FreeBSD on Zynq-7000 / Zybo / Zedboard / Ultra96
This page describes running
FreeBSD
on the
Zedboard and other
Xilinx Zynq-7000 platforms.
The Zynq-7000 is an interesting platform combing a Xilinx 7-series FPGA
fabric with a dual-core ARM Cortex-A9 based Application Processor Unit
(System-on-a-Chip).
The Zedboard is an evaluation board for
the Zynq-7000. It is manufactured by
Digilent.
More information on the Zedboard can be found at
www.zedboard.org.
The information on this page is migrating to the FreeBSD wiki at
http://wiki.freebsd.org/FreeBSD/arm/Zedboard.
Ultra96:
A Display Port driver works on the Ultra96 board. It only supports 1920 x 1080 @ 60 hz.
FreeBSD can boot on the Zynq UltraScale+ based
Ultra96
board from
Avnet.
An arm64 GENERIC kernel boots on the Ultra96 but has limited functionality
due to lack of drivers. Starting with a FreeBSD aarch64 snapshot, all that
is needed is to add a fairly generic BOOT.BIN file and a custom device tree
blob.
Building a bootable FreeBSD SD image for Ultra96:
Here is a recipe for creating a bootable SD card image from a
Raspberry Pi 3 snapshot:
- Retrieve an RPI3 snapshot from FreeBSD. For example, I started with
FreeBSD-13.0-CURRENT-arm64-aarch64-RPI3-20200102-r356261.img.xz.
- Decompress the image:
xz -d FreeBSD-13.0-CURRENT-arm64-aarch64-RPI3-xxx.img.xz.
- Mount the MSDOS partion:
mdconfig -f FreeBSD-13.0-CURRENT-arm64-aarch64-RPI3-xxx.img
mkdir /mnt/boot # (if necessary)
mount -t msdosfs /dev/md0s1 /mnt/boot
- Optionally, clean out all the uneeded stuff (leaving only EFI/BOOT/bootaa64.efi):
rm -fr /mnt/boot/[A-DF-Za-z]*
- Copy BOOT.BIN to boot partition:
(See notes below on how I created BOOT.BIN using Xilinx tools.)
cp BOOT.BIN /mnt/boot
- Copy device tree blob,
ultra96-rev1.dtb, to boot partition:
mkdir -p /mnt/boot/dtb/xilinx
cp ultra96-rev1.dtb /mnt/boot/dtb/xilinx
- Unmount:
umount /mnt/boot
mdconfig -d -u 0
- Write image to an SD card:
dd if=FreeBSD-13.0-CURRENT-arm64-aarch64-RPI3-xxx.img of=/dev/da0 bs=1m
- Install SD card in Ultra96 and boot (make sure boot switches are set
to boot from SD).
DTS files for FreeBSD on Ultra96
Although I have a modified FreeBSD kernel running on the Ultra96 using the
upstream DTS files, the drivers in the GENERIC kernel do not yet handle
all the driver FDT compatible strings and properties. My custom DTS files
for using the GENERIC kernel are on github
here.
To create the dtb, use dtc, the device tree compiler:
dtc -I dts -O dtb avnet-ultra96-rev1.dts > ultra96-rev1.dtb
About BOOT.BIN:
BOOT.BIN is a binary that the Zynq UltraScale+ uses to boot. The following
is the .bif file used to create BOOT.BIN using bootgen, a tool included in
the Xilinx Vivado software suite:
image :
{
[bootloader, destination_cpu=a53-0] fsbl.elf
[destination_device=pl] design_1_wrapper.bit // optional
[pmufw_image] pmufw.elf
[destination_cpu=a53-0, exception_level=el-3, trustzone] bl31.elf
[destination_cpu=a53-0, exception_level=el-2] u-boot.elf
}
This is the bootgen command to create BOOT.BIN:
bootgen -arch zynqmp -image boot.bif -o BOOT.BIN
The following are vague descriptions of how I built each of the software
componentsin BOOT.BIN. I have put these individual binaries in
this directory.
- fsbl.elf
This is the "First Stage Boot Loader." It initializes most of the Zynq
hardware including DRAM controller settings, clocks, power domains, etc.
I created a minimal design in Vivado and used Vitis to build a Platform
Project. The platform project builds the FSBL. The stdin and stdout
settings are changed from the default psu_uart_0 to psu_uart_1 in the
Board Support Package Settings.
- design_1_wrapper.bit
This is the PL (FPGA) bitstream file generated by Vivado. This is optional.
- pmufw.elf
This is the "Platform Management Firmware" that runs on a Microblaze CPU
dedicated to power, reset, and clock control. This software is also
generated by Xilinx Vitis when a Platform Project is created. The stdin
and stdout settings are changed from the default psu_uart_0 to psu_uart_1
in the Board Support Package Settings.
- bl31.elf
This is the secure monitor software that runs at EL3 on the ARM CPU and
handles all PSCI functions. The source is available from Xilinx'
Github page.
It is built with the following options:
gmake CROSS_COMPILE=aarch64-linux-gnu- PLAT=zynqmp RESET_TO_BL31=1 DEBUG=1 ZYNQMP_CONSOLE=cadence1
u-boot.elf
This u-boot ELF is built from
u-boot sources:
git clone https://gitlab.denx.de/u-boot/u-boot u-boot
cd u-boot
make CROSS_COMPILE=aarch64-linux-gnu- xilinx_zynqmp_virt_defconfig
make -j4 CROSS_COMPILE=aarch64-linux-gnu- DEVICE_TREE="avnet-ultra96-rev1"
Zedboard: Pre-built SD card image
An SD card image for the Zedboard based upon FreeBSD 12.1-RELEASE
is available here:
FreeBSD-12.1-ZEDBOARD-354239.img.xz.
SHA256 (FreeBSD-12.1-ZEDBOARD-354239.img) = 0c42d842c3e697b175aa13bb9033e0c9f32bfa78916e0756c4eb501a468c6c77
SHA256 (FreeBSD-12.1-ZEDBOARD-354239.img.xz) = b49f69c3eaa389a5e17d916efede0297ebb22ed8808e509e2c4b7c83a415cf03
If you would like to test-drive FreeBSD on a Zedboard, download the
xz compressed SD card image.
Uncompress and copy the image to the SD card.
On my machine, the SD card shows up as /dev/da0.
Be sure that is the same on your machine before cut and
pasting this.
xz --decompress FreeBSD-12.1-ZEDBOARD-354239.img.xz
dd if=FreeBSD-12.1-ZEDBOARD-354239.img of=/dev/da0 bs=1m
Boot It
Power down the Zedboard.
Insert the SD card in the SD slot and be sure the Zedboard's
configuration mode jumpers are set for booting from the SD card before
powering up. (If you've already been booting the Linux image from the SD card
shipped with the Zedboard, you shouldn't need to change anything.)
The USB-UART connected to connector J14 acts as the FreeBSD console (device
uart1). This is the same console as the stock Linux image.
The Zedboard should automatically boot U-boot and then the FreeBSD
kernel.
The FreeBSD kernel has drivers for the UARTs, SDHCI, Gig Ethernet, and
a USB host driver for the USB OTG connected at J13. There is also a GPIO
driver which allows reading of switches and buttons and controlling the
LEDs.
Note: Booting this pre-built image will not display "FreeBSD" on
the OLED display as shown in the picture. It was a separate C program I
wrote a while ago and now I can't find it!
Please send any feedback to me via
E-mail
Zybo:
FreeBSD also runs on the
Zybo.
The Zybo from Digilent Inc. is a lower cost board than the Zedboard.
Here is a pre-built SD card image for Zybo based upon FreeBSD 12.1-RELEASE:
FreeBSD-12.1-ZYBO-354239.img.xz.
SHA256 (FreeBSD-12.1-ZYBO-354239.img) = 5d3c1eed42dd4b8ff19b576bb1726953020f82a2aae5f1fd2fbcef54244abe27
SHA256 (FreeBSD-12.1-ZYBO-354239.img.xz) = 4c9aedd1b79a843ec5af52f50f964d4e7be8bac36b8133e234ab441ba848fd06
Follow the instructions above in the Zedboard section to uncompress and copy
the image to an SD card. To boot the image on Zybo, don't forget to set
the mode jumper (JP5) to boot from SD.
Note: This image is for the original Zybo which has been retired and
replaced by the
Zybo Z7
board. This image will not work on the Zybo Z7.
Building an SD Image
Build world and kernel
First, we need to build world for armv7 and a kernel for Zedboard:
From the source directory /usr/src:
make TARGET_ARCH=armv7 KERNCONF=ZEDBOARD buildworld buildkernel
Create an SD card image
The following creates SD card image with an msdos boot partition.
dd if=/dev/zero of=SDCARD.img bs=1m count=2500
mdconfig -f SDCARD.img -u 0
gpart create -s MBR md0
gpart add -s64m -t \!14 md0
gpart set -a active -i 1 md0
newfs_msdos -F 16 /dev/md0s1
gpart add -t freebsd md0
gpart create -s BSD md0s2
gpart add -t freebsd-ufs md0s2
newfs /dev/md0s2a
Mount SD card partitions
mkdir /mnt/boot /mnt/armroot
mount -t msdosfs /dev/md0s1 /mnt/boot
mount /dev/md0s2a /mnt/armroot
Copy boot files
The Zynq chip needs several files in an msdos boot partition to boot FreeBSD:
boot.bin
u-boot.img
EFI/BOOT/bootarm.efi
dtb/zynq-zynq.dtb
The boot.bin and u-boot.img come from the u-boot-zedboard port in
/usr/ports/sysutils/u-boot-zedboard.
cp /usr/local/share/u-boot/u-boot-zedboard/{boot.bin,u-boot.img} /mnt/boot
The efi boot loader is built by buildworld (see above). The binary is found
in /usr/obj/usr/src/arm.armv7/stand/efi/loader_lua/loader_lua.efi. Copy it over:
mkdir -p /mnt/boot/EFI/BOOT
cp /usr/obj/usr/src/arm.armv7/stand/efi/loader_lua/loader_lua.efi /mnt/boot/EFI/BOOT/bootarm.efi
Last, we need the dtb file. U-boot defaults to using "zynq-zynq.dtb" as the dtb:
mkdir /mnt/boot/dtb
dtc -I dts -O dtb /usr/src/sys/dts/arm/zedboard.dts > /mnt/boot/dtb/zynq-zynq.dtb
Populate root and boot partitions
From within the source directory:
make TARGET_ARCH=armv7 KERNCONF=ZEDBOARD DESTDIR=/mnt/armroot installworld distribution installkernel
Final tweaks
Copy a couple more files:
cp fstab rc.conf /mnt/armroot/etc
Create a mount point for the boot partition:
mkdir /mnt/armroot/boot/msdos
Touch /firstboot:
touch /mnt/armroot/firstboot
Unmount file systems
umount /mnt/boot
umount /mnt/armroot
mdconfig -d -u 0
Copy to an SD card
dd if=SDCARD.img of=/dev/da0 bs=1m
Updated: June 2020
Thomas Skibo
E-mail Me