Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/i2c-2.6
[linux-2.6] / 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  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  *
14  */
15
16 #include <linux/config.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/notifier.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/interrupt.h>
24 #include <linux/spinlock.h>
25 #include <linux/device.h>
26 #include <linux/slab.h>
27 #include <linux/cpu.h>
28 #include <linux/completion.h>
29 #include <linux/mutex.h>
30
31 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
32
33 /**
34  * The "cpufreq driver" - the arch- or hardware-dependend low
35  * level driver of CPUFreq support, and its spinlock. This lock
36  * also protects the cpufreq_cpu_data array.
37  */
38 static struct cpufreq_driver *cpufreq_driver;
39 static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
40 static DEFINE_SPINLOCK(cpufreq_driver_lock);
41
42 /* internal prototypes */
43 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
44 static void handle_update(void *data);
45
46 /**
47  * Two notifier lists: the "policy" list is involved in the 
48  * validation process for a new CPU frequency policy; the 
49  * "transition" list for kernel code that needs to handle
50  * changes to devices when the CPU clock speed changes.
51  * The mutex locks both lists.
52  */
53 static struct notifier_block *cpufreq_policy_notifier_list;
54 static struct notifier_block *cpufreq_transition_notifier_list;
55 static DECLARE_RWSEM (cpufreq_notifier_rwsem);
56
57
58 static LIST_HEAD(cpufreq_governor_list);
59 static DEFINE_MUTEX (cpufreq_governor_mutex);
60
61 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
62 {
63         struct cpufreq_policy *data;
64         unsigned long flags;
65
66         if (cpu >= NR_CPUS)
67                 goto err_out;
68
69         /* get the cpufreq driver */
70         spin_lock_irqsave(&cpufreq_driver_lock, flags);
71
72         if (!cpufreq_driver)
73                 goto err_out_unlock;
74
75         if (!try_module_get(cpufreq_driver->owner))
76                 goto err_out_unlock;
77
78
79         /* get the CPU */
80         data = cpufreq_cpu_data[cpu];
81
82         if (!data)
83                 goto err_out_put_module;
84
85         if (!kobject_get(&data->kobj))
86                 goto err_out_put_module;
87
88         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
89         return data;
90
91 err_out_put_module:
92         module_put(cpufreq_driver->owner);
93 err_out_unlock:
94         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
95 err_out:
96         return NULL;
97 }
98 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
99
100
101 void cpufreq_cpu_put(struct cpufreq_policy *data)
102 {
103         kobject_put(&data->kobj);
104         module_put(cpufreq_driver->owner);
105 }
106 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
107
108
109 /*********************************************************************
110  *                     UNIFIED DEBUG HELPERS                         *
111  *********************************************************************/
112 #ifdef CONFIG_CPU_FREQ_DEBUG
113
114 /* what part(s) of the CPUfreq subsystem are debugged? */
115 static unsigned int debug;
116
117 /* is the debug output ratelimit'ed using printk_ratelimit? User can
118  * set or modify this value.
119  */
120 static unsigned int debug_ratelimit = 1;
121
122 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
123  * loading of a cpufreq driver, temporarily disabled when a new policy
124  * is set, and disabled upon cpufreq driver removal
125  */
126 static unsigned int disable_ratelimit = 1;
127 static DEFINE_SPINLOCK(disable_ratelimit_lock);
128
129 static void cpufreq_debug_enable_ratelimit(void)
130 {
131         unsigned long flags;
132
133         spin_lock_irqsave(&disable_ratelimit_lock, flags);
134         if (disable_ratelimit)
135                 disable_ratelimit--;
136         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
137 }
138
139 static void cpufreq_debug_disable_ratelimit(void)
140 {
141         unsigned long flags;
142
143         spin_lock_irqsave(&disable_ratelimit_lock, flags);
144         disable_ratelimit++;
145         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
146 }
147
148 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
149 {
150         char s[256];
151         va_list args;
152         unsigned int len;
153         unsigned long flags;
154         
155         WARN_ON(!prefix);
156         if (type & debug) {
157                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
158                 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
159                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
160                         return;
161                 }
162                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
163
164                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
165
166                 va_start(args, fmt);
167                 len += vsnprintf(&s[len], (256 - len), fmt, args);
168                 va_end(args);
169
170                 printk(s);
171
172                 WARN_ON(len < 5);
173         }
174 }
175 EXPORT_SYMBOL(cpufreq_debug_printk);
176
177
178 module_param(debug, uint, 0644);
179 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
180
181 module_param(debug_ratelimit, uint, 0644);
182 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
183
184 #else /* !CONFIG_CPU_FREQ_DEBUG */
185
186 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
187 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
188
189 #endif /* CONFIG_CPU_FREQ_DEBUG */
190
191
192 /*********************************************************************
193  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
194  *********************************************************************/
195
196 /**
197  * adjust_jiffies - adjust the system "loops_per_jiffy"
198  *
199  * This function alters the system "loops_per_jiffy" for the clock
200  * speed change. Note that loops_per_jiffy cannot be updated on SMP
201  * systems as each CPU might be scaled differently. So, use the arch 
202  * per-CPU loops_per_jiffy value wherever possible.
203  */
204 #ifndef CONFIG_SMP
205 static unsigned long l_p_j_ref;
206 static unsigned int  l_p_j_ref_freq;
207
208 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
209 {
210         if (ci->flags & CPUFREQ_CONST_LOOPS)
211                 return;
212
213         if (!l_p_j_ref_freq) {
214                 l_p_j_ref = loops_per_jiffy;
215                 l_p_j_ref_freq = ci->old;
216                 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
217         }
218         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
219             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
220             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
221                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
222                 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
223         }
224 }
225 #else
226 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
227 #endif
228
229
230 /**
231  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
232  * on frequency transition.
233  *
234  * This function calls the transition notifiers and the "adjust_jiffies"
235  * function. It is called twice on all CPU frequency changes that have
236  * external effects. 
237  */
238 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
239 {
240         struct cpufreq_policy *policy;
241
242         BUG_ON(irqs_disabled());
243
244         freqs->flags = cpufreq_driver->flags;
245         dprintk("notification %u of frequency transition to %u kHz\n",
246                 state, freqs->new);
247
248         down_read(&cpufreq_notifier_rwsem);
249
250         policy = cpufreq_cpu_data[freqs->cpu];
251         switch (state) {
252
253         case CPUFREQ_PRECHANGE:
254                 /* detect if the driver reported a value as "old frequency" 
255                  * which is not equal to what the cpufreq core thinks is
256                  * "old frequency".
257                  */
258                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
259                         if ((policy) && (policy->cpu == freqs->cpu) &&
260                             (policy->cur) && (policy->cur != freqs->old)) {
261                                 dprintk(KERN_WARNING "Warning: CPU frequency is"
262                                         " %u, cpufreq assumed %u kHz.\n",
263                                         freqs->old, policy->cur);
264                                 freqs->old = policy->cur;
265                         }
266                 }
267                 notifier_call_chain(&cpufreq_transition_notifier_list,
268                                         CPUFREQ_PRECHANGE, freqs);
269                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
270                 break;
271
272         case CPUFREQ_POSTCHANGE:
273                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
274                 notifier_call_chain(&cpufreq_transition_notifier_list,
275                                         CPUFREQ_POSTCHANGE, freqs);
276                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
277                         policy->cur = freqs->new;
278                 break;
279         }
280         up_read(&cpufreq_notifier_rwsem);
281 }
282 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
283
284
285
286 /*********************************************************************
287  *                          SYSFS INTERFACE                          *
288  *********************************************************************/
289
290 /**
291  * cpufreq_parse_governor - parse a governor string
292  */
293 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
294                                 struct cpufreq_governor **governor)
295 {
296         if (!cpufreq_driver)
297                 return -EINVAL;
298         if (cpufreq_driver->setpolicy) {
299                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
300                         *policy = CPUFREQ_POLICY_PERFORMANCE;
301                         return 0;
302                 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
303                         *policy = CPUFREQ_POLICY_POWERSAVE;
304                         return 0;
305                 }
306                 return -EINVAL;
307         } else {
308                 struct cpufreq_governor *t;
309                 mutex_lock(&cpufreq_governor_mutex);
310                 if (!cpufreq_driver || !cpufreq_driver->target)
311                         goto out;
312                 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
313                         if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
314                                 *governor = t;
315                                 mutex_unlock(&cpufreq_governor_mutex);
316                                 return 0;
317                         }
318                 }
319 out:
320                 mutex_unlock(&cpufreq_governor_mutex);
321         }
322         return -EINVAL;
323 }
324 EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
325
326
327 /* drivers/base/cpu.c */
328 extern struct sysdev_class cpu_sysdev_class;
329
330
331 /**
332  * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
333  *
334  * Write out information from cpufreq_driver->policy[cpu]; object must be
335  * "unsigned int".
336  */
337
338 #define show_one(file_name, object)                                     \
339 static ssize_t show_##file_name                                         \
340 (struct cpufreq_policy * policy, char *buf)                             \
341 {                                                                       \
342         return sprintf (buf, "%u\n", policy->object);                   \
343 }
344
345 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
346 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
347 show_one(scaling_min_freq, min);
348 show_one(scaling_max_freq, max);
349 show_one(scaling_cur_freq, cur);
350
351 /**
352  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
353  */
354 #define store_one(file_name, object)                    \
355 static ssize_t store_##file_name                                        \
356 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
357 {                                                                       \
358         unsigned int ret = -EINVAL;                                     \
359         struct cpufreq_policy new_policy;                               \
360                                                                         \
361         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
362         if (ret)                                                        \
363                 return -EINVAL;                                         \
364                                                                         \
365         ret = sscanf (buf, "%u", &new_policy.object);                   \
366         if (ret != 1)                                                   \
367                 return -EINVAL;                                         \
368                                                                         \
369         ret = cpufreq_set_policy(&new_policy);                          \
370                                                                         \
371         return ret ? ret : count;                                       \
372 }
373
374 store_one(scaling_min_freq,min);
375 store_one(scaling_max_freq,max);
376
377 /**
378  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
379  */
380 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
381 {
382         unsigned int cur_freq = cpufreq_get(policy->cpu);
383         if (!cur_freq)
384                 return sprintf(buf, "<unknown>");
385         return sprintf(buf, "%u\n", cur_freq);
386 }
387
388
389 /**
390  * show_scaling_governor - show the current policy for the specified CPU
391  */
392 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
393 {
394         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
395                 return sprintf(buf, "powersave\n");
396         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
397                 return sprintf(buf, "performance\n");
398         else if (policy->governor)
399                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
400         return -EINVAL;
401 }
402
403
404 /**
405  * store_scaling_governor - store policy for the specified CPU
406  */
407 static ssize_t store_scaling_governor (struct cpufreq_policy * policy, 
408                                        const char *buf, size_t count) 
409 {
410         unsigned int ret = -EINVAL;
411         char    str_governor[16];
412         struct cpufreq_policy new_policy;
413
414         ret = cpufreq_get_policy(&new_policy, policy->cpu);
415         if (ret)
416                 return ret;
417
418         ret = sscanf (buf, "%15s", str_governor);
419         if (ret != 1)
420                 return -EINVAL;
421
422         if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
423                 return -EINVAL;
424
425         ret = cpufreq_set_policy(&new_policy);
426         return ret ? ret : count;
427 }
428
429 /**
430  * show_scaling_driver - show the cpufreq driver currently loaded
431  */
432 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
433 {
434         return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
435 }
436
437 /**
438  * show_scaling_available_governors - show the available CPUfreq governors
439  */
440 static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
441                                 char *buf)
442 {
443         ssize_t i = 0;
444         struct cpufreq_governor *t;
445
446         if (!cpufreq_driver->target) {
447                 i += sprintf(buf, "performance powersave");
448                 goto out;
449         }
450
451         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
452                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
453                         goto out;
454                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
455         }
456 out:
457         i += sprintf(&buf[i], "\n");
458         return i;
459 }
460 /**
461  * show_affected_cpus - show the CPUs affected by each transition
462  */
463 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
464 {
465         ssize_t i = 0;
466         unsigned int cpu;
467
468         for_each_cpu_mask(cpu, policy->cpus) {
469                 if (i)
470                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
471                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
472                 if (i >= (PAGE_SIZE - 5))
473                     break;
474         }
475         i += sprintf(&buf[i], "\n");
476         return i;
477 }
478
479
480 #define define_one_ro(_name) \
481 static struct freq_attr _name = \
482 __ATTR(_name, 0444, show_##_name, NULL)
483
484 #define define_one_ro0400(_name) \
485 static struct freq_attr _name = \
486 __ATTR(_name, 0400, show_##_name, NULL)
487
488 #define define_one_rw(_name) \
489 static struct freq_attr _name = \
490 __ATTR(_name, 0644, show_##_name, store_##_name)
491
492 define_one_ro0400(cpuinfo_cur_freq);
493 define_one_ro(cpuinfo_min_freq);
494 define_one_ro(cpuinfo_max_freq);
495 define_one_ro(scaling_available_governors);
496 define_one_ro(scaling_driver);
497 define_one_ro(scaling_cur_freq);
498 define_one_ro(affected_cpus);
499 define_one_rw(scaling_min_freq);
500 define_one_rw(scaling_max_freq);
501 define_one_rw(scaling_governor);
502
503 static struct attribute * default_attrs[] = {
504         &cpuinfo_min_freq.attr,
505         &cpuinfo_max_freq.attr,
506         &scaling_min_freq.attr,
507         &scaling_max_freq.attr,
508         &affected_cpus.attr,
509         &scaling_governor.attr,
510         &scaling_driver.attr,
511         &scaling_available_governors.attr,
512         NULL
513 };
514
515 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
516 #define to_attr(a) container_of(a,struct freq_attr,attr)
517
518 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
519 {
520         struct cpufreq_policy * policy = to_policy(kobj);
521         struct freq_attr * fattr = to_attr(attr);
522         ssize_t ret;
523         policy = cpufreq_cpu_get(policy->cpu);
524         if (!policy)
525                 return -EINVAL;
526         ret = fattr->show ? fattr->show(policy,buf) : -EIO;
527         cpufreq_cpu_put(policy);
528         return ret;
529 }
530
531 static ssize_t store(struct kobject * kobj, struct attribute * attr, 
532                      const char * buf, size_t count)
533 {
534         struct cpufreq_policy * policy = to_policy(kobj);
535         struct freq_attr * fattr = to_attr(attr);
536         ssize_t ret;
537         policy = cpufreq_cpu_get(policy->cpu);
538         if (!policy)
539                 return -EINVAL;
540         ret = fattr->store ? fattr->store(policy,buf,count) : -EIO;
541         cpufreq_cpu_put(policy);
542         return ret;
543 }
544
545 static void cpufreq_sysfs_release(struct kobject * kobj)
546 {
547         struct cpufreq_policy * policy = to_policy(kobj);
548         dprintk("last reference is dropped\n");
549         complete(&policy->kobj_unregister);
550 }
551
552 static struct sysfs_ops sysfs_ops = {
553         .show   = show,
554         .store  = store,
555 };
556
557 static struct kobj_type ktype_cpufreq = {
558         .sysfs_ops      = &sysfs_ops,
559         .default_attrs  = default_attrs,
560         .release        = cpufreq_sysfs_release,
561 };
562
563
564 /**
565  * cpufreq_add_dev - add a CPU device
566  *
567  * Adds the cpufreq interface for a CPU device. 
568  */
569 static int cpufreq_add_dev (struct sys_device * sys_dev)
570 {
571         unsigned int cpu = sys_dev->id;
572         int ret = 0;
573         struct cpufreq_policy new_policy;
574         struct cpufreq_policy *policy;
575         struct freq_attr **drv_attr;
576         unsigned long flags;
577         unsigned int j;
578
579         if (cpu_is_offline(cpu))
580                 return 0;
581
582         cpufreq_debug_disable_ratelimit();
583         dprintk("adding CPU %u\n", cpu);
584
585 #ifdef CONFIG_SMP
586         /* check whether a different CPU already registered this
587          * CPU because it is in the same boat. */
588         policy = cpufreq_cpu_get(cpu);
589         if (unlikely(policy)) {
590                 dprintk("CPU already managed, adding link\n");
591                 sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
592                 cpufreq_debug_enable_ratelimit();
593                 return 0;
594         }
595 #endif
596
597         if (!try_module_get(cpufreq_driver->owner)) {
598                 ret = -EINVAL;
599                 goto module_out;
600         }
601
602         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
603         if (!policy) {
604                 ret = -ENOMEM;
605                 goto nomem_out;
606         }
607
608         policy->cpu = cpu;
609         policy->cpus = cpumask_of_cpu(cpu);
610
611         mutex_init(&policy->lock);
612         mutex_lock(&policy->lock);
613         init_completion(&policy->kobj_unregister);
614         INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
615
616         /* call driver. From then on the cpufreq must be able
617          * to accept all calls to ->verify and ->setpolicy for this CPU
618          */
619         ret = cpufreq_driver->init(policy);
620         if (ret) {
621                 dprintk("initialization failed\n");
622                 mutex_unlock(&policy->lock);
623                 goto err_out;
624         }
625
626         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
627
628         /* prepare interface data */
629         policy->kobj.parent = &sys_dev->kobj;
630         policy->kobj.ktype = &ktype_cpufreq;
631         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
632
633         ret = kobject_register(&policy->kobj);
634         if (ret) {
635                 mutex_unlock(&policy->lock);
636                 goto err_out_driver_exit;
637         }
638         /* set up files for this cpu device */
639         drv_attr = cpufreq_driver->attr;
640         while ((drv_attr) && (*drv_attr)) {
641                 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
642                 drv_attr++;
643         }
644         if (cpufreq_driver->get)
645                 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
646         if (cpufreq_driver->target)
647                 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
648
649         spin_lock_irqsave(&cpufreq_driver_lock, flags);
650         for_each_cpu_mask(j, policy->cpus)
651                 cpufreq_cpu_data[j] = policy;
652         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
653         policy->governor = NULL; /* to assure that the starting sequence is
654                                   * run in cpufreq_set_policy */
655         mutex_unlock(&policy->lock);
656         
657         /* set default policy */
658         
659         ret = cpufreq_set_policy(&new_policy);
660         if (ret) {
661                 dprintk("setting policy failed\n");
662                 goto err_out_unregister;
663         }
664
665         module_put(cpufreq_driver->owner);
666         dprintk("initialization complete\n");
667         cpufreq_debug_enable_ratelimit();
668         
669         return 0;
670
671
672 err_out_unregister:
673         spin_lock_irqsave(&cpufreq_driver_lock, flags);
674         for_each_cpu_mask(j, policy->cpus)
675                 cpufreq_cpu_data[j] = NULL;
676         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
677
678         kobject_unregister(&policy->kobj);
679         wait_for_completion(&policy->kobj_unregister);
680
681 err_out_driver_exit:
682         if (cpufreq_driver->exit)
683                 cpufreq_driver->exit(policy);
684
685 err_out:
686         kfree(policy);
687
688 nomem_out:
689         module_put(cpufreq_driver->owner);
690 module_out:
691         cpufreq_debug_enable_ratelimit();
692         return ret;
693 }
694
695
696 /**
697  * cpufreq_remove_dev - remove a CPU device
698  *
699  * Removes the cpufreq interface for a CPU device.
700  */
701 static int cpufreq_remove_dev (struct sys_device * sys_dev)
702 {
703         unsigned int cpu = sys_dev->id;
704         unsigned long flags;
705         struct cpufreq_policy *data;
706 #ifdef CONFIG_SMP
707         struct sys_device *cpu_sys_dev;
708         unsigned int j;
709 #endif
710
711         cpufreq_debug_disable_ratelimit();
712         dprintk("unregistering CPU %u\n", cpu);
713
714         spin_lock_irqsave(&cpufreq_driver_lock, flags);
715         data = cpufreq_cpu_data[cpu];
716
717         if (!data) {
718                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
719                 cpufreq_debug_enable_ratelimit();
720                 return -EINVAL;
721         }
722         cpufreq_cpu_data[cpu] = NULL;
723
724
725 #ifdef CONFIG_SMP
726         /* if this isn't the CPU which is the parent of the kobj, we
727          * only need to unlink, put and exit 
728          */
729         if (unlikely(cpu != data->cpu)) {
730                 dprintk("removing link\n");
731                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
732                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
733                 cpufreq_cpu_put(data);
734                 cpufreq_debug_enable_ratelimit();
735                 return 0;
736         }
737 #endif
738
739
740         if (!kobject_get(&data->kobj)) {
741                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
742                 cpufreq_debug_enable_ratelimit();
743                 return -EFAULT;
744         }
745
746 #ifdef CONFIG_SMP
747         /* if we have other CPUs still registered, we need to unlink them,
748          * or else wait_for_completion below will lock up. Clean the
749          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
750          * links afterwards.
751          */
752         if (unlikely(cpus_weight(data->cpus) > 1)) {
753                 for_each_cpu_mask(j, data->cpus) {
754                         if (j == cpu)
755                                 continue;
756                         cpufreq_cpu_data[j] = NULL;
757                 }
758         }
759
760         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
761
762         if (unlikely(cpus_weight(data->cpus) > 1)) {
763                 for_each_cpu_mask(j, data->cpus) {
764                         if (j == cpu)
765                                 continue;
766                         dprintk("removing link for cpu %u\n", j);
767                         cpu_sys_dev = get_cpu_sysdev(j);
768                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
769                         cpufreq_cpu_put(data);
770                 }
771         }
772 #else
773         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
774 #endif
775
776         mutex_lock(&data->lock);
777         if (cpufreq_driver->target)
778                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
779         mutex_unlock(&data->lock);
780
781         kobject_unregister(&data->kobj);
782
783         kobject_put(&data->kobj);
784
785         /* we need to make sure that the underlying kobj is actually
786          * not referenced anymore by anybody before we proceed with 
787          * unloading.
788          */
789         dprintk("waiting for dropping of refcount\n");
790         wait_for_completion(&data->kobj_unregister);
791         dprintk("wait complete\n");
792
793         if (cpufreq_driver->exit)
794                 cpufreq_driver->exit(data);
795
796         kfree(data);
797
798         cpufreq_debug_enable_ratelimit();
799         return 0;
800 }
801
802
803 static void handle_update(void *data)
804 {
805         unsigned int cpu = (unsigned int)(long)data;
806         dprintk("handle_update for cpu %u called\n", cpu);
807         cpufreq_update_policy(cpu);
808 }
809
810 /**
811  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
812  *      @cpu: cpu number
813  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
814  *      @new_freq: CPU frequency the CPU actually runs at
815  *
816  *      We adjust to current frequency first, and need to clean up later. So either call
817  *      to cpufreq_update_policy() or schedule handle_update()).
818  */
819 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
820 {
821         struct cpufreq_freqs freqs;
822
823         dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
824                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
825
826         freqs.cpu = cpu;
827         freqs.old = old_freq;
828         freqs.new = new_freq;
829         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
830         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
831 }
832
833
834 /** 
835  * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
836  * @cpu: CPU number
837  *
838  * This is the last known freq, without actually getting it from the driver.
839  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
840  */
841 unsigned int cpufreq_quick_get(unsigned int cpu)
842 {
843         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
844         unsigned int ret = 0;
845
846         if (policy) {
847                 mutex_lock(&policy->lock);
848                 ret = policy->cur;
849                 mutex_unlock(&policy->lock);
850                 cpufreq_cpu_put(policy);
851         }
852
853         return (ret);
854 }
855 EXPORT_SYMBOL(cpufreq_quick_get);
856
857
858 /** 
859  * cpufreq_get - get the current CPU frequency (in kHz)
860  * @cpu: CPU number
861  *
862  * Get the CPU current (static) CPU frequency
863  */
864 unsigned int cpufreq_get(unsigned int cpu)
865 {
866         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
867         unsigned int ret = 0;
868
869         if (!policy)
870                 return 0;
871
872         if (!cpufreq_driver->get)
873                 goto out;
874
875         mutex_lock(&policy->lock);
876
877         ret = cpufreq_driver->get(cpu);
878
879         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
880                 /* verify no discrepancy between actual and saved value exists */
881                 if (unlikely(ret != policy->cur)) {
882                         cpufreq_out_of_sync(cpu, policy->cur, ret);
883                         schedule_work(&policy->update);
884                 }
885         }
886
887         mutex_unlock(&policy->lock);
888
889 out:
890         cpufreq_cpu_put(policy);
891
892         return (ret);
893 }
894 EXPORT_SYMBOL(cpufreq_get);
895
896
897 /**
898  *      cpufreq_suspend - let the low level driver prepare for suspend
899  */
900
901 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
902 {
903         int cpu = sysdev->id;
904         unsigned int ret = 0;
905         unsigned int cur_freq = 0;
906         struct cpufreq_policy *cpu_policy;
907
908         dprintk("resuming cpu %u\n", cpu);
909
910         if (!cpu_online(cpu))
911                 return 0;
912
913         /* we may be lax here as interrupts are off. Nonetheless
914          * we need to grab the correct cpu policy, as to check
915          * whether we really run on this CPU.
916          */
917
918         cpu_policy = cpufreq_cpu_get(cpu);
919         if (!cpu_policy)
920                 return -EINVAL;
921
922         /* only handle each CPU group once */
923         if (unlikely(cpu_policy->cpu != cpu)) {
924                 cpufreq_cpu_put(cpu_policy);
925                 return 0;
926         }
927
928         if (cpufreq_driver->suspend) {
929                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
930                 if (ret) {
931                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
932                                         "step on CPU %u\n", cpu_policy->cpu);
933                         cpufreq_cpu_put(cpu_policy);
934                         return ret;
935                 }
936         }
937
938
939         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
940                 goto out;
941
942         if (cpufreq_driver->get)
943                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
944
945         if (!cur_freq || !cpu_policy->cur) {
946                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
947                        "frequency is what timing core thinks it is.\n");
948                 goto out;
949         }
950
951         if (unlikely(cur_freq != cpu_policy->cur)) {
952                 struct cpufreq_freqs freqs;
953
954                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
955                         dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
956                                "cpufreq assumed %u kHz.\n",
957                                cur_freq, cpu_policy->cur);
958
959                 freqs.cpu = cpu;
960                 freqs.old = cpu_policy->cur;
961                 freqs.new = cur_freq;
962
963                 notifier_call_chain(&cpufreq_transition_notifier_list,
964                                     CPUFREQ_SUSPENDCHANGE, &freqs);
965                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
966
967                 cpu_policy->cur = cur_freq;
968         }
969
970 out:
971         cpufreq_cpu_put(cpu_policy);
972         return 0;
973 }
974
975 /**
976  *      cpufreq_resume -  restore proper CPU frequency handling after resume
977  *
978  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
979  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
980  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
981  *          restored.
982  */
983 static int cpufreq_resume(struct sys_device * sysdev)
984 {
985         int cpu = sysdev->id;
986         unsigned int ret = 0;
987         struct cpufreq_policy *cpu_policy;
988
989         dprintk("resuming cpu %u\n", cpu);
990
991         if (!cpu_online(cpu))
992                 return 0;
993
994         /* we may be lax here as interrupts are off. Nonetheless
995          * we need to grab the correct cpu policy, as to check
996          * whether we really run on this CPU.
997          */
998
999         cpu_policy = cpufreq_cpu_get(cpu);
1000         if (!cpu_policy)
1001                 return -EINVAL;
1002
1003         /* only handle each CPU group once */
1004         if (unlikely(cpu_policy->cpu != cpu)) {
1005                 cpufreq_cpu_put(cpu_policy);
1006                 return 0;
1007         }
1008
1009         if (cpufreq_driver->resume) {
1010                 ret = cpufreq_driver->resume(cpu_policy);
1011                 if (ret) {
1012                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1013                                         "step on CPU %u\n", cpu_policy->cpu);
1014                         cpufreq_cpu_put(cpu_policy);
1015                         return ret;
1016                 }
1017         }
1018
1019         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1020                 unsigned int cur_freq = 0;
1021
1022                 if (cpufreq_driver->get)
1023                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1024
1025                 if (!cur_freq || !cpu_policy->cur) {
1026                         printk(KERN_ERR "cpufreq: resume failed to assert "
1027                                         "current frequency is what timing core "
1028                                         "thinks it is.\n");
1029                         goto out;
1030                 }
1031
1032                 if (unlikely(cur_freq != cpu_policy->cur)) {
1033                         struct cpufreq_freqs freqs;
1034
1035                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1036                                 dprintk(KERN_WARNING "Warning: CPU frequency"
1037                                        "is %u, cpufreq assumed %u kHz.\n",
1038                                        cur_freq, cpu_policy->cur);
1039
1040                         freqs.cpu = cpu;
1041                         freqs.old = cpu_policy->cur;
1042                         freqs.new = cur_freq;
1043
1044                         notifier_call_chain(&cpufreq_transition_notifier_list,
1045                                         CPUFREQ_RESUMECHANGE, &freqs);
1046                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1047
1048                         cpu_policy->cur = cur_freq;
1049                 }
1050         }
1051
1052 out:
1053         schedule_work(&cpu_policy->update);
1054         cpufreq_cpu_put(cpu_policy);
1055         return ret;
1056 }
1057
1058 static struct sysdev_driver cpufreq_sysdev_driver = {
1059         .add            = cpufreq_add_dev,
1060         .remove         = cpufreq_remove_dev,
1061         .suspend        = cpufreq_suspend,
1062         .resume         = cpufreq_resume,
1063 };
1064
1065
1066 /*********************************************************************
1067  *                     NOTIFIER LISTS INTERFACE                      *
1068  *********************************************************************/
1069
1070 /**
1071  *      cpufreq_register_notifier - register a driver with cpufreq
1072  *      @nb: notifier function to register
1073  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1074  *
1075  *      Add a driver to one of two lists: either a list of drivers that 
1076  *      are notified about clock rate changes (once before and once after
1077  *      the transition), or a list of drivers that are notified about
1078  *      changes in cpufreq policy.
1079  *
1080  *      This function may sleep, and has the same return conditions as
1081  *      notifier_chain_register.
1082  */
1083 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1084 {
1085         int ret;
1086
1087         down_write(&cpufreq_notifier_rwsem);
1088         switch (list) {
1089         case CPUFREQ_TRANSITION_NOTIFIER:
1090                 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
1091                 break;
1092         case CPUFREQ_POLICY_NOTIFIER:
1093                 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
1094                 break;
1095         default:
1096                 ret = -EINVAL;
1097         }
1098         up_write(&cpufreq_notifier_rwsem);
1099
1100         return ret;
1101 }
1102 EXPORT_SYMBOL(cpufreq_register_notifier);
1103
1104
1105 /**
1106  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1107  *      @nb: notifier block to be unregistered
1108  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1109  *
1110  *      Remove a driver from the CPU frequency notifier list.
1111  *
1112  *      This function may sleep, and has the same return conditions as
1113  *      notifier_chain_unregister.
1114  */
1115 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1116 {
1117         int ret;
1118
1119         down_write(&cpufreq_notifier_rwsem);
1120         switch (list) {
1121         case CPUFREQ_TRANSITION_NOTIFIER:
1122                 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1123                 break;
1124         case CPUFREQ_POLICY_NOTIFIER:
1125                 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1126                 break;
1127         default:
1128                 ret = -EINVAL;
1129         }
1130         up_write(&cpufreq_notifier_rwsem);
1131
1132         return ret;
1133 }
1134 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1135
1136
1137 /*********************************************************************
1138  *                              GOVERNORS                            *
1139  *********************************************************************/
1140
1141
1142 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1143                             unsigned int target_freq,
1144                             unsigned int relation)
1145 {
1146         int retval = -EINVAL;
1147
1148         lock_cpu_hotplug();
1149         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1150                 target_freq, relation);
1151         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1152                 retval = cpufreq_driver->target(policy, target_freq, relation);
1153
1154         unlock_cpu_hotplug();
1155
1156         return retval;
1157 }
1158 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1159
1160 int cpufreq_driver_target(struct cpufreq_policy *policy,
1161                           unsigned int target_freq,
1162                           unsigned int relation)
1163 {
1164         int ret;
1165
1166         policy = cpufreq_cpu_get(policy->cpu);
1167         if (!policy)
1168                 return -EINVAL;
1169
1170         mutex_lock(&policy->lock);
1171
1172         ret = __cpufreq_driver_target(policy, target_freq, relation);
1173
1174         mutex_unlock(&policy->lock);
1175
1176         cpufreq_cpu_put(policy);
1177         return ret;
1178 }
1179 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1180
1181
1182 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1183 {
1184         int ret;
1185
1186         if (!try_module_get(policy->governor->owner))
1187                 return -EINVAL;
1188
1189         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1190         ret = policy->governor->governor(policy, event);
1191
1192         /* we keep one module reference alive for each CPU governed by this CPU */
1193         if ((event != CPUFREQ_GOV_START) || ret)
1194                 module_put(policy->governor->owner);
1195         if ((event == CPUFREQ_GOV_STOP) && !ret)
1196                 module_put(policy->governor->owner);
1197
1198         return ret;
1199 }
1200
1201
1202 int cpufreq_governor(unsigned int cpu, unsigned int event)
1203 {
1204         int ret = 0;
1205         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1206
1207         if (!policy)
1208                 return -EINVAL;
1209
1210         mutex_lock(&policy->lock);
1211         ret = __cpufreq_governor(policy, event);
1212         mutex_unlock(&policy->lock);
1213
1214         cpufreq_cpu_put(policy);
1215         return ret;
1216 }
1217 EXPORT_SYMBOL_GPL(cpufreq_governor);
1218
1219
1220 int cpufreq_register_governor(struct cpufreq_governor *governor)
1221 {
1222         struct cpufreq_governor *t;
1223
1224         if (!governor)
1225                 return -EINVAL;
1226
1227         mutex_lock(&cpufreq_governor_mutex);
1228         
1229         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1230                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1231                         mutex_unlock(&cpufreq_governor_mutex);
1232                         return -EBUSY;
1233                 }
1234         }
1235         list_add(&governor->governor_list, &cpufreq_governor_list);
1236
1237         mutex_unlock(&cpufreq_governor_mutex);
1238         return 0;
1239 }
1240 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1241
1242
1243 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1244 {
1245         if (!governor)
1246                 return;
1247
1248         mutex_lock(&cpufreq_governor_mutex);
1249         list_del(&governor->governor_list);
1250         mutex_unlock(&cpufreq_governor_mutex);
1251         return;
1252 }
1253 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1254
1255
1256
1257 /*********************************************************************
1258  *                          POLICY INTERFACE                         *
1259  *********************************************************************/
1260
1261 /**
1262  * cpufreq_get_policy - get the current cpufreq_policy
1263  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1264  *
1265  * Reads the current cpufreq policy.
1266  */
1267 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1268 {
1269         struct cpufreq_policy *cpu_policy;
1270         if (!policy)
1271                 return -EINVAL;
1272
1273         cpu_policy = cpufreq_cpu_get(cpu);
1274         if (!cpu_policy)
1275                 return -EINVAL;
1276
1277         mutex_lock(&cpu_policy->lock);
1278         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1279         mutex_unlock(&cpu_policy->lock);
1280
1281         cpufreq_cpu_put(cpu_policy);
1282         return 0;
1283 }
1284 EXPORT_SYMBOL(cpufreq_get_policy);
1285
1286
1287 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1288 {
1289         int ret = 0;
1290
1291         cpufreq_debug_disable_ratelimit();
1292         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1293                 policy->min, policy->max);
1294
1295         memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo));
1296
1297         /* verify the cpu speed can be set within this limit */
1298         ret = cpufreq_driver->verify(policy);
1299         if (ret)
1300                 goto error_out;
1301
1302         down_read(&cpufreq_notifier_rwsem);
1303
1304         /* adjust if necessary - all reasons */
1305         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1306                             policy);
1307
1308         /* adjust if necessary - hardware incompatibility*/
1309         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1310                             policy);
1311
1312         /* verify the cpu speed can be set within this limit,
1313            which might be different to the first one */
1314         ret = cpufreq_driver->verify(policy);
1315         if (ret) {
1316                 up_read(&cpufreq_notifier_rwsem);
1317                 goto error_out;
1318         }
1319
1320         /* notification of the new policy */
1321         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1322                             policy);
1323
1324         up_read(&cpufreq_notifier_rwsem);
1325
1326         data->min = policy->min;
1327         data->max = policy->max;
1328
1329         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1330
1331         if (cpufreq_driver->setpolicy) {
1332                 data->policy = policy->policy;
1333                 dprintk("setting range\n");
1334                 ret = cpufreq_driver->setpolicy(policy);
1335         } else {
1336                 if (policy->governor != data->governor) {
1337                         /* save old, working values */
1338                         struct cpufreq_governor *old_gov = data->governor;
1339
1340                         dprintk("governor switch\n");
1341
1342                         /* end old governor */
1343                         if (data->governor)
1344                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1345
1346                         /* start new governor */
1347                         data->governor = policy->governor;
1348                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1349                                 /* new governor failed, so re-start old one */
1350                                 dprintk("starting governor %s failed\n", data->governor->name);
1351                                 if (old_gov) {
1352                                         data->governor = old_gov;
1353                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1354                                 }
1355                                 ret = -EINVAL;
1356                                 goto error_out;
1357                         }
1358                         /* might be a policy change, too, so fall through */
1359                 }
1360                 dprintk("governor: change or update limits\n");
1361                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1362         }
1363
1364 error_out:
1365         cpufreq_debug_enable_ratelimit();
1366         return ret;
1367 }
1368
1369 /**
1370  *      cpufreq_set_policy - set a new CPUFreq policy
1371  *      @policy: policy to be set.
1372  *
1373  *      Sets a new CPU frequency and voltage scaling policy.
1374  */
1375 int cpufreq_set_policy(struct cpufreq_policy *policy)
1376 {
1377         int ret = 0;
1378         struct cpufreq_policy *data;
1379
1380         if (!policy)
1381                 return -EINVAL;
1382
1383         data = cpufreq_cpu_get(policy->cpu);
1384         if (!data)
1385                 return -EINVAL;
1386
1387         /* lock this CPU */
1388         mutex_lock(&data->lock);
1389
1390         ret = __cpufreq_set_policy(data, policy);
1391         data->user_policy.min = data->min;
1392         data->user_policy.max = data->max;
1393         data->user_policy.policy = data->policy;
1394         data->user_policy.governor = data->governor;
1395
1396         mutex_unlock(&data->lock);
1397         cpufreq_cpu_put(data);
1398
1399         return ret;
1400 }
1401 EXPORT_SYMBOL(cpufreq_set_policy);
1402
1403
1404 /**
1405  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1406  *      @cpu: CPU which shall be re-evaluated
1407  *
1408  *      Usefull for policy notifiers which have different necessities
1409  *      at different times.
1410  */
1411 int cpufreq_update_policy(unsigned int cpu)
1412 {
1413         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1414         struct cpufreq_policy policy;
1415         int ret = 0;
1416
1417         if (!data)
1418                 return -ENODEV;
1419
1420         mutex_lock(&data->lock);
1421
1422         dprintk("updating policy for CPU %u\n", cpu);
1423         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1424         policy.min = data->user_policy.min;
1425         policy.max = data->user_policy.max;
1426         policy.policy = data->user_policy.policy;
1427         policy.governor = data->user_policy.governor;
1428
1429         /* BIOS might change freq behind our back
1430           -> ask driver for current freq and notify governors about a change */
1431         if (cpufreq_driver->get) {
1432                 policy.cur = cpufreq_driver->get(cpu);
1433                 if (!data->cur) {
1434                         dprintk("Driver did not initialize current freq");
1435                         data->cur = policy.cur;
1436                 } else {
1437                         if (data->cur != policy.cur)
1438                                 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1439                 }
1440         }
1441
1442         ret = __cpufreq_set_policy(data, &policy);
1443
1444         mutex_unlock(&data->lock);
1445
1446         cpufreq_cpu_put(data);
1447         return ret;
1448 }
1449 EXPORT_SYMBOL(cpufreq_update_policy);
1450
1451 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1452                                         unsigned long action, void *hcpu)
1453 {
1454         unsigned int cpu = (unsigned long)hcpu;
1455         struct cpufreq_policy *policy;
1456         struct sys_device *sys_dev;
1457
1458         sys_dev = get_cpu_sysdev(cpu);
1459
1460         if (sys_dev) {
1461                 switch (action) {
1462                 case CPU_ONLINE:
1463                         cpufreq_add_dev(sys_dev);
1464                         break;
1465                 case CPU_DOWN_PREPARE:
1466                         /*
1467                          * We attempt to put this cpu in lowest frequency
1468                          * possible before going down. This will permit
1469                          * hardware-managed P-State to switch other related
1470                          * threads to min or higher speeds if possible.
1471                          */
1472                         policy = cpufreq_cpu_data[cpu];
1473                         if (policy) {
1474                                 cpufreq_driver_target(policy, policy->min,
1475                                                 CPUFREQ_RELATION_H);
1476                         }
1477                         break;
1478                 case CPU_DEAD:
1479                         cpufreq_remove_dev(sys_dev);
1480                         break;
1481                 }
1482         }
1483         return NOTIFY_OK;
1484 }
1485
1486 static struct notifier_block cpufreq_cpu_notifier =
1487 {
1488     .notifier_call = cpufreq_cpu_callback,
1489 };
1490
1491 /*********************************************************************
1492  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1493  *********************************************************************/
1494
1495 /**
1496  * cpufreq_register_driver - register a CPU Frequency driver
1497  * @driver_data: A struct cpufreq_driver containing the values#
1498  * submitted by the CPU Frequency driver.
1499  *
1500  *   Registers a CPU Frequency driver to this core code. This code 
1501  * returns zero on success, -EBUSY when another driver got here first
1502  * (and isn't unregistered in the meantime). 
1503  *
1504  */
1505 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1506 {
1507         unsigned long flags;
1508         int ret;
1509
1510         if (!driver_data || !driver_data->verify || !driver_data->init ||
1511             ((!driver_data->setpolicy) && (!driver_data->target)))
1512                 return -EINVAL;
1513
1514         dprintk("trying to register driver %s\n", driver_data->name);
1515
1516         if (driver_data->setpolicy)
1517                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1518
1519         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1520         if (cpufreq_driver) {
1521                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1522                 return -EBUSY;
1523         }
1524         cpufreq_driver = driver_data;
1525         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1526
1527         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1528
1529         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1530                 int i;
1531                 ret = -ENODEV;
1532
1533                 /* check for at least one working CPU */
1534                 for (i=0; i<NR_CPUS; i++)
1535                         if (cpufreq_cpu_data[i])
1536                                 ret = 0;
1537
1538                 /* if all ->init() calls failed, unregister */
1539                 if (ret) {
1540                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1541                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1542
1543                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1544                         cpufreq_driver = NULL;
1545                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1546                 }
1547         }
1548
1549         if (!ret) {
1550                 register_cpu_notifier(&cpufreq_cpu_notifier);
1551                 dprintk("driver %s up and running\n", driver_data->name);
1552                 cpufreq_debug_enable_ratelimit();
1553         }
1554
1555         return (ret);
1556 }
1557 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1558
1559
1560 /**
1561  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1562  *
1563  *    Unregister the current CPUFreq driver. Only call this if you have 
1564  * the right to do so, i.e. if you have succeeded in initialising before!
1565  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1566  * currently not initialised.
1567  */
1568 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1569 {
1570         unsigned long flags;
1571
1572         cpufreq_debug_disable_ratelimit();
1573
1574         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1575                 cpufreq_debug_enable_ratelimit();
1576                 return -EINVAL;
1577         }
1578
1579         dprintk("unregistering driver %s\n", driver->name);
1580
1581         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1582         unregister_cpu_notifier(&cpufreq_cpu_notifier);
1583
1584         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1585         cpufreq_driver = NULL;
1586         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1587
1588         return 0;
1589 }
1590 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);