px4-firmware/nuttx/fs/fs_registerblockdriver.c

/****************************************************************************
 * fs/fs_registerblockdriver.c
 *
 *   Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * 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 <sys/types.h>
#include <errno.h>

#include <nuttx/fs/fs.h>

#include "fs_internal.h"

/****************************************************************************
 * Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Public Variables
 ****************************************************************************/

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

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

/****************************************************************************
 * Name: register_blockdriver
 *
 * Description:
 *   Register a block driver inode the pseudo file system.
 *
 * Input parameters:
 *   path - The path to the inode to create
 *   bops - The block driver operations structure
 *   mode - inmode priviledges (not used)
 *   priv - Private, user data that will be associated with the inode.
 *
 * Returned Value:
 *   Zero on success (with the inode point in 'inode'); A negated errno
 *   value is returned on a failure (all error values returned by
 *   inode_reserve):
 *
 *   EINVAL - 'path' is invalid for this operation
 *   EEXIST - An inode already exists at 'path'
 *   ENOMEM - Failed to allocate in-memory resources for the operation
 *
 ****************************************************************************/

int register_blockdriver(FAR const char *path,
                         FAR const struct block_operations *bops,
                         mode_t mode, FAR void *priv)
{
  FAR struct inode *node;
  int ret;

  /* Insert an inode for the device driver -- we need to hold the inode
   * semaphore to prevent access to the tree while we this.  This is because
   * we will have a momentarily bad true until we populate the inode with
   * valid data.
   */

  inode_semtake();
  ret = inode_reserve(path, &node);
  if (ret >= 0)
    {
      /* We have it, now populate it with block driver specific information. */

      INODE_SET_BLOCK(node);

      node->u.i_bops  = bops;
#ifdef CONFIG_FILE_MODE
      node->i_mode    = mode;
#endif
      node->i_private = priv;
      ret             = OK;
    }

  inode_semgive();
  return ret;
}