configs: add defconfig for the Atmel SAMA5D3 Xplained board

Atmel SAMA5D3 Xplained board

============================

This document explains how to set up a basic Buildroot system on the

Atmel SAMA5D3 Xplained board, whose main site is

http://www.atmel.com/tools/ATSAMA5D3-XPLD.aspx. Additional details can

also be found on the http://www.at91.com/linux4sam/bin/view/Linux4SAM/

web site.

Note that the default Buildroot configuration is prepared to boot from

an SD card: the first stage bootloader, second stage bootloader,

kernel image and root filesystem are all located on the SD card. Some

adjustements in the bootloader configuration will be needed to boot

from NAND flash.

Configuring and building Buildroot

----------------------------------

  make atmel_xplained_defconfig

  make

Preparing the SD card

---------------------

The SD card must be partitionned with at least two partitions: one

FAT16 partition for the bootloaders, kernel image and Device Tree

blob, and one ext4 partition for the root filesystem. To partition the

SD card:

sudo sfdisk -uM /dev/mmcblk0 <<EOF

,64,6

;

EOF

This creates a 64 MB partition for the FAT16 filesystem (type 6) and

uses the rest for the ext4 filesystem used for the root filesystem.

Then, format both partitions:

sudo mkfs.msdos -n boot /dev/mmcblk0p1

sudo mkfs.ext4 -L rootfs -O ^huge_file /dev/mmcblk0p2

 Note: the -O ^huge_file option is needed to avoid enabling the huge

 files features of ext4 (to support files larges than 2 TB), which

 needs the kernel option CONFIG_LBDAF to be enabled.

Mount both partitions (if not done automatically by your system):

sudo mount /dev/mmcblk0p1 /media/boot

sudo mount /dev/mmcblk0p2 /media/rootfs

Copy the bootloaders, kernel image and Device Tree blob to the first

partition:

cp output/images/sama5d3_xplained-sdcardboot-uboot-3.6.2.bin /media/boot/boot.bin

cp output/images/u-boot.bin /media/boot/u-boot.bin

cp output/images/zImage /media/boot/zImage

cp output/images/at91-sama5d3_xplained.dtb /media/boot/at91-sama5d3_xplained.dtb

Extract the root filesystem to the second partition:

sudo tar -C /media/rootfs -xf output/images/rootfs.tar

Unmount both partitions:

sudo umount /media/boot

sudo umount /media/rootfs

Insert your SD card in your Xplained board, and enjoy. The default

U-Boot environment will properly load the kernel and Device Tree blob

from the first partition of the SD card, so everything works

automatically.

# Architecture

BR2_arm=y

BR2_cortex_a5=y

# Toolchain configuration

BR2_ARM_EABIHF=y

BR2_KERNEL_HEADERS_VERSION=y

BR2_DEFAULT_KERNEL_VERSION="3.15"

BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_15=y

# Kernel configuration

BR2_LINUX_KERNEL=y

BR2_LINUX_KERNEL_CUSTOM_VERSION=y

BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.15"

BR2_LINUX_KERNEL_DEFCONFIG="sama5"

BR2_LINUX_KERNEL_ZIMAGE=y

BR2_LINUX_KERNEL_DTS_SUPPORT=y

BR2_LINUX_KERNEL_INTREE_DTS_NAME="at91-sama5d3_xplained"

# First stage bootloader

BR2_TARGET_AT91BOOTSTRAP3=y

BR2_TARGET_AT91BOOTSTRAP3_DEFCONFIG="sama5d3_xplainedsd_uboot"

# Second stage bootloader

BR2_TARGET_UBOOT=y

BR2_TARGET_UBOOT_BOARDNAME="sama5d3_xplained_mmc"

BR2_TARGET_UBOOT_CUSTOM_VERSION=y

BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2014.04"