Merge pull request #185 from arduino/can-api

Add HardwareCAN - a abstract base class for implementing CAN interfaces across Arduino cores.
arduino · Apr 26, 2023 · becd6b5 · becd6b5
2 parents 844e4bf + 032a0fc
commit becd6b5
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diff --git a/api/CanMsg.h b/api/CanMsg.h
@@ -0,0 +1,97 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef ARDUINOCORE_API_CAN_MSG_H_
+#define ARDUINOCORE_API_CAN_MSG_H_
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <cstdlib>
+#include <cstdint>
+#include <cstring>
+
+#include <Arduino.h>
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace arduino
+{
+
+/**************************************************************************************
+ * CLASS DECLARATION
+ **************************************************************************************/
+
+class CanMsg : public Printable
+{
+public:
+  static size_t constexpr MAX_DATA_LENGTH = 8;
+
+  CanMsg(uint32_t const can_id, uint8_t const can_data_len, uint8_t const * can_data_ptr)
+  : id{can_id}
+  , data_length{can_data_len}
+  , data{0}
+  {
+    memcpy(data, can_data_ptr, min(can_data_len, MAX_DATA_LENGTH));
+  }
+
+  CanMsg() : CanMsg(0, 0, nullptr) { }
+
+  CanMsg(CanMsg const & other)
+  {
+    this->id          = other.id;
+    this->data_length = other.data_length;
+    memcpy(this->data, other.data, this->data_length);
+  }
+
+  virtual ~CanMsg() { }
+
+  void operator = (CanMsg const & other)
+  {
+    if (this == &other)
+      return;
+
+    this->id          = other.id;
+    this->data_length = other.data_length;
+    memcpy(this->data, other.data, this->data_length);
+  }
+
+  virtual size_t printTo(Print & p) const override
+  {
+    char buf[20] = {0};
+    size_t len = 0;
+
+    /* Print the header. */
+    len = snprintf(buf, sizeof(buf), "[%08X] (%d) : ", id, data_length);
+    size_t n = p.write(buf, len);
+
+    /* Print the data. */
+    for (size_t d = 0; d < data_length; d++)
+    {
+      len = snprintf(buf, sizeof(buf), "%02X", data[d]);
+      n += p.write(buf, len);
+    }
+
+    /* Wrap up. */
+    return n;
+  }
+
+  uint32_t id;
+  uint8_t  data_length;
+  uint8_t  data[MAX_DATA_LENGTH];
+};
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* arduino */
+
+#endif /* ARDUINOCORE_API_CAN_MSG_H_ */
diff --git a/api/CanMsgRingbuffer.cpp b/api/CanMsgRingbuffer.cpp
@@ -0,0 +1,62 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include "CanMsgRingbuffer.h"
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace arduino
+{
+
+/**************************************************************************************
+ * CTOR/DTOR
+ **************************************************************************************/
+
+CanMsgRingbuffer::CanMsgRingbuffer()
+: _head{0}
+, _tail{0}
+, _num_elems{0}
+{
+}
+
+/**************************************************************************************
+ * PUBLIC MEMBER FUNCTIONS
+ **************************************************************************************/
+
+void CanMsgRingbuffer::enqueue(CanMsg const & msg)
+{
+  if (isFull())
+    return;
+
+  _buf[_head] = msg;
+  _head = next(_head);
+  _num_elems++;
+}
+
+CanMsg CanMsgRingbuffer::dequeue()
+{
+  if (isEmpty())
+    return CanMsg();
+
+  CanMsg const msg = _buf[_tail];
+  _tail = next(_tail);
+  _num_elems--;
+
+  return msg;
+}
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* arduino */
diff --git a/api/CanMsgRingbuffer.h b/api/CanMsgRingbuffer.h
@@ -0,0 +1,60 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef ARDUINOCORE_API_CAN_MSG_RING_BUFFER_H_
+#define ARDUINOCORE_API_CAN_MSG_RING_BUFFER_H_
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <cstdint>
+
+#include "CanMsg.h"
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace arduino
+{
+
+/**************************************************************************************
+ * CLASS DECLARATION
+ **************************************************************************************/
+
+class CanMsgRingbuffer
+{
+public:
+  static size_t constexpr RING_BUFFER_SIZE = 32U;
+
+  CanMsgRingbuffer();
+
+  inline bool isFull() const { return (_num_elems == RING_BUFFER_SIZE); }
+  void enqueue(CanMsg const & msg);
+
+  inline bool isEmpty() const { return (_num_elems == 0); }
+  CanMsg dequeue();
+
+  inline size_t available() const { return _num_elems; }
+
+private:
+  CanMsg _buf[RING_BUFFER_SIZE];
+  volatile size_t _head;
+  volatile size_t _tail;
+  volatile size_t _num_elems;
+
+  inline size_t next(size_t const idx) const { return ((idx + 1) % RING_BUFFER_SIZE); }
+};
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* arduino */
+
+#endif /* ARDUINOCORE_API_CAN_MSG_RING_BUFFER_H_ */
diff --git a/api/HardwareCAN.h b/api/HardwareCAN.h
@@ -0,0 +1,62 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef ARDUINOCORE_API_HARDWARECAN_H
+#define ARDUINOCORE_API_HARDWARECAN_H
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include "CanMsg.h"
+#include "CanMsgRingbuffer.h"
+
+/**************************************************************************************
+ * TYPEDEF
+ **************************************************************************************/
+
+enum class CanBitRate : int
+{
+  BR_125k  =  125000,
+  BR_250k  =  250000,
+  BR_500k  =  500000,
+  BR_1000k = 1000000,
+};
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace arduino
+{
+
+/**************************************************************************************
+ * CLASS DECLARATION
+ **************************************************************************************/
+
+class HardwareCAN
+{
+public:
+  virtual ~HardwareCAN() {}
+
+
+  virtual bool begin(CanBitRate const can_bitrate) = 0;
+  virtual void end() = 0;
+
+
+  virtual int write(CanMsg const &msg) = 0;
+  virtual size_t available() = 0;
+  virtual CanMsg read() = 0;
+};
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* arduino */
+
+#endif /* ARDUINOCORE_API_HARDWARECAN_H */