/****************************************************************************
 * fs/smartfs/smartfs.h
 *
 *   Copyright (C) 2013-2014 Ken Pettit. All rights reserved.
 *   Author: Ken Pettit <pettitkd@gmail.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.
 *
 ****************************************************************************/

#ifndef __FS_SMARTFS_SMARTFS_H
#define __FS_SMARTFS_SMARTFS_H

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

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <semaphore.h>

#include <nuttx/mtd/mtd.h>
#include <nuttx/fs/smart.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* SMART Definitions ********************************************************/
/* General SMART organization.  The following example assumes 4 logical
 * sectors per FLASH erase block.  The actual relationship is determined by
 * the FLASH geometry reported by the MTD driver.
 *
 * ERASE LOGICAL                   Sectors begin with a sector header.  Sectors may
 * BLOCK SECTOR      CONTENTS      be marked as "released," pending garbage collection
 *   n   4*n     --+---------------+
 *             Hdr |LLLLLLLLLLLLLLL| Logical sector number (2 bytes)
 *                 |QQQQQQQQQQQQQQQ| Sequence number (2 bytes)
 *                 |SSSSSSSSSSSSSSS| Status bits (1 byte)
 *                 +---------------+
 *                 |TTTTTTTTTTTTTTT| Sector Type (dir or file) (1 byte)
 *                 |NNNNNNNNNNNNNNN| Number of next logical sector in chain
 *                 |UUUUUUUUUUUUUUU| Number of bytes used in this sector
 *                 |               |
 *                 | (Sector Data) |
 *                 |               |
 *       4*n+1   --+---------------+
 *      Sector Hdr |LLLLLLLLLLLLLLL| Logical sector number (2 bytes)
 *                 |QQQQQQQQQQQQQQQ| Sequence number (2 bytes)
 *                 |SSSSSSSSSSSSSSS| Status bits (1 byte)
 *                 +---------------+
 *          FS Hdr |TTTTTTTTTTTTTTT| Sector Type (dir or file) (1 byte)
 *                 |NNNNNNNNNNNNNNN| Number of next logical sector in chain
 *                 |UUUUUUUUUUUUUUU| Number of bytes used in this sector
 *                 |               |
 *                 | (Sector Data) |
 *                 |               |
 *       4*n+2   --+---------------+
 *      Sector Hdr |LLLLLLLLLLLLLLL| Logical sector number (2 bytes)
 *                 |QQQQQQQQQQQQQQQ| Sequence number (2 bytes)
 *                 |SSSSSSSSSSSSSSS| Status bits (1 byte)
 *                 +---------------+
 *          FS Hdr |TTTTTTTTTTTTTTT| Sector Type (dir or file) (1 byte)
 *                 |NNNNNNNNNNNNNNN| Number of next logical sector in chain
 *                 |UUUUUUUUUUUUUUU| Number of bytes used in this sector
 *                 |               |
 *                 | (Sector Data) |
 *                 |               |
 *       4*n+3   --+---------------+
 *      Sector Hdr |LLLLLLLLLLLLLLL| Logical sector number (2 bytes)
 *                 |QQQQQQQQQQQQQQQ| Sequence number (2 bytes)
 *                 |SSSSSSSSSSSSSSS| Status bits (1 byte)
 *                 +---------------+
 *          FS Hdr |TTTTTTTTTTTTTTT| Sector Type (dir or file) (1 byte)
 *                 |NNNNNNNNNNNNNNN| Number of next logical sector in chain
 *                 |UUUUUUUUUUUUUUU| Number of bytes used in this sector
 *                 |               |
 *                 | (Sector Data) |
 *                 |               |
 *  n+1  4*(n+1) --+---------------+
 *      Sector Hdr |LLLLLLLLLLLLLLL| Logical sector number (2 bytes)
 *                 |QQQQQQQQQQQQQQQ| Sequence number (2 bytes)
 *                 |SSSSSSSSSSSSSSS| Status bits (1 byte)
 *                 +---------------+
 *          FS Hdr |TTTTTTTTTTTTTTT| Sector Type (dir or file) (1 byte)
 *                 |NNNNNNNNNNNNNNN| Number of next logical sector in chain
 *                 |UUUUUUUUUUUUUUU| Number of bytes used in this sector
 *                 |               |
 *                 |               |
 *                 |               |
 *               --+---------------+
 *
 * General operation:
 *   Physical sectors are allocated and assigned a logical sector number
 *   and a starting sequence number of zero.
 *
 * SECTOR HEADER:
 *   The sector header (first 5 bytes) tracks the state of each sector and
 *   is used by the SMART MTD block driver.  At the block level, there is
 *   no notion of sector chaining, only allocated sectors within erase
 *   blocks.
 *
 * FILE SYSTEM (FS) HEADER:
 *   The file system header (next 5 bytes) tracks file and directory entries
 *   and chains.
 *
 * SMART Limitations:
 * 1. SMART currently depends on the underlying MTD block driver supporting
 *    single-byte programming operation.  This is due to the method it
 *    uses for marking a sector as "released", committed, etc.
 * 2. Garbage collection can occur when a new sector is allocated or when
 *    existing sector data is overwritten with new data. Thus, occasionally,
 *    file writing may take longer than other times.
 * 3. The implementation curently does not track bad blocks on the device.
 * 4. There is no true wear-leveling implemented yet, though provesion have
 *    been made to reserve logical sectors to allow it to be added using
 *    a "sector aging" tracking mechanism.
 */

/* Values for SMART inode state.
 *
 * SMART_STATE_FILE    - The inode is a valid usuable, file
 * INODE_STATE_DELETED - The inode has been deleted.
 * Other values        - The inode is bad and has an invalid state.
 *
 * Care is taken so that the VALID to DELETED transition only involves burning
 * bits from the erased to non-erased state.
 */

#define INODE_STATE_FILE          (CONFIG_NXFFS_ERASEDSTATE ^ 0x22)
#define INODE_STATE_DELETED       (CONFIG_NXFFS_ERASEDSTATE ^ 0xaa)

/* Directory entry flag definitions */

#define SMARTFS_DIRENT_EMPTY      0x8000  /* Set to non-erase state when entry used */
#define SMARTFS_DIRENT_ACTIVE     0x4000  /* Set to erase state when entry is active */
#define SMARTFS_DIRENT_TYPE       0x2000  /* Indicates the type of entry (file/dir) */
#define SMARTFS_DIRENT_DELETING   0x1000  /* Directory entry is being deleted */
#define SMARTFS_DIRENT_RESERVED   0x0E00  /* Reserved bits */
#define SMARTFS_DIRENT_MODE       0x01FF  /* Mode the file was created with */

#define SMARTFS_DIRENT_TYPE_DIR   0x2000
#define SMARTFS_DIRENT_TYPE_FILE  0x0000

/* Number of bytes in the SMART magic sequences */

#define SMART_MAGICSIZE           4

/* Quasi-standard definitions */

#ifndef MIN
#  define MIN(a,b)                (a < b ? a : b)
#endif

#ifndef MAX
#  define MAX(a,b)                (a > b ? a : b)
#endif

/* Underlying MTD Block driver access functions */

#define FS_BOPS(f)        (f)->fs_blkdriver->u.i_bops
#define FS_IOCTL(f,c,a)   (FS_BOPS(f)->ioctl ? FS_BOPS(f)->ioctl((f)->fs_blkdriver,c,a) : (-ENOSYS))

/* The logical sector number of the root directory. */

#define SMARTFS_ROOT_DIR_SECTOR   3

/* Defines the sector types */

#define SMARTFS_SECTOR_TYPE_DIR   1
#define SMARTFS_SECTOR_TYPE_FILE  2

#ifndef CONFIG_SMARTFS_DIRDEPTH
#  define CONFIG_SMARTFS_DIRDEPTH 8
#endif

/* Buffer flags (when CRC enabled) */

#define SMARTFS_BFLAG_DIRTY       0x01    /* Set if data changed in the sector */
#define SMARTFS_BFLAG_NEWALLOC    0x02    /* Set if sector not written since alloc */

#define SMARTFS_ERASEDSTATE_16BIT (uint16_t) ((CONFIG_SMARTFS_ERASEDSTATE << 8) | \
                                    CONFIG_SMARTFS_ERASEDSTATE)

#ifndef offsetof
#define offsetof(type, member)   ( (size_t) &( ( (type *) 0)->member))
#endif

#define SMARTFS_NEXTSECTOR(h)    ( *((uint16_t *) h->nextsector))
#define SMARTFS_USED(h)          ( *((uint16_t *) h->used))

#ifdef CONFIG_MTD_SMART_ENABLE_CRC
#define CONFIG_SMARTFS_USE_SECTOR_BUFFER
#endif

/****************************************************************************
 * Public Types
 ****************************************************************************/

/* This structure defines each packed block on the FLASH media */

/* This is an in-memory representation of the SMART inode as extracted from
 * FLASH and with additional state information.
 */

struct smartfs_entry_s
{
  uint16_t          firstsector;  /* Sector number of the name */
  uint16_t          dsector;      /* Sector number of the directory entry */
  uint16_t          doffset;      /* Offset of the directory entry */
  uint16_t          dfirst;       /* 1st sector number of the directory entry */
  uint16_t          flags;        /* Flags, including mode */
  FAR char          *name;        /* inode name */
  uint32_t          utc;          /* Time stamp */
  uint32_t          datlen;       /* Length of inode data */
};

/* This is an on-device representation of the SMART inode it esists on
 * the FLASH.
 */

struct smartfs_entry_header_s
{
  uint16_t          flags;        /* Flags, including permissions:
                                      15:   Empty entry
                                      14:   Active entry
                                      12-0: Permissions bits */
  int16_t           firstsector;  /* Sector number of the name */
  uint32_t          utc;          /* Time stamp */
  char              name[0];      /* inode name */
};

/* This structure describes the smartfs header at the start of each
 * sector.  It manages the sector chain and used bytes in the sector.
 */

#if defined(CONFIG_MTD_SMART_ENABLE_CRC) && defined(CONFIG_SMART_CRC_32)
struct smartfs_chain_header_s
{
  uint8_t           nextsector[4];/* Next logical sector in the chain */
  uint8_t           used[4];      /* Number of bytes used in this sector */
  uint8_t           type;         /* Type of sector entry (file or dir) */
};
#elif defined(CONFIG_MTD_SMART_ENABLE_CRC) && defined(CONFIG_SMART_CRC_16)
struct smartfs_chain_header_s
{
  uint8_t           type;         /* Type of sector entry (file or dir) */
  uint8_t           nextsector[2];/* Next logical sector in the chain */
  uint8_t           used[2];      /* Number of bytes used in this sector */
};
#else
struct smartfs_chain_header_s
{
  uint8_t           type;         /* Type of sector entry (file or dir) */
  uint8_t           nextsector[2];/* Next logical sector in the chain */
  uint8_t           used[2];      /* Number of bytes used in this sector */
};
#endif

/* This structure describes the state of one open file.  This structure
 * is protected by the volume semaphore.
 */

struct smartfs_ofile_s
{
  struct smartfs_ofile_s   *fnext;      /* Supports a singly linked list */
#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
  uint8_t*                  buffer;     /* Sector buffer to reduce writes */
  uint8_t                   bflags;     /* Buffer flags */
#endif
  int16_t                   crefs;      /* Reference count */
  mode_t                    oflags;     /* Open mode */
  struct smartfs_entry_s    entry;      /* Describes the SMARTFS inode entry */
  size_t                    filepos;    /* Current file position */
  uint16_t                  currsector; /* Current sector of filepos */
  uint16_t                  curroffset; /* Current offset in sector */
  uint16_t                  byteswritten;/* Count of bytes written to currsector
                                          * that have not been recorded in the
                                          * sector yet.  We delay updating the
                                          * used field until the file is closed,
                                          * a seek, or more data is written that
                                          * causes the sector to change. */
};

/* This structure represents the overall mountpoint state.  An instance of this
 * structure is retained as inode private data on each mountpoint that is
 * mounted with a smartfs filesystem.
 */

struct smartfs_mountpt_s
{
#if defined(CONFIG_SMARTFS_MULTI_ROOT_DIRS) || defined(CONFIG_FS_PROCFS)
  struct smartfs_mountpt_s   *fs_next;      /* Pointer to next SMART filesystem */
#endif
  FAR struct inode           *fs_blkdriver; /* Our underlying block device */
  sem_t                      *fs_sem;       /* Used to assure thread-safe access */
  FAR struct smartfs_ofile_s *fs_head;      /* A singly-linked list of open files */
  bool                        fs_mounted;   /* true: The file system is ready */
  struct smart_format_s       fs_llformat;  /* Low level device format info */
  char                       *fs_rwbuffer;  /* Read/Write working buffer */
  char                       *fs_workbuffer;/* Working buffer */
  uint8_t                     fs_rootsector;/* Root directory sector num */
};

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

/****************************************************************************
 * Internal function prototypes
 ****************************************************************************/

/* Semaphore access for internal use */

void smartfs_semtake(struct smartfs_mountpt_s *fs);
void smartfs_semgive(struct smartfs_mountpt_s *fs);

/* Forward references for utility functions */

struct smartfs_mountpt_s;

/* Utility functions */

int smartfs_mount(struct smartfs_mountpt_s *fs, bool writeable);

int smartfs_unmount(struct smartfs_mountpt_s *fs);

int smartfs_finddirentry(struct smartfs_mountpt_s *fs,
        struct smartfs_entry_s *direntry, const char *relpath,
        uint16_t *parentdirsector, const char **filename);

int smartfs_createentry(struct smartfs_mountpt_s *fs,
        uint16_t parentdirsector, const char* filename,
        uint16_t type,
        mode_t mode, struct smartfs_entry_s *direntry,
        uint16_t sectorno, FAR struct smartfs_ofile_s *sf);

int smartfs_deleteentry(struct smartfs_mountpt_s *fs,
        struct smartfs_entry_s *entry);

int smartfs_countdirentries(struct smartfs_mountpt_s *fs,
        struct smartfs_entry_s *entry);

int smartfs_truncatefile(struct smartfs_mountpt_s *fs,
        struct smartfs_entry_s *entry, FAR struct smartfs_ofile_s *sf);

uint16_t smartfs_rdle16(FAR const void *val);

void smartfs_wrle16(void *dest, uint16_t val);

uint32_t smartfs_rdle32(FAR const void *val);

void smartfs_wrle32(uint8_t *dest, uint32_t val);

#if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_SMARTFS)
struct smartfs_mountpt_s* smartfs_get_first_mount(void);
#endif

#if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_SMARTFS)
struct smartfs_mountpt_s* smartfs_get_first_mount(void);
#endif

struct file;        /* Forward references */
struct inode;
struct fs_dirent_s;
struct statfs;
struct stat;

#endif /* __FS_SMARTFS_SMARTFS_H */