Linux 3.15 released, an overview of Free Electrons contributions

The 3.15 of the Linux kernel was released just a few days ago by Linus Torvalds. As explained by LWN.net, the headline features in 3.15 include some significant memory management improvements, the renameat2() system call, file-private POSIX locks, a new device mapper target called dm-era, faster resume from suspend, and more. One can also read the coverage by LWN.net of the first part and the second part of the merge window to get more details about the major new features in this release.

As usual, Free Electrons contributed to the Linux kernel during this 3.15 cycle, and with a total of 218 patches contributed, it’s a new record for Free Electrons. According to the KPS statistics, Free Electrons ranked #12 in the list of companies contributing to the Linux kernel for the 3.15 kernel (if you exclude the “Unknown” and “Hobbyists” categories, which aren’t really companies).

The main features contributed by Free Electrons again centered around the support for ARM processors:

  • By far, the largest contribution this cycle was the initial support for the new Armada 375 and Armada 38x processors from Marvell. Gregory Clement, Ezequiel Garcia and Thomas Petazzoni have been working on the code to support these processors since a few months ago, and started pushing the patches to the public in February this year. For the Marvell Armada 38x processor, it means that the code was pushed in mainline even before the processor was announced publicly! The features supported in 3.15 for these processors are: interrupts, GPIO, clocks, pin-muxing, serial, I2C, SPI, timer, L2 cache, SDIO (only for 375), SATA (only 375), XOR, PCIe, MBus, networking (only for 38x), NOR and NAND support. Many other features such as SMP, I/O coherency and various other peripherals will be supported in 3.16.
  • Convert support for the Atmel AT91SAM9RL processor to the Device Tree, done by Alexandre Belloni.
  • Addition of iio-hwmon to the Freescale i.MX23 and i.MX28 processors, which allows to use the internal temperature sensor of the processor. Done by Alexandre Belloni.
  • Multiple fixes and improvements to the AT91 ADC support. Done by Alexandre Belloni.
  • Support for the watchdog in Armada 370 and Armada XP was added, done by Ezequiel Garcia.
  • A driver for the SPI controller found in Allwinner A31 SoC was added, as well as all the Device Tree information to describe this controller and related clocks. Done by Maxime Ripard.
  • Support for the I2C controller found in the Allwinner A31 SoC was added into the existing mv64xxx-i2c driver, as well as the necessary Device Tree information to use I2C on this SoC. Done by Maxime Ripard.
  • Audio support was enabled on the Armada 370 SoC, re-using existing code for Kirkwood, and therefore making audio work on the Armada 370 DB platform. Done by Thomas Petazzoni.
  • A number of issues in the PCIe support for Marvell processors have been fixed, thanks to the reports from a number of users. Done by Thomas Petazzoni, with help from these users.

We also contributed other things than just support for ARM processors:

  • The main contribution in this area is the addition of UBI block, a driver that allows to use read-only block filesystems such as squashfs on top of a UBI volume. The code was originally written by David Wagner who was an intern at Free Electrons, and later taken by Ezequiel Garcia who did a lot of additional cleanup work and community discussion to get the driver merged. Some details about this feature can be found in the Linux-MTD documentation.
  • A generic Device Tree binding to express NAND ECC related information in the Device Tree was contributed by Ezequiel Garcia.
  • The quest to remove IRQF_DISABLED continued, by Michael Opdenacker.

In details, all our contributions are:

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Marvell publishes the datasheet of the Armada 370 processor

thumb-armada-xpOver the last two years, Free Electrons has contributed support for the Marvell Armada 370 and Marvell Armada XP processors to the mainline Linux kernel. These ARM processors are used mainly in Network Attached Storage devices but also in other devices such as printers. Until now the datasheet for these processors was only available for Marvell customers and partners under NDA, but last week, Marvell finally released the datasheet of the Armada 370 publicly, with no restriction, no registration, no NDA. The Armada 370 processor can already be found in several consumer grade products:

From now on, on the Marvell page related to the Armada 3xx family, the Armada 370 Functional Specification as well as the Armada 370 Hardware Specifications can be found. While the Armada XP datasheet is not available at this time, it is worth mentioning that the vast majority of the peripherals are exactly the same between Armada 370 and Armada XP, so even Armada XP users will find useful information in this datasheet.

Free Electrons is happy to see that Marvell is making more and more progress towards mainlining their kernel support and opening their datasheets publicly. We strongly believe that the openness of these datasheets will allow hobbyists and developers to improve the support for Armada 370 in the open-source ecosystem, be it in the Linux kernel, in bootloaders like U-Boot or Barebox or even in other projects.

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Embedded Linux course in Madrid – July 7-11

We are happy to announce a new Embedded Linux training course on July 7-11, in Madrid, Spain.

It is organized by our partners ISEE (the makers of the IGEPv2 board that we are using in this course), and Silica, a well known component is distributor who is welcoming the session in its offices in Madrid.

The course will be instructed in English by our trainer Marcin Bis. Marcin Bis

The registrations are directly handled by ISEE. See the flyer (document in Spanish) for this session for all practical details and for registration details.

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2014 Q2 newsletter

This article was published on our quarterly newsletter.

Free Electrons is happy to share some news about the latest training and contribution activities of the company.

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Free Electrons welcomes Boris Brezillon and Antoine Ténart

Boris Brezillon
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 Free Electrons 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 Free Electrons 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 Free Electrons 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 Free Electrons 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).

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Embedded Linux Conference 2014, Free Electrons participation

San JoséOne 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, Free Electrons will participate to this conference, but this participation will be the most important ever:

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 Free Electrons, it will also be the perfect time to meet us!

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Linux 3.14 released, Free Electrons 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, Free Electrons is the 21st 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:

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Free Electrons at Embedded World 2014, Nuremberg, Germany

Embedded World 2014, Germany

Embedded World is the world’s largest trade show about embedded systems. In 2013, it attracted around 900 exhibitors, over 22,000 visitors and almost 1,500 congress participants.

This year, Free Electrons will be represented by our CEO Michael Opdenacker. This should be a great opportunity for us to understand our customers better, by meeting embedded system makers, by seeing what their needs are and what technologies they use. It will also be an opportunity to meet well known members of the technical community. In particular, here are a few well know people who are going to speak at the congress:

Don’t hesitate to contact us if you are attending this event too and are interested in knowing Free Electrons better, for business, partnership or even career opportunities!

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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

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.

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Free Electrons 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 Free Electrons contributed to this kernel: with 121 patches merged in 3.13 on a total of 12127 patches contributed, Free Electrons 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 Free Electrons are:

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