Hi,

The Atmel Linux team is pleased to start this new monthly newsletter. We will present you the major events in the Open Source Community around the Atmel products. Linux-based systems on Atmel Microprocessors will certainly be the core of our coverage, but we will obviously talk about connectivity or security and the great Atmel products that are supported by Linux.

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Table of contents:

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2015 H1 Linux marking facts

As we missed several highlights from earlier this year, let's catch-up with a few marking facts:

• all Atmel MPUs are fully ported to the Device Tree infrastructure
  and all old fashioned board files removed since kernel 3.19:
  http://www.linaro.org/blog/core-dump/arm-soc-contents-merged-3-19/
• huge cleanup actions on the mach-at91/ directory during the 3.19-4.0-4.1 development phases: less code => less bugs
• sama5d4 SoC and its boards are integrated in Linux mainline with all its predecessors
• Linux 3.18 (parent of our current Linux4SAM branch) is tagged as Long Term Support kernel. It means that it will be maintained for two more years than the usual cycle (~1year).
  https://lwn.net/Articles/636289/
  As said in the links, its support will last until beginning of 2017.
• new LCD driver based on standard DRM/KMS sub-system
  http://cgit.freedesktop.org/~airlied/linux/commit/?h=drm-next&id=1a396789f65a22711eecddc5c13c0dec6bd753c7
  Support for this driver included in libdrm the user space library:
  http://lists.freedesktop.org/archives/xorg-announce/2015-June/002617.html
  
• as part of the secure boot chain, AT91Bootstrap now allows to boot a signed and AES ciphered binary (U-Boot for instance) using the hardware AES accelerator:
  https://github.com/linux4sam/at91bootstrap/commit/ef803bb363d95f44233adb7592ce43620f55916f
  This feature, with the inclusion of the sama5d3-cmp board and other enhancements are part of the new v3.7.2 AT91Bootstrap release (May 2015).
• the U-Boot used for Linux4SAM deliveries is based on v2015.01 release while many patches were submitted and accepted in U-Boot mainline making this cutting edge version suitable for all of our products.
• Xenomai the dual-kernel solution for real-time Linux is now ported and maintained on SAMA5D3 SoC
• Ethernet driver for the venerable at91rm9200 is merged in the generic "macb" driver that we use for other Atmel SoCs. It factorizes code and eases maintenance.

Linux kernel 4.1

We had a kernel release in June, so let's have a look at the additions on the Atmel's side:

• after months of cleanup and rationalization of the AT91 core code by Alexandre and Boris, helped by nice developers from the AT91 community, we managed to reach our goal: entering the "single zImage club"!
  https://plus.google.com/+FreeElectronsDevelopers/posts/XR3X275KDD9
• new LCD DRM driver mentioned above is now instantiated in products' Device Trees that embed this LCD IP
• sama5d4 Xplained board is added
• serial driver + DMA fixes
• big power management enhancement which aligns the mainline with our Linux4SAM PM code (mainly for ARMv7 SoCs). Suspend/resume is more stable and some drivers like USB or LCD are better supported now.
• several fixes for our hardware cryptography peripherals and handling of the new IP versions for SHA and AES

Also some general highlights for this important release of the Linux kernel:

• Linux 4.1 is elected as LTS for 2015 by Greg Kroah-Hartman
  https://twitter.com/LinuxLTSI/status/606321352815972354
• the Long Term Support for Industry (LTSI) project will keep on maintaining it for a couple of more years
  http://ltsi.linuxfoundation.org/
• we don't want to oversell this version of the kernel but it will probably be the next Linux4SAM master branch. We will switch to it later this year.

New Linux official co-maintainer

After many years of collaboration with Free Electrons and a huge cleanup work on drivers as well as core code for Atmel products, it was time for Alexandre to become our new co-maintainer:
https://lkml.org/lkml/2015/4/29/163

Welcome on board Alexandre!
http://free-electrons.com/blog/alexandre-belloni-atmel-co-maintainer-linux-kernel/

Linux4SAM demo version 4.7

After several months of work on the different components of our Linux-based distribution, we took the decision to release Linux4SAM 4.7.
It comes with an update of the associated linux4sam.org website. Let's see together what the highlights of this release are before that you rush on your preferred board's demo!

• Linux4SAM website pages are now classified per evaluation board. So you can have direct access to the information for the product that you are interested in.
• component updates:
  • AT91Bootstrap 3.7.2
  • the U-Boot bootloader based on the 2015.01 release
  • Linux kernel based on the 3.18 release
  • a Yocto Project root filesystem based on the version 1.7.x named "dizzy"
  • use of the full featured graphic library QT 5.4.1
• demos & pre-built binaries provided for sama5d3 EK, sama5d3 Xplained, sama5d4 EK and sama5d4 Xplained boards.
• Several screen variants usually shipped with the boards are also supported. HDMI output supported.
• Atmel WiFi chip wilc1000 can be used "out of the box": driver & firmware included in each demo.
• all Atmel MPU products are obviously kept available in each component's source code, ready to be generated and used.

Wilc1000 WiFi driver in Linux mainline

During a week at the end of April, Johnny and Tony from the SmartConnect Wi-Fi team came to Rousset to meet a part of the Atmel OS team in order to bootstrap the wilc1000 mainlining process. This work was fruitful as the driver is now officially included in the "staging" area of the 4.1 Linux kernel. It can mature there before being accepted as a genuine wireless Linux driver.

For sure, work has to be done to make it happen but since its inclusion in Greg Kroah-Hartman's staging git tree, it received more than 70 patches from Linux kernel gurus. So many enhancements that already allow the code to evolve toward the Linux kernel standards.

Buildroot: Updated Atmel boards configuration

Most of the Atmel MPU boards have updated configuration files. Even if it was pretty easy to build a filesystem in buildroot for any ARM-based board, the addition of dedicated configuration file for more Atmel boards streamlines the process:
http://lists.busybox.net/pipermail/buildroot/2015-May/128558.html

DMA drivers: lots of enhancements

Ludovic, Cyrille and Maxime (from Free Electrons) worked on our DMA drivers: at_hdmac and at_xdmac. They fixed some remaining bugs and added some nice new features. This places our DMA drivers among the most robusts and full-featured that are in mainline Linux:

• fixes for residue computation, locks & slave configuration
• enhancement of transfer data width setup
• new features added to both of our DMA drivers: memcpy interleaved and memset.
  very handy for accelerating graphical object manipulation.
  http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/346779.html
  http://www.spinics.net/lists/dmaengine/msg04457.html

Activity on linux-arm-kernel mailing-list

Linux-arm-kernel is the mailing-list where the hard work on mainline kernel code takes place. We monitor this high traffic mailing-list every day and post all of our patches there.
All of our competitors are there as well and we frequently work together to tackle an issue on a driver or add a new feature to a sub-system: this is the beauty of Linux community...
So, here is a little summary of the main topics that we had to deal with in June. We'll try to keep you informed about all these discussions on a monthly basis.

• use of stdout-path for console output on all the boards
• addition of ACME Systems' Arietta G25 board
  (http://acmesystems.it/arietta)
• support for new features in I2C, SPI or USART IPs (FIFO, DMA, HW flow control, etc.)
• new flexcom driver: discussion ongoing
• new pincontrol/pinmux driver: discussion ongoing for the use of generic pinctrl
• new PMC features added: generated clock
• finally: all our pull-requests for the upcoming Linux kernel 4.2 are merged: you'll benefit from them when kernel 4.2 is released:
  planned for the end of August: stay tuned!
  http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/352637.html

We hope that the reading of this first monthly newsletter have been fruitful and that you've enjoyed it. Please give feedback so that we can enhance it.

Bye,

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Nicolas Ferre and the whole MPU OS team