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