2021 lines
109 KiB
XML
2021 lines
109 KiB
XML
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
|
|
[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
|
|
|
|
<chapter id='extendpoky'>
|
|
|
|
<title>Common Tasks</title>
|
|
<para>
|
|
This chapter describes standard tasks such as adding new
|
|
software packages, extending or customizing images or porting the Yocto Project to
|
|
new hardware (adding a new machine).
|
|
The chapter also describes ways to modify package source code, combine multiple
|
|
versions of library files into a single image, and handle a package name alias.
|
|
Finally, the chapter contains advice about how to make changes to the
|
|
Yocto Project to achieve the best results.
|
|
</para>
|
|
|
|
<section id="understanding-and-creating-layers">
|
|
<title>Understanding and Creating Layers</title>
|
|
|
|
<para>
|
|
The Yocto Project build system supports organizing <link linkend='metadata'>metadata</link>
|
|
into multiple layers.
|
|
Layers allow you to isolate different types of customizations from each other.
|
|
You might find it tempting to keep everything in one layer when working on a single project.
|
|
However, the more modular you organize your metadata, the easier it is to cope with future changes.
|
|
</para>
|
|
|
|
<para>
|
|
To illustrate how layers are used to keep things modular, consider machine customizations.
|
|
These types of customizations typically reside in a BSP Layer.
|
|
Furthermore, the machine customizations should be isolated from recipes and metadata that support
|
|
a new GUI environment, for example.
|
|
This situation gives you a couple a layers: one for the machine configurations, and one for the
|
|
GUI environment.
|
|
It is important to understand, however, that the BSP layer can still make machine-specific
|
|
additions to recipes within the GUI environment layer without polluting the GUI layer itself
|
|
with those machine-specific changes.
|
|
You can accomplish this through a recipe that is a BitBake append
|
|
(<filename>.bbappend</filename>) file, which is described later in this section.
|
|
</para>
|
|
|
|
<para>
|
|
</para>
|
|
|
|
<section id='yocto-project-layers'>
|
|
<title>Yocto Project Layers</title>
|
|
|
|
<para>
|
|
The Yocto Project contains several layers right out of the box.
|
|
You can easily identify a layer in the Yocto Project by the name of its folder.
|
|
Folders that are layers begin with the string <filename>meta</filename>.
|
|
For example, when you set up the <link linkend='yocto-project-files'>Yocto Project Files</link>
|
|
structure, you will see several layers: <filename>meta</filename>, <filename>meta-demoapps</filename>,
|
|
<filename>meta-skeleton</filename>, and <filename>meta-yocto</filename>.
|
|
Each of these folders is a layer.
|
|
</para>
|
|
|
|
<para>
|
|
Furthermore, if you set up a local copy of the <filename>meta-intel</filename> Git repository
|
|
and then explore that folder, you will discover many BSP layers within the
|
|
<filename>meta-intel</filename> layer.
|
|
For more information on BSP layers, see the
|
|
"<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>"
|
|
section in the Yocto Project Board Support Package (BSP) Developer's Guide.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='creating-your-own-layer'>
|
|
<title>Creating Your Own Layer</title>
|
|
|
|
<para>
|
|
It is very easy to create your own layer to use with the Yocto Project.
|
|
Follow these general steps to create your layer:
|
|
<orderedlist>
|
|
<listitem><para><emphasis>Check Existing Layers:</emphasis> Before creating a new layer,
|
|
you should be sure someone has not already created a layer containing the metadata
|
|
you need.
|
|
You can see the
|
|
<ulink url='&OE_HOME_URL;/wiki/LayerIndex'><filename>LayerIndex</filename></ulink>
|
|
for a list of layers from the OpenEmbedded community that can be used in the
|
|
Yocto Project.</para></listitem>
|
|
<listitem><para><emphasis>Create a Directory:</emphasis> Create the directory
|
|
for your layer.
|
|
Traditionally, prepend the name of the folder with the string
|
|
<filename>meta</filename>.
|
|
For example:
|
|
<literallayout class='monospaced'>
|
|
meta-mylayer
|
|
meta-GUI_xyz
|
|
meta-mymachine
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Create a Layer Configuration File:</emphasis> Inside your new
|
|
layer folder, you need to create a <filename>conf/layer.conf</filename> file.
|
|
It is easiest to take an existing layer configuration file and copy that to your
|
|
layer's <filename>conf</filename> directory and then modify the file as needed.</para>
|
|
<para>The <filename>meta-yocto/conf/layer.conf</filename> file demonstrates the
|
|
required syntax:
|
|
<literallayout class='monospaced'>
|
|
# We have a conf and classes directory, add to BBPATH
|
|
BBPATH := "${LAYERDIR}:${BBPATH}"
|
|
|
|
# We have a packages directory, add to BBFILES
|
|
BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
|
|
${LAYERDIR}/recipes-*/*/*.bbappend"
|
|
|
|
BBFILE_COLLECTIONS += "yocto"
|
|
BBFILE_PATTERN_yocto := "^${LAYERDIR}/"
|
|
BBFILE_PRIORITY_yocto = "5"
|
|
</literallayout></para>
|
|
<para>In the previous example, the recipes for the layers are added to
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILES'>BBFILES</ulink></filename>.
|
|
The
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_COLLECTIONS'>BBFILE_COLLECTIONS</ulink></filename>
|
|
variable is then appended with the layer name.
|
|
The
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PATTERN'>BBFILE_PATTERN</ulink></filename>
|
|
variable is set to a regular expression and is used to match files
|
|
from <filename>BBFILES</filename> into a particular layer.
|
|
In this case, immediate expansion of
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERDIR'>LAYERDIR</ulink></filename>
|
|
sets <filename>BBFILE_PATTERN</filename> to the layer's path.
|
|
The
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PRIORITY'>BBFILE_PRIORITY</ulink></filename>
|
|
variable then assigns a priority to the layer.
|
|
Applying priorities is useful in situations where the same package might appear in multiple
|
|
layers and allows you to choose what layer should take precedence.</para>
|
|
<para>Note the use of the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERDIR'>LAYERDIR</ulink></filename>
|
|
variable with the immediate expansion operator.
|
|
The <filename>LAYERDIR</filename> variable expands to the directory of the current layer and
|
|
requires the immediate expansion operator so that BitBake does not wait to expand the variable
|
|
when it's parsing a different directory.</para>
|
|
<para>Through the use of the <filename>BBPATH</filename> variable,
|
|
BitBake locates <filename>.bbclass</filename> files, configuration
|
|
files, and files that are included with <filename>include</filename>
|
|
and <filename>require</filename> statements.
|
|
For these cases, BitBake uses the first file with the matching name found in
|
|
<filename>BBPATH</filename>.
|
|
This is similar to the way the <filename>PATH</filename> variable is used for binaries.
|
|
We recommend, therefore, that you use unique <filename>.bbclass</filename>
|
|
and configuration file names in your custom layer.</para></listitem>
|
|
<listitem><para><emphasis>Add Content:</emphasis> Depending on the type of layer,
|
|
add the content.
|
|
If the layer adds support for a machine, add the machine configuration in
|
|
a <filename>conf/machine/</filename> file within the layer.
|
|
If the layer adds distro policy, add the distro configuration in a
|
|
<filename>conf/distro/</filename> file with the layer.
|
|
If the layer introduces new recipes, put the recipes you need in
|
|
<filename>recipes-*</filename> subdirectories within the layer.</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
|
|
<para>
|
|
To create layers that are easier to maintain, you should consider the following:
|
|
<itemizedlist>
|
|
<listitem><para>Avoid "overlaying" entire recipes from other layers in your
|
|
configuration.
|
|
In other words, don't copy an entire recipe into your layer and then modify it.
|
|
Use <filename>.bbappend</filename> files to override the parts of the
|
|
recipe you need to modify.</para></listitem>
|
|
<listitem><para>Avoid duplicating include files.
|
|
Use <filename>.bbappend</filename> files for each recipe that uses an include
|
|
file.
|
|
Or, if you are introducing a new recipe that requires the included file, use the
|
|
path relative to the original layer directory to refer to the file.
|
|
For example, use <filename>require recipes-core/somepackage/somefile.inc</filename>
|
|
instead of <filename>require somefile.inc</filename>.
|
|
If you're finding you have to overlay the include file, it could indicate a
|
|
deficiency in the include file in the layer to which it originally belongs.
|
|
If this is the case, you need to address that deficiency instead of overlaying
|
|
the include file.
|
|
For example, consider how Qt 4 database support plugins are configured.
|
|
The Yocto Project does not have MySQL or PostgreSQL, however OpenEmbedded's
|
|
layer <filename>meta-oe</filename> does.
|
|
Consequently, <filename>meta-oe</filename> uses <filename>.bbappend</filename>
|
|
files to modify the <filename>QT_SQL_DRIVER_FLAGS</filename> variable to enable
|
|
the appropriate plugins.
|
|
This variable was added to the <filename>qt4.inc</filename> include file in
|
|
The Yocto Project specifically to allow the <filename>meta-oe</filename> layer
|
|
to be able to control which plugins are built.</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
We also recommend the following:
|
|
<itemizedlist>
|
|
<listitem><para>Store custom layers in a Git repository that uses the
|
|
<filename>meta-<layer_name></filename> format.</para></listitem>
|
|
<listitem><para>Clone the repository alongside other <filename>meta</filename>
|
|
directories in the Yocto Project source files area.</para></listitem>
|
|
</itemizedlist>
|
|
Following these recommendations keeps your Yocto Project files area and
|
|
its configuration entirely inside the Yocto Project's core base.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='enabling-your-layer'>
|
|
<title>Enabling Your Layer</title>
|
|
|
|
<para>
|
|
Before the Yocto Project build system can use your new layer, you need to enable it.
|
|
To enable your layer, simply add your layer's path to the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'>BBLAYERS</ulink></filename>
|
|
variable in your <filename>conf/bblayers.conf</filename> file, which is found in the
|
|
<link linkend='yocto-project-build-directory'>Yocto Project Build Directory</link>.
|
|
The following example shows how to enable a layer named <filename>meta-mylayer</filename>:
|
|
<literallayout class='monospaced'>
|
|
LCONF_VERSION = "1"
|
|
|
|
BBFILES ?= ""
|
|
BBLAYERS = " \
|
|
/path/to/poky/meta \
|
|
/path/to/poky/meta-yocto \
|
|
/path/to/poky/meta-mylayer \
|
|
"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
BitBake parses each <filename>conf/layer.conf</filename> file as specified in the
|
|
<filename>BBLAYERS</filename> variable within the <filename>conf/bblayers.conf</filename>
|
|
file.
|
|
During the processing of each <filename>conf/layer.conf</filename> file, BitBake adds the
|
|
recipes, classes and configurations contained within the particular layer to the Yocto
|
|
Project.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='using-bbappend-files'>
|
|
<title>Using .bbappend Files</title>
|
|
|
|
<para>
|
|
Recipes used to append metadata to other recipes are called BitBake append files.
|
|
BitBake append files use the <filename>.bbappend</filename> file type suffix, while
|
|
underlying recipes to which metadata is being appended use the
|
|
<filename>.bb</filename> file type suffix.
|
|
</para>
|
|
|
|
<para>
|
|
A <filename>.bbappend</filename> file allows your layer to make additions or
|
|
changes to the content of another layer's recipe without having to copy the other
|
|
recipe into your layer.
|
|
Your <filename>.bbappend</filename> file resides in your layer, while the underlying
|
|
<filename>.bb</filename> recipe file to which you are appending metadata
|
|
resides in a different layer.
|
|
</para>
|
|
|
|
<para>
|
|
Append files files must have the same name as the underlying recipe.
|
|
For example, the append file <filename>someapp_1.1.bbappend</filename> must
|
|
apply to <filename>someapp_1.1.bb</filename>.
|
|
This means the original recipe and append file names are version number specific.
|
|
If the underlying recipe is renamed to update to a newer version, the
|
|
corresponding <filename>.bbappend</filename> file must be renamed as well.
|
|
During the build process, BitBake displays an error on starting if it detects a
|
|
<filename>.bbappend</filename> file that does not have an underlying recipe
|
|
with a matching name.
|
|
</para>
|
|
|
|
<para>
|
|
Being able to append information to an existing recipe not only avoids duplication,
|
|
but also automatically applies recipe changes in a different layer to your layer.
|
|
If you were copying recipes, you would have to manually merge changes as they occur.
|
|
</para>
|
|
|
|
<para>
|
|
As an example, consider the main formfactor recipe and a corresponding formfactor
|
|
append file both from the
|
|
<link linkend='yocto-project-files'>Yocto Project Files</link>.
|
|
Here is the main formfactor recipe, which is named <filename>formfactor_0.0.bb</filename> and
|
|
located in the meta layer at <filename>meta/bsp-recipes/formfactor</filename>:
|
|
<literallayout class='monospaced'>
|
|
DESCRIPTION = "Device formfactor information"
|
|
SECTION = "base"
|
|
LICENSE = "MIT"
|
|
LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=3f40d7994397109285ec7b81fdeb3b58 \
|
|
file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
|
|
PR = "r19"
|
|
|
|
SRC_URI = "file://config file://machconfig"
|
|
S = "${WORKDIR}"
|
|
|
|
PACKAGE_ARCH = "${MACHINE_ARCH}"
|
|
INHIBIT_DEFAULT_DEPS = "1"
|
|
|
|
do_install() {
|
|
# Only install file if it has a contents
|
|
install -d ${D}${sysconfdir}/formfactor/
|
|
install -m 0644 ${S}/config ${D}${sysconfdir}/formfactor/
|
|
if [ -s "${S}/machconfig" ]; then
|
|
install -m 0644 ${S}/machconfig ${D}${sysconfdir}/formfactor/
|
|
fi
|
|
}
|
|
</literallayout>
|
|
Here is the append file, which is named <filename>formfactor_0.0.bbappend</filename> and is from the
|
|
Crown Bay BSP Layer named <filename>meta-intel/meta-crownbay</filename>:
|
|
<literallayout class='monospaced'>
|
|
FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
|
|
|
|
PRINC = "1"
|
|
</literallayout>
|
|
This example adds or overrides files in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
|
|
within a <filename>.bbappend</filename> by extending the path BitBake uses to search for files.
|
|
The most reliable way to do this is by prepending the
|
|
<filename>FILESEXTRAPATHS</filename> variable.
|
|
For example, if you have your files in a directory that is named the same as your package
|
|
(<ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>),
|
|
you can add this directory by adding the following to your <filename>.bbappend</filename> file:
|
|
<literallayout class='monospaced'>
|
|
FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
|
|
</literallayout>
|
|
Using the immediate expansion assignment operator <filename>:=</filename> is important because
|
|
of the reference to <filename>THISDIR</filename>.
|
|
The trailing colon character is important as it ensures that items in the list remain
|
|
colon-separated.
|
|
<note>BitBake automatically defines the <filename>THISDIR</filename> variable.
|
|
You should never set this variable yourself.
|
|
Using <filename>_prepend</filename> ensures your path will be searched prior to other
|
|
paths in the final list.
|
|
</note>
|
|
</para>
|
|
|
|
<para>
|
|
For another example on how to use a <filename>.bbappend</filename> file, see the
|
|
"<link linkend='changing-recipes-kernel'>Changing <filename>recipes-kernel</filename></link>"
|
|
section.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='prioritizing-your-layer'>
|
|
<title>Prioritizing Your Layer</title>
|
|
|
|
<para>
|
|
Each layer is assigned a priority value.
|
|
Priority values control which layer takes precedence if there are recipe files with
|
|
the same name in multiple layers.
|
|
For these cases, the recipe file from the layer with a higher priority number taking precedence.
|
|
Priority values also affect the order in which multiple <filename>.bbappend</filename> files
|
|
for the same recipe are applied.
|
|
You can either specify the priority manually, or allow the build system to calculate it
|
|
based on the layer's dependencies.
|
|
</para>
|
|
|
|
<para>
|
|
To specify the layer's priority manually, use the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PRIORITY'><filename>BBFILE_PRIORITY</filename></ulink>
|
|
variable.
|
|
For example:
|
|
<literallayout class='monospaced'>
|
|
BBFILE_PRIORITY := "1"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<note>
|
|
<para>It is possible for a recipe with a lower version number
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
|
|
in a layer that has a higher priority to take precedence.</para>
|
|
<para>Also, the layer priority does not currently affect the precedence order of
|
|
<filename>.conf</filename> or <filename>.bbclass</filename> files.
|
|
Future versions of BitBake might address this.</para>
|
|
</note>
|
|
</section>
|
|
|
|
<section id='managing-layers'>
|
|
<title>Managing Layers</title>
|
|
|
|
<para>
|
|
You can use the BitBake layer management tool to provide a view into the structure of
|
|
recipes across a multi-layer project.
|
|
Being able to generate output that reports on configured layers with their paths and
|
|
priorities and on <filename>.bbappend</filename> files and their applicable recipes
|
|
can help to reveal potential problems.
|
|
</para>
|
|
|
|
<para>
|
|
Use the following form when running the layer management tool.
|
|
<literallayout class='monospaced'>
|
|
$ bitbake-layers <command> [arguments]
|
|
</literallayout>
|
|
The following list describes the available commands:
|
|
<itemizedlist>
|
|
<listitem><para><filename><emphasis>help:</emphasis></filename>
|
|
Displays general help or help on a specified command.</para></listitem>
|
|
<listitem><para><filename><emphasis>show-layers:</emphasis></filename>
|
|
Show the current configured layers.</para></listitem>
|
|
<listitem><para><filename><emphasis>show-recipes:</emphasis></filename>
|
|
Lists available recipes and the layers that provide them.
|
|
</para></listitem>
|
|
<listitem><para><filename><emphasis>show-overlayed:</emphasis></filename>
|
|
Lists overlayed recipes.
|
|
A recipe is overlayed when a recipe with the same name exists in another layer
|
|
that has a higher layer priority.
|
|
</para></listitem>
|
|
<listitem><para><filename><emphasis>show-appends:</emphasis></filename>
|
|
Lists <filename>.bbappend</filename> files and the recipe files to which
|
|
they apply.</para></listitem>
|
|
<listitem><para><filename><emphasis>flatten:</emphasis></filename>
|
|
Flattens the layer configuration into a separate output directory.
|
|
Flattening your layer configuration builds a "flattened" directory that contains
|
|
the contents of all layers, with any overlayed recipes removed and any
|
|
<filename>.bbappend</filename> files appended to the corresponding recipes.
|
|
You might have to perform some manual cleanup of the flattened layer as follows:
|
|
<itemizedlist>
|
|
<listitem><para>Non-recipe files (such as patches) are overwritten.
|
|
The flatten command shows a warning for these files.</para></listitem>
|
|
<listitem><para>Anything beyond the normal layer setup has been added to
|
|
the <filename>layer.conf</filename> file.
|
|
Only the lowest priority layer's <filename>layer.conf</filename> is used.
|
|
</para></listitem>
|
|
<listitem><para>Overridden and appended items from <filename>.bbappend</filename>
|
|
files need to be cleaned up.
|
|
The contents of each <filename>.bbappend</filename> end up in the
|
|
flattened recipe.
|
|
However, if there are appended or changed variable values, you need to tidy
|
|
these up yourself.
|
|
Consider the following example.
|
|
Here, the <filename>bitbake-layers</filename> command adds the line
|
|
<filename>#### bbappended ...</filename> so that you know where the following
|
|
lines originate:
|
|
<literallayout class='monospaced'>
|
|
...
|
|
DESCRIPTION = "A useful utility"
|
|
...
|
|
EXTRA_OECONF = "--enable-something"
|
|
...
|
|
|
|
#### bbappended from meta-anotherlayer ####
|
|
|
|
DESCRIPTION = "Customized utility"
|
|
EXTRA_OECONF += "--enable-somethingelse"
|
|
</literallayout>
|
|
Ideally, you would tidy up these utilities as follows:
|
|
<literallayout class='monospaced'>
|
|
...
|
|
DESCRIPTION = "Customized utility"
|
|
...
|
|
EXTRA_OECONF = "--enable-something --enable-somethingelse"
|
|
...
|
|
</literallayout></para></listitem>
|
|
</itemizedlist></para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-addpkg'>
|
|
<title>Adding a Package</title>
|
|
|
|
<para>
|
|
To add a package into the Yocto Project you need to write a recipe for it.
|
|
Writing a recipe means creating a <filename>.bb</filename> file that sets some
|
|
variables.
|
|
For information on variables that are useful for recipes and for information about recipe naming
|
|
issues, see the
|
|
"<ulink url='&YOCTO_DOCS_REF_URL;#ref-varlocality-recipe-required'>Required</ulink>"
|
|
section of the Yocto Project Reference Manual.
|
|
</para>
|
|
|
|
<para>
|
|
Before writing a recipe from scratch, it is often useful to check
|
|
whether someone else has written one already.
|
|
OpenEmbedded is a good place to look as it has a wider scope and range of packages.
|
|
Because the Yocto Project aims to be compatible with OpenEmbedded, most recipes
|
|
you find there should work in Yocto Project.
|
|
</para>
|
|
|
|
<para>
|
|
For new packages, the simplest way to add a recipe is to base it on a similar
|
|
pre-existing recipe.
|
|
The sections that follow provide some examples that show how to add standard
|
|
types of packages.
|
|
</para>
|
|
|
|
<section id='usingpoky-extend-addpkg-singlec'>
|
|
<title>Single .c File Package (Hello World!)</title>
|
|
|
|
<para>
|
|
Building an application from a single file that is stored locally (e.g. under
|
|
<filename>files/</filename>) requires a recipe that has the file listed in
|
|
the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>
|
|
variable.
|
|
Additionally, you need to manually write the <filename>do_compile</filename> and
|
|
<filename>do_install</filename> tasks.
|
|
The <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename>
|
|
variable defines the
|
|
directory containing the source code, which is set to
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'>
|
|
WORKDIR</ulink></filename> in this case - the directory BitBake uses for the build.
|
|
<literallayout class='monospaced'>
|
|
DESCRIPTION = "Simple helloworld application"
|
|
SECTION = "examples"
|
|
LICENSE = "MIT"
|
|
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
|
|
PR = "r0"
|
|
|
|
SRC_URI = "file://helloworld.c"
|
|
|
|
S = "${WORKDIR}"
|
|
|
|
do_compile() {
|
|
${CC} helloworld.c -o helloworld
|
|
}
|
|
|
|
do_install() {
|
|
install -d ${D}${bindir}
|
|
install -m 0755 helloworld ${D}${bindir}
|
|
}
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
By default, the <filename>helloworld</filename>, <filename>helloworld-dbg</filename>,
|
|
and <filename>helloworld-dev</filename> packages are built.
|
|
For information on how to customize the packaging process, see the
|
|
"<link linkend='splitting-an-application-into-multiple-packages'>Splitting an Application
|
|
into Multiple Packages</link>" section.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-addpkg-autotools'>
|
|
<title>Autotooled Package</title>
|
|
<para>
|
|
Applications that use Autotools such as <filename>autoconf</filename> and
|
|
<filename>automake</filename> require a recipe that has a source archive listed in
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename> and
|
|
also inherits Autotools, which instructs BitBake to use the
|
|
<filename>autotools.bbclass</filename> file, which contains the definitions of all the steps
|
|
needed to build an Autotool-based application.
|
|
The result of the build is automatically packaged.
|
|
And, if the application uses NLS for localization, packages with local information are
|
|
generated (one package per language).
|
|
Following is one example: (<filename>hello_2.3.bb</filename>)
|
|
<literallayout class='monospaced'>
|
|
DESCRIPTION = "GNU Helloworld application"
|
|
SECTION = "examples"
|
|
LICENSE = "GPLv2+"
|
|
LIC_FILES_CHKSUM = "file://COPYING;md5=751419260aa954499f7abaabaa882bbe"
|
|
PR = "r0"
|
|
|
|
SRC_URI = "${GNU_MIRROR}/hello/hello-${PV}.tar.gz"
|
|
|
|
inherit autotools gettext
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
The variable
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'>LIC_FILES_CHKSUM</ulink></filename>
|
|
is used to track source license changes as described in the
|
|
"<ulink url='&YOCTO_DOCS_REF_URL;#usingpoky-configuring-LIC_FILES_CHKSUM'>Track License Change</ulink>" section.
|
|
You can quickly create Autotool-based recipes in a manner similar to the previous example.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-addpkg-makefile'>
|
|
<title>Makefile-Based Package</title>
|
|
|
|
<para>
|
|
Applications that use GNU <filename>make</filename> also require a recipe that has
|
|
the source archive listed in
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>.
|
|
You do not need to add a <filename>do_compile</filename> step since by default BitBake
|
|
starts the <filename>make</filename> command to compile the application.
|
|
If you need additional <filename>make</filename> options you should store them in the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OEMAKE'>EXTRA_OEMAKE</ulink></filename>
|
|
variable.
|
|
BitBake passes these options into the <filename>make</filename> GNU invocation.
|
|
Note that a <filename>do_install</filename> task is still required.
|
|
Otherwise BitBake runs an empty <filename>do_install</filename> task by default.
|
|
</para>
|
|
|
|
<para>
|
|
Some applications might require extra parameters to be passed to the compiler.
|
|
For example, the application might need an additional header path.
|
|
You can accomplish this by adding to the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink></filename> variable.
|
|
The following example shows this:
|
|
<literallayout class='monospaced'>
|
|
CFLAGS_prepend = "-I ${S}/include "
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
In the following example, <filename>mtd-utils</filename> is a makefile-based package:
|
|
<literallayout class='monospaced'>
|
|
DESCRIPTION = "Tools for managing memory technology devices."
|
|
SECTION = "base"
|
|
DEPENDS = "zlib lzo e2fsprogs util-linux"
|
|
HOMEPAGE = "http://www.linux-mtd.infradead.org/"
|
|
LICENSE = "GPLv2"
|
|
LIC_FILES_CHKSUM = "file://COPYING;md5=0636e73ff0215e8d672dc4c32c317bb3 \
|
|
file://include/common.h;beginline=1;endline=17;md5=ba05b07912a44ea2bf81ce409380049c"
|
|
|
|
SRC_URI = "git://git.infradead.org/mtd-utils.git;protocol=git;tag=v${PV}"
|
|
|
|
S = "${WORKDIR}/git/"
|
|
|
|
EXTRA_OEMAKE = "'CC=${CC}' 'CFLAGS=${CFLAGS} -I${S}/include -DWITHOUT_XATTR' \
|
|
'BUILDDIR=${S}'"
|
|
|
|
do_install () {
|
|
oe_runmake install DESTDIR=${D} SBINDIR=${sbindir} MANDIR=${mandir} \
|
|
INCLUDEDIR=${includedir}
|
|
install -d ${D}${includedir}/mtd/
|
|
for f in ${S}/include/mtd/*.h; do
|
|
install -m 0644 $f ${D}${includedir}/mtd/
|
|
done
|
|
}
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='splitting-an-application-into-multiple-packages'>
|
|
<title>Splitting an Application into Multiple Packages</title>
|
|
|
|
<para>
|
|
You can use the variables
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'>PACKAGES</ulink></filename> and
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'>FILES</ulink></filename>
|
|
to split an application into multiple packages.
|
|
</para>
|
|
|
|
<para>
|
|
Following is an example that uses the <filename>libXpm</filename> recipe.
|
|
By default, this recipe generates a single package that contains the library along
|
|
with a few binaries.
|
|
You can modify the recipe to split the binaries into separate packages:
|
|
<literallayout class='monospaced'>
|
|
require xorg-lib-common.inc
|
|
|
|
DESCRIPTION = "X11 Pixmap library"
|
|
LICENSE = "X-BSD"
|
|
LIC_FILES_CHKSUM = "file://COPYING;md5=3e07763d16963c3af12db271a31abaa5"
|
|
DEPENDS += "libxext libsm libxt"
|
|
PR = "r3"
|
|
PE = "1"
|
|
|
|
XORG_PN = "libXpm"
|
|
|
|
PACKAGES =+ "sxpm cxpm"
|
|
FILES_cxpm = "${bindir}/cxpm"
|
|
FILES_sxpm = "${bindir}/sxpm"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
In the previous example, we want to ship the <filename>sxpm</filename>
|
|
and <filename>cxpm</filename> binaries in separate packages.
|
|
Since <filename>bindir</filename> would be packaged into the main
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'>PN</ulink></filename>
|
|
package by default, we prepend the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'>PACKAGES</ulink>
|
|
</filename> variable so additional package names are added to the start of list.
|
|
This results in the extra
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'>FILES</ulink>_*</filename>
|
|
variables then containing information that define which files and
|
|
directories go into which packages.
|
|
Files included by earlier packages are skipped by latter packages.
|
|
Thus, the main
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'>PN</ulink></filename> package
|
|
does not include the above listed files.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='including-static-library-files'>
|
|
<title>Including Static Library Files</title>
|
|
|
|
<para>
|
|
If you are building a library and the library offers static linking, you can control
|
|
which static library files (<filename>*.a</filename> files) get included in the
|
|
built library.
|
|
</para>
|
|
|
|
<para>
|
|
The <filename>PACKAGES</filename> and <filename>FILES_*</filename> variables in the
|
|
<filename>meta/conf/bitbake.conf</filename> configuration file define how files installed
|
|
by the <filename>do_install</filename> task are packaged.
|
|
By default, the <filename>PACKAGES</filename> variable contains
|
|
<filename>${PN}-staticdev</filename>, which includes all static library files.
|
|
<note>
|
|
Previously released versions of the Yocto Project defined the static library files
|
|
through <filename>${PN}-dev</filename>.
|
|
</note>
|
|
Following, is part of the BitBake configuration file.
|
|
You can see where the static library files are defined:
|
|
<literallayout class='monospaced'>
|
|
PACKAGES = "${PN}-dbg ${PN} ${PN}-doc ${PN}-dev ${PN}-staticdev ${PN}-locale"
|
|
PACKAGES_DYNAMIC = "${PN}-locale-*"
|
|
FILES = ""
|
|
|
|
FILES_${PN} = "${bindir}/* ${sbindir}/* ${libexecdir}/* ${libdir}/lib*${SOLIBS} \
|
|
${sysconfdir} ${sharedstatedir} ${localstatedir} \
|
|
${base_bindir}/* ${base_sbindir}/* \
|
|
${base_libdir}/*${SOLIBS} \
|
|
${datadir}/${BPN} ${libdir}/${BPN}/* \
|
|
${datadir}/pixmaps ${datadir}/applications \
|
|
${datadir}/idl ${datadir}/omf ${datadir}/sounds \
|
|
${libdir}/bonobo/servers"
|
|
|
|
FILES_${PN}-doc = "${docdir} ${mandir} ${infodir} ${datadir}/gtk-doc \
|
|
${datadir}/gnome/help"
|
|
SECTION_${PN}-doc = "doc"
|
|
|
|
FILES_${PN}-dev = "${includedir} ${libdir}/lib*${SOLIBSDEV} ${libdir}/*.la \
|
|
${libdir}/*.o ${libdir}/pkgconfig ${datadir}/pkgconfig \
|
|
${datadir}/aclocal ${base_libdir}/*.o"
|
|
SECTION_${PN}-dev = "devel"
|
|
ALLOW_EMPTY_${PN}-dev = "1"
|
|
RDEPENDS_${PN}-dev = "${PN} (= ${EXTENDPKGV})"
|
|
|
|
FILES_${PN}-staticdev = "${libdir}/*.a ${base_libdir}/*.a"
|
|
SECTION_${PN}-staticdev = "devel"
|
|
RDEPENDS_${PN}-staticdev = "${PN}-dev (= ${EXTENDPKGV})"
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-addpkg-postinstalls'>
|
|
<title>Post Install Scripts</title>
|
|
|
|
<para>
|
|
To add a post-installation script to a package, add a <filename>pkg_postinst_PACKAGENAME()
|
|
</filename> function to the <filename>.bb</filename> file and use
|
|
<filename>PACKAGENAME</filename> as the name of the package you want to attach to the
|
|
<filename>postinst</filename> script.
|
|
Normally
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'>PN</ulink></filename>
|
|
can be used, which automatically expands to PACKAGENAME.
|
|
A post-installation function has the following structure:
|
|
<literallayout class='monospaced'>
|
|
pkg_postinst_PACKAGENAME () {
|
|
#!/bin/sh -e
|
|
# Commands to carry out
|
|
}
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
The script defined in the post-installation function is called when the
|
|
root filesystem is created.
|
|
If the script succeeds, the package is marked as installed.
|
|
If the script fails, the package is marked as unpacked and the script is
|
|
executed when the image boots again.
|
|
</para>
|
|
|
|
<para>
|
|
Sometimes it is necessary for the execution of a post-installation
|
|
script to be delayed until the first boot.
|
|
For example, the script might need to be executed on the device itself.
|
|
To delay script execution until boot time, use the following structure in the
|
|
post-installation script:
|
|
<literallayout class='monospaced'>
|
|
pkg_postinst_PACKAGENAME () {
|
|
#!/bin/sh -e
|
|
if [ x"$D" = "x" ]; then
|
|
# Actions to carry out on the device go here
|
|
else
|
|
exit 1
|
|
fi
|
|
}
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
The previous example delays execution until the image boots again because the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'>D</ulink></filename>
|
|
variable points
|
|
to the directory containing the image when the root filesystem is created at build time but
|
|
is unset when executed on the first boot.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-customimage'>
|
|
<title>Customizing Images</title>
|
|
|
|
<para>
|
|
You can customize Yocto Project images to satisfy particular requirements.
|
|
This section describes several methods and provides guidelines for each.
|
|
</para>
|
|
|
|
<section id='usingpoky-extend-customimage-custombb'>
|
|
<title>Customizing Images Using Custom .bb Files</title>
|
|
|
|
<para>
|
|
One way to get additional software into an image is to create a custom image.
|
|
The following example shows the form for the two lines you need:
|
|
<literallayout class='monospaced'>
|
|
IMAGE_INSTALL = "task-core-x11-base package1 package2"
|
|
|
|
inherit core-image
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
By creating a custom image, a developer has total control
|
|
over the contents of the image.
|
|
It is important to use the correct names of packages in the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>
|
|
variable.
|
|
You must use the OpenEmbedded notation and not the Debian notation for the names
|
|
(e.g. <filename>eglibc-dev</filename> instead of <filename>libc6-dev</filename>).
|
|
</para>
|
|
|
|
<para>
|
|
The other method for creating a custom image is to modify an existing image.
|
|
For example, if a developer wants to add <filename>strace</filename> into
|
|
the <filename>core-image-sato</filename> image, they can use the following recipe:
|
|
<literallayout class='monospaced'>
|
|
require core-image-sato.bb
|
|
|
|
IMAGE_INSTALL += "strace"
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-customimage-customtasks'>
|
|
<title>Customizing Images Using Custom Tasks</title>
|
|
|
|
<para>
|
|
For complex custom images, the best approach is to create a custom task package
|
|
that is used to build the image or images.
|
|
A good example of a tasks package is
|
|
<filename>meta/recipes-sato/tasks/task-poky.bb</filename>.
|
|
The
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'>PACKAGES</ulink></filename>
|
|
variable lists the task packages to build along with the complementary
|
|
<filename>-dbg</filename> and <filename>-dev</filename> packages.
|
|
For each package added, you can use
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'>RDEPENDS</ulink></filename>
|
|
and
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'>RRECOMMENDS</ulink></filename>
|
|
entries to provide a list of packages the parent task package should contain.
|
|
Following is an example:
|
|
<literallayout class='monospaced'>
|
|
DESCRIPTION = "My Custom Tasks"
|
|
|
|
PACKAGES = "\
|
|
task-custom-apps \
|
|
task-custom-apps-dbg \
|
|
task-custom-apps-dev \
|
|
task-custom-tools \
|
|
task-custom-tools-dbg \
|
|
task-custom-tools-dev \
|
|
"
|
|
|
|
RDEPENDS_task-custom-apps = "\
|
|
dropbear \
|
|
portmap \
|
|
psplash"
|
|
|
|
RDEPENDS_task-custom-tools = "\
|
|
oprofile \
|
|
oprofileui-server \
|
|
lttng-control \
|
|
lttng-viewer"
|
|
|
|
RRECOMMENDS_task-custom-tools = "\
|
|
kernel-module-oprofile"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
In the previous example, two task packages are created with their dependencies and their
|
|
recommended package dependencies listed: <filename>task-custom-apps</filename>, and
|
|
<filename>task-custom-tools</filename>.
|
|
To build an image using these task packages, you need to add
|
|
<filename>task-custom-apps</filename> and/or
|
|
<filename>task-custom-tools</filename> to
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>.
|
|
For other forms of image dependencies see the other areas of this section.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-customimage-imagefeatures'>
|
|
<title>Customizing Images Using Custom <filename>IMAGE_FEATURES</filename> and
|
|
<filename>EXTRA_IMAGE_FEATURES</filename></title>
|
|
|
|
<para>
|
|
Ultimately users might want to add extra image features to the set used by
|
|
Yocto Project with the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'>IMAGE_FEATURES</ulink></filename>
|
|
variable.
|
|
To create these features, the best reference is
|
|
<filename>meta/classes/core-image.bbclass</filename>, which shows how the
|
|
Yocto Project achieves this.
|
|
In summary, the file looks at the contents of the
|
|
<filename>IMAGE_FEATURES</filename>
|
|
variable and then maps that into a set of tasks or packages.
|
|
Based on this information the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'> IMAGE_INSTALL</ulink></filename>
|
|
variable is generated automatically.
|
|
Users can add extra features by extending the class or creating a custom class for use
|
|
with specialized image <filename>.bb</filename> files.
|
|
You can also add more features by configuring the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'>EXTRA_IMAGE_FEATURES</ulink></filename>
|
|
variable in the <filename>local.conf</filename> file found in the Yocto Project
|
|
files located in the build directory.
|
|
</para>
|
|
|
|
<para>
|
|
The Yocto Project ships with two SSH servers you can use in your images:
|
|
Dropbear and OpenSSH.
|
|
Dropbear is a minimal SSH server appropriate for resource-constrained environments,
|
|
while OpenSSH is a well-known standard SSH server implementation.
|
|
By default, the <filename>core-image-sato</filename> image is configured to use Dropbear.
|
|
The <filename>core-image-basic</filename> and <filename>core-image-lsb</filename>
|
|
images both include OpenSSH.
|
|
To change these defaults, edit the <filename>IMAGE_FEATURES</filename> variable
|
|
so that it sets the image you are working with to include
|
|
<filename>ssh-server-dropbear</filename> or <filename>ssh-server-openssh</filename>.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='usingpoky-extend-customimage-localconf'>
|
|
<title>Customizing Images Using <filename>local.conf</filename></title>
|
|
|
|
<para>
|
|
It is possible to customize image contents by using variables from your
|
|
local configuration in your <filename>conf/local.conf</filename> file.
|
|
Because it is limited to local use, this method generally only allows you to
|
|
add packages and is not as flexible as creating your own customized image.
|
|
When you add packages using local variables this way, you need to realize that
|
|
these variable changes affect all images at the same time and might not be
|
|
what you require.
|
|
</para>
|
|
|
|
<section id='adding-packages'>
|
|
<title>Adding Packages</title>
|
|
|
|
<para>
|
|
The simplest way to add extra packages to all images is by using the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>
|
|
variable with the <filename>_append</filename> operator:
|
|
<literallayout class='monospaced'>
|
|
IMAGE_INSTALL_append = " strace"
|
|
</literallayout>
|
|
Use of the syntax is important.
|
|
Specifically, the space between the quote and the package name, which is
|
|
<filename>strace</filename> in this example.
|
|
This space is required since the <filename>_append</filename>
|
|
operator does not add the space.
|
|
</para>
|
|
|
|
<para>
|
|
Furthermore, you must use <filename>_append</filename> instead of the <filename>+=</filename>
|
|
operator if you want to avoid ordering issues.
|
|
The reason for this is because doing so unconditionally appends to the variable and
|
|
avoids ordering problems due to the variable being set in image recipes and
|
|
<filename>.bbclass</filename> files with operators like <filename>?=</filename>.
|
|
Using <filename>_append</filename> ensures the operation takes affect.
|
|
</para>
|
|
|
|
<para>
|
|
As shown in its simplest use, <filename>IMAGE_INSTALL_append</filename> affects
|
|
all images.
|
|
It is possible to extend the syntax so that the variable applies to a specific image only.
|
|
Here is an example:
|
|
<literallayout class='monospaced'>
|
|
IMAGE_INSTALL_append_pn-core-image-minimal = " strace"
|
|
</literallayout>
|
|
This example adds <filename>strace</filename> to <filename>core-image-minimal</filename>
|
|
only.
|
|
</para>
|
|
|
|
<para>
|
|
You can add packages using a similar approach through the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-POKY_EXTRA_INSTALL'>POKY_EXTRA_INSTALL</ulink></filename>
|
|
variable.
|
|
If you use this variable, only <filename>core-image-*</filename> images are affected.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='excluding-packages'>
|
|
<title>Excluding Packages</title>
|
|
|
|
<para>
|
|
It is possible to filter or mask out <filename>.bb</filename> and
|
|
<filename>.bbappend</filename> files such that BitBake ignores them during
|
|
the build.
|
|
You can do this by providing an expression with the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBMASK'>BBMASK</ulink></filename>
|
|
variable.
|
|
Here is an example:
|
|
<literallayout class='monospaced'>
|
|
BBMASK = ".*/meta-mymachine/recipes-maybe/"
|
|
</literallayout>
|
|
Here, all <filename>.bb</filename> and <filename>.bbappend</filename> files
|
|
in the directory that matches the expression are ignored during the build
|
|
process.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="platdev-newmachine">
|
|
<title>Porting the Yocto Project to a New Machine</title>
|
|
|
|
<!--
|
|
WRITER NOTES:
|
|
|
|
I had this chat with Richard:
|
|
|
|
scottrif: Terminology question: We speak of "New Machines" or "Adding a New Machine"
|
|
in YP. Are "Machines" restricted to architectures? In poky/meta/conf/machine we have .conf
|
|
files for the five architectures. What exactly does the term "Machine" mean?
|
|
|
|
RP: no, each architecture has multiple different machines. A "machine" can correspond
|
|
to a particular reference board or hardware product
|
|
we just have one reference machine per architecture
|
|
We're a little vague sometimes as "machine" can refer to either an individual platform,
|
|
or in some cases a set of different platforms with common structure
|
|
(e.g. netbooks)
|
|
|
|
scottrif: So our reference machines we supply are the five qemu* machines?
|
|
|
|
RP: in oe-core, plus one "real" target in meta-yocto
|
|
(per arch)
|
|
|
|
scottrif: I see four in meta-yocto/conf/machine. Shouldn't there be five if there is one
|
|
"real" target per architecture?
|
|
|
|
RP: yes, we don't have one for x86_64 :/
|
|
|
|
scottrif: I think it is a bit difficult to map our four poky/meta-yocto/conf/machines to one of our
|
|
five architectures. Some have key words in there that identify the architecture but
|
|
beagleboard and atom-pc don't.
|
|
We have a section that describes adding a Machine Configuration file to Yocto and
|
|
it states that TARGET_ARCH is one of the most important variables that need to be
|
|
set in the .conf file. The four I am looking at don't have that variable.
|
|
|
|
RP: That has changed a little now. You need to include the appropriate tune file
|
|
which will set it for you
|
|
People had a tendency not to set all the right pieces so it got abstracted
|
|
|
|
scottrif: Got it. I see them in poky/meta/conf/machine/include.
|
|
|
|
SOME CONCLUSIONS:
|
|
|
|
I need to define the term machine. It is confusing. Then, this section needs to be cleared up
|
|
so that there are some definite steps on how to do this. I need more detail here.
|
|
|
|
-->
|
|
|
|
<para>
|
|
Adding a new machine to the Yocto Project is a straightforward process.
|
|
This section provides information that gives you an idea of the changes you must make.
|
|
The information covers adding machines similar to those the Yocto Project already supports.
|
|
Although well within the capabilities of the Yocto Project, adding a totally new architecture
|
|
might require
|
|
changes to <filename>gcc/eglibc</filename> and to the site information, which is
|
|
beyond the scope of this manual.
|
|
</para>
|
|
|
|
<para>
|
|
For a complete example that shows how to add a new machine to the Yocto Project,
|
|
see the
|
|
"<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-bsp-appendix'>BSP Development Example</ulink>"
|
|
in Appendix A.
|
|
</para>
|
|
|
|
<section id="platdev-newmachine-conffile">
|
|
<title>Adding the Machine Configuration File</title>
|
|
|
|
<para>
|
|
To add a machine configuration you need to add a <filename>.conf</filename> file
|
|
with details of the device being added to the <filename>conf/machine/</filename> file.
|
|
The name of the file determines the name the Yocto Project uses to reference the new machine.
|
|
</para>
|
|
|
|
<para>
|
|
The most important variables to set in this file are as follows:
|
|
<itemizedlist>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-TARGET_ARCH'>
|
|
TARGET_ARCH</ulink></filename> (e.g. "arm")</para></listitem>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PREFERRED_PROVIDER'>
|
|
PREFERRED_PROVIDER</ulink></filename>_virtual/kernel (see below)</para></listitem>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_FEATURES'>
|
|
MACHINE_FEATURES</ulink></filename> (e.g. "kernel26 apm screen wifi")</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
You might also need these variables:
|
|
<itemizedlist>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SERIAL_CONSOLE'>
|
|
SERIAL_CONSOLE</ulink></filename> (e.g. "115200 ttyS0")</para></listitem>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_IMAGETYPE'>
|
|
KERNEL_IMAGETYPE</ulink></filename> (e.g. "zImage")</para></listitem>
|
|
<listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FSTYPES'>
|
|
IMAGE_FSTYPES</ulink></filename> (e.g. "tar.gz jffs2")</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
You can find full details on these variables in the reference section.
|
|
You can leverage many existing machine <filename>.conf</filename> files from
|
|
<filename>meta/conf/machine/</filename>.
|
|
</para>
|
|
</section>
|
|
|
|
<section id="platdev-newmachine-kernel">
|
|
<title>Adding a Kernel for the Machine</title>
|
|
|
|
<para>
|
|
The Yocto Project needs to be able to build a kernel for the machine.
|
|
You need to either create a new kernel recipe for this machine, or extend an
|
|
existing recipe.
|
|
You can find several kernel examples in the
|
|
Yocto Project file's <filename>meta/recipes-kernel/linux</filename>
|
|
directory that you can use as references.
|
|
</para>
|
|
|
|
<para>
|
|
If you are creating a new recipe, normal recipe-writing rules apply for setting
|
|
up a
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>.
|
|
Thus, you need to specify any necessary patches and set
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename> to point at the source code.
|
|
You need to create a <filename>configure</filename> task that configures the
|
|
unpacked kernel with a defconfig.
|
|
You can do this by using a <filename>make defconfig</filename> command or,
|
|
more commonly, by copying in a suitable <filename>defconfig</filename> file and and then running
|
|
<filename>make oldconfig</filename>.
|
|
By making use of <filename>inherit kernel</filename> and potentially some of the
|
|
<filename>linux-*.inc</filename> files, most other functionality is
|
|
centralized and the the defaults of the class normally work well.
|
|
</para>
|
|
|
|
<para>
|
|
If you are extending an existing kernel, it is usually a matter of adding a
|
|
suitable defconfig file.
|
|
The file needs to be added into a location similar to defconfig files
|
|
used for other machines in a given kernel.
|
|
A possible way to do this is by listing the file in the
|
|
<filename>SRC_URI</filename> and adding the machine to the expression in
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-COMPATIBLE_MACHINE'>COMPATIBLE_MACHINE</ulink></filename>:
|
|
<literallayout class='monospaced'>
|
|
COMPATIBLE_MACHINE = '(qemux86|qemumips)'
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id="platdev-newmachine-formfactor">
|
|
<title>Adding a Formfactor Configuration File</title>
|
|
|
|
<para>
|
|
A formfactor configuration file provides information about the
|
|
target hardware for which the Yocto Project is building and information that
|
|
the Yocto Project cannot obtain from other sources such as the kernel.
|
|
Some examples of information contained in a formfactor configuration file include
|
|
framebuffer orientation, whether or not the system has a keyboard,
|
|
the positioning of the keyboard in relation to the screen, and
|
|
the screen resolution.
|
|
</para>
|
|
|
|
<para>
|
|
The Yocto Project uses reasonable defaults in most cases, but if customization is
|
|
necessary you need to create a <filename>machconfig</filename> file
|
|
in the Yocto Project file's <filename>meta/recipes-bsp/formfactor/files</filename>
|
|
directory.
|
|
This directory contains directories for specific machines such as
|
|
<filename>qemuarm</filename> and <filename>qemux86</filename>.
|
|
For information about the settings available and the defaults, see the
|
|
<filename>meta/recipes-bsp/formfactor/files/config</filename> file found in the
|
|
same area.
|
|
Following is an example for qemuarm:
|
|
<literallayout class='monospaced'>
|
|
HAVE_TOUCHSCREEN=1
|
|
HAVE_KEYBOARD=1
|
|
|
|
DISPLAY_CAN_ROTATE=0
|
|
DISPLAY_ORIENTATION=0
|
|
#DISPLAY_WIDTH_PIXELS=640
|
|
#DISPLAY_HEIGHT_PIXELS=480
|
|
#DISPLAY_BPP=16
|
|
DISPLAY_DPI=150
|
|
DISPLAY_SUBPIXEL_ORDER=vrgb
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="modifying-temporary-source-code">
|
|
<title>Modifying Temporary Source Code</title>
|
|
|
|
<para>
|
|
Although the Yocto Project is typically used to build software, you might
|
|
find it helpful during development to modify the temporary source code used by recipes
|
|
to build packages.
|
|
For example, suppose you are developing a patch and you need to experiment a bit
|
|
to figure out your solution.
|
|
After you have initially built the package, you can iteratively tweak the
|
|
source code, which is located in the
|
|
<link linkend='yocto-project-build-directory'>Yocto Project's Build Directory</link>, and then
|
|
you can force a re-compile and quickly test your altered code.
|
|
Once you settle on a solution, you can then preserve your changes in the form of
|
|
patches.
|
|
You can accomplish these steps all within either a
|
|
<ulink url='http://savannah.nongnu.org/projects/quilt'>Quilt</ulink> or
|
|
<link linkend='git'>Git</link> workflow.
|
|
</para>
|
|
|
|
<section id='finding-the-temporary-source-code'>
|
|
<title>Finding the Temporary Source Code</title>
|
|
|
|
<para>
|
|
During a build, the unpacked temporary source code used by recipes
|
|
to build packages is available in the Yocto Project Build Directory as
|
|
defined by the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename> variable.
|
|
Below is the default value for the <filename>S</filename> variable as defined in the
|
|
<filename>meta/conf/bitbake.conf</filename> configuration file in the
|
|
<link linkend='yocto-project-files'>Yocto Project Files</link>:
|
|
<literallayout class='monospaced'>
|
|
S = ${WORKDIR}/${BP}
|
|
</literallayout>
|
|
You should be aware that many recipes override the <filename>S</filename> variable.
|
|
For example, recipes that fetch their source from Git usually set
|
|
<filename>S</filename> to <filename>${WORKDIR}/git</filename>.
|
|
<note>
|
|
<filename>BP</filename> represents the "Base Package", which is the base package
|
|
name and the package version:
|
|
<literallayout class='monospaced'>
|
|
BP = ${BPN}-${PV}
|
|
</literallayout>
|
|
</note>
|
|
</para>
|
|
|
|
<para>
|
|
The path to the work directory for the recipe
|
|
(<ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>) depends
|
|
on the package name and the architecture of the target device.
|
|
For example, here is the work directory for packages whose targets are not device-dependent:
|
|
<literallayout class='monospaced'>
|
|
${TMPDIR}/work/${PACKAGE_ARCH}-poky-${TARGET_OS}/${PN}-${PV}-${PR}
|
|
</literallayout>
|
|
Let's look at an example without variables.
|
|
Assuming a Yocto Project Files top-level directory named <filename>poky</filename>
|
|
and a default Yocto Project Build Directory of <filename>poky/build</filename>,
|
|
the following is the work directory for the <filename>acl</filename> package:
|
|
<literallayout class='monospaced'>
|
|
~/poky/build/tmp/work/i586-poky-linux/acl-2.2.51-r3
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
If your package is dependent on the target device, the work directory varies slightly:
|
|
<literallayout class='monospaced'>
|
|
${TMPDIR}/work/${MACHINE}-poky-${TARGET_OS}/${PN}-${PV}-${PR}
|
|
</literallayout>
|
|
Again, assuming a Yocto Project Files top-level directory named <filename>poky</filename>
|
|
and a default Yocto Project Build Directory of <filename>poky/build</filename>, the
|
|
following is the work directory for the <filename>acl</filename> package that is being
|
|
built for a MIPS-based device:
|
|
<literallayout class='monospaced'>
|
|
~/poky/build/tmp/work/mips-poky-linux/acl-2.2.51-r2
|
|
</literallayout>
|
|
</para>
|
|
|
|
<note>
|
|
To better understand how the Yocto Project build system resolves directories during the
|
|
build process, see the glossary entries for the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-TOPDIR'><filename>TOPDIR</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ARCH'><filename>PACKAGE_ARCH</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-TARGET_OS'><filename>TARGET_OS</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>,
|
|
and
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
|
|
variables in the Yocto Project Reference Manual.
|
|
</note>
|
|
|
|
<para>
|
|
Now that you know where to locate the directory that has the temporary source code, you can use a
|
|
Quilt or Git workflow to make your edits, test the changes, and preserve the
|
|
changes in the form of patches.
|
|
</para>
|
|
</section>
|
|
|
|
<section id="using-a-quilt-workflow">
|
|
<title>Using a Quilt Workflow</title>
|
|
|
|
<para>
|
|
<ulink url='http://savannah.nongnu.org/projects/quilt'>Quilt</ulink>
|
|
is a powerful tool that allows you to capture source code changes without having
|
|
a clean source tree.
|
|
This section outlines the typical workflow you can use to modify temporary source code,
|
|
test changes, and then preserve the changes in the form of a patch all using Quilt.
|
|
</para>
|
|
|
|
<para>
|
|
Follow these general steps:
|
|
<orderedlist>
|
|
<listitem><para><emphasis>Find the Source Code:</emphasis>
|
|
The temporary source code used by the Yocto Project build system is kept in the
|
|
Yocto Project Build Directory.
|
|
See the
|
|
"<link linkend='finding-the-temporary-source-code'>Finding the Temporary Source Code</link>"
|
|
section to learn how to locate the directory that has the temporary source code for a
|
|
particular package.</para></listitem>
|
|
<listitem><para><emphasis>Change Your Working Directory:</emphasis>
|
|
You need to be in the directory that has the temporary source code.
|
|
That directory is defined by the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink>
|
|
variable.</para></listitem>
|
|
<listitem><para><emphasis>Create a New Patch:</emphasis>
|
|
Before modifying source code, you need to create a new patch.
|
|
To create a new patch file, use <filename>quilt new</filename> as below:
|
|
<literallayout class='monospaced'>
|
|
$ quilt new my_changes.patch
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Notify Quilt and Add Files:</emphasis>
|
|
After creating the patch, you need to notify Quilt about the files you will
|
|
be changing.
|
|
Add the files you will be modifying into the patch you just created:
|
|
<literallayout class='monospaced'>
|
|
$ quilt add file1.c file2.c file3.c
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Edit the Files:</emphasis>
|
|
Make the changes to the temporary source code.</para></listitem>
|
|
<listitem><para><emphasis>Test Your Changes:</emphasis>
|
|
Once you have modified the source code, the easiest way to test your changes
|
|
is by calling the <filename>compile</filename> task as shown in the following example:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -c compile -f <name_of_package>
|
|
</literallayout>
|
|
The <filename>-f</filename> or <filename>--force</filename>
|
|
option forces re-execution of the specified task.
|
|
If you find problems with your code, you can just keep editing and
|
|
re-testing iteratively until things work as expected.
|
|
<note>All the modifications you make to the temporary source code
|
|
disappear once you <filename>-c clean</filename> or
|
|
<filename>-c cleanall</filename> with BitBake for the package.
|
|
Modifications will also disappear if you use the <filename>rm_work</filename>
|
|
feature as described in the
|
|
"<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>"
|
|
section of the Yocto Project Quick Start.
|
|
</note></para></listitem>
|
|
<listitem><para><emphasis>Generate the Patch:</emphasis>
|
|
Once your changes work as expected, you need to use Quilt to generate the final patch that
|
|
contains all your modifications.
|
|
<literallayout class='monospaced'>
|
|
$ quilt refresh
|
|
</literallayout>
|
|
At this point the <filename>my_changes.patch</filename> file has all your edits made
|
|
to the <filename>file1.c</filename>, <filename>file2.c</filename>, and
|
|
<filename>file3.c</filename> files.</para>
|
|
<para>You can find the resulting patch file in the <filename>patches/</filename>
|
|
subdirectory of the source (<filename>S</filename>) directory.</para></listitem>
|
|
<listitem><para><emphasis>Copy the Patch File:</emphasis>
|
|
For simplicity, copy the patch file into a directory named <filename>files</filename>,
|
|
which you can create in the same directory as the recipe.
|
|
Placing the patch here guarantees that the Yocto Project build system will find
|
|
the patch.
|
|
Next, add the patch into the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>
|
|
of the recipe.
|
|
Here is an example:
|
|
<literallayout class='monospaced'>
|
|
SRC_URI += "file://my_changes.patch"
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Increment the Package Revision Number:</emphasis>
|
|
Finally, don't forget to 'bump' the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PR'>PR</ulink></filename>
|
|
value in the same recipe since the resulting packages have changed.</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='using-a-git-workflow'>
|
|
<title>Using a Git Workflow</title>
|
|
<para>
|
|
Git is an even more powerful tool that allows you to capture source code changes without having
|
|
a clean source tree.
|
|
This section outlines the typical workflow you can use to modify temporary source code,
|
|
test changes, and then preserve the changes in the form of a patch all using Git.
|
|
For general information on Git as it is used in the Yocto Project, see the
|
|
"<link linkend='git'>Git</link>" section.
|
|
</para>
|
|
|
|
<note>
|
|
This workflow uses Git only for its ability to manage local changes to the source code
|
|
and produce patches independent of any version control used on the Yocto Project
|
|
Files.
|
|
</note>
|
|
|
|
<para>
|
|
Follow these general steps:
|
|
<orderedlist>
|
|
<listitem><para><emphasis>Find the Source Code:</emphasis>
|
|
The temporary source code used by the Yocto Project build system is kept in the
|
|
Yocto Project Build Directory.
|
|
See the
|
|
"<link linkend='finding-the-temporary-source-code'>Finding the Temporary Source Code</link>"
|
|
section to learn how to locate the directory that has the temporary source code for a
|
|
particular package.</para></listitem>
|
|
<listitem><para><emphasis>Change Your Working Directory:</emphasis>
|
|
You need to be in the directory that has the temporary source code.
|
|
That directory is defined by the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink>
|
|
variable.</para></listitem>
|
|
<listitem><para><emphasis>Initialize a Git Repository:</emphasis>
|
|
Use the <filename>git init</filename> command to initialize a new local repository
|
|
that is based on the work directory:
|
|
<literallayout class='monospaced'>
|
|
$ git init
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Stage all the files:</emphasis>
|
|
Use the <filename>git add *</filename> command to stage all the files in the source
|
|
code directory so that they can be committed:
|
|
<literallayout class='monospaced'>
|
|
$ git add *
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Commit the Source Files:</emphasis>
|
|
Use the <filename>git commit</filename> command to initially commit all the files in
|
|
the work directory:
|
|
<literallayout class='monospaced'>
|
|
$ git commit
|
|
</literallayout>
|
|
At this point, your Git repository is aware of all the source code files.
|
|
Any edits you now make to files will be tracked by Git.</para></listitem>
|
|
<listitem><para><emphasis>Edit the Files:</emphasis>
|
|
Make the changes to the temporary source code.</para></listitem>
|
|
<listitem><para><emphasis>Test Your Changes:</emphasis>
|
|
Once you have modified the source code, the easiest way to test your changes
|
|
is by calling the <filename>compile</filename> task as shown in the following example:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake -c compile -f <name_of_package>
|
|
</literallayout>
|
|
The <filename>-f</filename> or <filename>--force</filename>
|
|
option forces re-execution of the specified task.
|
|
If you find problems with your code, you can just keep editing and
|
|
re-testing iteratively until things work as expected.
|
|
<note>All the modifications you make to the temporary source code
|
|
disappear once you <filename>-c clean</filename> or
|
|
<filename>-c cleanall</filename> with BitBake for the package.
|
|
Modifications will also disappear if you use the <filename>rm_work</filename>
|
|
feature as described in the
|
|
"<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>"
|
|
section of the Yocto Project Quick Start.
|
|
</note></para></listitem>
|
|
<listitem><para><emphasis>See the List of Files You Changed:</emphasis>
|
|
Use the <filename>git status</filename> command to see what files you have actually edited.
|
|
The ability to have Git track the files you have changed is an advantage that this
|
|
workflow has over the Quilt workflow.
|
|
Here is the Git command to list your changed files:
|
|
<literallayout class='monospaced'>
|
|
$ git status
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Stage the Modified Files:</emphasis>
|
|
Use the <filename>git add</filename> command to stage the changed files so they
|
|
can be committed as follows:
|
|
<literallayout class='monospaced'>
|
|
$ git add file1.c file2.c file3.c
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Commit the Staged Files and View Your Changes:</emphasis>
|
|
Use the <filename>git commit</filename> command to commit the changes to the
|
|
local repository.
|
|
Once you have committed the files, you can use the <filename>git log</filename>
|
|
command to see your changes:
|
|
<literallayout class='monospaced'>
|
|
$ git commit
|
|
$ git log
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Generate the Patch:</emphasis>
|
|
Once the changes are committed, use the <filename>git format-patch</filename>
|
|
command to generate a patch file:
|
|
<literallayout class='monospaced'>
|
|
$ git format-patch HEAD~1
|
|
</literallayout>
|
|
The <filename>HEAD~1</filename> part of the command causes Git to generate the
|
|
patch file for the most recent commit.</para>
|
|
<para>At this point, the patch file has all your edits made
|
|
to the <filename>file1.c</filename>, <filename>file2.c</filename>, and
|
|
<filename>file3.c</filename> files.
|
|
You can find the resulting patch file in the current directory.
|
|
The patch file ends with <filename>.patch</filename>.</para></listitem>
|
|
<listitem><para><emphasis>Copy the Patch File:</emphasis>
|
|
For simplicity, copy the patch file into a directory named <filename>files</filename>,
|
|
which you can create in the same directory as the recipe.
|
|
Placing the patch here guarantees that the Yocto Project build system will find
|
|
the patch.
|
|
Next, add the patch into the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>
|
|
of the recipe.
|
|
Here is an example:
|
|
<literallayout class='monospaced'>
|
|
SRC_URI += "file://my_changes.patch"
|
|
</literallayout></para></listitem>
|
|
<listitem><para><emphasis>Increment the Package Revision Number:</emphasis>
|
|
Finally, don't forget to 'bump' the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PR'>PR</ulink></filename>
|
|
value in the same recipe since the resulting packages have changed.</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="building-multiple-architecture-libraries-into-one-image">
|
|
<title>Combining Multiple Versions of Library Files into One Image</title>
|
|
|
|
<para>
|
|
The build system offers the ability to build libraries with different
|
|
target optimizations or architecture formats and combine these together
|
|
into one system image.
|
|
You can link different binaries in the image
|
|
against the different libraries as needed for specific use cases.
|
|
This feature is called "Multilib."
|
|
</para>
|
|
|
|
<para>
|
|
An example would be where you have most of a system compiled in 32-bit
|
|
mode using 32-bit libraries, but you have something large, like a database
|
|
engine, that needs to be a 64-bit application and use 64-bit libraries.
|
|
Multilib allows you to get the best of both 32-bit and 64-bit libraries.
|
|
</para>
|
|
|
|
<para>
|
|
While the Multilib feature is most commonly used for 32 and 64-bit differences,
|
|
the approach the build system uses facilitates different target optimizations.
|
|
You could compile some binaries to use one set of libraries and other binaries
|
|
to use other different sets of libraries.
|
|
The libraries could differ in architecture, compiler options, or other
|
|
optimizations.
|
|
</para>
|
|
|
|
<para>
|
|
This section overviews the Multilib process only.
|
|
For more details on how to implement Multilib, see the
|
|
<ulink url='&YOCTO_WIKI_URL;/wiki/Multilib'>Multilib</ulink> wiki
|
|
page.
|
|
</para>
|
|
|
|
<section id='preparing-to-use-multilib'>
|
|
<title>Preparing to use Multilib</title>
|
|
|
|
<para>
|
|
User-specific requirements drive the Multilib feature,
|
|
Consequently, there is no one "out-of-the-box" configuration that likely
|
|
exists to meet your needs.
|
|
</para>
|
|
|
|
<para>
|
|
In order to enable Multilib, you first need to ensure your recipe is
|
|
extended to support multiple libraries.
|
|
Many standard recipes are already extended and support multiple libraries.
|
|
You can check in the <filename>meta/conf/multilib.conf</filename>
|
|
configuration file in the Yocto Project files directory to see how this is
|
|
done using the <filename>BBCLASSEXTEND</filename> variable.
|
|
Eventually, all recipes will be covered and this list will be unneeded.
|
|
</para>
|
|
|
|
<para>
|
|
For the most part, the Multilib class extension works automatically to
|
|
extend the package name from <filename>${PN}</filename> to
|
|
<filename>${MLPREFIX}${PN}</filename>, where <filename>MLPREFIX</filename>
|
|
is the particular multilib (e.g. "lib32-" or "lib64-").
|
|
Standard variables such as <filename>DEPENDS</filename>,
|
|
<filename>RDEPENDS</filename>, <filename>RPROVIDES</filename>,
|
|
<filename>RRECOMMENDS</filename>, <filename>PACKAGES</filename>, and
|
|
<filename>PACKAGES_DYNAMIC</filename> are automatically extended by the system.
|
|
If you are extending any manual code in the recipe, you can use the
|
|
<filename>${MLPREFIX}</filename> variable to ensure those names are extended
|
|
correctly.
|
|
This automatic extension code resides in <filename>multilib.bbclass</filename>.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='using-multilib'>
|
|
<title>Using Multilib</title>
|
|
|
|
<para>
|
|
After you have set up the recipes, you need to define the actual
|
|
combination of multiple libraries you want to build.
|
|
You accomplish this through your <filename>local.conf</filename>
|
|
configuration file in the
|
|
<link linkend='yocto-project-build-directory'>Yocto Project Build Directory</link>.
|
|
An example configuration would be as follows:
|
|
<literallayout class='monospaced'>
|
|
MACHINE = "qemux86-64"
|
|
require conf/multilib.conf
|
|
MULTILIBS = "multilib:lib32"
|
|
DEFAULTTUNE_virtclass-multilib-lib32 = "x86"
|
|
MULTILIB_IMAGE_INSTALL = "lib32-connman"
|
|
</literallayout>
|
|
This example enables an
|
|
additional library named <filename>lib32</filename> alongside the
|
|
normal target packages.
|
|
When combining these "lib32" alternatives, the example uses "x86" for tuning.
|
|
For information on this particular tuning, see
|
|
<filename>meta/conf/machine/include/ia32/arch-ia32.inc</filename>.
|
|
</para>
|
|
|
|
<para>
|
|
The example then includes <filename>lib32-connman</filename>
|
|
in all the images, which illustrates one method of including a
|
|
multiple library dependency.
|
|
You can use a normal image build to include this dependency,
|
|
for example:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake core-image-sato
|
|
</literallayout>
|
|
You can also build Multilib packages specifically with a command like this:
|
|
<literallayout class='monospaced'>
|
|
$ bitbake lib32-connman
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='additional-implementation-details'>
|
|
<title>Additional Implementation Details</title>
|
|
|
|
<para>
|
|
Different packaging systems have different levels of native Multilib
|
|
support.
|
|
For the RPM Package Management System, the following implementation details
|
|
exist:
|
|
<itemizedlist>
|
|
<listitem><para>A unique architecture is defined for the Multilib packages,
|
|
along with creating a unique deploy folder under
|
|
<filename>tmp/deploy/rpm</filename> in the
|
|
<link linkend='yocto-project-build-directory'>Yocto Project Build Directory</link>.
|
|
For example, consider <filename>lib32</filename> in a
|
|
<filename>qemux86-64</filename> image.
|
|
The possible architectures in the system are "all", "qemux86_64",
|
|
"lib32_qemux86_64", and "lib32_x86".</para></listitem>
|
|
<listitem><para>The <filename>${MLPREFIX}</filename> variable is stripped from
|
|
<filename>${PN}</filename> during RPM packaging.
|
|
The naming for a normal RPM package and a Multilib RPM package in a
|
|
<filename>qemux86-64</filename> system resolves to something similar to
|
|
<filename>bash-4.1-r2.x86_64.rpm</filename> and
|
|
<filename>bash-4.1.r2.lib32_x86.rpm</filename>, respectively.
|
|
</para></listitem>
|
|
<listitem><para>When installing a Multilib image, the RPM backend first
|
|
installs the base image and then installs the Multilib libraries.
|
|
</para></listitem>
|
|
<listitem><para>The build system relies on RPM to resolve the identical files in the
|
|
two (or more) Multilib packages.</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
For the IPK Package Management System, the following implementation details exist:
|
|
<itemizedlist>
|
|
<listitem><para>The <filename>${MLPREFIX}</filename> is not stripped from
|
|
<filename>${PN}</filename> during IPK packaging.
|
|
The naming for a normal RPM package and a Multilib IPK package in a
|
|
<filename>qemux86-64</filename> system resolves to something like
|
|
<filename>bash_4.1-r2.x86_64.ipk</filename> and
|
|
<filename>lib32-bash_4.1-rw_x86.ipk</filename>, respectively.
|
|
</para></listitem>
|
|
<listitem><para>The IPK deploy folder is not modified with
|
|
<filename>${MLPREFIX}</filename> because packages with and without
|
|
the Multilib feature can exist in the same folder due to the
|
|
<filename>${PN}</filename> differences.</para></listitem>
|
|
<listitem><para>IPK defines a sanity check for Multilib installation
|
|
using certain rules for file comparison, overridden, etc.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id='configuring-the-kernel'>
|
|
<title>Configuring the Kernel</title>
|
|
|
|
<para>
|
|
Configuring the Linux Yocto kernel consists of making sure the <filename>.config</filename>
|
|
file has all the right information in it for the image you are building.
|
|
You can use the <filename>menuconfig</filename> tool and configuration fragments to
|
|
make sure your <filename>.config</filename> file is just how you need it.
|
|
This section describes how to use <filename>menuconfig</filename>, create and use
|
|
configuration fragments, and how to interactively tweak your <filename>.config</filename>
|
|
file to create the leanest kernel configuration file possible.
|
|
</para>
|
|
|
|
<para>
|
|
For concepts on kernel configuration, see the
|
|
"<ulink url='&YOCTO_DOCS_KERNEL_URL;#kernel-configuration'>Kernel Configuration</ulink>"
|
|
section in the Yocto Project Kernel Architecture and Use Manual.
|
|
</para>
|
|
|
|
<section id='using-menuconfig'>
|
|
<title>Using <filename>menuconfig</filename></title>
|
|
|
|
<para>
|
|
The easiest way to define kernel configurations is to set them through the
|
|
<filename>menuconfig</filename> tool.
|
|
For general information on <filename>menuconfig</filename>, see
|
|
<ulink url='http://en.wikipedia.org/wiki/Menuconfig'></ulink>.
|
|
</para>
|
|
|
|
<para>
|
|
To use the <filename>menuconfig</filename> tool in the Yocto Project development
|
|
environment, you must build the tool using BitBake.
|
|
The following commands build and invoke <filename>menuconfig</filename> assuming the
|
|
Yocto Project files top-level directory is <filename>~/poky</filename>:
|
|
<literallayout class='monospaced'>
|
|
$ cd ~/poky
|
|
$ source oe-init-build-env
|
|
$ bitbake linux-yocto -c menuconfig
|
|
</literallayout>
|
|
Once <filename>menuconfig</filename> comes up, its standard interface allows you to
|
|
examine and configure all the kernel configuration parameters.
|
|
Once you have made your changes, simply exit the tool and save your changes to
|
|
create an updated version of the <filename>.config</filename> configuration file.
|
|
</para>
|
|
|
|
<para>
|
|
For an example that shows how to change the <filename>SMP_CONFIG</filename> parameter
|
|
using <filename>menuconfig</filename>, see the
|
|
"<link linkend='changing-the-config-smp-configuration-using-menuconfig'>Changing
|
|
the <filename>CONFIG_SMP</filename> Configuration Using <filename>menuconfig</filename></link>"
|
|
section.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='creating-config-fragments'>
|
|
<title>Creating Config Fragments</title>
|
|
|
|
<para>
|
|
Configuration fragments are simply kernel options that appear in a file.
|
|
Syntactically, the configuration statement is identical to what would appear
|
|
in the <filename>.config</filename>.
|
|
For example, issuing the following from the shell would create a config fragment
|
|
file named <filename>my_smp.cfg</filename> that enables multi-processor support
|
|
within the kernel:
|
|
<literallayout class='monospaced'>
|
|
$ echo "CONFIG_SMP=y" >> my_smp.cfg
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
Where do you put your configuration files?
|
|
You can place these configuration files in the same area pointed to by
|
|
<filename>SRC_URI</filename>.
|
|
The Yocto Project build process will pick up the configuration and add it to the
|
|
kernel's configuration.
|
|
For example, assume you add the following to your
|
|
<filename>linux-yocto_3.0.bbappend</filename> file:
|
|
<literallayout class='monospaced'>
|
|
file://my_smp.cfg
|
|
</literallayout>
|
|
You would put the config fragment file <filename>my_smp.cfg</filename> in a
|
|
sub-directory with the same root name (<filename>linux-yocto</filename>)
|
|
beneath the directory that contains your <filename>linux-yocto_3.0.bbappend</filename>
|
|
file and the build system will pick up and apply the fragment.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='fine-tuning-the-kernel-configuration-file'>
|
|
<title>Fine-tuning the Kernel Configuration File</title>
|
|
|
|
<para>
|
|
You can make sure the <filename>.config</filename> is as lean or efficient as
|
|
possible by reading the output of the kernel configuration fragment audit,
|
|
noting any issues, making changes to correct the issues, and then repeating.
|
|
</para>
|
|
|
|
<para>
|
|
As part of the Linux Yocto kernel build process, the
|
|
<filename>kernel_configcheck</filename> task runs.
|
|
This task validates the kernel configuration by checking the final
|
|
<filename>.config</filename> file against the input files.
|
|
During the check, the task produces warning messages for the following
|
|
issues:
|
|
<itemizedlist>
|
|
<listitem><para>Requested options that did not make the final
|
|
<filename>.config</filename> file.</para></listitem>
|
|
<listitem><para>Configuration items that appear twice in the same
|
|
configuration fragment.</para></listitem>
|
|
<listitem><para>Configuration items tagged as 'required' were overridden.
|
|
</para></listitem>
|
|
<listitem><para>A board overrides a non-board specific option.</para></listitem>
|
|
<listitem><para>Listed options not valid for the kernel being processed.
|
|
In other words, the option does not appear anywhere.</para></listitem>
|
|
</itemizedlist>
|
|
<note>
|
|
The <filename>kernel_configcheck</filename> task can also optionally report
|
|
if an option is overridden during processing.
|
|
</note>
|
|
</para>
|
|
|
|
<para>
|
|
For each output warning, a message points to the file
|
|
that contains a list of the options and a pointer to the config
|
|
fragment that defines them.
|
|
Collectively, the files are the key to streamlining the configuration.
|
|
</para>
|
|
|
|
<para>
|
|
To streamline the configuration, do the following:
|
|
<orderedlist>
|
|
<listitem><para>Start with a full configuration that you know
|
|
works - it builds and boots successfully.
|
|
This configuration file will be your baseline.</para></listitem>
|
|
<listitem><para>Separately run the <filename>configme</filename> and
|
|
<filename>kernel_configcheck</filename> tasks.</para></listitem>
|
|
<listitem><para>Take the resulting list of files from the
|
|
<filename>kernel_configcheck</filename> task warnings and do the following:
|
|
<itemizedlist>
|
|
<listitem><para>Drop values that are redefined in the fragment but do not
|
|
change the final <filename>.config</filename> file.</para></listitem>
|
|
<listitem><para>Analyze and potentially drop values from the
|
|
<filename>.config</filename> file that override required
|
|
configurations.</para></listitem>
|
|
<listitem><para>Analyze and potentially remove non-board specific options.
|
|
</para></listitem>
|
|
<listitem><para>Remove repeated and invalid options.</para></listitem>
|
|
</itemizedlist></para></listitem>
|
|
<listitem><para>After you have worked through the output of the kernel configuration
|
|
audit, you can re-run the <filename>configme</filename>
|
|
and <filename>kernel_configcheck</filename> tasks to see the results of your
|
|
changes.
|
|
If you have more issues, you can deal with them as described in the
|
|
previous step.</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
|
|
<para>
|
|
Iteratively working through steps two through four eventually yields
|
|
a minimal, streamlined configuration file.
|
|
Once you have the best <filename>.config</filename>, you can build the Linux
|
|
Yocto kernel.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="usingpoky-changes-updatingimages">
|
|
<title>Updating Existing Images</title>
|
|
|
|
<para>
|
|
Often, rather than re-flashing a new image, you might wish to install updated
|
|
packages into an existing running system.
|
|
You can do this by first sharing the <filename>tmp/deploy/ipk/</filename> directory
|
|
through a web server and then by changing <filename>/etc/opkg/base-feeds.conf</filename>
|
|
to point at the shared server.
|
|
Following is an example:
|
|
<literallayout class='monospaced'>
|
|
$ src/gz all http://www.mysite.com/somedir/deploy/ipk/all
|
|
$ src/gz armv7a http://www.mysite.com/somedir/deploy/ipk/armv7a
|
|
$ src/gz beagleboard http://www.mysite.com/somedir/deploy/ipk/beagleboard
|
|
</literallayout>
|
|
</para>
|
|
</section>
|
|
|
|
<section id="usingpoky-changes-prbump">
|
|
<title>Incrementing a Package Revision Number</title>
|
|
|
|
<para>
|
|
If a committed change results in changing the package output,
|
|
then the value of the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PR'>PR</ulink></filename>
|
|
variable needs to be increased
|
|
(or "bumped") as part of that commit.
|
|
This means that for new recipes you must be sure to add the <filename>PR</filename>
|
|
variable and set its initial value equal to "r0".
|
|
Failing to define <filename>PR</filename> makes it easy to miss when you bump a package.
|
|
Note that you can only use integer values following the "r" in the
|
|
<filename>PR</filename> variable.
|
|
</para>
|
|
|
|
<para>
|
|
If you are sharing a common <filename>.inc</filename> file with multiple recipes,
|
|
you can also use the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-INC_PR'>INC_PR</ulink></filename>
|
|
variable to ensure that
|
|
the recipes sharing the <filename>.inc</filename> file are rebuilt when the
|
|
<filename>.inc</filename> file itself is changed.
|
|
The <filename>.inc</filename> file must set <filename>INC_PR</filename>
|
|
(initially to "r0"), and all recipes referring to it should set <filename>PR</filename>
|
|
to "$(INC_PR).0" initially, incrementing the last number when the recipe is changed.
|
|
If the <filename>.inc</filename> file is changed then its
|
|
<filename>INC_PR</filename> should be incremented.
|
|
</para>
|
|
|
|
<para>
|
|
When upgrading the version of a package, assuming the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PV'>PV</ulink></filename>
|
|
changes, the <filename>PR</filename> variable should be reset to "r0"
|
|
(or "$(INC_PR).0" if you are using <filename>INC_PR</filename>).
|
|
</para>
|
|
|
|
<para>
|
|
Usually, version increases occur only to packages.
|
|
However, if for some reason <filename>PV</filename> changes but does not
|
|
increase, you can increase the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PE'>PE</ulink></filename>
|
|
variable (Package Epoch).
|
|
The <filename>PE</filename> variable defaults to "0".
|
|
</para>
|
|
|
|
<para>
|
|
Version numbering strives to follow the
|
|
<ulink url='http://www.debian.org/doc/debian-policy/ch-controlfields.html'>
|
|
Debian Version Field Policy Guidelines</ulink>.
|
|
These guidelines define how versions are compared and what "increasing" a version means.
|
|
</para>
|
|
|
|
<para>
|
|
There are two reasons for following the previously mentioned guidelines.
|
|
First, to ensure that when a developer updates and rebuilds, they get all the changes to
|
|
the repository and do not have to remember to rebuild any sections.
|
|
Second, to ensure that target users are able to upgrade their
|
|
devices using package manager commands such as <filename>opkg upgrade</filename>
|
|
(or similar commands for dpkg/apt or rpm-based systems).
|
|
</para>
|
|
|
|
<para>
|
|
The goal is to ensure the Yocto Project has packages that can be upgraded in all cases.
|
|
</para>
|
|
</section>
|
|
|
|
<section id="usingpoky-configuring-DISTRO_PN_ALIAS">
|
|
<title>Handling a Package Name Alias</title>
|
|
<para>
|
|
Sometimes a package name you are using might exist under an alias or as a similarly named
|
|
package in a different distribution.
|
|
The Yocto Project implements a <filename>distro_check</filename>
|
|
task that automatically connects to major distributions
|
|
and checks for these situations.
|
|
If the package exists under a different name in a different distribution, you get a
|
|
<filename>distro_check</filename> mismatch.
|
|
You can resolve this problem by defining a per-distro recipe name alias using the
|
|
<filename><ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_PN_ALIAS'>DISTRO_PN_ALIAS</ulink></filename>
|
|
variable.
|
|
</para>
|
|
|
|
<para>
|
|
Following is an example that shows how you specify the <filename>DISTRO_PN_ALIAS</filename>
|
|
variable:
|
|
<literallayout class='monospaced'>
|
|
DISTRO_PN_ALIAS_pn-PACKAGENAME = "distro1=package_name_alias1 \
|
|
distro2=package_name_alias2 \
|
|
distro3=package_name_alias3 \
|
|
..."
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
If you have more than one distribution alias, separate them with a space.
|
|
Note that the Yocto Project currently automatically checks the
|
|
Fedora, OpenSuSE, Debian, Ubuntu,
|
|
and Mandriva distributions for source package recipes without having to specify them
|
|
using the <filename>DISTRO_PN_ALIAS</filename> variable.
|
|
For example, the following command generates a report that lists the Linux distributions
|
|
that include the sources for each of the Yocto Project recipes.
|
|
<literallayout class='monospaced'>
|
|
$ bitbake world -f -c distro_check
|
|
</literallayout>
|
|
The results are stored in the <filename>build/tmp/log/distro_check-${DATETIME}.results</filename>
|
|
file found in the Yocto Project files area.
|
|
</para>
|
|
</section>
|
|
|
|
<section id="building-software-from-an-external-source">
|
|
<title>Building Software from an External Source</title>
|
|
|
|
<para>
|
|
By default, the Yocto Project build system does its work from within the
|
|
<link linkend='yocto-project-build-directory'>Yocto Project Build Directory</link>.
|
|
The build process involves fetching the source files, unpacking them, and then patching them
|
|
if necessary before the build takes place.
|
|
</para>
|
|
|
|
<para>
|
|
Situations exist where you might want to build software from source files that are external to
|
|
and thus outside of the <link linkend='yocto-project-files'>Yocto Project Files</link>.
|
|
For example, suppose you have a project that includes a new BSP with a heavily customized
|
|
kernel, a very minimal image, and some new user-space recipes.
|
|
And, you want to minimize the exposure to the Yocto Project build system to the
|
|
development team so that they can focus on their project and maintain everyone's workflow
|
|
as much as possible.
|
|
In this case, you want a kernel source directory on the development machine where the
|
|
development occurs.
|
|
You want the recipe's
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
|
|
variable to point to the external directory and use it as is, not copy it.
|
|
</para>
|
|
|
|
<para>
|
|
To build from software that comes from an external source, all you need to do is
|
|
change your recipe so that it inherits the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-externalsrc'><filename>externalsrc.bbclass</filename></ulink>
|
|
class and then sets the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>
|
|
variable to point to your external source code.
|
|
Here are the statements to put in your recipe:
|
|
<literallayout class='monospaced'>
|
|
inherit externalsrc
|
|
S = "/some/path/to/your/package/source"
|
|
</literallayout>
|
|
</para>
|
|
|
|
<para>
|
|
It is important to know that the <filename>externalsrc.bbclass</filename> assumes that the
|
|
source directory <filename>S</filename> and the build directory
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-B'><filename>B</filename></ulink>
|
|
are different even though by default these directories are the same.
|
|
This assumption is important because it supports building different variants of the recipe
|
|
by using the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-BBCLASSEXTEND'><filename>BBCLASSEXTEND</filename></ulink>
|
|
variable.
|
|
You could allow the build directory to be the same as the source directory but you would
|
|
not be able to build more than one variant of the recipe.
|
|
Consequently, if you are building multiple variants of the recipe, you need to establish a
|
|
build directory that is different than the source directory.
|
|
</para>
|
|
</section>
|
|
</chapter>
|
|
|
|
<!--
|
|
vim: expandtab tw=80 ts=4
|
|
-->
|