A20-OLinuXino-LIME and A20-OLinuXino-MICRO

Intro
=====

These are open hardware boards, both based an the AllWinners A20 SoC.

for more details about the boards see the following pages:
 - https://www.olimex.com/Products/OLinuXino/open-source-hardware
 - https://www.olimex.com/Products/OLinuXino/A20/A20-OLinuXino-MICRO/
 - https://www.olimex.com/Products/OLinuXino/A20/A20-OLinuXino-LIME/

The following defconfigs are available:
 - olimex_a20_olinuxino_micro_defconfig
   for the A20-OLinuXino-MICRO board using mainline kernel
 - olimex_a20_olinuxino_lime_defconfig
   for the A20-OLinuXino-LIME board using mainline kernel
 - olimex_a20_olinuxino_lime_mali_defconfig
   for the A20-OLinuXino-LIME board using legacy linux-sunxi kernel
 - olimex_a20_olinuxino_lime2_defconfig
   for the A20-OLinuXino-LIME2 board using mainline kernel

The legacy linux-sunxi kernels are based on the vendor code drops.
They are only useful when accelerated 3D graphics and multimedia support
is strictly necessary.

The Mainline Kernel is already a much better choice for a headless server.
And also the mainline kernel works fine even for a basic Linux desktop
system running on top of a simple framebuffer, which may be good enough for
the users who do not need fancy 3D graphics or video playback acceleration.

(see http://linux-sunxi.org/Linux_Kernel for more details)

How to build it
===============

Configure Buildroot:

    $ make <board>_defconfig

Compile everything and build the rootfs image:

    $ make

Result of the build
-------------------

After building, you should get a tree like this:

    output/images/
    +-- rootfs.ext2
    +-- rootfs.ext4 -> rootfs.ext2
    +-- script.bin (lime_mali)
    +-- sun7i-a20-olinuxino-lime.dtb (lime, mainline)
    +-- sun7i-a20-olinuxino-lime2.dtb (lime2, mainline)
    +-- sun7i-a20-olinuxino-micro.dtb (micro, mainline)
    +-- u-boot.bin
    +-- u-boot-sunxi-with-spl.bin
    `-- zImage


How to write the SD card
========================


Prepare the SD card
-------------------

Erase existing stuff, and create an unique Linux partition with `fdisk`.

    # fdisk /dev/sdX
    Command (m for help): o
    Building a new DOS disklabel with disk identifier 0xf9e1616a.
    Changes will remain in memory only, until you decide to write them.
    After that, of course, the previous content won't be recoverable.

    Command (m for help): n
    Partition type:
        p   primary (0 primary, 0 extended, 4 free)
        e   extended
    Select (default p): p
    Partition number (1-4, default 1): 1
    First sector (2048-7626751, default 2048): 2048
    Last sector, +sectors or +size{K,M,G} (2048-7626751, default 7626751): 
    Using default value 7626751

    Command (m for help): p

    Disk /dev/sdX: 3904 MB, 3904897024 bytes
    4 heads, 16 sectors/track, 119168 cylinders, total 7626752 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: 0xf9e1616a

            Device Boot      Start         End      Blocks   Id  System
    /dev/sdX1                 2048     7626751     3812352   83  Linux

    Command (m for help): w
    The partition table has been altered!

    Calling ioctl() to re-read partition table.
    Syncing disks.

Copy images on the SD card
--------------------------

    # dd if=output/images/rootfs.ext2 of=/dev/sdX1
    # dd if=output/images/u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8


Finish
======

Eject the SD card, insert it in the A20-OLinuXino board, and power it up.