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