/*
   * Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @defgroup  net_gnrc_netdev   Adaption layer for GNRC on top of Netdev
   * @ingroup   net_gnrc
   * @brief     Provides the glue code for @ref net_gnrc on top of @ref drivers_netdev_api
   * @{
   *
   * @file
   * @brief     netdev-GNRC glue code interface
   *
   * This interface is supposed to provide common adaption code between the
   * low-level network device interface "netdev" and the GNRC network stack.
   *
   * GNRC sends around "gnrc_pktsnip_t" structures, but netdev can only handle
   * "struct iovec" structures when sending, or a flat buffer when receiving.
   *
   * The purpose of gnrc_netdev is to bring these two interfaces together.
   *
   * @author    Kaspar Schleiser <kaspar@schleiser.de>
   */
  
  #ifndef NET_GNRC_NETDEV_H
  #define NET_GNRC_NETDEV_H
  
  #include <assert.h>
  #include <stdint.h>
  
  #include "kernel_types.h"
  #include "net/netdev.h"
  #include "net/gnrc.h"
  #include "net/gnrc/mac/types.h"
  #include "net/ieee802154.h"
  #include "net/gnrc/mac/mac.h"
  #ifdef MODULE_GNRC_MAC
  #include "net/csma_sender.h"
  #endif
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * @brief   Default priority for adaption layer's threads
   */
  #ifndef GNRC_NETDEV_MAC_PRIO
  #define GNRC_NETDEV_MAC_PRIO    (THREAD_PRIORITY_MAIN - 5)
  #endif
  
  /**
   * @brief   Type for @ref msg_t if device fired an event
   */
  #define NETDEV_MSG_TYPE_EVENT 0x1234
  
  /**
   * @brief   Mask for @ref gnrc_mac_tx_feedback_t
   */
  #define GNRC_NETDEV_MAC_INFO_TX_FEEDBACK_MASK   (0x0003U)
  
  /**
   * @brief   Flag to track if a transmission might have corrupted a received
   *          packet
   */
  #define GNRC_NETDEV_MAC_INFO_RX_STARTED         (0x0004U)
  
  /**
   * @brief   Flag to track if a device has enabled CSMA for transmissions
   *
   * If `gnrc_mac` is used, the user should be noticed that the `send()`
   * function of gnrc_netdev will be affected with the state of this flag, since
   * `gnrc_mac` accordingly adapts the `send()` function. If the device doesn't
   * support on-chip CSMA and this flag is set for requiring CSMA transmission,
   * then, the device will run software CSMA using `csma_sender` APIs.
   */
  #define GNRC_NETDEV_MAC_INFO_CSMA_ENABLED       (0x0100U)
  
  /**
   * @brief Structure holding GNRC netdev adapter state
   *
   * This structure is supposed to hold any state parameters needed
   * to use a netdev device from GNRC.
   *
   * It can be extended
   */
  typedef struct gnrc_netdev {
      /**
       * @brief Send a pktsnip using this device
       *
       * This function should convert the pktsnip into a format
       * the underlying device understands and send it.
       */
      int (*send)(struct gnrc_netdev *dev, gnrc_pktsnip_t *snip);
  
      /**
       * @brief Receive a pktsnip from this device
       *
       * This function should receive a raw frame from the underlying
       * device and convert it into a pktsnip while adding a netif header
       * and possibly marking out higher-layer headers.
       */
      gnrc_pktsnip_t * (*recv)(struct gnrc_netdev *dev);
  
      /**
       * @brief netdev handle this adapter is working with
       */
      netdev_t *dev;
  
      /**
       * @brief PID of this adapter for netapi messages
       */
      kernel_pid_t pid;
  
  #ifdef MODULE_GNRC_MAC
      /**
       * @brief general information for the MAC protocol
       */
      uint16_t mac_info;
  
      /**
       * @brief device's l2 address
       */
      uint8_t  l2_addr[IEEE802154_LONG_ADDRESS_LEN];
  
      /**
       * @brief device's l2 address length
       */
      uint8_t  l2_addr_len;
  
      /**
       * @brief device's software CSMA configuration
       */
      csma_sender_conf_t csma_conf;
  
  #if ((GNRC_MAC_RX_QUEUE_SIZE != 0) || (GNRC_MAC_DISPATCH_BUFFER_SIZE != 0)) || defined(DOXYGEN)
      /**
       * @brief MAC internal object which stores reception parameters, queues, and
       *        state machines.
       */
      gnrc_mac_rx_t rx;
  #endif /* ((GNRC_MAC_RX_QUEUE_SIZE != 0) || (GNRC_MAC_DISPATCH_BUFFER_SIZE != 0)) || defined(DOXYGEN) */
  
  #if ((GNRC_MAC_TX_QUEUE_SIZE != 0) || (GNRC_MAC_NEIGHBOR_COUNT != 0)) || defined(DOXYGEN)
      /**
       * @brief MAC internal object which stores transmission parameters, queues, and
       *        state machines.
       */
      gnrc_mac_tx_t tx;
  #endif /* ((GNRC_MAC_TX_QUEUE_SIZE != 0) || (GNRC_MAC_NEIGHBOR_COUNT == 0)) || defined(DOXYGEN) */
  
  #ifdef MODULE_GNRC_LWMAC
      /**
       * @brief LWMAC specific structure object for storing LWMAC internal states.
       */
      gnrc_lwmac_t lwmac;
  #endif
  
  #endif /* MODULE_GNRC_MAC */
  } gnrc_netdev_t;
  
  #ifdef MODULE_GNRC_MAC
  
  /**
   * @brief get the 'rx_started' state of the device
   *
   * This function checks whether the device has started receiving a packet.
   *
   * @param[in] dev  ptr to netdev device
   *
   * @return         the rx_started state
   */
  static inline bool gnrc_netdev_get_rx_started(gnrc_netdev_t *dev)
  {
      return (dev->mac_info & GNRC_NETDEV_MAC_INFO_RX_STARTED);
  }
  
  /**
   * @brief set the rx_started state of the device
   *
   * This function is intended to be called only in netdev_t::event_callback().
   *
   * @param[in] dev  ptr to netdev device
   *
   */
  static inline void gnrc_netdev_set_rx_started(gnrc_netdev_t *dev, bool rx_started)
  {
      if (rx_started) {
          dev->mac_info |= GNRC_NETDEV_MAC_INFO_RX_STARTED;
      }
      else {
          dev->mac_info &= ~GNRC_NETDEV_MAC_INFO_RX_STARTED;
      }
  }
  
  /**
   * @brief get the transmission feedback of the device
   *
   * @param[in] dev  ptr to netdev device
   *
   * @return         the transmission feedback
   */
  static inline gnrc_mac_tx_feedback_t gnrc_netdev_get_tx_feedback(gnrc_netdev_t *dev)
  {
      return (gnrc_mac_tx_feedback_t)(dev->mac_info &
                                      GNRC_NETDEV_MAC_INFO_TX_FEEDBACK_MASK);
  }
  
  /**
   * @brief set the transmission feedback of the device
   *
   * This function is intended to be called only in netdev_t::event_callback().
   *
   * @param[in] dev  ptr to netdev device
   *
   */
  static inline void gnrc_netdev_set_tx_feedback(gnrc_netdev_t *dev,
                                    gnrc_mac_tx_feedback_t txf)
  {
      /* check if gnrc_mac_tx_feedback does not collide with
       * GNRC_NETDEV_MAC_INFO_RX_STARTED */
      assert(!(txf & GNRC_NETDEV_MAC_INFO_RX_STARTED));
      /* unset previous value */
      dev->mac_info &= ~GNRC_NETDEV_MAC_INFO_TX_FEEDBACK_MASK;
      dev->mac_info |= (uint16_t)(txf & GNRC_NETDEV_MAC_INFO_TX_FEEDBACK_MASK);
  }
  #endif
  
  /**
   * @brief Initialize GNRC netdev handler thread
   *
   * @param[in] stack         ptr to preallocated stack buffer
   * @param[in] stacksize     size of stack buffer
   * @param[in] priority      priority of thread
   * @param[in] name          name of thread
   * @param[in] gnrc_netdev  ptr to netdev device to handle in created thread
   *
   * @return pid of created thread
   * @return KERNEL_PID_UNDEF on error
   */
  kernel_pid_t gnrc_netdev_init(char *stack, int stacksize, char priority,
                                 const char *name, gnrc_netdev_t *gnrc_netdev);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* NET_GNRC_NETDEV_H */
  /** @} */