Blame - meta/poky/documentation/sdk-manual/sdk-intro.xml - T103

* Extensible SDK contains the toolchain and debugger if <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_EXT_TYPE'><filename>SDK_EXT_TYPE</filename></ulink> is "full" or <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INCLUDE_TOOLCHAIN'><filename>SDK_INCLUDE_TOOLCHAIN</filename></ulink> is "1", which is the default.

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** Sysroot is managed through the use of <filename>devtool</filename>. Thus, it is less likely that you will corrupt your SDK sysroot when you try to add additional libraries.

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*** You can add runtime package management to the standard SDK but it is not supported by default.

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**** You must build and make the shared state available to extensible SDK users for "packages" you want to enable users to install.

</literallayout>

</para>

<title>The Cross-Development Toolchain</title>

<para>

The

<ulink url='&YOCTO_DOCS_REF_URL;#cross-development-toolchain'>Cross-Development Toolchain</ulink>

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consists of a cross-compiler, cross-linker, and cross-debugger

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that are used to develop user-space applications for targeted

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hardware.

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Additionally, for an extensible SDK, the toolchain also has

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built-in <filename>devtool</filename> functionality.

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This toolchain is created by running a SDK installer script

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or through a

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<ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>

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that is based on your metadata configuration or extension for

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your targeted device.

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The cross-toolchain works with a matching target sysroot.

</para>

</section>

<title>Sysroots</title>

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<para>

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The native and target sysroots contain needed headers and libraries

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for generating binaries that run on the target architecture.

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The target sysroot is based on the target root filesystem image

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that is built by the OpenEmbedded build system and uses the same

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metadata configuration used to build the cross-toolchain.

</para>

</section>

<title>The QEMU Emulator</title>

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<para>

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The QEMU emulator allows you to simulate your hardware while

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running your application or image.

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QEMU is not part of the SDK but is made available a number of

different ways:

If you have cloned the <filename>poky</filename> Git

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repository to create a

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<ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>

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and you have sourced the environment setup script, QEMU is

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installed and automatically available.

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</para></listitem>

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If you have downloaded a Yocto Project release and unpacked

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it to create a Source Directory and you have sourced the

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environment setup script, QEMU is installed and

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automatically available.

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</para></listitem>

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If you have installed the cross-toolchain tarball and you

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have sourced the toolchain's setup environment script, QEMU

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is also installed and automatically available.

</para></listitem>

</itemizedlist>

</para>

</section>

<title><trademark class='trade'>Eclipse</trademark> Yocto Plug-in</title>

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<para>

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The Eclipse IDE is a popular development environment and it fully

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supports development using the Yocto Project.

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When you install and configure the Eclipse Yocto Project Plug-in

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into the Eclipse IDE, you maximize your Yocto Project experience.

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Installing and configuring the Plug-in results in an environment

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that has extensions specifically designed to let you more easily

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develop software.

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These extensions allow for cross-compilation, deployment, and

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execution of your output into a QEMU emulation session.

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You can also perform cross-debugging and profiling.

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The environment also supports many performance-related

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<ulink url='http://www.eclipse.org/linuxtools/index.php'>tools</ulink>

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that enhance your development experience.

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<note>

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Previous releases of the Eclipse Yocto Plug-in supported

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"user-space tools" (i.e. LatencyTOP, PowerTOP, Perf, SystemTap,

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and Lttng-ust) that also added to the development experience.

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These tools have been deprecated with the release of the

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Eclipse Yocto Plug-in.

</note>

</para>

<para>

For information about the application development workflow that

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uses the Eclipse IDE and for a detailed example of how to install

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and configure the Eclipse Yocto Project Plug-in, see the

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"<link linkend='sdk-eclipse-project'>Developing Applications Using <trademark class='trade'>Eclipse</trademark></link>"

Chapter.

</para>

</section>

<title>Performance Enhancing Tools</title>

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<para>

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Supported performance enhancing tools are available that let you

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profile, debug, and perform tracing on your projects developed

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using Eclipse.

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For information on these tools see

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<ulink url='http://www.eclipse.org/linuxtools/'>http://www.eclipse.org/linuxtools/</ulink>.

</para>

</section>

</section>

<title>SDK Development Model</title>

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<para>

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Fundamentally, the SDK fits into the development process as follows:

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The SDK is installed on any machine and can be used to develop

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applications, images, and kernels.

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An SDK can even be used by a QA Engineer or Release Engineer.

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The fundamental concept is that the machine that has the SDK installed

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does not have to be associated with the machine that has the

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Yocto Project installed.

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A developer can independently compile and test an object on their

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machine and then, when the object is ready for integration into an

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image, they can simply make it available to the machine that has the

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Yocto Project.

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Once the object is available, the image can be rebuilt using the

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Yocto Project to produce the modified image.

</para>

<para>

You just need to follow these general steps:

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<emphasis>Install the SDK for your target hardware:</emphasis>

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For information on how to install the SDK, see the

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"<link linkend='sdk-installing-the-sdk'>Installing the SDK</link>"

section.

</para></listitem>

<emphasis>Download or Build the Target Image:</emphasis>

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The Yocto Project supports several target architectures

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and has many pre-built kernel images and root filesystem

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images.</para>

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<para>If you are going to develop your application on

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hardware, go to the

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<ulink url='&YOCTO_MACHINES_DL_URL;'><filename>machines</filename></ulink>

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download area and choose a target machine area

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from which to download the kernel image and root filesystem.

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This download area could have several files in it that

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support development using actual hardware.

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For example, the area might contain

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<filename>.hddimg</filename> files that combine the

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kernel image with the filesystem, boot loaders, and

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so forth.

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Be sure to get the files you need for your particular

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development process.</para>

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<para>If you are going to develop your application and

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then run and test it using the QEMU emulator, go to the

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<ulink url='&YOCTO_QEMU_DL_URL;'><filename>machines/qemu</filename></ulink>

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download area.

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From this area, go down into the directory for your

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target architecture (e.g. <filename>qemux86_64</filename>

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for an <trademark class='registered'>Intel</trademark>-based

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64-bit architecture).

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Download the kernel, root filesystem, and any other files you

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need for your process.

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<note>

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To use the root filesystem in QEMU, you need to extract it.

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See the

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"<link linkend='sdk-extracting-the-root-filesystem'>Extracting the Root Filesystem</link>"

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section for information on how to extract the root

filesystem.

</note>

</para></listitem>

<emphasis>Develop and Test your Application:</emphasis>

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At this point, you have the tools to develop your application.

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If you need to separately install and use the QEMU emulator,

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you can go to

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to download and learn about the emulator.

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See the

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"<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-qemu'>Using the Quick EMUlator (QEMU)</ulink>"

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chapter in the Yocto Project Development Tasks Manual

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for information on using QEMU within the Yocto

Project.

</para></listitem>

</orderedlist>

</para>

<para>

The remainder of this manual describes how to use the extensible

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and standard SDKs.

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Information also exists in appendix form that describes how you can

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build, install, and modify an SDK.

</para>

</section>

</chapter>

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