summaryrefslogtreecommitdiffstats
path: root/drivers/base/power/opp.c
blob: 7ae7cd990fbf79bf39de570a6a0fca5bd47cef94 (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
/*
 * Generic OPP Interface
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/pm_opp.h>
#include <linux/of.h>
#include <linux/export.h>

/*
 * Internal data structure organization with the OPP layer library is as
 * follows:
 * dev_opp_list (root)
 *	|- device 1 (represents voltage domain 1)
 *	|	|- opp 1 (availability, freq, voltage)
 *	|	|- opp 2 ..
 *	...	...
 *	|	`- opp n ..
 *	|- device 2 (represents the next voltage domain)
 *	...
 *	`- device m (represents mth voltage domain)
 * device 1, 2.. are represented by dev_opp structure while each opp
 * is represented by the opp structure.
 */

/**
 * struct dev_pm_opp - Generic OPP description structure
 * @node:	opp list node. The nodes are maintained throughout the lifetime
 *		of boot. It is expected only an optimal set of OPPs are
 *		added to the library by the SoC framework.
 *		RCU usage: opp list is traversed with RCU locks. node
 *		modification is possible realtime, hence the modifications
 *		are protected by the dev_opp_list_lock for integrity.
 *		IMPORTANT: the opp nodes should be maintained in increasing
 *		order.
 * @dynamic:	not-created from static DT entries.
 * @available:	true/false - marks if this OPP as available or not
 * @turbo:	true if turbo (boost) OPP
 * @rate:	Frequency in hertz
 * @u_volt:	Target voltage in microvolts corresponding to this OPP
 * @u_volt_min:	Minimum voltage in microvolts corresponding to this OPP
 * @u_volt_max:	Maximum voltage in microvolts corresponding to this OPP
 * @u_amp:	Maximum current drawn by the device in microamperes
 * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
 *		frequency from any other OPP's frequency.
 * @dev_opp:	points back to the device_opp struct this opp belongs to
 * @rcu_head:	RCU callback head used for deferred freeing
 * @np:		OPP's device node.
 *
 * This structure stores the OPP information for a given device.
 */
struct dev_pm_opp {
	struct list_head node;

	bool available;
	bool dynamic;
	bool turbo;
	unsigned long rate;

	unsigned long u_volt;
	unsigned long u_volt_min;
	unsigned long u_volt_max;
	unsigned long u_amp;
	unsigned long clock_latency_ns;

	struct device_opp *dev_opp;
	struct rcu_head rcu_head;

	struct device_node *np;
};

/**
 * struct device_list_opp - devices managed by 'struct device_opp'
 * @node:	list node
 * @dev:	device to which the struct object belongs
 * @rcu_head:	RCU callback head used for deferred freeing
 *
 * This is an internal data structure maintaining the list of devices that are
 * managed by 'struct device_opp'.
 */
struct device_list_opp {
	struct list_head node;
	const struct device *dev;
	struct rcu_head rcu_head;
};

/**
 * struct device_opp - Device opp structure
 * @node:	list node - contains the devices with OPPs that
 *		have been registered. Nodes once added are not modified in this
 *		list.
 *		RCU usage: nodes are not modified in the list of device_opp,
 *		however addition is possible and is secured by dev_opp_list_lock
 * @srcu_head:	notifier head to notify the OPP availability changes.
 * @rcu_head:	RCU callback head used for deferred freeing
 * @dev_list:	list of devices that share these OPPs
 * @opp_list:	list of opps
 * @np:		struct device_node pointer for opp's DT node.
 * @shared_opp: OPP is shared between multiple devices.
 *
 * This is an internal data structure maintaining the link to opps attached to
 * a device. This structure is not meant to be shared to users as it is
 * meant for book keeping and private to OPP library.
 *
 * Because the opp structures can be used from both rcu and srcu readers, we
 * need to wait for the grace period of both of them before freeing any
 * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
 */
struct device_opp {
	struct list_head node;

	struct srcu_notifier_head srcu_head;
	struct rcu_head rcu_head;
	struct list_head dev_list;
	struct list_head opp_list;

	struct device_node *np;
	unsigned long clock_latency_ns_max;
	bool shared_opp;
	struct dev_pm_opp *suspend_opp;
};

/*
 * The root of the list of all devices. All device_opp structures branch off
 * from here, with each device_opp containing the list of opp it supports in
 * various states of availability.
 */
static LIST_HEAD(dev_opp_list);
/* Lock to allow exclusive modification to the device and opp lists */
static DEFINE_MUTEX(dev_opp_list_lock);

#define opp_rcu_lockdep_assert()					\
do {									\
	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
				!lockdep_is_held(&dev_opp_list_lock),	\
			   "Missing rcu_read_lock() or "		\
			   "dev_opp_list_lock protection");		\
} while (0)

static struct device_list_opp *_find_list_dev(const struct device *dev,
					      struct device_opp *dev_opp)
{
	struct device_list_opp *list_dev;

	list_for_each_entry(list_dev, &dev_opp->dev_list, node)
		if (list_dev->dev == dev)
			return list_dev;

	return NULL;
}

static struct device_opp *_managed_opp(const struct device_node *np)
{
	struct device_opp *dev_opp;

	list_for_each_entry_rcu(dev_opp, &dev_opp_list, node) {
		if (dev_opp->np == np) {
			/*
			 * Multiple devices can point to the same OPP table and
			 * so will have same node-pointer, np.
			 *
			 * But the OPPs will be considered as shared only if the
			 * OPP table contains a "opp-shared" property.
			 */
			return dev_opp->shared_opp ? dev_opp : NULL;
		}
	}

	return NULL;
}

/**
 * _find_device_opp() - find device_opp struct using device pointer
 * @dev:	device pointer used to lookup device OPPs
 *
 * Search list of device OPPs for one containing matching device. Does a RCU
 * reader operation to grab the pointer needed.
 *
 * Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
 * -EINVAL based on type of error.
 *
 * Locking: This function must be called under rcu_read_lock(). device_opp
 * is a RCU protected pointer. This means that device_opp is valid as long
 * as we are under RCU lock.
 */
static struct device_opp *_find_device_opp(struct device *dev)
{
	struct device_opp *dev_opp;

	if (IS_ERR_OR_NULL(dev)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	list_for_each_entry_rcu(dev_opp, &dev_opp_list, node)
		if (_find_list_dev(dev, dev_opp))
			return dev_opp;

	return ERR_PTR(-ENODEV);
}

/**
 * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
 * @opp:	opp for which voltage has to be returned for
 *
 * Return: voltage in micro volt corresponding to the opp, else
 * return 0
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. This means that opp which could have been fetched by
 * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
 * under RCU lock. The pointer returned by the opp_find_freq family must be
 * used in the same section as the usage of this function with the pointer
 * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
 * pointer.
 */
unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
	struct dev_pm_opp *tmp_opp;
	unsigned long v = 0;

	opp_rcu_lockdep_assert();

	tmp_opp = rcu_dereference(opp);
	if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
		pr_err("%s: Invalid parameters\n", __func__);
	else
		v = tmp_opp->u_volt;

	return v;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);

/**
 * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
 * @opp:	opp for which frequency has to be returned for
 *
 * Return: frequency in hertz corresponding to the opp, else
 * return 0
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. This means that opp which could have been fetched by
 * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
 * under RCU lock. The pointer returned by the opp_find_freq family must be
 * used in the same section as the usage of this function with the pointer
 * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
 * pointer.
 */
unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
{
	struct dev_pm_opp *tmp_opp;
	unsigned long f = 0;

	opp_rcu_lockdep_assert();

	tmp_opp = rcu_dereference(opp);
	if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
		pr_err("%s: Invalid parameters\n", __func__);
	else
		f = tmp_opp->rate;

	return f;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);

/**
 * dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
 * @opp: opp for which turbo mode is being verified
 *
 * Turbo OPPs are not for normal use, and can be enabled (under certain
 * conditions) for short duration of times to finish high throughput work
 * quickly. Running on them for longer times may overheat the chip.
 *
 * Return: true if opp is turbo opp, else false.
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. This means that opp which could have been fetched by
 * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
 * under RCU lock. The pointer returned by the opp_find_freq family must be
 * used in the same section as the usage of this function with the pointer
 * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
 * pointer.
 */
bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
{
	struct dev_pm_opp *tmp_opp;

	opp_rcu_lockdep_assert();

	tmp_opp = rcu_dereference(opp);
	if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
		pr_err("%s: Invalid parameters\n", __func__);
		return false;
	}

	return tmp_opp->turbo;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);

/**
 * dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
 * @dev:	device for which we do this operation
 *
 * Return: This function returns the max clock latency in nanoseconds.
 *
 * Locking: This function takes rcu_read_lock().
 */
unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
{
	struct device_opp *dev_opp;
	unsigned long clock_latency_ns;

	rcu_read_lock();

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp))
		clock_latency_ns = 0;
	else
		clock_latency_ns = dev_opp->clock_latency_ns_max;

	rcu_read_unlock();
	return clock_latency_ns;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);

/**
 * dev_pm_opp_get_suspend_opp() - Get suspend opp
 * @dev:	device for which we do this operation
 *
 * Return: This function returns pointer to the suspend opp if it is
 * defined and available, otherwise it returns NULL.
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. The reason for the same is that the opp pointer which is
 * returned will remain valid for use with opp_get_{voltage, freq} only while
 * under the locked area. The pointer returned must be used prior to unlocking
 * with rcu_read_unlock() to maintain the integrity of the pointer.
 */
struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
{
	struct device_opp *dev_opp;

	opp_rcu_lockdep_assert();

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp) || !dev_opp->suspend_opp ||
	    !dev_opp->suspend_opp->available)
		return NULL;

	return dev_opp->suspend_opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp);

/**
 * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
 * @dev:	device for which we do this operation
 *
 * Return: This function returns the number of available opps if there are any,
 * else returns 0 if none or the corresponding error value.
 *
 * Locking: This function takes rcu_read_lock().
 */
int dev_pm_opp_get_opp_count(struct device *dev)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *temp_opp;
	int count = 0;

	rcu_read_lock();

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp)) {
		count = PTR_ERR(dev_opp);
		dev_err(dev, "%s: device OPP not found (%d)\n",
			__func__, count);
		goto out_unlock;
	}

	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
		if (temp_opp->available)
			count++;
	}

out_unlock:
	rcu_read_unlock();
	return count;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);

/**
 * dev_pm_opp_find_freq_exact() - search for an exact frequency
 * @dev:		device for which we do this operation
 * @freq:		frequency to search for
 * @available:		true/false - match for available opp
 *
 * Return: Searches for exact match in the opp list and returns pointer to the
 * matching opp if found, else returns ERR_PTR in case of error and should
 * be handled using IS_ERR. Error return values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * Note: available is a modifier for the search. if available=true, then the
 * match is for exact matching frequency and is available in the stored OPP
 * table. if false, the match is for exact frequency which is not available.
 *
 * This provides a mechanism to enable an opp which is not available currently
 * or the opposite as well.
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. The reason for the same is that the opp pointer which is
 * returned will remain valid for use with opp_get_{voltage, freq} only while
 * under the locked area. The pointer returned must be used prior to unlocking
 * with rcu_read_unlock() to maintain the integrity of the pointer.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
					      unsigned long freq,
					      bool available)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

	opp_rcu_lockdep_assert();

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp)) {
		int r = PTR_ERR(dev_opp);
		dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
		return ERR_PTR(r);
	}

	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
		if (temp_opp->available == available &&
				temp_opp->rate == freq) {
			opp = temp_opp;
			break;
		}
	}

	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);

/**
 * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
 * @dev:	device for which we do this operation
 * @freq:	Start frequency
 *
 * Search for the matching ceil *available* OPP from a starting freq
 * for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. The reason for the same is that the opp pointer which is
 * returned will remain valid for use with opp_get_{voltage, freq} only while
 * under the locked area. The pointer returned must be used prior to unlocking
 * with rcu_read_unlock() to maintain the integrity of the pointer.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
					     unsigned long *freq)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

	opp_rcu_lockdep_assert();

	if (!dev || !freq) {
		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
		return ERR_PTR(-EINVAL);
	}

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp))
		return ERR_CAST(dev_opp);

	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
		if (temp_opp->available && temp_opp->rate >= *freq) {
			opp = temp_opp;
			*freq = opp->rate;
			break;
		}
	}

	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);

/**
 * dev_pm_opp_find_freq_floor() - Search for a rounded floor freq
 * @dev:	device for which we do this operation
 * @freq:	Start frequency
 *
 * Search for the matching floor *available* OPP from a starting freq
 * for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
 * protected pointer. The reason for the same is that the opp pointer which is
 * returned will remain valid for use with opp_get_{voltage, freq} only while
 * under the locked area. The pointer returned must be used prior to unlocking
 * with rcu_read_unlock() to maintain the integrity of the pointer.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
					      unsigned long *freq)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

	opp_rcu_lockdep_assert();

	if (!dev || !freq) {
		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
		return ERR_PTR(-EINVAL);
	}

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp))
		return ERR_CAST(dev_opp);

	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
		if (temp_opp->available) {
			/* go to the next node, before choosing prev */
			if (temp_opp->rate > *freq)
				break;
			else
				opp = temp_opp;
		}
	}
	if (!IS_ERR(opp))
		*freq = opp->rate;

	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);

/* List-dev Helpers */
static void _kfree_list_dev_rcu(struct rcu_head *head)
{
	struct device_list_opp *list_dev;

	list_dev = container_of(head, struct device_list_opp, rcu_head);
	kfree_rcu(list_dev, rcu_head);
}

static void _remove_list_dev(struct device_list_opp *list_dev,
			     struct device_opp *dev_opp)
{
	list_del(&list_dev->node);
	call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
		  _kfree_list_dev_rcu);
}

static struct device_list_opp *_add_list_dev(const struct device *dev,
					     struct device_opp *dev_opp)
{
	struct device_list_opp *list_dev;

	list_dev = kzalloc(sizeof(*list_dev), GFP_KERNEL);
	if (!list_dev)
		return NULL;

	/* Initialize list-dev */
	list_dev->dev = dev;
	list_add_rcu(&list_dev->node, &dev_opp->dev_list);

	return list_dev;
}

/**
 * _add_device_opp() - Find device OPP table or allocate a new one
 * @dev:	device for which we do this operation
 *
 * It tries to find an existing table first, if it couldn't find one, it
 * allocates a new OPP table and returns that.
 *
 * Return: valid device_opp pointer if success, else NULL.
 */
static struct device_opp *_add_device_opp(struct device *dev)
{
	struct device_opp *dev_opp;
	struct device_list_opp *list_dev;

	/* Check for existing list for 'dev' first */
	dev_opp = _find_device_opp(dev);
	if (!IS_ERR(dev_opp))
		return dev_opp;

	/*
	 * Allocate a new device OPP table. In the infrequent case where a new
	 * device is needed to be added, we pay this penalty.
	 */
	dev_opp = kzalloc(sizeof(*dev_opp), GFP_KERNEL);
	if (!dev_opp)
		return NULL;

	INIT_LIST_HEAD(&dev_opp->dev_list);

	list_dev = _add_list_dev(dev, dev_opp);
	if (!list_dev) {
		kfree(dev_opp);
		return NULL;
	}

	srcu_init_notifier_head(&dev_opp->srcu_head);
	INIT_LIST_HEAD(&dev_opp->opp_list);

	/* Secure the device list modification */
	list_add_rcu(&dev_opp->node, &dev_opp_list);
	return dev_opp;
}

/**
 * _kfree_device_rcu() - Free device_opp RCU handler
 * @head:	RCU head
 */
static void _kfree_device_rcu(struct rcu_head *head)
{
	struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);

	kfree_rcu(device_opp, rcu_head);
}

/**
 * _remove_device_opp() - Removes a device OPP table
 * @dev_opp: device OPP table to be removed.
 *
 * Removes/frees device OPP table it it doesn't contain any OPPs.
 */
static void _remove_device_opp(struct device_opp *dev_opp)
{
	struct device_list_opp *list_dev;

	if (!list_empty(&dev_opp->opp_list))
		return;

	list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,
				    node);

	_remove_list_dev(list_dev, dev_opp);

	/* dev_list must be empty now */
	WARN_ON(!list_empty(&dev_opp->dev_list));

	list_del_rcu(&dev_opp->node);
	call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
		  _kfree_device_rcu);
}

/**
 * _kfree_opp_rcu() - Free OPP RCU handler
 * @head:	RCU head
 */
static void _kfree_opp_rcu(struct rcu_head *head)
{
	struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);

	kfree_rcu(opp, rcu_head);
}

/**
 * _opp_remove()  - Remove an OPP from a table definition
 * @dev_opp:	points back to the device_opp struct this opp belongs to
 * @opp:	pointer to the OPP to remove
 * @notify:	OPP_EVENT_REMOVE notification should be sent or not
 *
 * This function removes an opp definition from the opp list.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * It is assumed that the caller holds required mutex for an RCU updater
 * strategy.
 */
static void _opp_remove(struct device_opp *dev_opp,
			struct dev_pm_opp *opp, bool notify)
{
	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	if (notify)
		srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
	list_del_rcu(&opp->node);
	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);

	_remove_device_opp(dev_opp);
}

/**
 * dev_pm_opp_remove()  - Remove an OPP from OPP list
 * @dev:	device for which we do this operation
 * @freq:	OPP to remove with matching 'freq'
 *
 * This function removes an opp from the opp list.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
void dev_pm_opp_remove(struct device *dev, unsigned long freq)
{
	struct dev_pm_opp *opp;
	struct device_opp *dev_opp;
	bool found = false;

	/* Hold our list modification lock here */
	mutex_lock(&dev_opp_list_lock);

	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp))
		goto unlock;

	list_for_each_entry(opp, &dev_opp->opp_list, node) {
		if (opp->rate == freq) {
			found = true;
			break;
		}
	}

	if (!found) {
		dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
			 __func__, freq);
		goto unlock;
	}

	_opp_remove(dev_opp, opp, true);
unlock:
	mutex_unlock(&dev_opp_list_lock);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove);

static struct dev_pm_opp *_allocate_opp(struct device *dev,
					struct device_opp **dev_opp)
{
	struct dev_pm_opp *opp;

	/* allocate new OPP node */
	opp = kzalloc(sizeof(*opp), GFP_KERNEL);
	if (!opp)
		return NULL;

	INIT_LIST_HEAD(&opp->node);

	*dev_opp = _add_device_opp(dev);
	if (!*dev_opp) {
		kfree(opp);
		return NULL;
	}

	return opp;
}

static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
		    struct device_opp *dev_opp)
{
	struct dev_pm_opp *opp;
	struct list_head *head = &dev_opp->opp_list;

	/*
	 * Insert new OPP in order of increasing frequency and discard if
	 * already present.
	 *
	 * Need to use &dev_opp->opp_list in the condition part of the 'for'
	 * loop, don't replace it with head otherwise it will become an infinite
	 * loop.
	 */
	list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
		if (new_opp->rate > opp->rate) {
			head = &opp->node;
			continue;
		}

		if (new_opp->rate < opp->rate)
			break;

		/* Duplicate OPPs */
		dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
			 __func__, opp->rate, opp->u_volt, opp->available,
			 new_opp->rate, new_opp->u_volt, new_opp->available);

		return opp->available && new_opp->u_volt == opp->u_volt ?
			0 : -EEXIST;
	}

	new_opp->dev_opp = dev_opp;
	list_add_rcu(&new_opp->node, head);

	return 0;
}

/**
 * _opp_add_dynamic() - Allocate a dynamic OPP.
 * @dev:	device for which we do this operation
 * @freq:	Frequency in Hz for this OPP
 * @u_volt:	Voltage in uVolts for this OPP
 * @dynamic:	Dynamically added OPPs.
 *
 * This function adds an opp definition to the opp list and returns status.
 * The opp is made available by default and it can be controlled using
 * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
 *
 * NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
 * freed by of_free_opp_table.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 */
static int _opp_add_dynamic(struct device *dev, unsigned long freq,
			    long u_volt, bool dynamic)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *new_opp;
	int ret;

	/* Hold our list modification lock here */
	mutex_lock(&dev_opp_list_lock);

	new_opp = _allocate_opp(dev, &dev_opp);
	if (!new_opp) {
		ret = -ENOMEM;
		goto unlock;
	}

	/* populate the opp table */
	new_opp->rate = freq;
	new_opp->u_volt = u_volt;
	new_opp->available = true;
	new_opp->dynamic = dynamic;

	ret = _opp_add(dev, new_opp, dev_opp);
	if (ret)
		goto free_opp;

	mutex_unlock(&dev_opp_list_lock);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
	return 0;

free_opp:
	_opp_remove(dev_opp, new_opp, false);
unlock:
	mutex_unlock(&dev_opp_list_lock);
	return ret;
}

/* TODO: Support multiple regulators */
static int opp_get_microvolt(struct dev_pm_opp *opp, struct device *dev)
{
	u32 microvolt[3] = {0};
	int count, ret;

	/* Missing property isn't a problem, but an invalid entry is */
	if (!of_find_property(opp->np, "opp-microvolt", NULL))
		return 0;

	count = of_property_count_u32_elems(opp->np, "opp-microvolt");
	if (count < 0) {
		dev_err(dev, "%s: Invalid opp-microvolt property (%d)\n",
			__func__, count);
		return count;
	}

	/* There can be one or three elements here */
	if (count != 1 && count != 3) {
		dev_err(dev, "%s: Invalid number of elements in opp-microvolt property (%d)\n",
			__func__, count);
		return -EINVAL;
	}

	ret = of_property_read_u32_array(opp->np, "opp-microvolt", microvolt,
					 count);
	if (ret) {
		dev_err(dev, "%s: error parsing opp-microvolt: %d\n", __func__,
			ret);
		return -EINVAL;
	}

	opp->u_volt = microvolt[0];
	opp->u_volt_min = microvolt[1];
	opp->u_volt_max = microvolt[2];

	return 0;
}

/**
 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 * @dev:	device for which we do this operation
 * @np:		device node
 *
 * This function adds an opp definition to the opp list and returns status. The
 * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 * removed by dev_pm_opp_remove.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -EINVAL	Failed parsing the OPP node
 */
static int _opp_add_static_v2(struct device *dev, struct device_node *np)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *new_opp;
	u64 rate;
	u32 val;
	int ret;

	/* Hold our list modification lock here */
	mutex_lock(&dev_opp_list_lock);

	new_opp = _allocate_opp(dev, &dev_opp);
	if (!new_opp) {
		ret = -ENOMEM;
		goto unlock;
	}

	ret = of_property_read_u64(np, "opp-hz", &rate);
	if (ret < 0) {
		dev_err(dev, "%s: opp-hz not found\n", __func__);
		goto free_opp;
	}

	/*
	 * Rate is defined as an unsigned long in clk API, and so casting
	 * explicitly to its type. Must be fixed once rate is 64 bit
	 * guaranteed in clk API.
	 */
	new_opp->rate = (unsigned long)rate;
	new_opp->turbo = of_property_read_bool(np, "turbo-mode");

	new_opp->np = np;
	new_opp->dynamic = false;
	new_opp->available = true;

	if (!of_property_read_u32(np, "clock-latency-ns", &val))
		new_opp->clock_latency_ns = val;

	ret = opp_get_microvolt(new_opp, dev);
	if (ret)
		goto free_opp;

	if (!of_property_read_u32(new_opp->np, "opp-microamp", &val))
		new_opp->u_amp = val;

	ret = _opp_add(dev, new_opp, dev_opp);
	if (ret)
		goto free_opp;

	/* OPP to select on device suspend */
	if (of_property_read_bool(np, "opp-suspend")) {
		if (dev_opp->suspend_opp)
			dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
				 __func__, dev_opp->suspend_opp->rate,
				 new_opp->rate);
		else
			dev_opp->suspend_opp = new_opp;
	}

	if (new_opp->clock_latency_ns > dev_opp->clock_latency_ns_max)
		dev_opp->clock_latency_ns_max = new_opp->clock_latency_ns;

	mutex_unlock(&dev_opp_list_lock);

	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
		 __func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
		 new_opp->u_volt_min, new_opp->u_volt_max,
		 new_opp->clock_latency_ns);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
	return 0;

free_opp:
	_opp_remove(dev_opp, new_opp, false);
unlock:
	mutex_unlock(&dev_opp_list_lock);
	return ret;
}

/**
 * dev_pm_opp_add()  - Add an OPP table from a table definitions
 * @dev:	device for which we do this operation
 * @freq:	Frequency in Hz for this OPP
 * @u_volt:	Voltage in uVolts for this OPP
 *
 * This function adds an opp definition to the opp list and returns status.
 * The opp is made available by default and it can be controlled using
 * dev_pm_opp_enable/disable functions.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 */
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
	return _opp_add_dynamic(dev, freq, u_volt, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add);

/**
 * _opp_set_availability() - helper to set the availability of an opp
 * @dev:		device for which we do this operation
 * @freq:		OPP frequency to modify availability
 * @availability_req:	availability status requested for this opp
 *
 * Set the availability of an OPP with an RCU operation, opp_{enable,disable}
 * share a common logic which is isolated here.
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks to
 * keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex locking or synchronize_rcu() blocking calls cannot be used.
 */
static int _opp_set_availability(struct device *dev, unsigned long freq,
				 bool availability_req)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
	int r = 0;

	/* keep the node allocated */
	new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
	if (!new_opp)
		return -ENOMEM;

	mutex_lock(&dev_opp_list_lock);

	/* Find the device_opp */
	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp)) {
		r = PTR_ERR(dev_opp);
		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
		goto unlock;
	}

	/* Do we have the frequency? */
	list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) {
		if (tmp_opp->rate == freq) {
			opp = tmp_opp;
			break;
		}
	}
	if (IS_ERR(opp)) {
		r = PTR_ERR(opp);
		goto unlock;
	}

	/* Is update really needed? */
	if (opp->available == availability_req)
		goto unlock;
	/* copy the old data over */
	*new_opp = *opp;

	/* plug in new node */
	new_opp->available = availability_req;

	list_replace_rcu(&opp->node, &new_opp->node);
	mutex_unlock(&dev_opp_list_lock);
	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);

	/* Notify the change of the OPP availability */
	if (availability_req)
		srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ENABLE,
					 new_opp);
	else
		srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_DISABLE,
					 new_opp);

	return 0;

unlock:
	mutex_unlock(&dev_opp_list_lock);
	kfree(new_opp);
	return r;
}

/**
 * dev_pm_opp_enable() - Enable a specific OPP
 * @dev:	device for which we do this operation
 * @freq:	OPP frequency to enable
 *
 * Enables a provided opp. If the operation is valid, this returns 0, else the
 * corresponding error value. It is meant to be used for users an OPP available
 * after being temporarily made unavailable with dev_pm_opp_disable.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function indirectly uses RCU and mutex locks to keep the
 * integrity of the internal data structures. Callers should ensure that
 * this function is *NOT* called under RCU protection or in contexts where
 * mutex locking or synchronize_rcu() blocking calls cannot be used.
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 */
int dev_pm_opp_enable(struct device *dev, unsigned long freq)
{
	return _opp_set_availability(dev, freq, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_enable);

/**
 * dev_pm_opp_disable() - Disable a specific OPP
 * @dev:	device for which we do this operation
 * @freq:	OPP frequency to disable
 *
 * Disables a provided opp. If the operation is valid, this returns
 * 0, else the corresponding error value. It is meant to be a temporary
 * control by users to make this OPP not available until the circumstances are
 * right to make it available again (with a call to dev_pm_opp_enable).
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function indirectly uses RCU and mutex locks to keep the
 * integrity of the internal data structures. Callers should ensure that
 * this function is *NOT* called under RCU protection or in contexts where
 * mutex locking or synchronize_rcu() blocking calls cannot be used.
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 */
int dev_pm_opp_disable(struct device *dev, unsigned long freq)
{
	return _opp_set_availability(dev, freq, false);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_disable);

/**
 * dev_pm_opp_get_notifier() - find notifier_head of the device with opp
 * @dev:	device pointer used to lookup device OPPs.
 *
 * Return: pointer to  notifier head if found, otherwise -ENODEV or
 * -EINVAL based on type of error casted as pointer. value must be checked
 *  with IS_ERR to determine valid pointer or error result.
 *
 * Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
 * protected pointer. The reason for the same is that the opp pointer which is
 * returned will remain valid for use with opp_get_{voltage, freq} only while
 * under the locked area. The pointer returned must be used prior to unlocking
 * with rcu_read_unlock() to maintain the integrity of the pointer.
 */
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
{
	struct device_opp *dev_opp = _find_device_opp(dev);

	if (IS_ERR(dev_opp))
		return ERR_CAST(dev_opp); /* matching type */

	return &dev_opp->srcu_head;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);

#ifdef CONFIG_OF
/**
 * of_free_opp_table() - Free OPP table entries created from static DT entries
 * @dev:	device pointer used to lookup device OPPs.
 *
 * Free OPPs created using static entries present in DT.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function indirectly uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
void of_free_opp_table(struct device *dev)
{
	struct device_opp *dev_opp;
	struct dev_pm_opp *opp, *tmp;

	/* Hold our list modification lock here */
	mutex_lock(&dev_opp_list_lock);

	/* Check for existing list for 'dev' */
	dev_opp = _find_device_opp(dev);
	if (IS_ERR(dev_opp)) {
		int error = PTR_ERR(dev_opp);

		if (error != -ENODEV)
			WARN(1, "%s: dev_opp: %d\n",
			     IS_ERR_OR_NULL(dev) ?
					"Invalid device" : dev_name(dev),
			     error);
		goto unlock;
	}

	/* Find if dev_opp manages a single device */
	if (list_is_singular(&dev_opp->dev_list)) {
		/* Free static OPPs */
		list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
			if (!opp->dynamic)
				_opp_remove(dev_opp, opp, true);
		}
	} else {
		_remove_list_dev(_find_list_dev(dev, dev_opp), dev_opp);
	}

unlock:
	mutex_unlock(&dev_opp_list_lock);
}
EXPORT_SYMBOL_GPL(of_free_opp_table);

void of_cpumask_free_opp_table(cpumask_var_t cpumask)
{
	struct device *cpu_dev;
	int cpu;

	WARN_ON(cpumask_empty(cpumask));

	for_each_cpu(cpu, cpumask) {
		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_err("%s: failed to get cpu%d device\n", __func__,
			       cpu);
			continue;
		}

		of_free_opp_table(cpu_dev);
	}
}
EXPORT_SYMBOL_GPL(of_cpumask_free_opp_table);

/* Returns opp descriptor node from its phandle. Caller must do of_node_put() */
static struct device_node *
_of_get_opp_desc_node_from_prop(struct device *dev, const struct property *prop)
{
	struct device_node *opp_np;

	opp_np = of_find_node_by_phandle(be32_to_cpup(prop->value));
	if (!opp_np) {
		dev_err(dev, "%s: Prop: %s contains invalid opp desc phandle\n",
			__func__, prop->name);
		return ERR_PTR(-EINVAL);
	}

	return opp_np;
}

/* Returns opp descriptor node for a device. Caller must do of_node_put() */
static struct device_node *_of_get_opp_desc_node(struct device *dev)
{
	const struct property *prop;

	prop = of_find_property(dev->of_node, "operating-points-v2", NULL);
	if (!prop)
		return ERR_PTR(-ENODEV);
	if (!prop->value)
		return ERR_PTR(-ENODATA);

	/*
	 * TODO: Support for multiple OPP tables.
	 *
	 * There should be only ONE phandle present in "operating-points-v2"
	 * property.
	 */
	if (prop->length != sizeof(__be32)) {
		dev_err(dev, "%s: Invalid opp desc phandle\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	return _of_get_opp_desc_node_from_prop(dev, prop);
}

/* Initializes OPP tables based on new bindings */
static int _of_init_opp_table_v2(struct device *dev,
				 const struct property *prop)
{
	struct device_node *opp_np, *np;
	struct device_opp *dev_opp;
	int ret = 0, count = 0;

	if (!prop->value)
		return -ENODATA;

	/* Get opp node */
	opp_np = _of_get_opp_desc_node_from_prop(dev, prop);
	if (IS_ERR(opp_np))
		return PTR_ERR(opp_np);

	dev_opp = _managed_opp(opp_np);
	if (dev_opp) {
		/* OPPs are already managed */
		if (!_add_list_dev(dev, dev_opp))
			ret = -ENOMEM;
		goto put_opp_np;
	}

	/* We have opp-list node now, iterate over it and add OPPs */
	for_each_available_child_of_node(opp_np, np) {
		count++;

		ret = _opp_add_static_v2(dev, np);
		if (ret) {
			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
				ret);
			goto free_table;
		}
	}

	/* There should be one of more OPP defined */
	if (WARN_ON(!count)) {
		ret = -ENOENT;
		goto put_opp_np;
	}

	dev_opp = _find_device_opp(dev);
	if (WARN_ON(IS_ERR(dev_opp))) {
		ret = PTR_ERR(dev_opp);
		goto free_table;
	}

	dev_opp->np = opp_np;
	dev_opp->shared_opp = of_property_read_bool(opp_np, "opp-shared");

	of_node_put(opp_np);
	return 0;

free_table:
	of_free_opp_table(dev);
put_opp_np:
	of_node_put(opp_np);

	return ret;
}

/* Initializes OPP tables based on old-deprecated bindings */
static int _of_init_opp_table_v1(struct device *dev)
{
	const struct property *prop;
	const __be32 *val;
	int nr;

	prop = of_find_property(dev->of_node, "operating-points", NULL);
	if (!prop)
		return -ENODEV;
	if (!prop->value)
		return -ENODATA;

	/*
	 * Each OPP is a set of tuples consisting of frequency and
	 * voltage like <freq-kHz vol-uV>.
	 */
	nr = prop->length / sizeof(u32);
	if (nr % 2) {
		dev_err(dev, "%s: Invalid OPP list\n", __func__);
		return -EINVAL;
	}

	val = prop->value;
	while (nr) {
		unsigned long freq = be32_to_cpup(val++) * 1000;
		unsigned long volt = be32_to_cpup(val++);

		if (_opp_add_dynamic(dev, freq, volt, false))
			dev_warn(dev, "%s: Failed to add OPP %ld\n",
				 __func__, freq);
		nr -= 2;
	}

	return 0;
}

/**
 * of_init_opp_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup device OPPs.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * Locking: The internal device_opp and opp structures are RCU protected.
 * Hence this function indirectly uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int of_init_opp_table(struct device *dev)
{
	const struct property *prop;

	/*
	 * OPPs have two version of bindings now. The older one is deprecated,
	 * try for the new binding first.
	 */
	prop = of_find_property(dev->of_node, "operating-points-v2", NULL);
	if (!prop) {
		/*
		 * Try old-deprecated bindings for backward compatibility with
		 * older dtbs.
		 */
		return _of_init_opp_table_v1(dev);
	}

	return _of_init_opp_table_v2(dev, prop);
}
EXPORT_SYMBOL_GPL(of_init_opp_table);

int of_cpumask_init_opp_table(cpumask_var_t cpumask)
{
	struct device *cpu_dev;
	int cpu, ret = 0;

	WARN_ON(cpumask_empty(cpumask));

	for_each_cpu(cpu, cpumask) {
		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_err("%s: failed to get cpu%d device\n", __func__,
			       cpu);
			continue;
		}

		ret = of_init_opp_table(cpu_dev);
		if (ret) {
			pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
			       __func__, cpu, ret);

			/* Free all other OPPs */
			of_cpumask_free_opp_table(cpumask);
			break;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(of_cpumask_init_opp_table);

/* Required only for V1 bindings, as v2 can manage it from DT itself */
int set_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
{
	struct device_list_opp *list_dev;
	struct device_opp *dev_opp;
	struct device *dev;
	int cpu, ret = 0;

	rcu_read_lock();

	dev_opp = _find_device_opp(cpu_dev);
	if (IS_ERR(dev_opp)) {
		ret = -EINVAL;
		goto out_rcu_read_unlock;
	}

	for_each_cpu(cpu, cpumask) {
		if (cpu == cpu_dev->id)
			continue;

		dev = get_cpu_device(cpu);
		if (!dev) {
			dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
				__func__, cpu);
			continue;
		}

		list_dev = _add_list_dev(dev, dev_opp);
		if (!list_dev) {
			dev_err(dev, "%s: failed to add list-dev for cpu%d device\n",
				__func__, cpu);
			continue;
		}
	}
out_rcu_read_unlock:
	rcu_read_unlock();

	return 0;
}
EXPORT_SYMBOL_GPL(set_cpus_sharing_opps);

/*
 * Works only for OPP v2 bindings.
 *
 * cpumask should be already set to mask of cpu_dev->id.
 * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 */
int of_get_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
{
	struct device_node *np, *tmp_np;
	struct device *tcpu_dev;
	int cpu, ret = 0;

	/* Get OPP descriptor node */
	np = _of_get_opp_desc_node(cpu_dev);
	if (IS_ERR(np)) {
		dev_dbg(cpu_dev, "%s: Couldn't find opp node: %ld\n", __func__,
			PTR_ERR(np));
		return -ENOENT;
	}

	/* OPPs are shared ? */
	if (!of_property_read_bool(np, "opp-shared"))
		goto put_cpu_node;

	for_each_possible_cpu(cpu) {
		if (cpu == cpu_dev->id)
			continue;

		tcpu_dev = get_cpu_device(cpu);
		if (!tcpu_dev) {
			dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
				__func__, cpu);
			ret = -ENODEV;
			goto put_cpu_node;
		}

		/* Get OPP descriptor node */
		tmp_np = _of_get_opp_desc_node(tcpu_dev);
		if (IS_ERR(tmp_np)) {
			dev_err(tcpu_dev, "%s: Couldn't find opp node: %ld\n",
				__func__, PTR_ERR(tmp_np));
			ret = PTR_ERR(tmp_np);
			goto put_cpu_node;
		}

		/* CPUs are sharing opp node */
		if (np == tmp_np)
			cpumask_set_cpu(cpu, cpumask);

		of_node_put(tmp_np);
	}

put_cpu_node:
	of_node_put(np);
	return ret;
}
EXPORT_SYMBOL_GPL(of_get_cpus_sharing_opps);
#endif