ff.c

LPC1788的USBHOST的FATFS移植

	return (acc || Files[i].ctr == 0x100) ? FR_LOCKED : FR_OK;
}


static
int enq_lock (	/* Check if an entry is available for a new file */
	FATFS* fs	/* File system object */
)
{
	UINT i;

	for (i = 0; i < _FS_SHARE && Files[i].fs; i++) ;
	return (i == _FS_SHARE) ? 0 : 1;
}


static
UINT inc_lock (	/* Increment file open counter and returns its index (0:int error) */
	DIR* dj,	/* Directory object pointing the file to register or increment */
	int acc		/* Desired access mode (0:Read, !0:Write) */
)
{
	UINT i;


	for (i = 0; i < _FS_SHARE; i++) {	/* Find the file */
		if (Files[i].fs == dj->fs &&
			Files[i].clu == dj->sclust &&
			Files[i].idx == dj->index) break;
	}

	if (i == _FS_SHARE) {				/* Not opened. Register it as new. */
		for (i = 0; i < _FS_SHARE && Files[i].fs; i++) ;
		if (i == _FS_SHARE) return 0;	/* No space to register (int err) */
		Files[i].fs = dj->fs;
		Files[i].clu = dj->sclust;
		Files[i].idx = dj->index;
		Files[i].ctr = 0;
	}

	if (acc && Files[i].ctr) return 0;	/* Access violation (int err) */

	Files[i].ctr = acc ? 0x100 : Files[i].ctr + 1;	/* Set semaphore value */

	return i + 1;
}


static
FRESULT dec_lock (	/* Decrement file open counter */
	UINT i			/* Semaphore index */
)
{
	WORD n;
	FRESULT res;


	if (--i < _FS_SHARE) {
		n = Files[i].ctr;
		if (n == 0x100) n = 0;
		if (n) n--;
		Files[i].ctr = n;
		if (!n) Files[i].fs = 0;
		res = FR_OK;
	} else {
		res = FR_INT_ERR;
	}
	return res;
}


static
void clear_lock (	/* Clear lock entries of the volume */
	FATFS *fs
)
{
	UINT i;

	for (i = 0; i < _FS_SHARE; i++) {
		if (Files[i].fs == fs) Files[i].fs = 0;
	}
}
#endif



/*-----------------------------------------------------------------------*/
/* Change window offset                                                  */
/*-----------------------------------------------------------------------*/

static
FRESULT move_window (
	FATFS *fs,		/* File system object */
	DWORD sector	/* Sector number to make appearance in the fs->win[] */
)					/* Move to zero only writes back dirty window */
{
	DWORD wsect;


	wsect = fs->winsect;
	if (wsect != sector) {	/* Changed current window */
#if !_FS_READONLY
		if (fs->wflag) {	/* Write back dirty window if needed */
			if (disk_write(fs->drv, fs->win, wsect, 1) != RES_OK)
				return FR_DISK_ERR;
			fs->wflag = 0;
			if (wsect < (fs->fatbase + fs->fsize)) {	/* In FAT area */
				BYTE nf;
				for (nf = fs->n_fats; nf > 1; nf--) {	/* Reflect the change to all FAT copies */
					wsect += fs->fsize;
					disk_write(fs->drv, fs->win, wsect, 1);
				}
			}
		}
#endif
		if (sector) {
			if (disk_read(fs->drv, fs->win, sector, 1) != RES_OK)
				return FR_DISK_ERR;
			fs->winsect = sector;
		}
	}

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Clean-up cached data                                                  */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY
static
FRESULT sync (	/* FR_OK: successful, FR_DISK_ERR: failed */
	FATFS *fs	/* File system object */
)
{
	FRESULT res;


	res = move_window(fs, 0);
	if (res == FR_OK) {
		/* Update FSInfo sector if needed */
		if (fs->fs_type == FS_FAT32 && fs->fsi_flag) {
			fs->winsect = 0;
			mem_set(fs->win, 0, 512);
			ST_WORD(fs->win+BS_55AA, 0xAA55);
			ST_DWORD(fs->win+FSI_LeadSig, 0x41615252);
			ST_DWORD(fs->win+FSI_StrucSig, 0x61417272);
			ST_DWORD(fs->win+FSI_Free_Count, fs->free_clust);
			ST_DWORD(fs->win+FSI_Nxt_Free, fs->last_clust);
			disk_write(fs->drv, fs->win, fs->fsi_sector, 1);
			fs->fsi_flag = 0;
		}
		/* Make sure that no pending write process in the physical drive */
		if (disk_ioctl(fs->drv, CTRL_SYNC, (void*)0) != RES_OK)
			res = FR_DISK_ERR;
	}

	return res;
}
#endif




/*-----------------------------------------------------------------------*/
/* Get sector# from cluster#                                             */
/*-----------------------------------------------------------------------*/


DWORD clust2sect (	/* !=0: Sector number, 0: Failed - invalid cluster# */
	FATFS *fs,		/* File system object */
	DWORD clst		/* Cluster# to be converted */
)
{
	clst -= 2;
	if (clst >= (fs->n_fatent - 2)) return 0;		/* Invalid cluster# */
	return clst * fs->csize + fs->database;
}




/*-----------------------------------------------------------------------*/
/* FAT access - Read value of a FAT entry                                */
/*-----------------------------------------------------------------------*/


DWORD get_fat (	/* 0xFFFFFFFF:Disk error, 1:Internal error, Else:Cluster status */
	FATFS *fs,	/* File system object */
	DWORD clst	/* Cluster# to get the link information */
)
{
	UINT wc, bc;
	BYTE *p;


	if (clst < 2 || clst >= fs->n_fatent)	/* Chack range */
		return 1;

	switch (fs->fs_type) {
	case FS_FAT12 :
		bc = (UINT)clst; bc += bc / 2;
		if (move_window(fs, fs->fatbase + (bc / SS(fs)))) break;
		wc = fs->win[bc % SS(fs)]; bc++;
		if (move_window(fs, fs->fatbase + (bc / SS(fs)))) break;
		wc |= fs->win[bc % SS(fs)] << 8;
		return (clst & 1) ? (wc >> 4) : (wc & 0xFFF);

	case FS_FAT16 :
		if (move_window(fs, fs->fatbase + (clst / (SS(fs) / 2)))) break;
		p = &fs->win[clst * 2 % SS(fs)];
		return LD_WORD(p);

	case FS_FAT32 :
		if (move_window(fs, fs->fatbase + (clst / (SS(fs) / 4)))) break;
		p = &fs->win[clst * 4 % SS(fs)];
		return LD_DWORD(p) & 0x0FFFFFFF;
	}

	return 0xFFFFFFFF;	/* An error occurred at the disk I/O layer */
}




/*-----------------------------------------------------------------------*/
/* FAT access - Change value of a FAT entry                              */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY

FRESULT put_fat (
	FATFS *fs,	/* File system object */
	DWORD clst,	/* Cluster# to be changed in range of 2 to fs->n_fatent - 1 */
	DWORD val	/* New value to mark the cluster */
)
{
	UINT bc;
	BYTE *p;
	FRESULT res;


	if (clst < 2 || clst >= fs->n_fatent) {	/* Check range */
		res = FR_INT_ERR;

	} else {
		switch (fs->fs_type) {
		case FS_FAT12 :
			bc = clst; bc += bc / 2;
			res = move_window(fs, fs->fatbase + (bc / SS(fs)));
			if (res != FR_OK) break;
			p = &fs->win[bc % SS(fs)];
			*p = (clst & 1) ? ((*p & 0x0F) | ((BYTE)val << 4)) : (BYTE)val;
			bc++;
			fs->wflag = 1;
			res = move_window(fs, fs->fatbase + (bc / SS(fs)));
			if (res != FR_OK) break;
			p = &fs->win[bc % SS(fs)];
			*p = (clst & 1) ? (BYTE)(val >> 4) : ((*p & 0xF0) | ((BYTE)(val >> 8) & 0x0F));
			break;

		case FS_FAT16 :
			res = move_window(fs, fs->fatbase + (clst / (SS(fs) / 2)));
			if (res != FR_OK) break;
			p = &fs->win[clst * 2 % SS(fs)];
			ST_WORD(p, (WORD)val);
			break;

		case FS_FAT32 :
			res = move_window(fs, fs->fatbase + (clst / (SS(fs) / 4)));
			if (res != FR_OK) break;
			p = &fs->win[clst * 4 % SS(fs)];
			val |= LD_DWORD(p) & 0xF0000000;
			ST_DWORD(p, val);
			break;

		default :
			res = FR_INT_ERR;
		}
		fs->wflag = 1;
	}

	return res;
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* FAT handling - Remove a cluster chain                                 */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY
static
FRESULT remove_chain (
	FATFS *fs,			/* File system object */
	DWORD clst			/* Cluster# to remove a chain from */
)
{
	FRESULT res;
	DWORD nxt;
#if _USE_ERASE
	DWORD scl = clst, ecl = clst, resion[2];
#endif

	if (clst < 2 || clst >= fs->n_fatent) {	/* Check range */
		res = FR_INT_ERR;

	} else {
		res = FR_OK;
		while (clst < fs->n_fatent) {			/* Not a last link? */
			nxt = get_fat(fs, clst);			/* Get cluster status */
			if (nxt == 0) break;				/* Empty cluster? */
			if (nxt == 1) { res = FR_INT_ERR; break; }	/* Internal error? */
			if (nxt == 0xFFFFFFFF) { res = FR_DISK_ERR; break; }	/* Disk error? */
			res = put_fat(fs, clst, 0);			/* Mark the cluster "empty" */
			if (res != FR_OK) break;
			if (fs->free_clust != 0xFFFFFFFF) {	/* Update FSInfo */
				fs->free_clust++;
				fs->fsi_flag = 1;
			}
#if _USE_ERASE
			if (ecl + 1 == nxt) {	/* Next cluster is contiguous */
				ecl = nxt;
			} else {				/* End of contiguous clusters */ 
				resion[0] = clust2sect(fs, scl);					/* Start sector */
				resion[1] = clust2sect(fs, ecl) + fs->csize - 1;	/* End sector */
				disk_ioctl(fs->drv, CTRL_ERASE_SECTOR, resion);		/* Erase the block */
				scl = ecl = nxt;
			}
#endif
			clst = nxt;	/* Next cluster */
		}
	}

	return res;
}
#endif




/*-----------------------------------------------------------------------*/
/* FAT handling - Stretch or Create a cluster chain                      */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY
static
DWORD create_chain (	/* 0:No free cluster, 1:Internal error, 0xFFFFFFFF:Disk error, >=2:New cluster# */
	FATFS *fs,			/* File system object */
	DWORD clst			/* Cluster# to stretch. 0 means create a new chain. */
)
{
	DWORD cs, ncl, scl;
	FRESULT res;


	if (clst == 0) {		/* Create a new chain */
		scl = fs->last_clust;			/* Get suggested start point */
		if (!scl || scl >= fs->n_fatent) scl = 1;
	}
	else {					/* Stretch the current chain */
		cs = get_fat(fs, clst);			/* Check the cluster status */
		if (cs < 2) return 1;			/* It is an invalid cluster */
		if (cs < fs->n_fatent) return cs;	/* It is already followed by next cluster */
		scl = clst;
	}

	ncl = scl;				/* Start cluster */
	for (;;) {
		ncl++;							/* Next cluster */
		if (ncl >= fs->n_fatent) {		/* Wrap around */
			ncl = 2;
			if (ncl > scl) return 0;	/* No free cluster */
		}
		cs = get_fat(fs, ncl);			/* Get the cluster status */
		if (cs == 0) break;				/* Found a free cluster */
		if (cs == 0xFFFFFFFF || cs == 1)/* An error occurred */
			return cs;
		if (ncl == scl) return 0;		/* No free cluster */
	}

	res = put_fat(fs, ncl, 0x0FFFFFFF);	/* Mark the new cluster "last link" */
	if (res == FR_OK && clst != 0) {
		res = put_fat(fs, clst, ncl);	/* Link it to the previous one if needed */
	}
	if (res == FR_OK) {
		fs->last_clust = ncl;			/* Update FSINFO */
		if (fs->free_clust != 0xFFFFFFFF) {
			fs->free_clust--;
			fs->fsi_flag = 1;
		}
	} else {
		ncl = (res == FR_DISK_ERR) ? 0xFFFFFFFF : 1;
	}

	return ncl;		/* Return new cluster number or error code */
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Directory handling - Set directory index                              */
/*-----------------------------------------------------------------------*/

static
FRESULT dir_sdi (
	DIR *dj,		/* Pointer to directory object */
	WORD idx		/* Directory index number */
)
{
	DWORD clst;
	WORD ic;