#!/usr/bin/env python2
"""
Aufruf:
./dtprog.py <dthexfile> [-d /dev/ttyXXX] [-b <baudrate>]

bootROM, a very small bootloader for $NAME

protocol details:
abbrv: H = Host, CPU = C

value/cmd              | direction | comment
------------------------------------------------------------
'H'                    | H -> C    | enter bootROM ("HI")
'O'                    | C -> H    | ack bootROM entry ("OH HAI")

'W'0xZZZZZZZZ0xYYYYYYYY| H -> C    | write instr (0xYY...Y) to
                                   | address (0xZZ...Z)
'D'                    | C -> H    | instr write done

'R'0xZZZZZZZZ          | H -> C    | read instr from address (0xZZ..Z)
'F'0xYYYYYYYY          | C -> H    | instr read done and return instr

'Q'0xZZZZZZZZ0xYYYYYYYY| H -> C    | write data (0xYY...Y) to
                                   | address (0xZZ...Z)
'A'                    | C -> H    | data write done

'T'0xZZZZZZZZ          | H -> C    | read data from address (0xZZ..Z)
'G'0xYYYYYYYY          | C -> H    | read done and return data

'J'0xZZZZZZZZ          | H -> C    | jump to address (0xZZ...Z)
"""
import sys, time
from SerialPort_linux import SerialPort, SerialPortException

SPLIT = 30

class RAMSequence(object):
	def __init__(self, type, address, data):
		self.type = type
		self.addr = address
		self.data = data

def sendbyte(byte):
	"""
	send a byte to the TTY-device
	"""
	tty.write(chr(byte))

def sendword(word):
	"""
	send a word to the TTY-device
	"""
	sendbyte(word & 0xFF)
	sendbyte((word >> 8) & 0xFF)

def senddword(dword):
	"""
	send a dword to the TTY-device
	"""
	sendbyte((dword >> 24) & 0xFF)
	sendbyte((dword >> 16) & 0xFF)
	sendbyte((dword >> 8) & 0xFF)
	sendbyte(dword & 0xFF)

def recvbyte():
	"""
	receive a byte from the TTY-device
	"""
	return ord(tty.read())

def recvword():
	return (recvbyte() << 24) & (recvbyte() << 16) & (recvbyte() << 8) & recvbyte()

def bootromexec():
	sendbyte(0x4a) # 'J'

def brwriteinstr(address, data):
	"""
	send a WRITE-command (instr) to the bootROM-firmware
	"""
	# send WRITE instr command
	sendbyte(0x57) # 'W'
	# time.sleep(0.01)
	if (recvbyte() != 0x57): # 'W'
		print "host: write instr fail (1)"
		raise Exception
	senddword(address)
	senddword(data)
	time.sleep(0.01)
	if (recvbyte() != 0x44): # 'D'
		print "host: write instr fail (2)"
		raise Exception

def brwritedata(address, data):
	"""
	send a WRITE-command (data) to the bootROM-firmware
	"""
	# send WRITE instr command
	sendbyte(0x51) # 'Q'
	# time.sleep(0.01)
	if (recvbyte() != 0x51): # 'Q'
		print "host: write data fail (1)"
		raise Exception
	senddword(address)
	senddword(data)
	time.sleep(0.01)
	if (recvbyte() != 0x41): # 'A'
		print "host: write data fail (2)"
		raise Exception

def readdthexfile(filename): # desired dthex filename
	"""
	proceeds a dthex file
	"""
	filep = open(filename, "r")
	retval = [] # returns a list of FlashSequence objects
	linecount = 0
	for line in filep:
		linecount += 1
		# get rid of newline characters
		line = line.strip()

		# we're only interested in 0 or 1
		if line[0:1] == "0" or line[0:1] == "1":
			# TODO: checks...
			type = int(line[0:1], 10)
			addr = int(line[2:10], 16)/4
			data = int(line[11:19], 16)
			# print "type: ", type, "; addr: ", hex(addr), "; data: ", hex(data)
			retval.append(RAMSequence(type, addr, data))
	filep.close()
	return retval

def usage(execf):
	"""
	print usage of dtprog
	"""
	print "Usage: " + execf + " <target dthex-file> [-d DEVICE] [-b BAUDRATE]"
	print "maybe arg-eval fail. fix the source!"

def main(argv=None):
	"""
	main function of frprog
	"""
	# check command line arguments
	if argv is None:
		argv = sys.argv

	if len(argv) == 2 and (argv[1] == "-v" or argv[1] == "--version"):
		print "Version: lulz"
		return 0

	if len(argv) != 2 and len(argv) != 4 and len(argv) != 6:
		usage(argv[0])
		return 1

	# standard baudrate
	baudrate = 9200
	# standard serial device to communicate with
	device = "/dev/ttyS0"

	print "argv: ", argv
	# overrule standard device if provided with -d
	if len(argv) >= 4:
		if argv[2] == "-d":
			device = argv[3]
		else:
			usage(argv[0])
			return 1

	# overrule standard baudrate if provided with -b
	if len(argv) == 6:
		if argv[4] == "-b":
			baudrate = int(argv[5],10)
		else:
			usage(argv[0])
			return 1

	# read in data from mhx-files before starting
	try:
		ramseqs = readdthexfile(argv[1])
	except IOError, error:
		print argv[0] + ": Error - couldn't open file " + error.filename + "!"
		return 1

	print "Initializing serial port... (", device, ")"
	global tty
	tty = SerialPort(device, 100, baudrate)

	while True:
		tty.write('H')
		tty.flush()
		try:
			if tty.read() == 'O':
				break
		except SerialPortException:
			# timeout happened, who cares ;-)
			print "host: cpu in BootROM?"
			pass
	print "bootrom: OH HAI!"

	# save time at this point for evaluating the duration at the end
	starttime = time.time()
	time.sleep(0.1)

	sdots = SPLIT
	print "host: Transfering program to BootROM",
	print #TODO: remove ;)
	# let the fun begin!
	for seq in ramseqs:
		print "RAMing(", seq.type, ") ", hex(seq.data), " at address ",
		if seq.type == 1:
			# instruction
			print "", hex(seq.addr)
			print "host: writing instr"
			brwriteinstr(seq.addr, seq.data)
		elif seq.type == 0:
			# data
			print "", hex(seq.addr*4)
			print "host: writing data"
			brwritedata(seq.addr * 4, seq.data)
		tty.flush()

		sdots = sdots - 1
		if sdots == 0:
			sys.stdout.write(".")
			sys.stdout.flush()
			sdots = SPLIT
	print

	bootromexec()
	print "Program was started. Have fun!"
	duration = time.time() - starttime
	print "Procedure complete, took", round(duration, 2), "seconds."

if __name__ == '__main__':
	sys.exit(main())