scripts/proto2-term

#!/usr/bin/env python3

# Copyright 2021 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import serial.tools.list_ports
from litex.tools.litex_term import LiteXTerm

def find_ports():
    """Returns a list of serial port devices which look like proto2 FPGA UART.
    """
    return [port_info.device for port_info in serial.tools.list_ports.comports()
            # 0403:6011 is FTDI FT4232H
            if port_info.vid == 0x0403
            and port_info.pid == 0x6011
            # Interface number 2 is the C channel
            and port_info.location.endswith(':1.2')]


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('port', nargs='?')
    parser.add_argument('--speed', metavar='BAUD', default=460800,
                        help='Set serial port to BAUD rate')
    args = parser.parse_args()

    if args.port is None:
        candidate_ports = find_ports()
        if len(candidate_ports) == 1:
            port = candidate_ports[0]
        elif len(candidate_ports) == 0:
            parser.error('FT4232H not found, is proto2 connected?')
        elif len(candidate_ports) > 1:
            parser.error('Multiple FT4232H devices found, '
                         'specify the port argument to choose one')
    else:
        port = args.port

    term = LiteXTerm(serial_boot=False, kernel_image=None,
                     kernel_address=None, json_images=None,
                     safe=True)
    term.open(port, args.speed)
    # Set C channel pin 4 high, to enable the level shifter for the FPGA UART
    term.port.dtr = False
    term.console.configure()
    term.start()
    term.join(True)

if __name__ == "__main__":
    main()