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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 (Rocko 2.4) rel-v2018.1 and later (Rocko 2.4)

Prerequisites

Creating a Custom Xilinx Yocto Layer

Adding a Hardware Platform to Your Yocto Layer

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Add your hardware platform directly to your local.conf.

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example-zcu102-zynqmp.conf

HDF_BASE = "file://"
HDF_PATH = "/path-to/design_1_wrapper.xsa"

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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. 

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example-zcu102-zynqmp.conf

require conf/machine/zcu102-zynqmp.conf

HDF_BASE = "file://"
HDF_PATH = "/path-to/design_1_wrapper.xsa"

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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

external-hdf.bbappend

FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

HDF_BASE_example-zcu102-zynqmp = "file://"
HDF_PATH_example-zcu102-zynqmp = "design_1_wrapper.xsa"

Version 2022 and later

external-hdf.bbappend

FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

HDF_BASE:example-zcu102-zynqmp = "file://"
HDF_PATH:example-zcu102-zynqmp = "design_1_wrapper.xsa"

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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.

external-hdf.bbappend

# 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

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example-zcu102-zynqmp.conf | local.conf

HDF_EXT = "xdf"
HDF_EXT = "dsa"

Related Links

Creating a Custom Xilinx Yocto Layer61702534

Adding a Hardware Platform to a Xilinx Yocto Layer

Xilinx Yocto Builds without an Internet Connection