xref: /openbmc/u-boot/include/fat.h (revision 0f44d33536a50ef65259c322fa2d4a058585caf9)
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_ */
207