This is a complete EXAMPLE PROJECT WITH GUIDE for creating a YOCTO build for RASPBERRY PI (RPI).

The main target is RPI4, but with minimal edits it shall support any Yocto-supported RPI with HDMI.

The project is up-to-date with the Detailed Manual pdf document, titled:
"Manual for Custom Yocto-based minimal Linux Image for Raspberry Pi.pdf"

This document and the project have several purposes:

1.) Describing how our demo project works, so that you can use it for your needs - from the 
build to the final usage on the RPI4B (Raspberry PI 4B). If you like it, we will be happy 
to get a star on GitHub :). You can also use the project for most RPI boards before 4B! 
Model 5 is not yet supported by Yocto. The project can also be built for QEMU, for which
you don’t need HW. 

2.) It is also a primer for anyone willing to step into Yocto to make his own build, for 
ANY of the already supported by Yocto HW platforms.

3.) In addition, it presents how this can be done on Manjaro, as it is not an officially 
Yocto-supported host distribution. With a few simple installations we can build Yocto 
projects flawlessly on Manjaro. We want to contribute by adding one more distribution to 
those which are officially approved.

4.) As a next point, it shows what standard SW we have integrated in our image, so that 
you know for what you can use our image. 
5.) The project also presents how one can integrate a GUI application. In our case it is an 
IMGUI demo, based on OpenGL with GLFW2 and the X11 environment.
6.) Finally it briefly mentions Work orders / Project development for clients, Partnerships, 
Change requests, contributions, and fixes.

Our image also includes a set of BusyBox GNU tools, SSH connection, HDMI setup, and WiFi 
connection script (which saves its values between reboots), which are all described.

The document contains many sections, some of which are:
1. Non-tech Introduction _________________________________________________________________4
2. Yocto in 5 minutes from a technical perspective _______________________________________4
3. What do you need on Manjaro to run a Yocto build ______________________________________7
4. The RPI 4B Platform and the Display ___________________________________________________7
5. Yocto and Raspberry PI ________________________________________________________________8
7. Yocto versions and information, how to know what kernel version do we build from Poky _9
8. The BitBake build steps _______________________________________________________________10
9. Fetching the project and building it yourself - super easy, with only a few commands __12
10. Our project structure and bitbake basics _____________________________________________14

11. Starting the board ___________________________________________________________________21
Using halt and reboot ____________________________________________________________________22
Connecting via SSH _______________________________________________________________________22

12. Networking and starting the WiFi _____________________________________________________23
13. The SW provided by our image _________________________________________________________23
BusyBox, Shell, Init system, Libraries, X11, Avahi, Dropbear SSH, wpa_supplicant,...
Looking for other modules, present or not. _______________________________________________26
Logs, Kernel, Editor, Clock

16. Processor, CPU Speed, and HW specification ___________________________________________26
17. Adding a module ______________________________________________________________________27
14. IMGUI DEMO ___________________________________________________________________________27
15. Changing for different HW ____________________________________________________________28

16. Important Yocto Links ________________________________________________________________28

17. License, development, and contribution _______________________________________________29
18. Change Requests, Bugs, Contributions, New Features ___________________________________30
19. Projects and work orders, partnerships _______________________________________________30
20. Copyright notice

Important prerequisite - it is expected, that you have at least some basic Linux knowledge 
and/or experience (except for the Introduction). If you have none or would like to advance, 
I have written a book, called the Manjaro Linux User Guide, a top up-to-date book to 
learn Linux in 2024! 
It covers all general topics from the installation and graphical environments, through 
available SW, a great Terminal primer, package managers, encryption, Filesystem basics, 
Storage and backup, Networking and Sharing, Firewalls, Systemctl, Services, Shell scripts 
and automation, and others.
12 of its sub-sections are shared for free as articles! 
Take a look here: https://triplehelix-consulting.com/book/.

Dependencies
============

  URI: [email protected]:yoctoproject/poky.git
  branch: kirkstone

  URI: [email protected]:openembedded/meta-openembedded.git
  branch: kirkstone

  URI: [email protected]:agherzan/meta-raspberrypi
  branch: kirkstone  

  URI: [email protected]:AtanasRusevTH/rpiconf-v1
  branch: kirkstone  

Maintainer: Atanas Rusev <atanasr at triplehelix-consulting dot com>

Short instruction
=================

I. The easiest and fully AUTOMATIC way to work with the project
=================================================
1. Download the file /meta-thc/bin/metafetch-v1

2. Create a directory in your home, named, for example, yocto-rpi4-thc-v1. 

3. Execute the script with these arguments:

$ ./metafetch-v1 -b <BUILD_DIR> -m <METADATA_DIR>

for the example this would be 

$ ./metafetch-v1 -b ~/yocto-rpi4-thc-v1/build -m ~/yocto-rpi4-thc-v1/metadata

The script will clone all necessary dependencies and apply changes according to your 
local paths in the file ~/yocto-rpi4-thc-v1/build/conf/bblayers.conf

By default the script clones via http, which is slower and may experience interrupts.

The script also supports the git protocol. If you have a local git configuration in ~/.gitconfig, 
it can fetch via the git protocol. 
For this just add "-g" directly after the metafetch-v1 name. More is explained in the 
detailed pdf documentation.

Next navigate to ~/yocto-rpi4-thc-v1/metadata/poky/ and execute:
$ source oe-init-build-env <BUILD_DIR>

For the example this would be:
$ source oe-init-build-env ~/yocto-rpi4-thc-v1/build

Now simply execute
$ bitbake core-image-thc

You will get a .wic file to be copied to the microSD card of your RPI board in:
~/yocto-rpi4-thc-v1/build/tmp/deploy/images/raspberrypi4-64/core-image-thc-raspberrypi4-64.wic

Copy the file with:
$ sudo dd if=/Path-To-File/core-image-thc-raspberrypi4-64.wic of=/dev/<xxx> status=progress

Full details are available in the the Manual pdf.

=================================================
Apart from this:
=================================================

II. Adding the meta-thc layer to your build
=================================================
Run 'bitbake-layers add-layer meta-thc'.

III. Build
=================================================
Run 'bitbake core-image-thc'.

IV. Origin 
=================================================
This is the first stable version of https://github.com/kaloyanski/meta-thc.
I freeze it as the original repository continues to be actively developed (as of Jan 2024).
The documentation for the original repository is located at https://kaloyanski.github.io/meta-thc.
Its updates will happen when Kaloyanski has time to do it.

V. Message
=================================================
If you are interested in this project, we will be glad to know and potentially collaborate. 
In this case, please contact <office at triplehelix-consulting dot com>

You can also write via https://triplehelix-consulting.com/contact/