flash_can: add usb support

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

lib/canboot/flash_can.py

@@ -496,9 +496,70 @@ class CanSocket:
         self._loop.remove_reader(self.cansock.fileno())
         self.cansock.close()
 
+class SerialSocket:
+    def __init__(self, loop: asyncio.AbstractEventLoop):
+        self._loop = loop
+        self.serial = self.serial_error = None
+        self.node = CanNode(0, self)
+
+    def _handle_response(self) -> None:
+        try:
+            data = self.serial.read(4096)
+        except self.serial_error as e:
+            logging.exception("Error on serial read")
+            self.close()
+        self.node.feed_data(data)
+
+    def send(self, can_id: int, payload: bytes = b"") -> None:
+        try:
+            self.serial.write(payload)
+        except self.serial_error as e:
+            logging.exception("Error on serial write")
+            self.close()
+
+    async def run(self, intf: str, baud: int, fw_path: pathlib.Path) -> None:
+        if not fw_path.is_file():
+            raise FlashCanError("Invalid firmware path '%s'" % (fw_path))
+        import serial
+        self.serial_error = serial.SerialException
+        try:
+            serial_dev = serial.Serial(baudrate=baud, timeout=0,
+                                       exclusive=True)
+            serial_dev.port = intf
+            serial_dev.open()
+        except (OSError, IOError, self.serial_error) as e:
+            raise FlashCanError("Unable to open serial port: %s" % (e,))
+        self.serial = serial_dev
+        self._loop.add_reader(self.serial.fileno(), self._handle_response)
+        flasher = CanFlasher(self.node, fw_path)
+        try:
+            await flasher.connect_btl()
+            await flasher.send_file()
+            await flasher.verify_file()
+        finally:
+            # always attempt to send the complete command. If
+            # there is an error it will exit the bootloader
+            # unless comms were broken
+            await flasher.finish()
+
+    def close(self):
+        if self.serial is None:
+            return
+        self._loop.remove_reader(self.serial.fileno())
+        self.serial.close()
+        self.serial = None
+
 def main():
     parser = argparse.ArgumentParser(
         description="Can Bootloader Flash Utility")
+    parser.add_argument(
+        "-d", "--device", metavar='<serial device>',
+        help="Serial Device"
+    )
+    parser.add_argument(
+        "-b", "--baud", default=250000, metavar='<baud rate>',
+        help="Serial baud rate"
+    )
     parser.add_argument(
         "-i", "--interface", default="can0", metavar='<can interface>',
         help="Can Interface"
@@ -522,27 +583,37 @@ def main():
 
     args = parser.parse_args()
     if not args.verbose:
-        logging.getLogger().setLevel(logging.CRITICAL)
+        logging.getLogger().setLevel(logging.ERROR)
     intf = args.interface
     fpath = pathlib.Path(args.firmware).expanduser().resolve()
     loop = asyncio.get_event_loop()
+    iscan = args.device is None
+    sock = None
     try:
-        cansock = CanSocket(loop)
+        if iscan:
+            sock = CanSocket(loop)
             if args.query:
-            loop.run_until_complete(cansock.run_query(intf))
+                loop.run_until_complete(sock.run_query(intf))
             else:
                 if args.uuid is None:
                     raise FlashCanError(
                         "The 'uuid' option must be specified to flash a device"
                     )
                 uuid = int(args.uuid, 16)
-            loop.run_until_complete(cansock.run(intf, uuid, fpath))
+                loop.run_until_complete(sock.run(intf, uuid, fpath))
+        else:
+            if args.device is None:
+                raise FlashCanError(
+                    "The 'device' option must be specified to flash a device"
+                )
+            sock = SerialSocket(loop)
+            loop.run_until_complete(sock.run(args.device, args.baud, fpath))
     except Exception as e:
         logging.exception("Can Flash Error")
         sys.exit(-1)
     finally:
-        if cansock is not None:
+        if sock is not None:
-            cansock.close()
+            sock.close()
     if args.query:
         output_line("Query Complete")
     else: