aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/sh/clk/core.c
blob: dc8d022c07a1505b2cc0bd86ccfb2e097c6f1f16 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
/*
 * SuperH clock framework
 *
 *  Copyright (C) 2005 - 2010  Paul Mundt
 *
 * This clock framework is derived from the OMAP version by:
 *
 *	Copyright (C) 2004 - 2008 Nokia Corporation
 *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
 *
 *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#define pr_fmt(fmt) "clock: " fmt

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/syscore_ops.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/debugfs.h>
#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/sh_clk.h>

static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);

/* clock disable operations are not passed on to hardware during boot */
static int allow_disable;

void 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)
{
	unsigned long mult, div;
	unsigned long freq;
	int i;

	clk->nr_freqs = nr_freqs;

	for (i = 0; i < nr_freqs; i++) {
		div = 1;
		mult = 1;

		if (src_table->divisors && i < src_table->nr_divisors)
			div = src_table->divisors[i];

		if (src_table->multipliers && i < src_table->nr_multipliers)
			mult = src_table->multipliers[i];

		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
			freq = CPUFREQ_ENTRY_INVALID;
		else
			freq = clk->parent->rate * mult / div;

		freq_table[i].index = i;
		freq_table[i].frequency = freq;
	}

	/* Termination entry */
	freq_table[i].index = i;
	freq_table[i].frequency = CPUFREQ_TABLE_END;
}

struct clk_rate_round_data;

struct clk_rate_round_data {
	unsigned long rate;
	unsigned int min, max;
	long (*func)(unsigned int, struct clk_rate_round_data *);
	void *arg;
};

#define for_each_frequency(pos, r, freq)			\
	for (pos = r->min, freq = r->func(pos, r);		\
	     pos <= r->max; pos++, freq = r->func(pos, r))	\
		if (unlikely(freq == 0))			\
			;					\
		else

static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
{
	unsigned long rate_error, rate_error_prev = ~0UL;
	unsigned long highest, lowest, freq;
	long rate_best_fit = -ENOENT;
	int i;

	highest = 0;
	lowest = ~0UL;

	for_each_frequency(i, rounder, freq) {
		if (freq > highest)
			highest = freq;
		if (freq < lowest)
			lowest = freq;

		rate_error = abs(freq - rounder->rate);
		if (rate_error < rate_error_prev) {
			rate_best_fit = freq;
			rate_error_prev = rate_error;
		}

		if (rate_error == 0)
			break;
	}

	if (rounder->rate >= highest)
		rate_best_fit = highest;
	if (rounder->rate <= lowest)
		rate_best_fit = lowest;

	return rate_best_fit;
}

static long clk_rate_table_iter(unsigned int pos,
				struct clk_rate_round_data *rounder)
{
	struct cpufreq_frequency_table *freq_table = rounder->arg;
	unsigned long freq = freq_table[pos].frequency;

	if (freq == CPUFREQ_ENTRY_INVALID)
		freq = 0;

	return freq;
}

long clk_rate_table_round(struct clk *clk,
			  struct cpufreq_frequency_table *freq_table,
			  unsigned long rate)
{
	struct clk_rate_round_data table_round = {
		.min	= 0,
		.max	= clk->nr_freqs - 1,
		.func	= clk_rate_table_iter,
		.arg	= freq_table,
		.rate	= rate,
	};

	if (clk->nr_freqs < 1)
		return -ENOSYS;

	return clk_rate_round_helper(&table_round);
}

static long clk_rate_div_range_iter(unsigned int pos,
				    struct clk_rate_round_data *rounder)
{
	return clk_get_rate(rounder->arg) / pos;
}

long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
			      unsigned int div_max, unsigned long rate)
{
	struct clk_rate_round_data div_range_round = {
		.min	= div_min,
		.max	= div_max,
		.func	= clk_rate_div_range_iter,
		.arg	= clk_get_parent(clk),
		.rate	= rate,
	};

	return clk_rate_round_helper(&div_range_round);
}

int clk_rate_table_find(struct clk *clk,
			struct cpufreq_frequency_table *freq_table,
			unsigned long rate)
{
	int i;

	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
		unsigned long freq = freq_table[i].frequency;

		if (freq == CPUFREQ_ENTRY_INVALID)
			continue;

		if (freq == rate)
			return i;
	}

	return -ENOENT;
}

/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{
	return clk->parent ? clk->parent->rate : 0;
}

int clk_reparent(struct clk *child, struct clk *parent)
{
	list_del_init(&child->sibling);
	if (parent)
		list_add(&child->sibling, &parent->children);
	child->parent = parent;

	/* now do the debugfs renaming to reattach the child
	   to the proper parent */

	return 0;
}

/* Propagate rate to children */
void propagate_rate(struct clk *tclk)
{
	struct clk *clkp;

	list_for_each_entry(clkp, &tclk->children, sibling) {
		if (clkp->ops && clkp->ops->recalc)
			clkp->rate = clkp->ops->recalc(clkp);

		propagate_rate(clkp);
	}
}

static void __clk_disable(struct clk *clk)
{
	if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
		 clk))
		return;

	if (!(--clk->usecount)) {
		if (likely(allow_disable && clk->ops && clk->ops->disable))
			clk->ops->disable(clk);
		if (likely(clk->parent))
			__clk_disable(clk->parent);
	}
}

void clk_disable(struct clk *clk)
{
	unsigned long flags;

	if (!clk)
		return;

	spin_lock_irqsave(&clock_lock, flags);
	__clk_disable(clk);
	spin_unlock_irqrestore(&clock_lock, flags);
}
EXPORT_SYMBOL_GPL(clk_disable);

static int __clk_enable(struct clk *clk)
{
	int ret = 0;

	if (clk->usecount++ == 0) {
		if (clk->parent) {
			ret = __clk_enable(clk->parent);
			if (unlikely(ret))
				goto err;
		}

		if (clk->ops && clk->ops->enable) {
			ret = clk->ops->enable(clk);
			if (ret) {
				if (clk->parent)
					__clk_disable(clk->parent);
				goto err;
			}
		}
	}

	return ret;
err:
	clk->usecount--;
	return ret;
}

int clk_enable(struct clk *clk)
{
	unsigned long flags;
	int ret;

	if (!clk)
		return -EINVAL;

	spin_lock_irqsave(&clock_lock, flags);
	ret = __clk_enable(clk);
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
}
EXPORT_SYMBOL_GPL(clk_enable);

static LIST_HEAD(root_clks);

/**
 * recalculate_root_clocks - recalculate and propagate all root clocks
 *
 * Recalculates all root clocks (clocks with no parent), which if the
 * clock's .recalc is set correctly, should also propagate their rates.
 * Called at init.
 */
void recalculate_root_clocks(void)
{
	struct clk *clkp;

	list_for_each_entry(clkp, &root_clks, sibling) {
		if (clkp->ops && clkp->ops->recalc)
			clkp->rate = clkp->ops->recalc(clkp);
		propagate_rate(clkp);
	}
}

static struct clk_mapping dummy_mapping;

static struct clk *lookup_root_clock(struct clk *clk)
{
	while (clk->parent)
		clk = clk->parent;

	return clk;
}

static int clk_establish_mapping(struct clk *clk)
{
	struct clk_mapping *mapping = clk->mapping;

	/*
	 * Propagate mappings.
	 */
	if (!mapping) {
		struct clk *clkp;

		/*
		 * dummy mapping for root clocks with no specified ranges
		 */
		if (!clk->parent) {
			clk->mapping = &dummy_mapping;
			return 0;
		}

		/*
		 * If we're on a child clock and it provides no mapping of its
		 * own, inherit the mapping from its root clock.
		 */
		clkp = lookup_root_clock(clk);
		mapping = clkp->mapping;
		BUG_ON(!mapping);
	}

	/*
	 * Establish initial mapping.
	 */
	if (!mapping->base && mapping->phys) {
		kref_init(&mapping->ref);

		mapping->base = ioremap_nocache(mapping->phys, mapping->len);
		if (unlikely(!mapping->base))
			return -ENXIO;
	} else if (mapping->base) {
		/*
		 * Bump the refcount for an existing mapping
		 */
		kref_get(&mapping->ref);
	}

	clk->mapping = mapping;
	return 0;
}

static void clk_destroy_mapping(struct kref *kref)
{
	struct clk_mapping *mapping;

	mapping = container_of(kref, struct clk_mapping, ref);

	iounmap(mapping->base);
}

static void clk_teardown_mapping(struct clk *clk)
{
	struct clk_mapping *mapping = clk->mapping;

	/* Nothing to do */
	if (mapping == &dummy_mapping)
		return;

	kref_put(&mapping->ref, clk_destroy_mapping);
	clk->mapping = NULL;
}

int clk_register(struct clk *clk)
{
	int ret;

	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	/*
	 * trap out already registered clocks
	 */
	if (clk->node.next || clk->node.prev)
		return 0;

	mutex_lock(&clock_list_sem);

	INIT_LIST_HEAD(&clk->children);
	clk->usecount = 0;

	ret = clk_establish_mapping(clk);
	if (unlikely(ret))
		goto out_unlock;

	if (clk->parent)
		list_add(&clk->sibling, &clk->parent->children);
	else
		list_add(&clk->sibling, &root_clks);

	list_add(&clk->node, &clock_list);

#ifdef CONFIG_SH_CLK_CPG_LEGACY
	if (clk->ops && clk->ops->init)
		clk->ops->init(clk);
#endif

out_unlock:
	mutex_unlock(&clock_list_sem);

	return ret;
}
EXPORT_SYMBOL_GPL(clk_register);

void clk_unregister(struct clk *clk)
{
	mutex_lock(&clock_list_sem);
	list_del(&clk->sibling);
	list_del(&clk->node);
	clk_teardown_mapping(clk);
	mutex_unlock(&clock_list_sem);
}
EXPORT_SYMBOL_GPL(clk_unregister);

void clk_enable_init_clocks(void)
{
	struct clk *clkp;

	list_for_each_entry(clkp, &clock_list, node)
		if (clkp->flags & CLK_ENABLE_ON_INIT)
			clk_enable(clkp);
}

unsigned long clk_get_rate(struct clk *clk)
{
	return clk->rate;
}
EXPORT_SYMBOL_GPL(clk_get_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
	int ret = -EOPNOTSUPP;
	unsigned long flags;

	spin_lock_irqsave(&clock_lock, flags);

	if (likely(clk->ops && clk->ops->set_rate)) {
		ret = clk->ops->set_rate(clk, rate);
		if (ret != 0)
			goto out_unlock;
	} else {
		clk->rate = rate;
		ret = 0;
	}

	if (clk->ops && clk->ops->recalc)
		clk->rate = clk->ops->recalc(clk);

	propagate_rate(clk);

out_unlock:
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate);

int clk_set_parent(struct clk *clk, struct clk *parent)
{
	unsigned long flags;
	int ret = -EINVAL;

	if (!parent || !clk)
		return ret;
	if (clk->parent == parent)
		return 0;

	spin_lock_irqsave(&clock_lock, flags);
	if (clk->usecount == 0) {
		if (clk->ops->set_parent)
			ret = clk->ops->set_parent(clk, parent);
		else
			ret = clk_reparent(clk, parent);

		if (ret == 0) {
			if (clk->ops->recalc)
				clk->rate = clk->ops->recalc(clk);
			pr_debug("set parent of %p to %p (new rate %ld)\n",
				 clk, clk->parent, clk->rate);
			propagate_rate(clk);
		}
	} else
		ret = -EBUSY;
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);

struct clk *clk_get_parent(struct clk *clk)
{
	return clk->parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
	if (likely(clk->ops && clk->ops->round_rate)) {
		unsigned long flags, rounded;

		spin_lock_irqsave(&clock_lock, flags);
		rounded = clk->ops->round_rate(clk, rate);
		spin_unlock_irqrestore(&clock_lock, flags);

		return rounded;
	}

	return clk_get_rate(clk);
}
EXPORT_SYMBOL_GPL(clk_round_rate);

long clk_round_parent(struct clk *clk, unsigned long target,
		      unsigned long *best_freq, unsigned long *parent_freq,
		      unsigned int div_min, unsigned int div_max)
{
	struct cpufreq_frequency_table *freq, *best = NULL;
	unsigned long error = ULONG_MAX, freq_high, freq_low, div;
	struct clk *parent = clk_get_parent(clk);

	if (!parent) {
		*parent_freq = 0;
		*best_freq = clk_round_rate(clk, target);
		return abs(target - *best_freq);
	}

	for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
	     freq++) {
		if (freq->frequency == CPUFREQ_ENTRY_INVALID)
			continue;

		if (unlikely(freq->frequency / target <= div_min - 1)) {
			unsigned long freq_max;

			freq_max = (freq->frequency + div_min / 2) / div_min;
			if (error > target - freq_max) {
				error = target - freq_max;
				best = freq;
				if (best_freq)
					*best_freq = freq_max;
			}

			pr_debug("too low freq %u, error %lu\n", freq->frequency,
				 target - freq_max);

			if (!error)
				break;

			continue;
		}

		if (unlikely(freq->frequency / target >= div_max)) {
			unsigned long freq_min;

			freq_min = (freq->frequency + div_max / 2) / div_max;
			if (error > freq_min - target) {
				error = freq_min - target;
				best = freq;
				if (best_freq)
					*best_freq = freq_min;
			}

			pr_debug("too high freq %u, error %lu\n", freq->frequency,
				 freq_min - target);

			if (!error)
				break;

			continue;
		}

		div = freq->frequency / target;
		freq_high = freq->frequency / div;
		freq_low = freq->frequency / (div + 1);

		if (freq_high - target < error) {
			error = freq_high - target;
			best = freq;
			if (best_freq)
				*best_freq = freq_high;
		}

		if (target - freq_low < error) {
			error = target - freq_low;
			best = freq;
			if (best_freq)
				*best_freq = freq_low;
		}

		pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
			 freq->frequency, div, freq_high, div + 1, freq_low,
			 *best_freq, best->frequency);

		if (!error)
			break;
	}

	if (parent_freq)
		*parent_freq = best->frequency;

	return error;
}
EXPORT_SYMBOL_GPL(clk_round_parent);

#ifdef CONFIG_PM
static void clks_core_resume(void)
{
	struct clk *clkp;

	list_for_each_entry(clkp, &clock_list, node) {
		if (likely(clkp->usecount && clkp->ops)) {
			unsigned long rate = clkp->rate;

			if (likely(clkp->ops->set_parent))
				clkp->ops->set_parent(clkp,
					clkp->parent);
			if (likely(clkp->ops->set_rate))
				clkp->ops->set_rate(clkp, rate);
			else if (likely(clkp->ops->recalc))
				clkp->rate = clkp->ops->recalc(clkp);
		}
	}
}

static struct syscore_ops clks_syscore_ops = {
	.resume = clks_core_resume,
};

static int __init clk_syscore_init(void)
{
	register_syscore_ops(&clks_syscore_ops);

	return 0;
}
subsys_initcall(clk_syscore_init);
#endif

/*
 *	debugfs support to trace clock tree hierarchy and attributes
 */
static struct dentry *clk_debugfs_root;

static int clk_debugfs_register_one(struct clk *c)
{
	int err;
	struct dentry *d;
	struct clk *pa = c->parent;
	char s[255];
	char *p = s;

	p += sprintf(p, "%p", c);
	d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
	if (!d)
		return -ENOMEM;
	c->dentry = d;

	d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
	if (!d) {
		err = -ENOMEM;
		goto err_out;
	}
	d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
	if (!d) {
		err = -ENOMEM;
		goto err_out;
	}
	d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
	if (!d) {
		err = -ENOMEM;
		goto err_out;
	}
	return 0;

err_out:
	debugfs_remove_recursive(c->dentry);
	return err;
}

static int clk_debugfs_register(struct clk *c)
{
	int err;
	struct clk *pa = c->parent;

	if (pa && !pa->dentry) {
		err = clk_debugfs_register(pa);
		if (err)
			return err;
	}

	if (!c->dentry) {
		err = clk_debugfs_register_one(c);
		if (err)
			return err;
	}
	return 0;
}

static int __init clk_debugfs_init(void)
{
	struct clk *c;
	struct dentry *d;
	int err;

	d = debugfs_create_dir("clock", NULL);
	if (!d)
		return -ENOMEM;
	clk_debugfs_root = d;

	list_for_each_entry(c, &clock_list, node) {
		err = clk_debugfs_register(c);
		if (err)
			goto err_out;
	}
	return 0;
err_out:
	debugfs_remove_recursive(clk_debugfs_root);
	return err;
}
late_initcall(clk_debugfs_init);

static int __init clk_late_init(void)
{
	unsigned long flags;
	struct clk *clk;

	/* disable all clocks with zero use count */
	mutex_lock(&clock_list_sem);
	spin_lock_irqsave(&clock_lock, flags);

	list_for_each_entry(clk, &clock_list, node)
		if (!clk->usecount && clk->ops && clk->ops->disable)
			clk->ops->disable(clk);

	/* from now on allow clock disable operations */
	allow_disable = 1;

	spin_unlock_irqrestore(&clock_lock, flags);
	mutex_unlock(&clock_list_sem);
	return 0;
}
late_initcall(clk_late_init);