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1/*
2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Standard functionality for the common clock API. See Documentation/clk.txt
10 */
11
12#include <linux/clk-private.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/spinlock.h>
16#include <linux/err.h>
17#include <linux/list.h>
18#include <linux/slab.h>
19
20static DEFINE_SPINLOCK(enable_lock);
21static DEFINE_MUTEX(prepare_lock);
22
23static HLIST_HEAD(clk_root_list);
24static HLIST_HEAD(clk_orphan_list);
25static LIST_HEAD(clk_notifier_list);
26
27/*** debugfs support ***/
28
29#ifdef CONFIG_COMMON_CLK_DEBUG
30#include <linux/debugfs.h>
31
32static struct dentry *rootdir;
33static struct dentry *orphandir;
34static int inited = 0;
35
36/* caller must hold prepare_lock */
37static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
38{
39 struct dentry *d;
40 int ret = -ENOMEM;
41
42 if (!clk || !pdentry) {
43 ret = -EINVAL;
44 goto out;
45 }
46
47 d = debugfs_create_dir(clk->name, pdentry);
48 if (!d)
49 goto out;
50
51 clk->dentry = d;
52
53 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
54 (u32 *)&clk->rate);
55 if (!d)
56 goto err_out;
57
58 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
59 (u32 *)&clk->flags);
60 if (!d)
61 goto err_out;
62
63 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
64 (u32 *)&clk->prepare_count);
65 if (!d)
66 goto err_out;
67
68 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
69 (u32 *)&clk->enable_count);
70 if (!d)
71 goto err_out;
72
73 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
74 (u32 *)&clk->notifier_count);
75 if (!d)
76 goto err_out;
77
78 ret = 0;
79 goto out;
80
81err_out:
82 debugfs_remove(clk->dentry);
83out:
84 return ret;
85}
86
87/* caller must hold prepare_lock */
88static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
89{
90 struct clk *child;
91 struct hlist_node *tmp;
92 int ret = -EINVAL;;
93
94 if (!clk || !pdentry)
95 goto out;
96
97 ret = clk_debug_create_one(clk, pdentry);
98
99 if (ret)
100 goto out;
101
102 hlist_for_each_entry(child, tmp, &clk->children, child_node)
103 clk_debug_create_subtree(child, clk->dentry);
104
105 ret = 0;
106out:
107 return ret;
108}
109
110/**
111 * clk_debug_register - add a clk node to the debugfs clk tree
112 * @clk: the clk being added to the debugfs clk tree
113 *
114 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
115 * initialized. Otherwise it bails out early since the debugfs clk tree
116 * will be created lazily by clk_debug_init as part of a late_initcall.
117 *
118 * Caller must hold prepare_lock. Only clk_init calls this function (so
119 * far) so this is taken care.
120 */
121static int clk_debug_register(struct clk *clk)
122{
123 struct clk *parent;
124 struct dentry *pdentry;
125 int ret = 0;
126
127 if (!inited)
128 goto out;
129
130 parent = clk->parent;
131
132 /*
133 * Check to see if a clk is a root clk. Also check that it is
134 * safe to add this clk to debugfs
135 */
136 if (!parent)
137 if (clk->flags & CLK_IS_ROOT)
138 pdentry = rootdir;
139 else
140 pdentry = orphandir;
141 else
142 if (parent->dentry)
143 pdentry = parent->dentry;
144 else
145 goto out;
146
147 ret = clk_debug_create_subtree(clk, pdentry);
148
149out:
150 return ret;
151}
152
153/**
154 * clk_debug_init - lazily create the debugfs clk tree visualization
155 *
156 * clks are often initialized very early during boot before memory can
157 * be dynamically allocated and well before debugfs is setup.
158 * clk_debug_init walks the clk tree hierarchy while holding
159 * prepare_lock and creates the topology as part of a late_initcall,
160 * thus insuring that clks initialized very early will still be
161 * represented in the debugfs clk tree. This function should only be
162 * called once at boot-time, and all other clks added dynamically will
163 * be done so with clk_debug_register.
164 */
165static int __init clk_debug_init(void)
166{
167 struct clk *clk;
168 struct hlist_node *tmp;
169
170 rootdir = debugfs_create_dir("clk", NULL);
171
172 if (!rootdir)
173 return -ENOMEM;
174
175 orphandir = debugfs_create_dir("orphans", rootdir);
176
177 if (!orphandir)
178 return -ENOMEM;
179
180 mutex_lock(&prepare_lock);
181
182 hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
183 clk_debug_create_subtree(clk, rootdir);
184
185 hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
186 clk_debug_create_subtree(clk, orphandir);
187
188 inited = 1;
189
190 mutex_unlock(&prepare_lock);
191
192 return 0;
193}
194late_initcall(clk_debug_init);
195#else
196static inline int clk_debug_register(struct clk *clk) { return 0; }
197#endif
198
199/* caller must hold prepare_lock */
200static void clk_disable_unused_subtree(struct clk *clk)
201{
202 struct clk *child;
203 struct hlist_node *tmp;
204 unsigned long flags;
205
206 if (!clk)
207 goto out;
208
209 hlist_for_each_entry(child, tmp, &clk->children, child_node)
210 clk_disable_unused_subtree(child);
211
212 spin_lock_irqsave(&enable_lock, flags);
213
214 if (clk->enable_count)
215 goto unlock_out;
216
217 if (clk->flags & CLK_IGNORE_UNUSED)
218 goto unlock_out;
219
220 if (__clk_is_enabled(clk) && clk->ops->disable)
221 clk->ops->disable(clk->hw);
222
223unlock_out:
224 spin_unlock_irqrestore(&enable_lock, flags);
225
226out:
227 return;
228}
229
230static int clk_disable_unused(void)
231{
232 struct clk *clk;
233 struct hlist_node *tmp;
234
235 mutex_lock(&prepare_lock);
236
237 hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
238 clk_disable_unused_subtree(clk);
239
240 hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
241 clk_disable_unused_subtree(clk);
242
243 mutex_unlock(&prepare_lock);
244
245 return 0;
246}
247late_initcall(clk_disable_unused);
248
249/*** helper functions ***/
250
251inline const char *__clk_get_name(struct clk *clk)
252{
253 return !clk ? NULL : clk->name;
254}
255
256inline struct clk_hw *__clk_get_hw(struct clk *clk)
257{
258 return !clk ? NULL : clk->hw;
259}
260
261inline u8 __clk_get_num_parents(struct clk *clk)
262{
263 return !clk ? -EINVAL : clk->num_parents;
264}
265
266inline struct clk *__clk_get_parent(struct clk *clk)
267{
268 return !clk ? NULL : clk->parent;
269}
270
271inline int __clk_get_enable_count(struct clk *clk)
272{
273 return !clk ? -EINVAL : clk->enable_count;
274}
275
276inline int __clk_get_prepare_count(struct clk *clk)
277{
278 return !clk ? -EINVAL : clk->prepare_count;
279}
280
281unsigned long __clk_get_rate(struct clk *clk)
282{
283 unsigned long ret;
284
285 if (!clk) {
286 ret = 0;
287 goto out;
288 }
289
290 ret = clk->rate;
291
292 if (clk->flags & CLK_IS_ROOT)
293 goto out;
294
295 if (!clk->parent)
296 ret = 0;
297
298out:
299 return ret;
300}
301
302inline unsigned long __clk_get_flags(struct clk *clk)
303{
304 return !clk ? -EINVAL : clk->flags;
305}
306
307int __clk_is_enabled(struct clk *clk)
308{
309 int ret;
310
311 if (!clk)
312 return -EINVAL;
313
314 /*
315 * .is_enabled is only mandatory for clocks that gate
316 * fall back to software usage counter if .is_enabled is missing
317 */
318 if (!clk->ops->is_enabled) {
319 ret = clk->enable_count ? 1 : 0;
320 goto out;
321 }
322
323 ret = clk->ops->is_enabled(clk->hw);
324out:
325 return ret;
326}
327
328static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
329{
330 struct clk *child;
331 struct clk *ret;
332 struct hlist_node *tmp;
333
334 if (!strcmp(clk->name, name))
335 return clk;
336
337 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
338 ret = __clk_lookup_subtree(name, child);
339 if (ret)
340 return ret;
341 }
342
343 return NULL;
344}
345
346struct clk *__clk_lookup(const char *name)
347{
348 struct clk *root_clk;
349 struct clk *ret;
350 struct hlist_node *tmp;
351
352 if (!name)
353 return NULL;
354
355 /* search the 'proper' clk tree first */
356 hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) {
357 ret = __clk_lookup_subtree(name, root_clk);
358 if (ret)
359 return ret;
360 }
361
362 /* if not found, then search the orphan tree */
363 hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) {
364 ret = __clk_lookup_subtree(name, root_clk);
365 if (ret)
366 return ret;
367 }
368
369 return NULL;
370}
371
372/*** clk api ***/
373
374void __clk_unprepare(struct clk *clk)
375{
376 if (!clk)
377 return;
378
379 if (WARN_ON(clk->prepare_count == 0))
380 return;
381
382 if (--clk->prepare_count > 0)
383 return;
384
385 WARN_ON(clk->enable_count > 0);
386
387 if (clk->ops->unprepare)
388 clk->ops->unprepare(clk->hw);
389
390 __clk_unprepare(clk->parent);
391}
392
393/**
394 * clk_unprepare - undo preparation of a clock source
395 * @clk: the clk being unprepare
396 *
397 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
398 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
399 * if the operation may sleep. One example is a clk which is accessed over
400 * I2c. In the complex case a clk gate operation may require a fast and a slow
401 * part. It is this reason that clk_unprepare and clk_disable are not mutually
402 * exclusive. In fact clk_disable must be called before clk_unprepare.
403 */
404void clk_unprepare(struct clk *clk)
405{
406 mutex_lock(&prepare_lock);
407 __clk_unprepare(clk);
408 mutex_unlock(&prepare_lock);
409}
410EXPORT_SYMBOL_GPL(clk_unprepare);
411
412int __clk_prepare(struct clk *clk)
413{
414 int ret = 0;
415
416 if (!clk)
417 return 0;
418
419 if (clk->prepare_count == 0) {
420 ret = __clk_prepare(clk->parent);
421 if (ret)
422 return ret;
423
424 if (clk->ops->prepare) {
425 ret = clk->ops->prepare(clk->hw);
426 if (ret) {
427 __clk_unprepare(clk->parent);
428 return ret;
429 }
430 }
431 }
432
433 clk->prepare_count++;
434
435 return 0;
436}
437
438/**
439 * clk_prepare - prepare a clock source
440 * @clk: the clk being prepared
441 *
442 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
443 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
444 * operation may sleep. One example is a clk which is accessed over I2c. In
445 * the complex case a clk ungate operation may require a fast and a slow part.
446 * It is this reason that clk_prepare and clk_enable are not mutually
447 * exclusive. In fact clk_prepare must be called before clk_enable.
448 * Returns 0 on success, -EERROR otherwise.
449 */
450int clk_prepare(struct clk *clk)
451{
452 int ret;
453
454 mutex_lock(&prepare_lock);
455 ret = __clk_prepare(clk);
456 mutex_unlock(&prepare_lock);
457
458 return ret;
459}
460EXPORT_SYMBOL_GPL(clk_prepare);
461
462static void __clk_disable(struct clk *clk)
463{
464 if (!clk)
465 return;
466
467 if (WARN_ON(clk->enable_count == 0))
468 return;
469
470 if (--clk->enable_count > 0)
471 return;
472
473 if (clk->ops->disable)
474 clk->ops->disable(clk->hw);
475
476 __clk_disable(clk->parent);
477}
478
479/**
480 * clk_disable - gate a clock
481 * @clk: the clk being gated
482 *
483 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
484 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
485 * clk if the operation is fast and will never sleep. One example is a
486 * SoC-internal clk which is controlled via simple register writes. In the
487 * complex case a clk gate operation may require a fast and a slow part. It is
488 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
489 * In fact clk_disable must be called before clk_unprepare.
490 */
491void clk_disable(struct clk *clk)
492{
493 unsigned long flags;
494
495 spin_lock_irqsave(&enable_lock, flags);
496 __clk_disable(clk);
497 spin_unlock_irqrestore(&enable_lock, flags);
498}
499EXPORT_SYMBOL_GPL(clk_disable);
500
501static int __clk_enable(struct clk *clk)
502{
503 int ret = 0;
504
505 if (!clk)
506 return 0;
507
508 if (WARN_ON(clk->prepare_count == 0))
509 return -ESHUTDOWN;
510
511 if (clk->enable_count == 0) {
512 ret = __clk_enable(clk->parent);
513
514 if (ret)
515 return ret;
516
517 if (clk->ops->enable) {
518 ret = clk->ops->enable(clk->hw);
519 if (ret) {
520 __clk_disable(clk->parent);
521 return ret;
522 }
523 }
524 }
525
526 clk->enable_count++;
527 return 0;
528}
529
530/**
531 * clk_enable - ungate a clock
532 * @clk: the clk being ungated
533 *
534 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
535 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
536 * if the operation will never sleep. One example is a SoC-internal clk which
537 * is controlled via simple register writes. In the complex case a clk ungate
538 * operation may require a fast and a slow part. It is this reason that
539 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
540 * must be called before clk_enable. Returns 0 on success, -EERROR
541 * otherwise.
542 */
543int clk_enable(struct clk *clk)
544{
545 unsigned long flags;
546 int ret;
547
548 spin_lock_irqsave(&enable_lock, flags);
549 ret = __clk_enable(clk);
550 spin_unlock_irqrestore(&enable_lock, flags);
551
552 return ret;
553}
554EXPORT_SYMBOL_GPL(clk_enable);
555
556/**
557 * clk_get_rate - return the rate of clk
558 * @clk: the clk whose rate is being returned
559 *
560 * Simply returns the cached rate of the clk. Does not query the hardware. If
561 * clk is NULL then returns 0.
562 */
563unsigned long clk_get_rate(struct clk *clk)
564{
565 unsigned long rate;
566
567 mutex_lock(&prepare_lock);
568 rate = __clk_get_rate(clk);
569 mutex_unlock(&prepare_lock);
570
571 return rate;
572}
573EXPORT_SYMBOL_GPL(clk_get_rate);
574
575/**
576 * __clk_round_rate - round the given rate for a clk
577 * @clk: round the rate of this clock
578 *
579 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
580 */
581unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
582{
583 unsigned long parent_rate = 0;
584
585 if (!clk)
586 return -EINVAL;
587
588 if (!clk->ops->round_rate) {
589 if (clk->flags & CLK_SET_RATE_PARENT)
590 return __clk_round_rate(clk->parent, rate);
591 else
592 return clk->rate;
593 }
594
595 if (clk->parent)
596 parent_rate = clk->parent->rate;
597
598 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
599}
600
601/**
602 * clk_round_rate - round the given rate for a clk
603 * @clk: the clk for which we are rounding a rate
604 * @rate: the rate which is to be rounded
605 *
606 * Takes in a rate as input and rounds it to a rate that the clk can actually
607 * use which is then returned. If clk doesn't support round_rate operation
608 * then the parent rate is returned.
609 */
610long clk_round_rate(struct clk *clk, unsigned long rate)
611{
612 unsigned long ret;
613
614 mutex_lock(&prepare_lock);
615 ret = __clk_round_rate(clk, rate);
616 mutex_unlock(&prepare_lock);
617
618 return ret;
619}
620EXPORT_SYMBOL_GPL(clk_round_rate);
621
622/**
623 * __clk_notify - call clk notifier chain
624 * @clk: struct clk * that is changing rate
625 * @msg: clk notifier type (see include/linux/clk.h)
626 * @old_rate: old clk rate
627 * @new_rate: new clk rate
628 *
629 * Triggers a notifier call chain on the clk rate-change notification
630 * for 'clk'. Passes a pointer to the struct clk and the previous
631 * and current rates to the notifier callback. Intended to be called by
632 * internal clock code only. Returns NOTIFY_DONE from the last driver
633 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
634 * a driver returns that.
635 */
636static int __clk_notify(struct clk *clk, unsigned long msg,
637 unsigned long old_rate, unsigned long new_rate)
638{
639 struct clk_notifier *cn;
640 struct clk_notifier_data cnd;
641 int ret = NOTIFY_DONE;
642
643 cnd.clk = clk;
644 cnd.old_rate = old_rate;
645 cnd.new_rate = new_rate;
646
647 list_for_each_entry(cn, &clk_notifier_list, node) {
648 if (cn->clk == clk) {
649 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
650 &cnd);
651 break;
652 }
653 }
654
655 return ret;
656}
657
658/**
659 * __clk_recalc_rates
660 * @clk: first clk in the subtree
661 * @msg: notification type (see include/linux/clk.h)
662 *
663 * Walks the subtree of clks starting with clk and recalculates rates as it
664 * goes. Note that if a clk does not implement the .recalc_rate callback then
665 * it is assumed that the clock will take on the rate of it's parent.
666 *
667 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
668 * if necessary.
669 *
670 * Caller must hold prepare_lock.
671 */
672static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
673{
674 unsigned long old_rate;
675 unsigned long parent_rate = 0;
676 struct hlist_node *tmp;
677 struct clk *child;
678
679 old_rate = clk->rate;
680
681 if (clk->parent)
682 parent_rate = clk->parent->rate;
683
684 if (clk->ops->recalc_rate)
685 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
686 else
687 clk->rate = parent_rate;
688
689 /*
690 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
691 * & ABORT_RATE_CHANGE notifiers
692 */
693 if (clk->notifier_count && msg)
694 __clk_notify(clk, msg, old_rate, clk->rate);
695
696 hlist_for_each_entry(child, tmp, &clk->children, child_node)
697 __clk_recalc_rates(child, msg);
698}
699
700/**
701 * __clk_speculate_rates
702 * @clk: first clk in the subtree
703 * @parent_rate: the "future" rate of clk's parent
704 *
705 * Walks the subtree of clks starting with clk, speculating rates as it
706 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
707 *
708 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
709 * pre-rate change notifications and returns early if no clks in the
710 * subtree have subscribed to the notifications. Note that if a clk does not
711 * implement the .recalc_rate callback then it is assumed that the clock will
712 * take on the rate of it's parent.
713 *
714 * Caller must hold prepare_lock.
715 */
716static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
717{
718 struct hlist_node *tmp;
719 struct clk *child;
720 unsigned long new_rate;
721 int ret = NOTIFY_DONE;
722
723 if (clk->ops->recalc_rate)
724 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
725 else
726 new_rate = parent_rate;
727
728 /* abort the rate change if a driver returns NOTIFY_BAD */
729 if (clk->notifier_count)
730 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
731
732 if (ret == NOTIFY_BAD)
733 goto out;
734
735 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
736 ret = __clk_speculate_rates(child, new_rate);
737 if (ret == NOTIFY_BAD)
738 break;
739 }
740
741out:
742 return ret;
743}
744
745static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
746{
747 struct clk *child;
748 struct hlist_node *tmp;
749
750 clk->new_rate = new_rate;
751
752 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
753 if (child->ops->recalc_rate)
754 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
755 else
756 child->new_rate = new_rate;
757 clk_calc_subtree(child, child->new_rate);
758 }
759}
760
761/*
762 * calculate the new rates returning the topmost clock that has to be
763 * changed.
764 */
765static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
766{
767 struct clk *top = clk;
768 unsigned long best_parent_rate = 0;
769 unsigned long new_rate;
770
771 /* sanity */
772 if (IS_ERR_OR_NULL(clk))
773 return NULL;
774
775 /* save parent rate, if it exists */
776 if (clk->parent)
777 best_parent_rate = clk->parent->rate;
778
779 /* never propagate up to the parent */
780 if (!(clk->flags & CLK_SET_RATE_PARENT)) {
781 if (!clk->ops->round_rate) {
782 clk->new_rate = clk->rate;
783 return NULL;
784 }
785 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
786 goto out;
787 }
788
789 /* need clk->parent from here on out */
790 if (!clk->parent) {
791 pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
792 return NULL;
793 }
794
795 if (!clk->ops->round_rate) {
796 top = clk_calc_new_rates(clk->parent, rate);
797 new_rate = clk->parent->new_rate;
798
799 goto out;
800 }
801
802 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
803
804 if (best_parent_rate != clk->parent->rate) {
805 top = clk_calc_new_rates(clk->parent, best_parent_rate);
806
807 goto out;
808 }
809
810out:
811 clk_calc_subtree(clk, new_rate);
812
813 return top;
814}
815
816/*
817 * Notify about rate changes in a subtree. Always walk down the whole tree
818 * so that in case of an error we can walk down the whole tree again and
819 * abort the change.
820 */
821static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
822{
823 struct hlist_node *tmp;
824 struct clk *child, *fail_clk = NULL;
825 int ret = NOTIFY_DONE;
826
827 if (clk->rate == clk->new_rate)
828 return 0;
829
830 if (clk->notifier_count) {
831 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
832 if (ret == NOTIFY_BAD)
833 fail_clk = clk;
834 }
835
836 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
837 clk = clk_propagate_rate_change(child, event);
838 if (clk)
839 fail_clk = clk;
840 }
841
842 return fail_clk;
843}
844
845/*
846 * walk down a subtree and set the new rates notifying the rate
847 * change on the way
848 */
849static void clk_change_rate(struct clk *clk)
850{
851 struct clk *child;
852 unsigned long old_rate;
853 unsigned long best_parent_rate = 0;
854 struct hlist_node *tmp;
855
856 old_rate = clk->rate;
857
858 if (clk->parent)
859 best_parent_rate = clk->parent->rate;
860
861 if (clk->ops->set_rate)
862 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
863
864 if (clk->ops->recalc_rate)
865 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
866 else
867 clk->rate = best_parent_rate;
868
869 if (clk->notifier_count && old_rate != clk->rate)
870 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
871
872 hlist_for_each_entry(child, tmp, &clk->children, child_node)
873 clk_change_rate(child);
874}
875
876/**
877 * clk_set_rate - specify a new rate for clk
878 * @clk: the clk whose rate is being changed
879 * @rate: the new rate for clk
880 *
881 * In the simplest case clk_set_rate will only adjust the rate of clk.
882 *
883 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
884 * propagate up to clk's parent; whether or not this happens depends on the
885 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
886 * after calling .round_rate then upstream parent propagation is ignored. If
887 * *parent_rate comes back with a new rate for clk's parent then we propagate
888 * up to clk's parent and set it's rate. Upward propagation will continue
889 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
890 * .round_rate stops requesting changes to clk's parent_rate.
891 *
892 * Rate changes are accomplished via tree traversal that also recalculates the
893 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
894 *
895 * Returns 0 on success, -EERROR otherwise.
896 */
897int clk_set_rate(struct clk *clk, unsigned long rate)
898{
899 struct clk *top, *fail_clk;
900 int ret = 0;
901
902 /* prevent racing with updates to the clock topology */
903 mutex_lock(&prepare_lock);
904
905 /* bail early if nothing to do */
906 if (rate == clk->rate)
907 goto out;
908
909 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
910 ret = -EBUSY;
911 goto out;
912 }
913
914 /* calculate new rates and get the topmost changed clock */
915 top = clk_calc_new_rates(clk, rate);
916 if (!top) {
917 ret = -EINVAL;
918 goto out;
919 }
920
921 /* notify that we are about to change rates */
922 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
923 if (fail_clk) {
924 pr_warn("%s: failed to set %s rate\n", __func__,
925 fail_clk->name);
926 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
927 ret = -EBUSY;
928 goto out;
929 }
930
931 /* change the rates */
932 clk_change_rate(top);
933
934 mutex_unlock(&prepare_lock);
935
936 return 0;
937out:
938 mutex_unlock(&prepare_lock);
939
940 return ret;
941}
942EXPORT_SYMBOL_GPL(clk_set_rate);
943
944/**
945 * clk_get_parent - return the parent of a clk
946 * @clk: the clk whose parent gets returned
947 *
948 * Simply returns clk->parent. Returns NULL if clk is NULL.
949 */
950struct clk *clk_get_parent(struct clk *clk)
951{
952 struct clk *parent;
953
954 mutex_lock(&prepare_lock);
955 parent = __clk_get_parent(clk);
956 mutex_unlock(&prepare_lock);
957
958 return parent;
959}
960EXPORT_SYMBOL_GPL(clk_get_parent);
961
962/*
963 * .get_parent is mandatory for clocks with multiple possible parents. It is
964 * optional for single-parent clocks. Always call .get_parent if it is
965 * available and WARN if it is missing for multi-parent clocks.
966 *
967 * For single-parent clocks without .get_parent, first check to see if the
968 * .parents array exists, and if so use it to avoid an expensive tree
969 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
970 */
971static struct clk *__clk_init_parent(struct clk *clk)
972{
973 struct clk *ret = NULL;
974 u8 index;
975
976 /* handle the trivial cases */
977
978 if (!clk->num_parents)
979 goto out;
980
981 if (clk->num_parents == 1) {
982 if (IS_ERR_OR_NULL(clk->parent))
983 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
984 ret = clk->parent;
985 goto out;
986 }
987
988 if (!clk->ops->get_parent) {
989 WARN(!clk->ops->get_parent,
990 "%s: multi-parent clocks must implement .get_parent\n",
991 __func__);
992 goto out;
993 };
994
995 /*
996 * Do our best to cache parent clocks in clk->parents. This prevents
997 * unnecessary and expensive calls to __clk_lookup. We don't set
998 * clk->parent here; that is done by the calling function
999 */
1000
1001 index = clk->ops->get_parent(clk->hw);
1002
1003 if (!clk->parents)
1004 clk->parents =
1005 kzalloc((sizeof(struct clk*) * clk->num_parents),
1006 GFP_KERNEL);
1007
1008 if (!clk->parents)
1009 ret = __clk_lookup(clk->parent_names[index]);
1010 else if (!clk->parents[index])
1011 ret = clk->parents[index] =
1012 __clk_lookup(clk->parent_names[index]);
1013 else
1014 ret = clk->parents[index];
1015
1016out:
1017 return ret;
1018}
1019
1020void __clk_reparent(struct clk *clk, struct clk *new_parent)
1021{
1022#ifdef CONFIG_COMMON_CLK_DEBUG
1023 struct dentry *d;
1024 struct dentry *new_parent_d;
1025#endif
1026
1027 if (!clk || !new_parent)
1028 return;
1029
1030 hlist_del(&clk->child_node);
1031
1032 if (new_parent)
1033 hlist_add_head(&clk->child_node, &new_parent->children);
1034 else
1035 hlist_add_head(&clk->child_node, &clk_orphan_list);
1036
1037#ifdef CONFIG_COMMON_CLK_DEBUG
1038 if (!inited)
1039 goto out;
1040
1041 if (new_parent)
1042 new_parent_d = new_parent->dentry;
1043 else
1044 new_parent_d = orphandir;
1045
1046 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
1047 new_parent_d, clk->name);
1048 if (d)
1049 clk->dentry = d;
1050 else
1051 pr_debug("%s: failed to rename debugfs entry for %s\n",
1052 __func__, clk->name);
1053out:
1054#endif
1055
1056 clk->parent = new_parent;
1057
1058 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1059}
1060
1061static int __clk_set_parent(struct clk *clk, struct clk *parent)
1062{
1063 struct clk *old_parent;
1064 unsigned long flags;
1065 int ret = -EINVAL;
1066 u8 i;
1067
1068 old_parent = clk->parent;
1069
1070 if (!clk->parents)
1071 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1072 GFP_KERNEL);
1073
1074 /*
1075 * find index of new parent clock using cached parent ptrs,
1076 * or if not yet cached, use string name comparison and cache
1077 * them now to avoid future calls to __clk_lookup.
1078 */
1079 for (i = 0; i < clk->num_parents; i++) {
1080 if (clk->parents && clk->parents[i] == parent)
1081 break;
1082 else if (!strcmp(clk->parent_names[i], parent->name)) {
1083 if (clk->parents)
1084 clk->parents[i] = __clk_lookup(parent->name);
1085 break;
1086 }
1087 }
1088
1089 if (i == clk->num_parents) {
1090 pr_debug("%s: clock %s is not a possible parent of clock %s\n",
1091 __func__, parent->name, clk->name);
1092 goto out;
1093 }
1094
1095 /* migrate prepare and enable */
1096 if (clk->prepare_count)
1097 __clk_prepare(parent);
1098
1099 /* FIXME replace with clk_is_enabled(clk) someday */
1100 spin_lock_irqsave(&enable_lock, flags);
1101 if (clk->enable_count)
1102 __clk_enable(parent);
1103 spin_unlock_irqrestore(&enable_lock, flags);
1104
1105 /* change clock input source */
1106 ret = clk->ops->set_parent(clk->hw, i);
1107
1108 /* clean up old prepare and enable */
1109 spin_lock_irqsave(&enable_lock, flags);
1110 if (clk->enable_count)
1111 __clk_disable(old_parent);
1112 spin_unlock_irqrestore(&enable_lock, flags);
1113
1114 if (clk->prepare_count)
1115 __clk_unprepare(old_parent);
1116
1117out:
1118 return ret;
1119}
1120
1121/**
1122 * clk_set_parent - switch the parent of a mux clk
1123 * @clk: the mux clk whose input we are switching
1124 * @parent: the new input to clk
1125 *
1126 * Re-parent clk to use parent as it's new input source. If clk has the
1127 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1128 * operation to succeed. After successfully changing clk's parent
1129 * clk_set_parent will update the clk topology, sysfs topology and
1130 * propagate rate recalculation via __clk_recalc_rates. Returns 0 on
1131 * success, -EERROR otherwise.
1132 */
1133int clk_set_parent(struct clk *clk, struct clk *parent)
1134{
1135 int ret = 0;
1136
1137 if (!clk || !clk->ops)
1138 return -EINVAL;
1139
1140 if (!clk->ops->set_parent)
1141 return -ENOSYS;
1142
1143 /* prevent racing with updates to the clock topology */
1144 mutex_lock(&prepare_lock);
1145
1146 if (clk->parent == parent)
1147 goto out;
1148
1149 /* propagate PRE_RATE_CHANGE notifications */
1150 if (clk->notifier_count)
1151 ret = __clk_speculate_rates(clk, parent->rate);
1152
1153 /* abort if a driver objects */
1154 if (ret == NOTIFY_STOP)
1155 goto out;
1156
1157 /* only re-parent if the clock is not in use */
1158 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
1159 ret = -EBUSY;
1160 else
1161 ret = __clk_set_parent(clk, parent);
1162
1163 /* propagate ABORT_RATE_CHANGE if .set_parent failed */
1164 if (ret) {
1165 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1166 goto out;
1167 }
1168
1169 /* propagate rate recalculation downstream */
1170 __clk_reparent(clk, parent);
1171
1172out:
1173 mutex_unlock(&prepare_lock);
1174
1175 return ret;
1176}
1177EXPORT_SYMBOL_GPL(clk_set_parent);
1178
1179/**
1180 * __clk_init - initialize the data structures in a struct clk
1181 * @dev: device initializing this clk, placeholder for now
1182 * @clk: clk being initialized
1183 *
1184 * Initializes the lists in struct clk, queries the hardware for the
1185 * parent and rate and sets them both.
1186 */
1187int __clk_init(struct device *dev, struct clk *clk)
1188{
1189 int i, ret = 0;
1190 struct clk *orphan;
1191 struct hlist_node *tmp, *tmp2;
1192
1193 if (!clk)
1194 return -EINVAL;
1195
1196 mutex_lock(&prepare_lock);
1197
1198 /* check to see if a clock with this name is already registered */
1199 if (__clk_lookup(clk->name)) {
1200 pr_debug("%s: clk %s already initialized\n",
1201 __func__, clk->name);
1202 ret = -EEXIST;
1203 goto out;
1204 }
1205
1206 /* check that clk_ops are sane. See Documentation/clk.txt */
1207 if (clk->ops->set_rate &&
1208 !(clk->ops->round_rate && clk->ops->recalc_rate)) {
1209 pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1210 __func__, clk->name);
1211 ret = -EINVAL;
1212 goto out;
1213 }
1214
1215 if (clk->ops->set_parent && !clk->ops->get_parent) {
1216 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1217 __func__, clk->name);
1218 ret = -EINVAL;
1219 goto out;
1220 }
1221
1222 /* throw a WARN if any entries in parent_names are NULL */
1223 for (i = 0; i < clk->num_parents; i++)
1224 WARN(!clk->parent_names[i],
1225 "%s: invalid NULL in %s's .parent_names\n",
1226 __func__, clk->name);
1227
1228 /*
1229 * Allocate an array of struct clk *'s to avoid unnecessary string
1230 * look-ups of clk's possible parents. This can fail for clocks passed
1231 * in to clk_init during early boot; thus any access to clk->parents[]
1232 * must always check for a NULL pointer and try to populate it if
1233 * necessary.
1234 *
1235 * If clk->parents is not NULL we skip this entire block. This allows
1236 * for clock drivers to statically initialize clk->parents.
1237 */
1238 if (clk->num_parents && !clk->parents) {
1239 clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents),
1240 GFP_KERNEL);
1241 /*
1242 * __clk_lookup returns NULL for parents that have not been
1243 * clk_init'd; thus any access to clk->parents[] must check
1244 * for a NULL pointer. We can always perform lazy lookups for
1245 * missing parents later on.
1246 */
1247 if (clk->parents)
1248 for (i = 0; i < clk->num_parents; i++)
1249 clk->parents[i] =
1250 __clk_lookup(clk->parent_names[i]);
1251 }
1252
1253 clk->parent = __clk_init_parent(clk);
1254
1255 /*
1256 * Populate clk->parent if parent has already been __clk_init'd. If
1257 * parent has not yet been __clk_init'd then place clk in the orphan
1258 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1259 * clk list.
1260 *
1261 * Every time a new clk is clk_init'd then we walk the list of orphan
1262 * clocks and re-parent any that are children of the clock currently
1263 * being clk_init'd.
1264 */
1265 if (clk->parent)
1266 hlist_add_head(&clk->child_node,
1267 &clk->parent->children);
1268 else if (clk->flags & CLK_IS_ROOT)
1269 hlist_add_head(&clk->child_node, &clk_root_list);
1270 else
1271 hlist_add_head(&clk->child_node, &clk_orphan_list);
1272
1273 /*
1274 * Set clk's rate. The preferred method is to use .recalc_rate. For
1275 * simple clocks and lazy developers the default fallback is to use the
1276 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1277 * then rate is set to zero.
1278 */
1279 if (clk->ops->recalc_rate)
1280 clk->rate = clk->ops->recalc_rate(clk->hw,
1281 __clk_get_rate(clk->parent));
1282 else if (clk->parent)
1283 clk->rate = clk->parent->rate;
1284 else
1285 clk->rate = 0;
1286
1287 /*
1288 * walk the list of orphan clocks and reparent any that are children of
1289 * this clock
1290 */
1291 hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node)
1292 for (i = 0; i < orphan->num_parents; i++)
1293 if (!strcmp(clk->name, orphan->parent_names[i])) {
1294 __clk_reparent(orphan, clk);
1295 break;
1296 }
1297
1298 /*
1299 * optional platform-specific magic
1300 *
1301 * The .init callback is not used by any of the basic clock types, but
1302 * exists for weird hardware that must perform initialization magic.
1303 * Please consider other ways of solving initialization problems before
1304 * using this callback, as it's use is discouraged.
1305 */
1306 if (clk->ops->init)
1307 clk->ops->init(clk->hw);
1308
1309 clk_debug_register(clk);
1310
1311out:
1312 mutex_unlock(&prepare_lock);
1313
1314 return ret;
1315}
1316
1317/**
1318 * __clk_register - register a clock and return a cookie.
1319 *
1320 * Same as clk_register, except that the .clk field inside hw shall point to a
1321 * preallocated (generally statically allocated) struct clk. None of the fields
1322 * of the struct clk need to be initialized.
1323 *
1324 * The data pointed to by .init and .clk field shall NOT be marked as init
1325 * data.
1326 *
1327 * __clk_register is only exposed via clk-private.h and is intended for use with
1328 * very large numbers of clocks that need to be statically initialized. It is
1329 * a layering violation to include clk-private.h from any code which implements
1330 * a clock's .ops; as such any statically initialized clock data MUST be in a
1331 * separate C file from the logic that implements it's operations. Returns 0
1332 * on success, otherwise an error code.
1333 */
1334struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1335{
1336 int ret;
1337 struct clk *clk;
1338
1339 clk = hw->clk;
1340 clk->name = hw->init->name;
1341 clk->ops = hw->init->ops;
1342 clk->hw = hw;
1343 clk->flags = hw->init->flags;
1344 clk->parent_names = hw->init->parent_names;
1345 clk->num_parents = hw->init->num_parents;
1346
1347 ret = __clk_init(dev, clk);
1348 if (ret)
1349 return ERR_PTR(ret);
1350
1351 return clk;
1352}
1353EXPORT_SYMBOL_GPL(__clk_register);
1354
1355/**
1356 * clk_register - allocate a new clock, register it and return an opaque cookie
1357 * @dev: device that is registering this clock
1358 * @hw: link to hardware-specific clock data
1359 *
1360 * clk_register is the primary interface for populating the clock tree with new
1361 * clock nodes. It returns a pointer to the newly allocated struct clk which
1362 * cannot be dereferenced by driver code but may be used in conjuction with the
1363 * rest of the clock API. In the event of an error clk_register will return an
1364 * error code; drivers must test for an error code after calling clk_register.
1365 */
1366struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1367{
1368 int i, ret;
1369 struct clk *clk;
1370
1371 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1372 if (!clk) {
1373 pr_err("%s: could not allocate clk\n", __func__);
1374 ret = -ENOMEM;
1375 goto fail_out;
1376 }
1377
1378 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1379 if (!clk->name) {
1380 pr_err("%s: could not allocate clk->name\n", __func__);
1381 ret = -ENOMEM;
1382 goto fail_name;
1383 }
1384 clk->ops = hw->init->ops;
1385 clk->hw = hw;
1386 clk->flags = hw->init->flags;
1387 clk->num_parents = hw->init->num_parents;
1388 hw->clk = clk;
1389
1390 /* allocate local copy in case parent_names is __initdata */
1391 clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
1392 GFP_KERNEL);
1393
1394 if (!clk->parent_names) {
1395 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1396 ret = -ENOMEM;
1397 goto fail_parent_names;
1398 }
1399
1400
1401 /* copy each string name in case parent_names is __initdata */
1402 for (i = 0; i < clk->num_parents; i++) {
1403 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1404 GFP_KERNEL);
1405 if (!clk->parent_names[i]) {
1406 pr_err("%s: could not copy parent_names\n", __func__);
1407 ret = -ENOMEM;
1408 goto fail_parent_names_copy;
1409 }
1410 }
1411
1412 ret = __clk_init(dev, clk);
1413 if (!ret)
1414 return clk;
1415
1416fail_parent_names_copy:
1417 while (--i >= 0)
1418 kfree(clk->parent_names[i]);
1419 kfree(clk->parent_names);
1420fail_parent_names:
1421 kfree(clk->name);
1422fail_name:
1423 kfree(clk);
1424fail_out:
1425 return ERR_PTR(ret);
1426}
1427EXPORT_SYMBOL_GPL(clk_register);
1428
1429/**
1430 * clk_unregister - unregister a currently registered clock
1431 * @clk: clock to unregister
1432 *
1433 * Currently unimplemented.
1434 */
1435void clk_unregister(struct clk *clk) {}
1436EXPORT_SYMBOL_GPL(clk_unregister);
1437
1438/*** clk rate change notifiers ***/
1439
1440/**
1441 * clk_notifier_register - add a clk rate change notifier
1442 * @clk: struct clk * to watch
1443 * @nb: struct notifier_block * with callback info
1444 *
1445 * Request notification when clk's rate changes. This uses an SRCU
1446 * notifier because we want it to block and notifier unregistrations are
1447 * uncommon. The callbacks associated with the notifier must not
1448 * re-enter into the clk framework by calling any top-level clk APIs;
1449 * this will cause a nested prepare_lock mutex.
1450 *
1451 * Pre-change notifier callbacks will be passed the current, pre-change
1452 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1453 * post-change rate of the clk is passed via struct
1454 * clk_notifier_data.new_rate.
1455 *
1456 * Post-change notifiers will pass the now-current, post-change rate of
1457 * the clk in both struct clk_notifier_data.old_rate and struct
1458 * clk_notifier_data.new_rate.
1459 *
1460 * Abort-change notifiers are effectively the opposite of pre-change
1461 * notifiers: the original pre-change clk rate is passed in via struct
1462 * clk_notifier_data.new_rate and the failed post-change rate is passed
1463 * in via struct clk_notifier_data.old_rate.
1464 *
1465 * clk_notifier_register() must be called from non-atomic context.
1466 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1467 * allocation failure; otherwise, passes along the return value of
1468 * srcu_notifier_chain_register().
1469 */
1470int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1471{
1472 struct clk_notifier *cn;
1473 int ret = -ENOMEM;
1474
1475 if (!clk || !nb)
1476 return -EINVAL;
1477
1478 mutex_lock(&prepare_lock);
1479
1480 /* search the list of notifiers for this clk */
1481 list_for_each_entry(cn, &clk_notifier_list, node)
1482 if (cn->clk == clk)
1483 break;
1484
1485 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1486 if (cn->clk != clk) {
1487 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1488 if (!cn)
1489 goto out;
1490
1491 cn->clk = clk;
1492 srcu_init_notifier_head(&cn->notifier_head);
1493
1494 list_add(&cn->node, &clk_notifier_list);
1495 }
1496
1497 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1498
1499 clk->notifier_count++;
1500
1501out:
1502 mutex_unlock(&prepare_lock);
1503
1504 return ret;
1505}
1506EXPORT_SYMBOL_GPL(clk_notifier_register);
1507
1508/**
1509 * clk_notifier_unregister - remove a clk rate change notifier
1510 * @clk: struct clk *
1511 * @nb: struct notifier_block * with callback info
1512 *
1513 * Request no further notification for changes to 'clk' and frees memory
1514 * allocated in clk_notifier_register.
1515 *
1516 * Returns -EINVAL if called with null arguments; otherwise, passes
1517 * along the return value of srcu_notifier_chain_unregister().
1518 */
1519int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1520{
1521 struct clk_notifier *cn = NULL;
1522 int ret = -EINVAL;
1523
1524 if (!clk || !nb)
1525 return -EINVAL;
1526
1527 mutex_lock(&prepare_lock);
1528
1529 list_for_each_entry(cn, &clk_notifier_list, node)
1530 if (cn->clk == clk)
1531 break;
1532
1533 if (cn->clk == clk) {
1534 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
1535
1536 clk->notifier_count--;
1537
1538 /* XXX the notifier code should handle this better */
1539 if (!cn->notifier_head.head) {
1540 srcu_cleanup_notifier_head(&cn->notifier_head);
1541 kfree(cn);
1542 }
1543
1544 } else {
1545 ret = -ENOENT;
1546 }
1547
1548 mutex_unlock(&prepare_lock);
1549
1550 return ret;
1551}
1552EXPORT_SYMBOL_GPL(clk_notifier_unregister);
1/*
2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Standard functionality for the common clock API. See Documentation/clk.txt
10 */
11
12#include <linux/clk.h>
13#include <linux/clk-provider.h>
14#include <linux/clk/clk-conf.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/spinlock.h>
18#include <linux/err.h>
19#include <linux/list.h>
20#include <linux/slab.h>
21#include <linux/of.h>
22#include <linux/device.h>
23#include <linux/init.h>
24#include <linux/sched.h>
25#include <linux/clkdev.h>
26
27#include "clk.h"
28
29static DEFINE_SPINLOCK(enable_lock);
30static DEFINE_MUTEX(prepare_lock);
31
32static struct task_struct *prepare_owner;
33static struct task_struct *enable_owner;
34
35static int prepare_refcnt;
36static int enable_refcnt;
37
38static HLIST_HEAD(clk_root_list);
39static HLIST_HEAD(clk_orphan_list);
40static LIST_HEAD(clk_notifier_list);
41
42/*** private data structures ***/
43
44struct clk_core {
45 const char *name;
46 const struct clk_ops *ops;
47 struct clk_hw *hw;
48 struct module *owner;
49 struct clk_core *parent;
50 const char **parent_names;
51 struct clk_core **parents;
52 u8 num_parents;
53 u8 new_parent_index;
54 unsigned long rate;
55 unsigned long req_rate;
56 unsigned long new_rate;
57 struct clk_core *new_parent;
58 struct clk_core *new_child;
59 unsigned long flags;
60 bool orphan;
61 unsigned int enable_count;
62 unsigned int prepare_count;
63 unsigned long min_rate;
64 unsigned long max_rate;
65 unsigned long accuracy;
66 int phase;
67 struct hlist_head children;
68 struct hlist_node child_node;
69 struct hlist_head clks;
70 unsigned int notifier_count;
71#ifdef CONFIG_DEBUG_FS
72 struct dentry *dentry;
73 struct hlist_node debug_node;
74#endif
75 struct kref ref;
76};
77
78#define CREATE_TRACE_POINTS
79#include <trace/events/clk.h>
80
81struct clk {
82 struct clk_core *core;
83 const char *dev_id;
84 const char *con_id;
85 unsigned long min_rate;
86 unsigned long max_rate;
87 struct hlist_node clks_node;
88};
89
90/*** locking ***/
91static void clk_prepare_lock(void)
92{
93 if (!mutex_trylock(&prepare_lock)) {
94 if (prepare_owner == current) {
95 prepare_refcnt++;
96 return;
97 }
98 mutex_lock(&prepare_lock);
99 }
100 WARN_ON_ONCE(prepare_owner != NULL);
101 WARN_ON_ONCE(prepare_refcnt != 0);
102 prepare_owner = current;
103 prepare_refcnt = 1;
104}
105
106static void clk_prepare_unlock(void)
107{
108 WARN_ON_ONCE(prepare_owner != current);
109 WARN_ON_ONCE(prepare_refcnt == 0);
110
111 if (--prepare_refcnt)
112 return;
113 prepare_owner = NULL;
114 mutex_unlock(&prepare_lock);
115}
116
117static unsigned long clk_enable_lock(void)
118 __acquires(enable_lock)
119{
120 unsigned long flags;
121
122 if (!spin_trylock_irqsave(&enable_lock, flags)) {
123 if (enable_owner == current) {
124 enable_refcnt++;
125 __acquire(enable_lock);
126 return flags;
127 }
128 spin_lock_irqsave(&enable_lock, flags);
129 }
130 WARN_ON_ONCE(enable_owner != NULL);
131 WARN_ON_ONCE(enable_refcnt != 0);
132 enable_owner = current;
133 enable_refcnt = 1;
134 return flags;
135}
136
137static void clk_enable_unlock(unsigned long flags)
138 __releases(enable_lock)
139{
140 WARN_ON_ONCE(enable_owner != current);
141 WARN_ON_ONCE(enable_refcnt == 0);
142
143 if (--enable_refcnt) {
144 __release(enable_lock);
145 return;
146 }
147 enable_owner = NULL;
148 spin_unlock_irqrestore(&enable_lock, flags);
149}
150
151static bool clk_core_is_prepared(struct clk_core *core)
152{
153 /*
154 * .is_prepared is optional for clocks that can prepare
155 * fall back to software usage counter if it is missing
156 */
157 if (!core->ops->is_prepared)
158 return core->prepare_count;
159
160 return core->ops->is_prepared(core->hw);
161}
162
163static bool clk_core_is_enabled(struct clk_core *core)
164{
165 /*
166 * .is_enabled is only mandatory for clocks that gate
167 * fall back to software usage counter if .is_enabled is missing
168 */
169 if (!core->ops->is_enabled)
170 return core->enable_count;
171
172 return core->ops->is_enabled(core->hw);
173}
174
175static void clk_unprepare_unused_subtree(struct clk_core *core)
176{
177 struct clk_core *child;
178
179 lockdep_assert_held(&prepare_lock);
180
181 hlist_for_each_entry(child, &core->children, child_node)
182 clk_unprepare_unused_subtree(child);
183
184 if (core->prepare_count)
185 return;
186
187 if (core->flags & CLK_IGNORE_UNUSED)
188 return;
189
190 if (clk_core_is_prepared(core)) {
191 trace_clk_unprepare(core);
192 if (core->ops->unprepare_unused)
193 core->ops->unprepare_unused(core->hw);
194 else if (core->ops->unprepare)
195 core->ops->unprepare(core->hw);
196 trace_clk_unprepare_complete(core);
197 }
198}
199
200static void clk_disable_unused_subtree(struct clk_core *core)
201{
202 struct clk_core *child;
203 unsigned long flags;
204
205 lockdep_assert_held(&prepare_lock);
206
207 hlist_for_each_entry(child, &core->children, child_node)
208 clk_disable_unused_subtree(child);
209
210 flags = clk_enable_lock();
211
212 if (core->enable_count)
213 goto unlock_out;
214
215 if (core->flags & CLK_IGNORE_UNUSED)
216 goto unlock_out;
217
218 /*
219 * some gate clocks have special needs during the disable-unused
220 * sequence. call .disable_unused if available, otherwise fall
221 * back to .disable
222 */
223 if (clk_core_is_enabled(core)) {
224 trace_clk_disable(core);
225 if (core->ops->disable_unused)
226 core->ops->disable_unused(core->hw);
227 else if (core->ops->disable)
228 core->ops->disable(core->hw);
229 trace_clk_disable_complete(core);
230 }
231
232unlock_out:
233 clk_enable_unlock(flags);
234}
235
236static bool clk_ignore_unused;
237static int __init clk_ignore_unused_setup(char *__unused)
238{
239 clk_ignore_unused = true;
240 return 1;
241}
242__setup("clk_ignore_unused", clk_ignore_unused_setup);
243
244static int clk_disable_unused(void)
245{
246 struct clk_core *core;
247
248 if (clk_ignore_unused) {
249 pr_warn("clk: Not disabling unused clocks\n");
250 return 0;
251 }
252
253 clk_prepare_lock();
254
255 hlist_for_each_entry(core, &clk_root_list, child_node)
256 clk_disable_unused_subtree(core);
257
258 hlist_for_each_entry(core, &clk_orphan_list, child_node)
259 clk_disable_unused_subtree(core);
260
261 hlist_for_each_entry(core, &clk_root_list, child_node)
262 clk_unprepare_unused_subtree(core);
263
264 hlist_for_each_entry(core, &clk_orphan_list, child_node)
265 clk_unprepare_unused_subtree(core);
266
267 clk_prepare_unlock();
268
269 return 0;
270}
271late_initcall_sync(clk_disable_unused);
272
273/*** helper functions ***/
274
275const char *__clk_get_name(const struct clk *clk)
276{
277 return !clk ? NULL : clk->core->name;
278}
279EXPORT_SYMBOL_GPL(__clk_get_name);
280
281const char *clk_hw_get_name(const struct clk_hw *hw)
282{
283 return hw->core->name;
284}
285EXPORT_SYMBOL_GPL(clk_hw_get_name);
286
287struct clk_hw *__clk_get_hw(struct clk *clk)
288{
289 return !clk ? NULL : clk->core->hw;
290}
291EXPORT_SYMBOL_GPL(__clk_get_hw);
292
293unsigned int clk_hw_get_num_parents(const struct clk_hw *hw)
294{
295 return hw->core->num_parents;
296}
297EXPORT_SYMBOL_GPL(clk_hw_get_num_parents);
298
299struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw)
300{
301 return hw->core->parent ? hw->core->parent->hw : NULL;
302}
303EXPORT_SYMBOL_GPL(clk_hw_get_parent);
304
305static struct clk_core *__clk_lookup_subtree(const char *name,
306 struct clk_core *core)
307{
308 struct clk_core *child;
309 struct clk_core *ret;
310
311 if (!strcmp(core->name, name))
312 return core;
313
314 hlist_for_each_entry(child, &core->children, child_node) {
315 ret = __clk_lookup_subtree(name, child);
316 if (ret)
317 return ret;
318 }
319
320 return NULL;
321}
322
323static struct clk_core *clk_core_lookup(const char *name)
324{
325 struct clk_core *root_clk;
326 struct clk_core *ret;
327
328 if (!name)
329 return NULL;
330
331 /* search the 'proper' clk tree first */
332 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
333 ret = __clk_lookup_subtree(name, root_clk);
334 if (ret)
335 return ret;
336 }
337
338 /* if not found, then search the orphan tree */
339 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
340 ret = __clk_lookup_subtree(name, root_clk);
341 if (ret)
342 return ret;
343 }
344
345 return NULL;
346}
347
348static struct clk_core *clk_core_get_parent_by_index(struct clk_core *core,
349 u8 index)
350{
351 if (!core || index >= core->num_parents)
352 return NULL;
353
354 if (!core->parents[index])
355 core->parents[index] =
356 clk_core_lookup(core->parent_names[index]);
357
358 return core->parents[index];
359}
360
361struct clk_hw *
362clk_hw_get_parent_by_index(const struct clk_hw *hw, unsigned int index)
363{
364 struct clk_core *parent;
365
366 parent = clk_core_get_parent_by_index(hw->core, index);
367
368 return !parent ? NULL : parent->hw;
369}
370EXPORT_SYMBOL_GPL(clk_hw_get_parent_by_index);
371
372unsigned int __clk_get_enable_count(struct clk *clk)
373{
374 return !clk ? 0 : clk->core->enable_count;
375}
376
377static unsigned long clk_core_get_rate_nolock(struct clk_core *core)
378{
379 unsigned long ret;
380
381 if (!core) {
382 ret = 0;
383 goto out;
384 }
385
386 ret = core->rate;
387
388 if (!core->num_parents)
389 goto out;
390
391 if (!core->parent)
392 ret = 0;
393
394out:
395 return ret;
396}
397
398unsigned long clk_hw_get_rate(const struct clk_hw *hw)
399{
400 return clk_core_get_rate_nolock(hw->core);
401}
402EXPORT_SYMBOL_GPL(clk_hw_get_rate);
403
404static unsigned long __clk_get_accuracy(struct clk_core *core)
405{
406 if (!core)
407 return 0;
408
409 return core->accuracy;
410}
411
412unsigned long __clk_get_flags(struct clk *clk)
413{
414 return !clk ? 0 : clk->core->flags;
415}
416EXPORT_SYMBOL_GPL(__clk_get_flags);
417
418unsigned long clk_hw_get_flags(const struct clk_hw *hw)
419{
420 return hw->core->flags;
421}
422EXPORT_SYMBOL_GPL(clk_hw_get_flags);
423
424bool clk_hw_is_prepared(const struct clk_hw *hw)
425{
426 return clk_core_is_prepared(hw->core);
427}
428
429bool clk_hw_is_enabled(const struct clk_hw *hw)
430{
431 return clk_core_is_enabled(hw->core);
432}
433
434bool __clk_is_enabled(struct clk *clk)
435{
436 if (!clk)
437 return false;
438
439 return clk_core_is_enabled(clk->core);
440}
441EXPORT_SYMBOL_GPL(__clk_is_enabled);
442
443static bool mux_is_better_rate(unsigned long rate, unsigned long now,
444 unsigned long best, unsigned long flags)
445{
446 if (flags & CLK_MUX_ROUND_CLOSEST)
447 return abs(now - rate) < abs(best - rate);
448
449 return now <= rate && now > best;
450}
451
452static int
453clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request *req,
454 unsigned long flags)
455{
456 struct clk_core *core = hw->core, *parent, *best_parent = NULL;
457 int i, num_parents, ret;
458 unsigned long best = 0;
459 struct clk_rate_request parent_req = *req;
460
461 /* if NO_REPARENT flag set, pass through to current parent */
462 if (core->flags & CLK_SET_RATE_NO_REPARENT) {
463 parent = core->parent;
464 if (core->flags & CLK_SET_RATE_PARENT) {
465 ret = __clk_determine_rate(parent ? parent->hw : NULL,
466 &parent_req);
467 if (ret)
468 return ret;
469
470 best = parent_req.rate;
471 } else if (parent) {
472 best = clk_core_get_rate_nolock(parent);
473 } else {
474 best = clk_core_get_rate_nolock(core);
475 }
476
477 goto out;
478 }
479
480 /* find the parent that can provide the fastest rate <= rate */
481 num_parents = core->num_parents;
482 for (i = 0; i < num_parents; i++) {
483 parent = clk_core_get_parent_by_index(core, i);
484 if (!parent)
485 continue;
486
487 if (core->flags & CLK_SET_RATE_PARENT) {
488 parent_req = *req;
489 ret = __clk_determine_rate(parent->hw, &parent_req);
490 if (ret)
491 continue;
492 } else {
493 parent_req.rate = clk_core_get_rate_nolock(parent);
494 }
495
496 if (mux_is_better_rate(req->rate, parent_req.rate,
497 best, flags)) {
498 best_parent = parent;
499 best = parent_req.rate;
500 }
501 }
502
503 if (!best_parent)
504 return -EINVAL;
505
506out:
507 if (best_parent)
508 req->best_parent_hw = best_parent->hw;
509 req->best_parent_rate = best;
510 req->rate = best;
511
512 return 0;
513}
514
515struct clk *__clk_lookup(const char *name)
516{
517 struct clk_core *core = clk_core_lookup(name);
518
519 return !core ? NULL : core->hw->clk;
520}
521
522static void clk_core_get_boundaries(struct clk_core *core,
523 unsigned long *min_rate,
524 unsigned long *max_rate)
525{
526 struct clk *clk_user;
527
528 *min_rate = core->min_rate;
529 *max_rate = core->max_rate;
530
531 hlist_for_each_entry(clk_user, &core->clks, clks_node)
532 *min_rate = max(*min_rate, clk_user->min_rate);
533
534 hlist_for_each_entry(clk_user, &core->clks, clks_node)
535 *max_rate = min(*max_rate, clk_user->max_rate);
536}
537
538void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
539 unsigned long max_rate)
540{
541 hw->core->min_rate = min_rate;
542 hw->core->max_rate = max_rate;
543}
544EXPORT_SYMBOL_GPL(clk_hw_set_rate_range);
545
546/*
547 * Helper for finding best parent to provide a given frequency. This can be used
548 * directly as a determine_rate callback (e.g. for a mux), or from a more
549 * complex clock that may combine a mux with other operations.
550 */
551int __clk_mux_determine_rate(struct clk_hw *hw,
552 struct clk_rate_request *req)
553{
554 return clk_mux_determine_rate_flags(hw, req, 0);
555}
556EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
557
558int __clk_mux_determine_rate_closest(struct clk_hw *hw,
559 struct clk_rate_request *req)
560{
561 return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST);
562}
563EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
564
565/*** clk api ***/
566
567static void clk_core_unprepare(struct clk_core *core)
568{
569 lockdep_assert_held(&prepare_lock);
570
571 if (!core)
572 return;
573
574 if (WARN_ON(core->prepare_count == 0))
575 return;
576
577 if (--core->prepare_count > 0)
578 return;
579
580 WARN_ON(core->enable_count > 0);
581
582 trace_clk_unprepare(core);
583
584 if (core->ops->unprepare)
585 core->ops->unprepare(core->hw);
586
587 trace_clk_unprepare_complete(core);
588 clk_core_unprepare(core->parent);
589}
590
591/**
592 * clk_unprepare - undo preparation of a clock source
593 * @clk: the clk being unprepared
594 *
595 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
596 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
597 * if the operation may sleep. One example is a clk which is accessed over
598 * I2c. In the complex case a clk gate operation may require a fast and a slow
599 * part. It is this reason that clk_unprepare and clk_disable are not mutually
600 * exclusive. In fact clk_disable must be called before clk_unprepare.
601 */
602void clk_unprepare(struct clk *clk)
603{
604 if (IS_ERR_OR_NULL(clk))
605 return;
606
607 clk_prepare_lock();
608 clk_core_unprepare(clk->core);
609 clk_prepare_unlock();
610}
611EXPORT_SYMBOL_GPL(clk_unprepare);
612
613static int clk_core_prepare(struct clk_core *core)
614{
615 int ret = 0;
616
617 lockdep_assert_held(&prepare_lock);
618
619 if (!core)
620 return 0;
621
622 if (core->prepare_count == 0) {
623 ret = clk_core_prepare(core->parent);
624 if (ret)
625 return ret;
626
627 trace_clk_prepare(core);
628
629 if (core->ops->prepare)
630 ret = core->ops->prepare(core->hw);
631
632 trace_clk_prepare_complete(core);
633
634 if (ret) {
635 clk_core_unprepare(core->parent);
636 return ret;
637 }
638 }
639
640 core->prepare_count++;
641
642 return 0;
643}
644
645/**
646 * clk_prepare - prepare a clock source
647 * @clk: the clk being prepared
648 *
649 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
650 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
651 * operation may sleep. One example is a clk which is accessed over I2c. In
652 * the complex case a clk ungate operation may require a fast and a slow part.
653 * It is this reason that clk_prepare and clk_enable are not mutually
654 * exclusive. In fact clk_prepare must be called before clk_enable.
655 * Returns 0 on success, -EERROR otherwise.
656 */
657int clk_prepare(struct clk *clk)
658{
659 int ret;
660
661 if (!clk)
662 return 0;
663
664 clk_prepare_lock();
665 ret = clk_core_prepare(clk->core);
666 clk_prepare_unlock();
667
668 return ret;
669}
670EXPORT_SYMBOL_GPL(clk_prepare);
671
672static void clk_core_disable(struct clk_core *core)
673{
674 lockdep_assert_held(&enable_lock);
675
676 if (!core)
677 return;
678
679 if (WARN_ON(core->enable_count == 0))
680 return;
681
682 if (--core->enable_count > 0)
683 return;
684
685 trace_clk_disable(core);
686
687 if (core->ops->disable)
688 core->ops->disable(core->hw);
689
690 trace_clk_disable_complete(core);
691
692 clk_core_disable(core->parent);
693}
694
695/**
696 * clk_disable - gate a clock
697 * @clk: the clk being gated
698 *
699 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
700 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
701 * clk if the operation is fast and will never sleep. One example is a
702 * SoC-internal clk which is controlled via simple register writes. In the
703 * complex case a clk gate operation may require a fast and a slow part. It is
704 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
705 * In fact clk_disable must be called before clk_unprepare.
706 */
707void clk_disable(struct clk *clk)
708{
709 unsigned long flags;
710
711 if (IS_ERR_OR_NULL(clk))
712 return;
713
714 flags = clk_enable_lock();
715 clk_core_disable(clk->core);
716 clk_enable_unlock(flags);
717}
718EXPORT_SYMBOL_GPL(clk_disable);
719
720static int clk_core_enable(struct clk_core *core)
721{
722 int ret = 0;
723
724 lockdep_assert_held(&enable_lock);
725
726 if (!core)
727 return 0;
728
729 if (WARN_ON(core->prepare_count == 0))
730 return -ESHUTDOWN;
731
732 if (core->enable_count == 0) {
733 ret = clk_core_enable(core->parent);
734
735 if (ret)
736 return ret;
737
738 trace_clk_enable(core);
739
740 if (core->ops->enable)
741 ret = core->ops->enable(core->hw);
742
743 trace_clk_enable_complete(core);
744
745 if (ret) {
746 clk_core_disable(core->parent);
747 return ret;
748 }
749 }
750
751 core->enable_count++;
752 return 0;
753}
754
755/**
756 * clk_enable - ungate a clock
757 * @clk: the clk being ungated
758 *
759 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
760 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
761 * if the operation will never sleep. One example is a SoC-internal clk which
762 * is controlled via simple register writes. In the complex case a clk ungate
763 * operation may require a fast and a slow part. It is this reason that
764 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
765 * must be called before clk_enable. Returns 0 on success, -EERROR
766 * otherwise.
767 */
768int clk_enable(struct clk *clk)
769{
770 unsigned long flags;
771 int ret;
772
773 if (!clk)
774 return 0;
775
776 flags = clk_enable_lock();
777 ret = clk_core_enable(clk->core);
778 clk_enable_unlock(flags);
779
780 return ret;
781}
782EXPORT_SYMBOL_GPL(clk_enable);
783
784static int clk_core_round_rate_nolock(struct clk_core *core,
785 struct clk_rate_request *req)
786{
787 struct clk_core *parent;
788 long rate;
789
790 lockdep_assert_held(&prepare_lock);
791
792 if (!core)
793 return 0;
794
795 parent = core->parent;
796 if (parent) {
797 req->best_parent_hw = parent->hw;
798 req->best_parent_rate = parent->rate;
799 } else {
800 req->best_parent_hw = NULL;
801 req->best_parent_rate = 0;
802 }
803
804 if (core->ops->determine_rate) {
805 return core->ops->determine_rate(core->hw, req);
806 } else if (core->ops->round_rate) {
807 rate = core->ops->round_rate(core->hw, req->rate,
808 &req->best_parent_rate);
809 if (rate < 0)
810 return rate;
811
812 req->rate = rate;
813 } else if (core->flags & CLK_SET_RATE_PARENT) {
814 return clk_core_round_rate_nolock(parent, req);
815 } else {
816 req->rate = core->rate;
817 }
818
819 return 0;
820}
821
822/**
823 * __clk_determine_rate - get the closest rate actually supported by a clock
824 * @hw: determine the rate of this clock
825 * @rate: target rate
826 * @min_rate: returned rate must be greater than this rate
827 * @max_rate: returned rate must be less than this rate
828 *
829 * Useful for clk_ops such as .set_rate and .determine_rate.
830 */
831int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
832{
833 if (!hw) {
834 req->rate = 0;
835 return 0;
836 }
837
838 return clk_core_round_rate_nolock(hw->core, req);
839}
840EXPORT_SYMBOL_GPL(__clk_determine_rate);
841
842unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate)
843{
844 int ret;
845 struct clk_rate_request req;
846
847 clk_core_get_boundaries(hw->core, &req.min_rate, &req.max_rate);
848 req.rate = rate;
849
850 ret = clk_core_round_rate_nolock(hw->core, &req);
851 if (ret)
852 return 0;
853
854 return req.rate;
855}
856EXPORT_SYMBOL_GPL(clk_hw_round_rate);
857
858/**
859 * clk_round_rate - round the given rate for a clk
860 * @clk: the clk for which we are rounding a rate
861 * @rate: the rate which is to be rounded
862 *
863 * Takes in a rate as input and rounds it to a rate that the clk can actually
864 * use which is then returned. If clk doesn't support round_rate operation
865 * then the parent rate is returned.
866 */
867long clk_round_rate(struct clk *clk, unsigned long rate)
868{
869 struct clk_rate_request req;
870 int ret;
871
872 if (!clk)
873 return 0;
874
875 clk_prepare_lock();
876
877 clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate);
878 req.rate = rate;
879
880 ret = clk_core_round_rate_nolock(clk->core, &req);
881 clk_prepare_unlock();
882
883 if (ret)
884 return ret;
885
886 return req.rate;
887}
888EXPORT_SYMBOL_GPL(clk_round_rate);
889
890/**
891 * __clk_notify - call clk notifier chain
892 * @core: clk that is changing rate
893 * @msg: clk notifier type (see include/linux/clk.h)
894 * @old_rate: old clk rate
895 * @new_rate: new clk rate
896 *
897 * Triggers a notifier call chain on the clk rate-change notification
898 * for 'clk'. Passes a pointer to the struct clk and the previous
899 * and current rates to the notifier callback. Intended to be called by
900 * internal clock code only. Returns NOTIFY_DONE from the last driver
901 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
902 * a driver returns that.
903 */
904static int __clk_notify(struct clk_core *core, unsigned long msg,
905 unsigned long old_rate, unsigned long new_rate)
906{
907 struct clk_notifier *cn;
908 struct clk_notifier_data cnd;
909 int ret = NOTIFY_DONE;
910
911 cnd.old_rate = old_rate;
912 cnd.new_rate = new_rate;
913
914 list_for_each_entry(cn, &clk_notifier_list, node) {
915 if (cn->clk->core == core) {
916 cnd.clk = cn->clk;
917 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
918 &cnd);
919 }
920 }
921
922 return ret;
923}
924
925/**
926 * __clk_recalc_accuracies
927 * @core: first clk in the subtree
928 *
929 * Walks the subtree of clks starting with clk and recalculates accuracies as
930 * it goes. Note that if a clk does not implement the .recalc_accuracy
931 * callback then it is assumed that the clock will take on the accuracy of its
932 * parent.
933 */
934static void __clk_recalc_accuracies(struct clk_core *core)
935{
936 unsigned long parent_accuracy = 0;
937 struct clk_core *child;
938
939 lockdep_assert_held(&prepare_lock);
940
941 if (core->parent)
942 parent_accuracy = core->parent->accuracy;
943
944 if (core->ops->recalc_accuracy)
945 core->accuracy = core->ops->recalc_accuracy(core->hw,
946 parent_accuracy);
947 else
948 core->accuracy = parent_accuracy;
949
950 hlist_for_each_entry(child, &core->children, child_node)
951 __clk_recalc_accuracies(child);
952}
953
954static long clk_core_get_accuracy(struct clk_core *core)
955{
956 unsigned long accuracy;
957
958 clk_prepare_lock();
959 if (core && (core->flags & CLK_GET_ACCURACY_NOCACHE))
960 __clk_recalc_accuracies(core);
961
962 accuracy = __clk_get_accuracy(core);
963 clk_prepare_unlock();
964
965 return accuracy;
966}
967
968/**
969 * clk_get_accuracy - return the accuracy of clk
970 * @clk: the clk whose accuracy is being returned
971 *
972 * Simply returns the cached accuracy of the clk, unless
973 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
974 * issued.
975 * If clk is NULL then returns 0.
976 */
977long clk_get_accuracy(struct clk *clk)
978{
979 if (!clk)
980 return 0;
981
982 return clk_core_get_accuracy(clk->core);
983}
984EXPORT_SYMBOL_GPL(clk_get_accuracy);
985
986static unsigned long clk_recalc(struct clk_core *core,
987 unsigned long parent_rate)
988{
989 if (core->ops->recalc_rate)
990 return core->ops->recalc_rate(core->hw, parent_rate);
991 return parent_rate;
992}
993
994/**
995 * __clk_recalc_rates
996 * @core: first clk in the subtree
997 * @msg: notification type (see include/linux/clk.h)
998 *
999 * Walks the subtree of clks starting with clk and recalculates rates as it
1000 * goes. Note that if a clk does not implement the .recalc_rate callback then
1001 * it is assumed that the clock will take on the rate of its parent.
1002 *
1003 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1004 * if necessary.
1005 */
1006static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
1007{
1008 unsigned long old_rate;
1009 unsigned long parent_rate = 0;
1010 struct clk_core *child;
1011
1012 lockdep_assert_held(&prepare_lock);
1013
1014 old_rate = core->rate;
1015
1016 if (core->parent)
1017 parent_rate = core->parent->rate;
1018
1019 core->rate = clk_recalc(core, parent_rate);
1020
1021 /*
1022 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1023 * & ABORT_RATE_CHANGE notifiers
1024 */
1025 if (core->notifier_count && msg)
1026 __clk_notify(core, msg, old_rate, core->rate);
1027
1028 hlist_for_each_entry(child, &core->children, child_node)
1029 __clk_recalc_rates(child, msg);
1030}
1031
1032static unsigned long clk_core_get_rate(struct clk_core *core)
1033{
1034 unsigned long rate;
1035
1036 clk_prepare_lock();
1037
1038 if (core && (core->flags & CLK_GET_RATE_NOCACHE))
1039 __clk_recalc_rates(core, 0);
1040
1041 rate = clk_core_get_rate_nolock(core);
1042 clk_prepare_unlock();
1043
1044 return rate;
1045}
1046
1047/**
1048 * clk_get_rate - return the rate of clk
1049 * @clk: the clk whose rate is being returned
1050 *
1051 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1052 * is set, which means a recalc_rate will be issued.
1053 * If clk is NULL then returns 0.
1054 */
1055unsigned long clk_get_rate(struct clk *clk)
1056{
1057 if (!clk)
1058 return 0;
1059
1060 return clk_core_get_rate(clk->core);
1061}
1062EXPORT_SYMBOL_GPL(clk_get_rate);
1063
1064static int clk_fetch_parent_index(struct clk_core *core,
1065 struct clk_core *parent)
1066{
1067 int i;
1068
1069 if (!parent)
1070 return -EINVAL;
1071
1072 for (i = 0; i < core->num_parents; i++)
1073 if (clk_core_get_parent_by_index(core, i) == parent)
1074 return i;
1075
1076 return -EINVAL;
1077}
1078
1079/*
1080 * Update the orphan status of @core and all its children.
1081 */
1082static void clk_core_update_orphan_status(struct clk_core *core, bool is_orphan)
1083{
1084 struct clk_core *child;
1085
1086 core->orphan = is_orphan;
1087
1088 hlist_for_each_entry(child, &core->children, child_node)
1089 clk_core_update_orphan_status(child, is_orphan);
1090}
1091
1092static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
1093{
1094 bool was_orphan = core->orphan;
1095
1096 hlist_del(&core->child_node);
1097
1098 if (new_parent) {
1099 bool becomes_orphan = new_parent->orphan;
1100
1101 /* avoid duplicate POST_RATE_CHANGE notifications */
1102 if (new_parent->new_child == core)
1103 new_parent->new_child = NULL;
1104
1105 hlist_add_head(&core->child_node, &new_parent->children);
1106
1107 if (was_orphan != becomes_orphan)
1108 clk_core_update_orphan_status(core, becomes_orphan);
1109 } else {
1110 hlist_add_head(&core->child_node, &clk_orphan_list);
1111 if (!was_orphan)
1112 clk_core_update_orphan_status(core, true);
1113 }
1114
1115 core->parent = new_parent;
1116}
1117
1118static struct clk_core *__clk_set_parent_before(struct clk_core *core,
1119 struct clk_core *parent)
1120{
1121 unsigned long flags;
1122 struct clk_core *old_parent = core->parent;
1123
1124 /*
1125 * Migrate prepare state between parents and prevent race with
1126 * clk_enable().
1127 *
1128 * If the clock is not prepared, then a race with
1129 * clk_enable/disable() is impossible since we already have the
1130 * prepare lock (future calls to clk_enable() need to be preceded by
1131 * a clk_prepare()).
1132 *
1133 * If the clock is prepared, migrate the prepared state to the new
1134 * parent and also protect against a race with clk_enable() by
1135 * forcing the clock and the new parent on. This ensures that all
1136 * future calls to clk_enable() are practically NOPs with respect to
1137 * hardware and software states.
1138 *
1139 * See also: Comment for clk_set_parent() below.
1140 */
1141 if (core->prepare_count) {
1142 clk_core_prepare(parent);
1143 flags = clk_enable_lock();
1144 clk_core_enable(parent);
1145 clk_core_enable(core);
1146 clk_enable_unlock(flags);
1147 }
1148
1149 /* update the clk tree topology */
1150 flags = clk_enable_lock();
1151 clk_reparent(core, parent);
1152 clk_enable_unlock(flags);
1153
1154 return old_parent;
1155}
1156
1157static void __clk_set_parent_after(struct clk_core *core,
1158 struct clk_core *parent,
1159 struct clk_core *old_parent)
1160{
1161 unsigned long flags;
1162
1163 /*
1164 * Finish the migration of prepare state and undo the changes done
1165 * for preventing a race with clk_enable().
1166 */
1167 if (core->prepare_count) {
1168 flags = clk_enable_lock();
1169 clk_core_disable(core);
1170 clk_core_disable(old_parent);
1171 clk_enable_unlock(flags);
1172 clk_core_unprepare(old_parent);
1173 }
1174}
1175
1176static int __clk_set_parent(struct clk_core *core, struct clk_core *parent,
1177 u8 p_index)
1178{
1179 unsigned long flags;
1180 int ret = 0;
1181 struct clk_core *old_parent;
1182
1183 old_parent = __clk_set_parent_before(core, parent);
1184
1185 trace_clk_set_parent(core, parent);
1186
1187 /* change clock input source */
1188 if (parent && core->ops->set_parent)
1189 ret = core->ops->set_parent(core->hw, p_index);
1190
1191 trace_clk_set_parent_complete(core, parent);
1192
1193 if (ret) {
1194 flags = clk_enable_lock();
1195 clk_reparent(core, old_parent);
1196 clk_enable_unlock(flags);
1197 __clk_set_parent_after(core, old_parent, parent);
1198
1199 return ret;
1200 }
1201
1202 __clk_set_parent_after(core, parent, old_parent);
1203
1204 return 0;
1205}
1206
1207/**
1208 * __clk_speculate_rates
1209 * @core: first clk in the subtree
1210 * @parent_rate: the "future" rate of clk's parent
1211 *
1212 * Walks the subtree of clks starting with clk, speculating rates as it
1213 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1214 *
1215 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1216 * pre-rate change notifications and returns early if no clks in the
1217 * subtree have subscribed to the notifications. Note that if a clk does not
1218 * implement the .recalc_rate callback then it is assumed that the clock will
1219 * take on the rate of its parent.
1220 */
1221static int __clk_speculate_rates(struct clk_core *core,
1222 unsigned long parent_rate)
1223{
1224 struct clk_core *child;
1225 unsigned long new_rate;
1226 int ret = NOTIFY_DONE;
1227
1228 lockdep_assert_held(&prepare_lock);
1229
1230 new_rate = clk_recalc(core, parent_rate);
1231
1232 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1233 if (core->notifier_count)
1234 ret = __clk_notify(core, PRE_RATE_CHANGE, core->rate, new_rate);
1235
1236 if (ret & NOTIFY_STOP_MASK) {
1237 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1238 __func__, core->name, ret);
1239 goto out;
1240 }
1241
1242 hlist_for_each_entry(child, &core->children, child_node) {
1243 ret = __clk_speculate_rates(child, new_rate);
1244 if (ret & NOTIFY_STOP_MASK)
1245 break;
1246 }
1247
1248out:
1249 return ret;
1250}
1251
1252static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate,
1253 struct clk_core *new_parent, u8 p_index)
1254{
1255 struct clk_core *child;
1256
1257 core->new_rate = new_rate;
1258 core->new_parent = new_parent;
1259 core->new_parent_index = p_index;
1260 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1261 core->new_child = NULL;
1262 if (new_parent && new_parent != core->parent)
1263 new_parent->new_child = core;
1264
1265 hlist_for_each_entry(child, &core->children, child_node) {
1266 child->new_rate = clk_recalc(child, new_rate);
1267 clk_calc_subtree(child, child->new_rate, NULL, 0);
1268 }
1269}
1270
1271/*
1272 * calculate the new rates returning the topmost clock that has to be
1273 * changed.
1274 */
1275static struct clk_core *clk_calc_new_rates(struct clk_core *core,
1276 unsigned long rate)
1277{
1278 struct clk_core *top = core;
1279 struct clk_core *old_parent, *parent;
1280 unsigned long best_parent_rate = 0;
1281 unsigned long new_rate;
1282 unsigned long min_rate;
1283 unsigned long max_rate;
1284 int p_index = 0;
1285 long ret;
1286
1287 /* sanity */
1288 if (IS_ERR_OR_NULL(core))
1289 return NULL;
1290
1291 /* save parent rate, if it exists */
1292 parent = old_parent = core->parent;
1293 if (parent)
1294 best_parent_rate = parent->rate;
1295
1296 clk_core_get_boundaries(core, &min_rate, &max_rate);
1297
1298 /* find the closest rate and parent clk/rate */
1299 if (core->ops->determine_rate) {
1300 struct clk_rate_request req;
1301
1302 req.rate = rate;
1303 req.min_rate = min_rate;
1304 req.max_rate = max_rate;
1305 if (parent) {
1306 req.best_parent_hw = parent->hw;
1307 req.best_parent_rate = parent->rate;
1308 } else {
1309 req.best_parent_hw = NULL;
1310 req.best_parent_rate = 0;
1311 }
1312
1313 ret = core->ops->determine_rate(core->hw, &req);
1314 if (ret < 0)
1315 return NULL;
1316
1317 best_parent_rate = req.best_parent_rate;
1318 new_rate = req.rate;
1319 parent = req.best_parent_hw ? req.best_parent_hw->core : NULL;
1320 } else if (core->ops->round_rate) {
1321 ret = core->ops->round_rate(core->hw, rate,
1322 &best_parent_rate);
1323 if (ret < 0)
1324 return NULL;
1325
1326 new_rate = ret;
1327 if (new_rate < min_rate || new_rate > max_rate)
1328 return NULL;
1329 } else if (!parent || !(core->flags & CLK_SET_RATE_PARENT)) {
1330 /* pass-through clock without adjustable parent */
1331 core->new_rate = core->rate;
1332 return NULL;
1333 } else {
1334 /* pass-through clock with adjustable parent */
1335 top = clk_calc_new_rates(parent, rate);
1336 new_rate = parent->new_rate;
1337 goto out;
1338 }
1339
1340 /* some clocks must be gated to change parent */
1341 if (parent != old_parent &&
1342 (core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
1343 pr_debug("%s: %s not gated but wants to reparent\n",
1344 __func__, core->name);
1345 return NULL;
1346 }
1347
1348 /* try finding the new parent index */
1349 if (parent && core->num_parents > 1) {
1350 p_index = clk_fetch_parent_index(core, parent);
1351 if (p_index < 0) {
1352 pr_debug("%s: clk %s can not be parent of clk %s\n",
1353 __func__, parent->name, core->name);
1354 return NULL;
1355 }
1356 }
1357
1358 if ((core->flags & CLK_SET_RATE_PARENT) && parent &&
1359 best_parent_rate != parent->rate)
1360 top = clk_calc_new_rates(parent, best_parent_rate);
1361
1362out:
1363 clk_calc_subtree(core, new_rate, parent, p_index);
1364
1365 return top;
1366}
1367
1368/*
1369 * Notify about rate changes in a subtree. Always walk down the whole tree
1370 * so that in case of an error we can walk down the whole tree again and
1371 * abort the change.
1372 */
1373static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
1374 unsigned long event)
1375{
1376 struct clk_core *child, *tmp_clk, *fail_clk = NULL;
1377 int ret = NOTIFY_DONE;
1378
1379 if (core->rate == core->new_rate)
1380 return NULL;
1381
1382 if (core->notifier_count) {
1383 ret = __clk_notify(core, event, core->rate, core->new_rate);
1384 if (ret & NOTIFY_STOP_MASK)
1385 fail_clk = core;
1386 }
1387
1388 hlist_for_each_entry(child, &core->children, child_node) {
1389 /* Skip children who will be reparented to another clock */
1390 if (child->new_parent && child->new_parent != core)
1391 continue;
1392 tmp_clk = clk_propagate_rate_change(child, event);
1393 if (tmp_clk)
1394 fail_clk = tmp_clk;
1395 }
1396
1397 /* handle the new child who might not be in core->children yet */
1398 if (core->new_child) {
1399 tmp_clk = clk_propagate_rate_change(core->new_child, event);
1400 if (tmp_clk)
1401 fail_clk = tmp_clk;
1402 }
1403
1404 return fail_clk;
1405}
1406
1407/*
1408 * walk down a subtree and set the new rates notifying the rate
1409 * change on the way
1410 */
1411static void clk_change_rate(struct clk_core *core)
1412{
1413 struct clk_core *child;
1414 struct hlist_node *tmp;
1415 unsigned long old_rate;
1416 unsigned long best_parent_rate = 0;
1417 bool skip_set_rate = false;
1418 struct clk_core *old_parent;
1419
1420 old_rate = core->rate;
1421
1422 if (core->new_parent)
1423 best_parent_rate = core->new_parent->rate;
1424 else if (core->parent)
1425 best_parent_rate = core->parent->rate;
1426
1427 if (core->flags & CLK_SET_RATE_UNGATE) {
1428 unsigned long flags;
1429
1430 clk_core_prepare(core);
1431 flags = clk_enable_lock();
1432 clk_core_enable(core);
1433 clk_enable_unlock(flags);
1434 }
1435
1436 if (core->new_parent && core->new_parent != core->parent) {
1437 old_parent = __clk_set_parent_before(core, core->new_parent);
1438 trace_clk_set_parent(core, core->new_parent);
1439
1440 if (core->ops->set_rate_and_parent) {
1441 skip_set_rate = true;
1442 core->ops->set_rate_and_parent(core->hw, core->new_rate,
1443 best_parent_rate,
1444 core->new_parent_index);
1445 } else if (core->ops->set_parent) {
1446 core->ops->set_parent(core->hw, core->new_parent_index);
1447 }
1448
1449 trace_clk_set_parent_complete(core, core->new_parent);
1450 __clk_set_parent_after(core, core->new_parent, old_parent);
1451 }
1452
1453 trace_clk_set_rate(core, core->new_rate);
1454
1455 if (!skip_set_rate && core->ops->set_rate)
1456 core->ops->set_rate(core->hw, core->new_rate, best_parent_rate);
1457
1458 trace_clk_set_rate_complete(core, core->new_rate);
1459
1460 core->rate = clk_recalc(core, best_parent_rate);
1461
1462 if (core->flags & CLK_SET_RATE_UNGATE) {
1463 unsigned long flags;
1464
1465 flags = clk_enable_lock();
1466 clk_core_disable(core);
1467 clk_enable_unlock(flags);
1468 clk_core_unprepare(core);
1469 }
1470
1471 if (core->notifier_count && old_rate != core->rate)
1472 __clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate);
1473
1474 if (core->flags & CLK_RECALC_NEW_RATES)
1475 (void)clk_calc_new_rates(core, core->new_rate);
1476
1477 /*
1478 * Use safe iteration, as change_rate can actually swap parents
1479 * for certain clock types.
1480 */
1481 hlist_for_each_entry_safe(child, tmp, &core->children, child_node) {
1482 /* Skip children who will be reparented to another clock */
1483 if (child->new_parent && child->new_parent != core)
1484 continue;
1485 clk_change_rate(child);
1486 }
1487
1488 /* handle the new child who might not be in core->children yet */
1489 if (core->new_child)
1490 clk_change_rate(core->new_child);
1491}
1492
1493static int clk_core_set_rate_nolock(struct clk_core *core,
1494 unsigned long req_rate)
1495{
1496 struct clk_core *top, *fail_clk;
1497 unsigned long rate = req_rate;
1498 int ret = 0;
1499
1500 if (!core)
1501 return 0;
1502
1503 /* bail early if nothing to do */
1504 if (rate == clk_core_get_rate_nolock(core))
1505 return 0;
1506
1507 if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
1508 return -EBUSY;
1509
1510 /* calculate new rates and get the topmost changed clock */
1511 top = clk_calc_new_rates(core, rate);
1512 if (!top)
1513 return -EINVAL;
1514
1515 /* notify that we are about to change rates */
1516 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1517 if (fail_clk) {
1518 pr_debug("%s: failed to set %s rate\n", __func__,
1519 fail_clk->name);
1520 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1521 return -EBUSY;
1522 }
1523
1524 /* change the rates */
1525 clk_change_rate(top);
1526
1527 core->req_rate = req_rate;
1528
1529 return ret;
1530}
1531
1532/**
1533 * clk_set_rate - specify a new rate for clk
1534 * @clk: the clk whose rate is being changed
1535 * @rate: the new rate for clk
1536 *
1537 * In the simplest case clk_set_rate will only adjust the rate of clk.
1538 *
1539 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1540 * propagate up to clk's parent; whether or not this happens depends on the
1541 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1542 * after calling .round_rate then upstream parent propagation is ignored. If
1543 * *parent_rate comes back with a new rate for clk's parent then we propagate
1544 * up to clk's parent and set its rate. Upward propagation will continue
1545 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1546 * .round_rate stops requesting changes to clk's parent_rate.
1547 *
1548 * Rate changes are accomplished via tree traversal that also recalculates the
1549 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1550 *
1551 * Returns 0 on success, -EERROR otherwise.
1552 */
1553int clk_set_rate(struct clk *clk, unsigned long rate)
1554{
1555 int ret;
1556
1557 if (!clk)
1558 return 0;
1559
1560 /* prevent racing with updates to the clock topology */
1561 clk_prepare_lock();
1562
1563 ret = clk_core_set_rate_nolock(clk->core, rate);
1564
1565 clk_prepare_unlock();
1566
1567 return ret;
1568}
1569EXPORT_SYMBOL_GPL(clk_set_rate);
1570
1571/**
1572 * clk_set_rate_range - set a rate range for a clock source
1573 * @clk: clock source
1574 * @min: desired minimum clock rate in Hz, inclusive
1575 * @max: desired maximum clock rate in Hz, inclusive
1576 *
1577 * Returns success (0) or negative errno.
1578 */
1579int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
1580{
1581 int ret = 0;
1582
1583 if (!clk)
1584 return 0;
1585
1586 if (min > max) {
1587 pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
1588 __func__, clk->core->name, clk->dev_id, clk->con_id,
1589 min, max);
1590 return -EINVAL;
1591 }
1592
1593 clk_prepare_lock();
1594
1595 if (min != clk->min_rate || max != clk->max_rate) {
1596 clk->min_rate = min;
1597 clk->max_rate = max;
1598 ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
1599 }
1600
1601 clk_prepare_unlock();
1602
1603 return ret;
1604}
1605EXPORT_SYMBOL_GPL(clk_set_rate_range);
1606
1607/**
1608 * clk_set_min_rate - set a minimum clock rate for a clock source
1609 * @clk: clock source
1610 * @rate: desired minimum clock rate in Hz, inclusive
1611 *
1612 * Returns success (0) or negative errno.
1613 */
1614int clk_set_min_rate(struct clk *clk, unsigned long rate)
1615{
1616 if (!clk)
1617 return 0;
1618
1619 return clk_set_rate_range(clk, rate, clk->max_rate);
1620}
1621EXPORT_SYMBOL_GPL(clk_set_min_rate);
1622
1623/**
1624 * clk_set_max_rate - set a maximum clock rate for a clock source
1625 * @clk: clock source
1626 * @rate: desired maximum clock rate in Hz, inclusive
1627 *
1628 * Returns success (0) or negative errno.
1629 */
1630int clk_set_max_rate(struct clk *clk, unsigned long rate)
1631{
1632 if (!clk)
1633 return 0;
1634
1635 return clk_set_rate_range(clk, clk->min_rate, rate);
1636}
1637EXPORT_SYMBOL_GPL(clk_set_max_rate);
1638
1639/**
1640 * clk_get_parent - return the parent of a clk
1641 * @clk: the clk whose parent gets returned
1642 *
1643 * Simply returns clk->parent. Returns NULL if clk is NULL.
1644 */
1645struct clk *clk_get_parent(struct clk *clk)
1646{
1647 struct clk *parent;
1648
1649 if (!clk)
1650 return NULL;
1651
1652 clk_prepare_lock();
1653 /* TODO: Create a per-user clk and change callers to call clk_put */
1654 parent = !clk->core->parent ? NULL : clk->core->parent->hw->clk;
1655 clk_prepare_unlock();
1656
1657 return parent;
1658}
1659EXPORT_SYMBOL_GPL(clk_get_parent);
1660
1661static struct clk_core *__clk_init_parent(struct clk_core *core)
1662{
1663 u8 index = 0;
1664
1665 if (core->num_parents > 1 && core->ops->get_parent)
1666 index = core->ops->get_parent(core->hw);
1667
1668 return clk_core_get_parent_by_index(core, index);
1669}
1670
1671static void clk_core_reparent(struct clk_core *core,
1672 struct clk_core *new_parent)
1673{
1674 clk_reparent(core, new_parent);
1675 __clk_recalc_accuracies(core);
1676 __clk_recalc_rates(core, POST_RATE_CHANGE);
1677}
1678
1679void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
1680{
1681 if (!hw)
1682 return;
1683
1684 clk_core_reparent(hw->core, !new_parent ? NULL : new_parent->core);
1685}
1686
1687/**
1688 * clk_has_parent - check if a clock is a possible parent for another
1689 * @clk: clock source
1690 * @parent: parent clock source
1691 *
1692 * This function can be used in drivers that need to check that a clock can be
1693 * the parent of another without actually changing the parent.
1694 *
1695 * Returns true if @parent is a possible parent for @clk, false otherwise.
1696 */
1697bool clk_has_parent(struct clk *clk, struct clk *parent)
1698{
1699 struct clk_core *core, *parent_core;
1700 unsigned int i;
1701
1702 /* NULL clocks should be nops, so return success if either is NULL. */
1703 if (!clk || !parent)
1704 return true;
1705
1706 core = clk->core;
1707 parent_core = parent->core;
1708
1709 /* Optimize for the case where the parent is already the parent. */
1710 if (core->parent == parent_core)
1711 return true;
1712
1713 for (i = 0; i < core->num_parents; i++)
1714 if (strcmp(core->parent_names[i], parent_core->name) == 0)
1715 return true;
1716
1717 return false;
1718}
1719EXPORT_SYMBOL_GPL(clk_has_parent);
1720
1721static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
1722{
1723 int ret = 0;
1724 int p_index = 0;
1725 unsigned long p_rate = 0;
1726
1727 if (!core)
1728 return 0;
1729
1730 /* prevent racing with updates to the clock topology */
1731 clk_prepare_lock();
1732
1733 if (core->parent == parent)
1734 goto out;
1735
1736 /* verify ops for for multi-parent clks */
1737 if ((core->num_parents > 1) && (!core->ops->set_parent)) {
1738 ret = -ENOSYS;
1739 goto out;
1740 }
1741
1742 /* check that we are allowed to re-parent if the clock is in use */
1743 if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
1744 ret = -EBUSY;
1745 goto out;
1746 }
1747
1748 /* try finding the new parent index */
1749 if (parent) {
1750 p_index = clk_fetch_parent_index(core, parent);
1751 if (p_index < 0) {
1752 pr_debug("%s: clk %s can not be parent of clk %s\n",
1753 __func__, parent->name, core->name);
1754 ret = p_index;
1755 goto out;
1756 }
1757 p_rate = parent->rate;
1758 }
1759
1760 /* propagate PRE_RATE_CHANGE notifications */
1761 ret = __clk_speculate_rates(core, p_rate);
1762
1763 /* abort if a driver objects */
1764 if (ret & NOTIFY_STOP_MASK)
1765 goto out;
1766
1767 /* do the re-parent */
1768 ret = __clk_set_parent(core, parent, p_index);
1769
1770 /* propagate rate an accuracy recalculation accordingly */
1771 if (ret) {
1772 __clk_recalc_rates(core, ABORT_RATE_CHANGE);
1773 } else {
1774 __clk_recalc_rates(core, POST_RATE_CHANGE);
1775 __clk_recalc_accuracies(core);
1776 }
1777
1778out:
1779 clk_prepare_unlock();
1780
1781 return ret;
1782}
1783
1784/**
1785 * clk_set_parent - switch the parent of a mux clk
1786 * @clk: the mux clk whose input we are switching
1787 * @parent: the new input to clk
1788 *
1789 * Re-parent clk to use parent as its new input source. If clk is in
1790 * prepared state, the clk will get enabled for the duration of this call. If
1791 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1792 * that, the reparenting is glitchy in hardware, etc), use the
1793 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1794 *
1795 * After successfully changing clk's parent clk_set_parent will update the
1796 * clk topology, sysfs topology and propagate rate recalculation via
1797 * __clk_recalc_rates.
1798 *
1799 * Returns 0 on success, -EERROR otherwise.
1800 */
1801int clk_set_parent(struct clk *clk, struct clk *parent)
1802{
1803 if (!clk)
1804 return 0;
1805
1806 return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
1807}
1808EXPORT_SYMBOL_GPL(clk_set_parent);
1809
1810/**
1811 * clk_set_phase - adjust the phase shift of a clock signal
1812 * @clk: clock signal source
1813 * @degrees: number of degrees the signal is shifted
1814 *
1815 * Shifts the phase of a clock signal by the specified
1816 * degrees. Returns 0 on success, -EERROR otherwise.
1817 *
1818 * This function makes no distinction about the input or reference
1819 * signal that we adjust the clock signal phase against. For example
1820 * phase locked-loop clock signal generators we may shift phase with
1821 * respect to feedback clock signal input, but for other cases the
1822 * clock phase may be shifted with respect to some other, unspecified
1823 * signal.
1824 *
1825 * Additionally the concept of phase shift does not propagate through
1826 * the clock tree hierarchy, which sets it apart from clock rates and
1827 * clock accuracy. A parent clock phase attribute does not have an
1828 * impact on the phase attribute of a child clock.
1829 */
1830int clk_set_phase(struct clk *clk, int degrees)
1831{
1832 int ret = -EINVAL;
1833
1834 if (!clk)
1835 return 0;
1836
1837 /* sanity check degrees */
1838 degrees %= 360;
1839 if (degrees < 0)
1840 degrees += 360;
1841
1842 clk_prepare_lock();
1843
1844 /* bail early if nothing to do */
1845 if (degrees == clk->core->phase)
1846 goto out;
1847
1848 trace_clk_set_phase(clk->core, degrees);
1849
1850 if (clk->core->ops->set_phase)
1851 ret = clk->core->ops->set_phase(clk->core->hw, degrees);
1852
1853 trace_clk_set_phase_complete(clk->core, degrees);
1854
1855 if (!ret)
1856 clk->core->phase = degrees;
1857
1858out:
1859 clk_prepare_unlock();
1860
1861 return ret;
1862}
1863EXPORT_SYMBOL_GPL(clk_set_phase);
1864
1865static int clk_core_get_phase(struct clk_core *core)
1866{
1867 int ret;
1868
1869 clk_prepare_lock();
1870 ret = core->phase;
1871 clk_prepare_unlock();
1872
1873 return ret;
1874}
1875
1876/**
1877 * clk_get_phase - return the phase shift of a clock signal
1878 * @clk: clock signal source
1879 *
1880 * Returns the phase shift of a clock node in degrees, otherwise returns
1881 * -EERROR.
1882 */
1883int clk_get_phase(struct clk *clk)
1884{
1885 if (!clk)
1886 return 0;
1887
1888 return clk_core_get_phase(clk->core);
1889}
1890EXPORT_SYMBOL_GPL(clk_get_phase);
1891
1892/**
1893 * clk_is_match - check if two clk's point to the same hardware clock
1894 * @p: clk compared against q
1895 * @q: clk compared against p
1896 *
1897 * Returns true if the two struct clk pointers both point to the same hardware
1898 * clock node. Put differently, returns true if struct clk *p and struct clk *q
1899 * share the same struct clk_core object.
1900 *
1901 * Returns false otherwise. Note that two NULL clks are treated as matching.
1902 */
1903bool clk_is_match(const struct clk *p, const struct clk *q)
1904{
1905 /* trivial case: identical struct clk's or both NULL */
1906 if (p == q)
1907 return true;
1908
1909 /* true if clk->core pointers match. Avoid dereferencing garbage */
1910 if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q))
1911 if (p->core == q->core)
1912 return true;
1913
1914 return false;
1915}
1916EXPORT_SYMBOL_GPL(clk_is_match);
1917
1918/*** debugfs support ***/
1919
1920#ifdef CONFIG_DEBUG_FS
1921#include <linux/debugfs.h>
1922
1923static struct dentry *rootdir;
1924static int inited = 0;
1925static DEFINE_MUTEX(clk_debug_lock);
1926static HLIST_HEAD(clk_debug_list);
1927
1928static struct hlist_head *all_lists[] = {
1929 &clk_root_list,
1930 &clk_orphan_list,
1931 NULL,
1932};
1933
1934static struct hlist_head *orphan_list[] = {
1935 &clk_orphan_list,
1936 NULL,
1937};
1938
1939static void clk_summary_show_one(struct seq_file *s, struct clk_core *c,
1940 int level)
1941{
1942 if (!c)
1943 return;
1944
1945 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
1946 level * 3 + 1, "",
1947 30 - level * 3, c->name,
1948 c->enable_count, c->prepare_count, clk_core_get_rate(c),
1949 clk_core_get_accuracy(c), clk_core_get_phase(c));
1950}
1951
1952static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
1953 int level)
1954{
1955 struct clk_core *child;
1956
1957 if (!c)
1958 return;
1959
1960 clk_summary_show_one(s, c, level);
1961
1962 hlist_for_each_entry(child, &c->children, child_node)
1963 clk_summary_show_subtree(s, child, level + 1);
1964}
1965
1966static int clk_summary_show(struct seq_file *s, void *data)
1967{
1968 struct clk_core *c;
1969 struct hlist_head **lists = (struct hlist_head **)s->private;
1970
1971 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
1972 seq_puts(s, "----------------------------------------------------------------------------------------\n");
1973
1974 clk_prepare_lock();
1975
1976 for (; *lists; lists++)
1977 hlist_for_each_entry(c, *lists, child_node)
1978 clk_summary_show_subtree(s, c, 0);
1979
1980 clk_prepare_unlock();
1981
1982 return 0;
1983}
1984
1985
1986static int clk_summary_open(struct inode *inode, struct file *file)
1987{
1988 return single_open(file, clk_summary_show, inode->i_private);
1989}
1990
1991static const struct file_operations clk_summary_fops = {
1992 .open = clk_summary_open,
1993 .read = seq_read,
1994 .llseek = seq_lseek,
1995 .release = single_release,
1996};
1997
1998static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
1999{
2000 if (!c)
2001 return;
2002
2003 /* This should be JSON format, i.e. elements separated with a comma */
2004 seq_printf(s, "\"%s\": { ", c->name);
2005 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
2006 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
2007 seq_printf(s, "\"rate\": %lu,", clk_core_get_rate(c));
2008 seq_printf(s, "\"accuracy\": %lu,", clk_core_get_accuracy(c));
2009 seq_printf(s, "\"phase\": %d", clk_core_get_phase(c));
2010}
2011
2012static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level)
2013{
2014 struct clk_core *child;
2015
2016 if (!c)
2017 return;
2018
2019 clk_dump_one(s, c, level);
2020
2021 hlist_for_each_entry(child, &c->children, child_node) {
2022 seq_printf(s, ",");
2023 clk_dump_subtree(s, child, level + 1);
2024 }
2025
2026 seq_printf(s, "}");
2027}
2028
2029static int clk_dump(struct seq_file *s, void *data)
2030{
2031 struct clk_core *c;
2032 bool first_node = true;
2033 struct hlist_head **lists = (struct hlist_head **)s->private;
2034
2035 seq_printf(s, "{");
2036
2037 clk_prepare_lock();
2038
2039 for (; *lists; lists++) {
2040 hlist_for_each_entry(c, *lists, child_node) {
2041 if (!first_node)
2042 seq_puts(s, ",");
2043 first_node = false;
2044 clk_dump_subtree(s, c, 0);
2045 }
2046 }
2047
2048 clk_prepare_unlock();
2049
2050 seq_puts(s, "}\n");
2051 return 0;
2052}
2053
2054
2055static int clk_dump_open(struct inode *inode, struct file *file)
2056{
2057 return single_open(file, clk_dump, inode->i_private);
2058}
2059
2060static const struct file_operations clk_dump_fops = {
2061 .open = clk_dump_open,
2062 .read = seq_read,
2063 .llseek = seq_lseek,
2064 .release = single_release,
2065};
2066
2067static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
2068{
2069 struct dentry *d;
2070 int ret = -ENOMEM;
2071
2072 if (!core || !pdentry) {
2073 ret = -EINVAL;
2074 goto out;
2075 }
2076
2077 d = debugfs_create_dir(core->name, pdentry);
2078 if (!d)
2079 goto out;
2080
2081 core->dentry = d;
2082
2083 d = debugfs_create_u32("clk_rate", S_IRUGO, core->dentry,
2084 (u32 *)&core->rate);
2085 if (!d)
2086 goto err_out;
2087
2088 d = debugfs_create_u32("clk_accuracy", S_IRUGO, core->dentry,
2089 (u32 *)&core->accuracy);
2090 if (!d)
2091 goto err_out;
2092
2093 d = debugfs_create_u32("clk_phase", S_IRUGO, core->dentry,
2094 (u32 *)&core->phase);
2095 if (!d)
2096 goto err_out;
2097
2098 d = debugfs_create_x32("clk_flags", S_IRUGO, core->dentry,
2099 (u32 *)&core->flags);
2100 if (!d)
2101 goto err_out;
2102
2103 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, core->dentry,
2104 (u32 *)&core->prepare_count);
2105 if (!d)
2106 goto err_out;
2107
2108 d = debugfs_create_u32("clk_enable_count", S_IRUGO, core->dentry,
2109 (u32 *)&core->enable_count);
2110 if (!d)
2111 goto err_out;
2112
2113 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, core->dentry,
2114 (u32 *)&core->notifier_count);
2115 if (!d)
2116 goto err_out;
2117
2118 if (core->ops->debug_init) {
2119 ret = core->ops->debug_init(core->hw, core->dentry);
2120 if (ret)
2121 goto err_out;
2122 }
2123
2124 ret = 0;
2125 goto out;
2126
2127err_out:
2128 debugfs_remove_recursive(core->dentry);
2129 core->dentry = NULL;
2130out:
2131 return ret;
2132}
2133
2134/**
2135 * clk_debug_register - add a clk node to the debugfs clk directory
2136 * @core: the clk being added to the debugfs clk directory
2137 *
2138 * Dynamically adds a clk to the debugfs clk directory if debugfs has been
2139 * initialized. Otherwise it bails out early since the debugfs clk directory
2140 * will be created lazily by clk_debug_init as part of a late_initcall.
2141 */
2142static int clk_debug_register(struct clk_core *core)
2143{
2144 int ret = 0;
2145
2146 mutex_lock(&clk_debug_lock);
2147 hlist_add_head(&core->debug_node, &clk_debug_list);
2148
2149 if (!inited)
2150 goto unlock;
2151
2152 ret = clk_debug_create_one(core, rootdir);
2153unlock:
2154 mutex_unlock(&clk_debug_lock);
2155
2156 return ret;
2157}
2158
2159 /**
2160 * clk_debug_unregister - remove a clk node from the debugfs clk directory
2161 * @core: the clk being removed from the debugfs clk directory
2162 *
2163 * Dynamically removes a clk and all its child nodes from the
2164 * debugfs clk directory if clk->dentry points to debugfs created by
2165 * clk_debug_register in __clk_core_init.
2166 */
2167static void clk_debug_unregister(struct clk_core *core)
2168{
2169 mutex_lock(&clk_debug_lock);
2170 hlist_del_init(&core->debug_node);
2171 debugfs_remove_recursive(core->dentry);
2172 core->dentry = NULL;
2173 mutex_unlock(&clk_debug_lock);
2174}
2175
2176struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
2177 void *data, const struct file_operations *fops)
2178{
2179 struct dentry *d = NULL;
2180
2181 if (hw->core->dentry)
2182 d = debugfs_create_file(name, mode, hw->core->dentry, data,
2183 fops);
2184
2185 return d;
2186}
2187EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
2188
2189/**
2190 * clk_debug_init - lazily populate the debugfs clk directory
2191 *
2192 * clks are often initialized very early during boot before memory can be
2193 * dynamically allocated and well before debugfs is setup. This function
2194 * populates the debugfs clk directory once at boot-time when we know that
2195 * debugfs is setup. It should only be called once at boot-time, all other clks
2196 * added dynamically will be done so with clk_debug_register.
2197 */
2198static int __init clk_debug_init(void)
2199{
2200 struct clk_core *core;
2201 struct dentry *d;
2202
2203 rootdir = debugfs_create_dir("clk", NULL);
2204
2205 if (!rootdir)
2206 return -ENOMEM;
2207
2208 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
2209 &clk_summary_fops);
2210 if (!d)
2211 return -ENOMEM;
2212
2213 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
2214 &clk_dump_fops);
2215 if (!d)
2216 return -ENOMEM;
2217
2218 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
2219 &orphan_list, &clk_summary_fops);
2220 if (!d)
2221 return -ENOMEM;
2222
2223 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
2224 &orphan_list, &clk_dump_fops);
2225 if (!d)
2226 return -ENOMEM;
2227
2228 mutex_lock(&clk_debug_lock);
2229 hlist_for_each_entry(core, &clk_debug_list, debug_node)
2230 clk_debug_create_one(core, rootdir);
2231
2232 inited = 1;
2233 mutex_unlock(&clk_debug_lock);
2234
2235 return 0;
2236}
2237late_initcall(clk_debug_init);
2238#else
2239static inline int clk_debug_register(struct clk_core *core) { return 0; }
2240static inline void clk_debug_reparent(struct clk_core *core,
2241 struct clk_core *new_parent)
2242{
2243}
2244static inline void clk_debug_unregister(struct clk_core *core)
2245{
2246}
2247#endif
2248
2249/**
2250 * __clk_core_init - initialize the data structures in a struct clk_core
2251 * @core: clk_core being initialized
2252 *
2253 * Initializes the lists in struct clk_core, queries the hardware for the
2254 * parent and rate and sets them both.
2255 */
2256static int __clk_core_init(struct clk_core *core)
2257{
2258 int i, ret = 0;
2259 struct clk_core *orphan;
2260 struct hlist_node *tmp2;
2261 unsigned long rate;
2262
2263 if (!core)
2264 return -EINVAL;
2265
2266 clk_prepare_lock();
2267
2268 /* check to see if a clock with this name is already registered */
2269 if (clk_core_lookup(core->name)) {
2270 pr_debug("%s: clk %s already initialized\n",
2271 __func__, core->name);
2272 ret = -EEXIST;
2273 goto out;
2274 }
2275
2276 /* check that clk_ops are sane. See Documentation/clk.txt */
2277 if (core->ops->set_rate &&
2278 !((core->ops->round_rate || core->ops->determine_rate) &&
2279 core->ops->recalc_rate)) {
2280 pr_err("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
2281 __func__, core->name);
2282 ret = -EINVAL;
2283 goto out;
2284 }
2285
2286 if (core->ops->set_parent && !core->ops->get_parent) {
2287 pr_err("%s: %s must implement .get_parent & .set_parent\n",
2288 __func__, core->name);
2289 ret = -EINVAL;
2290 goto out;
2291 }
2292
2293 if (core->num_parents > 1 && !core->ops->get_parent) {
2294 pr_err("%s: %s must implement .get_parent as it has multi parents\n",
2295 __func__, core->name);
2296 ret = -EINVAL;
2297 goto out;
2298 }
2299
2300 if (core->ops->set_rate_and_parent &&
2301 !(core->ops->set_parent && core->ops->set_rate)) {
2302 pr_err("%s: %s must implement .set_parent & .set_rate\n",
2303 __func__, core->name);
2304 ret = -EINVAL;
2305 goto out;
2306 }
2307
2308 /* throw a WARN if any entries in parent_names are NULL */
2309 for (i = 0; i < core->num_parents; i++)
2310 WARN(!core->parent_names[i],
2311 "%s: invalid NULL in %s's .parent_names\n",
2312 __func__, core->name);
2313
2314 core->parent = __clk_init_parent(core);
2315
2316 /*
2317 * Populate core->parent if parent has already been clk_core_init'd. If
2318 * parent has not yet been clk_core_init'd then place clk in the orphan
2319 * list. If clk doesn't have any parents then place it in the root
2320 * clk list.
2321 *
2322 * Every time a new clk is clk_init'd then we walk the list of orphan
2323 * clocks and re-parent any that are children of the clock currently
2324 * being clk_init'd.
2325 */
2326 if (core->parent) {
2327 hlist_add_head(&core->child_node,
2328 &core->parent->children);
2329 core->orphan = core->parent->orphan;
2330 } else if (!core->num_parents) {
2331 hlist_add_head(&core->child_node, &clk_root_list);
2332 core->orphan = false;
2333 } else {
2334 hlist_add_head(&core->child_node, &clk_orphan_list);
2335 core->orphan = true;
2336 }
2337
2338 /*
2339 * Set clk's accuracy. The preferred method is to use
2340 * .recalc_accuracy. For simple clocks and lazy developers the default
2341 * fallback is to use the parent's accuracy. If a clock doesn't have a
2342 * parent (or is orphaned) then accuracy is set to zero (perfect
2343 * clock).
2344 */
2345 if (core->ops->recalc_accuracy)
2346 core->accuracy = core->ops->recalc_accuracy(core->hw,
2347 __clk_get_accuracy(core->parent));
2348 else if (core->parent)
2349 core->accuracy = core->parent->accuracy;
2350 else
2351 core->accuracy = 0;
2352
2353 /*
2354 * Set clk's phase.
2355 * Since a phase is by definition relative to its parent, just
2356 * query the current clock phase, or just assume it's in phase.
2357 */
2358 if (core->ops->get_phase)
2359 core->phase = core->ops->get_phase(core->hw);
2360 else
2361 core->phase = 0;
2362
2363 /*
2364 * Set clk's rate. The preferred method is to use .recalc_rate. For
2365 * simple clocks and lazy developers the default fallback is to use the
2366 * parent's rate. If a clock doesn't have a parent (or is orphaned)
2367 * then rate is set to zero.
2368 */
2369 if (core->ops->recalc_rate)
2370 rate = core->ops->recalc_rate(core->hw,
2371 clk_core_get_rate_nolock(core->parent));
2372 else if (core->parent)
2373 rate = core->parent->rate;
2374 else
2375 rate = 0;
2376 core->rate = core->req_rate = rate;
2377
2378 /*
2379 * walk the list of orphan clocks and reparent any that newly finds a
2380 * parent.
2381 */
2382 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
2383 struct clk_core *parent = __clk_init_parent(orphan);
2384
2385 if (parent)
2386 clk_core_reparent(orphan, parent);
2387 }
2388
2389 /*
2390 * optional platform-specific magic
2391 *
2392 * The .init callback is not used by any of the basic clock types, but
2393 * exists for weird hardware that must perform initialization magic.
2394 * Please consider other ways of solving initialization problems before
2395 * using this callback, as its use is discouraged.
2396 */
2397 if (core->ops->init)
2398 core->ops->init(core->hw);
2399
2400 kref_init(&core->ref);
2401out:
2402 clk_prepare_unlock();
2403
2404 if (!ret)
2405 clk_debug_register(core);
2406
2407 return ret;
2408}
2409
2410struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
2411 const char *con_id)
2412{
2413 struct clk *clk;
2414
2415 /* This is to allow this function to be chained to others */
2416 if (IS_ERR_OR_NULL(hw))
2417 return (struct clk *) hw;
2418
2419 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2420 if (!clk)
2421 return ERR_PTR(-ENOMEM);
2422
2423 clk->core = hw->core;
2424 clk->dev_id = dev_id;
2425 clk->con_id = con_id;
2426 clk->max_rate = ULONG_MAX;
2427
2428 clk_prepare_lock();
2429 hlist_add_head(&clk->clks_node, &hw->core->clks);
2430 clk_prepare_unlock();
2431
2432 return clk;
2433}
2434
2435void __clk_free_clk(struct clk *clk)
2436{
2437 clk_prepare_lock();
2438 hlist_del(&clk->clks_node);
2439 clk_prepare_unlock();
2440
2441 kfree(clk);
2442}
2443
2444/**
2445 * clk_register - allocate a new clock, register it and return an opaque cookie
2446 * @dev: device that is registering this clock
2447 * @hw: link to hardware-specific clock data
2448 *
2449 * clk_register is the primary interface for populating the clock tree with new
2450 * clock nodes. It returns a pointer to the newly allocated struct clk which
2451 * cannot be dereferenced by driver code but may be used in conjunction with the
2452 * rest of the clock API. In the event of an error clk_register will return an
2453 * error code; drivers must test for an error code after calling clk_register.
2454 */
2455struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2456{
2457 int i, ret;
2458 struct clk_core *core;
2459
2460 core = kzalloc(sizeof(*core), GFP_KERNEL);
2461 if (!core) {
2462 ret = -ENOMEM;
2463 goto fail_out;
2464 }
2465
2466 core->name = kstrdup_const(hw->init->name, GFP_KERNEL);
2467 if (!core->name) {
2468 ret = -ENOMEM;
2469 goto fail_name;
2470 }
2471 core->ops = hw->init->ops;
2472 if (dev && dev->driver)
2473 core->owner = dev->driver->owner;
2474 core->hw = hw;
2475 core->flags = hw->init->flags;
2476 core->num_parents = hw->init->num_parents;
2477 core->min_rate = 0;
2478 core->max_rate = ULONG_MAX;
2479 hw->core = core;
2480
2481 /* allocate local copy in case parent_names is __initdata */
2482 core->parent_names = kcalloc(core->num_parents, sizeof(char *),
2483 GFP_KERNEL);
2484
2485 if (!core->parent_names) {
2486 ret = -ENOMEM;
2487 goto fail_parent_names;
2488 }
2489
2490
2491 /* copy each string name in case parent_names is __initdata */
2492 for (i = 0; i < core->num_parents; i++) {
2493 core->parent_names[i] = kstrdup_const(hw->init->parent_names[i],
2494 GFP_KERNEL);
2495 if (!core->parent_names[i]) {
2496 ret = -ENOMEM;
2497 goto fail_parent_names_copy;
2498 }
2499 }
2500
2501 /* avoid unnecessary string look-ups of clk_core's possible parents. */
2502 core->parents = kcalloc(core->num_parents, sizeof(*core->parents),
2503 GFP_KERNEL);
2504 if (!core->parents) {
2505 ret = -ENOMEM;
2506 goto fail_parents;
2507 };
2508
2509 INIT_HLIST_HEAD(&core->clks);
2510
2511 hw->clk = __clk_create_clk(hw, NULL, NULL);
2512 if (IS_ERR(hw->clk)) {
2513 ret = PTR_ERR(hw->clk);
2514 goto fail_parents;
2515 }
2516
2517 ret = __clk_core_init(core);
2518 if (!ret)
2519 return hw->clk;
2520
2521 __clk_free_clk(hw->clk);
2522 hw->clk = NULL;
2523
2524fail_parents:
2525 kfree(core->parents);
2526fail_parent_names_copy:
2527 while (--i >= 0)
2528 kfree_const(core->parent_names[i]);
2529 kfree(core->parent_names);
2530fail_parent_names:
2531 kfree_const(core->name);
2532fail_name:
2533 kfree(core);
2534fail_out:
2535 return ERR_PTR(ret);
2536}
2537EXPORT_SYMBOL_GPL(clk_register);
2538
2539/* Free memory allocated for a clock. */
2540static void __clk_release(struct kref *ref)
2541{
2542 struct clk_core *core = container_of(ref, struct clk_core, ref);
2543 int i = core->num_parents;
2544
2545 lockdep_assert_held(&prepare_lock);
2546
2547 kfree(core->parents);
2548 while (--i >= 0)
2549 kfree_const(core->parent_names[i]);
2550
2551 kfree(core->parent_names);
2552 kfree_const(core->name);
2553 kfree(core);
2554}
2555
2556/*
2557 * Empty clk_ops for unregistered clocks. These are used temporarily
2558 * after clk_unregister() was called on a clock and until last clock
2559 * consumer calls clk_put() and the struct clk object is freed.
2560 */
2561static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2562{
2563 return -ENXIO;
2564}
2565
2566static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2567{
2568 WARN_ON_ONCE(1);
2569}
2570
2571static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2572 unsigned long parent_rate)
2573{
2574 return -ENXIO;
2575}
2576
2577static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2578{
2579 return -ENXIO;
2580}
2581
2582static const struct clk_ops clk_nodrv_ops = {
2583 .enable = clk_nodrv_prepare_enable,
2584 .disable = clk_nodrv_disable_unprepare,
2585 .prepare = clk_nodrv_prepare_enable,
2586 .unprepare = clk_nodrv_disable_unprepare,
2587 .set_rate = clk_nodrv_set_rate,
2588 .set_parent = clk_nodrv_set_parent,
2589};
2590
2591/**
2592 * clk_unregister - unregister a currently registered clock
2593 * @clk: clock to unregister
2594 */
2595void clk_unregister(struct clk *clk)
2596{
2597 unsigned long flags;
2598
2599 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2600 return;
2601
2602 clk_debug_unregister(clk->core);
2603
2604 clk_prepare_lock();
2605
2606 if (clk->core->ops == &clk_nodrv_ops) {
2607 pr_err("%s: unregistered clock: %s\n", __func__,
2608 clk->core->name);
2609 goto unlock;
2610 }
2611 /*
2612 * Assign empty clock ops for consumers that might still hold
2613 * a reference to this clock.
2614 */
2615 flags = clk_enable_lock();
2616 clk->core->ops = &clk_nodrv_ops;
2617 clk_enable_unlock(flags);
2618
2619 if (!hlist_empty(&clk->core->children)) {
2620 struct clk_core *child;
2621 struct hlist_node *t;
2622
2623 /* Reparent all children to the orphan list. */
2624 hlist_for_each_entry_safe(child, t, &clk->core->children,
2625 child_node)
2626 clk_core_set_parent(child, NULL);
2627 }
2628
2629 hlist_del_init(&clk->core->child_node);
2630
2631 if (clk->core->prepare_count)
2632 pr_warn("%s: unregistering prepared clock: %s\n",
2633 __func__, clk->core->name);
2634 kref_put(&clk->core->ref, __clk_release);
2635unlock:
2636 clk_prepare_unlock();
2637}
2638EXPORT_SYMBOL_GPL(clk_unregister);
2639
2640static void devm_clk_release(struct device *dev, void *res)
2641{
2642 clk_unregister(*(struct clk **)res);
2643}
2644
2645/**
2646 * devm_clk_register - resource managed clk_register()
2647 * @dev: device that is registering this clock
2648 * @hw: link to hardware-specific clock data
2649 *
2650 * Managed clk_register(). Clocks returned from this function are
2651 * automatically clk_unregister()ed on driver detach. See clk_register() for
2652 * more information.
2653 */
2654struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2655{
2656 struct clk *clk;
2657 struct clk **clkp;
2658
2659 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2660 if (!clkp)
2661 return ERR_PTR(-ENOMEM);
2662
2663 clk = clk_register(dev, hw);
2664 if (!IS_ERR(clk)) {
2665 *clkp = clk;
2666 devres_add(dev, clkp);
2667 } else {
2668 devres_free(clkp);
2669 }
2670
2671 return clk;
2672}
2673EXPORT_SYMBOL_GPL(devm_clk_register);
2674
2675static int devm_clk_match(struct device *dev, void *res, void *data)
2676{
2677 struct clk *c = res;
2678 if (WARN_ON(!c))
2679 return 0;
2680 return c == data;
2681}
2682
2683/**
2684 * devm_clk_unregister - resource managed clk_unregister()
2685 * @clk: clock to unregister
2686 *
2687 * Deallocate a clock allocated with devm_clk_register(). Normally
2688 * this function will not need to be called and the resource management
2689 * code will ensure that the resource is freed.
2690 */
2691void devm_clk_unregister(struct device *dev, struct clk *clk)
2692{
2693 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2694}
2695EXPORT_SYMBOL_GPL(devm_clk_unregister);
2696
2697/*
2698 * clkdev helpers
2699 */
2700int __clk_get(struct clk *clk)
2701{
2702 struct clk_core *core = !clk ? NULL : clk->core;
2703
2704 if (core) {
2705 if (!try_module_get(core->owner))
2706 return 0;
2707
2708 kref_get(&core->ref);
2709 }
2710 return 1;
2711}
2712
2713void __clk_put(struct clk *clk)
2714{
2715 struct module *owner;
2716
2717 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2718 return;
2719
2720 clk_prepare_lock();
2721
2722 hlist_del(&clk->clks_node);
2723 if (clk->min_rate > clk->core->req_rate ||
2724 clk->max_rate < clk->core->req_rate)
2725 clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
2726
2727 owner = clk->core->owner;
2728 kref_put(&clk->core->ref, __clk_release);
2729
2730 clk_prepare_unlock();
2731
2732 module_put(owner);
2733
2734 kfree(clk);
2735}
2736
2737/*** clk rate change notifiers ***/
2738
2739/**
2740 * clk_notifier_register - add a clk rate change notifier
2741 * @clk: struct clk * to watch
2742 * @nb: struct notifier_block * with callback info
2743 *
2744 * Request notification when clk's rate changes. This uses an SRCU
2745 * notifier because we want it to block and notifier unregistrations are
2746 * uncommon. The callbacks associated with the notifier must not
2747 * re-enter into the clk framework by calling any top-level clk APIs;
2748 * this will cause a nested prepare_lock mutex.
2749 *
2750 * In all notification cases (pre, post and abort rate change) the original
2751 * clock rate is passed to the callback via struct clk_notifier_data.old_rate
2752 * and the new frequency is passed via struct clk_notifier_data.new_rate.
2753 *
2754 * clk_notifier_register() must be called from non-atomic context.
2755 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2756 * allocation failure; otherwise, passes along the return value of
2757 * srcu_notifier_chain_register().
2758 */
2759int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2760{
2761 struct clk_notifier *cn;
2762 int ret = -ENOMEM;
2763
2764 if (!clk || !nb)
2765 return -EINVAL;
2766
2767 clk_prepare_lock();
2768
2769 /* search the list of notifiers for this clk */
2770 list_for_each_entry(cn, &clk_notifier_list, node)
2771 if (cn->clk == clk)
2772 break;
2773
2774 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2775 if (cn->clk != clk) {
2776 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2777 if (!cn)
2778 goto out;
2779
2780 cn->clk = clk;
2781 srcu_init_notifier_head(&cn->notifier_head);
2782
2783 list_add(&cn->node, &clk_notifier_list);
2784 }
2785
2786 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2787
2788 clk->core->notifier_count++;
2789
2790out:
2791 clk_prepare_unlock();
2792
2793 return ret;
2794}
2795EXPORT_SYMBOL_GPL(clk_notifier_register);
2796
2797/**
2798 * clk_notifier_unregister - remove a clk rate change notifier
2799 * @clk: struct clk *
2800 * @nb: struct notifier_block * with callback info
2801 *
2802 * Request no further notification for changes to 'clk' and frees memory
2803 * allocated in clk_notifier_register.
2804 *
2805 * Returns -EINVAL if called with null arguments; otherwise, passes
2806 * along the return value of srcu_notifier_chain_unregister().
2807 */
2808int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2809{
2810 struct clk_notifier *cn = NULL;
2811 int ret = -EINVAL;
2812
2813 if (!clk || !nb)
2814 return -EINVAL;
2815
2816 clk_prepare_lock();
2817
2818 list_for_each_entry(cn, &clk_notifier_list, node)
2819 if (cn->clk == clk)
2820 break;
2821
2822 if (cn->clk == clk) {
2823 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2824
2825 clk->core->notifier_count--;
2826
2827 /* XXX the notifier code should handle this better */
2828 if (!cn->notifier_head.head) {
2829 srcu_cleanup_notifier_head(&cn->notifier_head);
2830 list_del(&cn->node);
2831 kfree(cn);
2832 }
2833
2834 } else {
2835 ret = -ENOENT;
2836 }
2837
2838 clk_prepare_unlock();
2839
2840 return ret;
2841}
2842EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2843
2844#ifdef CONFIG_OF
2845/**
2846 * struct of_clk_provider - Clock provider registration structure
2847 * @link: Entry in global list of clock providers
2848 * @node: Pointer to device tree node of clock provider
2849 * @get: Get clock callback. Returns NULL or a struct clk for the
2850 * given clock specifier
2851 * @data: context pointer to be passed into @get callback
2852 */
2853struct of_clk_provider {
2854 struct list_head link;
2855
2856 struct device_node *node;
2857 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2858 void *data;
2859};
2860
2861static const struct of_device_id __clk_of_table_sentinel
2862 __used __section(__clk_of_table_end);
2863
2864static LIST_HEAD(of_clk_providers);
2865static DEFINE_MUTEX(of_clk_mutex);
2866
2867struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2868 void *data)
2869{
2870 return data;
2871}
2872EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2873
2874struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2875{
2876 struct clk_onecell_data *clk_data = data;
2877 unsigned int idx = clkspec->args[0];
2878
2879 if (idx >= clk_data->clk_num) {
2880 pr_err("%s: invalid clock index %u\n", __func__, idx);
2881 return ERR_PTR(-EINVAL);
2882 }
2883
2884 return clk_data->clks[idx];
2885}
2886EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2887
2888/**
2889 * of_clk_add_provider() - Register a clock provider for a node
2890 * @np: Device node pointer associated with clock provider
2891 * @clk_src_get: callback for decoding clock
2892 * @data: context pointer for @clk_src_get callback.
2893 */
2894int of_clk_add_provider(struct device_node *np,
2895 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2896 void *data),
2897 void *data)
2898{
2899 struct of_clk_provider *cp;
2900 int ret;
2901
2902 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2903 if (!cp)
2904 return -ENOMEM;
2905
2906 cp->node = of_node_get(np);
2907 cp->data = data;
2908 cp->get = clk_src_get;
2909
2910 mutex_lock(&of_clk_mutex);
2911 list_add(&cp->link, &of_clk_providers);
2912 mutex_unlock(&of_clk_mutex);
2913 pr_debug("Added clock from %s\n", np->full_name);
2914
2915 ret = of_clk_set_defaults(np, true);
2916 if (ret < 0)
2917 of_clk_del_provider(np);
2918
2919 return ret;
2920}
2921EXPORT_SYMBOL_GPL(of_clk_add_provider);
2922
2923/**
2924 * of_clk_del_provider() - Remove a previously registered clock provider
2925 * @np: Device node pointer associated with clock provider
2926 */
2927void of_clk_del_provider(struct device_node *np)
2928{
2929 struct of_clk_provider *cp;
2930
2931 mutex_lock(&of_clk_mutex);
2932 list_for_each_entry(cp, &of_clk_providers, link) {
2933 if (cp->node == np) {
2934 list_del(&cp->link);
2935 of_node_put(cp->node);
2936 kfree(cp);
2937 break;
2938 }
2939 }
2940 mutex_unlock(&of_clk_mutex);
2941}
2942EXPORT_SYMBOL_GPL(of_clk_del_provider);
2943
2944struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
2945 const char *dev_id, const char *con_id)
2946{
2947 struct of_clk_provider *provider;
2948 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2949
2950 if (!clkspec)
2951 return ERR_PTR(-EINVAL);
2952
2953 /* Check if we have such a provider in our array */
2954 mutex_lock(&of_clk_mutex);
2955 list_for_each_entry(provider, &of_clk_providers, link) {
2956 if (provider->node == clkspec->np)
2957 clk = provider->get(clkspec, provider->data);
2958 if (!IS_ERR(clk)) {
2959 clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
2960 con_id);
2961
2962 if (!IS_ERR(clk) && !__clk_get(clk)) {
2963 __clk_free_clk(clk);
2964 clk = ERR_PTR(-ENOENT);
2965 }
2966
2967 break;
2968 }
2969 }
2970 mutex_unlock(&of_clk_mutex);
2971
2972 return clk;
2973}
2974
2975/**
2976 * of_clk_get_from_provider() - Lookup a clock from a clock provider
2977 * @clkspec: pointer to a clock specifier data structure
2978 *
2979 * This function looks up a struct clk from the registered list of clock
2980 * providers, an input is a clock specifier data structure as returned
2981 * from the of_parse_phandle_with_args() function call.
2982 */
2983struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2984{
2985 return __of_clk_get_from_provider(clkspec, NULL, __func__);
2986}
2987EXPORT_SYMBOL_GPL(of_clk_get_from_provider);
2988
2989/**
2990 * of_clk_get_parent_count() - Count the number of clocks a device node has
2991 * @np: device node to count
2992 *
2993 * Returns: The number of clocks that are possible parents of this node
2994 */
2995unsigned int of_clk_get_parent_count(struct device_node *np)
2996{
2997 int count;
2998
2999 count = of_count_phandle_with_args(np, "clocks", "#clock-cells");
3000 if (count < 0)
3001 return 0;
3002
3003 return count;
3004}
3005EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
3006
3007const char *of_clk_get_parent_name(struct device_node *np, int index)
3008{
3009 struct of_phandle_args clkspec;
3010 struct property *prop;
3011 const char *clk_name;
3012 const __be32 *vp;
3013 u32 pv;
3014 int rc;
3015 int count;
3016 struct clk *clk;
3017
3018 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
3019 &clkspec);
3020 if (rc)
3021 return NULL;
3022
3023 index = clkspec.args_count ? clkspec.args[0] : 0;
3024 count = 0;
3025
3026 /* if there is an indices property, use it to transfer the index
3027 * specified into an array offset for the clock-output-names property.
3028 */
3029 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
3030 if (index == pv) {
3031 index = count;
3032 break;
3033 }
3034 count++;
3035 }
3036 /* We went off the end of 'clock-indices' without finding it */
3037 if (prop && !vp)
3038 return NULL;
3039
3040 if (of_property_read_string_index(clkspec.np, "clock-output-names",
3041 index,
3042 &clk_name) < 0) {
3043 /*
3044 * Best effort to get the name if the clock has been
3045 * registered with the framework. If the clock isn't
3046 * registered, we return the node name as the name of
3047 * the clock as long as #clock-cells = 0.
3048 */
3049 clk = of_clk_get_from_provider(&clkspec);
3050 if (IS_ERR(clk)) {
3051 if (clkspec.args_count == 0)
3052 clk_name = clkspec.np->name;
3053 else
3054 clk_name = NULL;
3055 } else {
3056 clk_name = __clk_get_name(clk);
3057 clk_put(clk);
3058 }
3059 }
3060
3061
3062 of_node_put(clkspec.np);
3063 return clk_name;
3064}
3065EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
3066
3067/**
3068 * of_clk_parent_fill() - Fill @parents with names of @np's parents and return
3069 * number of parents
3070 * @np: Device node pointer associated with clock provider
3071 * @parents: pointer to char array that hold the parents' names
3072 * @size: size of the @parents array
3073 *
3074 * Return: number of parents for the clock node.
3075 */
3076int of_clk_parent_fill(struct device_node *np, const char **parents,
3077 unsigned int size)
3078{
3079 unsigned int i = 0;
3080
3081 while (i < size && (parents[i] = of_clk_get_parent_name(np, i)) != NULL)
3082 i++;
3083
3084 return i;
3085}
3086EXPORT_SYMBOL_GPL(of_clk_parent_fill);
3087
3088struct clock_provider {
3089 of_clk_init_cb_t clk_init_cb;
3090 struct device_node *np;
3091 struct list_head node;
3092};
3093
3094/*
3095 * This function looks for a parent clock. If there is one, then it
3096 * checks that the provider for this parent clock was initialized, in
3097 * this case the parent clock will be ready.
3098 */
3099static int parent_ready(struct device_node *np)
3100{
3101 int i = 0;
3102
3103 while (true) {
3104 struct clk *clk = of_clk_get(np, i);
3105
3106 /* this parent is ready we can check the next one */
3107 if (!IS_ERR(clk)) {
3108 clk_put(clk);
3109 i++;
3110 continue;
3111 }
3112
3113 /* at least one parent is not ready, we exit now */
3114 if (PTR_ERR(clk) == -EPROBE_DEFER)
3115 return 0;
3116
3117 /*
3118 * Here we make assumption that the device tree is
3119 * written correctly. So an error means that there is
3120 * no more parent. As we didn't exit yet, then the
3121 * previous parent are ready. If there is no clock
3122 * parent, no need to wait for them, then we can
3123 * consider their absence as being ready
3124 */
3125 return 1;
3126 }
3127}
3128
3129/**
3130 * of_clk_init() - Scan and init clock providers from the DT
3131 * @matches: array of compatible values and init functions for providers.
3132 *
3133 * This function scans the device tree for matching clock providers
3134 * and calls their initialization functions. It also does it by trying
3135 * to follow the dependencies.
3136 */
3137void __init of_clk_init(const struct of_device_id *matches)
3138{
3139 const struct of_device_id *match;
3140 struct device_node *np;
3141 struct clock_provider *clk_provider, *next;
3142 bool is_init_done;
3143 bool force = false;
3144 LIST_HEAD(clk_provider_list);
3145
3146 if (!matches)
3147 matches = &__clk_of_table;
3148
3149 /* First prepare the list of the clocks providers */
3150 for_each_matching_node_and_match(np, matches, &match) {
3151 struct clock_provider *parent;
3152
3153 if (!of_device_is_available(np))
3154 continue;
3155
3156 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
3157 if (!parent) {
3158 list_for_each_entry_safe(clk_provider, next,
3159 &clk_provider_list, node) {
3160 list_del(&clk_provider->node);
3161 of_node_put(clk_provider->np);
3162 kfree(clk_provider);
3163 }
3164 of_node_put(np);
3165 return;
3166 }
3167
3168 parent->clk_init_cb = match->data;
3169 parent->np = of_node_get(np);
3170 list_add_tail(&parent->node, &clk_provider_list);
3171 }
3172
3173 while (!list_empty(&clk_provider_list)) {
3174 is_init_done = false;
3175 list_for_each_entry_safe(clk_provider, next,
3176 &clk_provider_list, node) {
3177 if (force || parent_ready(clk_provider->np)) {
3178
3179 clk_provider->clk_init_cb(clk_provider->np);
3180 of_clk_set_defaults(clk_provider->np, true);
3181
3182 list_del(&clk_provider->node);
3183 of_node_put(clk_provider->np);
3184 kfree(clk_provider);
3185 is_init_done = true;
3186 }
3187 }
3188
3189 /*
3190 * We didn't manage to initialize any of the
3191 * remaining providers during the last loop, so now we
3192 * initialize all the remaining ones unconditionally
3193 * in case the clock parent was not mandatory
3194 */
3195 if (!is_init_done)
3196 force = true;
3197 }
3198}
3199#endif