Going Forward

Introduction

This page collects all material that allows you to build the demo binaries from sources.

It is a summary of building instructions for each component found on http://www.linux4sam.org/twiki/bin/view/Linux4SAM

Building the components from sources

AT91Bootstrap

For this demo revision :

• AT91Bootstarp -> 1.9

Sources

Sources and build process are described in the AT91Bootstrap application note page on http://www.atmel.com .

You can also retrieve them from ftp://www.linux4sam.org/pub/at91bootstrap .

A rewritten version of AT91bootstrap which fixes the page boundary problem and also supports some other options is available as part of the buildroot project at http://buildroot.uclibc.org/

Build process

To compile an AT91Bootstrap project:

1. go into the board directory
2. select your board by going into the corresponding board directory
3. select your media by going into the corresponding directory
4. run make

Example: To compile a DataFlash boot project for AT91SAM9260-EK board, type the following commands:

cd board/at91sam9260ek/dataflash
make clean

make

make CROSS_COMPILE=<path_to_cross-compiler/cross-compiler-prefix->

path_to_cross-compiler is only needed if it is not in your PATH.
Usually cross-compiler-prefix- looks like arm-linux- or arm-elf-

U-Boot

For this demo revision :

• y.y.y -> 1.1.5
• x.x -> 1.7

Sources

To get the u-boot bootloader sources for AT91 product you have to go through the following steps (note that x.x.x and y.y must be replace by the corresponding revision numbers) :

• download the u-boot sources from the link in the first column below and extract it:

wget ftp://ftp.denx.de/pub/u-boot/u-boot-x.x.x.tar.bz2
tar xvjf u-boot-x.x.x.tar.bz2
cd u-boot-x.x.x

• take the corresponding AT91 u-boot patch set (second column):

wget http://www.linux4sam.org/twiki/pub/Linux4SAM/U-Boot/u-boot-x.x.x_atmel_y.y.diff.bz2

• apply it on top of the original u-boot:

bzcat u-boot-x.x.x_atmel_y.y.diff.bz2 | patch -p1

You will have a fresh source copy of the AT91 u-boot.

Build process

Once the AT91 u-boot sources available, cross-compile u-boot is made in two steps : configuration and compiling. Check the Configuration chapter in u-boot reference manual.

Note that both arm-elf- and arm-linux- ARM GCC cross-compiler types are suitable for u-boot building.

Some newer version of make produce errors while compiling this u-boot. We advice you to use an older make executable: check the SoftwareTools page.

Here are the building steps for the AT91sam9263ek board:

make distclean
make at91sam9263ek_config
make CROSS_COMPILE=<path_to_cross-compiler/cross-compiler-prefix->

path_to_cross-compiler is only needed if it is not in your PATH.
Usually cross-compiler-prefix- looks like arm-linux- or arm-elf-

The result of these operations is a fresh u-boot binary called u-boot.bin corresponding to the binary ELF file u-boot.

• u-boot.bin is the file you should store on the board
• u-boot is the ELF format binary file you may use to debug u-boot through a JTag link for instance.

Linux Kernel

For this demo revision :

• xx -> 24
• experimental patch : 2.6.24.at91.2-exp.patch

Sources

To get an experimental Linux4SAM kernel up and running on an AT91 product, you have to go through the following steps:

    1. identify on which linux kernel revision the experimental patches will apply
    2. download the corresponding Linux kernel

wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.xx.tar.bz2
tar xvjf linux-2.6.xx.tar.bz2
cd linux-2.6.xx

wget http://maxim.org.za/AT91RM9200/2.6/2.6.xx-at91.patch.gz
zcat 2.6.xx-at91.patch.gz | patch -p1

wget ftp://www.linux4sam.org/pub/linux/2.6.xx-at91-exp.patch.gz

wget ftp://www.linux4sam.org/pub/linux/2.6.xx.at91.y/2.6.xx.at91.y-exp.patch.gz

zcat linux-2.6.xx-at91-exp.diff.gz | patch -p1

You will now have an updated copy of the experimental Linux4SAM kernel.

Build process

Now you have to configure the Linux kernel according to your hardware. First identify your kernel revision, your board and then, download the corresponding configuration file. Default configuration files are provided here.

wget http://www.linux4sam.org/twiki/pub/Linux4SAM/LinuxKernel/at91sam926yek_defconfig
cd linux-2.6.xx
cp at91sam926yek_defconfig .config
make ARCH=arm oldconfig 

At this step, you can modify default configuration

make ARCH=arm menuconfig 

And build the Linux kernel image

make ARCH=arm  CROSS_COMPILE=<path_to_cross-compiler/cross-compiler-prefix->

OpenEmbedded / Angstrom

A step-by-step comprehensive installation is explained in the OpenEmbedded Getting Started page. The following lines have to be considered as an add-on that is AT91 specific or that can facilitate your setup.

Sources

Once in your OpenEmbeddedDirectory, download a snapshot of the OpenEmbedded monotone database going to http://wiki.openembedded.net/snapshots/.
To choose the proper one:

• just take the OE.mtn.bz2 file and, once the database uncompressed, run a mtn --db=/stuff/OE.mtn db migrate
• or, take the OE-this-is-for-mtn-0.3x.mtn.bz2 that is in keeping with the version of your monotone program (checked with mtn --version).

Before uncompressing the OE database, it is recommended to verify its integrity :

md5sum -c OE.mtn.bz2.md5sum

OpenEmbedded upstream snapshot

We start with an OpenEmbedded snapshot from the official "upstream" OpenEmbedded project. This snapshot contains the BitBake recipes for thousands of packages.

Here is the OpenEmbedded release we build our solution with : aa44d626baaae40ee498aea453176a8aea90d9fc

So you have to checkout this revision of the OE tree :

mtn --db=/stuff/OE.mtn checkout -r aa44d626baaae40ee498aea453176a8aea90d9fc --branch=org.openembedded.dev

AT91 OpenEmbedded / Angstrom overlay tree or patch

In addition to the upstream recipes, we also have a set of our own recipes or modifications of the original ones. So, the following patch applies to the tree that you just checkouted.

note however that the goal of this patch is to merge the most of it bits into the mainstream OE tree.

Then download and install this patch :

cd org.openembedded.dev
zcat ../oe_angstrom_at91.diff.gz | patch -p1
cd ..

Setup local configuration and environment variables

The local configuration file is derived from the example file org.openembedded.dev/conf/local.conf.sample . The local configuration is located in build/conf/local.conf . Here is the local.conf used to build Linux4SAM root file system.

Read comments in it as it will bring you valuable information and allow you to adapt it to your own environment and building host (directory structure for example).

In addition, some environment variables have to be set before running a build process. We setup those variables via a little script env-oe.sh :

#!/bin/sh

OE_DIR=/stuff

export PATH=${OE_DIR}/bitbake/bin:$PATH
export BBPATH=${OE_DIR}/build:${OE_DIR}/org.openembedded.dev

Then, source this script :

source ./env-oe.sh

Start building

Begin with a little set of packages :

bitbake angstrom-minimal-image

even a minimal image will require a big amount of time because of the cross-toolchain building process.

The console and graphical images are built using the following recipes respectively :

bitbake angstrom-console-image-demo
bitbake angstrom-x11-image-demo