[webinar] an introduction to the yocto embedded framework

© Integrated Computer Solutions, Inc. All Rights Reserved

An Introduction to the Yocto Embedded

Framework

Jeff Tranter <[email protected]>Integrated Computer Solutions, Inc.


Agenda

• What is Yocto?• Why is it Needed?• What Yocto Provides• Benefits/Advantages• Limitations/Disadvantages• Yocto Versions• Other Framework Options• Yocto Architecture• Major Components• Using Yocto - Basic Steps• OpenEmbeddedBuild System

• Bitbake Metadata• Example - Emulator• Example - Beaglebone Black• Building an SDK• Packaging• Toaster GUI• Qt Yocto Support• Doing More• Tips For Getting Started• References• Summary• Q&A


What is Yocto?

• Project to provide templates, tools and methods to create custom Linux-based embedded systems• Founded in 2010• Open Source, managed by The Linux Foundation• Vendor and platform neutral• Collaborative effort among participants• Members/participants/sponsors include Intel, AMD, Broadcom, TI,

Freescale, LG Electronics, Huawei, Mentor Graphics, Dell, The Qt Company


Why Is It Needed?

• Embedded development is significantly harder than native/desktop development• Cross-compilation• Wide scope: boot loader, kernel, BSP/device drivers, packaging

format, utilities, applications, SDK• Large, time consuming to build• Desire for repeatability, automation• Licensing issues• Regular need for security and other updates


What Yocto Provides

• Framework for creating embedded Linux systems• Targets supported: ARM, PPC, MIPS, x86, x86-64• Hosted on common Linux x86 desktop platforms (CentOS, Fedora,

openSUSE, Ubuntu)• OpenEmbedded build system with bitbake build engine• IDE• Graphical interface to build system


Benefits/Advantages

• Reduced development effort/time• Improved quality• Automation• Stability• Repeatability


Limitations/Disadvantages

• Embedded Linux targets only• Development tools run on desktop Linux only (or in a Linux vm

hosted on e.g. Windows or MacOS)• Doesn't dictate a specific Linux distribution (but offers Poky as a

reference distribution)• Large, complex, can have steep learning curve


Yocto Versions/Code Names


Other Embedded Frameworks

• Baserock• Buildroot• Crosstool/CrosstoolNG• Embedded Debian/Fedora/Gentoo/SUSE/Ubuntu


Yocto Architecture


Major Components

• bitbake• Poky Linux distribution• Emulator• Toaster GUI• SDK• Eclipse IDE plugin• Build Appliance


Using Yocto - Basic Steps

1. Set up tools on a Linux host machine.2. Configure bitbake for embedded hardware.3. Build software components, bootloader, root fs, image.4. Write boot image and file system.5. Set up SDK.6. Develop and iterate.


bitbake Build System

Steps:• fetch• extract• patch• configure• build• install• package


Bitbake Metadata


Example - Building For Emulator

$ sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat libsdl1.2-dev xterm


Example - Building For Emulator

$ mkdir yocto$ cd yocto$ wget http://downloads.yoctoproject.org/releases/yocto/yocto-2.2/poky-morty-16.0.0.tar.bz2$ tar xjvf poky-morty-16.0.0.tar.bz2$ cd poky-morty-16.0.0

$ source oe-init-build-env$ edit conf/local.conf$ bitbake core-image-sato

$ runqemu qemuarm


Example - Building for Beaglebone Black


Example - Building for Beaglebone BlackDevice Boot Start End Blocks Id System/dev/mmcblk0p1 * 2048 146570 72261+ c W95 FAT32(LBA)/dev/mmcblk0p2 146571 8535178 4194304 83 Linux

$ sudo mkfs.vfat -F 16 -n "boot" /dev/mmcblk0p1$ sudo mke2fs -j -L "root" /dev/mmcblk0p2


Example - Building for Beaglebone Black$ cp tmp/deploy/images/beaglebone/MLO-beaglebone /media/$LOGNAME/boot/MLO

$ cp tmp/deploy/images/beaglebone/u-boot-beaglebone.img /media/$LOGNAME/boot/u-boot.img

$ sudo tar x -C /media/$LOGNAME/root -f tmp/deploy/images/beaglebone/core-image-sato-beaglebone.tar.bz2


Building an SDK

$ bitbake core-image-sato -c populate_sdk

Output is:

tmp/deploy/sdk/poky-glibc-x86_64-core-image-sato-armv5e-toolchain-2.2.sh


Building an SDK

$ ~/yocto/poky-morty-16.0.0/build/tmp/deploy/sdk/poky-glibc-x86_64-core-image-sato-armv5e-toolchain-2.2.sh

Poky (Yocto Project Reference Distro) SDK installer version 2.2===============================================================Enter target directory for SDK (default: /opt/poky/2.2): ~/sdkYou are about to install the SDK to "/home/tranter/sdk". Proceed[Y/n]? YExtracting SDK......................................................................doneSetting it up...doneSDK has been successfully set up and is ready to be used.Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g.$ . /home/tranter/sdk/environment-setup-armv5e-poky-linux-gnueabi


Building an SDK

$ . /home/tranter/sdk/environment-setup-armv5e-poky-linux-gnueabi

$ echo $CXXarm-poky-linux-gnueabi-g++ -march=armv5e -marm --sysroot=/home/tranter/sdk/sysroots/armv5e-poky-linux-gnueabi

$ $CXX helloworld.cpp

$ file a.out

a.out: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 3.2.0


Packaging

• Not required, but often useful even for embedded systems.• Yocto doesn't impose a packaging format.• Common package formats include:• rpm• deb/dpkg• ipkg• opkg


Toaster GUI


Yocto Qt Support

Yocto Qt 5 recipes:• https://github.com/meta-qt5/meta-qt5

Qt for Device Creation (boot2qt):• http://code.qt.io/cgit/yocto/meta-boot2qt.git/• http://code.qt.io/cgit/yocto/meta-qt5.git/


More About Bitbake

• Python based language for configuration files.• Supports variables, include files, functions, inheritance.• Uses scripts called "recipes".• Many command line options.• Configuration files in build/conf• Understands dependencies.• Multithreaded, runs a server process in the background.


Doing More - Writing Recipes

• Needed to build your own components with bitbake• Shell or Python scripts (.bb files)• Standardized format


Doing More - Kernel Recipes

• Recipes to configure, patch, and build the Linux kernel• More complex


Doing More - BSPs

• BSP = Board Support Package.• Adaptations for specific hardware.• Hardware vendor, OS vendor, or third party may provide this.


Doing More - Eclipse Integration


Doing More - Licensing and Compliance


Tips For Getting Started


References

1. Embedded Linux Systems with the Yocto Project, Rudolf Streif2. https://www.yoctoproject.org/3. https://github.com/meta-qt5/meta-qt54. http://code.qt.io/cgit/yocto/meta-boot2qt.git/5. http://code.qt.io/cgit/yocto/meta-qt5.git/6. http://www.ics.com/blog/yocto-quick-start

https://www.yoctoproject.org/

https://github.com/meta-qt5/meta-qt5

http://code.qt.io/cgit/yocto/meta-boot2qt.git/

http://code.qt.io/cgit/yocto/meta-qt5.git/

http://www.ics.com/blog/yocto-quick-start


Summary


Questions?


An Introduction to the Yocto Embedded

Framework

Jeff Tranter <[email protected]>Integrated Computer Solutions, Inc.

[webinar] an introduction to the yocto embedded framework

Software