How to create a custom yocto meta layer

Introduction

This wiki will provide a detailed guide on how to create a custom Yocto meta-layer.

Create Base Meta-Layer

This section contains steps to create the base custom meta-layer. After completion, the custom base meta-layer will contain the following parts:

• Custom layer configuration
• Custom distro configuration
• Custom machine
• Custom config template files
• Custom image recipe

Step 1. Add base layer.conf file

The layer configuration file provides Yocto with the configuration for the custom meta-layer. It shall be stored in a directory called conf inside the base meta-layer directory, and it shall be named layer.conf. According to the Yocto documentation it is recommended to start from an existing layer.conf file from a different meta-layer and change it according to the custom requirements.

For instance, here is an example of how the directory structure should look after creating the layer.conf file.

meta-proventusnova/
├── conf
│   └── layer.conf
└── README.md

An example layer.conf file based on NVIDIA OE4T tegra_demo_distro is shown in the following code snipped.

BBPATH =. "${LAYERDIR}:"
BBFILES += "${LAYERDIR}/recipes-*/*/*.bb ${LAYERDIR}/recipes-*/*/*.bbappend"
BBFILES_DYNAMIC += "swupdate:${LAYERDIR}/dynamic-layers/meta-swupdate/recipes-*/*/*.bb \
                    swupdate:${LAYERDIR}/dynamic-layers/meta-swupdate/recipes-*/*/*.bbappend"

BBFILE_COLLECTIONS += "proventusnova"
BBFILE_PATTERN_proventusnova = "^${LAYERDIR}/"
BBFILE_PRIORITY_proventusnova = "50"

LAYERVERSION_proventusnova = "4"
LAYERSERIES_COMPAT_proventusnova = "scarthgap"

# This is used by the tegra-distro-sanity bbclass
# to identify the distro layer directory during
# bblayers checks.
TD_DISTRO_LAYERDIR = "${LAYERDIR}"