It’s not an embedded Linux distribution – It creates a custom one for you.

David Stewart Intel Corporation

April 11, 2011

The Yocto Project and its Application Development Toolkit (ADT) - “The Answer to Effective Embedded Application Development”

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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

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The Yocto Project Build System

Yocto Workflow

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Setting up the App Developer Environment

Cross-toolchain Installation

(eg: /opt/poky)

Sysroot: (Bootable

Linux filesystem with dev headers)

System dev

App dev

Package Repository

(networked or local)

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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 package-

index”

(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 meta-

toolchain package-index”

With Yocto, one configuration, one command can generate both a toolchain and matching rootfs image

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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-libtool-

sysroot=/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

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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

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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

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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 -o ~davest/arm update

–opkg-cl f ~davest/opkg/opkg.conf -o ~davest/arm --force-overwrite

install libclutter-glx-1.4-0

–opkg-cl f ~davest/opkg/opkg.conf -o ~davest/arm --force-overwrite

install libclutter-glx-1.4-dbg

–opkg-cl f ~davest/opkg/opkg.conf -o ~davest/arm --force-overwrite

install libclutter-glx-1.4-dev

●Step 4. Build clutter autotool based application with –configure –with-libtool-sysroot=/home/davest/arm --host=arm-poky-

linux-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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