PYNQ networking overlay enables networking capabilities from PL on the board. Traditionally, the PS on ZYNQ board connects to the Ethernet port, while this overlay also bridges the PL on ZYNQ to the Ethernet port. MQTT-SN is implemented on this overlay, leveraging the scapy python library.

On the latest PYNQ image, use the following command in a terminal.

sudo apt-get install tcpdump iptables ebtables bridge-utils
sudo pip3 install --upgrade git+https://github.com/Xilinx/PYNQ-Networking.git

After the setup, the notebook folder will be populated, and users can try the demo there. Users do not have to run any additional steps.

Note: For completeness, the following few sections introduce what have been done to the PYNQ image. These steps do not need to be performed by users, since they will be taken care of when this package is being installed.

This package requires the boot files to be compatible. For example, the device tree must have the following patch:

/ {
	chosen {
		bootargs = "console=ttyPS0,115200 root=/dev/mmcblk0p2 rw earlyprintk rootfstype=ext4 rootwait devtmpfs.mount=1 uio_pdrv_genirq.of_id=\"generic-uio\"";
		linux,stdout-path = "/amba@0/serial@E0001000";
	};

	amba {

		fabric@40000000 {
			compatible = "generic-uio";
			reg = <0x40000000 0x10000>;
			interrupt-parent = <&intc>;
			interrupts = <0x0 0x1d 0x4>;
		};

		ethernet@e000b000 {
			phy-handle = <&ethernet_phy>;
                        ethernet_phy: ethernet-phy@1{
				reg = <1>;
			};
		};

		slcr@f8000000 {
			clkc@100 {
				fclk-enable = <0xf>;
			};
		};
	};


	xlnk {
		compatible = "xlnx,xlnk-1.0";
		clock-names = "xclk0", "xclk1", "xclk2", "xclk3";
		clocks = <&clkc 0xf &clkc 0x10 &clkc 0x11 &clkc 0x12>;
	};
	usb_phy0: phy0 {
		compatible = "ulpi-phy";
		#phy-cells = <0>;
		reg = <0xe0002000 0x1000>;
		view-port = <0x170>;
		drv-vbus;
	};
   
};

&usb0 {
	usb-phy = <&usb_phy0>;
};

The ethernet entry must have bridging enabled as above.

Again, if you are on the latest PYNQ image, you do not have to do this step.

Users can modify the eth0 port on Linux (/etc/network/interfaces.d/eth0). An example of the modified file is stored in interfaces.d folder of this repository.

This step will be performed automatically during the installation process. A backup of the original file is also produced in the same directory (/etc/network/interfaces.d/).