2 * SuperH clock framework
4 * Copyright (C) 2005 - 2010 Paul Mundt
6 * This clock framework is derived from the OMAP version by:
8 * Copyright (C) 2004 - 2008 Nokia Corporation
9 * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
11 * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
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
17 #define pr_fmt(fmt) "clock: " fmt
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>
28 #include <linux/debugfs.h>
29 #include <linux/cpufreq.h>
30 #include <linux/clk.h>
31 #include <linux/sh_clk.h>
33 static LIST_HEAD(clock_list);
34 static DEFINE_SPINLOCK(clock_lock);
35 static DEFINE_MUTEX(clock_list_sem);
37 /* clock disable operations are not passed on to hardware during boot */
38 static int allow_disable;
40 void clk_rate_table_build(struct clk *clk,
41 struct cpufreq_frequency_table *freq_table,
43 struct clk_div_mult_table *src_table,
44 unsigned long *bitmap)
46 unsigned long mult, div;
50 clk->nr_freqs = nr_freqs;
52 for (i = 0; i < nr_freqs; i++) {
56 if (src_table->divisors && i < src_table->nr_divisors)
57 div = src_table->divisors[i];
59 if (src_table->multipliers && i < src_table->nr_multipliers)
60 mult = src_table->multipliers[i];
62 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
63 freq = CPUFREQ_ENTRY_INVALID;
65 freq = clk->parent->rate * mult / div;
67 freq_table[i].index = i;
68 freq_table[i].frequency = freq;
71 /* Termination entry */
72 freq_table[i].index = i;
73 freq_table[i].frequency = CPUFREQ_TABLE_END;
76 struct clk_rate_round_data;
78 struct clk_rate_round_data {
80 unsigned int min, max;
81 long (*func)(unsigned int, struct clk_rate_round_data *);
85 #define for_each_frequency(pos, r, freq) \
86 for (pos = r->min, freq = r->func(pos, r); \
87 pos <= r->max; pos++, freq = r->func(pos, r)) \
88 if (unlikely(freq == 0)) \
92 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
94 unsigned long rate_error, rate_error_prev = ~0UL;
95 unsigned long highest, lowest, freq;
96 long rate_best_fit = -ENOENT;
102 for_each_frequency(i, rounder, freq) {
108 rate_error = abs(freq - rounder->rate);
109 if (rate_error < rate_error_prev) {
110 rate_best_fit = freq;
111 rate_error_prev = rate_error;
118 if (rounder->rate >= highest)
119 rate_best_fit = highest;
120 if (rounder->rate <= lowest)
121 rate_best_fit = lowest;
123 return rate_best_fit;
126 static long clk_rate_table_iter(unsigned int pos,
127 struct clk_rate_round_data *rounder)
129 struct cpufreq_frequency_table *freq_table = rounder->arg;
130 unsigned long freq = freq_table[pos].frequency;
132 if (freq == CPUFREQ_ENTRY_INVALID)
138 long clk_rate_table_round(struct clk *clk,
139 struct cpufreq_frequency_table *freq_table,
142 struct clk_rate_round_data table_round = {
144 .max = clk->nr_freqs - 1,
145 .func = clk_rate_table_iter,
150 if (clk->nr_freqs < 1)
153 return clk_rate_round_helper(&table_round);
156 static long clk_rate_div_range_iter(unsigned int pos,
157 struct clk_rate_round_data *rounder)
159 return clk_get_rate(rounder->arg) / pos;
162 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
163 unsigned int div_max, unsigned long rate)
165 struct clk_rate_round_data div_range_round = {
168 .func = clk_rate_div_range_iter,
169 .arg = clk_get_parent(clk),
173 return clk_rate_round_helper(&div_range_round);
176 int clk_rate_table_find(struct clk *clk,
177 struct cpufreq_frequency_table *freq_table,
182 for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
183 unsigned long freq = freq_table[i].frequency;
185 if (freq == CPUFREQ_ENTRY_INVALID)
195 /* Used for clocks that always have same value as the parent clock */
196 unsigned long followparent_recalc(struct clk *clk)
198 return clk->parent ? clk->parent->rate : 0;
201 int clk_reparent(struct clk *child, struct clk *parent)
203 list_del_init(&child->sibling);
205 list_add(&child->sibling, &parent->children);
206 child->parent = parent;
208 /* now do the debugfs renaming to reattach the child
209 to the proper parent */
214 /* Propagate rate to children */
215 void propagate_rate(struct clk *tclk)
219 list_for_each_entry(clkp, &tclk->children, sibling) {
220 if (clkp->ops && clkp->ops->recalc)
221 clkp->rate = clkp->ops->recalc(clkp);
223 propagate_rate(clkp);
227 static void __clk_disable(struct clk *clk)
229 if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
233 if (!(--clk->usecount)) {
234 if (likely(allow_disable && clk->ops && clk->ops->disable))
235 clk->ops->disable(clk);
236 if (likely(clk->parent))
237 __clk_disable(clk->parent);
241 void clk_disable(struct clk *clk)
248 spin_lock_irqsave(&clock_lock, flags);
250 spin_unlock_irqrestore(&clock_lock, flags);
252 EXPORT_SYMBOL_GPL(clk_disable);
254 static int __clk_enable(struct clk *clk)
258 if (clk->usecount++ == 0) {
260 ret = __clk_enable(clk->parent);
265 if (clk->ops && clk->ops->enable) {
266 ret = clk->ops->enable(clk);
269 __clk_disable(clk->parent);
281 int clk_enable(struct clk *clk)
289 spin_lock_irqsave(&clock_lock, flags);
290 ret = __clk_enable(clk);
291 spin_unlock_irqrestore(&clock_lock, flags);
295 EXPORT_SYMBOL_GPL(clk_enable);
297 static LIST_HEAD(root_clks);
300 * recalculate_root_clocks - recalculate and propagate all root clocks
302 * Recalculates all root clocks (clocks with no parent), which if the
303 * clock's .recalc is set correctly, should also propagate their rates.
306 void recalculate_root_clocks(void)
310 list_for_each_entry(clkp, &root_clks, sibling) {
311 if (clkp->ops && clkp->ops->recalc)
312 clkp->rate = clkp->ops->recalc(clkp);
313 propagate_rate(clkp);
317 static struct clk_mapping dummy_mapping;
319 static struct clk *lookup_root_clock(struct clk *clk)
327 static int clk_establish_mapping(struct clk *clk)
329 struct clk_mapping *mapping = clk->mapping;
332 * Propagate mappings.
338 * dummy mapping for root clocks with no specified ranges
341 clk->mapping = &dummy_mapping;
346 * If we're on a child clock and it provides no mapping of its
347 * own, inherit the mapping from its root clock.
349 clkp = lookup_root_clock(clk);
350 mapping = clkp->mapping;
355 * Establish initial mapping.
357 if (!mapping->base && mapping->phys) {
358 kref_init(&mapping->ref);
360 mapping->base = ioremap_nocache(mapping->phys, mapping->len);
361 if (unlikely(!mapping->base))
363 } else if (mapping->base) {
365 * Bump the refcount for an existing mapping
367 kref_get(&mapping->ref);
370 clk->mapping = mapping;
374 static void clk_destroy_mapping(struct kref *kref)
376 struct clk_mapping *mapping;
378 mapping = container_of(kref, struct clk_mapping, ref);
380 iounmap(mapping->base);
383 static void clk_teardown_mapping(struct clk *clk)
385 struct clk_mapping *mapping = clk->mapping;
388 if (mapping == &dummy_mapping)
391 kref_put(&mapping->ref, clk_destroy_mapping);
395 int clk_register(struct clk *clk)
399 if (IS_ERR_OR_NULL(clk))
403 * trap out already registered clocks
405 if (clk->node.next || clk->node.prev)
408 mutex_lock(&clock_list_sem);
410 INIT_LIST_HEAD(&clk->children);
413 ret = clk_establish_mapping(clk);
418 list_add(&clk->sibling, &clk->parent->children);
420 list_add(&clk->sibling, &root_clks);
422 list_add(&clk->node, &clock_list);
424 #ifdef CONFIG_SH_CLK_CPG_LEGACY
425 if (clk->ops && clk->ops->init)
430 mutex_unlock(&clock_list_sem);
434 EXPORT_SYMBOL_GPL(clk_register);
436 void clk_unregister(struct clk *clk)
438 mutex_lock(&clock_list_sem);
439 list_del(&clk->sibling);
440 list_del(&clk->node);
441 clk_teardown_mapping(clk);
442 mutex_unlock(&clock_list_sem);
444 EXPORT_SYMBOL_GPL(clk_unregister);
446 void clk_enable_init_clocks(void)
450 list_for_each_entry(clkp, &clock_list, node)
451 if (clkp->flags & CLK_ENABLE_ON_INIT)
455 unsigned long clk_get_rate(struct clk *clk)
459 EXPORT_SYMBOL_GPL(clk_get_rate);
461 int clk_set_rate(struct clk *clk, unsigned long rate)
463 int ret = -EOPNOTSUPP;
466 spin_lock_irqsave(&clock_lock, flags);
468 if (likely(clk->ops && clk->ops->set_rate)) {
469 ret = clk->ops->set_rate(clk, rate);
477 if (clk->ops && clk->ops->recalc)
478 clk->rate = clk->ops->recalc(clk);
483 spin_unlock_irqrestore(&clock_lock, flags);
487 EXPORT_SYMBOL_GPL(clk_set_rate);
489 int clk_set_parent(struct clk *clk, struct clk *parent)
496 if (clk->parent == parent)
499 spin_lock_irqsave(&clock_lock, flags);
500 if (clk->usecount == 0) {
501 if (clk->ops->set_parent)
502 ret = clk->ops->set_parent(clk, parent);
504 ret = clk_reparent(clk, parent);
507 if (clk->ops->recalc)
508 clk->rate = clk->ops->recalc(clk);
509 pr_debug("set parent of %p to %p (new rate %ld)\n",
510 clk, clk->parent, clk->rate);
515 spin_unlock_irqrestore(&clock_lock, flags);
519 EXPORT_SYMBOL_GPL(clk_set_parent);
521 struct clk *clk_get_parent(struct clk *clk)
525 EXPORT_SYMBOL_GPL(clk_get_parent);
527 long clk_round_rate(struct clk *clk, unsigned long rate)
529 if (likely(clk->ops && clk->ops->round_rate)) {
530 unsigned long flags, rounded;
532 spin_lock_irqsave(&clock_lock, flags);
533 rounded = clk->ops->round_rate(clk, rate);
534 spin_unlock_irqrestore(&clock_lock, flags);
539 return clk_get_rate(clk);
541 EXPORT_SYMBOL_GPL(clk_round_rate);
543 long clk_round_parent(struct clk *clk, unsigned long target,
544 unsigned long *best_freq, unsigned long *parent_freq,
545 unsigned int div_min, unsigned int div_max)
547 struct cpufreq_frequency_table *freq, *best = NULL;
548 unsigned long error = ULONG_MAX, freq_high, freq_low, div;
549 struct clk *parent = clk_get_parent(clk);
553 *best_freq = clk_round_rate(clk, target);
554 return abs(target - *best_freq);
557 for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
559 if (freq->frequency == CPUFREQ_ENTRY_INVALID)
562 if (unlikely(freq->frequency / target <= div_min - 1)) {
563 unsigned long freq_max;
565 freq_max = (freq->frequency + div_min / 2) / div_min;
566 if (error > target - freq_max) {
567 error = target - freq_max;
570 *best_freq = freq_max;
573 pr_debug("too low freq %u, error %lu\n", freq->frequency,
582 if (unlikely(freq->frequency / target >= div_max)) {
583 unsigned long freq_min;
585 freq_min = (freq->frequency + div_max / 2) / div_max;
586 if (error > freq_min - target) {
587 error = freq_min - target;
590 *best_freq = freq_min;
593 pr_debug("too high freq %u, error %lu\n", freq->frequency,
602 div = freq->frequency / target;
603 freq_high = freq->frequency / div;
604 freq_low = freq->frequency / (div + 1);
606 if (freq_high - target < error) {
607 error = freq_high - target;
610 *best_freq = freq_high;
613 if (target - freq_low < error) {
614 error = target - freq_low;
617 *best_freq = freq_low;
620 pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
621 freq->frequency, div, freq_high, div + 1, freq_low,
622 *best_freq, best->frequency);
629 *parent_freq = best->frequency;
633 EXPORT_SYMBOL_GPL(clk_round_parent);
636 static void clks_core_resume(void)
640 list_for_each_entry(clkp, &clock_list, node) {
641 if (likely(clkp->usecount && clkp->ops)) {
642 unsigned long rate = clkp->rate;
644 if (likely(clkp->ops->set_parent))
645 clkp->ops->set_parent(clkp,
647 if (likely(clkp->ops->set_rate))
648 clkp->ops->set_rate(clkp, rate);
649 else if (likely(clkp->ops->recalc))
650 clkp->rate = clkp->ops->recalc(clkp);
655 static struct syscore_ops clks_syscore_ops = {
656 .resume = clks_core_resume,
659 static int __init clk_syscore_init(void)
661 register_syscore_ops(&clks_syscore_ops);
665 subsys_initcall(clk_syscore_init);
669 * debugfs support to trace clock tree hierarchy and attributes
671 static struct dentry *clk_debugfs_root;
673 static int clk_debugfs_register_one(struct clk *c)
677 struct clk *pa = c->parent;
681 p += sprintf(p, "%p", c);
682 d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
687 d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
692 d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
697 d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
705 debugfs_remove_recursive(c->dentry);
709 static int clk_debugfs_register(struct clk *c)
712 struct clk *pa = c->parent;
714 if (pa && !pa->dentry) {
715 err = clk_debugfs_register(pa);
721 err = clk_debugfs_register_one(c);
728 static int __init clk_debugfs_init(void)
734 d = debugfs_create_dir("clock", NULL);
737 clk_debugfs_root = d;
739 list_for_each_entry(c, &clock_list, node) {
740 err = clk_debugfs_register(c);
746 debugfs_remove_recursive(clk_debugfs_root);
749 late_initcall(clk_debugfs_init);
751 static int __init clk_late_init(void)
756 /* disable all clocks with zero use count */
757 mutex_lock(&clock_list_sem);
758 spin_lock_irqsave(&clock_lock, flags);
760 list_for_each_entry(clk, &clock_list, node)
761 if (!clk->usecount && clk->ops && clk->ops->disable)
762 clk->ops->disable(clk);
764 /* from now on allow clock disable operations */
767 spin_unlock_irqrestore(&clock_lock, flags);
768 mutex_unlock(&clock_list_sem);
771 late_initcall(clk_late_init);