Olimex OlinuXino a10 Lime uBoot, Kernel and root image guide

20-12-2014 | Remy van Elst


Table of Contents


olimex

The Olimex OlinuXino A10 LIME is an amazing, powerfull and cheap open source ARM development board. It costs EUR 30, and has 160 GPIO. This guide is a cleaned up version of theirs with instructions to build your own kernel and u-boot image on Ubuntu 14.04

Buy the board here: https://www.olimex.com/Products/OLinuXino/A10/A10-OLinuXino-LIME/open-source-hardware and see my other tutorials and a small image here: https://raymii.org/s/tags/olimex.html

The original guide can be found here: http://olimex.wordpress.com/2013/12/13/building-debian-linux-image-for-a10-olinuxino-lime-with-kernel-3-4-67/

This guide has been adapted to work on Ubuntu 14.04, some package names, instructions and commands were incorrect. Also, all the files are not on Google drive anymore, but on my servers. The original bad english has been cleaned up to be less bad. The guide however is of less quality than you normally get from me.

For Allwinner Kernel related questions please ask on Linux Sunxi Mailing List in Google Groups: https://groups.google.com/forum/#!forum/linux-sunxi

For Uboot related questions please ask on Linux Sunxi Mailing List in Google Groups: https://groups.google.com/forum/#!forum/linux-sunxi


Contents

  • Building u-boot (boat loader)
  • Building the kernel
  • Partitioning the SD card
  • Placing the bootloader, kernel and kernel modules
  • Placing the root filesystem

Install required packages

Install the toolchain and other required development packages:

apt-get update
apt-get install gcc-4.7-arm-linux-gnueabihf ncurses-dev build-essential git u-boot-tools gcc-arm-linux-gnueabihf

If you want to cross compile on Debian instead of Ubuntu, you need the following set of packages:

apt-get install binutils-arm-linux-gnueabihf ncurses-dev build-essential git u-boot-tools gcc-arm-linux-gnueabihf

Create a working directory and go in to it:

mkdir A10_kernel_3.4/
cd A10_kernel_3.4/

Building Uboot

u-boot is the bootloader, it is a GRUB alternative for small/embedded systems.

Download u-boot sources:

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

Note that this guide was written with the revision below:

git rev-parse --verify HEAD
44b53fd3928f15c34993ec8c6b8c2efcb79769ee

Start the uboot build:

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- distclean
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- A10-OLinuXino-Lime_config
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-

At the end of the process you should have at least the following files:

# 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

Go back into the working directory:

cd ..

Building the kernel

Kernel sources for A10 are available on GitHub. Use git to download the kernel sources for the board:

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

Note that this guide was written with the revision below:

git rev-parse --verify HEAD
e37d760b363888f3a65cd6455c99a75cac70a7b8

The following file contains all the kernel config settings. If you've ever built your own kernel you can use make menuconfig etc to change the settings. For now, download it:

wget https://raymii.org/s/inc/downloads/olinux/a10/a10lime_defconfig

Their kernel contains weird choices, for example iptables is not available, but wireless drivers are. You can save space on the kernel by removing things like that. If you want to run it as a server, you need to compile most of the network settings back in. I use the following config, with network stuff included so that I can use lxc containers on the board (veth, bridge and vlan support etc.):

wget https://raymii.org/s/inc/downloads/olinux/a10/kernel_config_raymii

Copy a10lime_defconfig file to config directory:

cp a10lime_defconfig linux-sunxi/arch/arm/configs/
# or my config:
cp kernel_config_raymii linux-sunxi/arch/arm/configs/

Prepare the config file:

make ARCH=arm a10lime_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

You can add or remove different modules for the different peripherials in the kernel with menuconfig. Be careful with this as it may cause the kernel to not work properly.

Compile the kernel:

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

The result after a while should be like this:

Image Name:   Linux-3.4.90+
Created:      Fri Jun 13 16:28:39 2014
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    4447440 Bytes = 4343.20 kB = 4.24 MB
Load Address: 40008000
Entry Point:  40008000
Image arch/arm/boot/uImage is ready

Compile the kernel modules:

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

After the compilations are finished 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/3.4.90+

Format and setup the SD-card

First we have to partition the SD card with fdisk. Plug SD card into your SD card reader. Use a command like dmesg to get the correct device. If you select the wrong device you might overwrite your own hard drive, so make sure you have the correct one.

Start fdisk on the correct device:

fdisk /dev/sdX

List the partitions:

p

If there are already partitions on the card you should delete them. This will erase the data on the SD card:

d 
1

If you have more than one partitition press d again and provide the number, like 2, 3 etc.

Create the first partition, starting from 2048

n
p
1
# enter twice
+16M

Create the second partition

n
p
2 
# enter three times

List the created partitions:

p 

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

Disk /dev/sdX: 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/sdX1            2048       34815       16384   83  Linux
/dev/sdX2           34816     7774207     3869696   83  Linux

Write it to the SD card:

w

Create the file system on the first partition. This should be vfat as this is filesystem which the Allwinner bootloader understands:

mkfs.vfat /dev/sdX1

The second should be a Linux ext4 partition:

mkfs.ext4 /dev/sdX2

Writing the bootloader and related files

You should be in the ~/A10kernel3.4/ folder.

The image u-boot-sunxi-with-spl.bin should be written to the device /dev/sdX (not a partition like sdX1 or sdX2).

Use dd to write the image we built earlier to the sd card:

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

Mount the first partition:

# mkdir /mnt/sd
mount /dev/sdX1 /mnt/sd

Copy the kernel uImage to root directory of partition 1:

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

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

Download the file and place it on the SD card:

wget -O /mnt/sd/script.bin https://raymii.org/s/inc/downloads/olinux/a10/script.bin

boot.scr has the uboot commands to load script.bin, kernel, initrd, set kernel parameters and booting the device.

If you want to change it you can read this guide: https://github.com/linux-sunxi/u-boot-sunxi/wiki

Download boot.scr and place it on the SD card:

wget -O /mnt/sd/boot.scr https://raymii.org/s/inc/downloads/olinux/a10/boot.scr

Unmount the partition:

sync
umount /dev/sdX1

Debian rootfs

You can download my own image from here: https://raymii.org/s/articles/OlimexA10-OLinuXino-LIMEminimaldebian7_image.html. It is smaller than the Olimex image, but has no GUI etc. The standard olimex Debian image is quite large and has weird software choices.

The image provided by Olimex is mirrored here. Download it:

wget https://2162bb74000a471eb2839a7f1648771a.objectstore.eu/olimex/a10_lime_debian_3_4_90_rel_3.tgz

Mount the second partition on the SD card:

mount /dev/sdX2 /mnt/sd

Unpack the rootfs to the SD card:

tar xzvf a10_lime_debian_3_4_90_rel_3.tgz -C /mnt/sd

The unpacked filesystem looks like below:

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

You have to replace the new generated kernel modules from ~/A10_kernel_3.4/linux-sunxi/out/lib/modules/ to the debian file system we've just unpacked:

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/3.4.90+/ /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/

Unmount the SD card:

sync
umount /mnt/sdX2

Connect USB-SERIAL-CABLE-F to UEXT Tx.Rx and GND, or connect a HDMI screen. Put the SD-card in A10-OLinuXino-Lime and apply 5V power, you should see Uboot and then Kernel messages on the console.

The default username/password is : root / olimex


Tags: allwinner, arm, debian, gpio, minimal, olimex, olinuxino, raspberry-pi,