It’s not an embedded Linux distribution –
It creates a custom one for you.
The Yocto Project and its Application Development Toolkit (ADT) - “The Answer to Effective Embedded
Application Development”
David Stewart
Intel Corporation
April 11, 2011
Agenda
Challenges Developing Today’s Embedded Software
●
The Yocto Project Build System
●
The Yocto Project Application Development Toolkit (ADT)
●
The ADT Usage Model
●
Example App Development using ADT
●
Benefits of Using the Yocto Project and its ADT
●
Q&A
●
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Challenges Developing Today's Embedded Software
– The Context
SoCs have brought fantastic capabilities to embedded products
●
But... it means that rapidly developed application software is a
key part of the solution
●
Application developer is quite often a different role/skillset than
the system developer
●
Embedded products typically require a targeted application
development effort - focused on rapid development for embedded
devices
●
Customized toolchain and development platform are
essential for embedded software development
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Challenges Developing Today's Embedded Software
Challenges:
Support the app developer role with their own environment
●
Quickly roll out new applications that utilize features in the silicon and
meet time to market (TTM) demands is paramount
●
Time and complexity to build up such a TTM accelerator
●
4/
The Yocto Project Build System
Yocto
Workflow
5/
Setting up the App Developer Environment
System
dev
App
dev
Sysroot:
(Bootable
Linux
filesystem
with dev
headers)
Package
Repository
(networked or
local)
Cross-toolchain
Installation
(eg: /opt/poky)
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Sys Dev builds what the App Dev needs
1.Build the cross toolchain for a specific host system (e.g. x86_64) and
target architecture (e.g arm):
1.Set SDKMACHINE=x86_64 in conf/local.conf
2.Run “MACHINE=qemuarm bitbake meta-toolchain package-index”
2.Build the matching target rootfs (e.g. poky-image-sato-sdk) that
sysroot is based on:
Run “MACHINE=qemuarm bitbake poky-image-sato-sdk packageindex”
(Sato is a gnome mobile environment and visual style that is designed
specifically to work well with small high resolution screens and stylus input)
●
For more simplicity, build them in a single step:
Run “MACHINE=qemuarm bitbake poky-image-sato-sdk metatoolchain package-index”
●
With Yocto, one configuration, one command can generate both
a toolchain and matching rootfs image
7/
ADT Notes
Cross toolchain and image files generated by the Yocto build system
based on the target device metadata configuration
●
Setup target system development environment on the App Dev machine
based on sysroot concept
●
GNU cross-development toolchain of build, packaging, and debug
●Development headers and libraries
●Sysroot represents target device root filesystem
●
Optimized for autotools-type projects
●
For autotool enabled packages just pass host options to configure, e.g.
●
configure --host=arm-poky-linux-gnueabi --with-libtoolsysroot=/home/davest/arm
●
For other projects, ensure that the cross tools are used, e.g.
●
CC=arm-poky-linux-gnueabi-gcc and LD=arm-poky-linux-gnueabi-ld in
makefile
8/
ADT Notes (cont.)
Either Qemu with GL pass-through or real hardware as development
targets
●
User mode NFS support
●
Allow emulator and host access the file system at same time
●
Use package management infrastructure to update packages on
running systems and sysroot: RPM, Deb, OPKG
●
ADT installer script provides customization to set up cross
development environment
●
9/
IDE Support: Eclipse
Eclipse plug-in and user space tool suite offerings further improve
developer productivity
●
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The Yocto Project and ADT Usage Model
11/
Example Application Development Using ADT
A case study to show how to customize a cross development
environment via the Yocto ADT
●
Original cross development setup
●
A x86_64-arm cross toolchain installed under /opt/poky/1.0
●Sysroot extracted from poky-image-sato-sdk rootfs under /home/davest/arm
●
Add support for clutter-based applications on the new device:
●
Step 1. target metadata needs to be extended to add clutter library support,
e.g. clutter-1.4_1.4.2.bb and clutter.inc
●Step 2. Run “bitbake clutter-1.4” to build clutter library packages, using opkg
●
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Example Application Development Using ADT (cont.)
Step 3. Use a package manager (e.g. opkg) to add clutter packages to
sysroot:
●
–opkg-cl
f ~davest/opkg/opkg.conf
–opkg-cl f ~davest/opkg/opkg.conf
install libclutter-glx-1.4-0
–opkg-cl f ~davest/opkg/opkg.conf
install libclutter-glx-1.4-dbg
–opkg-cl f ~davest/opkg/opkg.conf
install libclutter-glx-1.4-dev
-o ~davest/arm update
-o ~davest/arm --force-overwrite
-o ~davest/arm --force-overwrite
-o ~davest/arm --force-overwrite
Step 4. Build clutter autotool based application with
●
–configure
–with-libtool-sysroot=/home/davest/arm --host=arm-pokylinux-gnueabi
–make will use cross tools e.g.
arm-poky-linux-gnueabi-gcc --sysroot=/home/davest/arm
Step 5. Boot up qemu in the unfs mode to test, debug new clutter app on
target emulator
●
–poky-qemu
/home/davest/qemu-kernel/zImage-qemuarm.bin /home/davest/arm
–The shared and updated sysroot as rootfs allows immediate cross debug and run in the target
emulator with no need to recreate a target image
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Example Application Development Using ADT (cont.)
To finish up the device project:
●Create a recipe for your app and include it in the system build
●
User specified sysroot supports multiple build profiles cross
development environment setup for same target architecture
●e.g. Yocto provides,
–minimal, minimal-dev,
–lsb, lsb-dev, lsb-sdk,
–sato, sato-dev, sato-sdk
●
Application development can progress in parallel with system
development
●
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Benefits of Using the Yocto Project and its ADT
Easily build an embedded product focused cross-toolchain
●
Using sysroot, quickly setup a customized cross-development
environment
●
Same build configuration to build the target-specific distribution image
and the cross-toolchain
●
Enhanced developer productivity through ADT Eclipse plug-in, Qemu
emulator and user-space tool suite offerings
●
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Benefits of Using the Yocto Project and its ADT
(cont.)
An embedded board vendor can provide a product-focused
toolchain, tools and development platform in the bundle with
Board Support Package (BSP)s.
●
Enable immediate software development against the new
product that best showcases its unique features
●
Do software and hardware development in parallel, which leads
to great TTM for both software and hardware readiness at
product launch
●
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Questions?
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Backup
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The Yocto Project Tools
The ADT Application user space tools suite contains the following
essential tools that provide target analytical capabilities:
●
PowerTop
●LatencyTop
●Oprofile
●Perf
●Lttng-ust
●SystemTap
●
Yocto 1.0 will also provide the following tools:
●
SystemProf
●Trace-cmd/kernelshark
●blktrace
●
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The Yocto Project ADT Standalone
No IDE required - command line arguments
●
Script files provided:
●
Environment setup script for cross development environment
●Running Poky Qemu images
●
Use package tools, user mode NFS to provision applications to target
devices
●
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The Yocto Project ADT Eclipse Plug-in
Built on top via extensions of the available feature rich Eclipse plug-ins
●
CDT, Linux Tools Project, TCF/RSE
●
Integrates Yocto ADT cross toolchain into CDT
●
Via CDT to interact with tools to achieve cross platform “build, deploy,
test, debug”
●
Intended to be used for GNU autotools projects
●
Leverage TCF and its remote agent mechanism to achieve remote tools
interaction without leaving IDE
●
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Code extract of clutter-1.4_1.4.2.bb and clutter.inc
Clutter-1.4_1.4.2.bb
●
●
require clutter.inc
●
PR = "r0"
●
PACKAGES =+ "${PN}-examples"
●
FILES_${PN}-examples = "${bindir}/test-* ${pkgdatadir}/redhand.png"
●
SRC_URI = "http://source.clutter-project.org/sources/clutter/1.4/clutter-${PV}.tar.bz2 \
●
...
Clutter.inc
●
●
DESCRIPTION = "Clutter graphics library"
●
HOMEPAGE = "http://www.clutter-project.org/"
●
LICENSE = "LGPL"
●
COMPATIBLE_MACHINE = "(zylonite|mx31litekit|omap-3430ldp|omap-3430sdp|mx31ads|qemuarm|qemux86|ipodtouch|atom-pc|menlow)"
●
STDDEPENDS = "virtual/libx11 gtk-doc-native pango glib-2.0 libxfixes gtk+ libxi"
●
BASE_CONF = "--disable-gtk-doc ${@get_clutter_fpu_setting(bb, d)}"
●
DEPENDS = "${STDDEPENDS} virtual/libgl gettext"
●
EXTRA_OECONF = "${BASE_CONF} --with-flavour=glx"
●
DEPENDS_zylonite = "${STDDEPENDS} libgles-zylonite tslib"
●
EXTRA_OECONF_zylonite = "${BASE_CONF} --with-flavour=eglnative"
●
PACKAGE_ARCH_zylonite = "${MACHINE_ARCH}"
●
LDFLAGS_append_zylonite = " -lnws -lstdc++ "
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Resources
●
http://www.yoctoproject.org
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