wpilibc/Athena/include/NetworkCommunication/CANInterfacePlugin.h

// CANInterfacePlugin.h
//
//  Defines the API for building a CAN Interface Plugin to support
//    PWM-cable-free CAN motor control on FRC robots.  This allows you
//    to connect any CAN interface to the secure Jaguar CAN driver.
//

#ifndef __CANInterfacePlugin_h__
#define __CANInterfacePlugin_h__

#include <stdint.h>

#define CAN_IS_FRAME_REMOTE 0x80000000
#define CAN_IS_FRAME_11BIT 0x40000000
#define CAN_29BIT_MESSAGE_ID_MASK 0x1FFFFFFF
#define CAN_11BIT_MESSAGE_ID_MASK 0x000007FF

class CANInterfacePlugin {
 public:
  CANInterfacePlugin() {}
  virtual ~CANInterfacePlugin() {}

  /**
   * This entry-point of the CANInterfacePlugin is passed a message that the
   * driver needs to send to
   * a device on the CAN bus.
   *
   * This function may be called from multiple contexts and must therefore be
   * reentrant.
   *
   * @param messageID The 29-bit CAN message ID in the lsbs.  The msb can
   * indicate a remote frame.
   * @param data A pointer to a buffer containing between 0 and 8 bytes to send
   * with the message.  May be nullptr if dataSize is 0.
   * @param dataSize The number of bytes to send with the message.
   * @return Return any error code.  On success return 0.
   */
  virtual int32_t sendMessage(uint32_t messageID, const uint8_t *data,
                              uint8_t dataSize) = 0;

  /**
   * This entry-point of the CANInterfacePlugin is passed buffers which should
   * be populated with
   * any received messages from devices on the CAN bus.
   *
   * This function is always called by a single task in the Jaguar driver, so it
   * need not be reentrant.
   *
   * This function is expected to block for some period of time waiting for a
   * message from the CAN bus.
   * It may timeout periodically (returning non-zero to indicate no message was
   * populated) to allow for
   * shutdown and unloading of the plugin.
   *
   * @param messageID A reference to be populated with a received 29-bit CAN
   * message ID in the lsbs.
   * @param data A pointer to a buffer of 8 bytes to be populated with data
   * received with the message.
   * @param dataSize A reference to be populated with the size of the data
   * received (0 - 8 bytes).
   * @return This should return 0 if a message was populated, non-0 if no
   * message was not populated.
   */
  virtual int32_t receiveMessage(uint32_t &messageID, uint8_t *data,
                                 uint8_t &dataSize) = 0;

#if defined(__linux)
  /**
   * This entry-point of the CANInterfacePlugin returns status of the CAN bus.
   *
   * This function may be called from multiple contexts and must therefore be
   * reentrant.
   *
   * This function will return detailed hardware status if available for
   * diagnostics of the CAN interface.
   *
   * @param busOffCount The number of times that sendMessage failed with a
   * busOff error indicating that messages
   *  are not successfully transmitted on the bus.
   * @param txFullCount The number of times that sendMessage failed with a
   * txFifoFull error indicating that messages
   *  are not successfully received by any CAN device.
   * @param receiveErrorCount The count of receive errors as reported by the CAN
   * driver.
   * @param transmitErrorCount The count of transmit errors as reported by the
   * CAN driver.
   * @return This should return 0 if all status was retrieved successfully or an
   * error code if not.
   */
  virtual int32_t getStatus(uint32_t &busOffCount, uint32_t &txFullCount,
                            uint32_t &receiveErrorCount,
                            uint32_t &transmitErrorCount) {
    return 0;
  }
#endif
};

/**
 * This function allows you to register a CANInterfacePlugin to provide access a
 * CAN bus.
 *
 * @param interface A pointer to an object that inherits from CANInterfacePlugin
 * and implements
 * the pure virtual interface.  If nullptr, unregister the current plugin.
 */
void FRC_NetworkCommunication_CANSessionMux_registerInterface(
    CANInterfacePlugin *interface);

#endif  // __CANInterfacePlugin_h__