#!/usr/bin/python
#
#  spreadspace pic utils
#
#
#  Copyright (C) 2011-2013 Christian Pointner <equinox@spreadspace.org>
#
#  This file is part of spreadspace pic utils.
#
#  spreadspace pic utils is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  any later version.
#
#  spreadspace pic utils is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with spreadspace pic utils. If not, see <http://www.gnu.org/licenses/>.
#

'''spreadspace simple pic downloader.'''

VERSION_MAJ = 1
VERSION_MIN = 0

### HEX File Magic

def load_hex(file):
    from ihexpic import IHexPic
    import os

    fin = file
    if fin == '-':
        fin = sys.stdin
    elif not os.path.isfile(fin):
        print >> sys.stderr, "ERROR: File not found: %s" % fin
        sys.exit(1)

    hexdata = IHexPic()
    hexdata.load_from_file(fin)
    return hexdata

def write_hex(file, codedata):
    from ihexpic import IHexPic

    fout = file
    if fout == '-':
        fout = sys.stdout

    hexdata = IHexPic()
    hexdata.load_from_dict(codedata)
    hexdata.write_to_file(fout)

def get_lowest_flash_addr(hexdata, fss):
    lowest_code_addr = hexdata.get_lowest_addr()
    return lowest_code_addr - (lowest_code_addr%fss)

def get_highest_flash_addr(hexdata, fss):
    highest_code_addr = hexdata.get_highest_addr()
    return highest_code_addr + (fss - highest_code_addr%fss)

def create_flash_image(hexdata, fss, sa, ea):
    img = ( sa, [0xFFFF]*(ea-sa) )
    for a,d in hexdata.items():
        if a < ea:
            img[1][a-sa] = d
    return img

def create_flash_segments(hexdata, fs, fss):
    sa = get_lowest_flash_addr(hexdata, fss)
    ea = get_highest_flash_addr(hexdata, fss)
    if ea >= fs:
        print >> sys.stderr, "WARNING: the hex file contains data after end of flash, these words will be ignored"
        ea = fs

    img = create_flash_image(hexdata, fss, sa, ea)
    for i in xrange(0, ea, fss):
        slice = tuple(img[1][i:i+fss])
        if not all( (elem == 0xFFFF) for elem in slice):
            yield (i + img[0], slice)


### Interface to Bootloader

def open_serial(device, baud):
    import serial
    import time

    print >> sys.stderr,  "opening %s (%s Baud)" % (device, baud)

    try:
        dev = serial.Serial(port=device, baudrate=baud, timeout=3)
        dev.flushInput()
        dev.flushOutput()
        dev.setDTR(True)    # send a reset pulse
        dev.setBreak(True)  # boot into bootloader
        time.sleep(0.1)
        dev.setDTR(False)
        time.sleep(0.01)
        dev.setBreak(False)
        return dev

    except (ValueError, serial.SerialException), msg:
        print >> sys.stderr, "ERROR: opening serial device: %s" % msg
        sys.exit(3)

def calc_csum(str):
    cs = 0
    for c in str:
        cs ^= c
    return cs

def exec_command(dev, cmd, param, answer):

    return_codes = { 0: "OK", 1: "invalid command", 2: "bad checksum",
                     3: "not implemented", 4: "flash write error",
                     5: "address invalid", 6: "address prohibited",
                     7: "value out of bounds" }

    dev.flushInput()
    dev.flushOutput()

    cstr = bytearray(struct.pack('<BB', cmd, len(param)+3) + param)
    cstr.extend(struct.pack("<B", calc_csum(cstr)))
    dev.write(cstr)

    astr = bytearray()
    astr += dev.read(4)
    if len(astr) < 4:
        print >> sys.stderr, "ERROR: timeout while reading response header (expected %d bytes, got %d)" % (4, len(astr))
        sys.exit(4)

    if astr[0] != cstr[0]:
        print >> sys.stderr, "ERROR: bootloader returned wrong command code"
        sys.exit(4)

    ret = astr[2]
    if ret != 0:
        rstr = "invalid return code"
        try:
            rstr = return_codes[ret]
        except KeyError:
            pass
        print >> sys.stderr, "ERROR: bootloader returned %d: %s" % (ret, rstr)
        sys.exit(4)

    answer_len = astr[1] - 4
    if answer_len < struct.calcsize(answer):
        print >> sys.stderr, "ERROR: short answer %d bytes received: expected %s bytes" % (answer_len, struct.calcsize(answer))
        sys.exit(4)

    if answer_len > 0:
        tmp = bytearray()
        tmp += dev.read(answer_len)
        if len(tmp) < answer_len:
            print >> sys.stderr, "ERROR: timeout while reading response (expected %d bytes, got %d)" % (answer_len, len(tmp))
            sys.exit(4)

        astr += tmp

    if 0 != calc_csum(astr):
        print >> sys.stderr, "ERROR: checksum error"
        sys.exit(4)

    return struct.unpack_from(answer, astr, 3)

### low level commands

def cmd_identify(dev, name):
    data = exec_command(dev, 1, '', '<BB3sHHBHBB')
    id = { 'ver_min': data[0], 'ver_maj': data[1], 'name': data[2], 'devid': data[3],
           'fs': data[4], 'fss': data[5], 'es': data[6], 'mess': data[7], 'cfg': data[8] }

    if id['ver_maj'] != VERSION_MAJ:
        print >> sys.stderr, "incompatible protocol version, expected: %d, got: %d" % (VERSION_MAJ, id['ver_maj'])
        sys.exit(4)
    if name and id['name'] != name:
        print >> sys.stderr, "ERROR: the bootloaders name '%s' differs from the one supplied via" % id['name']
        print >> sys.stderr, "       command line option '%s'. Are sure you are connected to the" % name
        print >> sys.stderr, "       right device?"
        sys.exit(4)

    print >> sys.stderr, "connected with Bootloader '%s' Version %d.%d,\n  (ID=%04X, %d words Flash, FSS=%d, %d bytes EEPROM, MESS=%d, %d words Config)\n" % \
        (id['name'], id['ver_maj'], id['ver_min'], id['devid'], id['fs'], id['fss'], id['es'], id['mess'], id['cfg'])
    return id

def cmd_boot(dev):
    exec_command(dev, 2, '', '<')

def cmd_reset(dev, id):
    exec_command(dev, 3, '', '<')

def cmd_read_flash_segment(dev, id, addr):
    param = struct.pack('<H', addr)
    return exec_command(dev, 4, param, '<%dH' % id['fss'])

def cmd_write_flash_segment(dev, id, addr, data):
    param = struct.pack('<H%dH' % id['fss'], addr, *data)
    return exec_command(dev, 5, param, '<')

def cmd_read_eeprom(dev, id, addr, len):
    param = struct.pack('<HB', addr, len)
    return exec_command(dev, 6, param, '<%dB' % len)

def cmd_write_eeprom(dev, id, addr, data):
    param = struct.pack('<HB%dB' % len(data), addr, len(data), *data)
    return exec_command(dev, 7, param, '<')

def cmd_read_config(dev, id, nr):
    param = struct.pack('<B', nr)
    data = exec_command(dev, 8, param, '<H')
    return data[0]

def cmd_write_config(dev, id, nr, word):
    param = struct.pack('<BH', nr, word)
    return exec_command(dev, 9, param, '<')


### utils

class progressbar(object):
    def __init__(self, total, name, size=50):
        self._name = name
        self._cnt = 0.0
        self._total = float(total)
        self._point = total / 100.0
        self._size = size
        self._increment = total / float(self._size)
        self._update()

    def _update(self):
        sys.stderr.write('\r %13s' % self._name)
        val = int(self._cnt / self._increment)
        sys.stderr.write(' [' + '=' * val  + ' ' * (self._size-val) + ']')
        sys.stderr.write(' {:3.0f}'.format((self._cnt / self._point)) + '%')
#        sys.stderr.write(' ( %d / %d )' % (self._cnt, self._total))
        sys.stderr.flush()

    def increment(self):
        self._cnt += 1.0
        self._update()

    def end(self):
        self._cnt = self._total
        self._update()
        sys.stderr.write("\n")


### commands

def boot(dev, id, args):
    print >> sys.stderr, "booting to user code"
    cmd_boot(dev)

def reset(dev, id, args):
    print >> sys.stderr, "reseting MCU"
    cmd_reset(dev,id)

def write_flash(dev, id, args):
    hexdata = load_hex(args[0])
    flashsegments = list(create_flash_segments(hexdata, id['fs'], id['fss']))
    print >> sys.stderr, "writing to flash from '%s'" % args[0]
    bar = progressbar(len(flashsegments), "write flash")
    for segment in flashsegments:
        cmd_write_flash_segment(dev, id, segment[0], segment[1])
        bar.increment()
    bar.end()
    print >> sys.stderr, ""

def read_flash(dev, id, args):
    codedata = {}
    print >> sys.stderr, "reading flash to '%s'" % args[0]
    bar = progressbar(float(id['fs'])/float(id['fss']), "read flash")
    for addr in xrange(0, id['fs'], id['fss']):
        data = cmd_read_flash_segment(dev, id, addr)
        bar.increment()
        a = addr
        for d in data:
            if d != 0x3FFF:
                codedata[a] = d
            a += 1
    bar.end()
    write_hex(args[0], codedata)
    print >> sys.stderr, ""

def verify_flash(dev, id, args):
    hexdata = load_hex(args[0])
    err = 0
    flashsegments = list(create_flash_segments(hexdata, id['fs'], id['fss']))
    print >> sys.stderr, "comparing flash with '%s'" % args[0]
    bar = progressbar(len(flashsegments), "verify flash")
    for segment in flashsegments:
        flashdata = cmd_read_flash_segment(dev, id, segment[0])
        bar.increment()
        for file,flash in zip(segment[1] , flashdata):
            if flash == 0x3FFF:
                flash = 0xFFFF
            if flash != file:
                err = 1
                break

        if err !=0:
            break
    bar.end()
    print >> sys.stderr, ""
    if err != 0:
        print >> sys.stderr, "     ********* verify failed! ******** .. exiting"
        sys.exit(-1)
    else:
        print >> sys.stderr, "     *********** verify ok! **********\n"

def read_config(dev, id, args):
    nr = int(args[0])
    print >> sys.stderr, "reading configuration word nr %d" % nr
    print "0x%04X" % cmd_read_config(dev, id, nr)


commands = {
    'boot': boot,
    'reset': reset,
    'write': write_flash,
    'read': read_flash,
    'verify': verify_flash,
    'read-config': read_config
}

### Main

if __name__ == '__main__':
    import getopt
    import sys
    import struct

    usage = '''spreadspace simple pic downloader.
Usage:
    python downloader.py [options] command [ command2 [ .. ] ]

    You can supply as many commands as you wish. Any command except 'boot'
    may be supplied more than once. The commands will be executed in the
    order of appearence at command line.
    Mind that all commands after 'boot' will be ignored because the bootloader
    is no longer reachable. The same may be true after a reset in which case,
    depending on the state of BOOTPIN, the user code may get started.
    If verify detects an error the downloader will exit with '-1' immediatly and
    the remaining commands will get ignored.
    If you don't specify any command the downloader will connect to the
    bootloader print some information and exit.

Options:
    -h, --help              this help message.
    -v, --version           version info.
    --device=N              the serial port to use (default: /dev/ttyUSB0).
    --baud=N                baudrate to use (default: 57600).
    --name=N                the expected name of the bootloader.

Commands:
    --write=<hexfile>       write <hexfile> to flash (use '-' for stdin).
    --verify=<hexfile>      compare flash with <hexfile> (use '-' for stdin).
    --read=<hexfile>        read flash and store in <hexfile> (use '-' for stdout).
    --read-config=<nr>      read the configuration word <nr> and print it on stdout.
    --reset                 reset the MCU (this may start the user code area: BOOTPIN)
    --boot                  boot to user code
'''

    device = "/dev/ttyUSB0"
    baudrate = 57600
    name = None
    cmds = []

    try:
        opts, args = getopt.getopt(sys.argv[1:], "hv", ["help", "version", "device=", "baud=", "name=", \
                                                            "write=", "read=", "verify=", "read-config=", "reset", "boot" ])
        for o, a in opts:
            if o in ("-h", "--help"):
                print >> sys.stderr, usage
                sys.exit(0)
            elif o in ("-v", "--version"):
                print >> sys.stderr, "Version %d.%d" % (VERSION_MAJ, VERSION_MIN)
                sys.exit(0)
            elif o == "--device":
                device = a
            elif o == "--baud":
                baudrate = a
            elif o == "--name":
                name = a
            else:
                cmds.append({ 'name': o[2:], 'args': a.split(':') });

        if len(args) > 1:
            raise getopt.GetoptError('Too many arguments')

        if len(cmds) == 0:
            print "WARNING: no commands specified"
            sys.exit

    except getopt.GetoptError, msg:
        print >> sys.stderr, "ERROR: %s" % msg
        print >> sys.stderr, usage
        sys.exit(2)

    dev = open_serial(device, baudrate)
    id = cmd_identify(dev, name)

    try:
        for cmd in cmds:
            commands[cmd['name']](dev, id, cmd['args'])
    except KeyError:
        print >> sys.stderr, "ERROR: unknown command '%s'" % cmd['name']