VW MQB: Redundant brake pressed signals (commaai#1137)

* VW MQB: Redundant brake pressed signals

* bump timer for safety tests in CI

* use nicer f-string syntax

* don't need that

board/safety/safety_volkswagen_mqb.h

@@ -27,6 +27,7 @@ const int VOLKSWAGEN_MQB_MIN_ACCEL = -3500;
 #define MSG_GRA_ACC_01  0x12B   // TX by OP, ACC control buttons for cancel/resume
 #define MSG_ACC_07      0x12E   // TX by OP, ACC control instructions to the drivetrain coordinator
 #define MSG_ACC_02      0x30C   // TX by OP, ACC HUD data to the instrument cluster
+#define MSG_MOTOR_14    0x3BE   // RX from ECU, for brake switch status
 #define MSG_LDW_02      0x397   // TX by OP, Lane line recognition and text alerts
 
 // Transmit of GRA_ACC_01 is allowed on bus 0 and 2 to keep compatibility with gateway and camera integration
@@ -35,16 +36,19 @@ const CanMsg VOLKSWAGEN_MQB_LONG_TX_MSGS[] = {{MSG_HCA_01, 0, 8}, {MSG_LDW_02, 0
                                               {MSG_ACC_02, 0, 8}, {MSG_ACC_06, 0, 8}, {MSG_ACC_07, 0, 8}};
 
 AddrCheckStruct volkswagen_mqb_addr_checks[] = {
-  {.msg = {{MSG_ESP_19, 0, 8, .check_checksum = false, .max_counter = 0U,  .expected_timestep = 10000U}, { 0 }, { 0 }}},
-  {.msg = {{MSG_LH_EPS_03, 0, 8, .check_checksum = true,  .max_counter = 15U, .expected_timestep = 10000U}, { 0 }, { 0 }}},
-  {.msg = {{MSG_ESP_05, 0, 8, .check_checksum = true,  .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
-  {.msg = {{MSG_TSK_06, 0, 8, .check_checksum = true,  .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
-  {.msg = {{MSG_MOTOR_20, 0, 8, .check_checksum = true,  .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_ESP_19, 0, 8, .check_checksum = false, .max_counter = 0U, .expected_timestep = 10000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_LH_EPS_03, 0, 8, .check_checksum = true, .max_counter = 15U, .expected_timestep = 10000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_ESP_05, 0, 8, .check_checksum = true, .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_TSK_06, 0, 8, .check_checksum = true, .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_MOTOR_20, 0, 8, .check_checksum = true, .max_counter = 15U, .expected_timestep = 20000U}, { 0 }, { 0 }}},
+  {.msg = {{MSG_MOTOR_14, 0, 8, .check_checksum = false, .max_counter = 0U, .expected_timestep = 100000U}, { 0 }, { 0 }}},
 };
 #define VOLKSWAGEN_MQB_ADDR_CHECKS_LEN (sizeof(volkswagen_mqb_addr_checks) / sizeof(volkswagen_mqb_addr_checks[0]))
 addr_checks volkswagen_mqb_rx_checks = {volkswagen_mqb_addr_checks, VOLKSWAGEN_MQB_ADDR_CHECKS_LEN};
 
 uint8_t volkswagen_crc8_lut_8h2f[256]; // Static lookup table for CRC8 poly 0x2F, aka 8H2F/AUTOSAR
+bool volkswagen_mqb_brake_pedal_switch = false;
+bool volkswagen_mqb_brake_pressure_detected = false;
 
 static uint32_t volkswagen_mqb_get_checksum(CANPacket_t *to_push) {
   return (uint8_t)GET_BYTE(to_push, 0);
@@ -95,6 +99,8 @@ static const addr_checks* volkswagen_mqb_init(uint16_t param) {
 
   volkswagen_set_button_prev = false;
   volkswagen_resume_button_prev = false;
+  volkswagen_mqb_brake_pedal_switch = false;
+  volkswagen_mqb_brake_pressure_detected = false;
 
 #ifdef ALLOW_DEBUG
   volkswagen_longitudinal = GET_FLAG(param, FLAG_VOLKSWAGEN_LONG_CONTROL);
@@ -176,11 +182,18 @@ static int volkswagen_mqb_rx_hook(CANPacket_t *to_push) {
       gas_pressed = ((GET_BYTES_04(to_push) >> 12) & 0xFFU) != 0U;
     }
 
-    // Signal: ESP_05.ESP_Fahrer_bremst
+    // Signal: Motor_14.MO_Fahrer_bremst (ECU detected brake pedal switch F63)
+    if (addr == MSG_MOTOR_14) {
+      volkswagen_mqb_brake_pedal_switch = (GET_BYTE(to_push, 3) & 0x10U) >> 4;
+    }
+
+    // Signal: ESP_05.ESP_Fahrer_bremst (ESP detected driver brake pressure above platform specified threshold)
     if (addr == MSG_ESP_05) {
-      brake_pressed = (GET_BYTE(to_push, 3) & 0x4U) >> 2;
+      volkswagen_mqb_brake_pressure_detected = (GET_BYTE(to_push, 3) & 0x4U) >> 2;
     }
 
+    brake_pressed = volkswagen_mqb_brake_pedal_switch || volkswagen_mqb_brake_pressure_detected;
+
     generic_rx_checks((addr == MSG_HCA_01));
   }
   return valid;

tests/safety/test_volkswagen_mqb.py

@@ -48,11 +48,19 @@ def _speed_msg(self, speed):
     values = {"ESP_%s_Radgeschw_02" % s: speed for s in ["HL", "HR", "VL", "VR"]}
     return self.packer.make_can_msg_panda("ESP_19", 0, values)
 
-  # Brake light switch _esp_05_msg
-  def _user_brake_msg(self, brake):
+  # Driver brake pressure over threshold
+  def _esp_05_msg(self, brake):
     values = {"ESP_Fahrer_bremst": brake}
     return self.packer.make_can_msg_panda("ESP_05", 0, values)
 
+  # Brake pedal switch
+  def _motor_14_msg(self, brake):
+    values = {"MO_Fahrer_bremst": brake}
+    return self.packer.make_can_msg_panda("Motor_14", 0, values)
+
+  def _user_brake_msg(self, brake):
+    return self._motor_14_msg(brake)
+
   # Driver throttle input
   def _user_gas_msg(self, gas):
     values = {"MO_Fahrpedalrohwert_01": gas}
@@ -95,6 +103,18 @@ def _acc_07_msg(self, accel, secondary_accel=3.02):
     values = {"ACC_Sollbeschleunigung_02": accel, "ACC_Folgebeschl": secondary_accel}
     return self.packer.make_can_msg_panda("ACC_07", 0, values)
 
+  # Verify brake_pressed is true if either the switch or pressure threshold signals are true
+  def test_redundant_brake_signals(self):
+    test_combinations = [(True, True, True), (True, True, False), (True, False, True), (False, False, False)]
+    for brake_pressed, motor_14_signal, esp_05_signal in test_combinations:
+      self._rx(self._motor_14_msg(False))
+      self._rx(self._esp_05_msg(False))
+      self.assertFalse(self.safety.get_brake_pressed_prev())
+      self._rx(self._motor_14_msg(motor_14_signal))
+      self._rx(self._esp_05_msg(esp_05_signal))
+      self.assertEqual(brake_pressed, self.safety.get_brake_pressed_prev(),
+                       f"expected {brake_pressed=} with {motor_14_signal=} and {esp_05_signal=}")
+
   def test_torque_measurements(self):
     # TODO: make this test work with all cars
     self._rx(self._torque_driver_msg(50))