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