SPI: connect by VERSION command (#1495)

* SPI: connect by VERSION command

* shorter timeout

* add exception

* simple test

* fallback

* bootstub check

* update comments

---------

Co-authored-by: Comma Device <device@comma.ai>

python/__init__.py

@@ -17,7 +17,7 @@ from .base import BaseHandle
 from .constants import FW_PATH, McuType
 from .dfu import PandaDFU
 from .isotp import isotp_send, isotp_recv
-from .spi import PandaSpiHandle, PandaSpiException
+from .spi import PandaSpiHandle, PandaSpiException, PandaProtocolMismatch
 from .usb import PandaUsbHandle
 
 __version__ = '0.0.10'
@@ -326,16 +326,30 @@ class Panda:
       self.set_power_save(0)
 
   @staticmethod
-  def spi_connect(serial):
+  def spi_connect(serial, ignore_version=False):
     # get UID to confirm slave is present and up
     handle = None
     spi_serial = None
     bootstub = None
+    spi_version = None
     try:
       handle = PandaSpiHandle()
-      dat = handle.controlRead(Panda.REQUEST_IN, 0xc3, 0, 0, 12, timeout=100)
-      spi_serial = binascii.hexlify(dat).decode()
-      bootstub = Panda.flasher_present(handle)
+
+      # connect by protcol version
+      try:
+        dat = handle.get_protocol_version()
+        spi_serial = binascii.hexlify(dat[:12]).decode()
+        pid = dat[13]
+        if pid not in (0xcc, 0xee):
+          raise PandaSpiException("invalid bootstub status")
+        bootstub = pid == 0xee
+        spi_version = dat[14]
+      except PandaSpiException:
+        # fallback, we'll raise a protocol mismatch below
+        dat = handle.controlRead(Panda.REQUEST_IN, 0xc3, 0, 0, 12, timeout=100)
+        spi_serial = binascii.hexlify(dat).decode()
+        bootstub = Panda.flasher_present(handle)
+        spi_version = 0
     except PandaSpiException:
       pass
 
@@ -345,6 +359,12 @@ class Panda:
       spi_serial = None
       bootstub = False
 
+    # ensure our protocol version matches the panda
+    if handle is not None and not ignore_version:
+      if spi_version != handle.PROTOCOL_VERSION:
+        err = f"panda protocol mismatch: expected {handle.PROTOCOL_VERSION}, got {spi_version}. reflash panda"
+        raise PandaProtocolMismatch(err)
+
     return handle, spi_serial, bootstub, None
 
   @staticmethod
@@ -416,7 +436,7 @@ class Panda:
 
   @staticmethod
   def spi_list():
-    _, serial, _, _ = Panda.spi_connect(None)
+    _, serial, _, _ = Panda.spi_connect(None, ignore_version=True)
     if serial is not None:
       return [serial, ]
     return []