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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> | |
766e6a4e | 19 | #include <linux/of.h> |
b2476490 MT |
20 | |
21 | static DEFINE_SPINLOCK(enable_lock); | |
22 | static DEFINE_MUTEX(prepare_lock); | |
23 | ||
24 | static HLIST_HEAD(clk_root_list); | |
25 | static HLIST_HEAD(clk_orphan_list); | |
26 | static LIST_HEAD(clk_notifier_list); | |
27 | ||
28 | /*** debugfs support ***/ | |
29 | ||
30 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
31 | #include <linux/debugfs.h> | |
32 | ||
33 | static struct dentry *rootdir; | |
34 | static struct dentry *orphandir; | |
35 | static int inited = 0; | |
36 | ||
37 | /* caller must hold prepare_lock */ | |
38 | static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) | |
39 | { | |
40 | struct dentry *d; | |
41 | int ret = -ENOMEM; | |
42 | ||
43 | if (!clk || !pdentry) { | |
44 | ret = -EINVAL; | |
45 | goto out; | |
46 | } | |
47 | ||
48 | d = debugfs_create_dir(clk->name, pdentry); | |
49 | if (!d) | |
50 | goto out; | |
51 | ||
52 | clk->dentry = d; | |
53 | ||
54 | d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry, | |
55 | (u32 *)&clk->rate); | |
56 | if (!d) | |
57 | goto err_out; | |
58 | ||
59 | d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry, | |
60 | (u32 *)&clk->flags); | |
61 | if (!d) | |
62 | goto err_out; | |
63 | ||
64 | d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry, | |
65 | (u32 *)&clk->prepare_count); | |
66 | if (!d) | |
67 | goto err_out; | |
68 | ||
69 | d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry, | |
70 | (u32 *)&clk->enable_count); | |
71 | if (!d) | |
72 | goto err_out; | |
73 | ||
74 | d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry, | |
75 | (u32 *)&clk->notifier_count); | |
76 | if (!d) | |
77 | goto err_out; | |
78 | ||
79 | ret = 0; | |
80 | goto out; | |
81 | ||
82 | err_out: | |
83 | debugfs_remove(clk->dentry); | |
84 | out: | |
85 | return ret; | |
86 | } | |
87 | ||
88 | /* caller must hold prepare_lock */ | |
89 | static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry) | |
90 | { | |
91 | struct clk *child; | |
92 | struct hlist_node *tmp; | |
93 | int ret = -EINVAL;; | |
94 | ||
95 | if (!clk || !pdentry) | |
96 | goto out; | |
97 | ||
98 | ret = clk_debug_create_one(clk, pdentry); | |
99 | ||
100 | if (ret) | |
101 | goto out; | |
102 | ||
103 | hlist_for_each_entry(child, tmp, &clk->children, child_node) | |
104 | clk_debug_create_subtree(child, clk->dentry); | |
105 | ||
106 | ret = 0; | |
107 | out: | |
108 | return ret; | |
109 | } | |
110 | ||
111 | /** | |
112 | * clk_debug_register - add a clk node to the debugfs clk tree | |
113 | * @clk: the clk being added to the debugfs clk tree | |
114 | * | |
115 | * Dynamically adds a clk to the debugfs clk tree if debugfs has been | |
116 | * initialized. Otherwise it bails out early since the debugfs clk tree | |
117 | * will be created lazily by clk_debug_init as part of a late_initcall. | |
118 | * | |
119 | * Caller must hold prepare_lock. Only clk_init calls this function (so | |
120 | * far) so this is taken care. | |
121 | */ | |
122 | static int clk_debug_register(struct clk *clk) | |
123 | { | |
124 | struct clk *parent; | |
125 | struct dentry *pdentry; | |
126 | int ret = 0; | |
127 | ||
128 | if (!inited) | |
129 | goto out; | |
130 | ||
131 | parent = clk->parent; | |
132 | ||
133 | /* | |
134 | * Check to see if a clk is a root clk. Also check that it is | |
135 | * safe to add this clk to debugfs | |
136 | */ | |
137 | if (!parent) | |
138 | if (clk->flags & CLK_IS_ROOT) | |
139 | pdentry = rootdir; | |
140 | else | |
141 | pdentry = orphandir; | |
142 | else | |
143 | if (parent->dentry) | |
144 | pdentry = parent->dentry; | |
145 | else | |
146 | goto out; | |
147 | ||
148 | ret = clk_debug_create_subtree(clk, pdentry); | |
149 | ||
150 | out: | |
151 | return ret; | |
152 | } | |
153 | ||
154 | /** | |
155 | * clk_debug_init - lazily create the debugfs clk tree visualization | |
156 | * | |
157 | * clks are often initialized very early during boot before memory can | |
158 | * be dynamically allocated and well before debugfs is setup. | |
159 | * clk_debug_init walks the clk tree hierarchy while holding | |
160 | * prepare_lock and creates the topology as part of a late_initcall, | |
161 | * thus insuring that clks initialized very early will still be | |
162 | * represented in the debugfs clk tree. This function should only be | |
163 | * called once at boot-time, and all other clks added dynamically will | |
164 | * be done so with clk_debug_register. | |
165 | */ | |
166 | static int __init clk_debug_init(void) | |
167 | { | |
168 | struct clk *clk; | |
169 | struct hlist_node *tmp; | |
170 | ||
171 | rootdir = debugfs_create_dir("clk", NULL); | |
172 | ||
173 | if (!rootdir) | |
174 | return -ENOMEM; | |
175 | ||
176 | orphandir = debugfs_create_dir("orphans", rootdir); | |
177 | ||
178 | if (!orphandir) | |
179 | return -ENOMEM; | |
180 | ||
181 | mutex_lock(&prepare_lock); | |
182 | ||
183 | hlist_for_each_entry(clk, tmp, &clk_root_list, child_node) | |
184 | clk_debug_create_subtree(clk, rootdir); | |
185 | ||
186 | hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node) | |
187 | clk_debug_create_subtree(clk, orphandir); | |
188 | ||
189 | inited = 1; | |
190 | ||
191 | mutex_unlock(&prepare_lock); | |
192 | ||
193 | return 0; | |
194 | } | |
195 | late_initcall(clk_debug_init); | |
196 | #else | |
197 | static inline int clk_debug_register(struct clk *clk) { return 0; } | |
70d347e6 | 198 | #endif |
b2476490 | 199 | |
b2476490 MT |
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); | |
b2476490 MT |
249 | |
250 | /*** helper functions ***/ | |
251 | ||
252 | inline const char *__clk_get_name(struct clk *clk) | |
253 | { | |
254 | return !clk ? NULL : clk->name; | |
255 | } | |
256 | ||
257 | inline struct clk_hw *__clk_get_hw(struct clk *clk) | |
258 | { | |
259 | return !clk ? NULL : clk->hw; | |
260 | } | |
261 | ||
262 | inline u8 __clk_get_num_parents(struct clk *clk) | |
263 | { | |
264 | return !clk ? -EINVAL : clk->num_parents; | |
265 | } | |
266 | ||
267 | inline struct clk *__clk_get_parent(struct clk *clk) | |
268 | { | |
269 | return !clk ? NULL : clk->parent; | |
270 | } | |
271 | ||
272 | inline int __clk_get_enable_count(struct clk *clk) | |
273 | { | |
274 | return !clk ? -EINVAL : clk->enable_count; | |
275 | } | |
276 | ||
277 | inline int __clk_get_prepare_count(struct clk *clk) | |
278 | { | |
279 | return !clk ? -EINVAL : clk->prepare_count; | |
280 | } | |
281 | ||
282 | unsigned long __clk_get_rate(struct clk *clk) | |
283 | { | |
284 | unsigned long ret; | |
285 | ||
286 | if (!clk) { | |
34e44fe8 | 287 | ret = 0; |
b2476490 MT |
288 | goto out; |
289 | } | |
290 | ||
291 | ret = clk->rate; | |
292 | ||
293 | if (clk->flags & CLK_IS_ROOT) | |
294 | goto out; | |
295 | ||
296 | if (!clk->parent) | |
34e44fe8 | 297 | ret = 0; |
b2476490 MT |
298 | |
299 | out: | |
300 | return ret; | |
301 | } | |
302 | ||
303 | inline unsigned long __clk_get_flags(struct clk *clk) | |
304 | { | |
305 | return !clk ? -EINVAL : clk->flags; | |
306 | } | |
307 | ||
308 | int __clk_is_enabled(struct clk *clk) | |
309 | { | |
310 | int ret; | |
311 | ||
312 | if (!clk) | |
313 | return -EINVAL; | |
314 | ||
315 | /* | |
316 | * .is_enabled is only mandatory for clocks that gate | |
317 | * fall back to software usage counter if .is_enabled is missing | |
318 | */ | |
319 | if (!clk->ops->is_enabled) { | |
320 | ret = clk->enable_count ? 1 : 0; | |
321 | goto out; | |
322 | } | |
323 | ||
324 | ret = clk->ops->is_enabled(clk->hw); | |
325 | out: | |
326 | return ret; | |
327 | } | |
328 | ||
329 | static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk) | |
330 | { | |
331 | struct clk *child; | |
332 | struct clk *ret; | |
333 | struct hlist_node *tmp; | |
334 | ||
335 | if (!strcmp(clk->name, name)) | |
336 | return clk; | |
337 | ||
338 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
339 | ret = __clk_lookup_subtree(name, child); | |
340 | if (ret) | |
341 | return ret; | |
342 | } | |
343 | ||
344 | return NULL; | |
345 | } | |
346 | ||
347 | struct clk *__clk_lookup(const char *name) | |
348 | { | |
349 | struct clk *root_clk; | |
350 | struct clk *ret; | |
351 | struct hlist_node *tmp; | |
352 | ||
353 | if (!name) | |
354 | return NULL; | |
355 | ||
356 | /* search the 'proper' clk tree first */ | |
357 | hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) { | |
358 | ret = __clk_lookup_subtree(name, root_clk); | |
359 | if (ret) | |
360 | return ret; | |
361 | } | |
362 | ||
363 | /* if not found, then search the orphan tree */ | |
364 | hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) { | |
365 | ret = __clk_lookup_subtree(name, root_clk); | |
366 | if (ret) | |
367 | return ret; | |
368 | } | |
369 | ||
370 | return NULL; | |
371 | } | |
372 | ||
373 | /*** clk api ***/ | |
374 | ||
375 | void __clk_unprepare(struct clk *clk) | |
376 | { | |
377 | if (!clk) | |
378 | return; | |
379 | ||
380 | if (WARN_ON(clk->prepare_count == 0)) | |
381 | return; | |
382 | ||
383 | if (--clk->prepare_count > 0) | |
384 | return; | |
385 | ||
386 | WARN_ON(clk->enable_count > 0); | |
387 | ||
388 | if (clk->ops->unprepare) | |
389 | clk->ops->unprepare(clk->hw); | |
390 | ||
391 | __clk_unprepare(clk->parent); | |
392 | } | |
393 | ||
394 | /** | |
395 | * clk_unprepare - undo preparation of a clock source | |
396 | * @clk: the clk being unprepare | |
397 | * | |
398 | * clk_unprepare may sleep, which differentiates it from clk_disable. In a | |
399 | * simple case, clk_unprepare can be used instead of clk_disable to gate a clk | |
400 | * if the operation may sleep. One example is a clk which is accessed over | |
401 | * I2c. In the complex case a clk gate operation may require a fast and a slow | |
402 | * part. It is this reason that clk_unprepare and clk_disable are not mutually | |
403 | * exclusive. In fact clk_disable must be called before clk_unprepare. | |
404 | */ | |
405 | void clk_unprepare(struct clk *clk) | |
406 | { | |
407 | mutex_lock(&prepare_lock); | |
408 | __clk_unprepare(clk); | |
409 | mutex_unlock(&prepare_lock); | |
410 | } | |
411 | EXPORT_SYMBOL_GPL(clk_unprepare); | |
412 | ||
413 | int __clk_prepare(struct clk *clk) | |
414 | { | |
415 | int ret = 0; | |
416 | ||
417 | if (!clk) | |
418 | return 0; | |
419 | ||
420 | if (clk->prepare_count == 0) { | |
421 | ret = __clk_prepare(clk->parent); | |
422 | if (ret) | |
423 | return ret; | |
424 | ||
425 | if (clk->ops->prepare) { | |
426 | ret = clk->ops->prepare(clk->hw); | |
427 | if (ret) { | |
428 | __clk_unprepare(clk->parent); | |
429 | return ret; | |
430 | } | |
431 | } | |
432 | } | |
433 | ||
434 | clk->prepare_count++; | |
435 | ||
436 | return 0; | |
437 | } | |
438 | ||
439 | /** | |
440 | * clk_prepare - prepare a clock source | |
441 | * @clk: the clk being prepared | |
442 | * | |
443 | * clk_prepare may sleep, which differentiates it from clk_enable. In a simple | |
444 | * case, clk_prepare can be used instead of clk_enable to ungate a clk if the | |
445 | * operation may sleep. One example is a clk which is accessed over I2c. In | |
446 | * the complex case a clk ungate operation may require a fast and a slow part. | |
447 | * It is this reason that clk_prepare and clk_enable are not mutually | |
448 | * exclusive. In fact clk_prepare must be called before clk_enable. | |
449 | * Returns 0 on success, -EERROR otherwise. | |
450 | */ | |
451 | int clk_prepare(struct clk *clk) | |
452 | { | |
453 | int ret; | |
454 | ||
455 | mutex_lock(&prepare_lock); | |
456 | ret = __clk_prepare(clk); | |
457 | mutex_unlock(&prepare_lock); | |
458 | ||
459 | return ret; | |
460 | } | |
461 | EXPORT_SYMBOL_GPL(clk_prepare); | |
462 | ||
463 | static void __clk_disable(struct clk *clk) | |
464 | { | |
465 | if (!clk) | |
466 | return; | |
467 | ||
468 | if (WARN_ON(clk->enable_count == 0)) | |
469 | return; | |
470 | ||
471 | if (--clk->enable_count > 0) | |
472 | return; | |
473 | ||
474 | if (clk->ops->disable) | |
475 | clk->ops->disable(clk->hw); | |
476 | ||
477 | __clk_disable(clk->parent); | |
478 | } | |
479 | ||
480 | /** | |
481 | * clk_disable - gate a clock | |
482 | * @clk: the clk being gated | |
483 | * | |
484 | * clk_disable must not sleep, which differentiates it from clk_unprepare. In | |
485 | * a simple case, clk_disable can be used instead of clk_unprepare to gate a | |
486 | * clk if the operation is fast and will never sleep. One example is a | |
487 | * SoC-internal clk which is controlled via simple register writes. In the | |
488 | * complex case a clk gate operation may require a fast and a slow part. It is | |
489 | * this reason that clk_unprepare and clk_disable are not mutually exclusive. | |
490 | * In fact clk_disable must be called before clk_unprepare. | |
491 | */ | |
492 | void clk_disable(struct clk *clk) | |
493 | { | |
494 | unsigned long flags; | |
495 | ||
496 | spin_lock_irqsave(&enable_lock, flags); | |
497 | __clk_disable(clk); | |
498 | spin_unlock_irqrestore(&enable_lock, flags); | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(clk_disable); | |
501 | ||
502 | static int __clk_enable(struct clk *clk) | |
503 | { | |
504 | int ret = 0; | |
505 | ||
506 | if (!clk) | |
507 | return 0; | |
508 | ||
509 | if (WARN_ON(clk->prepare_count == 0)) | |
510 | return -ESHUTDOWN; | |
511 | ||
512 | if (clk->enable_count == 0) { | |
513 | ret = __clk_enable(clk->parent); | |
514 | ||
515 | if (ret) | |
516 | return ret; | |
517 | ||
518 | if (clk->ops->enable) { | |
519 | ret = clk->ops->enable(clk->hw); | |
520 | if (ret) { | |
521 | __clk_disable(clk->parent); | |
522 | return ret; | |
523 | } | |
524 | } | |
525 | } | |
526 | ||
527 | clk->enable_count++; | |
528 | return 0; | |
529 | } | |
530 | ||
531 | /** | |
532 | * clk_enable - ungate a clock | |
533 | * @clk: the clk being ungated | |
534 | * | |
535 | * clk_enable must not sleep, which differentiates it from clk_prepare. In a | |
536 | * simple case, clk_enable can be used instead of clk_prepare to ungate a clk | |
537 | * if the operation will never sleep. One example is a SoC-internal clk which | |
538 | * is controlled via simple register writes. In the complex case a clk ungate | |
539 | * operation may require a fast and a slow part. It is this reason that | |
540 | * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare | |
541 | * must be called before clk_enable. Returns 0 on success, -EERROR | |
542 | * otherwise. | |
543 | */ | |
544 | int clk_enable(struct clk *clk) | |
545 | { | |
546 | unsigned long flags; | |
547 | int ret; | |
548 | ||
549 | spin_lock_irqsave(&enable_lock, flags); | |
550 | ret = __clk_enable(clk); | |
551 | spin_unlock_irqrestore(&enable_lock, flags); | |
552 | ||
553 | return ret; | |
554 | } | |
555 | EXPORT_SYMBOL_GPL(clk_enable); | |
556 | ||
557 | /** | |
558 | * clk_get_rate - return the rate of clk | |
559 | * @clk: the clk whose rate is being returned | |
560 | * | |
561 | * Simply returns the cached rate of the clk. Does not query the hardware. If | |
34e44fe8 | 562 | * clk is NULL then returns 0. |
b2476490 MT |
563 | */ |
564 | unsigned long clk_get_rate(struct clk *clk) | |
565 | { | |
566 | unsigned long rate; | |
567 | ||
568 | mutex_lock(&prepare_lock); | |
569 | rate = __clk_get_rate(clk); | |
570 | mutex_unlock(&prepare_lock); | |
571 | ||
572 | return rate; | |
573 | } | |
574 | EXPORT_SYMBOL_GPL(clk_get_rate); | |
575 | ||
576 | /** | |
577 | * __clk_round_rate - round the given rate for a clk | |
578 | * @clk: round the rate of this clock | |
579 | * | |
580 | * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate | |
581 | */ | |
582 | unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) | |
583 | { | |
81536e07 | 584 | unsigned long parent_rate = 0; |
b2476490 MT |
585 | |
586 | if (!clk) | |
587 | return -EINVAL; | |
588 | ||
f4d8af2e SG |
589 | if (!clk->ops->round_rate) { |
590 | if (clk->flags & CLK_SET_RATE_PARENT) | |
591 | return __clk_round_rate(clk->parent, rate); | |
592 | else | |
593 | return clk->rate; | |
594 | } | |
b2476490 | 595 | |
81536e07 SG |
596 | if (clk->parent) |
597 | parent_rate = clk->parent->rate; | |
598 | ||
599 | return clk->ops->round_rate(clk->hw, rate, &parent_rate); | |
b2476490 MT |
600 | } |
601 | ||
602 | /** | |
603 | * clk_round_rate - round the given rate for a clk | |
604 | * @clk: the clk for which we are rounding a rate | |
605 | * @rate: the rate which is to be rounded | |
606 | * | |
607 | * Takes in a rate as input and rounds it to a rate that the clk can actually | |
608 | * use which is then returned. If clk doesn't support round_rate operation | |
609 | * then the parent rate is returned. | |
610 | */ | |
611 | long clk_round_rate(struct clk *clk, unsigned long rate) | |
612 | { | |
613 | unsigned long ret; | |
614 | ||
615 | mutex_lock(&prepare_lock); | |
616 | ret = __clk_round_rate(clk, rate); | |
617 | mutex_unlock(&prepare_lock); | |
618 | ||
619 | return ret; | |
620 | } | |
621 | EXPORT_SYMBOL_GPL(clk_round_rate); | |
622 | ||
623 | /** | |
624 | * __clk_notify - call clk notifier chain | |
625 | * @clk: struct clk * that is changing rate | |
626 | * @msg: clk notifier type (see include/linux/clk.h) | |
627 | * @old_rate: old clk rate | |
628 | * @new_rate: new clk rate | |
629 | * | |
630 | * Triggers a notifier call chain on the clk rate-change notification | |
631 | * for 'clk'. Passes a pointer to the struct clk and the previous | |
632 | * and current rates to the notifier callback. Intended to be called by | |
633 | * internal clock code only. Returns NOTIFY_DONE from the last driver | |
634 | * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if | |
635 | * a driver returns that. | |
636 | */ | |
637 | static int __clk_notify(struct clk *clk, unsigned long msg, | |
638 | unsigned long old_rate, unsigned long new_rate) | |
639 | { | |
640 | struct clk_notifier *cn; | |
641 | struct clk_notifier_data cnd; | |
642 | int ret = NOTIFY_DONE; | |
643 | ||
644 | cnd.clk = clk; | |
645 | cnd.old_rate = old_rate; | |
646 | cnd.new_rate = new_rate; | |
647 | ||
648 | list_for_each_entry(cn, &clk_notifier_list, node) { | |
649 | if (cn->clk == clk) { | |
650 | ret = srcu_notifier_call_chain(&cn->notifier_head, msg, | |
651 | &cnd); | |
652 | break; | |
653 | } | |
654 | } | |
655 | ||
656 | return ret; | |
657 | } | |
658 | ||
659 | /** | |
660 | * __clk_recalc_rates | |
661 | * @clk: first clk in the subtree | |
662 | * @msg: notification type (see include/linux/clk.h) | |
663 | * | |
664 | * Walks the subtree of clks starting with clk and recalculates rates as it | |
665 | * goes. Note that if a clk does not implement the .recalc_rate callback then | |
666 | * it is assumed that the clock will take on the rate of it's parent. | |
667 | * | |
668 | * clk_recalc_rates also propagates the POST_RATE_CHANGE notification, | |
669 | * if necessary. | |
670 | * | |
671 | * Caller must hold prepare_lock. | |
672 | */ | |
673 | static void __clk_recalc_rates(struct clk *clk, unsigned long msg) | |
674 | { | |
675 | unsigned long old_rate; | |
676 | unsigned long parent_rate = 0; | |
677 | struct hlist_node *tmp; | |
678 | struct clk *child; | |
679 | ||
680 | old_rate = clk->rate; | |
681 | ||
682 | if (clk->parent) | |
683 | parent_rate = clk->parent->rate; | |
684 | ||
685 | if (clk->ops->recalc_rate) | |
686 | clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate); | |
687 | else | |
688 | clk->rate = parent_rate; | |
689 | ||
690 | /* | |
691 | * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE | |
692 | * & ABORT_RATE_CHANGE notifiers | |
693 | */ | |
694 | if (clk->notifier_count && msg) | |
695 | __clk_notify(clk, msg, old_rate, clk->rate); | |
696 | ||
697 | hlist_for_each_entry(child, tmp, &clk->children, child_node) | |
698 | __clk_recalc_rates(child, msg); | |
699 | } | |
700 | ||
701 | /** | |
702 | * __clk_speculate_rates | |
703 | * @clk: first clk in the subtree | |
704 | * @parent_rate: the "future" rate of clk's parent | |
705 | * | |
706 | * Walks the subtree of clks starting with clk, speculating rates as it | |
707 | * goes and firing off PRE_RATE_CHANGE notifications as necessary. | |
708 | * | |
709 | * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending | |
710 | * pre-rate change notifications and returns early if no clks in the | |
711 | * subtree have subscribed to the notifications. Note that if a clk does not | |
712 | * implement the .recalc_rate callback then it is assumed that the clock will | |
713 | * take on the rate of it's parent. | |
714 | * | |
715 | * Caller must hold prepare_lock. | |
716 | */ | |
717 | static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate) | |
718 | { | |
719 | struct hlist_node *tmp; | |
720 | struct clk *child; | |
721 | unsigned long new_rate; | |
722 | int ret = NOTIFY_DONE; | |
723 | ||
724 | if (clk->ops->recalc_rate) | |
725 | new_rate = clk->ops->recalc_rate(clk->hw, parent_rate); | |
726 | else | |
727 | new_rate = parent_rate; | |
728 | ||
729 | /* abort the rate change if a driver returns NOTIFY_BAD */ | |
730 | if (clk->notifier_count) | |
731 | ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate); | |
732 | ||
733 | if (ret == NOTIFY_BAD) | |
734 | goto out; | |
735 | ||
736 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
737 | ret = __clk_speculate_rates(child, new_rate); | |
738 | if (ret == NOTIFY_BAD) | |
739 | break; | |
740 | } | |
741 | ||
742 | out: | |
743 | return ret; | |
744 | } | |
745 | ||
746 | static void clk_calc_subtree(struct clk *clk, unsigned long new_rate) | |
747 | { | |
748 | struct clk *child; | |
749 | struct hlist_node *tmp; | |
750 | ||
751 | clk->new_rate = new_rate; | |
752 | ||
753 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
754 | if (child->ops->recalc_rate) | |
755 | child->new_rate = child->ops->recalc_rate(child->hw, new_rate); | |
756 | else | |
757 | child->new_rate = new_rate; | |
758 | clk_calc_subtree(child, child->new_rate); | |
759 | } | |
760 | } | |
761 | ||
762 | /* | |
763 | * calculate the new rates returning the topmost clock that has to be | |
764 | * changed. | |
765 | */ | |
766 | static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) | |
767 | { | |
768 | struct clk *top = clk; | |
81536e07 | 769 | unsigned long best_parent_rate = 0; |
b2476490 MT |
770 | unsigned long new_rate; |
771 | ||
7452b219 MT |
772 | /* sanity */ |
773 | if (IS_ERR_OR_NULL(clk)) | |
774 | return NULL; | |
775 | ||
63f5c3b2 MT |
776 | /* save parent rate, if it exists */ |
777 | if (clk->parent) | |
778 | best_parent_rate = clk->parent->rate; | |
779 | ||
7452b219 MT |
780 | /* never propagate up to the parent */ |
781 | if (!(clk->flags & CLK_SET_RATE_PARENT)) { | |
782 | if (!clk->ops->round_rate) { | |
783 | clk->new_rate = clk->rate; | |
784 | return NULL; | |
7452b219 | 785 | } |
63f5c3b2 MT |
786 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
787 | goto out; | |
7452b219 MT |
788 | } |
789 | ||
790 | /* need clk->parent from here on out */ | |
791 | if (!clk->parent) { | |
792 | pr_debug("%s: %s has NULL parent\n", __func__, clk->name); | |
b2476490 MT |
793 | return NULL; |
794 | } | |
795 | ||
7452b219 | 796 | if (!clk->ops->round_rate) { |
b2476490 | 797 | top = clk_calc_new_rates(clk->parent, rate); |
1b2f9903 | 798 | new_rate = clk->parent->new_rate; |
b2476490 MT |
799 | |
800 | goto out; | |
801 | } | |
802 | ||
7452b219 | 803 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
b2476490 MT |
804 | |
805 | if (best_parent_rate != clk->parent->rate) { | |
806 | top = clk_calc_new_rates(clk->parent, best_parent_rate); | |
807 | ||
808 | goto out; | |
809 | } | |
810 | ||
811 | out: | |
812 | clk_calc_subtree(clk, new_rate); | |
813 | ||
814 | return top; | |
815 | } | |
816 | ||
817 | /* | |
818 | * Notify about rate changes in a subtree. Always walk down the whole tree | |
819 | * so that in case of an error we can walk down the whole tree again and | |
820 | * abort the change. | |
821 | */ | |
822 | static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) | |
823 | { | |
824 | struct hlist_node *tmp; | |
825 | struct clk *child, *fail_clk = NULL; | |
826 | int ret = NOTIFY_DONE; | |
827 | ||
828 | if (clk->rate == clk->new_rate) | |
829 | return 0; | |
830 | ||
831 | if (clk->notifier_count) { | |
832 | ret = __clk_notify(clk, event, clk->rate, clk->new_rate); | |
833 | if (ret == NOTIFY_BAD) | |
834 | fail_clk = clk; | |
835 | } | |
836 | ||
837 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { | |
838 | clk = clk_propagate_rate_change(child, event); | |
839 | if (clk) | |
840 | fail_clk = clk; | |
841 | } | |
842 | ||
843 | return fail_clk; | |
844 | } | |
845 | ||
846 | /* | |
847 | * walk down a subtree and set the new rates notifying the rate | |
848 | * change on the way | |
849 | */ | |
850 | static void clk_change_rate(struct clk *clk) | |
851 | { | |
852 | struct clk *child; | |
853 | unsigned long old_rate; | |
bf47b4fd | 854 | unsigned long best_parent_rate = 0; |
b2476490 MT |
855 | struct hlist_node *tmp; |
856 | ||
857 | old_rate = clk->rate; | |
858 | ||
bf47b4fd PM |
859 | if (clk->parent) |
860 | best_parent_rate = clk->parent->rate; | |
861 | ||
b2476490 | 862 | if (clk->ops->set_rate) |
bf47b4fd | 863 | clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate); |
b2476490 MT |
864 | |
865 | if (clk->ops->recalc_rate) | |
bf47b4fd | 866 | clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate); |
b2476490 | 867 | else |
bf47b4fd | 868 | clk->rate = best_parent_rate; |
b2476490 MT |
869 | |
870 | if (clk->notifier_count && old_rate != clk->rate) | |
871 | __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); | |
872 | ||
873 | hlist_for_each_entry(child, tmp, &clk->children, child_node) | |
874 | clk_change_rate(child); | |
875 | } | |
876 | ||
877 | /** | |
878 | * clk_set_rate - specify a new rate for clk | |
879 | * @clk: the clk whose rate is being changed | |
880 | * @rate: the new rate for clk | |
881 | * | |
5654dc94 | 882 | * In the simplest case clk_set_rate will only adjust the rate of clk. |
b2476490 | 883 | * |
5654dc94 MT |
884 | * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to |
885 | * propagate up to clk's parent; whether or not this happens depends on the | |
886 | * outcome of clk's .round_rate implementation. If *parent_rate is unchanged | |
887 | * after calling .round_rate then upstream parent propagation is ignored. If | |
888 | * *parent_rate comes back with a new rate for clk's parent then we propagate | |
889 | * up to clk's parent and set it's rate. Upward propagation will continue | |
890 | * until either a clk does not support the CLK_SET_RATE_PARENT flag or | |
891 | * .round_rate stops requesting changes to clk's parent_rate. | |
b2476490 | 892 | * |
5654dc94 MT |
893 | * Rate changes are accomplished via tree traversal that also recalculates the |
894 | * rates for the clocks and fires off POST_RATE_CHANGE notifiers. | |
b2476490 MT |
895 | * |
896 | * Returns 0 on success, -EERROR otherwise. | |
897 | */ | |
898 | int clk_set_rate(struct clk *clk, unsigned long rate) | |
899 | { | |
900 | struct clk *top, *fail_clk; | |
901 | int ret = 0; | |
902 | ||
903 | /* prevent racing with updates to the clock topology */ | |
904 | mutex_lock(&prepare_lock); | |
905 | ||
906 | /* bail early if nothing to do */ | |
907 | if (rate == clk->rate) | |
908 | goto out; | |
909 | ||
7e0fa1b5 | 910 | if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) { |
0e1c0301 VK |
911 | ret = -EBUSY; |
912 | goto out; | |
913 | } | |
914 | ||
b2476490 MT |
915 | /* calculate new rates and get the topmost changed clock */ |
916 | top = clk_calc_new_rates(clk, rate); | |
917 | if (!top) { | |
918 | ret = -EINVAL; | |
919 | goto out; | |
920 | } | |
921 | ||
922 | /* notify that we are about to change rates */ | |
923 | fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); | |
924 | if (fail_clk) { | |
925 | pr_warn("%s: failed to set %s rate\n", __func__, | |
926 | fail_clk->name); | |
927 | clk_propagate_rate_change(top, ABORT_RATE_CHANGE); | |
928 | ret = -EBUSY; | |
929 | goto out; | |
930 | } | |
931 | ||
932 | /* change the rates */ | |
933 | clk_change_rate(top); | |
934 | ||
935 | mutex_unlock(&prepare_lock); | |
936 | ||
937 | return 0; | |
938 | out: | |
939 | mutex_unlock(&prepare_lock); | |
940 | ||
941 | return ret; | |
942 | } | |
943 | EXPORT_SYMBOL_GPL(clk_set_rate); | |
944 | ||
945 | /** | |
946 | * clk_get_parent - return the parent of a clk | |
947 | * @clk: the clk whose parent gets returned | |
948 | * | |
949 | * Simply returns clk->parent. Returns NULL if clk is NULL. | |
950 | */ | |
951 | struct clk *clk_get_parent(struct clk *clk) | |
952 | { | |
953 | struct clk *parent; | |
954 | ||
955 | mutex_lock(&prepare_lock); | |
956 | parent = __clk_get_parent(clk); | |
957 | mutex_unlock(&prepare_lock); | |
958 | ||
959 | return parent; | |
960 | } | |
961 | EXPORT_SYMBOL_GPL(clk_get_parent); | |
962 | ||
963 | /* | |
964 | * .get_parent is mandatory for clocks with multiple possible parents. It is | |
965 | * optional for single-parent clocks. Always call .get_parent if it is | |
966 | * available and WARN if it is missing for multi-parent clocks. | |
967 | * | |
968 | * For single-parent clocks without .get_parent, first check to see if the | |
969 | * .parents array exists, and if so use it to avoid an expensive tree | |
970 | * traversal. If .parents does not exist then walk the tree with __clk_lookup. | |
971 | */ | |
972 | static struct clk *__clk_init_parent(struct clk *clk) | |
973 | { | |
974 | struct clk *ret = NULL; | |
975 | u8 index; | |
976 | ||
977 | /* handle the trivial cases */ | |
978 | ||
979 | if (!clk->num_parents) | |
980 | goto out; | |
981 | ||
982 | if (clk->num_parents == 1) { | |
983 | if (IS_ERR_OR_NULL(clk->parent)) | |
984 | ret = clk->parent = __clk_lookup(clk->parent_names[0]); | |
985 | ret = clk->parent; | |
986 | goto out; | |
987 | } | |
988 | ||
989 | if (!clk->ops->get_parent) { | |
990 | WARN(!clk->ops->get_parent, | |
991 | "%s: multi-parent clocks must implement .get_parent\n", | |
992 | __func__); | |
993 | goto out; | |
994 | }; | |
995 | ||
996 | /* | |
997 | * Do our best to cache parent clocks in clk->parents. This prevents | |
998 | * unnecessary and expensive calls to __clk_lookup. We don't set | |
999 | * clk->parent here; that is done by the calling function | |
1000 | */ | |
1001 | ||
1002 | index = clk->ops->get_parent(clk->hw); | |
1003 | ||
1004 | if (!clk->parents) | |
1005 | clk->parents = | |
7975059d | 1006 | kzalloc((sizeof(struct clk*) * clk->num_parents), |
b2476490 MT |
1007 | GFP_KERNEL); |
1008 | ||
1009 | if (!clk->parents) | |
1010 | ret = __clk_lookup(clk->parent_names[index]); | |
1011 | else if (!clk->parents[index]) | |
1012 | ret = clk->parents[index] = | |
1013 | __clk_lookup(clk->parent_names[index]); | |
1014 | else | |
1015 | ret = clk->parents[index]; | |
1016 | ||
1017 | out: | |
1018 | return ret; | |
1019 | } | |
1020 | ||
1021 | void __clk_reparent(struct clk *clk, struct clk *new_parent) | |
1022 | { | |
1023 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
1024 | struct dentry *d; | |
1025 | struct dentry *new_parent_d; | |
1026 | #endif | |
1027 | ||
1028 | if (!clk || !new_parent) | |
1029 | return; | |
1030 | ||
1031 | hlist_del(&clk->child_node); | |
1032 | ||
1033 | if (new_parent) | |
1034 | hlist_add_head(&clk->child_node, &new_parent->children); | |
1035 | else | |
1036 | hlist_add_head(&clk->child_node, &clk_orphan_list); | |
1037 | ||
1038 | #ifdef CONFIG_COMMON_CLK_DEBUG | |
1039 | if (!inited) | |
1040 | goto out; | |
1041 | ||
1042 | if (new_parent) | |
1043 | new_parent_d = new_parent->dentry; | |
1044 | else | |
1045 | new_parent_d = orphandir; | |
1046 | ||
1047 | d = debugfs_rename(clk->dentry->d_parent, clk->dentry, | |
1048 | new_parent_d, clk->name); | |
1049 | if (d) | |
1050 | clk->dentry = d; | |
1051 | else | |
1052 | pr_debug("%s: failed to rename debugfs entry for %s\n", | |
1053 | __func__, clk->name); | |
1054 | out: | |
1055 | #endif | |
1056 | ||
1057 | clk->parent = new_parent; | |
1058 | ||
1059 | __clk_recalc_rates(clk, POST_RATE_CHANGE); | |
1060 | } | |
1061 | ||
1062 | static int __clk_set_parent(struct clk *clk, struct clk *parent) | |
1063 | { | |
1064 | struct clk *old_parent; | |
1065 | unsigned long flags; | |
1066 | int ret = -EINVAL; | |
1067 | u8 i; | |
1068 | ||
1069 | old_parent = clk->parent; | |
1070 | ||
863b1327 | 1071 | if (!clk->parents) |
7975059d RN |
1072 | clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), |
1073 | GFP_KERNEL); | |
b2476490 MT |
1074 | |
1075 | /* | |
863b1327 RN |
1076 | * find index of new parent clock using cached parent ptrs, |
1077 | * or if not yet cached, use string name comparison and cache | |
1078 | * them now to avoid future calls to __clk_lookup. | |
b2476490 | 1079 | */ |
863b1327 RN |
1080 | for (i = 0; i < clk->num_parents; i++) { |
1081 | if (clk->parents && clk->parents[i] == parent) | |
1082 | break; | |
1083 | else if (!strcmp(clk->parent_names[i], parent->name)) { | |
1084 | if (clk->parents) | |
1085 | clk->parents[i] = __clk_lookup(parent->name); | |
1086 | break; | |
1087 | } | |
1088 | } | |
b2476490 MT |
1089 | |
1090 | if (i == clk->num_parents) { | |
1091 | pr_debug("%s: clock %s is not a possible parent of clock %s\n", | |
1092 | __func__, parent->name, clk->name); | |
1093 | goto out; | |
1094 | } | |
1095 | ||
1096 | /* migrate prepare and enable */ | |
1097 | if (clk->prepare_count) | |
1098 | __clk_prepare(parent); | |
1099 | ||
1100 | /* FIXME replace with clk_is_enabled(clk) someday */ | |
1101 | spin_lock_irqsave(&enable_lock, flags); | |
1102 | if (clk->enable_count) | |
1103 | __clk_enable(parent); | |
1104 | spin_unlock_irqrestore(&enable_lock, flags); | |
1105 | ||
1106 | /* change clock input source */ | |
1107 | ret = clk->ops->set_parent(clk->hw, i); | |
1108 | ||
1109 | /* clean up old prepare and enable */ | |
1110 | spin_lock_irqsave(&enable_lock, flags); | |
1111 | if (clk->enable_count) | |
1112 | __clk_disable(old_parent); | |
1113 | spin_unlock_irqrestore(&enable_lock, flags); | |
1114 | ||
1115 | if (clk->prepare_count) | |
1116 | __clk_unprepare(old_parent); | |
1117 | ||
1118 | out: | |
1119 | return ret; | |
1120 | } | |
1121 | ||
1122 | /** | |
1123 | * clk_set_parent - switch the parent of a mux clk | |
1124 | * @clk: the mux clk whose input we are switching | |
1125 | * @parent: the new input to clk | |
1126 | * | |
1127 | * Re-parent clk to use parent as it's new input source. If clk has the | |
1128 | * CLK_SET_PARENT_GATE flag set then clk must be gated for this | |
1129 | * operation to succeed. After successfully changing clk's parent | |
1130 | * clk_set_parent will update the clk topology, sysfs topology and | |
1131 | * propagate rate recalculation via __clk_recalc_rates. Returns 0 on | |
1132 | * success, -EERROR otherwise. | |
1133 | */ | |
1134 | int clk_set_parent(struct clk *clk, struct clk *parent) | |
1135 | { | |
1136 | int ret = 0; | |
1137 | ||
1138 | if (!clk || !clk->ops) | |
1139 | return -EINVAL; | |
1140 | ||
1141 | if (!clk->ops->set_parent) | |
1142 | return -ENOSYS; | |
1143 | ||
1144 | /* prevent racing with updates to the clock topology */ | |
1145 | mutex_lock(&prepare_lock); | |
1146 | ||
1147 | if (clk->parent == parent) | |
1148 | goto out; | |
1149 | ||
1150 | /* propagate PRE_RATE_CHANGE notifications */ | |
1151 | if (clk->notifier_count) | |
1152 | ret = __clk_speculate_rates(clk, parent->rate); | |
1153 | ||
1154 | /* abort if a driver objects */ | |
1155 | if (ret == NOTIFY_STOP) | |
1156 | goto out; | |
1157 | ||
1158 | /* only re-parent if the clock is not in use */ | |
1159 | if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) | |
1160 | ret = -EBUSY; | |
1161 | else | |
1162 | ret = __clk_set_parent(clk, parent); | |
1163 | ||
1164 | /* propagate ABORT_RATE_CHANGE if .set_parent failed */ | |
1165 | if (ret) { | |
1166 | __clk_recalc_rates(clk, ABORT_RATE_CHANGE); | |
1167 | goto out; | |
1168 | } | |
1169 | ||
1170 | /* propagate rate recalculation downstream */ | |
1171 | __clk_reparent(clk, parent); | |
1172 | ||
1173 | out: | |
1174 | mutex_unlock(&prepare_lock); | |
1175 | ||
1176 | return ret; | |
1177 | } | |
1178 | EXPORT_SYMBOL_GPL(clk_set_parent); | |
1179 | ||
1180 | /** | |
1181 | * __clk_init - initialize the data structures in a struct clk | |
1182 | * @dev: device initializing this clk, placeholder for now | |
1183 | * @clk: clk being initialized | |
1184 | * | |
1185 | * Initializes the lists in struct clk, queries the hardware for the | |
1186 | * parent and rate and sets them both. | |
b2476490 | 1187 | */ |
d1302a36 | 1188 | int __clk_init(struct device *dev, struct clk *clk) |
b2476490 | 1189 | { |
d1302a36 | 1190 | int i, ret = 0; |
b2476490 MT |
1191 | struct clk *orphan; |
1192 | struct hlist_node *tmp, *tmp2; | |
1193 | ||
1194 | if (!clk) | |
d1302a36 | 1195 | return -EINVAL; |
b2476490 MT |
1196 | |
1197 | mutex_lock(&prepare_lock); | |
1198 | ||
1199 | /* check to see if a clock with this name is already registered */ | |
d1302a36 MT |
1200 | if (__clk_lookup(clk->name)) { |
1201 | pr_debug("%s: clk %s already initialized\n", | |
1202 | __func__, clk->name); | |
1203 | ret = -EEXIST; | |
b2476490 | 1204 | goto out; |
d1302a36 | 1205 | } |
b2476490 | 1206 | |
d4d7e3dd MT |
1207 | /* check that clk_ops are sane. See Documentation/clk.txt */ |
1208 | if (clk->ops->set_rate && | |
1209 | !(clk->ops->round_rate && clk->ops->recalc_rate)) { | |
1210 | pr_warning("%s: %s must implement .round_rate & .recalc_rate\n", | |
1211 | __func__, clk->name); | |
d1302a36 | 1212 | ret = -EINVAL; |
d4d7e3dd MT |
1213 | goto out; |
1214 | } | |
1215 | ||
1216 | if (clk->ops->set_parent && !clk->ops->get_parent) { | |
1217 | pr_warning("%s: %s must implement .get_parent & .set_parent\n", | |
1218 | __func__, clk->name); | |
d1302a36 | 1219 | ret = -EINVAL; |
d4d7e3dd MT |
1220 | goto out; |
1221 | } | |
1222 | ||
b2476490 MT |
1223 | /* throw a WARN if any entries in parent_names are NULL */ |
1224 | for (i = 0; i < clk->num_parents; i++) | |
1225 | WARN(!clk->parent_names[i], | |
1226 | "%s: invalid NULL in %s's .parent_names\n", | |
1227 | __func__, clk->name); | |
1228 | ||
1229 | /* | |
1230 | * Allocate an array of struct clk *'s to avoid unnecessary string | |
1231 | * look-ups of clk's possible parents. This can fail for clocks passed | |
1232 | * in to clk_init during early boot; thus any access to clk->parents[] | |
1233 | * must always check for a NULL pointer and try to populate it if | |
1234 | * necessary. | |
1235 | * | |
1236 | * If clk->parents is not NULL we skip this entire block. This allows | |
1237 | * for clock drivers to statically initialize clk->parents. | |
1238 | */ | |
9ca1c5a4 RN |
1239 | if (clk->num_parents > 1 && !clk->parents) { |
1240 | clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), | |
b2476490 MT |
1241 | GFP_KERNEL); |
1242 | /* | |
1243 | * __clk_lookup returns NULL for parents that have not been | |
1244 | * clk_init'd; thus any access to clk->parents[] must check | |
1245 | * for a NULL pointer. We can always perform lazy lookups for | |
1246 | * missing parents later on. | |
1247 | */ | |
1248 | if (clk->parents) | |
1249 | for (i = 0; i < clk->num_parents; i++) | |
1250 | clk->parents[i] = | |
1251 | __clk_lookup(clk->parent_names[i]); | |
1252 | } | |
1253 | ||
1254 | clk->parent = __clk_init_parent(clk); | |
1255 | ||
1256 | /* | |
1257 | * Populate clk->parent if parent has already been __clk_init'd. If | |
1258 | * parent has not yet been __clk_init'd then place clk in the orphan | |
1259 | * list. If clk has set the CLK_IS_ROOT flag then place it in the root | |
1260 | * clk list. | |
1261 | * | |
1262 | * Every time a new clk is clk_init'd then we walk the list of orphan | |
1263 | * clocks and re-parent any that are children of the clock currently | |
1264 | * being clk_init'd. | |
1265 | */ | |
1266 | if (clk->parent) | |
1267 | hlist_add_head(&clk->child_node, | |
1268 | &clk->parent->children); | |
1269 | else if (clk->flags & CLK_IS_ROOT) | |
1270 | hlist_add_head(&clk->child_node, &clk_root_list); | |
1271 | else | |
1272 | hlist_add_head(&clk->child_node, &clk_orphan_list); | |
1273 | ||
1274 | /* | |
1275 | * Set clk's rate. The preferred method is to use .recalc_rate. For | |
1276 | * simple clocks and lazy developers the default fallback is to use the | |
1277 | * parent's rate. If a clock doesn't have a parent (or is orphaned) | |
1278 | * then rate is set to zero. | |
1279 | */ | |
1280 | if (clk->ops->recalc_rate) | |
1281 | clk->rate = clk->ops->recalc_rate(clk->hw, | |
1282 | __clk_get_rate(clk->parent)); | |
1283 | else if (clk->parent) | |
1284 | clk->rate = clk->parent->rate; | |
1285 | else | |
1286 | clk->rate = 0; | |
1287 | ||
1288 | /* | |
1289 | * walk the list of orphan clocks and reparent any that are children of | |
1290 | * this clock | |
1291 | */ | |
1292 | hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) | |
1293 | for (i = 0; i < orphan->num_parents; i++) | |
1294 | if (!strcmp(clk->name, orphan->parent_names[i])) { | |
1295 | __clk_reparent(orphan, clk); | |
1296 | break; | |
1297 | } | |
1298 | ||
1299 | /* | |
1300 | * optional platform-specific magic | |
1301 | * | |
1302 | * The .init callback is not used by any of the basic clock types, but | |
1303 | * exists for weird hardware that must perform initialization magic. | |
1304 | * Please consider other ways of solving initialization problems before | |
1305 | * using this callback, as it's use is discouraged. | |
1306 | */ | |
1307 | if (clk->ops->init) | |
1308 | clk->ops->init(clk->hw); | |
1309 | ||
1310 | clk_debug_register(clk); | |
1311 | ||
1312 | out: | |
1313 | mutex_unlock(&prepare_lock); | |
1314 | ||
d1302a36 | 1315 | return ret; |
b2476490 MT |
1316 | } |
1317 | ||
0197b3ea SK |
1318 | /** |
1319 | * __clk_register - register a clock and return a cookie. | |
1320 | * | |
1321 | * Same as clk_register, except that the .clk field inside hw shall point to a | |
1322 | * preallocated (generally statically allocated) struct clk. None of the fields | |
1323 | * of the struct clk need to be initialized. | |
1324 | * | |
1325 | * The data pointed to by .init and .clk field shall NOT be marked as init | |
1326 | * data. | |
1327 | * | |
1328 | * __clk_register is only exposed via clk-private.h and is intended for use with | |
1329 | * very large numbers of clocks that need to be statically initialized. It is | |
1330 | * a layering violation to include clk-private.h from any code which implements | |
1331 | * a clock's .ops; as such any statically initialized clock data MUST be in a | |
1332 | * separate C file from the logic that implements it's operations. Returns 0 | |
1333 | * on success, otherwise an error code. | |
1334 | */ | |
1335 | struct clk *__clk_register(struct device *dev, struct clk_hw *hw) | |
1336 | { | |
1337 | int ret; | |
1338 | struct clk *clk; | |
1339 | ||
1340 | clk = hw->clk; | |
1341 | clk->name = hw->init->name; | |
1342 | clk->ops = hw->init->ops; | |
1343 | clk->hw = hw; | |
1344 | clk->flags = hw->init->flags; | |
1345 | clk->parent_names = hw->init->parent_names; | |
1346 | clk->num_parents = hw->init->num_parents; | |
1347 | ||
1348 | ret = __clk_init(dev, clk); | |
1349 | if (ret) | |
1350 | return ERR_PTR(ret); | |
1351 | ||
1352 | return clk; | |
1353 | } | |
1354 | EXPORT_SYMBOL_GPL(__clk_register); | |
1355 | ||
b2476490 MT |
1356 | /** |
1357 | * clk_register - allocate a new clock, register it and return an opaque cookie | |
1358 | * @dev: device that is registering this clock | |
b2476490 | 1359 | * @hw: link to hardware-specific clock data |
b2476490 MT |
1360 | * |
1361 | * clk_register is the primary interface for populating the clock tree with new | |
1362 | * clock nodes. It returns a pointer to the newly allocated struct clk which | |
1363 | * cannot be dereferenced by driver code but may be used in conjuction with the | |
d1302a36 MT |
1364 | * rest of the clock API. In the event of an error clk_register will return an |
1365 | * error code; drivers must test for an error code after calling clk_register. | |
b2476490 | 1366 | */ |
0197b3ea | 1367 | struct clk *clk_register(struct device *dev, struct clk_hw *hw) |
b2476490 | 1368 | { |
d1302a36 | 1369 | int i, ret; |
b2476490 MT |
1370 | struct clk *clk; |
1371 | ||
1372 | clk = kzalloc(sizeof(*clk), GFP_KERNEL); | |
d1302a36 MT |
1373 | if (!clk) { |
1374 | pr_err("%s: could not allocate clk\n", __func__); | |
1375 | ret = -ENOMEM; | |
1376 | goto fail_out; | |
1377 | } | |
b2476490 | 1378 | |
0197b3ea SK |
1379 | clk->name = kstrdup(hw->init->name, GFP_KERNEL); |
1380 | if (!clk->name) { | |
1381 | pr_err("%s: could not allocate clk->name\n", __func__); | |
1382 | ret = -ENOMEM; | |
1383 | goto fail_name; | |
1384 | } | |
1385 | clk->ops = hw->init->ops; | |
b2476490 | 1386 | clk->hw = hw; |
0197b3ea SK |
1387 | clk->flags = hw->init->flags; |
1388 | clk->num_parents = hw->init->num_parents; | |
b2476490 MT |
1389 | hw->clk = clk; |
1390 | ||
d1302a36 | 1391 | /* allocate local copy in case parent_names is __initdata */ |
0197b3ea | 1392 | clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents), |
d1302a36 MT |
1393 | GFP_KERNEL); |
1394 | ||
1395 | if (!clk->parent_names) { | |
1396 | pr_err("%s: could not allocate clk->parent_names\n", __func__); | |
1397 | ret = -ENOMEM; | |
1398 | goto fail_parent_names; | |
1399 | } | |
1400 | ||
1401 | ||
1402 | /* copy each string name in case parent_names is __initdata */ | |
0197b3ea SK |
1403 | for (i = 0; i < clk->num_parents; i++) { |
1404 | clk->parent_names[i] = kstrdup(hw->init->parent_names[i], | |
1405 | GFP_KERNEL); | |
d1302a36 MT |
1406 | if (!clk->parent_names[i]) { |
1407 | pr_err("%s: could not copy parent_names\n", __func__); | |
1408 | ret = -ENOMEM; | |
1409 | goto fail_parent_names_copy; | |
1410 | } | |
1411 | } | |
1412 | ||
1413 | ret = __clk_init(dev, clk); | |
1414 | if (!ret) | |
1415 | return clk; | |
b2476490 | 1416 | |
d1302a36 MT |
1417 | fail_parent_names_copy: |
1418 | while (--i >= 0) | |
1419 | kfree(clk->parent_names[i]); | |
1420 | kfree(clk->parent_names); | |
1421 | fail_parent_names: | |
0197b3ea SK |
1422 | kfree(clk->name); |
1423 | fail_name: | |
d1302a36 MT |
1424 | kfree(clk); |
1425 | fail_out: | |
1426 | return ERR_PTR(ret); | |
b2476490 MT |
1427 | } |
1428 | EXPORT_SYMBOL_GPL(clk_register); | |
1429 | ||
1df5c939 MB |
1430 | /** |
1431 | * clk_unregister - unregister a currently registered clock | |
1432 | * @clk: clock to unregister | |
1433 | * | |
1434 | * Currently unimplemented. | |
1435 | */ | |
1436 | void clk_unregister(struct clk *clk) {} | |
1437 | EXPORT_SYMBOL_GPL(clk_unregister); | |
1438 | ||
b2476490 MT |
1439 | /*** clk rate change notifiers ***/ |
1440 | ||
1441 | /** | |
1442 | * clk_notifier_register - add a clk rate change notifier | |
1443 | * @clk: struct clk * to watch | |
1444 | * @nb: struct notifier_block * with callback info | |
1445 | * | |
1446 | * Request notification when clk's rate changes. This uses an SRCU | |
1447 | * notifier because we want it to block and notifier unregistrations are | |
1448 | * uncommon. The callbacks associated with the notifier must not | |
1449 | * re-enter into the clk framework by calling any top-level clk APIs; | |
1450 | * this will cause a nested prepare_lock mutex. | |
1451 | * | |
1452 | * Pre-change notifier callbacks will be passed the current, pre-change | |
1453 | * rate of the clk via struct clk_notifier_data.old_rate. The new, | |
1454 | * post-change rate of the clk is passed via struct | |
1455 | * clk_notifier_data.new_rate. | |
1456 | * | |
1457 | * Post-change notifiers will pass the now-current, post-change rate of | |
1458 | * the clk in both struct clk_notifier_data.old_rate and struct | |
1459 | * clk_notifier_data.new_rate. | |
1460 | * | |
1461 | * Abort-change notifiers are effectively the opposite of pre-change | |
1462 | * notifiers: the original pre-change clk rate is passed in via struct | |
1463 | * clk_notifier_data.new_rate and the failed post-change rate is passed | |
1464 | * in via struct clk_notifier_data.old_rate. | |
1465 | * | |
1466 | * clk_notifier_register() must be called from non-atomic context. | |
1467 | * Returns -EINVAL if called with null arguments, -ENOMEM upon | |
1468 | * allocation failure; otherwise, passes along the return value of | |
1469 | * srcu_notifier_chain_register(). | |
1470 | */ | |
1471 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb) | |
1472 | { | |
1473 | struct clk_notifier *cn; | |
1474 | int ret = -ENOMEM; | |
1475 | ||
1476 | if (!clk || !nb) | |
1477 | return -EINVAL; | |
1478 | ||
1479 | mutex_lock(&prepare_lock); | |
1480 | ||
1481 | /* search the list of notifiers for this clk */ | |
1482 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1483 | if (cn->clk == clk) | |
1484 | break; | |
1485 | ||
1486 | /* if clk wasn't in the notifier list, allocate new clk_notifier */ | |
1487 | if (cn->clk != clk) { | |
1488 | cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); | |
1489 | if (!cn) | |
1490 | goto out; | |
1491 | ||
1492 | cn->clk = clk; | |
1493 | srcu_init_notifier_head(&cn->notifier_head); | |
1494 | ||
1495 | list_add(&cn->node, &clk_notifier_list); | |
1496 | } | |
1497 | ||
1498 | ret = srcu_notifier_chain_register(&cn->notifier_head, nb); | |
1499 | ||
1500 | clk->notifier_count++; | |
1501 | ||
1502 | out: | |
1503 | mutex_unlock(&prepare_lock); | |
1504 | ||
1505 | return ret; | |
1506 | } | |
1507 | EXPORT_SYMBOL_GPL(clk_notifier_register); | |
1508 | ||
1509 | /** | |
1510 | * clk_notifier_unregister - remove a clk rate change notifier | |
1511 | * @clk: struct clk * | |
1512 | * @nb: struct notifier_block * with callback info | |
1513 | * | |
1514 | * Request no further notification for changes to 'clk' and frees memory | |
1515 | * allocated in clk_notifier_register. | |
1516 | * | |
1517 | * Returns -EINVAL if called with null arguments; otherwise, passes | |
1518 | * along the return value of srcu_notifier_chain_unregister(). | |
1519 | */ | |
1520 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) | |
1521 | { | |
1522 | struct clk_notifier *cn = NULL; | |
1523 | int ret = -EINVAL; | |
1524 | ||
1525 | if (!clk || !nb) | |
1526 | return -EINVAL; | |
1527 | ||
1528 | mutex_lock(&prepare_lock); | |
1529 | ||
1530 | list_for_each_entry(cn, &clk_notifier_list, node) | |
1531 | if (cn->clk == clk) | |
1532 | break; | |
1533 | ||
1534 | if (cn->clk == clk) { | |
1535 | ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); | |
1536 | ||
1537 | clk->notifier_count--; | |
1538 | ||
1539 | /* XXX the notifier code should handle this better */ | |
1540 | if (!cn->notifier_head.head) { | |
1541 | srcu_cleanup_notifier_head(&cn->notifier_head); | |
1542 | kfree(cn); | |
1543 | } | |
1544 | ||
1545 | } else { | |
1546 | ret = -ENOENT; | |
1547 | } | |
1548 | ||
1549 | mutex_unlock(&prepare_lock); | |
1550 | ||
1551 | return ret; | |
1552 | } | |
1553 | EXPORT_SYMBOL_GPL(clk_notifier_unregister); | |
766e6a4e GL |
1554 | |
1555 | #ifdef CONFIG_OF | |
1556 | /** | |
1557 | * struct of_clk_provider - Clock provider registration structure | |
1558 | * @link: Entry in global list of clock providers | |
1559 | * @node: Pointer to device tree node of clock provider | |
1560 | * @get: Get clock callback. Returns NULL or a struct clk for the | |
1561 | * given clock specifier | |
1562 | * @data: context pointer to be passed into @get callback | |
1563 | */ | |
1564 | struct of_clk_provider { | |
1565 | struct list_head link; | |
1566 | ||
1567 | struct device_node *node; | |
1568 | struct clk *(*get)(struct of_phandle_args *clkspec, void *data); | |
1569 | void *data; | |
1570 | }; | |
1571 | ||
1572 | static LIST_HEAD(of_clk_providers); | |
1573 | static DEFINE_MUTEX(of_clk_lock); | |
1574 | ||
1575 | struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec, | |
1576 | void *data) | |
1577 | { | |
1578 | return data; | |
1579 | } | |
1580 | EXPORT_SYMBOL_GPL(of_clk_src_simple_get); | |
1581 | ||
1582 | /** | |
1583 | * of_clk_add_provider() - Register a clock provider for a node | |
1584 | * @np: Device node pointer associated with clock provider | |
1585 | * @clk_src_get: callback for decoding clock | |
1586 | * @data: context pointer for @clk_src_get callback. | |
1587 | */ | |
1588 | int of_clk_add_provider(struct device_node *np, | |
1589 | struct clk *(*clk_src_get)(struct of_phandle_args *clkspec, | |
1590 | void *data), | |
1591 | void *data) | |
1592 | { | |
1593 | struct of_clk_provider *cp; | |
1594 | ||
1595 | cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL); | |
1596 | if (!cp) | |
1597 | return -ENOMEM; | |
1598 | ||
1599 | cp->node = of_node_get(np); | |
1600 | cp->data = data; | |
1601 | cp->get = clk_src_get; | |
1602 | ||
1603 | mutex_lock(&of_clk_lock); | |
1604 | list_add(&cp->link, &of_clk_providers); | |
1605 | mutex_unlock(&of_clk_lock); | |
1606 | pr_debug("Added clock from %s\n", np->full_name); | |
1607 | ||
1608 | return 0; | |
1609 | } | |
1610 | EXPORT_SYMBOL_GPL(of_clk_add_provider); | |
1611 | ||
1612 | /** | |
1613 | * of_clk_del_provider() - Remove a previously registered clock provider | |
1614 | * @np: Device node pointer associated with clock provider | |
1615 | */ | |
1616 | void of_clk_del_provider(struct device_node *np) | |
1617 | { | |
1618 | struct of_clk_provider *cp; | |
1619 | ||
1620 | mutex_lock(&of_clk_lock); | |
1621 | list_for_each_entry(cp, &of_clk_providers, link) { | |
1622 | if (cp->node == np) { | |
1623 | list_del(&cp->link); | |
1624 | of_node_put(cp->node); | |
1625 | kfree(cp); | |
1626 | break; | |
1627 | } | |
1628 | } | |
1629 | mutex_unlock(&of_clk_lock); | |
1630 | } | |
1631 | EXPORT_SYMBOL_GPL(of_clk_del_provider); | |
1632 | ||
1633 | struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) | |
1634 | { | |
1635 | struct of_clk_provider *provider; | |
1636 | struct clk *clk = ERR_PTR(-ENOENT); | |
1637 | ||
1638 | /* Check if we have such a provider in our array */ | |
1639 | mutex_lock(&of_clk_lock); | |
1640 | list_for_each_entry(provider, &of_clk_providers, link) { | |
1641 | if (provider->node == clkspec->np) | |
1642 | clk = provider->get(clkspec, provider->data); | |
1643 | if (!IS_ERR(clk)) | |
1644 | break; | |
1645 | } | |
1646 | mutex_unlock(&of_clk_lock); | |
1647 | ||
1648 | return clk; | |
1649 | } | |
1650 | ||
1651 | const char *of_clk_get_parent_name(struct device_node *np, int index) | |
1652 | { | |
1653 | struct of_phandle_args clkspec; | |
1654 | const char *clk_name; | |
1655 | int rc; | |
1656 | ||
1657 | if (index < 0) | |
1658 | return NULL; | |
1659 | ||
1660 | rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, | |
1661 | &clkspec); | |
1662 | if (rc) | |
1663 | return NULL; | |
1664 | ||
1665 | if (of_property_read_string_index(clkspec.np, "clock-output-names", | |
1666 | clkspec.args_count ? clkspec.args[0] : 0, | |
1667 | &clk_name) < 0) | |
1668 | clk_name = clkspec.np->name; | |
1669 | ||
1670 | of_node_put(clkspec.np); | |
1671 | return clk_name; | |
1672 | } | |
1673 | EXPORT_SYMBOL_GPL(of_clk_get_parent_name); | |
1674 | ||
1675 | /** | |
1676 | * of_clk_init() - Scan and init clock providers from the DT | |
1677 | * @matches: array of compatible values and init functions for providers. | |
1678 | * | |
1679 | * This function scans the device tree for matching clock providers and | |
1680 | * calls their initialization functions | |
1681 | */ | |
1682 | void __init of_clk_init(const struct of_device_id *matches) | |
1683 | { | |
1684 | struct device_node *np; | |
1685 | ||
1686 | for_each_matching_node(np, matches) { | |
1687 | const struct of_device_id *match = of_match_node(matches, np); | |
1688 | of_clk_init_cb_t clk_init_cb = match->data; | |
1689 | clk_init_cb(np); | |
1690 | } | |
1691 | } | |
1692 | #endif |