xref: /openbmc/linux/drivers/sh/clk/core.c (revision 8a10bc9d) 
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/cpufreq.h>
29 #include <linux/clk.h>
30 #include <linux/sh_clk.h>
31 
32 static LIST_HEAD(clock_list);
33 static DEFINE_SPINLOCK(clock_lock);
34 static DEFINE_MUTEX(clock_list_sem);
35 
36 /* clock disable operations are not passed on to hardware during boot */
37 static int allow_disable;
38 
39 void clk_rate_table_build(struct clk *clk,
40 			  struct cpufreq_frequency_table *freq_table,
41 			  int nr_freqs,
42 			  struct clk_div_mult_table *src_table,
43 			  unsigned long *bitmap)
44 {
45 	unsigned long mult, div;
46 	unsigned long freq;
47 	int i;
48 
49 	clk->nr_freqs = nr_freqs;
50 
51 	for (i = 0; i < nr_freqs; i++) {
52 		div = 1;
53 		mult = 1;
54 
55 		if (src_table->divisors && i < src_table->nr_divisors)
56 			div = src_table->divisors[i];
57 
58 		if (src_table->multipliers && i < src_table->nr_multipliers)
59 			mult = src_table->multipliers[i];
60 
61 		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
62 			freq = CPUFREQ_ENTRY_INVALID;
63 		else
64 			freq = clk->parent->rate * mult / div;
65 
66 		freq_table[i].driver_data = i;
67 		freq_table[i].frequency = freq;
68 	}
69 
70 	/* Termination entry */
71 	freq_table[i].driver_data = i;
72 	freq_table[i].frequency = CPUFREQ_TABLE_END;
73 }
74 
75 struct clk_rate_round_data;
76 
77 struct clk_rate_round_data {
78 	unsigned long rate;
79 	unsigned int min, max;
80 	long (*func)(unsigned int, struct clk_rate_round_data *);
81 	void *arg;
82 };
83 
84 #define for_each_frequency(pos, r, freq)			\
85 	for (pos = r->min, freq = r->func(pos, r);		\
86 	     pos <= r->max; pos++, freq = r->func(pos, r))	\
87 		if (unlikely(freq == 0))			\
88 			;					\
89 		else
90 
91 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
92 {
93 	unsigned long rate_error, rate_error_prev = ~0UL;
94 	unsigned long highest, lowest, freq;
95 	long rate_best_fit = -ENOENT;
96 	int i;
97 
98 	highest = 0;
99 	lowest = ~0UL;
100 
101 	for_each_frequency(i, rounder, freq) {
102 		if (freq > highest)
103 			highest = freq;
104 		if (freq < lowest)
105 			lowest = freq;
106 
107 		rate_error = abs(freq - rounder->rate);
108 		if (rate_error < rate_error_prev) {
109 			rate_best_fit = freq;
110 			rate_error_prev = rate_error;
111 		}
112 
113 		if (rate_error == 0)
114 			break;
115 	}
116 
117 	if (rounder->rate >= highest)
118 		rate_best_fit = highest;
119 	if (rounder->rate <= lowest)
120 		rate_best_fit = lowest;
121 
122 	return rate_best_fit;
123 }
124 
125 static long clk_rate_table_iter(unsigned int pos,
126 				struct clk_rate_round_data *rounder)
127 {
128 	struct cpufreq_frequency_table *freq_table = rounder->arg;
129 	unsigned long freq = freq_table[pos].frequency;
130 
131 	if (freq == CPUFREQ_ENTRY_INVALID)
132 		freq = 0;
133 
134 	return freq;
135 }
136 
137 long clk_rate_table_round(struct clk *clk,
138 			  struct cpufreq_frequency_table *freq_table,
139 			  unsigned long rate)
140 {
141 	struct clk_rate_round_data table_round = {
142 		.min	= 0,
143 		.max	= clk->nr_freqs - 1,
144 		.func	= clk_rate_table_iter,
145 		.arg	= freq_table,
146 		.rate	= rate,
147 	};
148 
149 	if (clk->nr_freqs < 1)
150 		return -ENOSYS;
151 
152 	return clk_rate_round_helper(&table_round);
153 }
154 
155 static long clk_rate_div_range_iter(unsigned int pos,
156 				    struct clk_rate_round_data *rounder)
157 {
158 	return clk_get_rate(rounder->arg) / pos;
159 }
160 
161 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
162 			      unsigned int div_max, unsigned long rate)
163 {
164 	struct clk_rate_round_data div_range_round = {
165 		.min	= div_min,
166 		.max	= div_max,
167 		.func	= clk_rate_div_range_iter,
168 		.arg	= clk_get_parent(clk),
169 		.rate	= rate,
170 	};
171 
172 	return clk_rate_round_helper(&div_range_round);
173 }
174 
175 static long clk_rate_mult_range_iter(unsigned int pos,
176 				      struct clk_rate_round_data *rounder)
177 {
178 	return clk_get_rate(rounder->arg) * pos;
179 }
180 
181 long clk_rate_mult_range_round(struct clk *clk, unsigned int mult_min,
182 			       unsigned int mult_max, unsigned long rate)
183 {
184 	struct clk_rate_round_data mult_range_round = {
185 		.min	= mult_min,
186 		.max	= mult_max,
187 		.func	= clk_rate_mult_range_iter,
188 		.arg	= clk_get_parent(clk),
189 		.rate	= rate,
190 	};
191 
192 	return clk_rate_round_helper(&mult_range_round);
193 }
194 
195 int clk_rate_table_find(struct clk *clk,
196 			struct cpufreq_frequency_table *freq_table,
197 			unsigned long rate)
198 {
199 	int i;
200 
201 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
202 		unsigned long freq = freq_table[i].frequency;
203 
204 		if (freq == CPUFREQ_ENTRY_INVALID)
205 			continue;
206 
207 		if (freq == rate)
208 			return i;
209 	}
210 
211 	return -ENOENT;
212 }
213 
214 /* Used for clocks that always have same value as the parent clock */
215 unsigned long followparent_recalc(struct clk *clk)
216 {
217 	return clk->parent ? clk->parent->rate : 0;
218 }
219 
220 int clk_reparent(struct clk *child, struct clk *parent)
221 {
222 	list_del_init(&child->sibling);
223 	if (parent)
224 		list_add(&child->sibling, &parent->children);
225 	child->parent = parent;
226 
227 	return 0;
228 }
229 
230 /* Propagate rate to children */
231 void propagate_rate(struct clk *tclk)
232 {
233 	struct clk *clkp;
234 
235 	list_for_each_entry(clkp, &tclk->children, sibling) {
236 		if (clkp->ops && clkp->ops->recalc)
237 			clkp->rate = clkp->ops->recalc(clkp);
238 
239 		propagate_rate(clkp);
240 	}
241 }
242 
243 static void __clk_disable(struct clk *clk)
244 {
245 	if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
246 		 clk))
247 		return;
248 
249 	if (!(--clk->usecount)) {
250 		if (likely(allow_disable && clk->ops && clk->ops->disable))
251 			clk->ops->disable(clk);
252 		if (likely(clk->parent))
253 			__clk_disable(clk->parent);
254 	}
255 }
256 
257 void clk_disable(struct clk *clk)
258 {
259 	unsigned long flags;
260 
261 	if (!clk)
262 		return;
263 
264 	spin_lock_irqsave(&clock_lock, flags);
265 	__clk_disable(clk);
266 	spin_unlock_irqrestore(&clock_lock, flags);
267 }
268 EXPORT_SYMBOL_GPL(clk_disable);
269 
270 static int __clk_enable(struct clk *clk)
271 {
272 	int ret = 0;
273 
274 	if (clk->usecount++ == 0) {
275 		if (clk->parent) {
276 			ret = __clk_enable(clk->parent);
277 			if (unlikely(ret))
278 				goto err;
279 		}
280 
281 		if (clk->ops && clk->ops->enable) {
282 			ret = clk->ops->enable(clk);
283 			if (ret) {
284 				if (clk->parent)
285 					__clk_disable(clk->parent);
286 				goto err;
287 			}
288 		}
289 	}
290 
291 	return ret;
292 err:
293 	clk->usecount--;
294 	return ret;
295 }
296 
297 int clk_enable(struct clk *clk)
298 {
299 	unsigned long flags;
300 	int ret;
301 
302 	if (!clk)
303 		return -EINVAL;
304 
305 	spin_lock_irqsave(&clock_lock, flags);
306 	ret = __clk_enable(clk);
307 	spin_unlock_irqrestore(&clock_lock, flags);
308 
309 	return ret;
310 }
311 EXPORT_SYMBOL_GPL(clk_enable);
312 
313 static LIST_HEAD(root_clks);
314 
315 /**
316  * recalculate_root_clocks - recalculate and propagate all root clocks
317  *
318  * Recalculates all root clocks (clocks with no parent), which if the
319  * clock's .recalc is set correctly, should also propagate their rates.
320  * Called at init.
321  */
322 void recalculate_root_clocks(void)
323 {
324 	struct clk *clkp;
325 
326 	list_for_each_entry(clkp, &root_clks, sibling) {
327 		if (clkp->ops && clkp->ops->recalc)
328 			clkp->rate = clkp->ops->recalc(clkp);
329 		propagate_rate(clkp);
330 	}
331 }
332 
333 static struct clk_mapping dummy_mapping;
334 
335 static struct clk *lookup_root_clock(struct clk *clk)
336 {
337 	while (clk->parent)
338 		clk = clk->parent;
339 
340 	return clk;
341 }
342 
343 static int clk_establish_mapping(struct clk *clk)
344 {
345 	struct clk_mapping *mapping = clk->mapping;
346 
347 	/*
348 	 * Propagate mappings.
349 	 */
350 	if (!mapping) {
351 		struct clk *clkp;
352 
353 		/*
354 		 * dummy mapping for root clocks with no specified ranges
355 		 */
356 		if (!clk->parent) {
357 			clk->mapping = &dummy_mapping;
358 			goto out;
359 		}
360 
361 		/*
362 		 * If we're on a child clock and it provides no mapping of its
363 		 * own, inherit the mapping from its root clock.
364 		 */
365 		clkp = lookup_root_clock(clk);
366 		mapping = clkp->mapping;
367 		BUG_ON(!mapping);
368 	}
369 
370 	/*
371 	 * Establish initial mapping.
372 	 */
373 	if (!mapping->base && mapping->phys) {
374 		kref_init(&mapping->ref);
375 
376 		mapping->base = ioremap_nocache(mapping->phys, mapping->len);
377 		if (unlikely(!mapping->base))
378 			return -ENXIO;
379 	} else if (mapping->base) {
380 		/*
381 		 * Bump the refcount for an existing mapping
382 		 */
383 		kref_get(&mapping->ref);
384 	}
385 
386 	clk->mapping = mapping;
387 out:
388 	clk->mapped_reg = clk->mapping->base;
389 	clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
390 	return 0;
391 }
392 
393 static void clk_destroy_mapping(struct kref *kref)
394 {
395 	struct clk_mapping *mapping;
396 
397 	mapping = container_of(kref, struct clk_mapping, ref);
398 
399 	iounmap(mapping->base);
400 }
401 
402 static void clk_teardown_mapping(struct clk *clk)
403 {
404 	struct clk_mapping *mapping = clk->mapping;
405 
406 	/* Nothing to do */
407 	if (mapping == &dummy_mapping)
408 		goto out;
409 
410 	kref_put(&mapping->ref, clk_destroy_mapping);
411 	clk->mapping = NULL;
412 out:
413 	clk->mapped_reg = NULL;
414 }
415 
416 int clk_register(struct clk *clk)
417 {
418 	int ret;
419 
420 	if (IS_ERR_OR_NULL(clk))
421 		return -EINVAL;
422 
423 	/*
424 	 * trap out already registered clocks
425 	 */
426 	if (clk->node.next || clk->node.prev)
427 		return 0;
428 
429 	mutex_lock(&clock_list_sem);
430 
431 	INIT_LIST_HEAD(&clk->children);
432 	clk->usecount = 0;
433 
434 	ret = clk_establish_mapping(clk);
435 	if (unlikely(ret))
436 		goto out_unlock;
437 
438 	if (clk->parent)
439 		list_add(&clk->sibling, &clk->parent->children);
440 	else
441 		list_add(&clk->sibling, &root_clks);
442 
443 	list_add(&clk->node, &clock_list);
444 
445 #ifdef CONFIG_SH_CLK_CPG_LEGACY
446 	if (clk->ops && clk->ops->init)
447 		clk->ops->init(clk);
448 #endif
449 
450 out_unlock:
451 	mutex_unlock(&clock_list_sem);
452 
453 	return ret;
454 }
455 EXPORT_SYMBOL_GPL(clk_register);
456 
457 void clk_unregister(struct clk *clk)
458 {
459 	mutex_lock(&clock_list_sem);
460 	list_del(&clk->sibling);
461 	list_del(&clk->node);
462 	clk_teardown_mapping(clk);
463 	mutex_unlock(&clock_list_sem);
464 }
465 EXPORT_SYMBOL_GPL(clk_unregister);
466 
467 void clk_enable_init_clocks(void)
468 {
469 	struct clk *clkp;
470 
471 	list_for_each_entry(clkp, &clock_list, node)
472 		if (clkp->flags & CLK_ENABLE_ON_INIT)
473 			clk_enable(clkp);
474 }
475 
476 unsigned long clk_get_rate(struct clk *clk)
477 {
478 	return clk->rate;
479 }
480 EXPORT_SYMBOL_GPL(clk_get_rate);
481 
482 int clk_set_rate(struct clk *clk, unsigned long rate)
483 {
484 	int ret = -EOPNOTSUPP;
485 	unsigned long flags;
486 
487 	spin_lock_irqsave(&clock_lock, flags);
488 
489 	if (likely(clk->ops && clk->ops->set_rate)) {
490 		ret = clk->ops->set_rate(clk, rate);
491 		if (ret != 0)
492 			goto out_unlock;
493 	} else {
494 		clk->rate = rate;
495 		ret = 0;
496 	}
497 
498 	if (clk->ops && clk->ops->recalc)
499 		clk->rate = clk->ops->recalc(clk);
500 
501 	propagate_rate(clk);
502 
503 out_unlock:
504 	spin_unlock_irqrestore(&clock_lock, flags);
505 
506 	return ret;
507 }
508 EXPORT_SYMBOL_GPL(clk_set_rate);
509 
510 int clk_set_parent(struct clk *clk, struct clk *parent)
511 {
512 	unsigned long flags;
513 	int ret = -EINVAL;
514 
515 	if (!parent || !clk)
516 		return ret;
517 	if (clk->parent == parent)
518 		return 0;
519 
520 	spin_lock_irqsave(&clock_lock, flags);
521 	if (clk->usecount == 0) {
522 		if (clk->ops->set_parent)
523 			ret = clk->ops->set_parent(clk, parent);
524 		else
525 			ret = clk_reparent(clk, parent);
526 
527 		if (ret == 0) {
528 			if (clk->ops->recalc)
529 				clk->rate = clk->ops->recalc(clk);
530 			pr_debug("set parent of %p to %p (new rate %ld)\n",
531 				 clk, clk->parent, clk->rate);
532 			propagate_rate(clk);
533 		}
534 	} else
535 		ret = -EBUSY;
536 	spin_unlock_irqrestore(&clock_lock, flags);
537 
538 	return ret;
539 }
540 EXPORT_SYMBOL_GPL(clk_set_parent);
541 
542 struct clk *clk_get_parent(struct clk *clk)
543 {
544 	return clk->parent;
545 }
546 EXPORT_SYMBOL_GPL(clk_get_parent);
547 
548 long clk_round_rate(struct clk *clk, unsigned long rate)
549 {
550 	if (likely(clk->ops && clk->ops->round_rate)) {
551 		unsigned long flags, rounded;
552 
553 		spin_lock_irqsave(&clock_lock, flags);
554 		rounded = clk->ops->round_rate(clk, rate);
555 		spin_unlock_irqrestore(&clock_lock, flags);
556 
557 		return rounded;
558 	}
559 
560 	return clk_get_rate(clk);
561 }
562 EXPORT_SYMBOL_GPL(clk_round_rate);
563 
564 long clk_round_parent(struct clk *clk, unsigned long target,
565 		      unsigned long *best_freq, unsigned long *parent_freq,
566 		      unsigned int div_min, unsigned int div_max)
567 {
568 	struct cpufreq_frequency_table *freq, *best = NULL;
569 	unsigned long error = ULONG_MAX, freq_high, freq_low, div;
570 	struct clk *parent = clk_get_parent(clk);
571 
572 	if (!parent) {
573 		*parent_freq = 0;
574 		*best_freq = clk_round_rate(clk, target);
575 		return abs(target - *best_freq);
576 	}
577 
578 	for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
579 	     freq++) {
580 		if (freq->frequency == CPUFREQ_ENTRY_INVALID)
581 			continue;
582 
583 		if (unlikely(freq->frequency / target <= div_min - 1)) {
584 			unsigned long freq_max;
585 
586 			freq_max = (freq->frequency + div_min / 2) / div_min;
587 			if (error > target - freq_max) {
588 				error = target - freq_max;
589 				best = freq;
590 				if (best_freq)
591 					*best_freq = freq_max;
592 			}
593 
594 			pr_debug("too low freq %u, error %lu\n", freq->frequency,
595 				 target - freq_max);
596 
597 			if (!error)
598 				break;
599 
600 			continue;
601 		}
602 
603 		if (unlikely(freq->frequency / target >= div_max)) {
604 			unsigned long freq_min;
605 
606 			freq_min = (freq->frequency + div_max / 2) / div_max;
607 			if (error > freq_min - target) {
608 				error = freq_min - target;
609 				best = freq;
610 				if (best_freq)
611 					*best_freq = freq_min;
612 			}
613 
614 			pr_debug("too high freq %u, error %lu\n", freq->frequency,
615 				 freq_min - target);
616 
617 			if (!error)
618 				break;
619 
620 			continue;
621 		}
622 
623 		div = freq->frequency / target;
624 		freq_high = freq->frequency / div;
625 		freq_low = freq->frequency / (div + 1);
626 
627 		if (freq_high - target < error) {
628 			error = freq_high - target;
629 			best = freq;
630 			if (best_freq)
631 				*best_freq = freq_high;
632 		}
633 
634 		if (target - freq_low < error) {
635 			error = target - freq_low;
636 			best = freq;
637 			if (best_freq)
638 				*best_freq = freq_low;
639 		}
640 
641 		pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
642 			 freq->frequency, div, freq_high, div + 1, freq_low,
643 			 *best_freq, best->frequency);
644 
645 		if (!error)
646 			break;
647 	}
648 
649 	if (parent_freq)
650 		*parent_freq = best->frequency;
651 
652 	return error;
653 }
654 EXPORT_SYMBOL_GPL(clk_round_parent);
655 
656 #ifdef CONFIG_PM
657 static void clks_core_resume(void)
658 {
659 	struct clk *clkp;
660 
661 	list_for_each_entry(clkp, &clock_list, node) {
662 		if (likely(clkp->usecount && clkp->ops)) {
663 			unsigned long rate = clkp->rate;
664 
665 			if (likely(clkp->ops->set_parent))
666 				clkp->ops->set_parent(clkp,
667 					clkp->parent);
668 			if (likely(clkp->ops->set_rate))
669 				clkp->ops->set_rate(clkp, rate);
670 			else if (likely(clkp->ops->recalc))
671 				clkp->rate = clkp->ops->recalc(clkp);
672 		}
673 	}
674 }
675 
676 static struct syscore_ops clks_syscore_ops = {
677 	.resume = clks_core_resume,
678 };
679 
680 static int __init clk_syscore_init(void)
681 {
682 	register_syscore_ops(&clks_syscore_ops);
683 
684 	return 0;
685 }
686 subsys_initcall(clk_syscore_init);
687 #endif
688 
689 static int __init clk_late_init(void)
690 {
691 	unsigned long flags;
692 	struct clk *clk;
693 
694 	/* disable all clocks with zero use count */
695 	mutex_lock(&clock_list_sem);
696 	spin_lock_irqsave(&clock_lock, flags);
697 
698 	list_for_each_entry(clk, &clock_list, node)
699 		if (!clk->usecount && clk->ops && clk->ops->disable)
700 			clk->ops->disable(clk);
701 
702 	/* from now on allow clock disable operations */
703 	allow_disable = 1;
704 
705 	spin_unlock_irqrestore(&clock_lock, flags);
706 	mutex_unlock(&clock_list_sem);
707 	return 0;
708 }
709 late_initcall(clk_late_init);
710