meta-pipi

meta-pipi is a Yocto example project initiated by Pascal Linder. It is used to try out different features on a Raspberry Pi 4 board.

Raspberry Pi 4

Refer to the doc/ folder for documentation about the embedded target.

Serial Console

A serial console is used to interact directly with the Raspberry Pi. Therefore, an FTDI cable is required that converts UART to USB. Following the cable pinout that, together with the schematics, is used to connect the serial console.

1. GND (black)
2. CTS (brown)
3. Vcc (red)
4. TxD (orange)
5. RxD (yellow)
6. RTS (green)

PiPi Distribution and Image

PiPi is a pun from Raspberry Pi and the usual pre- or postfix in Pascal's projects. The image provides a root user password (z2P%b!Sy) that can be used when connecting over the serial console.

As the RootFS is read-only by default, following command can be used to make it writable:

mount -o remount,rw /

Build

As the project builds upon kas, only a single command is required to create an image if the dependent tools are installed.

kas build kas/pipi.yml

It is also possible to build the image in a Docker container containing all the tools with following command. Make sure to allocate enough resources for Docker.

./scripts/build-in-container.sh

In order to have access to the usual bitbake commands, type something similar to one of the following into your console.

kas shell kas/pipi.yml
kas shell kas/pipi.yml -c 'bitbake -e pipi-image | grep ^IMAGE_INSTALL'

# recipe examples: u-boot, virtual/kernel
kas shell kas/pipi.yml -c 'bitbake -c menuconfig <recipe>'  # tmux must be installed
kas shell kas/pipi.yml -c 'bitbake -c devshell <recipe>'

Flash

The built image can be flashed to an SD card with following command:

./scripts/flash-sd-card.sh pipi-image <sd-path>

Emulation

With the following command it is possible to emulate the system on your host computer using Quick EMUlation (QEMU). To exit and stop the command line, press ctrl-a and then x on your keyboard.

./scripts/run-in-container.sh

Yocto

Yocto is a project that helps create custom Linux distributions by providing tools and templates. It uses a recipe-based system to define and build the different components of the distribution.

Deployment folder variables for use in recipes are defined under poky/meta/conf/bitbake.conf.