GenAVB/TSN

GenAVB/TSN is a generic AVB/TSN stack developed by NXP for NXP MCUs and MPUs. It is cross-platform, currently supporting Linux, FreeRTOS and Zephyr.

Supported hardware targets and configurations

This project supports several hardware targets and several different configuration modes. The table below summarizes the supported combinations, and their status for this specific release:

• O: supported by the project and validated for this release
• x: supported by the project, but not validated for this release
• empty cell: unsupported combination

Features

• IEEE-802.1AS-2020 implementation, both time-aware Bridge and Endpoint support.
• IEEE-802.1Q-2022 implementation, both Bridge and Endpoint Support
  • VLAN/FDB
  • Stream Reservation Protocol (Qat-2010)
  • Scheduled Traffic (Qbv-2015)
  • Frame preemption (Qbu-2016)
  • Per Stream Filtering and Policing (Qci-2017)
  • Forwarding and Queuing for Time-Sensitive Streams (Qav-2009)
• IEEE 802.1CB-2017 implementation for Frame Replication and Elimination for Reliability.
• IEEE 802.3br-2016 implementation for Interspersing Express Traffic.
• IEEE-1722-2016 implementation, with MAAP support.
• IEEE-1722.1-2013 implementation, with support for Milan v1.2 mode.
• IEC 62439-3:2022
  • High-availability Seamless Redundancy (HSR)
• Protocol stacks running in standalone userspace processes for Linux, and dedicated threads for FreeRTOS.
• Public C API provided by library plus header files.
• Example applications.

Repository structure

• api: the public API
• apps: source code and makefiles for example applications
• avdecc: IEEE 1722.1-2013/Milan v1.2 component stack
• avtp: IEEE 1722-2016 component stack
• common: common code
• configs: configuration files
• doc: documentation
• rtos: RTOS specific code
• gptp: IEEE 802.1AS-2020 component stack
• hsr: IEC 62439-3:2022 HSR component stack
• linux: Linux specific code
• maap: MAAP component code
• public: common code shared between applications and stack
• srp: IEEE 802.1Qat-2010 component stack

Build

GenAVB/TSN is using Cmake to generate build system.

Some preliminary configuration is required to provide path to the toolchain, staging directory and external components.

Local configuration files can be included by the build system in order to to define some variables specific to the developer environment. The local config file name is ./local_config_${target}.cmake

Build requirements

• Linux host system and development tools (git, make, doxygen for the docs, ...)
• An ARM gcc toolchain is sufficient for the stack. However building the linux applications requires a more complete cross-compilation SDK (because of additional dependencies such as alsa and gstreamer).
• AVB endpoint builds depend on custom changes to the Linux kernel and specific Yocto distribution: https://www.nxp.com/design/software/development-software/real-time-edge-software:REALTIME-EDGE-SOFTWARE
• FreeRTOS builds require additional MCUXpresso SDK software: https://www.nxp.com/design/software/development-software/mcuxpresso-software-and-tools-/wired-communications-middleware-for-nxp-microcontrollers:WIRED-COMM-MIDDLEWARE?fpsp=1&#avb-tsn
• Zephyr builds require the usage of an RTOS abstraction layer and additional NXP software. Refer to Harpoon Software for reference.

FreeRTOS

Currently GenAVB/TSN stack support only ARM gcc toolchain for FreeRTOS targets. To be able to build the stack, ARMGCC_DIR environment variable pointing to arm-gcc toolchain must be defined.

export ARMGCC_DIR=/path/to/gcc-arm-none-eabi-xxx

The local config file should define:

set(MCUX_SDK "/path/to/freertos_MCUXpresso_SDK" CACHE PATH "Path to MCUXpresso SDK")
set(RTOS_APPS "/path/to/freertos_application" CACHE PATH "Path to FreeRTOS application repository")

Zephyr

The GenAVB/TSN stack can be built as a Cmake subdirectory of a top level Zephyr application Refer to Harpoon Software for an example application.

Linux

The Linux target is usually built using a complete toolchain, which helps setting most of the environment variables required for cross-compilation. In the case of a Yocto SDK/toolchain for example, the following command will setup $CROSS_COMPILE as well as other related environment variables:

source /path/to/yocto/toolchain/environment-setup-xxx

The local config should however define:

set(KERNELDIR "/path/to/linux_avb" CACHE PATH "Path to Linux kernel")

Build commands

Syntax is:

cmake . -B<build directory> -DTARGET=<target name> -DCONFIG=<config name>
make -C <build directory> install

The GenAVB/TSN stack also provides a couple shell functions with auto-completion to facilitate the build process. Usage is

# Setup environment, see Build paragraph above
source environment-genavb
make_genavb [target] [config_list]
clean_genavb [target]

where target and config_list are optional. If no config_list is defined, all available configurations for specified target are built. If no target is specified the default is linux_imx6. config_list is of the form: configA configB ..., with one or more members.

To generate doxygen HTML documentation:

cmake . -B<build directory> -DBUILD_DOC=ON -DTARGET=<target name> -DCONFIG=<config name>
make -C <build directory> doc_doxygen

The generated documentation is available under <build_directory>/doc To install documentation under a custom path: use cmake variable -DDOC_OUTPUT_DIR=<custom absolute path>

Generated binaries

The generated binaries are installed under <build directory>/

Installing binaries to target

Linux

Copy the content of <build directory>/target/ to the root directory of the target filesystem

FreeRTOS

Refer to the FreeRTOS application README.

Zephyr

Refer to the Harpoon application README.