xref: /openbmc/u-boot/fs/fat/fat.c (revision 4e3349b6)
1 /*
2  * fat.c
3  *
4  * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
5  *
6  * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
7  * 2003-03-10 - kharris@nexus-tech.net - ported to uboot
8  *
9  * See file CREDITS for list of people who contributed to this
10  * project.
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of
15  * the License, or (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25  * MA 02111-1307 USA
26  */
27 
28 #include <common.h>
29 #include <config.h>
30 #include <exports.h>
31 #include <fat.h>
32 #include <asm/byteorder.h>
33 #include <part.h>
34 #include <malloc.h>
35 #include <linux/compiler.h>
36 
37 /*
38  * Convert a string to lowercase.
39  */
40 static void downcase (char *str)
41 {
42 	while (*str != '\0') {
43 		TOLOWER(*str);
44 		str++;
45 	}
46 }
47 
48 static block_dev_desc_t *cur_dev;
49 static unsigned int cur_part_nr;
50 static disk_partition_t cur_part_info;
51 
52 #define DOS_BOOT_MAGIC_OFFSET	0x1fe
53 #define DOS_FS_TYPE_OFFSET	0x36
54 #define DOS_FS32_TYPE_OFFSET	0x52
55 
56 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
57 {
58 	if (!cur_dev || !cur_dev->block_read)
59 		return -1;
60 
61 	return cur_dev->block_read(cur_dev->dev,
62 			cur_part_info.start + block, nr_blocks, buf);
63 }
64 
65 int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
66 {
67 	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
68 
69 	/* First close any currently found FAT filesystem */
70 	cur_dev = NULL;
71 
72 #if (defined(CONFIG_CMD_IDE) || \
73      defined(CONFIG_CMD_SATA) || \
74      defined(CONFIG_CMD_SCSI) || \
75      defined(CONFIG_CMD_USB) || \
76      defined(CONFIG_MMC) || \
77      defined(CONFIG_SYSTEMACE) )
78 
79 	/* Read the partition table, if present */
80 	if (!get_partition_info(dev_desc, part_no, &cur_part_info)) {
81 		cur_dev = dev_desc;
82 		cur_part_nr = part_no;
83 	}
84 #endif
85 
86 	/* Otherwise it might be a superfloppy (whole-disk FAT filesystem) */
87 	if (!cur_dev) {
88 		if (part_no != 1) {
89 			printf("** Partition %d not valid on device %d **\n",
90 					part_no, dev_desc->dev);
91 			return -1;
92 		}
93 
94 		cur_dev = dev_desc;
95 		cur_part_nr = 1;
96 		cur_part_info.start = 0;
97 		cur_part_info.size = dev_desc->lba;
98 		cur_part_info.blksz = dev_desc->blksz;
99 		memset(cur_part_info.name, 0, sizeof(cur_part_info.name));
100 		memset(cur_part_info.type, 0, sizeof(cur_part_info.type));
101 	}
102 
103 	/* Make sure it has a valid FAT header */
104 	if (disk_read(0, 1, buffer) != 1) {
105 		cur_dev = NULL;
106 		return -1;
107 	}
108 
109 	/* Check if it's actually a DOS volume */
110 	if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
111 		cur_dev = NULL;
112 		return -1;
113 	}
114 
115 	/* Check for FAT12/FAT16/FAT32 filesystem */
116 	if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
117 		return 0;
118 	if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
119 		return 0;
120 
121 	cur_dev = NULL;
122 	return -1;
123 }
124 
125 
126 /*
127  * Get the first occurence of a directory delimiter ('/' or '\') in a string.
128  * Return index into string if found, -1 otherwise.
129  */
130 static int dirdelim (char *str)
131 {
132 	char *start = str;
133 
134 	while (*str != '\0') {
135 		if (ISDIRDELIM(*str))
136 			return str - start;
137 		str++;
138 	}
139 	return -1;
140 }
141 
142 /*
143  * Extract zero terminated short name from a directory entry.
144  */
145 static void get_name (dir_entry *dirent, char *s_name)
146 {
147 	char *ptr;
148 
149 	memcpy(s_name, dirent->name, 8);
150 	s_name[8] = '\0';
151 	ptr = s_name;
152 	while (*ptr && *ptr != ' ')
153 		ptr++;
154 	if (dirent->ext[0] && dirent->ext[0] != ' ') {
155 		*ptr = '.';
156 		ptr++;
157 		memcpy(ptr, dirent->ext, 3);
158 		ptr[3] = '\0';
159 		while (*ptr && *ptr != ' ')
160 			ptr++;
161 	}
162 	*ptr = '\0';
163 	if (*s_name == DELETED_FLAG)
164 		*s_name = '\0';
165 	else if (*s_name == aRING)
166 		*s_name = DELETED_FLAG;
167 	downcase(s_name);
168 }
169 
170 /*
171  * Get the entry at index 'entry' in a FAT (12/16/32) table.
172  * On failure 0x00 is returned.
173  */
174 static __u32 get_fatent (fsdata *mydata, __u32 entry)
175 {
176 	__u32 bufnum;
177 	__u32 off16, offset;
178 	__u32 ret = 0x00;
179 	__u16 val1, val2;
180 
181 	switch (mydata->fatsize) {
182 	case 32:
183 		bufnum = entry / FAT32BUFSIZE;
184 		offset = entry - bufnum * FAT32BUFSIZE;
185 		break;
186 	case 16:
187 		bufnum = entry / FAT16BUFSIZE;
188 		offset = entry - bufnum * FAT16BUFSIZE;
189 		break;
190 	case 12:
191 		bufnum = entry / FAT12BUFSIZE;
192 		offset = entry - bufnum * FAT12BUFSIZE;
193 		break;
194 
195 	default:
196 		/* Unsupported FAT size */
197 		return ret;
198 	}
199 
200 	debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
201 	       mydata->fatsize, entry, entry, offset, offset);
202 
203 	/* Read a new block of FAT entries into the cache. */
204 	if (bufnum != mydata->fatbufnum) {
205 		__u32 getsize = FATBUFBLOCKS;
206 		__u8 *bufptr = mydata->fatbuf;
207 		__u32 fatlength = mydata->fatlength;
208 		__u32 startblock = bufnum * FATBUFBLOCKS;
209 
210 		if (getsize > fatlength)
211 			getsize = fatlength;
212 
213 		fatlength *= mydata->sect_size;	/* We want it in bytes now */
214 		startblock += mydata->fat_sect;	/* Offset from start of disk */
215 
216 		if (disk_read(startblock, getsize, bufptr) < 0) {
217 			debug("Error reading FAT blocks\n");
218 			return ret;
219 		}
220 		mydata->fatbufnum = bufnum;
221 	}
222 
223 	/* Get the actual entry from the table */
224 	switch (mydata->fatsize) {
225 	case 32:
226 		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
227 		break;
228 	case 16:
229 		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
230 		break;
231 	case 12:
232 		off16 = (offset * 3) / 4;
233 
234 		switch (offset & 0x3) {
235 		case 0:
236 			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
237 			ret &= 0xfff;
238 			break;
239 		case 1:
240 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
241 			val1 &= 0xf000;
242 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
243 			val2 &= 0x00ff;
244 			ret = (val2 << 4) | (val1 >> 12);
245 			break;
246 		case 2:
247 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
248 			val1 &= 0xff00;
249 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
250 			val2 &= 0x000f;
251 			ret = (val2 << 8) | (val1 >> 8);
252 			break;
253 		case 3:
254 			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
255 			ret = (ret & 0xfff0) >> 4;
256 			break;
257 		default:
258 			break;
259 		}
260 		break;
261 	}
262 	debug("FAT%d: ret: %08x, offset: %04x\n",
263 	       mydata->fatsize, ret, offset);
264 
265 	return ret;
266 }
267 
268 /*
269  * Read at most 'size' bytes from the specified cluster into 'buffer'.
270  * Return 0 on success, -1 otherwise.
271  */
272 static int
273 get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
274 	     unsigned long size)
275 {
276 	__u32 idx = 0;
277 	__u32 startsect;
278 	__u32 nr_sect;
279 	int ret;
280 
281 	if (clustnum > 0) {
282 		startsect = mydata->data_begin +
283 				clustnum * mydata->clust_size;
284 	} else {
285 		startsect = mydata->rootdir_sect;
286 	}
287 
288 	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
289 
290 	nr_sect = size / mydata->sect_size;
291 	ret = disk_read(startsect, nr_sect, buffer);
292 	if (ret != nr_sect) {
293 		debug("Error reading data (got %d)\n", ret);
294 		return -1;
295 	}
296 	if (size % mydata->sect_size) {
297 		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
298 
299 		idx = size / mydata->sect_size;
300 		ret = disk_read(startsect + idx, 1, tmpbuf);
301 		if (ret != 1) {
302 			debug("Error reading data (got %d)\n", ret);
303 			return -1;
304 		}
305 		buffer += idx * mydata->sect_size;
306 
307 		memcpy(buffer, tmpbuf, size % mydata->sect_size);
308 		return 0;
309 	}
310 
311 	return 0;
312 }
313 
314 /*
315  * Read at most 'maxsize' bytes from the file associated with 'dentptr'
316  * into 'buffer'.
317  * Return the number of bytes read or -1 on fatal errors.
318  */
319 static long
320 get_contents (fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
321 	      unsigned long maxsize)
322 {
323 	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
324 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
325 	__u32 curclust = START(dentptr);
326 	__u32 endclust, newclust;
327 	unsigned long actsize;
328 
329 	debug("Filesize: %ld bytes\n", filesize);
330 
331 	if (maxsize > 0 && filesize > maxsize)
332 		filesize = maxsize;
333 
334 	debug("%ld bytes\n", filesize);
335 
336 	actsize = bytesperclust;
337 	endclust = curclust;
338 
339 	do {
340 		/* search for consecutive clusters */
341 		while (actsize < filesize) {
342 			newclust = get_fatent(mydata, endclust);
343 			if ((newclust - 1) != endclust)
344 				goto getit;
345 			if (CHECK_CLUST(newclust, mydata->fatsize)) {
346 				debug("curclust: 0x%x\n", newclust);
347 				debug("Invalid FAT entry\n");
348 				return gotsize;
349 			}
350 			endclust = newclust;
351 			actsize += bytesperclust;
352 		}
353 
354 		/* actsize >= file size */
355 		actsize -= bytesperclust;
356 
357 		/* get remaining clusters */
358 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
359 			printf("Error reading cluster\n");
360 			return -1;
361 		}
362 
363 		/* get remaining bytes */
364 		gotsize += (int)actsize;
365 		filesize -= actsize;
366 		buffer += actsize;
367 		actsize = filesize;
368 		if (get_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
369 			printf("Error reading cluster\n");
370 			return -1;
371 		}
372 		gotsize += actsize;
373 		return gotsize;
374 getit:
375 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
376 			printf("Error reading cluster\n");
377 			return -1;
378 		}
379 		gotsize += (int)actsize;
380 		filesize -= actsize;
381 		buffer += actsize;
382 
383 		curclust = get_fatent(mydata, endclust);
384 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
385 			debug("curclust: 0x%x\n", curclust);
386 			printf("Invalid FAT entry\n");
387 			return gotsize;
388 		}
389 		actsize = bytesperclust;
390 		endclust = curclust;
391 	} while (1);
392 }
393 
394 #ifdef CONFIG_SUPPORT_VFAT
395 /*
396  * Extract the file name information from 'slotptr' into 'l_name',
397  * starting at l_name[*idx].
398  * Return 1 if terminator (zero byte) is found, 0 otherwise.
399  */
400 static int slot2str (dir_slot *slotptr, char *l_name, int *idx)
401 {
402 	int j;
403 
404 	for (j = 0; j <= 8; j += 2) {
405 		l_name[*idx] = slotptr->name0_4[j];
406 		if (l_name[*idx] == 0x00)
407 			return 1;
408 		(*idx)++;
409 	}
410 	for (j = 0; j <= 10; j += 2) {
411 		l_name[*idx] = slotptr->name5_10[j];
412 		if (l_name[*idx] == 0x00)
413 			return 1;
414 		(*idx)++;
415 	}
416 	for (j = 0; j <= 2; j += 2) {
417 		l_name[*idx] = slotptr->name11_12[j];
418 		if (l_name[*idx] == 0x00)
419 			return 1;
420 		(*idx)++;
421 	}
422 
423 	return 0;
424 }
425 
426 /*
427  * Extract the full long filename starting at 'retdent' (which is really
428  * a slot) into 'l_name'. If successful also copy the real directory entry
429  * into 'retdent'
430  * Return 0 on success, -1 otherwise.
431  */
432 __u8 get_vfatname_block[MAX_CLUSTSIZE]
433 	__aligned(ARCH_DMA_MINALIGN);
434 
435 static int
436 get_vfatname (fsdata *mydata, int curclust, __u8 *cluster,
437 	      dir_entry *retdent, char *l_name)
438 {
439 	dir_entry *realdent;
440 	dir_slot *slotptr = (dir_slot *)retdent;
441 	__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
442 							PREFETCH_BLOCKS :
443 							mydata->clust_size);
444 	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
445 	int idx = 0;
446 
447 	if (counter > VFAT_MAXSEQ) {
448 		debug("Error: VFAT name is too long\n");
449 		return -1;
450 	}
451 
452 	while ((__u8 *)slotptr < buflimit) {
453 		if (counter == 0)
454 			break;
455 		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
456 			return -1;
457 		slotptr++;
458 		counter--;
459 	}
460 
461 	if ((__u8 *)slotptr >= buflimit) {
462 		dir_slot *slotptr2;
463 
464 		if (curclust == 0)
465 			return -1;
466 		curclust = get_fatent(mydata, curclust);
467 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
468 			debug("curclust: 0x%x\n", curclust);
469 			printf("Invalid FAT entry\n");
470 			return -1;
471 		}
472 
473 		if (get_cluster(mydata, curclust, get_vfatname_block,
474 				mydata->clust_size * mydata->sect_size) != 0) {
475 			debug("Error: reading directory block\n");
476 			return -1;
477 		}
478 
479 		slotptr2 = (dir_slot *)get_vfatname_block;
480 		while (counter > 0) {
481 			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
482 			    & 0xff) != counter)
483 				return -1;
484 			slotptr2++;
485 			counter--;
486 		}
487 
488 		/* Save the real directory entry */
489 		realdent = (dir_entry *)slotptr2;
490 		while ((__u8 *)slotptr2 > get_vfatname_block) {
491 			slotptr2--;
492 			slot2str(slotptr2, l_name, &idx);
493 		}
494 	} else {
495 		/* Save the real directory entry */
496 		realdent = (dir_entry *)slotptr;
497 	}
498 
499 	do {
500 		slotptr--;
501 		if (slot2str(slotptr, l_name, &idx))
502 			break;
503 	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
504 
505 	l_name[idx] = '\0';
506 	if (*l_name == DELETED_FLAG)
507 		*l_name = '\0';
508 	else if (*l_name == aRING)
509 		*l_name = DELETED_FLAG;
510 	downcase(l_name);
511 
512 	/* Return the real directory entry */
513 	memcpy(retdent, realdent, sizeof(dir_entry));
514 
515 	return 0;
516 }
517 
518 /* Calculate short name checksum */
519 static __u8 mkcksum (const char *str)
520 {
521 	int i;
522 
523 	__u8 ret = 0;
524 
525 	for (i = 0; i < 11; i++) {
526 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
527 	}
528 
529 	return ret;
530 }
531 #endif	/* CONFIG_SUPPORT_VFAT */
532 
533 /*
534  * Get the directory entry associated with 'filename' from the directory
535  * starting at 'startsect'
536  */
537 __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
538 	__aligned(ARCH_DMA_MINALIGN);
539 
540 static dir_entry *get_dentfromdir (fsdata *mydata, int startsect,
541 				   char *filename, dir_entry *retdent,
542 				   int dols)
543 {
544 	__u16 prevcksum = 0xffff;
545 	__u32 curclust = START(retdent);
546 	int files = 0, dirs = 0;
547 
548 	debug("get_dentfromdir: %s\n", filename);
549 
550 	while (1) {
551 		dir_entry *dentptr;
552 
553 		int i;
554 
555 		if (get_cluster(mydata, curclust, get_dentfromdir_block,
556 				mydata->clust_size * mydata->sect_size) != 0) {
557 			debug("Error: reading directory block\n");
558 			return NULL;
559 		}
560 
561 		dentptr = (dir_entry *)get_dentfromdir_block;
562 
563 		for (i = 0; i < DIRENTSPERCLUST; i++) {
564 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
565 
566 			l_name[0] = '\0';
567 			if (dentptr->name[0] == DELETED_FLAG) {
568 				dentptr++;
569 				continue;
570 			}
571 			if ((dentptr->attr & ATTR_VOLUME)) {
572 #ifdef CONFIG_SUPPORT_VFAT
573 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
574 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
575 					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
576 					get_vfatname(mydata, curclust,
577 						     get_dentfromdir_block,
578 						     dentptr, l_name);
579 					if (dols) {
580 						int isdir;
581 						char dirc;
582 						int doit = 0;
583 
584 						isdir = (dentptr->attr & ATTR_DIR);
585 
586 						if (isdir) {
587 							dirs++;
588 							dirc = '/';
589 							doit = 1;
590 						} else {
591 							dirc = ' ';
592 							if (l_name[0] != 0) {
593 								files++;
594 								doit = 1;
595 							}
596 						}
597 						if (doit) {
598 							if (dirc == ' ') {
599 								printf(" %8ld   %s%c\n",
600 									(long)FAT2CPU32(dentptr->size),
601 									l_name,
602 									dirc);
603 							} else {
604 								printf("            %s%c\n",
605 									l_name,
606 									dirc);
607 							}
608 						}
609 						dentptr++;
610 						continue;
611 					}
612 					debug("vfatname: |%s|\n", l_name);
613 				} else
614 #endif
615 				{
616 					/* Volume label or VFAT entry */
617 					dentptr++;
618 					continue;
619 				}
620 			}
621 			if (dentptr->name[0] == 0) {
622 				if (dols) {
623 					printf("\n%d file(s), %d dir(s)\n\n",
624 						files, dirs);
625 				}
626 				debug("Dentname == NULL - %d\n", i);
627 				return NULL;
628 			}
629 #ifdef CONFIG_SUPPORT_VFAT
630 			if (dols && mkcksum(dentptr->name) == prevcksum) {
631 				prevcksum = 0xffff;
632 				dentptr++;
633 				continue;
634 			}
635 #endif
636 			get_name(dentptr, s_name);
637 			if (dols) {
638 				int isdir = (dentptr->attr & ATTR_DIR);
639 				char dirc;
640 				int doit = 0;
641 
642 				if (isdir) {
643 					dirs++;
644 					dirc = '/';
645 					doit = 1;
646 				} else {
647 					dirc = ' ';
648 					if (s_name[0] != 0) {
649 						files++;
650 						doit = 1;
651 					}
652 				}
653 
654 				if (doit) {
655 					if (dirc == ' ') {
656 						printf(" %8ld   %s%c\n",
657 							(long)FAT2CPU32(dentptr->size),
658 							s_name, dirc);
659 					} else {
660 						printf("            %s%c\n",
661 							s_name, dirc);
662 					}
663 				}
664 
665 				dentptr++;
666 				continue;
667 			}
668 
669 			if (strcmp(filename, s_name)
670 			    && strcmp(filename, l_name)) {
671 				debug("Mismatch: |%s|%s|\n", s_name, l_name);
672 				dentptr++;
673 				continue;
674 			}
675 
676 			memcpy(retdent, dentptr, sizeof(dir_entry));
677 
678 			debug("DentName: %s", s_name);
679 			debug(", start: 0x%x", START(dentptr));
680 			debug(", size:  0x%x %s\n",
681 			      FAT2CPU32(dentptr->size),
682 			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
683 
684 			return retdent;
685 		}
686 
687 		curclust = get_fatent(mydata, curclust);
688 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
689 			debug("curclust: 0x%x\n", curclust);
690 			printf("Invalid FAT entry\n");
691 			return NULL;
692 		}
693 	}
694 
695 	return NULL;
696 }
697 
698 /*
699  * Read boot sector and volume info from a FAT filesystem
700  */
701 static int
702 read_bootsectandvi (boot_sector *bs, volume_info *volinfo, int *fatsize)
703 {
704 	__u8 *block;
705 	volume_info *vistart;
706 	int ret = 0;
707 
708 	if (cur_dev == NULL) {
709 		debug("Error: no device selected\n");
710 		return -1;
711 	}
712 
713 	block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
714 	if (block == NULL) {
715 		debug("Error: allocating block\n");
716 		return -1;
717 	}
718 
719 	if (disk_read (0, 1, block) < 0) {
720 		debug("Error: reading block\n");
721 		goto fail;
722 	}
723 
724 	memcpy(bs, block, sizeof(boot_sector));
725 	bs->reserved = FAT2CPU16(bs->reserved);
726 	bs->fat_length = FAT2CPU16(bs->fat_length);
727 	bs->secs_track = FAT2CPU16(bs->secs_track);
728 	bs->heads = FAT2CPU16(bs->heads);
729 	bs->total_sect = FAT2CPU32(bs->total_sect);
730 
731 	/* FAT32 entries */
732 	if (bs->fat_length == 0) {
733 		/* Assume FAT32 */
734 		bs->fat32_length = FAT2CPU32(bs->fat32_length);
735 		bs->flags = FAT2CPU16(bs->flags);
736 		bs->root_cluster = FAT2CPU32(bs->root_cluster);
737 		bs->info_sector = FAT2CPU16(bs->info_sector);
738 		bs->backup_boot = FAT2CPU16(bs->backup_boot);
739 		vistart = (volume_info *)(block + sizeof(boot_sector));
740 		*fatsize = 32;
741 	} else {
742 		vistart = (volume_info *)&(bs->fat32_length);
743 		*fatsize = 0;
744 	}
745 	memcpy(volinfo, vistart, sizeof(volume_info));
746 
747 	if (*fatsize == 32) {
748 		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
749 			goto exit;
750 	} else {
751 		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
752 			*fatsize = 12;
753 			goto exit;
754 		}
755 		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
756 			*fatsize = 16;
757 			goto exit;
758 		}
759 	}
760 
761 	debug("Error: broken fs_type sign\n");
762 fail:
763 	ret = -1;
764 exit:
765 	free(block);
766 	return ret;
767 }
768 
769 __u8 do_fat_read_block[MAX_CLUSTSIZE]
770 	__aligned(ARCH_DMA_MINALIGN);
771 
772 long
773 do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
774 	     int dols)
775 {
776 	char fnamecopy[2048];
777 	boot_sector bs;
778 	volume_info volinfo;
779 	fsdata datablock;
780 	fsdata *mydata = &datablock;
781 	dir_entry *dentptr;
782 	__u16 prevcksum = 0xffff;
783 	char *subname = "";
784 	__u32 cursect;
785 	int idx, isdir = 0;
786 	int files = 0, dirs = 0;
787 	long ret = -1;
788 	int firsttime;
789 	__u32 root_cluster = 0;
790 	int rootdir_size = 0;
791 	int j;
792 
793 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
794 		debug("Error: reading boot sector\n");
795 		return -1;
796 	}
797 
798 	if (mydata->fatsize == 32) {
799 		root_cluster = bs.root_cluster;
800 		mydata->fatlength = bs.fat32_length;
801 	} else {
802 		mydata->fatlength = bs.fat_length;
803 	}
804 
805 	mydata->fat_sect = bs.reserved;
806 
807 	cursect = mydata->rootdir_sect
808 		= mydata->fat_sect + mydata->fatlength * bs.fats;
809 
810 	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
811 	mydata->clust_size = bs.cluster_size;
812 	if (mydata->sect_size != cur_part_info.blksz) {
813 		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
814 				mydata->sect_size, cur_part_info.blksz);
815 		return -1;
816 	}
817 
818 	if (mydata->fatsize == 32) {
819 		mydata->data_begin = mydata->rootdir_sect -
820 					(mydata->clust_size * 2);
821 	} else {
822 		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
823 				 bs.dir_entries[0]) *
824 				 sizeof(dir_entry)) /
825 				 mydata->sect_size;
826 		mydata->data_begin = mydata->rootdir_sect +
827 					rootdir_size -
828 					(mydata->clust_size * 2);
829 	}
830 
831 	mydata->fatbufnum = -1;
832 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
833 	if (mydata->fatbuf == NULL) {
834 		debug("Error: allocating memory\n");
835 		return -1;
836 	}
837 
838 #ifdef CONFIG_SUPPORT_VFAT
839 	debug("VFAT Support enabled\n");
840 #endif
841 	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
842 	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
843 	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
844 	       "Data begins at: %d\n",
845 	       root_cluster,
846 	       mydata->rootdir_sect,
847 	       mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
848 	debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
849 	      mydata->clust_size);
850 
851 	/* "cwd" is always the root... */
852 	while (ISDIRDELIM(*filename))
853 		filename++;
854 
855 	/* Make a copy of the filename and convert it to lowercase */
856 	strcpy(fnamecopy, filename);
857 	downcase(fnamecopy);
858 
859 	if (*fnamecopy == '\0') {
860 		if (!dols)
861 			goto exit;
862 
863 		dols = LS_ROOT;
864 	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
865 		isdir = 1;
866 		fnamecopy[idx] = '\0';
867 		subname = fnamecopy + idx + 1;
868 
869 		/* Handle multiple delimiters */
870 		while (ISDIRDELIM(*subname))
871 			subname++;
872 	} else if (dols) {
873 		isdir = 1;
874 	}
875 
876 	j = 0;
877 	while (1) {
878 		int i;
879 
880 		debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%zd\n",
881 			cursect, mydata->clust_size, DIRENTSPERBLOCK);
882 
883 		if (disk_read(cursect,
884 				(mydata->fatsize == 32) ?
885 				(mydata->clust_size) :
886 				PREFETCH_BLOCKS,
887 				do_fat_read_block) < 0) {
888 			debug("Error: reading rootdir block\n");
889 			goto exit;
890 		}
891 
892 		dentptr = (dir_entry *) do_fat_read_block;
893 
894 		for (i = 0; i < DIRENTSPERBLOCK; i++) {
895 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
896 
897 			l_name[0] = '\0';
898 			if (dentptr->name[0] == DELETED_FLAG) {
899 				dentptr++;
900 				continue;
901 			}
902 			if ((dentptr->attr & ATTR_VOLUME)) {
903 #ifdef CONFIG_SUPPORT_VFAT
904 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
905 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
906 					prevcksum =
907 						((dir_slot *)dentptr)->alias_checksum;
908 
909 					get_vfatname(mydata,
910 						     root_cluster,
911 						     do_fat_read_block,
912 						     dentptr, l_name);
913 
914 					if (dols == LS_ROOT) {
915 						char dirc;
916 						int doit = 0;
917 						int isdir =
918 							(dentptr->attr & ATTR_DIR);
919 
920 						if (isdir) {
921 							dirs++;
922 							dirc = '/';
923 							doit = 1;
924 						} else {
925 							dirc = ' ';
926 							if (l_name[0] != 0) {
927 								files++;
928 								doit = 1;
929 							}
930 						}
931 						if (doit) {
932 							if (dirc == ' ') {
933 								printf(" %8ld   %s%c\n",
934 									(long)FAT2CPU32(dentptr->size),
935 									l_name,
936 									dirc);
937 							} else {
938 								printf("            %s%c\n",
939 									l_name,
940 									dirc);
941 							}
942 						}
943 						dentptr++;
944 						continue;
945 					}
946 					debug("Rootvfatname: |%s|\n",
947 					       l_name);
948 				} else
949 #endif
950 				{
951 					/* Volume label or VFAT entry */
952 					dentptr++;
953 					continue;
954 				}
955 			} else if (dentptr->name[0] == 0) {
956 				debug("RootDentname == NULL - %d\n", i);
957 				if (dols == LS_ROOT) {
958 					printf("\n%d file(s), %d dir(s)\n\n",
959 						files, dirs);
960 					ret = 0;
961 				}
962 				goto exit;
963 			}
964 #ifdef CONFIG_SUPPORT_VFAT
965 			else if (dols == LS_ROOT &&
966 				 mkcksum(dentptr->name) == prevcksum) {
967 				prevcksum = 0xffff;
968 				dentptr++;
969 				continue;
970 			}
971 #endif
972 			get_name(dentptr, s_name);
973 
974 			if (dols == LS_ROOT) {
975 				int isdir = (dentptr->attr & ATTR_DIR);
976 				char dirc;
977 				int doit = 0;
978 
979 				if (isdir) {
980 					dirc = '/';
981 					if (s_name[0] != 0) {
982 						dirs++;
983 						doit = 1;
984 					}
985 				} else {
986 					dirc = ' ';
987 					if (s_name[0] != 0) {
988 						files++;
989 						doit = 1;
990 					}
991 				}
992 				if (doit) {
993 					if (dirc == ' ') {
994 						printf(" %8ld   %s%c\n",
995 							(long)FAT2CPU32(dentptr->size),
996 							s_name, dirc);
997 					} else {
998 						printf("            %s%c\n",
999 							s_name, dirc);
1000 					}
1001 				}
1002 				dentptr++;
1003 				continue;
1004 			}
1005 
1006 			if (strcmp(fnamecopy, s_name)
1007 			    && strcmp(fnamecopy, l_name)) {
1008 				debug("RootMismatch: |%s|%s|\n", s_name,
1009 				       l_name);
1010 				dentptr++;
1011 				continue;
1012 			}
1013 
1014 			if (isdir && !(dentptr->attr & ATTR_DIR))
1015 				goto exit;
1016 
1017 			debug("RootName: %s", s_name);
1018 			debug(", start: 0x%x", START(dentptr));
1019 			debug(", size:  0x%x %s\n",
1020 			       FAT2CPU32(dentptr->size),
1021 			       isdir ? "(DIR)" : "");
1022 
1023 			goto rootdir_done;	/* We got a match */
1024 		}
1025 		debug("END LOOP: j=%d   clust_size=%d\n", j,
1026 		       mydata->clust_size);
1027 
1028 		/*
1029 		 * On FAT32 we must fetch the FAT entries for the next
1030 		 * root directory clusters when a cluster has been
1031 		 * completely processed.
1032 		 */
1033 		++j;
1034 		int fat32_end = 0;
1035 		if ((mydata->fatsize == 32) && (j == mydata->clust_size)) {
1036 			int nxtsect = 0;
1037 			int nxt_clust = 0;
1038 
1039 			nxt_clust = get_fatent(mydata, root_cluster);
1040 			fat32_end = CHECK_CLUST(nxt_clust, 32);
1041 
1042 			nxtsect = mydata->data_begin +
1043 				(nxt_clust * mydata->clust_size);
1044 
1045 			root_cluster = nxt_clust;
1046 
1047 			cursect = nxtsect;
1048 			j = 0;
1049 		} else {
1050 			cursect++;
1051 		}
1052 
1053 		/* If end of rootdir reached */
1054 		if ((mydata->fatsize == 32 && fat32_end) ||
1055 		    (mydata->fatsize != 32 && j == rootdir_size)) {
1056 			if (dols == LS_ROOT) {
1057 				printf("\n%d file(s), %d dir(s)\n\n",
1058 				       files, dirs);
1059 				ret = 0;
1060 			}
1061 			goto exit;
1062 		}
1063 	}
1064 rootdir_done:
1065 
1066 	firsttime = 1;
1067 
1068 	while (isdir) {
1069 		int startsect = mydata->data_begin
1070 			+ START(dentptr) * mydata->clust_size;
1071 		dir_entry dent;
1072 		char *nextname = NULL;
1073 
1074 		dent = *dentptr;
1075 		dentptr = &dent;
1076 
1077 		idx = dirdelim(subname);
1078 
1079 		if (idx >= 0) {
1080 			subname[idx] = '\0';
1081 			nextname = subname + idx + 1;
1082 			/* Handle multiple delimiters */
1083 			while (ISDIRDELIM(*nextname))
1084 				nextname++;
1085 			if (dols && *nextname == '\0')
1086 				firsttime = 0;
1087 		} else {
1088 			if (dols && firsttime) {
1089 				firsttime = 0;
1090 			} else {
1091 				isdir = 0;
1092 			}
1093 		}
1094 
1095 		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1096 				     isdir ? 0 : dols) == NULL) {
1097 			if (dols && !isdir)
1098 				ret = 0;
1099 			goto exit;
1100 		}
1101 
1102 		if (idx >= 0) {
1103 			if (!(dentptr->attr & ATTR_DIR))
1104 				goto exit;
1105 			subname = nextname;
1106 		}
1107 	}
1108 
1109 	ret = get_contents(mydata, dentptr, buffer, maxsize);
1110 	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
1111 
1112 exit:
1113 	free(mydata->fatbuf);
1114 	return ret;
1115 }
1116 
1117 int file_fat_detectfs (void)
1118 {
1119 	boot_sector bs;
1120 	volume_info volinfo;
1121 	int fatsize;
1122 	char vol_label[12];
1123 
1124 	if (cur_dev == NULL) {
1125 		printf("No current device\n");
1126 		return 1;
1127 	}
1128 
1129 #if defined(CONFIG_CMD_IDE) || \
1130     defined(CONFIG_CMD_SATA) || \
1131     defined(CONFIG_CMD_SCSI) || \
1132     defined(CONFIG_CMD_USB) || \
1133     defined(CONFIG_MMC)
1134 	printf("Interface:  ");
1135 	switch (cur_dev->if_type) {
1136 	case IF_TYPE_IDE:
1137 		printf("IDE");
1138 		break;
1139 	case IF_TYPE_SATA:
1140 		printf("SATA");
1141 		break;
1142 	case IF_TYPE_SCSI:
1143 		printf("SCSI");
1144 		break;
1145 	case IF_TYPE_ATAPI:
1146 		printf("ATAPI");
1147 		break;
1148 	case IF_TYPE_USB:
1149 		printf("USB");
1150 		break;
1151 	case IF_TYPE_DOC:
1152 		printf("DOC");
1153 		break;
1154 	case IF_TYPE_MMC:
1155 		printf("MMC");
1156 		break;
1157 	default:
1158 		printf("Unknown");
1159 	}
1160 
1161 	printf("\n  Device %d: ", cur_dev->dev);
1162 	dev_print(cur_dev);
1163 #endif
1164 
1165 	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1166 		printf("\nNo valid FAT fs found\n");
1167 		return 1;
1168 	}
1169 
1170 	memcpy(vol_label, volinfo.volume_label, 11);
1171 	vol_label[11] = '\0';
1172 	volinfo.fs_type[5] = '\0';
1173 
1174 	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part_nr,
1175 		volinfo.fs_type, vol_label);
1176 
1177 	return 0;
1178 }
1179 
1180 int file_fat_ls (const char *dir)
1181 {
1182 	return do_fat_read(dir, NULL, 0, LS_YES);
1183 }
1184 
1185 long file_fat_read (const char *filename, void *buffer, unsigned long maxsize)
1186 {
1187 	printf("reading %s\n", filename);
1188 	return do_fat_read(filename, buffer, maxsize, LS_NO);
1189 }
1190