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  *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
   7  *
   8  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
   9  *      Added handling for CPU hotplug
  10  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
  11  *      Fix handling for CPU hotplug -- affected CPUs
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/cpu.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/delay.h>
  23 #include <linux/device.h>
  24 #include <linux/init.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/module.h>
  27 #include <linux/mutex.h>
  28 #include <linux/slab.h>
  29 #include <linux/suspend.h>
  30 #include <linux/tick.h>
  31 #include <trace/events/power.h>
  32
  33 /**
  34  * The "cpufreq driver" - the arch- or hardware-dependent low
  35  * level driver of CPUFreq support, and its spinlock. This lock
  36  * also protects the cpufreq_cpu_data array.
  37  */
  38 static struct cpufreq_driver *cpufreq_driver;
  39 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
  40 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
  41 static DEFINE_RWLOCK(cpufreq_driver_lock);
  42 DEFINE_MUTEX(cpufreq_governor_lock);
  43 static LIST_HEAD(cpufreq_policy_list);
  44
  45 /* This one keeps track of the previously set governor of a removed CPU */
  46 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
  47
  48 /* Flag to suspend/resume CPUFreq governors */
  49 static bool cpufreq_suspended;
  50
  51 static inline bool has_target(void)
  52 {
  53         return cpufreq_driver->target_index || cpufreq_driver->target;
  54 }
  55
  56 /*
  57  * rwsem to guarantee that cpufreq driver module doesn't unload during critical
  58  * sections
  59  */
  60 static DECLARE_RWSEM(cpufreq_rwsem);
  61
  62 /* internal prototypes */
  63 static int __cpufreq_governor(struct cpufreq_policy *policy,
  64                 unsigned int event);
  65 static unsigned int __cpufreq_get(unsigned int cpu);
  66 static void handle_update(struct work_struct *work);
  67
  68 /**
  69  * Two notifier lists: the "policy" list is involved in the
  70  * validation process for a new CPU frequency policy; the
  71  * "transition" list for kernel code that needs to handle
  72  * changes to devices when the CPU clock speed changes.
  73  * The mutex locks both lists.
  74  */
  75 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
  76 static struct srcu_notifier_head cpufreq_transition_notifier_list;
  77
  78 static bool init_cpufreq_transition_notifier_list_called;
  79 static int __init init_cpufreq_transition_notifier_list(void)
  80 {
  81         srcu_init_notifier_head(&cpufreq_transition_notifier_list);
  82         init_cpufreq_transition_notifier_list_called = true;
  83         return 0;
  84 }
  85 pure_initcall(init_cpufreq_transition_notifier_list);
  86
  87 static int off __read_mostly;
  88 static int cpufreq_disabled(void)
  89 {
  90         return off;
  91 }
  92 void disable_cpufreq(void)
  93 {
  94         off = 1;
  95 }
  96 static LIST_HEAD(cpufreq_governor_list);
  97 static DEFINE_MUTEX(cpufreq_governor_mutex);
  98
  99 bool have_governor_per_policy(void)
 100 {
 101         return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
 102 }
 103 EXPORT_SYMBOL_GPL(have_governor_per_policy);
 104
 105 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
 106 {
 107         if (have_governor_per_policy())
 108                 return &policy->kobj;
 109         else
 110                 return cpufreq_global_kobject;
 111 }
 112 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
 113
 114 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
 115 {
 116         u64 idle_time;
 117         u64 cur_wall_time;
 118         u64 busy_time;
 119
 120         cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
 121
 122         busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
 123         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
 124         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
 125         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
 126         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
 127         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
 128
 129         idle_time = cur_wall_time - busy_time;
 130         if (wall)
 131                 *wall = cputime_to_usecs(cur_wall_time);
 132
 133         return cputime_to_usecs(idle_time);
 134 }
 135
 136 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
 137 {
 138         u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
 139
 140         if (idle_time == -1ULL)
 141                 return get_cpu_idle_time_jiffy(cpu, wall);
 142         else if (!io_busy)
 143                 idle_time += get_cpu_iowait_time_us(cpu, wall);
 144
 145         return idle_time;
 146 }
 147 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
 148
 149 /*
 150  * This is a generic cpufreq init() routine which can be used by cpufreq
 151  * drivers of SMP systems. It will do following:
 152  * - validate & show freq table passed
 153  * - set policies transition latency
 154  * - policy->cpus with all possible CPUs
 155  */
 156 int cpufreq_generic_init(struct cpufreq_policy *policy,
 157                 struct cpufreq_frequency_table *table,
 158                 unsigned int transition_latency)
 159 {
 160         int ret;
 161
 162         ret = cpufreq_table_validate_and_show(policy, table);
 163         if (ret) {
 164                 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
 165                 return ret;
 166         }
 167
 168         policy->cpuinfo.transition_latency = transition_latency;
 169
 170         /*
 171          * The driver only supports the SMP configuartion where all processors
 172          * share the clock and voltage and clock.
 173          */
 174         cpumask_setall(policy->cpus);
 175
 176         return 0;
 177 }
 178 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
 179
 180 unsigned int cpufreq_generic_get(unsigned int cpu)
 181 {
 182         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
 183
 184         if (!policy || IS_ERR(policy->clk)) {
 185                 pr_err("%s: No %s associated to cpu: %d\n",
 186                        __func__, policy ? "clk" : "policy", cpu);
 187                 return 0;
 188         }
 189
 190         return clk_get_rate(policy->clk) / 1000;
 191 }
 192 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
 193
 194 /* Only for cpufreq core internal use */
 195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
 196 {
 197         return per_cpu(cpufreq_cpu_data, cpu);
 198 }
 199
 200 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 201 {
 202         struct cpufreq_policy *policy = NULL;
 203         unsigned long flags;
 204
 205         if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
 206                 return NULL;
 207
 208         if (!down_read_trylock(&cpufreq_rwsem))
 209                 return NULL;
 210
 211         /* get the cpufreq driver */
 212         read_lock_irqsave(&cpufreq_driver_lock, flags);
 213
 214         if (cpufreq_driver) {
 215                 /* get the CPU */
 216                 policy = per_cpu(cpufreq_cpu_data, cpu);
 217                 if (policy)
 218                         kobject_get(&policy->kobj);
 219         }
 220
 221         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
 222
 223         if (!policy)
 224                 up_read(&cpufreq_rwsem);
 225
 226         return policy;
 227 }
 228 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
 229
 230 void cpufreq_cpu_put(struct cpufreq_policy *policy)
 231 {
 232         if (cpufreq_disabled())
 233                 return;
 234
 235         kobject_put(&policy->kobj);
 236         up_read(&cpufreq_rwsem);
 237 }
 238 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 239
 240 /*********************************************************************
 241  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 242  *********************************************************************/
 243
 244 /**
 245  * adjust_jiffies - adjust the system "loops_per_jiffy"
 246  *
 247  * This function alters the system "loops_per_jiffy" for the clock
 248  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 249  * systems as each CPU might be scaled differently. So, use the arch
 250  * per-CPU loops_per_jiffy value wherever possible.
 251  */
 252 #ifndef CONFIG_SMP
 253 static unsigned long l_p_j_ref;
 254 static unsigned int l_p_j_ref_freq;
 255
 256 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 257 {
 258         if (ci->flags & CPUFREQ_CONST_LOOPS)
 259                 return;
 260
 261         if (!l_p_j_ref_freq) {
 262                 l_p_j_ref = loops_per_jiffy;
 263                 l_p_j_ref_freq = ci->old;
 264                 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
 265                          l_p_j_ref, l_p_j_ref_freq);
 266         }
 267         if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
 268                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
 269                                                                 ci->new);
 270                 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
 271                          loops_per_jiffy, ci->new);
 272         }
 273 }
 274 #else
 275 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 276 {
 277         return;
 278 }
 279 #endif
 280
 281 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 282                 struct cpufreq_freqs *freqs, unsigned int state)
 283 {
 284         BUG_ON(irqs_disabled());
 285
 286         if (cpufreq_disabled())
 287                 return;
 288
 289         freqs->flags = cpufreq_driver->flags;
 290         pr_debug("notification %u of frequency transition to %u kHz\n",
 291                  state, freqs->new);
 292
 293         switch (state) {
 294
 295         case CPUFREQ_PRECHANGE:
 296                 /* detect if the driver reported a value as "old frequency"
 297                  * which is not equal to what the cpufreq core thinks is
 298                  * "old frequency".
 299                  */
 300                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 301                         if ((policy) && (policy->cpu == freqs->cpu) &&
 302                             (policy->cur) && (policy->cur != freqs->old)) {
 303                                 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
 304                                          freqs->old, policy->cur);
 305                                 freqs->old = policy->cur;
 306                         }
 307                 }
 308                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 309                                 CPUFREQ_PRECHANGE, freqs);
 310                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 311                 break;
 312
 313         case CPUFREQ_POSTCHANGE:
 314                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 315                 pr_debug("FREQ: %lu - CPU: %lu\n",
 316                          (unsigned long)freqs->new, (unsigned long)freqs->cpu);
 317                 trace_cpu_frequency(freqs->new, freqs->cpu);
 318                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 319                                 CPUFREQ_POSTCHANGE, freqs);
 320                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
 321                         policy->cur = freqs->new;
 322                 break;
 323         }
 324 }
 325
 326 /**
 327  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
 328  * on frequency transition.
 329  *
 330  * This function calls the transition notifiers and the "adjust_jiffies"
 331  * function. It is called twice on all CPU frequency changes that have
 332  * external effects.
 333  */
 334 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
 335                 struct cpufreq_freqs *freqs, unsigned int state)
 336 {
 337         for_each_cpu(freqs->cpu, policy->cpus)
 338                 __cpufreq_notify_transition(policy, freqs, state);
 339 }
 340
 341 /* Do post notifications when there are chances that transition has failed */
 342 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
 343                 struct cpufreq_freqs *freqs, int transition_failed)
 344 {
 345         cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
 346         if (!transition_failed)
 347                 return;
 348
 349         swap(freqs->old, freqs->new);
 350         cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
 351         cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
 352 }
 353
 354 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
 355                 struct cpufreq_freqs *freqs)
 356 {
 357
 358         /*
 359          * Catch double invocations of _begin() which lead to self-deadlock.
 360          * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
 361          * doesn't invoke _begin() on their behalf, and hence the chances of
 362          * double invocations are very low. Moreover, there are scenarios
 363          * where these checks can emit false-positive warnings in these
 364          * drivers; so we avoid that by skipping them altogether.
 365          */
 366         WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
 367                                 && current == policy->transition_task);
 368
 369 wait:
 370         wait_event(policy->transition_wait, !policy->transition_ongoing);
 371
 372         spin_lock(&policy->transition_lock);
 373
 374         if (unlikely(policy->transition_ongoing)) {
 375                 spin_unlock(&policy->transition_lock);
 376                 goto wait;
 377         }
 378
 379         policy->transition_ongoing = true;
 380         policy->transition_task = current;
 381
 382         spin_unlock(&policy->transition_lock);
 383
 384         cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
 385 }
 386 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
 387
 388 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
 389                 struct cpufreq_freqs *freqs, int transition_failed)
 390 {
 391         if (unlikely(WARN_ON(!policy->transition_ongoing)))
 392                 return;
 393
 394         cpufreq_notify_post_transition(policy, freqs, transition_failed);
 395
 396         policy->transition_ongoing = false;
 397         policy->transition_task = NULL;
 398
 399         wake_up(&policy->transition_wait);
 400 }
 401 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
 402
 403
 404 /*********************************************************************
 405  *                          SYSFS INTERFACE                          *
 406  *********************************************************************/
 407 static ssize_t show_boost(struct kobject *kobj,
 408                                  struct attribute *attr, char *buf)
 409 {
 410         return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
 411 }
 412
 413 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
 414                                   const char *buf, size_t count)
 415 {
 416         int ret, enable;
 417
 418         ret = sscanf(buf, "%d", &enable);
 419         if (ret != 1 || enable < 0 || enable > 1)
 420                 return -EINVAL;
 421
 422         if (cpufreq_boost_trigger_state(enable)) {
 423                 pr_err("%s: Cannot %s BOOST!\n",
 424                        __func__, enable ? "enable" : "disable");
 425                 return -EINVAL;
 426         }
 427
 428         pr_debug("%s: cpufreq BOOST %s\n",
 429                  __func__, enable ? "enabled" : "disabled");
 430
 431         return count;
 432 }
 433 define_one_global_rw(boost);
 434
 435 static struct cpufreq_governor *__find_governor(const char *str_governor)
 436 {
 437         struct cpufreq_governor *t;
 438
 439         list_for_each_entry(t, &cpufreq_governor_list, governor_list)
 440                 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
 441                         return t;
 442
 443         return NULL;
 444 }
 445
 446 /**
 447  * cpufreq_parse_governor - parse a governor string
 448  */
 449 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
 450                                 struct cpufreq_governor **governor)
 451 {
 452         int err = -EINVAL;
 453
 454         if (!cpufreq_driver)
 455                 goto out;
 456
 457         if (cpufreq_driver->setpolicy) {
 458                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
 459                         *policy = CPUFREQ_POLICY_PERFORMANCE;
 460                         err = 0;
 461                 } else if (!strnicmp(str_governor, "powersave",
 462                                                 CPUFREQ_NAME_LEN)) {
 463                         *policy = CPUFREQ_POLICY_POWERSAVE;
 464                         err = 0;
 465                 }
 466         } else if (has_target()) {
 467                 struct cpufreq_governor *t;
 468
 469                 mutex_lock(&cpufreq_governor_mutex);
 470
 471                 t = __find_governor(str_governor);
 472
 473                 if (t == NULL) {
 474                         int ret;
 475
 476                         mutex_unlock(&cpufreq_governor_mutex);
 477                         ret = request_module("cpufreq_%s", str_governor);
 478                         mutex_lock(&cpufreq_governor_mutex);
 479
 480                         if (ret == 0)
 481                                 t = __find_governor(str_governor);
 482                 }
 483
 484                 if (t != NULL) {
 485                         *governor = t;
 486                         err = 0;
 487                 }
 488
 489                 mutex_unlock(&cpufreq_governor_mutex);
 490         }
 491 out:
 492         return err;
 493 }
 494
 495 /**
 496  * cpufreq_per_cpu_attr_read() / show_##file_name() -
 497  * print out cpufreq information
 498  *
 499  * Write out information from cpufreq_driver->policy[cpu]; object must be
 500  * "unsigned int".
 501  */
 502
 503 #define show_one(file_name, object)                     \
 504 static ssize_t show_##file_name                         \
 505 (struct cpufreq_policy *policy, char *buf)              \
 506 {                                                       \
 507         return sprintf(buf, "%u\n", policy->object);    \
 508 }
 509
 510 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 511 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 512 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
 513 show_one(scaling_min_freq, min);
 514 show_one(scaling_max_freq, max);
 515 show_one(scaling_cur_freq, cur);
 516
 517 static int cpufreq_set_policy(struct cpufreq_policy *policy,
 518                                 struct cpufreq_policy *new_policy);
 519
 520 /**
 521  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 522  */
 523 #define store_one(file_name, object)                    \
 524 static ssize_t store_##file_name                                        \
 525 (struct cpufreq_policy *policy, const char *buf, size_t count)          \
 526 {                                                                       \
 527         int ret;                                                        \
 528         struct cpufreq_policy new_policy;                               \
 529                                                                         \
 530         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
 531         if (ret)                                                        \
 532                 return -EINVAL;                                         \
 533                                                                         \
 534         ret = sscanf(buf, "%u", &new_policy.object);                    \
 535         if (ret != 1)                                                   \
 536                 return -EINVAL;                                         \
 537                                                                         \
 538         ret = cpufreq_set_policy(policy, &new_policy);          \
 539         policy->user_policy.object = policy->object;                    \
 540                                                                         \
 541         return ret ? ret : count;                                       \
 542 }
 543
 544 store_one(scaling_min_freq, min);
 545 store_one(scaling_max_freq, max);
 546
 547 /**
 548  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 549  */
 550 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
 551                                         char *buf)
 552 {
 553         unsigned int cur_freq = __cpufreq_get(policy->cpu);
 554         if (!cur_freq)
 555                 return sprintf(buf, "<unknown>");
 556         return sprintf(buf, "%u\n", cur_freq);
 557 }
 558
 559 /**
 560  * show_scaling_governor - show the current policy for the specified CPU
 561  */
 562 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 563 {
 564         if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
 565                 return sprintf(buf, "powersave\n");
 566         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 567                 return sprintf(buf, "performance\n");
 568         else if (policy->governor)
 569                 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
 570                                 policy->governor->name);
 571         return -EINVAL;
 572 }
 573
 574 /**
 575  * store_scaling_governor - store policy for the specified CPU
 576  */
 577 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 578                                         const char *buf, size_t count)
 579 {
 580         int ret;
 581         char    str_governor[16];
 582         struct cpufreq_policy new_policy;
 583
 584         ret = cpufreq_get_policy(&new_policy, policy->cpu);
 585         if (ret)
 586                 return ret;
 587
 588         ret = sscanf(buf, "%15s", str_governor);
 589         if (ret != 1)
 590                 return -EINVAL;
 591
 592         if (cpufreq_parse_governor(str_governor, &new_policy.policy,
 593                                                 &new_policy.governor))
 594                 return -EINVAL;
 595
 596         ret = cpufreq_set_policy(policy, &new_policy);
 597
 598         policy->user_policy.policy = policy->policy;
 599         policy->user_policy.governor = policy->governor;
 600
 601         if (ret)
 602                 return ret;
 603         else
 604                 return count;
 605 }
 606
 607 /**
 608  * show_scaling_driver - show the cpufreq driver currently loaded
 609  */
 610 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
 611 {
 612         return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
 613 }
 614
 615 /**
 616  * show_scaling_available_governors - show the available CPUfreq governors
 617  */
 618 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
 619                                                 char *buf)
 620 {
 621         ssize_t i = 0;
 622         struct cpufreq_governor *t;
 623
 624         if (!has_target()) {
 625                 i += sprintf(buf, "performance powersave");
 626                 goto out;
 627         }
 628
 629         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 630                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
 631                     - (CPUFREQ_NAME_LEN + 2)))
 632                         goto out;
 633                 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
 634         }
 635 out:
 636         i += sprintf(&buf[i], "\n");
 637         return i;
 638 }
 639
 640 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
 641 {
 642         ssize_t i = 0;
 643         unsigned int cpu;
 644
 645         for_each_cpu(cpu, mask) {
 646                 if (i)
 647                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 648                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 649                 if (i >= (PAGE_SIZE - 5))
 650                         break;
 651         }
 652         i += sprintf(&buf[i], "\n");
 653         return i;
 654 }
 655 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
 656
 657 /**
 658  * show_related_cpus - show the CPUs affected by each transition even if
 659  * hw coordination is in use
 660  */
 661 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
 662 {
 663         return cpufreq_show_cpus(policy->related_cpus, buf);
 664 }
 665
 666 /**
 667  * show_affected_cpus - show the CPUs affected by each transition
 668  */
 669 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
 670 {
 671         return cpufreq_show_cpus(policy->cpus, buf);
 672 }
 673
 674 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
 675                                         const char *buf, size_t count)
 676 {
 677         unsigned int freq = 0;
 678         unsigned int ret;
 679
 680         if (!policy->governor || !policy->governor->store_setspeed)
 681                 return -EINVAL;
 682
 683         ret = sscanf(buf, "%u", &freq);
 684         if (ret != 1)
 685                 return -EINVAL;
 686
 687         policy->governor->store_setspeed(policy, freq);
 688
 689         return count;
 690 }
 691
 692 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
 693 {
 694         if (!policy->governor || !policy->governor->show_setspeed)
 695                 return sprintf(buf, "<unsupported>\n");
 696
 697         return policy->governor->show_setspeed(policy, buf);
 698 }
 699
 700 /**
 701  * show_bios_limit - show the current cpufreq HW/BIOS limitation
 702  */
 703 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
 704 {
 705         unsigned int limit;
 706         int ret;
 707         if (cpufreq_driver->bios_limit) {
 708                 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
 709                 if (!ret)
 710                         return sprintf(buf, "%u\n", limit);
 711         }
 712         return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
 713 }
 714
 715 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
 716 cpufreq_freq_attr_ro(cpuinfo_min_freq);
 717 cpufreq_freq_attr_ro(cpuinfo_max_freq);
 718 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
 719 cpufreq_freq_attr_ro(scaling_available_governors);
 720 cpufreq_freq_attr_ro(scaling_driver);
 721 cpufreq_freq_attr_ro(scaling_cur_freq);
 722 cpufreq_freq_attr_ro(bios_limit);
 723 cpufreq_freq_attr_ro(related_cpus);
 724 cpufreq_freq_attr_ro(affected_cpus);
 725 cpufreq_freq_attr_rw(scaling_min_freq);
 726 cpufreq_freq_attr_rw(scaling_max_freq);
 727 cpufreq_freq_attr_rw(scaling_governor);
 728 cpufreq_freq_attr_rw(scaling_setspeed);
 729
 730 static struct attribute *default_attrs[] = {
 731         &cpuinfo_min_freq.attr,
 732         &cpuinfo_max_freq.attr,
 733         &cpuinfo_transition_latency.attr,
 734         &scaling_min_freq.attr,
 735         &scaling_max_freq.attr,
 736         &affected_cpus.attr,
 737         &related_cpus.attr,
 738         &scaling_governor.attr,
 739         &scaling_driver.attr,
 740         &scaling_available_governors.attr,
 741         &scaling_setspeed.attr,
 742         NULL
 743 };
 744
 745 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 746 #define to_attr(a) container_of(a, struct freq_attr, attr)
 747
 748 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 749 {
 750         struct cpufreq_policy *policy = to_policy(kobj);
 751         struct freq_attr *fattr = to_attr(attr);
 752         ssize_t ret;
 753
 754         if (!down_read_trylock(&cpufreq_rwsem))
 755                 return -EINVAL;
 756
 757         down_read(&policy->rwsem);
 758
 759         if (fattr->show)
 760                 ret = fattr->show(policy, buf);
 761         else
 762                 ret = -EIO;
 763
 764         up_read(&policy->rwsem);
 765         up_read(&cpufreq_rwsem);
 766
 767         return ret;
 768 }
 769
 770 static ssize_t store(struct kobject *kobj, struct attribute *attr,
 771                      const char *buf, size_t count)
 772 {
 773         struct cpufreq_policy *policy = to_policy(kobj);
 774         struct freq_attr *fattr = to_attr(attr);
 775         ssize_t ret = -EINVAL;
 776
 777         get_online_cpus();
 778
 779         if (!cpu_online(policy->cpu))
 780                 goto unlock;
 781
 782         if (!down_read_trylock(&cpufreq_rwsem))
 783                 goto unlock;
 784
 785         down_write(&policy->rwsem);
 786
 787         if (fattr->store)
 788                 ret = fattr->store(policy, buf, count);
 789         else
 790                 ret = -EIO;
 791
 792         up_write(&policy->rwsem);
 793
 794         up_read(&cpufreq_rwsem);
 795 unlock:
 796         put_online_cpus();
 797
 798         return ret;
 799 }
 800
 801 static void cpufreq_sysfs_release(struct kobject *kobj)
 802 {
 803         struct cpufreq_policy *policy = to_policy(kobj);
 804         pr_debug("last reference is dropped\n");
 805         complete(&policy->kobj_unregister);
 806 }
 807
 808 static const struct sysfs_ops sysfs_ops = {
 809         .show   = show,
 810         .store  = store,
 811 };
 812
 813 static struct kobj_type ktype_cpufreq = {
 814         .sysfs_ops      = &sysfs_ops,
 815         .default_attrs  = default_attrs,
 816         .release        = cpufreq_sysfs_release,
 817 };
 818
 819 struct kobject *cpufreq_global_kobject;
 820 EXPORT_SYMBOL(cpufreq_global_kobject);
 821
 822 static int cpufreq_global_kobject_usage;
 823
 824 int cpufreq_get_global_kobject(void)
 825 {
 826         if (!cpufreq_global_kobject_usage++)
 827                 return kobject_add(cpufreq_global_kobject,
 828                                 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
 829
 830         return 0;
 831 }
 832 EXPORT_SYMBOL(cpufreq_get_global_kobject);
 833
 834 void cpufreq_put_global_kobject(void)
 835 {
 836         if (!--cpufreq_global_kobject_usage)
 837                 kobject_del(cpufreq_global_kobject);
 838 }
 839 EXPORT_SYMBOL(cpufreq_put_global_kobject);
 840
 841 int cpufreq_sysfs_create_file(const struct attribute *attr)
 842 {
 843         int ret = cpufreq_get_global_kobject();
 844
 845         if (!ret) {
 846                 ret = sysfs_create_file(cpufreq_global_kobject, attr);
 847                 if (ret)
 848                         cpufreq_put_global_kobject();
 849         }
 850
 851         return ret;
 852 }
 853 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
 854
 855 void cpufreq_sysfs_remove_file(const struct attribute *attr)
 856 {
 857         sysfs_remove_file(cpufreq_global_kobject, attr);
 858         cpufreq_put_global_kobject();
 859 }
 860 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
 861
 862 /* symlink affected CPUs */
 863 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
 864 {
 865         unsigned int j;
 866         int ret = 0;
 867
 868         for_each_cpu(j, policy->cpus) {
 869                 struct device *cpu_dev;
 870
 871                 if (j == policy->cpu)
 872                         continue;
 873
 874                 pr_debug("Adding link for CPU: %u\n", j);
 875                 cpu_dev = get_cpu_device(j);
 876                 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
 877                                         "cpufreq");
 878                 if (ret)
 879                         break;
 880         }
 881         return ret;
 882 }
 883
 884 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
 885                                      struct device *dev)
 886 {
 887         struct freq_attr **drv_attr;
 888         int ret = 0;
 889
 890         /* prepare interface data */
 891         ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
 892                                    &dev->kobj, "cpufreq");
 893         if (ret)
 894                 return ret;
 895
 896         /* set up files for this cpu device */
 897         drv_attr = cpufreq_driver->attr;
 898         while ((drv_attr) && (*drv_attr)) {
 899                 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 900                 if (ret)
 901                         goto err_out_kobj_put;
 902                 drv_attr++;
 903         }
 904         if (cpufreq_driver->get) {
 905                 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
 906                 if (ret)
 907                         goto err_out_kobj_put;
 908         }
 909         if (has_target()) {
 910                 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 911                 if (ret)
 912                         goto err_out_kobj_put;
 913         }
 914         if (cpufreq_driver->bios_limit) {
 915                 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
 916                 if (ret)
 917                         goto err_out_kobj_put;
 918         }
 919
 920         ret = cpufreq_add_dev_symlink(policy);
 921         if (ret)
 922                 goto err_out_kobj_put;
 923
 924         return ret;
 925
 926 err_out_kobj_put:
 927         kobject_put(&policy->kobj);
 928         wait_for_completion(&policy->kobj_unregister);
 929         return ret;
 930 }
 931
 932 static void cpufreq_init_policy(struct cpufreq_policy *policy)
 933 {
 934         struct cpufreq_governor *gov = NULL;
 935         struct cpufreq_policy new_policy;
 936         int ret = 0;
 937
 938         memcpy(&new_policy, policy, sizeof(*policy));
 939
 940         /* Update governor of new_policy to the governor used before hotplug */
 941         gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
 942         if (gov)
 943                 pr_debug("Restoring governor %s for cpu %d\n",
 944                                 policy->governor->name, policy->cpu);
 945         else
 946                 gov = CPUFREQ_DEFAULT_GOVERNOR;
 947
 948         new_policy.governor = gov;
 949
 950         /* Use the default policy if its valid. */
 951         if (cpufreq_driver->setpolicy)
 952                 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
 953
 954         /* set default policy */
 955         ret = cpufreq_set_policy(policy, &new_policy);
 956         if (ret) {
 957                 pr_debug("setting policy failed\n");
 958                 if (cpufreq_driver->exit)
 959                         cpufreq_driver->exit(policy);
 960         }
 961 }
 962
 963 #ifdef CONFIG_HOTPLUG_CPU
 964 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
 965                                   unsigned int cpu, struct device *dev)
 966 {
 967         int ret = 0;
 968         unsigned long flags;
 969
 970         if (has_target()) {
 971                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
 972                 if (ret) {
 973                         pr_err("%s: Failed to stop governor\n", __func__);
 974                         return ret;
 975                 }
 976         }
 977
 978         down_write(&policy->rwsem);
 979
 980         write_lock_irqsave(&cpufreq_driver_lock, flags);
 981
 982         cpumask_set_cpu(cpu, policy->cpus);
 983         per_cpu(cpufreq_cpu_data, cpu) = policy;
 984         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 985
 986         up_write(&policy->rwsem);
 987
 988         if (has_target()) {
 989                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
 990                 if (!ret)
 991                         ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
 992
 993                 if (ret) {
 994                         pr_err("%s: Failed to start governor\n", __func__);
 995                         return ret;
 996                 }
 997         }
 998
 999         return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
1000 }
1001 #endif
1002
1003 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
1004 {
1005         struct cpufreq_policy *policy;
1006         unsigned long flags;
1007
1008         read_lock_irqsave(&cpufreq_driver_lock, flags);
1009
1010         policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
1011
1012         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1013
1014         policy->governor = NULL;
1015
1016         return policy;
1017 }
1018
1019 static struct cpufreq_policy *cpufreq_policy_alloc(void)
1020 {
1021         struct cpufreq_policy *policy;
1022
1023         policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1024         if (!policy)
1025                 return NULL;
1026
1027         if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1028                 goto err_free_policy;
1029
1030         if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1031                 goto err_free_cpumask;
1032
1033         INIT_LIST_HEAD(&policy->policy_list);
1034         init_rwsem(&policy->rwsem);
1035         spin_lock_init(&policy->transition_lock);
1036         init_waitqueue_head(&policy->transition_wait);
1037
1038         return policy;
1039
1040 err_free_cpumask:
1041         free_cpumask_var(policy->cpus);
1042 err_free_policy:
1043         kfree(policy);
1044
1045         return NULL;
1046 }
1047
1048 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1049 {
1050         struct kobject *kobj;
1051         struct completion *cmp;
1052
1053         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1054                         CPUFREQ_REMOVE_POLICY, policy);
1055
1056         down_read(&policy->rwsem);
1057         kobj = &policy->kobj;
1058         cmp = &policy->kobj_unregister;
1059         up_read(&policy->rwsem);
1060         kobject_put(kobj);
1061
1062         /*
1063          * We need to make sure that the underlying kobj is
1064          * actually not referenced anymore by anybody before we
1065          * proceed with unloading.
1066          */
1067         pr_debug("waiting for dropping of refcount\n");
1068         wait_for_completion(cmp);
1069         pr_debug("wait complete\n");
1070 }
1071
1072 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1073 {
1074         free_cpumask_var(policy->related_cpus);
1075         free_cpumask_var(policy->cpus);
1076         kfree(policy);
1077 }
1078
1079 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1080 {
1081         if (WARN_ON(cpu == policy->cpu))
1082                 return;
1083
1084         down_write(&policy->rwsem);
1085
1086         policy->last_cpu = policy->cpu;
1087         policy->cpu = cpu;
1088
1089         up_write(&policy->rwsem);
1090
1091         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1092                         CPUFREQ_UPDATE_POLICY_CPU, policy);
1093 }
1094
1095 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1096 {
1097         unsigned int j, cpu = dev->id;
1098         int ret = -ENOMEM;
1099         struct cpufreq_policy *policy;
1100         unsigned long flags;
1101         bool recover_policy = cpufreq_suspended;
1102 #ifdef CONFIG_HOTPLUG_CPU
1103         struct cpufreq_policy *tpolicy;
1104 #endif
1105
1106         if (cpu_is_offline(cpu))
1107                 return 0;
1108
1109         pr_debug("adding CPU %u\n", cpu);
1110
1111 #ifdef CONFIG_SMP
1112         /* check whether a different CPU already registered this
1113          * CPU because it is in the same boat. */
1114         policy = cpufreq_cpu_get(cpu);
1115         if (unlikely(policy)) {
1116                 cpufreq_cpu_put(policy);
1117                 return 0;
1118         }
1119 #endif
1120
1121         if (!down_read_trylock(&cpufreq_rwsem))
1122                 return 0;
1123
1124 #ifdef CONFIG_HOTPLUG_CPU
1125         /* Check if this cpu was hot-unplugged earlier and has siblings */
1126         read_lock_irqsave(&cpufreq_driver_lock, flags);
1127         list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1128                 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1129                         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1130                         ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1131                         up_read(&cpufreq_rwsem);
1132                         return ret;
1133                 }
1134         }
1135         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1136 #endif
1137
1138         /*
1139          * Restore the saved policy when doing light-weight init and fall back
1140          * to the full init if that fails.
1141          */
1142         policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1143         if (!policy) {
1144                 recover_policy = false;
1145                 policy = cpufreq_policy_alloc();
1146                 if (!policy)
1147                         goto nomem_out;
1148         }
1149
1150         /*
1151          * In the resume path, since we restore a saved policy, the assignment
1152          * to policy->cpu is like an update of the existing policy, rather than
1153          * the creation of a brand new one. So we need to perform this update
1154          * by invoking update_policy_cpu().
1155          */
1156         if (recover_policy && cpu != policy->cpu) {
1157                 update_policy_cpu(policy, cpu);
1158                 WARN_ON(kobject_move(&policy->kobj, &dev->kobj));
1159         } else {
1160                 policy->cpu = cpu;
1161         }
1162
1163         cpumask_copy(policy->cpus, cpumask_of(cpu));
1164
1165         init_completion(&policy->kobj_unregister);
1166         INIT_WORK(&policy->update, handle_update);
1167
1168         /* call driver. From then on the cpufreq must be able
1169          * to accept all calls to ->verify and ->setpolicy for this CPU
1170          */
1171         ret = cpufreq_driver->init(policy);
1172         if (ret) {
1173                 pr_debug("initialization failed\n");
1174                 goto err_set_policy_cpu;
1175         }
1176
1177         /* related cpus should atleast have policy->cpus */
1178         cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1179
1180         /*
1181          * affected cpus must always be the one, which are online. We aren't
1182          * managing offline cpus here.
1183          */
1184         cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1185
1186         if (!recover_policy) {
1187                 policy->user_policy.min = policy->min;
1188                 policy->user_policy.max = policy->max;
1189         }
1190
1191         down_write(&policy->rwsem);
1192         write_lock_irqsave(&cpufreq_driver_lock, flags);
1193         for_each_cpu(j, policy->cpus)
1194                 per_cpu(cpufreq_cpu_data, j) = policy;
1195         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1196
1197         if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1198                 policy->cur = cpufreq_driver->get(policy->cpu);
1199                 if (!policy->cur) {
1200                         pr_err("%s: ->get() failed\n", __func__);
1201                         goto err_get_freq;
1202                 }
1203         }
1204
1205         /*
1206          * Sometimes boot loaders set CPU frequency to a value outside of
1207          * frequency table present with cpufreq core. In such cases CPU might be
1208          * unstable if it has to run on that frequency for long duration of time
1209          * and so its better to set it to a frequency which is specified in
1210          * freq-table. This also makes cpufreq stats inconsistent as
1211          * cpufreq-stats would fail to register because current frequency of CPU
1212          * isn't found in freq-table.
1213          *
1214          * Because we don't want this change to effect boot process badly, we go
1215          * for the next freq which is >= policy->cur ('cur' must be set by now,
1216          * otherwise we will end up setting freq to lowest of the table as 'cur'
1217          * is initialized to zero).
1218          *
1219          * We are passing target-freq as "policy->cur - 1" otherwise
1220          * __cpufreq_driver_target() would simply fail, as policy->cur will be
1221          * equal to target-freq.
1222          */
1223         if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1224             && has_target()) {
1225                 /* Are we running at unknown frequency ? */
1226                 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1227                 if (ret == -EINVAL) {
1228                         /* Warn user and fix it */
1229                         pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1230                                 __func__, policy->cpu, policy->cur);
1231                         ret = __cpufreq_driver_target(policy, policy->cur - 1,
1232                                 CPUFREQ_RELATION_L);
1233
1234                         /*
1235                          * Reaching here after boot in a few seconds may not
1236                          * mean that system will remain stable at "unknown"
1237                          * frequency for longer duration. Hence, a BUG_ON().
1238                          */
1239                         BUG_ON(ret);
1240                         pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1241                                 __func__, policy->cpu, policy->cur);
1242                 }
1243         }
1244
1245         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1246                                      CPUFREQ_START, policy);
1247
1248         if (!recover_policy) {
1249                 ret = cpufreq_add_dev_interface(policy, dev);
1250                 if (ret)
1251                         goto err_out_unregister;
1252                 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1253                                 CPUFREQ_CREATE_POLICY, policy);
1254         }
1255
1256         write_lock_irqsave(&cpufreq_driver_lock, flags);
1257         list_add(&policy->policy_list, &cpufreq_policy_list);
1258         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1259
1260         cpufreq_init_policy(policy);
1261
1262         if (!recover_policy) {
1263                 policy->user_policy.policy = policy->policy;
1264                 policy->user_policy.governor = policy->governor;
1265         }
1266         up_write(&policy->rwsem);
1267
1268         kobject_uevent(&policy->kobj, KOBJ_ADD);
1269         up_read(&cpufreq_rwsem);
1270
1271         pr_debug("initialization complete\n");
1272
1273         return 0;
1274
1275 err_out_unregister:
1276 err_get_freq:
1277         write_lock_irqsave(&cpufreq_driver_lock, flags);
1278         for_each_cpu(j, policy->cpus)
1279                 per_cpu(cpufreq_cpu_data, j) = NULL;
1280         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1281
1282         if (cpufreq_driver->exit)
1283                 cpufreq_driver->exit(policy);
1284 err_set_policy_cpu:
1285         if (recover_policy) {
1286                 /* Do not leave stale fallback data behind. */
1287                 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1288                 cpufreq_policy_put_kobj(policy);
1289         }
1290         cpufreq_policy_free(policy);
1291
1292 nomem_out:
1293         up_read(&cpufreq_rwsem);
1294
1295         return ret;
1296 }
1297
1298 /**
1299  * cpufreq_add_dev - add a CPU device
1300  *
1301  * Adds the cpufreq interface for a CPU device.
1302  *
1303  * The Oracle says: try running cpufreq registration/unregistration concurrently
1304  * with with cpu hotplugging and all hell will break loose. Tried to clean this
1305  * mess up, but more thorough testing is needed. - Mathieu
1306  */
1307 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1308 {
1309         return __cpufreq_add_dev(dev, sif);
1310 }
1311
1312 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
1313                                            unsigned int old_cpu)
1314 {
1315         struct device *cpu_dev;
1316         int ret;
1317
1318         /* first sibling now owns the new sysfs dir */
1319         cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
1320
1321         sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1322         ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1323         if (ret) {
1324                 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1325
1326                 down_write(&policy->rwsem);
1327                 cpumask_set_cpu(old_cpu, policy->cpus);
1328                 up_write(&policy->rwsem);
1329
1330                 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1331                                         "cpufreq");
1332
1333                 return -EINVAL;
1334         }
1335
1336         return cpu_dev->id;
1337 }
1338
1339 static int __cpufreq_remove_dev_prepare(struct device *dev,
1340                                         struct subsys_interface *sif)
1341 {
1342         unsigned int cpu = dev->id, cpus;
1343         int new_cpu, ret;
1344         unsigned long flags;
1345         struct cpufreq_policy *policy;
1346
1347         pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1348
1349         write_lock_irqsave(&cpufreq_driver_lock, flags);
1350
1351         policy = per_cpu(cpufreq_cpu_data, cpu);
1352
1353         /* Save the policy somewhere when doing a light-weight tear-down */
1354         if (cpufreq_suspended)
1355                 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1356
1357         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1358
1359         if (!policy) {
1360                 pr_debug("%s: No cpu_data found\n", __func__);
1361                 return -EINVAL;
1362         }
1363
1364         if (has_target()) {
1365                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1366                 if (ret) {
1367                         pr_err("%s: Failed to stop governor\n", __func__);
1368                         return ret;
1369                 }
1370         }
1371
1372         if (!cpufreq_driver->setpolicy)
1373                 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1374                         policy->governor->name, CPUFREQ_NAME_LEN);
1375
1376         down_read(&policy->rwsem);
1377         cpus = cpumask_weight(policy->cpus);
1378         up_read(&policy->rwsem);
1379
1380         if (cpu != policy->cpu) {
1381                 sysfs_remove_link(&dev->kobj, "cpufreq");
1382         } else if (cpus > 1) {
1383                 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
1384                 if (new_cpu >= 0) {
1385                         update_policy_cpu(policy, new_cpu);
1386
1387                         if (!cpufreq_suspended)
1388                                 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1389                                          __func__, new_cpu, cpu);
1390                 }
1391         } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
1392                 cpufreq_driver->stop_cpu(policy);
1393         }
1394
1395         return 0;
1396 }
1397
1398 static int __cpufreq_remove_dev_finish(struct device *dev,
1399                                        struct subsys_interface *sif)
1400 {
1401         unsigned int cpu = dev->id, cpus;
1402         int ret;
1403         unsigned long flags;
1404         struct cpufreq_policy *policy;
1405
1406         read_lock_irqsave(&cpufreq_driver_lock, flags);
1407         policy = per_cpu(cpufreq_cpu_data, cpu);
1408         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1409
1410         if (!policy) {
1411                 pr_debug("%s: No cpu_data found\n", __func__);
1412                 return -EINVAL;
1413         }
1414
1415         down_write(&policy->rwsem);
1416         cpus = cpumask_weight(policy->cpus);
1417
1418         if (cpus > 1)
1419                 cpumask_clear_cpu(cpu, policy->cpus);
1420         up_write(&policy->rwsem);
1421
1422         /* If cpu is last user of policy, free policy */
1423         if (cpus == 1) {
1424                 if (has_target()) {
1425                         ret = __cpufreq_governor(policy,
1426                                         CPUFREQ_GOV_POLICY_EXIT);
1427                         if (ret) {
1428                                 pr_err("%s: Failed to exit governor\n",
1429                                        __func__);
1430                                 return ret;
1431                         }
1432                 }
1433
1434                 if (!cpufreq_suspended)
1435                         cpufreq_policy_put_kobj(policy);
1436
1437                 /*
1438                  * Perform the ->exit() even during light-weight tear-down,
1439                  * since this is a core component, and is essential for the
1440                  * subsequent light-weight ->init() to succeed.
1441                  */
1442                 if (cpufreq_driver->exit)
1443                         cpufreq_driver->exit(policy);
1444
1445                 /* Remove policy from list of active policies */
1446                 write_lock_irqsave(&cpufreq_driver_lock, flags);
1447                 list_del(&policy->policy_list);
1448                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1449
1450                 if (!cpufreq_suspended)
1451                         cpufreq_policy_free(policy);
1452         } else if (has_target()) {
1453                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1454                 if (!ret)
1455                         ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1456
1457                 if (ret) {
1458                         pr_err("%s: Failed to start governor\n", __func__);
1459                         return ret;
1460                 }
1461         }
1462
1463         per_cpu(cpufreq_cpu_data, cpu) = NULL;
1464         return 0;
1465 }
1466
1467 /**
1468  * cpufreq_remove_dev - remove a CPU device
1469  *
1470  * Removes the cpufreq interface for a CPU device.
1471  */
1472 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1473 {
1474         unsigned int cpu = dev->id;
1475         int ret;
1476
1477         if (cpu_is_offline(cpu))
1478                 return 0;
1479
1480         ret = __cpufreq_remove_dev_prepare(dev, sif);
1481
1482         if (!ret)
1483                 ret = __cpufreq_remove_dev_finish(dev, sif);
1484
1485         return ret;
1486 }
1487
1488 static void handle_update(struct work_struct *work)
1489 {
1490         struct cpufreq_policy *policy =
1491                 container_of(work, struct cpufreq_policy, update);
1492         unsigned int cpu = policy->cpu;
1493         pr_debug("handle_update for cpu %u called\n", cpu);
1494         cpufreq_update_policy(cpu);
1495 }
1496
1497 /**
1498  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1499  *      in deep trouble.
1500  *      @cpu: cpu number
1501  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
1502  *      @new_freq: CPU frequency the CPU actually runs at
1503  *
1504  *      We adjust to current frequency first, and need to clean up later.
1505  *      So either call to cpufreq_update_policy() or schedule handle_update()).
1506  */
1507 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1508                                 unsigned int new_freq)
1509 {
1510         struct cpufreq_policy *policy;
1511         struct cpufreq_freqs freqs;
1512         unsigned long flags;
1513
1514         pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1515                  old_freq, new_freq);
1516
1517         freqs.old = old_freq;
1518         freqs.new = new_freq;
1519
1520         read_lock_irqsave(&cpufreq_driver_lock, flags);
1521         policy = per_cpu(cpufreq_cpu_data, cpu);
1522         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1523
1524         cpufreq_freq_transition_begin(policy, &freqs);
1525         cpufreq_freq_transition_end(policy, &freqs, 0);
1526 }
1527
1528 /**
1529  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1530  * @cpu: CPU number
1531  *
1532  * This is the last known freq, without actually getting it from the driver.
1533  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1534  */
1535 unsigned int cpufreq_quick_get(unsigned int cpu)
1536 {
1537         struct cpufreq_policy *policy;
1538         unsigned int ret_freq = 0;
1539
1540         if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1541                 return cpufreq_driver->get(cpu);
1542
1543         policy = cpufreq_cpu_get(cpu);
1544         if (policy) {
1545                 ret_freq = policy->cur;
1546                 cpufreq_cpu_put(policy);
1547         }
1548
1549         return ret_freq;
1550 }
1551 EXPORT_SYMBOL(cpufreq_quick_get);
1552
1553 /**
1554  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1555  * @cpu: CPU number
1556  *
1557  * Just return the max possible frequency for a given CPU.
1558  */
1559 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1560 {
1561         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1562         unsigned int ret_freq = 0;
1563
1564         if (policy) {
1565                 ret_freq = policy->max;
1566                 cpufreq_cpu_put(policy);
1567         }
1568
1569         return ret_freq;
1570 }
1571 EXPORT_SYMBOL(cpufreq_quick_get_max);
1572
1573 static unsigned int __cpufreq_get(unsigned int cpu)
1574 {
1575         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1576         unsigned int ret_freq = 0;
1577
1578         if (!cpufreq_driver->get)
1579                 return ret_freq;
1580
1581         ret_freq = cpufreq_driver->get(cpu);
1582
1583         if (ret_freq && policy->cur &&
1584                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1585                 /* verify no discrepancy between actual and
1586                                         saved value exists */
1587                 if (unlikely(ret_freq != policy->cur)) {
1588                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1589                         schedule_work(&policy->update);
1590                 }
1591         }
1592
1593         return ret_freq;
1594 }
1595
1596 /**
1597  * cpufreq_get - get the current CPU frequency (in kHz)
1598  * @cpu: CPU number
1599  *
1600  * Get the CPU current (static) CPU frequency
1601  */
1602 unsigned int cpufreq_get(unsigned int cpu)
1603 {
1604         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1605         unsigned int ret_freq = 0;
1606
1607         if (policy) {
1608                 down_read(&policy->rwsem);
1609                 ret_freq = __cpufreq_get(cpu);
1610                 up_read(&policy->rwsem);
1611
1612                 cpufreq_cpu_put(policy);
1613         }
1614
1615         return ret_freq;
1616 }
1617 EXPORT_SYMBOL(cpufreq_get);
1618
1619 static struct subsys_interface cpufreq_interface = {
1620         .name           = "cpufreq",
1621         .subsys         = &cpu_subsys,
1622         .add_dev        = cpufreq_add_dev,
1623         .remove_dev     = cpufreq_remove_dev,
1624 };
1625
1626 /*
1627  * In case platform wants some specific frequency to be configured
1628  * during suspend..
1629  */
1630 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1631 {
1632         int ret;
1633
1634         if (!policy->suspend_freq) {
1635                 pr_err("%s: suspend_freq can't be zero\n", __func__);
1636                 return -EINVAL;
1637         }
1638
1639         pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1640                         policy->suspend_freq);
1641
1642         ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1643                         CPUFREQ_RELATION_H);
1644         if (ret)
1645                 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1646                                 __func__, policy->suspend_freq, ret);
1647
1648         return ret;
1649 }
1650 EXPORT_SYMBOL(cpufreq_generic_suspend);
1651
1652 /**
1653  * cpufreq_suspend() - Suspend CPUFreq governors
1654  *
1655  * Called during system wide Suspend/Hibernate cycles for suspending governors
1656  * as some platforms can't change frequency after this point in suspend cycle.
1657  * Because some of the devices (like: i2c, regulators, etc) they use for
1658  * changing frequency are suspended quickly after this point.
1659  */
1660 void cpufreq_suspend(void)
1661 {
1662         struct cpufreq_policy *policy;
1663
1664         if (!cpufreq_driver)
1665                 return;
1666
1667         if (!has_target())
1668                 return;
1669
1670         pr_debug("%s: Suspending Governors\n", __func__);
1671
1672         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1673                 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1674                         pr_err("%s: Failed to stop governor for policy: %p\n",
1675                                 __func__, policy);
1676                 else if (cpufreq_driver->suspend
1677                     && cpufreq_driver->suspend(policy))
1678                         pr_err("%s: Failed to suspend driver: %p\n", __func__,
1679                                 policy);
1680         }
1681
1682         cpufreq_suspended = true;
1683 }
1684
1685 /**
1686  * cpufreq_resume() - Resume CPUFreq governors
1687  *
1688  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1689  * are suspended with cpufreq_suspend().
1690  */
1691 void cpufreq_resume(void)
1692 {
1693         struct cpufreq_policy *policy;
1694
1695         if (!cpufreq_driver)
1696                 return;
1697
1698         if (!has_target())
1699                 return;
1700
1701         pr_debug("%s: Resuming Governors\n", __func__);
1702
1703         cpufreq_suspended = false;
1704
1705         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1706                 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1707                         pr_err("%s: Failed to resume driver: %p\n", __func__,
1708                                 policy);
1709                 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1710                     || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1711                         pr_err("%s: Failed to start governor for policy: %p\n",
1712                                 __func__, policy);
1713
1714                 /*
1715                  * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1716                  * policy in list. It will verify that the current freq is in
1717                  * sync with what we believe it to be.
1718                  */
1719                 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1720                         schedule_work(&policy->update);
1721         }
1722 }
1723
1724 /**
1725  *      cpufreq_get_current_driver - return current driver's name
1726  *
1727  *      Return the name string of the currently loaded cpufreq driver
1728  *      or NULL, if none.
1729  */
1730 const char *cpufreq_get_current_driver(void)
1731 {
1732         if (cpufreq_driver)
1733                 return cpufreq_driver->name;
1734
1735         return NULL;
1736 }
1737 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1738
1739 /*********************************************************************
1740  *                     NOTIFIER LISTS INTERFACE                      *
1741  *********************************************************************/
1742
1743 /**
1744  *      cpufreq_register_notifier - register a driver with cpufreq
1745  *      @nb: notifier function to register
1746  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1747  *
1748  *      Add a driver to one of two lists: either a list of drivers that
1749  *      are notified about clock rate changes (once before and once after
1750  *      the transition), or a list of drivers that are notified about
1751  *      changes in cpufreq policy.
1752  *
1753  *      This function may sleep, and has the same return conditions as
1754  *      blocking_notifier_chain_register.
1755  */
1756 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1757 {
1758         int ret;
1759
1760         if (cpufreq_disabled())
1761                 return -EINVAL;
1762
1763         WARN_ON(!init_cpufreq_transition_notifier_list_called);
1764
1765         switch (list) {
1766         case CPUFREQ_TRANSITION_NOTIFIER:
1767                 ret = srcu_notifier_chain_register(
1768                                 &cpufreq_transition_notifier_list, nb);
1769                 break;
1770         case CPUFREQ_POLICY_NOTIFIER:
1771                 ret = blocking_notifier_chain_register(
1772                                 &cpufreq_policy_notifier_list, nb);
1773                 break;
1774         default:
1775                 ret = -EINVAL;
1776         }
1777
1778         return ret;
1779 }
1780 EXPORT_SYMBOL(cpufreq_register_notifier);
1781
1782 /**
1783  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1784  *      @nb: notifier block to be unregistered
1785  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1786  *
1787  *      Remove a driver from the CPU frequency notifier list.
1788  *
1789  *      This function may sleep, and has the same return conditions as
1790  *      blocking_notifier_chain_unregister.
1791  */
1792 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1793 {
1794         int ret;
1795
1796         if (cpufreq_disabled())
1797                 return -EINVAL;
1798
1799         switch (list) {
1800         case CPUFREQ_TRANSITION_NOTIFIER:
1801                 ret = srcu_notifier_chain_unregister(
1802                                 &cpufreq_transition_notifier_list, nb);
1803                 break;
1804         case CPUFREQ_POLICY_NOTIFIER:
1805                 ret = blocking_notifier_chain_unregister(
1806                                 &cpufreq_policy_notifier_list, nb);
1807                 break;
1808         default:
1809                 ret = -EINVAL;
1810         }
1811
1812         return ret;
1813 }
1814 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1815
1816
1817 /*********************************************************************
1818  *                              GOVERNORS                            *
1819  *********************************************************************/
1820
1821 /* Must set freqs->new to intermediate frequency */
1822 static int __target_intermediate(struct cpufreq_policy *policy,
1823                                  struct cpufreq_freqs *freqs, int index)
1824 {
1825         int ret;
1826
1827         freqs->new = cpufreq_driver->get_intermediate(policy, index);
1828
1829         /* We don't need to switch to intermediate freq */
1830         if (!freqs->new)
1831                 return 0;
1832
1833         pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1834                  __func__, policy->cpu, freqs->old, freqs->new);
1835
1836         cpufreq_freq_transition_begin(policy, freqs);
1837         ret = cpufreq_driver->target_intermediate(policy, index);
1838         cpufreq_freq_transition_end(policy, freqs, ret);
1839
1840         if (ret)
1841                 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1842                        __func__, ret);
1843
1844         return ret;
1845 }
1846
1847 static int __target_index(struct cpufreq_policy *policy,
1848                           struct cpufreq_frequency_table *freq_table, int index)
1849 {
1850         struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1851         unsigned int intermediate_freq = 0;
1852         int retval = -EINVAL;
1853         bool notify;
1854
1855         notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1856         if (notify) {
1857                 /* Handle switching to intermediate frequency */
1858                 if (cpufreq_driver->get_intermediate) {
1859                         retval = __target_intermediate(policy, &freqs, index);
1860                         if (retval)
1861                                 return retval;
1862
1863                         intermediate_freq = freqs.new;
1864                         /* Set old freq to intermediate */
1865                         if (intermediate_freq)
1866                                 freqs.old = freqs.new;
1867                 }
1868
1869                 freqs.new = freq_table[index].frequency;
1870                 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1871                          __func__, policy->cpu, freqs.old, freqs.new);
1872
1873                 cpufreq_freq_transition_begin(policy, &freqs);
1874         }
1875
1876         retval = cpufreq_driver->target_index(policy, index);
1877         if (retval)
1878                 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1879                        retval);
1880
1881         if (notify) {
1882                 cpufreq_freq_transition_end(policy, &freqs, retval);
1883
1884                 /*
1885                  * Failed after setting to intermediate freq? Driver should have
1886                  * reverted back to initial frequency and so should we. Check
1887                  * here for intermediate_freq instead of get_intermediate, in
1888                  * case we have't switched to intermediate freq at all.
1889                  */
1890                 if (unlikely(retval && intermediate_freq)) {
1891                         freqs.old = intermediate_freq;
1892                         freqs.new = policy->restore_freq;
1893                         cpufreq_freq_transition_begin(policy, &freqs);
1894                         cpufreq_freq_transition_end(policy, &freqs, 0);
1895                 }
1896         }
1897
1898         return retval;
1899 }
1900
1901 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1902                             unsigned int target_freq,
1903                             unsigned int relation)
1904 {
1905         unsigned int old_target_freq = target_freq;
1906         int retval = -EINVAL;
1907
1908         if (cpufreq_disabled())
1909                 return -ENODEV;
1910
1911         /* Make sure that target_freq is within supported range */
1912         if (target_freq > policy->max)
1913                 target_freq = policy->max;
1914         if (target_freq < policy->min)
1915                 target_freq = policy->min;
1916
1917         pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1918                  policy->cpu, target_freq, relation, old_target_freq);
1919
1920         /*
1921          * This might look like a redundant call as we are checking it again
1922          * after finding index. But it is left intentionally for cases where
1923          * exactly same freq is called again and so we can save on few function
1924          * calls.
1925          */
1926         if (target_freq == policy->cur)
1927                 return 0;
1928
1929         /* Save last value to restore later on errors */
1930         policy->restore_freq = policy->cur;
1931
1932         if (cpufreq_driver->target)
1933                 retval = cpufreq_driver->target(policy, target_freq, relation);
1934         else if (cpufreq_driver->target_index) {
1935                 struct cpufreq_frequency_table *freq_table;
1936                 int index;
1937
1938                 freq_table = cpufreq_frequency_get_table(policy->cpu);
1939                 if (unlikely(!freq_table)) {
1940                         pr_err("%s: Unable to find freq_table\n", __func__);
1941                         goto out;
1942                 }
1943
1944                 retval = cpufreq_frequency_table_target(policy, freq_table,
1945                                 target_freq, relation, &index);
1946                 if (unlikely(retval)) {
1947                         pr_err("%s: Unable to find matching freq\n", __func__);
1948                         goto out;
1949                 }
1950
1951                 if (freq_table[index].frequency == policy->cur) {
1952                         retval = 0;
1953                         goto out;
1954                 }
1955
1956                 retval = __target_index(policy, freq_table, index);
1957         }
1958
1959 out:
1960         return retval;
1961 }
1962 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1963
1964 int cpufreq_driver_target(struct cpufreq_policy *policy,
1965                           unsigned int target_freq,
1966                           unsigned int relation)
1967 {
1968         int ret = -EINVAL;
1969
1970         down_write(&policy->rwsem);
1971
1972         ret = __cpufreq_driver_target(policy, target_freq, relation);
1973
1974         up_write(&policy->rwsem);
1975
1976         return ret;
1977 }
1978 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1979
1980 /*
1981  * when "event" is CPUFREQ_GOV_LIMITS
1982  */
1983
1984 static int __cpufreq_governor(struct cpufreq_policy *policy,
1985                                         unsigned int event)
1986 {
1987         int ret;
1988
1989         /* Only must be defined when default governor is known to have latency
1990            restrictions, like e.g. conservative or ondemand.
1991            That this is the case is already ensured in Kconfig
1992         */
1993 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1994         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1995 #else
1996         struct cpufreq_governor *gov = NULL;
1997 #endif
1998
1999         /* Don't start any governor operations if we are entering suspend */
2000         if (cpufreq_suspended)
2001                 return 0;
2002
2003         if (policy->governor->max_transition_latency &&
2004             policy->cpuinfo.transition_latency >
2005             policy->governor->max_transition_latency) {
2006                 if (!gov)
2007                         return -EINVAL;
2008                 else {
2009                         pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2010                                 policy->governor->name, gov->name);
2011                         policy->governor = gov;
2012                 }
2013         }
2014
2015         if (event == CPUFREQ_GOV_POLICY_INIT)
2016                 if (!try_module_get(policy->governor->owner))
2017                         return -EINVAL;
2018
2019         pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2020                  policy->cpu, event);
2021
2022         mutex_lock(&cpufreq_governor_lock);
2023         if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2024             || (!policy->governor_enabled
2025             && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2026                 mutex_unlock(&cpufreq_governor_lock);
2027                 return -EBUSY;
2028         }
2029
2030         if (event == CPUFREQ_GOV_STOP)
2031                 policy->governor_enabled = false;
2032         else if (event == CPUFREQ_GOV_START)
2033                 policy->governor_enabled = true;
2034
2035         mutex_unlock(&cpufreq_governor_lock);
2036
2037         ret = policy->governor->governor(policy, event);
2038
2039         if (!ret) {
2040                 if (event == CPUFREQ_GOV_POLICY_INIT)
2041                         policy->governor->initialized++;
2042                 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2043                         policy->governor->initialized--;
2044         } else {
2045                 /* Restore original values */
2046                 mutex_lock(&cpufreq_governor_lock);
2047                 if (event == CPUFREQ_GOV_STOP)
2048                         policy->governor_enabled = true;
2049                 else if (event == CPUFREQ_GOV_START)
2050                         policy->governor_enabled = false;
2051                 mutex_unlock(&cpufreq_governor_lock);
2052         }
2053
2054         if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2055                         ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2056                 module_put(policy->governor->owner);
2057
2058         return ret;
2059 }
2060
2061 int cpufreq_register_governor(struct cpufreq_governor *governor)
2062 {
2063         int err;
2064
2065         if (!governor)
2066                 return -EINVAL;
2067
2068         if (cpufreq_disabled())
2069                 return -ENODEV;
2070
2071         mutex_lock(&cpufreq_governor_mutex);
2072
2073         governor->initialized = 0;
2074         err = -EBUSY;
2075         if (__find_governor(governor->name) == NULL) {
2076                 err = 0;
2077                 list_add(&governor->governor_list, &cpufreq_governor_list);
2078         }
2079
2080         mutex_unlock(&cpufreq_governor_mutex);
2081         return err;
2082 }
2083 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2084
2085 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2086 {
2087         int cpu;
2088
2089         if (!governor)
2090                 return;
2091
2092         if (cpufreq_disabled())
2093                 return;
2094
2095         for_each_present_cpu(cpu) {
2096                 if (cpu_online(cpu))
2097                         continue;
2098                 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2099                         strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2100         }
2101
2102         mutex_lock(&cpufreq_governor_mutex);
2103         list_del(&governor->governor_list);
2104         mutex_unlock(&cpufreq_governor_mutex);
2105         return;
2106 }
2107 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2108
2109
2110 /*********************************************************************
2111  *                          POLICY INTERFACE                         *
2112  *********************************************************************/
2113
2114 /**
2115  * cpufreq_get_policy - get the current cpufreq_policy
2116  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2117  *      is written
2118  *
2119  * Reads the current cpufreq policy.
2120  */
2121 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2122 {
2123         struct cpufreq_policy *cpu_policy;
2124         if (!policy)
2125                 return -EINVAL;
2126
2127         cpu_policy = cpufreq_cpu_get(cpu);
2128         if (!cpu_policy)
2129                 return -EINVAL;
2130
2131         memcpy(policy, cpu_policy, sizeof(*policy));
2132
2133         cpufreq_cpu_put(cpu_policy);
2134         return 0;
2135 }
2136 EXPORT_SYMBOL(cpufreq_get_policy);
2137
2138 /*
2139  * policy : current policy.
2140  * new_policy: policy to be set.
2141  */
2142 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2143                                 struct cpufreq_policy *new_policy)
2144 {
2145         struct cpufreq_governor *old_gov;
2146         int ret;
2147
2148         pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2149                  new_policy->cpu, new_policy->min, new_policy->max);
2150
2151         memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2152
2153         if (new_policy->min > policy->max || new_policy->max < policy->min)
2154                 return -EINVAL;
2155
2156         /* verify the cpu speed can be set within this limit */
2157         ret = cpufreq_driver->verify(new_policy);
2158         if (ret)
2159                 return ret;
2160
2161         /* adjust if necessary - all reasons */
2162         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2163                         CPUFREQ_ADJUST, new_policy);
2164
2165         /* adjust if necessary - hardware incompatibility*/
2166         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2167                         CPUFREQ_INCOMPATIBLE, new_policy);
2168
2169         /*
2170          * verify the cpu speed can be set within this limit, which might be
2171          * different to the first one
2172          */
2173         ret = cpufreq_driver->verify(new_policy);
2174         if (ret)
2175                 return ret;
2176
2177         /* notification of the new policy */
2178         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2179                         CPUFREQ_NOTIFY, new_policy);
2180
2181         policy->min = new_policy->min;
2182         policy->max = new_policy->max;
2183
2184         pr_debug("new min and max freqs are %u - %u kHz\n",
2185                  policy->min, policy->max);
2186
2187         if (cpufreq_driver->setpolicy) {
2188                 policy->policy = new_policy->policy;
2189                 pr_debug("setting range\n");
2190                 return cpufreq_driver->setpolicy(new_policy);
2191         }
2192
2193         if (new_policy->governor == policy->governor)
2194                 goto out;
2195
2196         pr_debug("governor switch\n");
2197
2198         /* save old, working values */
2199         old_gov = policy->governor;
2200         /* end old governor */
2201         if (old_gov) {
2202                 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2203                 up_write(&policy->rwsem);
2204                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2205                 down_write(&policy->rwsem);
2206         }
2207
2208         /* start new governor */
2209         policy->governor = new_policy->governor;
2210         if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2211                 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2212                         goto out;
2213
2214                 up_write(&policy->rwsem);
2215                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2216                 down_write(&policy->rwsem);
2217         }
2218
2219         /* new governor failed, so re-start old one */
2220         pr_debug("starting governor %s failed\n", policy->governor->name);
2221         if (old_gov) {
2222                 policy->governor = old_gov;
2223                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2224                 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2225         }
2226
2227         return -EINVAL;
2228
2229  out:
2230         pr_debug("governor: change or update limits\n");
2231         return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2232 }
2233
2234 /**
2235  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
2236  *      @cpu: CPU which shall be re-evaluated
2237  *
2238  *      Useful for policy notifiers which have different necessities
2239  *      at different times.
2240  */
2241 int cpufreq_update_policy(unsigned int cpu)
2242 {
2243         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2244         struct cpufreq_policy new_policy;
2245         int ret;
2246
2247         if (!policy)
2248                 return -ENODEV;
2249
2250         down_write(&policy->rwsem);
2251
2252         pr_debug("updating policy for CPU %u\n", cpu);
2253         memcpy(&new_policy, policy, sizeof(*policy));
2254         new_policy.min = policy->user_policy.min;
2255         new_policy.max = policy->user_policy.max;
2256         new_policy.policy = policy->user_policy.policy;
2257         new_policy.governor = policy->user_policy.governor;
2258
2259         /*
2260          * BIOS might change freq behind our back
2261          * -> ask driver for current freq and notify governors about a change
2262          */
2263         if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2264                 new_policy.cur = cpufreq_driver->get(cpu);
2265                 if (WARN_ON(!new_policy.cur)) {
2266                         ret = -EIO;
2267                         goto unlock;
2268                 }
2269
2270                 if (!policy->cur) {
2271                         pr_debug("Driver did not initialize current freq\n");
2272                         policy->cur = new_policy.cur;
2273                 } else {
2274                         if (policy->cur != new_policy.cur && has_target())
2275                                 cpufreq_out_of_sync(cpu, policy->cur,
2276                                                                 new_policy.cur);
2277                 }
2278         }
2279
2280         ret = cpufreq_set_policy(policy, &new_policy);
2281
2282 unlock:
2283         up_write(&policy->rwsem);
2284
2285         cpufreq_cpu_put(policy);
2286         return ret;
2287 }
2288 EXPORT_SYMBOL(cpufreq_update_policy);
2289
2290 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2291                                         unsigned long action, void *hcpu)
2292 {
2293         unsigned int cpu = (unsigned long)hcpu;
2294         struct device *dev;
2295
2296         dev = get_cpu_device(cpu);
2297         if (dev) {
2298                 switch (action & ~CPU_TASKS_FROZEN) {
2299                 case CPU_ONLINE:
2300                         __cpufreq_add_dev(dev, NULL);
2301                         break;
2302
2303                 case CPU_DOWN_PREPARE:
2304                         __cpufreq_remove_dev_prepare(dev, NULL);
2305                         break;
2306
2307                 case CPU_POST_DEAD:
2308                         __cpufreq_remove_dev_finish(dev, NULL);
2309                         break;
2310
2311                 case CPU_DOWN_FAILED:
2312                         __cpufreq_add_dev(dev, NULL);
2313                         break;
2314                 }
2315         }
2316         return NOTIFY_OK;
2317 }
2318
2319 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2320         .notifier_call = cpufreq_cpu_callback,
2321 };
2322
2323 /*********************************************************************
2324  *               BOOST                                               *
2325  *********************************************************************/
2326 static int cpufreq_boost_set_sw(int state)
2327 {
2328         struct cpufreq_frequency_table *freq_table;
2329         struct cpufreq_policy *policy;
2330         int ret = -EINVAL;
2331
2332         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2333                 freq_table = cpufreq_frequency_get_table(policy->cpu);
2334                 if (freq_table) {
2335                         ret = cpufreq_frequency_table_cpuinfo(policy,
2336                                                         freq_table);
2337                         if (ret) {
2338                                 pr_err("%s: Policy frequency update failed\n",
2339                                        __func__);
2340                                 break;
2341                         }
2342                         policy->user_policy.max = policy->max;
2343                         __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2344                 }
2345         }
2346
2347         return ret;
2348 }
2349
2350 int cpufreq_boost_trigger_state(int state)
2351 {
2352         unsigned long flags;
2353         int ret = 0;
2354
2355         if (cpufreq_driver->boost_enabled == state)
2356                 return 0;
2357
2358         write_lock_irqsave(&cpufreq_driver_lock, flags);
2359         cpufreq_driver->boost_enabled = state;
2360         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2361
2362         ret = cpufreq_driver->set_boost(state);
2363         if (ret) {
2364                 write_lock_irqsave(&cpufreq_driver_lock, flags);
2365                 cpufreq_driver->boost_enabled = !state;
2366                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2367
2368                 pr_err("%s: Cannot %s BOOST\n",
2369                        __func__, state ? "enable" : "disable");
2370         }
2371
2372         return ret;
2373 }
2374
2375 int cpufreq_boost_supported(void)
2376 {
2377         if (likely(cpufreq_driver))
2378                 return cpufreq_driver->boost_supported;
2379
2380         return 0;
2381 }
2382 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2383
2384 int cpufreq_boost_enabled(void)
2385 {
2386         return cpufreq_driver->boost_enabled;
2387 }
2388 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2389
2390 /*********************************************************************
2391  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2392  *********************************************************************/
2393
2394 /**
2395  * cpufreq_register_driver - register a CPU Frequency driver
2396  * @driver_data: A struct cpufreq_driver containing the values#
2397  * submitted by the CPU Frequency driver.
2398  *
2399  * Registers a CPU Frequency driver to this core code. This code
2400  * returns zero on success, -EBUSY when another driver got here first
2401  * (and isn't unregistered in the meantime).
2402  *
2403  */
2404 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2405 {
2406         unsigned long flags;
2407         int ret;
2408
2409         if (cpufreq_disabled())
2410                 return -ENODEV;
2411
2412         if (!driver_data || !driver_data->verify || !driver_data->init ||
2413             !(driver_data->setpolicy || driver_data->target_index ||
2414                     driver_data->target) ||
2415              (driver_data->setpolicy && (driver_data->target_index ||
2416                     driver_data->target)) ||
2417              (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2418                 return -EINVAL;
2419
2420         pr_debug("trying to register driver %s\n", driver_data->name);
2421
2422         if (driver_data->setpolicy)
2423                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2424
2425         write_lock_irqsave(&cpufreq_driver_lock, flags);
2426         if (cpufreq_driver) {
2427                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2428                 return -EEXIST;
2429         }
2430         cpufreq_driver = driver_data;
2431         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2432
2433         if (cpufreq_boost_supported()) {
2434                 /*
2435                  * Check if driver provides function to enable boost -
2436                  * if not, use cpufreq_boost_set_sw as default
2437                  */
2438                 if (!cpufreq_driver->set_boost)
2439                         cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2440
2441                 ret = cpufreq_sysfs_create_file(&boost.attr);
2442                 if (ret) {
2443                         pr_err("%s: cannot register global BOOST sysfs file\n",
2444                                __func__);
2445                         goto err_null_driver;
2446                 }
2447         }
2448
2449         ret = subsys_interface_register(&cpufreq_interface);
2450         if (ret)
2451                 goto err_boost_unreg;
2452
2453         if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2454                 int i;
2455                 ret = -ENODEV;
2456
2457                 /* check for at least one working CPU */
2458                 for (i = 0; i < nr_cpu_ids; i++)
2459                         if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2460                                 ret = 0;
2461                                 break;
2462                         }
2463
2464                 /* if all ->init() calls failed, unregister */
2465                 if (ret) {
2466                         pr_debug("no CPU initialized for driver %s\n",
2467                                  driver_data->name);
2468                         goto err_if_unreg;
2469                 }
2470         }
2471
2472         register_hotcpu_notifier(&cpufreq_cpu_notifier);
2473         pr_debug("driver %s up and running\n", driver_data->name);
2474
2475         return 0;
2476 err_if_unreg:
2477         subsys_interface_unregister(&cpufreq_interface);
2478 err_boost_unreg:
2479         if (cpufreq_boost_supported())
2480                 cpufreq_sysfs_remove_file(&boost.attr);
2481 err_null_driver:
2482         write_lock_irqsave(&cpufreq_driver_lock, flags);
2483         cpufreq_driver = NULL;
2484         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2485         return ret;
2486 }
2487 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2488
2489 /**
2490  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2491  *
2492  * Unregister the current CPUFreq driver. Only call this if you have
2493  * the right to do so, i.e. if you have succeeded in initialising before!
2494  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2495  * currently not initialised.
2496  */
2497 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2498 {
2499         unsigned long flags;
2500
2501         if (!cpufreq_driver || (driver != cpufreq_driver))
2502                 return -EINVAL;
2503
2504         pr_debug("unregistering driver %s\n", driver->name);
2505
2506         subsys_interface_unregister(&cpufreq_interface);
2507         if (cpufreq_boost_supported())
2508                 cpufreq_sysfs_remove_file(&boost.attr);
2509
2510         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2511
2512         down_write(&cpufreq_rwsem);
2513         write_lock_irqsave(&cpufreq_driver_lock, flags);
2514
2515         cpufreq_driver = NULL;
2516
2517         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2518         up_write(&cpufreq_rwsem);
2519
2520         return 0;
2521 }
2522 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2523
2524 static int __init cpufreq_core_init(void)
2525 {
2526         if (cpufreq_disabled())
2527                 return -ENODEV;
2528
2529         cpufreq_global_kobject = kobject_create();
2530         BUG_ON(!cpufreq_global_kobject);
2531
2532         return 0;
2533 }
2534 core_initcall(cpufreq_core_init);