x86: be careful about tailcall breakage for sys_open[at] too
[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 already managed, adding link\n");
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         
701         ret = cpufreq_set_policy(&new_policy);
702         if (ret) {
703                 dprintk("setting policy failed\n");
704                 goto err_out_unregister;
705         }
706
707         module_put(cpufreq_driver->owner);
708         dprintk("initialization complete\n");
709         cpufreq_debug_enable_ratelimit();
710         
711         return 0;
712
713
714 err_out_unregister:
715         spin_lock_irqsave(&cpufreq_driver_lock, flags);
716         for_each_cpu_mask(j, policy->cpus)
717                 cpufreq_cpu_data[j] = NULL;
718         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
719
720         kobject_unregister(&policy->kobj);
721         wait_for_completion(&policy->kobj_unregister);
722
723 err_out_driver_exit:
724         if (cpufreq_driver->exit)
725                 cpufreq_driver->exit(policy);
726
727 err_out:
728         kfree(policy);
729
730 nomem_out:
731         module_put(cpufreq_driver->owner);
732 module_out:
733         cpufreq_debug_enable_ratelimit();
734         return ret;
735 }
736
737
738 /**
739  * cpufreq_remove_dev - remove a CPU device
740  *
741  * Removes the cpufreq interface for a CPU device.
742  */
743 static int cpufreq_remove_dev (struct sys_device * sys_dev)
744 {
745         unsigned int cpu = sys_dev->id;
746         unsigned long flags;
747         struct cpufreq_policy *data;
748 #ifdef CONFIG_SMP
749         struct sys_device *cpu_sys_dev;
750         unsigned int j;
751 #endif
752
753         cpufreq_debug_disable_ratelimit();
754         dprintk("unregistering CPU %u\n", cpu);
755
756         spin_lock_irqsave(&cpufreq_driver_lock, flags);
757         data = cpufreq_cpu_data[cpu];
758
759         if (!data) {
760                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
761                 cpufreq_debug_enable_ratelimit();
762                 return -EINVAL;
763         }
764         cpufreq_cpu_data[cpu] = NULL;
765
766
767 #ifdef CONFIG_SMP
768         /* if this isn't the CPU which is the parent of the kobj, we
769          * only need to unlink, put and exit
770          */
771         if (unlikely(cpu != data->cpu)) {
772                 dprintk("removing link\n");
773                 cpu_clear(cpu, data->cpus);
774                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
775                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
776                 cpufreq_cpu_put(data);
777                 cpufreq_debug_enable_ratelimit();
778                 return 0;
779         }
780 #endif
781
782
783         if (!kobject_get(&data->kobj)) {
784                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
785                 cpufreq_debug_enable_ratelimit();
786                 return -EFAULT;
787         }
788
789 #ifdef CONFIG_SMP
790         /* if we have other CPUs still registered, we need to unlink them,
791          * or else wait_for_completion below will lock up. Clean the
792          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
793          * links afterwards.
794          */
795         if (unlikely(cpus_weight(data->cpus) > 1)) {
796                 for_each_cpu_mask(j, data->cpus) {
797                         if (j == cpu)
798                                 continue;
799                         cpufreq_cpu_data[j] = NULL;
800                 }
801         }
802
803         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
804
805         if (unlikely(cpus_weight(data->cpus) > 1)) {
806                 for_each_cpu_mask(j, data->cpus) {
807                         if (j == cpu)
808                                 continue;
809                         dprintk("removing link for cpu %u\n", j);
810                         cpu_sys_dev = get_cpu_sysdev(j);
811                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
812                         cpufreq_cpu_put(data);
813                 }
814         }
815 #else
816         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
817 #endif
818
819         mutex_lock(&data->lock);
820         if (cpufreq_driver->target)
821                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
822         mutex_unlock(&data->lock);
823
824         kobject_unregister(&data->kobj);
825
826         kobject_put(&data->kobj);
827
828         /* we need to make sure that the underlying kobj is actually
829          * not referenced anymore by anybody before we proceed with
830          * unloading.
831          */
832         dprintk("waiting for dropping of refcount\n");
833         wait_for_completion(&data->kobj_unregister);
834         dprintk("wait complete\n");
835
836         if (cpufreq_driver->exit)
837                 cpufreq_driver->exit(data);
838
839         kfree(data);
840
841         cpufreq_debug_enable_ratelimit();
842         return 0;
843 }
844
845
846 static void handle_update(void *data)
847 {
848         unsigned int cpu = (unsigned int)(long)data;
849         dprintk("handle_update for cpu %u called\n", cpu);
850         cpufreq_update_policy(cpu);
851 }
852
853 /**
854  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
855  *      @cpu: cpu number
856  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
857  *      @new_freq: CPU frequency the CPU actually runs at
858  *
859  *      We adjust to current frequency first, and need to clean up later. So either call
860  *      to cpufreq_update_policy() or schedule handle_update()).
861  */
862 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
863 {
864         struct cpufreq_freqs freqs;
865
866         dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
867                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
868
869         freqs.cpu = cpu;
870         freqs.old = old_freq;
871         freqs.new = new_freq;
872         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
873         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
874 }
875
876
877 /**
878  * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
879  * @cpu: CPU number
880  *
881  * This is the last known freq, without actually getting it from the driver.
882  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
883  */
884 unsigned int cpufreq_quick_get(unsigned int cpu)
885 {
886         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
887         unsigned int ret = 0;
888
889         if (policy) {
890                 mutex_lock(&policy->lock);
891                 ret = policy->cur;
892                 mutex_unlock(&policy->lock);
893                 cpufreq_cpu_put(policy);
894         }
895
896         return (ret);
897 }
898 EXPORT_SYMBOL(cpufreq_quick_get);
899
900
901 /**
902  * cpufreq_get - get the current CPU frequency (in kHz)
903  * @cpu: CPU number
904  *
905  * Get the CPU current (static) CPU frequency
906  */
907 unsigned int cpufreq_get(unsigned int cpu)
908 {
909         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
910         unsigned int ret = 0;
911
912         if (!policy)
913                 return 0;
914
915         if (!cpufreq_driver->get)
916                 goto out;
917
918         mutex_lock(&policy->lock);
919
920         ret = cpufreq_driver->get(cpu);
921
922         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
923                 /* verify no discrepancy between actual and saved value exists */
924                 if (unlikely(ret != policy->cur)) {
925                         cpufreq_out_of_sync(cpu, policy->cur, ret);
926                         schedule_work(&policy->update);
927                 }
928         }
929
930         mutex_unlock(&policy->lock);
931
932 out:
933         cpufreq_cpu_put(policy);
934
935         return (ret);
936 }
937 EXPORT_SYMBOL(cpufreq_get);
938
939
940 /**
941  *      cpufreq_suspend - let the low level driver prepare for suspend
942  */
943
944 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
945 {
946         int cpu = sysdev->id;
947         unsigned int ret = 0;
948         unsigned int cur_freq = 0;
949         struct cpufreq_policy *cpu_policy;
950
951         dprintk("resuming cpu %u\n", cpu);
952
953         if (!cpu_online(cpu))
954                 return 0;
955
956         /* we may be lax here as interrupts are off. Nonetheless
957          * we need to grab the correct cpu policy, as to check
958          * whether we really run on this CPU.
959          */
960
961         cpu_policy = cpufreq_cpu_get(cpu);
962         if (!cpu_policy)
963                 return -EINVAL;
964
965         /* only handle each CPU group once */
966         if (unlikely(cpu_policy->cpu != cpu)) {
967                 cpufreq_cpu_put(cpu_policy);
968                 return 0;
969         }
970
971         if (cpufreq_driver->suspend) {
972                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
973                 if (ret) {
974                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
975                                         "step on CPU %u\n", cpu_policy->cpu);
976                         cpufreq_cpu_put(cpu_policy);
977                         return ret;
978                 }
979         }
980
981
982         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
983                 goto out;
984
985         if (cpufreq_driver->get)
986                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
987
988         if (!cur_freq || !cpu_policy->cur) {
989                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
990                        "frequency is what timing core thinks it is.\n");
991                 goto out;
992         }
993
994         if (unlikely(cur_freq != cpu_policy->cur)) {
995                 struct cpufreq_freqs freqs;
996
997                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
998                         dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
999                                "cpufreq assumed %u kHz.\n",
1000                                cur_freq, cpu_policy->cur);
1001
1002                 freqs.cpu = cpu;
1003                 freqs.old = cpu_policy->cur;
1004                 freqs.new = cur_freq;
1005
1006                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
1007                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1008                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1009
1010                 cpu_policy->cur = cur_freq;
1011         }
1012
1013 out:
1014         cpufreq_cpu_put(cpu_policy);
1015         return 0;
1016 }
1017
1018 /**
1019  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1020  *
1021  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1022  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1023  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1024  *          restored.
1025  */
1026 static int cpufreq_resume(struct sys_device * sysdev)
1027 {
1028         int cpu = sysdev->id;
1029         unsigned int ret = 0;
1030         struct cpufreq_policy *cpu_policy;
1031
1032         dprintk("resuming cpu %u\n", cpu);
1033
1034         if (!cpu_online(cpu))
1035                 return 0;
1036
1037         /* we may be lax here as interrupts are off. Nonetheless
1038          * we need to grab the correct cpu policy, as to check
1039          * whether we really run on this CPU.
1040          */
1041
1042         cpu_policy = cpufreq_cpu_get(cpu);
1043         if (!cpu_policy)
1044                 return -EINVAL;
1045
1046         /* only handle each CPU group once */
1047         if (unlikely(cpu_policy->cpu != cpu)) {
1048                 cpufreq_cpu_put(cpu_policy);
1049                 return 0;
1050         }
1051
1052         if (cpufreq_driver->resume) {
1053                 ret = cpufreq_driver->resume(cpu_policy);
1054                 if (ret) {
1055                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1056                                         "step on CPU %u\n", cpu_policy->cpu);
1057                         cpufreq_cpu_put(cpu_policy);
1058                         return ret;
1059                 }
1060         }
1061
1062         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1063                 unsigned int cur_freq = 0;
1064
1065                 if (cpufreq_driver->get)
1066                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1067
1068                 if (!cur_freq || !cpu_policy->cur) {
1069                         printk(KERN_ERR "cpufreq: resume failed to assert "
1070                                         "current frequency is what timing core "
1071                                         "thinks it is.\n");
1072                         goto out;
1073                 }
1074
1075                 if (unlikely(cur_freq != cpu_policy->cur)) {
1076                         struct cpufreq_freqs freqs;
1077
1078                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1079                                 dprintk(KERN_WARNING "Warning: CPU frequency"
1080                                        "is %u, cpufreq assumed %u kHz.\n",
1081                                        cur_freq, cpu_policy->cur);
1082
1083                         freqs.cpu = cpu;
1084                         freqs.old = cpu_policy->cur;
1085                         freqs.new = cur_freq;
1086
1087                         blocking_notifier_call_chain(
1088                                         &cpufreq_transition_notifier_list,
1089                                         CPUFREQ_RESUMECHANGE, &freqs);
1090                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1091
1092                         cpu_policy->cur = cur_freq;
1093                 }
1094         }
1095
1096 out:
1097         schedule_work(&cpu_policy->update);
1098         cpufreq_cpu_put(cpu_policy);
1099         return ret;
1100 }
1101
1102 static struct sysdev_driver cpufreq_sysdev_driver = {
1103         .add            = cpufreq_add_dev,
1104         .remove         = cpufreq_remove_dev,
1105         .suspend        = cpufreq_suspend,
1106         .resume         = cpufreq_resume,
1107 };
1108
1109
1110 /*********************************************************************
1111  *                     NOTIFIER LISTS INTERFACE                      *
1112  *********************************************************************/
1113
1114 /**
1115  *      cpufreq_register_notifier - register a driver with cpufreq
1116  *      @nb: notifier function to register
1117  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1118  *
1119  *      Add a driver to one of two lists: either a list of drivers that
1120  *      are notified about clock rate changes (once before and once after
1121  *      the transition), or a list of drivers that are notified about
1122  *      changes in cpufreq policy.
1123  *
1124  *      This function may sleep, and has the same return conditions as
1125  *      blocking_notifier_chain_register.
1126  */
1127 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1128 {
1129         int ret;
1130
1131         switch (list) {
1132         case CPUFREQ_TRANSITION_NOTIFIER:
1133                 ret = blocking_notifier_chain_register(
1134                                 &cpufreq_transition_notifier_list, nb);
1135                 break;
1136         case CPUFREQ_POLICY_NOTIFIER:
1137                 ret = blocking_notifier_chain_register(
1138                                 &cpufreq_policy_notifier_list, nb);
1139                 break;
1140         default:
1141                 ret = -EINVAL;
1142         }
1143
1144         return ret;
1145 }
1146 EXPORT_SYMBOL(cpufreq_register_notifier);
1147
1148
1149 /**
1150  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1151  *      @nb: notifier block to be unregistered
1152  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1153  *
1154  *      Remove a driver from the CPU frequency notifier list.
1155  *
1156  *      This function may sleep, and has the same return conditions as
1157  *      blocking_notifier_chain_unregister.
1158  */
1159 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1160 {
1161         int ret;
1162
1163         switch (list) {
1164         case CPUFREQ_TRANSITION_NOTIFIER:
1165                 ret = blocking_notifier_chain_unregister(
1166                                 &cpufreq_transition_notifier_list, nb);
1167                 break;
1168         case CPUFREQ_POLICY_NOTIFIER:
1169                 ret = blocking_notifier_chain_unregister(
1170                                 &cpufreq_policy_notifier_list, nb);
1171                 break;
1172         default:
1173                 ret = -EINVAL;
1174         }
1175
1176         return ret;
1177 }
1178 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1179
1180
1181 /*********************************************************************
1182  *                              GOVERNORS                            *
1183  *********************************************************************/
1184
1185
1186 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1187                             unsigned int target_freq,
1188                             unsigned int relation)
1189 {
1190         int retval = -EINVAL;
1191
1192         lock_cpu_hotplug();
1193         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1194                 target_freq, relation);
1195         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1196                 retval = cpufreq_driver->target(policy, target_freq, relation);
1197
1198         unlock_cpu_hotplug();
1199
1200         return retval;
1201 }
1202 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1203
1204 int cpufreq_driver_target(struct cpufreq_policy *policy,
1205                           unsigned int target_freq,
1206                           unsigned int relation)
1207 {
1208         int ret;
1209
1210         policy = cpufreq_cpu_get(policy->cpu);
1211         if (!policy)
1212                 return -EINVAL;
1213
1214         mutex_lock(&policy->lock);
1215
1216         ret = __cpufreq_driver_target(policy, target_freq, relation);
1217
1218         mutex_unlock(&policy->lock);
1219
1220         cpufreq_cpu_put(policy);
1221         return ret;
1222 }
1223 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1224
1225
1226 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1227 {
1228         int ret;
1229
1230         if (!try_module_get(policy->governor->owner))
1231                 return -EINVAL;
1232
1233         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1234         ret = policy->governor->governor(policy, event);
1235
1236         /* we keep one module reference alive for each CPU governed by this CPU */
1237         if ((event != CPUFREQ_GOV_START) || ret)
1238                 module_put(policy->governor->owner);
1239         if ((event == CPUFREQ_GOV_STOP) && !ret)
1240                 module_put(policy->governor->owner);
1241
1242         return ret;
1243 }
1244
1245
1246 int cpufreq_governor(unsigned int cpu, unsigned int event)
1247 {
1248         int ret = 0;
1249         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1250
1251         if (!policy)
1252                 return -EINVAL;
1253
1254         mutex_lock(&policy->lock);
1255         ret = __cpufreq_governor(policy, event);
1256         mutex_unlock(&policy->lock);
1257
1258         cpufreq_cpu_put(policy);
1259         return ret;
1260 }
1261 EXPORT_SYMBOL_GPL(cpufreq_governor);
1262
1263
1264 int cpufreq_register_governor(struct cpufreq_governor *governor)
1265 {
1266         struct cpufreq_governor *t;
1267
1268         if (!governor)
1269                 return -EINVAL;
1270
1271         mutex_lock(&cpufreq_governor_mutex);
1272
1273         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1274                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1275                         mutex_unlock(&cpufreq_governor_mutex);
1276                         return -EBUSY;
1277                 }
1278         }
1279         list_add(&governor->governor_list, &cpufreq_governor_list);
1280
1281         mutex_unlock(&cpufreq_governor_mutex);
1282         return 0;
1283 }
1284 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1285
1286
1287 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1288 {
1289         if (!governor)
1290                 return;
1291
1292         mutex_lock(&cpufreq_governor_mutex);
1293         list_del(&governor->governor_list);
1294         mutex_unlock(&cpufreq_governor_mutex);
1295         return;
1296 }
1297 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1298
1299
1300
1301 /*********************************************************************
1302  *                          POLICY INTERFACE                         *
1303  *********************************************************************/
1304
1305 /**
1306  * cpufreq_get_policy - get the current cpufreq_policy
1307  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1308  *
1309  * Reads the current cpufreq policy.
1310  */
1311 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1312 {
1313         struct cpufreq_policy *cpu_policy;
1314         if (!policy)
1315                 return -EINVAL;
1316
1317         cpu_policy = cpufreq_cpu_get(cpu);
1318         if (!cpu_policy)
1319                 return -EINVAL;
1320
1321         mutex_lock(&cpu_policy->lock);
1322         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1323         mutex_unlock(&cpu_policy->lock);
1324
1325         cpufreq_cpu_put(cpu_policy);
1326         return 0;
1327 }
1328 EXPORT_SYMBOL(cpufreq_get_policy);
1329
1330
1331 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1332 {
1333         int ret = 0;
1334
1335         cpufreq_debug_disable_ratelimit();
1336         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1337                 policy->min, policy->max);
1338
1339         memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo));
1340
1341         /* verify the cpu speed can be set within this limit */
1342         ret = cpufreq_driver->verify(policy);
1343         if (ret)
1344                 goto error_out;
1345
1346         /* adjust if necessary - all reasons */
1347         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1348                         CPUFREQ_ADJUST, policy);
1349
1350         /* adjust if necessary - hardware incompatibility*/
1351         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1352                         CPUFREQ_INCOMPATIBLE, policy);
1353
1354         /* verify the cpu speed can be set within this limit,
1355            which might be different to the first one */
1356         ret = cpufreq_driver->verify(policy);
1357         if (ret)
1358                 goto error_out;
1359
1360         /* notification of the new policy */
1361         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1362                         CPUFREQ_NOTIFY, policy);
1363
1364         data->min = policy->min;
1365         data->max = policy->max;
1366
1367         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1368
1369         if (cpufreq_driver->setpolicy) {
1370                 data->policy = policy->policy;
1371                 dprintk("setting range\n");
1372                 ret = cpufreq_driver->setpolicy(policy);
1373         } else {
1374                 if (policy->governor != data->governor) {
1375                         /* save old, working values */
1376                         struct cpufreq_governor *old_gov = data->governor;
1377
1378                         dprintk("governor switch\n");
1379
1380                         /* end old governor */
1381                         if (data->governor)
1382                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1383
1384                         /* start new governor */
1385                         data->governor = policy->governor;
1386                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1387                                 /* new governor failed, so re-start old one */
1388                                 dprintk("starting governor %s failed\n", data->governor->name);
1389                                 if (old_gov) {
1390                                         data->governor = old_gov;
1391                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1392                                 }
1393                                 ret = -EINVAL;
1394                                 goto error_out;
1395                         }
1396                         /* might be a policy change, too, so fall through */
1397                 }
1398                 dprintk("governor: change or update limits\n");
1399                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1400         }
1401
1402 error_out:
1403         cpufreq_debug_enable_ratelimit();
1404         return ret;
1405 }
1406
1407 /**
1408  *      cpufreq_set_policy - set a new CPUFreq policy
1409  *      @policy: policy to be set.
1410  *
1411  *      Sets a new CPU frequency and voltage scaling policy.
1412  */
1413 int cpufreq_set_policy(struct cpufreq_policy *policy)
1414 {
1415         int ret = 0;
1416         struct cpufreq_policy *data;
1417
1418         if (!policy)
1419                 return -EINVAL;
1420
1421         data = cpufreq_cpu_get(policy->cpu);
1422         if (!data)
1423                 return -EINVAL;
1424
1425         /* lock this CPU */
1426         mutex_lock(&data->lock);
1427
1428         ret = __cpufreq_set_policy(data, policy);
1429         data->user_policy.min = data->min;
1430         data->user_policy.max = data->max;
1431         data->user_policy.policy = data->policy;
1432         data->user_policy.governor = data->governor;
1433
1434         mutex_unlock(&data->lock);
1435         cpufreq_cpu_put(data);
1436
1437         return ret;
1438 }
1439 EXPORT_SYMBOL(cpufreq_set_policy);
1440
1441
1442 /**
1443  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1444  *      @cpu: CPU which shall be re-evaluated
1445  *
1446  *      Usefull for policy notifiers which have different necessities
1447  *      at different times.
1448  */
1449 int cpufreq_update_policy(unsigned int cpu)
1450 {
1451         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1452         struct cpufreq_policy policy;
1453         int ret = 0;
1454
1455         if (!data)
1456                 return -ENODEV;
1457
1458         mutex_lock(&data->lock);
1459
1460         dprintk("updating policy for CPU %u\n", cpu);
1461         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1462         policy.min = data->user_policy.min;
1463         policy.max = data->user_policy.max;
1464         policy.policy = data->user_policy.policy;
1465         policy.governor = data->user_policy.governor;
1466
1467         /* BIOS might change freq behind our back
1468           -> ask driver for current freq and notify governors about a change */
1469         if (cpufreq_driver->get) {
1470                 policy.cur = cpufreq_driver->get(cpu);
1471                 if (!data->cur) {
1472                         dprintk("Driver did not initialize current freq");
1473                         data->cur = policy.cur;
1474                 } else {
1475                         if (data->cur != policy.cur)
1476                                 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1477                 }
1478         }
1479
1480         ret = __cpufreq_set_policy(data, &policy);
1481
1482         mutex_unlock(&data->lock);
1483
1484         cpufreq_cpu_put(data);
1485         return ret;
1486 }
1487 EXPORT_SYMBOL(cpufreq_update_policy);
1488
1489 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1490                                         unsigned long action, void *hcpu)
1491 {
1492         unsigned int cpu = (unsigned long)hcpu;
1493         struct cpufreq_policy *policy;
1494         struct sys_device *sys_dev;
1495
1496         sys_dev = get_cpu_sysdev(cpu);
1497
1498         if (sys_dev) {
1499                 switch (action) {
1500                 case CPU_ONLINE:
1501                         cpufreq_add_dev(sys_dev);
1502                         break;
1503                 case CPU_DOWN_PREPARE:
1504                         /*
1505                          * We attempt to put this cpu in lowest frequency
1506                          * possible before going down. This will permit
1507                          * hardware-managed P-State to switch other related
1508                          * threads to min or higher speeds if possible.
1509                          */
1510                         policy = cpufreq_cpu_data[cpu];
1511                         if (policy) {
1512                                 cpufreq_driver_target(policy, policy->min,
1513                                                 CPUFREQ_RELATION_H);
1514                         }
1515                         break;
1516                 case CPU_DEAD:
1517                         cpufreq_remove_dev(sys_dev);
1518                         break;
1519                 }
1520         }
1521         return NOTIFY_OK;
1522 }
1523
1524 static struct notifier_block cpufreq_cpu_notifier =
1525 {
1526     .notifier_call = cpufreq_cpu_callback,
1527 };
1528
1529 /*********************************************************************
1530  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1531  *********************************************************************/
1532
1533 /**
1534  * cpufreq_register_driver - register a CPU Frequency driver
1535  * @driver_data: A struct cpufreq_driver containing the values#
1536  * submitted by the CPU Frequency driver.
1537  *
1538  *   Registers a CPU Frequency driver to this core code. This code
1539  * returns zero on success, -EBUSY when another driver got here first
1540  * (and isn't unregistered in the meantime).
1541  *
1542  */
1543 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1544 {
1545         unsigned long flags;
1546         int ret;
1547
1548         if (!driver_data || !driver_data->verify || !driver_data->init ||
1549             ((!driver_data->setpolicy) && (!driver_data->target)))
1550                 return -EINVAL;
1551
1552         dprintk("trying to register driver %s\n", driver_data->name);
1553
1554         if (driver_data->setpolicy)
1555                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1556
1557         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1558         if (cpufreq_driver) {
1559                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1560                 return -EBUSY;
1561         }
1562         cpufreq_driver = driver_data;
1563         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1564
1565         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1566
1567         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1568                 int i;
1569                 ret = -ENODEV;
1570
1571                 /* check for at least one working CPU */
1572                 for (i=0; i<NR_CPUS; i++)
1573                         if (cpufreq_cpu_data[i])
1574                                 ret = 0;
1575
1576                 /* if all ->init() calls failed, unregister */
1577                 if (ret) {
1578                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1579                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1580
1581                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1582                         cpufreq_driver = NULL;
1583                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1584                 }
1585         }
1586
1587         if (!ret) {
1588                 register_cpu_notifier(&cpufreq_cpu_notifier);
1589                 dprintk("driver %s up and running\n", driver_data->name);
1590                 cpufreq_debug_enable_ratelimit();
1591         }
1592
1593         return (ret);
1594 }
1595 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1596
1597
1598 /**
1599  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1600  *
1601  *    Unregister the current CPUFreq driver. Only call this if you have
1602  * the right to do so, i.e. if you have succeeded in initialising before!
1603  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1604  * currently not initialised.
1605  */
1606 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1607 {
1608         unsigned long flags;
1609
1610         cpufreq_debug_disable_ratelimit();
1611
1612         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1613                 cpufreq_debug_enable_ratelimit();
1614                 return -EINVAL;
1615         }
1616
1617         dprintk("unregistering driver %s\n", driver->name);
1618
1619         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1620         unregister_cpu_notifier(&cpufreq_cpu_notifier);
1621
1622         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1623         cpufreq_driver = NULL;
1624         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1625
1626         return 0;
1627 }
1628 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);