Ultra96-NFS-Boot

This is an instruction to build the PYNQ v2.7 image for Ultra96-V2 board with root filesystem from NFS (Network File System).

Build Environment

• Ubuntu 20.04
• Vitis 2020.2
• PetaLinux 2020.2

Steps

Prepare NFS folder on host

A NFS server should be setup on the host with some folders being shared

1. Download the PYNQ v2.7 SD card image for Ultra96-V2 board from PYNQ official website

2. We need files in the second partition of the image file. First check out the start offset of the second partition.

   fdisk <path_to_img>/Ultra96v2-2.7.0.img

   Then enter p from keyboard.

   

   Here the offset is 268288.

3. Mount the second partition with offset = 268288*512 = 137363456

   mount -o loop,offset=137363456 <path_to_img>/Ultra96v2-2.7.0.img <mount_path>/

4. Copy all the files to NFS shared folder

   cp <mount_path>/* <NFS_shared_folder>

Build the boot files

1. Clone the PYNQ repository from github.

   git clone https://github.com/Xilinx/PYNQ.git --branch image_v2.7

   cd PYNQ

2. Copy the Ultra96v2 folder in this repository to boards folder.
3. Edit the file sdbuild/boot/meta-pynq/recipes-kernel/linux/linux-xlnx/pynq.cfg, modify line 12 to mark the RTL8152 driver as built-in.

   CONFIG_USB_RTL8152=y
   

4. Open and edit the file sdbuild/Makefile.
   • Delete line 145 and 146
     • echo 'CONFIG_SUBSYSTEM_ROOTFS_EXT4=y' >> $$(PL_CONFIG_$1)
     • echo 'CONFIG_SUBSYSTEM_SDROOT_DEV="/dev/mmcblk0p2"' >> $$(PL_CONFIG_$1)
   • Incert below three lines around line 146, replace the field "/NFS/rootfs" and "192.168.1.x" with the NFS path and the IP address of NFS server

     echo 'CONFIG_SUBSYSTEM_ROOTFS_NFS=y' >> $$(PL_CONFIG_$1)
     echo 'CONFIG_SUBSYSTEM_NFSROOT_DIR="/NFS/rootfs"' >> $$(PL_CONFIG_$1)
     echo 'CONFIG_SUBSYSTEM_NFSSERVER_IP="192.168.1.x"' >> $$(PL_CONFIG_$1)
     

5. Edit the file sdbuild/boot/meta-pynq/recipes-bsp/device-tree/files/pynq_bootargs.dtsi, change the bootargs in line 3:

   bootargs = "root=/dev/nfs nfsroot=192.168.1.x:/NFS/rootfs,nfsvers=3,tcp ip=dhcp rw rootwait earlyprintk devtmpfs.mount=1 uio_pdrv_genirq.of_id=\"generic-uio\" clk_ignore_unused";
   

   Replace the field "/NFS/rootfs" and "192.168.1.x" as above.
6. Setup environment

   source <Vitis_installation_path>/settings64.sh
   source <PetaLinux_installation_path>/settings.sh

   sudo sdbuild/scripts/setup_host.sh

7. Run make to start build

   cd sdbuild

   make boot_files BOARDS=Ultra96v2

8. When finished, the boot files (boot.scr, BOOT.BIN, image.ub) are saved in sdbuild/output/boot/Ultra96v2/
9. Replace the files in the fist partition of SD card with the newly built files.