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authorScott Rifenbark <scott.m.rifenbark@intel.com>2011-07-27 12:10:25 -0700
committerRichard Purdie <richard.purdie@linuxfoundation.org>2011-08-04 15:06:47 +0100
commit3aef350c390a270a410673435de63ee5d21d117b (patch)
tree54a662f8d46b1aa0a75f2e6bc764d10f24db6b6d /documentation
parent6d7c8f6398813bb527c102344cb3a5009d334af1 (diff)
downloadast2050-yocto-poky-3aef350c390a270a410673435de63ee5d21d117b.zip
ast2050-yocto-poky-3aef350c390a270a410673435de63ee5d21d117b.tar.gz
documentation/dev-manual/dev-manual-model.xml: Moved BSP dev summary here
The "models" chapter is going to be the overview section for the cases. Thus, the cases chapter will disappear. This is a first step in that direction. (From yocto-docs rev: fe3985db8e1dbc7bff6565d3624bccac0f809621) Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation')
-rw-r--r--documentation/dev-manual/dev-manual-model.xml189
1 files changed, 182 insertions, 7 deletions
diff --git a/documentation/dev-manual/dev-manual-model.xml b/documentation/dev-manual/dev-manual-model.xml
index bb08762..8d8c2ae 100644
--- a/documentation/dev-manual/dev-manual-model.xml
+++ b/documentation/dev-manual/dev-manual-model.xml
@@ -20,19 +20,194 @@
</para>
<section id='place-holder-section-one'>
- <title>Place-Holder Section One</title>
+ <title>Place-Holder Section for Development in General</title>
<para>
Text needed here.
</para>
-</section>
-<section id='place-holder-section-two'>
- <title>Place-Holder Section Two</title>
+ <section id='developing-a-board-support-package-bsp-model'>
+ <title>Developing a Board Support Package (BSP)</title>
- <para>
- Text needed here.
- </para>
+ <para>
+ A BSP is a package of recipes that when applied while building an image results in
+ an image 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 <xref linkend='yocto-project-terms'>Yocto Project Terms</xref> in this manual.
+ </note>
+
+ <para>
+ The remainder of this section presents the basic steps to create a BSP basing it on an
+ existing BSP that ships with the Yocto Project.
+ You can reference <xref linkend='dev-manual-bsp-appendix'>BSP Development Case</xref>
+ for a detailed example that uses the Crown Bay BSP as a base BSP from which to start.
+ </para>
+
+ <para>
+ Here are the basic steps involved in creating a BSP:
+ <orderedlist>
+ <listitem><para><emphasis>Set up your host development system to support
+ development using the Yocto Project</emphasis>: See
+ <ulink url='http://www.yoctoproject.org/docs/1.1/yocto-project-qs/yocto-project-qs.html#the-linux-distro'>
+ The Linux Distributions</ulink> section and
+ <ulink url='http://www.yoctoproject.org/docs/1.1/yocto-project-qs/yocto-project-qs.html#packages'>
+ The Packages</ulink> section both
+ in the Yocto Project Quick Start for requirements.
+ You will also need a release of Yocto Project installed on the host.</para></listitem>
+ <listitem><para><emphasis>Establish a local copy of the Yocto Project files on your
+ system</emphasis>: You need to have the Yocto Project files available on your host system.
+ Having the Yocto Project files on your system gives you access to the build
+ process and tools you need.
+ For information on how to get these files, see the
+ <xref linkend='getting-setup'>Getting Setup</xref> section in this manual.</para></listitem>
+ <listitem><para><emphasis>Choose a Yocto Project-supported BSP as your base BSP</emphasis>:
+ The Yocto Project ships with several BSPs that support various hardware.
+ It is best to base your new BSP on an existing BSP rather than create all the
+ recipes and configuration files from scratch.
+ While it is possible to create everything from scratch, basing your new BSP
+ on something that is close is much easier.
+ Or, at a minimum, it gives you some structure with which to start.</para>
+ <para>At this point you need to understand your target hardware well enough to determine which
+ existing BSP it most closely matches.
+ Things to consider are your hardware’s on-board features such as CPU type and graphics support.
+ You should look at the README files for supported BSPs to get an idea of which one
+ you could use.
+ A generic Atom-based BSP to consider is the Crown Bay that does not support
+ the Intel® Embedded Media Graphics Driver (EMGD).
+ The remainder of this example uses that base BSP.</para>
+ <para>To see the supported BSPs, go to the Yocto Project
+ <ulink url='http://www.yoctoproject.org/download'>download page</ulink> and click
+ on “BSP Downloads.”</para></listitem>
+ <listitem><para><emphasis>Establish a local copy of the base BSP files</emphasis>: Having
+ the BSP files on your system gives you access to the build
+ process and tools you need.
+ For information on how to get these files, see
+ <xref linkend='getting-setup'>Getting Setup</xref> earlier in this manual.</para></listitem>
+ <listitem><para><emphasis>Create your own BSP layer</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.
+ Consider an application as another example that illustrates a layer.
+ 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 Yocto Project build
+ system knows about.</para>
+ <note>The Yocto Project supports four BSPs 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 local Yocto Project files.
+ Consequently, they are not totally isolated in the spirit of layers unless you think
+ of <filename>meta-yocto</filename> as a layer itself.
+ On the other hand, BSP layers for Crown Bay, Emenlow, Jasper Forest,
+ N450, and Sugar Bay are isolated.</note>
+ <para>When you set up a layer for a new BSP you should follow a standard layout.
+ This layout is described in the
+ <ulink url='http://www.yoctoproject.org/docs/1.1/bsp-guide/bsp-guide.html#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 the Crown Bay BSP in this example by examining the
+ directory structure of the <filename>meta-crownbay</filename> layer inside the
+ local Yocto Project files.</para></listitem>
+ <listitem><para><emphasis>Make configuration and recipe 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> within the
+ BSP layer.</para>
+ <para>Configuration changes identify where your new layer is on the local system
+ and identify which kernel you are going to use.
+ Recipe changes include altering recipes (<filename>.bb</filename> files), removing
+ recipes you don't use, and adding new recipes 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 Yocto Project 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.</para>
+ <para>The entire process for building an image is overviewed in the
+ <ulink url='http://www.yoctoproject.org/docs/1.1/yocto-project-qs/yocto-project-qs.html#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 Yocto Project uses the BitBake
+ tool to build images based on the type of image
+ you want to create.
+ You can find more information on BitBake
+ <ulink url='http://bitbake.berlios.de/manual/'>here</ulink>.</para>
+ <para>The build process supports several types of images to satisfy different needs.
+ When you issue the BitBake command you provide a “top-level” recipe that essentially
+ starts the process off of building the type of image you want.</para>
+ <para>[WRITER'S NOTE: Consider moving this to the Poky Reference Manual.]</para>
+ <para>You can find these recipes in the <filename>meta/recipes-core/images</filename> and
+ <filename>meta/recipes-sato/images</filename> directories of your local Yocto Project
+ file structure (Git repository or extracted release tarball).
+ Although the recipe names are somewhat explanatory, here is a list that describes them:
+ <itemizedlist>
+ <listitem><para><emphasis>Base</emphasis> – A foundational basic image without support
+ for X that can be reasonably used for customization.</para></listitem>
+ <listitem><para><emphasis>Core</emphasis> – A foundational basic image with support for
+ X that can be reasonably used for customization.</para></listitem>
+ <listitem><para><emphasis>Direct Disk</emphasis> – An image that you can copy directory to
+ the disk of the target device.</para></listitem>
+ <listitem><para><emphasis>Live</emphasis> – An image you can run from a USB device or from
+ a CD without having to first install something.</para></listitem>
+ <listitem><para><emphasis>Minimal</emphasis> – A small image without a GUI.
+ This image is not much more than a kernel with a shell.</para></listitem>
+ <listitem><para><emphasis>Minimal Development</emphasis> – A Minimal image suitable for
+ development work.</para></listitem>
+ <listitem><para><emphasis>Minimal Direct Disk</emphasis> – A Minimal Direct
+ Disk image.</para></listitem>
+ <listitem><para><emphasis>Minimal RAM-based Initial Root Filesystem</emphasis> –
+ A minimal image
+ that has the <filename>initramfs</filename> as part of the kernel, which allows the
+ system to find the first “init” program more efficiently.</para></listitem>
+ <listitem><para><emphasis>Minimal Live</emphasis> – A Minimal Live image.</para></listitem>
+ <listitem><para><emphasis>Minimal MTD Utilities</emphasis> – A minimal image that has support
+ for the MTD utilities, which let the user interact with the MTD subsystem in
+ the kernel to perform operations on flash devices.</para></listitem>
+ <listitem><para><emphasis>Sato</emphasis> – An image with Sato support, a mobile environment
+ and visual style that works well with mobile devices.</para></listitem>
+ <listitem><para><emphasis>Sato Development</emphasis> – A Sato image suitable for
+ development work.</para></listitem>
+ <listitem><para><emphasis>Sato Direct Disk</emphasis> – A Sato Direct
+ Disk image.</para></listitem>
+ <listitem><para><emphasis>Sato Live</emphasis> – A Sato Live image.</para></listitem>
+ <listitem><para><emphasis>Sato SDK</emphasis> – A Sato image that includes the Yocto Project
+ toolchain and development libraries.</para></listitem>
+ <listitem><para><emphasis>Sato SDK Direct Disk</emphasis> – A Sato SDK Direct
+ Disk image.</para></listitem>
+ <listitem><para><emphasis>Sato SDK Live</emphasis> – A Sato SDK Live
+ image.</para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ </orderedlist>
+ </para>
+
+ <para>
+ You can view a video presentation of the BSP creation process
+ <ulink url='http://free-electrons.com/blog/elc-2011-videos'>here</ulink>.
+ You can also find supplemental information in the
+ <ulink url='http://yoctoproject.org/docs/1.1/bsp-guide/bsp-guide.html'>
+ Board Support Package (BSP) Development Guide</ulink>.
+ Finally, there is wiki page write up of the example located
+ <ulink url='https://wiki.yoctoproject.org/wiki/Transcript:_creating_one_generic_Atom_BSP_from_another'>
+ here</ulink> you might find helpful.
+ </para>
+ </section>
+
+ <section id='place-holder-section-two'>
+ <title>Place-Holder Section For Application Development</title>
+
+ <para>
+ Text needed here.
+ </para>
+ </section>
</section>
</chapter>
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