summaryrefslogblamecommitdiff
path: root/drivers/pnp/pnpbios/rsparser.c
blob: 9001b6f0204ddb75d681c3c898e3962b7bab408c (plain) (tree)
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
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797

































































                                                                                        
                                                 






                                                                             


                                                                         















































































































































































































































































































































































































































































































































































































































































































































                                                                                                               
/*
 * rsparser.c - parses and encodes pnpbios resource data streams
 *
 */

#include <linux/config.h>
#include <linux/ctype.h>
#include <linux/pnp.h>
#include <linux/pnpbios.h>

#ifdef CONFIG_PCI
#include <linux/pci.h>
#else
inline void pcibios_penalize_isa_irq(int irq) {}
#endif /* CONFIG_PCI */

#include "pnpbios.h"

/* standard resource tags */
#define SMALL_TAG_PNPVERNO		0x01
#define SMALL_TAG_LOGDEVID		0x02
#define SMALL_TAG_COMPATDEVID		0x03
#define SMALL_TAG_IRQ			0x04
#define SMALL_TAG_DMA			0x05
#define SMALL_TAG_STARTDEP		0x06
#define SMALL_TAG_ENDDEP		0x07
#define SMALL_TAG_PORT			0x08
#define SMALL_TAG_FIXEDPORT		0x09
#define SMALL_TAG_VENDOR		0x0e
#define SMALL_TAG_END			0x0f
#define LARGE_TAG			0x80
#define LARGE_TAG_MEM			0x81
#define LARGE_TAG_ANSISTR		0x82
#define LARGE_TAG_UNICODESTR		0x83
#define LARGE_TAG_VENDOR		0x84
#define LARGE_TAG_MEM32			0x85
#define LARGE_TAG_FIXEDMEM32		0x86

/*
 * Resource Data Stream Format:
 *
 * Allocated Resources (required)
 * end tag ->
 * Resource Configuration Options (optional)
 * end tag ->
 * Compitable Device IDs (optional)
 * final end tag ->
 */

/*
 * Allocated Resources
 */

static void
pnpbios_parse_allocated_irqresource(struct pnp_resource_table * res, int irq)
{
	int i = 0;
	while (!(res->irq_resource[i].flags & IORESOURCE_UNSET) && i < PNP_MAX_IRQ) i++;
	if (i < PNP_MAX_IRQ) {
		res->irq_resource[i].flags = IORESOURCE_IRQ;  // Also clears _UNSET flag
		if (irq == -1) {
			res->irq_resource[i].flags |= IORESOURCE_DISABLED;
			return;
		}
		res->irq_resource[i].start =
		res->irq_resource[i].end = (unsigned long) irq;
		pcibios_penalize_isa_irq(irq, 1);
	}
}

static void
pnpbios_parse_allocated_dmaresource(struct pnp_resource_table * res, int dma)
{
	int i = 0;
	while (i < PNP_MAX_DMA &&
			!(res->dma_resource[i].flags & IORESOURCE_UNSET))
		i++;
	if (i < PNP_MAX_DMA) {
		res->dma_resource[i].flags = IORESOURCE_DMA;  // Also clears _UNSET flag
		if (dma == -1) {
			res->dma_resource[i].flags |= IORESOURCE_DISABLED;
			return;
		}
		res->dma_resource[i].start =
		res->dma_resource[i].end = (unsigned long) dma;
	}
}

static void
pnpbios_parse_allocated_ioresource(struct pnp_resource_table * res, int io, int len)
{
	int i = 0;
	while (!(res->port_resource[i].flags & IORESOURCE_UNSET) && i < PNP_MAX_PORT) i++;
	if (i < PNP_MAX_PORT) {
		res->port_resource[i].flags = IORESOURCE_IO;  // Also clears _UNSET flag
		if (len <= 0 || (io + len -1) >= 0x10003) {
			res->port_resource[i].flags |= IORESOURCE_DISABLED;
			return;
		}
		res->port_resource[i].start = (unsigned long) io;
		res->port_resource[i].end = (unsigned long)(io + len - 1);
	}
}

static void
pnpbios_parse_allocated_memresource(struct pnp_resource_table * res, int mem, int len)
{
	int i = 0;
	while (!(res->mem_resource[i].flags & IORESOURCE_UNSET) && i < PNP_MAX_MEM) i++;
	if (i < PNP_MAX_MEM) {
		res->mem_resource[i].flags = IORESOURCE_MEM;  // Also clears _UNSET flag
		if (len <= 0) {
			res->mem_resource[i].flags |= IORESOURCE_DISABLED;
			return;
		}
		res->mem_resource[i].start = (unsigned long) mem;
		res->mem_resource[i].end = (unsigned long)(mem + len - 1);
	}
}

static unsigned char *
pnpbios_parse_allocated_resource_data(unsigned char * p, unsigned char * end, struct pnp_resource_table * res)
{
	unsigned int len, tag;
	int io, size, mask, i;

	if (!p)
		return NULL;

	/* Blank the resource table values */
	pnp_init_resource_table(res);

	while ((char *)p < (char *)end) {

		/* determine the type of tag */
		if (p[0] & LARGE_TAG) { /* large tag */
			len = (p[2] << 8) | p[1];
			tag = p[0];
		} else { /* small tag */
			len = p[0] & 0x07;
			tag = ((p[0]>>3) & 0x0f);
		}

		switch (tag) {

		case LARGE_TAG_MEM:
			if (len != 9)
				goto len_err;
			io = *(short *) &p[4];
			size = *(short *) &p[10];
			pnpbios_parse_allocated_memresource(res, io, size);
			break;

		case LARGE_TAG_ANSISTR:
			/* ignore this for now */
			break;

		case LARGE_TAG_VENDOR:
			/* do nothing */
			break;

		case LARGE_TAG_MEM32:
			if (len != 17)
				goto len_err;
			io = *(int *) &p[4];
			size = *(int *) &p[16];
			pnpbios_parse_allocated_memresource(res, io, size);
			break;

		case LARGE_TAG_FIXEDMEM32:
			if (len != 9)
				goto len_err;
			io = *(int *) &p[4];
			size = *(int *) &p[8];
			pnpbios_parse_allocated_memresource(res, io, size);
			break;

		case SMALL_TAG_IRQ:
			if (len < 2 || len > 3)
				goto len_err;
			io = -1;
			mask= p[1] + p[2]*256;
			for (i=0;i<16;i++, mask=mask>>1)
				if(mask & 0x01) io=i;
			pnpbios_parse_allocated_irqresource(res, io);
			break;

		case SMALL_TAG_DMA:
			if (len != 2)
				goto len_err;
			io = -1;
			mask = p[1];
			for (i=0;i<8;i++, mask = mask>>1)
				if(mask & 0x01) io=i;
			pnpbios_parse_allocated_dmaresource(res, io);
			break;

		case SMALL_TAG_PORT:
			if (len != 7)
				goto len_err;
			io = p[2] + p[3] *256;
			size = p[7];
			pnpbios_parse_allocated_ioresource(res, io, size);
			break;

		case SMALL_TAG_VENDOR:
			/* do nothing */
			break;

		case SMALL_TAG_FIXEDPORT:
			if (len != 3)
				goto len_err;
			io = p[1] + p[2] * 256;
			size = p[3];
			pnpbios_parse_allocated_ioresource(res, io, size);
			break;

		case SMALL_TAG_END:
			p = p + 2;
        		return (unsigned char *)p;
			break;

		default: /* an unkown tag */
			len_err:
			printk(KERN_ERR "PnPBIOS: Unknown tag '0x%x', length '%d'.\n", tag, len);
			break;
		}

		/* continue to the next tag */
		if (p[0] & LARGE_TAG)
			p += len + 3;
		else
			p += len + 1;
	}

	printk(KERN_ERR "PnPBIOS: Resource structure does not contain an end tag.\n");

	return NULL;
}


/*
 * Resource Configuration Options
 */

static void
pnpbios_parse_mem_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_mem * mem;
	mem = pnpbios_kmalloc(sizeof(struct pnp_mem), GFP_KERNEL);
	if (!mem)
		return;
	mem->min = ((p[5] << 8) | p[4]) << 8;
	mem->max = ((p[7] << 8) | p[6]) << 8;
	mem->align = (p[9] << 8) | p[8];
	mem->size = ((p[11] << 8) | p[10]) << 8;
	mem->flags = p[3];
	pnp_register_mem_resource(option,mem);
	return;
}

static void
pnpbios_parse_mem32_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_mem * mem;
	mem = pnpbios_kmalloc(sizeof(struct pnp_mem), GFP_KERNEL);
	if (!mem)
		return;
	mem->min = (p[7] << 24) | (p[6] << 16) | (p[5] << 8) | p[4];
	mem->max = (p[11] << 24) | (p[10] << 16) | (p[9] << 8) | p[8];
	mem->align = (p[15] << 24) | (p[14] << 16) | (p[13] << 8) | p[12];
	mem->size = (p[19] << 24) | (p[18] << 16) | (p[17] << 8) | p[16];
	mem->flags = p[3];
	pnp_register_mem_resource(option,mem);
	return;
}

static void
pnpbios_parse_fixed_mem32_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_mem * mem;
	mem = pnpbios_kmalloc(sizeof(struct pnp_mem), GFP_KERNEL);
	if (!mem)
		return;
	mem->min = mem->max = (p[7] << 24) | (p[6] << 16) | (p[5] << 8) | p[4];
	mem->size = (p[11] << 24) | (p[10] << 16) | (p[9] << 8) | p[8];
	mem->align = 0;
	mem->flags = p[3];
	pnp_register_mem_resource(option,mem);
	return;
}

static void
pnpbios_parse_irq_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_irq * irq;
	unsigned long bits;

	irq = pnpbios_kmalloc(sizeof(struct pnp_irq), GFP_KERNEL);
	if (!irq)
		return;
	bits = (p[2] << 8) | p[1];
	bitmap_copy(irq->map, &bits, 16);
	if (size > 2)
		irq->flags = p[3];
	else
		irq->flags = IORESOURCE_IRQ_HIGHEDGE;
	pnp_register_irq_resource(option,irq);
	return;
}

static void
pnpbios_parse_dma_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_dma * dma;
	dma = pnpbios_kmalloc(sizeof(struct pnp_dma), GFP_KERNEL);
	if (!dma)
		return;
	dma->map = p[1];
	dma->flags = p[2];
	pnp_register_dma_resource(option,dma);
	return;
}

static void
pnpbios_parse_port_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_port * port;
	port = pnpbios_kmalloc(sizeof(struct pnp_port), GFP_KERNEL);
	if (!port)
		return;
	port->min = (p[3] << 8) | p[2];
	port->max = (p[5] << 8) | p[4];
	port->align = p[6];
	port->size = p[7];
	port->flags = p[1] ? PNP_PORT_FLAG_16BITADDR : 0;
	pnp_register_port_resource(option,port);
	return;
}

static void
pnpbios_parse_fixed_port_option(unsigned char *p, int size, struct pnp_option *option)
{
	struct pnp_port * port;
	port = pnpbios_kmalloc(sizeof(struct pnp_port), GFP_KERNEL);
	if (!port)
		return;
	port->min = port->max = (p[2] << 8) | p[1];
	port->size = p[3];
	port->align = 0;
	port->flags = PNP_PORT_FLAG_FIXED;
	pnp_register_port_resource(option,port);
	return;
}

static unsigned char *
pnpbios_parse_resource_option_data(unsigned char * p, unsigned char * end, struct pnp_dev *dev)
{
	unsigned int len, tag;
	int priority = 0;
	struct pnp_option *option, *option_independent;

	if (!p)
		return NULL;

	option_independent = option = pnp_register_independent_option(dev);
	if (!option)
		return NULL;

	while ((char *)p < (char *)end) {

		/* determine the type of tag */
		if (p[0] & LARGE_TAG) { /* large tag */
			len = (p[2] << 8) | p[1];
			tag = p[0];
		} else { /* small tag */
			len = p[0] & 0x07;
			tag = ((p[0]>>3) & 0x0f);
		}

		switch (tag) {

		case LARGE_TAG_MEM:
			if (len != 9)
				goto len_err;
			pnpbios_parse_mem_option(p, len, option);
			break;

		case LARGE_TAG_MEM32:
			if (len != 17)
				goto len_err;
			pnpbios_parse_mem32_option(p, len, option);
			break;

		case LARGE_TAG_FIXEDMEM32:
			if (len != 9)
				goto len_err;
			pnpbios_parse_fixed_mem32_option(p, len, option);
			break;

		case SMALL_TAG_IRQ:
			if (len < 2 || len > 3)
				goto len_err;
			pnpbios_parse_irq_option(p, len, option);
			break;

		case SMALL_TAG_DMA:
			if (len != 2)
				goto len_err;
			pnpbios_parse_dma_option(p, len, option);
			break;

		case SMALL_TAG_PORT:
			if (len != 7)
				goto len_err;
			pnpbios_parse_port_option(p, len, option);
			break;

		case SMALL_TAG_VENDOR:
			/* do nothing */
			break;

		case SMALL_TAG_FIXEDPORT:
			if (len != 3)
				goto len_err;
			pnpbios_parse_fixed_port_option(p, len, option);
			break;

		case SMALL_TAG_STARTDEP:
			if (len > 1)
				goto len_err;
			priority = 0x100 | PNP_RES_PRIORITY_ACCEPTABLE;
			if (len > 0)
				priority = 0x100 | p[1];
			option = pnp_register_dependent_option(dev, priority);
			if (!option)
				return NULL;
			break;

		case SMALL_TAG_ENDDEP:
			if (len != 0)
				goto len_err;
			if (option_independent == option)
				printk(KERN_WARNING "PnPBIOS: Missing SMALL_TAG_STARTDEP tag\n");
			option = option_independent;
			break;

		case SMALL_TAG_END:
			if (option_independent != option)
				printk(KERN_WARNING "PnPBIOS: Missing SMALL_TAG_ENDDEP tag\n");
			p = p + 2;
        		return (unsigned char *)p;
			break;

		default: /* an unkown tag */
			len_err:
			printk(KERN_ERR "PnPBIOS: Unknown tag '0x%x', length '%d'.\n", tag, len);
			break;
		}

		/* continue to the next tag */
		if (p[0] & LARGE_TAG)
			p += len + 3;
		else
			p += len + 1;
	}

	printk(KERN_ERR "PnPBIOS: Resource structure does not contain an end tag.\n");

	return NULL;
}


/*
 * Compatible Device IDs
 */

#define HEX(id,a) hex[((id)>>a) & 15]
#define CHAR(id,a) (0x40 + (((id)>>a) & 31))
//

void pnpid32_to_pnpid(u32 id, char *str)
{
	const char *hex = "0123456789abcdef";

	id = be32_to_cpu(id);
	str[0] = CHAR(id, 26);
	str[1] = CHAR(id, 21);
	str[2] = CHAR(id,16);
	str[3] = HEX(id, 12);
	str[4] = HEX(id, 8);
	str[5] = HEX(id, 4);
	str[6] = HEX(id, 0);
	str[7] = '\0';

	return;
}
//
#undef CHAR
#undef HEX

static unsigned char *
pnpbios_parse_compatible_ids(unsigned char *p, unsigned char *end, struct pnp_dev *dev)
{
	int len, tag;
	char id[8];
	struct pnp_id *dev_id;

	if (!p)
		return NULL;

	while ((char *)p < (char *)end) {

		/* determine the type of tag */
		if (p[0] & LARGE_TAG) { /* large tag */
			len = (p[2] << 8) | p[1];
			tag = p[0];
		} else { /* small tag */
			len = p[0] & 0x07;
			tag = ((p[0]>>3) & 0x0f);
		}

		switch (tag) {

		case LARGE_TAG_ANSISTR:
			strncpy(dev->name, p + 3, len >= PNP_NAME_LEN ? PNP_NAME_LEN - 2 : len);
			dev->name[len >= PNP_NAME_LEN ? PNP_NAME_LEN - 1 : len] = '\0';
			break;

		case SMALL_TAG_COMPATDEVID: /* compatible ID */
			if (len != 4)
				goto len_err;
			dev_id =  pnpbios_kmalloc(sizeof (struct pnp_id), GFP_KERNEL);
			if (!dev_id)
				return NULL;
			memset(dev_id, 0, sizeof(struct pnp_id));
			pnpid32_to_pnpid(p[1] | p[2] << 8 | p[3] << 16 | p[4] << 24,id);
			memcpy(&dev_id->id, id, 7);
			pnp_add_id(dev_id, dev);
			break;

		case SMALL_TAG_END:
			p = p + 2;
        		return (unsigned char *)p;
			break;

		default: /* an unkown tag */
			len_err:
			printk(KERN_ERR "PnPBIOS: Unknown tag '0x%x', length '%d'.\n", tag, len);
			break;
		}

		/* continue to the next tag */
		if (p[0] & LARGE_TAG)
			p += len + 3;
		else
			p += len + 1;
	}

	printk(KERN_ERR "PnPBIOS: Resource structure does not contain an end tag.\n");

	return NULL;
}


/*
 * Allocated Resource Encoding
 */

static void pnpbios_encode_mem(unsigned char *p, struct resource * res)
{
	unsigned long base = res->start;
	unsigned long len = res->end - res->start + 1;
	p[4] = (base >> 8) & 0xff;
	p[5] = ((base >> 8) >> 8) & 0xff;
	p[6] = (base >> 8) & 0xff;
	p[7] = ((base >> 8) >> 8) & 0xff;
	p[10] = (len >> 8) & 0xff;
	p[11] = ((len >> 8) >> 8) & 0xff;
	return;
}

static void pnpbios_encode_mem32(unsigned char *p, struct resource * res)
{
	unsigned long base = res->start;
	unsigned long len = res->end - res->start + 1;
	p[4] = base & 0xff;
	p[5] = (base >> 8) & 0xff;
	p[6] = (base >> 16) & 0xff;
	p[7] = (base >> 24) & 0xff;
	p[8] = base & 0xff;
	p[9] = (base >> 8) & 0xff;
	p[10] = (base >> 16) & 0xff;
	p[11] = (base >> 24) & 0xff;
	p[16] = len & 0xff;
	p[17] = (len >> 8) & 0xff;
	p[18] = (len >> 16) & 0xff;
	p[19] = (len >> 24) & 0xff;
	return;
}

static void pnpbios_encode_fixed_mem32(unsigned char *p, struct resource * res)
{	unsigned long base = res->start;
	unsigned long len = res->end - res->start + 1;
	p[4] = base & 0xff;
	p[5] = (base >> 8) & 0xff;
	p[6] = (base >> 16) & 0xff;
	p[7] = (base >> 24) & 0xff;
	p[8] = len & 0xff;
	p[9] = (len >> 8) & 0xff;
	p[10] = (len >> 16) & 0xff;
	p[11] = (len >> 24) & 0xff;
	return;
}

static void pnpbios_encode_irq(unsigned char *p, struct resource * res)
{
	unsigned long map = 0;
	map = 1 << res->start;
	p[1] = map & 0xff;
	p[2] = (map >> 8) & 0xff;
	return;
}

static void pnpbios_encode_dma(unsigned char *p, struct resource * res)
{
	unsigned long map = 0;
	map = 1 << res->start;
	p[1] = map & 0xff;
	return;
}

static void pnpbios_encode_port(unsigned char *p, struct resource * res)
{
	unsigned long base = res->start;
	unsigned long len = res->end - res->start + 1;
	p[2] = base & 0xff;
	p[3] = (base >> 8) & 0xff;
	p[4] = base & 0xff;
	p[5] = (base >> 8) & 0xff;
	p[7] = len & 0xff;
	return;
}

static void pnpbios_encode_fixed_port(unsigned char *p, struct resource * res)
{
	unsigned long base = res->start;
	unsigned long len = res->end - res->start + 1;
	p[1] = base & 0xff;
	p[2] = (base >> 8) & 0xff;
	p[3] = len & 0xff;
	return;
}

static unsigned char *
pnpbios_encode_allocated_resource_data(unsigned char * p, unsigned char * end, struct pnp_resource_table * res)
{
	unsigned int len, tag;
	int port = 0, irq = 0, dma = 0, mem = 0;

	if (!p)
		return NULL;

	while ((char *)p < (char *)end) {

		/* determine the type of tag */
		if (p[0] & LARGE_TAG) { /* large tag */
			len = (p[2] << 8) | p[1];
			tag = p[0];
		} else { /* small tag */
			len = p[0] & 0x07;
			tag = ((p[0]>>3) & 0x0f);
		}

		switch (tag) {

		case LARGE_TAG_MEM:
			if (len != 9)
				goto len_err;
			pnpbios_encode_mem(p, &res->mem_resource[mem]);
			mem++;
			break;

		case LARGE_TAG_MEM32:
			if (len != 17)
				goto len_err;
			pnpbios_encode_mem32(p, &res->mem_resource[mem]);
			mem++;
			break;

		case LARGE_TAG_FIXEDMEM32:
			if (len != 9)
				goto len_err;
			pnpbios_encode_fixed_mem32(p, &res->mem_resource[mem]);
			mem++;
			break;

		case SMALL_TAG_IRQ:
			if (len < 2 || len > 3)
				goto len_err;
			pnpbios_encode_irq(p, &res->irq_resource[irq]);
			irq++;
			break;

		case SMALL_TAG_DMA:
			if (len != 2)
				goto len_err;
			pnpbios_encode_dma(p, &res->dma_resource[dma]);
			dma++;
			break;

		case SMALL_TAG_PORT:
			if (len != 7)
				goto len_err;
			pnpbios_encode_port(p, &res->port_resource[port]);
			port++;
			break;

		case SMALL_TAG_VENDOR:
			/* do nothing */
			break;

		case SMALL_TAG_FIXEDPORT:
			if (len != 3)
				goto len_err;
			pnpbios_encode_fixed_port(p, &res->port_resource[port]);
			port++;
			break;

		case SMALL_TAG_END:
			p = p + 2;
        		return (unsigned char *)p;
			break;

		default: /* an unkown tag */
			len_err:
			printk(KERN_ERR "PnPBIOS: Unknown tag '0x%x', length '%d'.\n", tag, len);
			break;
		}

		/* continue to the next tag */
		if (p[0] & LARGE_TAG)
			p += len + 3;
		else
			p += len + 1;
	}

	printk(KERN_ERR "PnPBIOS: Resource structure does not contain an end tag.\n");

	return NULL;
}


/*
 * Core Parsing Functions
 */

int
pnpbios_parse_data_stream(struct pnp_dev *dev, struct pnp_bios_node * node)
{
	unsigned char * p = (char *)node->data;
	unsigned char * end = (char *)(node->data + node->size);
	p = pnpbios_parse_allocated_resource_data(p,end,&dev->res);
	if (!p)
		return -EIO;
	p = pnpbios_parse_resource_option_data(p,end,dev);
	if (!p)
		return -EIO;
	p = pnpbios_parse_compatible_ids(p,end,dev);
	if (!p)
		return -EIO;
	return 0;
}

int
pnpbios_read_resources_from_node(struct pnp_resource_table *res,
				 struct pnp_bios_node * node)
{
	unsigned char * p = (char *)node->data;
	unsigned char * end = (char *)(node->data + node->size);
	p = pnpbios_parse_allocated_resource_data(p,end,res);
	if (!p)
		return -EIO;
	return 0;
}

int
pnpbios_write_resources_to_node(struct pnp_resource_table *res,
				struct pnp_bios_node * node)
{
	unsigned char * p = (char *)node->data;
	unsigned char * end = (char *)(node->data + node->size);
	p = pnpbios_encode_allocated_resource_data(p,end,res);
	if (!p)
		return -EIO;
	return 0;
}