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Multiconfig Design

One workspace, one sync, all machines.

Architecture

~/yocto-auton/                          ← Single workspace
├── sources/
│   ├── poky/                           ← Yocto core (Scarthgap LTS)
│   ├── meta-openembedded/              ← OE layers
│   ├── meta-raspberrypi/               ← RPi5 BSP
│   ├── meta-ti/                        ← BeagleBone BSP
│   └── meta-auton-repo/                ← This repo
│       ├── auton-init-build-env        ← THE setup script
│       └── meta-auton/                 ← Custom layer (distro + machines + kernel)
├── build/
│   ├── conf/
│   │   ├── local.conf                  ← Shared config + BBMULTICONFIG
│   │   ├── bblayers.conf               ← All layers (BSP auto-detected)
│   │   └── multiconfig/
│   │       ├── qemu-arm64.conf         ← MACHINE=qemu-arm64, separate TMPDIR
│   │       ├── beaglebone-black.conf   ← MACHINE=beaglebone-black
│   │       └── raspberrypi5.conf       ← MACHINE=raspberrypi5
│   ├── tmp-qemu-arm64/                 ← Build output for QEMU
│   ├── tmp-beaglebone-black/           ← Build output for BBB
│   └── tmp-raspberrypi5/               ← Build output for RPi5
├── downloads/                          ← Shared source tarballs
└── sstate-cache/                       ← Shared build cache

How It Works

  1. One manifest (default.xml) syncs ALL BSP layers
  2. One distro (auton.conf) shared across all machines
  3. Multiconfig lets bitbake build any machine without re-sourcing:
  4. BBMULTICONFIG = "qemu-arm64 beaglebone-black raspberrypi5"
  5. Each multiconfig file sets MACHINE and a separate TMPDIR
  6. BSP auto-detection: bblayers.conf only adds meta-ti or meta-raspberrypi if they exist after sync

What Changed

Before After
3 separate workspaces 1 workspace
3 separate repo sync 1 repo sync
Per-machine manifests required Single default.xml
Re-source env to switch machine bitbake mc:<machine>:image
Separate downloads/sstate Shared (saves 10-20GB)

Build Matrix

Command What it builds
bitbake auton-image-minimal Default machine (from env selection)
bitbake mc:qemu-arm64:auton-image-minimal QEMU AArch64
bitbake mc:beaglebone-black:auton-image-minimal BeagleBone Black
bitbake mc:raspberrypi5:auton-image-minimal Raspberry Pi 5
bitbake mc:qemu-arm64:core-image-minimal Stock Yocto on QEMU (for testing)

Yocto Release

  • Baseline: Scarthgap (5.0 LTS, April 2024)
  • Layer compat: scarthgap styhead
  • Kernel: linux-auton 6.12 LTS (or fallback to linux-yocto)