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Linux/arch/sh/kernel/cpu/clock.c

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  1 /*
  2  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
  3  *
  4  *  Copyright (C) 2005 - 2009  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  *  With clkdev bits:
 14  *
 15  *      Copyright (C) 2008 Russell King.
 16  *
 17  * This file is subject to the terms and conditions of the GNU General Public
 18  * License.  See the file "COPYING" in the main directory of this archive
 19  * for more details.
 20  */
 21 #include <linux/kernel.h>
 22 #include <linux/init.h>
 23 #include <linux/module.h>
 24 #include <linux/mutex.h>
 25 #include <linux/list.h>
 26 #include <linux/kobject.h>
 27 #include <linux/sysdev.h>
 28 #include <linux/seq_file.h>
 29 #include <linux/err.h>
 30 #include <linux/platform_device.h>
 31 #include <linux/debugfs.h>
 32 #include <linux/cpufreq.h>
 33 #include <asm/clock.h>
 34 #include <asm/machvec.h>
 35 
 36 static LIST_HEAD(clock_list);
 37 static DEFINE_SPINLOCK(clock_lock);
 38 static DEFINE_MUTEX(clock_list_sem);
 39 
 40 void clk_rate_table_build(struct clk *clk,
 41                           struct cpufreq_frequency_table *freq_table,
 42                           int nr_freqs,
 43                           struct clk_div_mult_table *src_table,
 44                           unsigned long *bitmap)
 45 {
 46         unsigned long mult, div;
 47         unsigned long freq;
 48         int i;
 49 
 50         for (i = 0; i < nr_freqs; i++) {
 51                 div = 1;
 52                 mult = 1;
 53 
 54                 if (src_table->divisors && i < src_table->nr_divisors)
 55                         div = src_table->divisors[i];
 56 
 57                 if (src_table->multipliers && i < src_table->nr_multipliers)
 58                         mult = src_table->multipliers[i];
 59 
 60                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
 61                         freq = CPUFREQ_ENTRY_INVALID;
 62                 else
 63                         freq = clk->parent->rate * mult / div;
 64 
 65                 freq_table[i].index = i;
 66                 freq_table[i].frequency = freq;
 67         }
 68 
 69         /* Termination entry */
 70         freq_table[i].index = i;
 71         freq_table[i].frequency = CPUFREQ_TABLE_END;
 72 }
 73 
 74 long clk_rate_table_round(struct clk *clk,
 75                           struct cpufreq_frequency_table *freq_table,
 76                           unsigned long rate)
 77 {
 78         unsigned long rate_error, rate_error_prev = ~0UL;
 79         unsigned long rate_best_fit = rate;
 80         unsigned long highest, lowest;
 81         int i;
 82 
 83         highest = lowest = 0;
 84 
 85         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 86                 unsigned long freq = freq_table[i].frequency;
 87 
 88                 if (freq == CPUFREQ_ENTRY_INVALID)
 89                         continue;
 90 
 91                 if (freq > highest)
 92                         highest = freq;
 93                 if (freq < lowest)
 94                         lowest = freq;
 95 
 96                 rate_error = abs(freq - rate);
 97                 if (rate_error < rate_error_prev) {
 98                         rate_best_fit = freq;
 99                         rate_error_prev = rate_error;
100                 }
101 
102                 if (rate_error == 0)
103                         break;
104         }
105 
106         if (rate >= highest)
107                 rate_best_fit = highest;
108         if (rate <= lowest)
109                 rate_best_fit = lowest;
110 
111         return rate_best_fit;
112 }
113 
114 int clk_rate_table_find(struct clk *clk,
115                         struct cpufreq_frequency_table *freq_table,
116                         unsigned long rate)
117 {
118         int i;
119 
120         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
121                 unsigned long freq = freq_table[i].frequency;
122 
123                 if (freq == CPUFREQ_ENTRY_INVALID)
124                         continue;
125 
126                 if (freq == rate)
127                         return i;
128         }
129 
130         return -ENOENT;
131 }
132 
133 /* Used for clocks that always have same value as the parent clock */
134 unsigned long followparent_recalc(struct clk *clk)
135 {
136         return clk->parent ? clk->parent->rate : 0;
137 }
138 
139 int clk_reparent(struct clk *child, struct clk *parent)
140 {
141         list_del_init(&child->sibling);
142         if (parent)
143                 list_add(&child->sibling, &parent->children);
144         child->parent = parent;
145 
146         /* now do the debugfs renaming to reattach the child
147            to the proper parent */
148 
149         return 0;
150 }
151 
152 /* Propagate rate to children */
153 void propagate_rate(struct clk *tclk)
154 {
155         struct clk *clkp;
156 
157         list_for_each_entry(clkp, &tclk->children, sibling) {
158                 if (clkp->ops && clkp->ops->recalc)
159                         clkp->rate = clkp->ops->recalc(clkp);
160 
161                 propagate_rate(clkp);
162         }
163 }
164 
165 static void __clk_disable(struct clk *clk)
166 {
167         if (clk->usecount == 0) {
168                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
169                        clk->name);
170                 WARN_ON(1);
171                 return;
172         }
173 
174         if (!(--clk->usecount)) {
175                 if (likely(clk->ops && clk->ops->disable))
176                         clk->ops->disable(clk);
177                 if (likely(clk->parent))
178                         __clk_disable(clk->parent);
179         }
180 }
181 
182 void clk_disable(struct clk *clk)
183 {
184         unsigned long flags;
185 
186         if (!clk)
187                 return;
188 
189         spin_lock_irqsave(&clock_lock, flags);
190         __clk_disable(clk);
191         spin_unlock_irqrestore(&clock_lock, flags);
192 }
193 EXPORT_SYMBOL_GPL(clk_disable);
194 
195 static int __clk_enable(struct clk *clk)
196 {
197         int ret = 0;
198 
199         if (clk->usecount++ == 0) {
200                 if (clk->parent) {
201                         ret = __clk_enable(clk->parent);
202                         if (unlikely(ret))
203                                 goto err;
204                 }
205 
206                 if (clk->ops && clk->ops->enable) {
207                         ret = clk->ops->enable(clk);
208                         if (ret) {
209                                 if (clk->parent)
210                                         __clk_disable(clk->parent);
211                                 goto err;
212                         }
213                 }
214         }
215 
216         return ret;
217 err:
218         clk->usecount--;
219         return ret;
220 }
221 
222 int clk_enable(struct clk *clk)
223 {
224         unsigned long flags;
225         int ret;
226 
227         if (!clk)
228                 return -EINVAL;
229 
230         spin_lock_irqsave(&clock_lock, flags);
231         ret = __clk_enable(clk);
232         spin_unlock_irqrestore(&clock_lock, flags);
233 
234         return ret;
235 }
236 EXPORT_SYMBOL_GPL(clk_enable);
237 
238 static LIST_HEAD(root_clks);
239 
240 /**
241  * recalculate_root_clocks - recalculate and propagate all root clocks
242  *
243  * Recalculates all root clocks (clocks with no parent), which if the
244  * clock's .recalc is set correctly, should also propagate their rates.
245  * Called at init.
246  */
247 void recalculate_root_clocks(void)
248 {
249         struct clk *clkp;
250 
251         list_for_each_entry(clkp, &root_clks, sibling) {
252                 if (clkp->ops && clkp->ops->recalc)
253                         clkp->rate = clkp->ops->recalc(clkp);
254                 propagate_rate(clkp);
255         }
256 }
257 
258 int clk_register(struct clk *clk)
259 {
260         if (clk == NULL || IS_ERR(clk))
261                 return -EINVAL;
262 
263         /*
264          * trap out already registered clocks
265          */
266         if (clk->node.next || clk->node.prev)
267                 return 0;
268 
269         mutex_lock(&clock_list_sem);
270 
271         INIT_LIST_HEAD(&clk->children);
272         clk->usecount = 0;
273 
274         if (clk->parent)
275                 list_add(&clk->sibling, &clk->parent->children);
276         else
277                 list_add(&clk->sibling, &root_clks);
278 
279         list_add(&clk->node, &clock_list);
280         if (clk->ops && clk->ops->init)
281                 clk->ops->init(clk);
282         mutex_unlock(&clock_list_sem);
283 
284         return 0;
285 }
286 EXPORT_SYMBOL_GPL(clk_register);
287 
288 void clk_unregister(struct clk *clk)
289 {
290         mutex_lock(&clock_list_sem);
291         list_del(&clk->sibling);
292         list_del(&clk->node);
293         mutex_unlock(&clock_list_sem);
294 }
295 EXPORT_SYMBOL_GPL(clk_unregister);
296 
297 static void clk_enable_init_clocks(void)
298 {
299         struct clk *clkp;
300 
301         list_for_each_entry(clkp, &clock_list, node)
302                 if (clkp->flags & CLK_ENABLE_ON_INIT)
303                         clk_enable(clkp);
304 }
305 
306 unsigned long clk_get_rate(struct clk *clk)
307 {
308         return clk->rate;
309 }
310 EXPORT_SYMBOL_GPL(clk_get_rate);
311 
312 int clk_set_rate(struct clk *clk, unsigned long rate)
313 {
314         return clk_set_rate_ex(clk, rate, 0);
315 }
316 EXPORT_SYMBOL_GPL(clk_set_rate);
317 
318 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
319 {
320         int ret = -EOPNOTSUPP;
321         unsigned long flags;
322 
323         spin_lock_irqsave(&clock_lock, flags);
324 
325         if (likely(clk->ops && clk->ops->set_rate)) {
326                 ret = clk->ops->set_rate(clk, rate, algo_id);
327                 if (ret != 0)
328                         goto out_unlock;
329         } else {
330                 clk->rate = rate;
331                 ret = 0;
332         }
333 
334         if (clk->ops && clk->ops->recalc)
335                 clk->rate = clk->ops->recalc(clk);
336 
337         propagate_rate(clk);
338 
339 out_unlock:
340         spin_unlock_irqrestore(&clock_lock, flags);
341 
342         return ret;
343 }
344 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
345 
346 int clk_set_parent(struct clk *clk, struct clk *parent)
347 {
348         unsigned long flags;
349         int ret = -EINVAL;
350 
351         if (!parent || !clk)
352                 return ret;
353         if (clk->parent == parent)
354                 return 0;
355 
356         spin_lock_irqsave(&clock_lock, flags);
357         if (clk->usecount == 0) {
358                 if (clk->ops->set_parent)
359                         ret = clk->ops->set_parent(clk, parent);
360                 else
361                         ret = clk_reparent(clk, parent);
362 
363                 if (ret == 0) {
364                         pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
365                                  clk->name, clk->parent->name, clk->rate);
366                         if (clk->ops->recalc)
367                                 clk->rate = clk->ops->recalc(clk);
368                         propagate_rate(clk);
369                 }
370         } else
371                 ret = -EBUSY;
372         spin_unlock_irqrestore(&clock_lock, flags);
373 
374         return ret;
375 }
376 EXPORT_SYMBOL_GPL(clk_set_parent);
377 
378 struct clk *clk_get_parent(struct clk *clk)
379 {
380         return clk->parent;
381 }
382 EXPORT_SYMBOL_GPL(clk_get_parent);
383 
384 long clk_round_rate(struct clk *clk, unsigned long rate)
385 {
386         if (likely(clk->ops && clk->ops->round_rate)) {
387                 unsigned long flags, rounded;
388 
389                 spin_lock_irqsave(&clock_lock, flags);
390                 rounded = clk->ops->round_rate(clk, rate);
391                 spin_unlock_irqrestore(&clock_lock, flags);
392 
393                 return rounded;
394         }
395 
396         return clk_get_rate(clk);
397 }
398 EXPORT_SYMBOL_GPL(clk_round_rate);
399 
400 /*
401  * Find the correct struct clk for the device and connection ID.
402  * We do slightly fuzzy matching here:
403  *  An entry with a NULL ID is assumed to be a wildcard.
404  *  If an entry has a device ID, it must match
405  *  If an entry has a connection ID, it must match
406  * Then we take the most specific entry - with the following
407  * order of precidence: dev+con > dev only > con only.
408  */
409 static struct clk *clk_find(const char *dev_id, const char *con_id)
410 {
411         struct clk_lookup *p;
412         struct clk *clk = NULL;
413         int match, best = 0;
414 
415         list_for_each_entry(p, &clock_list, node) {
416                 match = 0;
417                 if (p->dev_id) {
418                         if (!dev_id || strcmp(p->dev_id, dev_id))
419                                 continue;
420                         match += 2;
421                 }
422                 if (p->con_id) {
423                         if (!con_id || strcmp(p->con_id, con_id))
424                                 continue;
425                         match += 1;
426                 }
427                 if (match == 0)
428                         continue;
429 
430                 if (match > best) {
431                         clk = p->clk;
432                         best = match;
433                 }
434         }
435         return clk;
436 }
437 
438 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
439 {
440         struct clk *clk;
441 
442         mutex_lock(&clock_list_sem);
443         clk = clk_find(dev_id, con_id);
444         mutex_unlock(&clock_list_sem);
445 
446         return clk ? clk : ERR_PTR(-ENOENT);
447 }
448 EXPORT_SYMBOL_GPL(clk_get_sys);
449 
450 /*
451  * Returns a clock. Note that we first try to use device id on the bus
452  * and clock name. If this fails, we try to use clock name only.
453  */
454 struct clk *clk_get(struct device *dev, const char *id)
455 {
456         const char *dev_id = dev ? dev_name(dev) : NULL;
457         struct clk *p, *clk = ERR_PTR(-ENOENT);
458         int idno;
459 
460         clk = clk_get_sys(dev_id, id);
461         if (clk && !IS_ERR(clk))
462                 return clk;
463 
464         if (dev == NULL || dev->bus != &platform_bus_type)
465                 idno = -1;
466         else
467                 idno = to_platform_device(dev)->id;
468 
469         mutex_lock(&clock_list_sem);
470         list_for_each_entry(p, &clock_list, node) {
471                 if (p->id == idno &&
472                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
473                         clk = p;
474                         goto found;
475                 }
476         }
477 
478         list_for_each_entry(p, &clock_list, node) {
479                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
480                         clk = p;
481                         break;
482                 }
483         }
484 
485 found:
486         mutex_unlock(&clock_list_sem);
487 
488         return clk;
489 }
490 EXPORT_SYMBOL_GPL(clk_get);
491 
492 void clk_put(struct clk *clk)
493 {
494         if (clk && !IS_ERR(clk))
495                 module_put(clk->owner);
496 }
497 EXPORT_SYMBOL_GPL(clk_put);
498 
499 #ifdef CONFIG_PM
500 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
501 {
502         static pm_message_t prev_state;
503         struct clk *clkp;
504 
505         switch (state.event) {
506         case PM_EVENT_ON:
507                 /* Resumeing from hibernation */
508                 if (prev_state.event != PM_EVENT_FREEZE)
509                         break;
510 
511                 list_for_each_entry(clkp, &clock_list, node) {
512                         if (likely(clkp->ops)) {
513                                 unsigned long rate = clkp->rate;
514 
515                                 if (likely(clkp->ops->set_parent))
516                                         clkp->ops->set_parent(clkp,
517                                                 clkp->parent);
518                                 if (likely(clkp->ops->set_rate))
519                                         clkp->ops->set_rate(clkp,
520                                                 rate, NO_CHANGE);
521                                 else if (likely(clkp->ops->recalc))
522                                         clkp->rate = clkp->ops->recalc(clkp);
523                         }
524                 }
525                 break;
526         case PM_EVENT_FREEZE:
527                 break;
528         case PM_EVENT_SUSPEND:
529                 break;
530         }
531 
532         prev_state = state;
533         return 0;
534 }
535 
536 static int clks_sysdev_resume(struct sys_device *dev)
537 {
538         return clks_sysdev_suspend(dev, PMSG_ON);
539 }
540 
541 static struct sysdev_class clks_sysdev_class = {
542         .name = "clks",
543 };
544 
545 static struct sysdev_driver clks_sysdev_driver = {
546         .suspend = clks_sysdev_suspend,
547         .resume = clks_sysdev_resume,
548 };
549 
550 static struct sys_device clks_sysdev_dev = {
551         .cls = &clks_sysdev_class,
552 };
553 
554 static int __init clk_sysdev_init(void)
555 {
556         sysdev_class_register(&clks_sysdev_class);
557         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
558         sysdev_register(&clks_sysdev_dev);
559 
560         return 0;
561 }
562 subsys_initcall(clk_sysdev_init);
563 #endif
564 
565 int __init clk_init(void)
566 {
567         int ret;
568 
569         ret = arch_clk_init();
570         if (unlikely(ret)) {
571                 pr_err("%s: CPU clock registration failed.\n", __func__);
572                 return ret;
573         }
574 
575         if (sh_mv.mv_clk_init) {
576                 ret = sh_mv.mv_clk_init();
577                 if (unlikely(ret)) {
578                         pr_err("%s: machvec clock initialization failed.\n",
579                                __func__);
580                         return ret;
581                 }
582         }
583 
584         /* Kick the child clocks.. */
585         recalculate_root_clocks();
586 
587         /* Enable the necessary init clocks */
588         clk_enable_init_clocks();
589 
590         return ret;
591 }
592 
593 /*
594  *      debugfs support to trace clock tree hierarchy and attributes
595  */
596 static struct dentry *clk_debugfs_root;
597 
598 static int clk_debugfs_register_one(struct clk *c)
599 {
600         int err;
601         struct dentry *d, *child;
602         struct clk *pa = c->parent;
603         char s[255];
604         char *p = s;
605 
606         p += sprintf(p, "%s", c->name);
607         if (c->id >= 0)
608                 sprintf(p, ":%d", c->id);
609         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
610         if (!d)
611                 return -ENOMEM;
612         c->dentry = d;
613 
614         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
615         if (!d) {
616                 err = -ENOMEM;
617                 goto err_out;
618         }
619         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
620         if (!d) {
621                 err = -ENOMEM;
622                 goto err_out;
623         }
624         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
625         if (!d) {
626                 err = -ENOMEM;
627                 goto err_out;
628         }
629         return 0;
630 
631 err_out:
632         d = c->dentry;
633         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
634                 debugfs_remove(child);
635         debugfs_remove(c->dentry);
636         return err;
637 }
638 
639 static int clk_debugfs_register(struct clk *c)
640 {
641         int err;
642         struct clk *pa = c->parent;
643 
644         if (pa && !pa->dentry) {
645                 err = clk_debugfs_register(pa);
646                 if (err)
647                         return err;
648         }
649 
650         if (!c->dentry) {
651                 err = clk_debugfs_register_one(c);
652                 if (err)
653                         return err;
654         }
655         return 0;
656 }
657 
658 static int __init clk_debugfs_init(void)
659 {
660         struct clk *c;
661         struct dentry *d;
662         int err;
663 
664         d = debugfs_create_dir("clock", NULL);
665         if (!d)
666                 return -ENOMEM;
667         clk_debugfs_root = d;
668 
669         list_for_each_entry(c, &clock_list, node) {
670                 err = clk_debugfs_register(c);
671                 if (err)
672                         goto err_out;
673         }
674         return 0;
675 err_out:
676         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
677         return err;
678 }
679 late_initcall(clk_debugfs_init);
680 

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