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diff --git a/yocto-poky/documentation/sdk-manual/sdk-intro.xml b/yocto-poky/documentation/sdk-manual/sdk-intro.xml new file mode 100644 index 000000000..88ae77831 --- /dev/null +++ b/yocto-poky/documentation/sdk-manual/sdk-intro.xml @@ -0,0 +1,338 @@ +<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" +"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" +[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] > + +<chapter id='sdk-intro'> +<title>Introduction</title> + +<section id='sdk-manual-intro'> + <title>Introduction</title> + + <para> + Welcome to the Yocto Project Software Development Kit (SDK) + Developer's Guide. + This manual provides information that lets you use both the standard + Yocto Project SDK and an extensible SDK to develop applications and + images using the Yocto Project. + Additionally, the manual also provides information on how to use + the popular <trademark class='trade'>Eclipse</trademark> IDE as part + of your application development workflow. + </para> + + <para> + Prior to the 2.0 Release of the Yocto Project, application + development was primarily accomplished through the use of the + Application Development Toolkit (ADT) and the availability + of stand-alone cross-development toolchains and other tools. + With the 2.1 Release of the Yocto Project, application development + has transitioned to within a more traditional SDK and extensible + SDK. + </para> + + <para> + A standard SDK consists of a cross-development toolchain that contains + a compiler, debugger, and various miscellaneous tools; libraries, + headers, and symbols to match an image; and environment setup script. + You can use this SDK to independently develop and test code that is + destined to run on some target machine. + </para> + + <para> + An extensible SDK consists of everything that the standard SDK has plus + tools that allow you to easily add new applications and libraries to + an image, modify the source of an existing component, test changes on + the target hardware, and easily integrate an application into the + <ulink url='&YOCTO_DOCS_DEV_URL;#build-system-term'>OpenEmbedded build system</ulink>. + </para> + + <para> + SDKs are completely self-contained. + The binaries are linked against their own copy of + <filename>libc</filename>, which results in no dependencies + on the target system. + To achieve this, the pointer to the dynamic loader is + configured at install time since that path cannot be dynamically + altered. + This is the reason for a wrapper around the + <filename>populate_sdk</filename> and + <filename>populate_sdk_ext</filename> archives. + </para> + + <para> + Another feature for the SDKs is that only one set of cross-canadian + toolchain binaries are produced per architecture. + This feature takes advantage of the fact that the target hardware can + be passed to <filename>gcc</filename> as a set of compiler options. + Those options are set up by the environment script and contained in + variables such as + <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink> + and + <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'><filename>LD</filename></ulink>. + This reduces the space needed for the tools. + Understand, however, that a sysroot is still needed for every target + since those binaries are target-specific. + </para> + + <para> + Going beyond the actual SDK, the SDK development environment consists + of the following: + <itemizedlist> + <listitem><para>An architecture-specific cross-toolchain and + matching sysroots (target and native) all built by the + OpenEmbedded build system. + The toolchain and sysroots are based on a + <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink> + configuration and extensions, + which allows you to cross-develop on the host machine for the + target hardware. + </para></listitem> + <listitem><para>The Quick EMUlator (QEMU), which lets you simulate + target hardware. + QEMU is not literally part of the SDK. + You must build and include this emulator separately. + However, QEMU plays an important role in the development + process that revolves around use of and SDK. + </para></listitem> + <listitem><para>The Eclipse IDE Yocto Plug-in. + This plug-in is also available for you if you are an Eclipse + user. + In the same manner as QEMU, the plug-in is not literally part + of the SDK but is rather available for use as part of the + development process. + </para></listitem> + <listitem><para>Various user-space tools that greatly enhance + your application development experience. + These tools are also separate from the actual SDK but can be + independently obtained and used in the development process. + </para></listitem> + </itemizedlist> + </para> + + <section id='the-cross-development-toolchain'> + <title>The Cross-Development Toolchain</title> + + <para> + The + <ulink url='&YOCTO_DOCS_DEV_URL;#cross-development-toolchain'>Cross-Development Toolchain</ulink> + consists of a cross-compiler, cross-linker, and cross-debugger + that are used to develop user-space applications for targeted + hardware. + This toolchain is created by running a toolchain installer script + or through a + <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink> + that is based on your Metadata configuration or extension for + your targeted device. + The cross-toolchain works with a matching target sysroot. + </para> + </section> + + <section id='sysroot'> + <title>Sysroots</title> + + <para> + The native and target sysroots contain needed headers and libraries + for generating binaries that run on the target architecture. + The target sysroot is based on the target root filesystem image + that is built by the OpenEmbedded build system and uses the same + Metadata configuration used to build the cross-toolchain. + </para> + </section> + + <section id='the-qemu-emulator'> + <title>The QEMU Emulator</title> + + <para> + The QEMU emulator allows you to simulate your hardware while + running your application or image. + QEMU is not part of the SDK but is made available a number of ways: + <itemizedlist> + <listitem><para> + If you have cloned the <filename>poky</filename> Git + repository to create a + <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink> + and you have sourced the environment setup script, QEMU is + installed and automatically available. + </para></listitem> + <listitem><para> + If you have downloaded a Yocto Project release and unpacked + it to create a + <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink> + and you have sourced the environment setup script, QEMU is + installed and automatically available. + </para></listitem> + <listitem><para> + If you have installed the cross-toolchain tarball and you + have sourced the toolchain's setup environment script, QEMU + is also installed and automatically available. + </para></listitem> + </itemizedlist> + </para> + </section> + + <section id='eclipse-overview'> + <title>Eclipse Yocto Plug-in</title> + + <para> + The Eclipse IDE is a popular development environment and it fully + supports development using the Yocto Project. + When you install and configure the Eclipse Yocto Project Plug-in + into the Eclipse IDE, you maximize your Yocto Project experience. + Installing and configuring the Plug-in results in an environment + that has extensions specifically designed to let you more easily + develop software. + These extensions allow for cross-compilation, deployment, and + execution of your output into a QEMU emulation session. + You can also perform cross-debugging and profiling. + The environment also supports a suite of tools that allows you to + perform remote profiling, tracing, collection of power data, + collection of latency data, and collection of performance data. + </para> + + <para> + For information about the application development workflow that + uses the Eclipse IDE and for a detailed example of how to install + and configure the Eclipse Yocto Project Plug-in, see the + "<link link='sdk-developing-applications-using-eclipse'>Developing Applications Using <trademark class='trade'>Eclipse</trademark></link>" + section. + </para> + </section> + + <section id='user-space-tools'> + <title>User-Space Tools</title> + + <para> + User-space tools are available as part of the SDK development + process and can be helpful. + The tools include LatencyTOP, PowerTOP, Perf, SystemTap, + and Lttng-ust. + These tools are common development tools for the Linux platform. + <itemizedlist> + <listitem><para><emphasis>LatencyTOP:</emphasis> LatencyTOP + focuses on latency that causes skips in audio, stutters in + your desktop experience, or situations that overload your + server even when you have plenty of CPU power left. + </para></listitem> + <listitem><para><emphasis>PowerTOP:</emphasis> Helps you + determine what software is using the most power. + You can find out more about PowerTOP at + <ulink url='https://01.org/powertop/'></ulink>.</para></listitem> + <listitem><para><emphasis>Perf:</emphasis> Performance counters + for Linux used to keep track of certain types of hardware + and software events. + For more information on these types of counters see + <ulink url='https://perf.wiki.kernel.org/'></ulink>. + For examples on how to setup and use this tool, see the + "<ulink url='&YOCTO_DOCS_PROF_URL;#profile-manual-perf'>perf</ulink>" + section in the Yocto Project Profiling and Tracing Manual. + </para></listitem> + <listitem><para><emphasis>SystemTap:</emphasis> A free software + infrastructure that simplifies information gathering about + a running Linux system. + This information helps you diagnose performance or + functional problems. + SystemTap is not available as a user-space tool through + the Eclipse IDE Yocto Plug-in. + See <ulink url='http://sourceware.org/systemtap'></ulink> + for more information on SystemTap. + For examples on how to setup and use this tool, see the + "<ulink url='&YOCTO_DOCS_PROF_URL;#profile-manual-systemtap'>SystemTap</ulink>" + section in the Yocto Project Profiling and Tracing Manual. + </para></listitem> + <listitem><para><emphasis>Lttng-ust:</emphasis> A User-space + Tracer designed to provide detailed information on + user-space activity. + See <ulink url='http://lttng.org/ust'></ulink> for more + information on Lttng-ust. + </para></listitem> + </itemizedlist> + </para> + </section> +</section> + +<section id='sdk-development-model'> + <title>SDK Development Model</title> + + <para> + Fundamentally, the SDK fits into the development process as follows: + <imagedata fileref="figures/sdk-environment.png" align="center" width="6in" depth="5in" scalefit="100" /> + The SDK is installed on any machine and can be used to develop + applications, images, and kernels. + An SDK can even be used by a QA Engineer or Release Engineer. + The fundamental concept is that the machine that has the SDK installed + does not have to be associated with the machine that has the + Yocto Project installed. + A developer can independently compile and test an object on their + machine and then, when the object is ready for integration into an + image, they can simply make it available to the machine that has the + the Yocto Project. + Once the object is available, the image can be rebuilt using the + Yocto Project to produce the modified image. + </para> + + <para> + You just need to follow these general steps: + <orderedlist> + <listitem><para><emphasis>Install the SDK for your target hardware:</emphasis> + For information on how to install the SDK, see the + "<link url='sdk-installing-the-sdk'>Installing the SDK</link>" + section.</para></listitem> + <listitem><para><emphasis>Download the Target Image:</emphasis> + The Yocto Project supports several target architectures + and has many pre-built kernel images and root filesystem + images.</para> + <para>If you are going to develop your application on + hardware, go to the + <ulink url='&YOCTO_MACHINES_DL_URL;'><filename>machines</filename></ulink> + download area and choose a target machine area + from which to download the kernel image and root filesystem. + This download area could have several files in it that + support development using actual hardware. + For example, the area might contain + <filename>.hddimg</filename> files that combine the + kernel image with the filesystem, boot loaders, and + so forth. + Be sure to get the files you need for your particular + development process.</para> + <para>If you are going to develop your application and + then run and test it using the QEMU emulator, go to the + <ulink url='&YOCTO_QEMU_DL_URL;'><filename>machines/qemu</filename></ulink> + download area. + From this area, go down into the directory for your + target architecture (e.g. <filename>qemux86_64</filename> + for an <trademark class='registered'>Intel</trademark>-based + 64-bit architecture). + Download kernel, root filesystem, and any other files you + need for your process. + <note>In order to use the root filesystem in QEMU, you + need to extract it. + See the + "<link url='sdk-extracting-the-root-filesystem'>Extracting the Root Filesystem</link>" + section for information on how to extract the root + filesystem.</note></para></listitem> + <listitem><para><emphasis>Develop and Test your + Application:</emphasis> At this point, you have the tools + to develop your application. + If you need to separately install and use the QEMU + emulator, you can go to + <ulink url='http://wiki.qemu.org/Main_Page'>QEMU Home Page</ulink> + to download and learn about the emulator. + You can see the + "<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-qemu'>Using the Quick EMUlator (QEMU)</ulink>" + chapter in the Yocto Project Development Manual + for information on using QEMU within the Yocto + Project.</para></listitem> + </orderedlist> + </para> + + <para> + The remainder of this manual describes how to use both the standard + SDK and the extensible SDK. + Information also exists in appendix form that describes how you can + build, install, and modify an SDK. + </para> +</section> + +</chapter> +<!-- +vim: expandtab tw=80 ts=4 +--> |