net/can/can_input.c

/****************************************************************************
 * net/can/can_input.c
 * Handling incoming packet input
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_CAN)

#include <errno.h>
#include <debug.h>

#include <nuttx/net/netdev.h>
#include <nuttx/net/can.h>

#include "devif/devif.h"
#include "can/can.h"

/****************************************************************************
 * Public Data
 ****************************************************************************/

const uint8_t can_dlc_to_len[16] =
{
    0,
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    12,
    16,
    20,
    24,
    32,
    48,
    64,
};
const uint8_t len_to_can_dlc[65] =
{
    0,
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    9,
    9,
    9,
    10,
    10,
    10,
    10,
    11,
    11,
    11,
    11,
    12,
    12,
    12,
    12,
    13,
    13,
    13,
    13,
    13,
    13,
    13,
    13,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    14,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
    15,
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: can_input_conn
 *
 * Description:
 *   Handle incoming packet input
 *
 * Input Parameters:
 *   dev  - The device driver structure containing the received packet
 *   conn - A pointer to the CAN connection structure
 *
 * Returned Value:
 *   OK     The packet has been processed  and can be deleted
 *  -EAGAIN There is a matching connection, but could not dispatch the packet
 *          yet.  Useful when a packet arrives before a recv call is in
 *          place.
 *
 * Assumptions:
 *   This function can be called from an interrupt.
 *
 ****************************************************************************/

static int can_input_conn(FAR struct net_driver_s *dev,
                          FAR struct can_conn_s *conn)
{
  uint16_t flags;
  uint16_t buflen = dev->d_len;
  int ret = OK;

  /* Setup for the application callback */

  dev->d_appdata = dev->d_buf;
  dev->d_sndlen  = 0;
  dev->d_len     = buflen;

  /* Perform the application callback */

  flags = can_callback(dev, conn, CAN_NEWDATA);

  /* If the operation was successful, the CAN_NEWDATA flag is removed
   * and thus the packet can be deleted (OK will be returned).
   */

  if ((flags & CAN_NEWDATA) != 0)
    {
      /* No.. the packet was not processed now.  Return -EAGAIN so
       * that the driver may retry again later.  We still need to
       * set d_len to zero so that the driver is aware that there
       * is nothing to be sent.
       */

      nwarn("WARNING: Packet not processed\n");
      ret = -EAGAIN;
    }

  return ret;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: can_in
 *
 * Description:
 *   Handle incoming packet input
 *
 * Input Parameters:
 *   dev - The device driver structure containing the received packet
 *
 * Returned Value:
 *   OK     The packet has been processed  and can be deleted
 *  -EAGAIN There is a matching connection, but could not dispatch the packet
 *          yet.  Useful when a packet arrives before a recv call is in
 *          place.
 *
 * Assumptions:
 *   This function can be called from an interrupt.
 *
 ****************************************************************************/

static int can_in(FAR struct net_driver_s *dev)
{
  FAR struct can_conn_s *conn = can_active(dev, NULL);
  FAR struct can_conn_s *nextconn;

  /* Do we have second connection that can hold this packet? */

  while ((nextconn = can_active(dev, conn)) != NULL)
    {
      /* Yes... There are multiple listeners on the same dev.
       * We need to clone the packet and deliver it to each listener.
       */

      FAR struct iob_s *iob = netdev_iob_clone(dev, false);

      if (iob == NULL)
        {
          nerr("ERROR: IOB clone failed.\n");
          break; /* We can still process one time without clone. */
        }

      can_input_conn(dev, conn);

      netdev_iob_replace(dev, iob);
      conn = nextconn;
    }

  /* We can deliver the packet directly to the last listener. */

  return can_input_conn(dev, conn);
}

/****************************************************************************
 * Name: can_input
 *
 * Description:
 *   Handle incoming packet input
 *
 * Input Parameters:
 *   dev - The device driver structure containing the received packet
 *
 * Returned Value:
 *   OK     The packet has been processed  and can be deleted
 *  -EAGAIN There is a matching connection, but could not dispatch the packet
 *          yet.  Useful when a packet arrives before a recv call is in
 *          place.
 *
 * Assumptions:
 *   This function can be called from an interrupt.
 *
 ****************************************************************************/

int can_input(FAR struct net_driver_s *dev)
{
  FAR uint8_t *buf;
  int ret;

  if (dev->d_iob != NULL)
    {
      buf = dev->d_buf;

      /* Set the device buffer to l2 */

      dev->d_buf = NETLLBUF;
      ret = can_in(dev);

      dev->d_buf = buf;

      return ret;
    }

  return netdev_input(dev, can_in, false);
}

#endif /* CONFIG_NET && CONFIG_NET_CAN */