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