nuttx/include/nuttx/fs/automount.h

/****************************************************************************
 * include/nuttx/audio/automount.h
 *
 *   Copyright (C) 2014 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.
 *
 ****************************************************************************/

#ifndef __INCLUDE_NUTTX_AUDIO_AUTOMOUNT_H
#define __INCLUDE_NUTTX_AUDIO_AUTOMOUNT_H

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

#include <stdint.h>
#include <stdbool.h>

#include <nuttx/irq.h>

#ifdef CONFIG_FS_AUTOMOUNTER

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* Configuration ************************************************************
 * Automounter configuration
 *   CONFIG_FS_AUTOMOUNTER - Enables automount support
 *
 * Prequisites:
 *   CONFIG_SCHED_WORKQUEUE -  Work queue support is required
 *   And others that would only matter if you are working in a very minimal
 *   configuration.
 */

/* Helper macros ************************************************************/

#define AUTOMOUNT_ATTACH(s,isr,arg) ((s)->attach(s,isr,arg))
#define AUTOMOUNT_DETACH(s)         ((s)->attach(s,NULL,NULL))
#define AUTOMOUNT_ENABLE(s)         ((s)->enable(s,true))
#define AUTOMOUNT_DISABLE(s)        ((s)->enable(s,false))
#define AUTOMOUNT_INSERTED(s)       ((s)->inserted(s))

/****************************************************************************
 * Public Types
 ****************************************************************************/
/* This is the type of the automount media change handler.  The lower level
 * code will intercept the interrupt and provide the upper level with the
 * private data that was provided when the interrupt was attached and will
 * also provide an indication if the media was inserted or removed.
 */

struct automount_lower_s; /* Forward reference.  Defined below */

typedef CODE int
  (*automount_handler_t)(FAR const struct automount_lower_s *lower,
                         FAR void *arg, bool inserted);

/* A reference to a structure of this type must be passed to the FS
 * automounter.  This structure provides information about the volume to be
 * mounted and provides board-specific hooks.
 *
 * Memory for this structure is provided by the caller.  It is not copied
 * by the automounter and is presumed to persist while the automounter
 * is active.
 */

struct automount_lower_s
{
  /* Volume characterization */

  FAR const char *fstype;     /* Type of file system */
  FAR const char *blockdev;   /* Path to the block device */
  FAR const char *mountpoint; /* Location to mount the volume */

  /* Debounce delay in system clock ticks.  Automount operation will not
   * be performed until the insertion/removal state has been unchanges
   * for this duration.
   */

  uint32_t ddelay;

  /* Unmount delay time in system clock ticks.  If a volume has open
   * references at the time that the media is removed, then we will be
   * unable to unmount it.  In that case, hopefully, the clients of the
   * mount will eventually fail with file access errors and eventually close
   * their references.  So, at some time later, it should be possible to
   * unmount the volume.  This delay specifies the time between umount
   * retries.
   */

  uint32_t udelay;

  /* Interrupt related operations all hidden behind callbacks to isolate the
   * automounter from differences in interrupt handling by varying boards
   * and MCUs.  Board interrupts should be configured both insertion and
   * removal of the media can be detected.
   *
   * attach  - Attach or detach the media change interrupt handler to the
   *           board level interrupt
   * enable  - Enable or disable the media change interrupt
   */

  CODE int (*attach)(FAR const struct automount_lower_s *lower,
                      automount_handler_t isr, FAR void *arg);
  CODE void (*enable)(FAR const struct automount_lower_s *lower,
                      bool enable);
  CODE bool (*inserted)(FAR const struct automount_lower_s *lower);
};

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

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Name: automount_initialize
 *
 * Description:
 *   Configure the automounter.
 *
 * Input Parameters:
 *   lower - Persistent board configuration data
 *
 * Returned Value:
 *   A void* handle.  The only use for this handle is with automount_uninitialize().
 *   NULL is returned on any failure.
 *
 ****************************************************************************/

FAR void *automount_initialize(FAR const struct automount_lower_s *lower);

/****************************************************************************
 * Name: automount_uninitialize
 *
 * Description:
 *   Stop the automounter and free resources that it used.  NOTE that the
 *   mount is left in its last state mounted/unmounted state.
 *
 * Input Parameters:
 *   handle - The value previously returned by automount_initialize();
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void automount_uninitialize(FAR void *handle);

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* CONFIG_FS_AUTOMOUNTER */
#endif /* __INCLUDE_NUTTX_AUDIO_AUTOMOUNT_H */