/*
 * Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
 *               2015 Ell-i open source co-operative
 *               2015 Freie Universität Berlin
 *               2014 Martine Lenders <mlenders@inf.fu-berlin.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    drivers_netdev_netdev2 Generic Low-Level Network Driver Interface v2
 * @ingroup     drivers_netdev
 * @brief       This is the second version of a generic low-level network
 *              driver interface
 * @{
 *
 * This interface is supposed to be a low-level interface for network drivers.
 *
 * Example call flow:
 *
 * 1. packet arrives -> driver calls netdev2->event_callback with
 *    event==NETDEV_EVENT_ISR (from interrupt routine)
 * 2. event_callback wakes up upper layer thread
 * 3. upper layer calls netdev2->driver.isr()
 * 4. netdev2->driver.isr() calls netdev2->event_callback() with
 *    event==NETDEV_EVENT_RX_COMPLETE
 * 5. netdev2->event_callback() uses netdev2->driver.recv() to fetch packet
 *
 * @file
 * @brief       Definitions low-level network driver interface
 *
 * @author      Kaspar Schleiser <kaspar@schleiser.de>
 * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
 * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
 */

#ifndef NETDEV2_H
#define NETDEV2_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <sys/uio.h>

#include "net/netopt.h"

enum {
    NETDEV2_TYPE_UNKNOWN,
    NETDEV2_TYPE_RAW,
    NETDEV2_TYPE_ETHERNET,
    NETDEV2_TYPE_802154,
    NETDEV2_TYPE_CC110X,
};

/**
 * @brief   Possible event types that are send from the device driver to the
 *          upper layer
 */
typedef enum {
    NETDEV2_EVENT_ISR,           /**< driver needs it's ISR handled */
    NETDEV2_EVENT_RX_STARTED,    /**< started to receive a packet */
    NETDEV2_EVENT_RX_COMPLETE,   /**< finished receiving a packet */
    NETDEV2_EVENT_TX_STARTED,    /**< started to transfer a packet */
    NETDEV2_EVENT_TX_COMPLETE,   /**< finished transferring packet */
    NETDEV2_EVENT_LINK_UP,       /**< link established */
    NETDEV2_EVENT_LINK_DOWN,     /**< link gone */
    /* expand this list if needed */
} netdev2_event_t;

/**
 * @brief   Forward declaration for netdev2 struct
 */
typedef struct netdev2 netdev2_t;

/**
 * @brief   Event callback for signaling event to upper layers
 *
 * @param[in] type          type of the event
 * @param[in] arg           event argument
 */
typedef void (*netdev2_event_cb_t)(netdev2_t *dev, netdev2_event_t event, void* arg);

/**
 * @brief Structure to hold driver state
 *
 * Supposed to be extended by driver implementations.
 * The extended structure should contain all variable driver state.
 */
struct netdev2 {
    const struct netdev2_driver *driver;    /**< ptr to that driver's interface. */
    netdev2_event_cb_t event_callback;      /**< callback for device events */
    void* isr_arg;                          /**< argument to pass on isr event */
};

/**
 * @brief Structure to hold driver interface -> function mapping
 *
 * The send/receive functions expect/return a full ethernet
 * frame (dst mac, src mac, ethertype, payload, no checksum).
 */
typedef struct netdev2_driver {
    /**
     * @brief Send frame
     *
     * @param[in] dev       network device descriptor
     * @param[in] vector    io vector array to send
     * @param[in] count     nr of entries in vector
     *
     * @return nr of bytes sent, or <=0 on error
     */
    int (*send)(netdev2_t *dev, const struct iovec *vector, int count);

    /**
     * @brief Get a received frame
     *
     * Supposed to be called from netdev2_event_handler().
     *
     * @param[in]   dev     network device descriptor
     * @param[out]  buf     buffer to write into or NULL
     * @param[in]   len     maximum nr. of bytes to read
     *
     * @return <=0 on error
     * @return nr of bytes read if buf != NULL
     * @return packet size if buf == NULL
     */
    int (*recv)(netdev2_t *dev, char* buf, int len);

    /**
     * @brief the driver's initialization function
     *
     * @return <=0 on error, >0 on success
     */
    int (*init)(netdev2_t *dev);

    /**
     * @brief a driver's user-space ISR handler
     *
     * This function will be called from a network stack's loop when being notified
     * by netdev2_isr.
     *
     * It is supposed to call netdev2_event_handler for each occuring event.
     *
     * See receive packet flow description for details.
     *
     * @param[in]   dev     network device descriptor
     */
    void (*isr)(netdev2_t *dev);

    /**
     * @brief   Get an option value from a given network device
     *
     * @param[in]   dev     network device descriptor
     * @param[in]   opt     option type
     * @param[out]  value   pointer to store the option's value in
     * @param[in]   max_len maximal amount of byte that fit into @p value
     *
     * @return              number of bytes written to @p value
     * @return              <0 on error
     */
    int (*get)(netdev2_t *dev, netopt_t opt,
               void *value, size_t max_len);

    /**
     * @brief   Set an option value for a given network device
     *
     * @param[in] dev       network device descriptor
     * @param[in] opt       option type
     * @param[in] value     value to set
     * @param[in] value_len the length of @p value
     *
     * @return              number of bytes used from @p value
     * @return              <0 on error
     */
    int (*set)(netdev2_t *dev, netopt_t opt,
               void *value, size_t value_len);
} netdev2_driver_t;

#ifdef __cplusplus
}
#endif
/** @} */
#endif /* NETDEV2_H */