import string
import time
import serial
from struct import *
import time
from migen.fhdl.structure import *

WRITE_CMD  = 0x01
READ_CMD   = 0x02
CLOSE_CMD  = 0x03

def write_b(uart, data):
	uart.write(pack('B',data))

class Uart2Csr:
	def __init__(self, port, baudrate, debug=False):
		self.port = port
		self.baudrate = baudrate
		self.debug = debug
		self.uart = serial.Serial(port, baudrate, timeout=0.25)
			
	def read(self, addr, burst_length=1):
		write_b(self.uart, READ_CMD)
		write_b(self.uart, burst_length)
		write_b(self.uart, (addr & 0xff000000) >> 24)
		write_b(self.uart, (addr & 0x00ff0000) >> 16)
		write_b(self.uart, (addr & 0x0000ff00) >> 8)
		write_b(self.uart, (addr & 0x000000ff))
		values = [] 
		for i in range(burst_length):
			read = self.uart.read(1)
			val = int(read[0])
			if self.debug:
				print("RD %02X @ %08X" %(val, addr + 4*i))
			values.append(val)
		if burst_length == 1:
			return values[0]
		else:
			return values

	def read_n(self, addr, n, endianess = "LE"):
		r = 0
		words = int(2**bits_for(n-1)/8)
		for i in range(words):
			if endianess == "BE":
				r += self.read(addr+i)<<(8*i)
			elif endianess == "LE":
				r += self.read(addr+words-1-i)<<(8*i)
		if self.debug:
			print("RD @ %04X" %addr)
		return r		
		
	def write(self, addr, data):
		if isinstance(data, list):
			burst_length = len(data)
		else:
			burst_length = 1
		write_b(self.uart, WRITE_CMD)
		write_b(self.uart, burst_length)
		self.uart.write([(addr & 0xff000000) >> 24,
						(addr & 0x00ff0000) >> 16,
						(addr & 0x0000ff00) >> 8,
						(addr & 0x000000ff)])
		if isinstance(data, list):
			for i in range(len(data)):
				write_b(self.uart, data[i])
				if self.debug:
					print("WR %02X @ %08X" %(elt, addr + 4*i))
		else:
			write_b(self.uart, data)
			if self.debug:
				print("WR %02X @ %08X" %(data, addr))

	def write_n(self, addr, data, n, endianess = "LE"):
		words = int(2**bits_for(n-1)/8)
		for i in range(words):
			if endianess == "BE":
				self.write(addr+i, (data>>(8*i)) & 0xFF)
			elif endianess == "LE":
				self.write(addr+words-1-i, (data>>(8*i)) & 0xFF)
		if self.debug:
			print("WR %08X @ %04X" %(data, addr))