summaryrefslogtreecommitdiff
path: root/drivers/s390/cio/device.c
blob: dfef5e63cb7b925f39e6974d4a6ef438059d4894 (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
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
/*
 *  bus driver for ccw devices
 *
 *    Copyright IBM Corp. 2002, 2008
 *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
 *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

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

#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 <linux/delay.h>
#include <linux/timer.h>
#include <linux/kernel_stat.h>

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

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

static struct timer_list recovery_timer;
static DEFINE_SPINLOCK(recovery_lock);
static int recovery_phase;
static const unsigned long recovery_delay[] = { 3, 30, 300 };

static atomic_t ccw_device_init_count = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(ccw_device_init_wq);
static struct bus_type ccw_bus_type;

/******************* 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,
			 struct ccw_device_id *id, const char *suffix)
{
	int len;

	len = snprintf(buf, size, "ccw:t%04Xm%02X", 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, struct kobj_uevent_env *env)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);
	int ret;
	char modalias_buf[30];

	/* CU_TYPE= */
	ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
	if (ret)
		return ret;

	/* CU_MODEL= */
	ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
	if (ret)
		return ret;

	/* The next two can be zero, that's ok for us */
	/* DEV_TYPE= */
	ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
	if (ret)
		return ret;

	/* DEV_MODEL= */
	ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
	if (ret)
		return ret;

	/* MODALIAS=  */
	snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
	ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
	return ret;
}

static void io_subchannel_irq(struct subchannel *);
static int io_subchannel_probe(struct subchannel *);
static int io_subchannel_remove(struct subchannel *);
static void io_subchannel_shutdown(struct subchannel *);
static int io_subchannel_sch_event(struct subchannel *, int);
static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
				   int);
static void recovery_func(unsigned long data);

static struct css_device_id io_subchannel_ids[] = {
	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
	{ /* end of list */ },
};
MODULE_DEVICE_TABLE(css, io_subchannel_ids);

static int io_subchannel_prepare(struct subchannel *sch)
{
	struct ccw_device *cdev;
	/*
	 * Don't allow suspend while a ccw device registration
	 * is still outstanding.
	 */
	cdev = sch_get_cdev(sch);
	if (cdev && !device_is_registered(&cdev->dev))
		return -EAGAIN;
	return 0;
}

static int io_subchannel_settle(void)
{
	int ret;

	ret = wait_event_interruptible(ccw_device_init_wq,
				atomic_read(&ccw_device_init_count) == 0);
	if (ret)
		return -EINTR;
	flush_workqueue(cio_work_q);
	return 0;
}

static struct css_driver io_subchannel_driver = {
	.drv = {
		.owner = THIS_MODULE,
		.name = "io_subchannel",
	},
	.subchannel_type = io_subchannel_ids,
	.irq = io_subchannel_irq,
	.sch_event = io_subchannel_sch_event,
	.chp_event = io_subchannel_chp_event,
	.probe = io_subchannel_probe,
	.remove = io_subchannel_remove,
	.shutdown = io_subchannel_shutdown,
	.prepare = io_subchannel_prepare,
	.settle = io_subchannel_settle,
};

int __init io_subchannel_init(void)
{
	int ret;

	setup_timer(&recovery_timer, recovery_func, 0);
	ret = bus_register(&ccw_bus_type);
	if (ret)
		return ret;
	ret = css_driver_register(&io_subchannel_driver);
	if (ret)
		bus_unregister(&ccw_bus_type);

	return ret;
}


/************************ 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 chsc_ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int chp;
	int mask;

	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 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");

	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");
}

int ccw_device_is_orphan(struct ccw_device *cdev)
{
	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
}

static void ccw_device_unregister(struct ccw_device *cdev)
{
	if (device_is_registered(&cdev->dev)) {
		/* Undo device_add(). */
		device_del(&cdev->dev);
	}
	if (cdev->private->flags.initialized) {
		cdev->private->flags.initialized = 0;
		/* Release reference from device_initialize(). */
		put_device(&cdev->dev);
	}
}

static void io_subchannel_quiesce(struct subchannel *);

/**
 * ccw_device_set_offline() - disable a ccw device for I/O
 * @cdev: target ccw device
 *
 * This function calls the driver's set_offline() function for @cdev, if
 * given, and then disables @cdev.
 * Returns:
 *   %0 on success and a negative error value on failure.
 * Context:
 *  enabled, ccw device lock not held
 */
int ccw_device_set_offline(struct ccw_device *cdev)
{
	struct subchannel *sch;
	int ret, state;

	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;
	}
	spin_lock_irq(cdev->ccwlock);
	sch = to_subchannel(cdev->dev.parent);
	cdev->online = 0;
	/* Wait until a final state or DISCONNECTED is reached */
	while (!dev_fsm_final_state(cdev) &&
	       cdev->private->state != DEV_STATE_DISCONNECTED) {
		spin_unlock_irq(cdev->ccwlock);
		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
			   cdev->private->state == DEV_STATE_DISCONNECTED));
		spin_lock_irq(cdev->ccwlock);
	}
	do {
		ret = ccw_device_offline(cdev);
		if (!ret)
			break;
		CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device "
			      "0.%x.%04x\n", ret, cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
		if (ret != -EBUSY)
			goto error;
		state = cdev->private->state;
		spin_unlock_irq(cdev->ccwlock);
		io_subchannel_quiesce(sch);
		spin_lock_irq(cdev->ccwlock);
		cdev->private->state = state;
	} while (ret == -EBUSY);
	spin_unlock_irq(cdev->ccwlock);
	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
		   cdev->private->state == DEV_STATE_DISCONNECTED));
	/* Inform the user if set offline failed. */
	if (cdev->private->state == DEV_STATE_BOXED) {
		pr_warning("%s: The device entered boxed state while "
			   "being set offline\n", dev_name(&cdev->dev));
	} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
		pr_warning("%s: The device stopped operating while "
			   "being set offline\n", dev_name(&cdev->dev));
	}
	/* Give up reference from ccw_device_set_online(). */
	put_device(&cdev->dev);
	return 0;

error:
	cdev->private->state = DEV_STATE_OFFLINE;
	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
	spin_unlock_irq(cdev->ccwlock);
	/* Give up reference from ccw_device_set_online(). */
	put_device(&cdev->dev);
	return -ENODEV;
}

/**
 * ccw_device_set_online() - enable a ccw device for I/O
 * @cdev: target ccw device
 *
 * This function first enables @cdev and then calls the driver's set_online()
 * function for @cdev, if given. If set_online() returns an error, @cdev is
 * disabled again.
 * Returns:
 *   %0 on success and a negative error value on failure.
 * Context:
 *  enabled, ccw device lock not held
 */
int ccw_device_set_online(struct ccw_device *cdev)
{
	int ret;
	int ret2;

	if (!cdev)
		return -ENODEV;
	if (cdev->online || !cdev->drv)
		return -EINVAL;
	/* Hold on to an extra reference while device is online. */
	if (!get_device(&cdev->dev))
		return -ENODEV;

	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 {
		CIO_MSG_EVENT(0, "ccw_device_online returned %d, "
			      "device 0.%x.%04x\n",
			      ret, cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
		/* Give up online reference since onlining failed. */
		put_device(&cdev->dev);
		return ret;
	}
	spin_lock_irq(cdev->ccwlock);
	/* Check if online processing was successful */
	if ((cdev->private->state != DEV_STATE_ONLINE) &&
	    (cdev->private->state != DEV_STATE_W4SENSE)) {
		spin_unlock_irq(cdev->ccwlock);
		/* Inform the user that set online failed. */
		if (cdev->private->state == DEV_STATE_BOXED) {
			pr_warning("%s: Setting the device online failed "
				   "because it is boxed\n",
				   dev_name(&cdev->dev));
		} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
			pr_warning("%s: Setting the device online failed "
				   "because it is not operational\n",
				   dev_name(&cdev->dev));
		}
		/* Give up online reference since onlining failed. */
		put_device(&cdev->dev);
		return -ENODEV;
	}
	spin_unlock_irq(cdev->ccwlock);
	if (cdev->drv->set_online)
		ret = cdev->drv->set_online(cdev);
	if (ret)
		goto rollback;

	spin_lock_irq(cdev->ccwlock);
	cdev->online = 1;
	spin_unlock_irq(cdev->ccwlock);
	return 0;

rollback:
	spin_lock_irq(cdev->ccwlock);
	/* Wait until a final state or DISCONNECTED is reached */
	while (!dev_fsm_final_state(cdev) &&
	       cdev->private->state != DEV_STATE_DISCONNECTED) {
		spin_unlock_irq(cdev->ccwlock);
		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
			   cdev->private->state == DEV_STATE_DISCONNECTED));
		spin_lock_irq(cdev->ccwlock);
	}
	ret2 = ccw_device_offline(cdev);
	if (ret2)
		goto error;
	spin_unlock_irq(cdev->ccwlock);
	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
		   cdev->private->state == DEV_STATE_DISCONNECTED));
	/* Give up online reference since onlining failed. */
	put_device(&cdev->dev);
	return ret;

error:
	CIO_MSG_EVENT(0, "rollback ccw_device_offline returned %d, "
		      "device 0.%x.%04x\n",
		      ret2, cdev->private->dev_id.ssid,
		      cdev->private->dev_id.devno);
	cdev->private->state = DEV_STATE_OFFLINE;
	spin_unlock_irq(cdev->ccwlock);
	/* Give up online reference since onlining failed. */
	put_device(&cdev->dev);
	return ret;
}

static int online_store_handle_offline(struct ccw_device *cdev)
{
	if (cdev->private->state == DEV_STATE_DISCONNECTED) {
		spin_lock_irq(cdev->ccwlock);
		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
		spin_unlock_irq(cdev->ccwlock);
		return 0;
	}
	if (cdev->drv && cdev->drv->set_offline)
		return ccw_device_set_offline(cdev);
	return -EINVAL;
}

static int online_store_recog_and_online(struct ccw_device *cdev)
{
	/* Do device recognition, if needed. */
	if (cdev->private->state == DEV_STATE_BOXED) {
		spin_lock_irq(cdev->ccwlock);
		ccw_device_recognition(cdev);
		spin_unlock_irq(cdev->ccwlock);
		wait_event(cdev->private->wait_q,
			   cdev->private->flags.recog_done);
		if (cdev->private->state != DEV_STATE_OFFLINE)
			/* recognition failed */
			return -EAGAIN;
	}
	if (cdev->drv && cdev->drv->set_online)
		return ccw_device_set_online(cdev);
	return -EINVAL;
}

static int online_store_handle_online(struct ccw_device *cdev, int force)
{
	int ret;

	ret = online_store_recog_and_online(cdev);
	if (ret && !force)
		return ret;
	if (force && cdev->private->state == DEV_STATE_BOXED) {
		ret = ccw_device_stlck(cdev);
		if (ret)
			return ret;
		if (cdev->id.cu_type == 0)
			cdev->private->state = DEV_STATE_NOT_OPER;
		ret = online_store_recog_and_online(cdev);
		if (ret)
			return ret;
	}
	return 0;
}

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 force, ret;
	unsigned long i;

	/* Prevent conflict between multiple on-/offline processing requests. */
	if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
		return -EAGAIN;
	/* Prevent conflict between internal I/Os and on-/offline processing. */
	if (!dev_fsm_final_state(cdev) &&
	    cdev->private->state != DEV_STATE_DISCONNECTED) {
		ret = -EAGAIN;
		goto out;
	}
	/* Prevent conflict between pending work and on-/offline processing.*/
	if (work_pending(&cdev->private->todo_work)) {
		ret = -EAGAIN;
		goto out;
	}
	if (!strncmp(buf, "force\n", count)) {
		force = 1;
		i = 1;
		ret = 0;
	} else {
		force = 0;
		ret = kstrtoul(buf, 16, &i);
	}
	if (ret)
		goto out;

	device_lock(dev);
	switch (i) {
	case 0:
		ret = online_store_handle_offline(cdev);
		break;
	case 1:
		ret = online_store_handle_online(cdev, force);
		break;
	default:
		ret = -EINVAL;
	}
	device_unlock(dev);

out:
	atomic_set(&cdev->private->onoff, 0);
	return (ret < 0) ? ret : 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;

	if (ccw_device_is_orphan(cdev))
		return sprintf(buf, "no device\n");
	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 ssize_t
initiate_logging(struct device *dev, struct device_attribute *attr,
		 const char *buf, size_t count)
{
	struct subchannel *sch = to_subchannel(dev);
	int rc;

	rc = chsc_siosl(sch->schid);
	if (rc < 0) {
		pr_warning("Logging for subchannel 0.%x.%04x failed with "
			   "errno=%d\n",
			   sch->schid.ssid, sch->schid.sch_no, rc);
		return rc;
	}
	pr_notice("Logging for subchannel 0.%x.%04x was triggered\n",
		  sch->schid.ssid, sch->schid.sch_no);
	return count;
}

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

	return sprintf(buf, "%02x\n", sch->vpm);
}

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);
static DEVICE_ATTR(availability, 0444, available_show, NULL);
static DEVICE_ATTR(logging, 0200, NULL, initiate_logging);
static DEVICE_ATTR(vpm, 0444, vpm_show, NULL);

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

static struct attribute_group io_subchannel_attr_group = {
	.attrs = io_subchannel_attrs,
};

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 const struct attribute_group *ccwdev_attr_groups[] = {
	&ccwdev_attr_group,
	NULL,
};

static int ccw_device_add(struct ccw_device *cdev)
{
	struct device *dev = &cdev->dev;

	dev->bus = &ccw_bus_type;
	return device_add(dev);
}

static int match_dev_id(struct device *dev, void *data)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_dev_id *dev_id = data;

	return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
}

/**
 * get_ccwdev_by_dev_id() - obtain device from a ccw device id
 * @dev_id: id of the device to be searched
 *
 * This function searches all devices attached to the ccw bus for a device
 * matching @dev_id.
 * Returns:
 *  If a device is found its reference count is increased and returned;
 *  else %NULL is returned.
 */
struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
{
	struct device *dev;

	dev = bus_find_device(&ccw_bus_type, NULL, dev_id, match_dev_id);

	return dev ? to_ccwdev(dev) : NULL;
}
EXPORT_SYMBOL_GPL(get_ccwdev_by_dev_id);

static void ccw_device_do_unbind_bind(struct ccw_device *cdev)
{
	int ret;

	if (device_is_registered(&cdev->dev)) {
		device_release_driver(&cdev->dev);
		ret = device_attach(&cdev->dev);
		WARN_ON(ret == -ENODEV);
	}
}

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

	cdev = to_ccwdev(dev);
	/* Release reference of parent subchannel. */
	put_device(cdev->dev.parent);
	kfree(cdev->private);
	kfree(cdev);
}

static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
{
	struct ccw_device *cdev;

	cdev  = kzalloc(sizeof(*cdev), GFP_KERNEL);
	if (cdev) {
		cdev->private = kzalloc(sizeof(struct ccw_device_private),
					GFP_KERNEL | GFP_DMA);
		if (cdev->private)
			return cdev;
	}
	kfree(cdev);
	return ERR_PTR(-ENOMEM);
}

static void ccw_device_todo(struct work_struct *work);

static int io_subchannel_initialize_dev(struct subchannel *sch,
					struct ccw_device *cdev)
{
	struct ccw_device_private *priv = cdev->private;
	int ret;

	priv->cdev = cdev;
	priv->int_class = IRQIO_CIO;
	priv->state = DEV_STATE_NOT_OPER;
	priv->dev_id.devno = sch->schib.pmcw.dev;
	priv->dev_id.ssid = sch->schid.ssid;
	priv->schid = sch->schid;

	INIT_WORK(&priv->todo_work, ccw_device_todo);
	INIT_LIST_HEAD(&priv->cmb_list);
	init_waitqueue_head(&priv->wait_q);
	init_timer(&priv->timer);

	atomic_set(&priv->onoff, 0);
	cdev->ccwlock = sch->lock;
	cdev->dev.parent = &sch->dev;
	cdev->dev.release = ccw_device_release;
	cdev->dev.groups = ccwdev_attr_groups;
	/* Do first half of device_register. */
	device_initialize(&cdev->dev);
	ret = dev_set_name(&cdev->dev, "0.%x.%04x", cdev->private->dev_id.ssid,
			   cdev->private->dev_id.devno);
	if (ret)
		goto out_put;
	if (!get_device(&sch->dev)) {
		ret = -ENODEV;
		goto out_put;
	}
	priv->flags.initialized = 1;
	spin_lock_irq(sch->lock);
	sch_set_cdev(sch, cdev);
	spin_unlock_irq(sch->lock);
	return 0;

out_put:
	/* Release reference from device_initialize(). */
	put_device(&cdev->dev);
	return ret;
}

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

	cdev = io_subchannel_allocate_dev(sch);
	if (!IS_ERR(cdev)) {
		ret = io_subchannel_initialize_dev(sch, cdev);
		if (ret)
			cdev = ERR_PTR(ret);
	}
	return cdev;
}

static void io_subchannel_recog(struct ccw_device *, struct subchannel *);

static void sch_create_and_recog_new_device(struct subchannel *sch)
{
	struct ccw_device *cdev;

	/* Need to allocate a new ccw device. */
	cdev = io_subchannel_create_ccwdev(sch);
	if (IS_ERR(cdev)) {
		/* OK, we did everything we could... */
		css_sch_device_unregister(sch);
		return;
	}
	/* Start recognition for the new ccw device. */
	io_subchannel_recog(cdev, sch);
}

/*
 * Register recognized device.
 */
static void io_subchannel_register(struct ccw_device *cdev)
{
	struct subchannel *sch;
	int ret, adjust_init_count = 1;
	unsigned long flags;

	sch = to_subchannel(cdev->dev.parent);
	/*
	 * Check if subchannel is still registered. It may have become
	 * unregistered if a machine check hit us after finishing
	 * device recognition but before the register work could be
	 * queued.
	 */
	if (!device_is_registered(&sch->dev))
		goto out_err;
	css_update_ssd_info(sch);
	/*
	 * io_subchannel_register() will also be called after device
	 * recognition has been done for a boxed device (which will already
	 * be registered). We need to reprobe since we may now have sense id
	 * information.
	 */
	if (device_is_registered(&cdev->dev)) {
		if (!cdev->drv) {
			ret = device_reprobe(&cdev->dev);
			if (ret)
				/* We can't do much here. */
				CIO_MSG_EVENT(0, "device_reprobe() returned"
					      " %d for 0.%x.%04x\n", ret,
					      cdev->private->dev_id.ssid,
					      cdev->private->dev_id.devno);
		}
		adjust_init_count = 0;
		goto out;
	}
	/*
	 * Now we know this subchannel will stay, we can throw
	 * our delayed uevent.
	 */
	dev_set_uevent_suppress(&sch->dev, 0);
	kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
	/* make it known to the system */
	ret = ccw_device_add(cdev);
	if (ret) {
		CIO_MSG_EVENT(0, "Could not register ccw dev 0.%x.%04x: %d\n",
			      cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno, ret);
		spin_lock_irqsave(sch->lock, flags);
		sch_set_cdev(sch, NULL);
		spin_unlock_irqrestore(sch->lock, flags);
		/* Release initial device reference. */
		put_device(&cdev->dev);
		goto out_err;
	}
out:
	cdev->private->flags.recog_done = 1;
	wake_up(&cdev->private->wait_q);
out_err:
	if (adjust_init_count && atomic_dec_and_test(&ccw_device_init_count))
		wake_up(&ccw_device_init_wq);
}

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

	/* Get subchannel reference for local processing. */
	if (!get_device(cdev->dev.parent))
		return;
	sch = to_subchannel(cdev->dev.parent);
	css_sch_device_unregister(sch);
	/* Release subchannel reference for local processing. */
	put_device(&sch->dev);
}

/*
 * subchannel recognition done. Called from the state machine.
 */
void
io_subchannel_recog_done(struct ccw_device *cdev)
{
	if (css_init_done == 0) {
		cdev->private->flags.recog_done = 1;
		return;
	}
	switch (cdev->private->state) {
	case DEV_STATE_BOXED:
		/* Device did not respond in time. */
	case DEV_STATE_NOT_OPER:
		cdev->private->flags.recog_done = 1;
		/* Remove device found not operational. */
		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
		break;
	case DEV_STATE_OFFLINE:
		/* 
		 * We can't register the device in interrupt context so
		 * we schedule a work item.
		 */
		ccw_device_sched_todo(cdev, CDEV_TODO_REGISTER);
		break;
	}
}

static void io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
{
	/* Increase counter of devices currently in recognition. */
	atomic_inc(&ccw_device_init_count);

	/* Start async. device sensing. */
	spin_lock_irq(sch->lock);
	ccw_device_recognition(cdev);
	spin_unlock_irq(sch->lock);
}

static int ccw_device_move_to_sch(struct ccw_device *cdev,
				  struct subchannel *sch)
{
	struct subchannel *old_sch;
	int rc, old_enabled = 0;

	old_sch = to_subchannel(cdev->dev.parent);
	/* Obtain child reference for new parent. */
	if (!get_device(&sch->dev))
		return -ENODEV;

	if (!sch_is_pseudo_sch(old_sch)) {
		spin_lock_irq(old_sch->lock);
		old_enabled = old_sch->schib.pmcw.ena;
		rc = 0;
		if (old_enabled)
			rc = cio_disable_subchannel(old_sch);
		spin_unlock_irq(old_sch->lock);
		if (rc == -EBUSY) {
			/* Release child reference for new parent. */
			put_device(&sch->dev);
			return rc;
		}
	}

	mutex_lock(&sch->reg_mutex);
	rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
	mutex_unlock(&sch->reg_mutex);
	if (rc) {
		CIO_MSG_EVENT(0, "device_move(0.%x.%04x,0.%x.%04x)=%d\n",
			      cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno, sch->schid.ssid,
			      sch->schib.pmcw.dev, rc);
		if (old_enabled) {
			/* Try to reenable the old subchannel. */
			spin_lock_irq(old_sch->lock);
			cio_enable_subchannel(old_sch, (u32)(addr_t)old_sch);
			spin_unlock_irq(old_sch->lock);
		}
		/* Release child reference for new parent. */
		put_device(&sch->dev);
		return rc;
	}
	/* Clean up old subchannel. */
	if (!sch_is_pseudo_sch(old_sch)) {
		spin_lock_irq(old_sch->lock);
		sch_set_cdev(old_sch, NULL);
		spin_unlock_irq(old_sch->lock);
		css_schedule_eval(old_sch->schid);
	}
	/* Release child reference for old parent. */
	put_device(&old_sch->dev);
	/* Initialize new subchannel. */
	spin_lock_irq(sch->lock);
	cdev->private->schid = sch->schid;
	cdev->ccwlock = sch->lock;
	if (!sch_is_pseudo_sch(sch))
		sch_set_cdev(sch, cdev);
	spin_unlock_irq(sch->lock);
	if (!sch_is_pseudo_sch(sch))
		css_update_ssd_info(sch);
	return 0;
}

static int ccw_device_move_to_orph(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct channel_subsystem *css = to_css(sch->dev.parent);

	return ccw_device_move_to_sch(cdev, css->pseudo_subchannel);
}

static void io_subchannel_irq(struct subchannel *sch)
{
	struct ccw_device *cdev;

	cdev = sch_get_cdev(sch);

	CIO_TRACE_EVENT(6, "IRQ");
	CIO_TRACE_EVENT(6, dev_name(&sch->dev));
	if (cdev)
		dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
	else
		inc_irq_stat(IRQIO_CIO);
}

void io_subchannel_init_config(struct subchannel *sch)
{
	memset(&sch->config, 0, sizeof(sch->config));
	sch->config.csense = 1;
}

static void io_subchannel_init_fields(struct subchannel *sch)
{
	if (cio_is_console(sch->schid))
		sch->opm = 0xff;
	else
		sch->opm = chp_get_sch_opm(sch);
	sch->lpm = sch->schib.pmcw.pam & sch->opm;
	sch->isc = cio_is_console(sch->schid) ? CONSOLE_ISC : IO_SCH_ISC;

	CIO_MSG_EVENT(6, "Detected device %04x on subchannel 0.%x.%04X"
		      " - PIM = %02X, PAM = %02X, POM = %02X\n",
		      sch->schib.pmcw.dev, sch->schid.ssid,
		      sch->schid.sch_no, sch->schib.pmcw.pim,
		      sch->schib.pmcw.pam, sch->schib.pmcw.pom);

	io_subchannel_init_config(sch);
}

/*
 * Note: We always return 0 so that we bind to the device even on error.
 * This is needed so that our remove function is called on unregister.
 */
static int io_subchannel_probe(struct subchannel *sch)
{
	struct io_subchannel_private *io_priv;
	struct ccw_device *cdev;
	int rc;

	if (cio_is_console(sch->schid)) {
		rc = sysfs_create_group(&sch->dev.kobj,
					&io_subchannel_attr_group);
		if (rc)
			CIO_MSG_EVENT(0, "Failed to create io subchannel "
				      "attributes for subchannel "
				      "0.%x.%04x (rc=%d)\n",
				      sch->schid.ssid, sch->schid.sch_no, rc);
		/*
		 * The console subchannel already has an associated ccw_device.
		 * Throw the delayed uevent for the subchannel, register
		 * the ccw_device and exit.
		 */
		dev_set_uevent_suppress(&sch->dev, 0);
		kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
		cdev = sch_get_cdev(sch);
		rc = ccw_device_add(cdev);
		if (rc) {
			/* Release online reference. */
			put_device(&cdev->dev);
			goto out_schedule;
		}
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
		return 0;
	}
	io_subchannel_init_fields(sch);
	rc = cio_commit_config(sch);
	if (rc)
		goto out_schedule;
	rc = sysfs_create_group(&sch->dev.kobj,
				&io_subchannel_attr_group);
	if (rc)
		goto out_schedule;
	/* Allocate I/O subchannel private data. */
	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
	if (!io_priv)
		goto out_schedule;

	set_io_private(sch, io_priv);
	css_schedule_eval(sch->schid);
	return 0;

out_schedule:
	spin_lock_irq(sch->lock);
	css_sched_sch_todo(sch, SCH_TODO_UNREG);
	spin_unlock_irq(sch->lock);
	return 0;
}

static int
io_subchannel_remove (struct subchannel *sch)
{
	struct io_subchannel_private *io_priv = to_io_private(sch);
	struct ccw_device *cdev;

	cdev = sch_get_cdev(sch);
	if (!cdev)
		goto out_free;
	io_subchannel_quiesce(sch);
	/* Set ccw device to not operational and drop reference. */
	spin_lock_irq(cdev->ccwlock);
	sch_set_cdev(sch, NULL);
	set_io_private(sch, NULL);
	cdev->private->state = DEV_STATE_NOT_OPER;
	spin_unlock_irq(cdev->ccwlock);
	ccw_device_unregister(cdev);
out_free:
	kfree(io_priv);
	sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
	return 0;
}

static void io_subchannel_verify(struct subchannel *sch)
{
	struct ccw_device *cdev;

	cdev = sch_get_cdev(sch);
	if (cdev)
		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
}

static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
{
	struct ccw_device *cdev;

	cdev = sch_get_cdev(sch);
	if (!cdev)
		return;
	if (cio_update_schib(sch))
		goto err;
	/* Check for I/O on path. */
	if (scsw_actl(&sch->schib.scsw) == 0 || sch->schib.pmcw.lpum != mask)
		goto out;
	if (cdev->private->state == DEV_STATE_ONLINE) {
		ccw_device_kill_io(cdev);
		goto out;
	}
	if (cio_clear(sch))
		goto err;
out:
	/* Trigger path verification. */
	dev_fsm_event(cdev, DEV_EVENT_VERIFY);
	return;

err:
	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
}

static int io_subchannel_chp_event(struct subchannel *sch,
				   struct chp_link *link, int event)
{
	struct ccw_device *cdev = sch_get_cdev(sch);
	int mask;

	mask = chp_ssd_get_mask(&sch->ssd_info, link);
	if (!mask)
		return 0;
	switch (event) {
	case CHP_VARY_OFF:
		sch->opm &= ~mask;
		sch->lpm &= ~mask;
		if (cdev)
			cdev->private->path_gone_mask |= mask;
		io_subchannel_terminate_path(sch, mask);
		break;
	case CHP_VARY_ON:
		sch->opm |= mask;
		sch->lpm |= mask;
		if (cdev)
			cdev->private->path_new_mask |= mask;
		io_subchannel_verify(sch);
		break;
	case CHP_OFFLINE:
		if (cio_update_schib(sch))
			return -ENODEV;
		if (cdev)
			cdev->private->path_gone_mask |= mask;
		io_subchannel_terminate_path(sch, mask);
		break;
	case CHP_ONLINE:
		if (cio_update_schib(sch))
			return -ENODEV;
		sch->lpm |= mask & sch->opm;
		if (cdev)
			cdev->private->path_new_mask |= mask;
		io_subchannel_verify(sch);
		break;
	}
	return 0;
}

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

	spin_lock_irq(sch->lock);
	cdev = sch_get_cdev(sch);
	if (cio_is_console(sch->schid))
		goto out_unlock;
	if (!sch->schib.pmcw.ena)
		goto out_unlock;
	ret = cio_disable_subchannel(sch);
	if (ret != -EBUSY)
		goto out_unlock;
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));
	while (ret == -EBUSY) {
		cdev->private->state = DEV_STATE_QUIESCE;
		cdev->private->iretry = 255;
		ret = ccw_device_cancel_halt_clear(cdev);
		if (ret == -EBUSY) {
			ccw_device_set_timeout(cdev, HZ/10);
			spin_unlock_irq(sch->lock);
			wait_event(cdev->private->wait_q,
				   cdev->private->state != DEV_STATE_QUIESCE);
			spin_lock_irq(sch->lock);
		}
		ret = cio_disable_subchannel(sch);
	}
out_unlock:
	spin_unlock_irq(sch->lock);
}

static void io_subchannel_shutdown(struct subchannel *sch)
{
	io_subchannel_quiesce(sch);
}

static int device_is_disconnected(struct ccw_device *cdev)
{
	if (!cdev)
		return 0;
	return (cdev->private->state == DEV_STATE_DISCONNECTED ||
		cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
}

static int recovery_check(struct device *dev, void *data)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	int *redo = data;

	spin_lock_irq(cdev->ccwlock);
	switch (cdev->private->state) {
	case DEV_STATE_DISCONNECTED:
		CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
			      cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
		*redo = 1;
		break;
	case DEV_STATE_DISCONNECTED_SENSE_ID:
		*redo = 1;
		break;
	}
	spin_unlock_irq(cdev->ccwlock);

	return 0;
}

static void recovery_work_func(struct work_struct *unused)
{
	int redo = 0;

	bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
	if (redo) {
		spin_lock_irq(&recovery_lock);
		if (!timer_pending(&recovery_timer)) {
			if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
				recovery_phase++;
			mod_timer(&recovery_timer, jiffies +
				  recovery_delay[recovery_phase] * HZ);
		}
		spin_unlock_irq(&recovery_lock);
	} else
		CIO_MSG_EVENT(4, "recovery: end\n");
}

static DECLARE_WORK(recovery_work, recovery_work_func);

static void recovery_func(unsigned long data)
{
	/*
	 * We can't do our recovery in softirq context and it's not
	 * performance critical, so we schedule it.
	 */
	schedule_work(&recovery_work);
}

static void ccw_device_schedule_recovery(void)
{
	unsigned long flags;

	CIO_MSG_EVENT(4, "recovery: schedule\n");
	spin_lock_irqsave(&recovery_lock, flags);
	if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
		recovery_phase = 0;
		mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
	}
	spin_unlock_irqrestore(&recovery_lock, flags);
}

static int purge_fn(struct device *dev, void *data)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_dev_id *id = &cdev->private->dev_id;

	spin_lock_irq(cdev->ccwlock);
	if (is_blacklisted(id->ssid, id->devno) &&
	    (cdev->private->state == DEV_STATE_OFFLINE) &&
	    (atomic_cmpxchg(&cdev->private->onoff, 0, 1) == 0)) {
		CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid,
			      id->devno);
		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
		atomic_set(&cdev->private->onoff, 0);
	}
	spin_unlock_irq(cdev->ccwlock);
	/* Abort loop in case of pending signal. */
	if (signal_pending(current))
		return -EINTR;

	return 0;
}

/**
 * ccw_purge_blacklisted - purge unused, blacklisted devices
 *
 * Unregister all ccw devices that are offline and on the blacklist.
 */
int ccw_purge_blacklisted(void)
{
	CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
	bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn);
	return 0;
}

void ccw_device_set_disconnected(struct ccw_device *cdev)
{
	if (!cdev)
		return;
	ccw_device_set_timeout(cdev, 0);
	cdev->private->flags.fake_irb = 0;
	cdev->private->state = DEV_STATE_DISCONNECTED;
	if (cdev->online)
		ccw_device_schedule_recovery();
}

void ccw_device_set_notoper(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	CIO_TRACE_EVENT(2, "notoper");
	CIO_TRACE_EVENT(2, dev_name(&sch->dev));
	ccw_device_set_timeout(cdev, 0);
	cio_disable_subchannel(sch);
	cdev->private->state = DEV_STATE_NOT_OPER;
}

enum io_sch_action {
	IO_SCH_UNREG,
	IO_SCH_ORPH_UNREG,
	IO_SCH_ATTACH,
	IO_SCH_UNREG_ATTACH,
	IO_SCH_ORPH_ATTACH,
	IO_SCH_REPROBE,
	IO_SCH_VERIFY,
	IO_SCH_DISC,
	IO_SCH_NOP,
};

static enum io_sch_action sch_get_action(struct subchannel *sch)
{
	struct ccw_device *cdev;

	cdev = sch_get_cdev(sch);
	if (cio_update_schib(sch)) {
		/* Not operational. */
		if (!cdev)
			return IO_SCH_UNREG;
		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
			return IO_SCH_UNREG;
		return IO_SCH_ORPH_UNREG;
	}
	/* Operational. */
	if (!cdev)
		return IO_SCH_ATTACH;
	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
			return IO_SCH_UNREG_ATTACH;
		return IO_SCH_ORPH_ATTACH;
	}
	if ((sch->schib.pmcw.pam & sch->opm) == 0) {
		if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
			return IO_SCH_UNREG;
		return IO_SCH_DISC;
	}
	if (device_is_disconnected(cdev))
		return IO_SCH_REPROBE;
	if (cdev->online && !cdev->private->flags.resuming)
		return IO_SCH_VERIFY;
	if (cdev->private->state == DEV_STATE_NOT_OPER)
		return IO_SCH_UNREG_ATTACH;
	return IO_SCH_NOP;
}

/**
 * io_subchannel_sch_event - process subchannel event
 * @sch: subchannel
 * @process: non-zero if function is called in process context
 *
 * An unspecified event occurred for this subchannel. Adjust data according
 * to the current operational state of the subchannel and device. Return
 * zero when the event has been handled sufficiently or -EAGAIN when this
 * function should be called again in process context.
 */
static int io_subchannel_sch_event(struct subchannel *sch, int process)
{
	unsigned long flags;
	struct ccw_device *cdev;
	struct ccw_dev_id dev_id;
	enum io_sch_action action;
	int rc = -EAGAIN;

	spin_lock_irqsave(sch->lock, flags);
	if (!device_is_registered(&sch->dev))
		goto out_unlock;
	if (work_pending(&sch->todo_work))
		goto out_unlock;
	cdev = sch_get_cdev(sch);
	if (cdev && work_pending(&cdev->private->todo_work))
		goto out_unlock;
	action = sch_get_action(sch);
	CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
		      sch->schid.ssid, sch->schid.sch_no, process,
		      action);
	/* Perform immediate actions while holding the lock. */
	switch (action) {
	case IO_SCH_REPROBE:
		/* Trigger device recognition. */
		ccw_device_trigger_reprobe(cdev);
		rc = 0;
		goto out_unlock;
	case IO_SCH_VERIFY:
		/* Trigger path verification. */
		io_subchannel_verify(sch);
		rc = 0;
		goto out_unlock;
	case IO_SCH_DISC:
		ccw_device_set_disconnected(cdev);
		rc = 0;
		goto out_unlock;
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_ORPH_ATTACH:
		ccw_device_set_disconnected(cdev);
		break;
	case IO_SCH_UNREG_ATTACH:
	case IO_SCH_UNREG:
		if (!cdev)
			break;
		if (cdev->private->state == DEV_STATE_SENSE_ID) {
			/*
			 * Note: delayed work triggered by this event
			 * and repeated calls to sch_event are synchronized
			 * by the above check for work_pending(cdev).
			 */
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
		} else
			ccw_device_set_notoper(cdev);
		break;
	case IO_SCH_NOP:
		rc = 0;
		goto out_unlock;
	default:
		break;
	}
	spin_unlock_irqrestore(sch->lock, flags);
	/* All other actions require process context. */
	if (!process)
		goto out;
	/* Handle attached ccw device. */
	switch (action) {
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_ORPH_ATTACH:
		/* Move ccw device to orphanage. */
		rc = ccw_device_move_to_orph(cdev);
		if (rc)
			goto out;
		break;
	case IO_SCH_UNREG_ATTACH:
		spin_lock_irqsave(sch->lock, flags);
		if (cdev->private->flags.resuming) {
			/* Device will be handled later. */
			rc = 0;
			goto out_unlock;
		}
		sch_set_cdev(sch, NULL);
		spin_unlock_irqrestore(sch->lock, flags);
		/* Unregister ccw device. */
		ccw_device_unregister(cdev);
		break;
	default:
		break;
	}
	/* Handle subchannel. */
	switch (action) {
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_UNREG:
		if (!cdev || !cdev->private->flags.resuming)
			css_sch_device_unregister(sch);
		break;
	case IO_SCH_ORPH_ATTACH:
	case IO_SCH_UNREG_ATTACH:
	case IO_SCH_ATTACH:
		dev_id.ssid = sch->schid.ssid;
		dev_id.devno = sch->schib.pmcw.dev;
		cdev = get_ccwdev_by_dev_id(&dev_id);
		if (!cdev) {
			sch_create_and_recog_new_device(sch);
			break;
		}
		rc = ccw_device_move_to_sch(cdev, sch);
		if (rc) {
			/* Release reference from get_ccwdev_by_dev_id() */
			put_device(&cdev->dev);
			goto out;
		}
		spin_lock_irqsave(sch->lock, flags);
		ccw_device_trigger_reprobe(cdev);
		spin_unlock_irqrestore(sch->lock, flags);
		/* Release reference from get_ccwdev_by_dev_id() */
		put_device(&cdev->dev);
		break;
	default:
		break;
	}
	return 0;

out_unlock:
	spin_unlock_irqrestore(sch->lock, flags);
out:
	return rc;
}

static void ccw_device_set_int_class(struct ccw_device *cdev)
{
	struct ccw_driver *cdrv = cdev->drv;

	/* Note: we interpret class 0 in this context as an uninitialized
	 * field since it translates to a non-I/O interrupt class. */
	if (cdrv->int_class != 0)
		cdev->private->int_class = cdrv->int_class;
	else
		cdev->private->int_class = IRQIO_CIO;
}

#ifdef CONFIG_CCW_CONSOLE
int __init ccw_device_enable_console(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	int rc;

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

	io_subchannel_init_fields(sch);
	rc = cio_commit_config(sch);
	if (rc)
		return rc;
	sch->driver = &io_subchannel_driver;
	io_subchannel_recog(cdev, sch);
	/* Now wait for the async. recognition to come to an end. */
	spin_lock_irq(cdev->ccwlock);
	while (!dev_fsm_final_state(cdev))
		ccw_device_wait_idle(cdev);

	/* Hold on to an extra reference while device is online. */
	get_device(&cdev->dev);
	rc = ccw_device_online(cdev);
	if (rc)
		goto out_unlock;

	while (!dev_fsm_final_state(cdev))
		ccw_device_wait_idle(cdev);

	if (cdev->private->state == DEV_STATE_ONLINE)
		cdev->online = 1;
	else
		rc = -EIO;
out_unlock:
	spin_unlock_irq(cdev->ccwlock);
	if (rc) /* Give up online reference since onlining failed. */
		put_device(&cdev->dev);
	return rc;
}

struct ccw_device * __init ccw_device_create_console(struct ccw_driver *drv)
{
	struct io_subchannel_private *io_priv;
	struct ccw_device *cdev;
	struct subchannel *sch;

	sch = cio_probe_console();
	if (IS_ERR(sch))
		return ERR_CAST(sch);

	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
	if (!io_priv) {
		put_device(&sch->dev);
		return ERR_PTR(-ENOMEM);
	}
	set_io_private(sch, io_priv);
	cdev = io_subchannel_create_ccwdev(sch);
	if (IS_ERR(cdev)) {
		put_device(&sch->dev);
		kfree(io_priv);
		return cdev;
	}
	cdev->drv = drv;
	ccw_device_set_int_class(cdev);
	return cdev;
}

void __init ccw_device_destroy_console(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct io_subchannel_private *io_priv = to_io_private(sch);

	set_io_private(sch, NULL);
	put_device(&sch->dev);
	put_device(&cdev->dev);
	kfree(io_priv);
}

/**
 * ccw_device_wait_idle() - busy wait for device to become idle
 * @cdev: ccw device
 *
 * Poll until activity control is zero, that is, no function or data
 * transfer is pending/active.
 * Called with device lock being held.
 */
void ccw_device_wait_idle(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	while (1) {
		cio_tsch(sch);
		if (sch->schib.scsw.cmd.actl == 0)
			break;
		udelay_simple(100);
	}
}

static int ccw_device_pm_restore(struct device *dev);

int ccw_device_force_console(struct ccw_device *cdev)
{
	return ccw_device_pm_restore(&cdev->dev);
}
EXPORT_SYMBOL_GPL(ccw_device_force_console);
#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 = id;

	return (strcmp(bus_id, dev_name(dev)) == 0);
}


/**
 * get_ccwdev_by_busid() - obtain device from a bus id
 * @cdrv: driver the device is owned by
 * @bus_id: bus id of the device to be searched
 *
 * This function searches all devices owned by @cdrv for a device with a bus
 * id matching @bus_id.
 * Returns:
 *  If a match is found, its reference count of the found device is increased
 *  and it is returned; else %NULL is returned.
 */
struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
				       const char *bus_id)
{
	struct device *dev;

	dev = driver_find_device(&cdrv->driver, NULL, (void *)bus_id,
				 __ccwdev_check_busid);

	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 */
	ccw_device_set_int_class(cdev);
	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
	if (ret) {
		cdev->drv = NULL;
		cdev->private->int_class = IRQIO_CIO;
		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;

	if (cdrv->remove)
		cdrv->remove(cdev);

	spin_lock_irq(cdev->ccwlock);
	if (cdev->online) {
		cdev->online = 0;
		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
			CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
				      "device 0.%x.%04x\n",
				      ret, cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno);
		/* Give up reference obtained in ccw_device_set_online(). */
		put_device(&cdev->dev);
		spin_lock_irq(cdev->ccwlock);
	}
	ccw_device_set_timeout(cdev, 0);
	cdev->drv = NULL;
	cdev->private->int_class = IRQIO_CIO;
	spin_unlock_irq(cdev->ccwlock);
	return 0;
}

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

	cdev = to_ccwdev(dev);
	if (cdev->drv && cdev->drv->shutdown)
		cdev->drv->shutdown(cdev);
	disable_cmf(cdev);
}

static int ccw_device_pm_prepare(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);

	if (work_pending(&cdev->private->todo_work))
		return -EAGAIN;
	/* Fail while device is being set online/offline. */
	if (atomic_read(&cdev->private->onoff))
		return -EAGAIN;

	if (cdev->online && cdev->drv && cdev->drv->prepare)
		return cdev->drv->prepare(cdev);

	return 0;
}

static void ccw_device_pm_complete(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);

	if (cdev->online && cdev->drv && cdev->drv->complete)
		cdev->drv->complete(cdev);
}

static int ccw_device_pm_freeze(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	int ret, cm_enabled;

	/* Fail suspend while device is in transistional state. */
	if (!dev_fsm_final_state(cdev))
		return -EAGAIN;
	if (!cdev->online)
		return 0;
	if (cdev->drv && cdev->drv->freeze) {
		ret = cdev->drv->freeze(cdev);
		if (ret)
			return ret;
	}

	spin_lock_irq(sch->lock);
	cm_enabled = cdev->private->cmb != NULL;
	spin_unlock_irq(sch->lock);
	if (cm_enabled) {
		/* Don't have the css write on memory. */
		ret = ccw_set_cmf(cdev, 0);
		if (ret)
			return ret;
	}
	/* From here on, disallow device driver I/O. */
	spin_lock_irq(sch->lock);
	ret = cio_disable_subchannel(sch);
	spin_unlock_irq(sch->lock);

	return ret;
}

static int ccw_device_pm_thaw(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	int ret, cm_enabled;

	if (!cdev->online)
		return 0;

	spin_lock_irq(sch->lock);
	/* Allow device driver I/O again. */
	ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
	cm_enabled = cdev->private->cmb != NULL;
	spin_unlock_irq(sch->lock);
	if (ret)
		return ret;

	if (cm_enabled) {
		ret = ccw_set_cmf(cdev, 1);
		if (ret)
			return ret;
	}

	if (cdev->drv && cdev->drv->thaw)
		ret = cdev->drv->thaw(cdev);

	return ret;
}

static void __ccw_device_pm_restore(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	spin_lock_irq(sch->lock);
	if (cio_is_console(sch->schid)) {
		cio_enable_subchannel(sch, (u32)(addr_t)sch);
		goto out_unlock;
	}
	/*
	 * While we were sleeping, devices may have gone or become
	 * available again. Kick re-detection.
	 */
	cdev->private->flags.resuming = 1;
	cdev->private->path_new_mask = LPM_ANYPATH;
	css_sched_sch_todo(sch, SCH_TODO_EVAL);
	spin_unlock_irq(sch->lock);
	css_wait_for_slow_path();

	/* cdev may have been moved to a different subchannel. */
	sch = to_subchannel(cdev->dev.parent);
	spin_lock_irq(sch->lock);
	if (cdev->private->state != DEV_STATE_ONLINE &&
	    cdev->private->state != DEV_STATE_OFFLINE)
		goto out_unlock;

	ccw_device_recognition(cdev);
	spin_unlock_irq(sch->lock);
	wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev) ||
		   cdev->private->state == DEV_STATE_DISCONNECTED);
	spin_lock_irq(sch->lock);

out_unlock:
	cdev->private->flags.resuming = 0;
	spin_unlock_irq(sch->lock);
}

static int resume_handle_boxed(struct ccw_device *cdev)
{
	cdev->private->state = DEV_STATE_BOXED;
	if (ccw_device_notify(cdev, CIO_BOXED) == NOTIFY_OK)
		return 0;
	ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
	return -ENODEV;
}

static int resume_handle_disc(struct ccw_device *cdev)
{
	cdev->private->state = DEV_STATE_DISCONNECTED;
	if (ccw_device_notify(cdev, CIO_GONE) == NOTIFY_OK)
		return 0;
	ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
	return -ENODEV;
}

static int ccw_device_pm_restore(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct subchannel *sch;
	int ret = 0;

	__ccw_device_pm_restore(cdev);
	sch = to_subchannel(cdev->dev.parent);
	spin_lock_irq(sch->lock);
	if (cio_is_console(sch->schid))
		goto out_restore;

	/* check recognition results */
	switch (cdev->private->state) {
	case DEV_STATE_OFFLINE:
	case DEV_STATE_ONLINE:
		cdev->private->flags.donotify = 0;
		break;
	case DEV_STATE_BOXED:
		ret = resume_handle_boxed(cdev);
		if (ret)
			goto out_unlock;
		goto out_restore;
	default:
		ret = resume_handle_disc(cdev);
		if (ret)
			goto out_unlock;
		goto out_restore;
	}
	/* check if the device type has changed */
	if (!ccw_device_test_sense_data(cdev)) {
		ccw_device_update_sense_data(cdev);
		ccw_device_sched_todo(cdev, CDEV_TODO_REBIND);
		ret = -ENODEV;
		goto out_unlock;
	}
	if (!cdev->online)
		goto out_unlock;

	if (ccw_device_online(cdev)) {
		ret = resume_handle_disc(cdev);
		if (ret)
			goto out_unlock;
		goto out_restore;
	}
	spin_unlock_irq(sch->lock);
	wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	spin_lock_irq(sch->lock);

	if (ccw_device_notify(cdev, CIO_OPER) == NOTIFY_BAD) {
		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
		ret = -ENODEV;
		goto out_unlock;
	}

	/* reenable cmf, if needed */
	if (cdev->private->cmb) {
		spin_unlock_irq(sch->lock);
		ret = ccw_set_cmf(cdev, 1);
		spin_lock_irq(sch->lock);
		if (ret) {
			CIO_MSG_EVENT(2, "resume: cdev 0.%x.%04x: cmf failed "
				      "(rc=%d)\n", cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno, ret);
			ret = 0;
		}
	}

out_restore:
	spin_unlock_irq(sch->lock);
	if (cdev->online && cdev->drv && cdev->drv->restore)
		ret = cdev->drv->restore(cdev);
	return ret;

out_unlock:
	spin_unlock_irq(sch->lock);
	return ret;
}

static const struct dev_pm_ops ccw_pm_ops = {
	.prepare = ccw_device_pm_prepare,
	.complete = ccw_device_pm_complete,
	.freeze = ccw_device_pm_freeze,
	.thaw = ccw_device_pm_thaw,
	.restore = ccw_device_pm_restore,
};

static struct bus_type ccw_bus_type = {
	.name   = "ccw",
	.match  = ccw_bus_match,
	.uevent = ccw_uevent,
	.probe  = ccw_device_probe,
	.remove = ccw_device_remove,
	.shutdown = ccw_device_shutdown,
	.pm = &ccw_pm_ops,
};

/**
 * ccw_driver_register() - register a ccw driver
 * @cdriver: driver to be registered
 *
 * This function is mainly a wrapper around driver_register().
 * Returns:
 *   %0 on success and a negative error value on failure.
 */
int ccw_driver_register(struct ccw_driver *cdriver)
{
	struct device_driver *drv = &cdriver->driver;

	drv->bus = &ccw_bus_type;

	return driver_register(drv);
}

/**
 * ccw_driver_unregister() - deregister a ccw driver
 * @cdriver: driver to be deregistered
 *
 * This function is mainly a wrapper around driver_unregister().
 */
void ccw_driver_unregister(struct ccw_driver *cdriver)
{
	driver_unregister(&cdriver->driver);
}

static void ccw_device_todo(struct work_struct *work)
{
	struct ccw_device_private *priv;
	struct ccw_device *cdev;
	struct subchannel *sch;
	enum cdev_todo todo;

	priv = container_of(work, struct ccw_device_private, todo_work);
	cdev = priv->cdev;
	sch = to_subchannel(cdev->dev.parent);
	/* Find out todo. */
	spin_lock_irq(cdev->ccwlock);
	todo = priv->todo;
	priv->todo = CDEV_TODO_NOTHING;
	CIO_MSG_EVENT(4, "cdev_todo: cdev=0.%x.%04x todo=%d\n",
		      priv->dev_id.ssid, priv->dev_id.devno, todo);
	spin_unlock_irq(cdev->ccwlock);
	/* Perform todo. */
	switch (todo) {
	case CDEV_TODO_ENABLE_CMF:
		cmf_reenable(cdev);
		break;
	case CDEV_TODO_REBIND:
		ccw_device_do_unbind_bind(cdev);
		break;
	case CDEV_TODO_REGISTER:
		io_subchannel_register(cdev);
		break;
	case CDEV_TODO_UNREG_EVAL:
		if (!sch_is_pseudo_sch(sch))
			css_schedule_eval(sch->schid);
		/* fall-through */
	case CDEV_TODO_UNREG:
		if (sch_is_pseudo_sch(sch))
			ccw_device_unregister(cdev);
		else
			ccw_device_call_sch_unregister(cdev);
		break;
	default:
		break;
	}
	/* Release workqueue ref. */
	put_device(&cdev->dev);
}

/**
 * ccw_device_sched_todo - schedule ccw device operation
 * @cdev: ccw device
 * @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 ccwdev lock held.
 */
void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo)
{
	CIO_MSG_EVENT(4, "cdev_todo: sched cdev=0.%x.%04x todo=%d\n",
		      cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
		      todo);
	if (cdev->private->todo >= todo)
		return;
	cdev->private->todo = todo;
	/* Get workqueue ref. */
	if (!get_device(&cdev->dev))
		return;
	if (!queue_work(cio_work_q, &cdev->private->todo_work)) {
		/* Already queued, release workqueue ref. */
		put_device(&cdev->dev);
	}
}

/**
 * ccw_device_siosl() - initiate logging
 * @cdev: ccw device
 *
 * This function is used to invoke model-dependent logging within the channel
 * subsystem.
 */
int ccw_device_siosl(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	return chsc_siosl(sch->schid);
}
EXPORT_SYMBOL_GPL(ccw_device_siosl);

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);