tools: add dfu-suffix.py

This reproduces `dfu-suffix` from the `dfu-tools` package.

Signed-off-by: Sean Cross <sean@xobs.io>

tools/dfu-suffix.py

@@ -0,0 +1,95 @@
+#!/usr/bin/python
+
+# Written by Antonio Galea - 2010/11/18
+# Updated for DFU 1.1 by Sean Cross - 2020/03/31
+# Distributed under Gnu LGPL 3.0
+# see http://www.gnu.org/licenses/lgpl-3.0.txt
+
+import sys,struct,zlib,os
+from optparse import OptionParser
+
+DEFAULT_DEVICE="0x0483:0xdf11"
+
+def named(tuple,names):
+  return dict(zip(names.split(),tuple))
+def consume(fmt,data,names):
+  n = struct.calcsize(fmt)
+  return named(struct.unpack(fmt,data[:n]),names),data[n:]
+def cstring(string):
+  return string.split('\0',1)[0]
+def compute_crc(data):
+  return 0xFFFFFFFF & -zlib.crc32(data) -1
+
+def parse(file,dump_images=False):
+  print ('File: "%s"' % file)
+  data = open(file,'rb').read()
+  crc = compute_crc(data[:-4])
+  data = data[len(data)-16:]
+  suffix = named(struct.unpack('<4H3sBI',data[:16]),'device product vendor dfu ufd len crc')
+  print ('usb: %(vendor)04x:%(product)04x, device: 0x%(device)04x, dfu: 0x%(dfu)04x, %(ufd)s, %(len)d, 0x%(crc)08x' % suffix)
+  if crc != suffix['crc']:
+    print ("CRC ERROR: computed crc32 is 0x%08x" % crc)
+  data = data[16:]
+  if data:
+    print ("PARSE ERROR")
+
+def build(file,data,device=DEFAULT_DEVICE):
+  # Parse the VID and PID from the `device` argument
+  v,d=map(lambda x: int(x,0) & 0xFFFF, device.split(':',1))
+
+  # Generate the DFU suffix, consisting of these fields:
+  #  Field name     | Length  |  Description
+  # ================+=========+================================
+  #  bcdDevice      |    2    | The release number of this firmware (0xffff - don't care)
+  #  idProduct      |    2    | PID of this device
+  #  idVendor       |    2    | VID of this device
+  #  bcdDFU         |    2    | Version of this DFU spec (0x01 0x00)
+  #  ucDfuSignature |    3    | The characters 'DFU', printed in reverse order
+  #  bLength        |    1    | The length of this suffix (16 bytes)
+  #  dwCRC          |    4    | A CRC32 of the data, including this suffix
+  data += struct.pack('<4H3sB',0xffff,d,v,0x0100,b'UFD',16)
+  crc   = compute_crc(data)
+  # Append the CRC32 of the entire block
+  data += struct.pack('<I',crc)
+  open(file,'wb').write(data)
+
+if __name__=="__main__":
+  usage = """
+%prog [-d|--dump] infile.dfu
+%prog {-b|--build} file.bin [{-D|--device}=vendor:device] outfile.dfu"""
+  parser = OptionParser(usage=usage)
+  parser.add_option("-b", "--build", action="store", dest="binfile",
+    help="build a DFU file from given BINFILE", metavar="BINFILE")
+  parser.add_option("-D", "--device", action="store", dest="device",
+    help="build for DEVICE, defaults to %s" % DEFAULT_DEVICE, metavar="DEVICE")
+  parser.add_option("-d", "--dump", action="store_true", dest="dump_images",
+    default=False, help="dump contained images to current directory")
+  (options, args) = parser.parse_args()
+
+  if options.binfile and len(args)==1:
+    binfile = options.binfile
+    if not os.path.isfile(binfile):
+      print ("Unreadable file '%s'." % binfile)
+      sys.exit(1)
+    target = open(binfile,'rb').read()
+    outfile = args[0]
+    device = DEFAULT_DEVICE
+    # If a device is specified, parse the pair into a VID:PID pair
+    # in order to validate them.
+    if options.device:
+      device=options.device
+    try:
+      v,d=map(lambda x: int(x,0) & 0xFFFF, device.split(':',1))
+    except:
+      print ("Invalid device '%s'." % device)
+      sys.exit(1)
+    build(outfile,target,device)
+  elif len(args)==1:
+    infile = args[0]
+    if not os.path.isfile(infile):
+      print ("Unreadable file '%s'." % infile)
+      sys.exit(1)
+    parse(infile, dump_images=options.dump_images)
+  else:
+    parser.print_help()
+    sys.exit(1)