nuttx/fs/fat/fs_fat32.h

/****************************************************************************
 * fs/fat/fs_fat32.h
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

#ifndef __FS_FAT_FS_FAT32_H
#define __FS_FAT_FS_FAT32_H

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

#include <nuttx/config.h>

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

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

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

/****************************************************************************
 * These offsets describes the master boot record (MBR).
 *
 * The following fields are common to FAT12/16/32 (but all value descriptions
 * refer to the interpretation under FAT32).
 *
 * NOTE: This is an older form of the MBR that you will not often see
 * documented.  This older form is used with no partition table and includes
 * the logical content of the FAT boot record use with partitions.
 */

#define MBR_JUMP             0 /*  3@0:  Jump instruction to boot code (ignored) */
#define MBR_OEMNAME          3 /*  8@3:  Usually "MSWIN4.1" */
#define MBR_BYTESPERSEC     11 /*  2@11: Bytes per sector: 512, 1024, 2048, 4096  */
#define MBR_SECPERCLUS      13 /*  1@13: Sectors per allocation unit: 2**n, n=0..7 */
#define MBR_RESVDSECCOUNT   14 /*  2@14: Reserved sector count: Usually 32 */
#define MBR_NUMFATS         16 /*  1@16: Number of FAT data structures: always 2 */
#define MBR_ROOTENTCNT      17 /*  2@17: FAT12/16: Must be 0 for FAT32 */
#define MBR_TOTSEC16        19 /*  2@19: FAT12/16: Must be 0, see MBR_TOTSEC32 */
#define MBR_MEDIA           21 /*  1@21: Media code: f0, f8, f9-fa, fc-ff */
#define MBR_FATSZ16         22 /*  2@22: FAT12/16: Must be 0, see MBR_FATSZ32 */
#define MBR_SECPERTRK       24 /*  2@24: Sectors per track geometry value */
#define MBR_NUMHEADS        26 /*  2@26: Number of heads geometry value */
#define MBR_HIDSEC          28 /*  4@28: Count of hidden sectors preceding FAT */
#define MBR_TOTSEC32        32 /*  4@32: Total count of sectors on the volume */

/* The following fields are only valid for FAT12/16 */

#define MBR16_DRVNUM        36 /*  1@36: Drive number for MS-DOS bootstrap */
                               /*  1@37: Reserved (zero) */
#define MBR16_BOOTSIG       38 /*  1@38: Extended boot signature: 0x29 if following valid */
#define MBR16_VOLID         39 /*  4@39: Volume serial number */
#define MBR16_VOLLAB        43 /* 11@43: Volume label */
#define MBR16_FILESYSTYPE   54 /*  8@54: "FAT12  ", "FAT16  ", or "FAT    " */

#define MBR16_BOOTCODE      62 /* Boot code may be placed in the remainder of the sector */
#define MBR16_BOOTCODESIZE 448

/* The following fields are only valid for FAT32 */

#define MBR32_FATSZ32       36 /*  4@36: Count of sectors occupied by one FAT */
#define MBR32_EXTFLAGS      40 /*  2@40: 0-3:Active FAT, 7=0 both FATS, 7=1 one FAT */
#define MBR32_FSVER         42 /*  2@42: MSB:Major LSB:Minor revision number (0.0) */
#define MBR32_ROOTCLUS      44 /*  4@44: Cluster no. of 1st cluster of root dir */
#define MBR32_FSINFO        48 /*  2@48: Sector number of fsinfo structure. Usually 1. */
#define MBR32_BKBOOTSEC     50 /*  2@50: Sector number of boot record. Usually 6  */
                               /* 12@52: Reserved (zero) */
#define MBR32_DRVNUM        64 /*  1@64: Drive number for MS-DOS bootstrap */
                               /*  1@65: Reserved (zero) */
#define MBR32_BOOTSIG       66 /*  1@66: Extended boot signature: 0x29 if following valid */
#define MBR32_VOLID         67 /*  4@67: Volume serial number */
#define MBR32_VOLLAB        71 /* 11@71: Volume label */
#define MBR32_FILESYSTYPE   82 /*  8@82: "FAT12  ", "FAT16  ", or "FAT    " */

#define MBR32_BOOTCODE      90 /* Boot code may be placed in the remainder of the sector */
#define MBR32_BOOTCODESIZE 420

/* If the sector is not an MBR, then it could have a partition table at
 * this offset.
 */

#define MBR_TABLE          446

/* The magic bytes at the end of the MBR are common to FAT12/16/32 */

#define MBR_SIGNATURE      510 /*  2@510: Valid MBRs have 0x55aa here */

#define BOOT_SIGNATURE16   0xaa55
#define BOOT_SIGNATURE32   0xaa550000

/* The extended boot signature (BS16/32_BOOTSIG) */

#define EXTBOOT_SIGNATURE  0x29

/****************************************************************************
 * These offsets describes the partition tables in the MBR
 */

/* 446@0: Generally unused and zero; but may
 * include IDM Boot Manager menu entry at 8@394
 */

#define PART_ENTRY(n)     (446 + ((n) << 4)) /* n = 0,1,2,3 */

#define PART_ENTRY1        446 /* 16@446: Partition table, first entry */
#define PART_ENTRY2        462 /* 16@462: Partition table, second entry */
#define PART_ENTRY3        478 /* 16@478: Partition table, third entry */
#define PART_ENTRY4        494 /* 16@494: Partition table, fourth entry */
#define PART_SIGNATURE     510 /* 2@510: Valid partitions have 0x55aa here */

/****************************************************************************
 * These offsets describes one partition table entry.  NOTE that ent entries
 * are aligned to 16-bit offsets so that the STARTSECTOR and SIZE values are
 * not properly aligned.
 */

#define PART_BOOTINDICATOR   0  /* 1@0:  Boot indicator (0x80: active;0x00:otherwise) */
#define PART_STARTCHS        1  /* 3@1:  Starting Cylinder/Head/Sector values */
#define PART_TYPE            4  /* 1@4:  Partition type description */
#define PART_ENDCHS          5  /* 3@5:  Ending Cylinder/Head/Sector values */
#define PART_STARTSECTOR     8  /* 4@8:  Starting sector */
#define PART_SIZE           12  /* 4@12: Partition size (in sectors) */

/****************************************************************************
 * Partition table types.
 */

#define PART_TYPE_NONE       0  /* No partition */
#define PART_TYPE_FAT12      1  /* FAT12 */
#define PART_TYPE_FAT16A     4  /* FAT16 (Partition smaller than 32MB) */
#define PART_TYPE_EXT        5  /* Extended MS-DOS Partition */
#define PART_TYPE_FAT16B     6  /* FAT16 (Partition larger than 32MB) */
#define PART_TYPE_FAT32     11  /* FAT32 (Partition up to 2048Gb) */
#define PART_TYPE_FAT32X    12  /* Same as 11, but uses LBA1 0x13 extensions */
#define PART_TYPE_FAT16X    14  /* Same as 6, but uses LBA1 0x13 extensions */
#define PART_TYPE_EXTX      15  /* Same as 5, but uses LBA1 0x13 extensions */

/****************************************************************************
 * Fat Boot Record (FBR).
 *
 * The FBR is always the very first sector in the partition. Validity check
 * is performed by comparing the 16 bit word at offset 1FE to AA55.  The
 * structure of the FBR is shown below.
 *
 * NOTE that the fields of the FBR are equivalent to the MBR.  This fact is
 * explicitly assumed in the function fat_checkbootrecord() which will
 * operate on either an MBR or an FBR.
 */

#define FBR_OEMNAME          3 /*  8@3:  Usually "MSWIN4.1" */
#define FBR_BYTESPERSEC     11 /*  2@11: Bytes per sector: 512, 1024, 2048, 4096  */
#define FBR_SECPERCLUS      13 /*  1@13: Sectors per allocation unit: 2**n, n=0..7 */
#define FBR_RESVDSECCOUNT   14 /*  2@14: Reserved sector count: Usually 32 */
#define FBR_NUMFATS         16 /*  1@16: Number of FAT data structures: always 2 */
#define FBR_ROOTENTCNT      17 /*  2@17: FAT12/16: Must be 0 for FAT32 */
#define FBR_TOTSEC16        19 /*  2@19: FAT12/16: Must be 0, see FBR_TOTSEC32 */
#define FBR_MEDIA           21 /*  1@21: Media code: f0, f8, f9-fa, fc-ff */
#define FBR_FATSZ16         22 /*  2@22: FAT12/16: Must be 0, see FBR_FATSZ32 */
#define FBR_SECPERTRK       24 /*  2@24: Sectors per track geometry value */
#define FBR_NUMHEADS        26 /*  2@26: Number of heads geometry value */
#define FBR_HIDSEC          28 /*  4@28: Count of hidden sectors preceding FAT */
#define FBR_TOTSEC32        32 /*  4@32: Total count of sectors on the volume */
#define FBR_FATSZ32         36 /*  4@36: Count of sectors occupied by one FAT (FAT32) */
#define FBR_EXTFLAGS        40 /*  2@40: Ext Flags */
#define FBR_FSVER           42 /*  2@42: FS Version */
#define FBR_ROOTCLUS        44 /*  4@44: Cluster no. of 1st cluster of root dir */
#define FBR_FSINFO          48 /*  2@48: FS Info Sector */
#define FBR_BKBOOTSEC       50 /*  2@50: Sector number of boot record. Usually 6  */
                               /*  52-301 Reserved */

/* The following fields are only valid for FAT12/16 */

#define FBR16_DRVNUM        36 /*  1@36: Drive number for MS-DOS bootstrap */
                               /*  1@37: Reserved (zero) */
#define FBR16_BOOTSIG       38 /*  1@38: Extended boot signature: 0x29 if following valid */
#define FBR16_VOLID         39 /*  4@39: Volume serial number */
#define FBR16_VOLLAB        43 /* 11@43: Volume label */
#define FBR16_FILESYSTYPE   54 /*  8@54: "FAT12  ", "FAT16  ", or "FAT    " */

/* The following fields are only valid for FAT32 */

#define FBR32_DRVNUM        64 /*  1@64: Drive number for MS-DOS bootstrap */
#define FBR32_BOOTSIG       65 /*  1@65: Extended boot signature: 0x29 if following valid */
#define FBR32_VOLID         66 /*  4@66: Volume serial number */
#define FBR32_VOLLAB        71 /* 11@71: Volume label */
#define FBR32_FILESYSTYPE   82 /*  8@62: "FAT12  ", "FAT16  ", or "FAT    " */

/* The magic bytes at the end of the MBR are common to FAT12/16/32 */

#define FBR_SIGNATURE      510 /*  2@510: Valid MBRs have 0x55aa here */

/****************************************************************************
 * Each FAT "short" 8.3 file name directory entry is 32-bytes long.
 *
 * Sizes and limits
 */

/****************************************************************************
 * Each FAT "short" 8.3 file name directory entry is 32-bytes long.
 *
 * Sizes and limits
 */

#define DIR_MAXFNAME        11  /* Max short name size is 8+3 = 11 */

/* The following define offsets relative to the beginning of a directory
 * entry.
 */

#define DIR_NAME             0 /* 11@ 0: NAME: 8 bytes + 3 byte extension */
#define DIR_ATTRIBUTES      11 /*  1@11: File attributes (see below) */
#define DIR_NTRES           12 /*  1@12: Reserved for use by NT */
#define DIR_CRTTIMETENTH    13 /*  1@13: Tenth sec creation timestamp */
#define DIR_CRTIME          14 /*  2@14: Time file created */
#define DIR_CRDATE          16 /*  2@16: Date file created */
#define DIR_LASTACCDATE     18 /*  2@19: Last access date */
#define DIR_FSTCLUSTHI      20 /*  2@20: MS first cluster number */
#define DIR_WRTTIME         22 /*  2@22: Time of last write */
#define DIR_WRTDATE         24 /*  2@24: Date of last write */
#define DIR_FSTCLUSTLO      26 /*  2@26: LS first cluster number */
#define DIR_FILESIZE        28 /*  4@28: File size in bytes */
#define DIR_SIZE            32 /* The size of one directory entry */
#define DIR_SHIFT            5 /* log2 of DIR_SIZE */

/* First byte of the directory name has special meanings: */

#define DIR0_EMPTY         0xe5 /* The directory entry is empty */
#define DIR0_ALLEMPTY      0x00 /* This entry and all following are empty */
#define DIR0_E5            0x05 /* The actual value is 0xe5 */

/* NTRES flags in the FAT directory */

#define FATNTRES_LCNAME    0x08 /* Lower case in name */
#define FATNTRES_LCEXT     0x10 /* Lower case in extension */

/* Directory indexing helper.  Each directory entry is 32-bytes in length.
 * The number of directory entries in a sector then varies with the size
 * of the sector supported in hardware.
 */

#define DIRSEC_NDXMASK(f)   (((f)->fs_hwsectorsize - 1) >> 5)
#define DIRSEC_NDIRS(f)     (((f)->fs_hwsectorsize) >> 5)
#define DIRSEC_BYTENDX(f,i) (((i) & DIRSEC_NDXMASK(fs)) << 5)

#define SEC_NDXMASK(f)      ((f)->fs_hwsectorsize - 1)
#define SEC_NSECTORS(f,n)   ((n) / (f)->fs_hwsectorsize)

#define CLUS_NDXMASK(f)     ((f)->fs_fatsecperclus - 1)

/* The FAT "long" file name (LFN) directory entry */

#ifdef CONFIG_FAT_LFN

/* Sizes and limits */

# if CONFIG_FAT_MAXFNAME > CONFIG_NAME_MAX && CONFIG_NAME_MAX >= 12
#   warning CONFIG_FAT_MAXFNAME may not exceed NAME_MAX (CONFIG_NAME_MAX)
#   undef  CONFIG_FAT_MAXFNAME
#   define CONFIG_FAT_MAXFNAME CONFIG_NAME_MAX
# endif

# if CONFIG_FAT_MAXFNAME < 12
#   undef  CONFIG_FAT_MAXFNAME
#   define CONFIG_FAT_MAXFNAME 12
# endif

# ifndef CONFIG_FAT_MAXFNAME   /* The maximum support filename can be limited */
#   define LDIR_MAXFNAME   255 /* Max unicode characters in file name */
# elif CONFIG_FAT_MAXFNAME <= 255
#   define LDIR_MAXFNAME  CONFIG_FAT_MAXFNAME
# else
#   error "Illegal value for CONFIG_FAT_MAXFNAME"
# endif

# define LDIR_MAXLFNCHARS   13  /* Max unicode characters in one LFN entry */
# define LDIR_MAXLFNS       20  /* Max number of LFN entries */

/* LFN directory entry offsets */

# define LDIR_SEQ            0  /*  1@ 0: Sequence number */
# define LDIR_WCHAR1_5       1  /* 10@ 1: File name characters 1-5 (5 Unicode characters) */
# define LDIR_ATTRIBUTES    11  /*  1@11: File attributes (always 0x0f) */
# define LDIR_NTRES         12  /*  1@12: Reserved for use by NT  (always 0x00) */
# define LDIR_CHECKSUM      13  /*  1@13: Checksum of the DOS filename */
# define LDIR_WCHAR6_11     14  /* 12@14: File name characters 6-11 (6 Unicode characters) */
# define LDIR_FSTCLUSTLO    26  /*  2@26: First cluster (always 0x0000) */
# define LDIR_WCHAR12_13    28  /*  4@28: File name characters 12-13 (2 Unicode characters) */

/* LFN sequence number and allocation status */

# define LDIR0_EMPTY       DIR0_EMPTY    /* The directory entry is empty */
# define LDIR0_ALLEMPTY    DIR0_ALLEMPTY /* This entry and all following are empty */
# define LDIR0_E5          DIR0_E5       /* The actual value is 0xe5 */
# define LDIR0_LAST        0x40          /* Last LFN in file name (appears first) */
# define LDIR0_SEQ_MASK    0x1f          /* Mask for sequence number (1-20) */

/* The LFN entry attribute */

# define LDDIR_LFNATTR     0x0f
#endif

/* File system types */

#define FSTYPE_FAT12         0
#define FSTYPE_FAT16         1
#define FSTYPE_FAT32         2

/* File buffer flags (ff_bflags) */

#define FFBUFF_VALID         1
#define FFBUFF_DIRTY         2
#define FFBUFF_MODIFIED      4

/* Mount status flags (ff_bflags) */

#define UMOUNT_FORCED        8

/****************************************************************************
 * These offset describe the FSINFO sector
 */

#define FSI_LEADSIG          0 /*   4@0:   0x41615252  = "RRaA" */
                               /* 480@4:   Reserved (zero) */
#define FSI_STRUCTSIG      484 /*   4@484: 0x61417272 = "rrAa" */
#define FSI_FREECOUNT      488 /*   4@488: Last free cluster count on volume */
#define FSI_NXTFREE        492 /*   4@492: Cluster number of 1st free cluster */
                               /*  12@496: Reserved (zero) */
#define FSI_TRAILSIG       508 /*   4@508: 0xaa550000 */

/****************************************************************************
 * FAT values
 */

#define FAT_EOF            0x0ffffff8
#define FAT_BAD            0x0ffffff7

/****************************************************************************
 * Maximum cluster by FAT type.  This is the key value used to distinguish
 * between FAT12, 16, and 32.
 */

/* FAT12: For M$, the calculation is ((1 << 12) - 19).  But we will follow
 * the Linux tradition of allowing slightly more clusters for FAT12.
 */

#define FAT_MAXCLUST12 ((1 << 12) - 16)

/* FAT16: For M$, the calculation is ((1 << 16) - 19). (The uint32_t cast is
 * needed for architectures where int is only 16 bits).
 */

#define FAT_MINCLUST16 (FAT_MAXCLUST12 + 1)
#define FAT_MAXCLUST16 (((uint32_t)1 << 16) - 16)

/* FAT32: M$ reserves the MS 4 bits of a FAT32 FAT entry so only 18 bits are
 * available.  For M$, the calculation is ((1 << 28) - 19). (The uint32_t
 * cast is needed for architectures where int is only 16 bits).  M$ also
 * claims that the minimum size is 65,527.
 */

#define FAT_MINCLUST32  65524
/* #define FAT_MINCLUST32  (FAT_MAXCLUST16 + 1) */
#define FAT_MAXCLUST32  (((uint32_t)1 << 28) - 16)

/* Access to data in raw sector data */

#define UBYTE_VAL(p,o)            (((uint8_t*)(p))[o])
#define UBYTE_PTR(p,o)            &UBYTE_VAL(p,o)
#define UBYTE_PUT(p,o,v)          (UBYTE_VAL(p,o)=(uint8_t)(v))

#define UINT16_PTR(p,o)           ((uint16_t*)UBYTE_PTR(p,o))
#define UINT16_VAL(p,o)           (*UINT16_PTR(p,o))
#define UINT16_PUT(p,o,v)         (UINT16_VAL(p,o)=(uint16_t)(v))

#define UINT32_PTR(p,o)           ((uint32_t*)UBYTE_PTR(p,o))
#define UINT32_VAL(p,o)           (*UINT32_PTR(p,o))
#define UINT32_PUT(p,o,v)         (UINT32_VAL(p,o)=(uint32_t)(v))

/* Regardless of the endian-ness of the target or alignment of the data, no
 * special operations are required for byte, string or byte array accesses.
 * The FAT data stream is little endian so multiple byte values must be
 * accessed byte-by-byte for big-endian targets.
 */

#define MBR_GETSECPERCLUS(p)      UBYTE_VAL(p,MBR_SECPERCLUS)
#define MBR_GETNUMFATS(p)         UBYTE_VAL(p,MBR_NUMFATS)
#define MBR_GETMEDIA(p)           UBYTE_VAL(p,MBR_MEDIA)
#define MBR_GETDRVNUM16(p)        UBYTE_VAL(p,MBR16_DRVNUM)
#define MBR_GETDRVNUM32(p)        UBYTE_VAL(p,MBR32_DRVNUM)
#define MBR_GETBOOTSIG16(p)       UBYTE_VAL(p,MBR16_BOOTSIG)
#define MBR_GETBOOTSIG32(p)       UBYTE_VAL(p,MBR32_BOOTSIG)

#define FBR_GETSECPERCLUS(p)      UBYTE_VAL(p,FBR_SECPERCLUS)
#define FBR_GETNUMFATS(p)         UBYTE_VAL(p,FBR_NUMFATS)
#define FBR_GETMEDIA(p)           UBYTE_VAL(p,FBR_MEDIA)
#define FBR_GETDRVNUM16(p)        UBYTE_VAL(p,FBR16_DRVNUM)
#define FBR_GETDRVNUM32(p)        UBYTE_VAL(p,FBR32_DRVNUM)
#define FBR_GETBOOTSIG16(p)       UBYTE_VAL(p,FBR16_BOOTSIG)
#define FBR_GETBOOTSIG32(p)       UBYTE_VAL(p,FBR32_BOOTSIG)

#define PART_GETTYPE(n,p)         UBYTE_VAL(p,PART_ENTRY(n)+PART_TYPE)
#define PART1_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY1+PART_TYPE)
#define PART2_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY2+PART_TYPE)
#define PART3_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY3+PART_TYPE)
#define PART4_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY4+PART_TYPE)

#define DIR_GETATTRIBUTES(p)      UBYTE_VAL(p,DIR_ATTRIBUTES)
#define DIR_GETNTRES(p)           UBYTE_VAL(p,DIR_NTRES)
#define DIR_GETCRTTIMETENTH(p)    UBYTE_VAL(p,DIR_CRTTIMETENTH)

#ifdef CONFIG_FAT_LFN
# define LDIR_GETSEQ(p)           UBYTE_VAL(p,LDIR_SEQ)
# define LDIR_GETATTRIBUTES(p)    UBYTE_VAL(p,LDIR_ATTRIBUTES)
# define LDIR_GETNTRES(p)         UBYTE_VAL(p,LDIR_NTRES)
# define LDIR_GETCHECKSUM(p)      UBYTE_VAL(p,LDIR_CHECKSUM)
#endif

#define MBR_PUTSECPERCLUS(p,v)    UBYTE_PUT(p,MBR_SECPERCLUS,v)
#define MBR_PUTNUMFATS(p,v)       UBYTE_PUT(p,MBR_NUMFATS,v)
#define MBR_PUTMEDIA(p,v)         UBYTE_PUT(p,MBR_MEDIA,v)
#define MBR_PUTDRVNUM16(p,v)      UBYTE_PUT(p,MBR16_DRVNUM,v)
#define MBR_PUTDRVNUM32(p,v)      UBYTE_PUT(p,MBR32_DRVNUM,v)
#define MBR_PUTBOOTSIG16(p,v)     UBYTE_PUT(p,MBR16_BOOTSIG,v)
#define MBR_PUTBOOTSIG32(p,v)     UBYTE_PUT(p,MBR32_BOOTSIG,v)

#define FBR_PUTSECPERCLUS(p,v)    UBYTE_PUT(p,FBR_SECPERCLUS,v)
#define FBR_PUTNUMFATS(p,v)       UBYTE_PUT(p,FBR_NUMFATS,v)
#define FBR_PUTMEDIA(p,v)         UBYTE_PUT(p,FBR_MEDIA,v)
#define FBR_PUTDRVNUM16(p,v)      UBYTE_PUT(p,FBR16_DRVNUM,v)
#define FBR_PUTDRVNUM32(p,v)      UBYTE_PUT(p,FBR32_DRVNUM,v)
#define FBR_PUTBOOTSIG16(p,v)     UBYTE_PUT(p,FBR16_BOOTSIG,v)
#define FBR_PUTBOOTSIG32(p,v)     UBYTE_PUT(p,FBR32_BOOTSIG,v)

#define PART_PUTTYPE(n,p,v)       UBYTE_PUT(p,PART_ENTRY(n)+PART_TYPE,v)
#define PART1_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY1+PART_TYPE,v)
#define PART2_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY2+PART_TYPE,v)
#define PART3_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY3+PART_TYPE,v)
#define PART4_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY4+PART_TYPE,v)

#define DIR_PUTATTRIBUTES(p,v)    UBYTE_PUT(p,DIR_ATTRIBUTES,v)
#define DIR_PUTNTRES(p,v)         UBYTE_PUT(p,DIR_NTRES,v)
#define DIR_PUTCRTTIMETENTH(p,v)  UBYTE_PUT(p,DIR_CRTTIMETENTH,v)

#ifdef CONFIG_FAT_LFN
# define LDIR_PUTSEQ(p,v)         UBYTE_PUT(p,LDIR_SEQ,v)
# define LDIR_PUTATTRIBUTES(p,v)  UBYTE_PUT(p,LDIR_ATTRIBUTES,v)
# define LDIR_PUTNTRES(p,v)       UBYTE_PUT(p,LDIR_NTRES,v)
# define LDIR_PUTCHECKSUM(p,v)    UBYTE_PUT(p,LDIR_CHECKSUM,v)
#endif

/* For the all targets, unaligned values need to be accessed byte-by-byte.
 * Some architectures may handle unaligned accesses with special interrupt
 * handlers.  But even in that case, it is more efficient to avoid the traps.
 */

/* Unaligned multi-byte access macros */

#define MBR_GETBYTESPERSEC(p)      fat_getuint16(UBYTE_PTR(p,MBR_BYTESPERSEC))
#define MBR_GETROOTENTCNT(p)       fat_getuint16(UBYTE_PTR(p,MBR_ROOTENTCNT))
#define MBR_GETTOTSEC16(p)         fat_getuint16(UBYTE_PTR(p,MBR_TOTSEC16))
#define MBR_GETVOLID16(p)          fat_getuint32(UBYTE_PTR(p,MBR16_VOLID))
#define MBR_GETVOLID32(p)          fat_getuint32(UBYTE_PTR(p,MBR32_VOLID))

#define FBR_GETBYTESPERSEC(p)      fat_getuint16(UBYTE_PTR(p,FBR_BYTESPERSEC))
#define FBR_GETROOTENTCNT(p)       fat_getuint16(UBYTE_PTR(p,FBR_ROOTENTCNT))
#define FBR_GETTOTSEC16(p)         fat_getuint16(UBYTE_PTR(p,FBR_TOTSEC16))
#define FBR_GETVOLID16(p)          fat_getuint32(UBYTE_PTR(p,FBR16_VOLID))
#define FBR_GETVOLID32(p)          fat_getuint32(UBYTE_PTR(p,FBR32_VOLID))

#define PART_GETSTARTSECTOR(n,p)   fat_getuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_STARTSECTOR))
#define PART_GETSIZE(n,p)          fat_getuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_SIZE))
#define PART1_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY1+PART_STARTSECTOR))
#define PART1_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY1+PART_SIZE))
#define PART2_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY2+PART_STARTSECTOR))
#define PART2_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY2+PART_SIZE))
#define PART3_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY3+PART_STARTSECTOR))
#define PART3_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY3+PART_SIZE))
#define PART4_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY4+PART_STARTSECTOR))
#define PART4_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY4+PART_SIZE))

#define MBR_PUTBYTESPERSEC(p,v)    fat_putuint16(UBYTE_PTR(p,MBR_BYTESPERSEC),v)
#define MBR_PUTROOTENTCNT(p,v)     fat_putuint16(UBYTE_PTR(p,MBR_ROOTENTCNT),v)
#define MBR_PUTTOTSEC16(p,v)       fat_putuint16(UBYTE_PTR(p,MBR_TOTSEC16),v)
#define MBR_PUTVOLID16(p,v)        fat_putuint32(UBYTE_PTR(p,MBR16_VOLID),v)
#define MBR_PUTVOLID32(p,v)        fat_putuint32(UBYTE_PTR(p,MBR32_VOLID),v)

#define FBR_PUTBYTESPERSEC(p,v)    fat_putuint16(UBYTE_PTR(p,FBR_BYTESPERSEC),v)
#define FBR_PUTROOTENTCNT(p,v)     fat_putuint16(UBYTE_PTR(p,FBR_ROOTENTCNT),v)
#define FBR_PUTTOTSEC16(p,v)       fat_putuint16(UBYTE_PTR(p,FBR_TOTSEC16),v)
#define FBR_PUTVOLID16(p,v)        fat_putuint32(UBYTE_PTR(p,FBR16_VOLID),v)
#define FBR_PUTVOLID32(p,v)        fat_putuint32(UBYTE_PTR(p,FBR32_VOLID),v)

#define PART_PUTSTARTSECTOR(n,p,v) fat_putuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_STARTSECTOR),v)
#define PART_PUTSIZE(n,p,v)        fat_putuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_SIZE),v)
#define PART1_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY1+PART_STARTSECTOR),v)
#define PART1_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY1+PART_SIZE),v)
#define PART2_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY2+PART_STARTSECTOR),v)
#define PART2_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY2+PART_SIZE),v)
#define PART3_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY3+PART_STARTSECTOR),v)
#define PART3_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY3+PART_SIZE),v)
#define PART4_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY4+PART_STARTSECTOR),v)
#define PART4_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY4+PART_SIZE),v)

#ifdef CONFIG_FAT_LFN
# define LDIR_PTRWCHAR1_5(p)       UBYTE_PTR(p,LDIR_WCHAR1_5)
# define LDIR_PTRWCHAR6_11(p)      UBYTE_PTR(p,LDIR_WCHAR6_11)
# define LDIR_PTRWCHAR12_13(p)     UBYTE_PTR(p,LDIR_WCHAR12_13)
#endif

/* But for multi-byte values, the endian-ness of the target vs. the little
 * endian order of the byte stream or alignment of the data within the byte
 * stream can force special, byte-by-byte accesses.
 */

#ifdef CONFIG_ENDIAN_BIG

/* If the target is big-endian, then even aligned multi-byte values must be
 * accessed byte-by-byte.
 */

# define MBR_GETRESVDSECCOUNT(p)   fat_getuint16(UBYTE_PTR(p,MBR_RESVDSECCOUNT))
# define MBR_GETFATSZ16(p)         fat_getuint16(UBYTE_PTR(p,MBR_FATSZ16))
# define MBR_GETSECPERTRK(p)       fat_getuint16(UBYTE_PTR(p,MBR_SECPERTRK))
# define MBR_GETNUMHEADS(p)        fat_getuint16(UBYTE_PTR(p,MBR_NUMHEADS))
# define MBR_GETHIDSEC(p)          fat_getuint32(UBYTE_PTR(p,MBR_HIDSEC))
# define MBR_GETTOTSEC32(p)        fat_getuint32(UBYTE_PTR(p,MBR_TOTSEC32))
# define MBR_GETFATSZ32(p)         fat_getuint32(UBYTE_PTR(p,MBR32_FATSZ32))
# define MBR_GETEXTFLAGS(p)        fat_getuint16(UBYTE_PTR(p,MBR32_EXTFLAGS))
# define MBR_GETFSVER(p)           fat_getuint16(UBYTE_PTR(p,MBR32_FSVER))
# define MBR_GETROOTCLUS(p)        fat_getuint32(UBYTE_PTR(p,MBR32_ROOTCLUS))
# define MBR_GETFSINFO(p)          fat_getuint16(UBYTE_PTR(p,MBR32_FSINFO))
# define MBR_GETBKBOOTSEC(p)       fat_getuint16(UBYTE_PTR(p,MBR32_BKBOOTSEC))
# define MBR_GETSIGNATURE(p)       fat_getuint16(UBYTE_PTR(p,MBR_SIGNATURE))

# define FBR_GETRESVDSECCOUNT(p)   fat_getuint16(UBYTE_PTR(p,FBR_RESVDSECCOUNT))
# define FBR_GETFATSZ16(p)         fat_getuint16(UBYTE_PTR(p,FBR_FATSZ16))
# define FBR_GETSECPERTRK(p)       fat_getuint16(UBYTE_PTR(p,FBR_SECPERTRK))
# define FBR_GETNUMHEADS(p)        fat_getuint16(UBYTE_PTR(p,FBR_NUMHEADS))
# define FBR_GETHIDSEC(p)          fat_getuint32(UBYTE_PTR(p,FBR_HIDSEC))
# define FBR_GETTOTSEC32(p)        fat_getuint32(UBYTE_PTR(p,FBR_TOTSEC32))
# define FBR_GETFATSZ32(p)         fat_getuint32(UBYTE_PTR(p,FBR_FATSZ32))
# define FBR_GETEXTFLAGS(p)        fat_getuint16(UBYTE_PTR(p,FBR_EXTFLAGS))
# define FBR_GETFSVER(p)           fat_getuint16(UBYTE_PTR(p,FBR_FSVER))
# define FBR_GETROOTCLUS(p)        fat_getuint32(UBYTE_PTR(p,FBR_ROOTCLUS))
# define FBR_GETFSINFO(p)          fat_getuint16(UBYTE_PTR(p,FBR_FSINFO))
# define FBR_GETBKBOOTSEC(p)       fat_getuint16(UBYTE_PTR(p,FBR_BKBOOTSEC))
# define FBR_GETSIGNATURE(p)       fat_getuint16(UBYTE_PTR(p,FBR_SIGNATURE))

# define FSI_GETLEADSIG(p)         fat_getuint32(UBYTE_PTR(p,FSI_LEADSIG))
# define FSI_GETSTRUCTSIG(p)       fat_getuint32(UBYTE_PTR(p,FSI_STRUCTSIG))
# define FSI_GETFREECOUNT(p)       fat_getuint32(UBYTE_PTR(p,FSI_FREECOUNT))
# define FSI_GETNXTFREE(p)         fat_getuint32(UBYTE_PTR(p,FSI_NXTFREE))
# define FSI_GETTRAILSIG(p)        fat_getuint32(UBYTE_PTR(p,FSI_TRAILSIG))

# define DIR_GETCRTIME(p)          fat_getuint16(UBYTE_PTR(p,DIR_CRTIME))
# define DIR_GETCRDATE(p)          fat_getuint16(UBYTE_PTR(p,DIR_CRDATE))
# define DIR_GETLASTACCDATE(p)     fat_getuint16(UBYTE_PTR(p,DIR_LASTACCDATE))
# define DIR_GETFSTCLUSTHI(p)      fat_getuint16(UBYTE_PTR(p,DIR_FSTCLUSTHI))
# define DIR_GETWRTTIME(p)         fat_getuint16(UBYTE_PTR(p,DIR_WRTTIME))
# define DIR_GETWRTDATE(p)         fat_getuint16(UBYTE_PTR(p,DIR_WRTDATE))
# define DIR_GETFSTCLUSTLO(p)      fat_getuint16(UBYTE_PTR(p,DIR_FSTCLUSTLO))
# define DIR_GETFILESIZE(p)        fat_getuint32(UBYTE_PTR(p,DIR_FILESIZE))

# ifdef CONFIG_FAT_LFN
#  define LDIR_GETWCHAR1(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR1_5))
#  define LDIR_GETWCHAR2(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+2))
#  define LDIR_GETWCHAR3(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+4))
#  define LDIR_GETWCHAR4(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+6))
#  define LDIR_GETWCHAR5(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+8))
#  define LDIR_GETWCHAR6(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11))
#  define LDIR_GETWCHAR7(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+2))
#  define LDIR_GETWCHAR8(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+4))
#  define LDIR_GETWCHAR9(p)        fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+6))
#  define LDIR_GETWCHAR10(p)       fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+8))
#  define LDIR_GETWCHAR11(p)       fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+10))
#  define LDIR_GETWCHAR12(p)       fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR12_13))
#  define LDIR_GETWCHAR13(p)       fat_getuint16(UBYTE_PTR(p,LDIR_WCHAR12_13+2))
#  define LDIR_GETFSTCLUSTLO(p)    fat_getuint16(UBYTE_PTR(p,LDIR_FSTCLUSTLO))
# endif

# define FSI_GETLEADSIG(p)         fat_getuint32(UBYTE_PTR(p,FSI_LEADSIG))
# define FSI_GETSTRUCTSIG(p)       fat_getuint32(UBYTE_PTR(p,FSI_STRUCTSIG))
# define FSI_GETFREECOUNT(p)       fat_getuint32(UBYTE_PTR(p,FSI_FREECOUNT))
# define FSI_GETNXTFREE(p)         fat_getuint32(UBYTE_PTR(p,FSI_NXTFREE))
# define FSI_GETTRAILSIG(p)        fat_getuint32(UBYTE_PTR(p,FSI_TRAILSIG))

# define FAT_GETFAT16(p,i)         fat_getuint16(UBYTE_PTR(p,i))
# define FAT_GETFAT32(p,i)         fat_getuint32(UBYTE_PTR(p,i))

# define MBR_PUTRESVDSECCOUNT(p,v) fat_putuint16(UBYTE_PTR(p,MBR_RESVDSECCOUNT),v)
# define MBR_PUTFATSZ16(p,v)       fat_putuint16(UBYTE_PTR(p,MBR_FATSZ16),v)
# define MBR_PUTSECPERTRK(p,v)     fat_putuint16(UBYTE_PTR(p,MBR_SECPERTRK),v)
# define MBR_PUTNUMHEADS(p,v)      fat_putuint16(UBYTE_PTR(p,MBR_NUMHEADS),v)
# define MBR_PUTHIDSEC(p,v)        fat_putuint32(UBYTE_PTR(p,MBR_HIDSEC),v)
# define MBR_PUTTOTSEC32(p,v)      fat_putuint32(UBYTE_PTR(p,MBR_TOTSEC32),v)
# define MBR_PUTFATSZ32(p,v)       fat_putuint32(UBYTE_PTR(p,MBR32_FATSZ32),v)
# define MBR_PUTEXTFLAGS(p,v)      fat_putuint16(UBYTE_PTR(p,MBR32_EXTFLAGS),v)
# define MBR_PUTFSVER(p,v)         fat_putuint16(UBYTE_PTR(p,MBR32_FSVER),v)
# define MBR_PUTROOTCLUS(p,v)      fat_putuint32(UBYTE_PTR(p,MBR32_ROOTCLUS),v)
# define MBR_PUTFSINFO(p,v)        fat_putuint16(UBYTE_PTR(p,MBR32_FSINFO),v)
# define MBR_PUTBKBOOTSEC(p,v)     fat_putuint16(UBYTE_PTR(p,MBR32_BKBOOTSEC),v)
# define MBR_PUTSIGNATURE(p,v)     fat_putuint16(UBYTE_PTR(p,MBR_SIGNATURE),v)

# define FBR_PUTRESVDSECCOUNT(p,v) fat_putuint16(UBYTE_PTR(p,FBR_RESVDSECCOUNT),v)
# define FBR_PUTFATSZ16(p,v)       fat_putuint16(UBYTE_PTR(p,FBR_FATSZ16),v)
# define FBR_PUTSECPERTRK(p,v)     fat_putuint16(UBYTE_PTR(p,FBR_SECPERTRK),v)
# define FBR_PUTNUMHEADS(p,v)      fat_putuint16(UBYTE_PTR(p,FBR_NUMHEADS),v)
# define FBR_PUTHIDSEC(p,v)        fat_putuint32(UBYTE_PTR(p,FBR_HIDSEC),v)
# define FBR_PUTTOTSEC32(p,v)      fat_putuint32(UBYTE_PTR(p,FBR_TOTSEC32),v)
# define FBR_PUTFATSZ32(p,v)       fat_putuint32(UBYTE_PTR(p,FBR_FATSZ32),v)
# define FBR_PUTEXTFLAGS(p,v)      fat_putuint16(UBYTE_PTR(p,FBR_EXTFLAGS),v)
# define FBR_PUTFSVER(p,v)         fat_putuint16(UBYTE_PTR(p,FBR_FSVER),v)
# define FBR_PUTROOTCLUS(p,v)      fat_putuint32(UBYTE_PTR(p,FBR_ROOTCLUS),v)
# define FBR_PUTFSINFO(p,v)        fat_putuint16(UBYTE_PTR(p,FBR_FSINFO),v)
# define FBR_PUTBKBOOTSEC(p,v)     fat_putuint16(UBYTE_PTR(p,FBR_BKBOOTSEC),v)
# define FBR_PUTSIGNATURE(p,v)     fat_putuint16(UBYTE_PTR(p,FBR_SIGNATURE),v)

# define FSI_PUTLEADSIG(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_LEADSIG),v)
# define FSI_PUTSTRUCTSIG(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_STRUCTSIG),v)
# define FSI_PUTFREECOUNT(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_FREECOUNT),v)
# define FSI_PUTNXTFREE(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_NXTFREE),v)
# define FSI_PUTTRAILSIG(p,v)      fat_putuint32(UBYTE_PTR(p,FSI_TRAILSIG),v)

# define DIR_PUTCRTIME(p,v)        fat_putuint16(UBYTE_PTR(p,DIR_CRTIME),v)
# define DIR_PUTCRDATE(p,v)        fat_putuint16(UBYTE_PTR(p,DIR_CRDATE),v)
# define DIR_PUTLASTACCDATE(p,v)   fat_putuint16(UBYTE_PTR(p,DIR_LASTACCDATE),v)
# define DIR_PUTFSTCLUSTHI(p,v)    fat_putuint16(UBYTE_PTR(p,DIR_FSTCLUSTHI),v)
# define DIR_PUTWRTTIME(p,v)       fat_putuint16(UBYTE_PTR(p,DIR_WRTTIME),v)
# define DIR_PUTWRTDATE(p,v)       fat_putuint16(UBYTE_PTR(p,DIR_WRTDATE),v)
# define DIR_PUTFSTCLUSTLO(p,v)    fat_putuint16(UBYTE_PTR(p,DIR_FSTCLUSTLO),v)
# define DIR_PUTFILESIZE(p,v)      fat_putuint32(UBYTE_PTR(p,DIR_FILESIZE),v)

# ifdef CONFIG_FAT_LFN
#  define LDIR_PUTWCHAR1(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR1_5),v)
#  define LDIR_PUTWCHAR2(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+2),v)
#  define LDIR_PUTWCHAR3(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+4),v)
#  define LDIR_PUTWCHAR4(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+6),v)
#  define LDIR_PUTWCHAR5(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR1_5+8),v)
#  define LDIR_PUTWCHAR6(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11),v)
#  define LDIR_PUTWCHAR7(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+2),v)
#  define LDIR_PUTWCHAR8(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+4),v)
#  define LDIR_PUTWCHAR9(p,v)      fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+6),v)
#  define LDIR_PUTWCHAR10(p,v)     fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+8),v)
#  define LDIR_PUTWCHAR11(p,v)     fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR6_11+10),v)
#  define LDIR_PUTWCHAR12(p,v)     fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR12_13),v)
#  define LDIR_PUTWCHAR13(p,v)     fat_putuint16(UBYTE_PTR(p,LDIR_WCHAR12_13+2),v)
#  define LDIR_PUTFSTCLUSTLO(p,v)  fat_putuint16(UBYTE_PTR(p,LDIR_FSTCLUSTLO),v)
# endif

# define FSI_PUTLEADSIG(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_LEADSIG),v)
# define FSI_PUTSTRUCTSIG(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_STRUCTSIG),v)
# define FSI_PUTFREECOUNT(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_FREECOUNT),v)
# define FSI_PUTNXTFREE(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_NXTFREE),v)
# define FSI_PUTTRAILSIG(p,v)      fat_putuint32(UBYTE_PTR(p,FSI_TRAILSIG),v)

# define FAT_PUTFAT16(p,i,v)       fat_putuint16(UBYTE_PTR(p,i),v)
# define FAT_PUTFAT32(p,i,v)       fat_putuint32(UBYTE_PTR(p,i),v)

#else

/* But nothing special has to be done for the little endian-case for access
 * to aligned multibyte values.
 */

# define MBR_GETRESVDSECCOUNT(p)   UINT16_VAL(p,MBR_RESVDSECCOUNT)
# define MBR_GETFATSZ16(p)         UINT16_VAL(p,MBR_FATSZ16)
# define MBR_GETSECPERTRK(p)       UINT16_VAL(p,MBR_SECPERTRK)
# define MBR_GETNUMHEADS(p)        UINT16_VAL(p,MBR_NUMHEADS)
# define MBR_GETHIDSEC(p)          UINT32_VAL(p,MBR_HIDSEC)
# define MBR_GETTOTSEC32(p)        UINT32_VAL(p,MBR_TOTSEC32)
# define MBR_GETFATSZ32(p)         UINT32_VAL(p,MBR32_FATSZ32)
# define MBR_GETEXTFLAGS(p)        UINT16_VAL(p,MBR32_EXTFLAGS)
# define MBR_GETFSVER(p)           UINT16_VAL(p,MBR32_FSVER)
# define MBR_GETROOTCLUS(p)        UINT32_VAL(p,MBR32_ROOTCLUS)
# define MBR_GETFSINFO(p)          UINT16_VAL(p,MBR32_FSINFO)
# define MBR_GETBKBOOTSEC(p)       UINT16_VAL(p,MBR32_BKBOOTSEC)
# define MBR_GETSIGNATURE(p)       UINT16_VAL(p,MBR_SIGNATURE)

# define FBR_GETRESVDSECCOUNT(p)   UINT16_VAL(p,FBR_RESVDSECCOUNT)
# define FBR_GETFATSZ16(p)         UINT16_VAL(p,FBR_FATSZ16)
# define FBR_GETSECPERTRK(p)       UINT16_VAL(p,FBR_SECPERTRK)
# define FBR_GETNUMHEADS(p)        UINT16_VAL(p,FBR_NUMHEADS)
# define FBR_GETHIDSEC(p)          UINT32_VAL(p,FBR_HIDSEC)
# define FBR_GETTOTSEC32(p)        UINT32_VAL(p,FBR_TOTSEC32)
# define FBR_GETFATSZ32(p)         UINT32_VAL(p,FBR_FATSZ32)
# define FBR_GETEXTFLAGS(p)        UINT16_VAL(p,FBR_EXTFLAGS)
# define FBR_GETFSVER(p)           UINT16_VAL(p,FBR_FSVER)
# define FBR_GETROOTCLUS(p)        UINT32_VAL(p,FBR_ROOTCLUS)
# define FBR_GETFSINFO(p)          UINT16_VAL(p,FBR_FSINFO)
# define FBR_GETBKBOOTSEC(p)       UINT16_VAL(p,FBR_BKBOOTSEC)
# define FBR_GETSIGNATURE(p)       UINT16_VAL(p,FBR_SIGNATURE)

# define FSI_GETLEADSIG(p)         UINT32_VAL(p,FSI_LEADSIG)
# define FSI_GETSTRUCTSIG(p)       UINT32_VAL(p,FSI_STRUCTSIG)
# define FSI_GETFREECOUNT(p)       UINT32_VAL(p,FSI_FREECOUNT)
# define FSI_GETNXTFREE(p)         UINT32_VAL(p,FSI_NXTFREE)
# define FSI_GETTRAILSIG(p)        UINT32_VAL(p,FSI_TRAILSIG)

# define DIR_GETCRTIME(p)          UINT16_VAL(p,DIR_CRTIME)
# define DIR_GETCRDATE(p)          UINT16_VAL(p,DIR_CRDATE)
# define DIR_GETLASTACCDATE(p)     UINT16_VAL(p,DIR_LASTACCDATE)
# define DIR_GETFSTCLUSTHI(p)      UINT16_VAL(p,DIR_FSTCLUSTHI)
# define DIR_GETWRTTIME(p)         UINT16_VAL(p,DIR_WRTTIME)
# define DIR_GETWRTDATE(p)         UINT16_VAL(p,DIR_WRTDATE)
# define DIR_GETFSTCLUSTLO(p)      UINT16_VAL(p,DIR_FSTCLUSTLO)
# define DIR_GETFILESIZE(p)        UINT32_VAL(p,DIR_FILESIZE)

# ifdef CONFIG_FAT_LFN
#  define LDIR_GETWCHAR1(p)        UINT16_VAL(p,LDIR_WCHAR1_5)
#  define LDIR_GETWCHAR2(p)        UINT16_VAL(p,LDIR_WCHAR1_5+2)
#  define LDIR_GETWCHAR3(p)        UINT16_VAL(p,LDIR_WCHAR1_5+4)
#  define LDIR_GETWCHAR4(p)        UINT16_VAL(p,LDIR_WCHAR1_5+6)
#  define LDIR_GETWCHAR5(p)        UINT16_VAL(p,LDIR_WCHAR1_5+8)
#  define LDIR_GETWCHAR6(p)        UINT16_VAL(p,LDIR_WCHAR6_11)
#  define LDIR_GETWCHAR7(p)        UINT16_VAL(p,LDIR_WCHAR6_11+2)
#  define LDIR_GETWCHAR8(p)        UINT16_VAL(p,LDIR_WCHAR6_11+4)
#  define LDIR_GETWCHAR9(p)        UINT16_VAL(p,LDIR_WCHAR6_11+6)
#  define LDIR_GETWCHAR10(p)       UINT16_VAL(p,LDIR_WCHAR6_11+8)
#  define LDIR_GETWCHAR11(p)       UINT16_VAL(p,LDIR_WCHAR6_11+10)
#  define LDIR_GETWCHAR12(p)       UINT16_VAL(p,LDIR_WCHAR12_13)
#  define LDIR_GETWCHAR13(p)       UINT16_VAL(p,LDIR_WCHAR12_13+2)
# endif

# define FSI_GETLEADSIG(p)         UINT32_VAL(p,FSI_LEADSIG)
# define FSI_GETSTRUCTSIG(p)       UINT32_VAL(p,FSI_STRUCTSIG)
# define FSI_GETFREECOUNT(p)       UINT32_VAL(p,FSI_FREECOUNT)
# define FSI_GETNXTFREE(p)         UINT32_VAL(p,FSI_NXTFREE)
# define FSI_GETTRAILSIG(p)        UINT32_VAL(p,FSI_TRAILSIG)

# define FAT_GETFAT16(p,i)         UINT16_VAL(p,i)
# define FAT_GETFAT32(p,i)         UINT32_VAL(p,i)

# define MBR_PUTRESVDSECCOUNT(p,v) UINT16_PUT(p,MBR_RESVDSECCOUNT,v)
# define MBR_PUTFATSZ16(p,v)       UINT16_PUT(p,MBR_FATSZ16,v)
# define MBR_PUTSECPERTRK(p,v)     UINT16_PUT(p,MBR_SECPERTRK,v)
# define MBR_PUTNUMHEADS(p,v)      UINT16_PUT(p,MBR_NUMHEADS,v)
# define MBR_PUTHIDSEC(p,v)        UINT32_PUT(p,MBR_HIDSEC,v)
# define MBR_PUTTOTSEC32(p,v)      UINT32_PUT(p,MBR_TOTSEC32,v)
# define MBR_PUTFATSZ32(p,v)       UINT32_PUT(p,MBR32_FATSZ32,v)
# define MBR_PUTEXTFLAGS(p,v)      UINT16_PUT(p,MBR32_EXTFLAGS,v)
# define MBR_PUTFSVER(p,v)         UINT16_PUT(p,MBR32_FSVER,v)
# define MBR_PUTROOTCLUS(p,v)      UINT32_PUT(p,MBR32_ROOTCLUS,v)
# define MBR_PUTFSINFO(p,v)        UINT16_PUT(p,MBR32_FSINFO,v)
# define MBR_PUTBKBOOTSEC(p,v)     UINT16_PUT(p,MBR32_BKBOOTSEC,v)
# define MBR_PUTSIGNATURE(p,v)     UINT16_PUT(p,MBR_SIGNATURE,v)

# define FBR_PUTRESVDSECCOUNT(p,v) UINT16_PUT(p,FBR_RESVDSECCOUNT,v)
# define FBR_PUTFATSZ16(p,v)       UINT16_PUT(p,FBR_FATSZ16,v)
# define FBR_PUTSECPERTRK(p,v)     UINT16_PUT(p,FBR_SECPERTRK,v)
# define FBR_PUTNUMHEADS(p,v)      UINT16_PUT(p,FBR_NUMHEADS,v)
# define FBR_PUTHIDSEC(p,v)        UINT32_PUT(p,FBR_HIDSEC,v)
# define FBR_PUTTOTSEC32(p,v)      UINT32_PUT(p,FBR_TOTSEC32,v)
# define FBR_PUTFATSZ32(p,v)       UINT32_PUT(p,FBR_FATSZ32,v)
# define FBR_PUTEXTFLAGS(p,v)      UINT16_PUT(p,FBR_EXTFLAGS,v)
# define FBR_PUTFSVER(p,v)         UINT16_PUT(p,FBR_FSVER,v)
# define FBR_PUTROOTCLUS(p,v)      UINT32_PUT(p,FBR_ROOTCLUS,v)
# define FBR_PUTFSINFO(p,v)        UINT16_PUT(p,FBR_FSINFO,v)
# define FBR_PUTBKBOOTSEC(p,v)     UINT16_PUT(p,FBR_BKBOOTSEC,v)
# define FBR_PUTSIGNATURE(p,v)     UINT16_PUT(p,FBR_SIGNATURE,v)

# define FSI_PUTLEADSIG(p,v)       UINT32_PUT(p,FSI_LEADSIG,v)
# define FSI_PUTSTRUCTSIG(p,v)     UINT32_PUT(p,FSI_STRUCTSIG,v)
# define FSI_PUTFREECOUNT(p,v)     UINT32_PUT(p,FSI_FREECOUNT,v)
# define FSI_PUTNXTFREE(p,v)       UINT32_PUT(p,FSI_NXTFREE,v)
# define FSI_PUTTRAILSIG(p,v)      UINT32_PUT(p,FSI_TRAILSIG,v)

# define DIR_PUTCRTIME(p,v)        UINT16_PUT(p,DIR_CRTIME,v)
# define DIR_PUTCRDATE(p,v)        UINT16_PUT(p,DIR_CRDATE,v)
# define DIR_PUTLASTACCDATE(p,v)   UINT16_PUT(p,DIR_LASTACCDATE,v)
# define DIR_PUTFSTCLUSTHI(p,v)    UINT16_PUT(p,DIR_FSTCLUSTHI,v)
# define DIR_PUTWRTTIME(p,v)       UINT16_PUT(p,DIR_WRTTIME,v)
# define DIR_PUTWRTDATE(p,v)       UINT16_PUT(p,DIR_WRTDATE,v)
# define DIR_PUTFSTCLUSTLO(p,v)    UINT16_PUT(p,DIR_FSTCLUSTLO,v)
# define DIR_PUTFILESIZE(p,v)      UINT32_PUT(p,DIR_FILESIZE,v)

# ifdef CONFIG_FAT_LFN
#  define LDIR_PUTWCHAR1(p,v)      UINT16_PUT(p,LDIR_WCHAR1_5,v)
#  define LDIR_PUTWCHAR2(p,v)      UINT16_PUT(p,LDIR_WCHAR1_5+2,v)
#  define LDIR_PUTWCHAR3(p,v)      UINT16_PUT(p,LDIR_WCHAR1_5+4,v)
#  define LDIR_PUTWCHAR4(p,v)      UINT16_PUT(p,LDIR_WCHAR1_5+6,v)
#  define LDIR_PUTWCHAR5(p,v)      UINT16_PUT(p,LDIR_WCHAR1_5+8,v)
#  define LDIR_PUTWCHAR6(p,v)      UINT16_PUT(p,LDIR_WCHAR6_11,v)
#  define LDIR_PUTWCHAR7(p,v)      UINT16_PUT(p,LDIR_WCHAR6_11+2,v)
#  define LDIR_PUTWCHAR8(p,v)      UINT16_PUT(p,LDIR_WCHAR6_11+4,v)
#  define LDIR_PUTWCHAR9(p,v)      UINT16_PUT(p,LDIR_WCHAR6_11+6,v)
#  define LDIR_PUTWCHAR10(p,v)     UINT16_PUT(p,LDIR_WCHAR6_11+8,v)
#  define LDIR_PUTWCHAR11(p,v)     UINT16_PUT(p,LDIR_WCHAR6_11+10,v)
#  define LDIR_PUTWCHAR12(p,v)     UINT16_PUT(p,LDIR_WCHAR12_13,v)
#  define LDIR_PUTWCHAR13(p,v)     UINT16_PUT(p,LDIR_WCHAR12_13+2,v)
#  define LDIR_PUTFSTCLUSTLO(p,v)  UINT16_PUT(p,LDIR_FSTCLUSTLO,v)
# endif

# define FSI_PUTLEADSIG(p,v)       UINT32_PUT(p,FSI_LEADSIG,v)
# define FSI_PUTSTRUCTSIG(p,v)     UINT32_PUT(p,FSI_STRUCTSIG,v)
# define FSI_PUTFREECOUNT(p,v)     UINT32_PUT(p,FSI_FREECOUNT,v)
# define FSI_PUTNXTFREE(p,v)       UINT32_PUT(p,FSI_NXTFREE,v)
# define FSI_PUTTRAILSIG(p,v)      UINT32_PUT(p,FSI_TRAILSIG,v)

# define FAT_PUTFAT16(p,i,v)       UINT16_PUT(p,i,v)
# define FAT_PUTFAT32(p,i,v)       UINT32_PUT(p,i,v)

#endif

/****************************************************************************
 * Name: fat_io_alloc and fat_io_free
 *
 * Description:
 *   The FAT file system allocates two I/O buffers for data transfer, each
 *   are the size of one device sector.  One of the buffers is allocated
 *   once for each FAT volume that is mounted; the other buffers are
 *   allocated each time a FAT file is opened.
 *
 *   Some hardware, however, may require special DMA-capable memory in
 *   order to perform the transfers.  If CONFIG_FAT_DMAMEMORY is defined
 *   then the architecture-specific hardware must provide the functions
 *   fat_dma_alloc() and fat_dma_free() as prototyped below:  fat_dmalloc()
 *   will allocate DMA-capable memory of the specified size; fat_dmafree()
 *   is the corresponding function that will be called to free the DMA-
 *   capable memory.
 *
 ****************************************************************************/

#ifdef CONFIG_FAT_DMAMEMORY
#  define fat_io_alloc(s)  fat_dma_alloc(s)
#  define fat_io_free(m,s) fat_dma_free(m,s)
#else
#  define fat_io_alloc(s)  kmm_malloc(s)
#  define fat_io_free(m,s) kmm_free(m)
#endif

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

/* 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 fat32 filesystem.
 */

struct fat_file_s;
struct fat_mountpt_s
{
  struct inode      *fs_blkdriver; /* The block driver inode that hosts the FAT32 fs */
  struct fat_file_s *fs_head;      /* A list to all files opened on this mountpoint */

  sem_t    fs_sem;                 /* Used to assume thread-safe access */
  off_t    fs_hwsectorsize;        /* HW: Sector size reported by block driver */
  off_t    fs_hwnsectors;          /* HW: The number of sectors reported by the hardware */
  off_t    fs_fatbase;             /* Logical block of start of filesystem (past resd sectors) */
  off_t    fs_rootbase;            /* MBR: Cluster no. of 1st cluster of root dir */
  off_t    fs_database;            /* Logical block of start data sectors */
  off_t    fs_fsinfo;              /* MBR: Sector number of FSINFO sector */
  off_t    fs_currentsector;       /* The sector number buffered in fs_buffer */
  uint32_t fs_nclusters;           /* Maximum number of data clusters */
  uint32_t fs_nfatsects;           /* MBR: Count of sectors occupied by one fat */
  uint32_t fs_fattotsec;           /* MBR: Total count of sectors on the volume */
  uint32_t fs_fsifreecount;        /* FSI: Last free cluster count on volume */
  uint32_t fs_fsinextfree;         /* FSI: Cluster number of 1st free cluster */
  uint16_t fs_fatresvdseccount;    /* MBR: The total number of reserved sectors */
  uint16_t fs_rootentcnt;          /* MBR: Count of 32-bit root directory entries */
  bool     fs_mounted;             /* true: The file system is ready */
  bool     fs_dirty;               /* true: fs_buffer is dirty */
  bool     fs_fsidirty;            /* true: FSINFO sector must be written to disk */
  uint8_t  fs_type;                /* FSTYPE_FAT12, FSTYPE_FAT16, or FSTYPE_FAT32 */
  uint8_t  fs_fatnumfats;          /* MBR: Number of FATs (probably 2) */
  uint8_t  fs_fatsecperclus;       /* MBR: Sectors per allocation unit: 2**n, n=0..7 */
  uint8_t *fs_buffer;              /* This is an allocated buffer to hold one
                                    * sector from the device */
};

/* This structure represents on open file under the mountpoint.  An instance
 * of this structure is retained as struct file specific information on each
 * opened file.
 */

struct fat_file_s
{
  struct fat_file_s *ff_next;      /* Retained in a singly linked list */
  uint8_t  ff_bflags;              /* The file buffer/mount flags */
  uint8_t  ff_oflags;              /* Flags provided when file was opened */
  uint8_t  ff_sectorsincluster;    /* Sectors remaining in cluster */
  uint16_t ff_dirindex;            /* Index into ff_dirsector to directory entry */
  uint32_t ff_currentcluster;      /* Current cluster being accessed */
  off_t    ff_dirsector;           /* Sector containing the directory entry */
  off_t    ff_size;                /* Size of the file in bytes */
  off_t    ff_startcluster;        /* Start cluster of file on media */
  off_t    ff_currentsector;       /* Current sector being operated on */
  off_t    ff_cachesector;         /* Current sector in the file buffer */
  uint8_t *ff_buffer;              /* File buffer (for partial sector accesses) */
};

/* This structure holds the sequence of directory entries used by one
 * file element (directory or file).  For short file names, this is
 * single directory entry.  But for long file names, the is a sequence
 * of directory entries.  Long directory name entries appear in reverse
 * order: Last, next-to-last, ..., first.  The "first" long file name
 * directory is then following by the short directory name entry.  The
 * short file name entry contains the real meat of the file data.
 *
 * So it takes the sector number and entry offset of the last long
 * file name entry and of the short file name entry to define the
 * sequence.  In the case of short file names, the sector number and
 * offset will be the same.
 */

struct fat_dirseq_s
{
  /* Sector offsets */

  uint16_t ds_offset;              /* Sector offset to short file name entry */
#ifdef CONFIG_FAT_LFN
  uint16_t ds_lfnoffset;           /* Sector offset to last long file name entry */
#endif

  /* Sector and cluster numbers */

  off_t    ds_sector;              /* Sector of the short file name entry */
#ifdef CONFIG_FAT_LFN
  off_t    ds_cluster;             /* Cluster containing the short file name entry */
  off_t    ds_lfnsector;           /* Sector of the last long name entry */
  off_t    ds_lfncluster;          /* Cluster containing the long file name entry */
  off_t    ds_startsector;         /* Starting sector of the directory */
#endif
};

#ifdef CONFIG_FAT_LFN
#  ifdef CONFIG_FAT_LFN_UTF8
typedef uint16_t lfnchar;
#  else
typedef uint8_t lfnchar;
#  endif
#endif

struct fs_fatdir_s
{
  off_t        fd_startcluster;    /* Start cluster number of the directory */
  off_t        fd_currcluster;     /* Current cluster number being read */
  off_t        fd_currsector;      /* Current sector being read */
  unsigned int fd_index;           /* Current index of the directory entry to read */
};

struct fat_dirent_s
{
  struct fs_dirent_s base;
  struct fs_fatdir_s dir;
};

/* This structure is used internally for describing directory entries */

struct fat_dirinfo_s
{
  /* The file/directory name */

#ifdef CONFIG_FAT_LFN
  lfnchar fd_lfname[LDIR_MAXFNAME + 1]; /* Long filename with terminator */
#endif
  uint8_t fd_name[DIR_MAXFNAME];   /* Short 8.3 alias filename (no terminator) */

  /* NT flags are not used */

#ifdef CONFIG_FAT_LCNAMES
  uint8_t  fd_ntflags;             /* NTRes lower case flags */
#endif

  /* TRUE if this is the root directory */

  bool     fd_root;

  /* The following provides the sequence of directory entries used by the
   * file or directory.
   */

  struct fat_dirseq_s fd_seq;      /* Directory sequence */

  /* This is part of the opendir, readdir, ... logic */

  struct fs_fatdir_s dir;          /* Used with opendir, readdir, etc. */
};

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

#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/* Utitilies to handle unaligned or byte swapped accesses */

EXTERN uint16_t fat_getuint16(uint8_t *ptr);
EXTERN uint32_t fat_getuint32(uint8_t *ptr);
EXTERN void   fat_putuint16(uint8_t *ptr, uint16_t value16);
EXTERN void   fat_putuint32(uint8_t *ptr, uint32_t value32);

/* Manage the per-mount semaphore that protects access to shared resources */

EXTERN int    fat_semtake(struct fat_mountpt_s *fs);
EXTERN void   fat_semgive(struct fat_mountpt_s *fs);

/* Get the current time for FAT creation and write times */

EXTERN uint32_t fat_systime2fattime(void);
EXTERN time_t fat_fattime2systime(uint16_t fattime, uint16_t fatdate);

/* Handle hardware interactions for mounting */

EXTERN int    fat_mount(struct fat_mountpt_s *fs, bool writeable);
EXTERN int    fat_checkmount(struct fat_mountpt_s *fs);

/* low-level hardware access */

EXTERN int    fat_hwread(struct fat_mountpt_s *fs, uint8_t *buffer,
                         off_t sector, unsigned int nsectors);
EXTERN int    fat_hwwrite(struct fat_mountpt_s *fs, uint8_t *buffer,
                          off_t sector, unsigned int nsectors);

/* Cluster / cluster chain access helpers */

EXTERN off_t  fat_cluster2sector(struct fat_mountpt_s *fs, uint32_t cluster);
EXTERN off_t  fat_getcluster(struct fat_mountpt_s *fs, uint32_t clusterno);
EXTERN int    fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno,
                             off_t startsector);
EXTERN int    fat_removechain(struct fat_mountpt_s *fs, uint32_t cluster);
EXTERN int32_t fat_extendchain(struct fat_mountpt_s *fs, uint32_t cluster);

#define fat_createchain(fs) fat_extendchain(fs, 0)

/* Help for traversing directory trees and accessing directory entries */

EXTERN int    fat_nextdirentry(struct fat_mountpt_s *fs,
                               struct fs_fatdir_s *dir);
EXTERN int    fat_finddirentry(struct fat_mountpt_s *fs,
                               struct fat_dirinfo_s *dirinfo,
                               const char *path);
EXTERN int    fat_dirnamewrite(struct fat_mountpt_s *fs,
                               struct fat_dirinfo_s *dirinfo);
EXTERN int    fat_dirwrite(struct fat_mountpt_s *fs,
                           struct fat_dirinfo_s *dirinfo,
                           uint8_t attributes, uint32_t fattime);
EXTERN int    fat_allocatedirentry(struct fat_mountpt_s *fs,
                                   struct fat_dirinfo_s *dirinfo);
EXTERN int    fat_freedirentry(struct fat_mountpt_s *fs,
                               struct fat_dirseq_s *seq);
EXTERN int    fat_dirname2path(FAR struct fat_mountpt_s *fs,
                               FAR struct fs_dirent_s *dir,
                               FAR struct dirent *entry);

/* File creation and removal helpers */

EXTERN int    fat_dirtruncate(struct fat_mountpt_s *fs,
                              FAR uint8_t *direntry);
EXTERN int    fat_dirshrink(struct fat_mountpt_s *fs, FAR uint8_t *direntry,
                            off_t length);
EXTERN int    fat_dirextend(FAR struct fat_mountpt_s *fs,
                            FAR struct fat_file_s *ff, off_t length);
EXTERN int    fat_dircreate(struct fat_mountpt_s *fs,
                            struct fat_dirinfo_s *dirinfo);
EXTERN int    fat_remove(struct fat_mountpt_s *fs, const char *relpath,
                         bool directory);

/* Mountpoint and file buffer cache (for partial sector accesses) */

EXTERN int    fat_fscacheflush(struct fat_mountpt_s *fs);
EXTERN int    fat_fscacheread(struct fat_mountpt_s *fs, off_t sector);
EXTERN int    fat_ffcacheflush(struct fat_mountpt_s *fs,
                               struct fat_file_s *ff);
EXTERN int    fat_ffcacheread(struct fat_mountpt_s *fs,
                              struct fat_file_s *ff, off_t sector);
EXTERN int    fat_ffcacheinvalidate(struct fat_mountpt_s *fs,
                                    struct fat_file_s *ff);

/* FSINFO sector support */

EXTERN int    fat_updatefsinfo(struct fat_mountpt_s *fs);
EXTERN int    fat_computefreeclusters(struct fat_mountpt_s *fs);
EXTERN int    fat_nfreeclusters(struct fat_mountpt_s *fs,
                                fsblkcnt_t *pfreeclusters);
EXTERN int    fat_currentsector(struct fat_mountpt_s *fs,
                                struct fat_file_s *ff, off_t position);

#undef EXTERN
#if defined(__cplusplus)
}
#endif

#endif /* __FS_FAT_FS_FAT32_H */