<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>
<h2><a name="download" id="download"></a>Obtaining OpenWrt Buildroot</h2>
<p>OpenWrt Buildroot is available via CVS - Concurrent Version System.
- For any kind of development you should get the latest version from cvs via:</p>
+ For any kind of OpenWrt development you should get the latest version from cvs via:</p>
<pre>
$ cvs -d:pserver:anonymous@openwrt.org:/openwrt co openwrt
</pre>
+ <p>If you only like to create your own custom firmware images and pakages we
+ strongely suggest to use the CVS branch of the stable version (whiterussian):
+ </p>
+<pre>
+ $ cvs -d:pserver:anonymous@openwrt.org:/openwrt co -rwhiterussian openwrt
+</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
<h2><a name="custom_targetfs" id="custom_targetfs"></a>Customizing the
target filesystem</h2>
- <p>There are two ways to customize the resulting target filesystem:</p>
-
- <ul>
- <li>Customize the target filesystem directly, and rebuild the image. The
- target filesystem is available under <code>build_ARCH/root/</code> where
- <code>ARCH</code> is the chosen target architecture, usually mipsel.
- You can simply make your changes here, and run make target_install afterwards,
- which will rebuild the target filesystem image. This method allows to do
- everything on the target filesystem, but if you decide to rebuild your toolchain,
- 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
- 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
- changes to it remains even when you completely rebuild the cross-compilation
- toolchain and the tools.<br />
- </ul>
+ <li>You can customize the target filesystem skeleton, available under
+ <code>package/base-files/default/</code>. You can change
+ 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
+ changes to it remains even when you completely rebuild the cross-compilation
+ toolchain and the tools.<br />
<h2><a name="custom_busybox" id="custom_busybox"></a>Customizing the
Busybox configuration</h2>
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>
<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 include $(TOPDIR)/rules.mk
- 3 PKG_NAME:=foo
- 4 PKG_VERSION:=1.0
- 5 PKG_RELEASE:=1
- 6 PKG_MD5SUM:=4584f226523776a3cdd2fb6f8212ba8d
- 7
- 8 PKG_SOURCE:=$(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>
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