Thomas Petazzoni – Page 24

Buildroot training updated to Buildroot 2016.05

Almost exactly one year ago, we announced the availability of our training course on Buildroot. This course received very good feedback, both from our customers, and from the community.

In our effort to continuously improve and update our training materials, we have recently updated our Buildroot training course to Buildroot 2016.05, which was released at the end of May. In addition to adapting our practical labs to use this new Buildroot version, we have also improved the training materials to cover some of the new features that have been added over the last year in Buildroot. The most important changes are:

Cover the graph-size functionality, which allows to generate a pie chart of the filesystem size, per package. This is a very nice feature to analyze the size of your root filesystem and see how to reduce it.
Improve the description about the local site method and the override source directory functionalities, that are very useful when doing active application/library development in Buildroot, or to package custom application/library code.
Add explanations about using genimage to create complete SD card images that are ready to be flashed.
Add explanations about the hash file that can be added to packages to verify the integrity of the source code that is downloaded before it gets built.

The updated training materials are available on the training page: agenda (PDF), slides (PDF) and practical labs (PDF).

Contact us if you would like to organize this training session in your company: we are available to deliver it worldwide.

Linux 4.6 released, with Bootlin contributions

Adelie Penguin The 4.6 version of the Linux kernel was released last Sunday by Linus Torvalds. As usual, LWN.net had a very nice coverage of this development cycle merge window, highlighting the most significant changes and improvements: part 1, part 2 and part 3. KernelNewbies is now active again, and has a very detailed page about this release.

On a total of 13517 non-merge commits, Bootlin contributed for this release a total of 107 non-merge commits, a number slightly lower than our past contributions for previous kernel releases. That being said, there are still a few interesting contributions in those 107 patches. We are particular happy to see patches from all our eight engineers in this release, including from Mylène Josserand and Romain Perier, who just joined us mid-March! We also already have 194 patches lined-up for the next 4.7 release.

Here are the highlights of our contributions to the 4.6 release:

Atmel ARM processors support
- Alexandre Belloni and Boris Brezillon contributed a number of patches to improve and cleanup the support for the PMC (Power Management and Clocks) hardware block. As expected, this involved patching both clock drivers and power management code for the Atmel platforms.
Annapurna Labs Alpine platforms support
- As a newly appointed maintainer of the Annapurna Labs ARM/ARM64 Alpine platforms, Antoine Ténart contributed the base support for the ARM64 Alpine v2 platform: base platform support and Device Tree, and an interrupt controller driver to support MSI-X
Marvell ARM processors support
- Grégory Clement added initial support for the Armada 3700, a new Cortex-A53 based ARM64 SoC from Marvell, as well as a first development board using this SoC. So far, the supported features are: UART, USB and SATA (as well as of course timers and interrupts).
- Thomas Petazzoni added initial support for the Armada 7K/8K, a new Cortex-A72 based ARM64 SoC from Marvell, as well as a first development board using this SoC. So far, UART, I2C, SPI are supported. However, due to the lack of clock drivers, this initial support can’t be booted yet, the clock drivers and additional support is on its way to 4.7.
- Thomas Petazzoni contributed an interrupt controller driver for the ODMI interrupt controller found in the Armada 7K/8K SoC.
- Grégory Clement and Thomas Petazzoni did a few improvements to the support of Armada 38x. Thomas added support for the NAND flash used on Armada 370 DB and Armada XP DB.
- Boris Brezillon contributed a number of fixes to the Marvell CESA driver, which is used to control the cryptographic engine found in most Marvell EBU processors.
- Thomas Petazzoni contributed improvements to the irq-armada-370-xp interrupt controller driver, to use the new generic MSI infrastructure.
Allwinner ARM processors support
- Maxime Ripard contributed a few improvements to Allwinner clock drivers, and a few other fixes.
MTD and NAND flash subsystem
- As a maintainer of the NAND subsystem, Boris Brezillon did a number of contributions in this area. Most notably, he added support for the randomizer feature to the Allwinner NAND driver as well as related core NAND subsystem changes. This change is needed to support MLC NANDs on Allwinner platforms. He also contributed several patches to continue clean up and improve the NAND subsystem.
- Thomas Petazzoni fixed an issue in the pxa3xx_nand driver used on Marvell EBU platforms that prevented using some of the ECC configurations (such as 8 bits BCH ECC on 4 KB pages). He also contributed minor improvements to the generic NAND code.
Networking subsystem
- Grégory Clement contributed an extension to the core networking subsystem that allows to take advantage of hardware capable of doing HW-controlled buffer management. This new extension is used by the mvneta network driver, useful for several Marvell EBU platforms. We expect to extend this mechanism further in the future, in order to take advantage of additional hardware capabilities.
RTC subsystem
- As a maintainer of the RTC subsystem, Alexandre Belloni did a number of fixes and improvements in various RTC drivers.
- Mylène Josserand contributed a few improvements to the abx80x RTC driver.
Altera NIOSII support
- Romain Perier contributed two patches to fix issues in the kernel running on the Altera NIOSII architecture. The first one, covered in a previous blog post, fixed the NIOSII-specific memset() implementation. The other patch fixes a problem in the generic futex code.

In addition, several our of engineers are maintainers of various platforms or subsystems, so they do a lot of work reviewing and merging the contributions from other kernel developers. This effort can be measured by looking at the number of patches on which they Signed-off-by, but for which they are not the author. Here are the number of patches that our engineered Signed-off-by, but for which they were not the author:

Alexandre Belloni, as the RTC subsystem maintainer and the Atmel ARM co-maintainer: 91 patches
Maxime Ripard, as the Allwinner ARM co-maintainer: 65 patches
Grégory Clement, as the Marvell EBU ARM co-maintainer: 45 patches
Thomas Petazzoni, simply resubmitting patches from others: 2 patches

Here is the detailed list of our contributions to the 4.6 kernel release:

Article on the CHIP in French Linux magazine

Bootlin engineer and Allwinner platform maintainer Maxime Ripard has written a long article presenting the Nextthing C.H.I.P platform in issue #18 of French magazine OpenSilicium, dedicated to open source in embedded systems. The C.H.I.P has even been used for the front cover of the magazine!

OpenSilicium #18

In this article, Maxime presents the C.H.I.P platform, its history and the choice of the Allwinner SoC. He then details how to set up a developer-friendly environment to use the board, building and flashing from scratch U-Boot, the kernel and a Debian-based root filesystem. Finally, he describes how to use Device Tree overlays to describe additional peripherals connected to the board, with the traditional example of the LED.

OpenSilicium #18 CHIP article

In the same issue, OpenSilicium also covers numerous other topics:

A feedback on the FOSDEM 2016 conference
Uploading code to STM32 microcontrollers: the case of STM32-F401RE
Kernel and userspace debugging with ftrace
IoT prototyping with Buildroot
RIOT, the free operating system for the IoT world
Interview of Cedric Bail, working on the Enligthenment Foundation Libraries for Samsung
Setup of Xenomai on the Zynq Zedboard
Decompression of 3R data stream using a VHDL-described circuit
Write a userspace device driver for a FPGA using UIO

Slides from the Embedded Linux Conference

Two weeks ago, the entire Bootlin engineering team (9 persons) attended the Embedded Linux Conference in San Diego. We had some really good time there, with lots of interesting talks and useful meetings and discussions.

Tim Bird opening the conference Discussion between Linus Torvalds and Dirk Hohndel

In addition to attending the event, we also participated by giving 5 different talks on various topics, for which we are publishing the slides:

Boris Brezillon, the new NAND Linux subsystem maintainer, presented on Modernizing the NAND framework: The big picture.

Antoine Ténart presented on Using DT overlays to support the C.H.I.P’s capes.

Maxime Ripard, maintainer of the Allwinner platform support in Linux, presented on Bringing display and 3D to the C.H.I.P computer.

Alexandre Belloni and Thomas Petazzoni presented Buildroot vs. OpenEmbedded/Yocto Project: a four hands discussion.

Thomas Petazzoni presented GNU Autotools: a tutorial.

All the other slides from the conference are available from the event page as well as from eLinux.org Wiki. All conferences have been recorded, and the videos will hopefully be posted soon by the Linux Foundation.

Bootlin engineer Boris Brezillon becomes Linux NAND subsystem maintainer

Bootlin engineer Boris Brezillon has been involved in the support for NAND flashes in the Linux kernel for quite some time. He is the author of the NAND driver for the Allwinner ARM processors, did several improvements to the NAND GPMI controller driver, has initiated a significant rework of the NAND subsystem, and is working on supporting MLC NANDs. Boris is also very active on the linux-mtd mailing list by reviewing patches from others, and making suggestions.

Hynix NAND flash

For those reasons, Boris was recently appointed by the MTD maintainer Brian Norris as a new maintainer of the NAND subsystem. NAND is considered a sub-subsystem of the MTD subsystem, and as such, Boris will be sending pull requests to Brian, who in turn is sending pull requests to Linus Torvalds. See this commit for the addition of Boris as a NAND maintainer in the MAINTAINERS file. Boris will therefore be in charge of reviewing and merging all the patches touching drivers/mtd/nand/, which consist mainly of NAND drivers. Boris has created a nand/next branch on Github, where he has already merged a number of patches that will be pushed to Brian Norris during the 4.7 merge window.

We are happy to see one of our engineers taking another position as a maintainer in the kernel community. Maxime Ripard was already a co-maintainer of the Allwinner ARM platform support, Alexandre Belloni a co-maintainer of the RTC subsystem and Atmel ARM platform support, Grégory Clement a co-maintainer of the Marvell EBU platform support, and Antoine Ténart a co-maintainer of the Annapurna Labs platform support.

Slides from Collaboration Summit talk on Linux kernel upstreaming

As we announced in a previous blog post, Bootlin CTO Thomas Petazzoni gave a talk at the Collaboration Summit 2016 covering the topic of “Upstreaming hardware support in the Linux kernel: why and how?“.

The slides of the talk are now available in PDF format.

Upstreaming hardware support in the Linux kernel: why and how?

Through this talk, we identified a number of major reasons that should encourage hardware vendors to contribute the support for their hardware to the upstream Linux kernel, and some hints on how to achieve that. Of course, within a 25 minutes time slot, it was not possible to get into the details, but hopefully the general hints we have shared, based on our significant Linux kernel upstreaming experience, have been useful for the audience.

Unfortunately, none of the talks at the Collaboration Summit were recorded, so no video will be available for this talk.

Bootlin contributions to Linux 4.5

Adelie Penguin Linus Torvalds just released Linux 4.5, for which the major new features have been described by LWN.net in three articles: part 1, part 2 and part 3. On a total of 12080 commits, Bootlin contributed 121 patches, almost exactly 1% of the total. Due to its large number of contribution by patch number, Bootlin engineer Boris Brezillon appears in the statistics of top-contributors for the 4.5 kernel in the LWN.net statistics article.

This time around, our important contributions were:

Addition of a driver for the Microcrystal rv1805 RTC, by Alexandre Belloni.
A huge number of patches touching all NAND controller drivers and the MTD subsystem, from Boris Brezillon. They are the first step of a more general rework of how NAND controllers and NAND chips are handled in the Linux kernel. As Boris explains in the cover letter, his series aims at clarifying the relationship between the mtd and nand_chip structures and hiding NAND framework internals to NAND. […]. This allows removal of some of the boilerplate code done in all NAND controller drivers, but most importantly, it unifies a bit the way NAND chip structures are instantiated.
On the support for the Marvell ARM processors:
- In the mvneta networking driver (used on Armada 370, XP, 38x and soon on Armada 3700): addition of naive RSS support with per-CPU queues, configure XPS support, numerous fixes for potential race conditions.
- Fix in the Marvell CESA driver
- Misc improvements to the mv_xor driver for the Marvell XOR engines.
- After four years of development the 32-bits Marvell EBU platform support is now pretty mature and the majority of patches for this platform now are improvements of existing drivers or bug fixes rather than new hardware support. Of course, the support for the 64-bits Marvell EBU platform has just started, and will require a significant number of patches and contributions to be fully supported upstream, which is an on-going effort.
On the support for the Atmel ARM processors:
- Addition of the support for the L+G VInCo platform.
- Improvement to the macb network driver to reset the PHY using a GPIO.
- Fix Ethernet PHY issues on Atmel SAMA5D4
On the support for Allwinner ARM processors:
- Implement audio capture in the sun4i audio driver.
- Add the support for a special pin controller available on Allwinner A80.

The complete list of our contributions:

Bootlin contributing Linux kernel initial support for Annapurna Labs ARM64 Platform-on-Chip

We are happy to announce that on February 8th 2016 we submitted to the mainline Linux kernel the initial support for Annapurna Labs Alpine v2 Platform-on-Chip based on the 64-bit ARMv8 architecture.

See our patch series:

Annapurna Labs was founded in 2011 in Israel. Annapurna Labs provides 32-bit and 64-bit ARM products including chips and subsystems under the Alpine brand for the home NAS, Gateway and WiFi router equipment, see this page for details. The 32-bit version already has support in the official Linux kernel (see alpine.dtsi), and we have started to add support for the quad core 64-bit version, called Alpine v2, which brings significant performance for the home.

This is our initial contribution and we plan to follow it with additional Alpine v2 functionality in the near future.

“Porting Linux on ARM” seminar road show in France

In December 2015, Bootlin engineer Alexandre Belloni gave a half-day seminar “Porting Linux on ARM” in Toulouse (France) in partnership with french organization Captronic. We published the materials used for the seminar shortly after the event.

We are happy to announce that this seminar will be given in four different cities in France over the next few months:

In Montpellier, on April 14th from 2 PM to 6 PM. See this page for details.
In Clermont-Ferrand, on April 27th from 2 PM to 6 PM. See this page for details.
In Brive, on April 28th from 9 AM to 1 PM. See this page for details.
Near Chambéry, on May 25th from 9:30 AM to 5/30 PM. See this page for details.
Near Bordeaux, on June 2nd from 2 PM to 6 PM. See this page for details.
Near Nancy, on June 16th from 2 PM to 6 PM. See this page for details.

The seminar is delivered in French, and the event is free after registration. The speaker, Alexandre Belloni, has worked on porting botloaders and the Linux kernel on a number of ARM platforms (Atmel, Freescale, Texas Instruments and more) and is the Linux kernel co-maintainer for the RTC subsystem and the support of the Atmel ARM processors.

Bootlin at the Embedded Linux Conference 2016

Like every year for about 10 years, the entire Bootlin engineering team will participate to the next Embedded Linux Conference, taking place on April 4-6 in San Diego, California. For us, participating to such conferences is very important, as it allows to remain up to date with the latest developments in the embedded Linux world, create contacts with other members of the embedded Linux community, and meet the community members we already know and work with on a daily basis via the mailing lists or IRC.

Embedded Linux Conference 2016

Over the years, our engineering team has grown, and with the arrival of two more engineers on March 14, our engineering team now gathers 9 persons, all of whom are going to participate to the Embedded Linux Conference.

As usual, in addition to attending, we also proposed a number of talks, and some of them have been accepted and are visible in the conference schedule:

Buildroot vs. OpenEmbedded/Yocto: A Four Hands Discussion, Alexandre Belloni & Thomas Petazzoni
Using DT Overlays to Support the C.H.I.P.’s Capes, Antoine Tenart
Modernizing the NAND framework: The Big Picture, Boris Brezillon
Bringing Display and 3D to the C.H.I.P Computer, Maxime Ripard
Autotools: A Demystification Tutorial, Thomas Petazzoni

As usual, our talks are centered around our areas of expertise: hardware support in the Linux kernel, especially for ARM platforms, and build system related topics (Buildroot, Yocto, autotools).

We are looking forward to attending this event, and see many other talks from various speakers: the proposed schedule contains a wide range of topics, many of which look really interesting!