====== Compiling Linux kernel ======

===== Used versions =====

  * Ubuntu 10.04 i386 (VMware Virtual Machine)
  * ELDK 4.2

===== Preparation =====
Install the git source code management system.
<code bash>
user@ubuntu:~$ sudo apt-get install git-core stgit uboot-mkimage
</code>

Create a directory for the Linux source code:
<code bash>
tq@ubuntu:~$ mkdir ~/src
tq@ubuntu:~$ cd ~/src
</code>

==== Get source code ====
The current BSP (October 2011) is based on the 2.6.39 kernel of Denx software engineering. The base version of this source code you get from the Git server http://git.denx.de.

<code bash>
tq@ubuntu:~/src$ git clone http://git.denx.de/linux-denx.git
tq@ubuntu:~/src$ cd linux-denx
</code>

Create local branch named p2020 with the source code of version DENX-v2.6.39:
<code bash>
tq@ubuntu:~/src/linux-denx$ git checkout -b p2020 DENX-v2.6.39
</code>

==== Patch sources ====
Unpack the archive with the patches into a local folder e.g. to ''~/src/BSP/Linux/patches''.

<WRAP round info>
The directory containing the patches is on the included DVD, and on the [[http://www.tq-group.com/tqmp2020#product-downloads|TQ product page]].
</WRAP>

The patches are now applied to the kernel sources:

<code bash>
tq@ubuntu:~/src/linux-denx$ stg init
tq@ubuntu:~/src/linux-denx$ stg import -t -s ~/src/BSP/Linux/patches/series
</code>

===== Build kernel =====
If the ELDK has been 
[[en:tqmp2020:installation_eldk_toolchain#eldk_cross_compiler_configuration|configured]] 
according to the instructions the cross compilation toolchain is ready to compile the kernel.

Configure and build:
<code bash>
tq@ubuntu:~/src/linux-denx$ make 85xx/tqmp2020_defconfig
tq@ubuntu:~/src/linux-denx$ make uImage
</code>

<WRAP round info>
If the following error occurs when configuring the kernel source code:
<code>
*** Can't find default configuration "arch/x86/configs/85xx/tqmp2020_defconfig"!
</code>

then the environment is not configured correctly. For more information see section 
[[en:tqmp2020:installation_eldk_toolchain|Installation of the ELDK Toolchain]].
</WRAP>


==== Download kernel via TFTP ====

To load the kernel ''uImage'' in the directory ''arch/powerpc/boot'', it has to be copied to the [[en:tftp|TFTP]] root directory. Depending on the configuration of the [[en:tftp|TFTP]] server it is e.g. ''/tftpboot''. Starting from the source directory the ''uImage'' is copied to the ''/tftpboot'' directory with the following command.

<code bash>
tq@ubuntu:~/src/linux-denx$ cp arch/powerpc/boot/uImage /tftpboot
</code>