Building the Ultimate Debian SD card for Linux with Kernel 3.4 for A20-OLinuxino-MICRO

 

EDIT: there is newer image with hardware accelerated video: https://olimex.wordpress.com/2014/03/07/building-a20-olinuxino-micro-debian-image-with-hardware-accelerated-video/

 

This is step by step instruction how to Build Debian for A20-OLinuXino with Kernel 3.4

We call this image ULTIMATE as it supports all hardware features and fix all known bugs to the moment 🙂

The built image ready to write on SD card will be linked on our wiki in a hour, these steps below are just for Linux geeks who want to know how things happend and want to do Debian distribution by themself or to modify it.

1. Setup of the toolchain

You should make sure you have the tools for building the Linux Kernel and install them if you don’t have them. To install new software you should be with super user rights on your Linux machine, so do this type in a terminal.

$ sudo su

you will be asked for your password and then your prompt will change to # which means you are now the super user, all future commands should be run in this mode.

First update apt-get links by typing

# apt-get update

Install the toolchain by typing the following.

# apt-get install gcc-4.7-arm-linux-gnueabihf ncurses-dev uboot-mkimage build-essential git

This will install: GCC compiler used to compile the kernal, The kernel config menu
uboot make image which is required to allow the SD card to book into the linux image, Git which allows you to download from the github which holds source code for some of the system, Some other tools for building the kernel

Note that if you use debian may be you will need to add

deb http://www.emdebian.org/debian squeeze main

in the file below:

/etc/apt/sources.list

after the installation you now have all tools to make your very own A20 kernel image!

2. Building Uboot

The Allwinner Linux-Sunxi community uboot is maintained by Henrik Nordstrom aka hno on Freenode irc. You can find him in #linux-sunxi or #olimex channels, if something with uboot is broken he is your man 🙂

First let’s make the directory where we will build the A20-OLinuXino-Micro linux:

# mkdir a20_kernel_3.4/
# cd a20_kernel_3.4/

Then let’s download the uboot sources from GitHub repository, note there are lot of branches but you have to use sunxi branch.
Note that the OLinuXino-A20-Micro board u-boot is tested with the next branch:

# git rev-parse --verify HEAD
8a4621c488f33089d831168bfa5bae210a5684c8

Download u-boot sourses:

# git clone -b sunxi https://github.com/linux-sunxi/u-boot-sunxi.git

After the download you should have a new directory

# cd u-boot-sunxi/

With the following command you can start the uboot build:

# make a20-olinuxino_micro CROSS_COMPILE=arm-linux-gnueabihf-

At the end of the process you can check if everything is OK by

# ls u-boot.bin u-boot-sunxi-with-spl.bin spl/sunxi-spl.bin
spl/sunxi-spl.bin u-boot.bin u-boot-sunxi-with-spl.bin

If you got these files everything is complete, well done so far

# cd ..

You should be in the following directory

/home/user/a20_kernel_3.4/#

3. Building kernel sources for Olinuxino-A20-Micro

The Allwinner Linux-Sunxi community Kernel developers can be reached on http://linux-sunxi.org/Mailing_list

Kernel sources for A20 are available on GitHub. Note that the following building is made with the revision below:

# git rev-parse --verify HEAD
a7350cb6a9ec1aae510e26cdc730f05f12e13f9f

You can download the kernel sources using the following command:

# git clone https://github.com/linux-sunxi/linux-sunxi

After the download go to the kernel directory

# cd linux-sunxi/

Here you need from a20 configuration file – a20_defconfig. The file contains all kernel module settings.

Download a20_defconfig then copy a20_defconfig file to configs directory:

# cp a20_defconfig linux-sunxi/arch/arm/configs/.

and make:

# make ARCH=arm a20_defconfig

The result should be:

configuration written to .config

If you wish to make your changes in the kernel configuration do:

# make ARCH=arm menuconfig

The menuconfig changes a .config text file, which you can view/edit even with a text editor like vi,nano.

With this command you can add or remove different modules for the different peripherials in the kernel. Be careful when use this as this may cause the kernel to not work properly.

Note that before compiling kernel you have to do a patch realted with I2C speed. The patch changes i2c speed from 200kHz to 100kHz.

If you want to use some of olimex’s i2c modules on UEXT then you need from this patch.

download the patch sunxi-i2c.patch and apply the patch:

# patch -p0 < sunxi-i2c.patch

Now you can continue with kernel image compiling

# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 uImage

when this finish’s you will have uImage ready and the result should be:

Image Name: Linux-3.4.67+
Created: Mon Sep 16 13:39:04 2013
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 5450904 Bytes = 5323.15 kB = 5.20 MB
Load Address: 40008000
Entry Point: 40008000
Image arch/arm/boot/uImage is ready

Now you can build the kernel modules:

# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 INSTALL_MOD_PATH=out modules
# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 INSTALL_MOD_PATH=out modules_install

DONE! At this point you have uboot and kernel modules.

The uImage file is located in linux-sunxi/arch/arm/boot/

The kernel modules are located in

linux-sunxi/out/lib/modules/3.x.xx

where 3.x.xx is kernel version

in our case the directory with modules is:

linux-sunxi/out/lib/modules/3.4.67+

4. Format and setup the SD-card

We suggest 4GB class 10 micro sd-card but you can use any card between 2GB and 16GB.

First we have to make the correct card partitions, this is done with fdisk.

Plug SD card into your SD card reader and enter in the terminal

# ls /dev/sd

Then press two times <TAB> you will see a list of your sd devices like sda sdb sdc note that some of these devices may be your hard disk so make sure you know which one is your sd card before you proceed as you can damage your HDD if you choose the wrong sd-device. You can do this by unplugging your sd card reader and identify which “sd” devices remove from the list.

Once you know which device is your sdcard like sda use this text instead of the sdX name in the references below:

# fdisk /dev/sdX

then do these steps:

1. p

will list your partitions

if there are already partitions on your card do:

2. d enter 1

if you have more than one partitition press d while delete them all

3. create the first partition, starting from 2048

n enter p enter 1 enter enter +16M

4. create second partition

n enter p enter 2 enter enter enter

then list the created partitions:

p enter

if you did everything correctly on 4GB card you should see something like:

Disk /dev/sdg: 3980 MB, 3980394496 bytes
123 heads, 62 sectors/track, 1019 cylinders, total 7774208 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System

/dev/sdg1 2048 34815 16384 83 Linux
/dev/sdg2 34816 7774207 3869696 83 Linux

7. w

write changes to sd card
now we have to format the file system on the card:

the first partition should be vfat as this is FS which the Allwinner bootloader understands

# mkfs.vfat /dev/sdX1

the second should be normal Linux EXT3 FS

# mkfs.ext3 /dev/sdX2

5. Write the Uboot and sunxi-spl.bin

You should be in /home/user/a20_kernel_3.4/# directory
Note that you have to write u-boot-sunxi-with-spl.bin in /dev/sdX (not sdX1 or sdX2)

# dd if=u-boot-sunxi/u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8

6. Write kernel uImage you build to the SD-card

You should be in the directory below

/home/user/a20_kernel_3.4/# directory 
# mount /dev/sdX1 /mnt/sd

copy the Kernel uImage to root directory in partition 1

# cp linux-sunxi/arch/arm/boot/uImage /mnt/sd

7. Write script.bin file

script.bin is a file with very important configuration parameters like port GPIO assignments, DDR memory parameters, Video resolution etc,

download the script.bin file

# cp script.bin /mnt/sd
# sync
# umount /dev/sdX1

8. Debian rootfs

The Linux Kernel and Uboot are ready, now we have need from Linux distribution rootfs.

Basically the only difference between the different Linux distributions is the rootfs, so if you put Debian rootfs you will have Debian, if you put Ubuntu rootfs it will be Ubuntu etc.

How to build one is a long topic, the good thing is that there are many already pre-built so we can just download one and use.

exit the kernel directory

# cd ..

You should be in the directory below

# /home/user/a20_kernel_3.4/

download debian rootfs – debian_34_67_fs.tgz

mount your sd card EXT3 FS partition:

# mkdir /mnt/sd
# mount /dev/sdX2 /mnt/sd

and unarchive the rootfs

# tar xzvf debian_34_67_fs.tgz -C /mnt/sd
# ls /mnt/sd

the right result should be:

bin dev home lost+found mnt proc run selinux sys usr
boot etc lib media opt root sbin srv tmp var

Now you have to replace the new generated kernel modules from

/home/user/a20_kernel_3.4/linux-sunxi/out/lib/modules/ to the new debian file system

# rm -rf /mnt/sd/lib/modules/*
# cp -rfv linux-sunxi/out/lib/modules/3.x.xx+/ /mnt/sd/lib/modules/

where x.xx is the kernel version

in our case:

# cp -rfv linux-sunxi/out/lib/modules/3.4.67+/ /mnt/sd/lib/modules/

replace /lib/firmware folder with the generated /linux-sunxi/out/firmware

#rm -rf /mnt/sd/lib/firmware/
#cp -rfv linux-sunxi/out/lib/firmware/ /mnt/sd/lib/
# sync
# umount /mnt/sdX2

at this point you have Debian on your SD card second partition and
you have an SD card ready to boot debian on A20-OLinuXino-Micro

Connect USB-SERIAL-CABLE-F to UEXT Tx.Rx and GND, or connect a HDMI screen. Put the SD-card in A20-OLinuXino-Micro and apply 6-16V power, you should see Uboot and then Kernel messages on the console

default username/password is : root / olimex