xref: /openbmc/linux/drivers/sh/clk/core.c (revision ff30bd6a)
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 
clk_rate_table_build(struct clk * clk,struct cpufreq_frequency_table * freq_table,int nr_freqs,struct clk_div_mult_table * src_table,unsigned long * bitmap)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 
clk_rate_round_helper(struct clk_rate_round_data * rounder)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 
clk_rate_table_iter(unsigned int pos,struct clk_rate_round_data * rounder)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 
clk_rate_table_round(struct clk * clk,struct cpufreq_frequency_table * freq_table,unsigned long rate)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 
clk_rate_div_range_iter(unsigned int pos,struct clk_rate_round_data * rounder)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 
clk_rate_div_range_round(struct clk * clk,unsigned int div_min,unsigned int div_max,unsigned long rate)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 
clk_rate_mult_range_iter(unsigned int pos,struct clk_rate_round_data * rounder)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 
clk_rate_mult_range_round(struct clk * clk,unsigned int mult_min,unsigned int mult_max,unsigned long rate)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 
clk_rate_table_find(struct clk * clk,struct cpufreq_frequency_table * freq_table,unsigned long rate)195 int clk_rate_table_find(struct clk *clk,
196 			struct cpufreq_frequency_table *freq_table,
197 			unsigned long rate)
198 {
199 	struct cpufreq_frequency_table *pos;
200 	int idx;
201 
202 	cpufreq_for_each_valid_entry_idx(pos, freq_table, idx)
203 		if (pos->frequency == rate)
204 			return idx;
205 
206 	return -ENOENT;
207 }
208 
209 /* Used for clocks that always have same value as the parent clock */
followparent_recalc(struct clk * clk)210 unsigned long followparent_recalc(struct clk *clk)
211 {
212 	return clk->parent ? clk->parent->rate : 0;
213 }
214 
clk_reparent(struct clk * child,struct clk * parent)215 int clk_reparent(struct clk *child, struct clk *parent)
216 {
217 	list_del_init(&child->sibling);
218 	if (parent)
219 		list_add(&child->sibling, &parent->children);
220 	child->parent = parent;
221 
222 	return 0;
223 }
224 
225 /* Propagate rate to children */
propagate_rate(struct clk * tclk)226 void propagate_rate(struct clk *tclk)
227 {
228 	struct clk *clkp;
229 
230 	list_for_each_entry(clkp, &tclk->children, sibling) {
231 		if (clkp->ops && clkp->ops->recalc)
232 			clkp->rate = clkp->ops->recalc(clkp);
233 
234 		propagate_rate(clkp);
235 	}
236 }
237 
__clk_disable(struct clk * clk)238 static void __clk_disable(struct clk *clk)
239 {
240 	if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
241 		 clk))
242 		return;
243 
244 	if (!(--clk->usecount)) {
245 		if (likely(allow_disable && clk->ops && clk->ops->disable))
246 			clk->ops->disable(clk);
247 		if (likely(clk->parent))
248 			__clk_disable(clk->parent);
249 	}
250 }
251 
clk_disable(struct clk * clk)252 void clk_disable(struct clk *clk)
253 {
254 	unsigned long flags;
255 
256 	if (!clk)
257 		return;
258 
259 	spin_lock_irqsave(&clock_lock, flags);
260 	__clk_disable(clk);
261 	spin_unlock_irqrestore(&clock_lock, flags);
262 }
263 EXPORT_SYMBOL_GPL(clk_disable);
264 
__clk_enable(struct clk * clk)265 static int __clk_enable(struct clk *clk)
266 {
267 	int ret = 0;
268 
269 	if (clk->usecount++ == 0) {
270 		if (clk->parent) {
271 			ret = __clk_enable(clk->parent);
272 			if (unlikely(ret))
273 				goto err;
274 		}
275 
276 		if (clk->ops && clk->ops->enable) {
277 			ret = clk->ops->enable(clk);
278 			if (ret) {
279 				if (clk->parent)
280 					__clk_disable(clk->parent);
281 				goto err;
282 			}
283 		}
284 	}
285 
286 	return ret;
287 err:
288 	clk->usecount--;
289 	return ret;
290 }
291 
clk_enable(struct clk * clk)292 int clk_enable(struct clk *clk)
293 {
294 	unsigned long flags;
295 	int ret;
296 
297 	if (!clk)
298 		return 0;
299 
300 	spin_lock_irqsave(&clock_lock, flags);
301 	ret = __clk_enable(clk);
302 	spin_unlock_irqrestore(&clock_lock, flags);
303 
304 	return ret;
305 }
306 EXPORT_SYMBOL_GPL(clk_enable);
307 
308 static LIST_HEAD(root_clks);
309 
310 /**
311  * recalculate_root_clocks - recalculate and propagate all root clocks
312  *
313  * Recalculates all root clocks (clocks with no parent), which if the
314  * clock's .recalc is set correctly, should also propagate their rates.
315  * Called at init.
316  */
recalculate_root_clocks(void)317 void recalculate_root_clocks(void)
318 {
319 	struct clk *clkp;
320 
321 	list_for_each_entry(clkp, &root_clks, sibling) {
322 		if (clkp->ops && clkp->ops->recalc)
323 			clkp->rate = clkp->ops->recalc(clkp);
324 		propagate_rate(clkp);
325 	}
326 }
327 
328 static struct clk_mapping dummy_mapping;
329 
lookup_root_clock(struct clk * clk)330 static struct clk *lookup_root_clock(struct clk *clk)
331 {
332 	while (clk->parent)
333 		clk = clk->parent;
334 
335 	return clk;
336 }
337 
clk_establish_mapping(struct clk * clk)338 static int clk_establish_mapping(struct clk *clk)
339 {
340 	struct clk_mapping *mapping = clk->mapping;
341 
342 	/*
343 	 * Propagate mappings.
344 	 */
345 	if (!mapping) {
346 		struct clk *clkp;
347 
348 		/*
349 		 * dummy mapping for root clocks with no specified ranges
350 		 */
351 		if (!clk->parent) {
352 			clk->mapping = &dummy_mapping;
353 			goto out;
354 		}
355 
356 		/*
357 		 * If we're on a child clock and it provides no mapping of its
358 		 * own, inherit the mapping from its root clock.
359 		 */
360 		clkp = lookup_root_clock(clk);
361 		mapping = clkp->mapping;
362 		BUG_ON(!mapping);
363 	}
364 
365 	/*
366 	 * Establish initial mapping.
367 	 */
368 	if (!mapping->base && mapping->phys) {
369 		kref_init(&mapping->ref);
370 
371 		mapping->base = ioremap(mapping->phys, mapping->len);
372 		if (unlikely(!mapping->base))
373 			return -ENXIO;
374 	} else if (mapping->base) {
375 		/*
376 		 * Bump the refcount for an existing mapping
377 		 */
378 		kref_get(&mapping->ref);
379 	}
380 
381 	clk->mapping = mapping;
382 out:
383 	clk->mapped_reg = clk->mapping->base;
384 	clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
385 	return 0;
386 }
387 
clk_destroy_mapping(struct kref * kref)388 static void clk_destroy_mapping(struct kref *kref)
389 {
390 	struct clk_mapping *mapping;
391 
392 	mapping = container_of(kref, struct clk_mapping, ref);
393 
394 	iounmap(mapping->base);
395 }
396 
clk_teardown_mapping(struct clk * clk)397 static void clk_teardown_mapping(struct clk *clk)
398 {
399 	struct clk_mapping *mapping = clk->mapping;
400 
401 	/* Nothing to do */
402 	if (mapping == &dummy_mapping)
403 		goto out;
404 
405 	kref_put(&mapping->ref, clk_destroy_mapping);
406 	clk->mapping = NULL;
407 out:
408 	clk->mapped_reg = NULL;
409 }
410 
clk_register(struct clk * clk)411 int clk_register(struct clk *clk)
412 {
413 	int ret;
414 
415 	if (IS_ERR_OR_NULL(clk))
416 		return -EINVAL;
417 
418 	/*
419 	 * trap out already registered clocks
420 	 */
421 	if (clk->node.next || clk->node.prev)
422 		return 0;
423 
424 	mutex_lock(&clock_list_sem);
425 
426 	INIT_LIST_HEAD(&clk->children);
427 	clk->usecount = 0;
428 
429 	ret = clk_establish_mapping(clk);
430 	if (unlikely(ret))
431 		goto out_unlock;
432 
433 	if (clk->parent)
434 		list_add(&clk->sibling, &clk->parent->children);
435 	else
436 		list_add(&clk->sibling, &root_clks);
437 
438 	list_add(&clk->node, &clock_list);
439 
440 #ifdef CONFIG_SH_CLK_CPG_LEGACY
441 	if (clk->ops && clk->ops->init)
442 		clk->ops->init(clk);
443 #endif
444 
445 out_unlock:
446 	mutex_unlock(&clock_list_sem);
447 
448 	return ret;
449 }
450 EXPORT_SYMBOL_GPL(clk_register);
451 
clk_unregister(struct clk * clk)452 void clk_unregister(struct clk *clk)
453 {
454 	mutex_lock(&clock_list_sem);
455 	list_del(&clk->sibling);
456 	list_del(&clk->node);
457 	clk_teardown_mapping(clk);
458 	mutex_unlock(&clock_list_sem);
459 }
460 EXPORT_SYMBOL_GPL(clk_unregister);
461 
clk_enable_init_clocks(void)462 void clk_enable_init_clocks(void)
463 {
464 	struct clk *clkp;
465 
466 	list_for_each_entry(clkp, &clock_list, node)
467 		if (clkp->flags & CLK_ENABLE_ON_INIT)
468 			clk_enable(clkp);
469 }
470 
clk_get_rate(struct clk * clk)471 unsigned long clk_get_rate(struct clk *clk)
472 {
473 	if (!clk)
474 		return 0;
475 
476 	return clk->rate;
477 }
478 EXPORT_SYMBOL_GPL(clk_get_rate);
479 
clk_set_rate(struct clk * clk,unsigned long rate)480 int clk_set_rate(struct clk *clk, unsigned long rate)
481 {
482 	int ret = -EOPNOTSUPP;
483 	unsigned long flags;
484 
485 	if (!clk)
486 		return 0;
487 
488 	spin_lock_irqsave(&clock_lock, flags);
489 
490 	if (likely(clk->ops && clk->ops->set_rate)) {
491 		ret = clk->ops->set_rate(clk, rate);
492 		if (ret != 0)
493 			goto out_unlock;
494 	} else {
495 		clk->rate = rate;
496 		ret = 0;
497 	}
498 
499 	if (clk->ops && clk->ops->recalc)
500 		clk->rate = clk->ops->recalc(clk);
501 
502 	propagate_rate(clk);
503 
504 out_unlock:
505 	spin_unlock_irqrestore(&clock_lock, flags);
506 
507 	return ret;
508 }
509 EXPORT_SYMBOL_GPL(clk_set_rate);
510 
clk_set_parent(struct clk * clk,struct clk * parent)511 int clk_set_parent(struct clk *clk, struct clk *parent)
512 {
513 	unsigned long flags;
514 	int ret = -EINVAL;
515 
516 	if (!parent || !clk)
517 		return ret;
518 	if (clk->parent == parent)
519 		return 0;
520 
521 	spin_lock_irqsave(&clock_lock, flags);
522 	if (clk->usecount == 0) {
523 		if (clk->ops->set_parent)
524 			ret = clk->ops->set_parent(clk, parent);
525 		else
526 			ret = clk_reparent(clk, parent);
527 
528 		if (ret == 0) {
529 			if (clk->ops->recalc)
530 				clk->rate = clk->ops->recalc(clk);
531 			pr_debug("set parent of %p to %p (new rate %ld)\n",
532 				 clk, clk->parent, clk->rate);
533 			propagate_rate(clk);
534 		}
535 	} else
536 		ret = -EBUSY;
537 	spin_unlock_irqrestore(&clock_lock, flags);
538 
539 	return ret;
540 }
541 EXPORT_SYMBOL_GPL(clk_set_parent);
542 
clk_get_parent(struct clk * clk)543 struct clk *clk_get_parent(struct clk *clk)
544 {
545 	if (!clk)
546 		return NULL;
547 
548 	return clk->parent;
549 }
550 EXPORT_SYMBOL_GPL(clk_get_parent);
551 
clk_round_rate(struct clk * clk,unsigned long rate)552 long clk_round_rate(struct clk *clk, unsigned long rate)
553 {
554 	if (!clk)
555 		return 0;
556 
557 	if (likely(clk->ops && clk->ops->round_rate)) {
558 		unsigned long flags, rounded;
559 
560 		spin_lock_irqsave(&clock_lock, flags);
561 		rounded = clk->ops->round_rate(clk, rate);
562 		spin_unlock_irqrestore(&clock_lock, flags);
563 
564 		return rounded;
565 	}
566 
567 	return clk_get_rate(clk);
568 }
569 EXPORT_SYMBOL_GPL(clk_round_rate);
570 
571 #ifdef CONFIG_PM
clks_core_resume(void)572 static void clks_core_resume(void)
573 {
574 	struct clk *clkp;
575 
576 	list_for_each_entry(clkp, &clock_list, node) {
577 		if (likely(clkp->usecount && clkp->ops)) {
578 			unsigned long rate = clkp->rate;
579 
580 			if (likely(clkp->ops->set_parent))
581 				clkp->ops->set_parent(clkp,
582 					clkp->parent);
583 			if (likely(clkp->ops->set_rate))
584 				clkp->ops->set_rate(clkp, rate);
585 			else if (likely(clkp->ops->recalc))
586 				clkp->rate = clkp->ops->recalc(clkp);
587 		}
588 	}
589 }
590 
591 static struct syscore_ops clks_syscore_ops = {
592 	.resume = clks_core_resume,
593 };
594 
clk_syscore_init(void)595 static int __init clk_syscore_init(void)
596 {
597 	register_syscore_ops(&clks_syscore_ops);
598 
599 	return 0;
600 }
601 subsys_initcall(clk_syscore_init);
602 #endif
603 
clk_late_init(void)604 static int __init clk_late_init(void)
605 {
606 	unsigned long flags;
607 	struct clk *clk;
608 
609 	/* disable all clocks with zero use count */
610 	mutex_lock(&clock_list_sem);
611 	spin_lock_irqsave(&clock_lock, flags);
612 
613 	list_for_each_entry(clk, &clock_list, node)
614 		if (!clk->usecount && clk->ops && clk->ops->disable)
615 			clk->ops->disable(clk);
616 
617 	/* from now on allow clock disable operations */
618 	allow_disable = 1;
619 
620 	spin_unlock_irqrestore(&clock_lock, flags);
621 	mutex_unlock(&clock_list_sem);
622 	return 0;
623 }
624 late_initcall(clk_late_init);
625