Fixed bus off handling and other bugs in SAME70 CAN driver3.2RC2

Also allow temperatures below -5C to be read by low-resistance
thermistors

4 files changed, 48 insertions, 43 deletions

diff --git a/src/CAN/CanInterface.cpp b/src/CAN/CanInterface.cpp
index bb608952..02818e52 100644
--- a/src/CAN/CanInterface.cpp
+++ b/src/CAN/CanInterface.cpp
@@ -181,7 +181,7 @@ static void configure_mcan() noexcept
 {
 	mcan_config config_mcan;
 	mcan_get_config_defaults(&config_mcan);
-	mcan_init(&mcan_instance, MCAN_MODULE, &config_mcan);
+	mcan_init(&mcan_instance, &config_mcan);
 	mcan_enable_fd_mode(&mcan_instance);
 
 	mcan_extended_message_filter_element et_filter;
@@ -210,7 +210,9 @@ static void configure_mcan() noexcept
 	et_filter.F1.bit.EFT = 2;
 	mcan_set_rx_extended_filter(&mcan_instance, &et_filter, 2);
 
-	mcan_enable_interrupt(&mcan_instance, (mcan_interrupt_source)(MCAN_FORMAT_ERROR | MCAN_ACKNOWLEDGE_ERROR | MCAN_BUS_OFF | MCAN_RX_FIFO_0_NEW_MESSAGE | MCAN_RX_FIFO_1_NEW_MESSAGE | MCAN_RX_FIFO_0_FULL | MCAN_RX_FIFO_1_FULL));
+	mcan_enable_interrupt(&mcan_instance, (mcan_interrupt_source)(MCAN_FORMAT_ERROR | MCAN_ACKNOWLEDGE_ERROR | MCAN_BUS_OFF
+																		| MCAN_RX_FIFO_0_NEW_MESSAGE | MCAN_RX_FIFO_1_NEW_MESSAGE
+																		| MCAN_RX_FIFO_0_LOST_MESSAGE | MCAN_RX_FIFO_1_MESSAGE_LOST));
 	NVIC_ClearPendingIRQ(MCanIRQn);
 	NVIC_EnableIRQ(MCanIRQn);
 
@@ -249,15 +251,20 @@ extern "C" void MCAN_INT0_Handler() noexcept
 #endif
 	}
 
-	if (status & MCAN_RX_FIFO_0_NEW_MESSAGE)
+	if (status & (MCAN_RX_FIFO_0_LOST_MESSAGE | MCAN_RX_FIFO_1_MESSAGE_LOST))
 	{
-		mcan_clear_interrupt_status(&mcan_instance, MCAN_RX_FIFO_0_NEW_MESSAGE);
+		++messagesLost;
+	}
+
+	if (status & (MCAN_RX_FIFO_0_NEW_MESSAGE | MCAN_RX_FIFO_0_LOST_MESSAGE))
+	{
+		mcan_clear_interrupt_status(&mcan_instance, (mcan_interrupt_source)(MCAN_RX_FIFO_0_NEW_MESSAGE | MCAN_RX_FIFO_0_LOST_MESSAGE));
 		TaskBase::GiveFromISR(mcan_instance.taskWaitingOnFifo[0]);
 	}
 
-	if (status & MCAN_RX_FIFO_1_NEW_MESSAGE)
+	if (status & (MCAN_RX_FIFO_1_NEW_MESSAGE | MCAN_RX_FIFO_1_MESSAGE_LOST))
 	{
-		mcan_clear_interrupt_status(&mcan_instance, MCAN_RX_FIFO_1_NEW_MESSAGE);
+		mcan_clear_interrupt_status(&mcan_instance, (mcan_interrupt_source)(MCAN_RX_FIFO_1_NEW_MESSAGE | MCAN_RX_FIFO_1_MESSAGE_LOST));
 		TaskBase::GiveFromISR(mcan_instance.taskWaitingOnFifo[1]);
 	}
 
@@ -271,12 +278,6 @@ extern "C" void MCAN_INT0_Handler() noexcept
 		mcan_clear_interrupt_status(&mcan_instance, (mcan_interrupt_source)(MCAN_FORMAT_ERROR));
 	}
 
-	if (status & (MCAN_RX_FIFO_0_FULL | MCAN_RX_FIFO_1_FULL))
-	{
-		mcan_clear_interrupt_status(&mcan_instance, (mcan_interrupt_source)(MCAN_RX_FIFO_0_FULL | MCAN_RX_FIFO_1_FULL));
-		++messagesLost;
-	}
-
 	if (status & MCAN_BUS_OFF)
 	{
 		mcan_clear_interrupt_status(&mcan_instance, MCAN_BUS_OFF);
@@ -350,6 +351,7 @@ void CanInterface::Init() noexcept
 										(CanId::BoardAddressMask << CanId::DstAddressShift) | CanId::ResponseBit);
 	can0dev->Enable();
 #else
+	mcan_init_once(&mcan_instance, MCAN_MODULE);
 	configure_mcan();
 #endif
 
@@ -782,26 +784,25 @@ void CanInterface::SendMessageNoReplyNoFree(CanMessageBuffer *buf) noexcept
 // The CanReceiver task
 extern "C" [[noreturn]] void CanReceiverLoop(void *) noexcept
 {
-	CanMessageBuffer *buf;
-	while ((buf = CanMessageBuffer::Allocate()) == nullptr)
-	{
-		delay(2);
-	}
-
+	CanMessageBuffer buf(nullptr);
 	for (;;)
 	{
 #if USE_NEW_CAN_DRIVER
-		can0dev->ReceiveMessage(RxBufferIndexRequest, TaskBase::TimeoutUnlimited, buf);
+		if (can0dev->ReceiveMessage(RxBufferIndexRequest, TaskBase::TimeoutUnlimited, &buf))
 #else
-		GetMessageFromFifo(&mcan_instance, buf, RxFifoIndexRequest, TaskBase::TimeoutUnlimited);
-		++messagesReceived;
+		if (GetMessageFromFifo(&mcan_instance, &buf, RxFifoIndexRequest, TaskBase::TimeoutUnlimited))
 #endif
-		if (reprap.Debug(moduleCan))
 		{
-			buf->DebugPrint("Rx0:");
-		}
+#if !USE_NEW_CAN_DRIVER
+			++messagesReceived;
+#endif
+			if (reprap.Debug(moduleCan))
+			{
+				buf.DebugPrint("Rx0:");
+			}
 
-		CommandProcessor::ProcessReceivedMessage(buf);
+			CommandProcessor::ProcessReceivedMessage(&buf);
+		}
 	}
 }
 
diff --git a/src/Hardware/SAME70/CanDriver.cpp b/src/Hardware/SAME70/CanDriver.cpp
index 761f759a..e519e4be 100644
--- a/src/Hardware/SAME70/CanDriver.cpp
+++ b/src/Hardware/SAME70/CanDriver.cpp
@@ -301,20 +301,9 @@ static void _mcan_enable_peripheral_clock(mcan_module *const module_inst) noexce
 	}
 }
 
-/**
- * \brief initialize can module.
- *
- * \param module_inst  MCAN instance
- * \param hw  Base address of MCAN.
- * \param config default configuration .
- */
-void mcan_init(mcan_module *const module_inst, Mcan *hw, struct mcan_config *config) noexcept
+// One-time initialisation. Do not call this to reset after a bus_off condition.
+void mcan_init_once(mcan_module *const module_inst, Mcan *hw) noexcept
 {
-	/* Sanity check arguments */
-	Assert(module_inst);
-	Assert(hw);
-	Assert(config);
-
 	/* Associate the software module instance with the hardware module */
 	module_inst->hw = hw;
 	module_inst->taskWaitingOnFifo[0] = module_inst->taskWaitingOnFifo[1] = nullptr;
@@ -327,6 +316,18 @@ void mcan_init(mcan_module *const module_inst, Mcan *hw, struct mcan_config *con
 
 	/* Enable peripheral clock */
 	_mcan_enable_peripheral_clock(module_inst);
+}
+
+/**
+ * \brief initialize can module.
+ *
+ * \param module_inst  MCAN instance
+ * \param hw  Base address of MCAN.
+ * \param config default configuration .
+ */
+void mcan_init(mcan_module *const module_inst, struct mcan_config *config) noexcept
+{
+	Mcan * const hw = module_inst->hw;
 
 	/* Configuration Change Enable. */
 	hw->MCAN_CCCR |= MCAN_CCCR_CCE;
@@ -750,11 +751,11 @@ bool GetMessageFromFifo(mcan_module *const module_inst, CanMessageBuffer *buf, u
 			mcan_rx_element elem;
 			if (fifoNumber == 1)
 			{
-				mcan_get_rx_fifo_1_element(module_inst, &elem, getIndex);		// copy the data (TODO use our own driver, avoid double copying)
+				mcan_get_rx_fifo_1_element(module_inst, &elem, getIndex);			// copy the data (TODO use our own driver, avoid double copying)
 			}
 			else
 			{
-				mcan_get_rx_fifo_0_element(module_inst, &elem, getIndex);		// copy the data (TODO use our own driver, avoid double copying)
+				mcan_get_rx_fifo_0_element(module_inst, &elem, getIndex);			// copy the data (TODO use our own driver, avoid double copying)
 			}
 			fifoRegisters[1] = getIndex;											// acknowledge it, release the FIFO entry
 
diff --git a/src/Hardware/SAME70/CanDriver.h b/src/Hardware/SAME70/CanDriver.h
index bd505233..20b20b27 100644
--- a/src/Hardware/SAME70/CanDriver.h
+++ b/src/Hardware/SAME70/CanDriver.h
@@ -534,7 +534,7 @@ enum mcan_nonmatching_frames_action {
 struct mcan_module
 {
 	Mcan *hw;
-	TaskHandle taskWaitingOnFifo[2];
+	volatile TaskHandle taskWaitingOnFifo[2];
 };
 
 /**
@@ -674,7 +674,8 @@ static inline void mcan_get_config_defaults(struct mcan_config *const config) no
 	config->tx_event_fifo_watermark = 0;
 }
 
-void mcan_init(mcan_module *const module_inst, Mcan *hw, mcan_config *config) noexcept;
+void mcan_init_once(mcan_module *const module_inst, Mcan *hw) noexcept;
+void mcan_init(mcan_module *const module_inst, mcan_config *config) noexcept;
 void mcan_start(mcan_module *const module_inst) noexcept;
 void mcan_stop(mcan_module *const module_inst) noexcept;
 void mcan_enable_fd_mode(mcan_module *const module_inst) noexcept;
diff --git a/src/Heating/Sensors/Thermistor.cpp b/src/Heating/Sensors/Thermistor.cpp
index 4fa8e1e0..873e4325 100644
--- a/src/Heating/Sensors/Thermistor.cpp
+++ b/src/Heating/Sensors/Thermistor.cpp
@@ -324,7 +324,9 @@ void Thermistor::Poll() noexcept
 					const float recipT = shA + shB * logResistance + shC * logResistance * logResistance * logResistance;
 					const float temp =  (recipT > 0.0) ? (1.0/recipT) + ABS_ZERO : BadErrorTemperature;
 
-					if (temp < MinimumConnectedTemperature)
+					// It's hard to distinguish between an open circuit and a cold high-resistance thermistor.
+					// So we treat a temperature below -5C as an open circuit, unless we are using a low-resistance thermistor. The E3D thermistor has a resistance of about 470k @ -5C.
+					if (temp < MinimumConnectedTemperature && resistance > seriesR * 100)
 					{
 						// Assume thermistor is disconnected
 						SetResult(ABS_ZERO, TemperatureError::openCircuit);