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

​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

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