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documentation: dev-manual - Removed Appendix A. 

This appendix is antiquated and needed removed.  The BSP
development example is now in the BSP guide where it talks
about running the yocto-bsp script.

(From yocto-docs rev: 892ff450d79a7564a72f11eb7510d349ca71d47a)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2012-10-03 14:19:35 -07:00 committed by Richard Purdie
parent 20a2dda2c2
commit 1f0a3c56ba
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documentation/dev-manual/dev-manual-bsp-appendix.xml
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<!DOCTYPE appendix 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; ] >
<appendix id='dev-manual-bsp-appendix'>
<title>BSP Development Example</title>
<para>
This appendix provides a complete BSP development example.
The example assumes the following:
<itemizedlist>
<listitem><para>No previous preparation or use of the Yocto Project.</para></listitem>
<listitem><para>Use of the Fish River Island 2 Board Support Package (BSP) as a "base" BSP from
which to work.
The example begins with the Fish River Island 2 BSP as the starting point
but ends by building a new 'atom-pc' BSP, which was based on the Fish River Island 2 BSP.
</para></listitem>
<listitem><para>Shell commands assume <filename>bash</filename></para></listitem>
<listitem><para>Example was developed on an Intel-based Core i7 platform running
Ubuntu 10.04 LTS released in April of 2010.</para></listitem>
</itemizedlist>
</para>
<section id='getting-local-yocto-project-files-and-bsp-files'>
<title>Getting Local Source Files and BSP Files</title>
<para>
You need to have the <link linkend='source-directory'>Source Directory</link>
available on your host system.
You can set up this directory through tarball extraction or by cloning the
<filename>poky</filename> Git repository.
The following paragraphs describe both methods.
For additional information, see the bulleted item
"<link linkend='local-yp-release'>Yocto Project Release</link>".
</para>
<para>
As mentioned, one way to set up the Source Directory is to use Git to clone the
<filename>poky</filename> repository.
These commands create a local copy of the Git repository.
By default, the top-level directory of the repository is named <filename>poky</filename>:
<literallayout class='monospaced'>
$ git clone git://git.yoctoproject.org/poky
$ cd poky
</literallayout>
Alternatively, you can start with the downloaded Poky "&DISTRO_NAME;" tarball.
These commands unpack the tarball into a Source Directory structure.
By default, the top-level directory of the Source Directory is named
<filename>&YOCTO_POKY;</filename>:
<literallayout class='monospaced'>
$ tar xfj &YOCTO_POKY_TARBALL;
$ cd &YOCTO_POKY;
</literallayout>
<note><para>If you're using the tarball method, you can ignore all the following steps that
ask you to carry out Git operations.
You already have the results of those operations
in the form of the &DISTRO_NAME; release tarballs.
Consequently, there is nothing left to do other than extract those tarballs into the
proper locations.</para>
<para>Once you expand the released tarball, you have a snapshot of the Git repository
that represents a specific release.
Fundamentally, this is different than having a local copy of the Poky Git repository.
Given the tarball method, changes you make are building on top of a release.
With the Git repository method you have the ability to track development
and keep changes in revision control.
See the
"<link linkend='repositories-tags-and-branches'>Repositories, Tags, and Branches</link>" section
for more discussion around these differences.</para></note>
</para>
<para>
With the local <filename>poky</filename> Git repository set up,
you have all the development branches available to you from which you can work.
Next, you need to be sure that your local repository reflects the exact
release in which you are interested.
From inside the repository you can see the development branches that represent
areas of development that have diverged from the main (master) branch
at some point, such as a branch to track a maintenance release's development.
You can also see the tag names used to mark snapshots of stable releases or
points in the repository.
Use the following commands to list out the branches and the tags in the repository,
respectively.
<literallayout class='monospaced'>
$ git branch -a
$ git tag -l
</literallayout>
For this example, we are going to use the Yocto Project &DISTRO; Release, which is code
named "&DISTRO_NAME;".
To make sure we have a local area (branch in Git terms) on our machine that
reflects the &DISTRO; release, we can use the following commands:
<literallayout class='monospaced'>
$ cd ~/poky
$ git fetch --tags
$ git checkout -b &DISTRO_NAME;-&POKYVERSION; origin/&DISTRO_NAME;
Switched to a new branch '&DISTRO_NAME;-&POKYVERSION;'
</literallayout>
The <filename>git fetch --tags</filename> is somewhat redundant since you just set
up the repository and should have all the tags.
The <filename>fetch</filename> command makes sure all the tags are available in your
local repository.
The Git <filename>checkout</filename> command with the <filename>-b</filename> option
creates a local branch for you named <filename>&DISTRO_NAME;-&POKYVERSION;</filename>.
Your local branch begins in the same state as the Yocto Project &DISTRO; released tarball
marked with the <filename>&DISTRO_NAME;-&POKYVERSION;</filename> tag in the source repositories.
</para>
</section>
<section id='choosing-a-base-bsp-app'>
<title>Choosing a Base BSP</title>
<para>
For this example, the base BSP is the <trademark class='registered'>Intel</trademark>
<trademark class='trade'>Atom</trademark> Processor E660 with Intel Platform
Controller Hub EG20T Development Kit, which is otherwise referred to as "Fish River Island 2."
The BSP layer is <filename>meta-fri2</filename>.
The base BSP is simply the BSP
we will be using as a starting point, so don't worry if you don't actually have Fish River Island 2
hardware.
The remainder of the example transforms the base BSP into a BSP that should be
able to boot on generic atom-pc (netbook) hardware.
</para>
<para>
For information on how to choose a base BSP, see
"<link linkend='developing-a-board-support-package-bsp'>Developing a Board Support Package (BSP)</link>".
</para>
</section>
<section id='getting-your-base-bsp-app'>
<title>Getting Your Base BSP</title>
<para>
You need to have the base BSP layer on your development system.
Similar to the local <link linkend='source-directory'>Source Directory</link>,
you can get the BSP
layer in a couple of different ways:
download the BSP tarball and extract it, or set up a local Git repository that
has the BSP layers.
You should use the same method that you used to set up the Source Directory earlier.
See "<link linkend='getting-setup'>Getting Setup</link>" for information on how to get
the BSP files.
</para>
<para>
This example assumes the BSP layer will be located within a directory named
<filename>meta-intel</filename> contained within the <filename>poky</filename>
parent directory.
The following steps will automatically create the
<filename>meta-intel</filename> directory and the contained
<filename>meta-fri2</filename> starting point in both the Git and the tarball cases.
</para>
<para>
If you're using the Git method, you could do the following to create
the starting layout after you have made sure you are in the <filename>poky</filename>
directory created in the previous steps:
<literallayout class='monospaced'>
$ git clone git://git.yoctoproject.org/meta-intel.git
$ cd meta-intel
</literallayout>
Alternatively, you can start with the downloaded Fish River Island 2 tarball.
You can download the &DISTRO_NAME; version of the BSP tarball from the
<ulink url='&YOCTO_HOME_URL;/download'>Downloads</ulink> page of the
Yocto Project website.
Here is the specific link for the tarball needed for this example:
<ulink url='&YOCTO_MACHINES_DL_URL;/fri2-noemgd/fri2-noemgd-&DISTRO_NAME;-&POKYVERSION;.tar.bz2'></ulink>.
Again, be sure that you are already in the <filename>poky</filename> directory
as described previously before installing the tarball:
<literallayout class='monospaced'>
$ tar xfj fri2-noemgd-&DISTRO_NAME;-&POKYVERSION;.tar.bz2
$ cd meta-intel
</literallayout>
</para>
<para>
The <filename>meta-intel</filename> directory contains all the metadata
that supports BSP creation.
If you're using the Git method, the following
step will switch to the &DISTRO_NAME; metadata.
If you're using the tarball method, you already have the correct metadata and can
skip to the next step.
Because <filename>meta-intel</filename> is its own Git repository, you will want
to be sure you are in the appropriate branch for your work.
For this example we are going to use the <filename>&DISTRO_NAME;</filename>
branch.
<literallayout class='monospaced'>
$ git checkout -b &DISTRO_NAME;-&POKYVERSION; origin/&DISTRO_NAME;
Branch &DISTRO_NAME;-&POKYVERSION; set up to track remote branch &DISTRO_NAME; from origin.
Switched to a new branch '&DISTRO_NAME;-&POKYVERSION;'
</literallayout>
</para>
</section>
<section id='making-a-copy-of-the-base bsp-to-create-your-new-bsp-layer-app'>
<title>Making a Copy of the Base BSP to Create Your New BSP Layer</title>
<para>
Now that you have set up the Source Directory and included the base BSP files, you need to
create a new layer for your BSP.
To create your BSP layer, you simply copy the <filename>meta-fri2</filename>
layer to a new layer.
</para>
<para>
For this example, the new layer will be named <filename>meta-mymachine</filename>.
The name should follow the BSP layer naming convention, which is
<filename>meta-&lt;name&gt;</filename>.
The following assumes your working directory is <filename>meta-intel</filename>
inside your Source Directory.
To start your new layer, just copy the new layer alongside the existing
BSP layers in the <filename>meta-intel</filename> directory:
<literallayout class='monospaced'>
$ cp -a meta-fri2/ meta-mymachine
</literallayout>
</para>
</section>
<section id='making-changes-to-your-bsp-app'>
<title>Making Changes to Your BSP</title>
<para>
Right now you have two identical BSP layers with different names:
<filename>meta-fri2</filename> and <filename>meta-mymachine</filename>.
You need to change your configurations so that they work for your new BSP and
your particular hardware.
The following sections look at each of these areas of the BSP.
</para>
<section id='changing-the-bsp-configuration'>
<title>Changing the BSP Configuration</title>
<para>
We will look first at the configurations, which are all done in the layer’s
<filename>conf</filename> directory.
</para>
<para>
First, since in this example the new BSP will not support EMGD, we will get rid of the
<filename>fri2.conf</filename> file and then rename the
<filename>fri2-noemgd.conf</filename> file to <filename>mymachine.conf</filename>.
Much of what we do in the configuration directory is designed to help the OpenEmbedded
build system work with the new layer and to be able to find and use the right software.
The following two commands result in a single machine configuration file named
<filename>mymachine.conf</filename>.
<literallayout class='monospaced'>
$ rm meta-mymachine/conf/machine/fri2.conf
$ mv meta-mymachine/conf/machine/fri2-noemgd.conf \
meta-mymachine/conf/machine/mymachine.conf
</literallayout>
</para>
<para>
Next, we need to make changes to the <filename>mymachine.conf</filename> itself.
The only changes we want to make for this example are to the comment lines.
Changing comments, of course, is never strictly necessary, but it's always good form to make
them reflect reality as much as possible.
Here, simply substitute the Fish River Island 2 name with an appropriate name for the BSP
(<filename>mymachine</filename> in this case) and change the description to
something that describes your hardware.
</para>
<para>
Note that inside the <filename>mymachine.conf</filename> is the
<filename>PREFERRED_VERSION_linux-yocto</filename> statement.
This statement identifies the kernel that the BSP is going to use.
In this case, the BSP is using <filename>linux-yocto</filename>, which is the
current Yocto Project kernel based on the Linux 3.4 release.
</para>
<para>
The next configuration file in the new BSP layer we need to edit is
<filename>meta-mymachine/conf/layer.conf</filename>.
This file identifies build information needed for the new layer.
You can see the
"<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout-layer'>Layer Configuration File</ulink>" section
in The Board Support Packages (BSP) Development Guide for more information on this configuration file.
Basically, we are changing the existing statements to work with our BSP.
</para>
<para>
The file contains these statements that reference the Fish River Island 2 BSP:
<literallayout class='monospaced'>
BBFILE_COLLECTIONS += "fri2"
BBFILE_PATTERN_fri2 := "^${LAYERDIR}/"
BBFILE_PRIORITY_fri2 = "6"
LAYERDEPENDS_fri2 = "intel"
</literallayout>
</para>
<para>
Simply substitute the machine string name <filename>fri2</filename>
with the new machine name <filename>mymachine</filename> to get the following:
<literallayout class='monospaced'>
BBFILE_COLLECTIONS += "mymachine"
BBFILE_PATTERN_mymachine := "^${LAYERDIR}/"
BBFILE_PRIORITY_mymachine = "6"
LAYERDEPENDS_mymachine = "intel"
</literallayout>
</para>
</section>
<section id='changing-the-recipes-in-your-bsp'>
<title>Changing the Recipes in Your BSP</title>
<para>
Now we will take a look at the recipes in your new layer.
The standard BSP structure has areas for BSP, graphics, core, and kernel recipes.
When you create a BSP, you use these areas for appropriate recipes and append files.
Recipes take the form of <filename>.bb</filename> files, while append files take
the form of <filename>.bbappend</filename> files.
If you want to leverage the existing recipes the OpenEmbedded build system uses
but change those recipes, you can use <filename>.bbappend</filename> files.
All new recipes and append files for your layer must go in the layer’s
<filename>recipes-bsp</filename>, <filename>recipes-kernel</filename>,
<filename>recipes-core</filename>, and
<filename>recipes-graphics</filename> directories.
</para>
<section id='changing-recipes-bsp'>
<title>Changing&nbsp;&nbsp;<filename>recipes-bsp</filename></title>
<para>
First, let's look at <filename>recipes-bsp</filename>.
For this example we are not adding any new BSP recipes.
And, we only need to remove the formfactor we do not want and change the name of
the remaining one that doesn't support EMGD.
These commands take care of the <filename>recipes-bsp</filename> recipes:
<literallayout class='monospaced'>
$ rm -rf meta-mymachine/recipes-bsp/formfactor/formfactor/fri2
$ mv meta-mymachine/recipes-bsp/formfactor/formfactor/fri2-noemgd/ \
meta-mymachine/recipes-bsp/formfactor/formfactor/mymachine
</literallayout>
</para>
</section>
<section id='changing-recipes-graphics'>
<title>Changing&nbsp;&nbsp;<filename>recipes-graphics</filename></title>
<para>
Now let's look at <filename>recipes-graphics</filename>.
For this example we want to remove anything that supports EMGD and
be sure to rename remaining directories appropriately.
The following commands clean up the <filename>recipes-graphics</filename> directory:
<literallayout class='monospaced'>
$ rm -rf meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/fri2
$ mv meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/fri2-noemgd \
meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/mymachine
</literallayout>
</para>
<para>
At this point the <filename>recipes-graphics</filename> directory just has files that
support Video Electronics Standards Association (VESA) graphics modes and not EMGD.
</para>
</section>
<section id='changing-recipes-kernel'>
<title>Changing&nbsp;&nbsp;<filename>recipes-kernel</filename></title>
<para>
Finally, let's look at <filename>recipes-kernel</filename> changes.
Recall that the BSP uses the <filename>linux-yocto</filename> kernel as determined
earlier in the <filename>mymachine.conf</filename>.
The recipe for that kernel is not located in the
BSP layer but rather in the Source Directory at
<filename>meta/recipes-kernel/linux</filename> and is
named <filename>linux-yocto_3.4.bb</filename>.
The <filename>SRCREV_machine</filename> and <filename>SRCREV_meta</filename>
statements point to the exact commits used by the Yocto Project development team
in their source repositories that identify the right kernel for our hardware.
In other words, the <filename>SRCREV</filename> values are simply Git commit
IDs that identify which commit on each
of the kernel branches (machine and meta) will be checked out and used to build
the kernel.
</para>
<para>
However, in the <filename>meta-mymachine</filename> layer in
<filename>recipes-kernel/linux</filename> resides a <filename>.bbappend</filename>
file named <filename>linux-yocto_3.4.bbappend</filename> that
appends the information to the recipe of the same name
that is found in <filename>meta/recipes-kernel/linux</filename>.
Thus, the <filename>SRCREV</filename> statements in our
<filename>mymachine</filename> append file override
the more general statements found in the more general recipe.
</para>
<para>
The <filename>SRCREV</filename> statements in the
<filename>mymachine</filename> append file currently identify
the kernel that supports the Fish River Island 2 BSP with and without EMGD support.
Here are the statements:
<note>The commit ID strings used in this manual might not match the actual commit
ID strings found in the <filename>linux-yocto_3.4.bbappend</filename> file.
For the example, this difference does not matter.</note>
<literallayout class='monospaced'>
SRCREV_machine_pn-linux-yocto_fri2 ?= \
"59c3ff750831338d05ab67d5efd7fc101c451aff"
#SRCREV_meta_pn-linux-yocto_fri2 ?= \
"c5bddf8ea379406ffec550528e17b777a0eba24b"
SRCREV_machine_pn-linux-yocto_fri2-noemgd ?= \
"59c3ff750831338d05ab67d5efd7fc101c451aff"
#SRCREV_meta_pn-linux-yocto_fir2-noemgd ?= \
"c5bddf8ea379406ffec550528e17b777a0eba24b"
</literallayout>
<note>The <filename>SRCREV_meta_pn-linux-yocto_fir2-noemgd</filename>
statements in the <filename>mymachine</filename> append file,
which originated from the Fish River Island 2 BSP, are
commented out.
The reason they are not used is because the commit IDs are identical to
those in the general <filename>linux-yocto_3.4.bbappend</filename> recipe,
which is found in <filename>meta/recipes-kernel/linux</filename>.
</note>
</para>
<para>
You will notice that there are two pairs of <filename>SRCREV</filename> statements.
The top pair identifies the kernel that supports
EMGD, which we don’t care about in this example.
The bottom pair identifies the kernel that we will use:
<filename>linux-yocto</filename>.
At this point though, the unique commit strings all are still associated with
Fish River Island 2 and not <filename>meta-mymachine</filename>.
</para>
<para>
To fix this situation in <filename>linux-yocto_3.4.bbappend</filename>
for <filename>mymachine</filename>,
we delete the two <filename>SRCREV</filename> statements that support
EMGD (the top pair).
We also change the remaining pair to specify <filename>mymachine</filename>
and insert the commit identifiers to identify the kernel in which we
are interested, which will be based on the <filename>atom-pc-standard</filename>
kernel.
In this case, because we're working with the &DISTRO_NAME; branch of everything, we
need to use the <filename>SRCREV</filename> values for the atom-pc branch
that are associated with the &DISTRO_NAME; release.
</para>
<para>
To find the machine value, we need to find the <filename>SRCREV</filename>
value that &DISTRO_NAME; uses for the atom-pc branch, which we find in the
<filename>poky/meta-yocto-bsp/recipes-kernel/linux/linux-yocto_3.4.bbappend</filename>
file.
The machine <filename>SRCREV</filename> we want is in the
<filename>SRCREV_machine_atom-pc</filename> variable.
</para>
<para>
The meta <filename>SRCREV</filename> isn't specified in this file, so if you
needed it, you would find it in the base kernel recipe in the
<filename>poky/meta/recipes-kernel/linux/linux-yocto_3.4.bb</filename>.
Recall that for this example the commit ID's for the <filename>SRCREV</filename>
meta statements are identical and do not have to be used in the
<filename>mymachine</filename> append file.
</para>
<para>
Here are the final <filename>SRCREV</filename> statements for the
<filename>mymachine</filename> append file:
<literallayout class='monospaced'>
SRCREV_machine_pn-linux-yocto_mymachine ?= \
"0985844fa6235422c67ef269952fa4e765f252f9"
#SRCREV_meta_pn-linux-yocto_mymachine ?= \
"c5bddf8ea379406ffec550528e17b777a0eba24b"
</literallayout>
</para>
<para>
In this example, we're using the <filename>SRCREV</filename> values we
found already captured in the &DISTRO_NAME; release because we're creating a BSP based on
&DISTRO_NAME;.
If, instead, we had based our BSP on the master branches, we would want to use
the most recent <filename>SRCREV</filename> values taken directly from the kernel's
repository.
We will not be doing that for this example.
However, if you do base a future BSP on master and
if you are familiar with Git repositories, you probably won’t have trouble locating the
exact commit strings in the Yocto Project source repositories you need to change
the <filename>SRCREV</filename> statements.
You can find all the <filename>machine</filename> and <filename>meta</filename>
branch points (commits) for the <filename>linux-yocto-3.4</filename> kernel at
<ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/linux-yocto-3.4'></ulink>.
</para>
<para>
If you need a little more assistance after going to the link then do the following:
<orderedlist>
<listitem><para>Expand the list of branches by clicking <filename>[…]</filename></para></listitem>
<listitem><para>Click on the <filename>standard/default/common-pc/atom-pc</filename>
branch</para></listitem>
<listitem><para>Click on the commit column header to view the top commit</para></listitem>
<listitem><para>Copy the commit string for use in the
<filename>linux-yocto_3.4.bbappend</filename> file</para></listitem>
</orderedlist>
</para>
<para>
For the <filename>SRCREV</filename> statement that points to the <filename>meta</filename>
branch use the same procedure except expand the <filename>meta</filename>
branch in step 2 above.
</para>
<para>
Also in the <filename>linux-yocto_3.4.bbappend</filename> file are
<ulink url='&YOCTO_DOCS_REF_URL;#var-COMPATIBLE_MACHINE'><filename>COMPATIBLE_MACHINE</filename></ulink>,
<ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>,
and
<ulink url='&YOCTO_DOCS_REF_URL;#var-KBRANCH'><filename>KBRANCH</filename></ulink> statements.
Two sets of these exist: one set supports EMGD and one set does not.
Because we are not interested in supporting EMGD those three can be deleted.
The remaining three must be changed so that <filename>mymachine</filename> replaces
<filename>fri2-noemgd</filename> and <filename>fri2</filename>.
</para>
<para>
Because we are using the <filename>atom-pc</filename> branch for this new BSP, we can also find
the exact branch we need for the <filename>KMACHINE</filename>
and <filename>KBRANCH</filename> variables in our new BSP from the value
we find in the
<filename>poky/meta-yocto-bsp/recipes-kernel/linux/linux-yocto_3.4.bbappend</filename>
file we looked at in a previous step.
In this case, the values we want are in the <filename>KMACHINE_atom-pc</filename> variable
and the <filename>KBRANCH_atom-pc</filename> variables in that file.
Here is the final <filename>linux-yocto_3.4.bbappend</filename> file after all
the edits:
<literallayout class='monospaced'>
FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
COMPATIBLE_MACHINE_mymachine = "mymachine"
KMACHINE_mymachine = "atom-pc"
KBRANCH_mymachine = "standard/default/common-pc/atom-pc"
SRCREV_machine_pn-linux-yocto_mymachine ?= \
"f29531a41df15d74be5ad47d958e4117ca9e489e"
SRCREV_meta_pn-linux-yocto_mymachine ?= \
"b14a08f5c7b469a5077c10942f4e1aec171faa9d"
</literallayout>
</para>
</section>
</section>
<section id='bsp-recipe-change-summary'>
<title>BSP Recipe Change Summary</title>
<para>
In summary, the edits to the layer’s recipe files result in removal of any files and
statements that do not support your targeted hardware in addition to the inclusion
of any new recipes you might need.
In this example, it was simply a matter of ridding the new layer
<filename>meta-mymachine</filename> of any code that supported the EMGD features
and making sure we were identifying the kernel that supports our example, which
is the <filename>atom-pc-standard</filename> kernel.
We did not introduce any new recipes to the layer.
</para>
<para>
Finally, it is also important to update the layer’s <filename>README</filename>
file so that the information in it reflects your BSP.
</para>
</section>
</section>
<section id='preparing-for-the-build-app'>
<title>Preparing for the Build</title>
<para>
To get ready to build your image that uses the new layer you need to do the following:
<orderedlist>
<listitem><para>Get the environment ready for the build by sourcing the environment
script.
The environment script is in the top-level of the Source Directory.
The script has the string
<filename>init-build-env</filename> in the file’s name.
For this example, the following command gets the build environment ready:
<literallayout class='monospaced'>
$ source oe-init-build-env yocto-build
</literallayout>
When you source the script, a build directory is created in the current
working directory.
In our example we were in the <filename>poky</filename> directory.
Thus, entering the previous command created the <filename>yocto-build</filename> directory.
If you do not provide a name for the build directory it defaults to
<filename>build</filename>.
The <filename>yocto-build</filename> directory contains a
<filename>conf</filename> directory that has
two configuration files you will need to check: <filename>bblayers.conf</filename>
and <filename>local.conf</filename>.</para></listitem>
<listitem><para>Check and edit the resulting <filename>local.conf</filename> file.
This file minimally identifies the machine for which to build the image by
configuring the <filename>MACHINE</filename> variable.
For this example you must set the variable to mymachine as follows:
<literallayout class='monospaced'>
MACHINE ??= “mymachine”
</literallayout>
You should also be sure any other variables in which you are interested are set.
Some variables to consider are <filename>BB_NUMBER_THREADS</filename>
and <filename>PARALLEL_MAKE</filename>, both of which can greatly reduce your build time
if your development system supports multiple cores.
For development systems that support multiple cores, a good rule of thumb is to set
both the <filename>BB_NUMBER_THREADS</filename> and <filename>PARALLEL_MAKE</filename>
variables to twice the number of cores your system supports.</para></listitem>
<listitem><para>Update the <filename>bblayers.conf</filename> file so that it includes
both the path to your new BSP layer and the path to the
<filename>meta-intel</filename> layer.
In this example, you need to include both these paths as part of the
<filename>BBLAYERS</filename> variable:
<literallayout class='monospaced'>
$HOME/poky/meta-intel
$HOME/poky/meta-intel/meta-mymachine
</literallayout></para></listitem>
</orderedlist>
</para>
<para>
The
<ulink url='&YOCTO_DOCS_REF_URL;#ref-variables-glos'>Variables Glossary</ulink> chapter in the
Yocto Project Reference Manual has more information on configuration variables.
</para>
</section>
<section id='building-the-image-app'>
<title>Building and Booting the Image</title>
<para>
To build the image for our <filename>meta-mymachine</filename> BSP enter the following command
from the same shell from which you ran the setup script.
You should run the <filename>bitbake</filename> command without any intervening shell commands.
For example, moving your working directory around could cause problems.
Here is the command for this example:
<literallayout class='monospaced'>
$ bitbake -k core-image-sato
</literallayout>
</para>
<para>
This command specifies an image that has Sato support and that can be run from a USB device or
from a CD without having to first install anything.
The build process takes significant time and includes thousands of tasks, which are reported
at the console.
If the build results in any type of error you should check for misspellings in the
files you changed or problems with your host development environment such as missing packages.
</para>
<para>
Finally, once you have an image, you can try booting it from a device
(e.g. a USB device).
To prepare a bootable USB device, insert a USB flash drive into your build system and
copy the <filename>.hddimg</filename> file, located in the
<filename>poky/build/tmp/deploy/images</filename>
directory after a successful build to the flash drive.
Assuming the USB flash drive takes device <filename>/dev/sdf</filename>,
use <filename>dd</filename> to copy the live image to it.
For example:
<literallayout class='monospaced'>
# dd if=core-image-sato-mymachine-20111101223904.hddimg of=/dev/sdf
# sync
# eject /dev/sdf
</literallayout>
You should now have a bootable USB flash device.
</para>
<para>
Insert the device
into a bootable USB socket on the target, and power it on.
The system should boot to the Sato graphical desktop.
<footnote><para>Because
this new image is not in any way tailored to the system you're
booting it on, which is assumed to be some sort of atom-pc (netbook) system for this
example, it might not be completely functional though it should at least boot to a text
prompt.
Specifically, it might fail to boot into graphics without some tweaking.
If this ends up being the case, a possible next step would be to replace the
<filename>mymachine.conf</filename>
contents with the contents of <filename>atom-pc.conf</filename> and replace
<filename>xorg.conf</filename> with <filename>atom-pc xorg.conf</filename>
in <filename>meta-yocto</filename> and see if it fares any better.
In any case, following the previous steps will give you a buildable image that
will probably boot on most systems.
Getting things working like you want
them to for your hardware will normally require some amount of experimentation with
configuration settings.</para></footnote>
</para>
<para>
For reference, the sato image produced by the previous steps for &DISTRO_NAME;
should look like the following in terms of size.
If your sato image is much different from this,
you probably made a mistake in one of the above steps:
<literallayout class='monospaced'>
260538368 2012-04-27 01:44 core-image-sato-mymachine-20120427025051.hddimg
</literallayout>
<note>The previous instructions are also present in the README that was copied
from meta-fri2, which should also be updated to reflect the specifics of your
new BSP.
That file and the <filename>README.hardware</filename> file in the top-level
<filename>poky</filename> directory
also provides some suggestions for things to try if booting fails and produces
strange error messages.</note>
</para>
</section>
</appendix>
<!--
vim: expandtab tw=80 ts=4
-->

2
documentation/dev-manual/dev-manual.xml
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@ -80,8 +80,6 @@
<xi:include href="dev-manual-model.xml"/>
<xi:include href="dev-manual-bsp-appendix.xml"/>
<xi:include href="dev-manual-kernel-appendix.xml"/>
</book>