[PATCH] sysfs: (rest) if show/store is missing return -EIO
[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  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  */
12
13 #include <linux/config.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/notifier.h>
18 #include <linux/cpufreq.h>
19 #include <linux/delay.h>
20 #include <linux/interrupt.h>
21 #include <linux/spinlock.h>
22 #include <linux/device.h>
23 #include <linux/slab.h>
24 #include <linux/cpu.h>
25 #include <linux/completion.h>
26
27 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
28
29 /**
30  * The "cpufreq driver" - the arch- or hardware-dependend low
31  * level driver of CPUFreq support, and its spinlock. This lock
32  * also protects the cpufreq_cpu_data array.
33  */
34 static struct cpufreq_driver    *cpufreq_driver;
35 static struct cpufreq_policy    *cpufreq_cpu_data[NR_CPUS];
36 static DEFINE_SPINLOCK(cpufreq_driver_lock);
37
38
39 /* we keep a copy of all ->add'ed CPU's struct sys_device here;
40  * as it is only accessed in ->add and ->remove, no lock or reference
41  * count is necessary.
42  */
43 static struct sys_device        *cpu_sys_devices[NR_CPUS];
44
45
46 /* internal prototypes */
47 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
48 static void handle_update(void *data);
49 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci);
50
51 /**
52  * Two notifier lists: the "policy" list is involved in the 
53  * validation process for a new CPU frequency policy; the 
54  * "transition" list for kernel code that needs to handle
55  * changes to devices when the CPU clock speed changes.
56  * The mutex locks both lists.
57  */
58 static struct notifier_block    *cpufreq_policy_notifier_list;
59 static struct notifier_block    *cpufreq_transition_notifier_list;
60 static DECLARE_RWSEM            (cpufreq_notifier_rwsem);
61
62
63 static LIST_HEAD(cpufreq_governor_list);
64 static DECLARE_MUTEX            (cpufreq_governor_sem);
65
66 struct cpufreq_policy * cpufreq_cpu_get(unsigned int cpu)
67 {
68         struct cpufreq_policy *data;
69         unsigned long flags;
70
71         if (cpu >= NR_CPUS)
72                 goto err_out;
73
74         /* get the cpufreq driver */
75         spin_lock_irqsave(&cpufreq_driver_lock, flags);
76
77         if (!cpufreq_driver)
78                 goto err_out_unlock;
79
80         if (!try_module_get(cpufreq_driver->owner))
81                 goto err_out_unlock;
82
83
84         /* get the CPU */
85         data = cpufreq_cpu_data[cpu];
86
87         if (!data)
88                 goto err_out_put_module;
89
90         if (!kobject_get(&data->kobj))
91                 goto err_out_put_module;
92
93
94         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
95
96         return data;
97
98  err_out_put_module:
99         module_put(cpufreq_driver->owner);
100  err_out_unlock:
101         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
102  err_out:
103         return NULL;
104 }
105 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
106
107 void cpufreq_cpu_put(struct cpufreq_policy *data)
108 {
109         kobject_put(&data->kobj);
110         module_put(cpufreq_driver->owner);
111 }
112 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
113
114
115 /*********************************************************************
116  *                     UNIFIED DEBUG HELPERS                         *
117  *********************************************************************/
118 #ifdef CONFIG_CPU_FREQ_DEBUG
119
120 /* what part(s) of the CPUfreq subsystem are debugged? */
121 static unsigned int debug;
122
123 /* is the debug output ratelimit'ed using printk_ratelimit? User can
124  * set or modify this value.
125  */
126 static unsigned int debug_ratelimit = 1;
127
128 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
129  * loading of a cpufreq driver, temporarily disabled when a new policy
130  * is set, and disabled upon cpufreq driver removal
131  */
132 static unsigned int disable_ratelimit = 1;
133 static DEFINE_SPINLOCK(disable_ratelimit_lock);
134
135 static inline void cpufreq_debug_enable_ratelimit(void)
136 {
137         unsigned long flags;
138
139         spin_lock_irqsave(&disable_ratelimit_lock, flags);
140         if (disable_ratelimit)
141                 disable_ratelimit--;
142         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
143 }
144
145 static inline void cpufreq_debug_disable_ratelimit(void)
146 {
147         unsigned long flags;
148
149         spin_lock_irqsave(&disable_ratelimit_lock, flags);
150         disable_ratelimit++;
151         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
152 }
153
154 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
155 {
156         char s[256];
157         va_list args;
158         unsigned int len;
159         unsigned long flags;
160         
161         WARN_ON(!prefix);
162         if (type & debug) {
163                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
164                 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
165                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
166                         return;
167                 }
168                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
169
170                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
171
172                 va_start(args, fmt);
173                 len += vsnprintf(&s[len], (256 - len), fmt, args);
174                 va_end(args);
175
176                 printk(s);
177
178                 WARN_ON(len < 5);
179         }
180 }
181 EXPORT_SYMBOL(cpufreq_debug_printk);
182
183
184 module_param(debug, uint, 0644);
185 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
186
187 module_param(debug_ratelimit, uint, 0644);
188 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
189
190 #else /* !CONFIG_CPU_FREQ_DEBUG */
191
192 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
193 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
194
195 #endif /* CONFIG_CPU_FREQ_DEBUG */
196
197
198 /*********************************************************************
199  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
200  *********************************************************************/
201
202 /**
203  * adjust_jiffies - adjust the system "loops_per_jiffy"
204  *
205  * This function alters the system "loops_per_jiffy" for the clock
206  * speed change. Note that loops_per_jiffy cannot be updated on SMP
207  * systems as each CPU might be scaled differently. So, use the arch 
208  * per-CPU loops_per_jiffy value wherever possible.
209  */
210 #ifndef CONFIG_SMP
211 static unsigned long l_p_j_ref;
212 static unsigned int  l_p_j_ref_freq;
213
214 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
215 {
216         if (ci->flags & CPUFREQ_CONST_LOOPS)
217                 return;
218
219         if (!l_p_j_ref_freq) {
220                 l_p_j_ref = loops_per_jiffy;
221                 l_p_j_ref_freq = ci->old;
222                 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
223         }
224         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
225             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
226             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
227                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
228                 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
229         }
230 }
231 #else
232 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
233 #endif
234
235
236 /**
237  * cpufreq_notify_transition - call notifier chain and adjust_jiffies on frequency transition
238  *
239  * This function calls the transition notifiers and the "adjust_jiffies" function. It is called
240  * twice on all CPU frequency changes that have external effects. 
241  */
242 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
243 {
244         BUG_ON(irqs_disabled());
245
246         freqs->flags = cpufreq_driver->flags;
247         dprintk("notification %u of frequency transition to %u kHz\n", state, freqs->new);
248
249         down_read(&cpufreq_notifier_rwsem);
250         switch (state) {
251         case CPUFREQ_PRECHANGE:
252                 /* detect if the driver reported a value as "old frequency" which
253                  * is not equal to what the cpufreq core thinks is "old frequency".
254                  */
255                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
256                         if ((likely(cpufreq_cpu_data[freqs->cpu])) &&
257                             (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)) &&
258                             (likely(cpufreq_cpu_data[freqs->cpu]->cur)) &&
259                             (unlikely(freqs->old != cpufreq_cpu_data[freqs->cpu]->cur)))
260                         {
261                                 dprintk(KERN_WARNING "Warning: CPU frequency is %u, "
262                                        "cpufreq assumed %u kHz.\n", freqs->old, cpufreq_cpu_data[freqs->cpu]->cur);
263                                 freqs->old = cpufreq_cpu_data[freqs->cpu]->cur;
264                         }
265                 }
266                 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs);
267                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
268                 break;
269         case CPUFREQ_POSTCHANGE:
270                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
271                 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs);
272                 if ((likely(cpufreq_cpu_data[freqs->cpu])) && 
273                     (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)))
274                         cpufreq_cpu_data[freqs->cpu]->cur = freqs->new;
275                 break;
276         }
277         up_read(&cpufreq_notifier_rwsem);
278 }
279 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
280
281
282
283 /*********************************************************************
284  *                          SYSFS INTERFACE                          *
285  *********************************************************************/
286
287 /**
288  * cpufreq_parse_governor - parse a governor string
289  */
290 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
291                                 struct cpufreq_governor **governor)
292 {
293         if (!cpufreq_driver)
294                 return -EINVAL;
295         if (cpufreq_driver->setpolicy) {
296                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
297                         *policy = CPUFREQ_POLICY_PERFORMANCE;
298                         return 0;
299                 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
300                         *policy = CPUFREQ_POLICY_POWERSAVE;
301                         return 0;
302                 }
303                 return -EINVAL;
304         } else {
305                 struct cpufreq_governor *t;
306                 down(&cpufreq_governor_sem);
307                 if (!cpufreq_driver || !cpufreq_driver->target)
308                         goto out;
309                 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
310                         if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
311                                 *governor = t;
312                                 up(&cpufreq_governor_sem);
313                                 return 0;
314                         }
315                 }
316         out:
317                 up(&cpufreq_governor_sem);
318         }
319         return -EINVAL;
320 }
321 EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
322
323
324 /* drivers/base/cpu.c */
325 extern struct sysdev_class cpu_sysdev_class;
326
327
328 /**
329  * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
330  *
331  * Write out information from cpufreq_driver->policy[cpu]; object must be
332  * "unsigned int".
333  */
334
335 #define show_one(file_name, object)                                     \
336 static ssize_t show_##file_name                                         \
337 (struct cpufreq_policy * policy, char *buf)                             \
338 {                                                                       \
339         return sprintf (buf, "%u\n", policy->object);                   \
340 }
341
342 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
343 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
344 show_one(scaling_min_freq, min);
345 show_one(scaling_max_freq, max);
346 show_one(scaling_cur_freq, cur);
347
348 /**
349  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
350  */
351 #define store_one(file_name, object)                    \
352 static ssize_t store_##file_name                                        \
353 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
354 {                                                                       \
355         unsigned int ret = -EINVAL;                                     \
356         struct cpufreq_policy new_policy;                               \
357                                                                         \
358         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
359         if (ret)                                                        \
360                 return -EINVAL;                                         \
361                                                                         \
362         ret = sscanf (buf, "%u", &new_policy.object);                   \
363         if (ret != 1)                                                   \
364                 return -EINVAL;                                         \
365                                                                         \
366         ret = cpufreq_set_policy(&new_policy);                          \
367                                                                         \
368         return ret ? ret : count;                                       \
369 }
370
371 store_one(scaling_min_freq,min);
372 store_one(scaling_max_freq,max);
373
374 /**
375  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
376  */
377 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
378 {
379         unsigned int cur_freq = cpufreq_get(policy->cpu);
380         if (!cur_freq)
381                 return sprintf(buf, "<unknown>");
382         return sprintf(buf, "%u\n", cur_freq);
383 }
384
385
386 /**
387  * show_scaling_governor - show the current policy for the specified CPU
388  */
389 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
390 {
391         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
392                 return sprintf(buf, "powersave\n");
393         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
394                 return sprintf(buf, "performance\n");
395         else if (policy->governor)
396                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
397         return -EINVAL;
398 }
399
400
401 /**
402  * store_scaling_governor - store policy for the specified CPU
403  */
404 static ssize_t store_scaling_governor (struct cpufreq_policy * policy, 
405                                        const char *buf, size_t count) 
406 {
407         unsigned int ret = -EINVAL;
408         char    str_governor[16];
409         struct cpufreq_policy new_policy;
410
411         ret = cpufreq_get_policy(&new_policy, policy->cpu);
412         if (ret)
413                 return ret;
414
415         ret = sscanf (buf, "%15s", str_governor);
416         if (ret != 1)
417                 return -EINVAL;
418
419         if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
420                 return -EINVAL;
421
422         ret = cpufreq_set_policy(&new_policy);
423
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         unsigned long flags;
575         unsigned int j;
576
577         cpufreq_debug_disable_ratelimit();
578         dprintk("adding CPU %u\n", cpu);
579
580 #ifdef CONFIG_SMP
581         /* check whether a different CPU already registered this
582          * CPU because it is in the same boat. */
583         policy = cpufreq_cpu_get(cpu);
584         if (unlikely(policy)) {
585                 cpu_sys_devices[cpu] = sys_dev;
586                 dprintk("CPU already managed, adding link\n");
587                 sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
588                 cpufreq_debug_enable_ratelimit();
589                 return 0;
590         }
591 #endif
592
593         if (!try_module_get(cpufreq_driver->owner)) {
594                 ret = -EINVAL;
595                 goto module_out;
596         }
597
598         policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
599         if (!policy) {
600                 ret = -ENOMEM;
601                 goto nomem_out;
602         }
603         memset(policy, 0, sizeof(struct cpufreq_policy));
604
605         policy->cpu = cpu;
606         policy->cpus = cpumask_of_cpu(cpu);
607
608         init_MUTEX_LOCKED(&policy->lock);
609         init_completion(&policy->kobj_unregister);
610         INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
611
612         /* call driver. From then on the cpufreq must be able
613          * to accept all calls to ->verify and ->setpolicy for this CPU
614          */
615         ret = cpufreq_driver->init(policy);
616         if (ret) {
617                 dprintk("initialization failed\n");
618                 goto err_out;
619         }
620
621         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
622
623         /* prepare interface data */
624         policy->kobj.parent = &sys_dev->kobj;
625         policy->kobj.ktype = &ktype_cpufreq;
626         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
627
628         ret = kobject_register(&policy->kobj);
629         if (ret)
630                 goto err_out;
631
632         /* set up files for this cpu device */
633         drv_attr = cpufreq_driver->attr;
634         while ((drv_attr) && (*drv_attr)) {
635                 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
636                 drv_attr++;
637         }
638         if (cpufreq_driver->get)
639                 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
640         if (cpufreq_driver->target)
641                 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
642
643         spin_lock_irqsave(&cpufreq_driver_lock, flags);
644         for_each_cpu_mask(j, policy->cpus)
645                 cpufreq_cpu_data[j] = policy;
646         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
647         policy->governor = NULL; /* to assure that the starting sequence is
648                                   * run in cpufreq_set_policy */
649         up(&policy->lock);
650         
651         /* set default policy */
652         
653         ret = cpufreq_set_policy(&new_policy);
654         if (ret) {
655                 dprintk("setting policy failed\n");
656                 goto err_out_unregister;
657         }
658
659         module_put(cpufreq_driver->owner);
660         cpu_sys_devices[cpu] = sys_dev;
661         dprintk("initialization complete\n");
662         cpufreq_debug_enable_ratelimit();
663         
664         return 0;
665
666
667 err_out_unregister:
668         spin_lock_irqsave(&cpufreq_driver_lock, flags);
669         for_each_cpu_mask(j, policy->cpus)
670                 cpufreq_cpu_data[j] = NULL;
671         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
672
673         kobject_unregister(&policy->kobj);
674         wait_for_completion(&policy->kobj_unregister);
675
676 err_out:
677         kfree(policy);
678
679 nomem_out:
680         module_put(cpufreq_driver->owner);
681  module_out:
682         cpufreq_debug_enable_ratelimit();
683         return ret;
684 }
685
686
687 /**
688  * cpufreq_remove_dev - remove a CPU device
689  *
690  * Removes the cpufreq interface for a CPU device.
691  */
692 static int cpufreq_remove_dev (struct sys_device * sys_dev)
693 {
694         unsigned int cpu = sys_dev->id;
695         unsigned long flags;
696         struct cpufreq_policy *data;
697 #ifdef CONFIG_SMP
698         unsigned int j;
699 #endif
700
701         cpufreq_debug_disable_ratelimit();
702         dprintk("unregistering CPU %u\n", cpu);
703
704         spin_lock_irqsave(&cpufreq_driver_lock, flags);
705         data = cpufreq_cpu_data[cpu];
706
707         if (!data) {
708                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
709                 cpu_sys_devices[cpu] = NULL;
710                 cpufreq_debug_enable_ratelimit();
711                 return -EINVAL;
712         }
713         cpufreq_cpu_data[cpu] = NULL;
714
715
716 #ifdef CONFIG_SMP
717         /* if this isn't the CPU which is the parent of the kobj, we
718          * only need to unlink, put and exit 
719          */
720         if (unlikely(cpu != data->cpu)) {
721                 dprintk("removing link\n");
722                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
723                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
724                 cpu_sys_devices[cpu] = NULL;
725                 cpufreq_cpu_put(data);
726                 cpufreq_debug_enable_ratelimit();
727                 return 0;
728         }
729 #endif
730
731         cpu_sys_devices[cpu] = NULL;
732
733         if (!kobject_get(&data->kobj)) {
734                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
735                 cpufreq_debug_enable_ratelimit();
736                 return -EFAULT;
737         }
738
739 #ifdef CONFIG_SMP
740         /* if we have other CPUs still registered, we need to unlink them,
741          * or else wait_for_completion below will lock up. Clean the
742          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
743          * links afterwards.
744          */
745         if (unlikely(cpus_weight(data->cpus) > 1)) {
746                 for_each_cpu_mask(j, data->cpus) {
747                         if (j == cpu)
748                                 continue;
749                         cpufreq_cpu_data[j] = NULL;
750                 }
751         }
752
753         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
754
755         if (unlikely(cpus_weight(data->cpus) > 1)) {
756                 for_each_cpu_mask(j, data->cpus) {
757                         if (j == cpu)
758                                 continue;
759                         dprintk("removing link for cpu %u\n", j);
760                         sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
761                         cpufreq_cpu_put(data);
762                 }
763         }
764 #else
765         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
766 #endif
767
768         down(&data->lock);
769         if (cpufreq_driver->target)
770                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
771         cpufreq_driver->target = NULL;
772         up(&data->lock);
773
774         kobject_unregister(&data->kobj);
775
776         kobject_put(&data->kobj);
777
778         /* we need to make sure that the underlying kobj is actually
779          * not referenced anymore by anybody before we proceed with 
780          * unloading.
781          */
782         dprintk("waiting for dropping of refcount\n");
783         wait_for_completion(&data->kobj_unregister);
784         dprintk("wait complete\n");
785
786         if (cpufreq_driver->exit)
787                 cpufreq_driver->exit(data);
788
789         kfree(data);
790
791         cpufreq_debug_enable_ratelimit();
792
793         return 0;
794 }
795
796
797 static void handle_update(void *data)
798 {
799         unsigned int cpu = (unsigned int)(long)data;
800         dprintk("handle_update for cpu %u called\n", cpu);
801         cpufreq_update_policy(cpu);
802 }
803
804 /**
805  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
806  *      @cpu: cpu number
807  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
808  *      @new_freq: CPU frequency the CPU actually runs at
809  *
810  *      We adjust to current frequency first, and need to clean up later. So either call
811  *      to cpufreq_update_policy() or schedule handle_update()).
812  */
813 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
814 {
815         struct cpufreq_freqs freqs;
816
817         dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
818                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
819
820         freqs.cpu = cpu;
821         freqs.old = old_freq;
822         freqs.new = new_freq;
823         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
824         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
825 }
826
827
828 /** 
829  * cpufreq_get - get the current CPU frequency (in kHz)
830  * @cpu: CPU number
831  *
832  * Get the CPU current (static) CPU frequency
833  */
834 unsigned int cpufreq_get(unsigned int cpu)
835 {
836         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
837         unsigned int ret = 0;
838
839         if (!policy)
840                 return 0;
841
842         if (!cpufreq_driver->get)
843                 goto out;
844
845         down(&policy->lock);
846
847         ret = cpufreq_driver->get(cpu);
848
849         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) 
850         {
851                 /* verify no discrepancy between actual and saved value exists */
852                 if (unlikely(ret != policy->cur)) {
853                         cpufreq_out_of_sync(cpu, policy->cur, ret);
854                         schedule_work(&policy->update);
855                 }
856         }
857
858         up(&policy->lock);
859
860  out:
861         cpufreq_cpu_put(policy);
862
863         return (ret);
864 }
865 EXPORT_SYMBOL(cpufreq_get);
866
867
868 /**
869  *      cpufreq_suspend - let the low level driver prepare for suspend
870  */
871
872 static int cpufreq_suspend(struct sys_device * sysdev, u32 state)
873 {
874         int cpu = sysdev->id;
875         unsigned int ret = 0;
876         unsigned int cur_freq = 0;
877         struct cpufreq_policy *cpu_policy;
878
879         dprintk("resuming cpu %u\n", cpu);
880
881         if (!cpu_online(cpu))
882                 return 0;
883
884         /* we may be lax here as interrupts are off. Nonetheless
885          * we need to grab the correct cpu policy, as to check
886          * whether we really run on this CPU.
887          */
888
889         cpu_policy = cpufreq_cpu_get(cpu);
890         if (!cpu_policy)
891                 return -EINVAL;
892
893         /* only handle each CPU group once */
894         if (unlikely(cpu_policy->cpu != cpu)) {
895                 cpufreq_cpu_put(cpu_policy);
896                 return 0;
897         }
898
899         if (cpufreq_driver->suspend) {
900                 ret = cpufreq_driver->suspend(cpu_policy, state);
901                 if (ret) {
902                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
903                                         "step on CPU %u\n", cpu_policy->cpu);
904                         cpufreq_cpu_put(cpu_policy);
905                         return ret;
906                 }
907         }
908
909
910         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
911                 goto out;
912
913         if (cpufreq_driver->get)
914                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
915
916         if (!cur_freq || !cpu_policy->cur) {
917                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
918                        "frequency is what timing core thinks it is.\n");
919                 goto out;
920         }
921
922         if (unlikely(cur_freq != cpu_policy->cur)) {
923                 struct cpufreq_freqs freqs;
924
925                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
926                         dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
927                                "cpufreq assumed %u kHz.\n",
928                                cur_freq, cpu_policy->cur);
929
930                 freqs.cpu = cpu;
931                 freqs.old = cpu_policy->cur;
932                 freqs.new = cur_freq;
933
934                 notifier_call_chain(&cpufreq_transition_notifier_list,
935                                     CPUFREQ_SUSPENDCHANGE, &freqs);
936                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
937
938                 cpu_policy->cur = cur_freq;
939         }
940
941  out:
942         cpufreq_cpu_put(cpu_policy);
943         return 0;
944 }
945
946 /**
947  *      cpufreq_resume -  restore proper CPU frequency handling after resume
948  *
949  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
950  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
951  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
952  *          restored.
953  */
954 static int cpufreq_resume(struct sys_device * sysdev)
955 {
956         int cpu = sysdev->id;
957         unsigned int ret = 0;
958         struct cpufreq_policy *cpu_policy;
959
960         dprintk("resuming cpu %u\n", cpu);
961
962         if (!cpu_online(cpu))
963                 return 0;
964
965         /* we may be lax here as interrupts are off. Nonetheless
966          * we need to grab the correct cpu policy, as to check
967          * whether we really run on this CPU.
968          */
969
970         cpu_policy = cpufreq_cpu_get(cpu);
971         if (!cpu_policy)
972                 return -EINVAL;
973
974         /* only handle each CPU group once */
975         if (unlikely(cpu_policy->cpu != cpu)) {
976                 cpufreq_cpu_put(cpu_policy);
977                 return 0;
978         }
979
980         if (cpufreq_driver->resume) {
981                 ret = cpufreq_driver->resume(cpu_policy);
982                 if (ret) {
983                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
984                                         "step on CPU %u\n", cpu_policy->cpu);
985                         cpufreq_cpu_put(cpu_policy);
986                         return ret;
987                 }
988         }
989
990         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
991                 unsigned int cur_freq = 0;
992
993                 if (cpufreq_driver->get)
994                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
995
996                 if (!cur_freq || !cpu_policy->cur) {
997                         printk(KERN_ERR "cpufreq: resume failed to assert "
998                                         "current frequency is what timing core "
999                                         "thinks it is.\n");
1000                         goto out;
1001                 }
1002
1003                 if (unlikely(cur_freq != cpu_policy->cur)) {
1004                         struct cpufreq_freqs freqs;
1005
1006                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1007                                 dprintk(KERN_WARNING "Warning: CPU frequency"
1008                                        "is %u, cpufreq assumed %u kHz.\n",
1009                                        cur_freq, cpu_policy->cur);
1010
1011                         freqs.cpu = cpu;
1012                         freqs.old = cpu_policy->cur;
1013                         freqs.new = cur_freq;
1014
1015                         notifier_call_chain(&cpufreq_transition_notifier_list,
1016                                         CPUFREQ_RESUMECHANGE, &freqs);
1017                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1018
1019                         cpu_policy->cur = cur_freq;
1020                 }
1021         }
1022
1023 out:
1024         schedule_work(&cpu_policy->update);
1025         cpufreq_cpu_put(cpu_policy);
1026         return ret;
1027 }
1028
1029 static struct sysdev_driver cpufreq_sysdev_driver = {
1030         .add            = cpufreq_add_dev,
1031         .remove         = cpufreq_remove_dev,
1032         .suspend        = cpufreq_suspend,
1033         .resume         = cpufreq_resume,
1034 };
1035
1036
1037 /*********************************************************************
1038  *                     NOTIFIER LISTS INTERFACE                      *
1039  *********************************************************************/
1040
1041 /**
1042  *      cpufreq_register_notifier - register a driver with cpufreq
1043  *      @nb: notifier function to register
1044  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1045  *
1046  *      Add a driver to one of two lists: either a list of drivers that 
1047  *      are notified about clock rate changes (once before and once after
1048  *      the transition), or a list of drivers that are notified about
1049  *      changes in cpufreq policy.
1050  *
1051  *      This function may sleep, and has the same return conditions as
1052  *      notifier_chain_register.
1053  */
1054 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1055 {
1056         int ret;
1057
1058         down_write(&cpufreq_notifier_rwsem);
1059         switch (list) {
1060         case CPUFREQ_TRANSITION_NOTIFIER:
1061                 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
1062                 break;
1063         case CPUFREQ_POLICY_NOTIFIER:
1064                 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
1065                 break;
1066         default:
1067                 ret = -EINVAL;
1068         }
1069         up_write(&cpufreq_notifier_rwsem);
1070
1071         return ret;
1072 }
1073 EXPORT_SYMBOL(cpufreq_register_notifier);
1074
1075
1076 /**
1077  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1078  *      @nb: notifier block to be unregistered
1079  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1080  *
1081  *      Remove a driver from the CPU frequency notifier list.
1082  *
1083  *      This function may sleep, and has the same return conditions as
1084  *      notifier_chain_unregister.
1085  */
1086 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1087 {
1088         int ret;
1089
1090         down_write(&cpufreq_notifier_rwsem);
1091         switch (list) {
1092         case CPUFREQ_TRANSITION_NOTIFIER:
1093                 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1094                 break;
1095         case CPUFREQ_POLICY_NOTIFIER:
1096                 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1097                 break;
1098         default:
1099                 ret = -EINVAL;
1100         }
1101         up_write(&cpufreq_notifier_rwsem);
1102
1103         return ret;
1104 }
1105 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1106
1107
1108 /*********************************************************************
1109  *                              GOVERNORS                            *
1110  *********************************************************************/
1111
1112
1113 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1114                             unsigned int target_freq,
1115                             unsigned int relation)
1116 {
1117         int retval = -EINVAL;
1118         lock_cpu_hotplug();
1119         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1120                 target_freq, relation);
1121         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1122                 retval = cpufreq_driver->target(policy, target_freq, relation);
1123         unlock_cpu_hotplug();
1124         return retval;
1125 }
1126 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1127
1128
1129 int cpufreq_driver_target(struct cpufreq_policy *policy,
1130                           unsigned int target_freq,
1131                           unsigned int relation)
1132 {
1133         unsigned int ret;
1134
1135         policy = cpufreq_cpu_get(policy->cpu);
1136         if (!policy)
1137                 return -EINVAL;
1138
1139         down(&policy->lock);
1140
1141         ret = __cpufreq_driver_target(policy, target_freq, relation);
1142
1143         up(&policy->lock);
1144
1145         cpufreq_cpu_put(policy);
1146
1147         return ret;
1148 }
1149 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1150
1151
1152 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1153 {
1154         int ret = -EINVAL;
1155
1156         if (!try_module_get(policy->governor->owner))
1157                 return -EINVAL;
1158
1159         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1160         ret = policy->governor->governor(policy, event);
1161
1162         /* we keep one module reference alive for each CPU governed by this CPU */
1163         if ((event != CPUFREQ_GOV_START) || ret)
1164                 module_put(policy->governor->owner);
1165         if ((event == CPUFREQ_GOV_STOP) && !ret)
1166                 module_put(policy->governor->owner);
1167
1168         return ret;
1169 }
1170
1171
1172 int cpufreq_governor(unsigned int cpu, unsigned int event)
1173 {
1174         int ret = 0;
1175         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1176
1177         if (!policy)
1178                 return -EINVAL;
1179
1180         down(&policy->lock);
1181         ret = __cpufreq_governor(policy, event);
1182         up(&policy->lock);
1183
1184         cpufreq_cpu_put(policy);
1185
1186         return ret;
1187 }
1188 EXPORT_SYMBOL_GPL(cpufreq_governor);
1189
1190
1191 int cpufreq_register_governor(struct cpufreq_governor *governor)
1192 {
1193         struct cpufreq_governor *t;
1194
1195         if (!governor)
1196                 return -EINVAL;
1197
1198         down(&cpufreq_governor_sem);
1199         
1200         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1201                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1202                         up(&cpufreq_governor_sem);
1203                         return -EBUSY;
1204                 }
1205         }
1206         list_add(&governor->governor_list, &cpufreq_governor_list);
1207
1208         up(&cpufreq_governor_sem);
1209
1210         return 0;
1211 }
1212 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1213
1214
1215 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1216 {
1217         if (!governor)
1218                 return;
1219
1220         down(&cpufreq_governor_sem);
1221         list_del(&governor->governor_list);
1222         up(&cpufreq_governor_sem);
1223         return;
1224 }
1225 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1226
1227
1228
1229 /*********************************************************************
1230  *                          POLICY INTERFACE                         *
1231  *********************************************************************/
1232
1233 /**
1234  * cpufreq_get_policy - get the current cpufreq_policy
1235  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1236  *
1237  * Reads the current cpufreq policy.
1238  */
1239 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1240 {
1241         struct cpufreq_policy *cpu_policy;
1242         if (!policy)
1243                 return -EINVAL;
1244
1245         cpu_policy = cpufreq_cpu_get(cpu);
1246         if (!cpu_policy)
1247                 return -EINVAL;
1248
1249         down(&cpu_policy->lock);
1250         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1251         up(&cpu_policy->lock);
1252
1253         cpufreq_cpu_put(cpu_policy);
1254
1255         return 0;
1256 }
1257 EXPORT_SYMBOL(cpufreq_get_policy);
1258
1259
1260 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1261 {
1262         int ret = 0;
1263
1264         cpufreq_debug_disable_ratelimit();
1265         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1266                 policy->min, policy->max);
1267
1268         memcpy(&policy->cpuinfo, 
1269                &data->cpuinfo, 
1270                sizeof(struct cpufreq_cpuinfo));
1271
1272         /* verify the cpu speed can be set within this limit */
1273         ret = cpufreq_driver->verify(policy);
1274         if (ret)
1275                 goto error_out;
1276
1277         down_read(&cpufreq_notifier_rwsem);
1278
1279         /* adjust if necessary - all reasons */
1280         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1281                             policy);
1282
1283         /* adjust if necessary - hardware incompatibility*/
1284         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1285                             policy);
1286
1287         /* verify the cpu speed can be set within this limit,
1288            which might be different to the first one */
1289         ret = cpufreq_driver->verify(policy);
1290         if (ret) {
1291                 up_read(&cpufreq_notifier_rwsem);
1292                 goto error_out;
1293         }
1294
1295         /* notification of the new policy */
1296         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1297                             policy);
1298
1299         up_read(&cpufreq_notifier_rwsem);
1300
1301         data->min    = policy->min;
1302         data->max    = policy->max;
1303
1304         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1305
1306         if (cpufreq_driver->setpolicy) {
1307                 data->policy = policy->policy;
1308                 dprintk("setting range\n");
1309                 ret = cpufreq_driver->setpolicy(policy);
1310         } else {
1311                 if (policy->governor != data->governor) {
1312                         /* save old, working values */
1313                         struct cpufreq_governor *old_gov = data->governor;
1314
1315                         dprintk("governor switch\n");
1316
1317                         /* end old governor */
1318                         if (data->governor)
1319                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1320
1321                         /* start new governor */
1322                         data->governor = policy->governor;
1323                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1324                                 /* new governor failed, so re-start old one */
1325                                 dprintk("starting governor %s failed\n", data->governor->name);
1326                                 if (old_gov) {
1327                                         data->governor = old_gov;
1328                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1329                                 }
1330                                 ret = -EINVAL;
1331                                 goto error_out;
1332                         }
1333                         /* might be a policy change, too, so fall through */
1334                 }
1335                 dprintk("governor: change or update limits\n");
1336                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1337         }
1338
1339  error_out:
1340         cpufreq_debug_enable_ratelimit();
1341         return ret;
1342 }
1343
1344 /**
1345  *      cpufreq_set_policy - set a new CPUFreq policy
1346  *      @policy: policy to be set.
1347  *
1348  *      Sets a new CPU frequency and voltage scaling policy.
1349  */
1350 int cpufreq_set_policy(struct cpufreq_policy *policy)
1351 {
1352         int ret = 0;
1353         struct cpufreq_policy *data;
1354
1355         if (!policy)
1356                 return -EINVAL;
1357
1358         data = cpufreq_cpu_get(policy->cpu);
1359         if (!data)
1360                 return -EINVAL;
1361
1362         /* lock this CPU */
1363         down(&data->lock);
1364
1365         ret = __cpufreq_set_policy(data, policy);
1366         data->user_policy.min = data->min;
1367         data->user_policy.max = data->max;
1368         data->user_policy.policy = data->policy;
1369         data->user_policy.governor = data->governor;
1370
1371         up(&data->lock);
1372         cpufreq_cpu_put(data);
1373
1374         return ret;
1375 }
1376 EXPORT_SYMBOL(cpufreq_set_policy);
1377
1378
1379 /**
1380  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1381  *      @cpu: CPU which shall be re-evaluated
1382  *
1383  *      Usefull for policy notifiers which have different necessities
1384  *      at different times.
1385  */
1386 int cpufreq_update_policy(unsigned int cpu)
1387 {
1388         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1389         struct cpufreq_policy policy;
1390         int ret = 0;
1391
1392         if (!data)
1393                 return -ENODEV;
1394
1395         down(&data->lock);
1396
1397         dprintk("updating policy for CPU %u\n", cpu);
1398         memcpy(&policy, 
1399                data,
1400                sizeof(struct cpufreq_policy));
1401         policy.min = data->user_policy.min;
1402         policy.max = data->user_policy.max;
1403         policy.policy = data->user_policy.policy;
1404         policy.governor = data->user_policy.governor;
1405
1406         ret = __cpufreq_set_policy(data, &policy);
1407
1408         up(&data->lock);
1409
1410         cpufreq_cpu_put(data);
1411         return ret;
1412 }
1413 EXPORT_SYMBOL(cpufreq_update_policy);
1414
1415
1416 /*********************************************************************
1417  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1418  *********************************************************************/
1419
1420 /**
1421  * cpufreq_register_driver - register a CPU Frequency driver
1422  * @driver_data: A struct cpufreq_driver containing the values#
1423  * submitted by the CPU Frequency driver.
1424  *
1425  *   Registers a CPU Frequency driver to this core code. This code 
1426  * returns zero on success, -EBUSY when another driver got here first
1427  * (and isn't unregistered in the meantime). 
1428  *
1429  */
1430 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1431 {
1432         unsigned long flags;
1433         int ret;
1434
1435         if (!driver_data || !driver_data->verify || !driver_data->init ||
1436             ((!driver_data->setpolicy) && (!driver_data->target)))
1437                 return -EINVAL;
1438
1439         dprintk("trying to register driver %s\n", driver_data->name);
1440
1441         if (driver_data->setpolicy)
1442                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1443
1444         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1445         if (cpufreq_driver) {
1446                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1447                 return -EBUSY;
1448         }
1449         cpufreq_driver = driver_data;
1450         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1451
1452         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1453
1454         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1455                 int i;
1456                 ret = -ENODEV;
1457
1458                 /* check for at least one working CPU */
1459                 for (i=0; i<NR_CPUS; i++)
1460                         if (cpufreq_cpu_data[i])
1461                                 ret = 0;
1462
1463                 /* if all ->init() calls failed, unregister */
1464                 if (ret) {
1465                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1466                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1467
1468                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1469                         cpufreq_driver = NULL;
1470                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1471                 }
1472         }
1473
1474         if (!ret) {
1475                 dprintk("driver %s up and running\n", driver_data->name);
1476                 cpufreq_debug_enable_ratelimit();
1477         }
1478
1479         return (ret);
1480 }
1481 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1482
1483
1484 /**
1485  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1486  *
1487  *    Unregister the current CPUFreq driver. Only call this if you have 
1488  * the right to do so, i.e. if you have succeeded in initialising before!
1489  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1490  * currently not initialised.
1491  */
1492 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1493 {
1494         unsigned long flags;
1495
1496         cpufreq_debug_disable_ratelimit();
1497
1498         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1499                 cpufreq_debug_enable_ratelimit();
1500                 return -EINVAL;
1501         }
1502
1503         dprintk("unregistering driver %s\n", driver->name);
1504
1505         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1506
1507         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1508         cpufreq_driver = NULL;
1509         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1510
1511         return 0;
1512 }
1513 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);