d6702e57d4285d150b2a94b6b94a6caf60652bc1
[linux-2.6.git] / drivers / sh / clk / core.c
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;
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         debugfs_remove_recursive(c->dentry);
703         return err;
704 }
705
706 static int clk_debugfs_register(struct clk *c)
707 {
708         int err;
709         struct clk *pa = c->parent;
710
711         if (pa && !pa->dentry) {
712                 err = clk_debugfs_register(pa);
713                 if (err)
714                         return err;
715         }
716
717         if (!c->dentry) {
718                 err = clk_debugfs_register_one(c);
719                 if (err)
720                         return err;
721         }
722         return 0;
723 }
724
725 static int __init clk_debugfs_init(void)
726 {
727         struct clk *c;
728         struct dentry *d;
729         int err;
730
731         d = debugfs_create_dir("clock", NULL);
732         if (!d)
733                 return -ENOMEM;
734         clk_debugfs_root = d;
735
736         list_for_each_entry(c, &clock_list, node) {
737                 err = clk_debugfs_register(c);
738                 if (err)
739                         goto err_out;
740         }
741         return 0;
742 err_out:
743         debugfs_remove_recursive(clk_debugfs_root);
744         return err;
745 }
746 late_initcall(clk_debugfs_init);