Category: Technical

The 2010.11 release of Buildroot has been published on November, 30th. Buildroot is a tool that eases the process of building an embedded Linux system: cross-compiling toolchain, root filesystem with dozens or hundreds of libraries and applications, bootloader and kernel.

Release 2010.11

Releases are made every three months, and the latest 2010.11 release has a number of improvements :

• Experimental crosstool-NG back-end for handling the toolchain. Before, Buildroot could either compile a toolchain for you, or use an already existing external toolchain. However, the internal Buildroot process for building a toolchain is limited to uClibc and its maintenance is a duplication of the work done by the Crosstool-NG community. While this back-end is only experimental at the moment, the intention is to make it the default back-end in some future release, if everything works fine. Thanks to Yann E. Morin for implementing this back-end, and making related changes to Crosstool-NG.
• The Kconfig infrastructure has been updated to the one of 2.6.36 and has been cleaned up (we now have a nice quilt patch series). This brings savedefconfig (for minimal Buildroot configurations) and nconfig support. We now also create a convenience Makefile wrapper in the output directory for out-of-tree builds, like the kernel has. So once you have done a first make O=/some/path menuconfig, you can go into /some/path and directly use make something without having to specify the output directory.
• Old-style package hooks (*_HOOK_POST_*) have been removed. This was just a clean up process, because we have a more modern way of allowing packages to hook specific commands at various steps of the build process.
• Download handling has been reworked and support for git/svn downloads was added, so that packages only available through version control systems can be added easily in Buildroot. The make source (to download all needed tarballs and files so that the build can be done completely offline) and make external-deps (to show all files that would need to be downloaded) commands have been improved to fix several issues
• On the architecture side, support for ARM Cortex A9 and Sparc LEON variants was added. Support for Alpha, Cris, IA64 and Sparc64 (deprecated in 2010.08) was removed.
• We also added a few more packages: argp-standalone, gdk-pixbuf, gpsd, gst-ffmpeg, libmpeg2, kbd, librsvg, nuttcp, rng-tools, rrdtool and xz. And removed some deprecated packages: dillo, libglib12, libgtk12, microwin and pcmcia.
• Many, many packages have been updated. In particular, the Gtk+ library has been updated from 2.12 to 2.20, keeping the DirectFB support functional thanks to the work of Lionel Landwerlin (the DirectFB support in Gtk+ was broken since 2.12). So, finally, this brings us a recent and fresh Gtk+ library in Buildroot.
• Many packages were converted to the autotargets or gentargets infrastructures (that we use to describe how a particular package should be downloaded, extracted, configured, built and installed), in particular thanks to the work of Martin Banky.

I have again contributed quite a bit to this release, but not as much as I wanted to. Here are the numbers:

git shortlog -s -n 2010.08..
   168  Peter Korsgaard
   115  Thomas Petazzoni
    55  Gustavo Zacarias
    37  Martin Banky
    26  Yann E. MORIN
    15  Lionel Landwerlin
    13  Mike Frysinger
    10  Paulius Zaleckas
     8  Maxime Petazzoni
     4  Konrad Eisele
     3  Chih-Min Chao
     2  Yegor Yefremov
     1  Andy Gibbs
     1  Felipe Contreras
     1  Frederik Pasch
     1  Heiko Zuerker
     1  Javier Viguera
     1  Luca Ceresoli
     1  Marcelo Roberto Jimenez
     1  Marcus Osdoba
     1  Matt Johnson
     1  Paul Burton
     1  Paul Jones
     1  Stanislav Bogatyrev
     1  Thomas Rudin
     1  Will Newton

The things I worked on are: cleanup of the kconfig patches and switch to the 2.6.36 one, removal of old-style hooks and many other small package cleanups, Gtk+ upgrade and documentation improvements. I’m also very happy to see that the number of contributors is increasing, as is the number of questions asked on the list, on IRC and on the bug tracker.

Buildroot developer day

A Buildroot Developer Day, meeting of some of the Buildroot developers, took place on October, 29th in Cambridge, UK, just after the Embedded Linux Conference Europe. Peter Korsgaard (Buildroot maintainer), Lionel Landwerlin (contributor), Yann E. Morin (contributor, Crosstool-NG developer), Nicolas Ferre (Atmel), Patrice Vilchez (Atmel) and Thomas Petazzoni (Bootlin) attended the meeting.

There has been discussions about cleaning up board support, libtool issues, Crosstool-NG integration, toolchain cleanup, top-level parallel make and package management. A report has been posted to the Buildroot mailing list.

The next Buildroot Developer Day will take place on Monday, 7th February, just after FOSDEM, in Brussels.

Roadmap for 2011.02

Here are some of the things that are in the pipeline, for 2011.02 if everything goes well.

• Conversion of more (all remaining?) packages to the gentargets and autotargets infrastructures.
• Cleanup of board support in Buildroot. We will now use minimal defconfigs for both Buildroot itself and for kernel configuration. The messy target/device/ directory will be cleaned-up. And we will add support for some emulated boards based on Qemu (x86, ARM, MIPS, PowerPC, SH4). This work is already done, so it’s very likely to be in 2011.02
• Better support of devtmpfs, mdev and udev. An option will allow the user to select between static device creation and those three techniques for having a dynamic /dev. This is also ready.
• Improvements in the external toolchain configuration and setup. Buildroot will be able to automatically download some well-known external toolchains, making them easier to use.
• The Buildroot internal toolchain build process will be reworked, with conversion of most of the code to the package infrastructures, and the toolchain binaries and sysroot move to $(HOST_DIR). This will make it much, much easier to use the toolchain produced by Buildroot outside of Buildroot, and will allow us to generate a SDK to be shared with application developers, without requiring them to run Buildroot. See the report from the Buildroot Developers Day for details. This work has already been started by Gustavo Zacarias, and at least part of it will be in 2011.02.
• Package management will be improved. Buildroot will know which package installed what in the different directories, and will therefore be able to cleanly remove a package from the system if it has been disabled in the configuration, without requiring a completely clean rebuild. Later on, this work could be used to generate .ipk packages, but for the moment, the focus is on being able to remove libraries and applications from the system when they are unselected from the configuration. This work has already been started by Lionel Landwerlin, and we will do our best to merge it into 2011.02.
• Support for non-MMU architectures, and particularly Blackfin. Mike Frysinger has already posted patches to add Blackfin and support non-MMU for several packages. This is really a good news, as Buildroot is a good fit for non-MMU systems.
• Public access to regression tests results

Toolchain cleanup work and board cleanup work are really interesting pieces, because they are the two remaining parts of Buildroot that haven’t been cleaned up and/or rewritten since the Buildroot project came back to life late 2008/early 2009. There are of course still some areas that need improvements of course, but for me, those two pieces are really closing the large cleanup work that has been started almost two years ago.

Of course, don’t hesitate to contact the Buildroot mailing-list, the IRC channel or the bug tracker if you have any questions or issues in using Buildroot.