text: /**
   * @file
   *
   * @brief Public APIs for the CAN drivers.
   */
  
  /*
   * Copyright (c) 2018 Alexander Wachter
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #ifndef ZEPHYR_INCLUDE_CAN_H_
  #define ZEPHYR_INCLUDE_CAN_H_
  
  /**
   * @brief CAN Interface
   * @defgroup can_interface CAN Interface
   * @ingroup io_interfaces
   * @{
   */
  
  #include <zephyr/types.h>
  #include <device.h>
  #include <string.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define CAN_EX_ID      (1 << 31)
  #define CAN_MAX_STD_ID (0x7FF)
  #define CAN_STD_ID_MASK CAN_MAX_STD_ID
  #define CAN_EXT_ID_MASK (0x1FFFFFFF)
  #define CAN_MAX_DLC    (8)
  
  /* CAN_TX_* are the error flags from tx_callback and send.*/
  /** send successfully */
  #define CAN_TX_OK       (0)
  /** general send error */
  #define CAN_TX_ERR      (1)
  /** bus arbitration lost during sending */
  #define CAN_TX_ARB_LOST (2)
  /** controller is in bus off state */
  #define CAN_TX_BUS_OFF  (3)
  /** unexpected error */
  #define CAN_TX_UNKNOWN  (4)
  
  /** attach_* failed because there is no unused filter left*/
  #define CAN_NO_FREE_FILTER (-1)
  
  /** operation timed out*/
  #define CAN_TIMEOUT (1)
  
  /**
   * @brief Statically define and initialize a can message queue.
   *
   * The message queue's ring buffer contains space for @a size messages.
   *
   * @param name Name of the message queue.
   * @param size Number of can messages.
   */
  #define CAN_DEFINE_MSGQ(name, size) K_MSGQ_DEFINE(name, sizeof(struct can_msg), size, 4)
  
  /**
   * @brief can_ide enum
   * Define if the message has a standard (11bit) or extended (29bit)
   * identifier
   */
  enum can_ide {
  	CAN_STANDARD_IDENTIFIER,
  	CAN_EXTENDED_IDENTIFIER
  };
  
  /**
   * @brief can_rtr enum
   * Define if the message is a data or remote frame
   */
  enum can_rtr {
  	CAN_DATAFRAME,
  	CAN_REMOTEREQUEST
  };
  
  /**
   * @brief can_mode enum
   * Defines the mode of the can controller
   */
  enum can_mode {
  	/*Normal mode*/
  	CAN_NORMAL_MODE,
  	/*Controller is not allowed to send dominant bits*/
  	CAN_SILENT_MODE,
  	/*Controller is in loopback mode (receive own messages)*/
  	CAN_LOOPBACK_MODE,
  	/*Combination of loopback and silent*/
  	CAN_SILENT_LOOPBACK_MODE
  };
  
  /**
   * @brief can message structure
   *
   * Used to pass can messages from userspace to the driver and
   * from driver to userspace
   *
   */
  struct can_msg {
  	/** Indicates the identifier type (standard or extended)
  	 * use can_ide enum for assignment
  	 */
  	u32_t id_type : 1;
  	/** Set the message to a transmission request instead of data frame
  	 * use can_rtr enum for assignment
  	 */
  	u32_t rtr     : 1;
  	/** Message identifier*/
  	union {
  		u32_t std_id  : 11;
  		u32_t ext_id  : 29;
  	};
  	/** The length of the message (max. 8) in byte */
  	u8_t dlc;
  	/** The message data*/
  	union {
  		u8_t data[8];
  		u32_t data_32[2];
  	};
  } __packed;
  
  /**
   * @brief can filter structure
   *
   * Used to pass can identifier filter information to the driver.
   * rtr_mask and *_id_mask are used to mask bits of the rtr and id fields.
   * If the mask bit is 0, the value of the corresponding bit in the id or rtr
   * field don't care for the filter matching.
   *
   */
  struct can_filter {
  	/** Indicates the identifier type (standard or extended)
  	 * use can_ide enum for assignment
  	 */
  	u32_t id_type      : 1;
  	/** target state of the rtr bit */
  	u32_t rtr          : 1;
  	/** target state of the identifier */
  	union {
  		u32_t std_id   : 11;
  		u32_t ext_id   : 29;
  	};
  	/** rtr bit mask */
  	u32_t rtr_mask     : 1;
  	/** identifier mask*/
  	union {
  		u32_t std_id_mask  : 11;
  		u32_t ext_id_mask  : 29;
  	};
  } __packed;
  
  /**
   * @typedef can_tx_callback_t
   * @brief Define the application callback handler function signature
   *
   * @param error_flags status of the performed send operation
   */
  typedef void (*can_tx_callback_t)(u32_t error_flags);
  
  /**
   * @typedef can_rx_callback_t
   * @brief Define the application callback handler function signature
   *        for receiving.
   *
   * @param received message
   */
  typedef void (*can_rx_callback_t)(struct can_msg *msg);
  
  /**
   * @brief Configure operation of a host controller.
   *
   * @param dev Pointer to the device structure for the driver instance.
   * @param mode Operation mode
   * @param bitrate bus-speed in Baud/s
   *
   * @retval 0 If successful.
   * @retval -EIO General input / output error, failed to configure device.
   */
  typedef int (*can_configure_t)(struct device *dev, enum can_mode mode,
  				u32_t bitrate);
  
  /**
   * @brief Perform data transfer to CAN bus.
   *
   * This routine provides a generic interface to perform data transfer
   * to the can bus. Use can_write() for simple write.
   * *
   * @param dev          Pointer to the device structure for the driver instance.
   * @param msg          Message to transfer.
   * @param timeout      Waiting for empty tx mailbox timeout in ms or K_FOREVER.
   * @param callback_isr Is called when message was sent or a transmission error
   *                     occurred. If null, this function is blocking until
   *                     message is sent.
   *
   * @retval 0 If successful.
   * @retval CAN_TX_* on failure.
   */
  typedef int (*can_send_t)(struct device *dev, struct can_msg *msg,
  			  s32_t timeout, can_tx_callback_t callback_isr);
  
  
  /**
   * @brief Attach a message queue to a single or group of identifiers.
   *
   * This routine attaches a message queue to identifiers specified by
   * a filter. Whenever the filter matches, the message is pushed to the queue
   * If a message passes more than one filter the priority of the match
   * is hardware dependent.
   * A message queue can be attached to more than one filter.
   * The message queue must me initialized before.
   * *
   * @param dev    Pointer to the device structure for the driver instance.
   * @param msgq   Pointer to the already initialized message queue.
   * @param filter Pointer to a can_filter structure defining the id filtering.
   *
   * @retval filter id on success.
   * @retval CAN_NO_FREE_FILTER if there is no filter left.
   */
  typedef int (*can_attach_msgq_t)(struct device *dev, struct k_msgq *msg_q,
  				 const struct can_filter *filter);
  
  /**
   * @brief Attach an isr callback function to a single or group of identifiers.
   *
   * This routine attaches an isr callback to identifiers specified by
   * a filter. Whenever the filter matches, the callback function is called
   * with isr context.
   * If a message passes more than one filter the priority of the match
   * is hardware dependent.
   * A callback function can be attached to more than one filter.
   * *
   * @param dev    Pointer to the device structure for the driver instance.
   * @param isr    Callback function pointer.
   * @param filter Pointer to a can_filter structure defining the id filtering.
   *
   * @retval filter id on success.
   * @retval CAN_NO_FREE_FILTER if there is no filter left.
   */
  typedef int (*can_attach_isr_t)(struct device *dev, can_rx_callback_t isr,
  				const struct can_filter *filter);
  
  /**
   * @brief Detach an isr or message queue from the identifier filtering.
   *
   * This routine detaches an isr callback  or message queue from the identifier
   * filtering.
   * *
   * @param dev       Pointer to the device structure for the driver instance.
   * @param filter_id filter id returned by can_attach_isr or can_attach_msgq.
   *
   * @retval none
   */
  typedef void (*can_detach_t)(struct device *dev, int filter_id);
  
  struct can_driver_api {
  	can_configure_t configure;
  	can_send_t send;
  	can_attach_isr_t attach_isr;
  	can_attach_msgq_t attach_msgq;
  	can_detach_t detach;
  };
  
  
  __syscall int can_send(struct device *dev, struct can_msg *msg,
  		       s32_t timeout, can_tx_callback_t callback_isr);
  
  static inline int _impl_can_send(struct device *dev, struct can_msg *msg,
  				 s32_t timeout, can_tx_callback_t callback_isr)
  {
  	const struct can_driver_api *api = dev->driver_api;
  
  	return api->send(dev, msg, timeout, callback_isr);
  }
  
  /*
   * Derived can APIs -- all implemented in terms of can_send()
   */
  
  /**
   * @brief Write a set amount of data to the can bus.
   *
   * This routine writes a set amount of data synchronously.
   *
   * @param dev  Pointer to the device structure for the driver instance.
   * @param data Data to send.
   * @param length Number of bytes to write (max. 8).
   * @param id  Identifier of the can message.
   * @param rtr Send remote transmission request or data frame
   * @param timeout Waiting for empty tx mailbox timeout in ms or K_FOREVER
   *
   * @retval 0 If successful.
   * @retval -EIO General input / output error.
   * @retval -EINVAL if length > 8.
   */
  static inline int can_write(struct device *dev, u8_t *data, u8_t length,
  			    u32_t id, enum can_rtr rtr, s32_t timeout)
  {
  	struct can_msg msg;
  
  	if (length > 8) {
  		return -EINVAL;
  	}
  
  	if (id > CAN_MAX_STD_ID) {
  		msg.id_type = CAN_EXTENDED_IDENTIFIER;
  		msg.ext_id = id & CAN_EXT_ID_MASK;
  	} else {
  		msg.id_type = CAN_STANDARD_IDENTIFIER;
  		msg.std_id = id;
  	}
  
  	msg.dlc = length;
  	msg.rtr = rtr;
  	memcpy(msg.data, data, length);
  
  	return can_send(dev, &msg, timeout, NULL);
  }
  
  
  __syscall int can_attach_msgq(struct device *dev, struct k_msgq *msg_q,
  			      const struct can_filter *filter);
  
  static inline int _impl_can_attach_msgq(struct device *dev,
  					struct k_msgq *msg_q,
  					const struct can_filter *filter)
  {
  	const struct can_driver_api *api = dev->driver_api;
  
  	return api->attach_msgq(dev, msg_q, filter);
  }
  
  
  __syscall int can_attach_isr(struct device *dev, can_rx_callback_t isr,
  			     const struct can_filter *filter);
  static inline int _impl_can_attach_isr(struct device *dev,
  				       can_rx_callback_t isr,
  				       const struct can_filter *filter)
  {
  	const struct can_driver_api *api = dev->driver_api;
  
  	return api->attach_isr(dev, isr, filter);
  }
  
  
  __syscall void can_detach(struct device *dev, int filter_id);
  
  static inline void _impl_can_detach(struct device *dev, int filter_id)
  {
  	const struct can_driver_api *api = dev->driver_api;
  
  	return api->detach(dev, filter_id);
  }
  
  
  __syscall int can_configure(struct device *dev, enum can_mode mode,
  			    u32_t bitrate);
  
  static inline int _impl_can_configure(struct device *dev, enum can_mode mode,
  				      u32_t bitrate)
  {
  	const struct can_driver_api *api = dev->driver_api;
  
  	return api->configure(dev, mode, bitrate);
  }
  
  #ifdef __cplusplus
  }
  #endif
  /**
   * @}
   */
  #include <syscalls/can.h>
  
  #endif /* ZEPHYR_INCLUDE_CAN_H_ */
  