path: root/distribution/yocto-advanced/pres_yocto-advanced.tex

\input{configpres}

\title{YOCTO - Advanced}
\maketitle

\begin{frame}
\frametitle{Agenda}
\begin{itemize}
\item Using BSP layers (beaglebone)
\item Build a predefined image (beaglebone)
\item Creating a layer
\item Define a distribution
\item Create an image
\item Writing recipes
\item Yocto \& ELBE combined?
\end{itemize}
\end{frame}

\subsection{Using BSP layers}

\begin{frame}[fragile]
\frametitle{folder layout}
\begin{verbatim}
meta-mylayer
+ conf
|  + layer.conf
+ classes
|  + class1.bbclass
|  + class2.bbclass
+ recipes-category1
|  + package-1
|      + package-1.bb
|  + package-2
|      + package-2.bb
+ recipes-category2
| ..
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
	\frametitle{meta-*/conf/layer.conf}
	each layer needs a configuration file
	\begin{itemize}
		\item add conf and class directories to BBPATH
			\begin{verbatim}BBPATH =. "${LAYERDIR}"\end{verbatim}
		\pause
		\item add recipe directories to BBFILES
			\begin{verbatim}BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
			${LAYERDIR}/recipes-*/*/*.bbappend"\end{verbatim}
		\pause
		\item add layer name to BBFILE\_COLLECTIONS
			\begin{verbatim}BBFILE_COLLECTIONS += "mylayer"\end{verbatim}
		\pause
		\item set root of the layer
			\begin{verbatim}BBFILE_PATTERN_mylayer = "^${LAYERDIR}/"\end{verbatim}
		\pause
		\item set default priority of the layer
			\begin{verbatim}BBFILE_PRIORITY_mylayer = "5"\end{verbatim}
		\pause
		\item set version of layer (only increment if dependencies with other
			layers are affected)
			\begin{verbatim}LAYERVERSION_mylayer = "2"\end{verbatim}
		\pause
		\item set dependencies to other layers
			\begin{verbatim}LAYERDEPENDS_mylayer = "meta-yocto"\end{verbatim}
	\end{itemize}
\end{frame}

\begin{frame}
\frametitle{bitbake-layers}
is useful to debug relations between different layers, options are:
\begin{description}
\item [show-layers] shows the current configured layers
		\pause
\item [show-recipes] lists available recipes and the layers that provide them.
		\pause
\item [show-overlayed] lists overlayed recipes
		\pause
\item [show-appends] lists .bbappend files
	and the recipe files to which they apply
		\pause
\item [show-cross-depends] lists dependency relationships
	between recipes that cross layer boundaries
		\pause
\item [flatten] flattens the layer configuration
	into a separate output directory.
\end{description}
\end{frame}

\begin{frame}
\frametitle{definitions}
\begin{itemize}
	\item It is possible for a recipe with a lower version number PV in a layer
that has a higher priority to take precedence.
		\pause
	\item Also, the layer priority does not currently affect the precedence
order of .conf or .bbclass files. Future versions of BitBake might address this.
\end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{get an existing layer}
retrive the layer from your BSP/SoC vendor
\begin{verbatim}
poky % git clone git://git.yoctoproject.org/meta-ti
poky % git branch -r
poky % git checkout <RELEASE>
\end{verbatim}
		\pause
have a look at it's dependencies
\begin{verbatim}
poky % cat meta-ti/conf/layer.conf | grep LAYERDEPENDS
LAYERDEPENDS_ti = "core"
\end{verbatim}
		\pause
and retrieve them also
\begin{verbatim}
poky % git clone -b daisy git://git.yoctoproject.org/meta-fsl-arm
\end{verbatim}
		\pause
check dependencies again
\begin{verbatim}
poky % git clone /home/devel/yocto/meta-mini
\end{verbatim}
		\pause
\dots no more dependencies?! \dots OK - finished.
\end{frame}

\begin{frame}[fragile]
\frametitle{generate a new build environment}
\begin{verbatim}
poky % . oe-init-build-env build-ti
poky/build-ti %
\end{verbatim}
\end{frame}

\subsection{Build a predefined image}
\begin{frame}
\frametitle{overview}
builds are configured using two configuration files
\begin{itemize}
	\item build-ti/conf/bblayers.conf
	\item build-ti/conf/local.conf
\end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{bblayers.conf}
additional layers are added with absolute! path to the BBLAYERS variable
\begin{verbatim}
BBLAYERS ?= " \
  /home/devel/poky/meta \
  /home/devel/poky/meta-yocto \
  /home/devel/poky/meta-yocto-bsp \
  "
\end{verbatim}
\pause
\begin{verbatim}
% bitbake-layers show-layers
layer                 path                                  priority
=====================================================================
meta                  /home/devel/poky/meta                 5
meta-yocto            /home/devel/poky/meta-yocto           5
meta-yocto-bsp        /home/devel/poky/meta-yocto-bsp       5
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{add ti layers}
modify the BBLAYERS variable in bblayers.conf
\begin{verbatim}
BBLAYERS ?= " \
  /home/devel/poky/meta \
  /home/devel/poky/meta-yocto \
  /home/devel/poky/meta-yocto-bsp \
  /home/devel/poky/meta-ti \
  "
\end{verbatim}
\pause
\begin{verbatim}
% bitbake-layers show-layers
layer                 path                                  priority
=====================================================================
meta                  /home/devel/poky/meta                 5
meta-yocto            /home/devel/poky/meta-yocto           5
meta-yocto-bsp        /home/devel/poky/meta-yocto-bsp       5
meta-ti               /home/devel/poky/meta-ti              5
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{overlayed recipes}
to see which recipes replace official ones:
\begin{verbatim}
poky/build-ti % bitbake-layers show-overlayed
Parsing recipes..done.
=== Overlayed recipes ===
directfb:
  meta                 1.7.1
  meta-ti              1.6.3
directfb-examples:
  meta                 1.7.0
  meta-ti              1.6.0
xserver-xorg:
  meta                 2:1.15.0
  meta-ti              2:1.14.4
\end{verbatim}
\end{frame}

\begin{frame}
\frametitle{local.conf}
is used to configure
\begin{itemize}
	\item the target machine
		\pause
	\item paths
		\pause
	\item the used distribution
		\pause
	\item package formats
		\pause
	\item arch of developer machine
		\pause
	\item additional image features
		\pause
	\item use additional classes
		\pause
	\item enable testing
		\pause
	\item devshell terminal
		\pause
	\item patch resolver
		\pause
	\item disk monitoring
		\pause
	\item sstate mirrors
		\pause
	\item qemu configuration
		\pause
	\item incompatible licenses, e.g. INCOMPATIBLE\_LICENSE = “GPLv3”
\end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{configure the machine}
to get a list of currently available machines configs:
\begin{verbatim}
poky/build-ti % grep -r '@NAME' ../meta*/conf/machine
\end{verbatim}
beaglebone.conf - seems to be the one for our bord, so set
imx6qsabrelite.conf - seems to be the one for our bord, so set
\begin{verbatim}
MACHINE ??= "beaglebone"
\end{verbatim}
in conf/local.conf
\end{frame}

\begin{frame}[fragile]
\frametitle{package format}
as we realized with toaster, rpm packaging consumes a lot of CPU time, so lets
try ipk, by setting
\begin{verbatim}
PACKAGE_CLASSES ?= "package_ipk"
\end{verbatim}
in conf/local.conf
\end{frame}

\begin{frame}[fragile]
\frametitle{set extra image features}
we want an image suitable for development, so set
\begin{verbatim}
EXTRA_IMAGE_FEATURES = "debug-tweaks tools-debug \
  eclipse-debug tools-profile"
\end{verbatim}
in conf/local.conf
\end{frame}

\begin{frame}[fragile]
\frametitle{build an predefined image}
use
\begin{verbatim}
ls ../*/*/images/
\end{verbatim}
to get a list of predefined images; however none of them fits my needs\dots
		\pause
\begin{verbatim}
poky/build-fsl % cd ..
poky % git clone -b daisy https://github.com/Freescale/meta-fsl-demos.git
poky % git clone -b daisy git://git.openembedded.org/meta-openembedded
poky % cd -
\end{verbatim}
		\pause
and edit conf/bblayers.conf, to match
\begin{verbatim}
BBLAYERS ?= " \
  /home/devel/poky/meta \
  /home/devel/poky/meta-yocto \
  /home/devel/poky/meta-yocto-bsp \
  /home/devel/poky/meta-fsl-arm \
  /home/devel/poky/meta-fsl-arm-extra \
  /home/devel/poky/meta-openembedded/meta-oe \
  /home/devel/poky/meta-fsl-demos \
  "
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{build a qt demo image}
\begin{verbatim}
poky/build-ti % source toaster start
poky/build-ti % bitbake qt4e-demo-image
Currently 4 running tasks (26 of 4459):
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{build a ti demo image}
\dots back from coffee break
\begin{verbatim}
ERROR: No new tasks can be executed since
       the disk space monitor action is "STOPTASKS"!
\end{verbatim}
what happened??
		\pause
\begin{verbatim}
poky/build-ti % df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda4       367G  348G  850M 100% /
poky/build-ti % du -sm .
31026   .
poky/build-ti % du -sm ../build
29172   ../build/
\end{verbatim}
		\pause
\dots so the solution is to cleanup the disk and run
\begin{verbatim}
poky/build-ti % bitbake qt4e-demo-image
\end{verbatim}
again.

A different behaviour can be configured in 'conf/local.conf'.
\end{frame}

\begin{frame}[fragile]
\frametitle{example of an issue with a sabrelite board}
\begin{verbatim}
ERROR: To use 'gpu-viv-bin-mx6q'
  you need to accept the Freescale EULA
  at '/home/local/src/poky/meta-ti-arm/EULA'.
  Please read it and in case you accept it, write:
  ACCEPT_FSL_EULA = "1" in your local.conf.
ERROR: Function failed: do_unpack
ERROR: Logfile of failure stored in:
  /home/local/src/poky/build-ti/tmp/work/
   cortexa9hf-vfp-neon-mx6-poky-linux-gnueabi/
   gpu-viv-bin-mx6q/1_3.10.17-1.0.0-hfp-r0/temp/
   log.do_unpack.6795
ERROR: Task 1105 (/home/local/src/poky/meta-ti-arm/
  recipes-graphics/gpu-viv-bin-mx6q/
  gpu-viv-bin-mx6q_3.10.17-1.0.0-hfp.bb, do_unpack) failed
  with exit code '1'
\end{verbatim}
		\pause
to solve this issue:
\begin{verbatim}
poky/build-ti % echo 'ACCEPT_FSL_EULA = "1"' >> conf/local.conf
\end{verbatim}
		\pause
\dots and run
\begin{verbatim}
poky/build-ti % bitbake qt4e-demo-image
\end{verbatim}
again.
\end{frame}

\begin{frame}[fragile]
\frametitle{flashing the image}
if the build is completed the image can be transfered to a sdcard:
\begin{verbatim}
poky/build-ti % sudo fdisk /dev/mmcblk0
# create a
# * bootable
# * primary partition with
# * about 100 MB and
# * Windows vFat format
# and another primary partition with Linux Ext format
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{flashing the image \#2}
\begin{verbatim}
poky/build-ti % sudo mkfs.vfat -F 16 -n boot /dev/mmcblk0p1
poky/build-ti % sudo mke2fs -j -L "root" /dev/mmcblk0p2
poky/build-ti % sudo mount /dev/mmcblk0p1 /mnt
poky/build-ti % sudo cp -a tmp/deploy/images/beaglebone/MLO-beaglebone \
  /mnt/MLO
poky/build-ti % sudo cp -a \
  tmp/deploy/images/beaglebone/u-boot-beaglebone.img \
  /mnt/u-boot.img
poky/build-ti % sudo umount /mnt
poky/build-ti % sudo mount /dev/mmcblk0p2 /mnt
poky/build-ti % sudo tar xjf \
  tmp/deploy/images/qt4e-demo-image-beaglebone.tar.bz2 -C /mnt
poky/build-ti % sudo umount /mnt
\end{verbatim}
\end{frame}

\subsection{Creating a layer}
\begin{frame}[fragile]
\frametitle{with yocto helper script}
\begin{verbatim}
poky/build-ti % cd ..
poky % yocto-layer create mini
Please enter the layer priority you'd like to use for the layer:
[default: 6] <return>
Would you like to have an example recipe created? (y/n)
[default: n] <return>
Would you like to have an example bbappend file created? (y/n)
[default: n] <return>
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{manage the layer with git}
\begin{verbatim}
poky % cd meta-mini
poky/meta-mini % git init .
poky/meta-mini % git add *
poky/meta-mini % git commit -sam 'inital version'
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\begin{verbatim}
poky/meta-mini % cd ../build-ti
\end{verbatim}
edit 'conf/bblayers.conf':
\begin{verbatim}
BBLAYERS ?= " \
  /home/devel/poky/meta \
  /home/devel/poky/meta-yocto \
  /home/devel/poky/meta-yocto-bsp \
  /home/devel/poky/meta-ti \
  /home/devel/poky/meta-mini \
  "
\end{verbatim}
\end{frame}

\subsection{Define a distribution}
\begin{frame}
\frametitle{why define a distribution?}
\begin{itemize}
\item naming of the toolchain (codenames, vendor)
		\pause
\item version numbers
		\pause
\item enable default features
\end{itemize}
\end{frame}

\begin{frame}
\frametitle{distro features: file-systems}
\begin{description}
\item[cramfs] CramFS support
		\pause
\item[ext2] tools for supporting for devices with internal HDD/Microdrive
	for storing files (instead of Flash only devices)
		\pause
\item[nfs] NFS client support (for mounting NFS exports on device)
		\pause
\item[smbfs] SMB networks client support
	(for mounting Samba/Microsoft Windows shares on device)
\end{description}
\end{frame}

\begin{frame}
\frametitle{distro features: hardware support}
\begin{description}
\item[alsa] ALSA/sound support
	(OSS compatibility kernel modules installed if available)
		\pause
\item[bluetooth] bluetooth support (integrated BT only)
		\pause
\item[irda] IrDA support
		\pause
\item[wifi] WiFi support (integrated only).
		\pause
\item[keyboard] keyboard support (e.g. keymaps will be loaded during boot)
\end{description}
\end{frame}

\begin{frame}
\frametitle{distro features: grahpics}
\begin{description}
\item[opengl] the Open Graphics Library, which is a cross-language,
	multi-platform application programming interface used for rendering two
	and three-dimensional graphics
		\pause
\item[directfb] DirectFB support
\end{description}
\end{frame}

\begin{frame}
\frametitle{distro features: networking}
\begin{description}
\item[ipsec] IPSec support
		\pause
\item[ipv6] IPv6 support
		\pause
\item[ppp] PPP dialup support
\end{description}
\end{frame}

\begin{frame}
\frametitle{distro features: bus support}
\begin{description}
\item[pci] PCI bus support
		\pause
\item[pcmcia] PCMCIA/CompactFlash support
		\pause
\item[usbgadget] USB Gadget Device support (for USB networking/serial/storage)
		\pause
\item[usbhost] USB Host support
	(allows to connect external keyboard, mouse, storage, network etc)
\end{description}
\end{frame}

\begin{frame}
\frametitle{distro features: software}
\begin{description}
\item[systemd] support for this init manager, which is a full replacement of
	for init with parallel starting of services, reduced shell overhead,
	and other features. This init manager is used by many distributions
		\pause
\item[wayland] the Wayland display server protocol
	and the library that supports it
		\pause
\item[x11] X server and libraries
\end{description}
\end{frame}

\begin{frame}[fragile]
\frametitle{use a DISTRO\_FEATURE}
Normally the distro features are used in package groups in a core layer.
e.g. 'meta/recipes-core/packagegroups/packagegroup-base.bb':
\begin{verbatim}
PACKAGES = ' \
	..
	${@base_contains("DISTRO_FEATURES", \
	                 "opengl", "packagegroup-opengl", "", d)} \
	..
	'
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{exkurs: package groups}
are recipes that are used to group packages together:
\begin{verbatim}
DESCRIPTION = “My Package Group”
LICENSE = “MIT”
LIC_FILES_CHECKSUM = “file://<licfile>;md5=<chksum>
inherit packagegroup
PROVIDES = “${PACKAGES}”
PACKAGES = “packagegroup-mypkg-apps packagegroup-mypkg-tools”
RDEPENDS_packagegroup-mypkg-apps = “sqlite3 python-core python-sqlite3”
RDEPENDS_pacakgegroup-mypkg-tools = “sudo gzip tar”
\end{verbatim}
it can be used, to simplify image definitions
\end{frame}

\begin{frame}[fragile]
\frametitle{minimal distribution}
distros are defined in a layer, e.g.

meta-linutronix/conf/distro/mini.conf:
\begin{verbatim}
meta-mini/conf/distro/mini.conf:
DISTRO = "mini"
DISTRO_NAME = "mini 1.0 (for foo devices)"
DISTRO_VERSION = "1.0"
DISTRO_CODENAME = "mal"
\end{verbatim}
\end{frame}
\begin{frame}[fragile]
\begin{verbatim}
SDK_VENDOR = "-linutronix"
SDK_VERSION := "${@'${DISTRO_VERSION}'}"
SDK_NAME = "${DISTRO}-${TCLIBC}-${SDK_ARCH}-${IMAGE_BASENAME}-${TUNE_PKGARCH}"
SDKPATH = "/opt/${DISTRO}/${SDK_VERSION}"
\end{verbatim}
\end{frame}
\begin{frame}[fragile]
\begin{verbatim}
MAINTAINER = "Manuel Traut <manut@linutronix.de>"
TARGET_VENDOR = "-linutronix"
LOCALCONF_VERSION = "1"
LAYER_CONF_VERSION ?= "6"
DISTRO_FEATURES ?= "opengl ${DISTRO_FEATURES_DEFAULT} ${DISTRO_FEATURES_LIBC}"
DISTRO_FEATURES_append = " systemd"
TCLIBCAPPEND = ""
\end{verbatim}
\end{frame}
\begin{frame}[fragile]
\begin{verbatim}
PREMIRRORS ??= "\
bzr://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n \
cvs://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n \
git://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n \
hg://.*/.*    http://downloads.yoctoproject.org/mirror/sources/ \n \
osc://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n \
p4://.*/.*    http://downloads.yoctoproject.org/mirror/sources/ \n \
svk://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n \
svn://.*/.*   http://downloads.yoctoproject.org/mirror/sources/ \n"
\end{verbatim}
\end{frame}
\begin{frame}[fragile]
\begin{verbatim}
MIRRORS =+ "\
ftp://.*/.*      http://downloads.yoctoproject.org/mirror/sources/ \n \
http://.*/.*     http://downloads.yoctoproject.org/mirror/sources/ \n \
https://.*/.*    http://downloads.yoctoproject.org/mirror/sources/ \n"

CONNECTIVITY_CHECK_URIS ?= " \
             https://eula-downloads.yoctoproject.org/index.php \
             http://bugzilla.yoctoproject.org/report.cgi"
\end{verbatim}
\end{frame}
\begin{frame}[fragile]
\begin{verbatim}
SANITY_TESTED_DISTROS ?= " \
            Ubuntu-14.04 \n \
            Debian-7.0 \n \
            Debian-7.1 \n \
            Debian-7.2 \n \
            Debian-7.3 \n \
            Debian-7.4 \n \
            "

BB_SIGNATURE_HANDLER ?= 'OEBasicHash'
OELAYOUT_ABI = "8"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{add distro to git repo}
\begin{verbatim}
poky/meta-mini % git add conf/distro/mini.conf
poky/meta-mini % git commit -sam 'add mini distro'
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{use mini distro}
edit DISTRO var in conf/local.conf
\begin{verbatim}
DISTRO ?= "mini"
\end{verbatim}
\end{frame}

\subsection{Creating images}
\begin{frame}[fragile]
\frametitle{based on core-image class}
build image with ssh support
\begin{verbatim}
poky/build-ti % bitbake-layers show-recipes | grep ssh
Parsing recipes..done.
libssh:
openssh:
packagegroup-core-ssh-dropbear:
packagegroup-core-ssh-openssh:
\end{verbatim}
\pause
create the file
'meta-mini/recipes-bsp/mini-image/mini-image.bb'
\begin{verbatim}
IMAGE_INSTALL += "openssh"
inherit core-image
\end{verbatim}
\pause
to build the image, use:
\begin{verbatim}
poky/build-ti % bitbake mini-image
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{first errors and warnings}
\begin{verbatim}
recommended that you use a tested distribution.
ERROR:  OE-core's config sanity checker detected a potential
        misconfiguration. Either fix the cause of this error or
        at your own risk disable the checker see sanity.conf).
Following is the list of potential problems / advisories:

libsdl-native is set to be ASSUME_PROVIDED but sdl-config can't be
found in PATH. Please either install it, or configure qemu not to
require sdl.
ERROR: Execution of event handler 'check_sanity_eventhandler' failed
ERROR: Command execution failed: Exited with 1
\end{verbatim}
\end{frame}
\begin{frame}[fragile]

	\frametitle{disable sdl support in qemu}
edit conf/local.conf:
\begin{verbatim}
# PACKAGECONFIG_pn-qemu-native = "sdl"
# PACKAGECONFIG_pn-nativesdk-qemu = "sdl"
# ASSUME_PROVIDED += "libsdl-native"
\end{verbatim}
\end{frame}

\subsection{Machines}
\begin{frame}[fragile]
\frametitle{create a beaglebone-black machine config}
create the file 'meta-mini/conf/machine/beaglebone-black.conf':
\begin{verbatim}
#@TYPE: Machine
#@NAME: BeagleBone Black
#@DESCRIPTION: Machine configuration for the http://beagleboard.org/bone board 

require conf/machine/include/ti33x.inc

IMAGE_FSTYPES += "ext3 tar.gz"
EXTRA_IMAGEDEPENDS += "u-boot"
SERIAL_CONSOLE = "115200 ttyO0"

SDCARD_ROOTFS ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3"

SPL_BINARY = "MLO"
UBOOT_SUFFIX = "img"
UBOOT_MACHINE = "am335x_boneblack_config"
UBOOT_ENTRYPOINT = "0x80008000"
UBOOT_LOADADDRESS = "0x80008000"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{user and group configuration}
use this in an image recipe:
\begin{verbatim}
inherit extrausers
EXTRA_USERS_PARAMS = "\
    useradd -p '' tester; \
    groupadd developers; \
    userdel nobody; \
    groupdel -g video; \
    groupmod -g 1020 developers; \
    usermod -s /bin/sh tester; \
    "
\end{verbatim}
or the useradd class, for an example see useradd-example.bb
\end{frame}

\begin{frame}[fragile]
\frametitle{external sources}
e.g. for a heavily customized kernel
\begin{itemize}
\item kernel source directory on the development machine
\pause
\item inherit externalsrc class
\pause
\item set EXTERNALSRC variable to point to your external source code
\end{itemize}

this local.conf extension:
\begin{verbatim}
INHERIT += "externalsrc"
EXTERNALSRC_pn-myrecipe = "/some/path/to/your/source/tree"
\end{verbatim}
overrides the SOURCE\_URI of pn-myrecipe.bb
\end{frame}

\begin{frame}[fragile]
\frametitle{blacklist packages}
To blacklist a package, inherit the blacklist.bbclass globally and set
PNBLACKLIST for each recipe you wish to blacklist.


Specify the PN value as a variable flag (varflag) and provide a reason,
which is reported, if the package is requested to be built as the value:
\begin{verbatim}
INHERIT += "blacklist"
PNBLACKLIST[exoticware] = "Not supported by our organization."
\end{verbatim}
\end{frame}

\subsection{Writing recipes}
\begin{frame}[fragile]
\frametitle{adding a kernel}
create the file 'meta-mini/recipes-bsp/linux-vanilla/linux-vanilla\_3.16.1.bb':
\begin{verbatim}
SECTION = "kernel"
DESCRIPTION = "Linux vanilla kernel"
LICENSE = "GPLv2"
KERNEL_IMAGETYPE = "uImage"

inherit kernel
require recipes-kernel/linux/linux-dtb.inc
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{adding a kernel \#2}
\begin{verbatim}
COMPATILBE_MACHINE_beaglebone-black = "beaglebone-black"
KERNEL_DEVICETREE_beaglebone-black = \
"arch/arm/boot/dts/am335x-boneblack.dts"

S = "${WORKDIR}/linux-${PV}"
https://www.kernel.org/pub/linux/kernel/v3.x/linux-${PV}.tar.xz \
file://defconfig \
"

SRC_URI[md5sum] = "???"
SRC_URI[sha256sum] = "???"

KERNEL_EXTRA_ARGS += "LOADADDR=${UBOOT_ENTRYPOINT}"

do_configure_prepend() {
	cp '${WORKDIR}/defconfig' '${S}/.config'
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{adding a defconfig}
copy your .config file to
'meta-mini/recipes-bsp/linux-vanilla/files/beaglebone-black/defconfig'
\end{frame}

\begin{frame}[fragile]
\frametitle{using a specific kernel}
add
\begin{verbatim}
PREFERRED_PROVIDER_virtual/kernel = "linux-vanilla"
\end{verbatim}
to meta-mini/machine/beaglebone-black.conf
\end{frame}

\begin{frame}[fragile]
\frametitle{Providers}
\begin{verbatim}
--8<- meta/classos/kernel.bbclass --
PROVIDES += "virtual/kernel"
--8<--------------------------------
\end{verbatim}

PREFERRED\_PROVIDER\_virtual/kernel = "linux-yocto"


\pause
\vspace{2em}
also a preferred version can be set:

PREFERRED\_VERSION\_virtual/kernel = "3.18.5"
\end{frame}

\begin{frame}
\frametitle{Preferences}
\begin{itemize}
\item by default, files have a preference of "0"
\pause
\item setting DEFAULT\_PREFERENCE to "-1" makes the recipe unlikely to be used
	unless it is explicitly referenced.
\pause
\item setting DEFAULT\_PREFERENCE to "1" makes it likely the recipe is used
\pause
\item PREFERRED\_VERSION overrides any DEFAULT\_PREFERENCE setting
\end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{using a specific bootloader}
add
\begin{verbatim}
PREFERRED_PROVIDER_virtual/bootloader = "u-boot"
PREFERRED_PROVIDER_virtual/u-boot = "u-boot"
\end{verbatim}
to meta-mini/machine/beaglebone-black.conf
\end{frame}

\subsection{generate a sdcard image}
\begin{frame}[fragile]
\frametitle{sdcard generation}
create the file: 'meta-mini/classes/image\_sdcard.bbclass':
\begin{verbatim}
inherit image_types

IMAGE_BOOTLOADER ?= "u-boot"

# Handle u-boot suffixes
UBOOT_SUFFIX ?= "bin"
UBOOT_PADDING ?= "0"
UBOOT_SUFFIX_SDCARD ?= "${UBOOT_SUFFIX}"

# Linux bootstream
IMAGE_DEPENDS_linux.sb = "virtual/kernel:do_deploy"

# Boot partition volume id
BOOTDD_VOLUME_ID ?= "Boot ${MACHINE}"
# Boot partition size [in KiB]
BOOT_SPACE ?= "8192"
# Set alignment to 4MB [in KiB]
IMAGE_ROOTFS_ALIGNMENT = "4096"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{sdcard generation \#2}
\begin{verbatim}
IMAGE_DEPENDS_sdcard = "parted-native:do_populate_sysroot \
  dosfstools-native:do_populate_sysroot \
  mtools-native:do_populate_sysroot \
  virtual/kernel:do_deploy \
  ${@d.getVar('IMAGE_BOOTLOADER', True) and \
    'd.getVar('IMAGE_BOOTLOADER', True) + ':do_deploy' or ''}"

SDCARD = "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.sdcard"
SDCARD_GENERATION_COMMAND_ti33x = "generate_ti_sdcard"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{sdcard generation \#3}
\begin{verbatim}
generate_ti_sdcard () {
  parted -s ${SDCARD} mklabel msdos

  parted -s ${SDCARD} unit KiB mkpart primary fat32 \
   ${IMAGE_ROOTFS_ALIGNMENT} $(expr ${IMAGE_ROOTFS_ALIGNMENT} \+ \
   ${BOOT_SPACE_ALIGNED})

  parted -s ${SDCARD} unit KiB mkpart primary \
   $(expr  ${IMAGE_ROOTFS_ALIGNMENT} \+ ${BOOT_SPACE_ALIGNED}) \
   $(expr ${IMAGE_ROOTFS_ALIGNMENT} \+ ${BOOT_SPACE_ALIGNED} \+ \
     $ROOTFS_SIZE)

  parted -s ${SDCARD} set 1 boot on
  parted ${SDCARD} print

  BOOT_BLOCKS=$(LC_ALL=C parted -s ${SDCARD} unit b print \
    | awk '/ 1 / { print substr($4, 1, length($4 -1)) / 1024 }')

  mkfs.vfat -n "${BOOTDD_VOLUME_ID}" -S 512 -C \
    ${WORKDIR}/boot.img $BOOT_BLOCKS
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{sdcard generation \#4}
\begin{verbatim}
  # copy files to /boot
  mcopy -i ${WORKDIR}/boot.img -s \
    ${DEPLOY_DIR_IMAGE}/MLO-${MACHINE} ::/MLO
  mcopy -i ${WORKDIR}/boot.img -s \
    ${DEPLOY_DIR_IMAGE}/u-boot-${MACHINE}.img ::/u-boot.img
  mmd -i ${WORKDIR}/boot.img  ::/boot
  mcopy -i ${WORKDIR}/boot.img -s \
    ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE}-${MACHINE}.bin \
    ::/boot/${KERNEL_IMAGETYPE}
  mcopy -i ${WORKDIR}/boot.img -s \
    ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE}-am335x-boneblack.dtb \
    ::/boot/am335x-boneblack.dtb
  mcopy -i ${WORKDIR}/boot.img -s ${DEPLOY_DIR_IMAGE}/uEnv.txt \
    ::/uEnv.txt

  # Burn Partition
  dd if=${WORKDIR}/boot.img of=${SDCARD} conv=notrunc seek=1 \
    bs=$(expr ${IMAGE_ROOTFS_ALIGNMENT} \* 1024)
  sync
  dd if=${SDCARD_ROOTFS} of=${SDCARD} conv=notrunc seek=1 \
    bs=$(expr ${BOOT_SPACE_ALIGNED} \* 1024 + \
         ${IMAGE_ROOTFS_ALIGNMENT} \* 1024)
  sync
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{sdcard generation \#5}
\begin{verbatim}
IMAGE_CMD_sdcard () {
  if [ -z "${SDCARD_ROOTFS}" ]; then
    bberror "SDCARD_ROOTFS is undefined."
    exit 1
  fi

  # Align boot partition and calculate total SD card image size
  BOOT_SPACE_ALIGNED=$(expr ${BOOT_SPACE} + ${IMAGE_ROOTFS_ALIGNMENT} - 1)
  BOOT_SPACE_ALIGNED=$(expr ${BOOT_SPACE_ALIGNED} - \
    ${BOOT_SPACE_ALIGNED} % ${IMAGE_ROOTFS_ALIGNMENT})
  SDCARD_SIZE=$(expr ${IMAGE_ROOTFS_ALIGNMENT} + \
    ${BOOT_SPACE_ALIGNED} + $ROOTFS_SIZE + ${IMAGE_ROOTFS_ALIGNMENT})

  # Initialize a sparse file
  dd if=/dev/zero of=${SDCARD} bs=1 count=0 \
    seek=$(expr 1024 \* ${SDCARD_SIZE})

  ${SDCARD_GENERATION_COMMAND}
}

# The sdcard requires the rootfs filesystem to be built before using
# it so we must make this dependency explicit.
IMAGE_TYPEDEP_sdcard = "${@d.getVar('SDCARD_ROOTFS', 1).split('.')[-1]}"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{configure machine to use sdcard imagetype}
add the following lines to 'meta-mini/conf/machine/beaglebone-black.conf':
\begin{verbatim}
IMAGE_CLASSES += "image_sdcard"
SDCARD_ROOTFS ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3"
IMAGE_FSTYPES += "sdcard"
\end{verbatim}
\end{frame}

\begin{frame}
\frametitle{adding an own application}
\begin{itemize}
	\item recipe already available? check http://layers.openembedded.org
\pause
	\item look for a similar recipe
\pause
	\item proper bbclass available?
\end{itemize}
on the next slides, we have a look what is useful for very simple applications,
autotools and cmake based projects and qt applications.
\end{frame}

\begin{frame}[fragile]
\frametitle{as simple as posible}
use this folder layout
\begin{verbatim}
poky/meta-mini/recipes-hello % tree
hello
├── files
│   └── hello.c
└── hello.bb
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{as simple as posible \#2}
this is the content of hello.bb
\begin{verbatim}
DESCRIPTION = "Simple helloworld application"
SECTION = "examples"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT; \
  md5=0835ade698e0bcf8506ecda2f7b4f302"
PR = "r0"
SRC_URI = "file://hello.c"
S = "${WORKDIR}"

do_compile() {
  ${CC} hello.c -o hello
}

do_install() {
  install -d ${D}${bindir}
  install -m 0755 hello ${D}${bindir}
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{autools based project}
\begin{verbatim}
├── autohello_1.0.bb
└── files
    └── autohello-1.0.tar.gz
\end{verbatim}
\pause
\begin{verbatim}
DESCRIPTION = "GNU Helloworld application"
SECTION = "examples"
LICENSE = "GPLv2+"
LIC_FILES_CHKSUM = "file://COPYING;md5=d32239bcb673463ab874e80d47fae504"
PR = "r0"
SRC_URI = "file://autohello-${PV}.tar.gz"
SRC_URI[md5sum] = "4bfc9bed4d5d67a266d93e99e5883211"
inherit autotools
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{cmake based project}
\begin{verbatim}
.
├── files
│   └── hellocm-0.1.tar.bz2
└── hellocm_0.1.bb
\end{verbatim}
\pause
\begin{verbatim}
DESCRIPTION = "hellocm cmake example"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
SECTION = "examples"
SRC_URI = "file://${BPN}-${PV}.tar.bz2"
inherit cmake

#export EXTRA_OECMAKE = '-DBLUBB="bla"

FILES_{PN} = "${bindir}/hellocm"
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{qt application}
\begin{verbatim}
├── files
│   └── helloqt-1.0.tar.bz2
└── helloqt_1.0.bb
\end{verbatim}
\pause
\begin{verbatim}
DESCRIPTION = "helloqt QT example"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
SECTION = "examples"
SRC_URI = "file://${BPN}-${PV}.tar.bz2"
inherit qt4e
PR = "r4"
do_install() {
        install -d ${D}${bindir}
        install -m 0755 helloqt ${D}${bindir}
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\frametitle{adding a bootscript}
\begin{itemize}
	\item add 'systemd' to DISTRO\_FEATURES
\pause
	\item inherit from systemd.bbclass
\pause
	\item your package needs to set SYSTEMD\_SERVICE variable; e.g.
		\begin{verbatim}
SYSTEMD_SERVICE_${PN} = "connman.service"
		\end{verbatim}
\pause
	\item to disable the service, set  SYSTEMD\_AUTO\_ENABLE to 'disable'
\end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{user and group configuration}
use this in an image recipe:
\begin{verbatim}
inherit extrausers
EXTRA_USERS_PARAMS = "\
    useradd -p '' tester; \
    groupadd developers; \
    userdel nobody; \
    groupdel -g video; \
    groupmod -g 1020 developers; \
    usermod -s /bin/sh tester; \
    "
\end{verbatim}
or the useradd class, for an example see useradd-example.bb
\end{frame}

\begin{frame}[fragile]
\frametitle{external sources}
e.g. for a heavily customized kernel
\begin{itemize}
\item kernel source directory on the development machine
\item inherit externalsrc class
\item set EXTERNALSRC variable to point to your external source code
\end{itemize}

this local.conf extension:
\begin{verbatim}
INHERIT += "externalsrc"
EXTERNALSRC_pn-myrecipe = "/some/path/to/your/source/tree"
\end{verbatim}
overrides the SOURCE\_URI of pn-myrecipe.bb
\end{frame}

\begin{frame}[fragile]
\frametitle{blacklist packages}
To blacklist a package, inherit the blacklist.bbclass globally and set
PNBLACKLIST for each recipe you wish to blacklist.


Specify the PN value as a variable flag (varflag) and provide a reason,
which is reported, if the package is requested to be built as the value:
\begin{verbatim}
INHERIT += "blacklist"
PNBLACKLIST[exoticware] = "Not supported by our organization."
\end{verbatim}

\subsection{Resume}
\begin{frame}
	\begin{itemize}
		\item Yocto is a huge collection of tools
		\pause
		\item Bitbake can be used to create Images
		\pause
		\item The quality of the Images depend on the maintainance of the Layers
		\pause
		\item Only build your own distribution if you really need to!
	\end{itemize}
\end{frame}

\input{tailpres}