This repository contains a Linux kernel driver for AXI UART Lite over PCIe XDMA. The driver provides a TTY interface for seamless serial communication between the host and FPGA-based designs.

• Supports AXI UART Lite via PCIe XDMA
• Provides a TTY interface (/dev/ttyUL0)
• Supports RX polling for receiving data
• Compatible with Minicom and other serial tools

Ensure you have the necessary kernel headers installed, then run:

make

Once built, load the kernel module using:

sudo insmod uartlite_xdma.ko

To check if the module is loaded:

lsmod | grep uartlite_xdma

After loading the module, check if the device is available:

dmesg | grep UARTlite
ls /dev/ttyUL*

If the device exists, the driver is properly loaded.

Minicom is a terminal program that allows communication with the UART device.

sudo apt-get install minicom

sudo minicom -D /dev/ttyUL0 

-D /dev/ttyUL0 specifies the device

Type messages in the terminal, and they will be sent over UART. Any received data will be displayed in the terminal.

Press CTRL + A, then X, and confirm to exit.

In addition to the kernel driver, UARTLite can be accessed directly through PCIe XDMA using a lightweight Python API without the need for a custom kernel module.

This is useful for:

• Prototyping

• Debugging

• Bypassing the kernel for user-space experiments

Features:

• Direct memory access to UARTLite registers over XDMA

• Supports byte-by-byte send and receive

• Supports asyncio for low CPU usage during data reception

• Works with /dev/xdma0_user device

Key Operations:

• Reset FIFO at startup

• Polling UARTLite status register for RX/TX readiness

• Sending data to TX FIFO

• Receiving data from RX FIFO

• Async methods for efficient non-blocking reads

Simple receive loop (synchronous):

if __name__ == "__main__":
    uart = XdmaUartLite(device_index=0)

    print("Waiting for UARTLite data...")
    while True:
        data = uart.recv_data(128)  # Read 128 bytes
        if data:
            print(data.decode(errors="ignore").strip())

Or async version for optimal CPU usage:

async def main():
    uart = XdmaUartLite()
    while True:
        data = await uart.recv_data_async(128)
        print(data.decode(errors="ignore"))

asyncio.run(main())

sudo rmmod uartlite_xdma

make clean

Konstantin

This README provides clear instructions for building, testing, and using the driver with Minicom. Let me know if you need any modifications! 🚀