Petalinux platform project for Avnet Ultra96

This repository contains a Petalinux project (hardware and software) for the Avnet Ultra96 board. It consists of a Vivado hardware definition, Linux kernel, PetaLinux-based OS and assorted bootloaders, and will hopefully be a stable platform option for SDR (Software Defined Radio) experimentation.

Right now, the changes from the original Xilinx Ultra96 BSP image are (newest changes on top):

• Disabled fan speed control for the time being, as this version of the design turned out to be very unstable, particularly with active JTAG. Random crashes (particularly at U-Boot prompt) before Linux is up. Once the Linux kernel has started, I see random hardware problems popping up after a few hours, mostly related to interrupts not reacting. mmc, bluetooth and others. My attempts at troubleshooting this were not successful.

  Worked around this for now by removing the System Management Wizard and hardwiring the temperature input of the fan control to super hot. At some point I need to take another look at this. Preferably after reading the sections on the DRP and the Sysmon interface in UG580, as well as Sysmon sequence modes in UG1085.

• Added Fan speed control! This makes the Ultra96 a much better workbench buddy. The implementation is all in hardware, so it doesn't rely on a particular driver. It keeps the chip temperature of the SDSoC in the low 50 C range (this is configurable, please see the linked article). Warning: If this doesn't work quite right, damage to the hardware is possible. I have played with this enough to trust it, but you may want to double-check. The sensors command is avaialble on the shell when logged into the Ultra96, which will tell you the temperature (and a lot of other stuff).

• Tested the video output - I found a mini-DP to VGA adapter that works with the Ultra96, and I as able to verify that it does indeed work. If you connect a monitor to the mini-DP port and a keyboard to the USB3, you can log in from there.

• Removed a bunch of demo software

• Added sshd, Python3, SWIG, Sqlite, VFIO

• Applied the fix from Xilinx Answer Record AR71722. Now the Ultra96 will shut down and turn itself off if you press the power button while it is running.

• Added drivers for some popular Realtek-based USB Ethernet dongles (so you can use Ethernet, or even TFTP-boot!)

• Rewired the console port to use the console connector (so this will work with the AES-ACC-U96-JTAG adapter board)

Coming soon

• Make this into a platform for SDSoC. A great article on this subject has been published by Anuj Vaishnav recently, which should make this quite achievable.
• Binaries, so anybody can try this out without 10s of GB of downloads, hours of computation and gobs of disk space.

Tool versions

This is built with the 2018.2 versions of Vivado as well as PetaLinux. There is a branch for migration to 2018.3, but I put this on hold for the time being. It appears that the support for SDSoC is a lot more mature with 2018.2. The only known deficiency for now is the inability of the included UBoot version to write its environment into a disk file. For the moment, I can live with this.

What's with the name?

PlusUltra is the negation of "Non plus ultra" (which means for "Nothing further beyond"). It is also the national motto of Spain.

Building a system

make sure you clone this repository using the --recursive git option, as this project contains a git submodule. Forgot to do that? No problem, just run git submodule update --recursive from a command line, which will take care of updating the submodule.

Building the hardware project

You need Xilinx Vivado 2018.2 for this part. Open the project hardware/xilinx-ultra96-reva-2018.2/xilinx-ultra96-reva-2018.2.xpr, and make any changes you desire. Build the bitstream. If it is successful, you want to export the hardware definition to the default location (make sure to check the checkbox to include the bitfile). Then you can proceed to build a matching software image.

Type the following into Vivado's tcl console:

write_dsa -force -include_bit ./hardware/PlusUltra/PlusUltra.sdk/PlusUltra.dsa

Building the software

You will need an installation of Petalinux 2018.2 from Xilinx (please note that this needs to be installed on a Linux machine). Refer to the Xilinx documentation on how to do this, specifically chapter 2 of UG1144, which lists the installation requirements. Please make sure you are not building this on an ecryptfs file system, as path length restrictions will probably trip you up!

• Don't forget to import the Petalinux system variables
• Change directories to the root of the project
• run petalinux-config --get-hw-description hardware/xilinx-ultra96-reva-2018.2/xilinx-ultra96-reva-2018.2.sdk. If you are presented with a configuration screen, you can exit out, the default options should work.
• run petalinux-build
• This is going to take a while.
• No, really, find something else to do.
• Change directory to images/linux
• run petalinux-package --boot --force --fsbl zynqmp_fsbl.elf --fpga system.bit --u-boot --pmufw pmufw.elf. This will create a file BOOT.BIN that contains boot loaders and the FPGA image.

Deploying to hardware

You will need an SD card that is partitioned and formatted into two partitions:

• A FAT32 partition of a few 100 MB
• An ext4 partition for the rest of the SD card

You will want to copy the build products image.ub and BOOT.bin to the FAT32 partition. The other partition is for the root file system, and Petalinux has helpfully packaged that up for you in a million different ways. The easiest way to get this onto the SD card (given that you are on a Linux machine anyway) is to use tar onto the SD partion. For example, if the ext4 partition is mounted on your PC as /media/foo, you want to run sudo tar xvf rootfs.tar.gz -C /media/foo. This needs to be run with sudo to get the right permissions onto the file system.

Booting and playing around.

Insert the SD card into your Ultra96 board and power it up. If you have a console connected to the console connector, you should see the boot progressing. Either way, you should be able to connect the board the same way that you connected to it with the out-of-the-box image.

Building a platform for SDSoC

Run 'tools\makeBootfolder` to create the 3 components required to build an SDSoC platform.

Contributing to this effort

Congratulations, you are now running your first home-baked hardware and software image! If you find anything wrong or broken, please submit an issue, or make it better by sending a pull-request with your improvments. Even if you have never done it before. Especially if you have never done it before! Don't worry about "doing it right", we can figure it out together. If you want to contribute but don't know what, documentation is always a good place to start.