism to fixup the information provided in the BFPT table of SPI NOR flashes. This is used to ensure that some Macronix SPI NOR flashes are properly recognized as supporting 4-byte opcodes.
Maxime Ripard contributed a number of improvements to the OV5640 camera sensor driver, especially to remove the hardcoded initialization sequence by a much more flexible initialization code, which allowed to support 60fps and more resolutions.
Maxime Ripard extended the PHY subsystem with two new functions, phy_configure() and phy_validate(), which allow to pass configuration details to PHY drivers. This was then used by Maxime to implement MIPI D-PHY drivers, which need a significant number of configuration parameters. See this commit and this commit for details. MIPI D-PHY are typically used in video display or capture HW pipelines.
As part of our work on RaspberryPi display support, Boris Brezillon contributed a number of fixs to the VC4 display controller driver.
For the support of Microchip MPU (Atmel) platforms, Alexandre Belloni migrated the AT91SAM9260, AT91SAM9261, AT91SAM9263, AT91SAM9RL, AT91SAM9x5, SAMA5D2 and SAMA5D4 platforms to the new clock Device Tree binding that he introduced in Linux 4.20.
For the support of Microchip UNG (formerly Microsemi) platforms, Alexandre Belloni added support for the Jaguar2 platform to the pinctrl driver already used for the Ocelot platform.
For the support of Allwinnner platforms:
- Maxime Ripard did a huge amount of Device Tree cleanups and improvements, fixing DTC warnings, but generally making sure those Device Tree files are consistent.
- Paul Kocialkowski implemented support for YUV planes in the Allwinner display controller driver. This allows to display a video decoded by the VPU directly into a display controller plane, and let the hardware compose it with other display planes, without CPU intervention.
- Paul Kocialkowski enabled the VPU (for hardware-accelerated video decoding) on the Allwinner H5 and A64. This work was part of our crowdfunding campaign around the Allwinner VPU support.
For the support of Marvell platforms
- Miquèl Raynal added support for suspend/resume to the SATA support on Armada 3720 (the SoC used for the popular EspressoBin platform), as part of a larger effort of bringing full suspend/resume support on Armada 3720
- Miquèl Raynal implemented support for the thermal overheat interrupt on Armada 7K/8K.

Here is the detailed list of commits we contributed to Linux 5.0:

Free seats in embedded Linux and kernel training sessions (Mar 2019)

Student penguins At Bootlin, we owe a lot to the Free Software community, and we’re doing our best to give back as much as we can.

One way of doing that is welcoming community contributors in our public training sessions organized in France. We’ve done that multiple times several years back, and this allowed us to meet very interesting people (who even had very valuable experience and points of view to share with the other course participants), while of course giving them extra knowledge that they can use for further contributions.

Here are the next sessions in which we can offer a free seat:

Embedded Linux system development course, Mar. 4-8, 2019 in Avignon, France. Apply by Feb. 17. The winner will be selected and notified by Feb. 19.
Linux kernel and driver development course, Mar 25-29, 2019 in Avignon, France. Apply by Mar. 10. The winner will be selected and notified by Mar. 12.

See our Free training seats page for practical details about how to apply.

Don’t hesitate to apply to this free seat. In past editions, we didn’t have so many people applying, and therefore you have a real chance to get selected!

MIPI I3C support is now in upstream Linux

MIPI I3C specification published Back in August 2017, we wrote in a blog post about the first iteration of the Linux kernel subsystem we proposed to support the brand new MIPI I3C bus. Almost a year and half later, there are some really good news:

The Linux I3C support now has its own Git repository on kernel.org
The Linux I3C community has its mailing list.
Besides the first I3C controller driver we wrote for the Cadence I3C Master, Synopsys has contributed a second driver for their I3C master IP: i3c: master: Add driver for Synopsys DesignWare IP. This definitely helped show that there is interest in I3C beyond our contributions, and also helped validate that the subsystem was working fine for a different I3C controller.
The Linux I3C tree has been part of linux-next since November 6, 2018: linux-next: Tree for Nov 6.
The Linux I3C subsystem has received a Reviewed-by: Arnd Bergmann and later on a Acked-by: Greg Kroah-Hartman, which were two key approvals to move forward with the merging of I3C support.
I3C subsystem maintainer Boris Brezillon has therefore sent a pull request to get this subsystem merged in the upcoming 4.21 (or 5.0 ?) Linux kernel: [GIT PULL] i3c: Initial pull request, and this pull request has been merged by Linus Torvalds, so the I3C subsystem is now visible in Linus Git tree: drivers/i3c. The merge commit has been done on December 25, so it arrived as a very nice Christmas present!

It has been a long process, but we are proud and happy to have pioneered the support for I3C in the Linux kernel, from the design of the subsystem based on the I3C specifications all the way to its merging in the upstream Linux kernel and the creation of a small (but hopefully growing) community of developers around it.

Linux 4.19 released, Bootlin contributions

With the 4.19 released last week by Greg Kroah-Hartman (and not Linus), it’s time to have a look at our contributions for this release.

As always, LWN.net did an interesting coverage of this release cycle merge window, highlighting the most important changes: the first half of the 4.19 merge window and the rest of the 4.19 merge window. For 4.19 only, Bootlin contributed a total of 295 patches, which puts us at the 10th place in the ranking of most contributing companies according to KPS.

Also according to LWN statistics, Bootlin’s engineer Boris Brezillon is the 16th most active developer in terms of commits for this release with a total of 85.

The main highlights of our contributions are:

For Marvell platforms:
- Antoine Ténart made a few fixes and improvements to the inside-secure cryptographic engine driver and contributed support for SHA512, SHA384 and eip197d. This crypto engine is used on Marvell Armada 3700 and 7K/8K,
- Maxime Chevallier added support for Receive Side Scaling (RSS), in the PPv2 Ethernet controller driver found on Marvell 7K and 8K platforms,
- Gregory Clement added support for Adaptative Voltage Scaling (AVS) used by DVFS and more specifically by CPUfreq on Armada 37xx platforms,
- Miquèl Raynal added support for suspend/resume in the pinctrl driver for Marvell Armada 37xx family,
- Miquèl Raynal added support for multi-channel sensor in the thermal driver for Marvell SoCs,
- Thomas Petazzoni fixed a few bugs found in the PCI mvebu controller driver,
In the MTD subsystem:
- Boris Brezillon contributed the support for the MX35LF1GE4AB SPI NAND chip,
- Miquèl Raynal added the support for the MX35LF2GE4AB SPI NAND chip,
- Miquèl Raynal converted NAND drivers to the added nand_scan() hook,
- Miquèl Raynal and Boris Brezillon continued their cleanup of the NAND subsystem,
For Microsemi Ocelot platforms:
- Alexandre Belloni added link aggregation hardware offload support to the Ethernet switch driver that was contributed in Linux 4.18,
- Antoine Ténart contributed VLAN support also in the Ethernet switch driver that was contributed in Linux 4.18,
- Alexandre Belloni added support for the SPI controllers,
- Quentin Schulz added support for the interrupt controller on GPIO pins,
For Allwinner platforms:
- Boris Brezillon fixed an overflow in the dotclock driver of the Allwinner DRM driver,
- Paul Kocialkowski fixed an issue in the DRM driver on sun8i SoC family where planes untouched by an atomic commit are not displayed,
- Maxime Ripard added support for the C1 SRAM region on sun5i, sun7i and sun8i SoC families, which was needed to support the VPU (coming in future Linux kernel versions)
Maxime Chevallier improved PIO transfers on the SPI imx driver to support non-multiple of 8 bits_per_word and dynamic_burst transfers,

Bootlin engineers are not only contributors, but also maintainers of various subsystems in the Linux kernel, which means they are involved in the process of reviewing, discussing and merging patches contributed to those subsystems:

Maxime Ripard, as the Allwinner platform co-maintainer, merged 93 patches from other contributors
Boris Brezillon, as the MTD/NAND maintainer, merged 38 patches from other contributors
Miquèl Raynal, as the NAND co-maintainer, merged 110 patches from other contributors
Alexandre Belloni, as the RTC and Microsemi maintainer and Atmel platform co-maintainer, merged 38 patches from other contributors
Grégory Clement, as the Marvell EBU co-maintainer, merged 16 patches from other contributors

Here is the commit by commit detail of our contributions to 4.19:

Linux 4.15 released, Bootlin contributions

After a month of February busier than usual, with the renaming of our company from Free Electrons to Bootlin, our participation to FOSDEM and the welcoming of Maxime Chevallier, the latest addition to our engineering team, our article on the latest release of the Linux kernel arrives a bit late, more than a month after Linux 4.15 has been released by Linus Torvalds.

As usual, LWN.net did an interesting coverage of this release cycle merge window, highlighting the most important changes: The first half of the 4.15 merge window and The rest of the 4.15 merge window. Due to the now well-known Spectre and Meltdown vulnerabilities and the resulting effort to try to mitigate them, 4.15 required a -rc9, which happened the last time back in 2011 with the 3.1, Torvalds said.

According to Linux Kernel Patch statistics, Bootlin (now Bootlin) contributed 150 patches to this release, making it the 16th contributing company by number of commits.

The main highlights of our contributions are:

In the RTC subsystem, Alexandre Belloni made a number of improvements to various drivers, mainly making them use the nvmem subsystem where appropriate, and use the recently introduced rtc_register_device() API.
In the MTD subsystem, both Boris Brezillon and Miquèl Raynal made a number of contributions, mainly fixes.
For Marvell platforms
- Antoine Ténart contributed a few fixes to the inside-secure crypto accelerator driver, used on Marvell Armada 3700 and Armada 7K/8K
- Antoine Ténart also contributed fixes and improvements to the mvpp2 network driver, used for the Ethernet controller on the Marvell Armada 7K/8K. His improvements include preparation work to support Receive Side Scaling (RSS).
- Antoine Ténart enabled more networking ports and features in some Armada 7K/8K boards, especially SFP ports on Armada 7040 DB and Armada 7040 DB.
- Boris Brezillon contributed a few fixes to the Marvell CESA crypto accelerator driver, used on the older Orion, Kirkwood, Armada 370/XP/38x processors. He migrated the driver to use the skcipher interface of the Linux kernel crypto framework.
- Grégory Clement enabled NAND support on Armada 7K, and contributed a number of fixes around MMC support for some Marvell boards.
- Thomas Petazzoni contributed a few minor Device Tree enhancements for Marvell platforms: fixing MPP muxing on an older Kirkwood platform, enabling more PCIe ports on Armada 8040 DB, etc.
- Miquèl Raynal contributed support for more advanced statistics in the mvpp2 network driver.
- Miquèl Raynal added support for the extended UART for the Marvell Armada 3720 processor, both in the UART driver and in the Device Tree.
For the RaspberryPi platform, Boris Brezillon contributed a few fixes to the vc4 display driver, and added support for the new DRM_IOCTL_VC4_GEM_MADVISE ioctl, which can be used to ask the userspace applications to purge inactive buffers when allocations start to fail in the kernel.
For Allwinner platforms
- Mylène Josserand contributed a fix for the Allwinner A83 clock driver, fixing I2C bus clocks.
- Quentin Schulz contributed a few fixes to the sun4i-gpadc-iio.c driver, which is used for the ADCs on several Allwinner processors.
- Maxime Ripard made a number of fixes to the sun8i-codec driver, fixing clock issues, left/right channels inversion, etc.
- Maxime Ripard made a number of improvements to the sun4i DRM display driver.
- Maxime Ripard improved the support for the A83 processor (described the UART1 controller, the MMC1 controller, added support for display clocks) and added the Device Tree for a new A83 device.
- Maxime Ripard also did a number of cleanups and misc improvements in a significant number of Device Tree files for Allwinner platforms.
Thomas Petazzoni made a few fixes to the sh_eth network driver, used on several Renesas SuperH platform, as part of a recent project Bootlin did on SuperH 4.

Maxime Ripard, as the Allwinner platform co-maintainer, merged 108 patches from other contributors
Boris Brezillon, as the MTD/NAND maintainer, merged 34 patches from other contributors
Alexandre Belloni, as the RTC maintainer and Atmel platform co-maintainer, merged 50 patches from other contributors
Grégory Clement, as the Marvell EBU co-maintainer, merged 24 patches from other contributors

Here is the commit by commit detail of our contributons to 4.15: