summaryrefslogtreecommitdiffstats
path: root/drivers/isdn/gigaset/common.c
blob: 827c32c167951aa3235477992697909ccd770944 (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
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
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
/*
 * Stuff used by all variants of the driver
 *
 * Copyright (c) 2001 by Stefan Eilers,
 *                       Hansjoerg Lipp <hjlipp@web.de>,
 *                       Tilman Schmidt <tilman@imap.cc>.
 *
 * =====================================================================
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation; either version 2 of
 *	the License, or (at your option) any later version.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

/* Version Information */
#define DRIVER_AUTHOR "Hansjoerg Lipp <hjlipp@web.de>, Tilman Schmidt <tilman@imap.cc>, Stefan Eilers"
#define DRIVER_DESC "Driver for Gigaset 307x"

/* Module parameters */
int gigaset_debuglevel = DEBUG_DEFAULT;
EXPORT_SYMBOL_GPL(gigaset_debuglevel);
module_param_named(debug, gigaset_debuglevel, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug, "debug level");

/* driver state flags */
#define VALID_MINOR	0x01
#define VALID_ID	0x02

void gigaset_dbg_buffer(enum debuglevel level, const unsigned char *msg,
			size_t len, const unsigned char *buf)
{
	unsigned char outbuf[80];
	unsigned char c;
	size_t space = sizeof outbuf - 1;
	unsigned char *out = outbuf;
	size_t numin = len;

	while (numin--) {
		c = *buf++;
		if (c == '~' || c == '^' || c == '\\') {
			if (!space--)
				break;
			*out++ = '\\';
		}
		if (c & 0x80) {
			if (!space--)
				break;
			*out++ = '~';
			c ^= 0x80;
		}
		if (c < 0x20 || c == 0x7f) {
			if (!space--)
				break;
			*out++ = '^';
			c ^= 0x40;
		}
		if (!space--)
			break;
		*out++ = c;
	}
	*out = 0;

	gig_dbg(level, "%s (%u bytes): %s", msg, (unsigned) len, outbuf);
}
EXPORT_SYMBOL_GPL(gigaset_dbg_buffer);

static int setflags(struct cardstate *cs, unsigned flags, unsigned delay)
{
	int r;

	r = cs->ops->set_modem_ctrl(cs, cs->control_state, flags);
	cs->control_state = flags;
	if (r < 0)
		return r;

	if (delay) {
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(delay * HZ / 1000);
	}

	return 0;
}

int gigaset_enterconfigmode(struct cardstate *cs)
{
	int i, r;

	cs->control_state = TIOCM_RTS; //FIXME

	r = setflags(cs, TIOCM_DTR, 200);
	if (r < 0)
		goto error;
	r = setflags(cs, 0, 200);
	if (r < 0)
		goto error;
	for (i = 0; i < 5; ++i) {
		r = setflags(cs, TIOCM_RTS, 100);
		if (r < 0)
			goto error;
		r = setflags(cs, 0, 100);
		if (r < 0)
			goto error;
	}
	r = setflags(cs, TIOCM_RTS|TIOCM_DTR, 800);
	if (r < 0)
		goto error;

	return 0;

error:
	dev_err(cs->dev, "error %d on setuartbits\n", -r);
	cs->control_state = TIOCM_RTS|TIOCM_DTR; // FIXME is this a good value?
	cs->ops->set_modem_ctrl(cs, 0, TIOCM_RTS|TIOCM_DTR);

	return -1; //r
}

static int test_timeout(struct at_state_t *at_state)
{
	if (!at_state->timer_expires)
		return 0;

	if (--at_state->timer_expires) {
		gig_dbg(DEBUG_MCMD, "decreased timer of %p to %lu",
			at_state, at_state->timer_expires);
		return 0;
	}

	if (!gigaset_add_event(at_state->cs, at_state, EV_TIMEOUT, NULL,
			       at_state->timer_index, NULL)) {
		//FIXME what should we do?
	}

	return 1;
}

static void timer_tick(unsigned long data)
{
	struct cardstate *cs = (struct cardstate *) data;
	unsigned long flags;
	unsigned channel;
	struct at_state_t *at_state;
	int timeout = 0;

	spin_lock_irqsave(&cs->lock, flags);

	for (channel = 0; channel < cs->channels; ++channel)
		if (test_timeout(&cs->bcs[channel].at_state))
			timeout = 1;

	if (test_timeout(&cs->at_state))
		timeout = 1;

	list_for_each_entry(at_state, &cs->temp_at_states, list)
		if (test_timeout(at_state))
			timeout = 1;

	if (cs->running) {
		mod_timer(&cs->timer, jiffies + msecs_to_jiffies(GIG_TICK));
		if (timeout) {
			gig_dbg(DEBUG_CMD, "scheduling timeout");
			tasklet_schedule(&cs->event_tasklet);
		}
	}

	spin_unlock_irqrestore(&cs->lock, flags);
}

int gigaset_get_channel(struct bc_state *bcs)
{
	unsigned long flags;

	spin_lock_irqsave(&bcs->cs->lock, flags);
	if (bcs->use_count || !try_module_get(bcs->cs->driver->owner)) {
		gig_dbg(DEBUG_ANY, "could not allocate channel %d",
			bcs->channel);
		spin_unlock_irqrestore(&bcs->cs->lock, flags);
		return 0;
	}
	++bcs->use_count;
	bcs->busy = 1;
	gig_dbg(DEBUG_ANY, "allocated channel %d", bcs->channel);
	spin_unlock_irqrestore(&bcs->cs->lock, flags);
	return 1;
}

void gigaset_free_channel(struct bc_state *bcs)
{
	unsigned long flags;

	spin_lock_irqsave(&bcs->cs->lock, flags);
	if (!bcs->busy) {
		gig_dbg(DEBUG_ANY, "could not free channel %d", bcs->channel);
		spin_unlock_irqrestore(&bcs->cs->lock, flags);
		return;
	}
	--bcs->use_count;
	bcs->busy = 0;
	module_put(bcs->cs->driver->owner);
	gig_dbg(DEBUG_ANY, "freed channel %d", bcs->channel);
	spin_unlock_irqrestore(&bcs->cs->lock, flags);
}

int gigaset_get_channels(struct cardstate *cs)
{
	unsigned long flags;
	int i;

	spin_lock_irqsave(&cs->lock, flags);
	for (i = 0; i < cs->channels; ++i)
		if (cs->bcs[i].use_count) {
			spin_unlock_irqrestore(&cs->lock, flags);
			gig_dbg(DEBUG_ANY, "could not allocate all channels");
			return 0;
		}
	for (i = 0; i < cs->channels; ++i)
		++cs->bcs[i].use_count;
	spin_unlock_irqrestore(&cs->lock, flags);

	gig_dbg(DEBUG_ANY, "allocated all channels");

	return 1;
}

void gigaset_free_channels(struct cardstate *cs)
{
	unsigned long flags;
	int i;

	gig_dbg(DEBUG_ANY, "unblocking all channels");
	spin_lock_irqsave(&cs->lock, flags);
	for (i = 0; i < cs->channels; ++i)
		--cs->bcs[i].use_count;
	spin_unlock_irqrestore(&cs->lock, flags);
}

void gigaset_block_channels(struct cardstate *cs)
{
	unsigned long flags;
	int i;

	gig_dbg(DEBUG_ANY, "blocking all channels");
	spin_lock_irqsave(&cs->lock, flags);
	for (i = 0; i < cs->channels; ++i)
		++cs->bcs[i].use_count;
	spin_unlock_irqrestore(&cs->lock, flags);
}

static void clear_events(struct cardstate *cs)
{
	struct event_t *ev;
	unsigned head, tail;
	unsigned long flags;

	spin_lock_irqsave(&cs->ev_lock, flags);

	head = cs->ev_head;
	tail = cs->ev_tail;

	while (tail != head) {
		ev = cs->events + head;
		kfree(ev->ptr);
		head = (head + 1) % MAX_EVENTS;
	}

	cs->ev_head = tail;

	spin_unlock_irqrestore(&cs->ev_lock, flags);
}

struct event_t *gigaset_add_event(struct cardstate *cs,
				  struct at_state_t *at_state, int type,
				  void *ptr, int parameter, void *arg)
{
	unsigned long flags;
	unsigned next, tail;
	struct event_t *event = NULL;

	spin_lock_irqsave(&cs->ev_lock, flags);

	tail = cs->ev_tail;
	next = (tail + 1) % MAX_EVENTS;
	if (unlikely(next == cs->ev_head))
		err("event queue full");
	else {
		event = cs->events + tail;
		event->type = type;
		event->at_state = at_state;
		event->cid = -1;
		event->ptr = ptr;
		event->arg = arg;
		event->parameter = parameter;
		cs->ev_tail = next;
	}

	spin_unlock_irqrestore(&cs->ev_lock, flags);

	return event;
}
EXPORT_SYMBOL_GPL(gigaset_add_event);

static void free_strings(struct at_state_t *at_state)
{
	int i;

	for (i = 0; i < STR_NUM; ++i) {
		kfree(at_state->str_var[i]);
		at_state->str_var[i] = NULL;
	}
}

static void clear_at_state(struct at_state_t *at_state)
{
	free_strings(at_state);
}

static void dealloc_at_states(struct cardstate *cs)
{
	struct at_state_t *cur, *next;

	list_for_each_entry_safe(cur, next, &cs->temp_at_states, list) {
		list_del(&cur->list);
		free_strings(cur);
		kfree(cur);
	}
}

static void gigaset_freebcs(struct bc_state *bcs)
{
	int i;

	gig_dbg(DEBUG_INIT, "freeing bcs[%d]->hw", bcs->channel);
	if (!bcs->cs->ops->freebcshw(bcs)) {
		gig_dbg(DEBUG_INIT, "failed");
	}

	gig_dbg(DEBUG_INIT, "clearing bcs[%d]->at_state", bcs->channel);
	clear_at_state(&bcs->at_state);
	gig_dbg(DEBUG_INIT, "freeing bcs[%d]->skb", bcs->channel);

	if (bcs->skb)
		dev_kfree_skb(bcs->skb);
	for (i = 0; i < AT_NUM; ++i) {
		kfree(bcs->commands[i]);
		bcs->commands[i] = NULL;
	}
}

static struct cardstate *alloc_cs(struct gigaset_driver *drv)
{
	unsigned long flags;
	unsigned i;
	struct cardstate *cs;
	struct cardstate *ret = NULL;

	spin_lock_irqsave(&drv->lock, flags);
	if (drv->blocked)
		goto exit;
	for (i = 0; i < drv->minors; ++i) {
		cs = drv->cs + i;
		if (!(cs->flags & VALID_MINOR)) {
			cs->flags = VALID_MINOR;
			ret = cs;
			break;
		}
	}
exit:
	spin_unlock_irqrestore(&drv->lock, flags);
	return ret;
}

static void free_cs(struct cardstate *cs)
{
	cs->flags = 0;
}

static void make_valid(struct cardstate *cs, unsigned mask)
{
	unsigned long flags;
	struct gigaset_driver *drv = cs->driver;
	spin_lock_irqsave(&drv->lock, flags);
	cs->flags |= mask;
	spin_unlock_irqrestore(&drv->lock, flags);
}

static void make_invalid(struct cardstate *cs, unsigned mask)
{
	unsigned long flags;
	struct gigaset_driver *drv = cs->driver;
	spin_lock_irqsave(&drv->lock, flags);
	cs->flags &= ~mask;
	spin_unlock_irqrestore(&drv->lock, flags);
}

void gigaset_freecs(struct cardstate *cs)
{
	int i;
	unsigned long flags;

	if (!cs)
		return;

	mutex_lock(&cs->mutex);

	if (!cs->bcs)
		goto f_cs;
	if (!cs->inbuf)
		goto f_bcs;

	spin_lock_irqsave(&cs->lock, flags);
	cs->running = 0;
	spin_unlock_irqrestore(&cs->lock, flags); /* event handler and timer are
						     not rescheduled below */

	tasklet_kill(&cs->event_tasklet);
	del_timer_sync(&cs->timer);

	switch (cs->cs_init) {
	default:
		/* clear device sysfs */
		gigaset_free_dev_sysfs(cs);

		gigaset_if_free(cs);

		gig_dbg(DEBUG_INIT, "clearing hw");
		cs->ops->freecshw(cs);

		//FIXME cmdbuf

		/* fall through */
	case 2: /* error in initcshw */
		/* Deregister from LL */
		make_invalid(cs, VALID_ID);
		gig_dbg(DEBUG_INIT, "clearing iif");
		gigaset_i4l_cmd(cs, ISDN_STAT_UNLOAD);

		/* fall through */
	case 1: /* error when regestering to LL */
		gig_dbg(DEBUG_INIT, "clearing at_state");
		clear_at_state(&cs->at_state);
		dealloc_at_states(cs);

		/* fall through */
	case 0: /* error in one call to initbcs */
		for (i = 0; i < cs->channels; ++i) {
			gig_dbg(DEBUG_INIT, "clearing bcs[%d]", i);
			gigaset_freebcs(cs->bcs + i);
		}

		clear_events(cs);
		gig_dbg(DEBUG_INIT, "freeing inbuf");
		kfree(cs->inbuf);
	}
f_bcs:	gig_dbg(DEBUG_INIT, "freeing bcs[]");
	kfree(cs->bcs);
f_cs:	gig_dbg(DEBUG_INIT, "freeing cs");
	mutex_unlock(&cs->mutex);
	free_cs(cs);
}
EXPORT_SYMBOL_GPL(gigaset_freecs);

void gigaset_at_init(struct at_state_t *at_state, struct bc_state *bcs,
		     struct cardstate *cs, int cid)
{
	int i;

	INIT_LIST_HEAD(&at_state->list);
	at_state->waiting = 0;
	at_state->getstring = 0;
	at_state->pending_commands = 0;
	at_state->timer_expires = 0;
	at_state->timer_active = 0;
	at_state->timer_index = 0;
	at_state->seq_index = 0;
	at_state->ConState = 0;
	for (i = 0; i < STR_NUM; ++i)
		at_state->str_var[i] = NULL;
	at_state->int_var[VAR_ZDLE] = 0;
	at_state->int_var[VAR_ZCTP] = -1;
	at_state->int_var[VAR_ZSAU] = ZSAU_NULL;
	at_state->cs = cs;
	at_state->bcs = bcs;
	at_state->cid = cid;
	if (!cid)
		at_state->replystruct = cs->tabnocid;
	else
		at_state->replystruct = cs->tabcid;
}


static void gigaset_inbuf_init(struct inbuf_t *inbuf, struct bc_state *bcs,
			       struct cardstate *cs, int inputstate)
/* inbuf->read must be allocated before! */
{
	inbuf->head = 0;
	inbuf->tail = 0;
	inbuf->cs = cs;
	inbuf->bcs = bcs; /*base driver: NULL*/
	inbuf->rcvbuf = NULL;
	inbuf->inputstate = inputstate;
}

/* append received bytes to inbuf */
int gigaset_fill_inbuf(struct inbuf_t *inbuf, const unsigned char *src,
		       unsigned numbytes)
{
	unsigned n, head, tail, bytesleft;

	gig_dbg(DEBUG_INTR, "received %u bytes", numbytes);

	if (!numbytes)
		return 0;

	bytesleft = numbytes;
	tail = inbuf->tail;
	head = inbuf->head;
	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);

	while (bytesleft) {
		if (head > tail)
			n = head - 1 - tail;
		else if (head == 0)
			n = (RBUFSIZE-1) - tail;
		else
			n = RBUFSIZE - tail;
		if (!n) {
			dev_err(inbuf->cs->dev,
				"buffer overflow (%u bytes lost)\n",
				bytesleft);
			break;
		}
		if (n > bytesleft)
			n = bytesleft;
		memcpy(inbuf->data + tail, src, n);
		bytesleft -= n;
		tail = (tail + n) % RBUFSIZE;
		src += n;
	}
	gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
	inbuf->tail = tail;
	return numbytes != bytesleft;
}
EXPORT_SYMBOL_GPL(gigaset_fill_inbuf);

/* Initialize the b-channel structure */
static struct bc_state *gigaset_initbcs(struct bc_state *bcs,
					struct cardstate *cs, int channel)
{
	int i;

	bcs->tx_skb = NULL; //FIXME -> hw part

	skb_queue_head_init(&bcs->squeue);

	bcs->corrupted = 0;
	bcs->trans_down = 0;
	bcs->trans_up = 0;

	gig_dbg(DEBUG_INIT, "setting up bcs[%d]->at_state", channel);
	gigaset_at_init(&bcs->at_state, bcs, cs, -1);

	bcs->rcvbytes = 0;

#ifdef CONFIG_GIGASET_DEBUG
	bcs->emptycount = 0;
#endif

	gig_dbg(DEBUG_INIT, "allocating bcs[%d]->skb", channel);
	bcs->fcs = PPP_INITFCS;
	bcs->inputstate = 0;
	if (cs->ignoreframes) {
		bcs->inputstate |= INS_skip_frame;
		bcs->skb = NULL;
	} else if ((bcs->skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)
		skb_reserve(bcs->skb, HW_HDR_LEN);
	else {
		warn("could not allocate skb");
		bcs->inputstate |= INS_skip_frame;
	}

	bcs->channel = channel;
	bcs->cs = cs;

	bcs->chstate = 0;
	bcs->use_count = 1;
	bcs->busy = 0;
	bcs->ignore = cs->ignoreframes;

	for (i = 0; i < AT_NUM; ++i)
		bcs->commands[i] = NULL;

	gig_dbg(DEBUG_INIT, "  setting up bcs[%d]->hw", channel);
	if (cs->ops->initbcshw(bcs))
		return bcs;

	gig_dbg(DEBUG_INIT, "  failed");

	gig_dbg(DEBUG_INIT, "  freeing bcs[%d]->skb", channel);
	if (bcs->skb)
		dev_kfree_skb(bcs->skb);

	return NULL;
}

/* gigaset_initcs
 * Allocate and initialize cardstate structure for Gigaset driver
 * Calls hardware dependent gigaset_initcshw() function
 * Calls B channel initialization function gigaset_initbcs() for each B channel
 * parameters:
 *	drv		hardware driver the device belongs to
 *	channels	number of B channels supported by device
 *	onechannel	!=0: B channel data and AT commands share one
 *			     communication channel
 *			==0: B channels have separate communication channels
 *	ignoreframes	number of frames to ignore after setting up B channel
 *	cidmode		!=0: start in CallID mode
 *	modulename	name of driver module (used for I4L registration)
 * return value:
 *	pointer to cardstate structure
 */
struct cardstate *gigaset_initcs(struct gigaset_driver *drv, int channels,
				 int onechannel, int ignoreframes,
				 int cidmode, const char *modulename)
{
	struct cardstate *cs = NULL;
	unsigned long flags;
	int i;

	gig_dbg(DEBUG_INIT, "allocating cs");
	if (!(cs = alloc_cs(drv))) {
		err("maximum number of devices exceeded");
		return NULL;
	}

	gig_dbg(DEBUG_INIT, "allocating bcs[0..%d]", channels - 1);
	cs->bcs = kmalloc(channels * sizeof(struct bc_state), GFP_KERNEL);
	if (!cs->bcs) {
		err("out of memory");
		goto error;
	}
	gig_dbg(DEBUG_INIT, "allocating inbuf");
	cs->inbuf = kmalloc(sizeof(struct inbuf_t), GFP_KERNEL);
	if (!cs->inbuf) {
		err("out of memory");
		goto error;
	}

	cs->cs_init = 0;
	cs->channels = channels;
	cs->onechannel = onechannel;
	cs->ignoreframes = ignoreframes;
	INIT_LIST_HEAD(&cs->temp_at_states);
	cs->running = 0;
	init_timer(&cs->timer); /* clear next & prev */
	spin_lock_init(&cs->ev_lock);
	cs->ev_tail = 0;
	cs->ev_head = 0;

	tasklet_init(&cs->event_tasklet, &gigaset_handle_event,
		     (unsigned long) cs);
	cs->commands_pending = 0;
	cs->cur_at_seq = 0;
	cs->gotfwver = -1;
	cs->open_count = 0;
	cs->dev = NULL;
	cs->tty = NULL;
	cs->tty_dev = NULL;
	cs->cidmode = cidmode != 0;

	//if(onechannel) { //FIXME
		cs->tabnocid = gigaset_tab_nocid_m10x;
		cs->tabcid = gigaset_tab_cid_m10x;
	//} else {
	//	cs->tabnocid = gigaset_tab_nocid;
	//	cs->tabcid = gigaset_tab_cid;
	//}

	init_waitqueue_head(&cs->waitqueue);
	cs->waiting = 0;

	cs->mode = M_UNKNOWN;
	cs->mstate = MS_UNINITIALIZED;

	for (i = 0; i < channels; ++i) {
		gig_dbg(DEBUG_INIT, "setting up bcs[%d].read", i);
		if (!gigaset_initbcs(cs->bcs + i, cs, i)) {
			err("could not allocate channel %d data", i);
			goto error;
		}
	}

	++cs->cs_init;

	gig_dbg(DEBUG_INIT, "setting up at_state");
	spin_lock_init(&cs->lock);
	gigaset_at_init(&cs->at_state, NULL, cs, 0);
	cs->dle = 0;
	cs->cbytes = 0;

	gig_dbg(DEBUG_INIT, "setting up inbuf");
	if (onechannel) {			//FIXME distinction necessary?
		gigaset_inbuf_init(cs->inbuf, cs->bcs, cs, INS_command);
	} else
		gigaset_inbuf_init(cs->inbuf, NULL,    cs, INS_command);

	cs->connected = 0;
	cs->isdn_up = 0;

	gig_dbg(DEBUG_INIT, "setting up cmdbuf");
	cs->cmdbuf = cs->lastcmdbuf = NULL;
	spin_lock_init(&cs->cmdlock);
	cs->curlen = 0;
	cs->cmdbytes = 0;

	gig_dbg(DEBUG_INIT, "setting up iif");
	if (!gigaset_register_to_LL(cs, modulename)) {
		err("register_isdn failed");
		goto error;
	}

	make_valid(cs, VALID_ID);
	++cs->cs_init;
	gig_dbg(DEBUG_INIT, "setting up hw");
	if (!cs->ops->initcshw(cs)) {
		err("could not allocate device specific data");
		goto error;
	}

	++cs->cs_init;

	/* set up character device */
	gigaset_if_init(cs);

	/* set up device sysfs */
	gigaset_init_dev_sysfs(cs);

	spin_lock_irqsave(&cs->lock, flags);
	cs->running = 1;
	spin_unlock_irqrestore(&cs->lock, flags);
	setup_timer(&cs->timer, timer_tick, (unsigned long) cs);
	cs->timer.expires = jiffies + msecs_to_jiffies(GIG_TICK);
	/* FIXME: can jiffies increase too much until the timer is added?
	 * Same problem(?) with mod_timer() in timer_tick(). */
	add_timer(&cs->timer);

	gig_dbg(DEBUG_INIT, "cs initialized");
	return cs;

error:
	gig_dbg(DEBUG_INIT, "failed");
	gigaset_freecs(cs);
	return NULL;
}
EXPORT_SYMBOL_GPL(gigaset_initcs);

/* ReInitialize the b-channel structure on hangup */
void gigaset_bcs_reinit(struct bc_state *bcs)
{
	struct sk_buff *skb;
	struct cardstate *cs = bcs->cs;
	unsigned long flags;

	while ((skb = skb_dequeue(&bcs->squeue)) != NULL)
		dev_kfree_skb(skb);

	spin_lock_irqsave(&cs->lock, flags);
	clear_at_state(&bcs->at_state);
	bcs->at_state.ConState = 0;
	bcs->at_state.timer_active = 0;
	bcs->at_state.timer_expires = 0;
	bcs->at_state.cid = -1;			/* No CID defined */
	spin_unlock_irqrestore(&cs->lock, flags);

	bcs->inputstate = 0;

#ifdef CONFIG_GIGASET_DEBUG
	bcs->emptycount = 0;
#endif

	bcs->fcs = PPP_INITFCS;
	bcs->chstate = 0;

	bcs->ignore = cs->ignoreframes;
	if (bcs->ignore)
		bcs->inputstate |= INS_skip_frame;


	cs->ops->reinitbcshw(bcs);
}

static void cleanup_cs(struct cardstate *cs)
{
	struct cmdbuf_t *cb, *tcb;
	int i;
	unsigned long flags;

	spin_lock_irqsave(&cs->lock, flags);

	cs->mode = M_UNKNOWN;
	cs->mstate = MS_UNINITIALIZED;

	clear_at_state(&cs->at_state);
	dealloc_at_states(cs);
	free_strings(&cs->at_state);
	gigaset_at_init(&cs->at_state, NULL, cs, 0);

	kfree(cs->inbuf->rcvbuf);
	cs->inbuf->rcvbuf = NULL;
	cs->inbuf->inputstate = INS_command;
	cs->inbuf->head = 0;
	cs->inbuf->tail = 0;

	cb = cs->cmdbuf;
	while (cb) {
		tcb = cb;
		cb = cb->next;
		kfree(tcb);
	}
	cs->cmdbuf = cs->lastcmdbuf = NULL;
	cs->curlen = 0;
	cs->cmdbytes = 0;
	cs->gotfwver = -1;
	cs->dle = 0;
	cs->cur_at_seq = 0;
	cs->commands_pending = 0;
	cs->cbytes = 0;

	spin_unlock_irqrestore(&cs->lock, flags);

	for (i = 0; i < cs->channels; ++i) {
		gigaset_freebcs(cs->bcs + i);
		if (!gigaset_initbcs(cs->bcs + i, cs, i))
			break;			//FIXME error handling
	}

	if (cs->waiting) {
		cs->cmd_result = -ENODEV;
		cs->waiting = 0;
		wake_up_interruptible(&cs->waitqueue);
	}
}


int gigaset_start(struct cardstate *cs)
{
	unsigned long flags;

	if (mutex_lock_interruptible(&cs->mutex))
		return 0;

	spin_lock_irqsave(&cs->lock, flags);
	cs->connected = 1;
	spin_unlock_irqrestore(&cs->lock, flags);

	if (cs->mstate != MS_LOCKED) {
		cs->ops->set_modem_ctrl(cs, 0, TIOCM_DTR|TIOCM_RTS);
		cs->ops->baud_rate(cs, B115200);
		cs->ops->set_line_ctrl(cs, CS8);
		cs->control_state = TIOCM_DTR|TIOCM_RTS;
	} else {
		//FIXME use some saved values?
	}

	cs->waiting = 1;

	if (!gigaset_add_event(cs, &cs->at_state, EV_START, NULL, 0, NULL)) {
		cs->waiting = 0;
		//FIXME what should we do?
		goto error;
	}

	gig_dbg(DEBUG_CMD, "scheduling START");
	gigaset_schedule_event(cs);

	wait_event(cs->waitqueue, !cs->waiting);

	mutex_unlock(&cs->mutex);
	return 1;

error:
	mutex_unlock(&cs->mutex);
	return 0;
}
EXPORT_SYMBOL_GPL(gigaset_start);

/* gigaset_shutdown
 * check if a device is associated to the cardstate structure and stop it
 * return value: 0 if ok, -1 if no device was associated
 */
int gigaset_shutdown(struct cardstate *cs)
{
	mutex_lock(&cs->mutex);

	if (!(cs->flags & VALID_MINOR)) {
		mutex_unlock(&cs->mutex);
		return -1;
	}

	cs->waiting = 1;

	if (!gigaset_add_event(cs, &cs->at_state, EV_SHUTDOWN, NULL, 0, NULL)) {
		//FIXME what should we do?
		goto exit;
	}

	gig_dbg(DEBUG_CMD, "scheduling SHUTDOWN");
	gigaset_schedule_event(cs);

	wait_event(cs->waitqueue, !cs->waiting);

	cleanup_cs(cs);

exit:
	mutex_unlock(&cs->mutex);
	return 0;
}
EXPORT_SYMBOL_GPL(gigaset_shutdown);

void gigaset_stop(struct cardstate *cs)
{
	mutex_lock(&cs->mutex);

	cs->waiting = 1;

	if (!gigaset_add_event(cs, &cs->at_state, EV_STOP, NULL, 0, NULL)) {
		//FIXME what should we do?
		goto exit;
	}

	gig_dbg(DEBUG_CMD, "scheduling STOP");
	gigaset_schedule_event(cs);

	wait_event(cs->waitqueue, !cs->waiting);

	cleanup_cs(cs);

exit:
	mutex_unlock(&cs->mutex);
}
EXPORT_SYMBOL_GPL(gigaset_stop);

static LIST_HEAD(drivers);
static DEFINE_SPINLOCK(driver_lock);

struct cardstate *gigaset_get_cs_by_id(int id)
{
	unsigned long flags;
	struct cardstate *ret = NULL;
	struct cardstate *cs;
	struct gigaset_driver *drv;
	unsigned i;

	spin_lock_irqsave(&driver_lock, flags);
	list_for_each_entry(drv, &drivers, list) {
		spin_lock(&drv->lock);
		for (i = 0; i < drv->minors; ++i) {
			cs = drv->cs + i;
			if ((cs->flags & VALID_ID) && cs->myid == id) {
				ret = cs;
				break;
			}
		}
		spin_unlock(&drv->lock);
		if (ret)
			break;
	}
	spin_unlock_irqrestore(&driver_lock, flags);
	return ret;
}

void gigaset_debugdrivers(void)
{
	unsigned long flags;
	static struct cardstate *cs;
	struct gigaset_driver *drv;
	unsigned i;

	spin_lock_irqsave(&driver_lock, flags);
	list_for_each_entry(drv, &drivers, list) {
		gig_dbg(DEBUG_DRIVER, "driver %p", drv);
		spin_lock(&drv->lock);
		for (i = 0; i < drv->minors; ++i) {
			gig_dbg(DEBUG_DRIVER, "  index %u", i);
			cs = drv->cs + i;
			gig_dbg(DEBUG_DRIVER, "    cardstate %p", cs);
			gig_dbg(DEBUG_DRIVER, "    flags 0x%02x", cs->flags);
			gig_dbg(DEBUG_DRIVER, "    minor_index %u",
				cs->minor_index);
			gig_dbg(DEBUG_DRIVER, "    driver %p", cs->driver);
			gig_dbg(DEBUG_DRIVER, "    i4l id %d", cs->myid);
		}
		spin_unlock(&drv->lock);
	}
	spin_unlock_irqrestore(&driver_lock, flags);
}

static struct cardstate *gigaset_get_cs_by_minor(unsigned minor)
{
	unsigned long flags;
	struct cardstate *ret = NULL;
	struct gigaset_driver *drv;
	unsigned index;

	spin_lock_irqsave(&driver_lock, flags);
	list_for_each_entry(drv, &drivers, list) {
		if (minor < drv->minor || minor >= drv->minor + drv->minors)
			continue;
		index = minor - drv->minor;
		spin_lock(&drv->lock);
		if (drv->cs[index].flags & VALID_MINOR)
			ret = drv->cs + index;
		spin_unlock(&drv->lock);
		if (ret)
			break;
	}
	spin_unlock_irqrestore(&driver_lock, flags);
	return ret;
}

struct cardstate *gigaset_get_cs_by_tty(struct tty_struct *tty)
{
	if (tty->index < 0 || tty->index >= tty->driver->num)
		return NULL;
	return gigaset_get_cs_by_minor(tty->index + tty->driver->minor_start);
}

void gigaset_freedriver(struct gigaset_driver *drv)
{
	unsigned long flags;

	spin_lock_irqsave(&driver_lock, flags);
	list_del(&drv->list);
	spin_unlock_irqrestore(&driver_lock, flags);

	gigaset_if_freedriver(drv);

	kfree(drv->cs);
	kfree(drv);
}
EXPORT_SYMBOL_GPL(gigaset_freedriver);

/* gigaset_initdriver
 * Allocate and initialize gigaset_driver structure. Initialize interface.
 * parameters:
 *	minor		First minor number
 *	minors		Number of minors this driver can handle
 *	procname	Name of the driver
 *	devname		Name of the device files (prefix without minor number)
 * return value:
 *	Pointer to the gigaset_driver structure on success, NULL on failure.
 */
struct gigaset_driver *gigaset_initdriver(unsigned minor, unsigned minors,
					  const char *procname,
					  const char *devname,
					  const struct gigaset_ops *ops,
					  struct module *owner)
{
	struct gigaset_driver *drv;
	unsigned long flags;
	unsigned i;

	drv = kmalloc(sizeof *drv, GFP_KERNEL);
	if (!drv)
		return NULL;

	drv->have_tty = 0;
	drv->minor = minor;
	drv->minors = minors;
	spin_lock_init(&drv->lock);
	drv->blocked = 0;
	drv->ops = ops;
	drv->owner = owner;
	INIT_LIST_HEAD(&drv->list);

	drv->cs = kmalloc(minors * sizeof *drv->cs, GFP_KERNEL);
	if (!drv->cs)
		goto error;

	for (i = 0; i < minors; ++i) {
		drv->cs[i].flags = 0;
		drv->cs[i].driver = drv;
		drv->cs[i].ops = drv->ops;
		drv->cs[i].minor_index = i;
		mutex_init(&drv->cs[i].mutex);
	}

	gigaset_if_initdriver(drv, procname, devname);

	spin_lock_irqsave(&driver_lock, flags);
	list_add(&drv->list, &drivers);
	spin_unlock_irqrestore(&driver_lock, flags);

	return drv;

error:
	kfree(drv->cs);
	kfree(drv);
	return NULL;
}
EXPORT_SYMBOL_GPL(gigaset_initdriver);

void gigaset_blockdriver(struct gigaset_driver *drv)
{
	drv->blocked = 1;
}
EXPORT_SYMBOL_GPL(gigaset_blockdriver);

static int __init gigaset_init_module(void)
{
	/* in accordance with the principle of least astonishment,
	 * setting the 'debug' parameter to 1 activates a sensible
	 * set of default debug levels
	 */
	if (gigaset_debuglevel == 1)
		gigaset_debuglevel = DEBUG_DEFAULT;

	info(DRIVER_AUTHOR);
	info(DRIVER_DESC);
	return 0;
}

static void __exit gigaset_exit_module(void)
{
}

module_init(gigaset_init_module);
module_exit(gigaset_exit_module);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_LICENSE("GPL");