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   1 /*
   2  *  linux/drivers/cpufreq/cpufreq.c
   3  *
   4  *  Copyright (C) 2001 Russell King
   5  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
   6  *
   7  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
   8  *      Added handling for CPU hotplug
   9  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
  10  *      Fix handling for CPU hotplug -- affected CPUs
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/notifier.h>
  22 #include <linux/cpufreq.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/device.h>
  27 #include <linux/slab.h>
  28 #include <linux/cpu.h>
  29 #include <linux/completion.h>
  30 #include <linux/mutex.h>
  31
  32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
  33
  34 /**
  35  * The "cpufreq driver" - the arch- or hardware-dependend low
  36  * level driver of CPUFreq support, and its spinlock. This lock
  37  * also protects the cpufreq_cpu_data array.
  38  */
  39 static struct cpufreq_driver *cpufreq_driver;
  40 static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
  41 static DEFINE_SPINLOCK(cpufreq_driver_lock);
  42
  43 /* internal prototypes */
  44 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
  45 static void handle_update(void *data);
  46
  47 /**
  48  * Two notifier lists: the "policy" list is involved in the
  49  * validation process for a new CPU frequency policy; the
  50  * "transition" list for kernel code that needs to handle
  51  * changes to devices when the CPU clock speed changes.
  52  * The mutex locks both lists.
  53  */
  54 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
  55 static BLOCKING_NOTIFIER_HEAD(cpufreq_transition_notifier_list);
  56
  57
  58 static LIST_HEAD(cpufreq_governor_list);
  59 static DEFINE_MUTEX (cpufreq_governor_mutex);
  60
  61 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
  62 {
  63         struct cpufreq_policy *data;
  64         unsigned long flags;
  65
  66         if (cpu >= NR_CPUS)
  67                 goto err_out;
  68
  69         /* get the cpufreq driver */
  70         spin_lock_irqsave(&cpufreq_driver_lock, flags);
  71
  72         if (!cpufreq_driver)
  73                 goto err_out_unlock;
  74
  75         if (!try_module_get(cpufreq_driver->owner))
  76                 goto err_out_unlock;
  77
  78
  79         /* get the CPU */
  80         data = cpufreq_cpu_data[cpu];
  81
  82         if (!data)
  83                 goto err_out_put_module;
  84
  85         if (!kobject_get(&data->kobj))
  86                 goto err_out_put_module;
  87
  88         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
  89         return data;
  90
  91 err_out_put_module:
  92         module_put(cpufreq_driver->owner);
  93 err_out_unlock:
  94         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
  95 err_out:
  96         return NULL;
  97 }
  98 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
  99
 100
 101 void cpufreq_cpu_put(struct cpufreq_policy *data)
 102 {
 103         kobject_put(&data->kobj);
 104         module_put(cpufreq_driver->owner);
 105 }
 106 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 107
 108
 109 /*********************************************************************
 110  *                     UNIFIED DEBUG HELPERS                         *
 111  *********************************************************************/
 112 #ifdef CONFIG_CPU_FREQ_DEBUG
 113
 114 /* what part(s) of the CPUfreq subsystem are debugged? */
 115 static unsigned int debug;
 116
 117 /* is the debug output ratelimit'ed using printk_ratelimit? User can
 118  * set or modify this value.
 119  */
 120 static unsigned int debug_ratelimit = 1;
 121
 122 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
 123  * loading of a cpufreq driver, temporarily disabled when a new policy
 124  * is set, and disabled upon cpufreq driver removal
 125  */
 126 static unsigned int disable_ratelimit = 1;
 127 static DEFINE_SPINLOCK(disable_ratelimit_lock);
 128
 129 static void cpufreq_debug_enable_ratelimit(void)
 130 {
 131         unsigned long flags;
 132
 133         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 134         if (disable_ratelimit)
 135                 disable_ratelimit--;
 136         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 137 }
 138
 139 static void cpufreq_debug_disable_ratelimit(void)
 140 {
 141         unsigned long flags;
 142
 143         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 144         disable_ratelimit++;
 145         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 146 }
 147
 148 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
 149 {
 150         char s[256];
 151         va_list args;
 152         unsigned int len;
 153         unsigned long flags;
 154
 155         WARN_ON(!prefix);
 156         if (type & debug) {
 157                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
 158                 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
 159                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 160                         return;
 161                 }
 162                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 163
 164                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
 165
 166                 va_start(args, fmt);
 167                 len += vsnprintf(&s[len], (256 - len), fmt, args);
 168                 va_end(args);
 169
 170                 printk(s);
 171
 172                 WARN_ON(len < 5);
 173         }
 174 }
 175 EXPORT_SYMBOL(cpufreq_debug_printk);
 176
 177
 178 module_param(debug, uint, 0644);
 179 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
 180
 181 module_param(debug_ratelimit, uint, 0644);
 182 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
 183
 184 #else /* !CONFIG_CPU_FREQ_DEBUG */
 185
 186 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
 187 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
 188
 189 #endif /* CONFIG_CPU_FREQ_DEBUG */
 190
 191
 192 /*********************************************************************
 193  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 194  *********************************************************************/
 195
 196 /**
 197  * adjust_jiffies - adjust the system "loops_per_jiffy"
 198  *
 199  * This function alters the system "loops_per_jiffy" for the clock
 200  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 201  * systems as each CPU might be scaled differently. So, use the arch
 202  * per-CPU loops_per_jiffy value wherever possible.
 203  */
 204 #ifndef CONFIG_SMP
 205 static unsigned long l_p_j_ref;
 206 static unsigned int  l_p_j_ref_freq;
 207
 208 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 209 {
 210         if (ci->flags & CPUFREQ_CONST_LOOPS)
 211                 return;
 212
 213         if (!l_p_j_ref_freq) {
 214                 l_p_j_ref = loops_per_jiffy;
 215                 l_p_j_ref_freq = ci->old;
 216                 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 217         }
 218         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
 219             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
 220             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 221                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
 222                 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
 223         }
 224 }
 225 #else
 226 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
 227 #endif
 228
 229
 230 /**
 231  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
 232  * on frequency transition.
 233  *
 234  * This function calls the transition notifiers and the "adjust_jiffies"
 235  * function. It is called twice on all CPU frequency changes that have
 236  * external effects.
 237  */
 238 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 239 {
 240         struct cpufreq_policy *policy;
 241
 242         BUG_ON(irqs_disabled());
 243
 244         freqs->flags = cpufreq_driver->flags;
 245         dprintk("notification %u of frequency transition to %u kHz\n",
 246                 state, freqs->new);
 247
 248         policy = cpufreq_cpu_data[freqs->cpu];
 249         switch (state) {
 250
 251         case CPUFREQ_PRECHANGE:
 252                 /* detect if the driver reported a value as "old frequency"
 253                  * which is not equal to what the cpufreq core thinks is
 254                  * "old frequency".
 255                  */
 256                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 257                         if ((policy) && (policy->cpu == freqs->cpu) &&
 258                             (policy->cur) && (policy->cur != freqs->old)) {
 259                                 dprintk("Warning: CPU frequency is"
 260                                         " %u, cpufreq assumed %u kHz.\n",
 261                                         freqs->old, policy->cur);
 262                                 freqs->old = policy->cur;
 263                         }
 264                 }
 265                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
 266                                 CPUFREQ_PRECHANGE, freqs);
 267                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 268                 break;
 269
 270         case CPUFREQ_POSTCHANGE:
 271                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 272                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
 273                                 CPUFREQ_POSTCHANGE, freqs);
 274                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
 275                         policy->cur = freqs->new;
 276                 break;
 277         }
 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                 mutex_lock(&cpufreq_governor_mutex);
 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                                 mutex_unlock(&cpufreq_governor_mutex);
 313                                 return 0;
 314                         }
 315                 }
 316 out:
 317                 mutex_unlock(&cpufreq_governor_mutex);
 318         }
 319         return -EINVAL;
 320 }
 321
 322
 323 /* drivers/base/cpu.c */
 324 extern struct sysdev_class cpu_sysdev_class;
 325
 326
 327 /**
 328  * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
 329  *
 330  * Write out information from cpufreq_driver->policy[cpu]; object must be
 331  * "unsigned int".
 332  */
 333
 334 #define show_one(file_name, object)                     \
 335 static ssize_t show_##file_name                         \
 336 (struct cpufreq_policy * policy, char *buf)             \
 337 {                                                       \
 338         return sprintf (buf, "%u\n", policy->object);   \
 339 }
 340
 341 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 342 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 343 show_one(scaling_min_freq, min);
 344 show_one(scaling_max_freq, max);
 345 show_one(scaling_cur_freq, cur);
 346
 347 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy);
 348
 349 /**
 350  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 351  */
 352 #define store_one(file_name, object)                    \
 353 static ssize_t store_##file_name                                        \
 354 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
 355 {                                                                       \
 356         unsigned int ret = -EINVAL;                                     \
 357         struct cpufreq_policy new_policy;                               \
 358                                                                         \
 359         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
 360         if (ret)                                                        \
 361                 return -EINVAL;                                         \
 362                                                                         \
 363         ret = sscanf (buf, "%u", &new_policy.object);                   \
 364         if (ret != 1)                                                   \
 365                 return -EINVAL;                                         \
 366                                                                         \
 367         lock_cpu_hotplug();                                             \
 368         mutex_lock(&policy->lock);                                      \
 369         ret = __cpufreq_set_policy(policy, &new_policy);                \
 370         policy->user_policy.object = policy->object;                    \
 371         mutex_unlock(&policy->lock);                                    \
 372         unlock_cpu_hotplug();                                           \
 373                                                                         \
 374         return ret ? ret : count;                                       \
 375 }
 376
 377 store_one(scaling_min_freq,min);
 378 store_one(scaling_max_freq,max);
 379
 380 /**
 381  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 382  */
 383 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
 384 {
 385         unsigned int cur_freq = cpufreq_get(policy->cpu);
 386         if (!cur_freq)
 387                 return sprintf(buf, "<unknown>");
 388         return sprintf(buf, "%u\n", cur_freq);
 389 }
 390
 391
 392 /**
 393  * show_scaling_governor - show the current policy for the specified CPU
 394  */
 395 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
 396 {
 397         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
 398                 return sprintf(buf, "powersave\n");
 399         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 400                 return sprintf(buf, "performance\n");
 401         else if (policy->governor)
 402                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
 403         return -EINVAL;
 404 }
 405
 406
 407 /**
 408  * store_scaling_governor - store policy for the specified CPU
 409  */
 410 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
 411                                        const char *buf, size_t count)
 412 {
 413         unsigned int ret = -EINVAL;
 414         char    str_governor[16];
 415         struct cpufreq_policy new_policy;
 416
 417         ret = cpufreq_get_policy(&new_policy, policy->cpu);
 418         if (ret)
 419                 return ret;
 420
 421         ret = sscanf (buf, "%15s", str_governor);
 422         if (ret != 1)
 423                 return -EINVAL;
 424
 425         if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
 426                 return -EINVAL;
 427
 428         lock_cpu_hotplug();
 429
 430         /* Do not use cpufreq_set_policy here or the user_policy.max
 431            will be wrongly overridden */
 432         mutex_lock(&policy->lock);
 433         ret = __cpufreq_set_policy(policy, &new_policy);
 434
 435         policy->user_policy.policy = policy->policy;
 436         policy->user_policy.governor = policy->governor;
 437         mutex_unlock(&policy->lock);
 438
 439         unlock_cpu_hotplug();
 440
 441         return ret ? ret : count;
 442 }
 443
 444 /**
 445  * show_scaling_driver - show the cpufreq driver currently loaded
 446  */
 447 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
 448 {
 449         return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
 450 }
 451
 452 /**
 453  * show_scaling_available_governors - show the available CPUfreq governors
 454  */
 455 static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
 456                                 char *buf)
 457 {
 458         ssize_t i = 0;
 459         struct cpufreq_governor *t;
 460
 461         if (!cpufreq_driver->target) {
 462                 i += sprintf(buf, "performance powersave");
 463                 goto out;
 464         }
 465
 466         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 467                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
 468                         goto out;
 469                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
 470         }
 471 out:
 472         i += sprintf(&buf[i], "\n");
 473         return i;
 474 }
 475 /**
 476  * show_affected_cpus - show the CPUs affected by each transition
 477  */
 478 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
 479 {
 480         ssize_t i = 0;
 481         unsigned int cpu;
 482
 483         for_each_cpu_mask(cpu, policy->cpus) {
 484                 if (i)
 485                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 486                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 487                 if (i >= (PAGE_SIZE - 5))
 488                     break;
 489         }
 490         i += sprintf(&buf[i], "\n");
 491         return i;
 492 }
 493
 494
 495 #define define_one_ro(_name) \
 496 static struct freq_attr _name = \
 497 __ATTR(_name, 0444, show_##_name, NULL)
 498
 499 #define define_one_ro0400(_name) \
 500 static struct freq_attr _name = \
 501 __ATTR(_name, 0400, show_##_name, NULL)
 502
 503 #define define_one_rw(_name) \
 504 static struct freq_attr _name = \
 505 __ATTR(_name, 0644, show_##_name, store_##_name)
 506
 507 define_one_ro0400(cpuinfo_cur_freq);
 508 define_one_ro(cpuinfo_min_freq);
 509 define_one_ro(cpuinfo_max_freq);
 510 define_one_ro(scaling_available_governors);
 511 define_one_ro(scaling_driver);
 512 define_one_ro(scaling_cur_freq);
 513 define_one_ro(affected_cpus);
 514 define_one_rw(scaling_min_freq);
 515 define_one_rw(scaling_max_freq);
 516 define_one_rw(scaling_governor);
 517
 518 static struct attribute * default_attrs[] = {
 519         &cpuinfo_min_freq.attr,
 520         &cpuinfo_max_freq.attr,
 521         &scaling_min_freq.attr,
 522         &scaling_max_freq.attr,
 523         &affected_cpus.attr,
 524         &scaling_governor.attr,
 525         &scaling_driver.attr,
 526         &scaling_available_governors.attr,
 527         NULL
 528 };
 529
 530 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
 531 #define to_attr(a) container_of(a,struct freq_attr,attr)
 532
 533 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
 534 {
 535         struct cpufreq_policy * policy = to_policy(kobj);
 536         struct freq_attr * fattr = to_attr(attr);
 537         ssize_t ret;
 538         policy = cpufreq_cpu_get(policy->cpu);
 539         if (!policy)
 540                 return -EINVAL;
 541         ret = fattr->show ? fattr->show(policy,buf) : -EIO;
 542         cpufreq_cpu_put(policy);
 543         return ret;
 544 }
 545
 546 static ssize_t store(struct kobject * kobj, struct attribute * attr,
 547                      const char * buf, size_t count)
 548 {
 549         struct cpufreq_policy * policy = to_policy(kobj);
 550         struct freq_attr * fattr = to_attr(attr);
 551         ssize_t ret;
 552         policy = cpufreq_cpu_get(policy->cpu);
 553         if (!policy)
 554                 return -EINVAL;
 555         ret = fattr->store ? fattr->store(policy,buf,count) : -EIO;
 556         cpufreq_cpu_put(policy);
 557         return ret;
 558 }
 559
 560 static void cpufreq_sysfs_release(struct kobject * kobj)
 561 {
 562         struct cpufreq_policy * policy = to_policy(kobj);
 563         dprintk("last reference is dropped\n");
 564         complete(&policy->kobj_unregister);
 565 }
 566
 567 static struct sysfs_ops sysfs_ops = {
 568         .show   = show,
 569         .store  = store,
 570 };
 571
 572 static struct kobj_type ktype_cpufreq = {
 573         .sysfs_ops      = &sysfs_ops,
 574         .default_attrs  = default_attrs,
 575         .release        = cpufreq_sysfs_release,
 576 };
 577
 578
 579 /**
 580  * cpufreq_add_dev - add a CPU device
 581  *
 582  * Adds the cpufreq interface for a CPU device.
 583  */
 584 static int cpufreq_add_dev (struct sys_device * sys_dev)
 585 {
 586         unsigned int cpu = sys_dev->id;
 587         int ret = 0;
 588         struct cpufreq_policy new_policy;
 589         struct cpufreq_policy *policy;
 590         struct freq_attr **drv_attr;
 591         struct sys_device *cpu_sys_dev;
 592         unsigned long flags;
 593         unsigned int j;
 594 #ifdef CONFIG_SMP
 595         struct cpufreq_policy *managed_policy;
 596 #endif
 597
 598         if (cpu_is_offline(cpu))
 599                 return 0;
 600
 601         cpufreq_debug_disable_ratelimit();
 602         dprintk("adding CPU %u\n", cpu);
 603
 604 #ifdef CONFIG_SMP
 605         /* check whether a different CPU already registered this
 606          * CPU because it is in the same boat. */
 607         policy = cpufreq_cpu_get(cpu);
 608         if (unlikely(policy)) {
 609                 cpufreq_cpu_put(policy);
 610                 cpufreq_debug_enable_ratelimit();
 611                 return 0;
 612         }
 613 #endif
 614
 615         if (!try_module_get(cpufreq_driver->owner)) {
 616                 ret = -EINVAL;
 617                 goto module_out;
 618         }
 619
 620         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
 621         if (!policy) {
 622                 ret = -ENOMEM;
 623                 goto nomem_out;
 624         }
 625
 626         policy->cpu = cpu;
 627         policy->cpus = cpumask_of_cpu(cpu);
 628
 629         mutex_init(&policy->lock);
 630         mutex_lock(&policy->lock);
 631         init_completion(&policy->kobj_unregister);
 632         INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
 633
 634         /* call driver. From then on the cpufreq must be able
 635          * to accept all calls to ->verify and ->setpolicy for this CPU
 636          */
 637         ret = cpufreq_driver->init(policy);
 638         if (ret) {
 639                 dprintk("initialization failed\n");
 640                 mutex_unlock(&policy->lock);
 641                 goto err_out;
 642         }
 643
 644 #ifdef CONFIG_SMP
 645         for_each_cpu_mask(j, policy->cpus) {
 646                 if (cpu == j)
 647                         continue;
 648
 649                 /* check for existing affected CPUs.  They may not be aware
 650                  * of it due to CPU Hotplug.
 651                  */
 652                 managed_policy = cpufreq_cpu_get(j);
 653                 if (unlikely(managed_policy)) {
 654                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 655                         managed_policy->cpus = policy->cpus;
 656                         cpufreq_cpu_data[cpu] = managed_policy;
 657                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 658
 659                         dprintk("CPU already managed, adding link\n");
 660                         sysfs_create_link(&sys_dev->kobj,
 661                                           &managed_policy->kobj, "cpufreq");
 662
 663                         cpufreq_debug_enable_ratelimit();
 664                         mutex_unlock(&policy->lock);
 665                         ret = 0;
 666                         goto err_out_driver_exit; /* call driver->exit() */
 667                 }
 668         }
 669 #endif
 670         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
 671
 672         /* prepare interface data */
 673         policy->kobj.parent = &sys_dev->kobj;
 674         policy->kobj.ktype = &ktype_cpufreq;
 675         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
 676
 677         ret = kobject_register(&policy->kobj);
 678         if (ret) {
 679                 mutex_unlock(&policy->lock);
 680                 goto err_out_driver_exit;
 681         }
 682         /* set up files for this cpu device */
 683         drv_attr = cpufreq_driver->attr;
 684         while ((drv_attr) && (*drv_attr)) {
 685                 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 686                 drv_attr++;
 687         }
 688         if (cpufreq_driver->get)
 689                 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
 690         if (cpufreq_driver->target)
 691                 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 692
 693         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 694         for_each_cpu_mask(j, policy->cpus)
 695                 cpufreq_cpu_data[j] = policy;
 696         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 697
 698         /* symlink affected CPUs */
 699         for_each_cpu_mask(j, policy->cpus) {
 700                 if (j == cpu)
 701                         continue;
 702                 if (!cpu_online(j))
 703                         continue;
 704
 705                 dprintk("CPU %u already managed, adding link\n", j);
 706                 cpufreq_cpu_get(cpu);
 707                 cpu_sys_dev = get_cpu_sysdev(j);
 708                 sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
 709                                   "cpufreq");
 710         }
 711
 712         policy->governor = NULL; /* to assure that the starting sequence is
 713                                   * run in cpufreq_set_policy */
 714         mutex_unlock(&policy->lock);
 715
 716         /* set default policy */
 717         ret = cpufreq_set_policy(&new_policy);
 718         if (ret) {
 719                 dprintk("setting policy failed\n");
 720                 goto err_out_unregister;
 721         }
 722
 723         module_put(cpufreq_driver->owner);
 724         dprintk("initialization complete\n");
 725         cpufreq_debug_enable_ratelimit();
 726
 727         return 0;
 728
 729
 730 err_out_unregister:
 731         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 732         for_each_cpu_mask(j, policy->cpus)
 733                 cpufreq_cpu_data[j] = NULL;
 734         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 735
 736         kobject_unregister(&policy->kobj);
 737         wait_for_completion(&policy->kobj_unregister);
 738
 739 err_out_driver_exit:
 740         if (cpufreq_driver->exit)
 741                 cpufreq_driver->exit(policy);
 742
 743 err_out:
 744         kfree(policy);
 745
 746 nomem_out:
 747         module_put(cpufreq_driver->owner);
 748 module_out:
 749         cpufreq_debug_enable_ratelimit();
 750         return ret;
 751 }
 752
 753
 754 /**
 755  * cpufreq_remove_dev - remove a CPU device
 756  *
 757  * Removes the cpufreq interface for a CPU device.
 758  */
 759 static int cpufreq_remove_dev (struct sys_device * sys_dev)
 760 {
 761         unsigned int cpu = sys_dev->id;
 762         unsigned long flags;
 763         struct cpufreq_policy *data;
 764 #ifdef CONFIG_SMP
 765         struct sys_device *cpu_sys_dev;
 766         unsigned int j;
 767 #endif
 768
 769         cpufreq_debug_disable_ratelimit();
 770         dprintk("unregistering CPU %u\n", cpu);
 771
 772         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 773         data = cpufreq_cpu_data[cpu];
 774
 775         if (!data) {
 776                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 777                 cpufreq_debug_enable_ratelimit();
 778                 return -EINVAL;
 779         }
 780         cpufreq_cpu_data[cpu] = NULL;
 781
 782
 783 #ifdef CONFIG_SMP
 784         /* if this isn't the CPU which is the parent of the kobj, we
 785          * only need to unlink, put and exit
 786          */
 787         if (unlikely(cpu != data->cpu)) {
 788                 dprintk("removing link\n");
 789                 cpu_clear(cpu, data->cpus);
 790                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 791                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
 792                 cpufreq_cpu_put(data);
 793                 cpufreq_debug_enable_ratelimit();
 794                 return 0;
 795         }
 796 #endif
 797
 798
 799         if (!kobject_get(&data->kobj)) {
 800                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 801                 cpufreq_debug_enable_ratelimit();
 802                 return -EFAULT;
 803         }
 804
 805 #ifdef CONFIG_SMP
 806         /* if we have other CPUs still registered, we need to unlink them,
 807          * or else wait_for_completion below will lock up. Clean the
 808          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
 809          * links afterwards.
 810          */
 811         if (unlikely(cpus_weight(data->cpus) > 1)) {
 812                 for_each_cpu_mask(j, data->cpus) {
 813                         if (j == cpu)
 814                                 continue;
 815                         cpufreq_cpu_data[j] = NULL;
 816                 }
 817         }
 818
 819         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 820
 821         if (unlikely(cpus_weight(data->cpus) > 1)) {
 822                 for_each_cpu_mask(j, data->cpus) {
 823                         if (j == cpu)
 824                                 continue;
 825                         dprintk("removing link for cpu %u\n", j);
 826                         cpu_sys_dev = get_cpu_sysdev(j);
 827                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
 828                         cpufreq_cpu_put(data);
 829                 }
 830         }
 831 #else
 832         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 833 #endif
 834
 835         mutex_lock(&data->lock);
 836         if (cpufreq_driver->target)
 837                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
 838         mutex_unlock(&data->lock);
 839
 840         kobject_unregister(&data->kobj);
 841
 842         kobject_put(&data->kobj);
 843
 844         /* we need to make sure that the underlying kobj is actually
 845          * not referenced anymore by anybody before we proceed with
 846          * unloading.
 847          */
 848         dprintk("waiting for dropping of refcount\n");
 849         wait_for_completion(&data->kobj_unregister);
 850         dprintk("wait complete\n");
 851
 852         if (cpufreq_driver->exit)
 853                 cpufreq_driver->exit(data);
 854
 855         kfree(data);
 856
 857         cpufreq_debug_enable_ratelimit();
 858         return 0;
 859 }
 860
 861
 862 static void handle_update(void *data)
 863 {
 864         unsigned int cpu = (unsigned int)(long)data;
 865         dprintk("handle_update for cpu %u called\n", cpu);
 866         cpufreq_update_policy(cpu);
 867 }
 868
 869 /**
 870  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
 871  *      @cpu: cpu number
 872  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
 873  *      @new_freq: CPU frequency the CPU actually runs at
 874  *
 875  *      We adjust to current frequency first, and need to clean up later. So either call
 876  *      to cpufreq_update_policy() or schedule handle_update()).
 877  */
 878 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
 879 {
 880         struct cpufreq_freqs freqs;
 881
 882         dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
 883                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
 884
 885         freqs.cpu = cpu;
 886         freqs.old = old_freq;
 887         freqs.new = new_freq;
 888         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 889         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 890 }
 891
 892
 893 /**
 894  * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
 895  * @cpu: CPU number
 896  *
 897  * This is the last known freq, without actually getting it from the driver.
 898  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
 899  */
 900 unsigned int cpufreq_quick_get(unsigned int cpu)
 901 {
 902         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 903         unsigned int ret = 0;
 904
 905         if (policy) {
 906                 mutex_lock(&policy->lock);
 907                 ret = policy->cur;
 908                 mutex_unlock(&policy->lock);
 909                 cpufreq_cpu_put(policy);
 910         }
 911
 912         return (ret);
 913 }
 914 EXPORT_SYMBOL(cpufreq_quick_get);
 915
 916
 917 /**
 918  * cpufreq_get - get the current CPU frequency (in kHz)
 919  * @cpu: CPU number
 920  *
 921  * Get the CPU current (static) CPU frequency
 922  */
 923 unsigned int cpufreq_get(unsigned int cpu)
 924 {
 925         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 926         unsigned int ret = 0;
 927
 928         if (!policy)
 929                 return 0;
 930
 931         if (!cpufreq_driver->get)
 932                 goto out;
 933
 934         mutex_lock(&policy->lock);
 935
 936         ret = cpufreq_driver->get(cpu);
 937
 938         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 939                 /* verify no discrepancy between actual and saved value exists */
 940                 if (unlikely(ret != policy->cur)) {
 941                         cpufreq_out_of_sync(cpu, policy->cur, ret);
 942                         schedule_work(&policy->update);
 943                 }
 944         }
 945
 946         mutex_unlock(&policy->lock);
 947
 948 out:
 949         cpufreq_cpu_put(policy);
 950
 951         return (ret);
 952 }
 953 EXPORT_SYMBOL(cpufreq_get);
 954
 955
 956 /**
 957  *      cpufreq_suspend - let the low level driver prepare for suspend
 958  */
 959
 960 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
 961 {
 962         int cpu = sysdev->id;
 963         unsigned int ret = 0;
 964         unsigned int cur_freq = 0;
 965         struct cpufreq_policy *cpu_policy;
 966
 967         dprintk("resuming cpu %u\n", cpu);
 968
 969         if (!cpu_online(cpu))
 970                 return 0;
 971
 972         /* we may be lax here as interrupts are off. Nonetheless
 973          * we need to grab the correct cpu policy, as to check
 974          * whether we really run on this CPU.
 975          */
 976
 977         cpu_policy = cpufreq_cpu_get(cpu);
 978         if (!cpu_policy)
 979                 return -EINVAL;
 980
 981         /* only handle each CPU group once */
 982         if (unlikely(cpu_policy->cpu != cpu)) {
 983                 cpufreq_cpu_put(cpu_policy);
 984                 return 0;
 985         }
 986
 987         if (cpufreq_driver->suspend) {
 988                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
 989                 if (ret) {
 990                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
 991                                         "step on CPU %u\n", cpu_policy->cpu);
 992                         cpufreq_cpu_put(cpu_policy);
 993                         return ret;
 994                 }
 995         }
 996
 997
 998         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
 999                 goto out;
1000
1001         if (cpufreq_driver->get)
1002                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1003
1004         if (!cur_freq || !cpu_policy->cur) {
1005                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1006                        "frequency is what timing core thinks it is.\n");
1007                 goto out;
1008         }
1009
1010         if (unlikely(cur_freq != cpu_policy->cur)) {
1011                 struct cpufreq_freqs freqs;
1012
1013                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1014                         dprintk("Warning: CPU frequency is %u, "
1015                                "cpufreq assumed %u kHz.\n",
1016                                cur_freq, cpu_policy->cur);
1017
1018                 freqs.cpu = cpu;
1019                 freqs.old = cpu_policy->cur;
1020                 freqs.new = cur_freq;
1021
1022                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
1023                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1024                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1025
1026                 cpu_policy->cur = cur_freq;
1027         }
1028
1029 out:
1030         cpufreq_cpu_put(cpu_policy);
1031         return 0;
1032 }
1033
1034 /**
1035  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1036  *
1037  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1038  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1039  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1040  *          restored.
1041  */
1042 static int cpufreq_resume(struct sys_device * sysdev)
1043 {
1044         int cpu = sysdev->id;
1045         unsigned int ret = 0;
1046         struct cpufreq_policy *cpu_policy;
1047
1048         dprintk("resuming cpu %u\n", cpu);
1049
1050         if (!cpu_online(cpu))
1051                 return 0;
1052
1053         /* we may be lax here as interrupts are off. Nonetheless
1054          * we need to grab the correct cpu policy, as to check
1055          * whether we really run on this CPU.
1056          */
1057
1058         cpu_policy = cpufreq_cpu_get(cpu);
1059         if (!cpu_policy)
1060                 return -EINVAL;
1061
1062         /* only handle each CPU group once */
1063         if (unlikely(cpu_policy->cpu != cpu)) {
1064                 cpufreq_cpu_put(cpu_policy);
1065                 return 0;
1066         }
1067
1068         if (cpufreq_driver->resume) {
1069                 ret = cpufreq_driver->resume(cpu_policy);
1070                 if (ret) {
1071                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1072                                         "step on CPU %u\n", cpu_policy->cpu);
1073                         cpufreq_cpu_put(cpu_policy);
1074                         return ret;
1075                 }
1076         }
1077
1078         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1079                 unsigned int cur_freq = 0;
1080
1081                 if (cpufreq_driver->get)
1082                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1083
1084                 if (!cur_freq || !cpu_policy->cur) {
1085                         printk(KERN_ERR "cpufreq: resume failed to assert "
1086                                         "current frequency is what timing core "
1087                                         "thinks it is.\n");
1088                         goto out;
1089                 }
1090
1091                 if (unlikely(cur_freq != cpu_policy->cur)) {
1092                         struct cpufreq_freqs freqs;
1093
1094                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1095                                 dprintk("Warning: CPU frequency"
1096                                        "is %u, cpufreq assumed %u kHz.\n",
1097                                        cur_freq, cpu_policy->cur);
1098
1099                         freqs.cpu = cpu;
1100                         freqs.old = cpu_policy->cur;
1101                         freqs.new = cur_freq;
1102
1103                         blocking_notifier_call_chain(
1104                                         &cpufreq_transition_notifier_list,
1105                                         CPUFREQ_RESUMECHANGE, &freqs);
1106                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1107
1108                         cpu_policy->cur = cur_freq;
1109                 }
1110         }
1111
1112 out:
1113         schedule_work(&cpu_policy->update);
1114         cpufreq_cpu_put(cpu_policy);
1115         return ret;
1116 }
1117
1118 static struct sysdev_driver cpufreq_sysdev_driver = {
1119         .add            = cpufreq_add_dev,
1120         .remove         = cpufreq_remove_dev,
1121         .suspend        = cpufreq_suspend,
1122         .resume         = cpufreq_resume,
1123 };
1124
1125
1126 /*********************************************************************
1127  *                     NOTIFIER LISTS INTERFACE                      *
1128  *********************************************************************/
1129
1130 /**
1131  *      cpufreq_register_notifier - register a driver with cpufreq
1132  *      @nb: notifier function to register
1133  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1134  *
1135  *      Add a driver to one of two lists: either a list of drivers that
1136  *      are notified about clock rate changes (once before and once after
1137  *      the transition), or a list of drivers that are notified about
1138  *      changes in cpufreq policy.
1139  *
1140  *      This function may sleep, and has the same return conditions as
1141  *      blocking_notifier_chain_register.
1142  */
1143 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1144 {
1145         int ret;
1146
1147         switch (list) {
1148         case CPUFREQ_TRANSITION_NOTIFIER:
1149                 ret = blocking_notifier_chain_register(
1150                                 &cpufreq_transition_notifier_list, nb);
1151                 break;
1152         case CPUFREQ_POLICY_NOTIFIER:
1153                 ret = blocking_notifier_chain_register(
1154                                 &cpufreq_policy_notifier_list, nb);
1155                 break;
1156         default:
1157                 ret = -EINVAL;
1158         }
1159
1160         return ret;
1161 }
1162 EXPORT_SYMBOL(cpufreq_register_notifier);
1163
1164
1165 /**
1166  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1167  *      @nb: notifier block to be unregistered
1168  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1169  *
1170  *      Remove a driver from the CPU frequency notifier list.
1171  *
1172  *      This function may sleep, and has the same return conditions as
1173  *      blocking_notifier_chain_unregister.
1174  */
1175 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1176 {
1177         int ret;
1178
1179         switch (list) {
1180         case CPUFREQ_TRANSITION_NOTIFIER:
1181                 ret = blocking_notifier_chain_unregister(
1182                                 &cpufreq_transition_notifier_list, nb);
1183                 break;
1184         case CPUFREQ_POLICY_NOTIFIER:
1185                 ret = blocking_notifier_chain_unregister(
1186                                 &cpufreq_policy_notifier_list, nb);
1187                 break;
1188         default:
1189                 ret = -EINVAL;
1190         }
1191
1192         return ret;
1193 }
1194 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1195
1196
1197 /*********************************************************************
1198  *                              GOVERNORS                            *
1199  *********************************************************************/
1200
1201
1202 /* Must be called with lock_cpu_hotplug held */
1203 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1204                             unsigned int target_freq,
1205                             unsigned int relation)
1206 {
1207         int retval = -EINVAL;
1208
1209         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1210                 target_freq, relation);
1211         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1212                 retval = cpufreq_driver->target(policy, target_freq, relation);
1213
1214         return retval;
1215 }
1216 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1217
1218 int cpufreq_driver_target(struct cpufreq_policy *policy,
1219                           unsigned int target_freq,
1220                           unsigned int relation)
1221 {
1222         int ret;
1223
1224         policy = cpufreq_cpu_get(policy->cpu);
1225         if (!policy)
1226                 return -EINVAL;
1227
1228         lock_cpu_hotplug();
1229         mutex_lock(&policy->lock);
1230
1231         ret = __cpufreq_driver_target(policy, target_freq, relation);
1232
1233         mutex_unlock(&policy->lock);
1234         unlock_cpu_hotplug();
1235
1236         cpufreq_cpu_put(policy);
1237         return ret;
1238 }
1239 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1240
1241 /*
1242  * Locking: Must be called with the lock_cpu_hotplug() lock held
1243  * when "event" is CPUFREQ_GOV_LIMITS
1244  */
1245
1246 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1247 {
1248         int ret;
1249
1250         if (!try_module_get(policy->governor->owner))
1251                 return -EINVAL;
1252
1253         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1254         ret = policy->governor->governor(policy, event);
1255
1256         /* we keep one module reference alive for each CPU governed by this CPU */
1257         if ((event != CPUFREQ_GOV_START) || ret)
1258                 module_put(policy->governor->owner);
1259         if ((event == CPUFREQ_GOV_STOP) && !ret)
1260                 module_put(policy->governor->owner);
1261
1262         return ret;
1263 }
1264
1265
1266 int cpufreq_register_governor(struct cpufreq_governor *governor)
1267 {
1268         struct cpufreq_governor *t;
1269
1270         if (!governor)
1271                 return -EINVAL;
1272
1273         mutex_lock(&cpufreq_governor_mutex);
1274
1275         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1276                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1277                         mutex_unlock(&cpufreq_governor_mutex);
1278                         return -EBUSY;
1279                 }
1280         }
1281         list_add(&governor->governor_list, &cpufreq_governor_list);
1282
1283         mutex_unlock(&cpufreq_governor_mutex);
1284         return 0;
1285 }
1286 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1287
1288
1289 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1290 {
1291         if (!governor)
1292                 return;
1293
1294         mutex_lock(&cpufreq_governor_mutex);
1295         list_del(&governor->governor_list);
1296         mutex_unlock(&cpufreq_governor_mutex);
1297         return;
1298 }
1299 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1300
1301
1302
1303 /*********************************************************************
1304  *                          POLICY INTERFACE                         *
1305  *********************************************************************/
1306
1307 /**
1308  * cpufreq_get_policy - get the current cpufreq_policy
1309  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1310  *
1311  * Reads the current cpufreq policy.
1312  */
1313 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1314 {
1315         struct cpufreq_policy *cpu_policy;
1316         if (!policy)
1317                 return -EINVAL;
1318
1319         cpu_policy = cpufreq_cpu_get(cpu);
1320         if (!cpu_policy)
1321                 return -EINVAL;
1322
1323         mutex_lock(&cpu_policy->lock);
1324         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1325         mutex_unlock(&cpu_policy->lock);
1326
1327         cpufreq_cpu_put(cpu_policy);
1328         return 0;
1329 }
1330 EXPORT_SYMBOL(cpufreq_get_policy);
1331
1332
1333 /*
1334  * Locking: Must be called with the lock_cpu_hotplug() lock held
1335  */
1336 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1337 {
1338         int ret = 0;
1339
1340         cpufreq_debug_disable_ratelimit();
1341         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1342                 policy->min, policy->max);
1343
1344         memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo));
1345
1346         /* verify the cpu speed can be set within this limit */
1347         ret = cpufreq_driver->verify(policy);
1348         if (ret)
1349                 goto error_out;
1350
1351         /* adjust if necessary - all reasons */
1352         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1353                         CPUFREQ_ADJUST, policy);
1354
1355         /* adjust if necessary - hardware incompatibility*/
1356         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1357                         CPUFREQ_INCOMPATIBLE, policy);
1358
1359         /* verify the cpu speed can be set within this limit,
1360            which might be different to the first one */
1361         ret = cpufreq_driver->verify(policy);
1362         if (ret)
1363                 goto error_out;
1364
1365         /* notification of the new policy */
1366         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1367                         CPUFREQ_NOTIFY, policy);
1368
1369         data->min = policy->min;
1370         data->max = policy->max;
1371
1372         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1373
1374         if (cpufreq_driver->setpolicy) {
1375                 data->policy = policy->policy;
1376                 dprintk("setting range\n");
1377                 ret = cpufreq_driver->setpolicy(policy);
1378         } else {
1379                 if (policy->governor != data->governor) {
1380                         /* save old, working values */
1381                         struct cpufreq_governor *old_gov = data->governor;
1382
1383                         dprintk("governor switch\n");
1384
1385                         /* end old governor */
1386                         if (data->governor)
1387                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1388
1389                         /* start new governor */
1390                         data->governor = policy->governor;
1391                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1392                                 /* new governor failed, so re-start old one */
1393                                 dprintk("starting governor %s failed\n", data->governor->name);
1394                                 if (old_gov) {
1395                                         data->governor = old_gov;
1396                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1397                                 }
1398                                 ret = -EINVAL;
1399                                 goto error_out;
1400                         }
1401                         /* might be a policy change, too, so fall through */
1402                 }
1403                 dprintk("governor: change or update limits\n");
1404                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1405         }
1406
1407 error_out:
1408         cpufreq_debug_enable_ratelimit();
1409         return ret;
1410 }
1411
1412 /**
1413  *      cpufreq_set_policy - set a new CPUFreq policy
1414  *      @policy: policy to be set.
1415  *
1416  *      Sets a new CPU frequency and voltage scaling policy.
1417  */
1418 int cpufreq_set_policy(struct cpufreq_policy *policy)
1419 {
1420         int ret = 0;
1421         struct cpufreq_policy *data;
1422
1423         if (!policy)
1424                 return -EINVAL;
1425
1426         data = cpufreq_cpu_get(policy->cpu);
1427         if (!data)
1428                 return -EINVAL;
1429
1430         lock_cpu_hotplug();
1431
1432         /* lock this CPU */
1433         mutex_lock(&data->lock);
1434
1435         ret = __cpufreq_set_policy(data, policy);
1436         data->user_policy.min = data->min;
1437         data->user_policy.max = data->max;
1438         data->user_policy.policy = data->policy;
1439         data->user_policy.governor = data->governor;
1440
1441         mutex_unlock(&data->lock);
1442
1443         unlock_cpu_hotplug();
1444         cpufreq_cpu_put(data);
1445
1446         return ret;
1447 }
1448 EXPORT_SYMBOL(cpufreq_set_policy);
1449
1450
1451 /**
1452  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1453  *      @cpu: CPU which shall be re-evaluated
1454  *
1455  *      Usefull for policy notifiers which have different necessities
1456  *      at different times.
1457  */
1458 int cpufreq_update_policy(unsigned int cpu)
1459 {
1460         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1461         struct cpufreq_policy policy;
1462         int ret = 0;
1463
1464         if (!data)
1465                 return -ENODEV;
1466
1467         lock_cpu_hotplug();
1468         mutex_lock(&data->lock);
1469
1470         dprintk("updating policy for CPU %u\n", cpu);
1471         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1472         policy.min = data->user_policy.min;
1473         policy.max = data->user_policy.max;
1474         policy.policy = data->user_policy.policy;
1475         policy.governor = data->user_policy.governor;
1476
1477         /* BIOS might change freq behind our back
1478           -> ask driver for current freq and notify governors about a change */
1479         if (cpufreq_driver->get) {
1480                 policy.cur = cpufreq_driver->get(cpu);
1481                 if (!data->cur) {
1482                         dprintk("Driver did not initialize current freq");
1483                         data->cur = policy.cur;
1484                 } else {
1485                         if (data->cur != policy.cur)
1486                                 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1487                 }
1488         }
1489
1490         ret = __cpufreq_set_policy(data, &policy);
1491
1492         mutex_unlock(&data->lock);
1493         unlock_cpu_hotplug();
1494         cpufreq_cpu_put(data);
1495         return ret;
1496 }
1497 EXPORT_SYMBOL(cpufreq_update_policy);
1498
1499 #ifdef CONFIG_HOTPLUG_CPU
1500 static int cpufreq_cpu_callback(struct notifier_block *nfb,
1501                                         unsigned long action, void *hcpu)
1502 {
1503         unsigned int cpu = (unsigned long)hcpu;
1504         struct cpufreq_policy *policy;
1505         struct sys_device *sys_dev;
1506
1507         sys_dev = get_cpu_sysdev(cpu);
1508
1509         if (sys_dev) {
1510                 switch (action) {
1511                 case CPU_ONLINE:
1512                         cpufreq_add_dev(sys_dev);
1513                         break;
1514                 case CPU_DOWN_PREPARE:
1515                         /*
1516                          * We attempt to put this cpu in lowest frequency
1517                          * possible before going down. This will permit
1518                          * hardware-managed P-State to switch other related
1519                          * threads to min or higher speeds if possible.
1520                          */
1521                         policy = cpufreq_cpu_data[cpu];
1522                         if (policy) {
1523                                 cpufreq_driver_target(policy, policy->min,
1524                                                 CPUFREQ_RELATION_H);
1525                         }
1526                         break;
1527                 case CPU_DEAD:
1528                         cpufreq_remove_dev(sys_dev);
1529                         break;
1530                 }
1531         }
1532         return NOTIFY_OK;
1533 }
1534
1535 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1536 {
1537     .notifier_call = cpufreq_cpu_callback,
1538 };
1539 #endif /* CONFIG_HOTPLUG_CPU */
1540
1541 /*********************************************************************
1542  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1543  *********************************************************************/
1544
1545 /**
1546  * cpufreq_register_driver - register a CPU Frequency driver
1547  * @driver_data: A struct cpufreq_driver containing the values#
1548  * submitted by the CPU Frequency driver.
1549  *
1550  *   Registers a CPU Frequency driver to this core code. This code
1551  * returns zero on success, -EBUSY when another driver got here first
1552  * (and isn't unregistered in the meantime).
1553  *
1554  */
1555 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1556 {
1557         unsigned long flags;
1558         int ret;
1559
1560         if (!driver_data || !driver_data->verify || !driver_data->init ||
1561             ((!driver_data->setpolicy) && (!driver_data->target)))
1562                 return -EINVAL;
1563
1564         dprintk("trying to register driver %s\n", driver_data->name);
1565
1566         if (driver_data->setpolicy)
1567                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1568
1569         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1570         if (cpufreq_driver) {
1571                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1572                 return -EBUSY;
1573         }
1574         cpufreq_driver = driver_data;
1575         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1576
1577         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1578
1579         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1580                 int i;
1581                 ret = -ENODEV;
1582
1583                 /* check for at least one working CPU */
1584                 for (i=0; i<NR_CPUS; i++)
1585                         if (cpufreq_cpu_data[i])
1586                                 ret = 0;
1587
1588                 /* if all ->init() calls failed, unregister */
1589                 if (ret) {
1590                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1591                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1592
1593                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1594                         cpufreq_driver = NULL;
1595                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1596                 }
1597         }
1598
1599         if (!ret) {
1600                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1601                 dprintk("driver %s up and running\n", driver_data->name);
1602                 cpufreq_debug_enable_ratelimit();
1603         }
1604
1605         return (ret);
1606 }
1607 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1608
1609
1610 /**
1611  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1612  *
1613  *    Unregister the current CPUFreq driver. Only call this if you have
1614  * the right to do so, i.e. if you have succeeded in initialising before!
1615  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1616  * currently not initialised.
1617  */
1618 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1619 {
1620         unsigned long flags;
1621
1622         cpufreq_debug_disable_ratelimit();
1623
1624         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1625                 cpufreq_debug_enable_ratelimit();
1626                 return -EINVAL;
1627         }
1628
1629         dprintk("unregistering driver %s\n", driver->name);
1630
1631         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1632         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1633
1634         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1635         cpufreq_driver = NULL;
1636         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1637
1638         return 0;
1639 }
1640 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);