aboutsummaryrefslogtreecommitdiff
path: root/drivers/firmware/dmi_scan.c
blob: 3714e3c03df6ba50ff9c9c1df1128972a481bb4b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
#include <linux/types.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/dmi.h>
#include <linux/efi.h>
#include <linux/bootmem.h>
#include <linux/random.h>
#include <asm/dmi.h>

/*
 * DMI stands for "Desktop Management Interface".  It is part
 * of and an antecedent to, SMBIOS, which stands for System
 * Management BIOS.  See further: http://www.dmtf.org/standards
 */
static char dmi_empty_string[] = "        ";

static u16 __initdata dmi_ver;
/*
 * Catch too early calls to dmi_check_system():
 */
static int dmi_initialized;

static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
{
	const u8 *bp = ((u8 *) dm) + dm->length;

	if (s) {
		s--;
		while (s > 0 && *bp) {
			bp += strlen(bp) + 1;
			s--;
		}

		if (*bp != 0) {
			size_t len = strlen(bp)+1;
			size_t cmp_len = len > 8 ? 8 : len;

			if (!memcmp(bp, dmi_empty_string, cmp_len))
				return dmi_empty_string;
			return bp;
		}
	}

	return "";
}

static char * __init dmi_string(const struct dmi_header *dm, u8 s)
{
	const char *bp = dmi_string_nosave(dm, s);
	char *str;
	size_t len;

	if (bp == dmi_empty_string)
		return dmi_empty_string;

	len = strlen(bp) + 1;
	str = dmi_alloc(len);
	if (str != NULL)
		strcpy(str, bp);
	else
		printk(KERN_ERR "dmi_string: cannot allocate %Zu bytes.\n", len);

	return str;
}

/*
 *	We have to be cautious here. We have seen BIOSes with DMI pointers
 *	pointing to completely the wrong place for example
 */
static void dmi_table(u8 *buf, int len, int num,
		      void (*decode)(const struct dmi_header *, void *),
		      void *private_data)
{
	u8 *data = buf;
	int i = 0;

	/*
	 *	Stop when we see all the items the table claimed to have
	 *	OR we run off the end of the table (also happens)
	 */
	while ((i < num) && (data - buf + sizeof(struct dmi_header)) <= len) {
		const struct dmi_header *dm = (const struct dmi_header *)data;

		/*
		 *  We want to know the total length (formatted area and
		 *  strings) before decoding to make sure we won't run off the
		 *  table in dmi_decode or dmi_string
		 */
		data += dm->length;
		while ((data - buf < len - 1) && (data[0] || data[1]))
			data++;
		if (data - buf < len - 1)
			decode(dm, private_data);
		data += 2;
		i++;
	}
}

static u32 dmi_base;
static u16 dmi_len;
static u16 dmi_num;

static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
		void *))
{
	u8 *buf;

	buf = dmi_ioremap(dmi_base, dmi_len);
	if (buf == NULL)
		return -1;

	dmi_table(buf, dmi_len, dmi_num, decode, NULL);

	add_device_randomness(buf, dmi_len);

	dmi_iounmap(buf, dmi_len);
	return 0;
}

static int __init dmi_checksum(const u8 *buf)
{
	u8 sum = 0;
	int a;

	for (a = 0; a < 15; a++)
		sum += buf[a];

	return sum == 0;
}

static char *dmi_ident[DMI_STRING_MAX];
static LIST_HEAD(dmi_devices);
int dmi_available;

/*
 *	Save a DMI string
 */
static void __init dmi_save_ident(const struct dmi_header *dm, int slot, int string)
{
	const char *d = (const char*) dm;
	char *p;

	if (dmi_ident[slot])
		return;

	p = dmi_string(dm, d[string]);
	if (p == NULL)
		return;

	dmi_ident[slot] = p;
}

static void __init dmi_save_uuid(const struct dmi_header *dm, int slot, int index)
{
	const u8 *d = (u8*) dm + index;
	char *s;
	int is_ff = 1, is_00 = 1, i;

	if (dmi_ident[slot])
		return;

	for (i = 0; i < 16 && (is_ff || is_00); i++) {
		if (d[i] != 0x00)
			is_00 = 0;
		if (d[i] != 0xFF)
			is_ff = 0;
	}

	if (is_ff || is_00)
		return;

	s = dmi_alloc(16*2+4+1);
	if (!s)
		return;

	/*
	 * As of version 2.6 of the SMBIOS specification, the first 3 fields of
	 * the UUID are supposed to be little-endian encoded.  The specification
	 * says that this is the defacto standard.
	 */
	if (dmi_ver >= 0x0206)
		sprintf(s, "%pUL", d);
	else
		sprintf(s, "%pUB", d);

        dmi_ident[slot] = s;
}

static void __init dmi_save_type(const struct dmi_header *dm, int slot, int index)
{
	const u8 *d = (u8*) dm + index;
	char *s;

	if (dmi_ident[slot])
		return;

	s = dmi_alloc(4);
	if (!s)
		return;

	sprintf(s, "%u", *d & 0x7F);
	dmi_ident[slot] = s;
}

static void __init dmi_save_one_device(int type, const char *name)
{
	struct dmi_device *dev;

	/* No duplicate device */
	if (dmi_find_device(type, name, NULL))
		return;

	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
	if (!dev) {
		printk(KERN_ERR "dmi_save_one_device: out of memory.\n");
		return;
	}

	dev->type = type;
	strcpy((char *)(dev + 1), name);
	dev->name = (char *)(dev + 1);
	dev->device_data = NULL;
	list_add(&dev->list, &dmi_devices);
}

static void __init dmi_save_devices(const struct dmi_header *dm)
{
	int i, count = (dm->length - sizeof(struct dmi_header)) / 2;

	for (i = 0; i < count; i++) {
		const char *d = (char *)(dm + 1) + (i * 2);

		/* Skip disabled device */
		if ((*d & 0x80) == 0)
			continue;

		dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
	}
}

static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
{
	int i, count = *(u8 *)(dm + 1);
	struct dmi_device *dev;

	for (i = 1; i <= count; i++) {
		char *devname = dmi_string(dm, i);

		if (devname == dmi_empty_string)
			continue;

		dev = dmi_alloc(sizeof(*dev));
		if (!dev) {
			printk(KERN_ERR
			   "dmi_save_oem_strings_devices: out of memory.\n");
			break;
		}

		dev->type = DMI_DEV_TYPE_OEM_STRING;
		dev->name = devname;
		dev->device_data = NULL;

		list_add(&dev->list, &dmi_devices);
	}
}

static void __init dmi_save_ipmi_device(const struct dmi_header *dm)
{
	struct dmi_device *dev;
	void * data;

	data = dmi_alloc(dm->length);
	if (data == NULL) {
		printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
		return;
	}

	memcpy(data, dm, dm->length);

	dev = dmi_alloc(sizeof(*dev));
	if (!dev) {
		printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
		return;
	}

	dev->type = DMI_DEV_TYPE_IPMI;
	dev->name = "IPMI controller";
	dev->device_data = data;

	list_add_tail(&dev->list, &dmi_devices);
}

static void __init dmi_save_dev_onboard(int instance, int segment, int bus,
					int devfn, const char *name)
{
	struct dmi_dev_onboard *onboard_dev;

	onboard_dev = dmi_alloc(sizeof(*onboard_dev) + strlen(name) + 1);
	if (!onboard_dev) {
		printk(KERN_ERR "dmi_save_dev_onboard: out of memory.\n");
		return;
	}
	onboard_dev->instance = instance;
	onboard_dev->segment = segment;
	onboard_dev->bus = bus;
	onboard_dev->devfn = devfn;

	strcpy((char *)&onboard_dev[1], name);
	onboard_dev->dev.type = DMI_DEV_TYPE_DEV_ONBOARD;
	onboard_dev->dev.name = (char *)&onboard_dev[1];
	onboard_dev->dev.device_data = onboard_dev;

	list_add(&onboard_dev->dev.list, &dmi_devices);
}

static void __init dmi_save_extended_devices(const struct dmi_header *dm)
{
	const u8 *d = (u8*) dm + 5;

	/* Skip disabled device */
	if ((*d & 0x80) == 0)
		return;

	dmi_save_dev_onboard(*(d+1), *(u16 *)(d+2), *(d+4), *(d+5),
			     dmi_string_nosave(dm, *(d-1)));
	dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
}

/*
 *	Process a DMI table entry. Right now all we care about are the BIOS
 *	and machine entries. For 2.5 we should pull the smbus controller info
 *	out of here.
 */
static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
{
	switch(dm->type) {
	case 0:		/* BIOS Information */
		dmi_save_ident(dm, DMI_BIOS_VENDOR, 4);
		dmi_save_ident(dm, DMI_BIOS_VERSION, 5);
		dmi_save_ident(dm, DMI_BIOS_DATE, 8);
		break;
	case 1:		/* System Information */
		dmi_save_ident(dm, DMI_SYS_VENDOR, 4);
		dmi_save_ident(dm, DMI_PRODUCT_NAME, 5);
		dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
		dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
		dmi_save_uuid(dm, DMI_PRODUCT_UUID, 8);
		break;
	case 2:		/* Base Board Information */
		dmi_save_ident(dm, DMI_BOARD_VENDOR, 4);
		dmi_save_ident(dm, DMI_BOARD_NAME, 5);
		dmi_save_ident(dm, DMI_BOARD_VERSION, 6);
		dmi_save_ident(dm, DMI_BOARD_SERIAL, 7);
		dmi_save_ident(dm, DMI_BOARD_ASSET_TAG, 8);
		break;
	case 3:		/* Chassis Information */
		dmi_save_ident(dm, DMI_CHASSIS_VENDOR, 4);
		dmi_save_type(dm, DMI_CHASSIS_TYPE, 5);
		dmi_save_ident(dm, DMI_CHASSIS_VERSION, 6);
		dmi_save_ident(dm, DMI_CHASSIS_SERIAL, 7);
		dmi_save_ident(dm, DMI_CHASSIS_ASSET_TAG, 8);
		break;
	case 10:	/* Onboard Devices Information */
		dmi_save_devices(dm);
		break;
	case 11:	/* OEM Strings */
		dmi_save_oem_strings_devices(dm);
		break;
	case 38:	/* IPMI Device Information */
		dmi_save_ipmi_device(dm);
		break;
	case 41:	/* Onboard Devices Extended Information */
		dmi_save_extended_devices(dm);
	}
}

static void __init print_filtered(const char *info)
{
	const char *p;

	if (!info)
		return;

	for (p = info; *p; p++)
		if (isprint(*p))
			printk(KERN_CONT "%c", *p);
		else
			printk(KERN_CONT "\\x%02x", *p & 0xff);
}

static void __init dmi_dump_ids(void)
{
	const char *board;	/* Board Name is optional */

	printk(KERN_DEBUG "DMI: ");
	print_filtered(dmi_get_system_info(DMI_SYS_VENDOR));
	printk(KERN_CONT " ");
	print_filtered(dmi_get_system_info(DMI_PRODUCT_NAME));
	board = dmi_get_system_info(DMI_BOARD_NAME);
	if (board) {
		printk(KERN_CONT "/");
		print_filtered(board);
	}
	printk(KERN_CONT ", BIOS ");
	print_filtered(dmi_get_system_info(DMI_BIOS_VERSION));
	printk(KERN_CONT " ");
	print_filtered(dmi_get_system_info(DMI_BIOS_DATE));
	printk(KERN_CONT "\n");
}

static int __init dmi_present(const char __iomem *p)
{
	u8 buf[15];

	memcpy_fromio(buf, p, 15);
	if ((memcmp(buf, "_DMI_", 5) == 0) && dmi_checksum(buf)) {
		dmi_num = (buf[13] << 8) | buf[12];
		dmi_len = (buf[7] << 8) | buf[6];
		dmi_base = (buf[11] << 24) | (buf[10] << 16) |
			(buf[9] << 8) | buf[8];

		/*
		 * DMI version 0.0 means that the real version is taken from
		 * the SMBIOS version, which we don't know at this point.
		 */
		dmi_ver = (buf[14] & 0xf0) << 4 | (buf[14] & 0x0f);
		if (buf[14] != 0)
			printk(KERN_INFO "DMI %d.%d present.\n",
			       buf[14] >> 4, buf[14] & 0xF);
		else
			printk(KERN_INFO "DMI present.\n");
		if (dmi_walk_early(dmi_decode) == 0) {
			dmi_dump_ids();
			return 0;
		}
	}
	return 1;
}

void __init dmi_scan_machine(void)
{
	char __iomem *p, *q;
	int rc;

	if (efi_enabled) {
		if (efi.smbios == EFI_INVALID_TABLE_ADDR)
			goto error;

		/* This is called as a core_initcall() because it isn't
		 * needed during early boot.  This also means we can
		 * iounmap the space when we're done with it.
		 */
		p = dmi_ioremap(efi.smbios, 32);
		if (p == NULL)
			goto error;

		rc = dmi_present(p + 0x10); /* offset of _DMI_ string */
		dmi_iounmap(p, 32);
		if (!rc) {
			dmi_available = 1;
			goto out;
		}
	}
	else {
		/*
		 * no iounmap() for that ioremap(); it would be a no-op, but
		 * it's so early in setup that sucker gets confused into doing
		 * what it shouldn't if we actually call it.
		 */
		p = dmi_ioremap(0xF0000, 0x10000);
		if (p == NULL)
			goto error;

		for (q = p; q < p + 0x10000; q += 16) {
			rc = dmi_present(q);
			if (!rc) {
				dmi_available = 1;
				dmi_iounmap(p, 0x10000);
				goto out;
			}
		}
		dmi_iounmap(p, 0x10000);
	}
 error:
	printk(KERN_INFO "DMI not present or invalid.\n");
 out:
	dmi_initialized = 1;
}

/**
 *	dmi_matches - check if dmi_system_id structure matches system DMI data
 *	@dmi: pointer to the dmi_system_id structure to check
 */
static bool dmi_matches(const struct dmi_system_id *dmi)
{
	int i;

	WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");

	for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
		int s = dmi->matches[i].slot;
		if (s == DMI_NONE)
			break;
		if (dmi_ident[s]
		    && strstr(dmi_ident[s], dmi->matches[i].substr))
			continue;
		/* No match */
		return false;
	}
	return true;
}

/**
 *	dmi_is_end_of_table - check for end-of-table marker
 *	@dmi: pointer to the dmi_system_id structure to check
 */
static bool dmi_is_end_of_table(const struct dmi_system_id *dmi)
{
	return dmi->matches[0].slot == DMI_NONE;
}

/**
 *	dmi_check_system - check system DMI data
 *	@list: array of dmi_system_id structures to match against
 *		All non-null elements of the list must match
 *		their slot's (field index's) data (i.e., each
 *		list string must be a substring of the specified
 *		DMI slot's string data) to be considered a
 *		successful match.
 *
 *	Walk the blacklist table running matching functions until someone
 *	returns non zero or we hit the end. Callback function is called for
 *	each successful match. Returns the number of matches.
 */
int dmi_check_system(const struct dmi_system_id *list)
{
	int count = 0;
	const struct dmi_system_id *d;

	for (d = list; !dmi_is_end_of_table(d); d++)
		if (dmi_matches(d)) {
			count++;
			if (d->callback && d->callback(d))
				break;
		}

	return count;
}
EXPORT_SYMBOL(dmi_check_system);

/**
 *	dmi_first_match - find dmi_system_id structure matching system DMI data
 *	@list: array of dmi_system_id structures to match against
 *		All non-null elements of the list must match
 *		their slot's (field index's) data (i.e., each
 *		list string must be a substring of the specified
 *		DMI slot's string data) to be considered a
 *		successful match.
 *
 *	Walk the blacklist table until the first match is found.  Return the
 *	pointer to the matching entry or NULL if there's no match.
 */
const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
{
	const struct dmi_system_id *d;

	for (d = list; !dmi_is_end_of_table(d); d++)
		if (dmi_matches(d))
			return d;

	return NULL;
}
EXPORT_SYMBOL(dmi_first_match);

/**
 *	dmi_get_system_info - return DMI data value
 *	@field: data index (see enum dmi_field)
 *
 *	Returns one DMI data value, can be used to perform
 *	complex DMI data checks.
 */
const char *dmi_get_system_info(int field)
{
	return dmi_ident[field];
}
EXPORT_SYMBOL(dmi_get_system_info);

/**
 * dmi_name_in_serial - Check if string is in the DMI product serial information
 * @str: string to check for
 */
int dmi_name_in_serial(const char *str)
{
	int f = DMI_PRODUCT_SERIAL;
	if (dmi_ident[f] && strstr(dmi_ident[f], str))
		return 1;
	return 0;
}

/**
 *	dmi_name_in_vendors - Check if string is in the DMI system or board vendor name
 *	@str: 	Case sensitive Name
 */
int dmi_name_in_vendors(const char *str)
{
	static int fields[] = { DMI_SYS_VENDOR, DMI_BOARD_VENDOR, DMI_NONE };
	int i;
	for (i = 0; fields[i] != DMI_NONE; i++) {
		int f = fields[i];
		if (dmi_ident[f] && strstr(dmi_ident[f], str))
			return 1;
	}
	return 0;
}
EXPORT_SYMBOL(dmi_name_in_vendors);

/**
 *	dmi_find_device - find onboard device by type/name
 *	@type: device type or %DMI_DEV_TYPE_ANY to match all device types
 *	@name: device name string or %NULL to match all
 *	@from: previous device found in search, or %NULL for new search.
 *
 *	Iterates through the list of known onboard devices. If a device is
 *	found with a matching @vendor and @device, a pointer to its device
 *	structure is returned.  Otherwise, %NULL is returned.
 *	A new search is initiated by passing %NULL as the @from argument.
 *	If @from is not %NULL, searches continue from next device.
 */
const struct dmi_device * dmi_find_device(int type, const char *name,
				    const struct dmi_device *from)
{
	const struct list_head *head = from ? &from->list : &dmi_devices;
	struct list_head *d;

	for(d = head->next; d != &dmi_devices; d = d->next) {
		const struct dmi_device *dev =
			list_entry(d, struct dmi_device, list);

		if (((type == DMI_DEV_TYPE_ANY) || (dev->type == type)) &&
		    ((name == NULL) || (strcmp(dev->name, name) == 0)))
			return dev;
	}

	return NULL;
}
EXPORT_SYMBOL(dmi_find_device);

/**
 *	dmi_get_date - parse a DMI date
 *	@field:	data index (see enum dmi_field)
 *	@yearp: optional out parameter for the year
 *	@monthp: optional out parameter for the month
 *	@dayp: optional out parameter for the day
 *
 *	The date field is assumed to be in the form resembling
 *	[mm[/dd]]/yy[yy] and the result is stored in the out
 *	parameters any or all of which can be omitted.
 *
 *	If the field doesn't exist, all out parameters are set to zero
 *	and false is returned.  Otherwise, true is returned with any
 *	invalid part of date set to zero.
 *
 *	On return, year, month and day are guaranteed to be in the
 *	range of [0,9999], [0,12] and [0,31] respectively.
 */
bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
{
	int year = 0, month = 0, day = 0;
	bool exists;
	const char *s, *y;
	char *e;

	s = dmi_get_system_info(field);
	exists = s;
	if (!exists)
		goto out;

	/*
	 * Determine year first.  We assume the date string resembles
	 * mm/dd/yy[yy] but the original code extracted only the year
	 * from the end.  Keep the behavior in the spirit of no
	 * surprises.
	 */
	y = strrchr(s, '/');
	if (!y)
		goto out;

	y++;
	year = simple_strtoul(y, &e, 10);
	if (y != e && year < 100) {	/* 2-digit year */
		year += 1900;
		if (year < 1996)	/* no dates < spec 1.0 */
			year += 100;
	}
	if (year > 9999)		/* year should fit in %04d */
		year = 0;

	/* parse the mm and dd */
	month = simple_strtoul(s, &e, 10);
	if (s == e || *e != '/' || !month || month > 12) {
		month = 0;
		goto out;
	}

	s = e + 1;
	day = simple_strtoul(s, &e, 10);
	if (s == y || s == e || *e != '/' || day > 31)
		day = 0;
out:
	if (yearp)
		*yearp = year;
	if (monthp)
		*monthp = month;
	if (dayp)
		*dayp = day;
	return exists;
}
EXPORT_SYMBOL(dmi_get_date);

/**
 *	dmi_walk - Walk the DMI table and get called back for every record
 *	@decode: Callback function
 *	@private_data: Private data to be passed to the callback function
 *
 *	Returns -1 when the DMI table can't be reached, 0 on success.
 */
int dmi_walk(void (*decode)(const struct dmi_header *, void *),
	     void *private_data)
{
	u8 *buf;

	if (!dmi_available)
		return -1;

	buf = ioremap(dmi_base, dmi_len);
	if (buf == NULL)
		return -1;

	dmi_table(buf, dmi_len, dmi_num, decode, private_data);

	iounmap(buf);
	return 0;
}
EXPORT_SYMBOL_GPL(dmi_walk);

/**
 * dmi_match - compare a string to the dmi field (if exists)
 * @f: DMI field identifier
 * @str: string to compare the DMI field to
 *
 * Returns true if the requested field equals to the str (including NULL).
 */
bool dmi_match(enum dmi_field f, const char *str)
{
	const char *info = dmi_get_system_info(f);

	if (info == NULL || str == NULL)
		return info == str;

	return !strcmp(info, str);
}
EXPORT_SYMBOL_GPL(dmi_match);