summaryrefslogtreecommitdiff
path: root/drivers/s390/cio/css.c
blob: 913b6ddd040b83f8aa2b284dc090a04070e6e3ad (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
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
// SPDX-License-Identifier: GPL-2.0
/*
 * driver for channel subsystem
 *
 * Copyright IBM Corp. 2002, 2010
 *
 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *	      Cornelia Huck (cornelia.huck@de.ibm.com)
 */

#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/export.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/genalloc.h>
#include <linux/dma-mapping.h>
#include <asm/isc.h>
#include <asm/crw.h>

#include "css.h"
#include "cio.h"
#include "blacklist.h"
#include "cio_debug.h"
#include "ioasm.h"
#include "chsc.h"
#include "device.h"
#include "idset.h"
#include "chp.h"

int css_init_done = 0;
int max_ssid;

#define MAX_CSS_IDX 0
struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
static struct bus_type css_bus_type;

int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
	struct subchannel_id schid;
	int ret;

	init_subchannel_id(&schid);
	do {
		do {
			ret = fn(schid, data);
			if (ret)
				break;
		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
		schid.sch_no = 0;
	} while (schid.ssid++ < max_ssid);
	return ret;
}

struct cb_data {
	void *data;
	struct idset *set;
	int (*fn_known_sch)(struct subchannel *, void *);
	int (*fn_unknown_sch)(struct subchannel_id, void *);
};

static int call_fn_known_sch(struct device *dev, void *data)
{
	struct subchannel *sch = to_subchannel(dev);
	struct cb_data *cb = data;
	int rc = 0;

	if (cb->set)
		idset_sch_del(cb->set, sch->schid);
	if (cb->fn_known_sch)
		rc = cb->fn_known_sch(sch, cb->data);
	return rc;
}

static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	int rc = 0;

	if (idset_sch_contains(cb->set, schid))
		rc = cb->fn_unknown_sch(schid, cb->data);
	return rc;
}

static int call_fn_all_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	struct subchannel *sch;
	int rc = 0;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		if (cb->fn_known_sch)
			rc = cb->fn_known_sch(sch, cb->data);
		put_device(&sch->dev);
	} else {
		if (cb->fn_unknown_sch)
			rc = cb->fn_unknown_sch(schid, cb->data);
	}

	return rc;
}

int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
			       int (*fn_unknown)(struct subchannel_id,
			       void *), void *data)
{
	struct cb_data cb;
	int rc;

	cb.data = data;
	cb.fn_known_sch = fn_known;
	cb.fn_unknown_sch = fn_unknown;

	if (fn_known && !fn_unknown) {
		/* Skip idset allocation in case of known-only loop. */
		cb.set = NULL;
		return bus_for_each_dev(&css_bus_type, NULL, &cb,
					call_fn_known_sch);
	}

	cb.set = idset_sch_new();
	if (!cb.set)
		/* fall back to brute force scanning in case of oom */
		return for_each_subchannel(call_fn_all_sch, &cb);

	idset_fill(cb.set);

	/* Process registered subchannels. */
	rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
	if (rc)
		goto out;
	/* Process unregistered subchannels. */
	if (fn_unknown)
		rc = for_each_subchannel(call_fn_unknown_sch, &cb);
out:
	idset_free(cb.set);

	return rc;
}

static void css_sch_todo(struct work_struct *work);

static int css_sch_create_locks(struct subchannel *sch)
{
	sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
	if (!sch->lock)
		return -ENOMEM;

	spin_lock_init(sch->lock);
	mutex_init(&sch->reg_mutex);

	return 0;
}

static void css_subchannel_release(struct device *dev)
{
	struct subchannel *sch = to_subchannel(dev);

	sch->config.intparm = 0;
	cio_commit_config(sch);
	kfree(sch->driver_override);
	kfree(sch->lock);
	kfree(sch);
}

static int css_validate_subchannel(struct subchannel_id schid,
				   struct schib *schib)
{
	int err;

	switch (schib->pmcw.st) {
	case SUBCHANNEL_TYPE_IO:
	case SUBCHANNEL_TYPE_MSG:
		if (!css_sch_is_valid(schib))
			err = -ENODEV;
		else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
			CIO_MSG_EVENT(6, "Blacklisted device detected "
				      "at devno %04X, subchannel set %x\n",
				      schib->pmcw.dev, schid.ssid);
			err = -ENODEV;
		} else
			err = 0;
		break;
	default:
		err = 0;
	}
	if (err)
		goto out;

	CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
		      schid.ssid, schid.sch_no, schib->pmcw.st);
out:
	return err;
}

struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
					struct schib *schib)
{
	struct subchannel *sch;
	int ret;

	ret = css_validate_subchannel(schid, schib);
	if (ret < 0)
		return ERR_PTR(ret);

	sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
	if (!sch)
		return ERR_PTR(-ENOMEM);

	sch->schid = schid;
	sch->schib = *schib;
	sch->st = schib->pmcw.st;

	ret = css_sch_create_locks(sch);
	if (ret)
		goto err;

	INIT_WORK(&sch->todo_work, css_sch_todo);
	sch->dev.release = &css_subchannel_release;
	sch->dev.dma_mask = &sch->dma_mask;
	device_initialize(&sch->dev);
	/*
	 * The physical addresses for some of the dma structures that can
	 * belong to a subchannel need to fit 31 bit width (e.g. ccw).
	 */
	ret = dma_set_coherent_mask(&sch->dev, DMA_BIT_MASK(31));
	if (ret)
		goto err;
	/*
	 * But we don't have such restrictions imposed on the stuff that
	 * is handled by the streaming API.
	 */
	ret = dma_set_mask(&sch->dev, DMA_BIT_MASK(64));
	if (ret)
		goto err;

	return sch;

err:
	kfree(sch);
	return ERR_PTR(ret);
}

static int css_sch_device_register(struct subchannel *sch)
{
	int ret;

	mutex_lock(&sch->reg_mutex);
	dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
		     sch->schid.sch_no);
	ret = device_add(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
	return ret;
}

/**
 * css_sch_device_unregister - unregister a subchannel
 * @sch: subchannel to be unregistered
 */
void css_sch_device_unregister(struct subchannel *sch)
{
	mutex_lock(&sch->reg_mutex);
	if (device_is_registered(&sch->dev))
		device_unregister(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
}
EXPORT_SYMBOL_GPL(css_sch_device_unregister);

static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
{
	int i;
	int mask;

	memset(ssd, 0, sizeof(struct chsc_ssd_info));
	ssd->path_mask = pmcw->pim;
	for (i = 0; i < 8; i++) {
		mask = 0x80 >> i;
		if (pmcw->pim & mask) {
			chp_id_init(&ssd->chpid[i]);
			ssd->chpid[i].id = pmcw->chpid[i];
		}
	}
}

static void ssd_register_chpids(struct chsc_ssd_info *ssd)
{
	int i;
	int mask;

	for (i = 0; i < 8; i++) {
		mask = 0x80 >> i;
		if (ssd->path_mask & mask)
			chp_new(ssd->chpid[i]);
	}
}

void css_update_ssd_info(struct subchannel *sch)
{
	int ret;

	ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
	if (ret)
		ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);

	ssd_register_chpids(&sch->ssd_info);
}

static ssize_t type_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct subchannel *sch = to_subchannel(dev);

	return sprintf(buf, "%01x\n", sch->st);
}

static DEVICE_ATTR_RO(type);

static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct subchannel *sch = to_subchannel(dev);

	return sprintf(buf, "css:t%01X\n", sch->st);
}

static DEVICE_ATTR_RO(modalias);

static ssize_t driver_override_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct subchannel *sch = to_subchannel(dev);
	int ret;

	ret = driver_set_override(dev, &sch->driver_override, buf, count);
	if (ret)
		return ret;

	return count;
}

static ssize_t driver_override_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct subchannel *sch = to_subchannel(dev);
	ssize_t len;

	device_lock(dev);
	len = snprintf(buf, PAGE_SIZE, "%s\n", sch->driver_override);
	device_unlock(dev);
	return len;
}
static DEVICE_ATTR_RW(driver_override);

static struct attribute *subch_attrs[] = {
	&dev_attr_type.attr,
	&dev_attr_modalias.attr,
	&dev_attr_driver_override.attr,
	NULL,
};

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

static const struct attribute_group *default_subch_attr_groups[] = {
	&subch_attr_group,
	NULL,
};

static ssize_t chpids_show(struct device *dev,
			   struct device_attribute *attr,
			   char *buf)
{
	struct subchannel *sch = to_subchannel(dev);
	struct chsc_ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int mask;
	int chp;

	for (chp = 0; chp < 8; chp++) {
		mask = 0x80 >> chp;
		if (ssd->path_mask & mask)
			ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
		else
			ret += sprintf(buf + ret, "00 ");
	}
	ret += sprintf(buf + ret, "\n");
	return ret;
}
static DEVICE_ATTR_RO(chpids);

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 DEVICE_ATTR_RO(pimpampom);

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

	if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
	    (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
		return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
				  pmcw->dev);
	else
		return sysfs_emit(buf, "none\n");
}
static DEVICE_ATTR_RO(dev_busid);

static struct attribute *io_subchannel_type_attrs[] = {
	&dev_attr_chpids.attr,
	&dev_attr_pimpampom.attr,
	&dev_attr_dev_busid.attr,
	NULL,
};
ATTRIBUTE_GROUPS(io_subchannel_type);

static const struct device_type io_subchannel_type = {
	.groups = io_subchannel_type_groups,
};

int css_register_subchannel(struct subchannel *sch)
{
	int ret;

	/* Initialize the subchannel structure */
	sch->dev.parent = &channel_subsystems[0]->device;
	sch->dev.bus = &css_bus_type;
	sch->dev.groups = default_subch_attr_groups;

	if (sch->st == SUBCHANNEL_TYPE_IO)
		sch->dev.type = &io_subchannel_type;

	css_update_ssd_info(sch);
	/* make it known to the system */
	ret = css_sch_device_register(sch);
	if (ret) {
		CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
			      sch->schid.ssid, sch->schid.sch_no, ret);
		return ret;
	}
	return ret;
}

static int css_probe_device(struct subchannel_id schid, struct schib *schib)
{
	struct subchannel *sch;
	int ret;

	sch = css_alloc_subchannel(schid, schib);
	if (IS_ERR(sch))
		return PTR_ERR(sch);

	ret = css_register_subchannel(sch);
	if (ret)
		put_device(&sch->dev);

	return ret;
}

static int
check_subchannel(struct device *dev, const void *data)
{
	struct subchannel *sch;
	struct subchannel_id *schid = (void *)data;

	sch = to_subchannel(dev);
	return schid_equal(&sch->schid, schid);
}

struct subchannel *
get_subchannel_by_schid(struct subchannel_id schid)
{
	struct device *dev;

	dev = bus_find_device(&css_bus_type, NULL,
			      &schid, check_subchannel);

	return dev ? to_subchannel(dev) : NULL;
}

/**
 * css_sch_is_valid() - check if a subchannel is valid
 * @schib: subchannel information block for the subchannel
 */
int css_sch_is_valid(struct schib *schib)
{
	if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
		return 0;
	if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
		return 0;
	return 1;
}
EXPORT_SYMBOL_GPL(css_sch_is_valid);

static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
{
	struct schib schib;
	int ccode;

	if (!slow) {
		/* Will be done on the slow path. */
		return -EAGAIN;
	}
	/*
	 * The first subchannel that is not-operational (ccode==3)
	 * indicates that there aren't any more devices available.
	 * If stsch gets an exception, it means the current subchannel set
	 * is not valid.
	 */
	ccode = stsch(schid, &schib);
	if (ccode)
		return (ccode == 3) ? -ENXIO : ccode;

	return css_probe_device(schid, &schib);
}

static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
{
	int ret = 0;

	if (sch->driver) {
		if (sch->driver->sch_event)
			ret = sch->driver->sch_event(sch, slow);
		else
			dev_dbg(&sch->dev,
				"Got subchannel machine check but "
				"no sch_event handler provided.\n");
	}
	if (ret != 0 && ret != -EAGAIN) {
		CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
			      sch->schid.ssid, sch->schid.sch_no, ret);
	}
	return ret;
}

static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
	struct subchannel *sch;
	int ret;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		ret = css_evaluate_known_subchannel(sch, slow);
		put_device(&sch->dev);
	} else
		ret = css_evaluate_new_subchannel(schid, slow);
	if (ret == -EAGAIN)
		css_schedule_eval(schid);
}

/**
 * css_sched_sch_todo - schedule a subchannel operation
 * @sch: subchannel
 * @todo: todo
 *
 * Schedule the operation identified by @todo to be performed on the slow path
 * workqueue. Do nothing if another operation with higher priority is already
 * scheduled. Needs to be called with subchannel lock held.
 */
void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
{
	CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
		      sch->schid.ssid, sch->schid.sch_no, todo);
	if (sch->todo >= todo)
		return;
	/* Get workqueue ref. */
	if (!get_device(&sch->dev))
		return;
	sch->todo = todo;
	if (!queue_work(cio_work_q, &sch->todo_work)) {
		/* Already queued, release workqueue ref. */
		put_device(&sch->dev);
	}
}
EXPORT_SYMBOL_GPL(css_sched_sch_todo);

static void css_sch_todo(struct work_struct *work)
{
	struct subchannel *sch;
	enum sch_todo todo;
	int ret;

	sch = container_of(work, struct subchannel, todo_work);
	/* Find out todo. */
	spin_lock_irq(sch->lock);
	todo = sch->todo;
	CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
		      sch->schid.sch_no, todo);
	sch->todo = SCH_TODO_NOTHING;
	spin_unlock_irq(sch->lock);
	/* Perform todo. */
	switch (todo) {
	case SCH_TODO_NOTHING:
		break;
	case SCH_TODO_EVAL:
		ret = css_evaluate_known_subchannel(sch, 1);
		if (ret == -EAGAIN) {
			spin_lock_irq(sch->lock);
			css_sched_sch_todo(sch, todo);
			spin_unlock_irq(sch->lock);
		}
		break;
	case SCH_TODO_UNREG:
		css_sch_device_unregister(sch);
		break;
	}
	/* Release workqueue ref. */
	put_device(&sch->dev);
}

static struct idset *slow_subchannel_set;
static DEFINE_SPINLOCK(slow_subchannel_lock);
static DECLARE_WAIT_QUEUE_HEAD(css_eval_wq);
static atomic_t css_eval_scheduled;

static int __init slow_subchannel_init(void)
{
	atomic_set(&css_eval_scheduled, 0);
	slow_subchannel_set = idset_sch_new();
	if (!slow_subchannel_set) {
		CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
		return -ENOMEM;
	}
	return 0;
}

static int slow_eval_known_fn(struct subchannel *sch, void *data)
{
	int eval;
	int rc;

	spin_lock_irq(&slow_subchannel_lock);
	eval = idset_sch_contains(slow_subchannel_set, sch->schid);
	idset_sch_del(slow_subchannel_set, sch->schid);
	spin_unlock_irq(&slow_subchannel_lock);
	if (eval) {
		rc = css_evaluate_known_subchannel(sch, 1);
		if (rc == -EAGAIN)
			css_schedule_eval(sch->schid);
		/*
		 * The loop might take long time for platforms with lots of
		 * known devices. Allow scheduling here.
		 */
		cond_resched();
	}
	return 0;
}

static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
{
	int eval;
	int rc = 0;

	spin_lock_irq(&slow_subchannel_lock);
	eval = idset_sch_contains(slow_subchannel_set, schid);
	idset_sch_del(slow_subchannel_set, schid);
	spin_unlock_irq(&slow_subchannel_lock);
	if (eval) {
		rc = css_evaluate_new_subchannel(schid, 1);
		switch (rc) {
		case -EAGAIN:
			css_schedule_eval(schid);
			rc = 0;
			break;
		case -ENXIO:
		case -ENOMEM:
		case -EIO:
			/* These should abort looping */
			spin_lock_irq(&slow_subchannel_lock);
			idset_sch_del_subseq(slow_subchannel_set, schid);
			spin_unlock_irq(&slow_subchannel_lock);
			break;
		default:
			rc = 0;
		}
		/* Allow scheduling here since the containing loop might
		 * take a while.  */
		cond_resched();
	}
	return rc;
}

static void css_slow_path_func(struct work_struct *unused)
{
	unsigned long flags;

	CIO_TRACE_EVENT(4, "slowpath");
	for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
				   NULL);
	spin_lock_irqsave(&slow_subchannel_lock, flags);
	if (idset_is_empty(slow_subchannel_set)) {
		atomic_set(&css_eval_scheduled, 0);
		wake_up(&css_eval_wq);
	}
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}

static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
struct workqueue_struct *cio_work_q;

void css_schedule_eval(struct subchannel_id schid)
{
	unsigned long flags;

	spin_lock_irqsave(&slow_subchannel_lock, flags);
	idset_sch_add(slow_subchannel_set, schid);
	atomic_set(&css_eval_scheduled, 1);
	queue_delayed_work(cio_work_q, &slow_path_work, 0);
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}

void css_schedule_eval_all(void)
{
	unsigned long flags;

	spin_lock_irqsave(&slow_subchannel_lock, flags);
	idset_fill(slow_subchannel_set);
	atomic_set(&css_eval_scheduled, 1);
	queue_delayed_work(cio_work_q, &slow_path_work, 0);
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}

static int __unset_registered(struct device *dev, void *data)
{
	struct idset *set = data;
	struct subchannel *sch = to_subchannel(dev);

	idset_sch_del(set, sch->schid);
	return 0;
}

static int __unset_online(struct device *dev, void *data)
{
	struct idset *set = data;
	struct subchannel *sch = to_subchannel(dev);
	struct ccw_device *cdev;

	if (sch->st == SUBCHANNEL_TYPE_IO) {
		cdev = sch_get_cdev(sch);
		if (cdev && cdev->online)
			idset_sch_del(set, sch->schid);
	}

	return 0;
}

void css_schedule_eval_cond(enum css_eval_cond cond, unsigned long delay)
{
	unsigned long flags;
	struct idset *set;

	/* Find unregistered subchannels. */
	set = idset_sch_new();
	if (!set) {
		/* Fallback. */
		css_schedule_eval_all();
		return;
	}
	idset_fill(set);
	switch (cond) {
	case CSS_EVAL_UNREG:
		bus_for_each_dev(&css_bus_type, NULL, set, __unset_registered);
		break;
	case CSS_EVAL_NOT_ONLINE:
		bus_for_each_dev(&css_bus_type, NULL, set, __unset_online);
		break;
	default:
		break;
	}

	/* Apply to slow_subchannel_set. */
	spin_lock_irqsave(&slow_subchannel_lock, flags);
	idset_add_set(slow_subchannel_set, set);
	atomic_set(&css_eval_scheduled, 1);
	queue_delayed_work(cio_work_q, &slow_path_work, delay);
	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
	idset_free(set);
}

void css_wait_for_slow_path(void)
{
	flush_workqueue(cio_work_q);
}

/* Schedule reprobing of all unregistered subchannels. */
void css_schedule_reprobe(void)
{
	/* Schedule with a delay to allow merging of subsequent calls. */
	css_schedule_eval_cond(CSS_EVAL_UNREG, 1 * HZ);
}
EXPORT_SYMBOL_GPL(css_schedule_reprobe);

/*
 * Called from the machine check handler for subchannel report words.
 */
static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
{
	struct subchannel_id mchk_schid;
	struct subchannel *sch;

	if (overflow) {
		css_schedule_eval_all();
		return;
	}
	CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
		      crw0->erc, crw0->rsid);
	if (crw1)
		CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
			      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
			      crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
			      crw1->anc, crw1->erc, crw1->rsid);
	init_subchannel_id(&mchk_schid);
	mchk_schid.sch_no = crw0->rsid;
	if (crw1)
		mchk_schid.ssid = (crw1->rsid >> 4) & 3;

	if (crw0->erc == CRW_ERC_PMOD) {
		sch = get_subchannel_by_schid(mchk_schid);
		if (sch) {
			css_update_ssd_info(sch);
			put_device(&sch->dev);
		}
	}
	/*
	 * Since we are always presented with IPI in the CRW, we have to
	 * use stsch() to find out if the subchannel in question has come
	 * or gone.
	 */
	css_evaluate_subchannel(mchk_schid, 0);
}

static void __init
css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
{
	struct cpuid cpu_id;

	if (css_general_characteristics.mcss) {
		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
		css->global_pgid.pgid_high.ext_cssid.cssid =
			css->id_valid ? css->cssid : 0;
	} else {
		css->global_pgid.pgid_high.cpu_addr = stap();
	}
	get_cpu_id(&cpu_id);
	css->global_pgid.cpu_id = cpu_id.ident;
	css->global_pgid.cpu_model = cpu_id.machine;
	css->global_pgid.tod_high = tod_high;
}

static void channel_subsystem_release(struct device *dev)
{
	struct channel_subsystem *css = to_css(dev);

	mutex_destroy(&css->mutex);
	kfree(css);
}

static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
			       char *buf)
{
	struct channel_subsystem *css = to_css(dev);

	if (!css->id_valid)
		return -EINVAL;

	return sprintf(buf, "%x\n", css->cssid);
}
static DEVICE_ATTR_RO(real_cssid);

static ssize_t rescan_store(struct device *dev, struct device_attribute *a,
			    const char *buf, size_t count)
{
	CIO_TRACE_EVENT(4, "usr-rescan");

	css_schedule_eval_all();
	css_complete_work();

	return count;
}
static DEVICE_ATTR_WO(rescan);

static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
			      char *buf)
{
	struct channel_subsystem *css = to_css(dev);
	int ret;

	mutex_lock(&css->mutex);
	ret = sprintf(buf, "%x\n", css->cm_enabled);
	mutex_unlock(&css->mutex);
	return ret;
}

static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
			       const char *buf, size_t count)
{
	struct channel_subsystem *css = to_css(dev);
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 16, &val);
	if (ret)
		return ret;
	mutex_lock(&css->mutex);
	switch (val) {
	case 0:
		ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
		break;
	case 1:
		ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
		break;
	default:
		ret = -EINVAL;
	}
	mutex_unlock(&css->mutex);
	return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(cm_enable);

static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
			      int index)
{
	return css_chsc_characteristics.secm ? attr->mode : 0;
}

static struct attribute *cssdev_attrs[] = {
	&dev_attr_real_cssid.attr,
	&dev_attr_rescan.attr,
	NULL,
};

static struct attribute_group cssdev_attr_group = {
	.attrs = cssdev_attrs,
};

static struct attribute *cssdev_cm_attrs[] = {
	&dev_attr_cm_enable.attr,
	NULL,
};

static struct attribute_group cssdev_cm_attr_group = {
	.attrs = cssdev_cm_attrs,
	.is_visible = cm_enable_mode,
};

static const struct attribute_group *cssdev_attr_groups[] = {
	&cssdev_attr_group,
	&cssdev_cm_attr_group,
	NULL,
};

static int __init setup_css(int nr)
{
	struct channel_subsystem *css;
	int ret;

	css = kzalloc(sizeof(*css), GFP_KERNEL);
	if (!css)
		return -ENOMEM;

	channel_subsystems[nr] = css;
	dev_set_name(&css->device, "css%x", nr);
	css->device.groups = cssdev_attr_groups;
	css->device.release = channel_subsystem_release;
	/*
	 * We currently allocate notifier bits with this (using
	 * css->device as the device argument with the DMA API)
	 * and are fine with 64 bit addresses.
	 */
	ret = dma_coerce_mask_and_coherent(&css->device, DMA_BIT_MASK(64));
	if (ret) {
		kfree(css);
		goto out_err;
	}

	mutex_init(&css->mutex);
	ret = chsc_get_cssid_iid(nr, &css->cssid, &css->iid);
	if (!ret) {
		css->id_valid = true;
		pr_info("Partition identifier %01x.%01x\n", css->cssid,
			css->iid);
	}
	css_generate_pgid(css, (u32) (get_tod_clock() >> 32));

	ret = device_register(&css->device);
	if (ret) {
		put_device(&css->device);
		goto out_err;
	}

	css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
					 GFP_KERNEL);
	if (!css->pseudo_subchannel) {
		device_unregister(&css->device);
		ret = -ENOMEM;
		goto out_err;
	}

	css->pseudo_subchannel->dev.parent = &css->device;
	css->pseudo_subchannel->dev.release = css_subchannel_release;
	mutex_init(&css->pseudo_subchannel->reg_mutex);
	ret = css_sch_create_locks(css->pseudo_subchannel);
	if (ret) {
		kfree(css->pseudo_subchannel);
		device_unregister(&css->device);
		goto out_err;
	}

	dev_set_name(&css->pseudo_subchannel->dev, "defunct");
	ret = device_register(&css->pseudo_subchannel->dev);
	if (ret) {
		put_device(&css->pseudo_subchannel->dev);
		device_unregister(&css->device);
		goto out_err;
	}

	return ret;
out_err:
	channel_subsystems[nr] = NULL;
	return ret;
}

static int css_reboot_event(struct notifier_block *this,
			    unsigned long event,
			    void *ptr)
{
	struct channel_subsystem *css;
	int ret;

	ret = NOTIFY_DONE;
	for_each_css(css) {
		mutex_lock(&css->mutex);
		if (css->cm_enabled)
			if (chsc_secm(css, 0))
				ret = NOTIFY_BAD;
		mutex_unlock(&css->mutex);
	}

	return ret;
}

static struct notifier_block css_reboot_notifier = {
	.notifier_call = css_reboot_event,
};

#define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
static struct gen_pool *cio_dma_pool;

/* Currently cio supports only a single css */
struct device *cio_get_dma_css_dev(void)
{
	return &channel_subsystems[0]->device;
}

struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
{
	struct gen_pool *gp_dma;
	void *cpu_addr;
	dma_addr_t dma_addr;
	int i;

	gp_dma = gen_pool_create(3, -1);
	if (!gp_dma)
		return NULL;
	for (i = 0; i < nr_pages; ++i) {
		cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
					      CIO_DMA_GFP);
		if (!cpu_addr)
			return gp_dma;
		gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
				  dma_addr, PAGE_SIZE, -1);
	}
	return gp_dma;
}

static void __gp_dma_free_dma(struct gen_pool *pool,
			      struct gen_pool_chunk *chunk, void *data)
{
	size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;

	dma_free_coherent((struct device *) data, chunk_size,
			 (void *) chunk->start_addr,
			 (dma_addr_t) chunk->phys_addr);
}

void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
{
	if (!gp_dma)
		return;
	/* this is quite ugly but no better idea */
	gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
	gen_pool_destroy(gp_dma);
}

static int cio_dma_pool_init(void)
{
	/* No need to free up the resources: compiled in */
	cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
	if (!cio_dma_pool)
		return -ENOMEM;
	return 0;
}

void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
			size_t size)
{
	dma_addr_t dma_addr;
	unsigned long addr;
	size_t chunk_size;

	if (!gp_dma)
		return NULL;
	addr = gen_pool_alloc(gp_dma, size);
	while (!addr) {
		chunk_size = round_up(size, PAGE_SIZE);
		addr = (unsigned long) dma_alloc_coherent(dma_dev,
					 chunk_size, &dma_addr, CIO_DMA_GFP);
		if (!addr)
			return NULL;
		gen_pool_add_virt(gp_dma, addr, dma_addr, chunk_size, -1);
		addr = gen_pool_alloc(gp_dma, size);
	}
	return (void *) addr;
}

void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
{
	if (!cpu_addr)
		return;
	memset(cpu_addr, 0, size);
	gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
}

/*
 * Allocate dma memory from the css global pool. Intended for memory not
 * specific to any single device within the css. The allocated memory
 * is not guaranteed to be 31-bit addressable.
 *
 * Caution: Not suitable for early stuff like console.
 */
void *cio_dma_zalloc(size_t size)
{
	return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
}

void cio_dma_free(void *cpu_addr, size_t size)
{
	cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
}

/*
 * Now that the driver core is running, we can setup our channel subsystem.
 * The struct subchannel's are created during probing.
 */
static int __init css_bus_init(void)
{
	int ret, i;

	ret = chsc_init();
	if (ret)
		return ret;

	chsc_determine_css_characteristics();
	/* Try to enable MSS. */
	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
	if (ret)
		max_ssid = 0;
	else /* Success. */
		max_ssid = __MAX_SSID;

	ret = slow_subchannel_init();
	if (ret)
		goto out;

	ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
	if (ret)
		goto out;

	if ((ret = bus_register(&css_bus_type)))
		goto out;

	/* Setup css structure. */
	for (i = 0; i <= MAX_CSS_IDX; i++) {
		ret = setup_css(i);
		if (ret)
			goto out_unregister;
	}
	ret = register_reboot_notifier(&css_reboot_notifier);
	if (ret)
		goto out_unregister;
	ret = cio_dma_pool_init();
	if (ret)
		goto out_unregister_rn;
	airq_init();
	css_init_done = 1;

	/* Enable default isc for I/O subchannels. */
	isc_register(IO_SCH_ISC);

	return 0;
out_unregister_rn:
	unregister_reboot_notifier(&css_reboot_notifier);
out_unregister:
	while (i-- > 0) {
		struct channel_subsystem *css = channel_subsystems[i];
		device_unregister(&css->pseudo_subchannel->dev);
		device_unregister(&css->device);
	}
	bus_unregister(&css_bus_type);
out:
	crw_unregister_handler(CRW_RSC_SCH);
	idset_free(slow_subchannel_set);
	chsc_init_cleanup();
	pr_alert("The CSS device driver initialization failed with "
		 "errno=%d\n", ret);
	return ret;
}

static void __init css_bus_cleanup(void)
{
	struct channel_subsystem *css;

	for_each_css(css) {
		device_unregister(&css->pseudo_subchannel->dev);
		device_unregister(&css->device);
	}
	bus_unregister(&css_bus_type);
	crw_unregister_handler(CRW_RSC_SCH);
	idset_free(slow_subchannel_set);
	chsc_init_cleanup();
	isc_unregister(IO_SCH_ISC);
}

static int __init channel_subsystem_init(void)
{
	int ret;

	ret = css_bus_init();
	if (ret)
		return ret;
	cio_work_q = create_singlethread_workqueue("cio");
	if (!cio_work_q) {
		ret = -ENOMEM;
		goto out_bus;
	}
	ret = io_subchannel_init();
	if (ret)
		goto out_wq;

	/* Register subchannels which are already in use. */
	cio_register_early_subchannels();
	/* Start initial subchannel evaluation. */
	css_schedule_eval_all();

	return ret;
out_wq:
	destroy_workqueue(cio_work_q);
out_bus:
	css_bus_cleanup();
	return ret;
}
subsys_initcall(channel_subsystem_init);

static int css_settle(struct device_driver *drv, void *unused)
{
	struct css_driver *cssdrv = to_cssdriver(drv);

	if (cssdrv->settle)
		return cssdrv->settle();
	return 0;
}

int css_complete_work(void)
{
	int ret;

	/* Wait for the evaluation of subchannels to finish. */
	ret = wait_event_interruptible(css_eval_wq,
				       atomic_read(&css_eval_scheduled) == 0);
	if (ret)
		return -EINTR;
	flush_workqueue(cio_work_q);
	/* Wait for the subchannel type specific initialization to finish */
	return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
}


/*
 * Wait for the initialization of devices to finish, to make sure we are
 * done with our setup if the search for the root device starts.
 */
static int __init channel_subsystem_init_sync(void)
{
	css_complete_work();
	return 0;
}
subsys_initcall_sync(channel_subsystem_init_sync);

#ifdef CONFIG_PROC_FS
static ssize_t cio_settle_write(struct file *file, const char __user *buf,
				size_t count, loff_t *ppos)
{
	int ret;

	/* Handle pending CRW's. */
	crw_wait_for_channel_report();
	ret = css_complete_work();

	return ret ? ret : count;
}

static const struct proc_ops cio_settle_proc_ops = {
	.proc_open	= nonseekable_open,
	.proc_write	= cio_settle_write,
	.proc_lseek	= no_llseek,
};

static int __init cio_settle_init(void)
{
	struct proc_dir_entry *entry;

	entry = proc_create("cio_settle", S_IWUSR, NULL, &cio_settle_proc_ops);
	if (!entry)
		return -ENOMEM;
	return 0;
}
device_initcall(cio_settle_init);
#endif /*CONFIG_PROC_FS*/

int sch_is_pseudo_sch(struct subchannel *sch)
{
	if (!sch->dev.parent)
		return 0;
	return sch == to_css(sch->dev.parent)->pseudo_subchannel;
}

static int css_bus_match(struct device *dev, struct device_driver *drv)
{
	struct subchannel *sch = to_subchannel(dev);
	struct css_driver *driver = to_cssdriver(drv);
	struct css_device_id *id;

	/* When driver_override is set, only bind to the matching driver */
	if (sch->driver_override && strcmp(sch->driver_override, drv->name))
		return 0;

	for (id = driver->subchannel_type; id->match_flags; id++) {
		if (sch->st == id->type)
			return 1;
	}

	return 0;
}

static int css_probe(struct device *dev)
{
	struct subchannel *sch;
	int ret;

	sch = to_subchannel(dev);
	sch->driver = to_cssdriver(dev->driver);
	ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
	if (ret)
		sch->driver = NULL;
	return ret;
}

static void css_remove(struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	if (sch->driver->remove)
		sch->driver->remove(sch);
	sch->driver = NULL;
}

static void css_shutdown(struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	if (sch->driver && sch->driver->shutdown)
		sch->driver->shutdown(sch);
}

static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct subchannel *sch = to_subchannel(dev);
	int ret;

	ret = add_uevent_var(env, "ST=%01X", sch->st);
	if (ret)
		return ret;
	ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
	return ret;
}

static struct bus_type css_bus_type = {
	.name     = "css",
	.match    = css_bus_match,
	.probe    = css_probe,
	.remove   = css_remove,
	.shutdown = css_shutdown,
	.uevent   = css_uevent,
};

/**
 * css_driver_register - register a css driver
 * @cdrv: css driver to register
 *
 * This is mainly a wrapper around driver_register that sets name
 * and bus_type in the embedded struct device_driver correctly.
 */
int css_driver_register(struct css_driver *cdrv)
{
	cdrv->drv.bus = &css_bus_type;
	return driver_register(&cdrv->drv);
}
EXPORT_SYMBOL_GPL(css_driver_register);

/**
 * css_driver_unregister - unregister a css driver
 * @cdrv: css driver to unregister
 *
 * This is a wrapper around driver_unregister.
 */
void css_driver_unregister(struct css_driver *cdrv)
{
	driver_unregister(&cdrv->drv);
}
EXPORT_SYMBOL_GPL(css_driver_unregister);