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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; } | |
70d347e6 | 197 | #endif |
b2476490 | 198 | |
b2476490 MT |
199 | /* caller must hold prepare_lock */ |
200 | static 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 | ||
223 | unlock_out: | |
224 | spin_unlock_irqrestore(&enable_lock, flags); | |
225 | ||
226 | out: | |
227 | return; | |
228 | } | |
229 | ||
230 | static 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 | } | |
247 | late_initcall(clk_disable_unused); | |
b2476490 MT |
248 | |
249 | /*** helper functions ***/ | |
250 | ||
251 | inline const char *__clk_get_name(struct clk *clk) | |
252 | { | |
253 | return !clk ? NULL : clk->name; | |
254 | } | |
255 | ||
256 | inline struct clk_hw *__clk_get_hw(struct clk *clk) | |
257 | { | |
258 | return !clk ? NULL : clk->hw; | |
259 | } | |
260 | ||
261 | inline u8 __clk_get_num_parents(struct clk *clk) | |
262 | { | |
263 | return !clk ? -EINVAL : clk->num_parents; | |
264 | } | |
265 | ||
266 | inline struct clk *__clk_get_parent(struct clk *clk) | |
267 | { | |
268 | return !clk ? NULL : clk->parent; | |
269 | } | |
270 | ||
271 | inline int __clk_get_enable_count(struct clk *clk) | |
272 | { | |
273 | return !clk ? -EINVAL : clk->enable_count; | |
274 | } | |
275 | ||
276 | inline int __clk_get_prepare_count(struct clk *clk) | |
277 | { | |
278 | return !clk ? -EINVAL : clk->prepare_count; | |
279 | } | |
280 | ||
281 | unsigned long __clk_get_rate(struct clk *clk) | |
282 | { | |
283 | unsigned long ret; | |
284 | ||
285 | if (!clk) { | |
34e44fe8 | 286 | ret = 0; |
b2476490 MT |
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) | |
34e44fe8 | 296 | ret = 0; |
b2476490 MT |
297 | |
298 | out: | |
299 | return ret; | |
300 | } | |
301 | ||
302 | inline unsigned long __clk_get_flags(struct clk *clk) | |
303 | { | |
304 | return !clk ? -EINVAL : clk->flags; | |
305 | } | |
306 | ||
307 | int __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); | |
324 | out: | |
325 | return ret; | |
326 | } | |
327 | ||
328 | static 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 | ||
346 | struct 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 | ||
374 | void __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 | */ | |
404 | void clk_unprepare(struct clk *clk) | |
405 | { | |
406 | mutex_lock(&prepare_lock); | |
407 | __clk_unprepare(clk); | |
408 | mutex_unlock(&prepare_lock); | |
409 | } | |
410 | EXPORT_SYMBOL_GPL(clk_unprepare); | |
411 | ||
412 | int __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 | */ | |
450 | int 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 | } | |
460 | EXPORT_SYMBOL_GPL(clk_prepare); | |
461 | ||
462 | static 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 | */ | |
491 | void 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 | } | |
499 | EXPORT_SYMBOL_GPL(clk_disable); | |
500 | ||
501 | static 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 | */ | |
543 | int 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 | } | |
554 | EXPORT_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 | |
34e44fe8 | 561 | * clk is NULL then returns 0. |
b2476490 MT |
562 | */ |
563 | unsigned 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 | } | |
573 | EXPORT_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 | */ | |
581 | unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) | |
582 | { | |
81536e07 | 583 | unsigned long parent_rate = 0; |
b2476490 MT |
584 | |
585 | if (!clk) | |
586 | return -EINVAL; | |
587 | ||
f4d8af2e SG |
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 | } | |
b2476490 | 594 | |
81536e07 SG |
595 | if (clk->parent) |
596 | parent_rate = clk->parent->rate; | |
597 | ||
598 | return clk->ops->round_rate(clk->hw, rate, &parent_rate); | |
b2476490 MT |
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; | |
81536e07 | 768 | unsigned long best_parent_rate = 0; |
b2476490 MT |
769 | unsigned long new_rate; |
770 | ||
7452b219 MT |
771 | /* sanity */ |
772 | if (IS_ERR_OR_NULL(clk)) | |
773 | return NULL; | |
774 | ||
63f5c3b2 MT |
775 | /* save parent rate, if it exists */ |
776 | if (clk->parent) | |
777 | best_parent_rate = clk->parent->rate; | |
778 | ||
7452b219 MT |
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; | |
7452b219 | 784 | } |
63f5c3b2 MT |
785 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
786 | goto out; | |
7452b219 MT |
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); | |
b2476490 MT |
792 | return NULL; |
793 | } | |
794 | ||
7452b219 | 795 | if (!clk->ops->round_rate) { |
b2476490 | 796 | top = clk_calc_new_rates(clk->parent, rate); |
1b2f9903 | 797 | new_rate = clk->parent->new_rate; |
b2476490 MT |
798 | |
799 | goto out; | |
800 | } | |
801 | ||
7452b219 | 802 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
b2476490 MT |
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 | ||
810 | out: | |
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 | */ | |
821 | static 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 | */ | |
849 | static void clk_change_rate(struct clk *clk) | |
850 | { | |
851 | struct clk *child; | |
852 | unsigned long old_rate; | |
bf47b4fd | 853 | unsigned long best_parent_rate = 0; |
b2476490 MT |
854 | struct hlist_node *tmp; |
855 | ||
856 | old_rate = clk->rate; | |
857 | ||
bf47b4fd PM |
858 | if (clk->parent) |
859 | best_parent_rate = clk->parent->rate; | |
860 | ||
b2476490 | 861 | if (clk->ops->set_rate) |
bf47b4fd | 862 | clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate); |
b2476490 MT |
863 | |
864 | if (clk->ops->recalc_rate) | |
bf47b4fd | 865 | clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate); |
b2476490 | 866 | else |
bf47b4fd | 867 | clk->rate = best_parent_rate; |
b2476490 MT |
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 | * | |
5654dc94 | 881 | * In the simplest case clk_set_rate will only adjust the rate of clk. |
b2476490 | 882 | * |
5654dc94 MT |
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. | |
b2476490 | 891 | * |
5654dc94 MT |
892 | * Rate changes are accomplished via tree traversal that also recalculates the |
893 | * rates for the clocks and fires off POST_RATE_CHANGE notifiers. | |
b2476490 MT |
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 | ||
7e0fa1b5 | 909 | if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) { |
0e1c0301 VK |
910 | ret = -EBUSY; |
911 | goto out; | |
912 | } | |
913 | ||
b2476490 MT |
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; | |
937 | out: | |
938 | mutex_unlock(&prepare_lock); | |
939 | ||
940 | return ret; | |
941 | } | |
942 | EXPORT_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 | */ | |
950 | struct 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 | } | |
960 | EXPORT_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 | */ | |
971 | static 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 = | |
7975059d | 1005 | kzalloc((sizeof(struct clk*) * clk->num_parents), |
b2476490 MT |
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 | ||
1016 | out: | |
1017 | return ret; | |
1018 | } | |
1019 | ||
1020 | void __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); | |
1053 | out: | |
1054 | #endif | |
1055 | ||
1056 | clk->parent = new_parent; | |
1057 | ||
1058 | __clk_recalc_rates(clk, POST_RATE_CHANGE); | |
1059 | } | |
1060 | ||
1061 | static 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 | /* find index of new parent clock using cached parent ptrs */ | |
7975059d RN |
1071 | if (clk->parents) |
1072 | for (i = 0; i < clk->num_parents; i++) | |
1073 | if (clk->parents[i] == parent) | |
1074 | break; | |
1075 | else | |
1076 | clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), | |
1077 | GFP_KERNEL); | |
b2476490 MT |
1078 | |
1079 | /* | |
1080 | * find index of new parent clock using string name comparison | |
1081 | * also try to cache the parent to avoid future calls to __clk_lookup | |
1082 | */ | |
1083 | if (i == clk->num_parents) | |
1084 | for (i = 0; i < clk->num_parents; i++) | |
1085 | if (!strcmp(clk->parent_names[i], parent->name)) { | |
7975059d RN |
1086 | if (clk->parents) |
1087 | clk->parents[i] = __clk_lookup(parent->name); | |
b2476490 MT |
1088 | break; |
1089 | } | |
1090 | ||
1091 | if (i == clk->num_parents) { | |
1092 | pr_debug("%s: clock %s is not a possible parent of clock %s\n", | |
1093 | __func__, parent->name, clk->name); | |
1094 | goto out; | |
1095 | } | |
1096 | ||
1097 | /* migrate prepare and enable */ | |
1098 | if (clk->prepare_count) | |
1099 | __clk_prepare(parent); | |
1100 | ||
1101 | /* FIXME replace with clk_is_enabled(clk) someday */ | |
1102 | spin_lock_irqsave(&enable_lock, flags); | |
1103 | if (clk->enable_count) | |
1104 | __clk_enable(parent); | |
1105 | spin_unlock_irqrestore(&enable_lock, flags); | |
1106 | ||
1107 | /* change clock input source */ | |
1108 | ret = clk->ops->set_parent(clk->hw, i); | |
1109 | ||
1110 | /* clean up old prepare and enable */ | |
1111 | spin_lock_irqsave(&enable_lock, flags); | |
1112 | if (clk->enable_count) | |
1113 | __clk_disable(old_parent); | |
1114 | spin_unlock_irqrestore(&enable_lock, flags); | |
1115 | ||
1116 | if (clk->prepare_count) | |
1117 | __clk_unprepare(old_parent); | |
1118 | ||
1119 | out: | |
1120 | return ret; | |
1121 | } | |
1122 | ||
1123 | /** | |
1124 | * clk_set_parent - switch the parent of a mux clk | |
1125 | * @clk: the mux clk whose input we are switching | |
1126 | * @parent: the new input to clk | |
1127 | * | |
1128 | * Re-parent clk to use parent as it's new input source. If clk has the | |
1129 | * CLK_SET_PARENT_GATE flag set then clk must be gated for this | |
1130 | * operation to succeed. After successfully changing clk's parent | |
1131 | * clk_set_parent will update the clk topology, sysfs topology and | |
1132 | * propagate rate recalculation via __clk_recalc_rates. Returns 0 on | |
1133 | * success, -EERROR otherwise. | |
1134 | */ | |
1135 | int clk_set_parent(struct clk *clk, struct clk *parent) | |
1136 | { | |
1137 | int ret = 0; | |
1138 | ||
1139 | if (!clk || !clk->ops) | |
1140 | return -EINVAL; | |
1141 | ||
1142 | if (!clk->ops->set_parent) | |
1143 | return -ENOSYS; | |
1144 | ||
1145 | /* prevent racing with updates to the clock topology */ | |
1146 | mutex_lock(&prepare_lock); | |
1147 | ||
1148 | if (clk->parent == parent) | |
1149 | goto out; | |
1150 | ||
1151 | /* propagate PRE_RATE_CHANGE notifications */ | |
1152 | if (clk->notifier_count) | |
1153 | ret = __clk_speculate_rates(clk, parent->rate); | |
1154 | ||
1155 | /* abort if a driver objects */ | |
1156 | if (ret == NOTIFY_STOP) | |
1157 | goto out; | |
1158 | ||
1159 | /* only re-parent if the clock is not in use */ | |
1160 | if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) | |
1161 | ret = -EBUSY; | |
1162 | else | |
1163 | ret = __clk_set_parent(clk, parent); | |
1164 | ||
1165 | /* propagate ABORT_RATE_CHANGE if .set_parent failed */ | |
1166 | if (ret) { | |
1167 | __clk_recalc_rates(clk, ABORT_RATE_CHANGE); | |
1168 | goto out; | |
1169 | } | |
1170 | ||
1171 | /* propagate rate recalculation downstream */ | |
1172 | __clk_reparent(clk, parent); | |
1173 | ||
1174 | out: | |
1175 | mutex_unlock(&prepare_lock); | |
1176 | ||
1177 | return ret; | |
1178 | } | |
1179 | EXPORT_SYMBOL_GPL(clk_set_parent); | |
1180 | ||
1181 | /** | |
1182 | * __clk_init - initialize the data structures in a struct clk | |
1183 | * @dev: device initializing this clk, placeholder for now | |
1184 | * @clk: clk being initialized | |
1185 | * | |
1186 | * Initializes the lists in struct clk, queries the hardware for the | |
1187 | * parent and rate and sets them both. | |
b2476490 | 1188 | */ |
d1302a36 | 1189 | int __clk_init(struct device *dev, struct clk *clk) |
b2476490 | 1190 | { |
d1302a36 | 1191 | int i, ret = 0; |
b2476490 MT |
1192 | struct clk *orphan; |
1193 | struct hlist_node *tmp, *tmp2; | |
1194 | ||
1195 | if (!clk) | |
d1302a36 | 1196 | return -EINVAL; |
b2476490 MT |
1197 | |
1198 | mutex_lock(&prepare_lock); | |
1199 | ||
1200 | /* check to see if a clock with this name is already registered */ | |
d1302a36 MT |
1201 | if (__clk_lookup(clk->name)) { |
1202 | pr_debug("%s: clk %s already initialized\n", | |
1203 | __func__, clk->name); | |
1204 | ret = -EEXIST; | |
b2476490 | 1205 | goto out; |
d1302a36 | 1206 | } |
b2476490 | 1207 | |
d4d7e3dd MT |
1208 | /* check that clk_ops are sane. See Documentation/clk.txt */ |
1209 | if (clk->ops->set_rate && | |
1210 | !(clk->ops->round_rate && clk->ops->recalc_rate)) { | |
1211 | pr_warning("%s: %s must implement .round_rate & .recalc_rate\n", | |
1212 | __func__, clk->name); | |
d1302a36 | 1213 | ret = -EINVAL; |
d4d7e3dd MT |
1214 | goto out; |
1215 | } | |
1216 | ||
1217 | if (clk->ops->set_parent && !clk->ops->get_parent) { | |
1218 | pr_warning("%s: %s must implement .get_parent & .set_parent\n", | |
1219 | __func__, clk->name); | |
d1302a36 | 1220 | ret = -EINVAL; |
d4d7e3dd MT |
1221 | goto out; |
1222 | } | |
1223 | ||
b2476490 MT |
1224 | /* throw a WARN if any entries in parent_names are NULL */ |
1225 | for (i = 0; i < clk->num_parents; i++) | |
1226 | WARN(!clk->parent_names[i], | |
1227 | "%s: invalid NULL in %s's .parent_names\n", | |
1228 | __func__, clk->name); | |
1229 | ||
1230 | /* | |
1231 | * Allocate an array of struct clk *'s to avoid unnecessary string | |
1232 | * look-ups of clk's possible parents. This can fail for clocks passed | |
1233 | * in to clk_init during early boot; thus any access to clk->parents[] | |
1234 | * must always check for a NULL pointer and try to populate it if | |
1235 | * necessary. | |
1236 | * | |
1237 | * If clk->parents is not NULL we skip this entire block. This allows | |
1238 | * for clock drivers to statically initialize clk->parents. | |
1239 | */ | |
1240 | if (clk->num_parents && !clk->parents) { | |
1241 | clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents), | |
1242 | GFP_KERNEL); | |
1243 | /* | |
1244 | * __clk_lookup returns NULL for parents that have not been | |
1245 | * clk_init'd; thus any access to clk->parents[] must check | |
1246 | * for a NULL pointer. We can always perform lazy lookups for | |
1247 | * missing parents later on. | |
1248 | */ | |
1249 | if (clk->parents) | |
1250 | for (i = 0; i < clk->num_parents; i++) | |
1251 | clk->parents[i] = | |
1252 | __clk_lookup(clk->parent_names[i]); | |
1253 | } | |
1254 | ||
1255 | clk->parent = __clk_init_parent(clk); | |
1256 | ||
1257 | /* | |
1258 | * Populate clk->parent if parent has already been __clk_init'd. If | |
1259 | * parent has not yet been __clk_init'd then place clk in the orphan | |
1260 | * list. If clk has set the CLK_IS_ROOT flag then place it in the root | |
1261 | * clk list. | |
1262 | * | |
1263 | * Every time a new clk is clk_init'd then we walk the list of orphan | |
1264 | * clocks and re-parent any that are children of the clock currently | |
1265 | * being clk_init'd. | |
1266 | */ | |
1267 | if (clk->parent) | |
1268 | hlist_add_head(&clk->child_node, | |
1269 | &clk->parent->children); | |
1270 | else if (clk->flags & CLK_IS_ROOT) | |
1271 | hlist_add_head(&clk->child_node, &clk_root_list); | |
1272 | else | |
1273 | hlist_add_head(&clk->child_node, &clk_orphan_list); | |
1274 | ||
1275 | /* | |
1276 | * Set clk's rate. The preferred method is to use .recalc_rate. For | |
1277 | * simple clocks and lazy developers the default fallback is to use the | |
1278 | * parent's rate. If a clock doesn't have a parent (or is orphaned) | |
1279 | * then rate is set to zero. | |
1280 | */ | |
1281 | if (clk->ops->recalc_rate) | |
1282 | clk->rate = clk->ops->recalc_rate(clk->hw, | |
1283 | __clk_get_rate(clk->parent)); | |
1284 | else if (clk->parent) | |
1285 | clk->rate = clk->parent->rate; | |
1286 | else | |
1287 | clk->rate = 0; | |
1288 | ||
1289 | /* | |
1290 | * walk the list of orphan clocks and reparent any that are children of | |
1291 | * this clock | |
1292 | */ | |
1293 | hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) | |
1294 | for (i = 0; i < orphan->num_parents; i++) | |
1295 | if (!strcmp(clk->name, orphan->parent_names[i])) { | |
1296 | __clk_reparent(orphan, clk); | |
1297 | break; | |
1298 | } | |
1299 | ||
1300 | /* | |
1301 | * optional platform-specific magic | |
1302 | * | |
1303 | * The .init callback is not used by any of the basic clock types, but | |
1304 | * exists for weird hardware that must perform initialization magic. | |
1305 | * Please consider other ways of solving initialization problems before | |
1306 | * using this callback, as it's use is discouraged. | |
1307 | */ | |
1308 | if (clk->ops->init) | |
1309 | clk->ops->init(clk->hw); | |
1310 | ||
1311 | clk_debug_register(clk); | |
1312 | ||
1313 | out: | |
1314 | mutex_unlock(&prepare_lock); | |
1315 | ||
d1302a36 | 1316 | return ret; |
b2476490 MT |
1317 | } |
1318 | ||
0197b3ea SK |
1319 | /** |
1320 | * __clk_register - register a clock and return a cookie. | |
1321 | * | |
1322 | * Same as clk_register, except that the .clk field inside hw shall point to a | |
1323 | * preallocated (generally statically allocated) struct clk. None of the fields | |
1324 | * of the struct clk need to be initialized. | |
1325 | * | |
1326 | * The data pointed to by .init and .clk field shall NOT be marked as init | |
1327 | * data. | |
1328 | * | |
1329 | * __clk_register is only exposed via clk-private.h and is intended for use with | |
1330 | * very large numbers of clocks that need to be statically initialized. It is | |
1331 | * a layering violation to include clk-private.h from any code which implements | |
1332 | * a clock's .ops; as such any statically initialized clock data MUST be in a | |
1333 | * separate C file from the logic that implements it's operations. Returns 0 | |
1334 | * on success, otherwise an error code. | |
1335 | */ | |
1336 | struct clk *__clk_register(struct device *dev, struct clk_hw *hw) | |
1337 | { | |
1338 | int ret; | |
1339 | struct clk *clk; | |
1340 | ||
1341 | clk = hw->clk; | |
1342 | clk->name = hw->init->name; | |
1343 | clk->ops = hw->init->ops; | |
1344 | clk->hw = hw; | |
1345 | clk->flags = hw->init->flags; | |
1346 | clk->parent_names = hw->init->parent_names; | |
1347 | clk->num_parents = hw->init->num_parents; | |
1348 | ||
1349 | ret = __clk_init(dev, clk); | |
1350 | if (ret) | |
1351 | return ERR_PTR(ret); | |
1352 | ||
1353 | return clk; | |
1354 | } | |
1355 | EXPORT_SYMBOL_GPL(__clk_register); | |
1356 | ||
b2476490 MT |
1357 | /** |
1358 | * clk_register - allocate a new clock, register it and return an opaque cookie | |
1359 | * @dev: device that is registering this clock | |
b2476490 | 1360 | * @hw: link to hardware-specific clock data |
b2476490 MT |
1361 | * |
1362 | * clk_register is the primary interface for populating the clock tree with new | |
1363 | * clock nodes. It returns a pointer to the newly allocated struct clk which | |
1364 | * cannot be dereferenced by driver code but may be used in conjuction with the | |
d1302a36 MT |
1365 | * rest of the clock API. In the event of an error clk_register will return an |
1366 | * error code; drivers must test for an error code after calling clk_register. | |
b2476490 | 1367 | */ |
0197b3ea | 1368 | struct clk *clk_register(struct device *dev, struct clk_hw *hw) |
b2476490 | 1369 | { |
d1302a36 | 1370 | int i, ret; |
b2476490 MT |
1371 | struct clk *clk; |
1372 | ||
1373 | clk = kzalloc(sizeof(*clk), GFP_KERNEL); | |
d1302a36 MT |
1374 | if (!clk) { |
1375 | pr_err("%s: could not allocate clk\n", __func__); | |
1376 | ret = -ENOMEM; | |
1377 | goto fail_out; | |
1378 | } | |
b2476490 | 1379 | |
0197b3ea SK |
1380 | clk->name = kstrdup(hw->init->name, GFP_KERNEL); |
1381 | if (!clk->name) { | |
1382 | pr_err("%s: could not allocate clk->name\n", __func__); | |
1383 | ret = -ENOMEM; | |
1384 | goto fail_name; | |
1385 | } | |
1386 | clk->ops = hw->init->ops; | |
b2476490 | 1387 | clk->hw = hw; |
0197b3ea SK |
1388 | clk->flags = hw->init->flags; |
1389 | clk->num_parents = hw->init->num_parents; | |
b2476490 MT |
1390 | hw->clk = clk; |
1391 | ||
d1302a36 | 1392 | /* allocate local copy in case parent_names is __initdata */ |
0197b3ea | 1393 | clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents), |
d1302a36 MT |
1394 | GFP_KERNEL); |
1395 | ||
1396 | if (!clk->parent_names) { | |
1397 | pr_err("%s: could not allocate clk->parent_names\n", __func__); | |
1398 | ret = -ENOMEM; | |
1399 | goto fail_parent_names; | |
1400 | } | |
1401 | ||
1402 | ||
1403 | /* copy each string name in case parent_names is __initdata */ | |
0197b3ea SK |
1404 | for (i = 0; i < clk->num_parents; i++) { |
1405 | clk->parent_names[i] = kstrdup(hw->init->parent_names[i], | |
1406 | GFP_KERNEL); | |
d1302a36 MT |
1407 | if (!clk->parent_names[i]) { |
1408 | pr_err("%s: could not copy parent_names\n", __func__); | |
1409 | ret = -ENOMEM; | |
1410 | goto fail_parent_names_copy; | |
1411 | } | |
1412 | } | |
1413 | ||
1414 | ret = __clk_init(dev, clk); | |
1415 | if (!ret) | |
1416 | return clk; | |
b2476490 | 1417 | |
d1302a36 MT |
1418 | fail_parent_names_copy: |
1419 | while (--i >= 0) | |
1420 | kfree(clk->parent_names[i]); | |
1421 | kfree(clk->parent_names); | |
1422 | fail_parent_names: | |
0197b3ea SK |
1423 | kfree(clk->name); |
1424 | fail_name: | |
d1302a36 MT |
1425 | kfree(clk); |
1426 | fail_out: | |
1427 | return ERR_PTR(ret); | |
b2476490 MT |
1428 | } |
1429 | EXPORT_SYMBOL_GPL(clk_register); | |
1430 | ||
1df5c939 MB |
1431 | /** |
1432 | * clk_unregister - unregister a currently registered clock | |
1433 | * @clk: clock to unregister | |
1434 | * | |
1435 | * Currently unimplemented. | |
1436 | */ | |
1437 | void clk_unregister(struct clk *clk) {} | |
1438 | EXPORT_SYMBOL_GPL(clk_unregister); | |
1439 | ||
b2476490 MT |
1440 | /*** clk rate change notifiers ***/ |
1441 | ||
1442 | /** | |
1443 | * clk_notifier_register - add a clk rate change notifier | |
1444 | * @clk: struct clk * to watch | |
1445 | * @nb: struct notifier_block * with callback info | |
1446 | * | |
1447 | * Request notification when clk's rate changes. This uses an SRCU | |
1448 | * notifier because we want it to block and notifier unregistrations are | |
1449 | * uncommon. The callbacks associated with the notifier must not | |
1450 | * re-enter into the clk framework by calling any top-level clk APIs; | |
1451 | * this will cause a nested prepare_lock mutex. | |
1452 | * | |
1453 | * Pre-change notifier callbacks will be passed the current, pre-change | |
1454 | * rate of the clk via struct clk_notifier_data.old_rate. The new, | |
1455 | * post-change rate of the clk is passed via struct | |
1456 | * clk_notifier_data.new_rate. | |
1457 | * | |
1458 | * Post-change notifiers will pass the now-current, post-change rate of | |
1459 | * the clk in both struct clk_notifier_data.old_rate and struct | |
1460 | * clk_notifier_data.new_rate. | |
1461 | * | |
1462 | * Abort-change notifiers are effectively the opposite of pre-change | |
1463 | * notifiers: the original pre-change clk rate is passed in via struct | |
1464 | * clk_notifier_data.new_rate and the failed post-change rate is passed | |
1465 | * in via struct clk_notifier_data.old_rate. | |
1466 | * | |
1467 | * clk_notifier_register() must be called from non-atomic context. | |
1468 | * Returns -EINVAL if called with null arguments, -ENOMEM upon | |
1469 | * allocation failure; otherwise, passes along the return value of | |
1470 | * srcu_notifier_chain_register(). | |
1471 | */ | |
1472 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb) | |
1473 | { | |
1474 | struct clk_notifier *cn; | |
1475 | int ret = -ENOMEM; | |
1476 | ||
1477 | if (!clk || !nb) | |
1478 | return -EINVAL; | |
1479 | ||
1480 | mutex_lock(&prepare_lock); | |
1481 | ||
1482 | /* search the list of notifiers for this clk */ | |
1483 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1484 | if (cn->clk == clk) | |
1485 | break; | |
1486 | ||
1487 | /* if clk wasn't in the notifier list, allocate new clk_notifier */ | |
1488 | if (cn->clk != clk) { | |
1489 | cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); | |
1490 | if (!cn) | |
1491 | goto out; | |
1492 | ||
1493 | cn->clk = clk; | |
1494 | srcu_init_notifier_head(&cn->notifier_head); | |
1495 | ||
1496 | list_add(&cn->node, &clk_notifier_list); | |
1497 | } | |
1498 | ||
1499 | ret = srcu_notifier_chain_register(&cn->notifier_head, nb); | |
1500 | ||
1501 | clk->notifier_count++; | |
1502 | ||
1503 | out: | |
1504 | mutex_unlock(&prepare_lock); | |
1505 | ||
1506 | return ret; | |
1507 | } | |
1508 | EXPORT_SYMBOL_GPL(clk_notifier_register); | |
1509 | ||
1510 | /** | |
1511 | * clk_notifier_unregister - remove a clk rate change notifier | |
1512 | * @clk: struct clk * | |
1513 | * @nb: struct notifier_block * with callback info | |
1514 | * | |
1515 | * Request no further notification for changes to 'clk' and frees memory | |
1516 | * allocated in clk_notifier_register. | |
1517 | * | |
1518 | * Returns -EINVAL if called with null arguments; otherwise, passes | |
1519 | * along the return value of srcu_notifier_chain_unregister(). | |
1520 | */ | |
1521 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) | |
1522 | { | |
1523 | struct clk_notifier *cn = NULL; | |
1524 | int ret = -EINVAL; | |
1525 | ||
1526 | if (!clk || !nb) | |
1527 | return -EINVAL; | |
1528 | ||
1529 | mutex_lock(&prepare_lock); | |
1530 | ||
1531 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1532 | if (cn->clk == clk) | |
1533 | break; | |
1534 | ||
1535 | if (cn->clk == clk) { | |
1536 | ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); | |
1537 | ||
1538 | clk->notifier_count--; | |
1539 | ||
1540 | /* XXX the notifier code should handle this better */ | |
1541 | if (!cn->notifier_head.head) { | |
1542 | srcu_cleanup_notifier_head(&cn->notifier_head); | |
1543 | kfree(cn); | |
1544 | } | |
1545 | ||
1546 | } else { | |
1547 | ret = -ENOENT; | |
1548 | } | |
1549 | ||
1550 | mutex_unlock(&prepare_lock); | |
1551 | ||
1552 | return ret; | |
1553 | } | |
1554 | EXPORT_SYMBOL_GPL(clk_notifier_unregister); |