#!/usr/bin/env python
#
# Copyright 2010-2012 Michael Ossmann, Travis Goodspeed
#
# This file is forked from Project Ubertooth in order to support the
# STM32F2xx.
#
# This program 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 2, or (at your option)
# any later version.
#
# This program 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 this program; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.

# The STM32 series of ARM chips implement a weird variant of DFU, so
# I've written this client in order to understand it.  Sometime in the
# future, I expect to build a general-purpose DFU tool that works for
# all chips.  For now, though, this will certainly not be expected to
# run on anything but the STM32 series.

# http://pyusb.sourceforge.net/docs/1.0/tutorial.html

import struct
import sys
import time
from optparse import OptionParser

stm32_vendor   = 0x0483
stm32_product  = 0xdf11

ram_offset = 0x20002000 #RAM
ram_size=0x1E000
application_offset = 0x08000000 #Flash
application_size = 0x100000  #1MB
rom_offset = 0x1fff0000 #ROM
rom_size = 0x8000  #32K
otp_offset = 0x1fff7800 #OTP ROM
otp_size = 512


#Smaller block sizes cause problems. Not sure why.
block_size=2048

class Enumeration(object):
    def __init__(self, id, name):
        self._id = id
        self._name = name
        setattr(self.__class__, name, self)
        self.map[id] = self

    def __int__(self):
        return self.id

    def __repr__(self):
        return self.name

    @property
    def id(self):
        return self._id

    @property
    def name(self):
        return self._name

    @classmethod
    def create_from_map(cls):
        for id, name in cls.map.iteritems():
            cls(id, name)
        
class Request(Enumeration):
    map = {
        0: 'DETACH',
        1: 'DNLOAD',
        2: 'UPLOAD',
        3: 'GETSTATUS',
        4: 'CLRSTATUS',
        5: 'GETSTATE',
        6: 'ABORT',
    }

Request.create_from_map()

class State(Enumeration):
    map = {
         0: 'appIDLE',
         1: 'appDETACH',
         2: 'dfuIDLE',
         3: 'dfuDNLOAD_SYNC',
         4: 'dfuDNBUSY',
         5: 'dfuDNLOAD_IDLE',
         6: 'dfuMANIFEST_SYNC',
         7: 'dfuMANIFEST',
         8: 'dfuMANIFEST_WAIT_RESET',
         9: 'dfuUPLOAD_IDLE',
        10: 'dfuERROR',
    }

State.create_from_map()

class Status(Enumeration):
    map = {
        0x00: 'OK',
        0x01: 'errTARGET',
        0x02: 'errFILE',
        0x03: 'errWRITE',
        0x04: 'errERASE',
        0x05: 'errCHECK_ERASED',
        0x06: 'errPROG',
        0x07: 'errVERIFY',
        0x08: 'errADDRESS',
        0x09: 'errNOTDONE',
        0x0A: 'errFIRMWARE',
        0x0B: 'errVENDOR',
        0x0C: 'errUSBR',
        0x0D: 'errPOR',
        0x0E: 'errUNKNOWN',
        0x0F: 'errSTALLEDPKT',
    }

Status.create_from_map()

class DFU(object):
    def __init__(self, device):
        self._device = device

    def detach(self):
        self._device.ctrl_transfer(0x21, Request.DETACH, 0, 0, None)

    def download(self, block_number, data):
        """Download a block to RAM or Flash."""
        self._device.ctrl_transfer(0x21, Request.DNLOAD, block_number, 0, data)
    def masserase(self):
        """Mass erase all of Flash memory.  OTP left intact."""
        self._device.ctrl_transfer(bmRequestType=0x21,
                                   bRequest=Request.DNLOAD,
                                   wValue=0,
                                   wIndex=0,
                                   data_or_wLength=[0x41]);
        # Erasure doesn't occur until we check the status.
        status=self.get_status();
        
        print "The device is now erasing itself.";
        print "This will result in a USB disconnect.";
        return True;
    def go(self,address=0x08000000):
        """Branch to the address at addrptr+4."""
        
        #Branches to the value stored at the word *AFTER* this address.
        self.setaddresspointer(address);
        
        #Use DNLOAD, not DETACH.
        self._device.ctrl_transfer(bmRequestType=0x21,
                                   bRequest=Request.DNLOAD,
                                   #bRequest=Request.DETACH,
                                   wValue=0,
                                   wIndex=0,
                                   data_or_wLength=[]);  #Zero length.
        # Execution.
        print self.get_status();
        
        
        print "The device is now executing its application.";
        print "This will result in a USB disconnect.";
        return True;
    def readprotect(self):
        """Over the control word to protect the chip."""
        #Option byte address.
        adr=0x1fffc000;
        self.setaddresspointer(adr);
        
        # #Grab the old block.
        # data=self.upload(2,2);
        # #Second read verifies the state.
        # status, timeout, state, discarded = dfu.get_status()
        # print state;
        # assert state==State.dfuUPLOAD_IDLE
        
        
        # print "Grabbing old option bytes.";
        # for foo in data:
        #     print "%02x" % foo;
        
        #Write the new block.
        #self._device.ctrl_transfer(0x21, Request.DNLOAD, 2, 0, [0xFF, 0xAA, 0x00, 0x55])
        self.download(2,[0xFF,0xFF]);
        
        #status check causes the write
        status, timeout, state, discarded = dfu.get_status()
        assert state==State.dfuDNBUSY;
            
        
    def readunprotect(self):
        """Mass erase all of Flash memory.  OTP left intact."""
        self._device.ctrl_transfer(bmRequestType=0x21,
                                           bRequest=Request.DNLOAD,
                                           wValue=0,
                                           wIndex=0,
                                           data_or_wLength=[0x92]);
        
        print "Unprotecting the device.";
        print "This will cause a USB disconnection.";
        status=self.get_status();
        
        return True;
        
        
    def upload(self, block_number, length):
        # 2 to 2048 byte size for Flash, RAM, and System memory.
        # option bytes should be equal to option byte block size.
        # Other locations defined in Important Considerations in AN2606
        
        #Address_Pointer is expected to have been already set by 
        #Address = ((wBlockNum - 2) * wTransferSize) + Address_Pointer,
        
        #print "Requesting block 0x%08x size %06x" % (block_number,length);
        
        if block_number>0xFFFF:
            print "WARNING: Block 0x%04x will be returned instead. (16-bit addr.)" % (block_number&0xFFFF);
        
        #data = self._device.ctrl_transfer(0xA1, Request.UPLOAD, block_number, 0, length)
        data = self._device.ctrl_transfer(bmRequestType=0xA1,
                                          bRequest=Request.UPLOAD,
                                          wValue=block_number,
                                          wIndex=0,
                                          data_or_wLength=length)
        return data
    def setaddresspointer(self, address=application_offset):
        """Sets the address pointer in the STM32."""
        
        byte0=address&0xFF;
        byte1=(address>>8)&0xFF;
        byte2=(address>>16)&0xFF;
        byte3=(address>>24)&0xFF;
        
        
        data=[0x21,                     #Set pointer op-code
              byte0,byte1,byte2,byte3   #Address, little-endian.
              ];
        #print self.get_status();
        toret = self._device.ctrl_transfer(bmRequestType=0x21,
                                           bRequest=Request.DNLOAD,
                                           wValue=0,
                                           wIndex=0,
                                           data_or_wLength=data);
        # Address isn't set until first GETSTATUS query.
        status=self.get_status();
        
        # Second query is needed to check if correctly set.
        # Failures result in dfuERROR or errTARGET.
        status=self.get_status();
        
        if status[2]==State.dfuDNLOAD_IDLE:
            print "Setting address pointer to 0x%08x." % address;
            #This will get us back to the entry point.
            self.enter_dfu_mode();
        else:
            print "Failed to set address pointer.";
            return False;
        return True;
        
    def get_status(self):
        status_packed = self._device.ctrl_transfer(0xA1, Request.GETSTATUS, 0, 0, 6)
        status = struct.unpack('<BBBBBB', status_packed)
        return (Status.map[status[0]], (((status[1] << 8) | status[2]) << 8) | status[3],
                State.map[status[4]], status[5])

    def clear_status(self):
        self._device.ctrl_transfer(0x21, Request.CLRSTATUS, 0, 0, None)

    def get_state(self):
        state_packed = self._device.ctrl_transfer(0xA1, Request.GETSTATE, 0, 0, 1)
        return State.map[struct.unpack('<B', state_packed)[0]]

    def abort(self):
        self._device.ctrl_transfer(0x21, Request.ABORT, 0, 0, None)

    def enter_dfu_mode(self):
        action_map = {
            State.dfuDNLOAD_SYNC: self.abort,
            State.dfuDNLOAD_IDLE: self.abort,
            State.dfuMANIFEST_SYNC: self.abort,
            State.dfuUPLOAD_IDLE: self.abort,
            State.dfuERROR: self.clear_status,
            State.appIDLE: self.detach,
            State.appDETACH: self._wait,
            State.dfuDNBUSY: self._wait,
            State.dfuMANIFEST: self.abort,
            State.dfuMANIFEST_WAIT_RESET: self._wait,
            State.dfuIDLE: self._wait
        }
        
        while True:
            state = self.get_state()
            if state == State.dfuIDLE:
                break
            action = action_map[state]
            action()

    def _wait(self):
        time.sleep(0.1)

def download(dfu, data, flash_address):
    #block_size = 1 << 8
    sector_size = 1 << 12
    
    print "Flashing to 0x%08x" % flash_address;
    
    base_address=flash_address;
    
    #Rebase the address pointer.
    if not dfu.setaddresspointer(base_address):
        print "Failed to set address."
        sys.exit(1);
    
    flash_address= flash_address+block_size*2-base_address  #Correct offset.
    
    
    if flash_address & (sector_size - 1) != 0:
        raise Exception('Download must start at flash sector boundary')

    block_number = flash_address / block_size
    assert block_number * block_size == flash_address

    
    print "Based from  0x%08x" % base_address;
    
    try:
        while len(data) > 0:
            packet, data = data[:block_size], data[block_size:]
            if len(packet) < block_size:
                print "Padding a short packet.";
                packet += '\xFF' * (block_size - len(packet))
            #print "Downloading block %i." % block_number;
            dfu.download(block_number, packet)
            
            #status check causes the write
            status, timeout, state, discarded = dfu.get_status()
            assert state==State.dfuDNBUSY;
            
            #Second read verifies the state.
            status, timeout, state, discarded = dfu.get_status()
            assert state==State.dfuDNLOAD_IDLE
            
            sys.stdout.write('.')
            sys.stdout.flush()
            block_number += 1
    finally:
        print
    dfu.enter_dfu_mode();

def upload(dfu, flash_address, length, path):
    """Uploads a region from the chip to a file on the workstation."""
    
    #Set the base address, then make it zero.
    base_address=flash_address;
    #flash_address=base_address;
    
    #Rebase the address pointer.
    if not dfu.setaddresspointer(base_address):
        print "Failed to set address."
        sys.exit(1);
    
    flash_address= flash_address+block_size*2-base_address  #Correct offset.
    
    if flash_address & (block_size - 1) != 0:
        raise Exception('Upload must start at block boundary')

    block_number = flash_address / block_size
    #assert block_number * block_size == flash_address   #Ubertooth, not STM32
    #address_pointer=0;
    #assert flash_address==((block_number-2)*block_size)+address_pointer;

    print "flash_address = %08x" % flash_address;
    print "block_number  = %08x" % block_number;
    print "block_size    = %08x" % block_size;

    f = open(path, 'wb')
   
    try:
        while length > 0:
            data = dfu.upload(block_number, block_size)
            status, timeout, state, discarded = dfu.get_status()
            sys.stdout.write('.')
            sys.stdout.flush()
            if len(data) == block_size:
                f.write(data)
                block_number += 1
                length -= len(data)
            else:
                #raise Exception('Upload failed to read full block')
                print "Failed to return full block number 0x%x" % block_number
                print "Got 0x%i bytes." % len(data);
    finally:
        f.close()
        print
def detach(dfu):
    if dfu.get_state() == State.dfuIDLE:
        dfu.detach()
        print('Detached')
    else:
        print 'In unexpected state: %s' % dfu.get_state()

def init_dfu(idVendor=stm32_vendor, idProduct=stm32_product):
    dev = usb.core.find(idVendor=idVendor, idProduct=idProduct)
    if dev is None:
        raise RuntimeError('Device not found')

    dfu = DFU(dev)
    dev.default_timeout = 3000

    try:
        dfu.enter_dfu_mode()
    except usb.core.USBError, e:
        if len(e.args) > 0 and e.args[0] == 'Pipe error':
            raise RuntimeError('Failed to enter DFU mode. Is bootloader running?')
        else:
            raise e

    return dfu

def usage():
    print("""
Usage: stm32-dfu <command> <arguments>

Write a file to application flash region:
    stm32-dfu writeflash $file
Write a file to RAM at 0x20002000, after DFU region.
    stm32-dfu writeram $file
Write a file to an arbitrary address.
    stm32-dfu write $file $adr

Read data from application flash region and write to a file:
    stm32-dfu read <filename>
Read data from SRAM region and write to a file:
    stm32-dfu readram <filename>
Read data from ROM region and write to a file:
    stm32-dfu readrom <filename>
Read data from OTP region and write to a file:
    stm32-dfu readotp <filename>

Mass erase STM32 in preparation for reflashing.
    stm32-dfu erase
Unprotect the STM32's RDP.
    stm32-dfu unprotect
Protect the STM32's RDP.
    stm32-dfu protect

Detach the bootloader and execute the flash application.
    stm32-dfu go [0x08000000]
Detach the bootloader and execute from RAM at 0x20002000.
    stm32-dfu goram

""")

if __name__ == '__main__':
    if len(sys.argv)>1:
            if sys.argv[1] == 'read':
                import usb.core
                dfu = init_dfu()
                upload(dfu, application_offset, application_size, sys.argv[2])
                print('Read complete')
            elif sys.argv[1] == 'readram':
                import usb.core
                dfu = init_dfu()
                upload(dfu, ram_offset, ram_size, sys.argv[2])
                print('Read complete')
            elif sys.argv[1] == 'readrom':
                import usb.core
                dfu = init_dfu()
                upload(dfu, rom_offset, rom_size, sys.argv[2])
                print('Read complete')
            elif sys.argv[1] == 'readotp':
                import usb.core
                dfu = init_dfu()
                upload(dfu, otp_offset, otp_size, sys.argv[2])
                print('Read complete')
            elif sys.argv[1]=='write':
                import usb.core
                f = open(sys.argv[2], 'rb')
                data = f.read()
                f.close()
                
                dfu = init_dfu()
                firmware = data
                application_offset=int(sys.argv[3],16);
                
                download(dfu, firmware, application_offset)
                print('Write complete')
            elif sys.argv[1]=='writeflash':
                import usb.core
                f = open(sys.argv[2], 'rb')
                data = f.read()
                f.close()
                
                dfu = init_dfu()
                firmware = data
                
                download(dfu, firmware, application_offset)
                print('Write complete')
            elif sys.argv[1]=='writeram':
                import usb.core
                f = open(sys.argv[2], 'rb')
                data = f.read()
                f.close()
                
                dfu = init_dfu()
                firmware = data
                
                download(dfu, firmware, 0x20002000)
                print('Write complete')
            
            elif sys.argv[1] == 'detach':
                import usb.core;
                dfu = init_dfu();
                detach(dfu);
            elif sys.argv[1] == 'erase':
                import usb.core
                dfu = init_dfu();
                dfu.masserase();
            elif sys.argv[1] == 'go':
                import usb.core
                dfu = init_dfu();
                if len(sys.argv)==2:
                    dfu.go();
                else:
                    dfu.go(int(sys.argv[2],16));
            elif sys.argv[1] == 'unprotect':
                import usb.core
                dfu = init_dfu();
                dfu.readunprotect();
            elif sys.argv[1] == 'protect':
                import usb.core
                dfu = init_dfu();
                dfu.readprotect();
            else:
                usage();
    else:
        usage();