xref: /openbmc/u-boot/fs/fat/fat.c (revision a2ac1b3a)
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 != 0) {
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 (startblock + getsize > fatlength)
211 			getsize = fatlength - startblock;
212 
213 		startblock += mydata->fat_sect;	/* Offset from start of disk */
214 
215 		if (disk_read(startblock, getsize, bufptr) < 0) {
216 			debug("Error reading FAT blocks\n");
217 			return ret;
218 		}
219 		mydata->fatbufnum = bufnum;
220 	}
221 
222 	/* Get the actual entry from the table */
223 	switch (mydata->fatsize) {
224 	case 32:
225 		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
226 		break;
227 	case 16:
228 		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
229 		break;
230 	case 12:
231 		off16 = (offset * 3) / 4;
232 
233 		switch (offset & 0x3) {
234 		case 0:
235 			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
236 			ret &= 0xfff;
237 			break;
238 		case 1:
239 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
240 			val1 &= 0xf000;
241 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
242 			val2 &= 0x00ff;
243 			ret = (val2 << 4) | (val1 >> 12);
244 			break;
245 		case 2:
246 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
247 			val1 &= 0xff00;
248 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
249 			val2 &= 0x000f;
250 			ret = (val2 << 8) | (val1 >> 8);
251 			break;
252 		case 3:
253 			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
254 			ret = (ret & 0xfff0) >> 4;
255 			break;
256 		default:
257 			break;
258 		}
259 		break;
260 	}
261 	debug("FAT%d: ret: %08x, offset: %04x\n",
262 	       mydata->fatsize, ret, offset);
263 
264 	return ret;
265 }
266 
267 /*
268  * Read at most 'size' bytes from the specified cluster into 'buffer'.
269  * Return 0 on success, -1 otherwise.
270  */
271 static int
272 get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
273 {
274 	__u32 idx = 0;
275 	__u32 startsect;
276 	int ret;
277 
278 	if (clustnum > 0) {
279 		startsect = mydata->data_begin +
280 				clustnum * mydata->clust_size;
281 	} else {
282 		startsect = mydata->rootdir_sect;
283 	}
284 
285 	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
286 
287 	if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
288 		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
289 
290 		printf("FAT: Misaligned buffer address (%p)\n", buffer);
291 
292 		while (size >= mydata->sect_size) {
293 			ret = disk_read(startsect++, 1, tmpbuf);
294 			if (ret != 1) {
295 				debug("Error reading data (got %d)\n", ret);
296 				return -1;
297 			}
298 
299 			memcpy(buffer, tmpbuf, mydata->sect_size);
300 			buffer += mydata->sect_size;
301 			size -= mydata->sect_size;
302 		}
303 	} else {
304 		idx = size / mydata->sect_size;
305 		ret = disk_read(startsect, idx, buffer);
306 		if (ret != idx) {
307 			debug("Error reading data (got %d)\n", ret);
308 			return -1;
309 		}
310 		startsect += idx;
311 		idx *= mydata->sect_size;
312 		buffer += idx;
313 		size -= idx;
314 	}
315 	if (size) {
316 		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
317 
318 		ret = disk_read(startsect, 1, tmpbuf);
319 		if (ret != 1) {
320 			debug("Error reading data (got %d)\n", ret);
321 			return -1;
322 		}
323 
324 		memcpy(buffer, tmpbuf, size);
325 	}
326 
327 	return 0;
328 }
329 
330 /*
331  * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
332  * into 'buffer'.
333  * Return the number of bytes read or -1 on fatal errors.
334  */
335 __u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
336 	__aligned(ARCH_DMA_MINALIGN);
337 
338 static long
339 get_contents(fsdata *mydata, dir_entry *dentptr, unsigned long pos,
340 	     __u8 *buffer, unsigned long maxsize)
341 {
342 	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
343 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
344 	__u32 curclust = START(dentptr);
345 	__u32 endclust, newclust;
346 	unsigned long actsize;
347 
348 	debug("Filesize: %ld bytes\n", filesize);
349 
350 	if (pos >= filesize) {
351 		debug("Read position past EOF: %lu\n", pos);
352 		return gotsize;
353 	}
354 
355 	if (maxsize > 0 && filesize > pos + maxsize)
356 		filesize = pos + maxsize;
357 
358 	debug("%ld bytes\n", filesize);
359 
360 	actsize = bytesperclust;
361 
362 	/* go to cluster at pos */
363 	while (actsize <= pos) {
364 		curclust = get_fatent(mydata, curclust);
365 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
366 			debug("curclust: 0x%x\n", curclust);
367 			debug("Invalid FAT entry\n");
368 			return gotsize;
369 		}
370 		actsize += bytesperclust;
371 	}
372 
373 	/* actsize > pos */
374 	actsize -= bytesperclust;
375 	filesize -= actsize;
376 	pos -= actsize;
377 
378 	/* align to beginning of next cluster if any */
379 	if (pos) {
380 		actsize = min(filesize, bytesperclust);
381 		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
382 				(int)actsize) != 0) {
383 			printf("Error reading cluster\n");
384 			return -1;
385 		}
386 		filesize -= actsize;
387 		actsize -= pos;
388 		memcpy(buffer, get_contents_vfatname_block + pos, actsize);
389 		gotsize += actsize;
390 		if (!filesize)
391 			return gotsize;
392 		buffer += actsize;
393 
394 		curclust = get_fatent(mydata, curclust);
395 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
396 			debug("curclust: 0x%x\n", curclust);
397 			debug("Invalid FAT entry\n");
398 			return gotsize;
399 		}
400 	}
401 
402 	actsize = bytesperclust;
403 	endclust = curclust;
404 
405 	do {
406 		/* search for consecutive clusters */
407 		while (actsize < filesize) {
408 			newclust = get_fatent(mydata, endclust);
409 			if ((newclust - 1) != endclust)
410 				goto getit;
411 			if (CHECK_CLUST(newclust, mydata->fatsize)) {
412 				debug("curclust: 0x%x\n", newclust);
413 				debug("Invalid FAT entry\n");
414 				return gotsize;
415 			}
416 			endclust = newclust;
417 			actsize += bytesperclust;
418 		}
419 
420 		/* get remaining bytes */
421 		actsize = filesize;
422 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
423 			printf("Error reading cluster\n");
424 			return -1;
425 		}
426 		gotsize += actsize;
427 		return gotsize;
428 getit:
429 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
430 			printf("Error reading cluster\n");
431 			return -1;
432 		}
433 		gotsize += (int)actsize;
434 		filesize -= actsize;
435 		buffer += actsize;
436 
437 		curclust = get_fatent(mydata, endclust);
438 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
439 			debug("curclust: 0x%x\n", curclust);
440 			printf("Invalid FAT entry\n");
441 			return gotsize;
442 		}
443 		actsize = bytesperclust;
444 		endclust = curclust;
445 	} while (1);
446 }
447 
448 #ifdef CONFIG_SUPPORT_VFAT
449 /*
450  * Extract the file name information from 'slotptr' into 'l_name',
451  * starting at l_name[*idx].
452  * Return 1 if terminator (zero byte) is found, 0 otherwise.
453  */
454 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
455 {
456 	int j;
457 
458 	for (j = 0; j <= 8; j += 2) {
459 		l_name[*idx] = slotptr->name0_4[j];
460 		if (l_name[*idx] == 0x00)
461 			return 1;
462 		(*idx)++;
463 	}
464 	for (j = 0; j <= 10; j += 2) {
465 		l_name[*idx] = slotptr->name5_10[j];
466 		if (l_name[*idx] == 0x00)
467 			return 1;
468 		(*idx)++;
469 	}
470 	for (j = 0; j <= 2; j += 2) {
471 		l_name[*idx] = slotptr->name11_12[j];
472 		if (l_name[*idx] == 0x00)
473 			return 1;
474 		(*idx)++;
475 	}
476 
477 	return 0;
478 }
479 
480 /*
481  * Extract the full long filename starting at 'retdent' (which is really
482  * a slot) into 'l_name'. If successful also copy the real directory entry
483  * into 'retdent'
484  * Return 0 on success, -1 otherwise.
485  */
486 static int
487 get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
488 	     dir_entry *retdent, char *l_name)
489 {
490 	dir_entry *realdent;
491 	dir_slot *slotptr = (dir_slot *)retdent;
492 	__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
493 							PREFETCH_BLOCKS :
494 							mydata->clust_size);
495 	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
496 	int idx = 0;
497 
498 	if (counter > VFAT_MAXSEQ) {
499 		debug("Error: VFAT name is too long\n");
500 		return -1;
501 	}
502 
503 	while ((__u8 *)slotptr < buflimit) {
504 		if (counter == 0)
505 			break;
506 		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
507 			return -1;
508 		slotptr++;
509 		counter--;
510 	}
511 
512 	if ((__u8 *)slotptr >= buflimit) {
513 		dir_slot *slotptr2;
514 
515 		if (curclust == 0)
516 			return -1;
517 		curclust = get_fatent(mydata, curclust);
518 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
519 			debug("curclust: 0x%x\n", curclust);
520 			printf("Invalid FAT entry\n");
521 			return -1;
522 		}
523 
524 		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
525 				mydata->clust_size * mydata->sect_size) != 0) {
526 			debug("Error: reading directory block\n");
527 			return -1;
528 		}
529 
530 		slotptr2 = (dir_slot *)get_contents_vfatname_block;
531 		while (counter > 0) {
532 			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
533 			    & 0xff) != counter)
534 				return -1;
535 			slotptr2++;
536 			counter--;
537 		}
538 
539 		/* Save the real directory entry */
540 		realdent = (dir_entry *)slotptr2;
541 		while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
542 			slotptr2--;
543 			slot2str(slotptr2, l_name, &idx);
544 		}
545 	} else {
546 		/* Save the real directory entry */
547 		realdent = (dir_entry *)slotptr;
548 	}
549 
550 	do {
551 		slotptr--;
552 		if (slot2str(slotptr, l_name, &idx))
553 			break;
554 	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
555 
556 	l_name[idx] = '\0';
557 	if (*l_name == DELETED_FLAG)
558 		*l_name = '\0';
559 	else if (*l_name == aRING)
560 		*l_name = DELETED_FLAG;
561 	downcase(l_name);
562 
563 	/* Return the real directory entry */
564 	memcpy(retdent, realdent, sizeof(dir_entry));
565 
566 	return 0;
567 }
568 
569 /* Calculate short name checksum */
570 static __u8 mkcksum(const char *str)
571 {
572 	int i;
573 
574 	__u8 ret = 0;
575 
576 	for (i = 0; i < 11; i++) {
577 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
578 	}
579 
580 	return ret;
581 }
582 #endif	/* CONFIG_SUPPORT_VFAT */
583 
584 /*
585  * Get the directory entry associated with 'filename' from the directory
586  * starting at 'startsect'
587  */
588 __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
589 	__aligned(ARCH_DMA_MINALIGN);
590 
591 static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
592 				  char *filename, dir_entry *retdent,
593 				  int dols)
594 {
595 	__u16 prevcksum = 0xffff;
596 	__u32 curclust = START(retdent);
597 	int files = 0, dirs = 0;
598 
599 	debug("get_dentfromdir: %s\n", filename);
600 
601 	while (1) {
602 		dir_entry *dentptr;
603 
604 		int i;
605 
606 		if (get_cluster(mydata, curclust, get_dentfromdir_block,
607 				mydata->clust_size * mydata->sect_size) != 0) {
608 			debug("Error: reading directory block\n");
609 			return NULL;
610 		}
611 
612 		dentptr = (dir_entry *)get_dentfromdir_block;
613 
614 		for (i = 0; i < DIRENTSPERCLUST; i++) {
615 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
616 
617 			l_name[0] = '\0';
618 			if (dentptr->name[0] == DELETED_FLAG) {
619 				dentptr++;
620 				continue;
621 			}
622 			if ((dentptr->attr & ATTR_VOLUME)) {
623 #ifdef CONFIG_SUPPORT_VFAT
624 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
625 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
626 					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
627 					get_vfatname(mydata, curclust,
628 						     get_dentfromdir_block,
629 						     dentptr, l_name);
630 					if (dols) {
631 						int isdir;
632 						char dirc;
633 						int doit = 0;
634 
635 						isdir = (dentptr->attr & ATTR_DIR);
636 
637 						if (isdir) {
638 							dirs++;
639 							dirc = '/';
640 							doit = 1;
641 						} else {
642 							dirc = ' ';
643 							if (l_name[0] != 0) {
644 								files++;
645 								doit = 1;
646 							}
647 						}
648 						if (doit) {
649 							if (dirc == ' ') {
650 								printf(" %8ld   %s%c\n",
651 									(long)FAT2CPU32(dentptr->size),
652 									l_name,
653 									dirc);
654 							} else {
655 								printf("            %s%c\n",
656 									l_name,
657 									dirc);
658 							}
659 						}
660 						dentptr++;
661 						continue;
662 					}
663 					debug("vfatname: |%s|\n", l_name);
664 				} else
665 #endif
666 				{
667 					/* Volume label or VFAT entry */
668 					dentptr++;
669 					continue;
670 				}
671 			}
672 			if (dentptr->name[0] == 0) {
673 				if (dols) {
674 					printf("\n%d file(s), %d dir(s)\n\n",
675 						files, dirs);
676 				}
677 				debug("Dentname == NULL - %d\n", i);
678 				return NULL;
679 			}
680 #ifdef CONFIG_SUPPORT_VFAT
681 			if (dols && mkcksum(dentptr->name) == prevcksum) {
682 				prevcksum = 0xffff;
683 				dentptr++;
684 				continue;
685 			}
686 #endif
687 			get_name(dentptr, s_name);
688 			if (dols) {
689 				int isdir = (dentptr->attr & ATTR_DIR);
690 				char dirc;
691 				int doit = 0;
692 
693 				if (isdir) {
694 					dirs++;
695 					dirc = '/';
696 					doit = 1;
697 				} else {
698 					dirc = ' ';
699 					if (s_name[0] != 0) {
700 						files++;
701 						doit = 1;
702 					}
703 				}
704 
705 				if (doit) {
706 					if (dirc == ' ') {
707 						printf(" %8ld   %s%c\n",
708 							(long)FAT2CPU32(dentptr->size),
709 							s_name, dirc);
710 					} else {
711 						printf("            %s%c\n",
712 							s_name, dirc);
713 					}
714 				}
715 
716 				dentptr++;
717 				continue;
718 			}
719 
720 			if (strcmp(filename, s_name)
721 			    && strcmp(filename, l_name)) {
722 				debug("Mismatch: |%s|%s|\n", s_name, l_name);
723 				dentptr++;
724 				continue;
725 			}
726 
727 			memcpy(retdent, dentptr, sizeof(dir_entry));
728 
729 			debug("DentName: %s", s_name);
730 			debug(", start: 0x%x", START(dentptr));
731 			debug(", size:  0x%x %s\n",
732 			      FAT2CPU32(dentptr->size),
733 			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
734 
735 			return retdent;
736 		}
737 
738 		curclust = get_fatent(mydata, curclust);
739 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
740 			debug("curclust: 0x%x\n", curclust);
741 			printf("Invalid FAT entry\n");
742 			return NULL;
743 		}
744 	}
745 
746 	return NULL;
747 }
748 
749 /*
750  * Read boot sector and volume info from a FAT filesystem
751  */
752 static int
753 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
754 {
755 	__u8 *block;
756 	volume_info *vistart;
757 	int ret = 0;
758 
759 	if (cur_dev == NULL) {
760 		debug("Error: no device selected\n");
761 		return -1;
762 	}
763 
764 	block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
765 	if (block == NULL) {
766 		debug("Error: allocating block\n");
767 		return -1;
768 	}
769 
770 	if (disk_read(0, 1, block) < 0) {
771 		debug("Error: reading block\n");
772 		goto fail;
773 	}
774 
775 	memcpy(bs, block, sizeof(boot_sector));
776 	bs->reserved = FAT2CPU16(bs->reserved);
777 	bs->fat_length = FAT2CPU16(bs->fat_length);
778 	bs->secs_track = FAT2CPU16(bs->secs_track);
779 	bs->heads = FAT2CPU16(bs->heads);
780 	bs->total_sect = FAT2CPU32(bs->total_sect);
781 
782 	/* FAT32 entries */
783 	if (bs->fat_length == 0) {
784 		/* Assume FAT32 */
785 		bs->fat32_length = FAT2CPU32(bs->fat32_length);
786 		bs->flags = FAT2CPU16(bs->flags);
787 		bs->root_cluster = FAT2CPU32(bs->root_cluster);
788 		bs->info_sector = FAT2CPU16(bs->info_sector);
789 		bs->backup_boot = FAT2CPU16(bs->backup_boot);
790 		vistart = (volume_info *)(block + sizeof(boot_sector));
791 		*fatsize = 32;
792 	} else {
793 		vistart = (volume_info *)&(bs->fat32_length);
794 		*fatsize = 0;
795 	}
796 	memcpy(volinfo, vistart, sizeof(volume_info));
797 
798 	if (*fatsize == 32) {
799 		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
800 			goto exit;
801 	} else {
802 		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
803 			*fatsize = 12;
804 			goto exit;
805 		}
806 		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
807 			*fatsize = 16;
808 			goto exit;
809 		}
810 	}
811 
812 	debug("Error: broken fs_type sign\n");
813 fail:
814 	ret = -1;
815 exit:
816 	free(block);
817 	return ret;
818 }
819 
820 __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
821 	__aligned(ARCH_DMA_MINALIGN);
822 
823 long
824 do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
825 	       unsigned long maxsize, int dols)
826 {
827 	char fnamecopy[2048];
828 	boot_sector bs;
829 	volume_info volinfo;
830 	fsdata datablock;
831 	fsdata *mydata = &datablock;
832 	dir_entry *dentptr = NULL;
833 	__u16 prevcksum = 0xffff;
834 	char *subname = "";
835 	__u32 cursect;
836 	int idx, isdir = 0;
837 	int files = 0, dirs = 0;
838 	long ret = -1;
839 	int firsttime;
840 	__u32 root_cluster = 0;
841 	int rootdir_size = 0;
842 	int j;
843 
844 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
845 		debug("Error: reading boot sector\n");
846 		return -1;
847 	}
848 
849 	if (mydata->fatsize == 32) {
850 		root_cluster = bs.root_cluster;
851 		mydata->fatlength = bs.fat32_length;
852 	} else {
853 		mydata->fatlength = bs.fat_length;
854 	}
855 
856 	mydata->fat_sect = bs.reserved;
857 
858 	cursect = mydata->rootdir_sect
859 		= mydata->fat_sect + mydata->fatlength * bs.fats;
860 
861 	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
862 	mydata->clust_size = bs.cluster_size;
863 	if (mydata->sect_size != cur_part_info.blksz) {
864 		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
865 				mydata->sect_size, cur_part_info.blksz);
866 		return -1;
867 	}
868 
869 	if (mydata->fatsize == 32) {
870 		mydata->data_begin = mydata->rootdir_sect -
871 					(mydata->clust_size * 2);
872 	} else {
873 		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
874 				 bs.dir_entries[0]) *
875 				 sizeof(dir_entry)) /
876 				 mydata->sect_size;
877 		mydata->data_begin = mydata->rootdir_sect +
878 					rootdir_size -
879 					(mydata->clust_size * 2);
880 	}
881 
882 	mydata->fatbufnum = -1;
883 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
884 	if (mydata->fatbuf == NULL) {
885 		debug("Error: allocating memory\n");
886 		return -1;
887 	}
888 
889 #ifdef CONFIG_SUPPORT_VFAT
890 	debug("VFAT Support enabled\n");
891 #endif
892 	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
893 	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
894 	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
895 	       "Data begins at: %d\n",
896 	       root_cluster,
897 	       mydata->rootdir_sect,
898 	       mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
899 	debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
900 	      mydata->clust_size);
901 
902 	/* "cwd" is always the root... */
903 	while (ISDIRDELIM(*filename))
904 		filename++;
905 
906 	/* Make a copy of the filename and convert it to lowercase */
907 	strcpy(fnamecopy, filename);
908 	downcase(fnamecopy);
909 
910 	if (*fnamecopy == '\0') {
911 		if (!dols)
912 			goto exit;
913 
914 		dols = LS_ROOT;
915 	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
916 		isdir = 1;
917 		fnamecopy[idx] = '\0';
918 		subname = fnamecopy + idx + 1;
919 
920 		/* Handle multiple delimiters */
921 		while (ISDIRDELIM(*subname))
922 			subname++;
923 	} else if (dols) {
924 		isdir = 1;
925 	}
926 
927 	j = 0;
928 	while (1) {
929 		int i;
930 
931 		if (j == 0) {
932 			debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%zd\n",
933 				cursect, mydata->clust_size, DIRENTSPERBLOCK);
934 
935 			if (disk_read(cursect,
936 					(mydata->fatsize == 32) ?
937 					(mydata->clust_size) :
938 					PREFETCH_BLOCKS,
939 					do_fat_read_at_block) < 0) {
940 				debug("Error: reading rootdir block\n");
941 				goto exit;
942 			}
943 
944 			dentptr = (dir_entry *) do_fat_read_at_block;
945 		}
946 
947 		for (i = 0; i < DIRENTSPERBLOCK; i++) {
948 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
949 
950 			l_name[0] = '\0';
951 			if (dentptr->name[0] == DELETED_FLAG) {
952 				dentptr++;
953 				continue;
954 			}
955 			if ((dentptr->attr & ATTR_VOLUME)) {
956 #ifdef CONFIG_SUPPORT_VFAT
957 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
958 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
959 					prevcksum =
960 						((dir_slot *)dentptr)->alias_checksum;
961 
962 					get_vfatname(mydata,
963 						     root_cluster,
964 						     do_fat_read_at_block,
965 						     dentptr, l_name);
966 
967 					if (dols == LS_ROOT) {
968 						char dirc;
969 						int doit = 0;
970 						int isdir =
971 							(dentptr->attr & ATTR_DIR);
972 
973 						if (isdir) {
974 							dirs++;
975 							dirc = '/';
976 							doit = 1;
977 						} else {
978 							dirc = ' ';
979 							if (l_name[0] != 0) {
980 								files++;
981 								doit = 1;
982 							}
983 						}
984 						if (doit) {
985 							if (dirc == ' ') {
986 								printf(" %8ld   %s%c\n",
987 									(long)FAT2CPU32(dentptr->size),
988 									l_name,
989 									dirc);
990 							} else {
991 								printf("            %s%c\n",
992 									l_name,
993 									dirc);
994 							}
995 						}
996 						dentptr++;
997 						continue;
998 					}
999 					debug("Rootvfatname: |%s|\n",
1000 					       l_name);
1001 				} else
1002 #endif
1003 				{
1004 					/* Volume label or VFAT entry */
1005 					dentptr++;
1006 					continue;
1007 				}
1008 			} else if (dentptr->name[0] == 0) {
1009 				debug("RootDentname == NULL - %d\n", i);
1010 				if (dols == LS_ROOT) {
1011 					printf("\n%d file(s), %d dir(s)\n\n",
1012 						files, dirs);
1013 					ret = 0;
1014 				}
1015 				goto exit;
1016 			}
1017 #ifdef CONFIG_SUPPORT_VFAT
1018 			else if (dols == LS_ROOT &&
1019 				 mkcksum(dentptr->name) == prevcksum) {
1020 				prevcksum = 0xffff;
1021 				dentptr++;
1022 				continue;
1023 			}
1024 #endif
1025 			get_name(dentptr, s_name);
1026 
1027 			if (dols == LS_ROOT) {
1028 				int isdir = (dentptr->attr & ATTR_DIR);
1029 				char dirc;
1030 				int doit = 0;
1031 
1032 				if (isdir) {
1033 					dirc = '/';
1034 					if (s_name[0] != 0) {
1035 						dirs++;
1036 						doit = 1;
1037 					}
1038 				} else {
1039 					dirc = ' ';
1040 					if (s_name[0] != 0) {
1041 						files++;
1042 						doit = 1;
1043 					}
1044 				}
1045 				if (doit) {
1046 					if (dirc == ' ') {
1047 						printf(" %8ld   %s%c\n",
1048 							(long)FAT2CPU32(dentptr->size),
1049 							s_name, dirc);
1050 					} else {
1051 						printf("            %s%c\n",
1052 							s_name, dirc);
1053 					}
1054 				}
1055 				dentptr++;
1056 				continue;
1057 			}
1058 
1059 			if (strcmp(fnamecopy, s_name)
1060 			    && strcmp(fnamecopy, l_name)) {
1061 				debug("RootMismatch: |%s|%s|\n", s_name,
1062 				       l_name);
1063 				dentptr++;
1064 				continue;
1065 			}
1066 
1067 			if (isdir && !(dentptr->attr & ATTR_DIR))
1068 				goto exit;
1069 
1070 			debug("RootName: %s", s_name);
1071 			debug(", start: 0x%x", START(dentptr));
1072 			debug(", size:  0x%x %s\n",
1073 			       FAT2CPU32(dentptr->size),
1074 			       isdir ? "(DIR)" : "");
1075 
1076 			goto rootdir_done;	/* We got a match */
1077 		}
1078 		debug("END LOOP: j=%d   clust_size=%d\n", j,
1079 		       mydata->clust_size);
1080 
1081 		/*
1082 		 * On FAT32 we must fetch the FAT entries for the next
1083 		 * root directory clusters when a cluster has been
1084 		 * completely processed.
1085 		 */
1086 		++j;
1087 		int rootdir_end = 0;
1088 		if (mydata->fatsize == 32) {
1089 			if (j == mydata->clust_size) {
1090 				int nxtsect = 0;
1091 				int nxt_clust = 0;
1092 
1093 				nxt_clust = get_fatent(mydata, root_cluster);
1094 				rootdir_end = CHECK_CLUST(nxt_clust, 32);
1095 
1096 				nxtsect = mydata->data_begin +
1097 					(nxt_clust * mydata->clust_size);
1098 
1099 				root_cluster = nxt_clust;
1100 
1101 				cursect = nxtsect;
1102 				j = 0;
1103 			}
1104 		} else {
1105 			if (j == PREFETCH_BLOCKS)
1106 				j = 0;
1107 
1108 			rootdir_end = (++cursect - mydata->rootdir_sect >=
1109 				       rootdir_size);
1110 		}
1111 
1112 		/* If end of rootdir reached */
1113 		if (rootdir_end) {
1114 			if (dols == LS_ROOT) {
1115 				printf("\n%d file(s), %d dir(s)\n\n",
1116 				       files, dirs);
1117 				ret = 0;
1118 			}
1119 			goto exit;
1120 		}
1121 	}
1122 rootdir_done:
1123 
1124 	firsttime = 1;
1125 
1126 	while (isdir) {
1127 		int startsect = mydata->data_begin
1128 			+ START(dentptr) * mydata->clust_size;
1129 		dir_entry dent;
1130 		char *nextname = NULL;
1131 
1132 		dent = *dentptr;
1133 		dentptr = &dent;
1134 
1135 		idx = dirdelim(subname);
1136 
1137 		if (idx >= 0) {
1138 			subname[idx] = '\0';
1139 			nextname = subname + idx + 1;
1140 			/* Handle multiple delimiters */
1141 			while (ISDIRDELIM(*nextname))
1142 				nextname++;
1143 			if (dols && *nextname == '\0')
1144 				firsttime = 0;
1145 		} else {
1146 			if (dols && firsttime) {
1147 				firsttime = 0;
1148 			} else {
1149 				isdir = 0;
1150 			}
1151 		}
1152 
1153 		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1154 				     isdir ? 0 : dols) == NULL) {
1155 			if (dols && !isdir)
1156 				ret = 0;
1157 			goto exit;
1158 		}
1159 
1160 		if (isdir && !(dentptr->attr & ATTR_DIR))
1161 			goto exit;
1162 
1163 		if (idx >= 0)
1164 			subname = nextname;
1165 	}
1166 
1167 	ret = get_contents(mydata, dentptr, pos, buffer, maxsize);
1168 	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
1169 
1170 exit:
1171 	free(mydata->fatbuf);
1172 	return ret;
1173 }
1174 
1175 long
1176 do_fat_read(const char *filename, void *buffer, unsigned long maxsize, int dols)
1177 {
1178 	return do_fat_read_at(filename, 0, buffer, maxsize, dols);
1179 }
1180 
1181 int file_fat_detectfs(void)
1182 {
1183 	boot_sector bs;
1184 	volume_info volinfo;
1185 	int fatsize;
1186 	char vol_label[12];
1187 
1188 	if (cur_dev == NULL) {
1189 		printf("No current device\n");
1190 		return 1;
1191 	}
1192 
1193 #if defined(CONFIG_CMD_IDE) || \
1194     defined(CONFIG_CMD_SATA) || \
1195     defined(CONFIG_CMD_SCSI) || \
1196     defined(CONFIG_CMD_USB) || \
1197     defined(CONFIG_MMC)
1198 	printf("Interface:  ");
1199 	switch (cur_dev->if_type) {
1200 	case IF_TYPE_IDE:
1201 		printf("IDE");
1202 		break;
1203 	case IF_TYPE_SATA:
1204 		printf("SATA");
1205 		break;
1206 	case IF_TYPE_SCSI:
1207 		printf("SCSI");
1208 		break;
1209 	case IF_TYPE_ATAPI:
1210 		printf("ATAPI");
1211 		break;
1212 	case IF_TYPE_USB:
1213 		printf("USB");
1214 		break;
1215 	case IF_TYPE_DOC:
1216 		printf("DOC");
1217 		break;
1218 	case IF_TYPE_MMC:
1219 		printf("MMC");
1220 		break;
1221 	default:
1222 		printf("Unknown");
1223 	}
1224 
1225 	printf("\n  Device %d: ", cur_dev->dev);
1226 	dev_print(cur_dev);
1227 #endif
1228 
1229 	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1230 		printf("\nNo valid FAT fs found\n");
1231 		return 1;
1232 	}
1233 
1234 	memcpy(vol_label, volinfo.volume_label, 11);
1235 	vol_label[11] = '\0';
1236 	volinfo.fs_type[5] = '\0';
1237 
1238 	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part_nr,
1239 		volinfo.fs_type, vol_label);
1240 
1241 	return 0;
1242 }
1243 
1244 int file_fat_ls(const char *dir)
1245 {
1246 	return do_fat_read(dir, NULL, 0, LS_YES);
1247 }
1248 
1249 long file_fat_read_at(const char *filename, unsigned long pos, void *buffer,
1250 		      unsigned long maxsize)
1251 {
1252 	printf("reading %s\n", filename);
1253 	return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO);
1254 }
1255 
1256 long file_fat_read(const char *filename, void *buffer, unsigned long maxsize)
1257 {
1258 	return file_fat_read_at(filename, 0, buffer, maxsize);
1259 }
1260