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<h1>OpenWrt Buildroot</h1>
</div>
- <p>Usage and documentation by Felix Fietkau, based on uClibc Buildroot
+ <p>Usage and documentation by Felix Fietkau and Waldemar Brodkorb, based on uClibc Buildroot
documentation by Thomas Petazzoni. Contributions from Karsten Kruse,
- Ned Ludd, Martin Herren.</p>
+ Ned Ludd, Martin Herren. OpenWrt Kernel Module Creation Howto by Markus Becker.</p>
<p><small>Last modification : $Id$</small></p>
<li><a href="#downloaded_packages">Location of downloaded packages</a></li>
<li><a href="#add_software">Extending OpenWrt with more Software</a></li>
<li><a href="#links">Ressources</a></li>
+<br>
+ <li><a href="#about_module">About OpenWrt Kernel Module Compilation</a></li>
+ <li><a href="#kernel">Enable the kernel options</a></li>
+ <li><a href="#buildroot_option">Create a buildroot option</a></li>
+ <li><a href="#binary">Define the binary files for the kernel module</a></li>
+ <li><a href="#control">Specify the ipkg control file</a></li>
+ <li><a href="#compile">Compile the kernel module</a></li>
+
</ul>
<h2><a name="about" id="about"></a>About OpenWrt Buildroot</h2>
<code>gcc</code>, <code>binutils</code>, uClibc and all the tools by hand.
Of course, doing so is possible. But dealing with all configure options,
with all problems of every <code>gcc</code> or <code>binutils</code>
- version it very time-consuming and uninteresting. OpenWrt Buildroot automates this
+ version is very time-consuming and uninteresting. OpenWrt Buildroot automates this
process through the use of Makefiles, and has a collection of patches for
each <code>gcc</code> and <code>binutils</code> version to make them work
- on the MIPS architecture of most Broadcom based Wireless Routers.</p>
+ on the MIPS architecture of most Wireless Routers.</p>
<h2><a name="download" id="download"></a>Obtaining OpenWrt Buildroot</h2>
- <p>OpenWrt Buildroot is currently available as experimental snapshots</p>
-
- <p>The latest snapshot is always available at <a
- href="http://openwrt.org/downloads/experimental/">http://openwrt.org/downloads/experimental/</a>,
+ <p>OpenWrt Buildroot is available via SVN aka subversion.
+ For any kind of OpenWrt development you should get the latest version from svn via:</p>
+<pre>
+ $ svn co https://svn.openwrt.org/openwrt/trunk/
+</pre>
+ <p>If you only like to create your own custom firmware images and packages we
+ strongly suggest to use the SVN branch of the stable version (whiterussian):
+ </p>
+<pre>
+ $ svn co https://svn.openwrt.org/openwrt/branches/whiterussian/
+</pre>
+
<h2><a name="using" id="using"></a>Using OpenWrt Buildroot</h2>
<li>squashfs</li>
</ul>
<p><code>jffs2</code> contains a writable root filesystem, which will expand to
- the size of your flash image. Note that you if you use the generic firmware
- Image, you need to pick the right image for your Flash size, because of different
+ the size of your flash image. Note: if you use the generic firmware image, you
+ need to pick the right image for your flash size, because of different
eraseblock sizes.</p>
<p><code>squashfs</code> contains a read-only root filesystem using a modified
tools or packages, these changes will be lost.</li>
<li>Customize the target filesystem skeleton, available under
- <code>target/default/target_skeleton/</code>. You can customize
+ <code>package/base-files/default/</code>. You can customize
configuration files or other stuff here. However, the full file hierarchy
is not yet present, because it's created during the compilation process.
So you can't do everything on this target filesystem skeleton, but
configuration, and the latter is used if you have selected
locale support.</li>
- <li>Run the compilation again</li>
+ <li>Run the compilation again.</li>
</ol>
<li><b>target</b> (in the <code>target</code> directory) contains the
Makefiles and associated files for software related to the generation of
- the target root filesystem image. Two types of filesystems are supported
+ the target root filesystem image and the linux kernel for the different
+ system on a chip boards, used in the Wireless Routers.
+ Two types of filesystems are supported
: jffs2 and squashfs.
</ul>
<li>Create the target directory (<code>build_ARCH/root/</code> by
default) and the target filesystem skeleton. This directory will contain
- the final root filesystem. To setup it up, it first deletes it, then it
+ the final root filesystem. To set it up, it first deletes it, then it
copies the skeleton available in <code>target/default/target_skeleton</code>
- and then removes useless <code>CVS/</code> directories.</li>
+ and then removes useless <code>SVN/</code> directories.</li>
<li>Call the <code>prepare</code>, <code>compile</code> and <code>install</code>
targets for the subdirectories <code>toolchain</code>, <code>package</code>
<p>For example, you may add the following to your
<code>.bashrc</code> (considering you're building for the MIPS
architecture and that Buildroot is located in
- <code>~/buildroot/</code>) :</p>
+ <code>~/openwrt/</code>) :</p>
<pre>
-export PATH=$PATH:~/buildroot/staging_dir_mipsel/bin/
+export PATH=$PATH:~/openwrt/staging_dir_mipsel/bin/
</pre>
<p>Then you can simply do :</p>
downloaded by the <i>Makefiles</i> are all stored in the
<code>DL_DIR</code> which by default is the <code>dl</code>
directory. It's useful for example if you want to keep a complete
- version of Buildroot which is know to be working with the
+ version of Buildroot which is known to be working with the
associated tarballs. This will allow you to regenerate the
toolchain and the target filesystem with exactly the same
versions.</p>
<pre>
config BR2_PACKAGE_FOO
- tristate "foo"
- default n
+ tristate "foo - some nice tool"
+ default m if CONFIG_DEVEL
help
This is a comment that explains what foo is.
</pre>
+ <p>If you depend on other software or library inside the Buildroot, it
+ is important that you automatically select these packages in your
+ <code>Config.in</code>. Example if foo depends on bar library:
+ </p>
+<pre>
+config BR2_PACKAGE_FOO
+ tristate "foo - some nice tool"
+ default m if CONFIG_DEVEL
+ select BR2_PACKAGE_LIBBAR
+ help
+ This is a comment that explains what foo is.
+</pre>
+
<p>Of course, you can add other options to configure particular
things in your software.</p>
+ <h3><code>Config.in</code> in the package directory</h3>
+
+ <p>To add your package to the configuration tool, you need
+ to add the following line to <code>package/Config.in</code>,
+ please add it to a section, which fits the purpose of foo:
+
+<pre>
+comment "Networking"
+source "package/foo/Config.in"
+</pre>
+
<h3><code>Makefile</code> in the package directory</h3>
<p>To add your package to the build process, you need to edit
<p>As you can see, this short line simply adds the target
<code>foo</code> to the list of targets handled by OpenWrt Buildroot.</p>
-
- <p>In addition to the default dependencies, you make your package
- depend on another package (e.g. a library) by adding a line:
+ <p>In addition to the default dependencies, you make your package
+ depend on another package (e.g. a library) by adding a line:
<pre>
foo-compile: bar-compile
</pre>
- <h3>The <i>.control</i> file</h3>
+ <h3>The ipkg control file</h3>
<p>Additionally, you need to create a control file which contains
information about your package, readable by the <i>ipkg</i> package
- utility.</p>
+ utility. It should be created as file:
+ <code>package/foo/ipkg/foo.control</code></p>
<p>The file looks like this</p>
3 Section: net
4 Maintainer: Foo Software <foo@foosoftware.com>
5 Source: http://foosoftware.com
- 6 Description: Your Package Description
+ 6 Depends: libbar
+ 7 Description: Package Description
</pre>
<p>You can skip the usual <code>Version:</code> and <code>Architecture</code>
fields, as they will be generated by the <code>make-ipkg-dir.sh</code> script
- called from your Makefile</p>
+ called from your Makefile. The Depends field is important, so that ipkg will
+ automatically fetch all dependend software on your target system.</p>
<h3>The real <i>Makefile</i></h3>
<p>Finally, here's the hardest part. Create a file named
<code>Makefile</code>. It will contain the <i>Makefile</i> rules that
are in charge of downloading, configuring, compiling and installing
- the software. Below is an example that we will comment
- afterwards.</p>
+ the software. Below is an example that we will comment afterwards.</p>
<pre>
1 # $Id$
- 2
- 3 PKG_NAME:=foo
- 4 PKG_VERSION:=1.0
- 5 PKG_RELEASE:=1
- 6 PKG_MD5SUM:=4584f226523776a3cdd2fb6f8212ba8d
- 7
- 8 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
- 9 PKG_SOURCE_URL:=http://www.foosoftware.org/downloads
- 10 PKG_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
- 11 PKG_IPK:=$(PACKAGE_DIR)/$(PKG_NAME)_$(PKG_VERSION)-$(PKG_RELEASE)_$(ARCH).ipk
- 12 PKG_IPK_DIR:=$(PKG_DIR)/ipkg
- 13
- 14 $(DL_DIR)/$(PKG_SOURCE):
- 15 $(SCRIPT_DIR)/download.pl $(DL_DIR) $(PKG_SOURCE) $(PKG_MD5SUM) $(PKG_SOURCE_URL)
+ 2
+ 3 include $(TOPDIR)/rules.mk
+ 4
+ 5 PKG_NAME:=foo
+ 6 PKG_VERSION:=1.0
+ 7 PKG_RELEASE:=1
+ 8 PKG_MD5SUM:=4584f226523776a3cdd2fb6f8212ba8d
+ 9
+ 10 PKG_SOURCE_URL:=http://www.foosoftware.org/downloads
+ 11 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+ 12 PKG_CAT:=zcat
+ 13
+ 14 PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
+ 15 PKG_INSTALL_DIR:=$(PKG_BUILD_DIR)/ipkg-install
16
- 17 $(PKG_DIR)/.source: $(DL_DIR)/$(PKG_SOURCE)
- 18 zcat $(DL_DIR)/$(PKG_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) -
- 19 touch $(PKG_DIR)/.source
+ 17 include $(TOPDIR)/package/rules.mk
+ 18
+ 19 $(eval $(call PKG_template,FOO,foo,$(PKG_VERSION)-$(PKG_RELEASE),$(ARCH)))
20
- 21 $(PKG_DIR)/.configured: $(PKG_DIR)/.source
- 22 (cd $(PKG_DIR); \
+ 21 $(PKG_BUILD_DIR)/.configured: $(PKG_BUILD_DIR)/.prepared
+ 22 (cd $(PKG_BUILD_DIR); \
23 $(TARGET_CONFIGURE_OPTS) \
24 CFLAGS="$(TARGET_CFLAGS)" \
25 ./configure \
28 --build=$(GNU_HOST_NAME) \
29 --prefix=/usr \
30 --sysconfdir=/etc \
- 31 );
- 32 touch $(PKG_DIR)/.configured;
- 33
- 34 $(PKG_DIR)/$(PKG_NAME): $(PKG_DIR)/.configured
- 35 $(MAKE) CC=$(TARGET_CC) -C $(PKG_DIR)
- 36
- 37 $(PKG_IPK): $(PKG_DIR)/$(PKG_NAME)
- 38 $(SCRIPT_DIR)/make-ipkg-dir.sh $(PKG_IPK_DIR) $(PKG_NAME).control $(PKG_VERSION)-$(PKG_RELEASE) $(ARCH)
- 39 $(MAKE) prefix=$(PKG_IPK_DIR)/usr -C $(PKG_DIR) install
- 40 rm -Rf $(PKG_IPK_DIR)/usr/man
- 41 $(IPKG_BUILD) $(PKG_IPK_DIR) $(PACKAGE_DIR)
- 42
- 43 $(IPKG_STATE_DIR)/info/$(PKG_NAME).list: $(PKG_IPK)
- 44 $(IPKG) install $(PKG_IPK)
- 45
- 46 prepare: $(PKG_DIR)/.source
- 47 compile: $(PKG_IPK)
- 48 install: $(IPKG_STATE_DIR)/info/$(PKG_NAME).list
- 49 clean:
- 50 rm -rf $(PKG_DIR)
- 51 rm -f $(PKG_IPK)
+ 31 --with-bar="$(STAGING_DIR)/usr" \
+ 32 );
+ 33 touch $@
+ 34
+ 35 $(PKG_BUILD_DIR)/.built:
+ 36 rm -rf $(PKG_INSTALL_DIR)
+ 37 mkdir -p $(PKG_INSTALL_DIR)
+ 38 $(MAKE) -C $(PKG_BUILD_DIR) \
+ 39 $(TARGET_CONFIGURE_OPTS) \
+ 40 install_prefix="$(PKG_INSTALL_DIR)" \
+ 41 all install
+ 42 touch $@
+ 43
+ 44 $(IPKG_FOO):
+ 46 install -d -m0755 $(IDIR_FOO)/usr/sbin
+ 47 cp -fpR $(PKG_INSTALL_DIR)/usr/sbin/foo $(IDIR_FOO)/usr/sbin
+ 49 $(RSTRIP) $(IDIR_FOO)
+ 50 $(IPKG_BUILD) $(IDIR_FOO) $(PACKAGE_DIR)
+ 51
+ 52 mostlyclean:
+ 53 make -C $(PKG_BUILD_DIR) clean
+ 54 rm $(PKG_BUILD_DIR)/.built
</pre>
<p>First of all, this <i>Makefile</i> example works for a single
binary software. For other software such as libraries or more
complex stuff with multiple binaries, it should be adapted. Look at
- the other <code>Makefile</code> files in the <code>package</code>
+ the other <code>Makefile</code> files in the <code>package/</code>
directory.</p>
- <p>At lines 3-12, a couple of useful variables are defined :</p>
+ <p>At lines 5-15, a couple of useful variables are defined:</p>
<ul>
<li><code>PKG_NAME</code> : The package name, e.g. <i>foo</i>.</li>
should be downloaded.</li>
<li><code>PKG_RELEASE</code> : The release number that will be
- appended to the version number of your <i>ipkg</i> package.
+ appended to the version number of your <i>ipkg</i> package.</li>
- <li><code>PKG_MD5SUM</code> : The md5sum of the software archive.
-
- <li><code>PKG_SOURCE</code> : The name of the tarball of
- your package on the download website of FTP site. As you can see
- <code>PKG_NAME</code> and <code>PKG_VERSION</code> are used.</li>
+ <li><code>PKG_MD5SUM</code> : The md5sum of the software archive.</li>
<li><code>PKG_SOURCE_URL</code> : Space separated list of the HTTP
or FTP sites from which the archive is downloaded. It must include the complete
path to the directory where <code>FOO_SOURCE</code> can be
found.</li>
- <li><code>PKG_DIR</code> : The directory into which the software
+ <li><code>PKG_SOURCE</code> : The name of the tarball of
+ your package on the download website of FTP site. As you can see
+ <code>PKG_NAME</code> and <code>PKG_VERSION</code> are used.</li>
+
+ <li><code>PKG_CAT</code> : The tool needed for extraction of the
+ software archive.</li>
+
+ <li><code>PKG_BUILD_DIR</code> : The directory into which the software
will be configured and compiled. Basically, it's a subdirectory
- of <code>BUILD_DIR</code> which is created upon decompression of
+ of <code>BUILD_DIR</code> which is created upon extraction of
the tarball.</li>
- <li><code>PKG_IPK</code> : The resulting <i>ipkg</i> package
+ <li><code>PKG_INSTALL_DIR</code> : The directory into the software
+ will be installed. It is a subdirectory of <code>PKG_BUILD_DIR</code>.</li>
</ul>
- <p>Lines 14-15 defines a target that downloads the tarball from
- the remote site to the download directory
- (<code>DL_DIR</code>).</p>
-
- <p>Lines 17-19 defines a target and associated rules that
- uncompress the downloaded tarball. As you can see, this target
- depends on the tarball file, so that the previous target (line
- 14-15) is called before executing the rules of the current
- target. Uncompressing is followed by <i>touching</i> a hidden file
- to mark the software has having been uncompressed. This trick is
- used everywhere in Buildroot <i>Makefile</i> to split steps
- (download, uncompress, configure, compile, install) while still
- having correct dependencies.</p>
-
- <p>Lines 21-32 defines a target and associated rules that
+ <p>In Line 3 and 17 we include common variables and routines to simplify
+ the process of ipkg creation. It includes routines to download, verify
+ and extract the software package archives.</p>
+
+ <p>Line 19 contains the magic line which automatically creates the
+ ipkg for us.</p>
+
+ <p>Lines 21-33 defines a target and associated rules that
configures the software. It depends on the previous target (the
- hidden <code>.source</code> file) so that we are sure the software has
+ hidden <code>.prepared</code> file) so that we are sure the software has
been uncompressed. In order to configure it, it basically runs the
well-known <code>./configure</code>script. As we may be doing
cross-compilation, <code>target</code>, <code>host</code> and
filesystem. Finally it creates a <code>.configured</code> file to
mark the software as configured.</p>
- <p>Lines 34-35 defines a target and a rule that compiles the
+ <p>Lines 35-42 defines a target and a rule that compiles the
software. This target will create the binary file in the
compilation directory, and depends on the software being already
configured (hence the reference to the <code>.configured</code>
- file). It basically runs <code>make</code> inside the source
- directory.</p>
-
- <p>Lines 37-41 defines a target and associated rules that create
- the <i>ipkg</i> package which can optionally be embedded into
- the resulting firmware image. It depends on the binary file in
- the source directory, to make sure the software has been compiled.
- It uses the make-ipkg-dir.sh script, which will create the ipkg
- build directory for your package, copy your control file into
- that directory and add version and architecture information.
- Then it calls the <code>install</code> target of the
- software <code>Makefile</code> by passing a <code>prefix</code>
- argument, so that the <code>Makefile</code> doesn't try to install
- the software inside host <code>/usr</code> but inside target
- <code>/usr</code>. After the installation, the
- <code>/usr/man</code> directory inside the target filesystem is
- removed to save space.
+ file). Afterwards it installs the resulting binary into the
+ <code>PKG_INSTALL_DIR</code>. It basically runs
+ <code>make install</code> inside the source directory.</p>
+
+ <p>Lines 44-50 defines a target and associated rules that create
+ the <i>ipkg</i> package, which can optionally be embedded into
+ the resulting firmware image. It manually installs all files you
+ want to integrate in your resulting ipkg. <code>RSTRIP</code> will
+ recursevily strip all binaries and libraries.
Finally <code>IPKG_BUILD</code> is called to create the package.</p>
- <p>Line 43 and 44 define the installation target of your package,
- which will embed the software into the target filesystem.</p>
-
- <p>Lines 46-51 define the main targets that the Makefile in the
- <code>package</code> dir calls.
- <ul>
- <li><code>prepare</code> : Download and unpack the source</li>
- <li><code>compile</code> : Compile the source and create the package</li>
- <li><code>install</code> : Embed the package into the target filesystem</li>
- <li><code>clean</code> : Remove all the files created by the build process</li>
- </ul></p>
-
<h3>Conclusion</h3>
<p>As you can see, adding a software to buildroot is simply a
the software.</p>
<p>If you package software that might be useful for other persons,
- don't forget to send a patch to OpenWrt developers !</p>
+ don't forget to send a patch to OpenWrt developers!
+ Use the mail address: openwrt-devel@openwrt.org
+ </p>
<h2><a name="links" id="links"></a>Resources</h2>
- <p>To learn more about OpenWrt Buildroot you can visit this
- website: <a href="http://openwrt.org/">http://openwrt.org/</a></p>
+ <p>To learn more about OpenWrt you can visit this website:
+ <a href="http://openwrt.org/">http://openwrt.org/</a></p>
</div>
+
+ <div class="main">
+ <div class="titre">
+ <h1>OpenWrt Kernel Module Creation Howto</h1>
+ </div>
+
+ <h2><a name="about_module" id="about_module"></a>About OpenWrt Kernel Module Compilation</h2>
+
+ <p>You are planning to compile a kernel module? This howto will
+explain what you have to do, to have your kernel module installable as
+an ipkg.</p>
+
+ <h2><a name="kernel" id="kernel"></a>Enable the kernel options</h2>
+
+ <p>Enable the kernel options you want by modifying
+build_mipsel/linux/.config. We are assuming, that you already had your
+kernel compiled once here. You can do the modification by hand or by
+
+<pre>
+$ cd build_mipsel/linux
+$ make menuconfig
+</pre>
+
+And copy it, so your changes are not getting lost, when doing a 'make
+dirclean'. Here we assume that you are compiling for Broadcom chipset
+based devices:
+
+<pre> $ cp .config ../../../target/linux/linux-2.4/config/brcm </pre>
+
+</p>
+ <h2><a name="buildroot_option" id="buildroot_option"></a>Create a buildroot option</h2>
+
+ <p>Create a buildroot option by modifying/inserting into
+target/linux/Config.in, e.g.
+
+<pre>
+config BR2_PACKAGE_KMOD_USB_KEYBOARD
+ tristate "Support for USB keyboards"
+ default m
+ depends BR2_PACKAGE_KMOD_USB_CONTROLLER
+</pre>
+</p>
+
+ <h2><a name="binary" id="binary"></a>Define the binary files for the kernel module</h2>
+
+ <p>Define the binary files for the kernel module by modifying/inserting into
+target/linux/linux-2.4/Makefile, e.g.
+
+<pre>
+$(eval $(call KMOD_template,USB_KEYBOARD,usb-kbd,\
+ $(MODULES_DIR)/kernel/drivers/input/input.o \
+ $(MODULES_DIR)/kernel/drivers/input/keybdev.o \
+ $(MODULES_DIR)/kernel/drivers/usb/usbkbd.o \
+,CONFIG_USB_KEYB,kmod-usb-core,60,input keybdev usbkbd))
+</pre>
+
+Where CONFIG_USB_KEYB is the kernel option, USB_KEYBOARD is the last
+part of BR2_PACKAGE_KMOD_USB_KEYBOARD and usb-kbd is part of the
+filename of the created ipkg.</p>
+
+ <h2><a name="control" id="control"></a>Specify the ipkg control file</h2>
+
+ <p>Create e.g. target/linux/control/kmod-usb-kbd.control with content similar to this:
+
+<pre>
+Package: kmod-usb-kbd
+Priority: optional
+Section: sys
+Maintainer: Markus Becker <mab@comnets.uni-bremen.de>
+Source: buildroot internal
+Description: Kernel Support for USB Keyboards
+</pre>
+ </p>
+
+ <h2><a name="compile" id="compile"></a>Compile the kernel module</h2>
+
+ <p>Enable the kernel module with
+<pre>
+$ make menuconfig
+</pre>
+ in TOPDIR and selecting it.<br>
+
+ Compile with
+<pre>
+$ make dirclean && make
+</pre>
+ </p>
+ </div>
+
</body>
</html>