STM32 CAN Error Handling (#644)

* Add ioctl() for getting the CAN state.

* Properly handle bus error/off states.

* Change execution priority.

* Support Arduino.

* Add SCE interrupt handler call to Common CAN IRQ handler for Arduino.

* Reverse error handling order and make clearing the flags non-exclusive.

* Fix review comments.

src/freertos_drivers/st/Stm32Can.cxx

@@ -37,6 +37,8 @@
 
 #include <stdint.h>
 
+#include "can_ioctl.h"
+
 #include "stm32f_hal_conf.hxx"
 
 #if defined (STM32F072xB) || defined (STM32F091xC)
@@ -53,6 +55,7 @@
 #define CAN_TX_IRQN USB_HP_CAN1_TX_IRQn
 #define CAN_IRQN CAN_TX_IRQN
 #define CAN_SECOND_IRQN USB_LP_CAN1_RX0_IRQn
+#define CAN_THIRD_IRQN CAN1_SCE_IRQn
 #define CAN CAN1
 #define CAN_CLOCK (cm3_cpu_clock_hz >> 1)
 
@@ -63,6 +66,7 @@
 #define CAN_TX_IRQN USB_HP_CAN_TX_IRQn
 #define CAN_IRQN CAN_TX_IRQN
 #define CAN_SECOND_IRQN USB_LP_CAN_RX0_IRQn
+#define CAN_THIRD_IRQN CAN1_SCE_IRQn
 #define CAN_CLOCK (cm3_cpu_clock_hz >> 1)
 
 #elif defined (STM32L431xx) || defined (STM32L432xx)
@@ -72,6 +76,7 @@
 #define CAN_TX_IRQN CAN1_TX_IRQn
 #define CAN_IRQN CAN_TX_IRQN
 #define CAN_SECOND_IRQN CAN1_RX0_IRQn
+#define CAN_THIRD_IRQN CAN1_SCE_IRQn
 #define CAN_CLOCK (cm3_cpu_clock_hz)
 
 #elif defined (STM32F767xx)
@@ -82,6 +87,7 @@
 #define CAN_TX_IRQN CAN1_TX_IRQn
 #define CAN_IRQN CAN_TX_IRQN
 #define CAN_SECOND_IRQN CAN1_RX0_IRQn
+#define CAN_THIRD_IRQN CAN1_SCE_IRQn
 #define CAN_CLOCK (cm3_cpu_clock_hz >> 2) // 54 MHz, sysclk/4
 
 #else
@@ -95,6 +101,7 @@ Stm32Can *Stm32Can::instances[1] = {NULL};
  */
 Stm32Can::Stm32Can(const char *name)
     : Can(name)
+    , state_(CAN_STATE_STOPPED)
 {
     /* only one instance allowed */
     HASSERT(instances[0] == NULL);
@@ -119,10 +126,25 @@ Stm32Can::Stm32Can(const char *name)
 #ifdef SPLIT_INT
     HAL_NVIC_DisableIRQ(CAN_SECOND_IRQN);
     SetInterruptPriority(CAN_SECOND_IRQN, configKERNEL_INTERRUPT_PRIORITY);
+    HAL_NVIC_DisableIRQ(CAN_THIRD_IRQN);
+    SetInterruptPriority(CAN_THIRD_IRQN, configKERNEL_INTERRUPT_PRIORITY);
 #endif
 #endif
 }
 
+//
+// Stm32Can::ioctl()
+//
+int Stm32Can::ioctl(File *file, unsigned long int key, unsigned long data)
+{
+    if (key == SIOCGCANSTATE)
+    {
+        *((can_state_t*)data) = state_;
+        return 0;
+    }
+    return -EINVAL;
+}
+
 /** Enable use of the device.
  */
 void Stm32Can::enable()
@@ -162,11 +184,15 @@ void Stm32Can::enable()
     CAN->FA1R = 0x000000001;
     CAN->FMR &= ~CAN_FMR_FINIT;
 
+    state_ = CAN_STATE_ACTIVE;
+
     /* enable interrupts */
-    CAN->IER = (/*CAN_IER_ERRIE |*/ CAN_IER_BOFIE | CAN_IER_FMPIE0);
+    CAN->IER = (CAN_IER_BOFIE | CAN_IER_EPVIE | CAN_IER_EWGIE); // errors
+    CAN->IER |= (CAN_IER_ERRIE | CAN_IER_FMPIE0); // error + receive
     HAL_NVIC_EnableIRQ(CAN_IRQN);
 #ifdef SPLIT_INT
     HAL_NVIC_EnableIRQ(CAN_SECOND_IRQN);
+    HAL_NVIC_EnableIRQ(CAN_THIRD_IRQN);
 #endif
 }
 
@@ -177,9 +203,12 @@ void Stm32Can::disable()
     HAL_NVIC_DisableIRQ(CAN_IRQN);
 #ifdef SPLIT_INT
     HAL_NVIC_DisableIRQ(CAN_SECOND_IRQN);
+    HAL_NVIC_DisableIRQ(CAN_THIRD_IRQN);
 #endif
     CAN->IER = 0;
 
+    state_ = CAN_STATE_STOPPED;
+
     /* disable sleep, enter init mode */
     CAN->MCR = CAN_MCR_INRQ;
 }
@@ -261,30 +290,6 @@ void Stm32Can::rx_interrupt_handler()
 {
     unsigned msg_receive_count = 0;
 
-    if (CAN->ESR & CAN_ESR_BOFF)
-    {
-        /* bus off error condition */
-        CAN->TSR |= CAN_TSR_ABRQ2;
-        CAN->TSR |= CAN_TSR_ABRQ1;
-        CAN->TSR |= CAN_TSR_ABRQ0;
-        CAN->IER &= ~CAN_IER_TMEIE;
-        txBuf->flush();
-        txBuf->signal_condition_from_isr();
-    }
-#if 0
-    if (CAN->MSR & CAN_MSR_ERRI)
-    {
-        /* error condition */
-        CAN->TSR |= CAN_TSR_ABRQ2;
-        CAN->TSR |= CAN_TSR_ABRQ1;
-        CAN->TSR |= CAN_TSR_ABRQ0;
-        CAN->IER &= ~CAN_IER_TMEIE;
-        CAN->MSR &= ~CAN_MSR_ERRI;
-        txBuf->flush();
-        txBuf->signal_condition_from_isr();
-        ++softErrorCount;
-    }
-#endif
     while (CAN->RF0R & CAN_RF0R_FMP0)
     {
         /* rx data received */
@@ -339,6 +344,7 @@ void Stm32Can::rx_interrupt_handler()
         /* advance the "zero copy" buffer by the number of messages received */
         rxBuf->advance(msg_receive_count);
         rxBuf->signal_condition_from_isr();
+        state_ = CAN_STATE_ACTIVE;
     }
 }
 
@@ -413,9 +419,48 @@ void Stm32Can::tx_interrupt_handler()
             CAN->IER &= ~CAN_IER_TMEIE;
         }
         txBuf->signal_condition_from_isr();
+        state_ = CAN_STATE_ACTIVE;
     }
 }
 
+/*
+ * Stm32Can::sce_interrupt_handler()
+ */
+void Stm32Can::sce_interrupt_handler()
+{
+    if (CAN->MSR & CAN_MSR_ERRI)
+    {
+        /* error interrupt has occured */
+        CAN->MSR |= CAN_MSR_ERRI; // clear flag
+
+        if (CAN->ESR & CAN_ESR_EWGF)
+        {
+            /* error warning condition */
+            state_ = CAN_STATE_BUS_WARNING;
+            CAN->ESR &= ~CAN_ESR_EWGF;
+        }
+        if (CAN->ESR & CAN_ESR_EPVF)
+        {
+            /* error passive condition */
+            ++softErrorCount;
+            state_ = CAN_STATE_BUS_PASSIVE;
+            CAN->ESR &= ~CAN_ESR_EPVF;
+        }
+        if (CAN->ESR & CAN_ESR_BOFF)
+        {
+            /* bus off error condition */
+            CAN->TSR |= CAN_TSR_ABRQ2;
+            CAN->TSR |= CAN_TSR_ABRQ1;
+            CAN->TSR |= CAN_TSR_ABRQ0;
+            CAN->IER &= ~CAN_IER_TMEIE;
+            txBuf->flush();
+            txBuf->signal_condition_from_isr();
+            ++busOffCount;
+            state_ = CAN_STATE_BUS_OFF;
+            CAN->ESR &= ~CAN_ESR_BOFF;
+        }
+    }
+}
 
 extern "C" {
 /** This is the interrupt handler for the can device.
@@ -426,6 +471,7 @@ void cec_can_interrupt_handler(void)
 {
     Stm32Can::instances[0]->rx_interrupt_handler();
     Stm32Can::instances[0]->tx_interrupt_handler();
+    Stm32Can::instances[0]->sce_interrupt_handler();
 }
 #elif defined (STM32F103xB) || defined (STM32F303xC) || defined (STM32F303xE)
 
@@ -439,6 +485,11 @@ void usb_lp_can1_rx0_interrupt_handler(void)
     Stm32Can::instances[0]->rx_interrupt_handler();
 }
 
+void can1_sce_interrupt_handler(void)
+{
+    Stm32Can::instances[0]->sce_interrupt_handler();
+}
+
 #elif defined(STM32F767xx) || defined(STM32L431xx) || defined(STM32L432xx)
 
 void can1_tx_interrupt_handler(void)
@@ -451,6 +502,11 @@ void can1_rx0_interrupt_handler(void)
     Stm32Can::instances[0]->rx_interrupt_handler();
 }
 
+void can1_sce_interrupt_handler(void)
+{
+    Stm32Can::instances[0]->sce_interrupt_handler();
+}
+
 #else
 #error Dont know what STM32 chip you have.
 #endif
@@ -515,6 +571,7 @@ void CEC_CAN_IRQHandler(void)
 {
     Stm32Can::instances[0]->rx_interrupt_handler();
     Stm32Can::instances[0]->tx_interrupt_handler();
+    Stm32Can::instances[0]->sce_interrupt_handler();
 }
 void CAN1_TX_IRQHandler(void)
 {
@@ -524,6 +581,10 @@ void CAN1_RX0_IRQHandler(void)
 {
     Stm32Can::instances[0]->rx_interrupt_handler();
 }
+void CAN1_SCE_IRQHandler(void)
+{
+    Stm32Can::instances[0]->sce_interrupt_handler();
+}
 } // extern "C"
 
 #endif

src/freertos_drivers/st/Stm32Can.hxx

@@ -65,11 +65,20 @@ public:
     void rx_interrupt_handler();
     /** Handle an interrupt. */
     void tx_interrupt_handler();
+    /** Handle an interrupt. */
+    void sce_interrupt_handler();
 
     /** Instance pointers help us get context from the interrupt handler(s) */
     static Stm32Can *instances[1];
 
 private:
+    /// Request an ioctl transaction.
+    /// @param file file reference for this device
+    /// @param key ioctl key
+    /// @param data key data
+    /// @return >= 0 upon success, -errno upon failure
+    int ioctl(File *file, unsigned long int key, unsigned long data) override;
+
     void enable() override; /**< function to enable device */
     void disable() override; /**< function to disable device */
     void tx_msg() override; /**< function to try and transmit a message */
@@ -79,6 +88,8 @@ private:
      */
     static unsigned int intCount;
 
+    uint8_t state_; ///< present bus state
+
     /** Default constructor.
      */
     Stm32Can();