litex/soc/tools/remote/comm_uart.py

   1 import serial
   2 import struct
   3
   4
   5 class CommUART:
   6     msg_type = {
   7         "write": 0x01,
   8         "read":  0x02
   9     }
  10     def __init__(self, port, baudrate=115200, debug=False):
  11         self.port = port
  12         self.baudrate = str(baudrate)
  13         self.debug = debug
  14         self.port = serial.serial_for_url(port, baudrate)
  15
  16     def open(self):
  17         if hasattr(self, "port"):
  18             return
  19         self.port.open()
  20
  21     def close(self):
  22         if not hasattr(self, "port"):
  23             return
  24         del self.port
  25
  26     def _read(self, length):
  27         r = bytes()
  28         while len(r) < length:
  29             r += self.port.read(length - len(r))
  30         return r
  31
  32     def _write(self, data):
  33         remaining = len(data)
  34         pos = 0
  35         while remaining:
  36             written = self.port.write(data[pos:])
  37             remaining -= written
  38             pos += written
  39
  40     def read(self, addr, length=None):
  41         data = []
  42         length_int = 1 if length is None else length
  43         self._write([self.msg_type["read"], length_int])
  44         self._write(list((addr//4).to_bytes(4, byteorder="big")))
  45         for i in range(length_int):
  46             value = int.from_bytes(self._read(4), "big")
  47             if self.debug:
  48                 print("read {:08x} @ {:08x}".format(value, addr + 4*i))
  49             if length is None:
  50                 return value
  51             data.append(value)
  52         return data
  53
  54     def write(self, addr, data):
  55         data = data if isinstance(data, list) else [data]
  56         length = len(data)
  57         self._write([self.msg_type["write"], length])
  58         self._write(list((addr//4).to_bytes(4, byteorder="big")))
  59         for i, value in enumerate(data):
  60             self._write(list(value.to_bytes(4, byteorder="big")))
  61             if self.debug:
  62                 print("write {:08x} @ {:08x}".format(value, addr + 4*i))