Yocto Linux Integration

The Yocto Project provides a flexible framework for creating custom embedded Linux distributions tailored for EV charging applications. EVerest includes a meta-layer for seamless integration.

Overview

The meta-everest layer provides BitBake recipes and configurations for building EVerest and its dependencies into embedded Linux images.

Repository: The meta-everest layer is located in yocto/ directory of the EVerest Core repository.Supported Releases:

Kirkstone (LTS)
Scarthgap (Latest)

Prerequisites

Development Host Requirements

# Ubuntu/Debian
sudo apt-get install gawk wget git diffstat unzip texinfo \
  gcc build-essential chrpath socat cpio python3 python3-pip \
  python3-pexpect xz-utils debianutils iputils-ping python3-git \
  python3-jinja2 libegl1-mesa libsdl1.2-dev xterm python3-subunit \
  mesa-common-dev zstd liblz4-tool

# Fedora/RHEL
sudo dnf install gawk make wget tar bzip2 gzip python3 unzip \
  perl patch diffutils diffstat git cpp gcc gcc-c++ glibc-devel \
  texinfo chrpath ccache perl-Data-Dumper perl-Text-ParseWords \
  perl-Thread-Queue python3-pip xz which SDL-devel xterm zstd lz4

Disk Space Requirements

Minimum: 50 GB free disk space
Recommended: 100 GB+ for multiple builds and sstate cache

Setting Up Yocto Build Environment

Clone Poky and Layers

Initialize Yocto workspace

mkdir ~/yocto-everest
cd ~/yocto-everest

# Clone Poky (Yocto reference distribution)
git clone -b kirkstone git://git.yoctoproject.org/poky.git
cd poky

Add meta-everest layer

# Copy or symlink meta-everest from EVerest source
ln -s /path/to/everest-core/yocto/kirkstone/meta-everest \
  ~/yocto-everest/poky/meta-everest

Add additional required layers

cd ~/yocto-everest/poky

# meta-openembedded (for additional dependencies)
git clone -b kirkstone \
  git://git.openembedded.org/meta-openembedded

Configure Build

# Source the build environment
source oe-init-build-env build-everest

# This creates and enters the build directory
cd ~/yocto-everest/poky/build-everest

Edit `conf/bblayers.conf`

Add meta-everest and dependencies:

BBLAYERS ?= " \
  /home/user/yocto-everest/poky/meta \
  /home/user/yocto-everest/poky/meta-poky \
  /home/user/yocto-everest/poky/meta-yocto-bsp \
  /home/user/yocto-everest/poky/meta-openembedded/meta-oe \
  /home/user/yocto-everest/poky/meta-openembedded/meta-python \
  /home/user/yocto-everest/poky/meta-openembedded/meta-networking \
  /home/user/yocto-everest/poky/meta-everest \
"

Edit `conf/local.conf`

# Set target machine (example for generic x86-64)
MACHINE = "genericx86-64"

# Or for ARM-based platforms:
# MACHINE = "raspberrypi4-64"
# MACHINE = "phyboard-electra-imx8mp-3"

# Parallelization (adjust to your CPU)
BB_NUMBER_THREADS = "8"
PARALLEL_MAKE = "-j 8"

# Disk space monitoring
BB_DISKMON_DIRS = "STOPTASKS,${TMPDIR},1G,100K STOPTASKS,${DL_DIR},1G,100K"

# Add EVerest to image
IMAGE_INSTALL:append = " everest-core"

# Optional: Enable systemd
DISTRO_FEATURES:append = " systemd"
VIRTUAL-RUNTIME_init_manager = "systemd"
DISTRO_FEATURES_BACKFILL_CONSIDERED = "sysvinit"

Building EVerest Images

Build Core Image

# Build a minimal image with EVerest
bitbake core-image-minimal

# Or build a more complete image
bitbake core-image-full-cmdline

The first build will take 2-6 hours depending on your hardware and network speed, as it downloads and compiles all dependencies from source.

Build EVerest Package Only

To rebuild just EVerest after changes:

# Clean previous build
bitbake -c cleansstate everest-core

# Rebuild
bitbake everest-core

meta-everest Layer Structure

The meta-everest layer includes recipes for EVerest and its dependencies:

meta-everest/
├── recipes-everest/
│   ├── everest-core/        # Main EVerest package
│   ├── everest-framework/   # EVerest framework library
│   ├── libocpp/            # OCPP library
│   └── libevse-security/   # Security library
├── recipes-backports/
│   ├── nlohmann-json/      # JSON library
│   ├── libwebsockets/      # WebSocket support
│   ├── fmt/                # Formatting library
│   └── date/               # Date/time library
└── classes/
    └── everest_version_file.bbclass

Key Recipes

EVerest Core Recipe

The main recipe builds EVerest from source with all dependencies:

# From recipes-everest/everest-core/everest-core_*.bb
DESCRIPTION = "EVerest - EV Charging Station Framework"
LICENSE = "Apache-2.0"

DEPENDS = " \
    everest-framework \
    libocpp \
    libevse-security \
    nlohmann-json \
    fmt \
    date \
    websocketpp \
    libwebsockets \
"

inherit cmake systemd

Version Tracking

The everest_version_file class generates a JSON file with package versions installed on the system.

Enable Version File

Add to your image recipe:

inherit everest_version_file

This creates /etc/everest/everest_release.json:

{
  "everest-core": "2024.3.0",
  "libocpp": "0.16.0",
  "kernel": "5.15.92",
  "systemd": "250.5"
}

Add Custom Packages to Version File

In local.conf:

EVEREST_RELEASE_PACKAGES += "systemd tcpdump mosquitto"

The version file is useful for debugging and tracking deployed software versions in production charging stations.

Deployment to Embedded Systems

Flash Image to Target

SD Card / eMMC

# Locate the built image
cd tmp/deploy/images/${MACHINE}/

# Flash to SD card (replace /dev/sdX with your device)
sudo dd if=core-image-minimal-${MACHINE}.wic \
  of=/dev/sdX bs=4M status=progress
sudo sync

Network Boot (TFTP/NFS)

For development:

# Extract rootfs
sudo tar -xzf core-image-minimal-${MACHINE}.tar.gz \
  -C /srv/nfs/everest/

# Configure TFTP boot on target bootloader

First Boot Configuration

Network Setup

Configure static IP or DHCP in /etc/systemd/network/

Verify EVerest Installation

systemctl status everest-core
/usr/bin/manager --help

Check System Resources

free -h
df -h
dmesg | grep -i error

Platform-Specific Integration

PHYTEC SoMs

PHYTEC’s ampliPHY distribution provides:

Pre-configured BSP for PHYTEC hardware
RAUC update support built-in
Secure boot configurations

# Use ampliphy-rauc or ampliphy-secure distributions
DISTRO = "ampliphy-rauc"

Raspberry Pi

For testing and development:

MACHINE = "raspberrypi4-64"

# Enable UART for debugging
ENABLE_UART = "1"

Add to config.txt:

enable_uart=1
dtoverlay=disable-bt

Custom Image Recipes

Create a custom image recipe for your charging station:

# meta-custom/recipes-core/images/everest-charger-image.bb
require recipes-core/images/core-image-minimal.bb

DESCRIPTION = "Custom EVerest Charging Station Image"

IMAGE_FEATURES += "ssh-server-dropbear"

IMAGE_INSTALL += " \
    everest-core \
    mosquitto \
    node-red \
    tcpdump \
    htop \
    vim \
"

# Add version tracking
inherit everest_version_file

# Enable read-only rootfs
IMAGE_FEATURES += "read-only-rootfs"

Optimization for Production

Minimize Image Size

# Remove development tools
EXTRA_IMAGE_FEATURES:remove = "tools-debug tools-sdk dev-pkgs"

# Use smaller C library
TCLIBCAPPEND = "musl"

# Strip debug symbols
INHIBIT_PACKAGE_DEBUG_SPLIT = "1"

Security Hardening

# Enable security flags
EXTRA_IMAGE_FEATURES += "seccomp apparmor"

# Read-only root filesystem
IMAGE_FEATURES += "read-only-rootfs"

# Disable root login
EXTRA_IMAGE_FEATURES:remove = "allow-root-login"

Development Workflow

Iterative Development

# 1. Make changes to EVerest source
vim /path/to/everest-core/modules/...

# 2. Tell Yocto to use local source
# Add to local.conf:
EVEREST_CORE_SRC = "/path/to/everest-core"

# 3. Rebuild
bitbake -c compile -f everest-core
bitbake -c deploy everest-core

# 4. Update running target
scp tmp/deploy/rpm/.../everest-core*.rpm root@target:/tmp/
ssh root@target 'rpm -Uvh --force /tmp/everest-core*.rpm'

SDK for Cross-Compilation

Generate SDK for development:

bitbake core-image-minimal -c populate_sdk

# Install SDK
./tmp/deploy/sdk/poky-glibc-x86_64-core-image-minimal-*-toolchain-*.sh

# Source environment
source /opt/poky/*/environment-setup-*

# Now you can cross-compile directly
$CC myapp.c -o myapp

Troubleshooting

Build Failures

Fetch failures

# Clear download cache
rm -rf downloads/

# Or set alternative mirror
PREMIRRORS:prepend = "git://.*/.* http://downloads.yoctoproject.org/mirror/sources/"

Disk space errors

# Clean old builds
bitbake -c cleansstate everest-core

# Remove tmp directory
rm -rf tmp/

Dependency conflicts

# Check recipe dependencies
bitbake -g everest-core
cat pn-depends.dot

Runtime Issues

# Check system logs
journalctl -u everest-core -f

# Verify library dependencies
ldd /usr/bin/manager

# Check configuration
/usr/bin/manager --check config.yaml

Next Steps

OTA Updates

Implement RAUC for safe updates

Configuration

Configure your charging station

Security

Set up TPM and certificates

Hardware Setup

Connect and configure peripherals

Get Started

Core Concepts

Modules

Development

Deployment

Community

​Overview

​Prerequisites

​Development Host Requirements

​Disk Space Requirements

​Setting Up Yocto Build Environment

​Clone Poky and Layers

​Configure Build

​Edit conf/bblayers.conf

​Edit conf/local.conf

​Building EVerest Images

​Build Core Image

​Build EVerest Package Only

​meta-everest Layer Structure

​Key Recipes

​EVerest Core Recipe

​Version Tracking

​Enable Version File

​Add Custom Packages to Version File

​Deployment to Embedded Systems

​Flash Image to Target

​SD Card / eMMC

​Network Boot (TFTP/NFS)

​First Boot Configuration

​Platform-Specific Integration

​PHYTEC SoMs

​Raspberry Pi

​Custom Image Recipes

​Optimization for Production

​Minimize Image Size

​Security Hardening

​Development Workflow

​Iterative Development

​SDK for Cross-Compilation

​Troubleshooting

​Build Failures

​Runtime Issues

​Next Steps

OTA Updates

Configuration

Security

Hardware Setup

Build docs developers (and LLMs) love

Overview

Prerequisites

Development Host Requirements

Disk Space Requirements

Setting Up Yocto Build Environment

Clone Poky and Layers

Configure Build

Edit `conf/bblayers.conf`

Edit `conf/local.conf`

Building EVerest Images

Build Core Image

Build EVerest Package Only

meta-everest Layer Structure

Key Recipes

EVerest Core Recipe

Version Tracking

Enable Version File

Add Custom Packages to Version File

Deployment to Embedded Systems

Flash Image to Target

SD Card / eMMC

Network Boot (TFTP/NFS)

First Boot Configuration

Platform-Specific Integration

PHYTEC SoMs

Raspberry Pi

Custom Image Recipes

Optimization for Production

Minimize Image Size

Security Hardening

Development Workflow

Iterative Development

SDK for Cross-Compilation

Troubleshooting

Build Failures

Runtime Issues

Next Steps