Kobject: convert drivers/* from kobject_unregister() to kobject_put()
[linux-2.6.git] / drivers / cpufreq / cpufreq.c
1 /*
2  *  linux/drivers/cpufreq/cpufreq.c
3  *
4  *  Copyright (C) 2001 Russell King
5  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6  *
7  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8  *      Added handling for CPU hotplug
9  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10  *      Fix handling for CPU hotplug -- affected CPUs
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  *
16  */
17
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/notifier.h>
22 #include <linux/cpufreq.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/device.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
31
32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
33                                                 "cpufreq-core", msg)
34
35 /**
36  * The "cpufreq driver" - the arch- or hardware-dependent low
37  * level driver of CPUFreq support, and its spinlock. This lock
38  * also protects the cpufreq_cpu_data array.
39  */
40 static struct cpufreq_driver *cpufreq_driver;
41 static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static struct cpufreq_governor *cpufreq_cpu_governor[NR_CPUS];
45 #endif
46 static DEFINE_SPINLOCK(cpufreq_driver_lock);
47
48 /*
49  * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50  * all cpufreq/hotplug/workqueue/etc related lock issues.
51  *
52  * The rules for this semaphore:
53  * - Any routine that wants to read from the policy structure will
54  *   do a down_read on this semaphore.
55  * - Any routine that will write to the policy structure and/or may take away
56  *   the policy altogether (eg. CPU hotplug), will hold this lock in write
57  *   mode before doing so.
58  *
59  * Additional rules:
60  * - All holders of the lock should check to make sure that the CPU they
61  *   are concerned with are online after they get the lock.
62  * - Governor routines that can be called in cpufreq hotplug path should not
63  *   take this sem as top level hotplug notifier handler takes this.
64  */
65 static DEFINE_PER_CPU(int, policy_cpu);
66 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
67
68 #define lock_policy_rwsem(mode, cpu)                                    \
69 int lock_policy_rwsem_##mode                                            \
70 (int cpu)                                                               \
71 {                                                                       \
72         int policy_cpu = per_cpu(policy_cpu, cpu);                      \
73         BUG_ON(policy_cpu == -1);                                       \
74         down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu));            \
75         if (unlikely(!cpu_online(cpu))) {                               \
76                 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu));      \
77                 return -1;                                              \
78         }                                                               \
79                                                                         \
80         return 0;                                                       \
81 }
82
83 lock_policy_rwsem(read, cpu);
84 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read);
85
86 lock_policy_rwsem(write, cpu);
87 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write);
88
89 void unlock_policy_rwsem_read(int cpu)
90 {
91         int policy_cpu = per_cpu(policy_cpu, cpu);
92         BUG_ON(policy_cpu == -1);
93         up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
94 }
95 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read);
96
97 void unlock_policy_rwsem_write(int cpu)
98 {
99         int policy_cpu = per_cpu(policy_cpu, cpu);
100         BUG_ON(policy_cpu == -1);
101         up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
102 }
103 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write);
104
105
106 /* internal prototypes */
107 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
108 static unsigned int __cpufreq_get(unsigned int cpu);
109 static void handle_update(struct work_struct *work);
110
111 /**
112  * Two notifier lists: the "policy" list is involved in the
113  * validation process for a new CPU frequency policy; the
114  * "transition" list for kernel code that needs to handle
115  * changes to devices when the CPU clock speed changes.
116  * The mutex locks both lists.
117  */
118 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
119 static struct srcu_notifier_head cpufreq_transition_notifier_list;
120
121 static int __init init_cpufreq_transition_notifier_list(void)
122 {
123         srcu_init_notifier_head(&cpufreq_transition_notifier_list);
124         return 0;
125 }
126 pure_initcall(init_cpufreq_transition_notifier_list);
127
128 static LIST_HEAD(cpufreq_governor_list);
129 static DEFINE_MUTEX (cpufreq_governor_mutex);
130
131 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
132 {
133         struct cpufreq_policy *data;
134         unsigned long flags;
135
136         if (cpu >= NR_CPUS)
137                 goto err_out;
138
139         /* get the cpufreq driver */
140         spin_lock_irqsave(&cpufreq_driver_lock, flags);
141
142         if (!cpufreq_driver)
143                 goto err_out_unlock;
144
145         if (!try_module_get(cpufreq_driver->owner))
146                 goto err_out_unlock;
147
148
149         /* get the CPU */
150         data = cpufreq_cpu_data[cpu];
151
152         if (!data)
153                 goto err_out_put_module;
154
155         if (!kobject_get(&data->kobj))
156                 goto err_out_put_module;
157
158         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
159         return data;
160
161 err_out_put_module:
162         module_put(cpufreq_driver->owner);
163 err_out_unlock:
164         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
165 err_out:
166         return NULL;
167 }
168 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
169
170
171 void cpufreq_cpu_put(struct cpufreq_policy *data)
172 {
173         kobject_put(&data->kobj);
174         module_put(cpufreq_driver->owner);
175 }
176 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
177
178
179 /*********************************************************************
180  *                     UNIFIED DEBUG HELPERS                         *
181  *********************************************************************/
182 #ifdef CONFIG_CPU_FREQ_DEBUG
183
184 /* what part(s) of the CPUfreq subsystem are debugged? */
185 static unsigned int debug;
186
187 /* is the debug output ratelimit'ed using printk_ratelimit? User can
188  * set or modify this value.
189  */
190 static unsigned int debug_ratelimit = 1;
191
192 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
193  * loading of a cpufreq driver, temporarily disabled when a new policy
194  * is set, and disabled upon cpufreq driver removal
195  */
196 static unsigned int disable_ratelimit = 1;
197 static DEFINE_SPINLOCK(disable_ratelimit_lock);
198
199 static void cpufreq_debug_enable_ratelimit(void)
200 {
201         unsigned long flags;
202
203         spin_lock_irqsave(&disable_ratelimit_lock, flags);
204         if (disable_ratelimit)
205                 disable_ratelimit--;
206         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
207 }
208
209 static void cpufreq_debug_disable_ratelimit(void)
210 {
211         unsigned long flags;
212
213         spin_lock_irqsave(&disable_ratelimit_lock, flags);
214         disable_ratelimit++;
215         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
216 }
217
218 void cpufreq_debug_printk(unsigned int type, const char *prefix,
219                                                         const char *fmt, ...)
220 {
221         char s[256];
222         va_list args;
223         unsigned int len;
224         unsigned long flags;
225
226         WARN_ON(!prefix);
227         if (type & debug) {
228                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
229                 if (!disable_ratelimit && debug_ratelimit
230                                         && !printk_ratelimit()) {
231                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
232                         return;
233                 }
234                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
235
236                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
237
238                 va_start(args, fmt);
239                 len += vsnprintf(&s[len], (256 - len), fmt, args);
240                 va_end(args);
241
242                 printk(s);
243
244                 WARN_ON(len < 5);
245         }
246 }
247 EXPORT_SYMBOL(cpufreq_debug_printk);
248
249
250 module_param(debug, uint, 0644);
251 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
252                         " 2 to debug drivers, and 4 to debug governors.");
253
254 module_param(debug_ratelimit, uint, 0644);
255 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
256                                         " set to 0 to disable ratelimiting.");
257
258 #else /* !CONFIG_CPU_FREQ_DEBUG */
259
260 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
261 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
262
263 #endif /* CONFIG_CPU_FREQ_DEBUG */
264
265
266 /*********************************************************************
267  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
268  *********************************************************************/
269
270 /**
271  * adjust_jiffies - adjust the system "loops_per_jiffy"
272  *
273  * This function alters the system "loops_per_jiffy" for the clock
274  * speed change. Note that loops_per_jiffy cannot be updated on SMP
275  * systems as each CPU might be scaled differently. So, use the arch
276  * per-CPU loops_per_jiffy value wherever possible.
277  */
278 #ifndef CONFIG_SMP
279 static unsigned long l_p_j_ref;
280 static unsigned int  l_p_j_ref_freq;
281
282 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
283 {
284         if (ci->flags & CPUFREQ_CONST_LOOPS)
285                 return;
286
287         if (!l_p_j_ref_freq) {
288                 l_p_j_ref = loops_per_jiffy;
289                 l_p_j_ref_freq = ci->old;
290                 dprintk("saving %lu as reference value for loops_per_jiffy;"
291                         "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
292         }
293         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
294             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
295             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
296                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
297                                                                 ci->new);
298                 dprintk("scaling loops_per_jiffy to %lu"
299                         "for frequency %u kHz\n", loops_per_jiffy, ci->new);
300         }
301 }
302 #else
303 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
304 {
305         return;
306 }
307 #endif
308
309
310 /**
311  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
312  * on frequency transition.
313  *
314  * This function calls the transition notifiers and the "adjust_jiffies"
315  * function. It is called twice on all CPU frequency changes that have
316  * external effects.
317  */
318 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
319 {
320         struct cpufreq_policy *policy;
321
322         BUG_ON(irqs_disabled());
323
324         freqs->flags = cpufreq_driver->flags;
325         dprintk("notification %u of frequency transition to %u kHz\n",
326                 state, freqs->new);
327
328         policy = cpufreq_cpu_data[freqs->cpu];
329         switch (state) {
330
331         case CPUFREQ_PRECHANGE:
332                 /* detect if the driver reported a value as "old frequency"
333                  * which is not equal to what the cpufreq core thinks is
334                  * "old frequency".
335                  */
336                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
337                         if ((policy) && (policy->cpu == freqs->cpu) &&
338                             (policy->cur) && (policy->cur != freqs->old)) {
339                                 dprintk("Warning: CPU frequency is"
340                                         " %u, cpufreq assumed %u kHz.\n",
341                                         freqs->old, policy->cur);
342                                 freqs->old = policy->cur;
343                         }
344                 }
345                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
346                                 CPUFREQ_PRECHANGE, freqs);
347                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
348                 break;
349
350         case CPUFREQ_POSTCHANGE:
351                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
352                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
353                                 CPUFREQ_POSTCHANGE, freqs);
354                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
355                         policy->cur = freqs->new;
356                 break;
357         }
358 }
359 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
360
361
362
363 /*********************************************************************
364  *                          SYSFS INTERFACE                          *
365  *********************************************************************/
366
367 static struct cpufreq_governor *__find_governor(const char *str_governor)
368 {
369         struct cpufreq_governor *t;
370
371         list_for_each_entry(t, &cpufreq_governor_list, governor_list)
372                 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN))
373                         return t;
374
375         return NULL;
376 }
377
378 /**
379  * cpufreq_parse_governor - parse a governor string
380  */
381 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
382                                 struct cpufreq_governor **governor)
383 {
384         int err = -EINVAL;
385
386         if (!cpufreq_driver)
387                 goto out;
388
389         if (cpufreq_driver->setpolicy) {
390                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
391                         *policy = CPUFREQ_POLICY_PERFORMANCE;
392                         err = 0;
393                 } else if (!strnicmp(str_governor, "powersave",
394                                                 CPUFREQ_NAME_LEN)) {
395                         *policy = CPUFREQ_POLICY_POWERSAVE;
396                         err = 0;
397                 }
398         } else if (cpufreq_driver->target) {
399                 struct cpufreq_governor *t;
400
401                 mutex_lock(&cpufreq_governor_mutex);
402
403                 t = __find_governor(str_governor);
404
405                 if (t == NULL) {
406                         char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
407                                                                 str_governor);
408
409                         if (name) {
410                                 int ret;
411
412                                 mutex_unlock(&cpufreq_governor_mutex);
413                                 ret = request_module(name);
414                                 mutex_lock(&cpufreq_governor_mutex);
415
416                                 if (ret == 0)
417                                         t = __find_governor(str_governor);
418                         }
419
420                         kfree(name);
421                 }
422
423                 if (t != NULL) {
424                         *governor = t;
425                         err = 0;
426                 }
427
428                 mutex_unlock(&cpufreq_governor_mutex);
429         }
430   out:
431         return err;
432 }
433
434
435 /* drivers/base/cpu.c */
436 extern struct sysdev_class cpu_sysdev_class;
437
438
439 /**
440  * cpufreq_per_cpu_attr_read() / show_##file_name() -
441  * print out cpufreq information
442  *
443  * Write out information from cpufreq_driver->policy[cpu]; object must be
444  * "unsigned int".
445  */
446
447 #define show_one(file_name, object)                     \
448 static ssize_t show_##file_name                         \
449 (struct cpufreq_policy * policy, char *buf)             \
450 {                                                       \
451         return sprintf (buf, "%u\n", policy->object);   \
452 }
453
454 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
455 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
456 show_one(scaling_min_freq, min);
457 show_one(scaling_max_freq, max);
458 show_one(scaling_cur_freq, cur);
459
460 static int __cpufreq_set_policy(struct cpufreq_policy *data,
461                                 struct cpufreq_policy *policy);
462
463 /**
464  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
465  */
466 #define store_one(file_name, object)                    \
467 static ssize_t store_##file_name                                        \
468 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
469 {                                                                       \
470         unsigned int ret = -EINVAL;                                     \
471         struct cpufreq_policy new_policy;                               \
472                                                                         \
473         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
474         if (ret)                                                        \
475                 return -EINVAL;                                         \
476                                                                         \
477         ret = sscanf (buf, "%u", &new_policy.object);                   \
478         if (ret != 1)                                                   \
479                 return -EINVAL;                                         \
480                                                                         \
481         ret = __cpufreq_set_policy(policy, &new_policy);                \
482         policy->user_policy.object = policy->object;                    \
483                                                                         \
484         return ret ? ret : count;                                       \
485 }
486
487 store_one(scaling_min_freq,min);
488 store_one(scaling_max_freq,max);
489
490 /**
491  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
492  */
493 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy,
494                                                         char *buf)
495 {
496         unsigned int cur_freq = __cpufreq_get(policy->cpu);
497         if (!cur_freq)
498                 return sprintf(buf, "<unknown>");
499         return sprintf(buf, "%u\n", cur_freq);
500 }
501
502
503 /**
504  * show_scaling_governor - show the current policy for the specified CPU
505  */
506 static ssize_t show_scaling_governor (struct cpufreq_policy * policy,
507                                                         char *buf)
508 {
509         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
510                 return sprintf(buf, "powersave\n");
511         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
512                 return sprintf(buf, "performance\n");
513         else if (policy->governor)
514                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
515         return -EINVAL;
516 }
517
518
519 /**
520  * store_scaling_governor - store policy for the specified CPU
521  */
522 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
523                                        const char *buf, size_t count)
524 {
525         unsigned int ret = -EINVAL;
526         char    str_governor[16];
527         struct cpufreq_policy new_policy;
528
529         ret = cpufreq_get_policy(&new_policy, policy->cpu);
530         if (ret)
531                 return ret;
532
533         ret = sscanf (buf, "%15s", str_governor);
534         if (ret != 1)
535                 return -EINVAL;
536
537         if (cpufreq_parse_governor(str_governor, &new_policy.policy,
538                                                 &new_policy.governor))
539                 return -EINVAL;
540
541         /* Do not use cpufreq_set_policy here or the user_policy.max
542            will be wrongly overridden */
543         ret = __cpufreq_set_policy(policy, &new_policy);
544
545         policy->user_policy.policy = policy->policy;
546         policy->user_policy.governor = policy->governor;
547
548         if (ret)
549                 return ret;
550         else
551                 return count;
552 }
553
554 /**
555  * show_scaling_driver - show the cpufreq driver currently loaded
556  */
557 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
558 {
559         return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
560 }
561
562 /**
563  * show_scaling_available_governors - show the available CPUfreq governors
564  */
565 static ssize_t show_scaling_available_governors (struct cpufreq_policy *policy,
566                                 char *buf)
567 {
568         ssize_t i = 0;
569         struct cpufreq_governor *t;
570
571         if (!cpufreq_driver->target) {
572                 i += sprintf(buf, "performance powersave");
573                 goto out;
574         }
575
576         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
577                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
578                         goto out;
579                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
580         }
581 out:
582         i += sprintf(&buf[i], "\n");
583         return i;
584 }
585 /**
586  * show_affected_cpus - show the CPUs affected by each transition
587  */
588 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
589 {
590         ssize_t i = 0;
591         unsigned int cpu;
592
593         for_each_cpu_mask(cpu, policy->cpus) {
594                 if (i)
595                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
596                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
597                 if (i >= (PAGE_SIZE - 5))
598                     break;
599         }
600         i += sprintf(&buf[i], "\n");
601         return i;
602 }
603
604
605 #define define_one_ro(_name) \
606 static struct freq_attr _name = \
607 __ATTR(_name, 0444, show_##_name, NULL)
608
609 #define define_one_ro0400(_name) \
610 static struct freq_attr _name = \
611 __ATTR(_name, 0400, show_##_name, NULL)
612
613 #define define_one_rw(_name) \
614 static struct freq_attr _name = \
615 __ATTR(_name, 0644, show_##_name, store_##_name)
616
617 define_one_ro0400(cpuinfo_cur_freq);
618 define_one_ro(cpuinfo_min_freq);
619 define_one_ro(cpuinfo_max_freq);
620 define_one_ro(scaling_available_governors);
621 define_one_ro(scaling_driver);
622 define_one_ro(scaling_cur_freq);
623 define_one_ro(affected_cpus);
624 define_one_rw(scaling_min_freq);
625 define_one_rw(scaling_max_freq);
626 define_one_rw(scaling_governor);
627
628 static struct attribute * default_attrs[] = {
629         &cpuinfo_min_freq.attr,
630         &cpuinfo_max_freq.attr,
631         &scaling_min_freq.attr,
632         &scaling_max_freq.attr,
633         &affected_cpus.attr,
634         &scaling_governor.attr,
635         &scaling_driver.attr,
636         &scaling_available_governors.attr,
637         NULL
638 };
639
640 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
641 #define to_attr(a) container_of(a,struct freq_attr,attr)
642
643 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
644 {
645         struct cpufreq_policy * policy = to_policy(kobj);
646         struct freq_attr * fattr = to_attr(attr);
647         ssize_t ret;
648         policy = cpufreq_cpu_get(policy->cpu);
649         if (!policy)
650                 return -EINVAL;
651
652         if (lock_policy_rwsem_read(policy->cpu) < 0)
653                 return -EINVAL;
654
655         if (fattr->show)
656                 ret = fattr->show(policy, buf);
657         else
658                 ret = -EIO;
659
660         unlock_policy_rwsem_read(policy->cpu);
661
662         cpufreq_cpu_put(policy);
663         return ret;
664 }
665
666 static ssize_t store(struct kobject * kobj, struct attribute * attr,
667                      const char * buf, size_t count)
668 {
669         struct cpufreq_policy * policy = to_policy(kobj);
670         struct freq_attr * fattr = to_attr(attr);
671         ssize_t ret;
672         policy = cpufreq_cpu_get(policy->cpu);
673         if (!policy)
674                 return -EINVAL;
675
676         if (lock_policy_rwsem_write(policy->cpu) < 0)
677                 return -EINVAL;
678
679         if (fattr->store)
680                 ret = fattr->store(policy, buf, count);
681         else
682                 ret = -EIO;
683
684         unlock_policy_rwsem_write(policy->cpu);
685
686         cpufreq_cpu_put(policy);
687         return ret;
688 }
689
690 static void cpufreq_sysfs_release(struct kobject * kobj)
691 {
692         struct cpufreq_policy * policy = to_policy(kobj);
693         dprintk("last reference is dropped\n");
694         complete(&policy->kobj_unregister);
695 }
696
697 static struct sysfs_ops sysfs_ops = {
698         .show   = show,
699         .store  = store,
700 };
701
702 static struct kobj_type ktype_cpufreq = {
703         .sysfs_ops      = &sysfs_ops,
704         .default_attrs  = default_attrs,
705         .release        = cpufreq_sysfs_release,
706 };
707
708
709 /**
710  * cpufreq_add_dev - add a CPU device
711  *
712  * Adds the cpufreq interface for a CPU device.
713  */
714 static int cpufreq_add_dev (struct sys_device * sys_dev)
715 {
716         unsigned int cpu = sys_dev->id;
717         int ret = 0;
718         struct cpufreq_policy new_policy;
719         struct cpufreq_policy *policy;
720         struct freq_attr **drv_attr;
721         struct sys_device *cpu_sys_dev;
722         unsigned long flags;
723         unsigned int j;
724 #ifdef CONFIG_SMP
725         struct cpufreq_policy *managed_policy;
726 #endif
727
728         if (cpu_is_offline(cpu))
729                 return 0;
730
731         cpufreq_debug_disable_ratelimit();
732         dprintk("adding CPU %u\n", cpu);
733
734 #ifdef CONFIG_SMP
735         /* check whether a different CPU already registered this
736          * CPU because it is in the same boat. */
737         policy = cpufreq_cpu_get(cpu);
738         if (unlikely(policy)) {
739                 cpufreq_cpu_put(policy);
740                 cpufreq_debug_enable_ratelimit();
741                 return 0;
742         }
743 #endif
744
745         if (!try_module_get(cpufreq_driver->owner)) {
746                 ret = -EINVAL;
747                 goto module_out;
748         }
749
750         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
751         if (!policy) {
752                 ret = -ENOMEM;
753                 goto nomem_out;
754         }
755
756         policy->cpu = cpu;
757         policy->cpus = cpumask_of_cpu(cpu);
758
759         /* Initially set CPU itself as the policy_cpu */
760         per_cpu(policy_cpu, cpu) = cpu;
761         lock_policy_rwsem_write(cpu);
762
763         init_completion(&policy->kobj_unregister);
764         INIT_WORK(&policy->update, handle_update);
765
766         /* Set governor before ->init, so that driver could check it */
767         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
768         /* call driver. From then on the cpufreq must be able
769          * to accept all calls to ->verify and ->setpolicy for this CPU
770          */
771         ret = cpufreq_driver->init(policy);
772         if (ret) {
773                 dprintk("initialization failed\n");
774                 unlock_policy_rwsem_write(cpu);
775                 goto err_out;
776         }
777         policy->user_policy.min = policy->cpuinfo.min_freq;
778         policy->user_policy.max = policy->cpuinfo.max_freq;
779
780 #ifdef CONFIG_SMP
781
782 #ifdef CONFIG_HOTPLUG_CPU
783         if (cpufreq_cpu_governor[cpu]){
784                 policy->governor = cpufreq_cpu_governor[cpu];
785                 dprintk("Restoring governor %s for cpu %d\n",
786                        policy->governor->name, cpu);
787         }
788 #endif
789
790         for_each_cpu_mask(j, policy->cpus) {
791                 if (cpu == j)
792                         continue;
793
794                 /* check for existing affected CPUs.  They may not be aware
795                  * of it due to CPU Hotplug.
796                  */
797                 managed_policy = cpufreq_cpu_get(j);
798                 if (unlikely(managed_policy)) {
799
800                         /* Set proper policy_cpu */
801                         unlock_policy_rwsem_write(cpu);
802                         per_cpu(policy_cpu, cpu) = managed_policy->cpu;
803
804                         if (lock_policy_rwsem_write(cpu) < 0)
805                                 goto err_out_driver_exit;
806
807                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
808                         managed_policy->cpus = policy->cpus;
809                         cpufreq_cpu_data[cpu] = managed_policy;
810                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
811
812                         dprintk("CPU already managed, adding link\n");
813                         ret = sysfs_create_link(&sys_dev->kobj,
814                                                 &managed_policy->kobj,
815                                                 "cpufreq");
816                         if (ret) {
817                                 unlock_policy_rwsem_write(cpu);
818                                 goto err_out_driver_exit;
819                         }
820
821                         cpufreq_debug_enable_ratelimit();
822                         ret = 0;
823                         unlock_policy_rwsem_write(cpu);
824                         goto err_out_driver_exit; /* call driver->exit() */
825                 }
826         }
827 #endif
828         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
829
830         /* prepare interface data */
831         ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
832                                    "cpufreq");
833         if (ret) {
834                 unlock_policy_rwsem_write(cpu);
835                 goto err_out_driver_exit;
836         }
837         /* set up files for this cpu device */
838         drv_attr = cpufreq_driver->attr;
839         while ((drv_attr) && (*drv_attr)) {
840                 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
841                 if (ret) {
842                         unlock_policy_rwsem_write(cpu);
843                         goto err_out_driver_exit;
844                 }
845                 drv_attr++;
846         }
847         if (cpufreq_driver->get){
848                 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
849                 if (ret) {
850                         unlock_policy_rwsem_write(cpu);
851                         goto err_out_driver_exit;
852                 }
853         }
854         if (cpufreq_driver->target){
855                 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
856                 if (ret) {
857                         unlock_policy_rwsem_write(cpu);
858                         goto err_out_driver_exit;
859                 }
860         }
861
862         spin_lock_irqsave(&cpufreq_driver_lock, flags);
863         for_each_cpu_mask(j, policy->cpus) {
864                 cpufreq_cpu_data[j] = policy;
865                 per_cpu(policy_cpu, j) = policy->cpu;
866         }
867         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
868
869         /* symlink affected CPUs */
870         for_each_cpu_mask(j, policy->cpus) {
871                 if (j == cpu)
872                         continue;
873                 if (!cpu_online(j))
874                         continue;
875
876                 dprintk("CPU %u already managed, adding link\n", j);
877                 cpufreq_cpu_get(cpu);
878                 cpu_sys_dev = get_cpu_sysdev(j);
879                 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
880                                         "cpufreq");
881                 if (ret) {
882                         unlock_policy_rwsem_write(cpu);
883                         goto err_out_unregister;
884                 }
885         }
886
887         policy->governor = NULL; /* to assure that the starting sequence is
888                                   * run in cpufreq_set_policy */
889
890         /* set default policy */
891         ret = __cpufreq_set_policy(policy, &new_policy);
892         policy->user_policy.policy = policy->policy;
893         policy->user_policy.governor = policy->governor;
894
895         unlock_policy_rwsem_write(cpu);
896
897         if (ret) {
898                 dprintk("setting policy failed\n");
899                 goto err_out_unregister;
900         }
901
902         kobject_uevent(&policy->kobj, KOBJ_ADD);
903         module_put(cpufreq_driver->owner);
904         dprintk("initialization complete\n");
905         cpufreq_debug_enable_ratelimit();
906
907         return 0;
908
909
910 err_out_unregister:
911         spin_lock_irqsave(&cpufreq_driver_lock, flags);
912         for_each_cpu_mask(j, policy->cpus)
913                 cpufreq_cpu_data[j] = NULL;
914         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
915
916         kobject_put(&policy->kobj);
917         wait_for_completion(&policy->kobj_unregister);
918
919 err_out_driver_exit:
920         if (cpufreq_driver->exit)
921                 cpufreq_driver->exit(policy);
922
923 err_out:
924         kfree(policy);
925
926 nomem_out:
927         module_put(cpufreq_driver->owner);
928 module_out:
929         cpufreq_debug_enable_ratelimit();
930         return ret;
931 }
932
933
934 /**
935  * __cpufreq_remove_dev - remove a CPU device
936  *
937  * Removes the cpufreq interface for a CPU device.
938  * Caller should already have policy_rwsem in write mode for this CPU.
939  * This routine frees the rwsem before returning.
940  */
941 static int __cpufreq_remove_dev (struct sys_device * sys_dev)
942 {
943         unsigned int cpu = sys_dev->id;
944         unsigned long flags;
945         struct cpufreq_policy *data;
946 #ifdef CONFIG_SMP
947         struct sys_device *cpu_sys_dev;
948         unsigned int j;
949 #endif
950
951         cpufreq_debug_disable_ratelimit();
952         dprintk("unregistering CPU %u\n", cpu);
953
954         spin_lock_irqsave(&cpufreq_driver_lock, flags);
955         data = cpufreq_cpu_data[cpu];
956
957         if (!data) {
958                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
959                 cpufreq_debug_enable_ratelimit();
960                 unlock_policy_rwsem_write(cpu);
961                 return -EINVAL;
962         }
963         cpufreq_cpu_data[cpu] = NULL;
964
965
966 #ifdef CONFIG_SMP
967         /* if this isn't the CPU which is the parent of the kobj, we
968          * only need to unlink, put and exit
969          */
970         if (unlikely(cpu != data->cpu)) {
971                 dprintk("removing link\n");
972                 cpu_clear(cpu, data->cpus);
973                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
974                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
975                 cpufreq_cpu_put(data);
976                 cpufreq_debug_enable_ratelimit();
977                 unlock_policy_rwsem_write(cpu);
978                 return 0;
979         }
980 #endif
981
982
983         if (!kobject_get(&data->kobj)) {
984                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
985                 cpufreq_debug_enable_ratelimit();
986                 unlock_policy_rwsem_write(cpu);
987                 return -EFAULT;
988         }
989
990 #ifdef CONFIG_SMP
991
992 #ifdef CONFIG_HOTPLUG_CPU
993         cpufreq_cpu_governor[cpu] = data->governor;
994 #endif
995
996         /* if we have other CPUs still registered, we need to unlink them,
997          * or else wait_for_completion below will lock up. Clean the
998          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
999          * links afterwards.
1000          */
1001         if (unlikely(cpus_weight(data->cpus) > 1)) {
1002                 for_each_cpu_mask(j, data->cpus) {
1003                         if (j == cpu)
1004                                 continue;
1005                         cpufreq_cpu_data[j] = NULL;
1006                 }
1007         }
1008
1009         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1010
1011         if (unlikely(cpus_weight(data->cpus) > 1)) {
1012                 for_each_cpu_mask(j, data->cpus) {
1013                         if (j == cpu)
1014                                 continue;
1015                         dprintk("removing link for cpu %u\n", j);
1016 #ifdef CONFIG_HOTPLUG_CPU
1017                         cpufreq_cpu_governor[j] = data->governor;
1018 #endif
1019                         cpu_sys_dev = get_cpu_sysdev(j);
1020                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1021                         cpufreq_cpu_put(data);
1022                 }
1023         }
1024 #else
1025         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1026 #endif
1027
1028         if (cpufreq_driver->target)
1029                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1030
1031         unlock_policy_rwsem_write(cpu);
1032
1033         kobject_put(&data->kobj);
1034
1035         /* we need to make sure that the underlying kobj is actually
1036          * not referenced anymore by anybody before we proceed with
1037          * unloading.
1038          */
1039         dprintk("waiting for dropping of refcount\n");
1040         wait_for_completion(&data->kobj_unregister);
1041         dprintk("wait complete\n");
1042
1043         if (cpufreq_driver->exit)
1044                 cpufreq_driver->exit(data);
1045
1046         kfree(data);
1047
1048         cpufreq_debug_enable_ratelimit();
1049         return 0;
1050 }
1051
1052
1053 static int cpufreq_remove_dev (struct sys_device * sys_dev)
1054 {
1055         unsigned int cpu = sys_dev->id;
1056         int retval;
1057
1058         if (cpu_is_offline(cpu))
1059                 return 0;
1060
1061         if (unlikely(lock_policy_rwsem_write(cpu)))
1062                 BUG();
1063
1064         retval = __cpufreq_remove_dev(sys_dev);
1065         return retval;
1066 }
1067
1068
1069 static void handle_update(struct work_struct *work)
1070 {
1071         struct cpufreq_policy *policy =
1072                 container_of(work, struct cpufreq_policy, update);
1073         unsigned int cpu = policy->cpu;
1074         dprintk("handle_update for cpu %u called\n", cpu);
1075         cpufreq_update_policy(cpu);
1076 }
1077
1078 /**
1079  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1080  *      @cpu: cpu number
1081  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
1082  *      @new_freq: CPU frequency the CPU actually runs at
1083  *
1084  *      We adjust to current frequency first, and need to clean up later. So either call
1085  *      to cpufreq_update_policy() or schedule handle_update()).
1086  */
1087 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1088                                 unsigned int new_freq)
1089 {
1090         struct cpufreq_freqs freqs;
1091
1092         dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1093                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1094
1095         freqs.cpu = cpu;
1096         freqs.old = old_freq;
1097         freqs.new = new_freq;
1098         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1099         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1100 }
1101
1102
1103 /**
1104  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1105  * @cpu: CPU number
1106  *
1107  * This is the last known freq, without actually getting it from the driver.
1108  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1109  */
1110 unsigned int cpufreq_quick_get(unsigned int cpu)
1111 {
1112         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1113         unsigned int ret_freq = 0;
1114
1115         if (policy) {
1116                 ret_freq = policy->cur;
1117                 cpufreq_cpu_put(policy);
1118         }
1119
1120         return (ret_freq);
1121 }
1122 EXPORT_SYMBOL(cpufreq_quick_get);
1123
1124
1125 static unsigned int __cpufreq_get(unsigned int cpu)
1126 {
1127         struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1128         unsigned int ret_freq = 0;
1129
1130         if (!cpufreq_driver->get)
1131                 return (ret_freq);
1132
1133         ret_freq = cpufreq_driver->get(cpu);
1134
1135         if (ret_freq && policy->cur &&
1136                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1137                 /* verify no discrepancy between actual and
1138                                         saved value exists */
1139                 if (unlikely(ret_freq != policy->cur)) {
1140                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1141                         schedule_work(&policy->update);
1142                 }
1143         }
1144
1145         return (ret_freq);
1146 }
1147
1148 /**
1149  * cpufreq_get - get the current CPU frequency (in kHz)
1150  * @cpu: CPU number
1151  *
1152  * Get the CPU current (static) CPU frequency
1153  */
1154 unsigned int cpufreq_get(unsigned int cpu)
1155 {
1156         unsigned int ret_freq = 0;
1157         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1158
1159         if (!policy)
1160                 goto out;
1161
1162         if (unlikely(lock_policy_rwsem_read(cpu)))
1163                 goto out_policy;
1164
1165         ret_freq = __cpufreq_get(cpu);
1166
1167         unlock_policy_rwsem_read(cpu);
1168
1169 out_policy:
1170         cpufreq_cpu_put(policy);
1171 out:
1172         return (ret_freq);
1173 }
1174 EXPORT_SYMBOL(cpufreq_get);
1175
1176
1177 /**
1178  *      cpufreq_suspend - let the low level driver prepare for suspend
1179  */
1180
1181 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
1182 {
1183         int cpu = sysdev->id;
1184         int ret = 0;
1185         unsigned int cur_freq = 0;
1186         struct cpufreq_policy *cpu_policy;
1187
1188         dprintk("suspending cpu %u\n", cpu);
1189
1190         if (!cpu_online(cpu))
1191                 return 0;
1192
1193         /* we may be lax here as interrupts are off. Nonetheless
1194          * we need to grab the correct cpu policy, as to check
1195          * whether we really run on this CPU.
1196          */
1197
1198         cpu_policy = cpufreq_cpu_get(cpu);
1199         if (!cpu_policy)
1200                 return -EINVAL;
1201
1202         /* only handle each CPU group once */
1203         if (unlikely(cpu_policy->cpu != cpu)) {
1204                 cpufreq_cpu_put(cpu_policy);
1205                 return 0;
1206         }
1207
1208         if (cpufreq_driver->suspend) {
1209                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1210                 if (ret) {
1211                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1212                                         "step on CPU %u\n", cpu_policy->cpu);
1213                         cpufreq_cpu_put(cpu_policy);
1214                         return ret;
1215                 }
1216         }
1217
1218
1219         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1220                 goto out;
1221
1222         if (cpufreq_driver->get)
1223                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1224
1225         if (!cur_freq || !cpu_policy->cur) {
1226                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1227                        "frequency is what timing core thinks it is.\n");
1228                 goto out;
1229         }
1230
1231         if (unlikely(cur_freq != cpu_policy->cur)) {
1232                 struct cpufreq_freqs freqs;
1233
1234                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1235                         dprintk("Warning: CPU frequency is %u, "
1236                                "cpufreq assumed %u kHz.\n",
1237                                cur_freq, cpu_policy->cur);
1238
1239                 freqs.cpu = cpu;
1240                 freqs.old = cpu_policy->cur;
1241                 freqs.new = cur_freq;
1242
1243                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1244                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1245                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1246
1247                 cpu_policy->cur = cur_freq;
1248         }
1249
1250 out:
1251         cpufreq_cpu_put(cpu_policy);
1252         return 0;
1253 }
1254
1255 /**
1256  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1257  *
1258  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1259  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1260  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1261  *          restored.
1262  */
1263 static int cpufreq_resume(struct sys_device * sysdev)
1264 {
1265         int cpu = sysdev->id;
1266         int ret = 0;
1267         struct cpufreq_policy *cpu_policy;
1268
1269         dprintk("resuming cpu %u\n", cpu);
1270
1271         if (!cpu_online(cpu))
1272                 return 0;
1273
1274         /* we may be lax here as interrupts are off. Nonetheless
1275          * we need to grab the correct cpu policy, as to check
1276          * whether we really run on this CPU.
1277          */
1278
1279         cpu_policy = cpufreq_cpu_get(cpu);
1280         if (!cpu_policy)
1281                 return -EINVAL;
1282
1283         /* only handle each CPU group once */
1284         if (unlikely(cpu_policy->cpu != cpu)) {
1285                 cpufreq_cpu_put(cpu_policy);
1286                 return 0;
1287         }
1288
1289         if (cpufreq_driver->resume) {
1290                 ret = cpufreq_driver->resume(cpu_policy);
1291                 if (ret) {
1292                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1293                                         "step on CPU %u\n", cpu_policy->cpu);
1294                         cpufreq_cpu_put(cpu_policy);
1295                         return ret;
1296                 }
1297         }
1298
1299         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1300                 unsigned int cur_freq = 0;
1301
1302                 if (cpufreq_driver->get)
1303                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1304
1305                 if (!cur_freq || !cpu_policy->cur) {
1306                         printk(KERN_ERR "cpufreq: resume failed to assert "
1307                                         "current frequency is what timing core "
1308                                         "thinks it is.\n");
1309                         goto out;
1310                 }
1311
1312                 if (unlikely(cur_freq != cpu_policy->cur)) {
1313                         struct cpufreq_freqs freqs;
1314
1315                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1316                                 dprintk("Warning: CPU frequency"
1317                                        "is %u, cpufreq assumed %u kHz.\n",
1318                                        cur_freq, cpu_policy->cur);
1319
1320                         freqs.cpu = cpu;
1321                         freqs.old = cpu_policy->cur;
1322                         freqs.new = cur_freq;
1323
1324                         srcu_notifier_call_chain(
1325                                         &cpufreq_transition_notifier_list,
1326                                         CPUFREQ_RESUMECHANGE, &freqs);
1327                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1328
1329                         cpu_policy->cur = cur_freq;
1330                 }
1331         }
1332
1333 out:
1334         schedule_work(&cpu_policy->update);
1335         cpufreq_cpu_put(cpu_policy);
1336         return ret;
1337 }
1338
1339 static struct sysdev_driver cpufreq_sysdev_driver = {
1340         .add            = cpufreq_add_dev,
1341         .remove         = cpufreq_remove_dev,
1342         .suspend        = cpufreq_suspend,
1343         .resume         = cpufreq_resume,
1344 };
1345
1346
1347 /*********************************************************************
1348  *                     NOTIFIER LISTS INTERFACE                      *
1349  *********************************************************************/
1350
1351 /**
1352  *      cpufreq_register_notifier - register a driver with cpufreq
1353  *      @nb: notifier function to register
1354  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1355  *
1356  *      Add a driver to one of two lists: either a list of drivers that
1357  *      are notified about clock rate changes (once before and once after
1358  *      the transition), or a list of drivers that are notified about
1359  *      changes in cpufreq policy.
1360  *
1361  *      This function may sleep, and has the same return conditions as
1362  *      blocking_notifier_chain_register.
1363  */
1364 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1365 {
1366         int ret;
1367
1368         switch (list) {
1369         case CPUFREQ_TRANSITION_NOTIFIER:
1370                 ret = srcu_notifier_chain_register(
1371                                 &cpufreq_transition_notifier_list, nb);
1372                 break;
1373         case CPUFREQ_POLICY_NOTIFIER:
1374                 ret = blocking_notifier_chain_register(
1375                                 &cpufreq_policy_notifier_list, nb);
1376                 break;
1377         default:
1378                 ret = -EINVAL;
1379         }
1380
1381         return ret;
1382 }
1383 EXPORT_SYMBOL(cpufreq_register_notifier);
1384
1385
1386 /**
1387  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1388  *      @nb: notifier block to be unregistered
1389  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1390  *
1391  *      Remove a driver from the CPU frequency notifier list.
1392  *
1393  *      This function may sleep, and has the same return conditions as
1394  *      blocking_notifier_chain_unregister.
1395  */
1396 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1397 {
1398         int ret;
1399
1400         switch (list) {
1401         case CPUFREQ_TRANSITION_NOTIFIER:
1402                 ret = srcu_notifier_chain_unregister(
1403                                 &cpufreq_transition_notifier_list, nb);
1404                 break;
1405         case CPUFREQ_POLICY_NOTIFIER:
1406                 ret = blocking_notifier_chain_unregister(
1407                                 &cpufreq_policy_notifier_list, nb);
1408                 break;
1409         default:
1410                 ret = -EINVAL;
1411         }
1412
1413         return ret;
1414 }
1415 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1416
1417
1418 /*********************************************************************
1419  *                              GOVERNORS                            *
1420  *********************************************************************/
1421
1422
1423 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1424                             unsigned int target_freq,
1425                             unsigned int relation)
1426 {
1427         int retval = -EINVAL;
1428
1429         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1430                 target_freq, relation);
1431         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1432                 retval = cpufreq_driver->target(policy, target_freq, relation);
1433
1434         return retval;
1435 }
1436 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1437
1438 int cpufreq_driver_target(struct cpufreq_policy *policy,
1439                           unsigned int target_freq,
1440                           unsigned int relation)
1441 {
1442         int ret;
1443
1444         policy = cpufreq_cpu_get(policy->cpu);
1445         if (!policy)
1446                 return -EINVAL;
1447
1448         if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1449                 return -EINVAL;
1450
1451         ret = __cpufreq_driver_target(policy, target_freq, relation);
1452
1453         unlock_policy_rwsem_write(policy->cpu);
1454
1455         cpufreq_cpu_put(policy);
1456         return ret;
1457 }
1458 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1459
1460 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1461 {
1462         int ret = 0;
1463
1464         policy = cpufreq_cpu_get(policy->cpu);
1465         if (!policy)
1466                 return -EINVAL;
1467
1468         if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1469                 ret = cpufreq_driver->getavg(policy->cpu);
1470
1471         cpufreq_cpu_put(policy);
1472         return ret;
1473 }
1474 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1475
1476 /*
1477  * when "event" is CPUFREQ_GOV_LIMITS
1478  */
1479
1480 static int __cpufreq_governor(struct cpufreq_policy *policy,
1481                                         unsigned int event)
1482 {
1483         int ret;
1484
1485         /* Only must be defined when default governor is known to have latency
1486            restrictions, like e.g. conservative or ondemand.
1487            That this is the case is already ensured in Kconfig
1488         */
1489 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1490         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1491 #else
1492         struct cpufreq_governor *gov = NULL;
1493 #endif
1494
1495         if (policy->governor->max_transition_latency &&
1496             policy->cpuinfo.transition_latency >
1497             policy->governor->max_transition_latency) {
1498                 if (!gov)
1499                         return -EINVAL;
1500                 else {
1501                         printk(KERN_WARNING "%s governor failed, too long"
1502                                " transition latency of HW, fallback"
1503                                " to %s governor\n",
1504                                policy->governor->name,
1505                                gov->name);
1506                         policy->governor = gov;
1507                 }
1508         }
1509
1510         if (!try_module_get(policy->governor->owner))
1511                 return -EINVAL;
1512
1513         dprintk("__cpufreq_governor for CPU %u, event %u\n",
1514                                                 policy->cpu, event);
1515         ret = policy->governor->governor(policy, event);
1516
1517         /* we keep one module reference alive for
1518                         each CPU governed by this CPU */
1519         if ((event != CPUFREQ_GOV_START) || ret)
1520                 module_put(policy->governor->owner);
1521         if ((event == CPUFREQ_GOV_STOP) && !ret)
1522                 module_put(policy->governor->owner);
1523
1524         return ret;
1525 }
1526
1527
1528 int cpufreq_register_governor(struct cpufreq_governor *governor)
1529 {
1530         int err;
1531
1532         if (!governor)
1533                 return -EINVAL;
1534
1535         mutex_lock(&cpufreq_governor_mutex);
1536
1537         err = -EBUSY;
1538         if (__find_governor(governor->name) == NULL) {
1539                 err = 0;
1540                 list_add(&governor->governor_list, &cpufreq_governor_list);
1541         }
1542
1543         mutex_unlock(&cpufreq_governor_mutex);
1544         return err;
1545 }
1546 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1547
1548
1549 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1550 {
1551         if (!governor)
1552                 return;
1553
1554         mutex_lock(&cpufreq_governor_mutex);
1555         list_del(&governor->governor_list);
1556         mutex_unlock(&cpufreq_governor_mutex);
1557         return;
1558 }
1559 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1560
1561
1562
1563 /*********************************************************************
1564  *                          POLICY INTERFACE                         *
1565  *********************************************************************/
1566
1567 /**
1568  * cpufreq_get_policy - get the current cpufreq_policy
1569  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1570  *
1571  * Reads the current cpufreq policy.
1572  */
1573 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1574 {
1575         struct cpufreq_policy *cpu_policy;
1576         if (!policy)
1577                 return -EINVAL;
1578
1579         cpu_policy = cpufreq_cpu_get(cpu);
1580         if (!cpu_policy)
1581                 return -EINVAL;
1582
1583         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1584
1585         cpufreq_cpu_put(cpu_policy);
1586         return 0;
1587 }
1588 EXPORT_SYMBOL(cpufreq_get_policy);
1589
1590
1591 /*
1592  * data   : current policy.
1593  * policy : policy to be set.
1594  */
1595 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1596                                 struct cpufreq_policy *policy)
1597 {
1598         int ret = 0;
1599
1600         cpufreq_debug_disable_ratelimit();
1601         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1602                 policy->min, policy->max);
1603
1604         memcpy(&policy->cpuinfo, &data->cpuinfo,
1605                                 sizeof(struct cpufreq_cpuinfo));
1606
1607         if (policy->min > data->min && policy->min > policy->max) {
1608                 ret = -EINVAL;
1609                 goto error_out;
1610         }
1611
1612         /* verify the cpu speed can be set within this limit */
1613         ret = cpufreq_driver->verify(policy);
1614         if (ret)
1615                 goto error_out;
1616
1617         /* adjust if necessary - all reasons */
1618         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1619                         CPUFREQ_ADJUST, policy);
1620
1621         /* adjust if necessary - hardware incompatibility*/
1622         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1623                         CPUFREQ_INCOMPATIBLE, policy);
1624
1625         /* verify the cpu speed can be set within this limit,
1626            which might be different to the first one */
1627         ret = cpufreq_driver->verify(policy);
1628         if (ret)
1629                 goto error_out;
1630
1631         /* notification of the new policy */
1632         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1633                         CPUFREQ_NOTIFY, policy);
1634
1635         data->min = policy->min;
1636         data->max = policy->max;
1637
1638         dprintk("new min and max freqs are %u - %u kHz\n",
1639                                         data->min, data->max);
1640
1641         if (cpufreq_driver->setpolicy) {
1642                 data->policy = policy->policy;
1643                 dprintk("setting range\n");
1644                 ret = cpufreq_driver->setpolicy(policy);
1645         } else {
1646                 if (policy->governor != data->governor) {
1647                         /* save old, working values */
1648                         struct cpufreq_governor *old_gov = data->governor;
1649
1650                         dprintk("governor switch\n");
1651
1652                         /* end old governor */
1653                         if (data->governor)
1654                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1655
1656                         /* start new governor */
1657                         data->governor = policy->governor;
1658                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1659                                 /* new governor failed, so re-start old one */
1660                                 dprintk("starting governor %s failed\n",
1661                                                         data->governor->name);
1662                                 if (old_gov) {
1663                                         data->governor = old_gov;
1664                                         __cpufreq_governor(data,
1665                                                            CPUFREQ_GOV_START);
1666                                 }
1667                                 ret = -EINVAL;
1668                                 goto error_out;
1669                         }
1670                         /* might be a policy change, too, so fall through */
1671                 }
1672                 dprintk("governor: change or update limits\n");
1673                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1674         }
1675
1676 error_out:
1677         cpufreq_debug_enable_ratelimit();
1678         return ret;
1679 }
1680
1681 /**
1682  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1683  *      @cpu: CPU which shall be re-evaluated
1684  *
1685  *      Usefull for policy notifiers which have different necessities
1686  *      at different times.
1687  */
1688 int cpufreq_update_policy(unsigned int cpu)
1689 {
1690         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1691         struct cpufreq_policy policy;
1692         int ret = 0;
1693
1694         if (!data)
1695                 return -ENODEV;
1696
1697         if (unlikely(lock_policy_rwsem_write(cpu)))
1698                 return -EINVAL;
1699
1700         dprintk("updating policy for CPU %u\n", cpu);
1701         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1702         policy.min = data->user_policy.min;
1703         policy.max = data->user_policy.max;
1704         policy.policy = data->user_policy.policy;
1705         policy.governor = data->user_policy.governor;
1706
1707         /* BIOS might change freq behind our back
1708           -> ask driver for current freq and notify governors about a change */
1709         if (cpufreq_driver->get) {
1710                 policy.cur = cpufreq_driver->get(cpu);
1711                 if (!data->cur) {
1712                         dprintk("Driver did not initialize current freq");
1713                         data->cur = policy.cur;
1714                 } else {
1715                         if (data->cur != policy.cur)
1716                                 cpufreq_out_of_sync(cpu, data->cur,
1717                                                                 policy.cur);
1718                 }
1719         }
1720
1721         ret = __cpufreq_set_policy(data, &policy);
1722
1723         unlock_policy_rwsem_write(cpu);
1724
1725         cpufreq_cpu_put(data);
1726         return ret;
1727 }
1728 EXPORT_SYMBOL(cpufreq_update_policy);
1729
1730 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1731                                         unsigned long action, void *hcpu)
1732 {
1733         unsigned int cpu = (unsigned long)hcpu;
1734         struct sys_device *sys_dev;
1735
1736         sys_dev = get_cpu_sysdev(cpu);
1737         if (sys_dev) {
1738                 switch (action) {
1739                 case CPU_ONLINE:
1740                 case CPU_ONLINE_FROZEN:
1741                         cpufreq_add_dev(sys_dev);
1742                         break;
1743                 case CPU_DOWN_PREPARE:
1744                 case CPU_DOWN_PREPARE_FROZEN:
1745                         if (unlikely(lock_policy_rwsem_write(cpu)))
1746                                 BUG();
1747
1748                         __cpufreq_remove_dev(sys_dev);
1749                         break;
1750                 case CPU_DOWN_FAILED:
1751                 case CPU_DOWN_FAILED_FROZEN:
1752                         cpufreq_add_dev(sys_dev);
1753                         break;
1754                 }
1755         }
1756         return NOTIFY_OK;
1757 }
1758
1759 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1760 {
1761     .notifier_call = cpufreq_cpu_callback,
1762 };
1763
1764 /*********************************************************************
1765  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1766  *********************************************************************/
1767
1768 /**
1769  * cpufreq_register_driver - register a CPU Frequency driver
1770  * @driver_data: A struct cpufreq_driver containing the values#
1771  * submitted by the CPU Frequency driver.
1772  *
1773  *   Registers a CPU Frequency driver to this core code. This code
1774  * returns zero on success, -EBUSY when another driver got here first
1775  * (and isn't unregistered in the meantime).
1776  *
1777  */
1778 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1779 {
1780         unsigned long flags;
1781         int ret;
1782
1783         if (!driver_data || !driver_data->verify || !driver_data->init ||
1784             ((!driver_data->setpolicy) && (!driver_data->target)))
1785                 return -EINVAL;
1786
1787         dprintk("trying to register driver %s\n", driver_data->name);
1788
1789         if (driver_data->setpolicy)
1790                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1791
1792         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1793         if (cpufreq_driver) {
1794                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1795                 return -EBUSY;
1796         }
1797         cpufreq_driver = driver_data;
1798         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1799
1800         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1801
1802         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1803                 int i;
1804                 ret = -ENODEV;
1805
1806                 /* check for at least one working CPU */
1807                 for (i=0; i<NR_CPUS; i++)
1808                         if (cpufreq_cpu_data[i])
1809                                 ret = 0;
1810
1811                 /* if all ->init() calls failed, unregister */
1812                 if (ret) {
1813                         dprintk("no CPU initialized for driver %s\n",
1814                                                         driver_data->name);
1815                         sysdev_driver_unregister(&cpu_sysdev_class,
1816                                                 &cpufreq_sysdev_driver);
1817
1818                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1819                         cpufreq_driver = NULL;
1820                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1821                 }
1822         }
1823
1824         if (!ret) {
1825                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1826                 dprintk("driver %s up and running\n", driver_data->name);
1827                 cpufreq_debug_enable_ratelimit();
1828         }
1829
1830         return (ret);
1831 }
1832 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1833
1834
1835 /**
1836  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1837  *
1838  *    Unregister the current CPUFreq driver. Only call this if you have
1839  * the right to do so, i.e. if you have succeeded in initialising before!
1840  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1841  * currently not initialised.
1842  */
1843 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1844 {
1845         unsigned long flags;
1846
1847         cpufreq_debug_disable_ratelimit();
1848
1849         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1850                 cpufreq_debug_enable_ratelimit();
1851                 return -EINVAL;
1852         }
1853
1854         dprintk("unregistering driver %s\n", driver->name);
1855
1856         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1857         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1858
1859         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1860         cpufreq_driver = NULL;
1861         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1862
1863         return 0;
1864 }
1865 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1866
1867 static int __init cpufreq_core_init(void)
1868 {
1869         int cpu;
1870
1871         for_each_possible_cpu(cpu) {
1872                 per_cpu(policy_cpu, cpu) = -1;
1873                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1874         }
1875         return 0;
1876 }
1877
1878 core_initcall(cpufreq_core_init);