#!/usr/bin/python
import os
import serial
import sys

def calc_checksum(packet, length):
	crc =[0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78]

	v = 0x1012
	for i in range(4, length):
		vv = v >> 8
		v = vv ^ crc[((packet[i] ^ v) & 0xFF)]		
	return v



def dump_packet(dirn, packet):
	s = ' '.join(format(x, '02X') for x in packet)
	print "%s %s" % (dirn, s)

def build_packet(cmd, length, sequence_number):
	packet = bytearray(length+2)

	packet[0] = 0x55
	packet[1] = 0xAA
	packet[2] = 0x55
	packet[3] = 0xAA

	packet[4] = (length & 0xFF)
	packet[5] = (length >> 8)

	packet[7] = (sequence_number & 0xFF)
	packet[8] = (sequence_number >> 8)
	
	packet[9] = (cmd & 0xFF)
	packet[10] = (cmd >> 8)

	return packet

def do_receive(length, fail_txt):
	if read_response(ser,length) == False:
		print fail_txt
		exit()


def do_poll(ser, sequence_number):
	poll_packet = build_packet(0x0101, 0x20, sequence_number)

	crc = calc_checksum(poll_packet, 32)
	poll_packet.append(crc & 0xFF)
	poll_packet.append(crc >> 8)

#	dump_packet(">> ", poll_packet)
	ser.write(poll_packet)
	do_receive(35, "Poll Failed")

def do_update_init(ser, sequence_number):
	update_init_packet = build_packet(0x0233, 0x22, sequence_number)

	crc = calc_checksum(update_init_packet, 0x22)
	update_init_packet.append(crc & 0xFF)
	update_init_packet.append(crc >> 8)

#	dump_packet(">> ", update_init_packet)
	ser.write(update_init_packet)
	do_receive(35, "update_init Failed")

def do_fw(ser, fwd, sequence_number):
	fw_packet = build_packet(0x0235, 0x11F, sequence_number)
	fw_packet[30] = 0x01

	idx = 31
	for d in fwd:
		fw_packet[idx] = d
		idx = idx + 1
		
	crc = calc_checksum(fw_packet, 0x11F)
	fw_packet.append(crc & 0xFF)
	fw_packet.append(crc >> 8)

#	dump_packet(">> ", fw_packet)
	ser.write(fw_packet)
	do_receive(35, "update Failed")


def read_response(ser, len):
	bytes_read = ser.read(len)
	if bytes_read != '':
#		dump_packet("<< ", bytearray(bytes_read) )
		return True
	return False



if len(sys.argv) !=3:
	print "Usage: write <serialport> <filename>"
	exit() 


block_sz = 256
sequence_number = 0

ser = serial.Serial(sys.argv[1], 115200, timeout=1)
filename = sys.argv[2]

print "Uploading %s via %s" % (filename, ser.portstr)

filesz = os.path.getsize(filename)
dfile = open(filename, "r")

do_poll(ser, sequence_number)

do_update_init(ser, sequence_number)

for i in xrange(0, filesz, block_sz):
	fwd = dfile.read(block_sz)
	do_fw(ser, fwd, sequence_number)
	sequence_number = sequence_number + 1

print "Done"

ser.close()



