Thomas Petazzoni – Page 30

Bootlin welcomes Boris Brezillon and Antoine Ténart

We are happy to announce that our engineering team has recently welcomed two new embedded Linux engineers: Boris Brezillon and Antoine Ténart. Boris and Antoine will both be working from the Toulouse office of the company, together with Maxime Ripard and Thomas Petazzoni. They will be helping Bootlin to address the increasing demand for its development and training services.

Antoine started his professional experience with Embedded Linux and Android in 2011. Before joining Bootlin in 2014, he started with low level Android system development at Archos (France), and worked on Embedded Linux and Android projects at Adeneo Embedded (France). He joined Bootlin early March, and has already been involved in kernel contributions on the Marvell Berlin processors and the Atmel AT91 processors, and is also working on our upcoming Yocto training course.

Boris joined Bootlin on April, 1st, and brings a significant embedded Linux experience that he gained while working on home automation devices at Overkiz (France). He was maintaining a custom distribution built with the Yocto. Boris also has already contributed many patches to the mainline Linux kernel sources, in particular for the Atmel AT91 ARM SoCs. Boris is also developing the NAND controller driver for the Allwinner ARM processors and has proposed improvements to the core Linux MTD subsystem (see this thread and this other thread).

Embedded Linux Conference 2014, Bootlin participation

One of the most important conference of the Embedded Linux community will take place at the end of this month in California: the Embedded Linux Conference will be held in San Jose from April, 29th to May, 1st, co-located with the Android Builders Summit. The schedule for both of these events has been published, and it is full of interesting talks on a wide range of embedded topics.

As usual, Bootlin will participate to this conference, but this participation will be the most important ever:

No less than seven engineers from Bootlin will participate to the event, which is almost our entire engineering team: Alexandre Belloni, Maxime Ripard, Boris Brezillon, Antoine Ténart, Grégory Clement, Michael Opdenacker and Thomas Petazzoni. Only Ezequiel Garcia will be missing.
Seven talks or BOFs from Bootlin engineers are part of the conference schedule:
- Update on Boot Time Reduction Techniques, with Figures – Michael Opdenacker
- Device Tree for Dummies – Thomas Petazzoni
- Two Years of ARM SoC Support mainlining: Lessons Learned – Thomas Petazzoni
- SMP Bring Up On ARM SOCs – Gregory Clement
- Buildroot: What’s New? (BoF) – Thomas Petazzoni
- Using Yocto For Modules Manufacturers – Alexandre Belloni
- Supporting A New ARM platform: The Allwinner SoCs Example – Maxime Ripard

If you are interested in embedded Linux, we highly advise you to attend this conference. And if you are interested in business or recruiting opportunities with Bootlin, it will also be the perfect time to meet us!

Linux 3.14 released, Bootlin contributions inside!

Linus Torvalds has just released the 3.14 version of the Linux kernel. As usual, it incorporates a large number of changes, for which a good summary is available on the KernelNewbies site.

This time around, Bootlin is the 19th company contributing to this kernel release, by number of patches, right between Cisco and Renesas. Six of our engineers have contributed to this release: Maxime Ripard, Alexandre Belloni, Ezequiel Garcia, Grégory Clement, Michael Opdenacker and Thomas Petazzoni. In total, they have contributed 121 patches to this kernel release.

By far, the largest number of patches are related to the addition of NAND support for the Armada 370 and Armada XP processors. This required a significant effort, done by Ezequiel Garcia, to re-use the existing pxa3xx_nand driver and extend it to cover the specificities of the Armada 370/XP NAND controller. And these specificities were quite complicated, involving a large number of changes to the driver, which all had to also be validated on existing PXA3xx hardware to not introduce any regression.
Support for high speed timers on various Allwinner SOCs has been added by Maxime Ripard.
Support for the Allwinner reset controller has been implemented by Maxime Ripard.
SMP support for the Allwinner A31 SOC was added by Maxime Ripard.
A number of small fixes and improvements were made to the AT91 pinctrl driver and the pinctrl subsystem by Alexandre Belloni.
Michael Opdenacker continued his quest to finally get rid of the IRQF_DISABLED flag.
A number of fixes and improvements were made by Grégory Clement and Thomas Petazzoni on various Armada 370/XP drivers: fix for the I2C controller on certain early Armada XP revisions, fixes to make the Armada 370/XP network driver usable as a module, etc.

In detail, our contributions were:

Buildroot meeting and FOSDEM report, Google Summer of Code topics

As we discussed in a recent blog post, two of our engineers participated to the FOSDEM conference early February in Brussels, Belgium. For those interested, many videos are available, such as several videos from the Lameere room, where the embedded related talks were given.

Thomas Petazzoni also participated to the two days Buildroot Developers Meeting after the FOSDEM conference. This meeting gathered 10 contributors to the Buildroot project physically present and two additional remote participants. The event was sponsored by Google and Mind, thanks a lot to them! During those two days, the participants were able to discuss a very large number of topics that are often difficult to discuss over mailing lists or IRC, and a significant work to clean up the oldest pending patches was done. In addition to this, these meetings are also very important to allow the contributors to know each other, as it makes future online discussions and collaborations much easier and fruitful. For more details, see the complete report of the event.

Buildroot Developers Meeting in Brussels

Also, if you’re interested in Buildroot, the project has applied to participate to the next edition of the Google Summer of Code. Two project ideas are already listed on the project wiki, feel free to contact Thomas Petazzoni if you are a student interested in these topics, or if you have other proposals to make for Buildroot.

Bootlin contributions to Linux 3.13

Version 3.13 of the Linux kernel was released by Linus Torvalds on January, 19th 2014. The kernelnewbies.org site has an excellent page that covers the most important improvements and feature additions that this new kernel release brings.

As usual Bootlin contributed to this kernel: with 121 patches merged in 3.13 on a total of 12127 patches contributed, Bootlin is ranked 17th in the list of companies contributing to the Linux kernel. We also appeared on Jonathan Corbet kernel contribution statistics at LWN.net, as a company having contributed 1% of the kernel changes, right between Renesas Electronics and Huawei Technologies.

Amongst the contributions we made for 3.13:

Standby support added to the Marvell Kirkwood processors, done by Ezequiel Garcia.
Various fixes and improvements to the PXA3xx NAND driver, as well as to the Marvell Armada 370/XP clocks, in preparation to the introduction of NAND support for Armada 370/XP, which will arrive in 3.14. Work done by Ezequiel Garcia.
Added support for the Performance Monitoring Unit in the AM33xx Device Tree files, which allows to use perf and oprofile on platforms such as the BeagleBone. Work done by Alexandre Belloni.
Support added for the I2C controllers on certain Allwinner SOCs, as well as several other cleanups and minor improvements for these SoCs. Work done by Maxime Ripard.
Continued the work to get rid of IRQF_DISABLED, as well as other janitorial tasks such as removing unused Kconfig symbols. Work done by Michael Opdenacker.
Added support for MSI (Message Signaled Interrupts) for the Armada 370 and XP SoCs. Work done by Thomas Petazzoni.
Added support for the Marvell Matrix board (an Armada XP based platform) and the OpenBlocks A7 (a Kirkwood based platform manufactured by PlatHome). Work done by Thomas Petazzoni.

In detail, the patches contributed by Bootlin are:

Bootlin at FOSDEM and at the Buildroot Developers Meeting

This week-end is the first week-end of February, which on the schedule of all open-source developers is always booked for a major event of our community: the FOSDEM conference in Brussels. With several hundreds of talks over two days, this completely free event is one of the biggest event, if not the biggest of the open-source world.

For embedded Linux developers, FOSDEM has quite a few interesting tracks and talks this year: an embedded track, a graphics track (with many embedded related talks, such as talks on Video4Linux, the status of open-source drivers for 2D and 3D graphics on ARM platforms, etc.), and several talks in other tracks relevant to embedded developers. For example, there is one talk about the Allwinner SoCs and the community behind it in one of the main track. Our engineer Maxime Ripard is the Linux kernel maintainer for this family of SoC.

Two Bootlin engineers will attend FOSDEM: Maxime Ripard and Thomas Petazzoni. Do not hesitate to get in touch with them if you want to discuss embedded Linux or kernel topics!

Also, right after FOSDEM, the Buildroot community is organizing its Developers Meeting, on Monday, 3rd and Tuesday 4th February. This event is sponsored by Google (providing the meeting location) and Mind (providing the dinner), and will take place in the offices of Google in Brussels. Ten Buildroot developers will participate to the meeting in Brussels, as well as a number of others remotely. On Bootlin side, Thomas Petazzoni will be participating to the meeting. If you are interested in participating, either physically or remotely, do not hesitate to contact Thomas to register. For more details, see the wiki page of the event.

Bootlin at Linux Conf Australia, January 2014

Linux Conf Australia is by far the most well-known Linux related conference of the southern hemisphere, with a good number of Linux kernel related talks and discussions, as well as many other topics around the Linux ecosystem. The 2014 edition of the event will take place in Perth, Australia, and the schedule of talks and mini-confs looks very promising!

For the first time, Bootlin will be participating to this conference: our CTO and embedded Linux engineer Thomas Petazzoni will be giving a talk titled Buildroot: building embedded Linux systems made easy!, during which he will be presenting what Buildroot is, what it is useful for, and how it works.

Beyond this talk, Thomas will be attending the full week of conferences, so do not hesitate to get in touch with him, especially if you’re interested in embedded Linux topics, Buildroot, ARM kernel development, and in Bootlin!

Updated version of our kernel driver development course: Device Tree, BeagleBone Black, Wii Nunchuk, and more!

BeagleBone Black connected to the Wii Nunchuk over I2C

In the last few years, the practical labs of our Embedded Linux kernel and driver development training were based on the ARMv5 Calao USB-A9263 platform, and covering the ARM kernel support as it was a few years ago. While we do regularly update our training session materials, with all the changes that occurred in the ARM kernel world over the last two years, it was time to make more radical changes to this training course. This update is now available since last month, and we’ve already successfully given several sessions of this updated course.

The major improvements and updates are:

All the practical labs are now done on the highly popular ARMv7 based BeagleBone Black, which offers much more expansion capabilities than the Calao USB-A9263 platform we were using. This also means that participants to our public training sessions keep the BeagleBone Black with them after the session!
All the course materials and practical labs were updated to cover and use the Device Tree mechanism. We also for example cover how to configure pin muxing on the BeagleBone Black through the Device Tree.
The training course is now centered around the development of two device drivers:
1. A driver for the Wii Nunchuk. This device is connected over I2C to the BeagleBone Black, and we detail, step by step, how to write a driver that communicates over I2C with the device and then exposes the device functionalities to userspace through the input kernel subsystem.
2. A minimal driver for the OMAP UART, which we use to illustrate how to interface with memory-mapped devices: mapping I/O registers, accessing them, handling interrupts, putting processes to sleep and waking them up, etc. We expose some minimal functionality of the device to userspace through the misc kernel subsystem. This subsystem is useful to expose the functionalities of non-standard types of devices, such as custom devices implemented inside FPGAs.

And as usual, all the training materials are freely available, under a Creative Commons license, so you can study in detail the contents of the training session. It is also worth mentioning that this training session is taught by Bootlin engineers having practical and visible experience in kernel development, as can be seen in the contributions we made in the latest kernel releases: 3.9, 3.10, 3.11 and 3.12.

For details about cost and registration, see our Training cost and registration page.

Videos and slides of the Kernel Recipes 2013 conference

As we mentionned earlier on this blog, Bootlin participated to the second edition of the Kernel Recipes conference in Paris, a two-days conference dedicated to kernel topics.

The videos and slides of the talks in this conference have now been published, see https://kernel-recipes.org/en/2013/conferences/ for the complete list. There is a good number of interesting topics: discussion about kernel development environment by Willy Tarreau, status of Nftables and Netfilter in general by Eric Leblond, a talk explaning how to decipher kernel oopses, a talk about Crosstool-NG from Yann E. Morin, a discussion about Linux Security Modules, a talk about the status of Display support in the kernel by Laurent Pinchart, and several lightning talks.

The talks from Bootlin were:

Bootlin really enjoyed this conference, and is looking forward to participating again next year. Thanks a lot to the organizers!

Linux 3.12 released, Bootlin 14th contributor by number of commits

The 3.12 kernel has just been released by Linus Torvalds, who summarized what he considers to be the major improvements offered by this release: improvements to the dynamic tick code, support infrastructure for DRM render nodes, TSO sizing and the FQ scheduler in the network layer, support for user namespaces in the XFS filesystem, multithreaded RAID5 in the MD subsystem, offline data deduplication in the Btrfs filesystem.

As usual, Bootlin contributed to the Linux kernel during this cycle, and according to the statistics at KPS, Bootlin is the 14th contributor in terms of number of commits, as a company. Bootlin contributed 185 patches to this kernel release, on a total of 10920 patches. Note that this classification includes the “Unknown” company which ranks first, gathering the contributions from all the contributors that are not known to be affiliated to any company.

The highlights of our contributions are:

Addition of support for the HX8369 LCD controller to the driver we had contributed earlier for the HX8357 LCD controller, in drivers/video/backlight/hx8357.c. These LCD controllers are used by the Crystalfontz i.MX28 boards, and this new development was done primarily by Alexandre Belloni.
Addition of a driver for the Nuvoton NAU7802 ADC chip on I2C, in drivers/iio/adc/nau7802.c. Some initial work was done by Maxime Ripard, but lots of debugging and additional work was done by Alexandre Belloni, who also pushed the driver to the mainline.
Added Device Tree information for the PMU unit on Atmel SAMA5D3 platforms, which allows to use perf on these platforms. Done by Alexandre Belloni.
Addition of a Device Tree binding to the mvebu-mbus driver, which controls the configuration of the MBus on Marvell EBU platforms (Armada 370/XP, Kirkwood, Dove, etc.). This binding took a lot of discussion time, and many iterations before reaching a state that was considered acceptable for mainline, but it has finally been merged in 3.12. The core of this work was done by Ezequiel Garcia, with several contributions from Thomas Petazzoni to convert existing platforms to the new APIs.
Many cleanups and improvements to the nand_pxa3xx driver, which for the moment is used for the NAND controller on PXA3xx, but that we are currently extending to also cover the NAND controller of Armada 370/XP platforms. In 3.12, only some cleanups have been integrated, and we are currently submitting the more important patches for mainline integration. This work was done by Ezequiel Garcia.
Cleanups, and conversion to CLOCKSOURCE_OF_DECLARE of the Armada 370/XP clocksource driver. Done by Ezequiel Garcia.
Extension of the Marvell I2C driver to use a new feature of the I2C controller found on Armada 370/XP, which allows to program an entire transaction at once, instead of having interrupts at each step of the transaction. This work was done by Gregory Clement.
The quest of removing unneeded ->init_irq() callbacks in machine descriptors continued, with Maxime Ripard removing 4 additional occurrences of this in mach-shmobile.
Cleanups and improvements to the sun4i clocksource driver, used on Allwinner SOCs. Done by Maxime Ripard.
Introduction of the initial support for the Allwinner A31 SOC and its WITS Columbus evaluation kit, as well as initial support for the Allwinner A20 SOC and the Olimex A20-Olinuxino-Micro and Cubieboard2 board, both based on the Allwinner A20 SOC. This includes clock support, pinctrl support, Ethernet support where applicable, and more. Work done by Maxime Ripard.
Michael Opdenacker continued his fight against IRQF_DISABLED and removed more occurrences of them. Michael also fixed a few issues in some Kconfig files.
Fixed big-endian issues in the Marvell mvneta Ethernet driver and the Marvell XOR driver, in preparation for the addition of big-endian support to the mach-mvebu platform. Done by Thomas Petazzoni.
Conversion of a few more Kirkwood platforms to the Device Tree, and removal of legacy support for other Kirkwood platforms that were already converted to the Device Tree. Done by Thomas Petazzoni.
Addition of the support for the Armada XP based AXP-WiFi AP board, from Marvell. Done by Thomas Petazzoni.
Improvements of the MSI infrastructure in the kernel: consolidation of code between architectures, addition of a registry of msi_chip. This preparatory work was needed to introduce MSI support for Armada 370/XP, which should hopefully make its way into 3.13. Work done by Thomas Petazzoni.

In details, our contributions were: