Add GM BSM

Co-Authored-By: garrettpall <76917194+garrettpall@users.noreply.github.com>

opendbc/gm_global_a_powertrain_generated.dbc

@@ -125,6 +125,10 @@ BO_ 320 BCMTurnSignals: 3 K9_BCM
  SG_ HighBeamsActive : 7|1@0+ (1,0) [0|1] "" XXX
  SG_ HighBeamsTemporary : 5|1@0+ (1,0) [0|1] "" XXX
 
+BO_ 322 BCMBSM: 7 K9_BCM
+ SG_ Left_BSM : 6|1@0+ (1,0) [0|1] "" XXX
+ SG_ Right_BSM : 7|1@0+ (1,0) [0|1] "" XXX
+
 BO_ 328 PSCM_148: 1 K43_PSCM
 
 BO_ 381 ESPStatus: 6 K20_ECM

selfdrive/car/gm/carstate.py

@@ -35,6 +35,10 @@ class CarState(CarStateBase):
     self.pscm_status = copy.copy(pt_cp.vl["PSCMStatus"])
     self.moving_backward = pt_cp.vl["EBCMWheelSpdRear"]["MovingBackward"] != 0
 
+    if self.CP.enableBsm:
+      ret.leftBlindspot = pt_cp.vl["BCMBSM"]["Left_BSM"] == 1
+      ret.rightBlindspot = pt_cp.vl["BCMBSM"]["Right_BSM"] == 1
+
     # Variables used for avoiding LKAS faults
     self.loopback_lka_steering_cmd_updated = len(loopback_cp.vl_all["ASCMLKASteeringCmd"]["RollingCounter"]) > 0
     if self.loopback_lka_steering_cmd_updated:

selfdrive/car/gm/interface.py

@@ -21,6 +21,7 @@ BUTTONS_DICT = {CruiseButtons.RES_ACCEL: ButtonType.accelCruise, CruiseButtons.D
                 CruiseButtons.MAIN: ButtonType.altButton3, CruiseButtons.CANCEL: ButtonType.cancel}
 
 ACCELERATOR_POS_MSG = 0xbe
+BSM_MSG = 0x142
 
 NON_LINEAR_TORQUE_PARAMS = {
   CAR.BOLT_EUV: [2.6531724862969748, 1.0, 0.1919764879840985, 0.009054123646805178],
@@ -299,6 +300,9 @@ class CarInterface(CarInterfaceBase):
     if ACCELERATOR_POS_MSG not in fingerprint[CanBus.POWERTRAIN]:
       ret.flags |= GMFlags.NO_ACCELERATOR_POS_MSG.value
 
+    # Detect if BSM message is present
+    ret.enableBsm = BSM_MSG in fingerprint[CanBus.POWERTRAIN]
+
     return ret
 
   # returns a car.CarState