diff options
| author |   Scott Rifenbark <scott.m.rifenbark@intel.com> | 2013-01-10 17:25:18 -0600 |
|---|---|---|
| committer |   Richard Purdie <richard.purdie@linuxfoundation.org> | 2013-01-27 13:54:08 +0000 |
| commit | 6b7ae329462115ef1d5ec70a212d1728f6c7acc4 (patch) | |
| tree | 10d000c71ff623e2d6d6f372d178c96e0c48d2bf /documentation/profile-manual/profile-manual-examples.xml | |
| parent | bc8c4165859482ae3afd9edce93815dee5d7b6c4 (diff) | |
| download | openembedded-core-contrib-6b7ae329462115ef1d5ec70a212d1728f6c7acc4.tar.gz | |
profile-manual: Added basic XML files and updated the .gitignore
Added four chapters to the directory. I based these chapters off
of an existing YP manual. I also updated the .gitignore file
so that it will support ingnoring profile-manual make operations.
(From yocto-docs rev: f9658f627fe9d8d6868ce74e9550ea16d23c4156)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation/profile-manual/profile-manual-examples.xml')
| -rw-r--r-- | documentation/profile-manual/profile-manual-examples.xml | 1915 |
1 files changed, 1915 insertions, 0 deletions
diff --git a/documentation/profile-manual/profile-manual-examples.xml b/documentation/profile-manual/profile-manual-examples.xml new file mode 100644 index 0000000000..442cab3036 --- /dev/null +++ b/documentation/profile-manual/profile-manual-examples.xml @@ -0,0 +1,1915 @@ +<!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='dev-manual-model'> + +<title>Common Development Models</title> + +<para> + Many development models exist for which you can use the Yocto Project. + This chapter overviews simple methods that use tools provided by the + Yocto Project: + <itemizedlist> + <listitem><para><emphasis>System Development:</emphasis> + System Development covers Board Support Package (BSP) development and kernel + modification or configuration. + For an example on how to create a BSP, see the + "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'>Creating a New BSP Layer Using the yocto-bsp Script</ulink>" + section in the Yocto Project Board Support Package (BSP) Developer's Guide. + </para></listitem> + <listitem><para><emphasis>User Application Development:</emphasis> + User Application Development covers development of applications that you intend + to run on some target hardware. + For information on how to set up your host development system for user-space + application development, see the + <ulink url='&YOCTO_DOCS_ADT_URL;'>Yocto Project Application Developer's Guide</ulink>. + For a simple example of user-space application development using the + <trademark class='trade'>Eclipse</trademark> IDE, see the + "<link linkend='application-development-workflow'>Application + Development Workflow</link>" section. + </para></listitem> + <listitem><para><emphasis>Temporary Source Code Modification:</emphasis> + Direct modification of temporary source code is a convenient development model + to quickly iterate and develop towards a solution. + Once the solution has been implemented, you should of course take steps to + get the changes upstream and applied in the affected recipes.</para></listitem> + <listitem><para><emphasis>Image Development using Hob:</emphasis> + You can use the <ulink url='&YOCTO_HOME_URL;/projects/hob'>Hob</ulink> to build + custom operating system images within the build environment. + Hob provides an efficient interface to the OpenEmbedded build system.</para></listitem> + <listitem><para><emphasis>Using a Development Shell:</emphasis> + You can use a <filename>devshell</filename> to efficiently debug commands or simply + edit packages. + Working inside a development shell is a quick way to set up the OpenEmbedded build + environment to work on parts of a project.</para></listitem> + </itemizedlist> +</para> + +<section id='system-development-model'> + <title>System Development Workflow</title> + + <para> + System development involves modification or creation of an image that you want to run on + a specific hardware target. + Usually, when you want to create an image that runs on embedded hardware, the image does + not require the same number of features that a full-fledged Linux distribution provides. + Thus, you can create a much smaller image that is designed to use only the + features for your particular hardware. + </para> + + <para> + To help you understand how system development works in the Yocto Project, this section + covers two types of image development: BSP creation and kernel modification or + configuration. + </para> + + <section id='developing-a-board-support-package-bsp'> + <title>Developing a Board Support Package (BSP)</title> + + <para> + A BSP is a package of recipes that, when applied during a build, results in + an image that you can run on a particular board. + Thus, the package when compiled into the new image, supports the operation of the board. + </para> + + <note> + For a brief list of terms used when describing the development process in the Yocto Project, + see the "<link linkend='yocto-project-terms'>Yocto Project Terms</link>" section. + </note> + + <para> + The remainder of this section presents the basic steps used to create a BSP + using the Yocto Project's + <ulink url='&YOCTO_DOCS_BSP_URL;#using-the-yocto-projects-bsp-tools'>BSP Tools</ulink>. + For an example that shows how to create a new layer using the tools, see the + "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'>Creating a New BSP Layer Using the yocto-bsp Script</ulink>" + section in the Yocto Project Board Support Package (BSP) Developer's Guide. + </para> + + <para> + The following illustration and list summarize the BSP creation general workflow. + </para> + + <para> + <imagedata fileref="figures/bsp-dev-flow.png" width="6in" depth="7in" align="center" scalefit="1" /> + </para> + + <para> + <orderedlist> + <listitem><para><emphasis>Set up your host development system to support + development using the Yocto Project</emphasis>: See the + "<ulink url='&YOCTO_DOCS_QS_URL;#the-linux-distro'>The Linux Distributions</ulink>" + and the + "<ulink url='&YOCTO_DOCS_QS_URL;#packages'>The Packages</ulink>" sections both + in the Yocto Project Quick Start for requirements.</para></listitem> + <listitem><para><emphasis>Establish a local copy of the project files on your + system</emphasis>: You need this <link linkend='source-directory'>Source + Directory</link> available on your host system. + Having these files on your system gives you access to the build + process and to the tools you need. + For information on how to set up the + <link linkend='source-directory'>Source Directory</link>, see the + "<link linkend='getting-setup'>Getting Setup</link>" section.</para></listitem> + <listitem><para><emphasis>Establish the <filename>meta-intel</filename> + repository on your system</emphasis>: Having local copies of the + supported BSP layers on your system gives you access to the build + process and to the tools you need for creating a BSP. + For information on how to get these files, see the + "<link linkend='getting-setup'>Getting Setup</link>" section.</para></listitem> + <listitem><para><emphasis>Create your own BSP layer using the + <ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'><filename>yocto-bsp</filename></ulink> script</emphasis>: + Layers are ideal for + isolating and storing work for a given piece of hardware. + A layer is really just a location or area in which you place the recipes for your BSP. + In fact, a BSP is, in itself, a special type of layer. + The simplest way to create a new BSP layer that is compliant with the + Yocto Project is to use the <filename>yocto-bsp</filename> script. + For information about that script, see the + "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'>Creating a New BSP Layer Using the yocto-bsp Script</ulink>" + section in the Yocto Project Board Support (BSP) Developer's Guide. + </para> + <para> + Another example that illustrates a layer is an application. + Suppose you are creating an application that has library or other dependencies in + order for it to compile and run. + The layer, in this case, would be where all the recipes that define those dependencies + are kept. + The key point for a layer is that it is an isolated area that contains + all the relevant information for the project that the OpenEmbedded build + system knows about. + For more information on layers, see the + "<link linkend='understanding-and-creating-layers'>Understanding and Creating Layers</link>" + section. + For more information on BSP layers, see the + "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>" section in the + Yocto Project Board Support Package (BSP) Developer's Guide.</para> + <note>Four BSPs exist that are part of the + Yocto Project release: <filename>atom-pc</filename>, <filename>beagleboard</filename>, + <filename>mpc8315e</filename>, and <filename>routerstationpro</filename>. + The recipes and configurations for these four BSPs are located and dispersed + within the <link linkend='source-directory'>Source Directory</link>. + On the other hand, BSP layers for Cedar Trail, Chief River, Crown Bay, + Crystal Forest, Emenlow, Fish River, Fish River 2, Jasper Forest, N450, + Romley, sys940x, Sugar Bay, and tlk exist in their own separate layers + within the larger <filename>meta-intel</filename> layer.</note> + <para>When you set up a layer for a new BSP, you should follow a standard layout. + This layout is described in the section + "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout'>Example Filesystem Layout</ulink>" + section of the Board Support Package (BSP) Development Guide. + In the standard layout, you will notice a suggested structure for recipes and + configuration information. + You can see the standard layout for a BSP by examining + any supported BSP found in the <filename>meta-intel</filename> layer inside + the Source Directory.</para></listitem> + <listitem><para><emphasis>Make configuration changes to your new BSP + layer</emphasis>: The standard BSP layer structure organizes the files you need + to edit in <filename>conf</filename> and several <filename>recipes-*</filename> + directories within the BSP layer. + Configuration changes identify where your new layer is on the local system + and identify which kernel you are going to use. + When you run the <filename>yocto-bsp</filename> script you are able to interactively + configure many things for the BSP (e.g. keyboard, touchscreen, and so forth). + </para></listitem> + <listitem><para><emphasis>Make recipe changes to your new BSP layer</emphasis>: Recipe + changes include altering recipes (<filename>.bb</filename> files), removing + recipes you don't use, and adding new recipes or append files + (<filename>.bbappend</filename>) that you need to support your hardware. + </para></listitem> + <listitem><para><emphasis>Prepare for the build</emphasis>: Once you have made all the + changes to your BSP layer, there remains a few things + you need to do for the OpenEmbedded build system in order for it to create your image. + You need to get the build environment ready by sourcing an environment setup script + and you need to be sure two key configuration files are configured appropriately: + the <filename>conf/local.conf</filename> and the + <filename>conf/bblayers.conf</filename> file. + You must make the OpenEmbedded build system aware of your new layer. + See the + "<link linkend='enabling-your-layer'>Enabling Your Layer</link>" section + for information on how to let the build system know about your new layer.</para> + <para>The entire process for building an image is overviewed in the section + "<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>" section + of the Yocto Project Quick Start. + You might want to reference this information.</para></listitem> + <listitem><para><emphasis>Build the image</emphasis>: The OpenEmbedded build system + uses the BitBake tool to build images based on the type of image you want to create. + You can find more information about BitBake in the user manual, which is found in the + <filename>bitbake/doc/manual</filename> directory of the + <link linkend='source-directory'>Source Directory</link>.</para> + <para>The build process supports several types of images to satisfy different needs. + See the + "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>" chapter + in the Yocto Project Reference Manual for information on + supported images.</para></listitem> + </orderedlist> + </para> + + <para> + You can view a video presentation on "Building Custom Embedded Images with Yocto" + at <ulink url='http://free-electrons.com/blog/elc-2011-videos'>Free Electrons</ulink>. + You can also find supplemental information in + <ulink url='&YOCTO_DOCS_BSP_URL;'> + The Board Support Package (BSP) Development Guide</ulink>. + Finally, there is wiki page write up of the example also located + <ulink url='&YOCTO_WIKI_URL;/wiki/Transcript:_creating_one_generic_Atom_BSP_from_another'> + here</ulink> that you might find helpful. + </para> + </section> + + <section id='modifying-the-kernel'> + <title><anchor id='kernel-spot' />Modifying the Kernel</title> + + <para> + Kernel modification involves changing the Yocto Project kernel, which could involve changing + configuration options as well as adding new kernel recipes. + Configuration changes can be added in the form of configuration fragments, while recipe + modification comes through the kernel's <filename>recipes-kernel</filename> area + in a kernel layer you create. + </para> + + <para> + The remainder of this section presents a high-level overview of the Yocto Project + kernel architecture and the steps to modify the kernel. + For a complete discussion of the kernel, see the + <ulink url='&YOCTO_DOCS_KERNEL_URL;'>Yocto Project Kernel Architecture and Use Manual</ulink>. + You can reference the + "<link linkend='patching-the-kernel'>Patching the Kernel</link>" section + for an example that changes the source code of the kernel. + For information on how to configure the kernel, see the + "<link linkend='configuring-the-kernel'>Configuring the Kernel</link>" section. + </para> + + <section id='kernel-overview'> + <title>Kernel Overview</title> + + <para> + Traditionally, when one thinks of a patched kernel, they think of a base kernel + source tree and a fixed structure that contains kernel patches. + The Yocto Project, however, employs mechanisms, that in a sense, result in a kernel source + generator. + By the end of this section, this analogy will become clearer. + </para> + + <para> + You can find a web interface to the Yocto Project kernel source repositories at + <ulink url='&YOCTO_GIT_URL;'></ulink>. + If you look at the interface, you will see to the left a grouping of + Git repositories titled "Yocto Linux Kernel." + Within this group, you will find several kernels supported by + the Yocto Project: + <itemizedlist> + <listitem><para><emphasis><filename>linux-yocto-2.6.34</filename></emphasis> - The + stable Yocto Project kernel that is based on the Linux 2.6.34 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-2.6.37</filename></emphasis> - The + stable Yocto Project kernel that is based on the Linux 2.6.37 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-3.0</filename></emphasis> - The stable + Yocto Project kernel that is based on the Linux 3.0 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-3.0-1.1.x</filename></emphasis> - The + stable Yocto Project kernel to use with the Yocto Project Release 1.1.x. This kernel + is based on the Linux 3.0 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-3.2</filename></emphasis> - The + stable Yocto Project kernel to use with the Yocto Project Release 1.2. This kernel + is based on the Linux 3.2 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-3.4</filename></emphasis> - The + stable Yocto Project kernel to use with the Yocto Project Release 1.3. This kernel + is based on the Linux 3.4 released kernel.</para></listitem> + <listitem><para><emphasis><filename>linux-yocto-dev</filename></emphasis> - A development + kernel based on the latest upstream release candidate available.</para></listitem> + </itemizedlist> + </para> + + <para> + The kernels are maintained using the Git revision control system + that structures them using the familiar "tree", "branch", and "leaf" scheme. + Branches represent diversions from general code to more specific code, while leaves + represent the end-points for a complete and unique kernel whose source files + when gathered from the root of the tree to the leaf accumulate to create the files + necessary for a specific piece of hardware and its features. + The following figure displays this concept: + <para> + <imagedata fileref="figures/kernel-overview-1.png" + width="6in" depth="6in" align="center" scale="100" /> + </para> + + <para> + Within the figure, the "Kernel.org Branch Point" represents the point in the tree + where a supported base kernel is modified from the Linux kernel. + For example, this could be the branch point for the <filename>linux-yocto-3.0</filename> + kernel. + Thus, everything further to the right in the structure is based on the + <filename>linux-yocto-3.0</filename> kernel. + Branch points to right in the figure represent where the + <filename>linux-yocto-3.0</filename> kernel is modified for specific hardware + or types of kernels, such as real-time kernels. + Each leaf thus represents the end-point for a kernel designed to run on a specific + targeted device. + </para> + + <para> + The overall result is a Git-maintained repository from which all the supported + kernel types can be derived for all the supported devices. + A big advantage to this scheme is the sharing of common features by keeping them in + "larger" branches within the tree. + This practice eliminates redundant storage of similar features shared among kernels. + </para> + + <note> + Keep in mind the figure does not take into account all the supported Yocto + Project kernel types, but rather shows a single generic kernel just for conceptual purposes. + Also keep in mind that this structure represents the Yocto Project source repositories + that are either pulled from during the build or established on the host development system + prior to the build by either cloning a particular kernel's Git repository or by + downloading and unpacking a tarball. + </note> + + <para> + Upstream storage of all the available kernel source code is one thing, while + representing and using the code on your host development system is another. + Conceptually, you can think of the kernel source repositories as all the + source files necessary for all the supported kernels. + As a developer, you are just interested in the source files for the kernel on + on which you are working. + And, furthermore, you need them available on your host system. + </para> + + <para> + Kernel source code is available on your host system a couple of different + ways. + If you are working in the kernel all the time, you probably would want + to set up your own local Git repository of the kernel tree. + If you just need to make some patches to the kernel, you can get at + temporary kernel source files extracted and used during the OpenEmbedded + build system. + We will just talk about working with the temporary source code. + </para> + + <para> + What happens during the build? + When you build the kernel on your development system, all files needed for the build + are taken from the source repositories pointed to by the + <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink> variable + and gathered in a temporary work area + where they are subsequently used to create the unique kernel. + Thus, in a sense, the process constructs a local source tree specific to your + kernel to generate the new kernel image - a source generator if you will. + </para> + The following figure shows the temporary file structure + created on your host system when the build occurs. + This + <link linkend='build-directory'>Build Directory</link> contains all the + source files used during the build. + </para> + + <para> + <imagedata fileref="figures/kernel-overview-2-generic.png" + width="6in" depth="5in" align="center" scale="100" /> + </para> + + <para> + Again, for a complete discussion of the Yocto Project kernel's architecture and its + branching strategy, see the + <ulink url='&YOCTO_DOCS_KERNEL_URL;'>Yocto Project Kernel Architecture and Use Manual</ulink>. + You can also reference the + "<link linkend='patching-the-kernel'>Patching the Kernel</link>" + section for a detailed example that modifies the kernel. + </para> + </section> + + <section id='kernel-modification-workflow'> + <title>Kernel Modification Workflow</title> + + <para> + This illustration and the following list summarizes the kernel modification general workflow. + </para> + + <para> + <imagedata fileref="figures/kernel-dev-flow.png" + width="6in" depth="5in" align="center" scalefit="1" /> + </para> + + <para> + <orderedlist> + <listitem><para><emphasis>Set up your host development system to support + development using the Yocto Project</emphasis>: See + "<ulink url='&YOCTO_DOCS_QS_URL;#the-linux-distro'>The Linux Distributions</ulink>" and + "<ulink url='&YOCTO_DOCS_QS_URL;#packages'>The Packages</ulink>" sections both + in the Yocto Project Quick Start for requirements.</para></listitem> + <listitem><para><emphasis>Establish a local copy of project files on your + system</emphasis>: Having the <link linkend='source-directory'>Source + Directory</link> on your system gives you access to the build process and tools + you need. + For information on how to get these files, see the bulleted item + "<link linkend='local-yp-release'>Yocto Project Release</link>" earlier in this manual. + </para></listitem> + <listitem><para><emphasis>Establish the temporary kernel source files</emphasis>: + Temporary kernel source files are kept in the Build Directory created by the + OpenEmbedded build system when you run BitBake. + If you have never built the kernel you are interested in, you need to run + an initial build to establish local kernel source files.</para> + <para>If you are building an image for the first time, you need to get the build + environment ready by sourcing + the environment setup script. + You also need to be sure two key configuration files + (<filename>local.conf</filename> and <filename>bblayers.conf</filename>) + are configured appropriately.</para> + <para>The entire process for building an image is overviewed in the + "<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>" + section of the Yocto Project Quick Start. + You might want to reference this information. + You can find more information on BitBake in the user manual, which is found in the + <filename>bitbake/doc/manual</filename> directory of the + <link linkend='source-directory'>Source Directory</link>.</para> + <para>The build process supports several types of images to satisfy different needs. + See the "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>" chapter in + the Yocto Project Reference Manual for information on supported images. + </para></listitem> + <listitem><para><emphasis>Make changes to the kernel source code if + applicable</emphasis>: Modifying the kernel does not always mean directly + changing source files. + However, if you have to do this, you make the changes to the files in the + Build directory.</para></listitem> + <listitem><para><emphasis>Make kernel configuration changes + if applicable</emphasis>: + If your situation calls for changing the kernel's configuration, you can + use the <filename>yocto-kernel</filename> script or <filename>menuconfig</filename> + to enable and disable kernel configurations. + Using the script lets you interactively set up kernel configurations. + Using <filename>menuconfig</filename> allows you to interactively develop and test the + configuration changes you are making to the kernel. + When saved, changes using <filename>menuconfig</filename> update the kernel's + <filename>.config</filename>. + Try to resist the temptation of directly editing the <filename>.config</filename> + file found in the + <link linkend='build-directory'>Build Directory</link> at + <filename>tmp/sysroots/<machine-name>/kernel</filename>. + Doing so, can produce unexpected results when the OpenEmbedded build system + regenerates the configuration file.</para> + <para>Once you are satisfied with the configuration changes made using + <filename>menuconfig</filename>, you can directly examine the + <filename>.config</filename> file against a saved original and gather those + changes into a config fragment to be referenced from within the kernel's + <filename>.bbappend</filename> file.</para></listitem> + <listitem><para><emphasis>Rebuild the kernel image with your changes</emphasis>: + Rebuilding the kernel image applies your changes.</para></listitem> + </orderedlist> + </para> + </section> + </section> +</section> + +<section id='application-development-workflow'> + <title>Application Development Workflow</title> + + <para> + Application development involves creating an application that you want + to run on your target hardware, which is running a kernel image created using the + OpenEmbedded build system. + The Yocto Project provides an Application Development Toolkit (ADT) and + stand-alone cross-development toolchains that + facilitate quick development and integration of your application into its run-time environment. + Using the ADT and toolchains, you can compile and link your application. + You can then deploy your application to the actual hardware or to the QEMU emulator for testing. + If you are familiar with the popular <trademark class='trade'>Eclipse</trademark> IDE, + you can use an Eclipse Yocto Plug-in to + allow you to develop, deploy, and test your application all from within Eclipse. + </para> + + <para> + While we strongly suggest using the ADT to develop your application, this option might not + be best for you. + If this is the case, you can still use pieces of the Yocto Project for your development process. + However, because the process can vary greatly, this manual does not provide detail on the process. + </para> + + <section id='workflow-using-the-adt-and-eclipse'> + <title>Workflow Using the ADT and <trademark class='trade'>Eclipse</trademark></title> + + <para> + To help you understand how application development works using the ADT, this section + provides an overview of the general development process and a detailed example of the process + as it is used from within the Eclipse IDE. + </para> + + <para> + The following illustration and list summarize the application development general workflow. + </para> + + <para> + <imagedata fileref="figures/app-dev-flow.png" + width="7in" depth="8in" align="center" scale="100" /> + </para> + + <para> + <orderedlist> + <listitem><para><emphasis>Prepare the Host System for the Yocto Project</emphasis>: + See + "<ulink url='&YOCTO_DOCS_QS_URL;#the-linux-distro'>The Linux Distributions</ulink>" and + "<ulink url='&YOCTO_DOCS_QS_URL;#packages'>The Packages</ulink>" sections both + in the Yocto Project Quick Start for requirements.</para></listitem> + <listitem><para><emphasis>Secure the Yocto Project Kernel Target Image</emphasis>: + You must have a target kernel image that has been built using the OpenEmbeded + build system.</para> + <para>Depending on whether the Yocto Project has a pre-built image that matches your target + architecture and where you are going to run the image while you develop your application + (QEMU or real hardware), the area from which you get the image differs. + <itemizedlist> + <listitem><para>Download the image from + <ulink url='&YOCTO_MACHINES_DL_URL;'><filename>machines</filename></ulink> + if your target architecture is supported and you are going to develop + and test your application on actual hardware.</para></listitem> + <listitem><para>Download the image from the + <ulink url='&YOCTO_QEMU_DL_URL;'> + <filename>machines/qemu</filename></ulink> if your target architecture is supported + and you are going to develop and test your application using the QEMU + emulator.</para></listitem> + <listitem><para>Build your image if you cannot find a pre-built image that matches + your target architecture. + If your target architecture is similar to a supported architecture, you can + modify the kernel image before you build it. + See the + "<link linkend='patching-the-kernel'>Patching the Kernel</link>" + section for an example.</para></listitem> + </itemizedlist></para> + <para>For information on pre-built kernel image naming schemes for images + that can run on the QEMU emulator, see the + "<ulink url='&YOCTO_DOCS_QS_URL;#downloading-the-pre-built-linux-kernel'>Downloading the Pre-Built Linux Kernel</ulink>" + section in the Yocto Project Quick Start.</para></listitem> + <listitem><para><emphasis>Install the ADT</emphasis>: + The ADT provides a target-specific cross-development toolchain, the root filesystem, + the QEMU emulator, and other tools that can help you develop your application. + While it is possible to get these pieces separately, the ADT Installer provides an + easy method. + You can get these pieces by running an ADT installer script, which is configurable. + For information on how to install the ADT, see the + "<ulink url='&YOCTO_DOCS_ADT_URL;#using-the-adt-installer'>Using the ADT Installer</ulink>" + section + in the Yocto Project Application Developer's Guide.</para></listitem> + <listitem><para><emphasis>If Applicable, Secure the Target Root Filesystem + and the Cross-development Toolchain</emphasis>: + If you choose not to install the ADT using the ADT Installer, + you need to find and download the appropriate root filesystem and + the cross-development toolchain.</para> + <para>You can find the tarballs for the root filesystem in the same area used + for the kernel image. + Depending on the type of image you are running, the root filesystem you need differs. + For example, if you are developing an application that runs on an image that + supports Sato, you need to get root filesystem that supports Sato.</para> + <para>You can find the cross-development toolchains at + <ulink url='&YOCTO_TOOLCHAIN_DL_URL;'><filename>toolchains</filename></ulink>. + Be sure to get the correct toolchain for your development host and your + target architecture. + See the "<ulink url='&YOCTO_DOCS_ADT_URL;#using-an-existing-toolchain-tarball'>Using a Cross-Toolchain Tarball</ulink>" + section in the Yocto Project Application Developer's Guide for information + and the + "<ulink url='&YOCTO_DOCS_QS_URL;#installing-the-toolchain'>Installing the Toolchain</ulink>" + in the Yocto Project Quick Start for information on finding and installing + the correct toolchain based on your host development system and your target + architecture. + </para></listitem> + <listitem><para><emphasis>Create and Build your Application</emphasis>: + At this point, you need to have source files for your application. + Once you have the files, you can use the Eclipse IDE to import them and build the + project. + If you are not using Eclipse, you need to use the cross-development tools you have + installed to create the image.</para></listitem> + <listitem><para><emphasis>Deploy the Image with the Application</emphasis>: + If you are using the Eclipse IDE, you can deploy your image to the hardware or to + QEMU through the project's preferences. + If you are not using the Eclipse IDE, then you need to deploy the application + to the hardware using other methods. + Or, if you are using QEMU, you need to use that tool and load your image in for testing. + </para></listitem> + <listitem><para><emphasis>Test and Debug the Application</emphasis>: + Once your application is deployed, you need to test it. + Within the Eclipse IDE, you can use the debugging environment along with the + set of user-space tools installed along with the ADT to debug your application. + Of course, the same user-space tools are available separately if you choose + not to use the Eclipse IDE.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='adt-eclipse'> + <title>Working Within Eclipse</title> + + <para> + The Eclipse IDE is a popular development environment and it fully supports + development using the Yocto Project. + <note>This release of the Yocto Project supports both the Juno and Indigo versions + of the Eclipse IDE. + Thus, the following information provides setup information for both versions. + </note> + </para> + + <para> + 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> + This section describes how to install and configure the Eclipse IDE + Yocto Plug-in and how to use it to develop your application. + </para> + + <section id='setting-up-the-eclipse-ide'> + <title>Setting Up the Eclipse IDE</title> + + <para> + To develop within the Eclipse IDE, you need to do the following: + <orderedlist> + <listitem><para>Install the optimal version of the Eclipse IDE.</para></listitem> + <listitem><para>Configure the Eclipse IDE.</para></listitem> + <listitem><para>Install the Eclipse Yocto Plug-in.</para></listitem> + <listitem><para>Configure the Eclipse Yocto Plug-in.</para></listitem> + </orderedlist> + <note> + Do not install Eclipse from your distribution's package repository. + Be sure to install Eclipse from the official Eclipse download site as directed + in the next section. + </note> + </para> + + <section id='installing-eclipse-ide'> + <title>Installing the Eclipse IDE</title> + + <para> + It is recommended that you have the Juno 4.2 version of the + Eclipse IDE installed on your development system. + However, if you currently have the Indigo 3.7.2 version installed and you do + not want to upgrade the IDE, you can configure Indigo to work with the + Yocto Project. + See the + "<link linkend='configuring-the-eclipse-ide-indigo'>Configuring the Eclipse IDE (Indigo)</link>" + section. + </para> + + <para> + If you don’t have the Juno 4.2 Eclipse IDE installed, you can find the tarball at + <ulink url='&ECLIPSE_MAIN_URL;'></ulink>. + From that site, choose the Eclipse Classic version particular to your development + host. + This version contains the Eclipse Platform, the Java Development + Tools (JDT), and the Plug-in Development Environment. + </para> + + <para> + Once you have downloaded the tarball, extract it into a clean + directory. + For example, the following commands unpack and install the + downloaded Eclipse IDE tarball into a clean directory + using the default name <filename>eclipse</filename>: + <literallayout class='monospaced'> + $ cd ~ + $ tar -xzvf ~/Downloads/eclipse-SDK-4.2-linux-gtk-x86_64.tar.gz + </literallayout> + </para> + + <para> + If you have the Indigo 3.7.2 Eclipse IDE already installed and you want to use that + version, one issue exists that you need to be aware of regarding the Java + Virtual machine’s garbage collection (GC) process. + The GC process does not clean up the permanent generation + space (PermGen). + This space stores metadata descriptions of classes. + The default value is set too small and it could trigger an + out-of-memory error such as the following: + <literallayout class='monospaced'> + Java.lang.OutOfMemoryError: PermGen space + </literallayout> + </para> + + <para> + This error causes the application to hang. + </para> + + <para> + To fix this issue, you can use the <filename>--vmargs</filename> + option when you start the Indigo 3.7.2 Eclipse IDE + to increase the size of the permanent generation space: + <literallayout class='monospaced'> + eclipse --vmargs --XX:PermSize=256M + </literallayout> + </para> + </section> + + <section id='configuring-the-eclipse-ide-juno'> + <title>Configuring the Eclipse IDE (Juno)</title> + + <para> + This section presents the steps needed to configure the Juno 4.2 Eclipse IDE. + If you are using Indigo 3.7.2, see the + "<link linkend='configuring-the-eclipse-ide-indigo'>Configuring the Eclipse IDE (Indigo)</link>". + </para> + + <para> + Before installing and configuring the Eclipse Yocto Plug-in, you need to configure + the Juno 4.2 Eclipse IDE. + Follow these general steps: + <orderedlist> + <listitem><para>Start the Eclipse IDE.</para></listitem> + <listitem><para>Make sure you are in your Workbench and select + "Install New Software" from the "Help" pull-down menu. + </para></listitem> + <listitem><para>Select <filename>Juno - &ECLIPSE_JUNO_URL;</filename> + from the "Work with:" pull-down menu.</para></listitem> + <listitem><para>Expand the box next to "Linux Tools" and select the + "LTTng - Linux Tracing Toolkit" boxes.</para></listitem> + <listitem><para>Expand the box next to "Mobile and Device Development" and select the + following boxes: + <itemizedlist> + <listitem><para><filename>C/C++ Remote Launch</filename></para></listitem> + <listitem><para><filename>Remote System Explorer End-user Runtime</filename></para></listitem> + <listitem><para><filename>Remote System Explorer User Actions</filename></para></listitem> + <listitem><para><filename>Target Management Terminal</filename></para></listitem> + <listitem><para><filename>TCF Remote System Explorer add-in</filename></para></listitem> + <listitem><para><filename>TCF Target Explorer</filename></para></listitem> + </itemizedlist></para></listitem> + <listitem><para>Expand the box next to <filename>Programming Languages</filename> + and select the <filename>Autotools Support for CDT</filename> + and <filename>C/C++ Development Tools</filename> boxes.</para></listitem> + <listitem><para>Complete the installation and restart the Eclipse IDE.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='configuring-the-eclipse-ide-indigo'> + <title>Configuring the Eclipse IDE (Indigo)</title> + + <para> + This section presents the steps needed to configure the Indigo 3.7.2 Eclipse IDE. + If you are using Juno 4.2, see the + "<link linkend='configuring-the-eclipse-ide-juno'>Configuring the Eclipse IDE (Juno)</link>". + </para> + + <para> + Before installing and configuring the Eclipse Yocto Plug-in, you need to configure + the Indigo 3.7.2 Eclipse IDE. + Follow these general steps: + <orderedlist> + <listitem><para>Start the Eclipse IDE.</para></listitem> + <listitem><para>Make sure you are in your Workbench and select + "Install New Software" from the "Help" pull-down menu. + </para></listitem> + <listitem><para>Select <filename>indigo - &ECLIPSE_INDIGO_URL;</filename> + from the "Work with:" pull-down menu.</para></listitem> + <listitem><para>Expand the box next to <filename>Programming Languages</filename> + and select the <filename>Autotools Support for CDT (incubation)</filename> + and <filename>C/C++ Development Tools</filename> boxes.</para></listitem> + <listitem><para>Expand the box next to "Linux Tools" and select the + "LTTng - Linux Tracing Toolkit(incubation)" boxes.</para></listitem> + <listitem><para>Complete the installation and restart the Eclipse IDE.</para></listitem> + <listitem><para>After the Eclipse IDE restarts and from the Workbench, select + "Install New Software" from the "Help" pull-down menu.</para></listitem> + <listitem><para>Click the + "Available Software Sites" link.</para></listitem> + <listitem><para>Check the box next to + <filename>&ECLIPSE_UPDATES_URL;</filename> + and click "OK".</para></listitem> + <listitem><para>Select <filename>&ECLIPSE_UPDATES_URL;</filename> + from the "Work with:" pull-down menu.</para></listitem> + <listitem><para>Check the box next to <filename>TM and RSE Main Features</filename>. + </para></listitem> + <listitem><para>Expand the box next to <filename>TM and RSE Optional Add-ons</filename> + and select every item except <filename>RSE Unit Tests</filename> and + <filename>RSE WinCE Services (incubation)</filename>.</para></listitem> + <listitem><para>Complete the installation and restart the Eclipse IDE.</para></listitem> + <listitem><para>If necessary, select + "Install New Software" from the "Help" pull-down menu so you can click the + "Available Software Sites" link again.</para></listitem> + <listitem><para>After clicking "Available Software Sites", check the box next to + <filename>http://download.eclipse.org/tools/cdt/releases/indigo</filename> + and click "OK".</para></listitem> + <listitem><para>Select <filename>&ECLIPSE_INDIGO_CDT_URL;</filename> + from the "Work with:" pull-down menu.</para></listitem> + <listitem><para>Check the box next to <filename>CDT Main Features</filename>. + </para></listitem> + <listitem><para>Expand the box next to <filename>CDT Optional Features</filename> + and select <filename>C/C++ Remote Launch</filename> and + <filename>Target Communication Framework (incubation)</filename>.</para></listitem> + <listitem><para>Complete the installation and restart the Eclipse IDE.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='installing-the-eclipse-yocto-plug-in'> + <title>Installing or Accessing the Eclipse Yocto Plug-in</title> + + <para> + You can install the Eclipse Yocto Plug-in into the Eclipse IDE + one of two ways: use the Yocto Project's Eclipse Update site to install the pre-built plug-in, + or build and install the plug-in from the latest source code. + If you don't want to permanently install the plug-in but just want to try it out + within the Eclipse environment, you can import the plug-in project from the + Yocto Project's Source Repositories. + </para> + + <section id='new-software'> + <title>Installing the Pre-built Plug-in from the Yocto Project Eclipse Update Site</title> + + <para> + To install the Eclipse Yocto Plug-in from the update site, + follow these steps: + <orderedlist> + <listitem><para>Start up the Eclipse IDE.</para></listitem> + <listitem><para>In Eclipse, select "Install New Software" from the "Help" menu.</para></listitem> + <listitem><para>Click "Add..." in the "Work with:" area.</para></listitem> + <listitem><para>Enter + <filename>&ECLIPSE_DL_PLUGIN_URL;</filename> + in the URL field and provide a meaningful name in the "Name" field.</para></listitem> + <listitem><para>Click "OK" to have the entry added to the "Work with:" + drop-down list.</para></listitem> + <listitem><para>Select the entry for the plug-in from the "Work with:" drop-down + list.</para></listitem> + <listitem><para>Check the box next to <filename>Development tools and SDKs for Yocto Linux</filename>. + </para></listitem> + <listitem><para>Complete the remaining software installation steps and + then restart the Eclipse IDE to finish the installation of the plug-in. + </para></listitem> + </orderedlist> + </para> + </section> + + <section id='zip-file-method'> + <title>Installing the Plug-in Using the Latest Source Code</title> + + <para> + To install the Eclipse Yocto Plug-in from the latest source code, follow these steps: + <orderedlist> + <listitem><para>Open a shell and create a Git repository with: + <literallayout class='monospaced'> + $ git clone git://git.yoctoproject.org/eclipse-poky yocto-eclipse + </literallayout> + For this example, the repository is named + <filename>~/yocto-eclipse</filename>.</para></listitem> + <listitem><para>Change to the directory where you set up + the Git repository: + <literallayout class='monospaced'> + $ cd ~/yocto-eclipse + </literallayout></para></listitem> + <listitem><para>Be sure you are in the right branch for your Git repository. + For this release set the branch to <filename>&DISTRO_NAME;</filename>: + <literallayout class='monospaced'> + $ git checkout -b &DISTRO_NAME; origin/&DISTRO_NAME; + </literallayout></para></listitem> + <listitem><para>Change to the <filename>scripts</filename> + directory within the Git repository: + <literallayout class='monospaced'> + $ cd scripts + </literallayout></para></listitem> + <listitem><para>Set up the local build environment by running the + setup script: + <literallayout class='monospaced'> + $ ./setup.sh + </literallayout></para></listitem> + <listitem><para>When the script finishes execution, it prompts + you with instructions on how to run the + <filename>build.sh</filename> script, which is also in + the <filename>scripts</filename> of the + Git repository created earlier. + </para></listitem> + <listitem><para>Run the <filename>build.sh</filename> script + as directed. + Be sure to provide the name of the Git branch along with the + Yocto Project release you are using. + Here is an example that uses the <filename>&DISTRO_NAME;</filename> branches: + <literallayout class='monospaced'> + $ ECLIPSE_HOME=/home/scottrif/yocto-eclipse/scripts/eclipse ./build.sh &DISTRO_NAME; &DISTRO_NAME; + </literallayout> + After running the script, the file + <filename>org.yocto.sdk-<release>-<date>-archive.zip</filename> + is in the current directory.</para></listitem> + <listitem><para>If necessary, start the Eclipse IDE and be sure you are in the + Workbench.</para></listitem> + <listitem><para>Select "Install New Software" from the "Help" pull-down menu. + </para></listitem> + <listitem><para>Click "Add".</para></listitem> + <listitem><para>Provide anything you want in the "Name" field.</para></listitem> + <listitem><para>Click "Archive" and browse to the ZIP file you built + in step seven. + This ZIP file should not be "unzipped", and must be the + <filename>*archive.zip</filename> file created by running the + <filename>build.sh</filename> script.</para></listitem> + <listitem><para>Click through the "Okay" buttons.</para></listitem> + <listitem><para>Check the box next to the new entry in the installation window and complete + the installation.</para></listitem> + <listitem><para>Restart the Eclipse IDE if necessary.</para></listitem> + </orderedlist> + </para> + + <para> + At this point you should be able to configure the Eclipse Yocto Plug-in as described in the + "<link linkend='configuring-the-eclipse-yocto-plug-in'>Configuring the Eclipse Yocto Plug-in</link>" + section.</para> + </section> + + <section id='yocto-project-source'> + <title>Importing the Plug-in Project into the Eclipse Environment</title> + + <para> + Importing the Eclipse Yocto Plug-in project from the Yocto Project source repositories + is useful when you want to try out the latest plug-in from the tip of plug-in's + development tree. + It is important to understand when you import the plug-in you are not installing + it into the Eclipse application. + Rather, you are importing the project and just using it. + To import the plug-in project, follow these steps: + <orderedlist> + <listitem><para>Open a shell and create a Git repository with: + <literallayout class='monospaced'> + $ git clone git://git.yoctoproject.org/eclipse-poky yocto-eclipse + </literallayout> + For this example, the repository is named + <filename>~/yocto-eclipse</filename>.</para></listitem> + <listitem><para>In Eclipse, select "Import" from the "File" menu.</para></listitem> + <listitem><para>Expand the "General" box and select "existing projects into workspace" + and then click "Next".</para></listitem> + <listitem><para>Select the root directory and browse to + <filename>~/yocto-eclipse/plugins</filename>.</para></listitem> + <listitem><para>Three plug-ins exist: "org.yocto.bc.ui", "org.yocto.sdk.ide", and + "org.yocto.sdk.remotetools". + Select and import all of them.</para></listitem> + </orderedlist> + </para> + + <para> + The left navigation pane in the Eclipse application shows the default projects. + Right-click on one of these projects and run it as an Eclipse application. + This brings up a second instance of Eclipse IDE that has the Yocto Plug-in. + </para> + </section> + </section> + + <section id='configuring-the-eclipse-yocto-plug-in'> + <title>Configuring the Eclipse Yocto Plug-in</title> + + <para> + Configuring the Eclipse Yocto Plug-in involves setting the Cross + Compiler options and the Target options. + The configurations you choose become the default settings for all projects. + You do have opportunities to change them later when + you configure the project (see the following section). + </para> + + <para> + To start, you need to do the following from within the Eclipse IDE: + <itemizedlist> + <listitem><para>Choose <filename>Windows -> Preferences</filename> to display + the <filename>Preferences</filename> Dialog</para></listitem> + <listitem><para>Click <filename>Yocto Project ADT</filename></para></listitem> + </itemizedlist> + </para> + + <section id='configuring-the-cross-compiler-options'> + <title>Configuring the Cross-Compiler Options</title> + + <para> + To configure the Cross Compiler Options, you must select the type of toolchain, + point to the toolchain, specify the sysroot location, and select the target architecture. + <itemizedlist> + <listitem><para><emphasis>Selecting the Toolchain Type:</emphasis> + Choose between <filename>Standalone pre-built toolchain</filename> + and <filename>Build system derived toolchain</filename> for Cross + Compiler Options. + <itemizedlist> + <listitem><para><emphasis> + <filename>Standalone Pre-built Toolchain:</filename></emphasis> + Select this mode when you are using a stand-alone cross-toolchain. + For example, suppose you are an application developer and do not + need to build a target image. + Instead, you just want to use an architecture-specific toolchain on an + existing kernel and target root filesystem. + </para></listitem> + <listitem><para><emphasis> + <filename>Build System Derived Toolchain:</filename></emphasis> + Select this mode if the cross-toolchain has been installed and built + as part of the Build Directory. + When you select <filename>Build system derived toolchain</filename>, + you are using the toolchain bundled + inside the Build Directory. + </para></listitem> + </itemizedlist> + </para></listitem> + <listitem><para><emphasis>Point to the Toolchain:</emphasis> + If you are using a stand-alone pre-built toolchain, you should be pointing to the + <filename>&YOCTO_ADTPATH_DIR;</filename> directory. + This is the location for toolchains installed by the ADT Installer or by hand. + Sections "<ulink url='&YOCTO_DOCS_ADT_URL;#configuring-and-running-the-adt-installer-script'>Configuring + and Running the ADT Installer Script</ulink>" and + "<ulink url='&YOCTO_DOCS_ADT_URL;#using-an-existing-toolchain-tarball'>Using a Cross-Toolchain Tarball</ulink>" + in the Yocto Project Application Developer's Guide + describe two ways to install a stand-alone cross-toolchain in the + <filename>/opt/poky</filename> directory. + <note>It is possible to install a stand-alone cross-toolchain in a directory + other than <filename>/opt/poky</filename>. + However, doing so is discouraged.</note></para> + <para>If you are using a system-derived toolchain, the path you provide + for the <filename>Toolchain Root Location</filename> + field is the Build Directory. + See the "<ulink url='&YOCTO_DOCS_ADT_URL;#using-the-toolchain-from-within-the-build-tree'>Using + BitBake and the Build Directory</ulink>" section in the Yocto Project Application + Developer's Guide for information on how to install the toolchain into the build +directory.</para></listitem> + <listitem><para><emphasis>Specify the Sysroot Location:</emphasis> + This location is where the root filesystem for the target hardware resides. + If you used the ADT Installer, then the location is + <filename>/opt/poky/<release></filename>. + Additionally, when you use the ADT Installer, the same location is used for + the QEMU user-space tools and the NFS boot process.</para> + <para>If you used either of the other two methods to install the toolchain, then the + location of the sysroot filesystem depends on where you separately + extracted and intalled the filesystem.</para> + <para>For information on how to install the toolchain and on how to extract + and install the sysroot filesystem, see the + "<ulink url='&YOCTO_DOCS_ADT_URL;#installing-the-adt'>Installing the ADT and Toolchains</ulink>" section. + </para></listitem> + <listitem><para><emphasis>Select the Target Architecture:</emphasis> + The target architecture is the type of hardware you are + going to use or emulate. + Use the pull-down <filename>Target Architecture</filename> menu to make + your selection. + The pull-down menu should have the supported architectures. + If the architecture you need is not listed in the menu, you + will need to build the image. + See the "<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>" section + of the Yocto Project Quick Start for more information.</para></listitem> + </itemizedlist> + </para> + </section> + + <section id='configuring-the-target-options'> + <title>Configuring the Target Options</title> + + <para> + You can choose to emulate hardware using the QEMU emulator, or you + can choose to run your image on actual hardware. + <itemizedlist> + <listitem><para><emphasis><filename>QEMU:</filename></emphasis> Select this option if + you will be using the QEMU emulator. + If you are using the emulator, you also need to locate the kernel + and specify any custom options.</para> + <para>If you selected <filename>Build system derived toolchain</filename>, + the target kernel you built will be located in the + Build Directory in <filename>tmp/deploy/images</filename> directory. + If you selected <filename>Standalone pre-built toolchain</filename>, the + pre-built image you downloaded is located + in the directory you specified when you downloaded the image.</para> + <para>Most custom options are for advanced QEMU users to further + customize their QEMU instance. + These options are specified between paired angled brackets. + Some options must be specified outside the brackets. + In particular, the options <filename>serial</filename>, + <filename>nographic</filename>, and <filename>kvm</filename> must all + be outside the brackets. + Use the <filename>man qemu</filename> command to get help on all the options + and their use. + The following is an example: + <literallayout class='monospaced'> + serial ‘<-m 256 -full-screen>’ + </literallayout></para> + <para> + Regardless of the mode, Sysroot is already defined as part of the + Cross Compiler Options configuration in the + <filename>Sysroot Location:</filename> field.</para></listitem> + <listitem><para><emphasis><filename>External HW:</filename></emphasis> Select this option + if you will be using actual hardware.</para></listitem> + </itemizedlist> + </para> + + <para> + Click the <filename>OK</filename> button to save your plug-in configurations. + </para> + </section> + </section> + </section> + + <section id='creating-the-project'> + <title>Creating the Project</title> + + <para> + You can create two types of projects: Autotools-based, or Makefile-based. + This section describes how to create Autotools-based projects from within + the Eclipse IDE. + For information on creating Makefile-based projects in a terminal window, see the section + "<ulink url='&YOCTO_DOCS_ADT_URL;#using-the-command-line'>Using the Command Line</ulink>" + in the Yocto Project Application Developer's Guide. + </para> + + <para> + To create a project based on a Yocto template and then display the source code, + follow these steps: + <orderedlist> + <listitem><para>Select <filename>File -> New -> Project</filename>.</para></listitem> + <listitem><para>Double click <filename>CC++</filename>.</para></listitem> + <listitem><para>Double click <filename>C Project</filename> to create the project.</para></listitem> + <listitem><para>Expand <filename>Yocto Project ADT Project</filename>.</para></listitem> + <listitem><para>Select <filename>Hello World ANSI C Autotools Project</filename>. + This is an Autotools-based project based on a Yocto template.</para></listitem> + <listitem><para>Put a name in the <filename>Project name:</filename> field. + Do not use hyphens as part of the name.</para></listitem> + <listitem><para>Click <filename>Next</filename>.</para></listitem> + <listitem><para>Add information in the <filename>Author</filename> and + <filename>Copyright notice</filename> fields.</para></listitem> + <listitem><para>Be sure the <filename>License</filename> field is correct.</para></listitem> + <listitem><para>Click <filename>Finish</filename>.</para></listitem> + <listitem><para>If the "open perspective" prompt appears, click "Yes" so that you + in the C/C++ perspective.</para></listitem> + <listitem><para>The left-hand navigation pane shows your project. + You can display your source by double clicking the project's source file. + </para></listitem> + </orderedlist> + </para> + </section> + + <section id='configuring-the-cross-toolchains'> + <title>Configuring the Cross-Toolchains</title> + + <para> + The earlier section, "<link linkend='configuring-the-eclipse-yocto-plug-in'>Configuring + the Eclipse Yocto Plug-in</link>", sets up the default project + configurations. + You can override these settings for a given project by following these steps: + <orderedlist> + <listitem><para>Select <filename>Project -> Change Yocto Project Settings</filename>: + This selection brings up the <filename>Yocot Project Settings</filename> Dialog + and allows you to make changes specific to an individual project. + </para> + <para>By default, the Cross Compiler Options and Target Options for a project + are inherited from settings you provide using the <filename>Preferences</filename> + Dialog as described earlier + in the "<link linkend='configuring-the-eclipse-yocto-plug-in'>Configuring the Eclipse + Yocto Plug-in</link>" section. + The <filename>Yocto Project Settings</filename> + Dialog allows you to override those default settings + for a given project.</para></listitem> + <listitem><para>Make your configurations for the project and click "OK". + If you are running the Juno version of Eclipse, you can skip down to the next + section where you build the project. + If you are not working with Juno, you need to reconfigure the project as + described in the next step.</para></listitem> + <listitem><para>Select <filename>Project -> Reconfigure Project</filename>: + This selection reconfigures the project by running + <filename>autogen.sh</filename> in the workspace for your project. + The script also runs <filename>libtoolize</filename>, <filename>aclocal</filename>, + <filename>autoconf</filename>, <filename>autoheader</filename>, + <filename>automake --a</filename>, and + <filename>./configure</filename>. + Click on the <filename>Console</filename> tab beneath your source code to + see the results of reconfiguring your project.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='building-the-project'> + <title>Building the Project</title> + + <para> + To build the project in Juno, right click on the project in the navigator pane and select + <filename>Build Project</filename>. + If you are not running Juno, select <filename>Project -> Build Project</filename>. + The console should update and you can note the cross-compiler you are using. + </para> + </section> + + <section id='starting-qemu-in-user-space-nfs-mode'> + <title>Starting QEMU in User Space NFS Mode</title> + + <para> + To start the QEMU emulator from within Eclipse, follow these steps: + <orderedlist> + <listitem><para>Expose the <filename>Run -> External Tools</filename> menu. + Your image should appear as a selectable menu item. + </para></listitem> + <listitem><para>Select your image from the menu to launch the + emulator in a new window.</para></listitem> + <listitem><para>If needed, enter your host root password in the shell window at the prompt. + This sets up a <filename>Tap 0</filename> connection needed for running in user-space + NFS mode.</para></listitem> + <listitem><para>Wait for QEMU to launch.</para></listitem> + <listitem><para>Once QEMU launches, you can begin operating within that + environment. + For example, you could determine the IP Address + for the user-space NFS by using the <filename>ifconfig</filename> command. + </para></listitem> + </orderedlist> + </para> + </section> + + <section id='deploying-and-debugging-the-application'> + <title>Deploying and Debugging the Application</title> + + <para> + Once the QEMU emulator is running the image, using the Eclipse IDE + you can deploy your application and use the emulator to perform debugging. + Follow these steps to deploy the application. + <orderedlist> + <listitem><para>Select <filename>Run -> Debug Configurations...</filename></para></listitem> + <listitem><para>In the left area, expand <filename>C/C++Remote Application</filename>.</para></listitem> + <listitem><para>Locate your project and select it to bring up a new + tabbed view in the <filename>Debug Configurations</filename> Dialog.</para></listitem> + <listitem><para>Enter the absolute path into which you want to deploy + the application. + Use the <filename>Remote Absolute File Path for C/C++Application:</filename> field. + For example, enter <filename>/usr/bin/<programname></filename>.</para></listitem> + <listitem><para>Click on the <filename>Debugger</filename> tab to see the cross-tool debugger + you are using.</para></listitem> + <listitem><para>Click on the <filename>Main</filename> tab.</para></listitem> + <listitem><para>Create a new connection to the QEMU instance + by clicking on <filename>new</filename>.</para></listitem> + <listitem><para>Select <filename>TCF</filename>, which means Target Communication + Framework.</para></listitem> + <listitem><para>Click <filename>Next</filename>.</para></listitem> + <listitem><para>Clear out the <filename>host name</filename> field and enter the IP Address + determined earlier.</para></listitem> + <listitem><para>Click <filename>Finish</filename> to close the + <filename>New Connections</filename> Dialog.</para></listitem> + <listitem><para>Use the drop-down menu now in the <filename>Connection</filename> field and pick + the IP Address you entered.</para></listitem> + <listitem><para>Click <filename>Run</filename> to bring up a login screen + and login.</para></listitem> + <listitem><para>Accept the debug perspective.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='running-user-space-tools'> + <title>Running User-Space Tools</title> + + <para> + As mentioned earlier in the manual, several tools exist that enhance + your development experience. + These tools are aids in developing and debugging applications and images. + You can run these user-space tools from within the Eclipse IDE through the + <filename>YoctoTools</filename> menu. + </para> + + <para> + Once you pick a tool, you need to configure it for the remote target. + Every tool needs to have the connection configured. + You must select an existing TCF-based RSE connection to the remote target. + If one does not exist, click <filename>New</filename> to create one. + </para> + + <para> + Here are some specifics about the remote tools: + <itemizedlist> + <listitem><para><emphasis><filename>OProfile</filename>:</emphasis> Selecting this tool causes + the <filename>oprofile-server</filename> on the remote target to launch on + the local host machine. + The <filename>oprofile-viewer</filename> must be installed on the local host machine and the + <filename>oprofile-server</filename> must be installed on the remote target, + respectively, in order to use. + You must compile and install the <filename>oprofile-viewer</filename> from the source code + on your local host machine. + Furthermore, in order to convert the target's sample format data into a form that the + host can use, you must have <filename>oprofile</filename> version 0.9.4 or + greater installed on the host.</para> + <para>You can locate both the viewer and server from + <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/oprofileui/'></ulink>. + <note>The <filename>oprofile-server</filename> is installed by default on + the <filename>core-image-sato-sdk</filename> image.</note></para></listitem> + <listitem><para><emphasis><filename>Lttng2.0 ust trace import</filename>:</emphasis> + Selecting this tool transfers the remote target's + <filename>Lttng</filename> tracing data back to the local host machine + and uses the <filename>Lttng</filename> Eclipse plug-in to graphically + display the output. + For information on how to use <filename>Lttng</filename> to trace an application, + see <ulink url='http://lttng.org/documentation'></ulink>. + <note>Do not use <filename>Lttng-user space (legacy)</filename> tool. + This tool no longer has any upstream support.</note> + </para> + <para>Before you use the <filename>Lttng2.0 ust trace import</filename> tool, + you need to setup the <filename>Lttng</filename> Eclipse plug-in and create a + <filename>Tracing</filename> project. + Do the following: + <orderedlist> + <listitem><para>Select <filename>Window -> Open Perspective -> Other</filename> + and then select <filename>Tracing</filename>.</para></listitem> + <listitem><para>Click <filename>OK</filename> to change the Eclipse perspective + into the <filename>Tracing</filename> perspective.</para></listitem> + <listitem><para>Create a new <filename>Tracing</filename> project by selecting + <filename>File -> New -> Project</filename>.</para></listitem> + <listitem><para>Choose <filename>Tracing -> Tracing Project</filename>. + </para></listitem> + <listitem><para>Generate your tracing data on the remote target. + </para></listitem> + <listitem><para>Click + <filename>Yocto Project Tools -> Lttng2.0 ust trace import</filename> + to start the data import process.</para></listitem> + <listitem><para>Specify your remote connection name.</para></listitem> + <listitem><para>For the Ust directory path, specify the location of + your remote tracing data. + Make sure the location ends with <filename>ust</filename> (e.g. + <filename>/usr/mysession/ust</filename>.</para></listitem> + <listitem><para>Click <filename>OK</filename> to complete the import process. + The data is now in the local tracing project you created.</para></listitem> + <listitem><para>Right click on the data and then use the menu to + <filename>Select Trace Type... -> Common Trace Format -> Generic CTF Trace</filename> + to map the tracing type.</para></listitem> + <listitem><para>Right click the mouse and select <filename>Open</filename> + to bring up the Eclipse <filename>Lttng</filename> Trace Viewer so you + view the tracing data.</para></listitem> + </orderedlist></para></listitem> + <listitem><para><emphasis><filename>PowerTOP</filename>:</emphasis> Selecting this tool runs + <filename>powertop</filename> on the remote target machine and displays the results in a + new view called <filename>powertop</filename>.</para> + <para><filename>Time to gather data(sec):</filename> is the time passed in seconds before data + is gathered from the remote target for analysis.</para> + <para><filename>show pids in wakeups list:</filename> corresponds to the + <filename>-p</filename> argument + passed to <filename>powertop</filename>.</para></listitem> + <listitem><para><emphasis><filename>LatencyTOP and Perf</filename>:</emphasis> + <filename>latencytop</filename> identifies system latency, while + <filename>perf</filename> monitors the system's + performance counter registers. + Selecting either of these tools causes an RSE terminal view to appear + from which you can run the tools. + Both tools refresh the entire screen to display results while they run.</para></listitem> + </itemizedlist> + </para> + </section> + + <section id='customizing-an-image-using-a-bitbake-commander-project-and-hob'> + <title>Customizing an Image Using a BitBake Commander Project and Hob</title> + + <para> + Within Eclipse, you can create a Yocto BitBake Commander project, + edit the metadata, and then use the + <ulink url='&YOCTO_HOME_URL;/projects/hob'>Hob</ulink> to build a customized + image all within one IDE. + </para> + + <section id='creating-the-yocto-bitbake-commander-project'> + <title>Creating the Yocto BitBake Commander Project</title> + + <para> + To create a Yocto BitBake Commander project, follow these steps: + <orderedlist> + <listitem><para>Select <filename>Window -> Open Perspective -> Other</filename> + and then choose <filename>Bitbake Commander</filename>.</para></listitem> + <listitem><para>Click <filename>OK</filename> to change the Eclipse perspective into the + Bitbake Commander perspective.</para></listitem> + <listitem><para>Select <filename>File -> New -> Project</filename> to create a new Yocto + Bitbake Commander project.</para></listitem> + <listitem><para>Choose <filename>Yocto Project Bitbake Commander -> New Yocto Project</filename> + and click <filename>Next</filename>.</para></listitem> + <listitem><para>Enter the Project Name and choose the Project Location. + The Yocto project's metadata files will be put under the directory + <filename><project_location>/<project_name></filename>. + If that directory does not exist, you need to check + the "Clone from Yocto Git Repository" box, which would execute a + <filename>git clone</filename> command to get the project's metadata files. + </para></listitem> + <listitem><para>Select <filename>Finish</filename> to create the project.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='editing-the-metadata-files'> + <title>Editing the Metadata Files</title> + + <para> + After you create the Yocto Bitbake Commander project, you can modify the metadata files + by opening them in the project. + When editing recipe files (<filename>.bb</filename> files), you can view BitBake + variable values and information by hovering the mouse pointer over the variable name and + waiting a few seconds. + </para> + + <para> + To edit the metadata, follow these steps: + <orderedlist> + <listitem><para>Select your Yocto Bitbake Commander project.</para></listitem> + <listitem><para>Select <filename>File -> New -> Yocto BitBake Commander -> BitBake Recipe</filename> + to open a new recipe wizard.</para></listitem> + <listitem><para>Point to your source by filling in the "SRC_URL" field. + For example, you can add a recipe to your + <link linkend='source-directory'>Source Directory</link> + by defining "SRC_URL" as follows: + <literallayout class='monospaced'> + ftp://ftp.gnu.org/gnu/m4/m4-1.4.9.tar.gz + </literallayout></para></listitem> + <listitem><para>Click "Populate" to calculate the archive md5, sha256, + license checksum values and to auto-generate the recipe filename.</para></listitem> + <listitem><para>Fill in the "Description" field.</para></listitem> + <listitem><para>Be sure values for all required fields exist.</para></listitem> + <listitem><para>Click <filename>Finish</filename>.</para></listitem> + </orderedlist> + </para> + </section> + + <section id='buiding-and-customizing-the-image'> + <title>Building and Customizing the Image</title> + + <para> + To build and customize the image in Eclipse, follow these steps: + <orderedlist> + <listitem><para>Select your Yocto Bitbake Commander project.</para></listitem> + <listitem><para>Select <filename>Project -> Launch HOB</filename>.</para></listitem> + <listitem><para>Enter the Build Directory where you want to put your final images.</para></listitem> + <listitem><para>Click <filename>OK</filename> to launch Hob.</para></listitem> + <listitem><para>Use Hob to customize and build your own images. + For information on Hob, see the + <ulink url='&YOCTO_HOME_URL;/projects/hob'>Hob Project Page</ulink> on the + Yocto Project website.</para></listitem> + </orderedlist> + </para> + </section> + </section> + </section> + + <section id='workflow-using-stand-alone-cross-development-toolchains'> + <title>Workflow Using Stand-alone Cross-development Toolchains</title> + + <para> + If you want to develop an application without prior installation of the ADT, you + still can employ the cross-development toolchain, the QEMU emulator, and a number of supported + target image files. + You just need to follow these general steps: + <orderedlist> + <listitem><para><emphasis>Install the cross-development toolchain for your target hardware:</emphasis> + For information on how to install the toolchain, see the + "<ulink url='&YOCTO_DOCS_ADT_URL;#using-an-existing-toolchain-tarball'>Using a Cross-Toolchain Tarball</ulink>" + section + in the Yocto Project Application Developer's Guide.</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, etc. + 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 + "<ulink url='&YOCTO_DOCS_ADT_URL;#extracting-the-root-filesystem'>Extracting the Root Filesystem</ulink>" + 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://www.qemu.org'>QEMU Home Page</ulink> to download and learn about the + emulator.</para></listitem> + </orderedlist> + </para> + </section> +</section> + +<section id="modifying-temporary-source-code"> + <title>Modifying Temporary Source Code</title> + + <para> + You might + find it helpful during development to modify the temporary source code used by recipes + to build packages. + For example, suppose you are developing a patch and you need to experiment a bit + to figure out your solution. + After you have initially built the package, you can iteratively tweak the + source code, which is located in the + <link linkend='build-directory'>Build Directory</link>, and then + you can force a re-compile and quickly test your altered code. + Once you settle on a solution, you can then preserve your changes in the form of + patches. + You can accomplish these steps all within either a + <ulink url='http://savannah.nongnu.org/projects/quilt'>Quilt</ulink> or + <link linkend='git'>Git</link> workflow. + </para> + + <section id='finding-the-temporary-source-code'> + <title>Finding the Temporary Source Code</title> + + <para> + During a build, the unpacked temporary source code used by recipes + to build packages is available in the Build Directory as + defined by the + <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename> variable. + Below is the default value for the <filename>S</filename> variable as defined in the + <filename>meta/conf/bitbake.conf</filename> configuration file in the + <link linkend='source-directory'>Source Directory</link>: + <literallayout class='monospaced'> + S = ${WORKDIR}/${BP} + </literallayout> + You should be aware that many recipes override the <filename>S</filename> variable. + For example, recipes that fetch their source from Git usually set + <filename>S</filename> to <filename>${WORKDIR}/git</filename>. + <note> + The + <ulink url='&YOCTO_DOCS_REF_URL;#var-BP'><filename>BP</filename></ulink> + represents the base recipe name, which consists of the name and version: + <literallayout class='monospaced'> + BP = ${BPN}-${PV} + </literallayout> + </note> + </para> + + <para> + The path to the work directory for the recipe + (<ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>) depends + on the recipe name and the architecture of the target device. + For example, here is the work directory for recipes and resulting packages that are + not device-dependent: + <literallayout class='monospaced'> + ${TMPDIR}/work/${PACKAGE_ARCH}-poky-${TARGET_OS}/${PN}-${PV}-${PR} + </literallayout> + Let's look at an example without variables. + Assuming a top-level <link linkend='source-directory'>Source Directory</link> + named <filename>poky</filename> + and a default Build Directory of <filename>poky/build</filename>, + the following is the work directory for the <filename>acl</filename> recipe that + creates the <filename>acl</filename> package: + <literallayout class='monospaced'> + ~/poky/build/tmp/work/i586-poky-linux/acl-2.2.51-r3 + </literallayout> + </para> + + <para> + If your resulting package is dependent on the target device, + the work directory varies slightly: + <literallayout class='monospaced'> + ${TMPDIR}/work/${MACHINE}-poky-${TARGET_OS}/${PN}-${PV}-${PR} + </literallayout> + Again, assuming top-level Source Directory named <filename>poky</filename> + and a default Build Directory of <filename>poky/build</filename>, the + following are the work and temporary source directories, respectively, + for the <filename>acl</filename> package that is being + built for a MIPS-based device: + <literallayout class='monospaced'> + ~/poky/build/tmp/work/mips-poky-linux/acl-2.2.51-r2 + ~/poky/build/tmp/work/mips-poky-linux/acl-2.2.51-r2/acl-2.2.51 + </literallayout> + </para> + + <note> + To better understand how the OpenEmbedded build system resolves directories during the + build process, see the glossary entries for the + <ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-TOPDIR'><filename>TOPDIR</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ARCH'><filename>PACKAGE_ARCH</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-TARGET_OS'><filename>TARGET_OS</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>, + <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>, + and + <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink> + variables in the Yocto Project Reference Manual. + </note> + + <para> + Now that you know where to locate the directory that has the temporary source code, + you can use a Quilt or Git workflow to make your edits, test the changes, + and preserve the changes in the form of patches. + </para> + </section> + + <section id="using-a-quilt-workflow"> + <title>Using a Quilt Workflow</title> + + <para> + <ulink url='http://savannah.nongnu.org/projects/quilt'>Quilt</ulink> + is a powerful tool that allows you to capture source code changes without having + a clean source tree. + This section outlines the typical workflow you can use to modify temporary source code, + test changes, and then preserve the changes in the form of a patch all using Quilt. + </para> + + <para> + Follow these general steps: + <orderedlist> + <listitem><para><emphasis>Find the Source Code:</emphasis> + The temporary source code used by the OpenEmbedded build system is kept in the + Build Directory. + See the + "<link linkend='finding-the-temporary-source-code'>Finding the Temporary Source Code</link>" + section to learn how to locate the directory that has the temporary source code for a + particular package.</para></listitem> + <listitem><para><emphasis>Change Your Working Directory:</emphasis> + You need to be in the directory that has the temporary source code. + That directory is defined by the + <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink> + variable.</para></listitem> + <listitem><para><emphasis>Create a New Patch:</emphasis> + Before modifying source code, you need to create a new patch. + To create a new patch file, use <filename>quilt new</filename> as below: + <literallayout class='monospaced'> + $ quilt new my_changes.patch + </literallayout></para></listitem> + <listitem><para><emphasis>Notify Quilt and Add Files:</emphasis> + After creating the patch, you need to notify Quilt about the files + you plan to edit. + You notify Quilt by adding the files to the patch you just created: + <literallayout class='monospaced'> + $ quilt add file1.c file2.c file3.c + </literallayout> + </para></listitem> + <listitem><para><emphasis>Edit the Files:</emphasis> + Make your changes in the temporary source code to the files you added + to the patch.</para></listitem> + <listitem><para><emphasis>Test Your Changes:</emphasis> + Once you have modified the source code, the easiest way to test your changes + is by calling the <filename>compile</filename> task as shown in the following example: + <literallayout class='monospaced'> + $ bitbake -c compile -f <name_of_package> + </literallayout> + The <filename>-f</filename> or <filename>--force</filename> + option forces re-execution of the specified task. + If you find problems with your code, you can just keep editing and + re-testing iteratively until things work as expected. + <note>All the modifications you make to the temporary source code + disappear once you <filename>-c clean</filename> or + <filename>-c cleanall</filename> with BitBake for the package. + Modifications will also disappear if you use the <filename>rm_work</filename> + feature as described in the + "<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>" + section of the Yocto Project Quick Start. + </note></para></listitem> + <listitem><para><emphasis>Generate the Patch:</emphasis> + Once your changes work as expected, you need to use Quilt to generate the final patch that + contains all your modifications. + <literallayout class='monospaced'> + $ quilt refresh + </literallayout> + At this point the <filename>my_changes.patch</filename> file has all your edits made + to the <filename>file1.c</filename>, <filename>file2.c</filename>, and + <filename>file3.c</filename> files.</para> + <para>You can find the resulting patch file in the <filename>patches/</filename> + subdirectory of the source (<filename>S</filename>) directory.</para></listitem> + <listitem><para><emphasis>Copy the Patch File:</emphasis> + For simplicity, copy the patch file into a directory named <filename>files</filename>, + which you can create in the same directory that holds the recipe + (<filename>.bb</filename>) file or the + append (<filename>.bbappend</filename>) file. + Placing the patch here guarantees that the OpenEmbedded build system will find + the patch. + Next, add the patch into the + <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename> + of the recipe. + Here is an example: + <literallayout class='monospaced'> + SRC_URI += "file://my_changes.patch" + </literallayout></para></listitem> + <listitem><para><emphasis>Increment the Recipe Revision Number:</emphasis> + Finally, don't forget to 'bump' the + <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PR'>PR</ulink></filename> + value in the recipe since the resulting packages have changed.</para></listitem> + </orderedlist> + </para> </section> + + <section id='using-a-git-workflow'> + <title>Using a Git Workflow</title> + <para> + Git is an even more powerful tool that allows you to capture source code changes without having + a clean source tree. + This section outlines the typical workflow you can use to modify temporary source code, + test changes, and then preserve the changes in the form of a patch all using Git. + For general information on Git as it is used in the Yocto Project, see the + "<link linkend='git'>Git</link>" section. + </para> + + <note> + This workflow uses Git only for its ability to manage local changes to the source code + and produce patches independent of any version control system used with the Yocto Project. + </note> + + <para> + Follow these general steps: + <orderedlist> + <listitem><para><emphasis>Find the Source Code:</emphasis> + The temporary source code used by the OpenEmbedded build system is kept in the + Build Directory. + See the + "<link linkend='finding-the-temporary-source-code'>Finding the Temporary Source Code</link>" + section to learn how to locate the directory that has the temporary source code for a + particular package.</para></listitem> + <listitem><para><emphasis>Change Your Working Directory:</emphasis> + You need to be in the directory that has the temporary source code. + That directory is defined by the + <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink> + variable.</para></listitem> + <listitem><para><emphasis>If needed, initialize a Git Repository:</emphasis> + If the recipe you are working with does not use a Git fetcher, + you need to set up a Git repository as follows: + <literallayout class='monospaced'> + $ git init + $ git add * + $ git commit -m "initial revision" + </literallayout> + The above Git commands initialize a Git repository that is based on the + files in your current working directory, stage all the files, and commit + the files. + At this point, your Git repository is aware of all the source code files. + Any edits you now make to files can be committed later and will be tracked by + Git.</para></listitem> + <listitem><para><emphasis>Edit the Files:</emphasis> + Make your changes to the temporary source code.</para></listitem> + <listitem><para><emphasis>Test Your Changes:</emphasis> + Once you have modified the source code, the easiest way to test your changes + is by calling the <filename>compile</filename> task as shown in the following example: + <literallayout class='monospaced'> + $ bitbake -c compile -f <name_of_package> + </literallayout> + The <filename>-f</filename> or <filename>--force</filename> + option forces re-execution of the specified task. + If you find problems with your code, you can just keep editing and + re-testing iteratively until things work as expected. + <note>All the modifications you make to the temporary source code + disappear once you <filename>-c clean</filename>, <filename>-c cleansstate</filename>, + or <filename>-c cleanall</filename> with BitBake for the package. + Modifications will also disappear if you use the <filename>rm_work</filename> + feature as described in the + "<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>" + section of the Yocto Project Quick Start. + </note></para></listitem> + <listitem><para><emphasis>See the List of Files You Changed:</emphasis> + Use the <filename>git status</filename> command to see what files you have actually edited. + The ability to have Git track the files you have changed is an advantage that this + workflow has over the Quilt workflow. + Here is the Git command to list your changed files: + <literallayout class='monospaced'> + $ git status + </literallayout></para></listitem> + <listitem><para><emphasis>Stage the Modified Files:</emphasis> + Use the <filename>git add</filename> command to stage the changed files so they + can be committed as follows: + <literallayout class='monospaced'> + $ git add file1.c file2.c file3.c + </literallayout></para></listitem> + <listitem><para><emphasis>Commit the Staged Files and View Your Changes:</emphasis> + Use the <filename>git commit</filename> command to commit the changes to the + local repository. + Once you have committed the files, you can use the <filename>git log</filename> + command to see your changes: + <literallayout class='monospaced'> + $ git commit -m "<commit-summary-message>" + $ git log + </literallayout> + <note>The name of the patch file created in the next step is based on your + <filename>commit-summary-message</filename>.</note></para></listitem> + <listitem><para><emphasis>Generate the Patch:</emphasis> + Once the changes are committed, use the <filename>git format-patch</filename> + command to generate a patch file: + <literallayout class='monospaced'> + $ git format-patch -1 + </literallayout> + Specifying "-1" causes Git to generate the + patch file for the most recent commit.</para> + <para>At this point, the patch file has all your edits made + to the <filename>file1.c</filename>, <filename>file2.c</filename>, and + <filename>file3.c</filename> files. + You can find the resulting patch file in the current directory and it + is named according to the <filename>git commit</filename> summary line. + The patch file ends with <filename>.patch</filename>.</para></listitem> + <listitem><para><emphasis>Copy the Patch File:</emphasis> + For simplicity, copy the patch file into a directory named <filename>files</filename>, + which you can create in the same directory that holds the recipe + (<filename>.bb</filename>) file or the + append (<filename>.bbappend</filename>) file. + Placing the patch here guarantees that the OpenEmbedded build system will find + the patch. + Next, add the patch into the + <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename> + of the recipe. + Here is an example: + <literallayout class='monospaced'> + SRC_URI += "file://0001-<commit-summary-message>.patch" + </literallayout></para></listitem> + <listitem><para><emphasis>Increment the Recipe Revision Number:</emphasis> + Finally, don't forget to 'bump' the + <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PR'>PR</ulink></filename> + value in the recipe since the resulting packages have changed.</para></listitem> + </orderedlist> + </para> + </section> +</section> + +<section id='image-development-using-hob'> + <title>Image Development Using Hob</title> + + <para> + The <ulink url='&YOCTO_HOME_URL;/projects/hob'>Hob</ulink> is a graphical user interface for the + OpenEmbedded build system, which is based on BitBake. + You can use the Hob to build custom operating system images within the Yocto Project build environment. + Hob simply provides a friendly interface over the build system used during system development. + In other words, building images with the Hob lets you take care of common build tasks more easily. + </para> + + <para> + For a better understanding of Hob, see the project page at + <ulink url='&YOCTO_HOME_URL;/projects/hob'></ulink> on the Yocto Project website. + The page has a short introductory training video on Hob. + The following lists some features of Hob: + <itemizedlist> + <listitem><para>You can setup and run Hob using these commands: + <literallayout class='monospaced'> + $ source oe-init-build-env + $ hob + </literallayout></para></listitem> + <listitem><para>You can set the + <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink> + for which you are building the image.</para></listitem> + <listitem><para>You can modify various policy settings such as the package format used to build with, + the parrallelism BitBake uses, whether or not to build an external toolchain, and which host + to build against.</para></listitem> + <listitem><para>You can manage + <link linkend='understanding-and-creating-layers'>layers</link>.</para></listitem> + <listitem><para>You can select a base image and then add extra packages for your custom build. + </para></listitem> + <listitem><para>You can launch and monitor the build from within Hob.</para></listitem> + </itemizedlist> + </para> +</section> + +<section id="platdev-appdev-devshell"> + <title>Using a Development Shell</title> + + <para> + When debugging certain commands or even when just editing packages, + <filename>devshell</filename> can be a useful tool. + When you invoke <filename>devshell</filename>, source files are + extracted into your working directory and patches are applied. + Then, a new terminal is opened and you are placed in the working directory. + In the new terminal, all the OpenEmbedded build-related environment variables are + still defined so you can use commands such as <filename>configure</filename> and + <filename>make</filename>. + The commands execute just as if the OpenEmbedded build system were executing them. + Consequently, working this way can be helpful when debugging a build or preparing + software to be used with the OpenEmbedded build system. + </para> + + <para> + Following is an example that uses <filename>devshell</filename> on a target named + <filename>matchbox-desktop</filename>: + <literallayout class='monospaced'> + $ bitbake matchbox-desktop -c devshell + </literallayout> + </para> + + <para> + This command spawns a terminal with a shell prompt within the OpenEmbedded build environment. + The <ulink url='&YOCTO_DOCS_REF_URL;#var-OE_TERMINAL'><filename>OE_TERMINAL</filename></ulink> + controls what type of shell is opened. + </para> + + <para> + For spawned terminals, the following occurs: + <itemizedlist> + <listitem><para>The <filename>PATH</filename> variable includes the + cross-toolchain.</para></listitem> + <listitem><para>The <filename>pkgconfig</filename> variables find the correct + <filename>.pc</filename> files.</para></listitem> + <listitem><para>The <filename>configure</filename> command finds the + Yocto Project site files as well as any other necessary files.</para></listitem> + </itemizedlist> + </para> + + <para> + Within this environment, you can run configure or compile + commands as if they were being run by + the OpenEmbedded build system itself. + As noted earlier, the working directory also automatically changes to the + Source Directory (<ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>). + </para> + + <para> + When you are finished, you just exit the shell or close the terminal window. + </para> + + <note> + <para> + It is worth remembering that when using <filename>devshell</filename> + you need to use the full compiler name such as <filename>arm-poky-linux-gnueabi-gcc</filename> + instead of just using <filename>gcc</filename>. + The same applies to other applications such as <filename>binutils</filename>, + <filename>libtool</filename> and so forth. + BitBake sets up environment variables such as <filename>CC</filename> + to assist applications, such as <filename>make</filename> to find the correct tools. + </para> + + <para> + It is also worth noting that <filename>devshell</filename> still works over + X11 forwarding and similar situations + </para> + </note> +</section> + +</chapter> +<!-- 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