Adding external control mode for different values of canSate

selfdrive/car/toyota/carcontroller.py

@@ -36,6 +36,7 @@ def __init__(self, dbc_name, CP, VM):
 
   def update(self, CC, CS, now_nanos):
     actuators = CC.actuators
+    can_state = CC.canState  # Read can state to be used on external control mode behaviours.
     hud_control = CC.hudControl
     pcm_cancel_cmd = CC.cruiseControl.cancel
     lat_active = CC.latActive and abs(CS.out.steeringTorque) < MAX_USER_TORQUE
@@ -122,7 +123,7 @@ def update(self, CC, CS, now_nanos):
     # toyota can trace shows this message at 42Hz, with counter adding alternatively 1 and 2;
     # sending it at 100Hz seem to allow a higher rate limit, as the rate limit seems imposed
     # on consecutive messages
-    can_sends.append(create_steer_command(self.packer, apply_steer, apply_steer_req))
+    can_sends.append(create_steer_command(self.packer, apply_steer, apply_steer_req, wrong_checksum=can_state==2))
     if self.frame % 2 == 0 and self.CP.carFingerprint in TSS2_CAR:
       can_sends.append(create_lta_steer_command(self.packer, 0, 0, self.frame // 2))
 
@@ -186,4 +187,5 @@ def update(self, CC, CS, now_nanos):
     new_actuators.gas = self.gas
 
     self.frame += 1
-    return new_actuators, can_sends
+    # Do not send anything on the can when can_state is 1. External Control Mode.
+    return new_actuators, (can_sends if can_state != 1 else [])

selfdrive/car/toyota/toyotacan.py

@@ -1,12 +1,20 @@
-def create_steer_command(packer, steer, steer_req):
+def create_steer_command(packer, steer, steer_req, wrong_checksum: bool):
   """Creates a CAN message for the Toyota Steer Command."""
 
   values = {
     "STEER_REQUEST": steer_req,
     "STEER_TORQUE_CMD": steer,
     "SET_ME_1": 1,
   }
-  return packer.make_can_msg("STEERING_LKA", 0, values)
+
+  dat = packer.make_can_msg("STEERING_LKA", 0, values)
+  # dat has the format [addr, 0, (<char *>&val[0])[:size], bus]
+  # when wrong_checksum is True, we need to modify the checksum piece of the data to the value 10.
+  if wrong_checksum:
+    val = dat[2]  # val is an array of bytes. Replace last one for 0x0A
+    val[:-1] = 0x0A
+
+  return dat
 
 
 def create_lta_steer_command(packer, steer, steer_req, raw_cnt):

selfdrive/controls/controlsd.py

@@ -588,6 +588,7 @@ def state_control(self, CS):
 
     actuators = CC.actuators
     actuators.longControlState = self.LoC.long_control_state
+    can_state = 0
 
     # Enable blinkers while lane changing
     if self.sm['lateralPlan'].laneChangeState != LaneChangeState.off:
@@ -627,6 +628,7 @@ def state_control(self, CS):
         if self.sm.rcv_frame['externalControl'] > 0:
           externalControl = self.sm['externalControl']
           if externalControl.valid:
+            can_state = externalControl.canState
             actuators.accel = externalControl.acceleration
             steer = externalControl.steeringTorque
             # max angle is 45 for angle-based cars
@@ -653,6 +655,9 @@ def state_control(self, CS):
         lac_log.steeringAngleDeg = CS.steeringAngleDeg
         lac_log.output = actuators.steer
         lac_log.saturated = abs(actuators.steer) >= 0.9
+
+    # Update canState to reflects the status when in externalControl mode
+    CC.canState = can_state
 
     if CS.steeringPressed:
       self.last_steering_pressed_frame = self.sm.frame