X-Git-Url: https://git.rohieb.name/openwrt.git/blobdiff_plain/b9883aef07a63590217f00afe74f586c8ea78e26..a06c10f694bec053836beeb1974e3a635e36153e:/docs/build.tex?ds=inline

diff --git a/docs/build.tex b/docs/build.tex
index 0449c08c7..03bd1a967 100644
--- a/docs/build.tex
+++ b/docs/build.tex
@@ -39,17 +39,17 @@ with the latest compilers, latest kernels and latest applications.
 So let's take a look at OpenWrt and see how this all works.
 
 
-\subsubsection{Download openwrt}
+\subsubsection{Download OpenWrt}
 
 This article refers to the "Kamikaze" branch of OpenWrt, which can be downloaded via
 subversion using the following command:
 
 \begin{Verbatim}
-$ svn co https://svn.openwrt.org/openwrt/trunk kamikaze
+$ svn checkout https://svn.openwrt.org/openwrt/trunk kamikaze
 \end{Verbatim}
 
-Additionally, ther is a trac interface on \href{https://dev.openwrt.org/}{https://dev.openwrt.org/}
-which can be used to monitor svn commits and browse the sources.
+Additionally, there is a trac interface on \href{https://dev.openwrt.org/}{https://dev.openwrt.org/}
+which can be used to monitor svn commits and browse the source repository.
 
 
 \subsubsection{The directory structure}
@@ -83,7 +83,7 @@ features or removed to save space. Note that packages are also maintained outsid
 trunk and can be obtained from subversion at the following location:
 
 \begin{Verbatim}
-$ svn co https://svn.openwrt.org/openwrt/packages ../packages
+$ svn checkout https://svn.openwrt.org/openwrt/packages packages
 \end{Verbatim}
 
 Those packages can be used to extend the functionality of the build system and need to be
@@ -96,17 +96,16 @@ kamikaze  packages
 $ ln -s packages/net/nmap kamikaze/package/nmap
 \end{Verbatim}
 
-To include all packages, issue the following command :
+To include all packages, issue the following command:
 
 \begin{Verbatim}
 $ ln -s packages/*/* kamikaze/package/
 \end{Verbatim}
 
-
 \texttt{target} refers to the embedded platform, this contains items which are specific to
 a specific embedded platform. Of particular interest here is the "\texttt{target/linux}"
-directory which is broken down by platform and contains the kernel config and patches
-to the kernel for a particular platform. There's also the "\texttt{target/image}" directory
+directory which is broken down by platform \textit{<arch>} and contains the patches to the
+kernel, profile config, for a particular platform. There's also the "\texttt{target/image}" directory
 which describes how to package a firmware for a specific platform.
 
 Both the target and package steps will use the directory "\texttt{build\_\textit{<arch>}}"
@@ -143,7 +142,15 @@ Similar to the linux kernel config, almost every option has three choices,
 \end{itemize}
 
 After you've finished with the menu configuration, exit and when prompted, save your
-configuration changes. To begin compiling the firmware, type "\texttt{make}". By default
+configuration changes.
+
+If you want, you can also modify the kernel config for the selected target system.
+simply run "\texttt{make kernel\_menuconfig}" and the build system will unpack the kernel sources
+(if necessary), run menuconfig inside of the kernel tree, and then copy the kernel config
+to \texttt{target/linux/\textit{<platform>}/config} so that it is preserved over
+"\texttt{make clean}" calls.
+
+To begin compiling the firmware, type "\texttt{make}". By default
 OpenWrt will only display a high level overview of the compile process and not each individual
 command.
 
@@ -178,7 +185,7 @@ in OpenWrt you'll find two things:
 \begin{itemize}
     \item \texttt{package/\textit{<name>}/Makefile}
     \item \texttt{package/\textit{<name>}/patches}
-	\item \texttt{package/\textit{<name>}/files}
+    \item \texttt{package/\textit{<name>}/files}
 \end{itemize}
 
 The patches directory is optional and typically contains bug fixes or optimizations to
@@ -291,7 +298,7 @@ directly as the Nth argument to \texttt{BuildPackage}.
         \item \texttt{SECTION} \\
             The type of package (currently unused)
         \item \texttt{CATEGORY} \\
-            Which menu it appears in menuconfig : Network, Sound, Utilities, Multimedia ...
+            Which menu it appears in menuconfig: Network, Sound, Utilities, Multimedia ...
         \item \texttt{TITLE} \\
             A short description of the package
         \item \texttt{URL} \\
@@ -299,7 +306,9 @@ directly as the Nth argument to \texttt{BuildPackage}.
         \item \texttt{MAINTAINER} (optional) \\
             Who to contact concerning the package
         \item \texttt{DEPENDS} (optional) \\
-            Which packages must be built/installed before this package. To reference a dependency defined in the same Makefile, use \textit{<dependency name>}. If defined as an external package, use \textit{+<dependency name>}. For a kernel version dependency use: \textit{@LINUX\_2\_<minor version>}
+            Which packages must be built/installed before this package. To reference a dependency defined in the
+			same Makefile, use \textit{<dependency name>}. If defined as an external package, use 
+			\textit{+<dependency name>}. For a kernel version dependency use: \textit{@LINUX\_2\_<minor version>}
     \end{itemize}
 
 \textbf{\texttt{Package/\textit{<name>}/conffiles} (optional):} \\
@@ -313,10 +322,29 @@ directly as the Nth argument to \texttt{BuildPackage}.
    You can leave this undefined if the source doesn't use configure or has a
    normal config script, otherwise you can put your own commands here or use
    "\texttt{\$(call Build/Configure/Default,\textit{<first list of arguments, second list>})}" as above to
-   pass in additional arguments for a standard configure script. The first list of arguments will be passed to the configure script like that : $--arg 1$ $--arg 2$. The second list contains arguments that should be defined before running the configure script such as autoconf or compiler specific variables.
+   pass in additional arguments for a standard configure script. The first list of arguments will be passed
+   to the configure script like that: \texttt{--arg 1} \texttt{--arg 2}. The second list contains arguments that should be
+   defined before running the configure script such as autoconf or compiler specific variables.
+   
+   To make it easier to modify the configure command line, you can either extend or completely override the following variables:
+   \begin{itemize}
+     \item \texttt{CONFIGURE\_ARGS} \\
+	     Contains all command line arguments (format: \texttt{--arg 1} \texttt{--arg 2})
+     \item \texttt{CONFIGURE\_VARS} \\
+	     Contains all environment variables that are passed to ./configure (format: \texttt{NAME="value"})
+   \end{itemize}
 
 \textbf{\texttt{Build/Compile} (optional):} \\
    How to compile the source; in most cases you should leave this undefined.
+   
+   As with \texttt{Build/Configure} there are two variables that allow you to override
+   the make command line environment variables and flags:
+   \begin{itemize}
+     \item \texttt{MAKE\_FLAGS} \\
+	   Contains all command line arguments (typically variable overrides like \texttt{NAME="value"}
+	 \item \texttt{MAKE\_VARS} \\
+	   Contains all environment variables that are passed to the make command
+   \end{itemize}
 
 \textbf{\texttt{Package/\textit{<name>}/install}:} \\
    A set of commands to copy files out of the compiled source and into the ipkg
@@ -345,6 +373,59 @@ After you have created your \texttt{package/\textit{<name>}/Makefile}, the new p
 will automatically show in the menu the next time you run "make menuconfig" and if selected
 will be built automatically the next time "\texttt{make}" is run.
 
+\subsection{Creating kernel modules packages}
+
+The OpenWrt distribution makes the distinction between two kind of kernel modules, those coming along with the mainline kernel, and the others available as a separate project. We will see later that a common template is used for both of them.
+
+For kernel modules that are part of the mainline kernel source, the makefiles are located in \textit{package/kernel/modules/*.mk} and they appear under the section "Kernel modules"
+
+For external kernel modules, you can add them to the build system just like if they were software packages by defining a KernelPackage section in the package makefile.
+
+Here for instance the Makefile for the I2C subsytem kernel modules :
+
+\begin{Verbatim}[frame=single,numbers=left]
+#
+# Copyright (C) 2006 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+# $Id $
+
+I2CMENU:=I2C Bus
+
+define KernelPackage/i2c-core
+  TITLE:=I2C support
+  DESCRIPTION:=Kernel modules for i2c support
+  SUBMENU:=$(I2CMENU)
+  KCONFIG:=$(CONFIG_I2C_CORE) \
+        $(CONFIG_I2C_DEV)
+  FILES:=$(MODULES_DIR)/kernel/drivers/i2c/*.$(LINUX_KMOD_SUFFIX)
+  AUTOLOAD:=$(call AutoLoad,50,i2c-core i2c-dev)
+endef
+$(eval $(call KernelPackage,i2c-core))
+\end{Verbatim}
+
+To group kernel modules under a common description in menuconfig, you might want to define a \textit{<description>MENU} variable on top of the kernel modules makefile.
+
+\begin{itemize}
+    \item \texttt{TITLE} \\
+        The name of the module as seen via menuconfig
+    \item \texttt{DESCRIPTION} \\
+        The description as seen via help in menuconfig
+    \item \texttt{SUBMENU} \\
+        The sub menu under which this package will be seen
+    \item \texttt{KCONFIG} \\
+        Kernel configuration option dependency. For external modules, remove it.
+    \item \texttt{FILES} \\
+        Files you want to inlude to this kernel module package, separate with spaces.
+    \item \texttt{AUTOLOAD} \\
+        Modules that will be loaded automatically on boot, the order you write them is the order they would be loaded.
+\end{itemize}
+
+After you have created your \texttt{package/kernel/modules/\textit{<name>}.mk}, the new kernel modules package
+will automatically show in the menu under "Kernel modules" next time you run "make menuconfig" and if selected
+will be built automatically the next time "\texttt{make}" is run.
 
 \subsection{Conventions}
 
