1 /*-----------------------------------------------------------------------*/
2 /* Create File System on the Drive */
3 /*-----------------------------------------------------------------------*/
4
5 FRESULT f_mkfs (
6 BYTE drv, /* Logical drive number */
7 BYTE sfd, /* Partitioning rule 0:FDISK, 1:SFD */
8 UINT au /* Allocation unit size [bytes] */
9 )
10 {
11 static const WORD vst[] = { 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 0};
12 static const WORD cst[] = {32768, 16384, 8192, 4096, 2048, 16384, 8192, 4096, 2048, 1024, 512};
13 BYTE fmt, md, sys, *tbl, pdrv, part;
14 DWORD n_clst, vs, n, wsect;
15 UINT i;
16 DWORD b_vol, b_fat, b_dir, b_data; /* LBA */
17 DWORD n_vol, n_rsv, n_fat, n_dir; /* Size */
18 FATFS *fs;
19 DSTATUS stat;
20
21
22 /* Check mounted drive and clear work area */
23 if (drv >= _VOLUMES) return FR_INVALID_DRIVE;
24 if (sfd > 1) return FR_INVALID_PARAMETER;
25 if (au & (au - 1)) return FR_INVALID_PARAMETER;
26 fs = FatFs[drv];
27 if (!fs) return FR_NOT_ENABLED;
28 fs->fs_type = 0;
29 pdrv = LD2PD(drv); /* Physical drive */
30 part = LD2PT(drv); /* Partition (0:auto detect, 1-4:get from partition table)*/
31
32 /* Get disk statics */
33 stat = disk_initialize(pdrv);
34 if (stat & STA_NOINIT) return FR_NOT_READY;
35 if (stat & STA_PROTECT) return FR_WRITE_PROTECTED;
36 #if _MAX_SS != 512 /* Get disk sector size */
37 if (disk_ioctl(pdrv, GET_SECTOR_SIZE, &SS(fs)) != RES_OK || SS(fs) > _MAX_SS)
38 return FR_DISK_ERR;
39 #endif
40 if (_MULTI_PARTITION && part) {
41 /* Get partition information from partition table in the MBR */
42 if (disk_read(pdrv, fs->win, 0, 1) != RES_OK) return FR_DISK_ERR;
43 if (LD_WORD(fs->win+BS_55AA) != 0xAA55) return FR_MKFS_ABORTED;
44 tbl = &fs->win[MBR_Table + (part - 1) * SZ_PTE];
45 if (!tbl[4]) return FR_MKFS_ABORTED; /* No partition? */
46 b_vol = LD_DWORD(tbl+8); /* Volume start sector */
47 n_vol = LD_DWORD(tbl+12); /* Volume size */
48 } else {
49 /* Create a partition in this function */
50 if (disk_ioctl(pdrv, GET_SECTOR_COUNT, &n_vol) != RES_OK || n_vol < 128)
51 return FR_DISK_ERR;
52 b_vol = (sfd) ? 0 : 63; /* Volume start sector */
53 n_vol -= b_vol; /* Volume size */
54 }
55
56 if (!au) { /* AU auto selection */
57 vs = n_vol / (2000 / (SS(fs) / 512));
58 for (i = 0; vs < vst[i]; i++) ;
59 au = cst[i];
60 }
61 au /= SS(fs); /* Number of sectors per cluster */
62 if (au == 0) au = 1;
63 if (au > 128) au = 128;
64
65 /* Pre-compute number of clusters and FAT syb-type */
66 n_clst = n_vol / au;
67 fmt = FS_FAT12;
68 if (n_clst >= MIN_FAT16) fmt = FS_FAT16;
69 if (n_clst >= MIN_FAT32) fmt = FS_FAT32;
70
71 /* Determine offset and size of FAT structure */
72 if (fmt == FS_FAT32) {
73 n_fat = ((n_clst * 4) + 8 + SS(fs) - 1) / SS(fs);
74 n_rsv = 32;
75 n_dir = 0;
76 } else {
77 n_fat = (fmt == FS_FAT12) ? (n_clst * 3 + 1) / 2 + 3 : (n_clst * 2) + 4;
78 n_fat = (n_fat + SS(fs) - 1) / SS(fs);
79 n_rsv = 1;
80 n_dir = (DWORD)N_ROOTDIR * SZ_DIR / SS(fs);
81 }
82 b_fat = b_vol + n_rsv; /* FAT area start sector */
83 b_dir = b_fat + n_fat * N_FATS; /* Directory area start sector */
84 b_data = b_dir + n_dir; /* Data area start sector */
85 if (n_vol < b_data + au - b_vol) return FR_MKFS_ABORTED; /* Too small volume */
86
87 /* Align data start sector to erase block boundary (for flash memory media) */
88 if (disk_ioctl(pdrv, GET_BLOCK_SIZE, &n) != RES_OK || !n || n > 32768) n = 1;
89 n = (b_data + n - 1) & ~(n - 1); /* Next nearest erase block from current data start */
90 n = (n - b_data) / N_FATS;
91 if (fmt == FS_FAT32) { /* FAT32: Move FAT offset */
92 n_rsv += n;
93 b_fat += n;
94 } else { /* FAT12/16: Expand FAT size */
95 n_fat += n;
96 }
97
98 /* Determine number of clusters and final check of validity of the FAT sub-type */
99 n_clst = (n_vol - n_rsv - n_fat * N_FATS - n_dir) / au;
100 if ( (fmt == FS_FAT16 && n_clst < MIN_FAT16)
101 || (fmt == FS_FAT32 && n_clst < MIN_FAT32))
102 return FR_MKFS_ABORTED;
103
104 switch (fmt) { /* Determine system ID for partition table */
105 case FS_FAT12: sys = 0x01; break;
106 case FS_FAT16: sys = (n_vol < 0x10000) ? 0x04 : 0x06; break;
107 default: sys = 0x0C;
108 }
109
110 if (_MULTI_PARTITION && part) {
111 /* Update system ID in the partition table */
112 tbl = &fs->win[MBR_Table + (part - 1) * SZ_PTE];
113 tbl[4] = sys;
114 if (disk_write(pdrv, fs->win, 0, 1) != RES_OK) return FR_DISK_ERR;
115 md = 0xF8;
116 } else {
117 if (sfd) { /* No patition table (SFD) */
118 md = 0xF0;
119 } else { /* Create partition table (FDISK) */
120 mem_set(fs->win, 0, SS(fs));
121 tbl = fs->win+MBR_Table; /* Create partiton table for single partition in the drive */
122 tbl[1] = 1; /* Partition start head */
123 tbl[2] = 1; /* Partition start sector */
124 tbl[3] = 0; /* Partition start cylinder */
125 tbl[4] = sys; /* System type */
126 tbl[5] = 254; /* Partition end head */
127 n = (b_vol + n_vol) / 63 / 255;
128 tbl[6] = (BYTE)((n >> 2) | 63); /* Partiiton end sector */
129 tbl[7] = (BYTE)n; /* End cylinder */
130 ST_DWORD(tbl+8, 63); /* Partition start in LBA */
131 ST_DWORD(tbl+12, n_vol); /* Partition size in LBA */
132 ST_WORD(fs->win+BS_55AA, 0xAA55); /* MBR signature */
133 if (disk_write(pdrv, fs->win, 0, 1) != RES_OK) /* Write it to the MBR sector */
134 return FR_DISK_ERR;
135 md = 0xF8;
136 }
137 }
138
139 /* Create BPB in the VBR */
140 tbl = fs->win; /* Clear sector */
141 mem_set(tbl, 0, SS(fs));
142 mem_cpy(tbl, "\xEB\xFE\x90" "MSDOS5.0", 11);/* Boot jump code, OEM name */
143 i = SS(fs); /* Sector size */
144 ST_WORD(tbl+BPB_BytsPerSec, i);
145 tbl[BPB_SecPerClus] = (BYTE)au; /* Sectors per cluster */
146 ST_WORD(tbl+BPB_RsvdSecCnt, n_rsv); /* Reserved sectors */
147 tbl[BPB_NumFATs] = N_FATS; /* Number of FATs */
148 i = (fmt == FS_FAT32) ? 0 : N_ROOTDIR; /* Number of rootdir entries */
149 ST_WORD(tbl+BPB_RootEntCnt, i);
150 if (n_vol < 0x10000) { /* Number of total sectors */
151 ST_WORD(tbl+BPB_TotSec16, n_vol);
152 } else {
153 ST_DWORD(tbl+BPB_TotSec32, n_vol);
154 }
155 tbl[BPB_Media] = md; /* Media descriptor */
156 ST_WORD(tbl+BPB_SecPerTrk, 63); /* Number of sectors per track */
157 ST_WORD(tbl+BPB_NumHeads, 255); /* Number of heads */
158 ST_DWORD(tbl+BPB_HiddSec, b_vol); /* Hidden sectors */
159 n = get_fattime(); /* Use current time as VSN */
160 if (fmt == FS_FAT32) {
161 ST_DWORD(tbl+BS_VolID32, n); /* VSN */
162 ST_DWORD(tbl+BPB_FATSz32, n_fat); /* Number of sectors per FAT */
163 ST_DWORD(tbl+BPB_RootClus, 2); /* Root directory start cluster (2) */
164 ST_WORD(tbl+BPB_FSInfo, 1); /* FSInfo record offset (VBR+1) */
165 ST_WORD(tbl+BPB_BkBootSec, 6); /* Backup boot record offset (VBR+6) */
166 tbl[BS_DrvNum32] = 0x80; /* Drive number */
167 tbl[BS_BootSig32] = 0x29; /* Extended boot signature */
168 mem_cpy(tbl+BS_VolLab32, "NO NAME " "FAT32 ", 19); /* Volume label, FAT signature */
169 } else {
170 ST_DWORD(tbl+BS_VolID, n); /* VSN */
171 ST_WORD(tbl+BPB_FATSz16, n_fat); /* Number of sectors per FAT */
172 tbl[BS_DrvNum] = 0x80; /* Drive number */
173 tbl[BS_BootSig] = 0x29; /* Extended boot signature */
174 mem_cpy(tbl+BS_VolLab, "NO NAME " "FAT ", 19); /* Volume label, FAT signature */
175 }
176 ST_WORD(tbl+BS_55AA, 0xAA55); /* Signature (Offset is fixed here regardless of sector size) */
177 if (disk_write(pdrv, tbl, b_vol, 1) != RES_OK) /* Write it to the VBR sector */
178 return FR_DISK_ERR;
179 if (fmt == FS_FAT32) /* Write backup VBR if needed (VBR+6) */
180 disk_write(pdrv, tbl, b_vol + 6, 1);
181
182 /* Initialize FAT area */
183 wsect = b_fat;
184 for (i = 0; i < N_FATS; i++) { /* Initialize each FAT copy */
185 mem_set(tbl, 0, SS(fs)); /* 1st sector of the FAT */
186 n = md; /* Media descriptor byte */
187 if (fmt != FS_FAT32) {
188 n |= (fmt == FS_FAT12) ? 0x00FFFF00 : 0xFFFFFF00;
189 ST_DWORD(tbl+0, n); /* Reserve cluster #0-1 (FAT12/16) */
190 } else {
191 n |= 0xFFFFFF00;
192 ST_DWORD(tbl+0, n); /* Reserve cluster #0-1 (FAT32) */
193 ST_DWORD(tbl+4, 0xFFFFFFFF);
194 ST_DWORD(tbl+8, 0x0FFFFFFF); /* Reserve cluster #2 for root dir */
195 }
196 if (disk_write(pdrv, tbl, wsect++, 1) != RES_OK)
197 return FR_DISK_ERR;
198 mem_set(tbl, 0, SS(fs)); /* Fill following FAT entries with zero */
199 for (n = 1; n < n_fat; n++) { /* This loop may take a time on FAT32 volume due to many single sector writes */
200 if (disk_write(pdrv, tbl, wsect++, 1) != RES_OK)
201 return FR_DISK_ERR;
202 }
203 }
204
205 /* Initialize root directory */
206 i = (fmt == FS_FAT32) ? au : n_dir;
207 do {
208 if (disk_write(pdrv, tbl, wsect++, 1) != RES_OK)
209 return FR_DISK_ERR;
210 } while (--i);
211
212 #if _USE_ERASE /* Erase data area if needed */
213 {
214 DWORD eb[2];
215
216 eb[0] = wsect; eb[1] = wsect + (n_clst - ((fmt == FS_FAT32) ? 1 : 0)) * au - 1;
217 disk_ioctl(pdrv, CTRL_ERASE_SECTOR, eb);
218 }
219 #endif
220
221 /* Create FSInfo if needed */
222 if (fmt == FS_FAT32) {
223 ST_DWORD(tbl+FSI_LeadSig, 0x41615252);
224 ST_DWORD(tbl+FSI_StrucSig, 0x61417272);
225 ST_DWORD(tbl+FSI_Free_Count, n_clst - 1); /* Number of free clusters */
226 ST_DWORD(tbl+FSI_Nxt_Free, 2); /* Last allocated cluster# */
227 ST_WORD(tbl+BS_55AA, 0xAA55);
228 disk_write(pdrv, tbl, b_vol + 1, 1); /* Write original (VBR+1) */
229 disk_write(pdrv, tbl, b_vol + 7, 1); /* Write backup (VBR+7) */
230 }
231
232 return (disk_ioctl(pdrv, CTRL_SYNC, 0) == RES_OK) ? FR_OK : FR_DISK_ERR;
233 }
函数功能：在驱动器上创建一个文件系统(格式化 SD卡)
描述：
f_mkfs函数当_FS_READOLNY == 0并且_USE_MKFS == 1时可用。
f_mkfs函数在驱动器中创建一个FAT文件系统。对于可移动媒介，有两种分区规则：FDISK和SFD，通过参数PartitioningRule选择。FDISK格式在大多数情况下被推荐使用。该函数当前不支持多分区，因此，物理驱动器上已存在的分区将被删除，并且重新创建一个占据全部磁盘空间的新分区。
根据Microsoft发布的FAT规范，FAT分类：FAT12/FAT16/FAT32，由驱动器上的簇数决定。因此，选择哪种FAT分类，取决于卷大小和指定的簇大小。簇大小影响文件系统的性能，并且大簇会提高性能。
例：
1 FATFS fs;
2 FIL file;
3 FRESULT res;
4 char array[512]={0}, *parray = array;
5
6 res = f_mount(0, &fs);
7 res = f_mkfs(0 , 0, _MAX_SS);
8 res = f_open(&file, "data.txt", FA_OPEN_ALWAYS | FA_WRITE | FA_READ);
9 f_printf(&file, "%s\n", "Success"); /* "Success" */
10 parray = f_gets(parray , 8, &file);
11 LCMTextOutExt( 0, 0, parray );
12 f_close(&file);
13 f_mount(0, NULL);
FATFS 初学之 f_mkfs
时间： 2024-10-02 05:32:33