i.MX53 SODIMM PC Barebox

i.MX53 SODIMM PC - Development Kit uses Barebox as a bootloader. This page displays how to configure and build it.

Barebox is a bootloader responsible for hardware initialization, loading and booting Linux kernel. It is also used for module flashing.

Building images

Set toolchain

Export toolchain variables for every related terminal session.

Set shell variables

BB_VERSION=2014.03.0
SW_VERSION=20150308

Download and extract source code

mkdir -pv ~/workdir/vmx53/barebox/
cd ~/workdir/vmx53/barebox/
wget http://barebox.org/download/barebox-${BB_VERSION}.tar.bz2
tar xvjf barebox-${BB_VERSION}.tar.bz2
mv barebox-${BB_VERSION} barebox-${BB_VERSION}.orig
cp -rv barebox-${BB_VERSION}.orig barebox-${BB_VERSION}.work

Download and apply Voipac patches

cd ~/workdir/vmx53/barebox/
wget http://downloads.voipac.com/files/i.MX53_SODIMM_PC-Development_Kit/module/software/barebox/sources/barebox-2014.03.0_vmx53_20151129.cfg
wget http://downloads.voipac.com/files/i.MX53_SODIMM_PC-Development_Kit/module/software/barebox/sources/barebox-2014.03.0_vmx53_20151129.patch
cd ~/workdir/vmx53/barebox/barebox-${BB_VERSION}.work
patch -p1 < ../barebox-${BB_VERSION}_vmx53_${SW_VERSION}.patch
cp ../barebox-${BB_VERSION}_vmx53_${SW_VERSION}.cfg .config

Compile

Output file is stored in arch/arm/pbl/zbarebox.bin:

cd ~/workdir/vmx53/barebox/barebox-${BB_VERSION}.work
#make ARCH=arm menuconfig
make -j4

Configuring bootloader environment

Edit boot options

Barebox provides 4 boot configurations by default:

• nand-legacy-ubi
  • Load kernel (nand - kernel)
  • Attach rootfs (nand - rootfs)
• nand-dtb-ubi
  • Load kernel (nand - kernel)
  • Load device tree (nand - bareboxenv)
  • Attach rootfs (nand - rootfs)
• net-legacy
  • Load kernel (tftp)
  • Attach rootfs (nfs)
• net-dtb
  • Load kernel (tftp)
  • Load device tree (tftp)
  • Attach rootfs (nfs)

Boot configuration files support custom kernel definition. These settings also allow updating paths or names for binaries:

barebox@Voipac VMX53:/ edit /env/boot/net-dtb

barebox@Voipac VMX53:/ edit /env/config

# list of boot entries. These are executed in order until one
# succeeds. An entry can be:
# - a filename in /env/boot/
# - a full path to a directory. All files in this directory are
#   treated as boot files and executed in alphabetical order
global.boot.default=nand-dtb-ubi

DTB file selection

As different module configurations use altered device trees, defining the correct board variant is important:

barebox@Voipac VMX53:/ edit /env/config
...
# BASIC=557, PRO=668, MAX=779
#global.vmxmodel=557
global.vmxmodel=668
#global.vmxmodel=779
...
barebox@Voipac VMX53:/ saveenv
barebox@Voipac VMX53:/ reset