671 lines
34 KiB
XML
671 lines
34 KiB
XML
<!DOCTYPE appendix PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<appendix id='dev-manual-bsp-appendix'>
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<title>BSP Development Example</title>
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<para>
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This appendix provides a complete BSP example.
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The example assumes the following:
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<itemizedlist>
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<listitem><para>No previous preparation or use of the Yocto Project.</para></listitem>
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<listitem><para>Use of the Crown Bay Board Support Package (BSP) as a "base" BSP from
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which to work.
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The example begins with the Crown Bay BSP as the starting point
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but ends by building a new 'atom-pc' BSP, which was based on the Crown Bay BSP.
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</para></listitem>
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<listitem><para>Shell commands assume <filename>bash</filename></para></listitem>
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<listitem><para>Example was developed on an Intel-based Core i7 platform running
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Ubuntu 10.04 LTS released in April of 2010.</para></listitem>
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</itemizedlist>
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</para>
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<section id='getting-local-yocto-project-files-and-bsp-files'>
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<title>Getting Local Yocto Project Files and BSP Files</title>
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<para>
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You need to have the Yocto Project files available on your host system.
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You can get files through tarball extraction or by cloning the <filename>poky</filename>
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Git repository.
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The following paragraphs describe both methods.
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For additional information, see the bulleted item
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"<link linkend='local-yp-release'>Yocto Project Release</link>".
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</para>
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<para>
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As mentioned, one way to get the Yocto Project files is to use Git to clone the
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<filename>poky</filename> repository:
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<literallayout class='monospaced'>
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$ git clone git://git.yoctoproject.org/poky
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$ cd poky
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</literallayout>
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Alternatively, you can start with the downloaded Poky "edison" tarball:
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<literallayout class='monospaced'>
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$ tar xfj poky-edison-6.0.1.tar.bz2
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$ cd poky
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</literallayout>
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<note>If you're using the tarball method, you can ignore all the following steps that
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ask you to carry out Git operations.
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You already have the results of those operations
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in the form of the edison release tarballs.
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Consequently, there is nothing left to do other than extract those tarballs into the
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proper locations.</note>
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</para>
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<para>
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Once you have the local <filename>poky</filename> Git repository set up,
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you have many development branches from which you can work.
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From inside the repository you can see the branch names and the tag names used
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in the Git repository using either of the following two commands:
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<literallayout class='monospaced'>
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$ git branch -a
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$ git tag -l
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</literallayout>
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For this example we are going to use the Yocto Project 1.1.1 Release, which is code
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named "edison".
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These commands create a local branch named <filename>edison</filename>
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that tracks the remote branch of the same name.
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<literallayout class='monospaced'>
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$ git checkout -b edison origin/edison
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Switched to a new branch 'edison'
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</literallayout>
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</para>
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</section>
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<section id='choosing-a-base-bsp-app'>
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<title>Choosing a Base BSP</title>
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<para>
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For this example, the base BSP is the <trademark class='registered'>Intel</trademark>
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<trademark class='trade'>Atom</trademark> Processor E660 with Intel Platform
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Controller Hub EG20T Development Kit, which is otherwise referred to as "Crown Bay."
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The BSP layer is <filename>meta-crownbay</filename>.
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The base BSP is simply the BSP
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we will be using as a starting point, so don't worry if you don't actually have Crown Bay
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hardware.
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The remainder of the example transforms the base BSP into a BSP that should be
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able to boot on generic atom-pc (netbook) hardware.
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</para>
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<para>
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For information on how to choose a base BSP, see
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"<link linkend='developing-a-board-support-package-bsp'>Developing a Board Support Package (BSP)</link>".
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</para>
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</section>
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<section id='getting-your-base-bsp-app'>
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<title>Getting Your Base BSP</title>
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<para>
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You need to have the base BSP layer on your development system.
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Similar to the local Yocto Project files, you can get the BSP
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layer a couple of different ways:
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download the BSP tarball and extract it, or set up a local Git repository that
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has the Yocto Project BSP layers.
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You should use the same method that you used to get the local Yocto Project files earlier.
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See "<link linkend='getting-setup'>Getting Setup</link>" for information on how to get
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the BSP files.
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</para>
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<para>
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This example assumes the BSP layer will be located within a directory named
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<filename>meta-intel</filename> contained within the <filename>poky</filename>
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parent directory.
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The following steps will automatically create the
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<filename>meta-intel</filename> directory and the contained meta-crownbay
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starting point in both the Git and the tarball cases.
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</para>
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<para>
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If you're using the Git method, you could do the following to create
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the starting layout after you have made sure you are in the <filename>poky</filename>
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directory created in the previous steps:
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<literallayout class='monospaced'>
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$ git clone git://git.yoctoproject.org/meta-intel.git
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$ cd meta-intel
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</literallayout>
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Alternatively, you can start with the downloaded <filename>meta-intel</filename>
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edison tarball.
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Again, be sure that you are already in the <filename>poky</filename> directory
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as described previously:
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<literallayout class='monospaced'>
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$ tar xfj crownbay-noemgd-edison-6.0.1.tar.bz2
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$ cd meta-intel
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</literallayout>
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</para>
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<para>
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The <filename>meta-intel</filename> directory contains all the metadata
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that supports BSP creation.
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If you're using the Git method, the following
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step will switch to the edison metadata.
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If you're using the tarball method, you already have the correct metadata and can
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skip to the next step.
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Because <filename>meta-intel</filename> is its own Git repository, you will want
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to be sure you are in the appropriate branch for your work.
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For this example we are going to use the <filename>edison</filename> branch.
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<literallayout class='monospaced'>
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$ git checkout -b edison origin/edison
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Switched to a new branch 'edison'
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</literallayout>
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</para>
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</section>
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<section id='making-a-copy-of-the-base bsp-to-create-your-new-bsp-layer-app'>
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<title>Making a Copy of the Base BSP to Create Your New BSP Layer</title>
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<para>
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Now that you have the local Yocto Project files and the base BSP files, you need to create a
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new layer for your BSP.
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To create your BSP layer, you simply copy the <filename>meta-crownbay</filename>
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layer to a new layer.
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</para>
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<para>
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For this example, the new layer will be named <filename>meta-mymachine</filename>.
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The name should follow the BSP layer naming convention, which is
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<filename>meta-<name></filename>.
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The following assumes your working directory is <filename>meta-intel</filename>
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inside the local Yocto Project files.
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To start your new layer, just copy the new layer alongside the existing
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BSP layers in the <filename>meta-intel</filename> directory:
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<literallayout class='monospaced'>
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$ cp -a meta-crownbay/ meta-mymachine
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</literallayout>
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</para>
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</section>
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<section id='making-changes-to-your-bsp-app'>
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<title>Making Changes to Your BSP</title>
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<para>
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Right now you have two identical BSP layers with different names:
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<filename>meta-crownbay</filename> and <filename>meta-mymachine</filename>.
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You need to change your configurations so that they work for your new BSP and
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your particular hardware.
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The following sections look at each of these areas of the BSP.
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</para>
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<section id='changing-the-bsp-configuration'>
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<title>Changing the BSP Configuration</title>
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<para>
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We will look first at the configurations, which are all done in the layer’s
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<filename>conf</filename> directory.
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</para>
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<para>
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First, since in this example the new BSP will not support EMGD, we will get rid of the
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<filename>crownbay.conf</filename> file and then rename the
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<filename>crownbay-noemgd.conf</filename> file to <filename>mymachine.conf</filename>.
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Much of what we do in the configuration directory is designed to help the Yocto Project
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build system work with the new layer and to be able to find and use the right software.
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The following two commands result in a single machine configuration file named
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<filename>mymachine.conf</filename>.
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<literallayout class='monospaced'>
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$ rm meta-mymachine/conf/machine/crownbay.conf
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$ mv meta-mymachine/conf/machine/crownbay-noemgd.conf \
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meta-mymachine/conf/machine/mymachine.conf
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</literallayout>
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</para>
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<para>
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Next, we need to make changes to the <filename>mymachine.conf</filename> itself.
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The only changes we want to make for this example are to the comment lines.
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Changing comments, of course, is never strictly necessary, but it's alway good form to make
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them reflect reality as much as possible.
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Here, simply substitute the Crown Bay name with an appropriate name for the BSP
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(<filename>mymachine</filename> in this case) and change the description to
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something that describes your hardware.
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</para>
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<para>
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Note that inside the <filename>mymachine.conf</filename> is the
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<filename>PREFERRED_PROVIDER_virtual/kernel</filename> statement.
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This statement identifies the kernel that the BSP is going to use.
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In this case, the BSP is using <filename>linux-yocto</filename>, which is the
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current Linux Yocto kernel based on the Linux 3.0 release.
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</para>
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<para>
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The next configuration file in the new BSP layer we need to edit is
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<filename>meta-mymachine/conf/layer.conf</filename>.
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This file identifies build information needed for the new layer.
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You can see the
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"<ulink url='http://www.yoctoproject.org/docs/1.1.1/bsp-guide/bsp-guide.html#bsp-filelayout-layer'>Layer Configuration File</ulink>" section in
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<ulink url='http://www.yoctoproject.org/docs/1.1.1/bsp-guide/bsp-guide.html'>The Board
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Support Packages (BSP) Development Guide</ulink>
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for more information on this configuration file.
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Basically, we are changing the existing statements to work with our BSP.
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</para>
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<para>
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The file contains these statements that reference the Crown Bay BSP:
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<literallayout class='monospaced'>
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BBFILE_COLLECTIONS += "crownbay"
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BBFILE_PATTERN_crownbay := "^${LAYERDIR}/"
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BBFILE_PRIORITY_crownbay = "6"
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</literallayout>
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</para>
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<para>
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Simply substitute the machine string name <filename>crownbay</filename>
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with the new machine name <filename>mymachine</filename> to get the following:
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<literallayout class='monospaced'>
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BBFILE_COLLECTIONS += "mymachine"
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BBFILE_PATTERN_mymachine := "^${LAYERDIR}/"
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BBFILE_PRIORITY_mymachine = "6"
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</literallayout>
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</para>
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</section>
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<section id='changing-the-recipes-in-your-bsp'>
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<title>Changing the Recipes in Your BSP</title>
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<para>
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Now we will take a look at the recipes in your new layer.
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The standard BSP structure has areas for BSP, graphics, core, and kernel recipes.
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When you create a BSP, you use these areas for appropriate recipes and append files.
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Recipes take the form of <filename>.bb</filename> files.
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If you want to leverage the existing recipes the Yocto Project build system uses
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but change those recipes, you can use <filename>.bbappend</filename> files.
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All new recipes and append files for your layer must go in the layer’s
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<filename>recipes-bsp</filename>, <filename>recipes-kernel</filename>,
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<filename>recipes-core</filename>, and
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<filename>recipes-graphics</filename> directories.
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</para>
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<section id='changing-recipes-bsp'>
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<title>Changing <filename>recipes-bsp</filename></title>
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<para>
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First, let's look at <filename>recipes-bsp</filename>.
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For this example we are not adding any new BSP recipes.
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And, we only need to remove the formfactor we do not want and change the name of
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the remaining one that doesn't support EMGD.
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These commands take care of the <filename>recipes-bsp</filename> recipes:
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<literallayout class='monospaced'>
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$ rm -rf meta-mymachine/recipes-bsp/formfactor/formfactor/crownbay
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$ mv meta-mymachine/recipes-bsp/formfactor/formfactor/crownbay-noemgd/ \
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meta-mymachine/recipes-bsp/formfactor/formfactor/mymachine
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</literallayout>
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</para>
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</section>
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<section id='changing-recipes-graphics'>
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<title>Changing <filename>recipes-graphics</filename></title>
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<para>
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Now let's look at <filename>recipes-graphics</filename>.
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For this example we want to remove anything that supports EMGD and
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be sure to rename remaining directories appropriately.
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The following commands clean up the <filename>recipes-graphics</filename> directory:
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<literallayout class='monospaced'>
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$ rm -rf meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/crownbay
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$ mv meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/crownbay-noemgd \
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meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/mymachine
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</literallayout>
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</para>
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<para>
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At this point the <filename>recipes-graphics</filename> directory just has files that
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support Video Electronics Standards Association (VESA) graphics modes and not EMGD.
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</para>
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</section>
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<section id='changing-recipes-core'>
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<title>Changing <filename>recipes-core</filename></title>
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<para>
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Now let's look at changes in <filename>recipes-core</filename>.
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The file <filename>task-core-tools.bbappend</filename> in
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<filename>recipes-core/tasks</filename> appends the similarly named recipe
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located in the local Yocto Project files at
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<filename>meta/recipes-core/tasks</filename>.
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The "append" file in our layer right now is Crown Bay-specific and supports
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EMGD and non-EMGD.
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Here are the contents of the file:
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<literallayout class='monospaced'>
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RRECOMMENDS_task-core-tools-profile_append_crownbay = " systemtap"
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RRECOMMENDS_task-core-tools-profile_append_crownbay-noemgd = " systemtap"
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</literallayout>
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</para>
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<para>
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The <filename>RRECOMMENDS</filename> statements list packages that
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extend usability.
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The first <filename>RRECOMMENDS</filename> statement can be removed, while the
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second one can be changed to reflect <filename>meta-mymachine</filename>:
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<literallayout class='monospaced'>
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RRECOMMENDS_task-core-tools-profile_append_mymachine = " systemtap"
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</literallayout>
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</para>
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</section>
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<section id='changing-recipes-kernel'>
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<title>Changing <filename>recipes-kernel</filename></title>
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<para>
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Finally, let's look at <filename>recipes-kernel</filename> changes.
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Recall that the BSP uses the <filename>linux-yocto</filename> kernel as determined
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earlier in the <filename>mymachine.conf</filename>.
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The recipe for that kernel is not located in the
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BSP layer but rather in the local Yocto Project files at
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<filename>meta/recipes-kernel/linux</filename> and is
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named <filename>linux-yocto_3.0.bb</filename>.
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The <filename>SRCREV_machine</filename> and <filename>SRCREV_meta</filename>
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statements point to the exact commits used by the Yocto Project development team
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in their source repositories that identify the right kernel for our hardware.
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In other words, the <filename>SRCREV</filename> values are simply Git commit
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IDs that identify which commit on each
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of the kernel branches (machine and meta) will be checked out and used to build
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the kernel.
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</para>
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<para>
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However, in the <filename>meta-mymachine</filename> layer in
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<filename>recipes-kernel/linux</filename> resides a <filename>.bbappend</filename>
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file named <filename>linux-yocto_3.0.bbappend</filename> that
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is appended to the recipe of the same name in <filename>meta/recipes-kernel/linux</filename>.
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Thus, the <filename>SRCREV</filename> statements in the "append" file override
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the more general statements found in <filename>meta</filename>.
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</para>
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<para>
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The <filename>SRCREV</filename> statements in the "append" file currently identify
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the kernel that supports the Crown Bay BSP with and without EMGD support.
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Here are the statements:
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<literallayout class='monospaced'>
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SRCREV_machine_pn-linux-yocto_crownbay ?= \
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"2247da9131ea7e46ed4766a69bb1353dba22f873"
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SRCREV_meta_pn-linux-yocto_crownbay ?= \
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"d05450e4aef02c1b7137398ab3a9f8f96da74f52"
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SRCREV_machine_pn-linux-yocto_crownbay-noemgd ?= \
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"2247da9131ea7e46ed4766a69bb1353dba22f873"
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SRCREV_meta_pn-linux-yocto_crownbay-noemgd ?= \
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"d05450e4aef02c1b7137398ab3a9f8f96da74f52"
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</literallayout>
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</para>
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<para>
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You will notice that there are two pairs of <filename>SRCREV</filename> statements.
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The top pair identifies the kernel that supports
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EMGD, which we don’t care about in this example.
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The bottom pair identifies the kernel that we will use:
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<filename>linux-yocto</filename>.
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At this point though, the unique commit strings all are still associated with
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Crown Bay and not <filename>meta-mymachine</filename>.
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</para>
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<para>
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To fix this situation in <filename>linux-yocto_3.0.bbappend</filename>,
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we delete the two <filename>SRCREV</filename> statements that support
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EMGD (the top pair).
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We also change the remaining pair to specify <filename>mymachine</filename>
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and insert the commit identifiers to identify the kernel in which we
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are interested, which will be based on the <filename>atom-pc-standard</filename>
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kernel.
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In this case, because we're working with the edison branch of everything, we
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need to use the <filename>SRCREV</filename> values for the atom-pc branch
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that are associated with the edison release.
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To find those values, we need to find the <filename>SRCREV</filename>
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values that edison uses for the atom-pc branch, which we find in the
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<filename>poky/meta-yocto/recipes-kernel/linux/linux-yocto_3.0.bbappend</filename>
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file.
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</para>
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<para>
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The machine <filename>SRCREV</filename> we want is in the
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<filename>SRCREV_machine_atom-pc</filename> variable.
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The meta <filename>SRCREV</filename> isn't specified in this file, so it must be
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specified in the base kernel recipe in the
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<filename>poky/meta/recipes-kernel/linux/linux-yocto_3.0.bb</filename>
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file, in the <filename>SRCREV_meta variable</filename> found there.
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It happens to be the same as the value we already inherited from the
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<filename>meta-crownbay</filename> BSP.
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Here are the final <filename>SRCREV</filename> statements:
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<literallayout class='monospaced'>
|
||
SRCREV_machine_pn-linux-yocto_mymachine ?= \
|
||
"1e18e44adbe79b846e382370eb29bc4b8cd5a1a0"
|
||
SRCREV_meta_pn-linux-yocto_mymachine ?= \
|
||
"d05450e4aef02c1b7137398ab3a9f8f96da74f52"
|
||
</literallayout>
|
||
</para>
|
||
|
||
<para>
|
||
In this example, we're using the <filename>SRCREV</filename> values we
|
||
found already captured in the edison release because we're creating a BSP based on
|
||
edison.
|
||
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 repo.
|
||
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-3.0</filename> kernel at
|
||
<ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-3.0'></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>yocto/standard/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_3.0.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_3.0.bbappend</filename> file are
|
||
<filename>COMPATIBLE_MACHINE</filename>, <filename>KMACHINE</filename>,
|
||
and <filename>KERNEL_FEATURES</filename> 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>crownbay-noemgd</filename> and <filename>crownbay</filename>.
|
||
Because we are using the atom-pc branch for this new BSP, we can also find
|
||
the exact branch we need for the KMACHINE variable in our new BSP from the value
|
||
we find in the
|
||
<filename>poky/meta-yocto/recipes-kernel/linux/linux-yocto_3.0.bbappend</filename>
|
||
file we looked at in a previous step.
|
||
In this case, the value we want is in the KMACHINE_atom-pc variable in that file.
|
||
Here is the final <filename>linux-yocto_3.0.bbappend</filename> file after all
|
||
the edits:
|
||
<literallayout class='monospaced'>
|
||
FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
|
||
|
||
COMPATIBLE_MACHINE_mymachine = "mymachine"
|
||
KMACHINE_mymachine = "yocto/standard/common-pc/atom-pc"
|
||
KERNEL_FEATURES_append_mymachine += " cfg/smp.scc"
|
||
|
||
SRCREV_machine_pn-linux-yocto_mymachine ?= \
|
||
"1e18e44adbe79b846e382370eb29bc4b8cd5a1a0"
|
||
SRCREV_meta_pn-linux-yocto_mymachine ?= \
|
||
"d05450e4aef02c1b7137398ab3a9f8f96da74f52"
|
||
</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-machine</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 local Yocto Project files
|
||
directory structure.
|
||
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>yocot-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 you are using a multi-threaded development system (e.g. values of
|
||
<filename>8</filename> and <filename>j 6</filename>, respectively are optimal
|
||
for a development machine that has four available cores).</para></listitem>
|
||
<listitem><para>Update the <filename>bblayers.conf</filename> file so that it includes
|
||
the path to your new BSP layer.
|
||
In this example you need to include the pathname to <filename>meta-mymachine</filename>.
|
||
For this example the
|
||
<filename>BBLAYERS</filename> variable in the file would need to include the following path:
|
||
<literallayout class='monospaced'>
|
||
$HOME/poky/meta-intel/meta-mymachine
|
||
</literallayout></para></listitem>
|
||
</orderedlist>
|
||
</para>
|
||
|
||
<para>
|
||
The appendix
|
||
<ulink url='http://www.yoctoproject.org/docs/1.1.1/poky-ref-manual/poky-ref-manual.html#ref-variables-glos'>
|
||
Reference: Variables Glossary</ulink> 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>.hddimage</filename>, 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/sdc</filename>,
|
||
use <filename>dd</filename> to copy the live image to it.
|
||
For example:
|
||
<literallayout class='monospaced'>
|
||
# dd if=core-image-sato-mymachine-20120111232235.hddimg of=/dev/sdc
|
||
# sync
|
||
# eject /dev/sdc
|
||
</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.
|
||
</para>
|
||
|
||
<para>
|
||
For reference, the sato image produced by the previous steps for edison
|
||
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'>
|
||
358709248 2012-01-11 20:43 core-image-sato-mymachine-20120111232235.hddimg
|
||
</literallayout>
|
||
<note>The previous instructions are also present in the README that was copied
|
||
from meta-crownbay, 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>
|
||
|
||
<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 should
|
||
probably give you a buildable and bootable image.
|
||
Getting things working like you want
|
||
them to for your hardware will normally require some amount of experimentation with
|
||
configuration settings.
|
||
</para>
|
||
</section>
|
||
</appendix>
|
||
|
||
|
||
<!--
|
||
vim: expandtab tw=80 ts=4
|
||
-->
|