#! /usr/bin/env python


"""
Download configuration over SPI to DIPSY (a sub-5 USD FPGA board).

Raspberry PI (excerpt from https://github.com/piface/pifacecommon/blob/master/docs/installation.rst):
1. Remove "spi-bcm2708" from the blacklist in /etc/modprobe.d/raspi-blacklist.conf
   or (kernel 3.18 or newer): add dtparam=spi=on to /boot/config/txt
2. Reboot or modprobe spi-bcm2708
3. Pinout on P1:
	25 = GND
	23 = SCLK
	22 = RESET
	21 = MISO
	20 = GND
	19 = MOSI
	18 = DONE
	17 = +3.3V
	16 = SS

Intel Edison Arduino breakout:
1. Update to the latest version as of 2015-09-05.
2. Pinout on J1B1:
	 8 = RESET
	 9 = DONE
	10 = SS
	11 = MOSI
	12 = MISO
	13 = SCK


Beaglebone (tested on revision A3):
1. Update to the latest Debian image.
2. Pinout on P9
	1,2 = GND
	3,4 = +3.3V
   Pinout on P8
	 8 = RESET
	10 = SS
	12 = DONE
	14 = MOSI
	16 = SCK
"""

def split_by_size(s,n):
	r = []
	while len(s)>n:
		r.append(s[0:n])
		s = s[n:]
	if len(s)>0:
		r.append(s)
	return r

_ZEROES = b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'

_STATUS_OK = 1
_STATUS_NOT_DONE = 2
_STATUS_NOT_PROGRAMMING = 3

import sys
import os
import time

_hw = None

try:
	import pifacecommon.spi as SPI
	import RPi.GPIO as GPIO
	_hw = "Raspberry PI"
	_SPI_DEVICE = "/dev/spidev0.0"
	# P1 header numbering.
	_CRESET_PIN     = 22
	_CDONE_PIN      = 18
	_SS_PIN         = 16
	def configure_dipsy(configObject):
		# SPIDevice(bus, chip_select, spi_callback)
		spi = SPI.SPIDevice(0, 0, None)
		# P1 header pin numbering.
		GPIO.setmode(GPIO.BOARD)
		try:
			GPIO.setup(_CRESET_PIN, GPIO.OUT)
			GPIO.setup(_CDONE_PIN, GPIO.IN)
			GPIO.setup(_SS_PIN, GPIO.OUT)

			GPIO.output(_CRESET_PIN, GPIO.LOW)
			GPIO.output(_SS_PIN, GPIO.LOW)
			time.sleep(0.01)
			GPIO.output(_CRESET_PIN, GPIO.HIGH)
			time.sleep(0.01)

			# up to 4096 possible, but no benefit.
			config_list = split_by_size(configObject, 1024)
			for c in config_list:
				spi.spisend(c)
			
			done = GPIO.input(_CDONE_PIN)
			spi.spisend(_ZEROES)
			GPIO.output(_SS_PIN, GPIO.HIGH)

			GPIO.setup(_CRESET_PIN, GPIO.IN)
			GPIO.setup(_SS_PIN, GPIO.IN)
		finally:
			GPIO.cleanup()
		if done:
			return _STATUS_OK
		else:
			return _STATUS_NOT_DONE
except ImportError:
	pass

if not _hw:
	try:
		import mraa
		_hw = "Intel Edison"
		_CRESET_PIN     = mraa.Gpio(8)
		_CDONE_PIN      = mraa.Gpio(9)
		_SS_PIN         = mraa.Gpio(10)
		# For some reason, HW SPI didn't work.
		_MOSI_PIN	= mraa.Gpio(11)
		_MISO_PIN	= mraa.Gpio(12)
		_SCK_PIN	= mraa.Gpio(13)
		def configure_dipsy(configObject):
			_CRESET_PIN.dir(mraa.DIR_OUT)
			_CDONE_PIN.dir(mraa.DIR_IN)
			_CDONE_PIN.mode(mraa.MODE_HIZ)
			_SS_PIN.dir(mraa.DIR_OUT)
			_MOSI_PIN.dir(mraa.DIR_OUT)
			_MISO_PIN.dir(mraa.DIR_IN)
			_MISO_PIN.mode(mraa.MODE_HIZ)
			_SCK_PIN.dir(mraa.DIR_OUT)

			try:
				_CRESET_PIN.write(0)
				_SS_PIN.write(0)
				_MOSI_PIN.write(0)
				_SCK_PIN.write(0)
				time.sleep(0.01)
				_CRESET_PIN.write(1)
				time.sleep(0.01)
				programming = _CDONE_PIN.read()

				all_bytes = configObject + _ZEROES
				for c in all_bytes:
					b = ord(c)
					for bit in range(0,8):
						_MOSI_PIN.write((b >> (7-bit)) & 1)
						_SCK_PIN.write(1)
						_SCK_PIN.write(0)
				time.sleep(0.01)
				done = _CDONE_PIN.read()
				_SS_PIN.write(1)
			finally:
				# Can't change direction, this will reset Dipsy.
				_CRESET_PIN.mode(mraa.MODE_PULLUP)
				_SS_PIN.mode(mraa.MODE_HIZ)
				_MOSI_PIN.mode(mraa.MODE_HIZ)
				_SCK_PIN.mode(mraa.MODE_HIZ)
			if done:
				return _STATUS_OK
			else:
				return _STATUS_NOT_DONE
	except ImportError:
		pass

if not _hw:
	try:
		import Adafruit_BBIO.GPIO as GPIO
		_hw = "Beaglebone"

		# P8
		_CRESET_PIN     = "P8_8"
		_SS_PIN         = "P8_10"
		_CDONE_PIN      = "P8_12"
		# HW SPI by default not enabled on Beaglebone.
		_MOSI_PIN	= "P8_14"
		_SCK_PIN	= "P8_16"

		def configure_dipsy(configObject):
			try:
				GPIO.setup(_CRESET_PIN, GPIO.OUT)
				GPIO.setup(_CDONE_PIN, GPIO.IN)
				GPIO.setup(_SS_PIN, GPIO.OUT)
				GPIO.setup(_MOSI_PIN, GPIO.OUT)
				GPIO.setup(_SCK_PIN, GPIO.OUT)

				GPIO.output(_CRESET_PIN, GPIO.LOW)
				GPIO.output(_SS_PIN, GPIO.LOW)
				GPIO.output(_MOSI_PIN, GPIO.LOW)
				GPIO.output(_SCK_PIN, GPIO.LOW)
				time.sleep(0.01)
				GPIO.output(_CRESET_PIN, GPIO.HIGH)
				time.sleep(0.01)

				all_bytes = configObject + _ZEROES
				for c in all_bytes:
					b = ord(c)
					for bit in range(0,8):
						if (b >> (7-bit)) & 1:
							GPIO.output(_MOSI_PIN, GPIO.HIGH)
						else:
							GPIO.output(_MOSI_PIN, GPIO.LOW)
						GPIO.output(_SCK_PIN, GPIO.HIGH)
						GPIO.output(_SCK_PIN, GPIO.LOW)
				
				time.sleep(0.01)
				done = GPIO.input(_CDONE_PIN)
				GPIO.output(_SS_PIN, GPIO.HIGH)

				GPIO.setup(_CRESET_PIN, GPIO.IN)
				GPIO.setup(_SS_PIN, GPIO.IN)
			finally:
				GPIO.cleanup()
			if done:
				return _STATUS_OK
			else:
				return _STATUS_NOT_DONE
	except ImportError:
		pass


if not _hw:
	print("Unknown hardware platform.")
	sys.exit(2)
else:
	print("Hardware platform: " + _hw)

if len(sys.argv)<2:
	print "No configuration file for DIPSY specified on the command line"
	sys.exit(1)

input_filename = sys.argv[1]
print("Input file: " + input_filename)
config_bytes = open(input_filename, "rb").read()
print("Read " + str(len(config_bytes)) + " bytes.")
print("Configuring Dipsy...")

r = configure_dipsy(config_bytes)
if r==_STATUS_OK:
	print("Dipsy configured!")
elif r==_STATUS_NOT_DONE:
	print("Error: Dipsy not configured.")
elif r==_STATUS_NOT_PROGRAMMING:
	print("Error: Dipsy didn't enter programming mode.")
else:
	print("Error unknown.")