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yocto Build System

Sep 7, 2019
Apr 22, 2020

IMAGE GALLERY (4)

THE YOCTO PROJECT. IT’S NOT AN EMBEDDED LINUX DISTRIBUTION, IT CREATES A CUSTOM ONE FOR YOU.

yocto
that provides templates, tools and methods to help you create custom Linux-based systems for embedded products regardless of the hardware architecture
Eg: create a nodejs enabled linux image for raspberrypi
wiki-yocto How_do_I
means 10^24
lets you write OS for newly devloped IoT device like washing machine
SDK
A software development kit (SDK) is a collection of software development tools in one installable package
backend, api, frontend in 1 package
specific to a hardware platform and operating system combination

How to configure device tree using yocto

  • linux-yocto kernel (or whichever is being used)
  • dts file in linux-yocto recipe
  • device tree blob (dtb)
  • fdtdump /boot/am335x-boneblack.dtb
  • Getting a property from device tree
    • fdtget /boot/am335x-boneblack.dtb spi0 status
bitbake-layers show-recipes -i kernel -r
  1. Recipies which inherit kernel .bbclass as all kernel recipies should inherit it
  2. List recipe name only
# Configure before devshell else might face SYNCCONFIG error
./tools/run_in_container.sh build ./tools/build/bitbake.sh build/bbb nas.pb.avantys.de:/mnt/nas/data/Projekte/SkySails/os/yocto-thud linux-yocto -c clean
./tools/run_in_container.sh build ./tools/build/bitbake.sh build/bbb nas.pb.avantys.de:/mnt/nas/data/Projekte/SkySails/os/yocto-thud linux-yocto -c configure
./tools/run_in_container.sh build ./tools/build/bitbake.sh build/bbb nas.pb.avantys.de:/mnt/nas/data/Projekte/SkySails/os/yocto-thud linux-yocto -c devshell

make dtbs

List USB devices on linux

lsusb
show you whether the kernel sees usb 3.0 support.
# List block devices
lsblk

dmesg | grep usb
lsusb --tree
blkid
iPXE
is the leading open source network boot firmware.
It provides a full PXE implementation enhanced with additional features such as:
boot from a web server via HTTP
boot from an iSCSI SAN
boot from a Fibre Channel SAN via FCoE
boot from an AoE SAN
boot from a wireless network
boot from a wide-area network
boot from an Infiniband network
control the boot process with a script

Build Linux from scratch!

  • /boot
    • has initramfs and device-tree files
    • makemenu configs
    • grub configs
  • Linux boot in 8 secs to work with LCDs
  • Able to change HDD size for vagrant VB provider VM, mark it as SSD

Bitbake

  • BitBake is a make-like build tool with the special focus of distributions and packages for embedded Linux cross compilation
  • BitBake recipes specify how a particular package is built
  • Recipes consist of the source URL (http, https, ftp, cvs, svn, git, local file system) of the package, dependencies and compile or install options *

Questions

  1. How to change partitions sizes? Extend partitions?
    1. Use fdisk --list /dev/part command
    2. wks File
  2. How to run wic image on virt-manager
  3. How to build ubuntu from scratch using yocto?

Bitbake Recipe

LICENSE
The type of license. This is set to unknown because devtool cannot recognize the old MIT text.
LIC_FILES_CHKSUM
devtool looks in the root of the source folder for a file called LICENSE, and generates a checksum to ensure checkout has been successful.
SRC_URI
The git repo given in the ‘devtool add’ command. This is where the source will be pulled from.
PV
The package version. Usually taken from recipe filename (e.g. bbexample_0.1.bb would automatically set PV = “0.1”)
SRCREV
the git revision to checkout. ${AUTOREV} means HEAD and must be used during app development. It should be set a specific commit before being added to a layer.
S
Where the source can be found after being fetched and unpacked.
inherit autotools
GNU Build System Tools
GNU Autoconf, GNU Automake and GNU lib tool
EXTRA_OECONF
Options to be passed to configure script. In this case it is empty, so is not necessary.
DEPENDS
means a build-time dependency
RDEPENDS
Runtime dependency

https://lists.yoctoproject.org/pipermail/yocto/2013-August/015811.html

Automatically create yocto recipes from using devtool

Caution - Do not use recipe name followed by - (hyphen), use underscore for versioning instead

Yocto

  • linux-yocto recipe layer has actual linux kernel versions

Devtools yocto recipe

  • hexdump utility is part of bsdmainutils package. Alternatively, you could use xxd from the xxd package
  • Meta Recipies-devtools1
  • Search for prebuilt recipies

How to installl python packages on yocto?

# Show layer dependencies
bitbake-layers layerindex-show-depends meta-python
# Add layer inside poky
bitbake-layers layerindex-fetch meta-oe

How to update yocto build system?

  • MAJOR.Minor.patch
  • Yocto release process, every 6 months
  • Poky is the reference distro the Yocto Project releases with each Yocto Project release. These releases are named releases (danny, dora, dylan, edison, etc.) as well as numbered utilizing Major.minor.patch numbering. -

Yocto kernels

devtool modify linux-yocto

# Add Recipies
IMAGE_INSTALL_append = "gtk+3"
EXTRA_IMAGE_FEATURES += " package-management "

Efficient

  1. Build dashboards - toaster
  2. Error Reporting - Dashboards

Cool Features

Footnotes

  1. https://git.yoctoproject.org/cgit.cgi/poky/plain/meta/recipes-devtools/ [return]