aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/mach-omap2/clockdomain.c
blob: a1555627ad973048ea36f9dca72baa235dae52a3 (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
/*
 * OMAP2/3/4 clockdomain framework functions
 *
 * Copyright (C) 2008-2011 Texas Instruments, Inc.
 * Copyright (C) 2008-2011 Nokia Corporation
 *
 * Written by Paul Walmsley and Jouni Högander
 * Added OMAP4 specific support by Abhijit Pagare <abhijitpagare@ti.com>
 *
 * 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.
 */
#undef DEBUG

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/limits.h>
#include <linux/err.h>

#include <linux/io.h>

#include <linux/bitops.h>

#include <plat/clock.h>
#include "clockdomain.h"

/* clkdm_list contains all registered struct clockdomains */
static LIST_HEAD(clkdm_list);

/* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
static struct clkdm_autodep *autodeps;

static struct clkdm_ops *arch_clkdm;

/* Private functions */

static struct clockdomain *_clkdm_lookup(const char *name)
{
	struct clockdomain *clkdm, *temp_clkdm;

	if (!name)
		return NULL;

	clkdm = NULL;

	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
		if (!strcmp(name, temp_clkdm->name)) {
			clkdm = temp_clkdm;
			break;
		}
	}

	return clkdm;
}

/**
 * _clkdm_register - register a clockdomain
 * @clkdm: struct clockdomain * to register
 *
 * Adds a clockdomain to the internal clockdomain list.
 * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
 * already registered by the provided name, or 0 upon success.
 */
static int _clkdm_register(struct clockdomain *clkdm)
{
	struct powerdomain *pwrdm;

	if (!clkdm || !clkdm->name)
		return -EINVAL;

	pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
	if (!pwrdm) {
		pr_err("clockdomain: %s: powerdomain %s does not exist\n",
			clkdm->name, clkdm->pwrdm.name);
		return -EINVAL;
	}
	clkdm->pwrdm.ptr = pwrdm;

	/* Verify that the clockdomain is not already registered */
	if (_clkdm_lookup(clkdm->name))
		return -EEXIST;

	list_add(&clkdm->node, &clkdm_list);

	pwrdm_add_clkdm(pwrdm, clkdm);

	spin_lock_init(&clkdm->lock);

	pr_debug("clockdomain: registered %s\n", clkdm->name);

	return 0;
}

/* _clkdm_deps_lookup - look up the specified clockdomain in a clkdm list */
static struct clkdm_dep *_clkdm_deps_lookup(struct clockdomain *clkdm,
					    struct clkdm_dep *deps)
{
	struct clkdm_dep *cd;

	if (!clkdm || !deps)
		return ERR_PTR(-EINVAL);

	for (cd = deps; cd->clkdm_name; cd++) {
		if (!cd->clkdm && cd->clkdm_name)
			cd->clkdm = _clkdm_lookup(cd->clkdm_name);

		if (cd->clkdm == clkdm)
			break;
	}

	if (!cd->clkdm_name)
		return ERR_PTR(-ENOENT);

	return cd;
}

/*
 * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
 * @autodep: struct clkdm_autodep * to resolve
 *
 * Resolve autodep clockdomain names to clockdomain pointers via
 * clkdm_lookup() and store the pointers in the autodep structure.  An
 * "autodep" is a clockdomain sleep/wakeup dependency that is
 * automatically added and removed whenever clocks in the associated
 * clockdomain are enabled or disabled (respectively) when the
 * clockdomain is in hardware-supervised mode.	Meant to be called
 * once at clockdomain layer initialization, since these should remain
 * fixed for a particular architecture.  No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
static void _autodep_lookup(struct clkdm_autodep *autodep)
{
	struct clockdomain *clkdm;

	if (!autodep)
		return;

	clkdm = clkdm_lookup(autodep->clkdm.name);
	if (!clkdm) {
		pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
			 autodep->clkdm.name);
		clkdm = ERR_PTR(-ENOENT);
	}
	autodep->clkdm.ptr = clkdm;
}

/*
 * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
 * @clkdm: struct clockdomain *
 *
 * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is enabled.	No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
void _clkdm_add_autodeps(struct clockdomain *clkdm)
{
	struct clkdm_autodep *autodep;

	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
		return;

	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
		if (IS_ERR(autodep->clkdm.ptr))
			continue;

		pr_debug("clockdomain: %s: adding %s sleepdep/wkdep\n",
			 clkdm->name, autodep->clkdm.ptr->name);

		clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
		clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
	}
}

/*
 * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 * @clkdm: struct clockdomain *
 *
 * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
void _clkdm_del_autodeps(struct clockdomain *clkdm)
{
	struct clkdm_autodep *autodep;

	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
		return;

	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
		if (IS_ERR(autodep->clkdm.ptr))
			continue;

		pr_debug("clockdomain: %s: removing %s sleepdep/wkdep\n",
			 clkdm->name, autodep->clkdm.ptr->name);

		clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
		clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
	}
}

/**
 * _resolve_clkdm_deps() - resolve clkdm_names in @clkdm_deps to clkdms
 * @clkdm: clockdomain that we are resolving dependencies for
 * @clkdm_deps: ptr to array of struct clkdm_deps to resolve
 *
 * Iterates through @clkdm_deps, looking up the struct clockdomain named by
 * clkdm_name and storing the clockdomain pointer in the struct clkdm_dep.
 * No return value.
 */
static void _resolve_clkdm_deps(struct clockdomain *clkdm,
				struct clkdm_dep *clkdm_deps)
{
	struct clkdm_dep *cd;

	for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
		if (cd->clkdm)
			continue;
		cd->clkdm = _clkdm_lookup(cd->clkdm_name);

		WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
		     clkdm->name, cd->clkdm_name);
	}
}

/* Public functions */

/**
 * clkdm_register_platform_funcs - register clockdomain implementation fns
 * @co: func pointers for arch specific implementations
 *
 * Register the list of function pointers used to implement the
 * clockdomain functions on different OMAP SoCs.  Should be called
 * before any other clkdm_register*() function.  Returns -EINVAL if
 * @co is null, -EEXIST if platform functions have already been
 * registered, or 0 upon success.
 */
int clkdm_register_platform_funcs(struct clkdm_ops *co)
{
	if (!co)
		return -EINVAL;

	if (arch_clkdm)
		return -EEXIST;

	arch_clkdm = co;

	return 0;
};

/**
 * clkdm_register_clkdms - register SoC clockdomains
 * @cs: pointer to an array of struct clockdomain to register
 *
 * Register the clockdomains available on a particular OMAP SoC.  Must
 * be called after clkdm_register_platform_funcs().  May be called
 * multiple times.  Returns -EACCES if called before
 * clkdm_register_platform_funcs(); -EINVAL if the argument @cs is
 * null; or 0 upon success.
 */
int clkdm_register_clkdms(struct clockdomain **cs)
{
	struct clockdomain **c = NULL;

	if (!arch_clkdm)
		return -EACCES;

	if (!cs)
		return -EINVAL;

	for (c = cs; *c; c++)
		_clkdm_register(*c);

	return 0;
}

/**
 * clkdm_register_autodeps - register autodeps (if required)
 * @ia: pointer to a static array of struct clkdm_autodep to register
 *
 * Register clockdomain "automatic dependencies."  These are
 * clockdomain wakeup and sleep dependencies that are automatically
 * added whenever the first clock inside a clockdomain is enabled, and
 * removed whenever the last clock inside a clockdomain is disabled.
 * These are currently only used on OMAP3 devices, and are deprecated,
 * since they waste energy.  However, until the OMAP2/3 IP block
 * enable/disable sequence can be converted to match the OMAP4
 * sequence, they are needed.
 *
 * Must be called only after all of the SoC clockdomains are
 * registered, since the function will resolve autodep clockdomain
 * names into clockdomain pointers.
 *
 * The struct clkdm_autodep @ia array must be static, as this function
 * does not copy the array elements.
 *
 * Returns -EACCES if called before any clockdomains have been
 * registered, -EINVAL if called with a null @ia argument, -EEXIST if
 * autodeps have already been registered, or 0 upon success.
 */
int clkdm_register_autodeps(struct clkdm_autodep *ia)
{
	struct clkdm_autodep *a = NULL;

	if (list_empty(&clkdm_list))
		return -EACCES;

	if (!ia)
		return -EINVAL;

	if (autodeps)
		return -EEXIST;

	autodeps = ia;
	for (a = autodeps; a->clkdm.ptr; a++)
		_autodep_lookup(a);

	return 0;
}

/**
 * clkdm_complete_init - set up the clockdomain layer
 *
 * Put all clockdomains into software-supervised mode; PM code should
 * later enable hardware-supervised mode as appropriate.  Must be
 * called after clkdm_register_clkdms().  Returns -EACCES if called
 * before clkdm_register_clkdms(), or 0 upon success.
 */
int clkdm_complete_init(void)
{
	struct clockdomain *clkdm;

	if (list_empty(&clkdm_list))
		return -EACCES;

	list_for_each_entry(clkdm, &clkdm_list, node) {
		if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
			clkdm_wakeup(clkdm);
		else if (clkdm->flags & CLKDM_CAN_DISABLE_AUTO)
			clkdm_deny_idle(clkdm);

		_resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
		clkdm_clear_all_wkdeps(clkdm);

		_resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
		clkdm_clear_all_sleepdeps(clkdm);
	}

	return 0;
}

/**
 * clkdm_lookup - look up a clockdomain by name, return a pointer
 * @name: name of clockdomain
 *
 * Find a registered clockdomain by its name @name.  Returns a pointer
 * to the struct clockdomain if found, or NULL otherwise.
 */
struct clockdomain *clkdm_lookup(const char *name)
{
	struct clockdomain *clkdm, *temp_clkdm;

	if (!name)
		return NULL;

	clkdm = NULL;

	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
		if (!strcmp(name, temp_clkdm->name)) {
			clkdm = temp_clkdm;
			break;
		}
	}

	return clkdm;
}

/**
 * clkdm_for_each - call function on each registered clockdomain
 * @fn: callback function *
 *
 * Call the supplied function @fn for each registered clockdomain.
 * The callback function @fn can return anything but 0 to bail
 * out early from the iterator.  The callback function is called with
 * the clkdm_mutex held, so no clockdomain structure manipulation
 * functions should be called from the callback, although hardware
 * clockdomain control functions are fine.  Returns the last return
 * value of the callback function, which should be 0 for success or
 * anything else to indicate failure; or -EINVAL if the function pointer
 * is null.
 */
int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
			void *user)
{
	struct clockdomain *clkdm;
	int ret = 0;

	if (!fn)
		return -EINVAL;

	list_for_each_entry(clkdm, &clkdm_list, node) {
		ret = (*fn)(clkdm, user);
		if (ret)
			break;
	}

	return ret;
}


/**
 * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 * @clkdm: struct clockdomain *
 *
 * Return a pointer to the struct powerdomain that the specified clockdomain
 * @clkdm exists in, or returns NULL if @clkdm is NULL.
 */
struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
{
	if (!clkdm)
		return NULL;

	return clkdm->pwrdm.ptr;
}


/* Hardware clockdomain control */

/**
 * clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1
 * @clkdm1: wake this struct clockdomain * up (dependent)
 * @clkdm2: when this struct clockdomain * wakes up (source)
 *
 * When the clockdomain represented by @clkdm2 wakes up, wake up
 * @clkdm1. Implemented in hardware on the OMAP, this feature is
 * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
 * Returns -EINVAL if presented with invalid clockdomain pointers,
 * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
 * success.
 */
int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	if (atomic_inc_return(&cd->wkdep_usecount) == 1) {
		pr_debug("clockdomain: hardware will wake up %s when %s wakes up\n",
			 clkdm1->name, clkdm2->name);

		ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
	}

	return ret;
}

/**
 * clkdm_del_wkdep - remove a wakeup dependency from clkdm2 to clkdm1
 * @clkdm1: wake this struct clockdomain * up (dependent)
 * @clkdm2: when this struct clockdomain * wakes up (source)
 *
 * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
 * wakes up.  Returns -EINVAL if presented with invalid clockdomain
 * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
 * 0 upon success.
 */
int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	if (atomic_dec_return(&cd->wkdep_usecount) == 0) {
		pr_debug("clockdomain: hardware will no longer wake up %s after %s wakes up\n",
			 clkdm1->name, clkdm2->name);

		ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
	}

	return ret;
}

/**
 * clkdm_read_wkdep - read wakeup dependency state from clkdm2 to clkdm1
 * @clkdm1: wake this struct clockdomain * up (dependent)
 * @clkdm2: when this struct clockdomain * wakes up (source)
 *
 * Return 1 if a hardware wakeup dependency exists wherein @clkdm1 will be
 * awoken when @clkdm2 wakes up; 0 if dependency is not set; -EINVAL
 * if either clockdomain pointer is invalid; or -ENOENT if the hardware
 * is incapable.
 *
 * REVISIT: Currently this function only represents software-controllable
 * wakeup dependencies.  Wakeup dependencies fixed in hardware are not
 * yet handled here.
 */
int clkdm_read_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	/* XXX It's faster to return the atomic wkdep_usecount */
	return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
}

/**
 * clkdm_clear_all_wkdeps - remove all wakeup dependencies from target clkdm
 * @clkdm: struct clockdomain * to remove all wakeup dependencies from
 *
 * Remove all inter-clockdomain wakeup dependencies that could cause
 * @clkdm to wake.  Intended to be used during boot to initialize the
 * PRCM to a known state, after all clockdomains are put into swsup idle
 * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 * 0 upon success.
 */
int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
{
	if (!clkdm)
		return -EINVAL;

	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
		return -EINVAL;

	return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
}

/**
 * clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1
 * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 * @clkdm2: when this struct clockdomain * is active (source)
 *
 * Prevent @clkdm1 from automatically going inactive (and then to
 * retention or off) if @clkdm2 is active.  Returns -EINVAL if
 * presented with invalid clockdomain pointers or called on a machine
 * that does not support software-configurable hardware sleep
 * dependencies, -ENOENT if the specified dependency cannot be set in
 * hardware, or 0 upon success.
 */
int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	if (atomic_inc_return(&cd->sleepdep_usecount) == 1) {
		pr_debug("clockdomain: will prevent %s from sleeping if %s is active\n",
			 clkdm1->name, clkdm2->name);

		ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
	}

	return ret;
}

/**
 * clkdm_del_sleepdep - remove a sleep dependency from clkdm2 to clkdm1
 * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 * @clkdm2: when this struct clockdomain * is active (source)
 *
 * Allow @clkdm1 to automatically go inactive (and then to retention or
 * off), independent of the activity state of @clkdm2.  Returns -EINVAL
 * if presented with invalid clockdomain pointers or called on a machine
 * that does not support software-configurable hardware sleep dependencies,
 * -ENOENT if the specified dependency cannot be cleared in hardware, or
 * 0 upon success.
 */
int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	if (atomic_dec_return(&cd->sleepdep_usecount) == 0) {
		pr_debug("clockdomain: will no longer prevent %s from sleeping if %s is active\n",
			 clkdm1->name, clkdm2->name);

		ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
	}

	return ret;
}

/**
 * clkdm_read_sleepdep - read sleep dependency state from clkdm2 to clkdm1
 * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 * @clkdm2: when this struct clockdomain * is active (source)
 *
 * Return 1 if a hardware sleep dependency exists wherein @clkdm1 will
 * not be allowed to automatically go inactive if @clkdm2 is active;
 * 0 if @clkdm1's automatic power state inactivity transition is independent
 * of @clkdm2's; -EINVAL if either clockdomain pointer is invalid or called
 * on a machine that does not support software-configurable hardware sleep
 * dependencies; or -ENOENT if the hardware is incapable.
 *
 * REVISIT: Currently this function only represents software-controllable
 * sleep dependencies.	Sleep dependencies fixed in hardware are not
 * yet handled here.
 */
int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
	struct clkdm_dep *cd;
	int ret = 0;

	if (!clkdm1 || !clkdm2)
		return -EINVAL;

	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
	if (IS_ERR(cd))
		ret = PTR_ERR(cd);

	if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
		ret = -EINVAL;

	if (ret) {
		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
			 clkdm1->name, clkdm2->name);
		return ret;
	}

	/* XXX It's faster to return the atomic sleepdep_usecount */
	return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
}

/**
 * clkdm_clear_all_sleepdeps - remove all sleep dependencies from target clkdm
 * @clkdm: struct clockdomain * to remove all sleep dependencies from
 *
 * Remove all inter-clockdomain sleep dependencies that could prevent
 * @clkdm from idling.  Intended to be used during boot to initialize the
 * PRCM to a known state, after all clockdomains are put into swsup idle
 * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 * 0 upon success.
 */
int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
{
	if (!clkdm)
		return -EINVAL;

	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
		return -EINVAL;

	return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
}

/**
 * clkdm_sleep - force clockdomain sleep transition
 * @clkdm: struct clockdomain *
 *
 * Instruct the CM to force a sleep transition on the specified
 * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if
 * clockdomain does not support software-initiated sleep; 0 upon
 * success.
 */
int clkdm_sleep(struct clockdomain *clkdm)
{
	int ret;
	unsigned long flags;

	if (!clkdm)
		return -EINVAL;

	if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
		pr_debug("clockdomain: %s does not support forcing sleep via software\n",
			 clkdm->name);
		return -EINVAL;
	}

	if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
		return -EINVAL;

	pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);

	spin_lock_irqsave(&clkdm->lock, flags);
	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
	ret = arch_clkdm->clkdm_sleep(clkdm);
	spin_unlock_irqrestore(&clkdm->lock, flags);
	return ret;
}

/**
 * clkdm_wakeup - force clockdomain wakeup transition
 * @clkdm: struct clockdomain *
 *
 * Instruct the CM to force a wakeup transition on the specified
 * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if the
 * clockdomain does not support software-controlled wakeup; 0 upon
 * success.
 */
int clkdm_wakeup(struct clockdomain *clkdm)
{
	int ret;
	unsigned long flags;

	if (!clkdm)
		return -EINVAL;

	if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
		pr_debug("clockdomain: %s does not support forcing wakeup via software\n",
			 clkdm->name);
		return -EINVAL;
	}

	if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
		return -EINVAL;

	pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);

	spin_lock_irqsave(&clkdm->lock, flags);
	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
	ret = arch_clkdm->clkdm_wakeup(clkdm);
	ret |= pwrdm_state_switch(clkdm->pwrdm.ptr);
	spin_unlock_irqrestore(&clkdm->lock, flags);
	return ret;
}

/**
 * clkdm_allow_idle - enable hwsup idle transitions for clkdm
 * @clkdm: struct clockdomain *
 *
 * Allow the hardware to automatically switch the clockdomain @clkdm into
 * active or idle states, as needed by downstream clocks.  If the
 * clockdomain has any downstream clocks enabled in the clock
 * framework, wkdep/sleepdep autodependencies are added; this is so
 * device drivers can read and write to the device.  No return value.
 */
void clkdm_allow_idle(struct clockdomain *clkdm)
{
	unsigned long flags;

	if (!clkdm)
		return;

	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
		pr_debug("clock: %s: automatic idle transitions cannot be enabled\n",
			 clkdm->name);
		return;
	}

	if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
		return;

	pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
		 clkdm->name);

	spin_lock_irqsave(&clkdm->lock, flags);
	clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
	arch_clkdm->clkdm_allow_idle(clkdm);
	pwrdm_state_switch(clkdm->pwrdm.ptr);
	spin_unlock_irqrestore(&clkdm->lock, flags);
}

/**
 * clkdm_deny_idle - disable hwsup idle transitions for clkdm
 * @clkdm: struct clockdomain *
 *
 * Prevent the hardware from automatically switching the clockdomain
 * @clkdm into inactive or idle states.  If the clockdomain has
 * downstream clocks enabled in the clock framework, wkdep/sleepdep
 * autodependencies are removed.  No return value.
 */
void clkdm_deny_idle(struct clockdomain *clkdm)
{
	unsigned long flags;

	if (!clkdm)
		return;

	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
		pr_debug("clockdomain: %s: automatic idle transitions cannot be disabled\n",
			 clkdm->name);
		return;
	}

	if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
		return;

	pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
		 clkdm->name);

	spin_lock_irqsave(&clkdm->lock, flags);
	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
	arch_clkdm->clkdm_deny_idle(clkdm);
	pwrdm_state_switch(clkdm->pwrdm.ptr);
	spin_unlock_irqrestore(&clkdm->lock, flags);
}

/**
 * clkdm_in_hwsup - is clockdomain @clkdm have hardware-supervised idle enabled?
 * @clkdm: struct clockdomain *
 *
 * Returns true if clockdomain @clkdm currently has
 * hardware-supervised idle enabled, or false if it does not or if
 * @clkdm is NULL.  It is only valid to call this function after
 * clkdm_init() has been called.  This function does not actually read
 * bits from the hardware; it instead tests an in-memory flag that is
 * changed whenever the clockdomain code changes the auto-idle mode.
 */
bool clkdm_in_hwsup(struct clockdomain *clkdm)
{
	bool ret;
	unsigned long flags;

	if (!clkdm)
		return false;

	spin_lock_irqsave(&clkdm->lock, flags);
	ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
	spin_unlock_irqrestore(&clkdm->lock, flags);

	return ret;
}

/* Clockdomain-to-clock/hwmod framework interface code */

static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
{
	unsigned long flags;

	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
		return -EINVAL;

	/*
	 * For arch's with no autodeps, clkcm_clk_enable
	 * should be called for every clock instance or hwmod that is
	 * enabled, so the clkdm can be force woken up.
	 */
	if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps)
		return 0;

	spin_lock_irqsave(&clkdm->lock, flags);
	arch_clkdm->clkdm_clk_enable(clkdm);
	pwrdm_state_switch(clkdm->pwrdm.ptr);
	spin_unlock_irqrestore(&clkdm->lock, flags);

	pr_debug("clockdomain: %s: enabled\n", clkdm->name);

	return 0;
}

static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
{
	unsigned long flags;

	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
		return -EINVAL;

	if (atomic_read(&clkdm->usecount) == 0) {
		WARN_ON(1); /* underflow */
		return -ERANGE;
	}

	if (atomic_dec_return(&clkdm->usecount) > 0)
		return 0;

	spin_lock_irqsave(&clkdm->lock, flags);
	arch_clkdm->clkdm_clk_disable(clkdm);
	pwrdm_state_switch(clkdm->pwrdm.ptr);
	spin_unlock_irqrestore(&clkdm->lock, flags);

	pr_debug("clockdomain: %s: disabled\n", clkdm->name);

	return 0;
}

/**
 * clkdm_clk_enable - add an enabled downstream clock to this clkdm
 * @clkdm: struct clockdomain *
 * @clk: struct clk * of the enabled downstream clock
 *
 * Increment the usecount of the clockdomain @clkdm and ensure that it
 * is awake before @clk is enabled.  Intended to be called by
 * clk_enable() code.  If the clockdomain is in software-supervised
 * idle mode, force the clockdomain to wake.  If the clockdomain is in
 * hardware-supervised idle mode, add clkdm-pwrdm autodependencies, to
 * ensure that devices in the clockdomain can be read from/written to
 * by on-chip processors.  Returns -EINVAL if passed null pointers;
 * returns 0 upon success or if the clockdomain is in hwsup idle mode.
 */
int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
{
	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream clocks for debugging purposes?
	 */

	if (!clk)
		return -EINVAL;

	return _clkdm_clk_hwmod_enable(clkdm);
}

/**
 * clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 * @clkdm: struct clockdomain *
 * @clk: struct clk * of the disabled downstream clock
 *
 * Decrement the usecount of this clockdomain @clkdm when @clk is
 * disabled.  Intended to be called by clk_disable() code.  If the
 * clockdomain usecount goes to 0, put the clockdomain to sleep
 * (software-supervised mode) or remove the clkdm autodependencies
 * (hardware-supervised mode).  Returns -EINVAL if passed null
 * pointers; -ERANGE if the @clkdm usecount underflows; or returns 0
 * upon success or if the clockdomain is in hwsup idle mode.
 */
int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
{
	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream clocks for debugging purposes?
	 */

	if (!clk)
		return -EINVAL;

	return _clkdm_clk_hwmod_disable(clkdm);
}

/**
 * clkdm_hwmod_enable - add an enabled downstream hwmod to this clkdm
 * @clkdm: struct clockdomain *
 * @oh: struct omap_hwmod * of the enabled downstream hwmod
 *
 * Increment the usecount of the clockdomain @clkdm and ensure that it
 * is awake before @oh is enabled. Intended to be called by
 * module_enable() code.
 * If the clockdomain is in software-supervised idle mode, force the
 * clockdomain to wake.  If the clockdomain is in hardware-supervised idle
 * mode, add clkdm-pwrdm autodependencies, to ensure that devices in the
 * clockdomain can be read from/written to by on-chip processors.
 * Returns -EINVAL if passed null pointers;
 * returns 0 upon success or if the clockdomain is in hwsup idle mode.
 */
int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh)
{
	/* The clkdm attribute does not exist yet prior OMAP4 */
	if (cpu_is_omap24xx() || cpu_is_omap34xx())
		return 0;

	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream hwmods for debugging purposes?
	 */

	if (!oh)
		return -EINVAL;

	return _clkdm_clk_hwmod_enable(clkdm);
}

/**
 * clkdm_hwmod_disable - remove an enabled downstream hwmod from this clkdm
 * @clkdm: struct clockdomain *
 * @oh: struct omap_hwmod * of the disabled downstream hwmod
 *
 * Decrement the usecount of this clockdomain @clkdm when @oh is
 * disabled. Intended to be called by module_disable() code.
 * If the clockdomain usecount goes to 0, put the clockdomain to sleep
 * (software-supervised mode) or remove the clkdm autodependencies
 * (hardware-supervised mode).
 * Returns -EINVAL if passed null pointers; -ERANGE if the @clkdm usecount
 * underflows; or returns 0 upon success or if the clockdomain is in hwsup
 * idle mode.
 */
int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
{
	/* The clkdm attribute does not exist yet prior OMAP4 */
	if (cpu_is_omap24xx() || cpu_is_omap34xx())
		return 0;

	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream hwmods for debugging purposes?
	 */

	if (!oh)
		return -EINVAL;

	return _clkdm_clk_hwmod_disable(clkdm);
}