xref: /openbmc/u-boot/fs/fat/fat.c (revision 18652864)
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 #include <linux/ctype.h>
37 
38 #ifdef CONFIG_SUPPORT_VFAT
39 static const int vfat_enabled = 1;
40 #else
41 static const int vfat_enabled = 0;
42 #endif
43 
44 /*
45  * Convert a string to lowercase.
46  */
47 static void downcase(char *str)
48 {
49 	while (*str != '\0') {
50 		*str = tolower(*str);
51 		str++;
52 	}
53 }
54 
55 static block_dev_desc_t *cur_dev;
56 static disk_partition_t cur_part_info;
57 
58 #define DOS_BOOT_MAGIC_OFFSET	0x1fe
59 #define DOS_FS_TYPE_OFFSET	0x36
60 #define DOS_FS32_TYPE_OFFSET	0x52
61 
62 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
63 {
64 	if (!cur_dev || !cur_dev->block_read)
65 		return -1;
66 
67 	return cur_dev->block_read(cur_dev->dev,
68 			cur_part_info.start + block, nr_blocks, buf);
69 }
70 
71 int fat_set_blk_dev(block_dev_desc_t *dev_desc, disk_partition_t *info)
72 {
73 	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
74 
75 	cur_dev = dev_desc;
76 	cur_part_info = *info;
77 
78 	/* Make sure it has a valid FAT header */
79 	if (disk_read(0, 1, buffer) != 1) {
80 		cur_dev = NULL;
81 		return -1;
82 	}
83 
84 	/* Check if it's actually a DOS volume */
85 	if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
86 		cur_dev = NULL;
87 		return -1;
88 	}
89 
90 	/* Check for FAT12/FAT16/FAT32 filesystem */
91 	if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
92 		return 0;
93 	if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
94 		return 0;
95 
96 	cur_dev = NULL;
97 	return -1;
98 }
99 
100 int fat_register_device(block_dev_desc_t *dev_desc, int part_no)
101 {
102 	disk_partition_t info;
103 
104 	/* First close any currently found FAT filesystem */
105 	cur_dev = NULL;
106 
107 	/* Read the partition table, if present */
108 	if (get_partition_info(dev_desc, part_no, &info)) {
109 		if (part_no != 0) {
110 			printf("** Partition %d not valid on device %d **\n",
111 					part_no, dev_desc->dev);
112 			return -1;
113 		}
114 
115 		info.start = 0;
116 		info.size = dev_desc->lba;
117 		info.blksz = dev_desc->blksz;
118 		info.name[0] = 0;
119 		info.type[0] = 0;
120 		info.bootable = 0;
121 #ifdef CONFIG_PARTITION_UUIDS
122 		info.uuid[0] = 0;
123 #endif
124 	}
125 
126 	return fat_set_blk_dev(dev_desc, &info);
127 }
128 
129 /*
130  * Get the first occurence of a directory delimiter ('/' or '\') in a string.
131  * Return index into string if found, -1 otherwise.
132  */
133 static int dirdelim(char *str)
134 {
135 	char *start = str;
136 
137 	while (*str != '\0') {
138 		if (ISDIRDELIM(*str))
139 			return str - start;
140 		str++;
141 	}
142 	return -1;
143 }
144 
145 /*
146  * Extract zero terminated short name from a directory entry.
147  */
148 static void get_name(dir_entry *dirent, char *s_name)
149 {
150 	char *ptr;
151 
152 	memcpy(s_name, dirent->name, 8);
153 	s_name[8] = '\0';
154 	ptr = s_name;
155 	while (*ptr && *ptr != ' ')
156 		ptr++;
157 	if (dirent->ext[0] && dirent->ext[0] != ' ') {
158 		*ptr = '.';
159 		ptr++;
160 		memcpy(ptr, dirent->ext, 3);
161 		ptr[3] = '\0';
162 		while (*ptr && *ptr != ' ')
163 			ptr++;
164 	}
165 	*ptr = '\0';
166 	if (*s_name == DELETED_FLAG)
167 		*s_name = '\0';
168 	else if (*s_name == aRING)
169 		*s_name = DELETED_FLAG;
170 	downcase(s_name);
171 }
172 
173 /*
174  * Get the entry at index 'entry' in a FAT (12/16/32) table.
175  * On failure 0x00 is returned.
176  */
177 static __u32 get_fatent(fsdata *mydata, __u32 entry)
178 {
179 	__u32 bufnum;
180 	__u32 off16, offset;
181 	__u32 ret = 0x00;
182 	__u16 val1, val2;
183 
184 	switch (mydata->fatsize) {
185 	case 32:
186 		bufnum = entry / FAT32BUFSIZE;
187 		offset = entry - bufnum * FAT32BUFSIZE;
188 		break;
189 	case 16:
190 		bufnum = entry / FAT16BUFSIZE;
191 		offset = entry - bufnum * FAT16BUFSIZE;
192 		break;
193 	case 12:
194 		bufnum = entry / FAT12BUFSIZE;
195 		offset = entry - bufnum * FAT12BUFSIZE;
196 		break;
197 
198 	default:
199 		/* Unsupported FAT size */
200 		return ret;
201 	}
202 
203 	debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
204 	       mydata->fatsize, entry, entry, offset, offset);
205 
206 	/* Read a new block of FAT entries into the cache. */
207 	if (bufnum != mydata->fatbufnum) {
208 		__u32 getsize = FATBUFBLOCKS;
209 		__u8 *bufptr = mydata->fatbuf;
210 		__u32 fatlength = mydata->fatlength;
211 		__u32 startblock = bufnum * FATBUFBLOCKS;
212 
213 		if (startblock + getsize > fatlength)
214 			getsize = fatlength - startblock;
215 
216 		startblock += mydata->fat_sect;	/* Offset from start of disk */
217 
218 		if (disk_read(startblock, getsize, bufptr) < 0) {
219 			debug("Error reading FAT blocks\n");
220 			return ret;
221 		}
222 		mydata->fatbufnum = bufnum;
223 	}
224 
225 	/* Get the actual entry from the table */
226 	switch (mydata->fatsize) {
227 	case 32:
228 		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
229 		break;
230 	case 16:
231 		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
232 		break;
233 	case 12:
234 		off16 = (offset * 3) / 4;
235 
236 		switch (offset & 0x3) {
237 		case 0:
238 			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
239 			ret &= 0xfff;
240 			break;
241 		case 1:
242 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
243 			val1 &= 0xf000;
244 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
245 			val2 &= 0x00ff;
246 			ret = (val2 << 4) | (val1 >> 12);
247 			break;
248 		case 2:
249 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
250 			val1 &= 0xff00;
251 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
252 			val2 &= 0x000f;
253 			ret = (val2 << 8) | (val1 >> 8);
254 			break;
255 		case 3:
256 			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
257 			ret = (ret & 0xfff0) >> 4;
258 			break;
259 		default:
260 			break;
261 		}
262 		break;
263 	}
264 	debug("FAT%d: ret: %08x, offset: %04x\n",
265 	       mydata->fatsize, ret, offset);
266 
267 	return ret;
268 }
269 
270 /*
271  * Read at most 'size' bytes from the specified cluster into 'buffer'.
272  * Return 0 on success, -1 otherwise.
273  */
274 static int
275 get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
276 {
277 	__u32 idx = 0;
278 	__u32 startsect;
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 	if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
291 		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
292 
293 		printf("FAT: Misaligned buffer address (%p)\n", buffer);
294 
295 		while (size >= mydata->sect_size) {
296 			ret = disk_read(startsect++, 1, tmpbuf);
297 			if (ret != 1) {
298 				debug("Error reading data (got %d)\n", ret);
299 				return -1;
300 			}
301 
302 			memcpy(buffer, tmpbuf, mydata->sect_size);
303 			buffer += mydata->sect_size;
304 			size -= mydata->sect_size;
305 		}
306 	} else {
307 		idx = size / mydata->sect_size;
308 		ret = disk_read(startsect, idx, buffer);
309 		if (ret != idx) {
310 			debug("Error reading data (got %d)\n", ret);
311 			return -1;
312 		}
313 		startsect += idx;
314 		idx *= mydata->sect_size;
315 		buffer += idx;
316 		size -= idx;
317 	}
318 	if (size) {
319 		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
320 
321 		ret = disk_read(startsect, 1, tmpbuf);
322 		if (ret != 1) {
323 			debug("Error reading data (got %d)\n", ret);
324 			return -1;
325 		}
326 
327 		memcpy(buffer, tmpbuf, size);
328 	}
329 
330 	return 0;
331 }
332 
333 /*
334  * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
335  * into 'buffer'.
336  * Return the number of bytes read or -1 on fatal errors.
337  */
338 __u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
339 	__aligned(ARCH_DMA_MINALIGN);
340 
341 static long
342 get_contents(fsdata *mydata, dir_entry *dentptr, unsigned long pos,
343 	     __u8 *buffer, unsigned long maxsize)
344 {
345 	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
346 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
347 	__u32 curclust = START(dentptr);
348 	__u32 endclust, newclust;
349 	unsigned long actsize;
350 
351 	debug("Filesize: %ld bytes\n", filesize);
352 
353 	if (pos >= filesize) {
354 		debug("Read position past EOF: %lu\n", pos);
355 		return gotsize;
356 	}
357 
358 	if (maxsize > 0 && filesize > pos + maxsize)
359 		filesize = pos + maxsize;
360 
361 	debug("%ld bytes\n", filesize);
362 
363 	actsize = bytesperclust;
364 
365 	/* go to cluster at pos */
366 	while (actsize <= pos) {
367 		curclust = get_fatent(mydata, curclust);
368 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
369 			debug("curclust: 0x%x\n", curclust);
370 			debug("Invalid FAT entry\n");
371 			return gotsize;
372 		}
373 		actsize += bytesperclust;
374 	}
375 
376 	/* actsize > pos */
377 	actsize -= bytesperclust;
378 	filesize -= actsize;
379 	pos -= actsize;
380 
381 	/* align to beginning of next cluster if any */
382 	if (pos) {
383 		actsize = min(filesize, bytesperclust);
384 		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
385 				(int)actsize) != 0) {
386 			printf("Error reading cluster\n");
387 			return -1;
388 		}
389 		filesize -= actsize;
390 		actsize -= pos;
391 		memcpy(buffer, get_contents_vfatname_block + pos, actsize);
392 		gotsize += actsize;
393 		if (!filesize)
394 			return gotsize;
395 		buffer += actsize;
396 
397 		curclust = get_fatent(mydata, curclust);
398 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
399 			debug("curclust: 0x%x\n", curclust);
400 			debug("Invalid FAT entry\n");
401 			return gotsize;
402 		}
403 	}
404 
405 	actsize = bytesperclust;
406 	endclust = curclust;
407 
408 	do {
409 		/* search for consecutive clusters */
410 		while (actsize < filesize) {
411 			newclust = get_fatent(mydata, endclust);
412 			if ((newclust - 1) != endclust)
413 				goto getit;
414 			if (CHECK_CLUST(newclust, mydata->fatsize)) {
415 				debug("curclust: 0x%x\n", newclust);
416 				debug("Invalid FAT entry\n");
417 				return gotsize;
418 			}
419 			endclust = newclust;
420 			actsize += bytesperclust;
421 		}
422 
423 		/* get remaining bytes */
424 		actsize = filesize;
425 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
426 			printf("Error reading cluster\n");
427 			return -1;
428 		}
429 		gotsize += actsize;
430 		return gotsize;
431 getit:
432 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
433 			printf("Error reading cluster\n");
434 			return -1;
435 		}
436 		gotsize += (int)actsize;
437 		filesize -= actsize;
438 		buffer += actsize;
439 
440 		curclust = get_fatent(mydata, endclust);
441 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
442 			debug("curclust: 0x%x\n", curclust);
443 			printf("Invalid FAT entry\n");
444 			return gotsize;
445 		}
446 		actsize = bytesperclust;
447 		endclust = curclust;
448 	} while (1);
449 }
450 
451 /*
452  * Extract the file name information from 'slotptr' into 'l_name',
453  * starting at l_name[*idx].
454  * Return 1 if terminator (zero byte) is found, 0 otherwise.
455  */
456 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
457 {
458 	int j;
459 
460 	for (j = 0; j <= 8; j += 2) {
461 		l_name[*idx] = slotptr->name0_4[j];
462 		if (l_name[*idx] == 0x00)
463 			return 1;
464 		(*idx)++;
465 	}
466 	for (j = 0; j <= 10; j += 2) {
467 		l_name[*idx] = slotptr->name5_10[j];
468 		if (l_name[*idx] == 0x00)
469 			return 1;
470 		(*idx)++;
471 	}
472 	for (j = 0; j <= 2; j += 2) {
473 		l_name[*idx] = slotptr->name11_12[j];
474 		if (l_name[*idx] == 0x00)
475 			return 1;
476 		(*idx)++;
477 	}
478 
479 	return 0;
480 }
481 
482 /*
483  * Extract the full long filename starting at 'retdent' (which is really
484  * a slot) into 'l_name'. If successful also copy the real directory entry
485  * into 'retdent'
486  * Return 0 on success, -1 otherwise.
487  */
488 static int
489 get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
490 	     dir_entry *retdent, char *l_name)
491 {
492 	dir_entry *realdent;
493 	dir_slot *slotptr = (dir_slot *)retdent;
494 	__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
495 							PREFETCH_BLOCKS :
496 							mydata->clust_size);
497 	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
498 	int idx = 0;
499 
500 	if (counter > VFAT_MAXSEQ) {
501 		debug("Error: VFAT name is too long\n");
502 		return -1;
503 	}
504 
505 	while ((__u8 *)slotptr < buflimit) {
506 		if (counter == 0)
507 			break;
508 		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
509 			return -1;
510 		slotptr++;
511 		counter--;
512 	}
513 
514 	if ((__u8 *)slotptr >= buflimit) {
515 		dir_slot *slotptr2;
516 
517 		if (curclust == 0)
518 			return -1;
519 		curclust = get_fatent(mydata, curclust);
520 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
521 			debug("curclust: 0x%x\n", curclust);
522 			printf("Invalid FAT entry\n");
523 			return -1;
524 		}
525 
526 		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
527 				mydata->clust_size * mydata->sect_size) != 0) {
528 			debug("Error: reading directory block\n");
529 			return -1;
530 		}
531 
532 		slotptr2 = (dir_slot *)get_contents_vfatname_block;
533 		while (counter > 0) {
534 			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
535 			    & 0xff) != counter)
536 				return -1;
537 			slotptr2++;
538 			counter--;
539 		}
540 
541 		/* Save the real directory entry */
542 		realdent = (dir_entry *)slotptr2;
543 		while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
544 			slotptr2--;
545 			slot2str(slotptr2, l_name, &idx);
546 		}
547 	} else {
548 		/* Save the real directory entry */
549 		realdent = (dir_entry *)slotptr;
550 	}
551 
552 	do {
553 		slotptr--;
554 		if (slot2str(slotptr, l_name, &idx))
555 			break;
556 	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
557 
558 	l_name[idx] = '\0';
559 	if (*l_name == DELETED_FLAG)
560 		*l_name = '\0';
561 	else if (*l_name == aRING)
562 		*l_name = DELETED_FLAG;
563 	downcase(l_name);
564 
565 	/* Return the real directory entry */
566 	memcpy(retdent, realdent, sizeof(dir_entry));
567 
568 	return 0;
569 }
570 
571 /* Calculate short name checksum */
572 static __u8 mkcksum(const char name[8], const char ext[3])
573 {
574 	int i;
575 
576 	__u8 ret = 0;
577 
578 	for (i = 0; i < 8; i++)
579 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
580 	for (i = 0; i < 3; i++)
581 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
582 
583 	return ret;
584 }
585 
586 /*
587  * Get the directory entry associated with 'filename' from the directory
588  * starting at 'startsect'
589  */
590 __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
591 	__aligned(ARCH_DMA_MINALIGN);
592 
593 static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
594 				  char *filename, dir_entry *retdent,
595 				  int dols)
596 {
597 	__u16 prevcksum = 0xffff;
598 	__u32 curclust = START(retdent);
599 	int files = 0, dirs = 0;
600 
601 	debug("get_dentfromdir: %s\n", filename);
602 
603 	while (1) {
604 		dir_entry *dentptr;
605 
606 		int i;
607 
608 		if (get_cluster(mydata, curclust, get_dentfromdir_block,
609 				mydata->clust_size * mydata->sect_size) != 0) {
610 			debug("Error: reading directory block\n");
611 			return NULL;
612 		}
613 
614 		dentptr = (dir_entry *)get_dentfromdir_block;
615 
616 		for (i = 0; i < DIRENTSPERCLUST; i++) {
617 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
618 
619 			l_name[0] = '\0';
620 			if (dentptr->name[0] == DELETED_FLAG) {
621 				dentptr++;
622 				continue;
623 			}
624 			if ((dentptr->attr & ATTR_VOLUME)) {
625 				if (vfat_enabled &&
626 				    (dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
627 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
628 					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
629 					get_vfatname(mydata, curclust,
630 						     get_dentfromdir_block,
631 						     dentptr, l_name);
632 					if (dols) {
633 						int isdir;
634 						char dirc;
635 						int doit = 0;
636 
637 						isdir = (dentptr->attr & ATTR_DIR);
638 
639 						if (isdir) {
640 							dirs++;
641 							dirc = '/';
642 							doit = 1;
643 						} else {
644 							dirc = ' ';
645 							if (l_name[0] != 0) {
646 								files++;
647 								doit = 1;
648 							}
649 						}
650 						if (doit) {
651 							if (dirc == ' ') {
652 								printf(" %8ld   %s%c\n",
653 									(long)FAT2CPU32(dentptr->size),
654 									l_name,
655 									dirc);
656 							} else {
657 								printf("            %s%c\n",
658 									l_name,
659 									dirc);
660 							}
661 						}
662 						dentptr++;
663 						continue;
664 					}
665 					debug("vfatname: |%s|\n", l_name);
666 				} else {
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 			if (vfat_enabled) {
681 				__u8 csum = mkcksum(dentptr->name, dentptr->ext);
682 				if (dols && csum == prevcksum) {
683 					prevcksum = 0xffff;
684 					dentptr++;
685 					continue;
686 				}
687 			}
688 
689 			get_name(dentptr, s_name);
690 			if (dols) {
691 				int isdir = (dentptr->attr & ATTR_DIR);
692 				char dirc;
693 				int doit = 0;
694 
695 				if (isdir) {
696 					dirs++;
697 					dirc = '/';
698 					doit = 1;
699 				} else {
700 					dirc = ' ';
701 					if (s_name[0] != 0) {
702 						files++;
703 						doit = 1;
704 					}
705 				}
706 
707 				if (doit) {
708 					if (dirc == ' ') {
709 						printf(" %8ld   %s%c\n",
710 							(long)FAT2CPU32(dentptr->size),
711 							s_name, dirc);
712 					} else {
713 						printf("            %s%c\n",
714 							s_name, dirc);
715 					}
716 				}
717 
718 				dentptr++;
719 				continue;
720 			}
721 
722 			if (strcmp(filename, s_name)
723 			    && strcmp(filename, l_name)) {
724 				debug("Mismatch: |%s|%s|\n", s_name, l_name);
725 				dentptr++;
726 				continue;
727 			}
728 
729 			memcpy(retdent, dentptr, sizeof(dir_entry));
730 
731 			debug("DentName: %s", s_name);
732 			debug(", start: 0x%x", START(dentptr));
733 			debug(", size:  0x%x %s\n",
734 			      FAT2CPU32(dentptr->size),
735 			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
736 
737 			return retdent;
738 		}
739 
740 		curclust = get_fatent(mydata, curclust);
741 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
742 			debug("curclust: 0x%x\n", curclust);
743 			printf("Invalid FAT entry\n");
744 			return NULL;
745 		}
746 	}
747 
748 	return NULL;
749 }
750 
751 /*
752  * Read boot sector and volume info from a FAT filesystem
753  */
754 static int
755 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
756 {
757 	__u8 *block;
758 	volume_info *vistart;
759 	int ret = 0;
760 
761 	if (cur_dev == NULL) {
762 		debug("Error: no device selected\n");
763 		return -1;
764 	}
765 
766 	block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
767 	if (block == NULL) {
768 		debug("Error: allocating block\n");
769 		return -1;
770 	}
771 
772 	if (disk_read(0, 1, block) < 0) {
773 		debug("Error: reading block\n");
774 		goto fail;
775 	}
776 
777 	memcpy(bs, block, sizeof(boot_sector));
778 	bs->reserved = FAT2CPU16(bs->reserved);
779 	bs->fat_length = FAT2CPU16(bs->fat_length);
780 	bs->secs_track = FAT2CPU16(bs->secs_track);
781 	bs->heads = FAT2CPU16(bs->heads);
782 	bs->total_sect = FAT2CPU32(bs->total_sect);
783 
784 	/* FAT32 entries */
785 	if (bs->fat_length == 0) {
786 		/* Assume FAT32 */
787 		bs->fat32_length = FAT2CPU32(bs->fat32_length);
788 		bs->flags = FAT2CPU16(bs->flags);
789 		bs->root_cluster = FAT2CPU32(bs->root_cluster);
790 		bs->info_sector = FAT2CPU16(bs->info_sector);
791 		bs->backup_boot = FAT2CPU16(bs->backup_boot);
792 		vistart = (volume_info *)(block + sizeof(boot_sector));
793 		*fatsize = 32;
794 	} else {
795 		vistart = (volume_info *)&(bs->fat32_length);
796 		*fatsize = 0;
797 	}
798 	memcpy(volinfo, vistart, sizeof(volume_info));
799 
800 	if (*fatsize == 32) {
801 		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
802 			goto exit;
803 	} else {
804 		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
805 			*fatsize = 12;
806 			goto exit;
807 		}
808 		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
809 			*fatsize = 16;
810 			goto exit;
811 		}
812 	}
813 
814 	debug("Error: broken fs_type sign\n");
815 fail:
816 	ret = -1;
817 exit:
818 	free(block);
819 	return ret;
820 }
821 
822 __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
823 	__aligned(ARCH_DMA_MINALIGN);
824 
825 long
826 do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
827 	       unsigned long maxsize, int dols)
828 {
829 	char fnamecopy[2048];
830 	boot_sector bs;
831 	volume_info volinfo;
832 	fsdata datablock;
833 	fsdata *mydata = &datablock;
834 	dir_entry *dentptr = NULL;
835 	__u16 prevcksum = 0xffff;
836 	char *subname = "";
837 	__u32 cursect;
838 	int idx, isdir = 0;
839 	int files = 0, dirs = 0;
840 	long ret = -1;
841 	int firsttime;
842 	__u32 root_cluster = 0;
843 	int rootdir_size = 0;
844 	int j;
845 
846 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
847 		debug("Error: reading boot sector\n");
848 		return -1;
849 	}
850 
851 	if (mydata->fatsize == 32) {
852 		root_cluster = bs.root_cluster;
853 		mydata->fatlength = bs.fat32_length;
854 	} else {
855 		mydata->fatlength = bs.fat_length;
856 	}
857 
858 	mydata->fat_sect = bs.reserved;
859 
860 	cursect = mydata->rootdir_sect
861 		= mydata->fat_sect + mydata->fatlength * bs.fats;
862 
863 	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
864 	mydata->clust_size = bs.cluster_size;
865 	if (mydata->sect_size != cur_part_info.blksz) {
866 		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
867 				mydata->sect_size, cur_part_info.blksz);
868 		return -1;
869 	}
870 
871 	if (mydata->fatsize == 32) {
872 		mydata->data_begin = mydata->rootdir_sect -
873 					(mydata->clust_size * 2);
874 	} else {
875 		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
876 				 bs.dir_entries[0]) *
877 				 sizeof(dir_entry)) /
878 				 mydata->sect_size;
879 		mydata->data_begin = mydata->rootdir_sect +
880 					rootdir_size -
881 					(mydata->clust_size * 2);
882 	}
883 
884 	mydata->fatbufnum = -1;
885 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
886 	if (mydata->fatbuf == NULL) {
887 		debug("Error: allocating memory\n");
888 		return -1;
889 	}
890 
891 	if (vfat_enabled)
892 		debug("VFAT Support enabled\n");
893 
894 	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
895 	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
896 	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
897 	       "Data begins at: %d\n",
898 	       root_cluster,
899 	       mydata->rootdir_sect,
900 	       mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
901 	debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
902 	      mydata->clust_size);
903 
904 	/* "cwd" is always the root... */
905 	while (ISDIRDELIM(*filename))
906 		filename++;
907 
908 	/* Make a copy of the filename and convert it to lowercase */
909 	strcpy(fnamecopy, filename);
910 	downcase(fnamecopy);
911 
912 	if (*fnamecopy == '\0') {
913 		if (!dols)
914 			goto exit;
915 
916 		dols = LS_ROOT;
917 	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
918 		isdir = 1;
919 		fnamecopy[idx] = '\0';
920 		subname = fnamecopy + idx + 1;
921 
922 		/* Handle multiple delimiters */
923 		while (ISDIRDELIM(*subname))
924 			subname++;
925 	} else if (dols) {
926 		isdir = 1;
927 	}
928 
929 	j = 0;
930 	while (1) {
931 		int i;
932 
933 		if (j == 0) {
934 			debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%zd\n",
935 				cursect, mydata->clust_size, DIRENTSPERBLOCK);
936 
937 			if (disk_read(cursect,
938 					(mydata->fatsize == 32) ?
939 					(mydata->clust_size) :
940 					PREFETCH_BLOCKS,
941 					do_fat_read_at_block) < 0) {
942 				debug("Error: reading rootdir block\n");
943 				goto exit;
944 			}
945 
946 			dentptr = (dir_entry *) do_fat_read_at_block;
947 		}
948 
949 		for (i = 0; i < DIRENTSPERBLOCK; i++) {
950 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
951 			__u8 csum;
952 
953 			l_name[0] = '\0';
954 			if (dentptr->name[0] == DELETED_FLAG) {
955 				dentptr++;
956 				continue;
957 			}
958 
959 			if (vfat_enabled)
960 				csum = mkcksum(dentptr->name, dentptr->ext);
961 
962 			if (dentptr->attr & ATTR_VOLUME) {
963 				if (vfat_enabled &&
964 				    (dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
965 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
966 					prevcksum =
967 						((dir_slot *)dentptr)->alias_checksum;
968 
969 					get_vfatname(mydata,
970 						     root_cluster,
971 						     do_fat_read_at_block,
972 						     dentptr, l_name);
973 
974 					if (dols == LS_ROOT) {
975 						char dirc;
976 						int doit = 0;
977 						int isdir =
978 							(dentptr->attr & ATTR_DIR);
979 
980 						if (isdir) {
981 							dirs++;
982 							dirc = '/';
983 							doit = 1;
984 						} else {
985 							dirc = ' ';
986 							if (l_name[0] != 0) {
987 								files++;
988 								doit = 1;
989 							}
990 						}
991 						if (doit) {
992 							if (dirc == ' ') {
993 								printf(" %8ld   %s%c\n",
994 									(long)FAT2CPU32(dentptr->size),
995 									l_name,
996 									dirc);
997 							} else {
998 								printf("            %s%c\n",
999 									l_name,
1000 									dirc);
1001 							}
1002 						}
1003 						dentptr++;
1004 						continue;
1005 					}
1006 					debug("Rootvfatname: |%s|\n",
1007 					       l_name);
1008 				} else {
1009 					/* Volume label or VFAT entry */
1010 					dentptr++;
1011 					continue;
1012 				}
1013 			} else if (dentptr->name[0] == 0) {
1014 				debug("RootDentname == NULL - %d\n", i);
1015 				if (dols == LS_ROOT) {
1016 					printf("\n%d file(s), %d dir(s)\n\n",
1017 						files, dirs);
1018 					ret = 0;
1019 				}
1020 				goto exit;
1021 			}
1022 			else if (vfat_enabled &&
1023 				 dols == LS_ROOT && csum == prevcksum) {
1024 				prevcksum = 0xffff;
1025 				dentptr++;
1026 				continue;
1027 			}
1028 
1029 			get_name(dentptr, s_name);
1030 
1031 			if (dols == LS_ROOT) {
1032 				int isdir = (dentptr->attr & ATTR_DIR);
1033 				char dirc;
1034 				int doit = 0;
1035 
1036 				if (isdir) {
1037 					dirc = '/';
1038 					if (s_name[0] != 0) {
1039 						dirs++;
1040 						doit = 1;
1041 					}
1042 				} else {
1043 					dirc = ' ';
1044 					if (s_name[0] != 0) {
1045 						files++;
1046 						doit = 1;
1047 					}
1048 				}
1049 				if (doit) {
1050 					if (dirc == ' ') {
1051 						printf(" %8ld   %s%c\n",
1052 							(long)FAT2CPU32(dentptr->size),
1053 							s_name, dirc);
1054 					} else {
1055 						printf("            %s%c\n",
1056 							s_name, dirc);
1057 					}
1058 				}
1059 				dentptr++;
1060 				continue;
1061 			}
1062 
1063 			if (strcmp(fnamecopy, s_name)
1064 			    && strcmp(fnamecopy, l_name)) {
1065 				debug("RootMismatch: |%s|%s|\n", s_name,
1066 				       l_name);
1067 				dentptr++;
1068 				continue;
1069 			}
1070 
1071 			if (isdir && !(dentptr->attr & ATTR_DIR))
1072 				goto exit;
1073 
1074 			debug("RootName: %s", s_name);
1075 			debug(", start: 0x%x", START(dentptr));
1076 			debug(", size:  0x%x %s\n",
1077 			       FAT2CPU32(dentptr->size),
1078 			       isdir ? "(DIR)" : "");
1079 
1080 			goto rootdir_done;	/* We got a match */
1081 		}
1082 		debug("END LOOP: j=%d   clust_size=%d\n", j,
1083 		       mydata->clust_size);
1084 
1085 		/*
1086 		 * On FAT32 we must fetch the FAT entries for the next
1087 		 * root directory clusters when a cluster has been
1088 		 * completely processed.
1089 		 */
1090 		++j;
1091 		int rootdir_end = 0;
1092 		if (mydata->fatsize == 32) {
1093 			if (j == mydata->clust_size) {
1094 				int nxtsect = 0;
1095 				int nxt_clust = 0;
1096 
1097 				nxt_clust = get_fatent(mydata, root_cluster);
1098 				rootdir_end = CHECK_CLUST(nxt_clust, 32);
1099 
1100 				nxtsect = mydata->data_begin +
1101 					(nxt_clust * mydata->clust_size);
1102 
1103 				root_cluster = nxt_clust;
1104 
1105 				cursect = nxtsect;
1106 				j = 0;
1107 			}
1108 		} else {
1109 			if (j == PREFETCH_BLOCKS)
1110 				j = 0;
1111 
1112 			rootdir_end = (++cursect - mydata->rootdir_sect >=
1113 				       rootdir_size);
1114 		}
1115 
1116 		/* If end of rootdir reached */
1117 		if (rootdir_end) {
1118 			if (dols == LS_ROOT) {
1119 				printf("\n%d file(s), %d dir(s)\n\n",
1120 				       files, dirs);
1121 				ret = 0;
1122 			}
1123 			goto exit;
1124 		}
1125 	}
1126 rootdir_done:
1127 
1128 	firsttime = 1;
1129 
1130 	while (isdir) {
1131 		int startsect = mydata->data_begin
1132 			+ START(dentptr) * mydata->clust_size;
1133 		dir_entry dent;
1134 		char *nextname = NULL;
1135 
1136 		dent = *dentptr;
1137 		dentptr = &dent;
1138 
1139 		idx = dirdelim(subname);
1140 
1141 		if (idx >= 0) {
1142 			subname[idx] = '\0';
1143 			nextname = subname + idx + 1;
1144 			/* Handle multiple delimiters */
1145 			while (ISDIRDELIM(*nextname))
1146 				nextname++;
1147 			if (dols && *nextname == '\0')
1148 				firsttime = 0;
1149 		} else {
1150 			if (dols && firsttime) {
1151 				firsttime = 0;
1152 			} else {
1153 				isdir = 0;
1154 			}
1155 		}
1156 
1157 		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1158 				     isdir ? 0 : dols) == NULL) {
1159 			if (dols && !isdir)
1160 				ret = 0;
1161 			goto exit;
1162 		}
1163 
1164 		if (isdir && !(dentptr->attr & ATTR_DIR))
1165 			goto exit;
1166 
1167 		if (idx >= 0)
1168 			subname = nextname;
1169 	}
1170 
1171 	ret = get_contents(mydata, dentptr, pos, buffer, maxsize);
1172 	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
1173 
1174 exit:
1175 	free(mydata->fatbuf);
1176 	return ret;
1177 }
1178 
1179 long
1180 do_fat_read(const char *filename, void *buffer, unsigned long maxsize, int dols)
1181 {
1182 	return do_fat_read_at(filename, 0, buffer, maxsize, dols);
1183 }
1184 
1185 int file_fat_detectfs(void)
1186 {
1187 	boot_sector bs;
1188 	volume_info volinfo;
1189 	int fatsize;
1190 	char vol_label[12];
1191 
1192 	if (cur_dev == NULL) {
1193 		printf("No current device\n");
1194 		return 1;
1195 	}
1196 
1197 #if defined(CONFIG_CMD_IDE) || \
1198     defined(CONFIG_CMD_SATA) || \
1199     defined(CONFIG_CMD_SCSI) || \
1200     defined(CONFIG_CMD_USB) || \
1201     defined(CONFIG_MMC)
1202 	printf("Interface:  ");
1203 	switch (cur_dev->if_type) {
1204 	case IF_TYPE_IDE:
1205 		printf("IDE");
1206 		break;
1207 	case IF_TYPE_SATA:
1208 		printf("SATA");
1209 		break;
1210 	case IF_TYPE_SCSI:
1211 		printf("SCSI");
1212 		break;
1213 	case IF_TYPE_ATAPI:
1214 		printf("ATAPI");
1215 		break;
1216 	case IF_TYPE_USB:
1217 		printf("USB");
1218 		break;
1219 	case IF_TYPE_DOC:
1220 		printf("DOC");
1221 		break;
1222 	case IF_TYPE_MMC:
1223 		printf("MMC");
1224 		break;
1225 	default:
1226 		printf("Unknown");
1227 	}
1228 
1229 	printf("\n  Device %d: ", cur_dev->dev);
1230 	dev_print(cur_dev);
1231 #endif
1232 
1233 	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1234 		printf("\nNo valid FAT fs found\n");
1235 		return 1;
1236 	}
1237 
1238 	memcpy(vol_label, volinfo.volume_label, 11);
1239 	vol_label[11] = '\0';
1240 	volinfo.fs_type[5] = '\0';
1241 
1242 	printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1243 
1244 	return 0;
1245 }
1246 
1247 int file_fat_ls(const char *dir)
1248 {
1249 	return do_fat_read(dir, NULL, 0, LS_YES);
1250 }
1251 
1252 long file_fat_read_at(const char *filename, unsigned long pos, void *buffer,
1253 		      unsigned long maxsize)
1254 {
1255 	printf("reading %s\n", filename);
1256 	return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO);
1257 }
1258 
1259 long file_fat_read(const char *filename, void *buffer, unsigned long maxsize)
1260 {
1261 	return file_fat_read_at(filename, 0, buffer, maxsize);
1262 }
1263 
1264 int fat_read_file(const char *filename, void *buf, int offset, int len)
1265 {
1266 	int len_read;
1267 
1268 	len_read = file_fat_read_at(filename, offset, buf, len);
1269 	if (len_read == -1) {
1270 		printf("** Unable to read file %s **\n", filename);
1271 		return -1;
1272 	}
1273 
1274 	return len_read;
1275 }
1276 
1277 void fat_close(void)
1278 {
1279 }
1280