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