xref: /openbmc/linux/drivers/sh/clk/core.c (revision 7fe2f639) 
1 /*
2  * SuperH clock framework
3  *
4  *  Copyright (C) 2005 - 2010  Paul Mundt
5  *
6  * This clock framework is derived from the OMAP version by:
7  *
8  *	Copyright (C) 2004 - 2008 Nokia Corporation
9  *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
10  *
11  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
12  *
13  * This file is subject to the terms and conditions of the GNU General Public
14  * License.  See the file "COPYING" in the main directory of this archive
15  * for more details.
16  */
17 #define pr_fmt(fmt) "clock: " fmt
18 
19 #include <linux/kernel.h>
20 #include <linux/init.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/list.h>
24 #include <linux/syscore_ops.h>
25 #include <linux/seq_file.h>
26 #include <linux/err.h>
27 #include <linux/io.h>
28 #include <linux/debugfs.h>
29 #include <linux/cpufreq.h>
30 #include <linux/clk.h>
31 #include <linux/sh_clk.h>
32 
33 static LIST_HEAD(clock_list);
34 static DEFINE_SPINLOCK(clock_lock);
35 static DEFINE_MUTEX(clock_list_sem);
36 
37 void clk_rate_table_build(struct clk *clk,
38 			  struct cpufreq_frequency_table *freq_table,
39 			  int nr_freqs,
40 			  struct clk_div_mult_table *src_table,
41 			  unsigned long *bitmap)
42 {
43 	unsigned long mult, div;
44 	unsigned long freq;
45 	int i;
46 
47 	clk->nr_freqs = nr_freqs;
48 
49 	for (i = 0; i < nr_freqs; i++) {
50 		div = 1;
51 		mult = 1;
52 
53 		if (src_table->divisors && i < src_table->nr_divisors)
54 			div = src_table->divisors[i];
55 
56 		if (src_table->multipliers && i < src_table->nr_multipliers)
57 			mult = src_table->multipliers[i];
58 
59 		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
60 			freq = CPUFREQ_ENTRY_INVALID;
61 		else
62 			freq = clk->parent->rate * mult / div;
63 
64 		freq_table[i].index = i;
65 		freq_table[i].frequency = freq;
66 	}
67 
68 	/* Termination entry */
69 	freq_table[i].index = i;
70 	freq_table[i].frequency = CPUFREQ_TABLE_END;
71 }
72 
73 struct clk_rate_round_data;
74 
75 struct clk_rate_round_data {
76 	unsigned long rate;
77 	unsigned int min, max;
78 	long (*func)(unsigned int, struct clk_rate_round_data *);
79 	void *arg;
80 };
81 
82 #define for_each_frequency(pos, r, freq)			\
83 	for (pos = r->min, freq = r->func(pos, r);		\
84 	     pos <= r->max; pos++, freq = r->func(pos, r))	\
85 		if (unlikely(freq == 0))			\
86 			;					\
87 		else
88 
89 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
90 {
91 	unsigned long rate_error, rate_error_prev = ~0UL;
92 	unsigned long highest, lowest, freq;
93 	long rate_best_fit = -ENOENT;
94 	int i;
95 
96 	highest = 0;
97 	lowest = ~0UL;
98 
99 	for_each_frequency(i, rounder, freq) {
100 		if (freq > highest)
101 			highest = freq;
102 		if (freq < lowest)
103 			lowest = freq;
104 
105 		rate_error = abs(freq - rounder->rate);
106 		if (rate_error < rate_error_prev) {
107 			rate_best_fit = freq;
108 			rate_error_prev = rate_error;
109 		}
110 
111 		if (rate_error == 0)
112 			break;
113 	}
114 
115 	if (rounder->rate >= highest)
116 		rate_best_fit = highest;
117 	if (rounder->rate <= lowest)
118 		rate_best_fit = lowest;
119 
120 	return rate_best_fit;
121 }
122 
123 static long clk_rate_table_iter(unsigned int pos,
124 				struct clk_rate_round_data *rounder)
125 {
126 	struct cpufreq_frequency_table *freq_table = rounder->arg;
127 	unsigned long freq = freq_table[pos].frequency;
128 
129 	if (freq == CPUFREQ_ENTRY_INVALID)
130 		freq = 0;
131 
132 	return freq;
133 }
134 
135 long clk_rate_table_round(struct clk *clk,
136 			  struct cpufreq_frequency_table *freq_table,
137 			  unsigned long rate)
138 {
139 	struct clk_rate_round_data table_round = {
140 		.min	= 0,
141 		.max	= clk->nr_freqs - 1,
142 		.func	= clk_rate_table_iter,
143 		.arg	= freq_table,
144 		.rate	= rate,
145 	};
146 
147 	if (clk->nr_freqs < 1)
148 		return -ENOSYS;
149 
150 	return clk_rate_round_helper(&table_round);
151 }
152 
153 static long clk_rate_div_range_iter(unsigned int pos,
154 				    struct clk_rate_round_data *rounder)
155 {
156 	return clk_get_rate(rounder->arg) / pos;
157 }
158 
159 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
160 			      unsigned int div_max, unsigned long rate)
161 {
162 	struct clk_rate_round_data div_range_round = {
163 		.min	= div_min,
164 		.max	= div_max,
165 		.func	= clk_rate_div_range_iter,
166 		.arg	= clk_get_parent(clk),
167 		.rate	= rate,
168 	};
169 
170 	return clk_rate_round_helper(&div_range_round);
171 }
172 
173 int clk_rate_table_find(struct clk *clk,
174 			struct cpufreq_frequency_table *freq_table,
175 			unsigned long rate)
176 {
177 	int i;
178 
179 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
180 		unsigned long freq = freq_table[i].frequency;
181 
182 		if (freq == CPUFREQ_ENTRY_INVALID)
183 			continue;
184 
185 		if (freq == rate)
186 			return i;
187 	}
188 
189 	return -ENOENT;
190 }
191 
192 /* Used for clocks that always have same value as the parent clock */
193 unsigned long followparent_recalc(struct clk *clk)
194 {
195 	return clk->parent ? clk->parent->rate : 0;
196 }
197 
198 int clk_reparent(struct clk *child, struct clk *parent)
199 {
200 	list_del_init(&child->sibling);
201 	if (parent)
202 		list_add(&child->sibling, &parent->children);
203 	child->parent = parent;
204 
205 	/* now do the debugfs renaming to reattach the child
206 	   to the proper parent */
207 
208 	return 0;
209 }
210 
211 /* Propagate rate to children */
212 void propagate_rate(struct clk *tclk)
213 {
214 	struct clk *clkp;
215 
216 	list_for_each_entry(clkp, &tclk->children, sibling) {
217 		if (clkp->ops && clkp->ops->recalc)
218 			clkp->rate = clkp->ops->recalc(clkp);
219 
220 		propagate_rate(clkp);
221 	}
222 }
223 
224 static void __clk_disable(struct clk *clk)
225 {
226 	if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
227 		 clk))
228 		return;
229 
230 	if (!(--clk->usecount)) {
231 		if (likely(clk->ops && clk->ops->disable))
232 			clk->ops->disable(clk);
233 		if (likely(clk->parent))
234 			__clk_disable(clk->parent);
235 	}
236 }
237 
238 void clk_disable(struct clk *clk)
239 {
240 	unsigned long flags;
241 
242 	if (!clk)
243 		return;
244 
245 	spin_lock_irqsave(&clock_lock, flags);
246 	__clk_disable(clk);
247 	spin_unlock_irqrestore(&clock_lock, flags);
248 }
249 EXPORT_SYMBOL_GPL(clk_disable);
250 
251 static int __clk_enable(struct clk *clk)
252 {
253 	int ret = 0;
254 
255 	if (clk->usecount++ == 0) {
256 		if (clk->parent) {
257 			ret = __clk_enable(clk->parent);
258 			if (unlikely(ret))
259 				goto err;
260 		}
261 
262 		if (clk->ops && clk->ops->enable) {
263 			ret = clk->ops->enable(clk);
264 			if (ret) {
265 				if (clk->parent)
266 					__clk_disable(clk->parent);
267 				goto err;
268 			}
269 		}
270 	}
271 
272 	return ret;
273 err:
274 	clk->usecount--;
275 	return ret;
276 }
277 
278 int clk_enable(struct clk *clk)
279 {
280 	unsigned long flags;
281 	int ret;
282 
283 	if (!clk)
284 		return -EINVAL;
285 
286 	spin_lock_irqsave(&clock_lock, flags);
287 	ret = __clk_enable(clk);
288 	spin_unlock_irqrestore(&clock_lock, flags);
289 
290 	return ret;
291 }
292 EXPORT_SYMBOL_GPL(clk_enable);
293 
294 static LIST_HEAD(root_clks);
295 
296 /**
297  * recalculate_root_clocks - recalculate and propagate all root clocks
298  *
299  * Recalculates all root clocks (clocks with no parent), which if the
300  * clock's .recalc is set correctly, should also propagate their rates.
301  * Called at init.
302  */
303 void recalculate_root_clocks(void)
304 {
305 	struct clk *clkp;
306 
307 	list_for_each_entry(clkp, &root_clks, sibling) {
308 		if (clkp->ops && clkp->ops->recalc)
309 			clkp->rate = clkp->ops->recalc(clkp);
310 		propagate_rate(clkp);
311 	}
312 }
313 
314 static struct clk_mapping dummy_mapping;
315 
316 static struct clk *lookup_root_clock(struct clk *clk)
317 {
318 	while (clk->parent)
319 		clk = clk->parent;
320 
321 	return clk;
322 }
323 
324 static int clk_establish_mapping(struct clk *clk)
325 {
326 	struct clk_mapping *mapping = clk->mapping;
327 
328 	/*
329 	 * Propagate mappings.
330 	 */
331 	if (!mapping) {
332 		struct clk *clkp;
333 
334 		/*
335 		 * dummy mapping for root clocks with no specified ranges
336 		 */
337 		if (!clk->parent) {
338 			clk->mapping = &dummy_mapping;
339 			return 0;
340 		}
341 
342 		/*
343 		 * If we're on a child clock and it provides no mapping of its
344 		 * own, inherit the mapping from its root clock.
345 		 */
346 		clkp = lookup_root_clock(clk);
347 		mapping = clkp->mapping;
348 		BUG_ON(!mapping);
349 	}
350 
351 	/*
352 	 * Establish initial mapping.
353 	 */
354 	if (!mapping->base && mapping->phys) {
355 		kref_init(&mapping->ref);
356 
357 		mapping->base = ioremap_nocache(mapping->phys, mapping->len);
358 		if (unlikely(!mapping->base))
359 			return -ENXIO;
360 	} else if (mapping->base) {
361 		/*
362 		 * Bump the refcount for an existing mapping
363 		 */
364 		kref_get(&mapping->ref);
365 	}
366 
367 	clk->mapping = mapping;
368 	return 0;
369 }
370 
371 static void clk_destroy_mapping(struct kref *kref)
372 {
373 	struct clk_mapping *mapping;
374 
375 	mapping = container_of(kref, struct clk_mapping, ref);
376 
377 	iounmap(mapping->base);
378 }
379 
380 static void clk_teardown_mapping(struct clk *clk)
381 {
382 	struct clk_mapping *mapping = clk->mapping;
383 
384 	/* Nothing to do */
385 	if (mapping == &dummy_mapping)
386 		return;
387 
388 	kref_put(&mapping->ref, clk_destroy_mapping);
389 	clk->mapping = NULL;
390 }
391 
392 int clk_register(struct clk *clk)
393 {
394 	int ret;
395 
396 	if (clk == NULL || IS_ERR(clk))
397 		return -EINVAL;
398 
399 	/*
400 	 * trap out already registered clocks
401 	 */
402 	if (clk->node.next || clk->node.prev)
403 		return 0;
404 
405 	mutex_lock(&clock_list_sem);
406 
407 	INIT_LIST_HEAD(&clk->children);
408 	clk->usecount = 0;
409 
410 	ret = clk_establish_mapping(clk);
411 	if (unlikely(ret))
412 		goto out_unlock;
413 
414 	if (clk->parent)
415 		list_add(&clk->sibling, &clk->parent->children);
416 	else
417 		list_add(&clk->sibling, &root_clks);
418 
419 	list_add(&clk->node, &clock_list);
420 
421 #ifdef CONFIG_SH_CLK_CPG_LEGACY
422 	if (clk->ops && clk->ops->init)
423 		clk->ops->init(clk);
424 #endif
425 
426 out_unlock:
427 	mutex_unlock(&clock_list_sem);
428 
429 	return ret;
430 }
431 EXPORT_SYMBOL_GPL(clk_register);
432 
433 void clk_unregister(struct clk *clk)
434 {
435 	mutex_lock(&clock_list_sem);
436 	list_del(&clk->sibling);
437 	list_del(&clk->node);
438 	clk_teardown_mapping(clk);
439 	mutex_unlock(&clock_list_sem);
440 }
441 EXPORT_SYMBOL_GPL(clk_unregister);
442 
443 void clk_enable_init_clocks(void)
444 {
445 	struct clk *clkp;
446 
447 	list_for_each_entry(clkp, &clock_list, node)
448 		if (clkp->flags & CLK_ENABLE_ON_INIT)
449 			clk_enable(clkp);
450 }
451 
452 unsigned long clk_get_rate(struct clk *clk)
453 {
454 	return clk->rate;
455 }
456 EXPORT_SYMBOL_GPL(clk_get_rate);
457 
458 int clk_set_rate(struct clk *clk, unsigned long rate)
459 {
460 	int ret = -EOPNOTSUPP;
461 	unsigned long flags;
462 
463 	spin_lock_irqsave(&clock_lock, flags);
464 
465 	if (likely(clk->ops && clk->ops->set_rate)) {
466 		ret = clk->ops->set_rate(clk, rate);
467 		if (ret != 0)
468 			goto out_unlock;
469 	} else {
470 		clk->rate = rate;
471 		ret = 0;
472 	}
473 
474 	if (clk->ops && clk->ops->recalc)
475 		clk->rate = clk->ops->recalc(clk);
476 
477 	propagate_rate(clk);
478 
479 out_unlock:
480 	spin_unlock_irqrestore(&clock_lock, flags);
481 
482 	return ret;
483 }
484 EXPORT_SYMBOL_GPL(clk_set_rate);
485 
486 int clk_set_parent(struct clk *clk, struct clk *parent)
487 {
488 	unsigned long flags;
489 	int ret = -EINVAL;
490 
491 	if (!parent || !clk)
492 		return ret;
493 	if (clk->parent == parent)
494 		return 0;
495 
496 	spin_lock_irqsave(&clock_lock, flags);
497 	if (clk->usecount == 0) {
498 		if (clk->ops->set_parent)
499 			ret = clk->ops->set_parent(clk, parent);
500 		else
501 			ret = clk_reparent(clk, parent);
502 
503 		if (ret == 0) {
504 			if (clk->ops->recalc)
505 				clk->rate = clk->ops->recalc(clk);
506 			pr_debug("set parent of %p to %p (new rate %ld)\n",
507 				 clk, clk->parent, clk->rate);
508 			propagate_rate(clk);
509 		}
510 	} else
511 		ret = -EBUSY;
512 	spin_unlock_irqrestore(&clock_lock, flags);
513 
514 	return ret;
515 }
516 EXPORT_SYMBOL_GPL(clk_set_parent);
517 
518 struct clk *clk_get_parent(struct clk *clk)
519 {
520 	return clk->parent;
521 }
522 EXPORT_SYMBOL_GPL(clk_get_parent);
523 
524 long clk_round_rate(struct clk *clk, unsigned long rate)
525 {
526 	if (likely(clk->ops && clk->ops->round_rate)) {
527 		unsigned long flags, rounded;
528 
529 		spin_lock_irqsave(&clock_lock, flags);
530 		rounded = clk->ops->round_rate(clk, rate);
531 		spin_unlock_irqrestore(&clock_lock, flags);
532 
533 		return rounded;
534 	}
535 
536 	return clk_get_rate(clk);
537 }
538 EXPORT_SYMBOL_GPL(clk_round_rate);
539 
540 long clk_round_parent(struct clk *clk, unsigned long target,
541 		      unsigned long *best_freq, unsigned long *parent_freq,
542 		      unsigned int div_min, unsigned int div_max)
543 {
544 	struct cpufreq_frequency_table *freq, *best = NULL;
545 	unsigned long error = ULONG_MAX, freq_high, freq_low, div;
546 	struct clk *parent = clk_get_parent(clk);
547 
548 	if (!parent) {
549 		*parent_freq = 0;
550 		*best_freq = clk_round_rate(clk, target);
551 		return abs(target - *best_freq);
552 	}
553 
554 	for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
555 	     freq++) {
556 		if (freq->frequency == CPUFREQ_ENTRY_INVALID)
557 			continue;
558 
559 		if (unlikely(freq->frequency / target <= div_min - 1)) {
560 			unsigned long freq_max;
561 
562 			freq_max = (freq->frequency + div_min / 2) / div_min;
563 			if (error > target - freq_max) {
564 				error = target - freq_max;
565 				best = freq;
566 				if (best_freq)
567 					*best_freq = freq_max;
568 			}
569 
570 			pr_debug("too low freq %u, error %lu\n", freq->frequency,
571 				 target - freq_max);
572 
573 			if (!error)
574 				break;
575 
576 			continue;
577 		}
578 
579 		if (unlikely(freq->frequency / target >= div_max)) {
580 			unsigned long freq_min;
581 
582 			freq_min = (freq->frequency + div_max / 2) / div_max;
583 			if (error > freq_min - target) {
584 				error = freq_min - target;
585 				best = freq;
586 				if (best_freq)
587 					*best_freq = freq_min;
588 			}
589 
590 			pr_debug("too high freq %u, error %lu\n", freq->frequency,
591 				 freq_min - target);
592 
593 			if (!error)
594 				break;
595 
596 			continue;
597 		}
598 
599 		div = freq->frequency / target;
600 		freq_high = freq->frequency / div;
601 		freq_low = freq->frequency / (div + 1);
602 
603 		if (freq_high - target < error) {
604 			error = freq_high - target;
605 			best = freq;
606 			if (best_freq)
607 				*best_freq = freq_high;
608 		}
609 
610 		if (target - freq_low < error) {
611 			error = target - freq_low;
612 			best = freq;
613 			if (best_freq)
614 				*best_freq = freq_low;
615 		}
616 
617 		pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
618 			 freq->frequency, div, freq_high, div + 1, freq_low,
619 			 *best_freq, best->frequency);
620 
621 		if (!error)
622 			break;
623 	}
624 
625 	if (parent_freq)
626 		*parent_freq = best->frequency;
627 
628 	return error;
629 }
630 EXPORT_SYMBOL_GPL(clk_round_parent);
631 
632 #ifdef CONFIG_PM
633 static void clks_core_resume(void)
634 {
635 	struct clk *clkp;
636 
637 	list_for_each_entry(clkp, &clock_list, node) {
638 		if (likely(clkp->usecount && clkp->ops)) {
639 			unsigned long rate = clkp->rate;
640 
641 			if (likely(clkp->ops->set_parent))
642 				clkp->ops->set_parent(clkp,
643 					clkp->parent);
644 			if (likely(clkp->ops->set_rate))
645 				clkp->ops->set_rate(clkp, rate);
646 			else if (likely(clkp->ops->recalc))
647 				clkp->rate = clkp->ops->recalc(clkp);
648 		}
649 	}
650 }
651 
652 static struct syscore_ops clks_syscore_ops = {
653 	.resume = clks_core_resume,
654 };
655 
656 static int __init clk_syscore_init(void)
657 {
658 	register_syscore_ops(&clks_syscore_ops);
659 
660 	return 0;
661 }
662 subsys_initcall(clk_syscore_init);
663 #endif
664 
665 /*
666  *	debugfs support to trace clock tree hierarchy and attributes
667  */
668 static struct dentry *clk_debugfs_root;
669 
670 static int clk_debugfs_register_one(struct clk *c)
671 {
672 	int err;
673 	struct dentry *d, *child, *child_tmp;
674 	struct clk *pa = c->parent;
675 	char s[255];
676 	char *p = s;
677 
678 	p += sprintf(p, "%p", c);
679 	d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
680 	if (!d)
681 		return -ENOMEM;
682 	c->dentry = d;
683 
684 	d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
685 	if (!d) {
686 		err = -ENOMEM;
687 		goto err_out;
688 	}
689 	d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
690 	if (!d) {
691 		err = -ENOMEM;
692 		goto err_out;
693 	}
694 	d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
695 	if (!d) {
696 		err = -ENOMEM;
697 		goto err_out;
698 	}
699 	return 0;
700 
701 err_out:
702 	d = c->dentry;
703 	list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
704 		debugfs_remove(child);
705 	debugfs_remove(c->dentry);
706 	return err;
707 }
708 
709 static int clk_debugfs_register(struct clk *c)
710 {
711 	int err;
712 	struct clk *pa = c->parent;
713 
714 	if (pa && !pa->dentry) {
715 		err = clk_debugfs_register(pa);
716 		if (err)
717 			return err;
718 	}
719 
720 	if (!c->dentry) {
721 		err = clk_debugfs_register_one(c);
722 		if (err)
723 			return err;
724 	}
725 	return 0;
726 }
727 
728 static int __init clk_debugfs_init(void)
729 {
730 	struct clk *c;
731 	struct dentry *d;
732 	int err;
733 
734 	d = debugfs_create_dir("clock", NULL);
735 	if (!d)
736 		return -ENOMEM;
737 	clk_debugfs_root = d;
738 
739 	list_for_each_entry(c, &clock_list, node) {
740 		err = clk_debugfs_register(c);
741 		if (err)
742 			goto err_out;
743 	}
744 	return 0;
745 err_out:
746 	debugfs_remove_recursive(clk_debugfs_root);
747 	return err;
748 }
749 late_initcall(clk_debugfs_init);
750