From: Tom Zanussi <tom.zanu...@intel.com>
This patch contains a set of changes to The Yocto Project Development
Manual's 'Appendix A. BSP Development Example' to reflect input from
several users and to add some changes for problems and opportunities
for enhancement that I noted when doing my own testing.
Signed-off-by: Tom Zanussi <tom.zanu...@intel.com>
---
.../dev-manual/dev-manual-bsp-appendix.xml | 188 ++++++++++++++++----
1 files changed, 154 insertions(+), 34 deletions(-)
diff --git a/documentation/dev-manual/dev-manual-bsp-appendix.xml
b/documentation/dev-manual/dev-manual-bsp-appendix.xml
index 485064d..00f5edf 100644
--- a/documentation/dev-manual/dev-manual-bsp-appendix.xml
+++ b/documentation/dev-manual/dev-manual-bsp-appendix.xml
@@ -11,7 +11,8 @@
<itemizedlist>
<listitem><para>No previous preparation or use of the Yocto
Project.</para></listitem>
<listitem><para>Use of the Crown Bay Board Support Package (BSP) as a
base BSP from
- which to work from.</para></listitem>
+ which to work from (we'll be starting with the Crown Bay BSP but
will be building
+ a new 'atom-pc' BSP using the Crown Bay as as starting
point).</para></listitem>
<listitem><para>Shell commands assume
<filename>bash</filename></para></listitem>
<listitem><para>Example was developed on an Intel-based Core i7
platform running
Ubuntu 10.04 LTS released in April of 2010.</para></listitem>
@@ -29,6 +30,24 @@
"<link linkend='local-yp-release'>Yocto Project Release</link>"
for information on how to get these files.
</para>
+ <para>
+ For example, one way to get the Yocto Project files using git is to
clone the poky repo:
+ <literallayout class='monospaced'>
+ $ git clone git://git.yoctoproject.org/poky
+ $ cd poky
+ </literallayout>
+ </para>
+ <para>
+ Alternatively, you can start with the downloaded poky edison tarball:
+ <literallayout class='monospaced'>
+ $ tar xfj poky-edison-6.0.tar.bz2
+ $ cd poky
+ </literallayout>
+ Note that if you're using the tarball method, you can ignore all the
steps below that
+ ask you to carry out git operations - you already have the results of
those operations
+ in the form of the edison release tarballs, and there's nothing left
to do other than
+ extract those tarballs into the proper locations.
+ </para>
<para>
Once you have the local <filename>poky</filename> Git repository set
up,
@@ -44,7 +63,6 @@
These commands create a local branch named <filename>edison</filename>
that tracks the remote branch of the same name.
<literallayout class='monospaced'>
- $ cd poky
$ git checkout -b edison origin/edison
Switched to a new branch 'edison'
</literallayout>
@@ -58,7 +76,10 @@
For this example, the base BSP is the <trademark
class='registered'>Intel</trademark>
<trademark class='trade'>Atom</trademark> Processor E660 with Intel
Platform
Controller Hub EG20T Development Kit, which is otherwise referred to
as "Crown Bay."
- The BSP layer is <filename>meta-crownbay</filename>.
+ The BSP layer is <filename>meta-crownbay</filename>. The Base BSP is
simply the BSP
+ we'll be using as a starting point, so don't worry if you don't
actually have Crown Bay
+ hardware - using the steps below, we'll be transforming it into a BSP
that should be
+ able to boot on generic atom-pc (netbook) hardware.
</para>
<para>
@@ -73,27 +94,48 @@
<para>
You need to have the base BSP layer on your development system.
Similar to the local Yocto Project files, you can get the BSP
- layer one of two ways:
+ layer in one of two ways:
download the BSP tarball and extract it, or set up a local Git
repository that
has the Yocto Project BSP layers.
You should use the same method that you used to get the local Yocto
Project files earlier.
See "<link linkend='getting-setup'>Getting Setup</link>" for
information on how to get
the BSP files.
</para>
-
<para>
- This example assumes the local <filename>meta-intel</filename> Git
repository is
- inside the local <filename>poky</filename> Git repository.
- The <filename>meta-intel</filename> Git repository contains all the
metadata
- that supports BSP creation.
+ This example assumes the BSP layer will be located within a directory
named
+ <filename>meta-intel</filename> contained within the
<filename>poky</filename>
+ parent directory. The steps below will automatically create the
+ <filename>meta-intel</filename> directory and the contained
meta-crownbay
+ starting point in both the git and the tarball cases.
</para>
-
<para>
+ If you're using the git method, you could do the following to create
+ the starting layout (you should make sure you've already cd'ed into
+ the poky directory in the steps above):
+ <literallayout class='monospaced'>
+ $ git clone git://git.yoctoproject.org/meta-intel.git
+ $ cd meta-intel
+ </literallayout>
+ </para>
+ <para>
+ Alternatively, you can start with the downloaded meta-intel edison
tarball
+ (again, you should make sure you've already cd'ed into the poky
directory
+ in the steps above):
+ <literallayout class='monospaced'>
+ $ tar xfj crownbay-noemgd-edison-6.0.0.tar.bz2
+ $ cd meta-intel
+ </literallayout>
+ </para>
+
+ <para>
+ The <filename>meta-intel</filename> directory contains all the
metadata
+ that supports BSP creation. If you're using the git method, the
following
+ step will make switch to the edison metadata; if you're using the
tarball
+ method, you already have the correct metadata and can skip to the next
step.
Because <filename>meta-intel</filename> is its own Git repository, you
will want
to be sure you are in the appropriate branch for your work.
For this example we are going to use the <filename>edison</filename>
branch.
<literallayout class='monospaced'>
- $ cd meta-intel
$ git checkout -b edison origin/edison
Switched to a new branch 'edison'
</literallayout>
@@ -112,15 +154,12 @@
<para>
For this example, the new layer will be named
<filename>meta-mymachine</filename>.
- The name must follow the BSP layer naming convention, which is
+ The name should follow the BSP layer naming convention, which is
<filename>meta-<name></filename>.
- The following example assumes your working directory is
<filename>meta-intel</filename>
+ The following assumes your working directory is
<filename>meta-intel</filename>
inside the local Yocto Project files.
- If you downloaded and expanded a Crown Bay tarball then you simply
copy the resulting
- <filename>meta-crownbay</filename> directory structure to a location
of your choice.
- Good practice for a Git repository, however, is to just copy the new
layer alongside
- the existing
- BSP layers in the <filename>meta-intel</filename> Git repository:
+ To start your new layer, just copy the new layer alongside the existing
+ BSP layers in the <filename>meta-intel</filename> directory:
<literallayout class='monospaced'>
$ cp -a meta-crownbay/ meta-mymachine
</literallayout>
@@ -162,9 +201,13 @@
</para>
<para>
- The next step makes changes to <filename>mymachine.conf</filename>
itself.
- The only changes needed for this example are changes to the
comment lines.
- Here we simply substitute the Crown Bay name with an appropriate
name.
+ The next step is to make changes to the
<filename>mymachine.conf</filename> itself.
+ The only changes we want to make for this example are to the
comment lines. Changing
+ comments of course is never strictly necessary, but it's alway
good form to make
+ them reflect reality as far as possible.
+
+ Here simply substitute the Crown Bay name with an appropriate name
for the BSP (mymachine
+ in this case) and change the description to something that
describes your hardware.
</para>
<para>
@@ -176,7 +219,8 @@
</para>
<para>
- The next configuration file in the new BSP layer we need to edit
is <filename>layer.conf</filename>.
+ The next configuration file in the new BSP layer we need to edit is
+ <filename>meta-mymachine/conf/layer.conf</filename>.
This file identifies build information needed for the new layer.
You can see the
"<ulink
url='http://www.yoctoproject.org/docs/1.1/bsp-guide/bsp-guide.html#bsp-filelayout-layer'>Layer
Configuration File</ulink>" section in
@@ -232,7 +276,7 @@
the remaining one that doesn't support EMGD.
These commands take care of the
<filename>recipes-bsp</filename> recipes:
<literallayout class='monospaced'>
- $ rm -rf meta-mymachine/recipes-graphics/xorg-xserver/*emgd*
+ $ rm -rf meta-mymachine/recipes-bsp/formfactor/formfactor/crownbay
$ mv meta-mymachine/recipes-bsp/formfactor/formfactor/crownbay-noemgd/ \
meta-mymachine/recipes-bsp/formfactor/formfactor/mymachine
</literallayout>
@@ -248,7 +292,6 @@
be sure to rename remaining directories appropriately.
The following commands clean up the
<filename>recipes-graphics</filename> directory:
<literallayout class='monospaced'>
- $ rm -rf meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-emgd*
$ rm -rf
meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/crownbay
$ mv
meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/crownbay-noemgd
\
meta-mymachine/recipes-graphics/xorg-xserver/xserver-xf86-config/mymachine
@@ -304,6 +347,9 @@
The <filename>SRCREV_machine</filename> and
<filename>SRCREV_meta</filename>
statements point to the exact commits used by the Yocto
Project development team
in their source repositories that identify the right kernel
for our hardware.
+ The SRCREV values are simply git commit ids that identify
which commit on each
+ of the kernel branches (machine and meta) will be checked out
and used to build
+ the kernel.
</para>
<para>
@@ -323,12 +369,12 @@
SRCREV_machine_pn-linux-yocto_crownbay ?= \
"2247da9131ea7e46ed4766a69bb1353dba22f873"
SRCREV_meta_pn-linux-yocto_crownbay ?= \
- "67a46a608f47c19f16995be7de7b272025864b1b"
+ "d05450e4aef02c1b7137398ab3a9f8f96da74f52"
SRCREV_machine_pn-linux-yocto_crownbay-noemgd ?= \
"2247da9131ea7e46ed4766a69bb1353dba22f873"
SRCREV_meta_pn-linux-yocto_crownbay-noemgd ?= \
- "67a46a608f47c19f16995be7de7b272025864b1b"
+ "d05450e4aef02c1b7137398ab3a9f8f96da74f52"
</literallayout>
</para>
@@ -350,17 +396,33 @@
and insert the commit identifiers to identify the kernel in
which we
are interested, which will be based on the
<filename>atom-pc-standard</filename>
kernel.
+ In this case, because we're working with the edison branch of
everything, we
+ need to use the SRCREVs for the atom-pc branch which are
associated with the
+ edison release. To find those, we need to find the SRCREVs
that edison uses
+ for the atom-pc branch, which we find in the
+
<filename>poky/meta-yocto/recipes-kernel/linux/linux-yocto_3.0.bbappend</filename>
+ file. The machine SRCREV we want is in the
SRCREV_machine_atom-pc variable. The
+ meta SRCREV isn't specified in this file, so it must be
specified in the base
+ kernel recipe in the
+
<filename>poky/meta/recipes-kernel/linux/linux-yocto_3.0.bb</filename>
+ file, in the SRCREV_meta variable found there. It happens to
be the same
+ as the value we already inherited from the meta-crownbay BSP.
Here are the final <filename>SRCREV</filename> statements:
<literallayout class='monospaced'>
SRCREV_machine_pn-linux-yocto_mymachine ?= \
- "06c798f25a19281d7fa944b14366dd75820ba009"
+ "1e18e44adbe79b846e382370eb29bc4b8cd5a1a0"
SRCREV_meta_pn-linux-yocto_mymachine ?= \
- "67a46a608f47c19f16995be7de7b272025864b1b"
+ "d05450e4aef02c1b7137398ab3a9f8f96da74f52"
</literallayout>
</para>
<para>
- If you are familiar with Git repositories you probably wonât
have trouble locating the
+ Note that in this example, we're using the SRCREVs 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'd want to use
the most recent
+ SRCREVs taken directly from the kernel repo. We won't be
doing that for this
+ example, but if you do base a future BSP on master and
+ if you are familiar with Git repositories you probably wonât
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>
@@ -394,19 +456,25 @@
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>.
+ Note that since we're 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/mymachine"
+ KMACHINE_mymachine = "yocto/standard/common-pc/atom-pc"
KERNEL_FEATURES_append_mymachine += " cfg/smp.scc"
SRCREV_machine_pn-linux-yocto_mymachine ?= \
- "06c798f25a19281d7fa944b14366dd75820ba009"
+ "1e18e44adbe79b846e382370eb29bc4b8cd5a1a0"
SRCREV_meta_pn-linux-yocto_mymachine ?= \
- "67a46a608f47c19f16995be7de7b272025864b1b"
+ "d05450e4aef02c1b7137398ab3a9f8f96da74f52"
</literallayout>
</para>
</section>
@@ -455,7 +523,7 @@
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
+ The <filename>yocto-build</filename> directory contains a
<filename>conf</filename> directory that has
two configuration files you will need to check:
<filename>bblayers.conf</filename>
and <filename>local.conf</filename>.</para></listitem>
@@ -492,7 +560,7 @@
</section>
<section id='building-the-image-app'>
- <title>Building the Image</title>
+ <title>Building and Booting the Image</title>
<para>
To build the image for our <filename>meta-mymachine</filename> BSP
enter the following command
@@ -513,6 +581,58 @@
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 e.g a USB
device.
+ To prepare a bootable USB device, insert a USB flash drive into your
build system and
+ copy the .hddimage, located in the
<filename>poky/build/tmp/deploy/images</filename>
+ directory after a successful to the flash drive. Assuming the USB
flash drive
+ takes device /dev/sdf, use dd to copy the live image to it. For
+ example:
+ </para>
+
+ <literallayout class='monospaced'>
+ # dd if=core-image-sato-mymachine-20111101223904.hddimg of=/dev/sdf
+ # sync
+ # eject /dev/sdf
+ </literallayout>
+
+ <para>
+ This should give you a bootable USB flash device. Insert the device
+ into a bootable USB socket on the target, and power on. This should
+ result in a system booted to the Sato graphical desktop.
+ </para>
+
+ <para>
+ For reference, the sato image produced by the above steps for edison
looked
+ like this in terms of size. If your sato image is much different from
this,
+ you probably made a mistake in one of the above steps:
+ </para>
+
+ <literallayout class='monospaced'>
+ 358715392 2011-11-01 19:11
core-image-sato-mymachine-20111101223904.hddimg
+ </literallayout>
+
+ <para>
+ Note that the above 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 README.hardware file in the top-level poky
directory
+ also provides some suggestions for things to try if booting fails with
strange
+ error messages.
+ </para>
+
+ <para>
+ Note also that 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 may not be completely functional though it should at least
boot to a text
+ prompt. Specifically, it may fail to boot into graphics without some
tweaking. One
+ possible next step if that ends up being the case would be to replace
the mymachine.conf
+ contents with the contents of atom-pc.conf and replace xorg.conf with
the atom-pc xorg.conf
+ in meta-yocto see if it fares any better. In any case, following the
above steps should
+ give you a buildable and probably 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>
--
1.7.0.4
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