summaryrefslogtreecommitdiff
path: root/drivers/base/power/domain.c
blob: 8c7d0f33bd53761e118adcc130572c80a1effa57 (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
/*
 * drivers/base/power/domain.c - Common code related to device power domains.
 *
 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
 *
 * This file is released under the GPLv2.
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/pm_qos.h>
#include <linux/pm_clock.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/suspend.h>
#include <linux/export.h>

#include "power.h"

#define GENPD_RETRY_MAX_MS	250		/* Approximate */

#define GENPD_DEV_CALLBACK(genpd, type, callback, dev)		\
({								\
	type (*__routine)(struct device *__d); 			\
	type __ret = (type)0;					\
								\
	__routine = genpd->dev_ops.callback; 			\
	if (__routine) {					\
		__ret = __routine(dev); 			\
	}							\
	__ret;							\
})

static LIST_HEAD(gpd_list);
static DEFINE_MUTEX(gpd_list_lock);

/*
 * Get the generic PM domain for a particular struct device.
 * This validates the struct device pointer, the PM domain pointer,
 * and checks that the PM domain pointer is a real generic PM domain.
 * Any failure results in NULL being returned.
 */
static struct generic_pm_domain *genpd_lookup_dev(struct device *dev)
{
	struct generic_pm_domain *genpd = NULL, *gpd;

	if (IS_ERR_OR_NULL(dev) || IS_ERR_OR_NULL(dev->pm_domain))
		return NULL;

	mutex_lock(&gpd_list_lock);
	list_for_each_entry(gpd, &gpd_list, gpd_list_node) {
		if (&gpd->domain == dev->pm_domain) {
			genpd = gpd;
			break;
		}
	}
	mutex_unlock(&gpd_list_lock);

	return genpd;
}

/*
 * This should only be used where we are certain that the pm_domain
 * attached to the device is a genpd domain.
 */
static struct generic_pm_domain *dev_to_genpd(struct device *dev)
{
	if (IS_ERR_OR_NULL(dev->pm_domain))
		return ERR_PTR(-EINVAL);

	return pd_to_genpd(dev->pm_domain);
}

static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
{
	return GENPD_DEV_CALLBACK(genpd, int, stop, dev);
}

static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev)
{
	return GENPD_DEV_CALLBACK(genpd, int, start, dev);
}

static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)
{
	bool ret = false;

	if (!WARN_ON(atomic_read(&genpd->sd_count) == 0))
		ret = !!atomic_dec_and_test(&genpd->sd_count);

	return ret;
}

static void genpd_sd_counter_inc(struct generic_pm_domain *genpd)
{
	atomic_inc(&genpd->sd_count);
	smp_mb__after_atomic();
}

static int genpd_power_on(struct generic_pm_domain *genpd, bool timed)
{
	unsigned int state_idx = genpd->state_idx;
	ktime_t time_start;
	s64 elapsed_ns;
	int ret;

	if (!genpd->power_on)
		return 0;

	if (!timed)
		return genpd->power_on(genpd);

	time_start = ktime_get();
	ret = genpd->power_on(genpd);
	if (ret)
		return ret;

	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
	if (elapsed_ns <= genpd->states[state_idx].power_on_latency_ns)
		return ret;

	genpd->states[state_idx].power_on_latency_ns = elapsed_ns;
	genpd->max_off_time_changed = true;
	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
		 genpd->name, "on", elapsed_ns);

	return ret;
}

static int genpd_power_off(struct generic_pm_domain *genpd, bool timed)
{
	unsigned int state_idx = genpd->state_idx;
	ktime_t time_start;
	s64 elapsed_ns;
	int ret;

	if (!genpd->power_off)
		return 0;

	if (!timed)
		return genpd->power_off(genpd);

	time_start = ktime_get();
	ret = genpd->power_off(genpd);
	if (ret == -EBUSY)
		return ret;

	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
	if (elapsed_ns <= genpd->states[state_idx].power_off_latency_ns)
		return ret;

	genpd->states[state_idx].power_off_latency_ns = elapsed_ns;
	genpd->max_off_time_changed = true;
	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
		 genpd->name, "off", elapsed_ns);

	return ret;
}

/**
 * genpd_queue_power_off_work - Queue up the execution of genpd_poweroff().
 * @genpd: PM domain to power off.
 *
 * Queue up the execution of genpd_poweroff() unless it's already been done
 * before.
 */
static void genpd_queue_power_off_work(struct generic_pm_domain *genpd)
{
	queue_work(pm_wq, &genpd->power_off_work);
}

/**
 * genpd_poweron - Restore power to a given PM domain and its masters.
 * @genpd: PM domain to power up.
 * @depth: nesting count for lockdep.
 *
 * Restore power to @genpd and all of its masters so that it is possible to
 * resume a device belonging to it.
 */
static int genpd_poweron(struct generic_pm_domain *genpd, unsigned int depth)
{
	struct gpd_link *link;
	int ret = 0;

	if (genpd->status == GPD_STATE_ACTIVE)
		return 0;

	/*
	 * The list is guaranteed not to change while the loop below is being
	 * executed, unless one of the masters' .power_on() callbacks fiddles
	 * with it.
	 */
	list_for_each_entry(link, &genpd->slave_links, slave_node) {
		struct generic_pm_domain *master = link->master;

		genpd_sd_counter_inc(master);

		mutex_lock_nested(&master->lock, depth + 1);
		ret = genpd_poweron(master, depth + 1);
		mutex_unlock(&master->lock);

		if (ret) {
			genpd_sd_counter_dec(master);
			goto err;
		}
	}

	ret = genpd_power_on(genpd, true);
	if (ret)
		goto err;

	genpd->status = GPD_STATE_ACTIVE;
	return 0;

 err:
	list_for_each_entry_continue_reverse(link,
					&genpd->slave_links,
					slave_node) {
		genpd_sd_counter_dec(link->master);
		genpd_queue_power_off_work(link->master);
	}

	return ret;
}

static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
				     unsigned long val, void *ptr)
{
	struct generic_pm_domain_data *gpd_data;
	struct device *dev;

	gpd_data = container_of(nb, struct generic_pm_domain_data, nb);
	dev = gpd_data->base.dev;

	for (;;) {
		struct generic_pm_domain *genpd;
		struct pm_domain_data *pdd;

		spin_lock_irq(&dev->power.lock);

		pdd = dev->power.subsys_data ?
				dev->power.subsys_data->domain_data : NULL;
		if (pdd && pdd->dev) {
			to_gpd_data(pdd)->td.constraint_changed = true;
			genpd = dev_to_genpd(dev);
		} else {
			genpd = ERR_PTR(-ENODATA);
		}

		spin_unlock_irq(&dev->power.lock);

		if (!IS_ERR(genpd)) {
			mutex_lock(&genpd->lock);
			genpd->max_off_time_changed = true;
			mutex_unlock(&genpd->lock);
		}

		dev = dev->parent;
		if (!dev || dev->power.ignore_children)
			break;
	}

	return NOTIFY_DONE;
}

/**
 * genpd_poweroff - Remove power from a given PM domain.
 * @genpd: PM domain to power down.
 * @is_async: PM domain is powered down from a scheduled work
 *
 * If all of the @genpd's devices have been suspended and all of its subdomains
 * have been powered down, remove power from @genpd.
 */
static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async)
{
	struct pm_domain_data *pdd;
	struct gpd_link *link;
	unsigned int not_suspended = 0;

	/*
	 * Do not try to power off the domain in the following situations:
	 * (1) The domain is already in the "power off" state.
	 * (2) System suspend is in progress.
	 */
	if (genpd->status == GPD_STATE_POWER_OFF
	    || genpd->prepared_count > 0)
		return 0;

	if (atomic_read(&genpd->sd_count) > 0)
		return -EBUSY;

	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
		enum pm_qos_flags_status stat;

		stat = dev_pm_qos_flags(pdd->dev,
					PM_QOS_FLAG_NO_POWER_OFF
						| PM_QOS_FLAG_REMOTE_WAKEUP);
		if (stat > PM_QOS_FLAGS_NONE)
			return -EBUSY;

		if (!pm_runtime_suspended(pdd->dev) || pdd->dev->power.irq_safe)
			not_suspended++;
	}

	if (not_suspended > 1 || (not_suspended == 1 && is_async))
		return -EBUSY;

	if (genpd->gov && genpd->gov->power_down_ok) {
		if (!genpd->gov->power_down_ok(&genpd->domain))
			return -EAGAIN;
	}

	if (genpd->power_off) {
		int ret;

		if (atomic_read(&genpd->sd_count) > 0)
			return -EBUSY;

		/*
		 * If sd_count > 0 at this point, one of the subdomains hasn't
		 * managed to call genpd_poweron() for the master yet after
		 * incrementing it.  In that case genpd_poweron() will wait
		 * for us to drop the lock, so we can call .power_off() and let
		 * the genpd_poweron() restore power for us (this shouldn't
		 * happen very often).
		 */
		ret = genpd_power_off(genpd, true);
		if (ret)
			return ret;
	}

	genpd->status = GPD_STATE_POWER_OFF;

	list_for_each_entry(link, &genpd->slave_links, slave_node) {
		genpd_sd_counter_dec(link->master);
		genpd_queue_power_off_work(link->master);
	}

	return 0;
}

/**
 * genpd_power_off_work_fn - Power off PM domain whose subdomain count is 0.
 * @work: Work structure used for scheduling the execution of this function.
 */
static void genpd_power_off_work_fn(struct work_struct *work)
{
	struct generic_pm_domain *genpd;

	genpd = container_of(work, struct generic_pm_domain, power_off_work);

	mutex_lock(&genpd->lock);
	genpd_poweroff(genpd, true);
	mutex_unlock(&genpd->lock);
}

/**
 * __genpd_runtime_suspend - walk the hierarchy of ->runtime_suspend() callbacks
 * @dev: Device to handle.
 */
static int __genpd_runtime_suspend(struct device *dev)
{
	int (*cb)(struct device *__dev);

	if (dev->type && dev->type->pm)
		cb = dev->type->pm->runtime_suspend;
	else if (dev->class && dev->class->pm)
		cb = dev->class->pm->runtime_suspend;
	else if (dev->bus && dev->bus->pm)
		cb = dev->bus->pm->runtime_suspend;
	else
		cb = NULL;

	if (!cb && dev->driver && dev->driver->pm)
		cb = dev->driver->pm->runtime_suspend;

	return cb ? cb(dev) : 0;
}

/**
 * __genpd_runtime_resume - walk the hierarchy of ->runtime_resume() callbacks
 * @dev: Device to handle.
 */
static int __genpd_runtime_resume(struct device *dev)
{
	int (*cb)(struct device *__dev);

	if (dev->type && dev->type->pm)
		cb = dev->type->pm->runtime_resume;
	else if (dev->class && dev->class->pm)
		cb = dev->class->pm->runtime_resume;
	else if (dev->bus && dev->bus->pm)
		cb = dev->bus->pm->runtime_resume;
	else
		cb = NULL;

	if (!cb && dev->driver && dev->driver->pm)
		cb = dev->driver->pm->runtime_resume;

	return cb ? cb(dev) : 0;
}

/**
 * genpd_runtime_suspend - Suspend a device belonging to I/O PM domain.
 * @dev: Device to suspend.
 *
 * Carry out a runtime suspend of a device under the assumption that its
 * pm_domain field points to the domain member of an object of type
 * struct generic_pm_domain representing a PM domain consisting of I/O devices.
 */
static int genpd_runtime_suspend(struct device *dev)
{
	struct generic_pm_domain *genpd;
	bool (*suspend_ok)(struct device *__dev);
	struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
	bool runtime_pm = pm_runtime_enabled(dev);
	ktime_t time_start;
	s64 elapsed_ns;
	int ret;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	/*
	 * A runtime PM centric subsystem/driver may re-use the runtime PM
	 * callbacks for other purposes than runtime PM. In those scenarios
	 * runtime PM is disabled. Under these circumstances, we shall skip
	 * validating/measuring the PM QoS latency.
	 */
	suspend_ok = genpd->gov ? genpd->gov->suspend_ok : NULL;
	if (runtime_pm && suspend_ok && !suspend_ok(dev))
		return -EBUSY;

	/* Measure suspend latency. */
	if (runtime_pm)
		time_start = ktime_get();

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

	ret = genpd_stop_dev(genpd, dev);
	if (ret) {
		__genpd_runtime_resume(dev);
		return ret;
	}

	/* Update suspend latency value if the measured time exceeds it. */
	if (runtime_pm) {
		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
		if (elapsed_ns > td->suspend_latency_ns) {
			td->suspend_latency_ns = elapsed_ns;
			dev_dbg(dev, "suspend latency exceeded, %lld ns\n",
				elapsed_ns);
			genpd->max_off_time_changed = true;
			td->constraint_changed = true;
		}
	}

	/*
	 * If power.irq_safe is set, this routine will be run with interrupts
	 * off, so it can't use mutexes.
	 */
	if (dev->power.irq_safe)
		return 0;

	mutex_lock(&genpd->lock);
	genpd_poweroff(genpd, false);
	mutex_unlock(&genpd->lock);

	return 0;
}

/**
 * genpd_runtime_resume - Resume a device belonging to I/O PM domain.
 * @dev: Device to resume.
 *
 * Carry out a runtime resume of a device under the assumption that its
 * pm_domain field points to the domain member of an object of type
 * struct generic_pm_domain representing a PM domain consisting of I/O devices.
 */
static int genpd_runtime_resume(struct device *dev)
{
	struct generic_pm_domain *genpd;
	struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
	bool runtime_pm = pm_runtime_enabled(dev);
	ktime_t time_start;
	s64 elapsed_ns;
	int ret;
	bool timed = true;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	/* If power.irq_safe, the PM domain is never powered off. */
	if (dev->power.irq_safe) {
		timed = false;
		goto out;
	}

	mutex_lock(&genpd->lock);
	ret = genpd_poweron(genpd, 0);
	mutex_unlock(&genpd->lock);

	if (ret)
		return ret;

 out:
	/* Measure resume latency. */
	if (timed && runtime_pm)
		time_start = ktime_get();

	ret = genpd_start_dev(genpd, dev);
	if (ret)
		goto err_poweroff;

	ret = __genpd_runtime_resume(dev);
	if (ret)
		goto err_stop;

	/* Update resume latency value if the measured time exceeds it. */
	if (timed && runtime_pm) {
		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
		if (elapsed_ns > td->resume_latency_ns) {
			td->resume_latency_ns = elapsed_ns;
			dev_dbg(dev, "resume latency exceeded, %lld ns\n",
				elapsed_ns);
			genpd->max_off_time_changed = true;
			td->constraint_changed = true;
		}
	}

	return 0;

err_stop:
	genpd_stop_dev(genpd, dev);
err_poweroff:
	if (!dev->power.irq_safe) {
		mutex_lock(&genpd->lock);
		genpd_poweroff(genpd, 0);
		mutex_unlock(&genpd->lock);
	}

	return ret;
}

static bool pd_ignore_unused;
static int __init pd_ignore_unused_setup(char *__unused)
{
	pd_ignore_unused = true;
	return 1;
}
__setup("pd_ignore_unused", pd_ignore_unused_setup);

/**
 * genpd_poweroff_unused - Power off all PM domains with no devices in use.
 */
static int __init genpd_poweroff_unused(void)
{
	struct generic_pm_domain *genpd;

	if (pd_ignore_unused) {
		pr_warn("genpd: Not disabling unused power domains\n");
		return 0;
	}

	mutex_lock(&gpd_list_lock);

	list_for_each_entry(genpd, &gpd_list, gpd_list_node)
		genpd_queue_power_off_work(genpd);

	mutex_unlock(&gpd_list_lock);

	return 0;
}
late_initcall(genpd_poweroff_unused);

#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM_GENERIC_DOMAINS_OF)

/**
 * pm_genpd_present - Check if the given PM domain has been initialized.
 * @genpd: PM domain to check.
 */
static bool pm_genpd_present(const struct generic_pm_domain *genpd)
{
	const struct generic_pm_domain *gpd;

	if (IS_ERR_OR_NULL(genpd))
		return false;

	list_for_each_entry(gpd, &gpd_list, gpd_list_node)
		if (gpd == genpd)
			return true;

	return false;
}

#endif

#ifdef CONFIG_PM_SLEEP

static bool genpd_dev_active_wakeup(struct generic_pm_domain *genpd,
				    struct device *dev)
{
	return GENPD_DEV_CALLBACK(genpd, bool, active_wakeup, dev);
}

/**
 * genpd_sync_poweroff - Synchronously power off a PM domain and its masters.
 * @genpd: PM domain to power off, if possible.
 *
 * Check if the given PM domain can be powered off (during system suspend or
 * hibernation) and do that if so.  Also, in that case propagate to its masters.
 *
 * This function is only called in "noirq" and "syscore" stages of system power
 * transitions, so it need not acquire locks (all of the "noirq" callbacks are
 * executed sequentially, so it is guaranteed that it will never run twice in
 * parallel).
 */
static void genpd_sync_poweroff(struct generic_pm_domain *genpd)
{
	struct gpd_link *link;

	if (genpd->status == GPD_STATE_POWER_OFF)
		return;

	if (genpd->suspended_count != genpd->device_count
	    || atomic_read(&genpd->sd_count) > 0)
		return;

	/* Choose the deepest state when suspending */
	genpd->state_idx = genpd->state_count - 1;
	genpd_power_off(genpd, false);

	genpd->status = GPD_STATE_POWER_OFF;

	list_for_each_entry(link, &genpd->slave_links, slave_node) {
		genpd_sd_counter_dec(link->master);
		genpd_sync_poweroff(link->master);
	}
}

/**
 * genpd_sync_poweron - Synchronously power on a PM domain and its masters.
 * @genpd: PM domain to power on.
 *
 * This function is only called in "noirq" and "syscore" stages of system power
 * transitions, so it need not acquire locks (all of the "noirq" callbacks are
 * executed sequentially, so it is guaranteed that it will never run twice in
 * parallel).
 */
static void genpd_sync_poweron(struct generic_pm_domain *genpd)
{
	struct gpd_link *link;

	if (genpd->status == GPD_STATE_ACTIVE)
		return;

	list_for_each_entry(link, &genpd->slave_links, slave_node) {
		genpd_sync_poweron(link->master);
		genpd_sd_counter_inc(link->master);
	}

	genpd_power_on(genpd, false);

	genpd->status = GPD_STATE_ACTIVE;
}

/**
 * resume_needed - Check whether to resume a device before system suspend.
 * @dev: Device to check.
 * @genpd: PM domain the device belongs to.
 *
 * There are two cases in which a device that can wake up the system from sleep
 * states should be resumed by pm_genpd_prepare(): (1) if the device is enabled
 * to wake up the system and it has to remain active for this purpose while the
 * system is in the sleep state and (2) if the device is not enabled to wake up
 * the system from sleep states and it generally doesn't generate wakeup signals
 * by itself (those signals are generated on its behalf by other parts of the
 * system).  In the latter case it may be necessary to reconfigure the device's
 * wakeup settings during system suspend, because it may have been set up to
 * signal remote wakeup from the system's working state as needed by runtime PM.
 * Return 'true' in either of the above cases.
 */
static bool resume_needed(struct device *dev, struct generic_pm_domain *genpd)
{
	bool active_wakeup;

	if (!device_can_wakeup(dev))
		return false;

	active_wakeup = genpd_dev_active_wakeup(genpd, dev);
	return device_may_wakeup(dev) ? active_wakeup : !active_wakeup;
}

/**
 * pm_genpd_prepare - Start power transition of a device in a PM domain.
 * @dev: Device to start the transition of.
 *
 * Start a power transition of a device (during a system-wide power transition)
 * under the assumption that its pm_domain field points to the domain member of
 * an object of type struct generic_pm_domain representing a PM domain
 * consisting of I/O devices.
 */
static int pm_genpd_prepare(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	/*
	 * If a wakeup request is pending for the device, it should be woken up
	 * at this point and a system wakeup event should be reported if it's
	 * set up to wake up the system from sleep states.
	 */
	if (resume_needed(dev, genpd))
		pm_runtime_resume(dev);

	mutex_lock(&genpd->lock);

	if (genpd->prepared_count++ == 0)
		genpd->suspended_count = 0;

	mutex_unlock(&genpd->lock);

	ret = pm_generic_prepare(dev);
	if (ret) {
		mutex_lock(&genpd->lock);

		genpd->prepared_count--;

		mutex_unlock(&genpd->lock);
	}

	return ret;
}

/**
 * pm_genpd_suspend_noirq - Completion of suspend of device in an I/O PM domain.
 * @dev: Device to suspend.
 *
 * Stop the device and remove power from the domain if all devices in it have
 * been stopped.
 */
static int pm_genpd_suspend_noirq(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	if (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev))
		return 0;

	if (genpd->dev_ops.stop && genpd->dev_ops.start) {
		ret = pm_runtime_force_suspend(dev);
		if (ret)
			return ret;
	}

	/*
	 * Since all of the "noirq" callbacks are executed sequentially, it is
	 * guaranteed that this function will never run twice in parallel for
	 * the same PM domain, so it is not necessary to use locking here.
	 */
	genpd->suspended_count++;
	genpd_sync_poweroff(genpd);

	return 0;
}

/**
 * pm_genpd_resume_noirq - Start of resume of device in an I/O PM domain.
 * @dev: Device to resume.
 *
 * Restore power to the device's PM domain, if necessary, and start the device.
 */
static int pm_genpd_resume_noirq(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	if (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev))
		return 0;

	/*
	 * Since all of the "noirq" callbacks are executed sequentially, it is
	 * guaranteed that this function will never run twice in parallel for
	 * the same PM domain, so it is not necessary to use locking here.
	 */
	genpd_sync_poweron(genpd);
	genpd->suspended_count--;

	if (genpd->dev_ops.stop && genpd->dev_ops.start)
		ret = pm_runtime_force_resume(dev);

	return ret;
}

/**
 * pm_genpd_freeze_noirq - Completion of freezing a device in an I/O PM domain.
 * @dev: Device to freeze.
 *
 * Carry out a late freeze of a device under the assumption that its
 * pm_domain field points to the domain member of an object of type
 * struct generic_pm_domain representing a power domain consisting of I/O
 * devices.
 */
static int pm_genpd_freeze_noirq(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	if (genpd->dev_ops.stop && genpd->dev_ops.start)
		ret = pm_runtime_force_suspend(dev);

	return ret;
}

/**
 * pm_genpd_thaw_noirq - Early thaw of device in an I/O PM domain.
 * @dev: Device to thaw.
 *
 * Start the device, unless power has been removed from the domain already
 * before the system transition.
 */
static int pm_genpd_thaw_noirq(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	if (genpd->dev_ops.stop && genpd->dev_ops.start)
		ret = pm_runtime_force_resume(dev);

	return ret;
}

/**
 * pm_genpd_restore_noirq - Start of restore of device in an I/O PM domain.
 * @dev: Device to resume.
 *
 * Make sure the domain will be in the same power state as before the
 * hibernation the system is resuming from and start the device if necessary.
 */
static int pm_genpd_restore_noirq(struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return -EINVAL;

	/*
	 * Since all of the "noirq" callbacks are executed sequentially, it is
	 * guaranteed that this function will never run twice in parallel for
	 * the same PM domain, so it is not necessary to use locking here.
	 *
	 * At this point suspended_count == 0 means we are being run for the
	 * first time for the given domain in the present cycle.
	 */
	if (genpd->suspended_count++ == 0)
		/*
		 * The boot kernel might put the domain into arbitrary state,
		 * so make it appear as powered off to genpd_sync_poweron(),
		 * so that it tries to power it on in case it was really off.
		 */
		genpd->status = GPD_STATE_POWER_OFF;

	genpd_sync_poweron(genpd);

	if (genpd->dev_ops.stop && genpd->dev_ops.start)
		ret = pm_runtime_force_resume(dev);

	return ret;
}

/**
 * pm_genpd_complete - Complete power transition of a device in a power domain.
 * @dev: Device to complete the transition of.
 *
 * Complete a power transition of a device (during a system-wide power
 * transition) under the assumption that its pm_domain field points to the
 * domain member of an object of type struct generic_pm_domain representing
 * a power domain consisting of I/O devices.
 */
static void pm_genpd_complete(struct device *dev)
{
	struct generic_pm_domain *genpd;

	dev_dbg(dev, "%s()\n", __func__);

	genpd = dev_to_genpd(dev);
	if (IS_ERR(genpd))
		return;

	pm_generic_complete(dev);

	mutex_lock(&genpd->lock);

	genpd->prepared_count--;
	if (!genpd->prepared_count)
		genpd_queue_power_off_work(genpd);

	mutex_unlock(&genpd->lock);
}

/**
 * genpd_syscore_switch - Switch power during system core suspend or resume.
 * @dev: Device that normally is marked as "always on" to switch power for.
 *
 * This routine may only be called during the system core (syscore) suspend or
 * resume phase for devices whose "always on" flags are set.
 */
static void genpd_syscore_switch(struct device *dev, bool suspend)
{
	struct generic_pm_domain *genpd;

	genpd = dev_to_genpd(dev);
	if (!pm_genpd_present(genpd))
		return;

	if (suspend) {
		genpd->suspended_count++;
		genpd_sync_poweroff(genpd);
	} else {
		genpd_sync_poweron(genpd);
		genpd->suspended_count--;
	}
}

void pm_genpd_syscore_poweroff(struct device *dev)
{
	genpd_syscore_switch(dev, true);
}
EXPORT_SYMBOL_GPL(pm_genpd_syscore_poweroff);

void pm_genpd_syscore_poweron(struct device *dev)
{
	genpd_syscore_switch(dev, false);
}
EXPORT_SYMBOL_GPL(pm_genpd_syscore_poweron);

#else /* !CONFIG_PM_SLEEP */

#define pm_genpd_prepare		NULL
#define pm_genpd_suspend_noirq		NULL
#define pm_genpd_resume_noirq		NULL
#define pm_genpd_freeze_noirq		NULL
#define pm_genpd_thaw_noirq		NULL
#define pm_genpd_restore_noirq		NULL
#define pm_genpd_complete		NULL

#endif /* CONFIG_PM_SLEEP */

static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
					struct generic_pm_domain *genpd,
					struct gpd_timing_data *td)
{
	struct generic_pm_domain_data *gpd_data;
	int ret;

	ret = dev_pm_get_subsys_data(dev);
	if (ret)
		return ERR_PTR(ret);

	gpd_data = kzalloc(sizeof(*gpd_data), GFP_KERNEL);
	if (!gpd_data) {
		ret = -ENOMEM;
		goto err_put;
	}

	if (td)
		gpd_data->td = *td;

	gpd_data->base.dev = dev;
	gpd_data->td.constraint_changed = true;
	gpd_data->td.effective_constraint_ns = -1;
	gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier;

	spin_lock_irq(&dev->power.lock);

	if (dev->power.subsys_data->domain_data) {
		ret = -EINVAL;
		goto err_free;
	}

	dev->power.subsys_data->domain_data = &gpd_data->base;

	spin_unlock_irq(&dev->power.lock);

	return gpd_data;

 err_free:
	spin_unlock_irq(&dev->power.lock);
	kfree(gpd_data);
 err_put:
	dev_pm_put_subsys_data(dev);
	return ERR_PTR(ret);
}

static void genpd_free_dev_data(struct device *dev,
				struct generic_pm_domain_data *gpd_data)
{
	spin_lock_irq(&dev->power.lock);

	dev->power.subsys_data->domain_data = NULL;

	spin_unlock_irq(&dev->power.lock);

	kfree(gpd_data);
	dev_pm_put_subsys_data(dev);
}

static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
			    struct gpd_timing_data *td)
{
	struct generic_pm_domain_data *gpd_data;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev))
		return -EINVAL;

	gpd_data = genpd_alloc_dev_data(dev, genpd, td);
	if (IS_ERR(gpd_data))
		return PTR_ERR(gpd_data);

	mutex_lock(&genpd->lock);

	if (genpd->prepared_count > 0) {
		ret = -EAGAIN;
		goto out;
	}

	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
	if (ret)
		goto out;

	dev_pm_domain_set(dev, &genpd->domain);

	genpd->device_count++;
	genpd->max_off_time_changed = true;

	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);

 out:
	mutex_unlock(&genpd->lock);

	if (ret)
		genpd_free_dev_data(dev, gpd_data);
	else
		dev_pm_qos_add_notifier(dev, &gpd_data->nb);

	return ret;
}

/**
 * __pm_genpd_add_device - Add a device to an I/O PM domain.
 * @genpd: PM domain to add the device to.
 * @dev: Device to be added.
 * @td: Set of PM QoS timing parameters to attach to the device.
 */
int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
			  struct gpd_timing_data *td)
{
	int ret;

	mutex_lock(&gpd_list_lock);
	ret = genpd_add_device(genpd, dev, td);
	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(__pm_genpd_add_device);

static int genpd_remove_device(struct generic_pm_domain *genpd,
			       struct device *dev)
{
	struct generic_pm_domain_data *gpd_data;
	struct pm_domain_data *pdd;
	int ret = 0;

	dev_dbg(dev, "%s()\n", __func__);

	pdd = dev->power.subsys_data->domain_data;
	gpd_data = to_gpd_data(pdd);
	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);

	mutex_lock(&genpd->lock);

	if (genpd->prepared_count > 0) {
		ret = -EAGAIN;
		goto out;
	}

	genpd->device_count--;
	genpd->max_off_time_changed = true;

	if (genpd->detach_dev)
		genpd->detach_dev(genpd, dev);

	dev_pm_domain_set(dev, NULL);

	list_del_init(&pdd->list_node);

	mutex_unlock(&genpd->lock);

	genpd_free_dev_data(dev, gpd_data);

	return 0;

 out:
	mutex_unlock(&genpd->lock);
	dev_pm_qos_add_notifier(dev, &gpd_data->nb);

	return ret;
}

/**
 * pm_genpd_remove_device - Remove a device from an I/O PM domain.
 * @genpd: PM domain to remove the device from.
 * @dev: Device to be removed.
 */
int pm_genpd_remove_device(struct generic_pm_domain *genpd,
			   struct device *dev)
{
	if (!genpd || genpd != genpd_lookup_dev(dev))
		return -EINVAL;

	return genpd_remove_device(genpd, dev);
}
EXPORT_SYMBOL_GPL(pm_genpd_remove_device);

static int genpd_add_subdomain(struct generic_pm_domain *genpd,
			       struct generic_pm_domain *subdomain)
{
	struct gpd_link *link, *itr;
	int ret = 0;

	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain)
	    || genpd == subdomain)
		return -EINVAL;

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

	mutex_lock(&subdomain->lock);
	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);

	if (genpd->status == GPD_STATE_POWER_OFF
	    &&  subdomain->status != GPD_STATE_POWER_OFF) {
		ret = -EINVAL;
		goto out;
	}

	list_for_each_entry(itr, &genpd->master_links, master_node) {
		if (itr->slave == subdomain && itr->master == genpd) {
			ret = -EINVAL;
			goto out;
		}
	}

	link->master = genpd;
	list_add_tail(&link->master_node, &genpd->master_links);
	link->slave = subdomain;
	list_add_tail(&link->slave_node, &subdomain->slave_links);
	if (subdomain->status != GPD_STATE_POWER_OFF)
		genpd_sd_counter_inc(genpd);

 out:
	mutex_unlock(&genpd->lock);
	mutex_unlock(&subdomain->lock);
	if (ret)
		kfree(link);
	return ret;
}

/**
 * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
 * @genpd: Master PM domain to add the subdomain to.
 * @subdomain: Subdomain to be added.
 */
int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
			   struct generic_pm_domain *subdomain)
{
	int ret;

	mutex_lock(&gpd_list_lock);
	ret = genpd_add_subdomain(genpd, subdomain);
	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(pm_genpd_add_subdomain);

/**
 * pm_genpd_remove_subdomain - Remove a subdomain from an I/O PM domain.
 * @genpd: Master PM domain to remove the subdomain from.
 * @subdomain: Subdomain to be removed.
 */
int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
			      struct generic_pm_domain *subdomain)
{
	struct gpd_link *l, *link;
	int ret = -EINVAL;

	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain))
		return -EINVAL;

	mutex_lock(&subdomain->lock);
	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);

	if (!list_empty(&subdomain->master_links) || subdomain->device_count) {
		pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
			subdomain->name);
		ret = -EBUSY;
		goto out;
	}

	list_for_each_entry_safe(link, l, &genpd->master_links, master_node) {
		if (link->slave != subdomain)
			continue;

		list_del(&link->master_node);
		list_del(&link->slave_node);
		kfree(link);
		if (subdomain->status != GPD_STATE_POWER_OFF)
			genpd_sd_counter_dec(genpd);

		ret = 0;
		break;
	}

out:
	mutex_unlock(&genpd->lock);
	mutex_unlock(&subdomain->lock);

	return ret;
}
EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);

/**
 * pm_genpd_init - Initialize a generic I/O PM domain object.
 * @genpd: PM domain object to initialize.
 * @gov: PM domain governor to associate with the domain (may be NULL).
 * @is_off: Initial value of the domain's power_is_off field.
 *
 * Returns 0 on successful initialization, else a negative error code.
 */
int pm_genpd_init(struct generic_pm_domain *genpd,
		  struct dev_power_governor *gov, bool is_off)
{
	if (IS_ERR_OR_NULL(genpd))
		return -EINVAL;

	INIT_LIST_HEAD(&genpd->master_links);
	INIT_LIST_HEAD(&genpd->slave_links);
	INIT_LIST_HEAD(&genpd->dev_list);
	mutex_init(&genpd->lock);
	genpd->gov = gov;
	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
	atomic_set(&genpd->sd_count, 0);
	genpd->status = is_off ? GPD_STATE_POWER_OFF : GPD_STATE_ACTIVE;
	genpd->device_count = 0;
	genpd->max_off_time_ns = -1;
	genpd->max_off_time_changed = true;
	genpd->provider = NULL;
	genpd->has_provider = false;
	genpd->domain.ops.runtime_suspend = genpd_runtime_suspend;
	genpd->domain.ops.runtime_resume = genpd_runtime_resume;
	genpd->domain.ops.prepare = pm_genpd_prepare;
	genpd->domain.ops.suspend_noirq = pm_genpd_suspend_noirq;
	genpd->domain.ops.resume_noirq = pm_genpd_resume_noirq;
	genpd->domain.ops.freeze_noirq = pm_genpd_freeze_noirq;
	genpd->domain.ops.thaw_noirq = pm_genpd_thaw_noirq;
	genpd->domain.ops.poweroff_noirq = pm_genpd_suspend_noirq;
	genpd->domain.ops.restore_noirq = pm_genpd_restore_noirq;
	genpd->domain.ops.complete = pm_genpd_complete;

	if (genpd->flags & GENPD_FLAG_PM_CLK) {
		genpd->dev_ops.stop = pm_clk_suspend;
		genpd->dev_ops.start = pm_clk_resume;
	}

	if (genpd->state_idx >= GENPD_MAX_NUM_STATES) {
		pr_warn("Initial state index out of bounds.\n");
		genpd->state_idx = GENPD_MAX_NUM_STATES - 1;
	}

	if (genpd->state_count > GENPD_MAX_NUM_STATES) {
		pr_warn("Limiting states to  %d\n", GENPD_MAX_NUM_STATES);
		genpd->state_count = GENPD_MAX_NUM_STATES;
	}

	/* Use only one "off" state if there were no states declared */
	if (genpd->state_count == 0)
		genpd->state_count = 1;

	mutex_lock(&gpd_list_lock);
	list_add(&genpd->gpd_list_node, &gpd_list);
	mutex_unlock(&gpd_list_lock);

	return 0;
}
EXPORT_SYMBOL_GPL(pm_genpd_init);

static int genpd_remove(struct generic_pm_domain *genpd)
{
	struct gpd_link *l, *link;

	if (IS_ERR_OR_NULL(genpd))
		return -EINVAL;

	mutex_lock(&genpd->lock);

	if (genpd->has_provider) {
		mutex_unlock(&genpd->lock);
		pr_err("Provider present, unable to remove %s\n", genpd->name);
		return -EBUSY;
	}

	if (!list_empty(&genpd->master_links) || genpd->device_count) {
		mutex_unlock(&genpd->lock);
		pr_err("%s: unable to remove %s\n", __func__, genpd->name);
		return -EBUSY;
	}

	list_for_each_entry_safe(link, l, &genpd->slave_links, slave_node) {
		list_del(&link->master_node);
		list_del(&link->slave_node);
		kfree(link);
	}

	list_del(&genpd->gpd_list_node);
	mutex_unlock(&genpd->lock);
	cancel_work_sync(&genpd->power_off_work);
	pr_debug("%s: removed %s\n", __func__, genpd->name);

	return 0;
}

/**
 * pm_genpd_remove - Remove a generic I/O PM domain
 * @genpd: Pointer to PM domain that is to be removed.
 *
 * To remove the PM domain, this function:
 *  - Removes the PM domain as a subdomain to any parent domains,
 *    if it was added.
 *  - Removes the PM domain from the list of registered PM domains.
 *
 * The PM domain will only be removed, if the associated provider has
 * been removed, it is not a parent to any other PM domain and has no
 * devices associated with it.
 */
int pm_genpd_remove(struct generic_pm_domain *genpd)
{
	int ret;

	mutex_lock(&gpd_list_lock);
	ret = genpd_remove(genpd);
	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(pm_genpd_remove);

#ifdef CONFIG_PM_GENERIC_DOMAINS_OF

typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
						   void *data);

/*
 * Device Tree based PM domain providers.
 *
 * The code below implements generic device tree based PM domain providers that
 * bind device tree nodes with generic PM domains registered in the system.
 *
 * Any driver that registers generic PM domains and needs to support binding of
 * devices to these domains is supposed to register a PM domain provider, which
 * maps a PM domain specifier retrieved from the device tree to a PM domain.
 *
 * Two simple mapping functions have been provided for convenience:
 *  - genpd_xlate_simple() for 1:1 device tree node to PM domain mapping.
 *  - genpd_xlate_onecell() for mapping of multiple PM domains per node by
 *    index.
 */

/**
 * struct of_genpd_provider - PM domain provider registration structure
 * @link: Entry in global list of PM domain providers
 * @node: Pointer to device tree node of PM domain provider
 * @xlate: Provider-specific xlate callback mapping a set of specifier cells
 *         into a PM domain.
 * @data: context pointer to be passed into @xlate callback
 */
struct of_genpd_provider {
	struct list_head link;
	struct device_node *node;
	genpd_xlate_t xlate;
	void *data;
};

/* List of registered PM domain providers. */
static LIST_HEAD(of_genpd_providers);
/* Mutex to protect the list above. */
static DEFINE_MUTEX(of_genpd_mutex);

/**
 * genpd_xlate_simple() - Xlate function for direct node-domain mapping
 * @genpdspec: OF phandle args to map into a PM domain
 * @data: xlate function private data - pointer to struct generic_pm_domain
 *
 * This is a generic xlate function that can be used to model PM domains that
 * have their own device tree nodes. The private data of xlate function needs
 * to be a valid pointer to struct generic_pm_domain.
 */
static struct generic_pm_domain *genpd_xlate_simple(
					struct of_phandle_args *genpdspec,
					void *data)
{
	if (genpdspec->args_count != 0)
		return ERR_PTR(-EINVAL);
	return data;
}

/**
 * genpd_xlate_onecell() - Xlate function using a single index.
 * @genpdspec: OF phandle args to map into a PM domain
 * @data: xlate function private data - pointer to struct genpd_onecell_data
 *
 * This is a generic xlate function that can be used to model simple PM domain
 * controllers that have one device tree node and provide multiple PM domains.
 * A single cell is used as an index into an array of PM domains specified in
 * the genpd_onecell_data struct when registering the provider.
 */
static struct generic_pm_domain *genpd_xlate_onecell(
					struct of_phandle_args *genpdspec,
					void *data)
{
	struct genpd_onecell_data *genpd_data = data;
	unsigned int idx = genpdspec->args[0];

	if (genpdspec->args_count != 1)
		return ERR_PTR(-EINVAL);

	if (idx >= genpd_data->num_domains) {
		pr_err("%s: invalid domain index %u\n", __func__, idx);
		return ERR_PTR(-EINVAL);
	}

	if (!genpd_data->domains[idx])
		return ERR_PTR(-ENOENT);

	return genpd_data->domains[idx];
}

/**
 * genpd_add_provider() - Register a PM domain provider for a node
 * @np: Device node pointer associated with the PM domain provider.
 * @xlate: Callback for decoding PM domain from phandle arguments.
 * @data: Context pointer for @xlate callback.
 */
static int genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
			      void *data)
{
	struct of_genpd_provider *cp;

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

	cp->node = of_node_get(np);
	cp->data = data;
	cp->xlate = xlate;

	mutex_lock(&of_genpd_mutex);
	list_add(&cp->link, &of_genpd_providers);
	mutex_unlock(&of_genpd_mutex);
	pr_debug("Added domain provider from %s\n", np->full_name);

	return 0;
}

/**
 * of_genpd_add_provider_simple() - Register a simple PM domain provider
 * @np: Device node pointer associated with the PM domain provider.
 * @genpd: Pointer to PM domain associated with the PM domain provider.
 */
int of_genpd_add_provider_simple(struct device_node *np,
				 struct generic_pm_domain *genpd)
{
	int ret = -EINVAL;

	if (!np || !genpd)
		return -EINVAL;

	mutex_lock(&gpd_list_lock);

	if (pm_genpd_present(genpd))
		ret = genpd_add_provider(np, genpd_xlate_simple, genpd);

	if (!ret) {
		genpd->provider = &np->fwnode;
		genpd->has_provider = true;
	}

	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(of_genpd_add_provider_simple);

/**
 * of_genpd_add_provider_onecell() - Register a onecell PM domain provider
 * @np: Device node pointer associated with the PM domain provider.
 * @data: Pointer to the data associated with the PM domain provider.
 */
int of_genpd_add_provider_onecell(struct device_node *np,
				  struct genpd_onecell_data *data)
{
	unsigned int i;
	int ret = -EINVAL;

	if (!np || !data)
		return -EINVAL;

	mutex_lock(&gpd_list_lock);

	for (i = 0; i < data->num_domains; i++) {
		if (!data->domains[i])
			continue;
		if (!pm_genpd_present(data->domains[i]))
			goto error;

		data->domains[i]->provider = &np->fwnode;
		data->domains[i]->has_provider = true;
	}

	ret = genpd_add_provider(np, genpd_xlate_onecell, data);
	if (ret < 0)
		goto error;

	mutex_unlock(&gpd_list_lock);

	return 0;

error:
	while (i--) {
		if (!data->domains[i])
			continue;
		data->domains[i]->provider = NULL;
		data->domains[i]->has_provider = false;
	}

	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(of_genpd_add_provider_onecell);

/**
 * of_genpd_del_provider() - Remove a previously registered PM domain provider
 * @np: Device node pointer associated with the PM domain provider
 */
void of_genpd_del_provider(struct device_node *np)
{
	struct of_genpd_provider *cp, *tmp;
	struct generic_pm_domain *gpd;

	mutex_lock(&gpd_list_lock);
	mutex_lock(&of_genpd_mutex);
	list_for_each_entry_safe(cp, tmp, &of_genpd_providers, link) {
		if (cp->node == np) {
			/*
			 * For each PM domain associated with the
			 * provider, set the 'has_provider' to false
			 * so that the PM domain can be safely removed.
			 */
			list_for_each_entry(gpd, &gpd_list, gpd_list_node)
				if (gpd->provider == &np->fwnode)
					gpd->has_provider = false;

			list_del(&cp->link);
			of_node_put(cp->node);
			kfree(cp);
			break;
		}
	}
	mutex_unlock(&of_genpd_mutex);
	mutex_unlock(&gpd_list_lock);
}
EXPORT_SYMBOL_GPL(of_genpd_del_provider);

/**
 * genpd_get_from_provider() - Look-up PM domain
 * @genpdspec: OF phandle args to use for look-up
 *
 * Looks for a PM domain provider under the node specified by @genpdspec and if
 * found, uses xlate function of the provider to map phandle args to a PM
 * domain.
 *
 * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
 * on failure.
 */
static struct generic_pm_domain *genpd_get_from_provider(
					struct of_phandle_args *genpdspec)
{
	struct generic_pm_domain *genpd = ERR_PTR(-ENOENT);
	struct of_genpd_provider *provider;

	if (!genpdspec)
		return ERR_PTR(-EINVAL);

	mutex_lock(&of_genpd_mutex);

	/* Check if we have such a provider in our array */
	list_for_each_entry(provider, &of_genpd_providers, link) {
		if (provider->node == genpdspec->np)
			genpd = provider->xlate(genpdspec, provider->data);
		if (!IS_ERR(genpd))
			break;
	}

	mutex_unlock(&of_genpd_mutex);

	return genpd;
}

/**
 * of_genpd_add_device() - Add a device to an I/O PM domain
 * @genpdspec: OF phandle args to use for look-up PM domain
 * @dev: Device to be added.
 *
 * Looks-up an I/O PM domain based upon phandle args provided and adds
 * the device to the PM domain. Returns a negative error code on failure.
 */
int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev)
{
	struct generic_pm_domain *genpd;
	int ret;

	mutex_lock(&gpd_list_lock);

	genpd = genpd_get_from_provider(genpdspec);
	if (IS_ERR(genpd)) {
		ret = PTR_ERR(genpd);
		goto out;
	}

	ret = genpd_add_device(genpd, dev, NULL);

out:
	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(of_genpd_add_device);

/**
 * of_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
 * @parent_spec: OF phandle args to use for parent PM domain look-up
 * @subdomain_spec: OF phandle args to use for subdomain look-up
 *
 * Looks-up a parent PM domain and subdomain based upon phandle args
 * provided and adds the subdomain to the parent PM domain. Returns a
 * negative error code on failure.
 */
int of_genpd_add_subdomain(struct of_phandle_args *parent_spec,
			   struct of_phandle_args *subdomain_spec)
{
	struct generic_pm_domain *parent, *subdomain;
	int ret;

	mutex_lock(&gpd_list_lock);

	parent = genpd_get_from_provider(parent_spec);
	if (IS_ERR(parent)) {
		ret = PTR_ERR(parent);
		goto out;
	}

	subdomain = genpd_get_from_provider(subdomain_spec);
	if (IS_ERR(subdomain)) {
		ret = PTR_ERR(subdomain);
		goto out;
	}

	ret = genpd_add_subdomain(parent, subdomain);

out:
	mutex_unlock(&gpd_list_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(of_genpd_add_subdomain);

/**
 * of_genpd_remove_last - Remove the last PM domain registered for a provider
 * @provider: Pointer to device structure associated with provider
 *
 * Find the last PM domain that was added by a particular provider and
 * remove this PM domain from the list of PM domains. The provider is
 * identified by the 'provider' device structure that is passed. The PM
 * domain will only be removed, if the provider associated with domain
 * has been removed.
 *
 * Returns a valid pointer to struct generic_pm_domain on success or
 * ERR_PTR() on failure.
 */
struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
{
	struct generic_pm_domain *gpd, *tmp, *genpd = ERR_PTR(-ENOENT);
	int ret;

	if (IS_ERR_OR_NULL(np))
		return ERR_PTR(-EINVAL);

	mutex_lock(&gpd_list_lock);
	list_for_each_entry_safe(gpd, tmp, &gpd_list, gpd_list_node) {
		if (gpd->provider == &np->fwnode) {
			ret = genpd_remove(gpd);
			genpd = ret ? ERR_PTR(ret) : gpd;
			break;
		}
	}
	mutex_unlock(&gpd_list_lock);

	return genpd;
}
EXPORT_SYMBOL_GPL(of_genpd_remove_last);

/**
 * genpd_dev_pm_detach - Detach a device from its PM domain.
 * @dev: Device to detach.
 * @power_off: Currently not used
 *
 * Try to locate a corresponding generic PM domain, which the device was
 * attached to previously. If such is found, the device is detached from it.
 */
static void genpd_dev_pm_detach(struct device *dev, bool power_off)
{
	struct generic_pm_domain *pd;
	unsigned int i;
	int ret = 0;

	pd = dev_to_genpd(dev);
	if (IS_ERR(pd))
		return;

	dev_dbg(dev, "removing from PM domain %s\n", pd->name);

	for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
		ret = genpd_remove_device(pd, dev);
		if (ret != -EAGAIN)
			break;

		mdelay(i);
		cond_resched();
	}

	if (ret < 0) {
		dev_err(dev, "failed to remove from PM domain %s: %d",
			pd->name, ret);
		return;
	}

	/* Check if PM domain can be powered off after removing this device. */
	genpd_queue_power_off_work(pd);
}

static void genpd_dev_pm_sync(struct device *dev)
{
	struct generic_pm_domain *pd;

	pd = dev_to_genpd(dev);
	if (IS_ERR(pd))
		return;

	genpd_queue_power_off_work(pd);
}

/**
 * genpd_dev_pm_attach - Attach a device to its PM domain using DT.
 * @dev: Device to attach.
 *
 * Parse device's OF node to find a PM domain specifier. If such is found,
 * attaches the device to retrieved pm_domain ops.
 *
 * Both generic and legacy Samsung-specific DT bindings are supported to keep
 * backwards compatibility with existing DTBs.
 *
 * Returns 0 on successfully attached PM domain or negative error code. Note
 * that if a power-domain exists for the device, but it cannot be found or
 * turned on, then return -EPROBE_DEFER to ensure that the device is not
 * probed and to re-try again later.
 */
int genpd_dev_pm_attach(struct device *dev)
{
	struct of_phandle_args pd_args;
	struct generic_pm_domain *pd;
	unsigned int i;
	int ret;

	if (!dev->of_node)
		return -ENODEV;

	if (dev->pm_domain)
		return -EEXIST;

	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
					"#power-domain-cells", 0, &pd_args);
	if (ret < 0) {
		if (ret != -ENOENT)
			return ret;

		/*
		 * Try legacy Samsung-specific bindings
		 * (for backwards compatibility of DT ABI)
		 */
		pd_args.args_count = 0;
		pd_args.np = of_parse_phandle(dev->of_node,
						"samsung,power-domain", 0);
		if (!pd_args.np)
			return -ENOENT;
	}

	mutex_lock(&gpd_list_lock);
	pd = genpd_get_from_provider(&pd_args);
	of_node_put(pd_args.np);
	if (IS_ERR(pd)) {
		mutex_unlock(&gpd_list_lock);
		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
			__func__, PTR_ERR(pd));
		return -EPROBE_DEFER;
	}

	dev_dbg(dev, "adding to PM domain %s\n", pd->name);

	for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
		ret = genpd_add_device(pd, dev, NULL);
		if (ret != -EAGAIN)
			break;

		mdelay(i);
		cond_resched();
	}
	mutex_unlock(&gpd_list_lock);

	if (ret < 0) {
		dev_err(dev, "failed to add to PM domain %s: %d",
			pd->name, ret);
		goto out;
	}

	dev->pm_domain->detach = genpd_dev_pm_detach;
	dev->pm_domain->sync = genpd_dev_pm_sync;

	mutex_lock(&pd->lock);
	ret = genpd_poweron(pd, 0);
	mutex_unlock(&pd->lock);
out:
	return ret ? -EPROBE_DEFER : 0;
}
EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */


/***        debugfs support        ***/

#ifdef CONFIG_DEBUG_FS
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/kobject.h>
static struct dentry *pm_genpd_debugfs_dir;

/*
 * TODO: This function is a slightly modified version of rtpm_status_show
 * from sysfs.c, so generalize it.
 */
static void rtpm_status_str(struct seq_file *s, struct device *dev)
{
	static const char * const status_lookup[] = {
		[RPM_ACTIVE] = "active",
		[RPM_RESUMING] = "resuming",
		[RPM_SUSPENDED] = "suspended",
		[RPM_SUSPENDING] = "suspending"
	};
	const char *p = "";

	if (dev->power.runtime_error)
		p = "error";
	else if (dev->power.disable_depth)
		p = "unsupported";
	else if (dev->power.runtime_status < ARRAY_SIZE(status_lookup))
		p = status_lookup[dev->power.runtime_status];
	else
		WARN_ON(1);

	seq_puts(s, p);
}

static int pm_genpd_summary_one(struct seq_file *s,
				struct generic_pm_domain *genpd)
{
	static const char * const status_lookup[] = {
		[GPD_STATE_ACTIVE] = "on",
		[GPD_STATE_POWER_OFF] = "off"
	};
	struct pm_domain_data *pm_data;
	const char *kobj_path;
	struct gpd_link *link;
	char state[16];
	int ret;

	ret = mutex_lock_interruptible(&genpd->lock);
	if (ret)
		return -ERESTARTSYS;

	if (WARN_ON(genpd->status >= ARRAY_SIZE(status_lookup)))
		goto exit;
	if (genpd->status == GPD_STATE_POWER_OFF)
		snprintf(state, sizeof(state), "%s-%u",
			 status_lookup[genpd->status], genpd->state_idx);
	else
		snprintf(state, sizeof(state), "%s",
			 status_lookup[genpd->status]);
	seq_printf(s, "%-30s  %-15s ", genpd->name, state);

	/*
	 * Modifications on the list require holding locks on both
	 * master and slave, so we are safe.
	 * Also genpd->name is immutable.
	 */
	list_for_each_entry(link, &genpd->master_links, master_node) {
		seq_printf(s, "%s", link->slave->name);
		if (!list_is_last(&link->master_node, &genpd->master_links))
			seq_puts(s, ", ");
	}

	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
		kobj_path = kobject_get_path(&pm_data->dev->kobj, GFP_KERNEL);
		if (kobj_path == NULL)
			continue;

		seq_printf(s, "\n    %-50s  ", kobj_path);
		rtpm_status_str(s, pm_data->dev);
		kfree(kobj_path);
	}

	seq_puts(s, "\n");
exit:
	mutex_unlock(&genpd->lock);

	return 0;
}

static int pm_genpd_summary_show(struct seq_file *s, void *data)
{
	struct generic_pm_domain *genpd;
	int ret = 0;

	seq_puts(s, "domain                          status          slaves\n");
	seq_puts(s, "    /device                                             runtime status\n");
	seq_puts(s, "----------------------------------------------------------------------\n");

	ret = mutex_lock_interruptible(&gpd_list_lock);
	if (ret)
		return -ERESTARTSYS;

	list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
		ret = pm_genpd_summary_one(s, genpd);
		if (ret)
			break;
	}
	mutex_unlock(&gpd_list_lock);

	return ret;
}

static int pm_genpd_summary_open(struct inode *inode, struct file *file)
{
	return single_open(file, pm_genpd_summary_show, NULL);
}

static const struct file_operations pm_genpd_summary_fops = {
	.open = pm_genpd_summary_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init pm_genpd_debug_init(void)
{
	struct dentry *d;

	pm_genpd_debugfs_dir = debugfs_create_dir("pm_genpd", NULL);

	if (!pm_genpd_debugfs_dir)
		return -ENOMEM;

	d = debugfs_create_file("pm_genpd_summary", S_IRUGO,
			pm_genpd_debugfs_dir, NULL, &pm_genpd_summary_fops);
	if (!d)
		return -ENOMEM;

	return 0;
}
late_initcall(pm_genpd_debug_init);

static void __exit pm_genpd_debug_exit(void)
{
	debugfs_remove_recursive(pm_genpd_debugfs_dir);
}
__exitcall(pm_genpd_debug_exit);
#endif /* CONFIG_DEBUG_FS */