include/fat.h

   1 /*
   2  * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
   3  *
   4  * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
   5  * 2003-03-10 - kharris@nexus-tech.net - ported to u-boot
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #ifndef _FAT_H_
  11 #define _FAT_H_
  12
  13 #include <asm/byteorder.h>
  14 #include <fs.h>
  15
  16 /* Maximum Long File Name length supported here is 128 UTF-16 code units */
  17 #define VFAT_MAXLEN_BYTES       256 /* Maximum LFN buffer in bytes */
  18 #define VFAT_MAXSEQ             9   /* Up to 9 of 13 2-byte UTF-16 entries */
  19 #define PREFETCH_BLOCKS         2
  20
  21 #define MAX_CLUSTSIZE   CONFIG_FS_FAT_MAX_CLUSTSIZE
  22
  23 #define DIRENTSPERBLOCK (mydata->sect_size / sizeof(dir_entry))
  24 #define DIRENTSPERCLUST ((mydata->clust_size * mydata->sect_size) / \
  25                          sizeof(dir_entry))
  26
  27 #define FATBUFBLOCKS    6
  28 #define FATBUFSIZE      (mydata->sect_size * FATBUFBLOCKS)
  29 #define FAT12BUFSIZE    ((FATBUFSIZE*2)/3)
  30 #define FAT16BUFSIZE    (FATBUFSIZE/2)
  31 #define FAT32BUFSIZE    (FATBUFSIZE/4)
  32
  33 /* Maximum number of entry for long file name according to spec */
  34 #define MAX_LFN_SLOT    20
  35
  36 /* Filesystem identifiers */
  37 #define FAT12_SIGN      "FAT12   "
  38 #define FAT16_SIGN      "FAT16   "
  39 #define FAT32_SIGN      "FAT32   "
  40 #define SIGNLEN         8
  41
  42 /* File attributes */
  43 #define ATTR_RO 1
  44 #define ATTR_HIDDEN     2
  45 #define ATTR_SYS        4
  46 #define ATTR_VOLUME     8
  47 #define ATTR_DIR        16
  48 #define ATTR_ARCH       32
  49
  50 #define ATTR_VFAT       (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
  51
  52 #define DELETED_FLAG    ((char)0xe5) /* Marks deleted files when in name[0] */
  53 #define aRING           0x05         /* Used as special character in name[0] */
  54
  55 /*
  56  * Indicates that the entry is the last long entry in a set of long
  57  * dir entries
  58  */
  59 #define LAST_LONG_ENTRY_MASK    0x40
  60
  61 #define ISDIRDELIM(c)   ((c) == '/' || (c) == '\\')
  62
  63 #define FSTYPE_NONE     (-1)
  64
  65 #if defined(__linux__) && defined(__KERNEL__)
  66 #define FAT2CPU16       le16_to_cpu
  67 #define FAT2CPU32       le32_to_cpu
  68 #else
  69 #if __LITTLE_ENDIAN
  70 #define FAT2CPU16(x)    (x)
  71 #define FAT2CPU32(x)    (x)
  72 #else
  73 #define FAT2CPU16(x)    ((((x) & 0x00ff) << 8) | (((x) & 0xff00) >> 8))
  74 #define FAT2CPU32(x)    ((((x) & 0x000000ff) << 24)  |  \
  75                          (((x) & 0x0000ff00) << 8)  |   \
  76                          (((x) & 0x00ff0000) >> 8)  |   \
  77                          (((x) & 0xff000000) >> 24))
  78 #endif
  79 #endif
  80
  81 #define START(dent)     (FAT2CPU16((dent)->start) \
  82                         + (mydata->fatsize != 32 ? 0 : \
  83                           (FAT2CPU16((dent)->starthi) << 16)))
  84 #define IS_LAST_CLUST(x, fatsize) ((x) >= ((fatsize) != 32 ? \
  85                                         ((fatsize) != 16 ? 0xff8 : 0xfff8) : \
  86                                         0xffffff8))
  87 #define CHECK_CLUST(x, fatsize) ((x) <= 1 || \
  88                                 (x) >= ((fatsize) != 32 ? \
  89                                         ((fatsize) != 16 ? 0xff0 : 0xfff0) : \
  90                                         0xffffff0))
  91
  92 typedef struct boot_sector {
  93         __u8    ignored[3];     /* Bootstrap code */
  94         char    system_id[8];   /* Name of fs */
  95         __u8    sector_size[2]; /* Bytes/sector */
  96         __u8    cluster_size;   /* Sectors/cluster */
  97         __u16   reserved;       /* Number of reserved sectors */
  98         __u8    fats;           /* Number of FATs */
  99         __u8    dir_entries[2]; /* Number of root directory entries */
 100         __u8    sectors[2];     /* Number of sectors */
 101         __u8    media;          /* Media code */
 102         __u16   fat_length;     /* Sectors/FAT */
 103         __u16   secs_track;     /* Sectors/track */
 104         __u16   heads;          /* Number of heads */
 105         __u32   hidden;         /* Number of hidden sectors */
 106         __u32   total_sect;     /* Number of sectors (if sectors == 0) */
 107
 108         /* FAT32 only */
 109         __u32   fat32_length;   /* Sectors/FAT */
 110         __u16   flags;          /* Bit 8: fat mirroring, low 4: active fat */
 111         __u8    version[2];     /* Filesystem version */
 112         __u32   root_cluster;   /* First cluster in root directory */
 113         __u16   info_sector;    /* Filesystem info sector */
 114         __u16   backup_boot;    /* Backup boot sector */
 115         __u16   reserved2[6];   /* Unused */
 116 } boot_sector;
 117
 118 typedef struct volume_info
 119 {
 120         __u8 drive_number;      /* BIOS drive number */
 121         __u8 reserved;          /* Unused */
 122         __u8 ext_boot_sign;     /* 0x29 if fields below exist (DOS 3.3+) */
 123         __u8 volume_id[4];      /* Volume ID number */
 124         char volume_label[11];  /* Volume label */
 125         char fs_type[8];        /* Typically FAT12, FAT16, or FAT32 */
 126         /* Boot code comes next, all but 2 bytes to fill up sector */
 127         /* Boot sign comes last, 2 bytes */
 128 } volume_info;
 129
 130 /* see dir_entry::lcase: */
 131 #define CASE_LOWER_BASE 8       /* base (name) is lower case */
 132 #define CASE_LOWER_EXT  16      /* extension is lower case */
 133
 134 typedef struct dir_entry {
 135         char    name[8],ext[3]; /* Name and extension */
 136         __u8    attr;           /* Attribute bits */
 137         __u8    lcase;          /* Case for name and ext (CASE_LOWER_x) */
 138         __u8    ctime_ms;       /* Creation time, milliseconds */
 139         __u16   ctime;          /* Creation time */
 140         __u16   cdate;          /* Creation date */
 141         __u16   adate;          /* Last access date */
 142         __u16   starthi;        /* High 16 bits of cluster in FAT32 */
 143         __u16   time,date,start;/* Time, date and first cluster */
 144         __u32   size;           /* File size in bytes */
 145 } dir_entry;
 146
 147 typedef struct dir_slot {
 148         __u8    id;             /* Sequence number for slot */
 149         __u8    name0_4[10];    /* First 5 characters in name */
 150         __u8    attr;           /* Attribute byte */
 151         __u8    reserved;       /* Unused */
 152         __u8    alias_checksum;/* Checksum for 8.3 alias */
 153         __u8    name5_10[12];   /* 6 more characters in name */
 154         __u16   start;          /* Unused */
 155         __u8    name11_12[4];   /* Last 2 characters in name */
 156 } dir_slot;
 157
 158 /*
 159  * Private filesystem parameters
 160  *
 161  * Note: FAT buffer has to be 32 bit aligned
 162  * (see FAT32 accesses)
 163  */
 164 typedef struct {
 165         __u8    *fatbuf;        /* Current FAT buffer */
 166         int     fatsize;        /* Size of FAT in bits */
 167         __u32   fatlength;      /* Length of FAT in sectors */
 168         __u16   fat_sect;       /* Starting sector of the FAT */
 169         __u8    fat_dirty;      /* Set if fatbuf has been modified */
 170         __u32   rootdir_sect;   /* Start sector of root directory */
 171         __u16   sect_size;      /* Size of sectors in bytes */
 172         __u16   clust_size;     /* Size of clusters in sectors */
 173         int     data_begin;     /* The sector of the first cluster, can be negative */
 174         int     fatbufnum;      /* Used by get_fatent, init to -1 */
 175         int     rootdir_size;   /* Size of root dir for non-FAT32 */
 176         __u32   root_cluster;   /* First cluster of root dir for FAT32 */
 177 } fsdata;
 178
 179 static inline u32 clust_to_sect(fsdata *fsdata, u32 clust)
 180 {
 181         return fsdata->data_begin + clust * fsdata->clust_size;
 182 }
 183
 184 static inline u32 sect_to_clust(fsdata *fsdata, u32 sect)
 185 {
 186         return (sect - fsdata->data_begin) / fsdata->clust_size;
 187 }
 188
 189 int file_fat_detectfs(void);
 190 int fat_exists(const char *filename);
 191 int fat_size(const char *filename, loff_t *size);
 192 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 193                      loff_t maxsize, loff_t *actread);
 194 int file_fat_read(const char *filename, void *buffer, int maxsize);
 195 int fat_set_blk_dev(struct blk_desc *rbdd, disk_partition_t *info);
 196 int fat_register_device(struct blk_desc *dev_desc, int part_no);
 197
 198 int file_fat_write(const char *filename, void *buf, loff_t offset, loff_t len,
 199                    loff_t *actwrite);
 200 int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
 201                   loff_t *actread);
 202 int fat_opendir(const char *filename, struct fs_dir_stream **dirsp);
 203 int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
 204 void fat_closedir(struct fs_dir_stream *dirs);
 205 void fat_close(void);
 206 #endif /* _FAT_H_ */