[CPUFREQ] Fix a kobject reference bug related to managed CPUs
[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 DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static DEFINE_PER_CPU(struct cpufreq_governor *, cpufreq_cpu_governor);
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,
108                 unsigned int event);
109 static unsigned int __cpufreq_get(unsigned int cpu);
110 static void handle_update(struct work_struct *work);
111
112 /**
113  * Two notifier lists: the "policy" list is involved in the
114  * validation process for a new CPU frequency policy; the
115  * "transition" list for kernel code that needs to handle
116  * changes to devices when the CPU clock speed changes.
117  * The mutex locks both lists.
118  */
119 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
120 static struct srcu_notifier_head cpufreq_transition_notifier_list;
121
122 static bool init_cpufreq_transition_notifier_list_called;
123 static int __init init_cpufreq_transition_notifier_list(void)
124 {
125         srcu_init_notifier_head(&cpufreq_transition_notifier_list);
126         init_cpufreq_transition_notifier_list_called = true;
127         return 0;
128 }
129 pure_initcall(init_cpufreq_transition_notifier_list);
130
131 static LIST_HEAD(cpufreq_governor_list);
132 static DEFINE_MUTEX(cpufreq_governor_mutex);
133
134 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
135 {
136         struct cpufreq_policy *data;
137         unsigned long flags;
138
139         if (cpu >= nr_cpu_ids)
140                 goto err_out;
141
142         /* get the cpufreq driver */
143         spin_lock_irqsave(&cpufreq_driver_lock, flags);
144
145         if (!cpufreq_driver)
146                 goto err_out_unlock;
147
148         if (!try_module_get(cpufreq_driver->owner))
149                 goto err_out_unlock;
150
151
152         /* get the CPU */
153         data = per_cpu(cpufreq_cpu_data, cpu);
154
155         if (!data)
156                 goto err_out_put_module;
157
158         if (!kobject_get(&data->kobj))
159                 goto err_out_put_module;
160
161         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
162         return data;
163
164 err_out_put_module:
165         module_put(cpufreq_driver->owner);
166 err_out_unlock:
167         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
168 err_out:
169         return NULL;
170 }
171 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
172
173
174 void cpufreq_cpu_put(struct cpufreq_policy *data)
175 {
176         kobject_put(&data->kobj);
177         module_put(cpufreq_driver->owner);
178 }
179 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
180
181
182 /*********************************************************************
183  *                     UNIFIED DEBUG HELPERS                         *
184  *********************************************************************/
185 #ifdef CONFIG_CPU_FREQ_DEBUG
186
187 /* what part(s) of the CPUfreq subsystem are debugged? */
188 static unsigned int debug;
189
190 /* is the debug output ratelimit'ed using printk_ratelimit? User can
191  * set or modify this value.
192  */
193 static unsigned int debug_ratelimit = 1;
194
195 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
196  * loading of a cpufreq driver, temporarily disabled when a new policy
197  * is set, and disabled upon cpufreq driver removal
198  */
199 static unsigned int disable_ratelimit = 1;
200 static DEFINE_SPINLOCK(disable_ratelimit_lock);
201
202 static void cpufreq_debug_enable_ratelimit(void)
203 {
204         unsigned long flags;
205
206         spin_lock_irqsave(&disable_ratelimit_lock, flags);
207         if (disable_ratelimit)
208                 disable_ratelimit--;
209         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
210 }
211
212 static void cpufreq_debug_disable_ratelimit(void)
213 {
214         unsigned long flags;
215
216         spin_lock_irqsave(&disable_ratelimit_lock, flags);
217         disable_ratelimit++;
218         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
219 }
220
221 void cpufreq_debug_printk(unsigned int type, const char *prefix,
222                         const char *fmt, ...)
223 {
224         char s[256];
225         va_list args;
226         unsigned int len;
227         unsigned long flags;
228
229         WARN_ON(!prefix);
230         if (type & debug) {
231                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
232                 if (!disable_ratelimit && debug_ratelimit
233                                         && !printk_ratelimit()) {
234                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
235                         return;
236                 }
237                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
238
239                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
240
241                 va_start(args, fmt);
242                 len += vsnprintf(&s[len], (256 - len), fmt, args);
243                 va_end(args);
244
245                 printk(s);
246
247                 WARN_ON(len < 5);
248         }
249 }
250 EXPORT_SYMBOL(cpufreq_debug_printk);
251
252
253 module_param(debug, uint, 0644);
254 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
255                         " 2 to debug drivers, and 4 to debug governors.");
256
257 module_param(debug_ratelimit, uint, 0644);
258 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
259                                         " set to 0 to disable ratelimiting.");
260
261 #else /* !CONFIG_CPU_FREQ_DEBUG */
262
263 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
264 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
265
266 #endif /* CONFIG_CPU_FREQ_DEBUG */
267
268
269 /*********************************************************************
270  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
271  *********************************************************************/
272
273 /**
274  * adjust_jiffies - adjust the system "loops_per_jiffy"
275  *
276  * This function alters the system "loops_per_jiffy" for the clock
277  * speed change. Note that loops_per_jiffy cannot be updated on SMP
278  * systems as each CPU might be scaled differently. So, use the arch
279  * per-CPU loops_per_jiffy value wherever possible.
280  */
281 #ifndef CONFIG_SMP
282 static unsigned long l_p_j_ref;
283 static unsigned int  l_p_j_ref_freq;
284
285 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
286 {
287         if (ci->flags & CPUFREQ_CONST_LOOPS)
288                 return;
289
290         if (!l_p_j_ref_freq) {
291                 l_p_j_ref = loops_per_jiffy;
292                 l_p_j_ref_freq = ci->old;
293                 dprintk("saving %lu as reference value for loops_per_jiffy; "
294                         "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
295         }
296         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
297             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
298             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
299                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
300                                                                 ci->new);
301                 dprintk("scaling loops_per_jiffy to %lu "
302                         "for frequency %u kHz\n", loops_per_jiffy, ci->new);
303         }
304 }
305 #else
306 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
307 {
308         return;
309 }
310 #endif
311
312
313 /**
314  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
315  * on frequency transition.
316  *
317  * This function calls the transition notifiers and the "adjust_jiffies"
318  * function. It is called twice on all CPU frequency changes that have
319  * external effects.
320  */
321 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
322 {
323         struct cpufreq_policy *policy;
324
325         BUG_ON(irqs_disabled());
326
327         freqs->flags = cpufreq_driver->flags;
328         dprintk("notification %u of frequency transition to %u kHz\n",
329                 state, freqs->new);
330
331         policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
332         switch (state) {
333
334         case CPUFREQ_PRECHANGE:
335                 /* detect if the driver reported a value as "old frequency"
336                  * which is not equal to what the cpufreq core thinks is
337                  * "old frequency".
338                  */
339                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
340                         if ((policy) && (policy->cpu == freqs->cpu) &&
341                             (policy->cur) && (policy->cur != freqs->old)) {
342                                 dprintk("Warning: CPU frequency is"
343                                         " %u, cpufreq assumed %u kHz.\n",
344                                         freqs->old, policy->cur);
345                                 freqs->old = policy->cur;
346                         }
347                 }
348                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
349                                 CPUFREQ_PRECHANGE, freqs);
350                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
351                 break;
352
353         case CPUFREQ_POSTCHANGE:
354                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
355                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
356                                 CPUFREQ_POSTCHANGE, freqs);
357                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
358                         policy->cur = freqs->new;
359                 break;
360         }
361 }
362 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
363
364
365
366 /*********************************************************************
367  *                          SYSFS INTERFACE                          *
368  *********************************************************************/
369
370 static struct cpufreq_governor *__find_governor(const char *str_governor)
371 {
372         struct cpufreq_governor *t;
373
374         list_for_each_entry(t, &cpufreq_governor_list, governor_list)
375                 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
376                         return t;
377
378         return NULL;
379 }
380
381 /**
382  * cpufreq_parse_governor - parse a governor string
383  */
384 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
385                                 struct cpufreq_governor **governor)
386 {
387         int err = -EINVAL;
388
389         if (!cpufreq_driver)
390                 goto out;
391
392         if (cpufreq_driver->setpolicy) {
393                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
394                         *policy = CPUFREQ_POLICY_PERFORMANCE;
395                         err = 0;
396                 } else if (!strnicmp(str_governor, "powersave",
397                                                 CPUFREQ_NAME_LEN)) {
398                         *policy = CPUFREQ_POLICY_POWERSAVE;
399                         err = 0;
400                 }
401         } else if (cpufreq_driver->target) {
402                 struct cpufreq_governor *t;
403
404                 mutex_lock(&cpufreq_governor_mutex);
405
406                 t = __find_governor(str_governor);
407
408                 if (t == NULL) {
409                         char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
410                                                                 str_governor);
411
412                         if (name) {
413                                 int ret;
414
415                                 mutex_unlock(&cpufreq_governor_mutex);
416                                 ret = request_module("%s", name);
417                                 mutex_lock(&cpufreq_governor_mutex);
418
419                                 if (ret == 0)
420                                         t = __find_governor(str_governor);
421                         }
422
423                         kfree(name);
424                 }
425
426                 if (t != NULL) {
427                         *governor = t;
428                         err = 0;
429                 }
430
431                 mutex_unlock(&cpufreq_governor_mutex);
432         }
433 out:
434         return err;
435 }
436
437
438 /**
439  * cpufreq_per_cpu_attr_read() / show_##file_name() -
440  * print out cpufreq information
441  *
442  * Write out information from cpufreq_driver->policy[cpu]; object must be
443  * "unsigned int".
444  */
445
446 #define show_one(file_name, object)                     \
447 static ssize_t show_##file_name                         \
448 (struct cpufreq_policy *policy, char *buf)              \
449 {                                                       \
450         return sprintf(buf, "%u\n", policy->object);    \
451 }
452
453 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
454 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
455 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
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, char *buf)
507 {
508         if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
509                 return sprintf(buf, "powersave\n");
510         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
511                 return sprintf(buf, "performance\n");
512         else if (policy->governor)
513                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
514                                 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))
578                     - (CPUFREQ_NAME_LEN + 2)))
579                         goto out;
580                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
581         }
582 out:
583         i += sprintf(&buf[i], "\n");
584         return i;
585 }
586
587 static ssize_t show_cpus(const struct cpumask *mask, char *buf)
588 {
589         ssize_t i = 0;
590         unsigned int cpu;
591
592         for_each_cpu(cpu, mask) {
593                 if (i)
594                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
595                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
596                 if (i >= (PAGE_SIZE - 5))
597                         break;
598         }
599         i += sprintf(&buf[i], "\n");
600         return i;
601 }
602
603 /**
604  * show_related_cpus - show the CPUs affected by each transition even if
605  * hw coordination is in use
606  */
607 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
608 {
609         if (cpumask_empty(policy->related_cpus))
610                 return show_cpus(policy->cpus, buf);
611         return show_cpus(policy->related_cpus, buf);
612 }
613
614 /**
615  * show_affected_cpus - show the CPUs affected by each transition
616  */
617 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
618 {
619         return show_cpus(policy->cpus, buf);
620 }
621
622 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
623                                         const char *buf, size_t count)
624 {
625         unsigned int freq = 0;
626         unsigned int ret;
627
628         if (!policy->governor || !policy->governor->store_setspeed)
629                 return -EINVAL;
630
631         ret = sscanf(buf, "%u", &freq);
632         if (ret != 1)
633                 return -EINVAL;
634
635         policy->governor->store_setspeed(policy, freq);
636
637         return count;
638 }
639
640 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
641 {
642         if (!policy->governor || !policy->governor->show_setspeed)
643                 return sprintf(buf, "<unsupported>\n");
644
645         return policy->governor->show_setspeed(policy, buf);
646 }
647
648 #define define_one_ro(_name) \
649 static struct freq_attr _name = \
650 __ATTR(_name, 0444, show_##_name, NULL)
651
652 #define define_one_ro0400(_name) \
653 static struct freq_attr _name = \
654 __ATTR(_name, 0400, show_##_name, NULL)
655
656 #define define_one_rw(_name) \
657 static struct freq_attr _name = \
658 __ATTR(_name, 0644, show_##_name, store_##_name)
659
660 define_one_ro0400(cpuinfo_cur_freq);
661 define_one_ro(cpuinfo_min_freq);
662 define_one_ro(cpuinfo_max_freq);
663 define_one_ro(cpuinfo_transition_latency);
664 define_one_ro(scaling_available_governors);
665 define_one_ro(scaling_driver);
666 define_one_ro(scaling_cur_freq);
667 define_one_ro(related_cpus);
668 define_one_ro(affected_cpus);
669 define_one_rw(scaling_min_freq);
670 define_one_rw(scaling_max_freq);
671 define_one_rw(scaling_governor);
672 define_one_rw(scaling_setspeed);
673
674 static struct attribute *default_attrs[] = {
675         &cpuinfo_min_freq.attr,
676         &cpuinfo_max_freq.attr,
677         &cpuinfo_transition_latency.attr,
678         &scaling_min_freq.attr,
679         &scaling_max_freq.attr,
680         &affected_cpus.attr,
681         &related_cpus.attr,
682         &scaling_governor.attr,
683         &scaling_driver.attr,
684         &scaling_available_governors.attr,
685         &scaling_setspeed.attr,
686         NULL
687 };
688
689 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
690 #define to_attr(a) container_of(a, struct freq_attr, attr)
691
692 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
693 {
694         struct cpufreq_policy *policy = to_policy(kobj);
695         struct freq_attr *fattr = to_attr(attr);
696         ssize_t ret = -EINVAL;
697         policy = cpufreq_cpu_get(policy->cpu);
698         if (!policy)
699                 goto no_policy;
700
701         if (lock_policy_rwsem_read(policy->cpu) < 0)
702                 goto fail;
703
704         if (fattr->show)
705                 ret = fattr->show(policy, buf);
706         else
707                 ret = -EIO;
708
709         unlock_policy_rwsem_read(policy->cpu);
710 fail:
711         cpufreq_cpu_put(policy);
712 no_policy:
713         return ret;
714 }
715
716 static ssize_t store(struct kobject *kobj, struct attribute *attr,
717                      const char *buf, size_t count)
718 {
719         struct cpufreq_policy *policy = to_policy(kobj);
720         struct freq_attr *fattr = to_attr(attr);
721         ssize_t ret = -EINVAL;
722         policy = cpufreq_cpu_get(policy->cpu);
723         if (!policy)
724                 goto no_policy;
725
726         if (lock_policy_rwsem_write(policy->cpu) < 0)
727                 goto fail;
728
729         if (fattr->store)
730                 ret = fattr->store(policy, buf, count);
731         else
732                 ret = -EIO;
733
734         unlock_policy_rwsem_write(policy->cpu);
735 fail:
736         cpufreq_cpu_put(policy);
737 no_policy:
738         return ret;
739 }
740
741 static void cpufreq_sysfs_release(struct kobject *kobj)
742 {
743         struct cpufreq_policy *policy = to_policy(kobj);
744         dprintk("last reference is dropped\n");
745         complete(&policy->kobj_unregister);
746 }
747
748 static struct sysfs_ops sysfs_ops = {
749         .show   = show,
750         .store  = store,
751 };
752
753 static struct kobj_type ktype_cpufreq = {
754         .sysfs_ops      = &sysfs_ops,
755         .default_attrs  = default_attrs,
756         .release        = cpufreq_sysfs_release,
757 };
758
759
760 /**
761  * cpufreq_add_dev - add a CPU device
762  *
763  * Adds the cpufreq interface for a CPU device.
764  *
765  * The Oracle says: try running cpufreq registration/unregistration concurrently
766  * with with cpu hotplugging and all hell will break loose. Tried to clean this
767  * mess up, but more thorough testing is needed. - Mathieu
768  */
769 static int cpufreq_add_dev(struct sys_device *sys_dev)
770 {
771         unsigned int cpu = sys_dev->id;
772         int ret = 0;
773         struct cpufreq_policy new_policy;
774         struct cpufreq_policy *policy;
775         struct freq_attr **drv_attr;
776         struct sys_device *cpu_sys_dev;
777         unsigned long flags;
778         unsigned int j;
779
780         if (cpu_is_offline(cpu))
781                 return 0;
782
783         cpufreq_debug_disable_ratelimit();
784         dprintk("adding CPU %u\n", cpu);
785
786 #ifdef CONFIG_SMP
787         /* check whether a different CPU already registered this
788          * CPU because it is in the same boat. */
789         policy = cpufreq_cpu_get(cpu);
790         if (unlikely(policy)) {
791                 cpufreq_cpu_put(policy);
792                 cpufreq_debug_enable_ratelimit();
793                 return 0;
794         }
795 #endif
796
797         if (!try_module_get(cpufreq_driver->owner)) {
798                 ret = -EINVAL;
799                 goto module_out;
800         }
801
802         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
803         if (!policy) {
804                 ret = -ENOMEM;
805                 goto nomem_out;
806         }
807         if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) {
808                 ret = -ENOMEM;
809                 goto err_free_policy;
810         }
811         if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
812                 ret = -ENOMEM;
813                 goto err_free_cpumask;
814         }
815
816         policy->cpu = cpu;
817         cpumask_copy(policy->cpus, cpumask_of(cpu));
818
819         /* Initially set CPU itself as the policy_cpu */
820         per_cpu(policy_cpu, cpu) = cpu;
821         ret = (lock_policy_rwsem_write(cpu) < 0);
822         WARN_ON(ret);
823
824         init_completion(&policy->kobj_unregister);
825         INIT_WORK(&policy->update, handle_update);
826
827         /* Set governor before ->init, so that driver could check it */
828         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
829         /* call driver. From then on the cpufreq must be able
830          * to accept all calls to ->verify and ->setpolicy for this CPU
831          */
832         ret = cpufreq_driver->init(policy);
833         if (ret) {
834                 dprintk("initialization failed\n");
835                 goto err_unlock_policy;
836         }
837         policy->user_policy.min = policy->min;
838         policy->user_policy.max = policy->max;
839
840         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
841                                      CPUFREQ_START, policy);
842
843 #ifdef CONFIG_SMP
844
845 #ifdef CONFIG_HOTPLUG_CPU
846         if (per_cpu(cpufreq_cpu_governor, cpu)) {
847                 policy->governor = per_cpu(cpufreq_cpu_governor, cpu);
848                 dprintk("Restoring governor %s for cpu %d\n",
849                        policy->governor->name, cpu);
850         }
851 #endif
852
853         for_each_cpu(j, policy->cpus) {
854                 struct cpufreq_policy *managed_policy;
855
856                 if (cpu == j)
857                         continue;
858
859                 /* Check for existing affected CPUs.
860                  * They may not be aware of it due to CPU Hotplug.
861                  * cpufreq_cpu_put is called when the device is removed
862                  * in __cpufreq_remove_dev()
863                  */
864                 managed_policy = cpufreq_cpu_get(j);
865                 if (unlikely(managed_policy)) {
866
867                         /* Set proper policy_cpu */
868                         unlock_policy_rwsem_write(cpu);
869                         per_cpu(policy_cpu, cpu) = managed_policy->cpu;
870
871                         if (lock_policy_rwsem_write(cpu) < 0) {
872                                 /* Should not go through policy unlock path */
873                                 if (cpufreq_driver->exit)
874                                         cpufreq_driver->exit(policy);
875                                 ret = -EBUSY;
876                                 cpufreq_cpu_put(managed_policy);
877                                 goto err_free_cpumask;
878                         }
879
880                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
881                         cpumask_copy(managed_policy->cpus, policy->cpus);
882                         per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
883                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
884
885                         dprintk("CPU already managed, adding link\n");
886                         ret = sysfs_create_link(&sys_dev->kobj,
887                                                 &managed_policy->kobj,
888                                                 "cpufreq");
889                         if (ret)
890                                 cpufreq_cpu_put(managed_policy);
891                         /*
892                          * Success. We only needed to be added to the mask.
893                          * Call driver->exit() because only the cpu parent of
894                          * the kobj needed to call init().
895                          */
896                         goto out_driver_exit; /* call driver->exit() */
897                 }
898         }
899 #endif
900         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
901
902         /* prepare interface data */
903         ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
904                                    "cpufreq");
905         if (ret)
906                 goto out_driver_exit;
907
908         /* set up files for this cpu device */
909         drv_attr = cpufreq_driver->attr;
910         while ((drv_attr) && (*drv_attr)) {
911                 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
912                 if (ret)
913                         goto err_out_kobj_put;
914                 drv_attr++;
915         }
916         if (cpufreq_driver->get) {
917                 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
918                 if (ret)
919                         goto err_out_kobj_put;
920         }
921         if (cpufreq_driver->target) {
922                 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
923                 if (ret)
924                         goto err_out_kobj_put;
925         }
926
927         spin_lock_irqsave(&cpufreq_driver_lock, flags);
928         for_each_cpu(j, policy->cpus) {
929                 if (!cpu_online(j))
930                         continue;
931                 per_cpu(cpufreq_cpu_data, j) = policy;
932                 per_cpu(policy_cpu, j) = policy->cpu;
933         }
934         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
935
936         /* symlink affected CPUs */
937         for_each_cpu(j, policy->cpus) {
938                 struct cpufreq_policy *managed_policy;
939
940                 if (j == cpu)
941                         continue;
942                 if (!cpu_online(j))
943                         continue;
944
945                 dprintk("CPU %u already managed, adding link\n", j);
946                 managed_policy = cpufreq_cpu_get(cpu);
947                 cpu_sys_dev = get_cpu_sysdev(j);
948                 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
949                                         "cpufreq");
950                 if (ret) {
951                         cpufreq_cpu_put(managed_policy);
952                         goto err_out_unregister;
953                 }
954         }
955
956         policy->governor = NULL; /* to assure that the starting sequence is
957                                   * run in cpufreq_set_policy */
958
959         /* set default policy */
960         ret = __cpufreq_set_policy(policy, &new_policy);
961         policy->user_policy.policy = policy->policy;
962         policy->user_policy.governor = policy->governor;
963
964         if (ret) {
965                 dprintk("setting policy failed\n");
966                 goto err_out_unregister;
967         }
968
969         unlock_policy_rwsem_write(cpu);
970
971         kobject_uevent(&policy->kobj, KOBJ_ADD);
972         module_put(cpufreq_driver->owner);
973         dprintk("initialization complete\n");
974         cpufreq_debug_enable_ratelimit();
975
976         return 0;
977
978
979 err_out_unregister:
980         spin_lock_irqsave(&cpufreq_driver_lock, flags);
981         for_each_cpu(j, policy->cpus)
982                 per_cpu(cpufreq_cpu_data, j) = NULL;
983         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
984
985 err_out_kobj_put:
986         kobject_put(&policy->kobj);
987         wait_for_completion(&policy->kobj_unregister);
988
989 out_driver_exit:
990         if (cpufreq_driver->exit)
991                 cpufreq_driver->exit(policy);
992
993 err_unlock_policy:
994         unlock_policy_rwsem_write(cpu);
995 err_free_cpumask:
996         free_cpumask_var(policy->cpus);
997 err_free_policy:
998         kfree(policy);
999 nomem_out:
1000         module_put(cpufreq_driver->owner);
1001 module_out:
1002         cpufreq_debug_enable_ratelimit();
1003         return ret;
1004 }
1005
1006
1007 /**
1008  * __cpufreq_remove_dev - remove a CPU device
1009  *
1010  * Removes the cpufreq interface for a CPU device.
1011  * Caller should already have policy_rwsem in write mode for this CPU.
1012  * This routine frees the rwsem before returning.
1013  */
1014 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1015 {
1016         unsigned int cpu = sys_dev->id;
1017         unsigned long flags;
1018         struct cpufreq_policy *data;
1019 #ifdef CONFIG_SMP
1020         struct sys_device *cpu_sys_dev;
1021         unsigned int j;
1022 #endif
1023
1024         cpufreq_debug_disable_ratelimit();
1025         dprintk("unregistering CPU %u\n", cpu);
1026
1027         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1028         data = per_cpu(cpufreq_cpu_data, cpu);
1029
1030         if (!data) {
1031                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1032                 cpufreq_debug_enable_ratelimit();
1033                 unlock_policy_rwsem_write(cpu);
1034                 return -EINVAL;
1035         }
1036         per_cpu(cpufreq_cpu_data, cpu) = NULL;
1037
1038
1039 #ifdef CONFIG_SMP
1040         /* if this isn't the CPU which is the parent of the kobj, we
1041          * only need to unlink, put and exit
1042          */
1043         if (unlikely(cpu != data->cpu)) {
1044                 dprintk("removing link\n");
1045                 cpumask_clear_cpu(cpu, data->cpus);
1046                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1047                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
1048                 cpufreq_cpu_put(data);
1049                 cpufreq_debug_enable_ratelimit();
1050                 unlock_policy_rwsem_write(cpu);
1051                 return 0;
1052         }
1053 #endif
1054
1055 #ifdef CONFIG_SMP
1056
1057 #ifdef CONFIG_HOTPLUG_CPU
1058         per_cpu(cpufreq_cpu_governor, cpu) = data->governor;
1059 #endif
1060
1061         /* if we have other CPUs still registered, we need to unlink them,
1062          * or else wait_for_completion below will lock up. Clean the
1063          * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1064          * the sysfs links afterwards.
1065          */
1066         if (unlikely(cpumask_weight(data->cpus) > 1)) {
1067                 for_each_cpu(j, data->cpus) {
1068                         if (j == cpu)
1069                                 continue;
1070                         per_cpu(cpufreq_cpu_data, j) = NULL;
1071                 }
1072         }
1073
1074         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1075
1076         if (unlikely(cpumask_weight(data->cpus) > 1)) {
1077                 for_each_cpu(j, data->cpus) {
1078                         if (j == cpu)
1079                                 continue;
1080                         dprintk("removing link for cpu %u\n", j);
1081 #ifdef CONFIG_HOTPLUG_CPU
1082                         per_cpu(cpufreq_cpu_governor, j) = data->governor;
1083 #endif
1084                         cpu_sys_dev = get_cpu_sysdev(j);
1085                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1086                         cpufreq_cpu_put(data);
1087                 }
1088         }
1089 #else
1090         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1091 #endif
1092
1093         if (cpufreq_driver->target)
1094                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1095
1096         kobject_put(&data->kobj);
1097
1098         /* we need to make sure that the underlying kobj is actually
1099          * not referenced anymore by anybody before we proceed with
1100          * unloading.
1101          */
1102         dprintk("waiting for dropping of refcount\n");
1103         wait_for_completion(&data->kobj_unregister);
1104         dprintk("wait complete\n");
1105
1106         if (cpufreq_driver->exit)
1107                 cpufreq_driver->exit(data);
1108
1109         unlock_policy_rwsem_write(cpu);
1110
1111         free_cpumask_var(data->related_cpus);
1112         free_cpumask_var(data->cpus);
1113         kfree(data);
1114         per_cpu(cpufreq_cpu_data, cpu) = NULL;
1115
1116         cpufreq_debug_enable_ratelimit();
1117         return 0;
1118 }
1119
1120
1121 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1122 {
1123         unsigned int cpu = sys_dev->id;
1124         int retval;
1125
1126         if (cpu_is_offline(cpu))
1127                 return 0;
1128
1129         if (unlikely(lock_policy_rwsem_write(cpu)))
1130                 BUG();
1131
1132         retval = __cpufreq_remove_dev(sys_dev);
1133         return retval;
1134 }
1135
1136
1137 static void handle_update(struct work_struct *work)
1138 {
1139         struct cpufreq_policy *policy =
1140                 container_of(work, struct cpufreq_policy, update);
1141         unsigned int cpu = policy->cpu;
1142         dprintk("handle_update for cpu %u called\n", cpu);
1143         cpufreq_update_policy(cpu);
1144 }
1145
1146 /**
1147  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1148  *      @cpu: cpu number
1149  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
1150  *      @new_freq: CPU frequency the CPU actually runs at
1151  *
1152  *      We adjust to current frequency first, and need to clean up later.
1153  *      So either call to cpufreq_update_policy() or schedule handle_update()).
1154  */
1155 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1156                                 unsigned int new_freq)
1157 {
1158         struct cpufreq_freqs freqs;
1159
1160         dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1161                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1162
1163         freqs.cpu = cpu;
1164         freqs.old = old_freq;
1165         freqs.new = new_freq;
1166         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1167         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1168 }
1169
1170
1171 /**
1172  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1173  * @cpu: CPU number
1174  *
1175  * This is the last known freq, without actually getting it from the driver.
1176  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1177  */
1178 unsigned int cpufreq_quick_get(unsigned int cpu)
1179 {
1180         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1181         unsigned int ret_freq = 0;
1182
1183         if (policy) {
1184                 ret_freq = policy->cur;
1185                 cpufreq_cpu_put(policy);
1186         }
1187
1188         return ret_freq;
1189 }
1190 EXPORT_SYMBOL(cpufreq_quick_get);
1191
1192
1193 static unsigned int __cpufreq_get(unsigned int cpu)
1194 {
1195         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1196         unsigned int ret_freq = 0;
1197
1198         if (!cpufreq_driver->get)
1199                 return ret_freq;
1200
1201         ret_freq = cpufreq_driver->get(cpu);
1202
1203         if (ret_freq && policy->cur &&
1204                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1205                 /* verify no discrepancy between actual and
1206                                         saved value exists */
1207                 if (unlikely(ret_freq != policy->cur)) {
1208                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1209                         schedule_work(&policy->update);
1210                 }
1211         }
1212
1213         return ret_freq;
1214 }
1215
1216 /**
1217  * cpufreq_get - get the current CPU frequency (in kHz)
1218  * @cpu: CPU number
1219  *
1220  * Get the CPU current (static) CPU frequency
1221  */
1222 unsigned int cpufreq_get(unsigned int cpu)
1223 {
1224         unsigned int ret_freq = 0;
1225         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1226
1227         if (!policy)
1228                 goto out;
1229
1230         if (unlikely(lock_policy_rwsem_read(cpu)))
1231                 goto out_policy;
1232
1233         ret_freq = __cpufreq_get(cpu);
1234
1235         unlock_policy_rwsem_read(cpu);
1236
1237 out_policy:
1238         cpufreq_cpu_put(policy);
1239 out:
1240         return ret_freq;
1241 }
1242 EXPORT_SYMBOL(cpufreq_get);
1243
1244
1245 /**
1246  *      cpufreq_suspend - let the low level driver prepare for suspend
1247  */
1248
1249 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1250 {
1251         int cpu = sysdev->id;
1252         int ret = 0;
1253         unsigned int cur_freq = 0;
1254         struct cpufreq_policy *cpu_policy;
1255
1256         dprintk("suspending cpu %u\n", cpu);
1257
1258         if (!cpu_online(cpu))
1259                 return 0;
1260
1261         /* we may be lax here as interrupts are off. Nonetheless
1262          * we need to grab the correct cpu policy, as to check
1263          * whether we really run on this CPU.
1264          */
1265
1266         cpu_policy = cpufreq_cpu_get(cpu);
1267         if (!cpu_policy)
1268                 return -EINVAL;
1269
1270         /* only handle each CPU group once */
1271         if (unlikely(cpu_policy->cpu != cpu))
1272                 goto out;
1273
1274         if (cpufreq_driver->suspend) {
1275                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1276                 if (ret) {
1277                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1278                                         "step on CPU %u\n", cpu_policy->cpu);
1279                         goto out;
1280                 }
1281         }
1282
1283         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1284                 goto out;
1285
1286         if (cpufreq_driver->get)
1287                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1288
1289         if (!cur_freq || !cpu_policy->cur) {
1290                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1291                        "frequency is what timing core thinks it is.\n");
1292                 goto out;
1293         }
1294
1295         if (unlikely(cur_freq != cpu_policy->cur)) {
1296                 struct cpufreq_freqs freqs;
1297
1298                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1299                         dprintk("Warning: CPU frequency is %u, "
1300                                "cpufreq assumed %u kHz.\n",
1301                                cur_freq, cpu_policy->cur);
1302
1303                 freqs.cpu = cpu;
1304                 freqs.old = cpu_policy->cur;
1305                 freqs.new = cur_freq;
1306
1307                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1308                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1309                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1310
1311                 cpu_policy->cur = cur_freq;
1312         }
1313
1314 out:
1315         cpufreq_cpu_put(cpu_policy);
1316         return ret;
1317 }
1318
1319 /**
1320  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1321  *
1322  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1323  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1324  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1325  *          restored.
1326  */
1327 static int cpufreq_resume(struct sys_device *sysdev)
1328 {
1329         int cpu = sysdev->id;
1330         int ret = 0;
1331         struct cpufreq_policy *cpu_policy;
1332
1333         dprintk("resuming cpu %u\n", cpu);
1334
1335         if (!cpu_online(cpu))
1336                 return 0;
1337
1338         /* we may be lax here as interrupts are off. Nonetheless
1339          * we need to grab the correct cpu policy, as to check
1340          * whether we really run on this CPU.
1341          */
1342
1343         cpu_policy = cpufreq_cpu_get(cpu);
1344         if (!cpu_policy)
1345                 return -EINVAL;
1346
1347         /* only handle each CPU group once */
1348         if (unlikely(cpu_policy->cpu != cpu))
1349                 goto fail;
1350
1351         if (cpufreq_driver->resume) {
1352                 ret = cpufreq_driver->resume(cpu_policy);
1353                 if (ret) {
1354                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1355                                         "step on CPU %u\n", cpu_policy->cpu);
1356                         goto fail;
1357                 }
1358         }
1359
1360         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1361                 unsigned int cur_freq = 0;
1362
1363                 if (cpufreq_driver->get)
1364                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1365
1366                 if (!cur_freq || !cpu_policy->cur) {
1367                         printk(KERN_ERR "cpufreq: resume failed to assert "
1368                                         "current frequency is what timing core "
1369                                         "thinks it is.\n");
1370                         goto out;
1371                 }
1372
1373                 if (unlikely(cur_freq != cpu_policy->cur)) {
1374                         struct cpufreq_freqs freqs;
1375
1376                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1377                                 dprintk("Warning: CPU frequency "
1378                                        "is %u, cpufreq assumed %u kHz.\n",
1379                                        cur_freq, cpu_policy->cur);
1380
1381                         freqs.cpu = cpu;
1382                         freqs.old = cpu_policy->cur;
1383                         freqs.new = cur_freq;
1384
1385                         srcu_notifier_call_chain(
1386                                         &cpufreq_transition_notifier_list,
1387                                         CPUFREQ_RESUMECHANGE, &freqs);
1388                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1389
1390                         cpu_policy->cur = cur_freq;
1391                 }
1392         }
1393
1394 out:
1395         schedule_work(&cpu_policy->update);
1396 fail:
1397         cpufreq_cpu_put(cpu_policy);
1398         return ret;
1399 }
1400
1401 static struct sysdev_driver cpufreq_sysdev_driver = {
1402         .add            = cpufreq_add_dev,
1403         .remove         = cpufreq_remove_dev,
1404         .suspend        = cpufreq_suspend,
1405         .resume         = cpufreq_resume,
1406 };
1407
1408
1409 /*********************************************************************
1410  *                     NOTIFIER LISTS INTERFACE                      *
1411  *********************************************************************/
1412
1413 /**
1414  *      cpufreq_register_notifier - register a driver with cpufreq
1415  *      @nb: notifier function to register
1416  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1417  *
1418  *      Add a driver to one of two lists: either a list of drivers that
1419  *      are notified about clock rate changes (once before and once after
1420  *      the transition), or a list of drivers that are notified about
1421  *      changes in cpufreq policy.
1422  *
1423  *      This function may sleep, and has the same return conditions as
1424  *      blocking_notifier_chain_register.
1425  */
1426 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1427 {
1428         int ret;
1429
1430         WARN_ON(!init_cpufreq_transition_notifier_list_called);
1431
1432         switch (list) {
1433         case CPUFREQ_TRANSITION_NOTIFIER:
1434                 ret = srcu_notifier_chain_register(
1435                                 &cpufreq_transition_notifier_list, nb);
1436                 break;
1437         case CPUFREQ_POLICY_NOTIFIER:
1438                 ret = blocking_notifier_chain_register(
1439                                 &cpufreq_policy_notifier_list, nb);
1440                 break;
1441         default:
1442                 ret = -EINVAL;
1443         }
1444
1445         return ret;
1446 }
1447 EXPORT_SYMBOL(cpufreq_register_notifier);
1448
1449
1450 /**
1451  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1452  *      @nb: notifier block to be unregistered
1453  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1454  *
1455  *      Remove a driver from the CPU frequency notifier list.
1456  *
1457  *      This function may sleep, and has the same return conditions as
1458  *      blocking_notifier_chain_unregister.
1459  */
1460 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1461 {
1462         int ret;
1463
1464         switch (list) {
1465         case CPUFREQ_TRANSITION_NOTIFIER:
1466                 ret = srcu_notifier_chain_unregister(
1467                                 &cpufreq_transition_notifier_list, nb);
1468                 break;
1469         case CPUFREQ_POLICY_NOTIFIER:
1470                 ret = blocking_notifier_chain_unregister(
1471                                 &cpufreq_policy_notifier_list, nb);
1472                 break;
1473         default:
1474                 ret = -EINVAL;
1475         }
1476
1477         return ret;
1478 }
1479 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1480
1481
1482 /*********************************************************************
1483  *                              GOVERNORS                            *
1484  *********************************************************************/
1485
1486
1487 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1488                             unsigned int target_freq,
1489                             unsigned int relation)
1490 {
1491         int retval = -EINVAL;
1492
1493         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1494                 target_freq, relation);
1495         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1496                 retval = cpufreq_driver->target(policy, target_freq, relation);
1497
1498         return retval;
1499 }
1500 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1501
1502 int cpufreq_driver_target(struct cpufreq_policy *policy,
1503                           unsigned int target_freq,
1504                           unsigned int relation)
1505 {
1506         int ret = -EINVAL;
1507
1508         policy = cpufreq_cpu_get(policy->cpu);
1509         if (!policy)
1510                 goto no_policy;
1511
1512         if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1513                 goto fail;
1514
1515         ret = __cpufreq_driver_target(policy, target_freq, relation);
1516
1517         unlock_policy_rwsem_write(policy->cpu);
1518
1519 fail:
1520         cpufreq_cpu_put(policy);
1521 no_policy:
1522         return ret;
1523 }
1524 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1525
1526 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1527 {
1528         int ret = 0;
1529
1530         policy = cpufreq_cpu_get(policy->cpu);
1531         if (!policy)
1532                 return -EINVAL;
1533
1534         if (cpu_online(cpu) && cpufreq_driver->getavg)
1535                 ret = cpufreq_driver->getavg(policy, cpu);
1536
1537         cpufreq_cpu_put(policy);
1538         return ret;
1539 }
1540 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1541
1542 /*
1543  * when "event" is CPUFREQ_GOV_LIMITS
1544  */
1545
1546 static int __cpufreq_governor(struct cpufreq_policy *policy,
1547                                         unsigned int event)
1548 {
1549         int ret;
1550
1551         /* Only must be defined when default governor is known to have latency
1552            restrictions, like e.g. conservative or ondemand.
1553            That this is the case is already ensured in Kconfig
1554         */
1555 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1556         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1557 #else
1558         struct cpufreq_governor *gov = NULL;
1559 #endif
1560
1561         if (policy->governor->max_transition_latency &&
1562             policy->cpuinfo.transition_latency >
1563             policy->governor->max_transition_latency) {
1564                 if (!gov)
1565                         return -EINVAL;
1566                 else {
1567                         printk(KERN_WARNING "%s governor failed, too long"
1568                                " transition latency of HW, fallback"
1569                                " to %s governor\n",
1570                                policy->governor->name,
1571                                gov->name);
1572                         policy->governor = gov;
1573                 }
1574         }
1575
1576         if (!try_module_get(policy->governor->owner))
1577                 return -EINVAL;
1578
1579         dprintk("__cpufreq_governor for CPU %u, event %u\n",
1580                                                 policy->cpu, event);
1581         ret = policy->governor->governor(policy, event);
1582
1583         /* we keep one module reference alive for
1584                         each CPU governed by this CPU */
1585         if ((event != CPUFREQ_GOV_START) || ret)
1586                 module_put(policy->governor->owner);
1587         if ((event == CPUFREQ_GOV_STOP) && !ret)
1588                 module_put(policy->governor->owner);
1589
1590         return ret;
1591 }
1592
1593
1594 int cpufreq_register_governor(struct cpufreq_governor *governor)
1595 {
1596         int err;
1597
1598         if (!governor)
1599                 return -EINVAL;
1600
1601         mutex_lock(&cpufreq_governor_mutex);
1602
1603         err = -EBUSY;
1604         if (__find_governor(governor->name) == NULL) {
1605                 err = 0;
1606                 list_add(&governor->governor_list, &cpufreq_governor_list);
1607         }
1608
1609         mutex_unlock(&cpufreq_governor_mutex);
1610         return err;
1611 }
1612 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1613
1614
1615 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1616 {
1617         if (!governor)
1618                 return;
1619
1620         mutex_lock(&cpufreq_governor_mutex);
1621         list_del(&governor->governor_list);
1622         mutex_unlock(&cpufreq_governor_mutex);
1623         return;
1624 }
1625 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1626
1627
1628
1629 /*********************************************************************
1630  *                          POLICY INTERFACE                         *
1631  *********************************************************************/
1632
1633 /**
1634  * cpufreq_get_policy - get the current cpufreq_policy
1635  * @policy: struct cpufreq_policy into which the current cpufreq_policy
1636  *      is written
1637  *
1638  * Reads the current cpufreq policy.
1639  */
1640 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1641 {
1642         struct cpufreq_policy *cpu_policy;
1643         if (!policy)
1644                 return -EINVAL;
1645
1646         cpu_policy = cpufreq_cpu_get(cpu);
1647         if (!cpu_policy)
1648                 return -EINVAL;
1649
1650         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1651
1652         cpufreq_cpu_put(cpu_policy);
1653         return 0;
1654 }
1655 EXPORT_SYMBOL(cpufreq_get_policy);
1656
1657
1658 /*
1659  * data   : current policy.
1660  * policy : policy to be set.
1661  */
1662 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1663                                 struct cpufreq_policy *policy)
1664 {
1665         int ret = 0;
1666
1667         cpufreq_debug_disable_ratelimit();
1668         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1669                 policy->min, policy->max);
1670
1671         memcpy(&policy->cpuinfo, &data->cpuinfo,
1672                                 sizeof(struct cpufreq_cpuinfo));
1673
1674         if (policy->min > data->max || policy->max < data->min) {
1675                 ret = -EINVAL;
1676                 goto error_out;
1677         }
1678
1679         /* verify the cpu speed can be set within this limit */
1680         ret = cpufreq_driver->verify(policy);
1681         if (ret)
1682                 goto error_out;
1683
1684         /* adjust if necessary - all reasons */
1685         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1686                         CPUFREQ_ADJUST, policy);
1687
1688         /* adjust if necessary - hardware incompatibility*/
1689         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1690                         CPUFREQ_INCOMPATIBLE, policy);
1691
1692         /* verify the cpu speed can be set within this limit,
1693            which might be different to the first one */
1694         ret = cpufreq_driver->verify(policy);
1695         if (ret)
1696                 goto error_out;
1697
1698         /* notification of the new policy */
1699         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1700                         CPUFREQ_NOTIFY, policy);
1701
1702         data->min = policy->min;
1703         data->max = policy->max;
1704
1705         dprintk("new min and max freqs are %u - %u kHz\n",
1706                                         data->min, data->max);
1707
1708         if (cpufreq_driver->setpolicy) {
1709                 data->policy = policy->policy;
1710                 dprintk("setting range\n");
1711                 ret = cpufreq_driver->setpolicy(policy);
1712         } else {
1713                 if (policy->governor != data->governor) {
1714                         /* save old, working values */
1715                         struct cpufreq_governor *old_gov = data->governor;
1716
1717                         dprintk("governor switch\n");
1718
1719                         /* end old governor */
1720                         if (data->governor)
1721                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1722
1723                         /* start new governor */
1724                         data->governor = policy->governor;
1725                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1726                                 /* new governor failed, so re-start old one */
1727                                 dprintk("starting governor %s failed\n",
1728                                                         data->governor->name);
1729                                 if (old_gov) {
1730                                         data->governor = old_gov;
1731                                         __cpufreq_governor(data,
1732                                                            CPUFREQ_GOV_START);
1733                                 }
1734                                 ret = -EINVAL;
1735                                 goto error_out;
1736                         }
1737                         /* might be a policy change, too, so fall through */
1738                 }
1739                 dprintk("governor: change or update limits\n");
1740                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1741         }
1742
1743 error_out:
1744         cpufreq_debug_enable_ratelimit();
1745         return ret;
1746 }
1747
1748 /**
1749  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1750  *      @cpu: CPU which shall be re-evaluated
1751  *
1752  *      Usefull for policy notifiers which have different necessities
1753  *      at different times.
1754  */
1755 int cpufreq_update_policy(unsigned int cpu)
1756 {
1757         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1758         struct cpufreq_policy policy;
1759         int ret;
1760
1761         if (!data) {
1762                 ret = -ENODEV;
1763                 goto no_policy;
1764         }
1765
1766         if (unlikely(lock_policy_rwsem_write(cpu))) {
1767                 ret = -EINVAL;
1768                 goto fail;
1769         }
1770
1771         dprintk("updating policy for CPU %u\n", cpu);
1772         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1773         policy.min = data->user_policy.min;
1774         policy.max = data->user_policy.max;
1775         policy.policy = data->user_policy.policy;
1776         policy.governor = data->user_policy.governor;
1777
1778         /* BIOS might change freq behind our back
1779           -> ask driver for current freq and notify governors about a change */
1780         if (cpufreq_driver->get) {
1781                 policy.cur = cpufreq_driver->get(cpu);
1782                 if (!data->cur) {
1783                         dprintk("Driver did not initialize current freq");
1784                         data->cur = policy.cur;
1785                 } else {
1786                         if (data->cur != policy.cur)
1787                                 cpufreq_out_of_sync(cpu, data->cur,
1788                                                                 policy.cur);
1789                 }
1790         }
1791
1792         ret = __cpufreq_set_policy(data, &policy);
1793
1794         unlock_policy_rwsem_write(cpu);
1795
1796 fail:
1797         cpufreq_cpu_put(data);
1798 no_policy:
1799         return ret;
1800 }
1801 EXPORT_SYMBOL(cpufreq_update_policy);
1802
1803 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1804                                         unsigned long action, void *hcpu)
1805 {
1806         unsigned int cpu = (unsigned long)hcpu;
1807         struct sys_device *sys_dev;
1808
1809         sys_dev = get_cpu_sysdev(cpu);
1810         if (sys_dev) {
1811                 switch (action) {
1812                 case CPU_ONLINE:
1813                 case CPU_ONLINE_FROZEN:
1814                         cpufreq_add_dev(sys_dev);
1815                         break;
1816                 case CPU_DOWN_PREPARE:
1817                 case CPU_DOWN_PREPARE_FROZEN:
1818                         if (unlikely(lock_policy_rwsem_write(cpu)))
1819                                 BUG();
1820
1821                         __cpufreq_remove_dev(sys_dev);
1822                         break;
1823                 case CPU_DOWN_FAILED:
1824                 case CPU_DOWN_FAILED_FROZEN:
1825                         cpufreq_add_dev(sys_dev);
1826                         break;
1827                 }
1828         }
1829         return NOTIFY_OK;
1830 }
1831
1832 static struct notifier_block __refdata cpufreq_cpu_notifier =
1833 {
1834     .notifier_call = cpufreq_cpu_callback,
1835 };
1836
1837 /*********************************************************************
1838  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1839  *********************************************************************/
1840
1841 /**
1842  * cpufreq_register_driver - register a CPU Frequency driver
1843  * @driver_data: A struct cpufreq_driver containing the values#
1844  * submitted by the CPU Frequency driver.
1845  *
1846  *   Registers a CPU Frequency driver to this core code. This code
1847  * returns zero on success, -EBUSY when another driver got here first
1848  * (and isn't unregistered in the meantime).
1849  *
1850  */
1851 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1852 {
1853         unsigned long flags;
1854         int ret;
1855
1856         if (!driver_data || !driver_data->verify || !driver_data->init ||
1857             ((!driver_data->setpolicy) && (!driver_data->target)))
1858                 return -EINVAL;
1859
1860         dprintk("trying to register driver %s\n", driver_data->name);
1861
1862         if (driver_data->setpolicy)
1863                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1864
1865         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1866         if (cpufreq_driver) {
1867                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1868                 return -EBUSY;
1869         }
1870         cpufreq_driver = driver_data;
1871         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1872
1873         ret = sysdev_driver_register(&cpu_sysdev_class,
1874                                         &cpufreq_sysdev_driver);
1875
1876         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1877                 int i;
1878                 ret = -ENODEV;
1879
1880                 /* check for at least one working CPU */
1881                 for (i = 0; i < nr_cpu_ids; i++)
1882                         if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1883                                 ret = 0;
1884                                 break;
1885                         }
1886
1887                 /* if all ->init() calls failed, unregister */
1888                 if (ret) {
1889                         dprintk("no CPU initialized for driver %s\n",
1890                                                         driver_data->name);
1891                         sysdev_driver_unregister(&cpu_sysdev_class,
1892                                                 &cpufreq_sysdev_driver);
1893
1894                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1895                         cpufreq_driver = NULL;
1896                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1897                 }
1898         }
1899
1900         if (!ret) {
1901                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1902                 dprintk("driver %s up and running\n", driver_data->name);
1903                 cpufreq_debug_enable_ratelimit();
1904         }
1905
1906         return ret;
1907 }
1908 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1909
1910
1911 /**
1912  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1913  *
1914  *    Unregister the current CPUFreq driver. Only call this if you have
1915  * the right to do so, i.e. if you have succeeded in initialising before!
1916  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1917  * currently not initialised.
1918  */
1919 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1920 {
1921         unsigned long flags;
1922
1923         cpufreq_debug_disable_ratelimit();
1924
1925         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1926                 cpufreq_debug_enable_ratelimit();
1927                 return -EINVAL;
1928         }
1929
1930         dprintk("unregistering driver %s\n", driver->name);
1931
1932         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1933         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1934
1935         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1936         cpufreq_driver = NULL;
1937         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1938
1939         return 0;
1940 }
1941 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1942
1943 static int __init cpufreq_core_init(void)
1944 {
1945         int cpu;
1946
1947         for_each_possible_cpu(cpu) {
1948                 per_cpu(policy_cpu, cpu) = -1;
1949                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1950         }
1951         return 0;
1952 }
1953
1954 core_initcall(cpufreq_core_init);