drivers/cpufreq/cpufreq.c

   1 /*
   2  *  linux/drivers/cpufreq/cpufreq.c
   3  *
   4  *  Copyright (C) 2001 Russell King
   5  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
   6  *
   7  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
   8  *      Added handling for CPU hotplug
   9  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
  10  *      Fix handling for CPU hotplug -- affected CPUs
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/config.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/notifier.h>
  23 #include <linux/cpufreq.h>
  24 #include <linux/delay.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/device.h>
  28 #include <linux/slab.h>
  29 #include <linux/cpu.h>
  30 #include <linux/completion.h>
  31 #include <linux/mutex.h>
  32
  33 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
  34
  35 /**
  36  * The "cpufreq driver" - the arch- or hardware-dependend low
  37  * level driver of CPUFreq support, and its spinlock. This lock
  38  * also protects the cpufreq_cpu_data array.
  39  */
  40 static struct cpufreq_driver *cpufreq_driver;
  41 static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
  42 static DEFINE_SPINLOCK(cpufreq_driver_lock);
  43
  44 /* internal prototypes */
  45 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
  46 static void handle_update(void *data);
  47
  48 /**
  49  * Two notifier lists: the "policy" list is involved in the
  50  * validation process for a new CPU frequency policy; the
  51  * "transition" list for kernel code that needs to handle
  52  * changes to devices when the CPU clock speed changes.
  53  * The mutex locks both lists.
  54  */
  55 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
  56 static BLOCKING_NOTIFIER_HEAD(cpufreq_transition_notifier_list);
  57
  58
  59 static LIST_HEAD(cpufreq_governor_list);
  60 static DEFINE_MUTEX (cpufreq_governor_mutex);
  61
  62 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
  63 {
  64         struct cpufreq_policy *data;
  65         unsigned long flags;
  66
  67         if (cpu >= NR_CPUS)
  68                 goto err_out;
  69
  70         /* get the cpufreq driver */
  71         spin_lock_irqsave(&cpufreq_driver_lock, flags);
  72
  73         if (!cpufreq_driver)
  74                 goto err_out_unlock;
  75
  76         if (!try_module_get(cpufreq_driver->owner))
  77                 goto err_out_unlock;
  78
  79
  80         /* get the CPU */
  81         data = cpufreq_cpu_data[cpu];
  82
  83         if (!data)
  84                 goto err_out_put_module;
  85
  86         if (!kobject_get(&data->kobj))
  87                 goto err_out_put_module;
  88
  89         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
  90         return data;
  91
  92 err_out_put_module:
  93         module_put(cpufreq_driver->owner);
  94 err_out_unlock:
  95         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
  96 err_out:
  97         return NULL;
  98 }
  99 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
 100
 101
 102 void cpufreq_cpu_put(struct cpufreq_policy *data)
 103 {
 104         kobject_put(&data->kobj);
 105         module_put(cpufreq_driver->owner);
 106 }
 107 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 108
 109
 110 /*********************************************************************
 111  *                     UNIFIED DEBUG HELPERS                         *
 112  *********************************************************************/
 113 #ifdef CONFIG_CPU_FREQ_DEBUG
 114
 115 /* what part(s) of the CPUfreq subsystem are debugged? */
 116 static unsigned int debug;
 117
 118 /* is the debug output ratelimit'ed using printk_ratelimit? User can
 119  * set or modify this value.
 120  */
 121 static unsigned int debug_ratelimit = 1;
 122
 123 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
 124  * loading of a cpufreq driver, temporarily disabled when a new policy
 125  * is set, and disabled upon cpufreq driver removal
 126  */
 127 static unsigned int disable_ratelimit = 1;
 128 static DEFINE_SPINLOCK(disable_ratelimit_lock);
 129
 130 static void cpufreq_debug_enable_ratelimit(void)
 131 {
 132         unsigned long flags;
 133
 134         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 135         if (disable_ratelimit)
 136                 disable_ratelimit--;
 137         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 138 }
 139
 140 static void cpufreq_debug_disable_ratelimit(void)
 141 {
 142         unsigned long flags;
 143
 144         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 145         disable_ratelimit++;
 146         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 147 }
 148
 149 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
 150 {
 151         char s[256];
 152         va_list args;
 153         unsigned int len;
 154         unsigned long flags;
 155
 156         WARN_ON(!prefix);
 157         if (type & debug) {
 158                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
 159                 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
 160                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 161                         return;
 162                 }
 163                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 164
 165                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
 166
 167                 va_start(args, fmt);
 168                 len += vsnprintf(&s[len], (256 - len), fmt, args);
 169                 va_end(args);
 170
 171                 printk(s);
 172
 173                 WARN_ON(len < 5);
 174         }
 175 }
 176 EXPORT_SYMBOL(cpufreq_debug_printk);
 177
 178
 179 module_param(debug, uint, 0644);
 180 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
 181
 182 module_param(debug_ratelimit, uint, 0644);
 183 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
 184
 185 #else /* !CONFIG_CPU_FREQ_DEBUG */
 186
 187 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
 188 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
 189
 190 #endif /* CONFIG_CPU_FREQ_DEBUG */
 191
 192
 193 /*********************************************************************
 194  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 195  *********************************************************************/
 196
 197 /**
 198  * adjust_jiffies - adjust the system "loops_per_jiffy"
 199  *
 200  * This function alters the system "loops_per_jiffy" for the clock
 201  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 202  * systems as each CPU might be scaled differently. So, use the arch
 203  * per-CPU loops_per_jiffy value wherever possible.
 204  */
 205 #ifndef CONFIG_SMP
 206 static unsigned long l_p_j_ref;
 207 static unsigned int  l_p_j_ref_freq;
 208
 209 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 210 {
 211         if (ci->flags & CPUFREQ_CONST_LOOPS)
 212                 return;
 213
 214         if (!l_p_j_ref_freq) {
 215                 l_p_j_ref = loops_per_jiffy;
 216                 l_p_j_ref_freq = ci->old;
 217                 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 218         }
 219         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
 220             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
 221             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 222                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
 223                 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
 224         }
 225 }
 226 #else
 227 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
 228 #endif
 229
 230
 231 /**
 232  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
 233  * on frequency transition.
 234  *
 235  * This function calls the transition notifiers and the "adjust_jiffies"
 236  * function. It is called twice on all CPU frequency changes that have
 237  * external effects.
 238  */
 239 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 240 {
 241         struct cpufreq_policy *policy;
 242
 243         BUG_ON(irqs_disabled());
 244
 245         freqs->flags = cpufreq_driver->flags;
 246         dprintk("notification %u of frequency transition to %u kHz\n",
 247                 state, freqs->new);
 248
 249         policy = cpufreq_cpu_data[freqs->cpu];
 250         switch (state) {
 251
 252         case CPUFREQ_PRECHANGE:
 253                 /* detect if the driver reported a value as "old frequency"
 254                  * which is not equal to what the cpufreq core thinks is
 255                  * "old frequency".
 256                  */
 257                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 258                         if ((policy) && (policy->cpu == freqs->cpu) &&
 259                             (policy->cur) && (policy->cur != freqs->old)) {
 260                                 dprintk("Warning: CPU frequency is"
 261                                         " %u, cpufreq assumed %u kHz.\n",
 262                                         freqs->old, policy->cur);
 263                                 freqs->old = policy->cur;
 264                         }
 265                 }
 266                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
 267                                 CPUFREQ_PRECHANGE, freqs);
 268                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 269                 break;
 270
 271         case CPUFREQ_POSTCHANGE:
 272                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 273                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
 274                                 CPUFREQ_POSTCHANGE, freqs);
 275                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
 276                         policy->cur = freqs->new;
 277                 break;
 278         }
 279 }
 280 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
 281
 282
 283
 284 /*********************************************************************
 285  *                          SYSFS INTERFACE                          *
 286  *********************************************************************/
 287
 288 /**
 289  * cpufreq_parse_governor - parse a governor string
 290  */
 291 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
 292                                 struct cpufreq_governor **governor)
 293 {
 294         if (!cpufreq_driver)
 295                 return -EINVAL;
 296         if (cpufreq_driver->setpolicy) {
 297                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
 298                         *policy = CPUFREQ_POLICY_PERFORMANCE;
 299                         return 0;
 300                 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
 301                         *policy = CPUFREQ_POLICY_POWERSAVE;
 302                         return 0;
 303                 }
 304                 return -EINVAL;
 305         } else {
 306                 struct cpufreq_governor *t;
 307                 mutex_lock(&cpufreq_governor_mutex);
 308                 if (!cpufreq_driver || !cpufreq_driver->target)
 309                         goto out;
 310                 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 311                         if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
 312                                 *governor = t;
 313                                 mutex_unlock(&cpufreq_governor_mutex);
 314                                 return 0;
 315                         }
 316                 }
 317 out:
 318                 mutex_unlock(&cpufreq_governor_mutex);
 319         }
 320         return -EINVAL;
 321 }
 322
 323
 324 /* drivers/base/cpu.c */
 325 extern struct sysdev_class cpu_sysdev_class;
 326
 327
 328 /**
 329  * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
 330  *
 331  * Write out information from cpufreq_driver->policy[cpu]; object must be
 332  * "unsigned int".
 333  */
 334
 335 #define show_one(file_name, object)                     \
 336 static ssize_t show_##file_name                         \
 337 (struct cpufreq_policy * policy, char *buf)             \
 338 {                                                       \
 339         return sprintf (buf, "%u\n", policy->object);   \
 340 }
 341
 342 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 343 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 344 show_one(scaling_min_freq, min);
 345 show_one(scaling_max_freq, max);
 346 show_one(scaling_cur_freq, cur);
 347
 348 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy);
 349
 350 /**
 351  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 352  */
 353 #define store_one(file_name, object)                    \
 354 static ssize_t store_##file_name                                        \
 355 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
 356 {                                                                       \
 357         unsigned int ret = -EINVAL;                                     \
 358         struct cpufreq_policy new_policy;                               \
 359                                                                         \
 360         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
 361         if (ret)                                                        \
 362                 return -EINVAL;                                         \
 363                                                                         \
 364         ret = sscanf (buf, "%u", &new_policy.object);                   \
 365         if (ret != 1)                                                   \
 366                 return -EINVAL;                                         \
 367                                                                         \
 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                                                                         \
 373         return ret ? ret : count;                                       \
 374 }
 375
 376 store_one(scaling_min_freq,min);
 377 store_one(scaling_max_freq,max);
 378
 379 /**
 380  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 381  */
 382 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
 383 {
 384         unsigned int cur_freq = cpufreq_get(policy->cpu);
 385         if (!cur_freq)
 386                 return sprintf(buf, "<unknown>");
 387         return sprintf(buf, "%u\n", cur_freq);
 388 }
 389
 390
 391 /**
 392  * show_scaling_governor - show the current policy for the specified CPU
 393  */
 394 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
 395 {
 396         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
 397                 return sprintf(buf, "powersave\n");
 398         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 399                 return sprintf(buf, "performance\n");
 400         else if (policy->governor)
 401                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
 402         return -EINVAL;
 403 }
 404
 405
 406 /**
 407  * store_scaling_governor - store policy for the specified CPU
 408  */
 409 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
 410                                        const char *buf, size_t count)
 411 {
 412         unsigned int ret = -EINVAL;
 413         char    str_governor[16];
 414         struct cpufreq_policy new_policy;
 415
 416         ret = cpufreq_get_policy(&new_policy, policy->cpu);
 417         if (ret)
 418                 return ret;
 419
 420         ret = sscanf (buf, "%15s", str_governor);
 421         if (ret != 1)
 422                 return -EINVAL;
 423
 424         if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
 425                 return -EINVAL;
 426
 427         /* Do not use cpufreq_set_policy here or the user_policy.max
 428            will be wrongly overridden */
 429         mutex_lock(&policy->lock);
 430         ret = __cpufreq_set_policy(policy, &new_policy);
 431
 432         policy->user_policy.policy = policy->policy;
 433         policy->user_policy.governor = policy->governor;
 434         mutex_unlock(&policy->lock);
 435
 436         return ret ? ret : count;
 437 }
 438
 439 /**
 440  * show_scaling_driver - show the cpufreq driver currently loaded
 441  */
 442 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
 443 {
 444         return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
 445 }
 446
 447 /**
 448  * show_scaling_available_governors - show the available CPUfreq governors
 449  */
 450 static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
 451                                 char *buf)
 452 {
 453         ssize_t i = 0;
 454         struct cpufreq_governor *t;
 455
 456         if (!cpufreq_driver->target) {
 457                 i += sprintf(buf, "performance powersave");
 458                 goto out;
 459         }
 460
 461         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 462                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
 463                         goto out;
 464                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
 465         }
 466 out:
 467         i += sprintf(&buf[i], "\n");
 468         return i;
 469 }
 470 /**
 471  * show_affected_cpus - show the CPUs affected by each transition
 472  */
 473 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
 474 {
 475         ssize_t i = 0;
 476         unsigned int cpu;
 477
 478         for_each_cpu_mask(cpu, policy->cpus) {
 479                 if (i)
 480                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 481                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 482                 if (i >= (PAGE_SIZE - 5))
 483                     break;
 484         }
 485         i += sprintf(&buf[i], "\n");
 486         return i;
 487 }
 488
 489
 490 #define define_one_ro(_name) \
 491 static struct freq_attr _name = \
 492 __ATTR(_name, 0444, show_##_name, NULL)
 493
 494 #define define_one_ro0400(_name) \
 495 static struct freq_attr _name = \
 496 __ATTR(_name, 0400, show_##_name, NULL)
 497
 498 #define define_one_rw(_name) \
 499 static struct freq_attr _name = \
 500 __ATTR(_name, 0644, show_##_name, store_##_name)
 501
 502 define_one_ro0400(cpuinfo_cur_freq);
 503 define_one_ro(cpuinfo_min_freq);
 504 define_one_ro(cpuinfo_max_freq);
 505 define_one_ro(scaling_available_governors);
 506 define_one_ro(scaling_driver);
 507 define_one_ro(scaling_cur_freq);
 508 define_one_ro(affected_cpus);
 509 define_one_rw(scaling_min_freq);
 510 define_one_rw(scaling_max_freq);
 511 define_one_rw(scaling_governor);
 512
 513 static struct attribute * default_attrs[] = {
 514         &cpuinfo_min_freq.attr,
 515         &cpuinfo_max_freq.attr,
 516         &scaling_min_freq.attr,
 517         &scaling_max_freq.attr,
 518         &affected_cpus.attr,
 519         &scaling_governor.attr,
 520         &scaling_driver.attr,
 521         &scaling_available_governors.attr,
 522         NULL
 523 };
 524
 525 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
 526 #define to_attr(a) container_of(a,struct freq_attr,attr)
 527
 528 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
 529 {
 530         struct cpufreq_policy * policy = to_policy(kobj);
 531         struct freq_attr * fattr = to_attr(attr);
 532         ssize_t ret;
 533         policy = cpufreq_cpu_get(policy->cpu);
 534         if (!policy)
 535                 return -EINVAL;
 536         ret = fattr->show ? fattr->show(policy,buf) : -EIO;
 537         cpufreq_cpu_put(policy);
 538         return ret;
 539 }
 540
 541 static ssize_t store(struct kobject * kobj, struct attribute * attr,
 542                      const char * buf, size_t count)
 543 {
 544         struct cpufreq_policy * policy = to_policy(kobj);
 545         struct freq_attr * fattr = to_attr(attr);
 546         ssize_t ret;
 547         policy = cpufreq_cpu_get(policy->cpu);
 548         if (!policy)
 549                 return -EINVAL;
 550         ret = fattr->store ? fattr->store(policy,buf,count) : -EIO;
 551         cpufreq_cpu_put(policy);
 552         return ret;
 553 }
 554
 555 static void cpufreq_sysfs_release(struct kobject * kobj)
 556 {
 557         struct cpufreq_policy * policy = to_policy(kobj);
 558         dprintk("last reference is dropped\n");
 559         complete(&policy->kobj_unregister);
 560 }
 561
 562 static struct sysfs_ops sysfs_ops = {
 563         .show   = show,
 564         .store  = store,
 565 };
 566
 567 static struct kobj_type ktype_cpufreq = {
 568         .sysfs_ops      = &sysfs_ops,
 569         .default_attrs  = default_attrs,
 570         .release        = cpufreq_sysfs_release,
 571 };
 572
 573
 574 /**
 575  * cpufreq_add_dev - add a CPU device
 576  *
 577  * Adds the cpufreq interface for a CPU device.
 578  */
 579 static int cpufreq_add_dev (struct sys_device * sys_dev)
 580 {
 581         unsigned int cpu = sys_dev->id;
 582         int ret = 0;
 583         struct cpufreq_policy new_policy;
 584         struct cpufreq_policy *policy;
 585         struct freq_attr **drv_attr;
 586         struct sys_device *cpu_sys_dev;
 587         unsigned long flags;
 588         unsigned int j;
 589 #ifdef CONFIG_SMP
 590         struct cpufreq_policy *managed_policy;
 591 #endif
 592
 593         if (cpu_is_offline(cpu))
 594                 return 0;
 595
 596         cpufreq_debug_disable_ratelimit();
 597         dprintk("adding CPU %u\n", cpu);
 598
 599 #ifdef CONFIG_SMP
 600         /* check whether a different CPU already registered this
 601          * CPU because it is in the same boat. */
 602         policy = cpufreq_cpu_get(cpu);
 603         if (unlikely(policy)) {
 604                 cpufreq_cpu_put(policy);
 605                 cpufreq_debug_enable_ratelimit();
 606                 return 0;
 607         }
 608 #endif
 609
 610         if (!try_module_get(cpufreq_driver->owner)) {
 611                 ret = -EINVAL;
 612                 goto module_out;
 613         }
 614
 615         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
 616         if (!policy) {
 617                 ret = -ENOMEM;
 618                 goto nomem_out;
 619         }
 620
 621         policy->cpu = cpu;
 622         policy->cpus = cpumask_of_cpu(cpu);
 623
 624         mutex_init(&policy->lock);
 625         mutex_lock(&policy->lock);
 626         init_completion(&policy->kobj_unregister);
 627         INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
 628
 629         /* call driver. From then on the cpufreq must be able
 630          * to accept all calls to ->verify and ->setpolicy for this CPU
 631          */
 632         ret = cpufreq_driver->init(policy);
 633         if (ret) {
 634                 dprintk("initialization failed\n");
 635                 mutex_unlock(&policy->lock);
 636                 goto err_out;
 637         }
 638
 639 #ifdef CONFIG_SMP
 640         for_each_cpu_mask(j, policy->cpus) {
 641                 if (cpu == j)
 642                         continue;
 643
 644                 /* check for existing affected CPUs.  They may not be aware
 645                  * of it due to CPU Hotplug.
 646                  */
 647                 managed_policy = cpufreq_cpu_get(j);
 648                 if (unlikely(managed_policy)) {
 649                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 650                         managed_policy->cpus = policy->cpus;
 651                         cpufreq_cpu_data[cpu] = managed_policy;
 652                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 653
 654                         dprintk("CPU already managed, adding link\n");
 655                         sysfs_create_link(&sys_dev->kobj,
 656                                           &managed_policy->kobj, "cpufreq");
 657
 658                         cpufreq_debug_enable_ratelimit();
 659                         mutex_unlock(&policy->lock);
 660                         ret = 0;
 661                         goto err_out_driver_exit; /* call driver->exit() */
 662                 }
 663         }
 664 #endif
 665         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
 666
 667         /* prepare interface data */
 668         policy->kobj.parent = &sys_dev->kobj;
 669         policy->kobj.ktype = &ktype_cpufreq;
 670         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
 671
 672         ret = kobject_register(&policy->kobj);
 673         if (ret) {
 674                 mutex_unlock(&policy->lock);
 675                 goto err_out_driver_exit;
 676         }
 677         /* set up files for this cpu device */
 678         drv_attr = cpufreq_driver->attr;
 679         while ((drv_attr) && (*drv_attr)) {
 680                 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 681                 drv_attr++;
 682         }
 683         if (cpufreq_driver->get)
 684                 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
 685         if (cpufreq_driver->target)
 686                 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 687
 688         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 689         for_each_cpu_mask(j, policy->cpus)
 690                 cpufreq_cpu_data[j] = policy;
 691         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 692
 693         /* symlink affected CPUs */
 694         for_each_cpu_mask(j, policy->cpus) {
 695                 if (j == cpu)
 696                         continue;
 697                 if (!cpu_online(j))
 698                         continue;
 699
 700                 dprintk("CPU %u already managed, adding link\n", j);
 701                 cpufreq_cpu_get(cpu);
 702                 cpu_sys_dev = get_cpu_sysdev(j);
 703                 sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
 704                                   "cpufreq");
 705         }
 706
 707         policy->governor = NULL; /* to assure that the starting sequence is
 708                                   * run in cpufreq_set_policy */
 709         mutex_unlock(&policy->lock);
 710
 711         /* set default policy */
 712         ret = cpufreq_set_policy(&new_policy);
 713         if (ret) {
 714                 dprintk("setting policy failed\n");
 715                 goto err_out_unregister;
 716         }
 717
 718         module_put(cpufreq_driver->owner);
 719         dprintk("initialization complete\n");
 720         cpufreq_debug_enable_ratelimit();
 721
 722         return 0;
 723
 724
 725 err_out_unregister:
 726         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 727         for_each_cpu_mask(j, policy->cpus)
 728                 cpufreq_cpu_data[j] = NULL;
 729         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 730
 731         kobject_unregister(&policy->kobj);
 732         wait_for_completion(&policy->kobj_unregister);
 733
 734 err_out_driver_exit:
 735         if (cpufreq_driver->exit)
 736                 cpufreq_driver->exit(policy);
 737
 738 err_out:
 739         kfree(policy);
 740
 741 nomem_out:
 742         module_put(cpufreq_driver->owner);
 743 module_out:
 744         cpufreq_debug_enable_ratelimit();
 745         return ret;
 746 }
 747
 748
 749 /**
 750  * cpufreq_remove_dev - remove a CPU device
 751  *
 752  * Removes the cpufreq interface for a CPU device.
 753  */
 754 static int cpufreq_remove_dev (struct sys_device * sys_dev)
 755 {
 756         unsigned int cpu = sys_dev->id;
 757         unsigned long flags;
 758         struct cpufreq_policy *data;
 759 #ifdef CONFIG_SMP
 760         struct sys_device *cpu_sys_dev;
 761         unsigned int j;
 762 #endif
 763
 764         cpufreq_debug_disable_ratelimit();
 765         dprintk("unregistering CPU %u\n", cpu);
 766
 767         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 768         data = cpufreq_cpu_data[cpu];
 769
 770         if (!data) {
 771                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 772                 cpufreq_debug_enable_ratelimit();
 773                 return -EINVAL;
 774         }
 775         cpufreq_cpu_data[cpu] = NULL;
 776
 777
 778 #ifdef CONFIG_SMP
 779         /* if this isn't the CPU which is the parent of the kobj, we
 780          * only need to unlink, put and exit
 781          */
 782         if (unlikely(cpu != data->cpu)) {
 783                 dprintk("removing link\n");
 784                 cpu_clear(cpu, data->cpus);
 785                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 786                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
 787                 cpufreq_cpu_put(data);
 788                 cpufreq_debug_enable_ratelimit();
 789                 return 0;
 790         }
 791 #endif
 792
 793
 794         if (!kobject_get(&data->kobj)) {
 795                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 796                 cpufreq_debug_enable_ratelimit();
 797                 return -EFAULT;
 798         }
 799
 800 #ifdef CONFIG_SMP
 801         /* if we have other CPUs still registered, we need to unlink them,
 802          * or else wait_for_completion below will lock up. Clean the
 803          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
 804          * links afterwards.
 805          */
 806         if (unlikely(cpus_weight(data->cpus) > 1)) {
 807                 for_each_cpu_mask(j, data->cpus) {
 808                         if (j == cpu)
 809                                 continue;
 810                         cpufreq_cpu_data[j] = NULL;
 811                 }
 812         }
 813
 814         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 815
 816         if (unlikely(cpus_weight(data->cpus) > 1)) {
 817                 for_each_cpu_mask(j, data->cpus) {
 818                         if (j == cpu)
 819                                 continue;
 820                         dprintk("removing link for cpu %u\n", j);
 821                         cpu_sys_dev = get_cpu_sysdev(j);
 822                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
 823                         cpufreq_cpu_put(data);
 824                 }
 825         }
 826 #else
 827         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 828 #endif
 829
 830         mutex_lock(&data->lock);
 831         if (cpufreq_driver->target)
 832                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
 833         mutex_unlock(&data->lock);
 834
 835         kobject_unregister(&data->kobj);
 836
 837         kobject_put(&data->kobj);
 838
 839         /* we need to make sure that the underlying kobj is actually
 840          * not referenced anymore by anybody before we proceed with
 841          * unloading.
 842          */
 843         dprintk("waiting for dropping of refcount\n");
 844         wait_for_completion(&data->kobj_unregister);
 845         dprintk("wait complete\n");
 846
 847         if (cpufreq_driver->exit)
 848                 cpufreq_driver->exit(data);
 849
 850         kfree(data);
 851
 852         cpufreq_debug_enable_ratelimit();
 853         return 0;
 854 }
 855
 856
 857 static void handle_update(void *data)
 858 {
 859         unsigned int cpu = (unsigned int)(long)data;
 860         dprintk("handle_update for cpu %u called\n", cpu);
 861         cpufreq_update_policy(cpu);
 862 }
 863
 864 /**
 865  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
 866  *      @cpu: cpu number
 867  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
 868  *      @new_freq: CPU frequency the CPU actually runs at
 869  *
 870  *      We adjust to current frequency first, and need to clean up later. So either call
 871  *      to cpufreq_update_policy() or schedule handle_update()).
 872  */
 873 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
 874 {
 875         struct cpufreq_freqs freqs;
 876
 877         dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
 878                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
 879
 880         freqs.cpu = cpu;
 881         freqs.old = old_freq;
 882         freqs.new = new_freq;
 883         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 884         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 885 }
 886
 887
 888 /**
 889  * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
 890  * @cpu: CPU number
 891  *
 892  * This is the last known freq, without actually getting it from the driver.
 893  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
 894  */
 895 unsigned int cpufreq_quick_get(unsigned int cpu)
 896 {
 897         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 898         unsigned int ret = 0;
 899
 900         if (policy) {
 901                 mutex_lock(&policy->lock);
 902                 ret = policy->cur;
 903                 mutex_unlock(&policy->lock);
 904                 cpufreq_cpu_put(policy);
 905         }
 906
 907         return (ret);
 908 }
 909 EXPORT_SYMBOL(cpufreq_quick_get);
 910
 911
 912 /**
 913  * cpufreq_get - get the current CPU frequency (in kHz)
 914  * @cpu: CPU number
 915  *
 916  * Get the CPU current (static) CPU frequency
 917  */
 918 unsigned int cpufreq_get(unsigned int cpu)
 919 {
 920         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 921         unsigned int ret = 0;
 922
 923         if (!policy)
 924                 return 0;
 925
 926         if (!cpufreq_driver->get)
 927                 goto out;
 928
 929         mutex_lock(&policy->lock);
 930
 931         ret = cpufreq_driver->get(cpu);
 932
 933         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 934                 /* verify no discrepancy between actual and saved value exists */
 935                 if (unlikely(ret != policy->cur)) {
 936                         cpufreq_out_of_sync(cpu, policy->cur, ret);
 937                         schedule_work(&policy->update);
 938                 }
 939         }
 940
 941         mutex_unlock(&policy->lock);
 942
 943 out:
 944         cpufreq_cpu_put(policy);
 945
 946         return (ret);
 947 }
 948 EXPORT_SYMBOL(cpufreq_get);
 949
 950
 951 /**
 952  *      cpufreq_suspend - let the low level driver prepare for suspend
 953  */
 954
 955 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
 956 {
 957         int cpu = sysdev->id;
 958         unsigned int ret = 0;
 959         unsigned int cur_freq = 0;
 960         struct cpufreq_policy *cpu_policy;
 961
 962         dprintk("resuming cpu %u\n", cpu);
 963
 964         if (!cpu_online(cpu))
 965                 return 0;
 966
 967         /* we may be lax here as interrupts are off. Nonetheless
 968          * we need to grab the correct cpu policy, as to check
 969          * whether we really run on this CPU.
 970          */
 971
 972         cpu_policy = cpufreq_cpu_get(cpu);
 973         if (!cpu_policy)
 974                 return -EINVAL;
 975
 976         /* only handle each CPU group once */
 977         if (unlikely(cpu_policy->cpu != cpu)) {
 978                 cpufreq_cpu_put(cpu_policy);
 979                 return 0;
 980         }
 981
 982         if (cpufreq_driver->suspend) {
 983                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
 984                 if (ret) {
 985                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
 986                                         "step on CPU %u\n", cpu_policy->cpu);
 987                         cpufreq_cpu_put(cpu_policy);
 988                         return ret;
 989                 }
 990         }
 991
 992
 993         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
 994                 goto out;
 995
 996         if (cpufreq_driver->get)
 997                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
 998
 999         if (!cur_freq || !cpu_policy->cur) {
1000                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1001                        "frequency is what timing core thinks it is.\n");
1002                 goto out;
1003         }
1004
1005         if (unlikely(cur_freq != cpu_policy->cur)) {
1006                 struct cpufreq_freqs freqs;
1007
1008                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1009                         dprintk("Warning: CPU frequency is %u, "
1010                                "cpufreq assumed %u kHz.\n",
1011                                cur_freq, cpu_policy->cur);
1012
1013                 freqs.cpu = cpu;
1014                 freqs.old = cpu_policy->cur;
1015                 freqs.new = cur_freq;
1016
1017                 blocking_notifier_call_chain(&cpufreq_transition_notifier_list,
1018                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1019                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1020
1021                 cpu_policy->cur = cur_freq;
1022         }
1023
1024 out:
1025         cpufreq_cpu_put(cpu_policy);
1026         return 0;
1027 }
1028
1029 /**
1030  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1031  *
1032  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1033  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1034  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1035  *          restored.
1036  */
1037 static int cpufreq_resume(struct sys_device * sysdev)
1038 {
1039         int cpu = sysdev->id;
1040         unsigned int ret = 0;
1041         struct cpufreq_policy *cpu_policy;
1042
1043         dprintk("resuming cpu %u\n", cpu);
1044
1045         if (!cpu_online(cpu))
1046                 return 0;
1047
1048         /* we may be lax here as interrupts are off. Nonetheless
1049          * we need to grab the correct cpu policy, as to check
1050          * whether we really run on this CPU.
1051          */
1052
1053         cpu_policy = cpufreq_cpu_get(cpu);
1054         if (!cpu_policy)
1055                 return -EINVAL;
1056
1057         /* only handle each CPU group once */
1058         if (unlikely(cpu_policy->cpu != cpu)) {
1059                 cpufreq_cpu_put(cpu_policy);
1060                 return 0;
1061         }
1062
1063         if (cpufreq_driver->resume) {
1064                 ret = cpufreq_driver->resume(cpu_policy);
1065                 if (ret) {
1066                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1067                                         "step on CPU %u\n", cpu_policy->cpu);
1068                         cpufreq_cpu_put(cpu_policy);
1069                         return ret;
1070                 }
1071         }
1072
1073         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1074                 unsigned int cur_freq = 0;
1075
1076                 if (cpufreq_driver->get)
1077                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1078
1079                 if (!cur_freq || !cpu_policy->cur) {
1080                         printk(KERN_ERR "cpufreq: resume failed to assert "
1081                                         "current frequency is what timing core "
1082                                         "thinks it is.\n");
1083                         goto out;
1084                 }
1085
1086                 if (unlikely(cur_freq != cpu_policy->cur)) {
1087                         struct cpufreq_freqs freqs;
1088
1089                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1090                                 dprintk("Warning: CPU frequency"
1091                                        "is %u, cpufreq assumed %u kHz.\n",
1092                                        cur_freq, cpu_policy->cur);
1093
1094                         freqs.cpu = cpu;
1095                         freqs.old = cpu_policy->cur;
1096                         freqs.new = cur_freq;
1097
1098                         blocking_notifier_call_chain(
1099                                         &cpufreq_transition_notifier_list,
1100                                         CPUFREQ_RESUMECHANGE, &freqs);
1101                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1102
1103                         cpu_policy->cur = cur_freq;
1104                 }
1105         }
1106
1107 out:
1108         schedule_work(&cpu_policy->update);
1109         cpufreq_cpu_put(cpu_policy);
1110         return ret;
1111 }
1112
1113 static struct sysdev_driver cpufreq_sysdev_driver = {
1114         .add            = cpufreq_add_dev,
1115         .remove         = cpufreq_remove_dev,
1116         .suspend        = cpufreq_suspend,
1117         .resume         = cpufreq_resume,
1118 };
1119
1120
1121 /*********************************************************************
1122  *                     NOTIFIER LISTS INTERFACE                      *
1123  *********************************************************************/
1124
1125 /**
1126  *      cpufreq_register_notifier - register a driver with cpufreq
1127  *      @nb: notifier function to register
1128  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1129  *
1130  *      Add a driver to one of two lists: either a list of drivers that
1131  *      are notified about clock rate changes (once before and once after
1132  *      the transition), or a list of drivers that are notified about
1133  *      changes in cpufreq policy.
1134  *
1135  *      This function may sleep, and has the same return conditions as
1136  *      blocking_notifier_chain_register.
1137  */
1138 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1139 {
1140         int ret;
1141
1142         switch (list) {
1143         case CPUFREQ_TRANSITION_NOTIFIER:
1144                 ret = blocking_notifier_chain_register(
1145                                 &cpufreq_transition_notifier_list, nb);
1146                 break;
1147         case CPUFREQ_POLICY_NOTIFIER:
1148                 ret = blocking_notifier_chain_register(
1149                                 &cpufreq_policy_notifier_list, nb);
1150                 break;
1151         default:
1152                 ret = -EINVAL;
1153         }
1154
1155         return ret;
1156 }
1157 EXPORT_SYMBOL(cpufreq_register_notifier);
1158
1159
1160 /**
1161  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1162  *      @nb: notifier block to be unregistered
1163  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1164  *
1165  *      Remove a driver from the CPU frequency notifier list.
1166  *
1167  *      This function may sleep, and has the same return conditions as
1168  *      blocking_notifier_chain_unregister.
1169  */
1170 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1171 {
1172         int ret;
1173
1174         switch (list) {
1175         case CPUFREQ_TRANSITION_NOTIFIER:
1176                 ret = blocking_notifier_chain_unregister(
1177                                 &cpufreq_transition_notifier_list, nb);
1178                 break;
1179         case CPUFREQ_POLICY_NOTIFIER:
1180                 ret = blocking_notifier_chain_unregister(
1181                                 &cpufreq_policy_notifier_list, nb);
1182                 break;
1183         default:
1184                 ret = -EINVAL;
1185         }
1186
1187         return ret;
1188 }
1189 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1190
1191
1192 /*********************************************************************
1193  *                              GOVERNORS                            *
1194  *********************************************************************/
1195
1196
1197 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1198                             unsigned int target_freq,
1199                             unsigned int relation)
1200 {
1201         int retval = -EINVAL;
1202
1203         lock_cpu_hotplug();
1204         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1205                 target_freq, relation);
1206         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1207                 retval = cpufreq_driver->target(policy, target_freq, relation);
1208
1209         unlock_cpu_hotplug();
1210
1211         return retval;
1212 }
1213 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1214
1215 int cpufreq_driver_target(struct cpufreq_policy *policy,
1216                           unsigned int target_freq,
1217                           unsigned int relation)
1218 {
1219         int ret;
1220
1221         policy = cpufreq_cpu_get(policy->cpu);
1222         if (!policy)
1223                 return -EINVAL;
1224
1225         mutex_lock(&policy->lock);
1226
1227         ret = __cpufreq_driver_target(policy, target_freq, relation);
1228
1229         mutex_unlock(&policy->lock);
1230
1231         cpufreq_cpu_put(policy);
1232         return ret;
1233 }
1234 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1235
1236
1237 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1238 {
1239         int ret;
1240
1241         if (!try_module_get(policy->governor->owner))
1242                 return -EINVAL;
1243
1244         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1245         ret = policy->governor->governor(policy, event);
1246
1247         /* we keep one module reference alive for each CPU governed by this CPU */
1248         if ((event != CPUFREQ_GOV_START) || ret)
1249                 module_put(policy->governor->owner);
1250         if ((event == CPUFREQ_GOV_STOP) && !ret)
1251                 module_put(policy->governor->owner);
1252
1253         return ret;
1254 }
1255
1256
1257 int cpufreq_governor(unsigned int cpu, unsigned int event)
1258 {
1259         int ret = 0;
1260         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1261
1262         if (!policy)
1263                 return -EINVAL;
1264
1265         mutex_lock(&policy->lock);
1266         ret = __cpufreq_governor(policy, event);
1267         mutex_unlock(&policy->lock);
1268
1269         cpufreq_cpu_put(policy);
1270         return ret;
1271 }
1272 EXPORT_SYMBOL_GPL(cpufreq_governor);
1273
1274
1275 int cpufreq_register_governor(struct cpufreq_governor *governor)
1276 {
1277         struct cpufreq_governor *t;
1278
1279         if (!governor)
1280                 return -EINVAL;
1281
1282         mutex_lock(&cpufreq_governor_mutex);
1283
1284         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1285                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1286                         mutex_unlock(&cpufreq_governor_mutex);
1287                         return -EBUSY;
1288                 }
1289         }
1290         list_add(&governor->governor_list, &cpufreq_governor_list);
1291
1292         mutex_unlock(&cpufreq_governor_mutex);
1293         return 0;
1294 }
1295 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1296
1297
1298 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1299 {
1300         if (!governor)
1301                 return;
1302
1303         mutex_lock(&cpufreq_governor_mutex);
1304         list_del(&governor->governor_list);
1305         mutex_unlock(&cpufreq_governor_mutex);
1306         return;
1307 }
1308 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1309
1310
1311
1312 /*********************************************************************
1313  *                          POLICY INTERFACE                         *
1314  *********************************************************************/
1315
1316 /**
1317  * cpufreq_get_policy - get the current cpufreq_policy
1318  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1319  *
1320  * Reads the current cpufreq policy.
1321  */
1322 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1323 {
1324         struct cpufreq_policy *cpu_policy;
1325         if (!policy)
1326                 return -EINVAL;
1327
1328         cpu_policy = cpufreq_cpu_get(cpu);
1329         if (!cpu_policy)
1330                 return -EINVAL;
1331
1332         mutex_lock(&cpu_policy->lock);
1333         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1334         mutex_unlock(&cpu_policy->lock);
1335
1336         cpufreq_cpu_put(cpu_policy);
1337         return 0;
1338 }
1339 EXPORT_SYMBOL(cpufreq_get_policy);
1340
1341
1342 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1343 {
1344         int ret = 0;
1345
1346         cpufreq_debug_disable_ratelimit();
1347         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1348                 policy->min, policy->max);
1349
1350         memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo));
1351
1352         /* verify the cpu speed can be set within this limit */
1353         ret = cpufreq_driver->verify(policy);
1354         if (ret)
1355                 goto error_out;
1356
1357         /* adjust if necessary - all reasons */
1358         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1359                         CPUFREQ_ADJUST, policy);
1360
1361         /* adjust if necessary - hardware incompatibility*/
1362         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1363                         CPUFREQ_INCOMPATIBLE, policy);
1364
1365         /* verify the cpu speed can be set within this limit,
1366            which might be different to the first one */
1367         ret = cpufreq_driver->verify(policy);
1368         if (ret)
1369                 goto error_out;
1370
1371         /* notification of the new policy */
1372         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1373                         CPUFREQ_NOTIFY, policy);
1374
1375         data->min = policy->min;
1376         data->max = policy->max;
1377
1378         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1379
1380         if (cpufreq_driver->setpolicy) {
1381                 data->policy = policy->policy;
1382                 dprintk("setting range\n");
1383                 ret = cpufreq_driver->setpolicy(policy);
1384         } else {
1385                 if (policy->governor != data->governor) {
1386                         /* save old, working values */
1387                         struct cpufreq_governor *old_gov = data->governor;
1388
1389                         dprintk("governor switch\n");
1390
1391                         /* end old governor */
1392                         if (data->governor)
1393                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1394
1395                         /* start new governor */
1396                         data->governor = policy->governor;
1397                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1398                                 /* new governor failed, so re-start old one */
1399                                 dprintk("starting governor %s failed\n", data->governor->name);
1400                                 if (old_gov) {
1401                                         data->governor = old_gov;
1402                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1403                                 }
1404                                 ret = -EINVAL;
1405                                 goto error_out;
1406                         }
1407                         /* might be a policy change, too, so fall through */
1408                 }
1409                 dprintk("governor: change or update limits\n");
1410                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1411         }
1412
1413 error_out:
1414         cpufreq_debug_enable_ratelimit();
1415         return ret;
1416 }
1417
1418 /**
1419  *      cpufreq_set_policy - set a new CPUFreq policy
1420  *      @policy: policy to be set.
1421  *
1422  *      Sets a new CPU frequency and voltage scaling policy.
1423  */
1424 int cpufreq_set_policy(struct cpufreq_policy *policy)
1425 {
1426         int ret = 0;
1427         struct cpufreq_policy *data;
1428
1429         if (!policy)
1430                 return -EINVAL;
1431
1432         data = cpufreq_cpu_get(policy->cpu);
1433         if (!data)
1434                 return -EINVAL;
1435
1436         /* lock this CPU */
1437         mutex_lock(&data->lock);
1438
1439         ret = __cpufreq_set_policy(data, policy);
1440         data->user_policy.min = data->min;
1441         data->user_policy.max = data->max;
1442         data->user_policy.policy = data->policy;
1443         data->user_policy.governor = data->governor;
1444
1445         mutex_unlock(&data->lock);
1446         cpufreq_cpu_put(data);
1447
1448         return ret;
1449 }
1450 EXPORT_SYMBOL(cpufreq_set_policy);
1451
1452
1453 /**
1454  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1455  *      @cpu: CPU which shall be re-evaluated
1456  *
1457  *      Usefull for policy notifiers which have different necessities
1458  *      at different times.
1459  */
1460 int cpufreq_update_policy(unsigned int cpu)
1461 {
1462         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1463         struct cpufreq_policy policy;
1464         int ret = 0;
1465
1466         if (!data)
1467                 return -ENODEV;
1468
1469         mutex_lock(&data->lock);
1470
1471         dprintk("updating policy for CPU %u\n", cpu);
1472         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1473         policy.min = data->user_policy.min;
1474         policy.max = data->user_policy.max;
1475         policy.policy = data->user_policy.policy;
1476         policy.governor = data->user_policy.governor;
1477
1478         /* BIOS might change freq behind our back
1479           -> ask driver for current freq and notify governors about a change */
1480         if (cpufreq_driver->get) {
1481                 policy.cur = cpufreq_driver->get(cpu);
1482                 if (!data->cur) {
1483                         dprintk("Driver did not initialize current freq");
1484                         data->cur = policy.cur;
1485                 } else {
1486                         if (data->cur != policy.cur)
1487                                 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1488                 }
1489         }
1490
1491         ret = __cpufreq_set_policy(data, &policy);
1492
1493         mutex_unlock(&data->lock);
1494
1495         cpufreq_cpu_put(data);
1496         return ret;
1497 }
1498 EXPORT_SYMBOL(cpufreq_update_policy);
1499
1500 #ifdef CONFIG_HOTPLUG_CPU
1501 static int cpufreq_cpu_callback(struct notifier_block *nfb,
1502                                         unsigned long action, void *hcpu)
1503 {
1504         unsigned int cpu = (unsigned long)hcpu;
1505         struct cpufreq_policy *policy;
1506         struct sys_device *sys_dev;
1507
1508         sys_dev = get_cpu_sysdev(cpu);
1509
1510         if (sys_dev) {
1511                 switch (action) {
1512                 case CPU_ONLINE:
1513                         cpufreq_add_dev(sys_dev);
1514                         break;
1515                 case CPU_DOWN_PREPARE:
1516                         /*
1517                          * We attempt to put this cpu in lowest frequency
1518                          * possible before going down. This will permit
1519                          * hardware-managed P-State to switch other related
1520                          * threads to min or higher speeds if possible.
1521                          */
1522                         policy = cpufreq_cpu_data[cpu];
1523                         if (policy) {
1524                                 cpufreq_driver_target(policy, policy->min,
1525                                                 CPUFREQ_RELATION_H);
1526                         }
1527                         break;
1528                 case CPU_DEAD:
1529                         cpufreq_remove_dev(sys_dev);
1530                         break;
1531                 }
1532         }
1533         return NOTIFY_OK;
1534 }
1535
1536 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1537 {
1538     .notifier_call = cpufreq_cpu_callback,
1539 };
1540 #endif /* CONFIG_HOTPLUG_CPU */
1541
1542 /*********************************************************************
1543  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1544  *********************************************************************/
1545
1546 /**
1547  * cpufreq_register_driver - register a CPU Frequency driver
1548  * @driver_data: A struct cpufreq_driver containing the values#
1549  * submitted by the CPU Frequency driver.
1550  *
1551  *   Registers a CPU Frequency driver to this core code. This code
1552  * returns zero on success, -EBUSY when another driver got here first
1553  * (and isn't unregistered in the meantime).
1554  *
1555  */
1556 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1557 {
1558         unsigned long flags;
1559         int ret;
1560
1561         if (!driver_data || !driver_data->verify || !driver_data->init ||
1562             ((!driver_data->setpolicy) && (!driver_data->target)))
1563                 return -EINVAL;
1564
1565         dprintk("trying to register driver %s\n", driver_data->name);
1566
1567         if (driver_data->setpolicy)
1568                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1569
1570         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1571         if (cpufreq_driver) {
1572                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1573                 return -EBUSY;
1574         }
1575         cpufreq_driver = driver_data;
1576         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1577
1578         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1579
1580         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1581                 int i;
1582                 ret = -ENODEV;
1583
1584                 /* check for at least one working CPU */
1585                 for (i=0; i<NR_CPUS; i++)
1586                         if (cpufreq_cpu_data[i])
1587                                 ret = 0;
1588
1589                 /* if all ->init() calls failed, unregister */
1590                 if (ret) {
1591                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1592                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1593
1594                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1595                         cpufreq_driver = NULL;
1596                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1597                 }
1598         }
1599
1600         if (!ret) {
1601                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1602                 dprintk("driver %s up and running\n", driver_data->name);
1603                 cpufreq_debug_enable_ratelimit();
1604         }
1605
1606         return (ret);
1607 }
1608 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1609
1610
1611 /**
1612  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1613  *
1614  *    Unregister the current CPUFreq driver. Only call this if you have
1615  * the right to do so, i.e. if you have succeeded in initialising before!
1616  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1617  * currently not initialised.
1618  */
1619 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1620 {
1621         unsigned long flags;
1622
1623         cpufreq_debug_disable_ratelimit();
1624
1625         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1626                 cpufreq_debug_enable_ratelimit();
1627                 return -EINVAL;
1628         }
1629
1630         dprintk("unregistering driver %s\n", driver->name);
1631
1632         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1633         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1634
1635         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1636         cpufreq_driver = NULL;
1637         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1638
1639         return 0;
1640 }
1641 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);