Grinberg: /* Building the firmware images */

2014-12-18T09:43:42Z

‎Building the firmware images

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== Overview ==
The CompuLab CM-T54 System-on-Module / Computer-on-Module firmware consists of two components: Secondary Program Loader (SPL) and U-Boot.
Both components are based on [http://www.denx.de/wiki/U-Boot/WebHome U-Boot] source code.
SPL is the bootstrap utility invoked by the CPU internal boot ROM code of the OMAP54xx SoC.
SPL performs minimal hardware initialization and loads U-Boot from the same boot device.
U-Boot initializes hardware modules necessary for system boot and loads the operating system.

== Building Firmware images for CM-T54 ==
=== Cross-Compiler ===
There are several options for cross-compilation toolchain setup. You can either compile your cross-compiler or use an already built cross-compiler. The cross-compiler should support the ARM embedded-application binary interface ("[http://en.wikipedia.org/wiki/Application_binary_interface#EABI EABI]")
* Pre-built toolchain (recommended):
** [http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/editions/lite-edition/ Sourcery CodeBench Lite]
* Tools for creating cross-compilers:
** [http://crosstool-ng.org/ Crosstool-ng]: Builds a cross-compiler from source. Non-distribution specific.
** [http://www.gentoo.org/proj/en/base/embedded/handbook/index.xml?part=1&chap=4 Crossdev]: Gentoo's cross-compiler builder. Needs Gentoo.

=== Getting U-Boot sources ===
There are two ways to get U-Boot sources that can be used as a baseline for CM-T54 SPL and U-Boot.
You can create a copy of "Das U-Boot" source tree or download a snapshot and extract it.
We assume that you have created {{filename|/home/development/cm-t54/u-boot}} directory for CM-T54 u-boot development.

==== Snapshot download ====
* Download [http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=snapshot;h=c43fd23cf619856b0763a64a6a3bcf3663058c49;sf=tgz v2014.10] snapshot with your web browser.
* Extract the downloaded archive {{filename|u-boot-c43fd23.tar.gz}}
<pre>
cd /home/development/cm-t54/u-boot
tar xvf /path/to/downloaded/u-boot-c43fd23.tar.gz
mv u-boot u-boot-cm-t54
</pre>
: This will create {{filename|/home/development/cm-t54/u-boot/u-boot-cm-t54}} directory containing U-Boot source code tree.
* Apply the CM-T54 patch
<pre>
cd /home/development/cm-t54/u-boot/u-boot-cm-t54
patch -p1 < /path/to/cm-t54-u-boot/u-boot/u-boot-v2014.10-cm-t54-2.patch
</pre>

==== Git clone ====
* Install [http://git-scm.com/ git] version control system.
* Create a clone of U-Boot tree
<pre>
cd /home/development/cm-t54/u-boot
git clone git://git.denx.de/u-boot.git u-boot-cm-t54
</pre>
* Create a branch for CM-T54 development. The CM-T54 patches are generated vs. v2014.10 tag (c43fd23cf619856b0763a64a6a3bcf3663058c49 commit) in the U-Boot tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
<pre>
git checkout -b cm-t54-dev v2014.10
</pre>
* Apply the CM-T54 patch
<pre>
cd /home/development/cm-t54/u-boot/u-boot-cm-t54
git apply /path/to/cm-t54-u-boot/u-boot/u-boot-v2014.10-cm-t54-2.patch
</pre>

=== Building the firmware images ===
In this section we assume that any version of Sourcery CodeBench Lite toolchain is installed on a host machine and it's location is added to the PATH.
<pre>
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-eabi-
make mrproper
make cm_t54_defconfig && make
</pre>

In the example above, CM-T54 firmware images for SPL ({{filename|MLO}}) and U-Boot ({{filename|u-boot.img}}) will be created in {{filename|/home/development/cm-t54/u-boot/u-boot-cm-t54}}.

== See also ==

* [[U-Boot quick reference]]
* [[U-Boot images]]
* [http://www.denx.de/wiki/U-Boot/Documentation U-Boot documentation]

[[Category:U-Boot]]
[[Category:CM-T54]]

CM-T54: U-Boot: Building Images - Revision history

Grinberg: /* Building the firmware images */