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b2476490 MT |
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 | ||
20 | static DEFINE_SPINLOCK(enable_lock); | |
21 | static DEFINE_MUTEX(prepare_lock); | |
22 | ||
23 | static HLIST_HEAD(clk_root_list); | |
24 | static HLIST_HEAD(clk_orphan_list); | |
25 | static LIST_HEAD(clk_notifier_list); | |
26 | ||
27 | /*** debugfs support ***/ | |
28 | ||
29 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
30 | #include <linux/debugfs.h> | |
31 | ||
32 | static struct dentry *rootdir; | |
33 | static struct dentry *orphandir; | |
34 | static int inited = 0; | |
35 | ||
36 | /* caller must hold prepare_lock */ | |
37 | static 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 | ||
81 | err_out: | |
82 | debugfs_remove(clk->dentry); | |
83 | out: | |
84 | return ret; | |
85 | } | |
86 | ||
87 | /* caller must hold prepare_lock */ | |
88 | static 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; | |
106 | out: | |
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 | */ | |
121 | static 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 | ||
149 | out: | |
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 | */ | |
165 | static 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 | } | |
194 | late_initcall(clk_debug_init); | |
195 | #else | |
196 | static inline int clk_debug_register(struct clk *clk) { return 0; } | |
197 | #endif /* CONFIG_COMMON_CLK_DEBUG */ | |
198 | ||
199 | #ifdef CONFIG_COMMON_CLK_DISABLE_UNUSED | |
200 | /* caller must hold prepare_lock */ | |
201 | static void clk_disable_unused_subtree(struct clk *clk) | |
202 | { | |
203 | struct clk *child; | |
204 | struct hlist_node *tmp; | |
205 | unsigned long flags; | |
206 | ||
207 | if (!clk) | |
208 | goto out; | |
209 | ||
210 | hlist_for_each_entry(child, tmp, &clk->children, child_node) | |
211 | clk_disable_unused_subtree(child); | |
212 | ||
213 | spin_lock_irqsave(&enable_lock, flags); | |
214 | ||
215 | if (clk->enable_count) | |
216 | goto unlock_out; | |
217 | ||
218 | if (clk->flags & CLK_IGNORE_UNUSED) | |
219 | goto unlock_out; | |
220 | ||
221 | if (__clk_is_enabled(clk) && clk->ops->disable) | |
222 | clk->ops->disable(clk->hw); | |
223 | ||
224 | unlock_out: | |
225 | spin_unlock_irqrestore(&enable_lock, flags); | |
226 | ||
227 | out: | |
228 | return; | |
229 | } | |
230 | ||
231 | static int clk_disable_unused(void) | |
232 | { | |
233 | struct clk *clk; | |
234 | struct hlist_node *tmp; | |
235 | ||
236 | mutex_lock(&prepare_lock); | |
237 | ||
238 | hlist_for_each_entry(clk, tmp, &clk_root_list, child_node) | |
239 | clk_disable_unused_subtree(clk); | |
240 | ||
241 | hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node) | |
242 | clk_disable_unused_subtree(clk); | |
243 | ||
244 | mutex_unlock(&prepare_lock); | |
245 | ||
246 | return 0; | |
247 | } | |
248 | late_initcall(clk_disable_unused); | |
249 | #else | |
250 | static inline int clk_disable_unused(struct clk *clk) { return 0; } | |
251 | #endif /* CONFIG_COMMON_CLK_DISABLE_UNUSED */ | |
252 | ||
253 | /*** helper functions ***/ | |
254 | ||
255 | inline const char *__clk_get_name(struct clk *clk) | |
256 | { | |
257 | return !clk ? NULL : clk->name; | |
258 | } | |
259 | ||
260 | inline struct clk_hw *__clk_get_hw(struct clk *clk) | |
261 | { | |
262 | return !clk ? NULL : clk->hw; | |
263 | } | |
264 | ||
265 | inline u8 __clk_get_num_parents(struct clk *clk) | |
266 | { | |
267 | return !clk ? -EINVAL : clk->num_parents; | |
268 | } | |
269 | ||
270 | inline struct clk *__clk_get_parent(struct clk *clk) | |
271 | { | |
272 | return !clk ? NULL : clk->parent; | |
273 | } | |
274 | ||
275 | inline int __clk_get_enable_count(struct clk *clk) | |
276 | { | |
277 | return !clk ? -EINVAL : clk->enable_count; | |
278 | } | |
279 | ||
280 | inline int __clk_get_prepare_count(struct clk *clk) | |
281 | { | |
282 | return !clk ? -EINVAL : clk->prepare_count; | |
283 | } | |
284 | ||
285 | unsigned long __clk_get_rate(struct clk *clk) | |
286 | { | |
287 | unsigned long ret; | |
288 | ||
289 | if (!clk) { | |
290 | ret = -EINVAL; | |
291 | goto out; | |
292 | } | |
293 | ||
294 | ret = clk->rate; | |
295 | ||
296 | if (clk->flags & CLK_IS_ROOT) | |
297 | goto out; | |
298 | ||
299 | if (!clk->parent) | |
300 | ret = -ENODEV; | |
301 | ||
302 | out: | |
303 | return ret; | |
304 | } | |
305 | ||
306 | inline unsigned long __clk_get_flags(struct clk *clk) | |
307 | { | |
308 | return !clk ? -EINVAL : clk->flags; | |
309 | } | |
310 | ||
311 | int __clk_is_enabled(struct clk *clk) | |
312 | { | |
313 | int ret; | |
314 | ||
315 | if (!clk) | |
316 | return -EINVAL; | |
317 | ||
318 | /* | |
319 | * .is_enabled is only mandatory for clocks that gate | |
320 | * fall back to software usage counter if .is_enabled is missing | |
321 | */ | |
322 | if (!clk->ops->is_enabled) { | |
323 | ret = clk->enable_count ? 1 : 0; | |
324 | goto out; | |
325 | } | |
326 | ||
327 | ret = clk->ops->is_enabled(clk->hw); | |
328 | out: | |
329 | return ret; | |
330 | } | |
331 | ||
332 | static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk) | |
333 | { | |
334 | struct clk *child; | |
335 | struct clk *ret; | |
336 | struct hlist_node *tmp; | |
337 | ||
338 | if (!strcmp(clk->name, name)) | |
339 | return clk; | |
340 | ||
341 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
342 | ret = __clk_lookup_subtree(name, child); | |
343 | if (ret) | |
344 | return ret; | |
345 | } | |
346 | ||
347 | return NULL; | |
348 | } | |
349 | ||
350 | struct clk *__clk_lookup(const char *name) | |
351 | { | |
352 | struct clk *root_clk; | |
353 | struct clk *ret; | |
354 | struct hlist_node *tmp; | |
355 | ||
356 | if (!name) | |
357 | return NULL; | |
358 | ||
359 | /* search the 'proper' clk tree first */ | |
360 | hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) { | |
361 | ret = __clk_lookup_subtree(name, root_clk); | |
362 | if (ret) | |
363 | return ret; | |
364 | } | |
365 | ||
366 | /* if not found, then search the orphan tree */ | |
367 | hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) { | |
368 | ret = __clk_lookup_subtree(name, root_clk); | |
369 | if (ret) | |
370 | return ret; | |
371 | } | |
372 | ||
373 | return NULL; | |
374 | } | |
375 | ||
376 | /*** clk api ***/ | |
377 | ||
378 | void __clk_unprepare(struct clk *clk) | |
379 | { | |
380 | if (!clk) | |
381 | return; | |
382 | ||
383 | if (WARN_ON(clk->prepare_count == 0)) | |
384 | return; | |
385 | ||
386 | if (--clk->prepare_count > 0) | |
387 | return; | |
388 | ||
389 | WARN_ON(clk->enable_count > 0); | |
390 | ||
391 | if (clk->ops->unprepare) | |
392 | clk->ops->unprepare(clk->hw); | |
393 | ||
394 | __clk_unprepare(clk->parent); | |
395 | } | |
396 | ||
397 | /** | |
398 | * clk_unprepare - undo preparation of a clock source | |
399 | * @clk: the clk being unprepare | |
400 | * | |
401 | * clk_unprepare may sleep, which differentiates it from clk_disable. In a | |
402 | * simple case, clk_unprepare can be used instead of clk_disable to gate a clk | |
403 | * if the operation may sleep. One example is a clk which is accessed over | |
404 | * I2c. In the complex case a clk gate operation may require a fast and a slow | |
405 | * part. It is this reason that clk_unprepare and clk_disable are not mutually | |
406 | * exclusive. In fact clk_disable must be called before clk_unprepare. | |
407 | */ | |
408 | void clk_unprepare(struct clk *clk) | |
409 | { | |
410 | mutex_lock(&prepare_lock); | |
411 | __clk_unprepare(clk); | |
412 | mutex_unlock(&prepare_lock); | |
413 | } | |
414 | EXPORT_SYMBOL_GPL(clk_unprepare); | |
415 | ||
416 | int __clk_prepare(struct clk *clk) | |
417 | { | |
418 | int ret = 0; | |
419 | ||
420 | if (!clk) | |
421 | return 0; | |
422 | ||
423 | if (clk->prepare_count == 0) { | |
424 | ret = __clk_prepare(clk->parent); | |
425 | if (ret) | |
426 | return ret; | |
427 | ||
428 | if (clk->ops->prepare) { | |
429 | ret = clk->ops->prepare(clk->hw); | |
430 | if (ret) { | |
431 | __clk_unprepare(clk->parent); | |
432 | return ret; | |
433 | } | |
434 | } | |
435 | } | |
436 | ||
437 | clk->prepare_count++; | |
438 | ||
439 | return 0; | |
440 | } | |
441 | ||
442 | /** | |
443 | * clk_prepare - prepare a clock source | |
444 | * @clk: the clk being prepared | |
445 | * | |
446 | * clk_prepare may sleep, which differentiates it from clk_enable. In a simple | |
447 | * case, clk_prepare can be used instead of clk_enable to ungate a clk if the | |
448 | * operation may sleep. One example is a clk which is accessed over I2c. In | |
449 | * the complex case a clk ungate operation may require a fast and a slow part. | |
450 | * It is this reason that clk_prepare and clk_enable are not mutually | |
451 | * exclusive. In fact clk_prepare must be called before clk_enable. | |
452 | * Returns 0 on success, -EERROR otherwise. | |
453 | */ | |
454 | int clk_prepare(struct clk *clk) | |
455 | { | |
456 | int ret; | |
457 | ||
458 | mutex_lock(&prepare_lock); | |
459 | ret = __clk_prepare(clk); | |
460 | mutex_unlock(&prepare_lock); | |
461 | ||
462 | return ret; | |
463 | } | |
464 | EXPORT_SYMBOL_GPL(clk_prepare); | |
465 | ||
466 | static void __clk_disable(struct clk *clk) | |
467 | { | |
468 | if (!clk) | |
469 | return; | |
470 | ||
471 | if (WARN_ON(clk->enable_count == 0)) | |
472 | return; | |
473 | ||
474 | if (--clk->enable_count > 0) | |
475 | return; | |
476 | ||
477 | if (clk->ops->disable) | |
478 | clk->ops->disable(clk->hw); | |
479 | ||
480 | __clk_disable(clk->parent); | |
481 | } | |
482 | ||
483 | /** | |
484 | * clk_disable - gate a clock | |
485 | * @clk: the clk being gated | |
486 | * | |
487 | * clk_disable must not sleep, which differentiates it from clk_unprepare. In | |
488 | * a simple case, clk_disable can be used instead of clk_unprepare to gate a | |
489 | * clk if the operation is fast and will never sleep. One example is a | |
490 | * SoC-internal clk which is controlled via simple register writes. In the | |
491 | * complex case a clk gate operation may require a fast and a slow part. It is | |
492 | * this reason that clk_unprepare and clk_disable are not mutually exclusive. | |
493 | * In fact clk_disable must be called before clk_unprepare. | |
494 | */ | |
495 | void clk_disable(struct clk *clk) | |
496 | { | |
497 | unsigned long flags; | |
498 | ||
499 | spin_lock_irqsave(&enable_lock, flags); | |
500 | __clk_disable(clk); | |
501 | spin_unlock_irqrestore(&enable_lock, flags); | |
502 | } | |
503 | EXPORT_SYMBOL_GPL(clk_disable); | |
504 | ||
505 | static int __clk_enable(struct clk *clk) | |
506 | { | |
507 | int ret = 0; | |
508 | ||
509 | if (!clk) | |
510 | return 0; | |
511 | ||
512 | if (WARN_ON(clk->prepare_count == 0)) | |
513 | return -ESHUTDOWN; | |
514 | ||
515 | if (clk->enable_count == 0) { | |
516 | ret = __clk_enable(clk->parent); | |
517 | ||
518 | if (ret) | |
519 | return ret; | |
520 | ||
521 | if (clk->ops->enable) { | |
522 | ret = clk->ops->enable(clk->hw); | |
523 | if (ret) { | |
524 | __clk_disable(clk->parent); | |
525 | return ret; | |
526 | } | |
527 | } | |
528 | } | |
529 | ||
530 | clk->enable_count++; | |
531 | return 0; | |
532 | } | |
533 | ||
534 | /** | |
535 | * clk_enable - ungate a clock | |
536 | * @clk: the clk being ungated | |
537 | * | |
538 | * clk_enable must not sleep, which differentiates it from clk_prepare. In a | |
539 | * simple case, clk_enable can be used instead of clk_prepare to ungate a clk | |
540 | * if the operation will never sleep. One example is a SoC-internal clk which | |
541 | * is controlled via simple register writes. In the complex case a clk ungate | |
542 | * operation may require a fast and a slow part. It is this reason that | |
543 | * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare | |
544 | * must be called before clk_enable. Returns 0 on success, -EERROR | |
545 | * otherwise. | |
546 | */ | |
547 | int clk_enable(struct clk *clk) | |
548 | { | |
549 | unsigned long flags; | |
550 | int ret; | |
551 | ||
552 | spin_lock_irqsave(&enable_lock, flags); | |
553 | ret = __clk_enable(clk); | |
554 | spin_unlock_irqrestore(&enable_lock, flags); | |
555 | ||
556 | return ret; | |
557 | } | |
558 | EXPORT_SYMBOL_GPL(clk_enable); | |
559 | ||
560 | /** | |
561 | * clk_get_rate - return the rate of clk | |
562 | * @clk: the clk whose rate is being returned | |
563 | * | |
564 | * Simply returns the cached rate of the clk. Does not query the hardware. If | |
565 | * clk is NULL then returns -EINVAL. | |
566 | */ | |
567 | unsigned long clk_get_rate(struct clk *clk) | |
568 | { | |
569 | unsigned long rate; | |
570 | ||
571 | mutex_lock(&prepare_lock); | |
572 | rate = __clk_get_rate(clk); | |
573 | mutex_unlock(&prepare_lock); | |
574 | ||
575 | return rate; | |
576 | } | |
577 | EXPORT_SYMBOL_GPL(clk_get_rate); | |
578 | ||
579 | /** | |
580 | * __clk_round_rate - round the given rate for a clk | |
581 | * @clk: round the rate of this clock | |
582 | * | |
583 | * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate | |
584 | */ | |
585 | unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) | |
586 | { | |
587 | unsigned long unused; | |
588 | ||
589 | if (!clk) | |
590 | return -EINVAL; | |
591 | ||
592 | if (!clk->ops->round_rate) | |
593 | return clk->rate; | |
594 | ||
595 | if (clk->flags & CLK_SET_RATE_PARENT) | |
596 | return clk->ops->round_rate(clk->hw, rate, &unused); | |
597 | else | |
598 | return clk->ops->round_rate(clk->hw, rate, NULL); | |
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 | */ | |
610 | long 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 | } | |
620 | EXPORT_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 | */ | |
636 | static 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 | */ | |
672 | static 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 | */ | |
716 | static 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 | ||
741 | out: | |
742 | return ret; | |
743 | } | |
744 | ||
745 | static 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 | */ | |
765 | static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) | |
766 | { | |
767 | struct clk *top = clk; | |
768 | unsigned long best_parent_rate = clk->parent->rate; | |
769 | unsigned long new_rate; | |
770 | ||
771 | if (!clk->ops->round_rate && !(clk->flags & CLK_SET_RATE_PARENT)) { | |
772 | clk->new_rate = clk->rate; | |
773 | return NULL; | |
774 | } | |
775 | ||
776 | if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) { | |
777 | top = clk_calc_new_rates(clk->parent, rate); | |
778 | new_rate = clk->new_rate = clk->parent->new_rate; | |
779 | ||
780 | goto out; | |
781 | } | |
782 | ||
783 | if (clk->flags & CLK_SET_RATE_PARENT) | |
784 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); | |
785 | else | |
786 | new_rate = clk->ops->round_rate(clk->hw, rate, NULL); | |
787 | ||
788 | if (best_parent_rate != clk->parent->rate) { | |
789 | top = clk_calc_new_rates(clk->parent, best_parent_rate); | |
790 | ||
791 | goto out; | |
792 | } | |
793 | ||
794 | out: | |
795 | clk_calc_subtree(clk, new_rate); | |
796 | ||
797 | return top; | |
798 | } | |
799 | ||
800 | /* | |
801 | * Notify about rate changes in a subtree. Always walk down the whole tree | |
802 | * so that in case of an error we can walk down the whole tree again and | |
803 | * abort the change. | |
804 | */ | |
805 | static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) | |
806 | { | |
807 | struct hlist_node *tmp; | |
808 | struct clk *child, *fail_clk = NULL; | |
809 | int ret = NOTIFY_DONE; | |
810 | ||
811 | if (clk->rate == clk->new_rate) | |
812 | return 0; | |
813 | ||
814 | if (clk->notifier_count) { | |
815 | ret = __clk_notify(clk, event, clk->rate, clk->new_rate); | |
816 | if (ret == NOTIFY_BAD) | |
817 | fail_clk = clk; | |
818 | } | |
819 | ||
820 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
821 | clk = clk_propagate_rate_change(child, event); | |
822 | if (clk) | |
823 | fail_clk = clk; | |
824 | } | |
825 | ||
826 | return fail_clk; | |
827 | } | |
828 | ||
829 | /* | |
830 | * walk down a subtree and set the new rates notifying the rate | |
831 | * change on the way | |
832 | */ | |
833 | static void clk_change_rate(struct clk *clk) | |
834 | { | |
835 | struct clk *child; | |
836 | unsigned long old_rate; | |
837 | struct hlist_node *tmp; | |
838 | ||
839 | old_rate = clk->rate; | |
840 | ||
841 | if (clk->ops->set_rate) | |
842 | clk->ops->set_rate(clk->hw, clk->new_rate); | |
843 | ||
844 | if (clk->ops->recalc_rate) | |
845 | clk->rate = clk->ops->recalc_rate(clk->hw, | |
846 | clk->parent->rate); | |
847 | else | |
848 | clk->rate = clk->parent->rate; | |
849 | ||
850 | if (clk->notifier_count && old_rate != clk->rate) | |
851 | __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); | |
852 | ||
853 | hlist_for_each_entry(child, tmp, &clk->children, child_node) | |
854 | clk_change_rate(child); | |
855 | } | |
856 | ||
857 | /** | |
858 | * clk_set_rate - specify a new rate for clk | |
859 | * @clk: the clk whose rate is being changed | |
860 | * @rate: the new rate for clk | |
861 | * | |
862 | * In the simplest case clk_set_rate will only change the rate of clk. | |
863 | * | |
864 | * If clk has the CLK_SET_RATE_GATE flag set and it is enabled this call | |
865 | * will fail; only when the clk is disabled will it be able to change | |
866 | * its rate. | |
867 | * | |
868 | * Setting the CLK_SET_RATE_PARENT flag allows clk_set_rate to | |
869 | * recursively propagate up to clk's parent; whether or not this happens | |
870 | * depends on the outcome of clk's .round_rate implementation. If | |
871 | * *parent_rate is 0 after calling .round_rate then upstream parent | |
872 | * propagation is ignored. If *parent_rate comes back with a new rate | |
873 | * for clk's parent then we propagate up to clk's parent and set it's | |
874 | * rate. Upward propagation will continue until either a clk does not | |
875 | * support the CLK_SET_RATE_PARENT flag or .round_rate stops requesting | |
876 | * changes to clk's parent_rate. If there is a failure during upstream | |
877 | * propagation then clk_set_rate will unwind and restore each clk's rate | |
878 | * that had been successfully changed. Afterwards a rate change abort | |
879 | * notification will be propagated downstream, starting from the clk | |
880 | * that failed. | |
881 | * | |
882 | * At the end of all of the rate setting, clk_set_rate internally calls | |
883 | * __clk_recalc_rates and propagates the rate changes downstream, | |
884 | * starting from the highest clk whose rate was changed. This has the | |
885 | * added benefit of propagating post-rate change notifiers. | |
886 | * | |
887 | * Note that while post-rate change and rate change abort notifications | |
888 | * are guaranteed to be sent to a clk only once per call to | |
889 | * clk_set_rate, pre-change notifications will be sent for every clk | |
890 | * whose rate is changed. Stacking pre-change notifications is noisy | |
891 | * for the drivers subscribed to them, but this allows drivers to react | |
892 | * to intermediate clk rate changes up until the point where the final | |
893 | * rate is achieved at the end of upstream propagation. | |
894 | * | |
895 | * Returns 0 on success, -EERROR otherwise. | |
896 | */ | |
897 | int 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 | /* calculate new rates and get the topmost changed clock */ | |
910 | top = clk_calc_new_rates(clk, rate); | |
911 | if (!top) { | |
912 | ret = -EINVAL; | |
913 | goto out; | |
914 | } | |
915 | ||
916 | /* notify that we are about to change rates */ | |
917 | fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); | |
918 | if (fail_clk) { | |
919 | pr_warn("%s: failed to set %s rate\n", __func__, | |
920 | fail_clk->name); | |
921 | clk_propagate_rate_change(top, ABORT_RATE_CHANGE); | |
922 | ret = -EBUSY; | |
923 | goto out; | |
924 | } | |
925 | ||
926 | /* change the rates */ | |
927 | clk_change_rate(top); | |
928 | ||
929 | mutex_unlock(&prepare_lock); | |
930 | ||
931 | return 0; | |
932 | out: | |
933 | mutex_unlock(&prepare_lock); | |
934 | ||
935 | return ret; | |
936 | } | |
937 | EXPORT_SYMBOL_GPL(clk_set_rate); | |
938 | ||
939 | /** | |
940 | * clk_get_parent - return the parent of a clk | |
941 | * @clk: the clk whose parent gets returned | |
942 | * | |
943 | * Simply returns clk->parent. Returns NULL if clk is NULL. | |
944 | */ | |
945 | struct clk *clk_get_parent(struct clk *clk) | |
946 | { | |
947 | struct clk *parent; | |
948 | ||
949 | mutex_lock(&prepare_lock); | |
950 | parent = __clk_get_parent(clk); | |
951 | mutex_unlock(&prepare_lock); | |
952 | ||
953 | return parent; | |
954 | } | |
955 | EXPORT_SYMBOL_GPL(clk_get_parent); | |
956 | ||
957 | /* | |
958 | * .get_parent is mandatory for clocks with multiple possible parents. It is | |
959 | * optional for single-parent clocks. Always call .get_parent if it is | |
960 | * available and WARN if it is missing for multi-parent clocks. | |
961 | * | |
962 | * For single-parent clocks without .get_parent, first check to see if the | |
963 | * .parents array exists, and if so use it to avoid an expensive tree | |
964 | * traversal. If .parents does not exist then walk the tree with __clk_lookup. | |
965 | */ | |
966 | static struct clk *__clk_init_parent(struct clk *clk) | |
967 | { | |
968 | struct clk *ret = NULL; | |
969 | u8 index; | |
970 | ||
971 | /* handle the trivial cases */ | |
972 | ||
973 | if (!clk->num_parents) | |
974 | goto out; | |
975 | ||
976 | if (clk->num_parents == 1) { | |
977 | if (IS_ERR_OR_NULL(clk->parent)) | |
978 | ret = clk->parent = __clk_lookup(clk->parent_names[0]); | |
979 | ret = clk->parent; | |
980 | goto out; | |
981 | } | |
982 | ||
983 | if (!clk->ops->get_parent) { | |
984 | WARN(!clk->ops->get_parent, | |
985 | "%s: multi-parent clocks must implement .get_parent\n", | |
986 | __func__); | |
987 | goto out; | |
988 | }; | |
989 | ||
990 | /* | |
991 | * Do our best to cache parent clocks in clk->parents. This prevents | |
992 | * unnecessary and expensive calls to __clk_lookup. We don't set | |
993 | * clk->parent here; that is done by the calling function | |
994 | */ | |
995 | ||
996 | index = clk->ops->get_parent(clk->hw); | |
997 | ||
998 | if (!clk->parents) | |
999 | clk->parents = | |
1000 | kmalloc((sizeof(struct clk*) * clk->num_parents), | |
1001 | GFP_KERNEL); | |
1002 | ||
1003 | if (!clk->parents) | |
1004 | ret = __clk_lookup(clk->parent_names[index]); | |
1005 | else if (!clk->parents[index]) | |
1006 | ret = clk->parents[index] = | |
1007 | __clk_lookup(clk->parent_names[index]); | |
1008 | else | |
1009 | ret = clk->parents[index]; | |
1010 | ||
1011 | out: | |
1012 | return ret; | |
1013 | } | |
1014 | ||
1015 | void __clk_reparent(struct clk *clk, struct clk *new_parent) | |
1016 | { | |
1017 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
1018 | struct dentry *d; | |
1019 | struct dentry *new_parent_d; | |
1020 | #endif | |
1021 | ||
1022 | if (!clk || !new_parent) | |
1023 | return; | |
1024 | ||
1025 | hlist_del(&clk->child_node); | |
1026 | ||
1027 | if (new_parent) | |
1028 | hlist_add_head(&clk->child_node, &new_parent->children); | |
1029 | else | |
1030 | hlist_add_head(&clk->child_node, &clk_orphan_list); | |
1031 | ||
1032 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
1033 | if (!inited) | |
1034 | goto out; | |
1035 | ||
1036 | if (new_parent) | |
1037 | new_parent_d = new_parent->dentry; | |
1038 | else | |
1039 | new_parent_d = orphandir; | |
1040 | ||
1041 | d = debugfs_rename(clk->dentry->d_parent, clk->dentry, | |
1042 | new_parent_d, clk->name); | |
1043 | if (d) | |
1044 | clk->dentry = d; | |
1045 | else | |
1046 | pr_debug("%s: failed to rename debugfs entry for %s\n", | |
1047 | __func__, clk->name); | |
1048 | out: | |
1049 | #endif | |
1050 | ||
1051 | clk->parent = new_parent; | |
1052 | ||
1053 | __clk_recalc_rates(clk, POST_RATE_CHANGE); | |
1054 | } | |
1055 | ||
1056 | static int __clk_set_parent(struct clk *clk, struct clk *parent) | |
1057 | { | |
1058 | struct clk *old_parent; | |
1059 | unsigned long flags; | |
1060 | int ret = -EINVAL; | |
1061 | u8 i; | |
1062 | ||
1063 | old_parent = clk->parent; | |
1064 | ||
1065 | /* find index of new parent clock using cached parent ptrs */ | |
1066 | for (i = 0; i < clk->num_parents; i++) | |
1067 | if (clk->parents[i] == parent) | |
1068 | break; | |
1069 | ||
1070 | /* | |
1071 | * find index of new parent clock using string name comparison | |
1072 | * also try to cache the parent to avoid future calls to __clk_lookup | |
1073 | */ | |
1074 | if (i == clk->num_parents) | |
1075 | for (i = 0; i < clk->num_parents; i++) | |
1076 | if (!strcmp(clk->parent_names[i], parent->name)) { | |
1077 | clk->parents[i] = __clk_lookup(parent->name); | |
1078 | break; | |
1079 | } | |
1080 | ||
1081 | if (i == clk->num_parents) { | |
1082 | pr_debug("%s: clock %s is not a possible parent of clock %s\n", | |
1083 | __func__, parent->name, clk->name); | |
1084 | goto out; | |
1085 | } | |
1086 | ||
1087 | /* migrate prepare and enable */ | |
1088 | if (clk->prepare_count) | |
1089 | __clk_prepare(parent); | |
1090 | ||
1091 | /* FIXME replace with clk_is_enabled(clk) someday */ | |
1092 | spin_lock_irqsave(&enable_lock, flags); | |
1093 | if (clk->enable_count) | |
1094 | __clk_enable(parent); | |
1095 | spin_unlock_irqrestore(&enable_lock, flags); | |
1096 | ||
1097 | /* change clock input source */ | |
1098 | ret = clk->ops->set_parent(clk->hw, i); | |
1099 | ||
1100 | /* clean up old prepare and enable */ | |
1101 | spin_lock_irqsave(&enable_lock, flags); | |
1102 | if (clk->enable_count) | |
1103 | __clk_disable(old_parent); | |
1104 | spin_unlock_irqrestore(&enable_lock, flags); | |
1105 | ||
1106 | if (clk->prepare_count) | |
1107 | __clk_unprepare(old_parent); | |
1108 | ||
1109 | out: | |
1110 | return ret; | |
1111 | } | |
1112 | ||
1113 | /** | |
1114 | * clk_set_parent - switch the parent of a mux clk | |
1115 | * @clk: the mux clk whose input we are switching | |
1116 | * @parent: the new input to clk | |
1117 | * | |
1118 | * Re-parent clk to use parent as it's new input source. If clk has the | |
1119 | * CLK_SET_PARENT_GATE flag set then clk must be gated for this | |
1120 | * operation to succeed. After successfully changing clk's parent | |
1121 | * clk_set_parent will update the clk topology, sysfs topology and | |
1122 | * propagate rate recalculation via __clk_recalc_rates. Returns 0 on | |
1123 | * success, -EERROR otherwise. | |
1124 | */ | |
1125 | int clk_set_parent(struct clk *clk, struct clk *parent) | |
1126 | { | |
1127 | int ret = 0; | |
1128 | ||
1129 | if (!clk || !clk->ops) | |
1130 | return -EINVAL; | |
1131 | ||
1132 | if (!clk->ops->set_parent) | |
1133 | return -ENOSYS; | |
1134 | ||
1135 | /* prevent racing with updates to the clock topology */ | |
1136 | mutex_lock(&prepare_lock); | |
1137 | ||
1138 | if (clk->parent == parent) | |
1139 | goto out; | |
1140 | ||
1141 | /* propagate PRE_RATE_CHANGE notifications */ | |
1142 | if (clk->notifier_count) | |
1143 | ret = __clk_speculate_rates(clk, parent->rate); | |
1144 | ||
1145 | /* abort if a driver objects */ | |
1146 | if (ret == NOTIFY_STOP) | |
1147 | goto out; | |
1148 | ||
1149 | /* only re-parent if the clock is not in use */ | |
1150 | if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) | |
1151 | ret = -EBUSY; | |
1152 | else | |
1153 | ret = __clk_set_parent(clk, parent); | |
1154 | ||
1155 | /* propagate ABORT_RATE_CHANGE if .set_parent failed */ | |
1156 | if (ret) { | |
1157 | __clk_recalc_rates(clk, ABORT_RATE_CHANGE); | |
1158 | goto out; | |
1159 | } | |
1160 | ||
1161 | /* propagate rate recalculation downstream */ | |
1162 | __clk_reparent(clk, parent); | |
1163 | ||
1164 | out: | |
1165 | mutex_unlock(&prepare_lock); | |
1166 | ||
1167 | return ret; | |
1168 | } | |
1169 | EXPORT_SYMBOL_GPL(clk_set_parent); | |
1170 | ||
1171 | /** | |
1172 | * __clk_init - initialize the data structures in a struct clk | |
1173 | * @dev: device initializing this clk, placeholder for now | |
1174 | * @clk: clk being initialized | |
1175 | * | |
1176 | * Initializes the lists in struct clk, queries the hardware for the | |
1177 | * parent and rate and sets them both. | |
1178 | * | |
1179 | * Any struct clk passed into __clk_init must have the following members | |
1180 | * populated: | |
1181 | * .name | |
1182 | * .ops | |
1183 | * .hw | |
1184 | * .parent_names | |
1185 | * .num_parents | |
1186 | * .flags | |
1187 | * | |
1188 | * Essentially, everything that would normally be passed into clk_register is | |
1189 | * assumed to be initialized already in __clk_init. The other members may be | |
1190 | * populated, but are optional. | |
1191 | * | |
1192 | * __clk_init is only exposed via clk-private.h and is intended for use with | |
1193 | * very large numbers of clocks that need to be statically initialized. It is | |
1194 | * a layering violation to include clk-private.h from any code which implements | |
1195 | * a clock's .ops; as such any statically initialized clock data MUST be in a | |
1196 | * separate C file from the logic that implements it's operations. | |
1197 | */ | |
1198 | void __clk_init(struct device *dev, struct clk *clk) | |
1199 | { | |
1200 | int i; | |
1201 | struct clk *orphan; | |
1202 | struct hlist_node *tmp, *tmp2; | |
1203 | ||
1204 | if (!clk) | |
1205 | return; | |
1206 | ||
1207 | mutex_lock(&prepare_lock); | |
1208 | ||
1209 | /* check to see if a clock with this name is already registered */ | |
1210 | if (__clk_lookup(clk->name)) | |
1211 | goto out; | |
1212 | ||
1213 | /* throw a WARN if any entries in parent_names are NULL */ | |
1214 | for (i = 0; i < clk->num_parents; i++) | |
1215 | WARN(!clk->parent_names[i], | |
1216 | "%s: invalid NULL in %s's .parent_names\n", | |
1217 | __func__, clk->name); | |
1218 | ||
1219 | /* | |
1220 | * Allocate an array of struct clk *'s to avoid unnecessary string | |
1221 | * look-ups of clk's possible parents. This can fail for clocks passed | |
1222 | * in to clk_init during early boot; thus any access to clk->parents[] | |
1223 | * must always check for a NULL pointer and try to populate it if | |
1224 | * necessary. | |
1225 | * | |
1226 | * If clk->parents is not NULL we skip this entire block. This allows | |
1227 | * for clock drivers to statically initialize clk->parents. | |
1228 | */ | |
1229 | if (clk->num_parents && !clk->parents) { | |
1230 | clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents), | |
1231 | GFP_KERNEL); | |
1232 | /* | |
1233 | * __clk_lookup returns NULL for parents that have not been | |
1234 | * clk_init'd; thus any access to clk->parents[] must check | |
1235 | * for a NULL pointer. We can always perform lazy lookups for | |
1236 | * missing parents later on. | |
1237 | */ | |
1238 | if (clk->parents) | |
1239 | for (i = 0; i < clk->num_parents; i++) | |
1240 | clk->parents[i] = | |
1241 | __clk_lookup(clk->parent_names[i]); | |
1242 | } | |
1243 | ||
1244 | clk->parent = __clk_init_parent(clk); | |
1245 | ||
1246 | /* | |
1247 | * Populate clk->parent if parent has already been __clk_init'd. If | |
1248 | * parent has not yet been __clk_init'd then place clk in the orphan | |
1249 | * list. If clk has set the CLK_IS_ROOT flag then place it in the root | |
1250 | * clk list. | |
1251 | * | |
1252 | * Every time a new clk is clk_init'd then we walk the list of orphan | |
1253 | * clocks and re-parent any that are children of the clock currently | |
1254 | * being clk_init'd. | |
1255 | */ | |
1256 | if (clk->parent) | |
1257 | hlist_add_head(&clk->child_node, | |
1258 | &clk->parent->children); | |
1259 | else if (clk->flags & CLK_IS_ROOT) | |
1260 | hlist_add_head(&clk->child_node, &clk_root_list); | |
1261 | else | |
1262 | hlist_add_head(&clk->child_node, &clk_orphan_list); | |
1263 | ||
1264 | /* | |
1265 | * Set clk's rate. The preferred method is to use .recalc_rate. For | |
1266 | * simple clocks and lazy developers the default fallback is to use the | |
1267 | * parent's rate. If a clock doesn't have a parent (or is orphaned) | |
1268 | * then rate is set to zero. | |
1269 | */ | |
1270 | if (clk->ops->recalc_rate) | |
1271 | clk->rate = clk->ops->recalc_rate(clk->hw, | |
1272 | __clk_get_rate(clk->parent)); | |
1273 | else if (clk->parent) | |
1274 | clk->rate = clk->parent->rate; | |
1275 | else | |
1276 | clk->rate = 0; | |
1277 | ||
1278 | /* | |
1279 | * walk the list of orphan clocks and reparent any that are children of | |
1280 | * this clock | |
1281 | */ | |
1282 | hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) | |
1283 | for (i = 0; i < orphan->num_parents; i++) | |
1284 | if (!strcmp(clk->name, orphan->parent_names[i])) { | |
1285 | __clk_reparent(orphan, clk); | |
1286 | break; | |
1287 | } | |
1288 | ||
1289 | /* | |
1290 | * optional platform-specific magic | |
1291 | * | |
1292 | * The .init callback is not used by any of the basic clock types, but | |
1293 | * exists for weird hardware that must perform initialization magic. | |
1294 | * Please consider other ways of solving initialization problems before | |
1295 | * using this callback, as it's use is discouraged. | |
1296 | */ | |
1297 | if (clk->ops->init) | |
1298 | clk->ops->init(clk->hw); | |
1299 | ||
1300 | clk_debug_register(clk); | |
1301 | ||
1302 | out: | |
1303 | mutex_unlock(&prepare_lock); | |
1304 | ||
1305 | return; | |
1306 | } | |
1307 | ||
1308 | /** | |
1309 | * clk_register - allocate a new clock, register it and return an opaque cookie | |
1310 | * @dev: device that is registering this clock | |
1311 | * @name: clock name | |
1312 | * @ops: operations this clock supports | |
1313 | * @hw: link to hardware-specific clock data | |
1314 | * @parent_names: array of string names for all possible parents | |
1315 | * @num_parents: number of possible parents | |
1316 | * @flags: framework-level hints and quirks | |
1317 | * | |
1318 | * clk_register is the primary interface for populating the clock tree with new | |
1319 | * clock nodes. It returns a pointer to the newly allocated struct clk which | |
1320 | * cannot be dereferenced by driver code but may be used in conjuction with the | |
1321 | * rest of the clock API. | |
1322 | */ | |
1323 | struct clk *clk_register(struct device *dev, const char *name, | |
1324 | const struct clk_ops *ops, struct clk_hw *hw, | |
1325 | char **parent_names, u8 num_parents, unsigned long flags) | |
1326 | { | |
1327 | struct clk *clk; | |
1328 | ||
1329 | clk = kzalloc(sizeof(*clk), GFP_KERNEL); | |
1330 | if (!clk) | |
1331 | return NULL; | |
1332 | ||
1333 | clk->name = name; | |
1334 | clk->ops = ops; | |
1335 | clk->hw = hw; | |
1336 | clk->flags = flags; | |
1337 | clk->parent_names = parent_names; | |
1338 | clk->num_parents = num_parents; | |
1339 | hw->clk = clk; | |
1340 | ||
1341 | __clk_init(dev, clk); | |
1342 | ||
1343 | return clk; | |
1344 | } | |
1345 | EXPORT_SYMBOL_GPL(clk_register); | |
1346 | ||
1347 | /*** clk rate change notifiers ***/ | |
1348 | ||
1349 | /** | |
1350 | * clk_notifier_register - add a clk rate change notifier | |
1351 | * @clk: struct clk * to watch | |
1352 | * @nb: struct notifier_block * with callback info | |
1353 | * | |
1354 | * Request notification when clk's rate changes. This uses an SRCU | |
1355 | * notifier because we want it to block and notifier unregistrations are | |
1356 | * uncommon. The callbacks associated with the notifier must not | |
1357 | * re-enter into the clk framework by calling any top-level clk APIs; | |
1358 | * this will cause a nested prepare_lock mutex. | |
1359 | * | |
1360 | * Pre-change notifier callbacks will be passed the current, pre-change | |
1361 | * rate of the clk via struct clk_notifier_data.old_rate. The new, | |
1362 | * post-change rate of the clk is passed via struct | |
1363 | * clk_notifier_data.new_rate. | |
1364 | * | |
1365 | * Post-change notifiers will pass the now-current, post-change rate of | |
1366 | * the clk in both struct clk_notifier_data.old_rate and struct | |
1367 | * clk_notifier_data.new_rate. | |
1368 | * | |
1369 | * Abort-change notifiers are effectively the opposite of pre-change | |
1370 | * notifiers: the original pre-change clk rate is passed in via struct | |
1371 | * clk_notifier_data.new_rate and the failed post-change rate is passed | |
1372 | * in via struct clk_notifier_data.old_rate. | |
1373 | * | |
1374 | * clk_notifier_register() must be called from non-atomic context. | |
1375 | * Returns -EINVAL if called with null arguments, -ENOMEM upon | |
1376 | * allocation failure; otherwise, passes along the return value of | |
1377 | * srcu_notifier_chain_register(). | |
1378 | */ | |
1379 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb) | |
1380 | { | |
1381 | struct clk_notifier *cn; | |
1382 | int ret = -ENOMEM; | |
1383 | ||
1384 | if (!clk || !nb) | |
1385 | return -EINVAL; | |
1386 | ||
1387 | mutex_lock(&prepare_lock); | |
1388 | ||
1389 | /* search the list of notifiers for this clk */ | |
1390 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1391 | if (cn->clk == clk) | |
1392 | break; | |
1393 | ||
1394 | /* if clk wasn't in the notifier list, allocate new clk_notifier */ | |
1395 | if (cn->clk != clk) { | |
1396 | cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); | |
1397 | if (!cn) | |
1398 | goto out; | |
1399 | ||
1400 | cn->clk = clk; | |
1401 | srcu_init_notifier_head(&cn->notifier_head); | |
1402 | ||
1403 | list_add(&cn->node, &clk_notifier_list); | |
1404 | } | |
1405 | ||
1406 | ret = srcu_notifier_chain_register(&cn->notifier_head, nb); | |
1407 | ||
1408 | clk->notifier_count++; | |
1409 | ||
1410 | out: | |
1411 | mutex_unlock(&prepare_lock); | |
1412 | ||
1413 | return ret; | |
1414 | } | |
1415 | EXPORT_SYMBOL_GPL(clk_notifier_register); | |
1416 | ||
1417 | /** | |
1418 | * clk_notifier_unregister - remove a clk rate change notifier | |
1419 | * @clk: struct clk * | |
1420 | * @nb: struct notifier_block * with callback info | |
1421 | * | |
1422 | * Request no further notification for changes to 'clk' and frees memory | |
1423 | * allocated in clk_notifier_register. | |
1424 | * | |
1425 | * Returns -EINVAL if called with null arguments; otherwise, passes | |
1426 | * along the return value of srcu_notifier_chain_unregister(). | |
1427 | */ | |
1428 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) | |
1429 | { | |
1430 | struct clk_notifier *cn = NULL; | |
1431 | int ret = -EINVAL; | |
1432 | ||
1433 | if (!clk || !nb) | |
1434 | return -EINVAL; | |
1435 | ||
1436 | mutex_lock(&prepare_lock); | |
1437 | ||
1438 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1439 | if (cn->clk == clk) | |
1440 | break; | |
1441 | ||
1442 | if (cn->clk == clk) { | |
1443 | ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); | |
1444 | ||
1445 | clk->notifier_count--; | |
1446 | ||
1447 | /* XXX the notifier code should handle this better */ | |
1448 | if (!cn->notifier_head.head) { | |
1449 | srcu_cleanup_notifier_head(&cn->notifier_head); | |
1450 | kfree(cn); | |
1451 | } | |
1452 | ||
1453 | } else { | |
1454 | ret = -ENOENT; | |
1455 | } | |
1456 | ||
1457 | mutex_unlock(&prepare_lock); | |
1458 | ||
1459 | return ret; | |
1460 | } | |
1461 | EXPORT_SYMBOL_GPL(clk_notifier_unregister); |