summaryrefslogtreecommitdiff
path: root/drivers/s390/cio/device.c
blob: 688945662c151e16abbc65074dba3b6ed0ac06c8 (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
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
/*
 *  drivers/s390/cio/device.c
 *  bus driver for ccw devices
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *			 IBM Corporation
 *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
 *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/workqueue.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/param.h>		/* HZ */

#include "cio.h"
#include "css.h"
#include "device.h"
#include "ioasm.h"

/******************* bus type handling ***********************/

/* The Linux driver model distinguishes between a bus type and
 * the bus itself. Of course we only have one channel
 * subsystem driver and one channel system per machine, but
 * we still use the abstraction. T.R. says it's a good idea. */
static int
ccw_bus_match (struct device * dev, struct device_driver * drv)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = to_ccwdrv(drv);
	const struct ccw_device_id *ids = cdrv->ids, *found;

	if (!ids)
		return 0;

	found = ccw_device_id_match(ids, &cdev->id);
	if (!found)
		return 0;

	cdev->id.driver_info = found->driver_info;

	return 1;
}

/* Store modalias string delimited by prefix/suffix string into buffer with
 * specified size. Return length of resulting string (excluding trailing '\0')
 * even if string doesn't fit buffer (snprintf semantics). */
static int snprint_alias(char *buf, size_t size, const char *prefix,
			 struct ccw_device_id *id, const char *suffix)
{
	int len;

	len = snprintf(buf, size, "%sccw:t%04Xm%02X", prefix, id->cu_type,
		       id->cu_model);
	if (len > size)
		return len;
	buf += len;
	size -= len;

	if (id->dev_type != 0)
		len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
				id->dev_model, suffix);
	else
		len += snprintf(buf, size, "dtdm%s", suffix);

	return len;
}

/* Set up environment variables for ccw device uevent. Return 0 on success,
 * non-zero otherwise. */
static int ccw_uevent(struct device *dev, char **envp, int num_envp,
		      char *buffer, int buffer_size)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);
	int i = 0;
	int len;

	/* CU_TYPE= */
	len = snprintf(buffer, buffer_size, "CU_TYPE=%04X", id->cu_type) + 1;
	if (len > buffer_size || i >= num_envp)
		return -ENOMEM;
	envp[i++] = buffer;
	buffer += len;
	buffer_size -= len;

	/* CU_MODEL= */
	len = snprintf(buffer, buffer_size, "CU_MODEL=%02X", id->cu_model) + 1;
	if (len > buffer_size || i >= num_envp)
		return -ENOMEM;
	envp[i++] = buffer;
	buffer += len;
	buffer_size -= len;

	/* The next two can be zero, that's ok for us */
	/* DEV_TYPE= */
	len = snprintf(buffer, buffer_size, "DEV_TYPE=%04X", id->dev_type) + 1;
	if (len > buffer_size || i >= num_envp)
		return -ENOMEM;
	envp[i++] = buffer;
	buffer += len;
	buffer_size -= len;

	/* DEV_MODEL= */
	len = snprintf(buffer, buffer_size, "DEV_MODEL=%02X",
			(unsigned char) id->dev_model) + 1;
	if (len > buffer_size || i >= num_envp)
		return -ENOMEM;
	envp[i++] = buffer;
	buffer += len;
	buffer_size -= len;

	/* MODALIAS=  */
	len = snprint_alias(buffer, buffer_size, "MODALIAS=", id, "") + 1;
	if (len > buffer_size || i >= num_envp)
		return -ENOMEM;
	envp[i++] = buffer;
	buffer += len;
	buffer_size -= len;

	envp[i] = NULL;

	return 0;
}

struct bus_type ccw_bus_type;

static int io_subchannel_probe (struct subchannel *);
static int io_subchannel_remove (struct subchannel *);
void io_subchannel_irq (struct device *);
static int io_subchannel_notify(struct device *, int);
static void io_subchannel_verify(struct device *);
static void io_subchannel_ioterm(struct device *);
static void io_subchannel_shutdown(struct subchannel *);

struct css_driver io_subchannel_driver = {
	.subchannel_type = SUBCHANNEL_TYPE_IO,
	.drv = {
		.name = "io_subchannel",
		.bus  = &css_bus_type,
	},
	.irq = io_subchannel_irq,
	.notify = io_subchannel_notify,
	.verify = io_subchannel_verify,
	.termination = io_subchannel_ioterm,
	.probe = io_subchannel_probe,
	.remove = io_subchannel_remove,
	.shutdown = io_subchannel_shutdown,
};

struct workqueue_struct *ccw_device_work;
struct workqueue_struct *ccw_device_notify_work;
wait_queue_head_t ccw_device_init_wq;
atomic_t ccw_device_init_count;

static int __init
init_ccw_bus_type (void)
{
	int ret;

	init_waitqueue_head(&ccw_device_init_wq);
	atomic_set(&ccw_device_init_count, 0);

	ccw_device_work = create_singlethread_workqueue("cio");
	if (!ccw_device_work)
		return -ENOMEM; /* FIXME: better errno ? */
	ccw_device_notify_work = create_singlethread_workqueue("cio_notify");
	if (!ccw_device_notify_work) {
		ret = -ENOMEM; /* FIXME: better errno ? */
		goto out_err;
	}
	slow_path_wq = create_singlethread_workqueue("kslowcrw");
	if (!slow_path_wq) {
		ret = -ENOMEM; /* FIXME: better errno ? */
		goto out_err;
	}
	if ((ret = bus_register (&ccw_bus_type)))
		goto out_err;

	if ((ret = driver_register(&io_subchannel_driver.drv)))
		goto out_err;

	wait_event(ccw_device_init_wq,
		   atomic_read(&ccw_device_init_count) == 0);
	flush_workqueue(ccw_device_work);
	return 0;
out_err:
	if (ccw_device_work)
		destroy_workqueue(ccw_device_work);
	if (ccw_device_notify_work)
		destroy_workqueue(ccw_device_notify_work);
	if (slow_path_wq)
		destroy_workqueue(slow_path_wq);
	return ret;
}

static void __exit
cleanup_ccw_bus_type (void)
{
	driver_unregister(&io_subchannel_driver.drv);
	bus_unregister(&ccw_bus_type);
	destroy_workqueue(ccw_device_notify_work);
	destroy_workqueue(ccw_device_work);
}

subsys_initcall(init_ccw_bus_type);
module_exit(cleanup_ccw_bus_type);

/************************ device handling **************************/

/*
 * A ccw_device has some interfaces in sysfs in addition to the
 * standard ones.
 * The following entries are designed to export the information which
 * resided in 2.4 in /proc/subchannels. Subchannel and device number
 * are obvious, so they don't have an entry :)
 * TODO: Split chpids and pimpampom up? Where is "in use" in the tree?
 */
static ssize_t
chpids_show (struct device * dev, struct device_attribute *attr, char * buf)
{
	struct subchannel *sch = to_subchannel(dev);
	struct ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int chp;

	for (chp = 0; chp < 8; chp++)
		ret += sprintf (buf+ret, "%02x ", ssd->chpid[chp]);

	ret += sprintf (buf+ret, "\n");
	return min((ssize_t)PAGE_SIZE, ret);
}

static ssize_t
pimpampom_show (struct device * dev, struct device_attribute *attr, char * buf)
{
	struct subchannel *sch = to_subchannel(dev);
	struct pmcw *pmcw = &sch->schib.pmcw;

	return sprintf (buf, "%02x %02x %02x\n",
			pmcw->pim, pmcw->pam, pmcw->pom);
}

static ssize_t
devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);

	if (id->dev_type != 0)
		return sprintf(buf, "%04x/%02x\n",
				id->dev_type, id->dev_model);
	else
		return sprintf(buf, "n/a\n");
}

static ssize_t
cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);

	return sprintf(buf, "%04x/%02x\n",
		       id->cu_type, id->cu_model);
}

static ssize_t
modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);
	int len;

	len = snprint_alias(buf, PAGE_SIZE, "", id, "\n") + 1;

	return len > PAGE_SIZE ? PAGE_SIZE : len;
}

static ssize_t
online_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);

	return sprintf(buf, cdev->online ? "1\n" : "0\n");
}

static void
ccw_device_remove_disconnected(struct ccw_device *cdev)
{
	struct subchannel *sch;
	/*
	 * Forced offline in disconnected state means
	 * 'throw away device'.
	 */
	sch = to_subchannel(cdev->dev.parent);
	css_sch_device_unregister(sch);
	/* Reset intparm to zeroes. */
	sch->schib.pmcw.intparm = 0;
	cio_modify(sch);
	put_device(&sch->dev);
}

int
ccw_device_set_offline(struct ccw_device *cdev)
{
	int ret;

	if (!cdev)
		return -ENODEV;
	if (!cdev->online || !cdev->drv)
		return -EINVAL;

	if (cdev->drv->set_offline) {
		ret = cdev->drv->set_offline(cdev);
		if (ret != 0)
			return ret;
	}
	cdev->online = 0;
	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_offline(cdev);
	if (ret == -ENODEV) {
		if (cdev->private->state != DEV_STATE_NOT_OPER) {
			cdev->private->state = DEV_STATE_OFFLINE;
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
		}
		spin_unlock_irq(cdev->ccwlock);
		return ret;
	}
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else {
		pr_debug("ccw_device_offline returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
		cdev->online = 1;
	}
 	return ret;
}

int
ccw_device_set_online(struct ccw_device *cdev)
{
	int ret;

	if (!cdev)
		return -ENODEV;
	if (cdev->online || !cdev->drv)
		return -EINVAL;

	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_online(cdev);
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else {
		pr_debug("ccw_device_online returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
		return ret;
	}
	if (cdev->private->state != DEV_STATE_ONLINE)
		return -ENODEV;
	if (!cdev->drv->set_online || cdev->drv->set_online(cdev) == 0) {
		cdev->online = 1;
		return 0;
	}
	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_offline(cdev);
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else 
		pr_debug("ccw_device_offline returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
	return (ret == 0) ? -ENODEV : ret;
}

static ssize_t
online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	int i, force, ret;
	char *tmp;

	if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
		return -EAGAIN;

	if (cdev->drv && !try_module_get(cdev->drv->owner)) {
		atomic_set(&cdev->private->onoff, 0);
		return -EINVAL;
	}
	if (!strncmp(buf, "force\n", count)) {
		force = 1;
		i = 1;
	} else {
		force = 0;
		i = simple_strtoul(buf, &tmp, 16);
	}
	if (i == 1) {
		/* Do device recognition, if needed. */
		if (cdev->id.cu_type == 0) {
			ret = ccw_device_recognition(cdev);
			if (ret) {
				printk(KERN_WARNING"Couldn't start recognition "
				       "for device %s (ret=%d)\n",
				       cdev->dev.bus_id, ret);
				goto out;
			}
			wait_event(cdev->private->wait_q,
				   cdev->private->flags.recog_done);
		}
		if (cdev->drv && cdev->drv->set_online)
			ccw_device_set_online(cdev);
	} else if (i == 0) {
		if (cdev->private->state == DEV_STATE_DISCONNECTED)
			ccw_device_remove_disconnected(cdev);
		else if (cdev->drv && cdev->drv->set_offline)
			ccw_device_set_offline(cdev);
	}
	if (force && cdev->private->state == DEV_STATE_BOXED) {
		ret = ccw_device_stlck(cdev);
		if (ret) {
			printk(KERN_WARNING"ccw_device_stlck for device %s "
			       "returned %d!\n", cdev->dev.bus_id, ret);
			goto out;
		}
		/* Do device recognition, if needed. */
		if (cdev->id.cu_type == 0) {
			cdev->private->state = DEV_STATE_NOT_OPER;
			ret = ccw_device_recognition(cdev);
			if (ret) {
				printk(KERN_WARNING"Couldn't start recognition "
				       "for device %s (ret=%d)\n",
				       cdev->dev.bus_id, ret);
				goto out;
			}
			wait_event(cdev->private->wait_q,
				   cdev->private->flags.recog_done);
		}
		if (cdev->drv && cdev->drv->set_online)
			ccw_device_set_online(cdev);
	}
	out:
	if (cdev->drv)
		module_put(cdev->drv->owner);
	atomic_set(&cdev->private->onoff, 0);
	return count;
}

static ssize_t
available_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct subchannel *sch;

	switch (cdev->private->state) {
	case DEV_STATE_BOXED:
		return sprintf(buf, "boxed\n");
	case DEV_STATE_DISCONNECTED:
	case DEV_STATE_DISCONNECTED_SENSE_ID:
	case DEV_STATE_NOT_OPER:
		sch = to_subchannel(dev->parent);
		if (!sch->lpm)
			return sprintf(buf, "no path\n");
		else
			return sprintf(buf, "no device\n");
	default:
		/* All other states considered fine. */
		return sprintf(buf, "good\n");
	}
}

static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
static DEVICE_ATTR(devtype, 0444, devtype_show, NULL);
static DEVICE_ATTR(cutype, 0444, cutype_show, NULL);
static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
static DEVICE_ATTR(online, 0644, online_show, online_store);
extern struct device_attribute dev_attr_cmb_enable;
static DEVICE_ATTR(availability, 0444, available_show, NULL);

static struct attribute * subch_attrs[] = {
	&dev_attr_chpids.attr,
	&dev_attr_pimpampom.attr,
	NULL,
};

static struct attribute_group subch_attr_group = {
	.attrs = subch_attrs,
};

static inline int
subchannel_add_files (struct device *dev)
{
	return sysfs_create_group(&dev->kobj, &subch_attr_group);
}

static struct attribute * ccwdev_attrs[] = {
	&dev_attr_devtype.attr,
	&dev_attr_cutype.attr,
	&dev_attr_modalias.attr,
	&dev_attr_online.attr,
	&dev_attr_cmb_enable.attr,
	&dev_attr_availability.attr,
	NULL,
};

static struct attribute_group ccwdev_attr_group = {
	.attrs = ccwdev_attrs,
};

static inline int
device_add_files (struct device *dev)
{
	return sysfs_create_group(&dev->kobj, &ccwdev_attr_group);
}

static inline void
device_remove_files(struct device *dev)
{
	sysfs_remove_group(&dev->kobj, &ccwdev_attr_group);
}

/* this is a simple abstraction for device_register that sets the
 * correct bus type and adds the bus specific files */
int
ccw_device_register(struct ccw_device *cdev)
{
	struct device *dev = &cdev->dev;
	int ret;

	dev->bus = &ccw_bus_type;

	if ((ret = device_add(dev)))
		return ret;

	set_bit(1, &cdev->private->registered);
	if ((ret = device_add_files(dev))) {
		if (test_and_clear_bit(1, &cdev->private->registered))
			device_del(dev);
	}
	return ret;
}

struct match_data {
	unsigned int devno;
	unsigned int ssid;
	struct ccw_device * sibling;
};

static int
match_devno(struct device * dev, void * data)
{
	struct match_data * d = (struct match_data *)data;
	struct ccw_device * cdev;

	cdev = to_ccwdev(dev);
	if ((cdev->private->state == DEV_STATE_DISCONNECTED) &&
	    (cdev->private->devno == d->devno) &&
	    (cdev->private->ssid == d->ssid) &&
	    (cdev != d->sibling)) {
		cdev->private->state = DEV_STATE_NOT_OPER;
		return 1;
	}
	return 0;
}

static struct ccw_device *
get_disc_ccwdev_by_devno(unsigned int devno, unsigned int ssid,
			 struct ccw_device *sibling)
{
	struct device *dev;
	struct match_data data;

	data.devno = devno;
	data.ssid = ssid;
	data.sibling = sibling;
	dev = bus_find_device(&ccw_bus_type, NULL, &data, match_devno);

	return dev ? to_ccwdev(dev) : NULL;
}

static void
ccw_device_add_changed(void *data)
{

	struct ccw_device *cdev;

	cdev = (struct ccw_device *)data;
	if (device_add(&cdev->dev)) {
		put_device(&cdev->dev);
		return;
	}
	set_bit(1, &cdev->private->registered);
	if (device_add_files(&cdev->dev)) {
		if (test_and_clear_bit(1, &cdev->private->registered))
			device_unregister(&cdev->dev);
	}
}

extern int css_get_ssd_info(struct subchannel *sch);

void
ccw_device_do_unreg_rereg(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int need_rename;

	cdev = (struct ccw_device *)data;
	sch = to_subchannel(cdev->dev.parent);
	if (cdev->private->devno != sch->schib.pmcw.dev) {
		/*
		 * The device number has changed. This is usually only when
		 * a device has been detached under VM and then re-appeared
		 * on another subchannel because of a different attachment
		 * order than before. Ideally, we should should just switch
		 * subchannels, but unfortunately, this is not possible with
		 * the current implementation.
		 * Instead, we search for the old subchannel for this device
		 * number and deregister so there are no collisions with the
		 * newly registered ccw_device.
		 * FIXME: Find another solution so the block layer doesn't
		 *        get possibly sick...
		 */
		struct ccw_device *other_cdev;

		need_rename = 1;
		other_cdev = get_disc_ccwdev_by_devno(sch->schib.pmcw.dev,
						      sch->schid.ssid, cdev);
		if (other_cdev) {
			struct subchannel *other_sch;

			other_sch = to_subchannel(other_cdev->dev.parent);
			if (get_device(&other_sch->dev)) {
				stsch(other_sch->schid, &other_sch->schib);
				if (other_sch->schib.pmcw.dnv) {
					other_sch->schib.pmcw.intparm = 0;
					cio_modify(other_sch);
				}
				css_sch_device_unregister(other_sch);
			}
		}
		/* Update ssd info here. */
		css_get_ssd_info(sch);
		cdev->private->devno = sch->schib.pmcw.dev;
	} else
		need_rename = 0;
	device_remove_files(&cdev->dev);
	if (test_and_clear_bit(1, &cdev->private->registered))
		device_del(&cdev->dev);
	if (need_rename)
		snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x",
			  sch->schid.ssid, sch->schib.pmcw.dev);
	PREPARE_WORK(&cdev->private->kick_work,
		     ccw_device_add_changed, (void *)cdev);
	queue_work(ccw_device_work, &cdev->private->kick_work);
}

static void
ccw_device_release(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = to_ccwdev(dev);
	kfree(cdev->private);
	kfree(cdev);
}

/*
 * Register recognized device.
 */
static void
io_subchannel_register(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int ret;
	unsigned long flags;

	cdev = (struct ccw_device *) data;
	sch = to_subchannel(cdev->dev.parent);

	if (klist_node_attached(&cdev->dev.knode_parent)) {
		bus_rescan_devices(&ccw_bus_type);
		goto out;
	}
	/* make it known to the system */
	ret = ccw_device_register(cdev);
	if (ret) {
		printk (KERN_WARNING "%s: could not register %s\n",
			__func__, cdev->dev.bus_id);
		put_device(&cdev->dev);
		spin_lock_irqsave(&sch->lock, flags);
		sch->dev.driver_data = NULL;
		spin_unlock_irqrestore(&sch->lock, flags);
		kfree (cdev->private);
		kfree (cdev);
		put_device(&sch->dev);
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
		return;
	}

	ret = subchannel_add_files(cdev->dev.parent);
	if (ret)
		printk(KERN_WARNING "%s: could not add attributes to %s\n",
		       __func__, sch->dev.bus_id);
	put_device(&cdev->dev);
out:
	cdev->private->flags.recog_done = 1;
	put_device(&sch->dev);
	wake_up(&cdev->private->wait_q);
	if (atomic_dec_and_test(&ccw_device_init_count))
		wake_up(&ccw_device_init_wq);
}

void
ccw_device_call_sch_unregister(void *data)
{
	struct ccw_device *cdev = data;
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	css_sch_device_unregister(sch);
	/* Reset intparm to zeroes. */
	sch->schib.pmcw.intparm = 0;
	cio_modify(sch);
	put_device(&cdev->dev);
	put_device(&sch->dev);
}

/*
 * subchannel recognition done. Called from the state machine.
 */
void
io_subchannel_recog_done(struct ccw_device *cdev)
{
	struct subchannel *sch;

	if (css_init_done == 0) {
		cdev->private->flags.recog_done = 1;
		return;
	}
	switch (cdev->private->state) {
	case DEV_STATE_NOT_OPER:
		cdev->private->flags.recog_done = 1;
		/* Remove device found not operational. */
		if (!get_device(&cdev->dev))
			break;
		sch = to_subchannel(cdev->dev.parent);
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_call_sch_unregister, (void *) cdev);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
		break;
	case DEV_STATE_BOXED:
		/* Device did not respond in time. */
	case DEV_STATE_OFFLINE:
		/* 
		 * We can't register the device in interrupt context so
		 * we schedule a work item.
		 */
		if (!get_device(&cdev->dev))
			break;
		PREPARE_WORK(&cdev->private->kick_work,
			     io_subchannel_register, (void *) cdev);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		break;
	}
}

static int
io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
{
	int rc;
	struct ccw_device_private *priv;

	sch->dev.driver_data = cdev;
	sch->driver = &io_subchannel_driver;
	cdev->ccwlock = &sch->lock;

	/* Init private data. */
	priv = cdev->private;
	priv->devno = sch->schib.pmcw.dev;
	priv->ssid = sch->schid.ssid;
	priv->sch_no = sch->schid.sch_no;
	priv->state = DEV_STATE_NOT_OPER;
	INIT_LIST_HEAD(&priv->cmb_list);
	init_waitqueue_head(&priv->wait_q);
	init_timer(&priv->timer);

	/* Set an initial name for the device. */
	snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x",
		  sch->schid.ssid, sch->schib.pmcw.dev);

	/* Increase counter of devices currently in recognition. */
	atomic_inc(&ccw_device_init_count);

	/* Start async. device sensing. */
	spin_lock_irq(&sch->lock);
	rc = ccw_device_recognition(cdev);
	spin_unlock_irq(&sch->lock);
	if (rc) {
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
	}
	return rc;
}

static int
io_subchannel_probe (struct subchannel *sch)
{
	struct ccw_device *cdev;
	int rc;
	unsigned long flags;

	if (sch->dev.driver_data) {
		/*
		 * This subchannel already has an associated ccw_device.
		 * Register it and exit. This happens for all early
		 * device, e.g. the console.
		 */
		cdev = sch->dev.driver_data;
		device_initialize(&cdev->dev);
		ccw_device_register(cdev);
		subchannel_add_files(&sch->dev);
		/*
		 * Check if the device is already online. If it is
		 * the reference count needs to be corrected
		 * (see ccw_device_online and css_init_done for the
		 * ugly details).
		 */
		if (cdev->private->state != DEV_STATE_NOT_OPER &&
		    cdev->private->state != DEV_STATE_OFFLINE &&
		    cdev->private->state != DEV_STATE_BOXED)
			get_device(&cdev->dev);
		return 0;
	}
	cdev = kzalloc (sizeof(*cdev), GFP_KERNEL);
	if (!cdev)
		return -ENOMEM;
	cdev->private = kzalloc(sizeof(struct ccw_device_private),
				GFP_KERNEL | GFP_DMA);
	if (!cdev->private) {
		kfree(cdev);
		return -ENOMEM;
	}
	atomic_set(&cdev->private->onoff, 0);
	cdev->dev.parent = &sch->dev;
	cdev->dev.release = ccw_device_release;
	INIT_LIST_HEAD(&cdev->private->kick_work.entry);
	/* Do first half of device_register. */
	device_initialize(&cdev->dev);

	if (!get_device(&sch->dev)) {
		if (cdev->dev.release)
			cdev->dev.release(&cdev->dev);
		return -ENODEV;
	}

	rc = io_subchannel_recog(cdev, sch);
	if (rc) {
		spin_lock_irqsave(&sch->lock, flags);
		sch->dev.driver_data = NULL;
		spin_unlock_irqrestore(&sch->lock, flags);
		if (cdev->dev.release)
			cdev->dev.release(&cdev->dev);
	}

	return rc;
}

static void
ccw_device_unregister(void *data)
{
	struct ccw_device *cdev;

	cdev = (struct ccw_device *)data;
	if (test_and_clear_bit(1, &cdev->private->registered))
		device_unregister(&cdev->dev);
	put_device(&cdev->dev);
}

static int
io_subchannel_remove (struct subchannel *sch)
{
	struct ccw_device *cdev;
	unsigned long flags;

	if (!sch->dev.driver_data)
		return 0;
	cdev = sch->dev.driver_data;
	/* Set ccw device to not operational and drop reference. */
	spin_lock_irqsave(cdev->ccwlock, flags);
	sch->dev.driver_data = NULL;
	cdev->private->state = DEV_STATE_NOT_OPER;
	spin_unlock_irqrestore(cdev->ccwlock, flags);
	/*
	 * Put unregistration on workqueue to avoid livelocks on the css bus
	 * semaphore.
	 */
	if (get_device(&cdev->dev)) {
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_unregister, (void *) cdev);
		queue_work(ccw_device_work, &cdev->private->kick_work);
	}
	return 0;
}

static int
io_subchannel_notify(struct device *dev, int event)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (!cdev)
		return 0;
	if (!cdev->drv)
		return 0;
	if (!cdev->online)
		return 0;
	return cdev->drv->notify ? cdev->drv->notify(cdev, event) : 0;
}

static void
io_subchannel_verify(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (cdev)
		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
}

static void
io_subchannel_ioterm(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (!cdev)
		return;
	cdev->private->state = DEV_STATE_CLEAR_VERIFY;
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
}

static void
io_subchannel_shutdown(struct subchannel *sch)
{
	struct ccw_device *cdev;
	int ret;

	cdev = sch->dev.driver_data;

	if (cio_is_console(sch->schid))
		return;
	if (!sch->schib.pmcw.ena)
		/* Nothing to do. */
		return;
	ret = cio_disable_subchannel(sch);
	if (ret != -EBUSY)
		/* Subchannel is disabled, we're done. */
		return;
	cdev->private->state = DEV_STATE_QUIESCE;
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
	ret = ccw_device_cancel_halt_clear(cdev);
	if (ret == -EBUSY) {
		ccw_device_set_timeout(cdev, HZ/10);
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	}
	cio_disable_subchannel(sch);
}

#ifdef CONFIG_CCW_CONSOLE
static struct ccw_device console_cdev;
static struct ccw_device_private console_private;
static int console_cdev_in_use;

static int
ccw_device_console_enable (struct ccw_device *cdev, struct subchannel *sch)
{
	int rc;

	/* Initialize the ccw_device structure. */
	cdev->dev.parent= &sch->dev;
	rc = io_subchannel_recog(cdev, sch);
	if (rc)
		return rc;

	/* Now wait for the async. recognition to come to an end. */
	spin_lock_irq(cdev->ccwlock);
	while (!dev_fsm_final_state(cdev))
		wait_cons_dev();
	rc = -EIO;
	if (cdev->private->state != DEV_STATE_OFFLINE)
		goto out_unlock;
	ccw_device_online(cdev);
	while (!dev_fsm_final_state(cdev))
		wait_cons_dev();
	if (cdev->private->state != DEV_STATE_ONLINE)
		goto out_unlock;
	rc = 0;
out_unlock:
	spin_unlock_irq(cdev->ccwlock);
	return 0;
}

struct ccw_device *
ccw_device_probe_console(void)
{
	struct subchannel *sch;
	int ret;

	if (xchg(&console_cdev_in_use, 1) != 0)
		return ERR_PTR(-EBUSY);
	sch = cio_probe_console();
	if (IS_ERR(sch)) {
		console_cdev_in_use = 0;
		return (void *) sch;
	}
	memset(&console_cdev, 0, sizeof(struct ccw_device));
	memset(&console_private, 0, sizeof(struct ccw_device_private));
	console_cdev.private = &console_private;
	ret = ccw_device_console_enable(&console_cdev, sch);
	if (ret) {
		cio_release_console();
		console_cdev_in_use = 0;
		return ERR_PTR(ret);
	}
	console_cdev.online = 1;
	return &console_cdev;
}
#endif

/*
 * get ccw_device matching the busid, but only if owned by cdrv
 */
static int
__ccwdev_check_busid(struct device *dev, void *id)
{
	char *bus_id;

	bus_id = (char *)id;

	return (strncmp(bus_id, dev->bus_id, BUS_ID_SIZE) == 0);
}


struct ccw_device *
get_ccwdev_by_busid(struct ccw_driver *cdrv, const char *bus_id)
{
	struct device *dev;
	struct device_driver *drv;

	drv = get_driver(&cdrv->driver);
	if (!drv)
		return NULL;

	dev = driver_find_device(drv, NULL, (void *)bus_id,
				 __ccwdev_check_busid);
	put_driver(drv);

	return dev ? to_ccwdev(dev) : NULL;
}

/************************** device driver handling ************************/

/* This is the implementation of the ccw_driver class. The probe, remove
 * and release methods are initially very similar to the device_driver
 * implementations, with the difference that they have ccw_device
 * arguments.
 *
 * A ccw driver also contains the information that is needed for
 * device matching.
 */
static int
ccw_device_probe (struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
	int ret;

	cdev->drv = cdrv; /* to let the driver call _set_online */

	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;

	if (ret) {
		cdev->drv = NULL;
		return ret;
	}

	return 0;
}

static int
ccw_device_remove (struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = cdev->drv;
	int ret;

	pr_debug("removing device %s\n", cdev->dev.bus_id);
	if (cdrv->remove)
		cdrv->remove(cdev);
	if (cdev->online) {
		cdev->online = 0;
		spin_lock_irq(cdev->ccwlock);
		ret = ccw_device_offline(cdev);
		spin_unlock_irq(cdev->ccwlock);
		if (ret == 0)
			wait_event(cdev->private->wait_q,
				   dev_fsm_final_state(cdev));
		else
			//FIXME: we can't fail!
			pr_debug("ccw_device_offline returned %d, device %s\n",
				 ret, cdev->dev.bus_id);
	}
	ccw_device_set_timeout(cdev, 0);
	cdev->drv = NULL;
	return 0;
}

struct bus_type ccw_bus_type = {
	.name   = "ccw",
	.match  = ccw_bus_match,
	.uevent = ccw_uevent,
	.probe  = ccw_device_probe,
	.remove = ccw_device_remove,
};

int
ccw_driver_register (struct ccw_driver *cdriver)
{
	struct device_driver *drv = &cdriver->driver;

	drv->bus = &ccw_bus_type;
	drv->name = cdriver->name;

	return driver_register(drv);
}

void
ccw_driver_unregister (struct ccw_driver *cdriver)
{
	driver_unregister(&cdriver->driver);
}

/* Helper func for qdio. */
struct subchannel_id
ccw_device_get_subchannel_id(struct ccw_device *cdev)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	return sch->schid;
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccw_device_set_online);
EXPORT_SYMBOL(ccw_device_set_offline);
EXPORT_SYMBOL(ccw_driver_register);
EXPORT_SYMBOL(ccw_driver_unregister);
EXPORT_SYMBOL(get_ccwdev_by_busid);
EXPORT_SYMBOL(ccw_bus_type);
EXPORT_SYMBOL(ccw_device_work);
EXPORT_SYMBOL(ccw_device_notify_work);
EXPORT_SYMBOL_GPL(ccw_device_get_subchannel_id);