text: /****************************************************************************
   * fs/smartfs/smartfs.h
   *
   *   Copyright (C) 2013 Ken Pettit. All rights reserved.
   *   Author: Ken Pettit <pettitkd@gmail.com>
   *
   * References: Linux/Documentation/filesystems/romfs.txt
   *
   * 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.h>
  #include <nuttx/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
  
  #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))
  
  /****************************************************************************
   * 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.
   */
  
  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 */
  };
  
  /* 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 */
    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
  {
  #ifdef CONFIG_SMARTFS_MULTI_ROOT_DIRS
    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 Variables
   ****************************************************************************/
  
  /****************************************************************************
   * 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);
  
  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);
  
  struct file;        /* Forward references */
  struct inode;
  struct fs_dirent_s;
  struct statfs;
  struct stat;
  
  #endif /* __FS_SMARTFS_SMARTFS_H */
  