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发表于 2017-3-24 15:32:34
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我的现在也是这个问题(读U盘)
----------求指教
static
FRESULT chk_mounted ( /* FR_OK(0): successful, !=0: any error occurred */
const TCHAR **path, /* Pointer to pointer to the path name (drive number) */
FATFS **rfs, /* Pointer to pointer to the found file system object */
BYTE wmode /* !=0: Check write protection for write access */
)
{
BYTE fmt, b, pi, *tbl;
UINT vol;
DSTATUS stat;
DWORD bsect, fasize, tsect, sysect, nclst, szbfat;
WORD nrsv;
const TCHAR *p = *path;
FATFS *fs;
/* Get logical drive number from the path name */
vol = p[0] - '0'; /* Is there a drive number? */
if (vol <= 9 && p[1] == ':') { /* Found a drive number, get and strip it */
p += 2; *path = p; /* Return pointer to the path name */
} else { /* No drive number, use default drive */
#if _FS_RPATH
vol = CurrVol; /* Use current drive */
#else
vol = 0; /* Use drive 0 */
#endif
}
/* Check if the file system object is valid or not */
*rfs = 0;
if (vol >= _VOLUMES) /* Is the drive number valid? */
return FR_INVALID_DRIVE;
fs = FatFs[vol]; /* Get corresponding file system object */
if (!fs) return FR_NOT_ENABLED; /* Is the file system object available? */
ENTER_FF(fs); /* Lock volume */
*rfs = fs; /* Return pointer to the corresponding file system object */
if (fs->fs_type) { /* If the volume has been mounted */
stat = disk_status(fs->drv);
if (!(stat & STA_NOINIT)) { /* and the physical drive is kept initialized (has not been changed), */
if (!_FS_READONLY && wmode && (stat & STA_PROTECT)) /* Check write protection if needed */
return FR_WRITE_PROTECTED;
return FR_OK; /* The file system object is valid */
}
}
/* The file system object is not valid. */
/* Following code attempts to mount the volume. (analyze BPB and initialize the fs object) */
fs->fs_type = 0; /* Clear the file system object */
fs->drv = LD2PD(vol); /* Bind the logical drive and a physical drive */
stat = disk_initialize(fs->drv); /* Initialize the physical drive */
if (stat & STA_NOINIT) /* Check if the initialization succeeded */
return FR_NOT_READY; /* Failed to initialize due to no medium or hard error */ -------------------------------这里报错，不知道原因，求高手指教
if (!_FS_READONLY && wmode && (stat & STA_PROTECT)) /* Check disk write protection if needed */
return FR_WRITE_PROTECTED;
#if _MAX_SS != 512 /* Get disk sector size (variable sector size cfg only) */
if (disk_ioctl(fs->drv, GET_SECTOR_SIZE, &fs->ssize) != RES_OK)
return FR_DISK_ERR;
#endif
/* Search FAT partition on the drive. Supports only generic partitions, FDISK and SFD. */
fmt = check_fs(fs, bsect = 0); /* Load sector 0 and check if it is an FAT-VBR (in SFD) */
if (LD2PT(vol) && !fmt) fmt = 1; /* Force non-SFD if the volume is forced partition */
if (fmt == 1) { /* Not an FAT-VBR, the physical drive can be partitioned */
/* Check the partition listed in the partition table */
pi = LD2PT(vol);
if (pi) pi--;
tbl = &fs->win[MBR_Table + pi * SZ_PTE];/* Partition table */
if (tbl[4]) { /* Is the partition existing? */
bsect = LD_DWORD(&tbl[8]); /* Partition offset in LBA */
fmt = check_fs(fs, bsect); /* Check the partition */
}
}
if (fmt == 3) return FR_DISK_ERR;
if (fmt) return FR_NO_FILESYSTEM; /* No FAT volume is found */
/* An FAT volume is found. Following code initializes the file system object */
if (LD_WORD(fs->win+BPB_BytsPerSec) != SS(fs)) /* (BPB_BytsPerSec must be equal to the physical sector size) */
return FR_NO_FILESYSTEM;
fasize = LD_WORD(fs->win+BPB_FATSz16); /* Number of sectors per FAT */
if (!fasize) fasize = LD_DWORD(fs->win+BPB_FATSz32);
fs->fsize = fasize;
fs->n_fats = b = fs->win[BPB_NumFATs]; /* Number of FAT copies */
if (b != 1 && b != 2) return FR_NO_FILESYSTEM; /* (Must be 1 or 2) */
fasize *= b; /* Number of sectors for FAT area */
fs->csize = b = fs->win[BPB_SecPerClus]; /* Number of sectors per cluster */
if (!b || (b & (b - 1))) return FR_NO_FILESYSTEM; /* (Must be power of 2) */
fs->n_rootdir = LD_WORD(fs->win+BPB_RootEntCnt); /* Number of root directory entries */
if (fs->n_rootdir % (SS(fs) / SZ_DIR)) return FR_NO_FILESYSTEM; /* (BPB_RootEntCnt must be sector aligned) */
tsect = LD_WORD(fs->win+BPB_TotSec16); /* Number of sectors on the volume */
if (!tsect) tsect = LD_DWORD(fs->win+BPB_TotSec32);
nrsv = LD_WORD(fs->win+BPB_RsvdSecCnt); /* Number of reserved sectors */
if (!nrsv) return FR_NO_FILESYSTEM; /* (BPB_RsvdSecCnt must not be 0) */
/* Determine the FAT sub type */
sysect = nrsv + fasize + fs->n_rootdir / (SS(fs) / SZ_DIR); /* RSV+FAT+DIR */
if (tsect < sysect) return FR_NO_FILESYSTEM; /* (Invalid volume size) */
nclst = (tsect - sysect) / fs->csize; /* Number of clusters */
if (!nclst) return FR_NO_FILESYSTEM; /* (Invalid volume size) */
fmt = FS_FAT12;
if (nclst >= MIN_FAT16) fmt = FS_FAT16;
if (nclst >= MIN_FAT32) fmt = FS_FAT32;
/* Boundaries and Limits */
fs->n_fatent = nclst + 2; /* Number of FAT entries */
fs->volbase = bsect; /* Volume start sector */
fs->fatbase = bsect + nrsv; /* FAT start sector */
fs->database = bsect + sysect; /* Data start sector */
if (fmt == FS_FAT32) {
if (fs->n_rootdir) return FR_NO_FILESYSTEM; /* (BPB_RootEntCnt must be 0) */
fs->dirbase = LD_DWORD(fs->win+BPB_RootClus); /* Root directory start cluster */
szbfat = fs->n_fatent * 4; /* (Required FAT size) */
} else {
if (!fs->n_rootdir) return FR_NO_FILESYSTEM; /* (BPB_RootEntCnt must not be 0) */
fs->dirbase = fs->fatbase + fasize; /* Root directory start sector */
szbfat = (fmt == FS_FAT16) ? /* (Required FAT size) */
fs->n_fatent * 2 : fs->n_fatent * 3 / 2 + (fs->n_fatent & 1);
}
if (fs->fsize < (szbfat + (SS(fs) - 1)) / SS(fs)) /* (BPB_FATSz must not be less than required) */
return FR_NO_FILESYSTEM;
#if !_FS_READONLY
/* Initialize cluster allocation information */
fs->free_clust = 0xFFFFFFFF;
fs->last_clust = 0;
/* Get fsinfo if available */
if (fmt == FS_FAT32) {
fs->fsi_flag = 0;
fs->fsi_sector = bsect + LD_WORD(fs->win+BPB_FSInfo);
if (disk_read(fs->drv, fs->win, fs->fsi_sector, 1) == RES_OK &&
LD_WORD(fs->win+BS_55AA) == 0xAA55 &&
LD_DWORD(fs->win+FSI_LeadSig) == 0x41615252 &&
LD_DWORD(fs->win+FSI_StrucSig) == 0x61417272) {
fs->last_clust = LD_DWORD(fs->win+FSI_Nxt_Free);
fs->free_clust = LD_DWORD(fs->win+FSI_Free_Count);
}
}
#endif
fs->fs_type = fmt; /* FAT sub-type */
fs->id = ++Fsid; /* File system mount ID */
fs->winsect = 0; /* Invalidate sector cache */
fs->wflag = 0;
#if _FS_RPATH
fs->cdir = 0; /* Current directory (root dir) */
#endif
#if _FS_LOCK /* Clear file lock semaphores */
clear_lock(fs);
#endif
return FR_OK;
} |
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