SPI: connect by serial/UID (#1213)

* SPI: connect by serial/UID

* cleanup

* not everyone can have spi

* fix that

* move that

* mypy fix

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

python/__init__.py

@@ -7,7 +7,6 @@ import struct
 import hashlib
 import binascii
 import datetime
-import traceback
 import warnings
 import logging
 from functools import wraps
@@ -17,7 +16,7 @@ from itertools import accumulate
 from .config import DEFAULT_FW_FN, DEFAULT_H7_FW_FN, SECTOR_SIZES_FX, SECTOR_SIZES_H7
 from .dfu import PandaDFU, MCU_TYPE_F2, MCU_TYPE_F4, MCU_TYPE_H7
 from .isotp import isotp_send, isotp_recv
-from .spi import SpiHandle
+from .spi import SpiHandle, PandaSpiException
 
 __version__ = '0.0.10'
 
@@ -227,7 +226,7 @@ class Panda:
   FLAG_GM_HW_CAM = 1
   FLAG_GM_HW_CAM_LONG = 2
 
-  def __init__(self, serial: Optional[str] = None, claim: bool = True, spi: bool = False, disable_checks: bool = True):
+  def __init__(self, serial: Optional[str] = None, claim: bool = True, disable_checks: bool = True):
     self._serial = serial
     self._disable_checks = disable_checks
 
@@ -237,7 +236,6 @@ class Panda:
     self.can_rx_overflow_buffer = b''
 
     # connect and set mcu type
-    self._spi = spi
     self.connect(claim)
 
     # reset comms
@@ -258,15 +256,10 @@ class Panda:
       self.close()
     self._handle = None
 
-    if self._spi:
-      self._handle = SpiHandle()
-
-      # TODO implement
-      self._serial = "SPIDEV"
-      self.bootstub = False
-
-    else:
-      self.usb_connect(claim=claim, wait=wait)
+    # try USB first, then SPI
+    self.usb_connect(claim=claim, wait=wait)
+    if self._handle is None:
+      self.spi_connect()
 
     assert self._handle is not None
     self._mcu_type = self.get_mcu_type()
@@ -278,6 +271,23 @@ class Panda:
       self.set_heartbeat_disabled()
       self.set_power_save(0)
 
+  def spi_connect(self):
+    # get UID to confirm slave is present and up
+    spi_serial = None
+    try:
+      self._handle = SpiHandle()
+      spi_serial = self.get_uid()
+    except PandaSpiException:
+      pass
+
+    if spi_serial is not None and ((self._serial is None) or (self._serial == spi_serial)):
+      self._serial = spi_serial
+      # TODO: detect this
+      self.bootstub = False
+    else:
+      # failed to connect
+      self._handle = None
+
   def usb_connect(self, claim=True, wait=False):
     context = usb1.USBContext()
     while 1:
@@ -288,9 +298,10 @@ class Panda:
               this_serial = device.getSerialNumber()
             except Exception:
               continue
+
             if self._serial is None or this_serial == self._serial:
               self._serial = this_serial
-              print("opening device", self._serial, hex(device.getProductID()))
+              logging.debug("opening device %s %s", this_serial, hex(device.getProductID()))
               self.bootstub = device.getProductID() == 0xddee
               self._handle = device.open()
               if sys.platform not in ("win32", "cygwin", "msys", "darwin"):
@@ -305,9 +316,8 @@ class Panda:
                 self._bcd_device = bytearray([bcd >> 8, ])
 
               break
-      except Exception as e:
-        print("exception", e)
-        traceback.print_exc()
+      except Exception:
+        logging.exception("USB connect error")
       if not wait or self._handle is not None:
         break
       context = usb1.USBContext()  # New context needed so new devices show up
@@ -349,8 +359,6 @@ class Panda:
     if not success:
       raise Exception("reconnect failed")
 
-
-
   @staticmethod
   def flash_static(handle, code, mcu_type):
     assert mcu_type is not None, "must set valid mcu_type to flash"

python/spi.py

@@ -1,3 +1,4 @@
+import os
 import fcntl
 import math
 import time
@@ -24,10 +25,15 @@ MAX_XFER_RETRY_COUNT = 5
 
 USB_MAX_SIZE = 0x40
 
+DEV_PATH = "/dev/spidev0.0"
+
 
 class PandaSpiException(Exception):
   pass
 
+class PandaSpiUnavailable(PandaSpiException):
+  pass
+
 class PandaSpiNackResponse(PandaSpiException):
   pass
 
@@ -52,8 +58,10 @@ def flocked(fd):
 # This mimics the handle given by libusb1 for easy interoperability
 class SpiHandle:
   def __init__(self):
+    if not os.path.exists(DEV_PATH):
+      raise PandaSpiUnavailable(f"SPI device not found: {DEV_PATH}")
     if spidev is None:
-      raise RuntimeError("spidev is not available")
+      raise PandaSpiUnavailable("spidev is not installed")
 
     self.spi = spidev.SpiDev()  # pylint: disable=c-extension-no-member
     self.spi.open(0, 0)
@@ -82,6 +90,7 @@ class SpiHandle:
     logging.debug("starting transfer: endpoint=%d, max_rx_len=%d", endpoint, max_rx_len)
     logging.debug("==============================================")
 
+    exc = PandaSpiException()
     for n in range(MAX_XFER_RETRY_COUNT):
       logging.debug("\ntry #%d", n+1)
       try:
@@ -111,9 +120,10 @@ class SpiHandle:
           raise PandaSpiBadChecksum
 
         return dat[:-1]
-      except PandaSpiException:
-        logging.exception("SPI transfer failed, %d retries left", n)
-    raise PandaSpiTransferFailed(f"SPI transaction failed {MAX_XFER_RETRY_COUNT} times")
+      except PandaSpiException as e:
+        exc = e
+        logging.debug("SPI transfer failed, %d retries left", n, exc_info=True)
+    raise exc
 
   # libusb1 functions
   def close(self):

tests/health_test.py

@@ -1,17 +1,12 @@
 #!/usr/bin/env python3
-import os
 import time
 from panda import Panda
 
 if __name__ == "__main__":
-  spi = "SPI" in os.environ
-  print("using SPI" if spi else "using USB")
-
-
   i = 0
   pi = 0
 
-  panda = Panda(spi=spi)
+  panda = Panda()
   while True:
     st = time.monotonic()
     while time.monotonic() - st < 1: