meta-tegra BSP Layer

The meta-tegra layer is an OpenEmbedded/Yocto Board Support Package (BSP) layer designed for NVIDIA Jetson Modules. It provides the necessary recipes and configurations to build Yocto-based Linux distributions for specific Jetson hardware.

Supported Hardware:

• Jetson AGX Thor development kit
• Jetson AGX Orin development kit
• Jetson Orin NX 16GB (p3767-0000) in Xavier NX (p3509) carrier
• Jetson Orin NX 16GB (p3767-0000) in Orin Nano (p3768) carrier
• Jetson Orin Nano development kit
• Jetson AGX Orin Industrial 64GB (P3701-0008) in Orin AGX (P3737) carrier

Compatibility Requirements:

• Jetson Linux release: R39.2.0
• JetPack release: 7.2
• Dependencies: Requires openembedded-core (master branch).
• LAYERSERIES_COMPAT: blacksail

The USB gadget provides a serial TTY interface for communication between the Jetson and the host.

• On the Jetson device: The serial port is located at /dev/ttyGS0. A udev rule automatically starts serial-getty on this port when the device is created.
• On the Host (Linux): The corresponding serial device will appear as /dev/ttyACM0 (or /dev/ttyACMx if multiple ACM devices are present).

You can apply overlays stored in the rootfs partition instead of SPI flash by using the OVERLAYS option in extlinux.conf. This allows you to link overlays to a specific rootfs slot for easier updates.

Note: Only overlays that modify the kernel DTB are supported, as the application occurs late in the boot sequence.

When configuring camera capture on Jetson, choose the source plugin based on your hardware and software requirements:

• nvarguscamerasrc: The standard CSI camera source for most Jetson platforms. It uses the LibArgus camera API.
• nvsiplcamerasrc: An alternative source for cameras attached via the SIPL framework (available from L4T R39.2.0 / JetPack 7.2 onwards). This requires the jetson-sipl-api package. Use this for complex camera module configurations that require an ISP tuning database.

The documentation build and deployment process is automated via GitHub Actions using the .github/workflows/mdbook-versioned.yml workflow.

1. Build: On push to a tracked branch, the workflow runs mdbook build inside a peaceiris/mdbook container.
2. Deploy: The resulting HTML is pushed to a subdirectory in the main branch of the external OE4T/oe4t.github.io repository using peaceiris/actions-gh-pages.

Each branch is deployed to its own directory (e.g., master/, scarthgap/).

Note on Deployment Credentials: The deployment step requires a repository secret named OE4T_GITHUB_DEPLOY_KEY. If this secret is missing (as is common in forks), the workflow will skip the deployment step with a warning but will not fail.

NVIDIA-supplied Docker containers do not bundle most hardware-specific libraries; they expect them to be provided by the host OS. If you intend to run containers that require specific JetPack components, you must include them in your Yocto image.

Commonly required components include:

• TensorRT
• cuDNN
• Other JetPack-specific libraries

Additionally, for containers using GStreamer, ensure you include the necessary Tegra-specific GStreamer plugins.

When l4t-usb-device-mode is active, the system uses systemd-networkd to automatically configure a network bridge.

• Bridge Device: An l4tbr0 bridge is created, combining the usb0 (ECM) and rndis0 (RNDIS) interfaces.
• Device IP Address: The Jetson device is assigned 192.168.55.1 on this bridge.
• Host IP Address: A DHCP server runs on the device to assign the address 192.168.55.100 to the host machine connected via USB.

If you are new to the platform or want to try meta-tegra quickly without configuring a custom set of layers, use tegra-demo-distro as a starting point. It provides instructions to build several demo images that showcase the capabilities of meta-tegra and its companion layers.

https://github.com/OE4T/tegra-demo-distro

To provide custom device tree overlays (.dtbo) built from source, create a recipe that provides virtual/dtbo and inherits tegra-devicetree. The tegra-devicetree class ensures built files are installed to /boot/devicetree/ in the sysroot, where they are picked up by the l4t-launcher-extlinux recipe.

Recipe requirements:

• Inherit tegra-devicetree.
• Set PROVIDES = "virtual/dtbo".
• Include .dtso files in SRC_URI.
• Set PREFERRED_PROVIDER_virtual/dtbo in your machine or distro configuration.

inherit tegra-devicetree

PROVIDES = "virtual/dtbo"
COMPATIBLE_MACHINE = "(tegra)"

S = "${UNPACKDIR}"

SRC_URI = "file://my-board-overlay.dtso"