nuttx/wireless/ieee802154/mac802154_device.c

/****************************************************************************
 * drivers/ieee802154/mac802154_device.c
 *
 *   Copyright (C) 2017 Verge Inc. All rights reserved.
 *   Author: Anthony Merlino <anthony@vergeaero.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

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

#include <nuttx/config.h>

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#include <nuttx/arch.h>
#include <nuttx/kmalloc.h>

#include <nuttx/wireless/ieee802154/ieee802154_mac.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/* Device naming ************************************************************/

#define DEVNAME_FMT    "/dev/ieee%d"
#define DEVNAME_FMTLEN (9 + 3 + 1)

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct mac802154_devwrapper_s
{
  MACHANDLE md_mac;    /* Saved binding to the mac layer */
  sem_t md_exclsem;    /* Exclusive device access */

  /* The following is a singly linked list of open references to the
   * MAC device.
   */

  FAR struct mac802154_open_s *md_open;
  FAR struct mac802154dev_dwait_s *md_dwait;
};

/* This structure describes the state of one open mac driver instance */

struct mac802154_open_s
{
  /* Supports a singly linked list */

  FAR struct mac802154_open_s *md_flink;

  /* The following will be true if we are closing */

  volatile bool md_closing;
};

struct mac802154dev_dwait_s
{
  uint8_t mw_handle;  /* The msdu handle identifying the frame */
  sem_t mw_sem;       /* The semaphore used to signal the completion */
  int status;         /* The success/error of the transaction */

  /* Supports a singly linked list */

  FAR struct mac802154dev_dwait_s *mw_flink;
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

 /* Semaphore helpers */

static inline int mac802154dev_takesem(sem_t *sem);
#define mac802154dev_givesem(s) sem_post(s);

static int  mac802154dev_open(FAR struct file *filep);
static int  mac802154dev_close(FAR struct file *filep);
static ssize_t mac802154dev_read(FAR struct file *filep, FAR char *buffer,
              size_t len);
static ssize_t mac802154dev_write(FAR struct file *filep,
              FAR const char *buffer, size_t len);
static int  mac802154dev_ioctl(FAR struct file *filep, int cmd,
              unsigned long arg);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const struct file_operations mac802154dev_fops =
{
  mac802154dev_open , /* open */
  mac802154dev_close, /* close */
  mac802154dev_read , /* read */
  mac802154dev_write, /* write */
  NULL,               /* seek */
  mac802154dev_ioctl  /* ioctl */
#ifndef CONFIG_DISABLE_POLL
  , NULL              /* poll */
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
  , NULL               /* unlink */
#endif
};

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

/****************************************************************************
 * Name: mac802154dev_semtake
 *
 * Description:
 *   Acquire the semaphore used for access serialization.
 *
 ****************************************************************************/

static inline int mac802154dev_takesem(sem_t *sem)
{
  /* Take a count from the semaphore, possibly waiting */

  if (sem_wait(sem) < 0)
    {
      /* EINTR is the only error that we expect */

      int errcode = get_errno();
      DEBUGASSERT(errcode == EINTR);
      return -errcode;
    }

  return OK;
}

/****************************************************************************
 * Name: mac802154dev_open
 *
 * Description:
 *   Open the 802.15.4 MAC character device.
 *
 ****************************************************************************/

static int mac802154dev_open(FAR struct file *filep)
{
  FAR struct inode *inode;
  FAR struct mac802154_devwrapper_s *dev;
  FAR struct mac802154_open_s *opriv;
  int ret;

  DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
  inode = filep->f_inode;

  dev   = inode->i_private;
  DEBUGASSERT(dev != NULL);

  /* Get exclusive access to the MAC driver data structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154dev_takesem failed: %d\n", ret);
      return ret;
    }

  /* Allocate a new open struct */

  opriv = (FAR struct mac802154_open_s *)
    kmm_zalloc(sizeof(struct mac802154_open_s));

  if (!opriv)
    {
      wlerr("ERROR: Failed to allocate new open struct\n");
      ret = -ENOMEM;
      goto errout_with_sem;
    }
  
  /* Attach the open struct to the device */

  opriv->md_flink = dev->md_open;
  dev->md_open = opriv;

  /* Attach the open struct to the file structure */

  filep->f_priv = (FAR void *)opriv;
  ret = OK;

errout_with_sem:
  mac802154dev_givesem(&dev->md_exclsem);
  return ret;
}

/****************************************************************************
 * Name: mac802154dev_close
 *
 * Description:
 *   Close the 802.15.4 MAC character device.
 *
 ****************************************************************************/

static int mac802154dev_close(FAR struct file *filep)
{
  FAR struct inode *inode;
  FAR struct mac802154_devwrapper_s *dev;
  FAR struct mac802154_open_s *opriv;
  FAR struct mac802154_open_s *curr;
  FAR struct mac802154_open_s *prev;
  irqstate_t flags;
  bool closing;
  int ret;

  DEBUGASSERT(filep && filep->f_priv && filep->f_inode);
  opriv = filep->f_priv;
  inode = filep->f_inode;
  DEBUGASSERT(inode->i_private);
  dev = (FAR struct mac802154_devwrapper_s *)inode->i_private;

  /* Handle an improbable race conditions with the following atomic test
   * and set.
   *
   * This is actually a pretty feeble attempt to handle this.  The
   * improbable race condition occurs if two different threads try to
   * close the joystick driver at the same time.  The rule:  don't do
   * that!  It is feeble because we do not really enforce stale pointer
   * detection anyway.
   */

  flags = enter_critical_section();
  closing = opriv->md_closing;
  opriv->md_closing = true;
  leave_critical_section(flags);

  if (closing)
    {
      /* Another thread is doing the close */

      return OK;
    }

  /* Get exclusive access to the driver structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154_takesem failed: %d\n", ret);
      return ret;
    }

  /* Find the open structure in the list of open structures for the device */

  for (prev = NULL, curr = dev->md_open;
       curr && curr != opriv;
       prev = curr, curr = curr->md_flink);

  DEBUGASSERT(curr);
  if (!curr)
    {
      wlerr("ERROR: Failed to find open entry\n");
      ret = -ENOENT;
      goto errout_with_exclsem;
    }

  /* Remove the structure from the device */

  if (prev)
    {
      prev->md_flink = opriv->md_flink;
    }
  else
    {
      dev->md_open = opriv->md_flink;
    }

  /* And free the open structure */

  kmm_free(opriv);
  ret = OK;

errout_with_exclsem:
  mac802154dev_givesem(&dev->md_exclsem);
  return ret;
}

/****************************************************************************
 * Name: mac802154dev_read
 *
 * Description:
 *   Return the last received packet.
 *
 ****************************************************************************/

static ssize_t mac802154dev_read(FAR struct file *filep, FAR char *buffer,
                                 size_t len)
{
  FAR struct inode *inode;
  FAR struct mac802154_devwrapper_s *dev;
  int ret;

  DEBUGASSERT(filep && filep->f_inode);
  inode = filep->f_inode;
  DEBUGASSERT(inode->i_private);
  dev = (FAR struct mac802154_devwrapper_s *)inode->i_private;

  /* Check to make sure that the buffer is big enough to hold at least one
   * packet.
   */

  if (len < sizeof(struct ieee802154_frame_s))
    {
      wlerr("ERROR: buffer too small: %lu\n", (unsigned long)len);
      return -EINVAL;
    }

  /* Get exclusive access to the driver structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154dev_takesem failed: %d\n", ret);
      return ret;
    }

  /* TODO: Add code to read a packet and return it */
  ret = -ENOTSUP;

  mac802154dev_givesem(&dev->md_exclsem);
  return ret;
}

/****************************************************************************
 * Name: mac802154dev_write
 *
 * Description:
 *   Send a packet over the IEEE802.15.4 network.
 *
 ****************************************************************************/

static ssize_t mac802154dev_write(FAR struct file *filep,
                                  FAR const char *buffer, size_t len)
{
  FAR struct inode *inode;
  FAR struct mac802154_devwrapper_s *dev;
  FAR struct ieee802154_data_req_s *req;
  struct mac802154dev_dwait_s dwait;
  int ret;

  DEBUGASSERT(filep && filep->f_inode);
  inode = filep->f_inode;
  DEBUGASSERT(inode->i_private);
  dev  = (FAR struct mac802154_devwrapper_s *)inode->i_private;

  /* Check to make sure that the buffer is big enough to hold at least one
   * packet.
   */

  if (len < sizeof(struct ieee802154_frame_s))
    {
      wlerr("ERROR: buffer too small: %lu\n", (unsigned long)len);
      return -EINVAL;
    }
  
  DEBUGASSERT(buffer != NULL);
  frame = *(FAR struct ieee802154_frame_s *)buffer;

  /* Get exclusive access to the driver structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154dev_takesem failed: %d\n", ret);
      return ret;
    }

  /* Setup the wait struct */

  dwait.mw_handle = req->msdu_handle;

  /* Link the wait struct */

  dwait.mw_flink = dev->md_dwait;
  dev->md_wait = &dwait;

  /* Pass the request to the MAC layer */

  ret = dev->md_mac->ops.req_data(dev->md_mac, req);

  mac802154dev_givesem(&dev->md_exclsem);

  if (ret < 0) 
    {
      wlerr("ERROR: req_data failed %d\n", ret);
      return ret;
    }

  /* Wait for the DATA.confirm callback to be called for our handle */

  sem_wait(dwait.mw_sem);

  /* The unlinking of the wait struct happens inside the callback. This
   * is more efficient since it will already have to find the struct in
   * the list in order to perform the sem_post.
   */

  return dwait.status;
}

/****************************************************************************
 * Name: mac802154dev_ioctl
 *
 * Description:
 *   Control the MAC layer via MLME IOCTL commands.
 *
 ****************************************************************************/

static int mac802154dev_ioctl(FAR struct file *filep, int cmd,
                                   unsigned long arg)
{
  FAR struct inode *inode;
  FAR struct mac802154_devwrapper_s *dev;
  MACHANDLE mac;
  int ret;

  DEBUGASSERT(filep != NULL && filep->f_priv != NULL &&
              filep->f_inode != NULL);
  inode = filep->f_inode;
  DEBUGASSERT(inode->i_private);
  dev = (FAR struct mac802154_devwrapper_s *)inode->i_private;

  /* Get exclusive access to the driver structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154dev_takesem failed: %d\n", ret);
      return ret;
    }

  /* Handle the ioctl command */

  switch (cmd)
    {
      default:
        wlerr("ERROR: Unrecognized command %ld\n", cmd);
        ret = -EINVAL;
        break;
    }

  mac802154dev_givesem(&dev->md_exclsem);
  return ret;
}

void mac802154dev_conf_data(MACHANDLE mac,
                            FAR struct ieee802154_data_conf_s *conf)
{
  FAR struct mac802154_devwrapper_s *dev;
  FAR struct mac802154dev_dwait_s *curr;
  FAR struct mac802154dev_dwait_s *prev;
  int ret;

  /* Get the dev from the callback context.  This should have been set when
   * the char driver was registered.
   *
   * REVISIT: See mac802154_netdev.c
   */
#warning Missing logic

  /* Get exclusive access to the driver structure */

  ret = mac802154dev_takesem(&dev->md_exclsem);
  if (ret < 0)
    {
      wlerr("ERROR: mac802154dev_takesem failed: %d\n", ret);
      return ret;
    }

  /* Search to see if there is a dwait pending for this transaction */

  for (prev = NULL, curr = dev->md_dwait;
       curr && curr->mw_handle != conf->msdu_handle;
       prev = curr, curr = curr->mw_flink);
}

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

/****************************************************************************
 * Name: mac802154dev_register
 *
 * Description:
 *   Register a character driver to access the IEEE 802.15.4 MAC layer from
 *   user-space
 *
 * Input Parameters:
 *   mac - Pointer to the mac layer struct to be registerd.
 *   minor - The device minor number.  The IEEE802.15.4 MAC character device
 *     will be registered as /dev/ieeeN where N is the minor number
 *
 * Returned Values:
 *   Zero (OK) is returned on success.  Otherwise a negated errno value is
 *   returned to indicate the nature of the failure.
 *
 ****************************************************************************/

int mac802154dev_register(MACHANDLE mac, int minor)
{
  FAR struct mac802154_devwrapper_s *dev;
  char devname[DEVNAME_FMTLEN];
  int ret;

  dev = kmm_zalloc(sizeof(struct mac802154_devwrapper_s));
  if (!dev)
    {
      wlerr("ERROR: Failed to allocate device structure\n");
      return -ENOMEM;
    }

  /* Initialize the new mac driver instance */

  dev->md_mac = mac;
  sem_init(&dev->md_exclsem, 0, 1); /* Allow the device to be opened once
                                     * before blocking */

  /* Initialize the callbacks and bind them to the radio
   *
   * REVISIT: See mac802154_netdev.c
   */
#warning Missing logic

  /* Create the character device name */

  snprintf(devname, DEVNAME_FMTLEN, DEVNAME_FMT, minor);

  /* Register the mac character driver */

  ret = register_driver(devname, &mac802154dev_fops, 0666, dev);
  if (ret < 0)
    {
      wlerr("ERROR: register_driver failed: %d\n", ret);
      goto errout_with_priv;
    }

  return OK;

errout_with_priv:
  sem_destroy(&dev->md_exclsem);
  kmm_free(dev);
  return ret;
}