Bake 64-bit raspberryPI3 images with Yocto/OpenEmbedded

Bake 64-bit raspberryPI3 images with Yocto/OpenEmbedded

Overview

RaspberryPI3 SBC and CM come with cortex-a53 based SOC which is 64-bit capable and uses ARM-v8 architecture. Originally RaspberryPI 3 was released with 32bit support alone which is backward compatible with RaspberryPI 2. However, over period of last couple of years a lot of development has gone into enabling 64-bit on ARM in community,  Eric Anholt’s VC4 drivers have matured on 64bit kernels, various userspace packages have been ported by Linaro and other communities.  We have put efforts in integrating all these efforts for full system using OpenEmbedded/Yocto framework. The support is fairly new and therefore there might be some issues still lurking, Here we will go through the steps for building full Graphical images.

Build Setup

Since the support is new, its recommended to use master (upcoming Rocko 2.5 release) and newer

mkdir rpi-yocto; cd rpi-yocto
git clone git://git.yoctoproject.org/poky
git clone git://git.openembedded.org/meta-openembedded
git clone git://git.yoctoproject.org/meta-raspberrypi
git clone git://github.com/96boards/meta-96boards

source poky/oe-init-build-env rpi64-build

bitbake-layers add-layer ../meta-raspberrypi
bitbake-layers add-layer ../meta-96boards
bitbake-layers add-layer ../meta-openembedded/meta-oe
bitbake-layers add-layer ../meta-openembedded/meta-xfce
bitbake-layers add-layer ../meta-openembedded/meta-python
bitbake-layers add-layer ../meta-openembedded/meta-perl
bitbake-layers add-layer ../meta-openembedded/meta-gnome
bitbake-layers add-layer ../meta-openembedded/meta-networking

Edit conf/local.conf  to set machine

MACHINE = "raspberrypi3-64"

Build Sato Image ( Yocto Project Reference GUI image )

bitbake core-image-sato

Build XFCE image

If you intend to build a full desktop system like XFCE then build core-image-minimal-xfce

bitbake core-image-minimal-xfce

Prepare SD-Card

sudo dd if=tmp/deploy/images/raspberrypi3-64/core-image-sato-raspberrypi3.rpi-sdimg of=/dev/sdX

where X is the letter a,b,c which your build machine would have mounted the Micro-SD card on you can check that with

dmesg | tail -10

Resize SD-Card

Add in local.conf

CORE_IMAGE_EXTRA_INSTALL_append = " 96boards-tools "

build the image again and flash it to SD-Card, this will expand the rootfs to span over complete SD card.

Using MUSL C library

Musl is a light weight alternative to glibc which is fully supported in OpenEmbedded-core and Yocto project. In order to use musl instead of glibc add ( in local.conf )

TCLIBC = "musl"

Using Clang Compiler

Clang is supported via a layer of its own, if you intend to use clang to compile the packages, you have to add meta-clang to layer mix.

cd rpi-yocto; git clone git://github.com/kraj/meta-clang

bitbake-layers add-layer ../meta-clang

If clang should be used as default compiler then add following in local.conf

TOOLCHAIN ?= "clang"

Please note that there is a small number of packages which still would use gcc to build. e.g. for core-image-sato we still build following packages with gcc

  • pixman
  • linux-kernel
  • glibc( if you use it)
  • elfutils
  • tcp-wrappers
  • busybox

Status

What works

  • Ethernet
  • Graphics
  • USB
  • Keyboard/mouse
  • HDMI

 

TO-DO

  • Validate bluetooth
  • Validate on board WiFi
  • Video playback
  • Sound

Need Help ?

Please ask questions on IRC or mailing lists

irc.freenode.net#yocto
irc.freenode.net#oe

Mailing lists

yocto@yoctoproject.org
openembedded-devel@lists.openembedded.org

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