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