Table of Contents
Introduction
Generally Yocto BSP support targets ASSP devices where the hardware itself is fixed. Devices such as Zynq and Zynq Ultrascale+, which also include a programmable fabric, require additional support to describe the custom IP that the developer has designed for the fabric. The meta-xilinx-tools
layer provides the recipes to parse a hardware platform specification file which will generate DTS, extract bitstreams, build low level boot objects and package the boot objects with bootgen.
Releases Supported
Xilinx Yocto rel-v2018.1
and later (Rocko 2.4)
Prerequisites
Creating a Custom Xilinx Yocto Layer
Adding a Hardware Platform to Your Yocto Layer
Local.conf
Add your hardware platform directly to your local.conf.
HDF_BASE = "file://" HDF_PATH = "/path-to/design_1_wrapper.xsa"
You may want to use machine overrides in your local.conf if you have multiple hardware archive files targeting different machines.
Machine Configuration Method
One way to manage your hardware platforms is to add them to a machine configuration. This method binds the hardware with a machine in the machine configuration. The example below uses a local hardware repository external to Yocto.
require conf/machine/zcu102-zynqmp.conf HDF_BASE = "file://" HDF_PATH = "/path-to/design_1_wrapper.xsa"
Bbappend Method
Another way to manage your HDFs is to add them to a bbappend
for the external-hdf
recipe. In order to manage multiple hardware designs and multiple machines, you can add the machine override to the HDF_BASE
and HDF_PATH
variables. This way you can use your layer as the repository for your hardware designs. In the example below, you can export all your hardware designs to the files
directory in the external-hdf
bbappend of your layer.
Version 2021 and earlier
FILESEXTRAPATHS_prepend := "${THISDIR}/files:" HDF_BASE_example-zcu102-zynqmp = "file://" HDF_PATH_example-zcu102-zynqmp = "design_1_wrapper.xsa"
Version 2022 and later
FILESEXTRAPATHS_prepend := "${THISDIR}/files:" HDF_BASE:example-zcu102-zynqmp = "file://" HDF_PATH:example-zcu102-zynqmp = "design_1_wrapper.xsa"
Using a default Hardware Platform with a Custom Machine
If you are a software developer, you may not care about the actual bitstream to get started working with software on an evaluation platform such as the ZCU102. However, you still need a base hardware platform to import the PCW configuration for the PS. Xilinx has default platforms for each platform on GitHub, but those only match the default machine name. If you are working with a custom machine configuration, you need to either use a local hardware platform or trick Yocto into using a compatible platform. For instance you could chose a naming convention that incorporates the default machine you are targeting, e.g. example-zcu102-zynmp.conf
. From this name you can extract the default platform. The bbappend
below shows how you could extend the external-hdf
recipe to use one of the default platforms with your custom machine. Essentially you are creating a link from your machine to the default machine in the working directory.
# attempt to determine a base machine assuming "<project>-<board>-<arch>" # example: "myproj-zcu102-zynqmp" could use "zcu102-zynqmp" platform from GitHub MACHINE_BASE = "${@'-'.join(MACHINE.rsplit('-')[-2:])}" do_deploy_prepend() { if [ "${MACHINE_BASE}" != "${MACHINE}" ] && [ -d ${WORKDIR}/git/${MACHINE_BASE} ]; then ln -sf ${MACHINE_BASE} ${WORKDIR}/git/${MACHINE} fi }
Legacy Formats
HDF_EXT = "xdf" HDF_EXT = "dsa"
Related Links
Creating a Custom Xilinx Yocto Layer