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 int update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu,
1080                              struct device *cpu_dev)
1081 {
1082         int ret;
1083
1084         if (WARN_ON(cpu == policy->cpu))
1085                 return 0;
1086
1087         /* Move kobject to the new policy->cpu */
1088         ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1089         if (ret) {
1090                 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1091                 return ret;
1092         }
1093
1094         down_write(&policy->rwsem);
1095
1096         policy->last_cpu = policy->cpu;
1097         policy->cpu = cpu;
1098
1099         up_write(&policy->rwsem);
1100
1101         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1102                         CPUFREQ_UPDATE_POLICY_CPU, policy);
1103
1104         return 0;
1105 }
1106
1107 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1108 {
1109         unsigned int j, cpu = dev->id;
1110         int ret = -ENOMEM;
1111         struct cpufreq_policy *policy;
1112         unsigned long flags;
1113         bool recover_policy = cpufreq_suspended;
1114 #ifdef CONFIG_HOTPLUG_CPU
1115         struct cpufreq_policy *tpolicy;
1116 #endif
1117
1118         if (cpu_is_offline(cpu))
1119                 return 0;
1120
1121         pr_debug("adding CPU %u\n", cpu);
1122
1123 #ifdef CONFIG_SMP
1124         /* check whether a different CPU already registered this
1125          * CPU because it is in the same boat. */
1126         policy = cpufreq_cpu_get(cpu);
1127         if (unlikely(policy)) {
1128                 cpufreq_cpu_put(policy);
1129                 return 0;
1130         }
1131 #endif
1132
1133         if (!down_read_trylock(&cpufreq_rwsem))
1134                 return 0;
1135
1136 #ifdef CONFIG_HOTPLUG_CPU
1137         /* Check if this cpu was hot-unplugged earlier and has siblings */
1138         read_lock_irqsave(&cpufreq_driver_lock, flags);
1139         list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1140                 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1141                         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1142                         ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1143                         up_read(&cpufreq_rwsem);
1144                         return ret;
1145                 }
1146         }
1147         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1148 #endif
1149
1150         /*
1151          * Restore the saved policy when doing light-weight init and fall back
1152          * to the full init if that fails.
1153          */
1154         policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1155         if (!policy) {
1156                 recover_policy = false;
1157                 policy = cpufreq_policy_alloc();
1158                 if (!policy)
1159                         goto nomem_out;
1160         }
1161
1162         /*
1163          * In the resume path, since we restore a saved policy, the assignment
1164          * to policy->cpu is like an update of the existing policy, rather than
1165          * the creation of a brand new one. So we need to perform this update
1166          * by invoking update_policy_cpu().
1167          */
1168         if (recover_policy && cpu != policy->cpu)
1169                 WARN_ON(update_policy_cpu(policy, cpu, dev));
1170         else
1171                 policy->cpu = cpu;
1172
1173         cpumask_copy(policy->cpus, cpumask_of(cpu));
1174
1175         init_completion(&policy->kobj_unregister);
1176         INIT_WORK(&policy->update, handle_update);
1177
1178         /* call driver. From then on the cpufreq must be able
1179          * to accept all calls to ->verify and ->setpolicy for this CPU
1180          */
1181         ret = cpufreq_driver->init(policy);
1182         if (ret) {
1183                 pr_debug("initialization failed\n");
1184                 goto err_set_policy_cpu;
1185         }
1186
1187         /* related cpus should atleast have policy->cpus */
1188         cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1189
1190         /*
1191          * affected cpus must always be the one, which are online. We aren't
1192          * managing offline cpus here.
1193          */
1194         cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1195
1196         if (!recover_policy) {
1197                 policy->user_policy.min = policy->min;
1198                 policy->user_policy.max = policy->max;
1199         }
1200
1201         down_write(&policy->rwsem);
1202         write_lock_irqsave(&cpufreq_driver_lock, flags);
1203         for_each_cpu(j, policy->cpus)
1204                 per_cpu(cpufreq_cpu_data, j) = policy;
1205         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1206
1207         if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1208                 policy->cur = cpufreq_driver->get(policy->cpu);
1209                 if (!policy->cur) {
1210                         pr_err("%s: ->get() failed\n", __func__);
1211                         goto err_get_freq;
1212                 }
1213         }
1214
1215         /*
1216          * Sometimes boot loaders set CPU frequency to a value outside of
1217          * frequency table present with cpufreq core. In such cases CPU might be
1218          * unstable if it has to run on that frequency for long duration of time
1219          * and so its better to set it to a frequency which is specified in
1220          * freq-table. This also makes cpufreq stats inconsistent as
1221          * cpufreq-stats would fail to register because current frequency of CPU
1222          * isn't found in freq-table.
1223          *
1224          * Because we don't want this change to effect boot process badly, we go
1225          * for the next freq which is >= policy->cur ('cur' must be set by now,
1226          * otherwise we will end up setting freq to lowest of the table as 'cur'
1227          * is initialized to zero).
1228          *
1229          * We are passing target-freq as "policy->cur - 1" otherwise
1230          * __cpufreq_driver_target() would simply fail, as policy->cur will be
1231          * equal to target-freq.
1232          */
1233         if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1234             && has_target()) {
1235                 /* Are we running at unknown frequency ? */
1236                 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1237                 if (ret == -EINVAL) {
1238                         /* Warn user and fix it */
1239                         pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1240                                 __func__, policy->cpu, policy->cur);
1241                         ret = __cpufreq_driver_target(policy, policy->cur - 1,
1242                                 CPUFREQ_RELATION_L);
1243
1244                         /*
1245                          * Reaching here after boot in a few seconds may not
1246                          * mean that system will remain stable at "unknown"
1247                          * frequency for longer duration. Hence, a BUG_ON().
1248                          */
1249                         BUG_ON(ret);
1250                         pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1251                                 __func__, policy->cpu, policy->cur);
1252                 }
1253         }
1254
1255         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1256                                      CPUFREQ_START, policy);
1257
1258         if (!recover_policy) {
1259                 ret = cpufreq_add_dev_interface(policy, dev);
1260                 if (ret)
1261                         goto err_out_unregister;
1262                 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1263                                 CPUFREQ_CREATE_POLICY, policy);
1264         }
1265
1266         write_lock_irqsave(&cpufreq_driver_lock, flags);
1267         list_add(&policy->policy_list, &cpufreq_policy_list);
1268         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1269
1270         cpufreq_init_policy(policy);
1271
1272         if (!recover_policy) {
1273                 policy->user_policy.policy = policy->policy;
1274                 policy->user_policy.governor = policy->governor;
1275         }
1276         up_write(&policy->rwsem);
1277
1278         kobject_uevent(&policy->kobj, KOBJ_ADD);
1279         up_read(&cpufreq_rwsem);
1280
1281         pr_debug("initialization complete\n");
1282
1283         return 0;
1284
1285 err_out_unregister:
1286 err_get_freq:
1287         write_lock_irqsave(&cpufreq_driver_lock, flags);
1288         for_each_cpu(j, policy->cpus)
1289                 per_cpu(cpufreq_cpu_data, j) = NULL;
1290         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1291
1292         if (cpufreq_driver->exit)
1293                 cpufreq_driver->exit(policy);
1294 err_set_policy_cpu:
1295         if (recover_policy) {
1296                 /* Do not leave stale fallback data behind. */
1297                 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1298                 cpufreq_policy_put_kobj(policy);
1299         }
1300         cpufreq_policy_free(policy);
1301
1302 nomem_out:
1303         up_read(&cpufreq_rwsem);
1304
1305         return ret;
1306 }
1307
1308 /**
1309  * cpufreq_add_dev - add a CPU device
1310  *
1311  * Adds the cpufreq interface for a CPU device.
1312  *
1313  * The Oracle says: try running cpufreq registration/unregistration concurrently
1314  * with with cpu hotplugging and all hell will break loose. Tried to clean this
1315  * mess up, but more thorough testing is needed. - Mathieu
1316  */
1317 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1318 {
1319         return __cpufreq_add_dev(dev, sif);
1320 }
1321
1322 static int __cpufreq_remove_dev_prepare(struct device *dev,
1323                                         struct subsys_interface *sif)
1324 {
1325         unsigned int cpu = dev->id, cpus;
1326         int ret;
1327         unsigned long flags;
1328         struct cpufreq_policy *policy;
1329
1330         pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1331
1332         write_lock_irqsave(&cpufreq_driver_lock, flags);
1333
1334         policy = per_cpu(cpufreq_cpu_data, cpu);
1335
1336         /* Save the policy somewhere when doing a light-weight tear-down */
1337         if (cpufreq_suspended)
1338                 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1339
1340         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1341
1342         if (!policy) {
1343                 pr_debug("%s: No cpu_data found\n", __func__);
1344                 return -EINVAL;
1345         }
1346
1347         if (has_target()) {
1348                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1349                 if (ret) {
1350                         pr_err("%s: Failed to stop governor\n", __func__);
1351                         return ret;
1352                 }
1353         }
1354
1355         if (!cpufreq_driver->setpolicy)
1356                 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1357                         policy->governor->name, CPUFREQ_NAME_LEN);
1358
1359         down_read(&policy->rwsem);
1360         cpus = cpumask_weight(policy->cpus);
1361         up_read(&policy->rwsem);
1362
1363         if (cpu != policy->cpu) {
1364                 sysfs_remove_link(&dev->kobj, "cpufreq");
1365         } else if (cpus > 1) {
1366                 /* Nominate new CPU */
1367                 int new_cpu = cpumask_any_but(policy->cpus, cpu);
1368                 struct device *cpu_dev = get_cpu_device(new_cpu);
1369
1370                 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1371                 ret = update_policy_cpu(policy, new_cpu, cpu_dev);
1372                 if (ret) {
1373                         if (sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1374                                               "cpufreq"))
1375                                 pr_err("%s: Failed to restore kobj link to cpu:%d\n",
1376                                        __func__, cpu_dev->id);
1377                         return ret;
1378                 }
1379
1380                 if (!cpufreq_suspended)
1381                         pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1382                                  __func__, new_cpu, cpu);
1383         } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
1384                 cpufreq_driver->stop_cpu(policy);
1385         }
1386
1387         return 0;
1388 }
1389
1390 static int __cpufreq_remove_dev_finish(struct device *dev,
1391                                        struct subsys_interface *sif)
1392 {
1393         unsigned int cpu = dev->id, cpus;
1394         int ret;
1395         unsigned long flags;
1396         struct cpufreq_policy *policy;
1397
1398         read_lock_irqsave(&cpufreq_driver_lock, flags);
1399         policy = per_cpu(cpufreq_cpu_data, cpu);
1400         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1401
1402         if (!policy) {
1403                 pr_debug("%s: No cpu_data found\n", __func__);
1404                 return -EINVAL;
1405         }
1406
1407         down_write(&policy->rwsem);
1408         cpus = cpumask_weight(policy->cpus);
1409
1410         if (cpus > 1)
1411                 cpumask_clear_cpu(cpu, policy->cpus);
1412         up_write(&policy->rwsem);
1413
1414         /* If cpu is last user of policy, free policy */
1415         if (cpus == 1) {
1416                 if (has_target()) {
1417                         ret = __cpufreq_governor(policy,
1418                                         CPUFREQ_GOV_POLICY_EXIT);
1419                         if (ret) {
1420                                 pr_err("%s: Failed to exit governor\n",
1421                                        __func__);
1422                                 return ret;
1423                         }
1424                 }
1425
1426                 if (!cpufreq_suspended)
1427                         cpufreq_policy_put_kobj(policy);
1428
1429                 /*
1430                  * Perform the ->exit() even during light-weight tear-down,
1431                  * since this is a core component, and is essential for the
1432                  * subsequent light-weight ->init() to succeed.
1433                  */
1434                 if (cpufreq_driver->exit)
1435                         cpufreq_driver->exit(policy);
1436
1437                 /* Remove policy from list of active policies */
1438                 write_lock_irqsave(&cpufreq_driver_lock, flags);
1439                 list_del(&policy->policy_list);
1440                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1441
1442                 if (!cpufreq_suspended)
1443                         cpufreq_policy_free(policy);
1444         } else if (has_target()) {
1445                 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1446                 if (!ret)
1447                         ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1448
1449                 if (ret) {
1450                         pr_err("%s: Failed to start governor\n", __func__);
1451                         return ret;
1452                 }
1453         }
1454
1455         per_cpu(cpufreq_cpu_data, cpu) = NULL;
1456         return 0;
1457 }
1458
1459 /**
1460  * cpufreq_remove_dev - remove a CPU device
1461  *
1462  * Removes the cpufreq interface for a CPU device.
1463  */
1464 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1465 {
1466         unsigned int cpu = dev->id;
1467         int ret;
1468
1469         if (cpu_is_offline(cpu))
1470                 return 0;
1471
1472         ret = __cpufreq_remove_dev_prepare(dev, sif);
1473
1474         if (!ret)
1475                 ret = __cpufreq_remove_dev_finish(dev, sif);
1476
1477         return ret;
1478 }
1479
1480 static void handle_update(struct work_struct *work)
1481 {
1482         struct cpufreq_policy *policy =
1483                 container_of(work, struct cpufreq_policy, update);
1484         unsigned int cpu = policy->cpu;
1485         pr_debug("handle_update for cpu %u called\n", cpu);
1486         cpufreq_update_policy(cpu);
1487 }
1488
1489 /**
1490  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1491  *      in deep trouble.
1492  *      @cpu: cpu number
1493  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
1494  *      @new_freq: CPU frequency the CPU actually runs at
1495  *
1496  *      We adjust to current frequency first, and need to clean up later.
1497  *      So either call to cpufreq_update_policy() or schedule handle_update()).
1498  */
1499 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1500                                 unsigned int new_freq)
1501 {
1502         struct cpufreq_policy *policy;
1503         struct cpufreq_freqs freqs;
1504         unsigned long flags;
1505
1506         pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1507                  old_freq, new_freq);
1508
1509         freqs.old = old_freq;
1510         freqs.new = new_freq;
1511
1512         read_lock_irqsave(&cpufreq_driver_lock, flags);
1513         policy = per_cpu(cpufreq_cpu_data, cpu);
1514         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1515
1516         cpufreq_freq_transition_begin(policy, &freqs);
1517         cpufreq_freq_transition_end(policy, &freqs, 0);
1518 }
1519
1520 /**
1521  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1522  * @cpu: CPU number
1523  *
1524  * This is the last known freq, without actually getting it from the driver.
1525  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1526  */
1527 unsigned int cpufreq_quick_get(unsigned int cpu)
1528 {
1529         struct cpufreq_policy *policy;
1530         unsigned int ret_freq = 0;
1531
1532         if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1533                 return cpufreq_driver->get(cpu);
1534
1535         policy = cpufreq_cpu_get(cpu);
1536         if (policy) {
1537                 ret_freq = policy->cur;
1538                 cpufreq_cpu_put(policy);
1539         }
1540
1541         return ret_freq;
1542 }
1543 EXPORT_SYMBOL(cpufreq_quick_get);
1544
1545 /**
1546  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1547  * @cpu: CPU number
1548  *
1549  * Just return the max possible frequency for a given CPU.
1550  */
1551 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1552 {
1553         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1554         unsigned int ret_freq = 0;
1555
1556         if (policy) {
1557                 ret_freq = policy->max;
1558                 cpufreq_cpu_put(policy);
1559         }
1560
1561         return ret_freq;
1562 }
1563 EXPORT_SYMBOL(cpufreq_quick_get_max);
1564
1565 static unsigned int __cpufreq_get(unsigned int cpu)
1566 {
1567         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1568         unsigned int ret_freq = 0;
1569
1570         if (!cpufreq_driver->get)
1571                 return ret_freq;
1572
1573         ret_freq = cpufreq_driver->get(cpu);
1574
1575         if (ret_freq && policy->cur &&
1576                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1577                 /* verify no discrepancy between actual and
1578                                         saved value exists */
1579                 if (unlikely(ret_freq != policy->cur)) {
1580                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1581                         schedule_work(&policy->update);
1582                 }
1583         }
1584
1585         return ret_freq;
1586 }
1587
1588 /**
1589  * cpufreq_get - get the current CPU frequency (in kHz)
1590  * @cpu: CPU number
1591  *
1592  * Get the CPU current (static) CPU frequency
1593  */
1594 unsigned int cpufreq_get(unsigned int cpu)
1595 {
1596         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1597         unsigned int ret_freq = 0;
1598
1599         if (policy) {
1600                 down_read(&policy->rwsem);
1601                 ret_freq = __cpufreq_get(cpu);
1602                 up_read(&policy->rwsem);
1603
1604                 cpufreq_cpu_put(policy);
1605         }
1606
1607         return ret_freq;
1608 }
1609 EXPORT_SYMBOL(cpufreq_get);
1610
1611 static struct subsys_interface cpufreq_interface = {
1612         .name           = "cpufreq",
1613         .subsys         = &cpu_subsys,
1614         .add_dev        = cpufreq_add_dev,
1615         .remove_dev     = cpufreq_remove_dev,
1616 };
1617
1618 /*
1619  * In case platform wants some specific frequency to be configured
1620  * during suspend..
1621  */
1622 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1623 {
1624         int ret;
1625
1626         if (!policy->suspend_freq) {
1627                 pr_err("%s: suspend_freq can't be zero\n", __func__);
1628                 return -EINVAL;
1629         }
1630
1631         pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1632                         policy->suspend_freq);
1633
1634         ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1635                         CPUFREQ_RELATION_H);
1636         if (ret)
1637                 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1638                                 __func__, policy->suspend_freq, ret);
1639
1640         return ret;
1641 }
1642 EXPORT_SYMBOL(cpufreq_generic_suspend);
1643
1644 /**
1645  * cpufreq_suspend() - Suspend CPUFreq governors
1646  *
1647  * Called during system wide Suspend/Hibernate cycles for suspending governors
1648  * as some platforms can't change frequency after this point in suspend cycle.
1649  * Because some of the devices (like: i2c, regulators, etc) they use for
1650  * changing frequency are suspended quickly after this point.
1651  */
1652 void cpufreq_suspend(void)
1653 {
1654         struct cpufreq_policy *policy;
1655
1656         if (!cpufreq_driver)
1657                 return;
1658
1659         if (!has_target())
1660                 return;
1661
1662         pr_debug("%s: Suspending Governors\n", __func__);
1663
1664         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1665                 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1666                         pr_err("%s: Failed to stop governor for policy: %p\n",
1667                                 __func__, policy);
1668                 else if (cpufreq_driver->suspend
1669                     && cpufreq_driver->suspend(policy))
1670                         pr_err("%s: Failed to suspend driver: %p\n", __func__,
1671                                 policy);
1672         }
1673
1674         cpufreq_suspended = true;
1675 }
1676
1677 /**
1678  * cpufreq_resume() - Resume CPUFreq governors
1679  *
1680  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1681  * are suspended with cpufreq_suspend().
1682  */
1683 void cpufreq_resume(void)
1684 {
1685         struct cpufreq_policy *policy;
1686
1687         if (!cpufreq_driver)
1688                 return;
1689
1690         if (!has_target())
1691                 return;
1692
1693         pr_debug("%s: Resuming Governors\n", __func__);
1694
1695         cpufreq_suspended = false;
1696
1697         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1698                 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1699                         pr_err("%s: Failed to resume driver: %p\n", __func__,
1700                                 policy);
1701                 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1702                     || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1703                         pr_err("%s: Failed to start governor for policy: %p\n",
1704                                 __func__, policy);
1705
1706                 /*
1707                  * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1708                  * policy in list. It will verify that the current freq is in
1709                  * sync with what we believe it to be.
1710                  */
1711                 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1712                         schedule_work(&policy->update);
1713         }
1714 }
1715
1716 /**
1717  *      cpufreq_get_current_driver - return current driver's name
1718  *
1719  *      Return the name string of the currently loaded cpufreq driver
1720  *      or NULL, if none.
1721  */
1722 const char *cpufreq_get_current_driver(void)
1723 {
1724         if (cpufreq_driver)
1725                 return cpufreq_driver->name;
1726
1727         return NULL;
1728 }
1729 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1730
1731 /*********************************************************************
1732  *                     NOTIFIER LISTS INTERFACE                      *
1733  *********************************************************************/
1734
1735 /**
1736  *      cpufreq_register_notifier - register a driver with cpufreq
1737  *      @nb: notifier function to register
1738  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1739  *
1740  *      Add a driver to one of two lists: either a list of drivers that
1741  *      are notified about clock rate changes (once before and once after
1742  *      the transition), or a list of drivers that are notified about
1743  *      changes in cpufreq policy.
1744  *
1745  *      This function may sleep, and has the same return conditions as
1746  *      blocking_notifier_chain_register.
1747  */
1748 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1749 {
1750         int ret;
1751
1752         if (cpufreq_disabled())
1753                 return -EINVAL;
1754
1755         WARN_ON(!init_cpufreq_transition_notifier_list_called);
1756
1757         switch (list) {
1758         case CPUFREQ_TRANSITION_NOTIFIER:
1759                 ret = srcu_notifier_chain_register(
1760                                 &cpufreq_transition_notifier_list, nb);
1761                 break;
1762         case CPUFREQ_POLICY_NOTIFIER:
1763                 ret = blocking_notifier_chain_register(
1764                                 &cpufreq_policy_notifier_list, nb);
1765                 break;
1766         default:
1767                 ret = -EINVAL;
1768         }
1769
1770         return ret;
1771 }
1772 EXPORT_SYMBOL(cpufreq_register_notifier);
1773
1774 /**
1775  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1776  *      @nb: notifier block to be unregistered
1777  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1778  *
1779  *      Remove a driver from the CPU frequency notifier list.
1780  *
1781  *      This function may sleep, and has the same return conditions as
1782  *      blocking_notifier_chain_unregister.
1783  */
1784 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1785 {
1786         int ret;
1787
1788         if (cpufreq_disabled())
1789                 return -EINVAL;
1790
1791         switch (list) {
1792         case CPUFREQ_TRANSITION_NOTIFIER:
1793                 ret = srcu_notifier_chain_unregister(
1794                                 &cpufreq_transition_notifier_list, nb);
1795                 break;
1796         case CPUFREQ_POLICY_NOTIFIER:
1797                 ret = blocking_notifier_chain_unregister(
1798                                 &cpufreq_policy_notifier_list, nb);
1799                 break;
1800         default:
1801                 ret = -EINVAL;
1802         }
1803
1804         return ret;
1805 }
1806 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1807
1808
1809 /*********************************************************************
1810  *                              GOVERNORS                            *
1811  *********************************************************************/
1812
1813 /* Must set freqs->new to intermediate frequency */
1814 static int __target_intermediate(struct cpufreq_policy *policy,
1815                                  struct cpufreq_freqs *freqs, int index)
1816 {
1817         int ret;
1818
1819         freqs->new = cpufreq_driver->get_intermediate(policy, index);
1820
1821         /* We don't need to switch to intermediate freq */
1822         if (!freqs->new)
1823                 return 0;
1824
1825         pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1826                  __func__, policy->cpu, freqs->old, freqs->new);
1827
1828         cpufreq_freq_transition_begin(policy, freqs);
1829         ret = cpufreq_driver->target_intermediate(policy, index);
1830         cpufreq_freq_transition_end(policy, freqs, ret);
1831
1832         if (ret)
1833                 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1834                        __func__, ret);
1835
1836         return ret;
1837 }
1838
1839 static int __target_index(struct cpufreq_policy *policy,
1840                           struct cpufreq_frequency_table *freq_table, int index)
1841 {
1842         struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1843         unsigned int intermediate_freq = 0;
1844         int retval = -EINVAL;
1845         bool notify;
1846
1847         notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1848         if (notify) {
1849                 /* Handle switching to intermediate frequency */
1850                 if (cpufreq_driver->get_intermediate) {
1851                         retval = __target_intermediate(policy, &freqs, index);
1852                         if (retval)
1853                                 return retval;
1854
1855                         intermediate_freq = freqs.new;
1856                         /* Set old freq to intermediate */
1857                         if (intermediate_freq)
1858                                 freqs.old = freqs.new;
1859                 }
1860
1861                 freqs.new = freq_table[index].frequency;
1862                 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1863                          __func__, policy->cpu, freqs.old, freqs.new);
1864
1865                 cpufreq_freq_transition_begin(policy, &freqs);
1866         }
1867
1868         retval = cpufreq_driver->target_index(policy, index);
1869         if (retval)
1870                 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1871                        retval);
1872
1873         if (notify) {
1874                 cpufreq_freq_transition_end(policy, &freqs, retval);
1875
1876                 /*
1877                  * Failed after setting to intermediate freq? Driver should have
1878                  * reverted back to initial frequency and so should we. Check
1879                  * here for intermediate_freq instead of get_intermediate, in
1880                  * case we have't switched to intermediate freq at all.
1881                  */
1882                 if (unlikely(retval && intermediate_freq)) {
1883                         freqs.old = intermediate_freq;
1884                         freqs.new = policy->restore_freq;
1885                         cpufreq_freq_transition_begin(policy, &freqs);
1886                         cpufreq_freq_transition_end(policy, &freqs, 0);
1887                 }
1888         }
1889
1890         return retval;
1891 }
1892
1893 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1894                             unsigned int target_freq,
1895                             unsigned int relation)
1896 {
1897         unsigned int old_target_freq = target_freq;
1898         int retval = -EINVAL;
1899
1900         if (cpufreq_disabled())
1901                 return -ENODEV;
1902
1903         /* Make sure that target_freq is within supported range */
1904         if (target_freq > policy->max)
1905                 target_freq = policy->max;
1906         if (target_freq < policy->min)
1907                 target_freq = policy->min;
1908
1909         pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1910                  policy->cpu, target_freq, relation, old_target_freq);
1911
1912         /*
1913          * This might look like a redundant call as we are checking it again
1914          * after finding index. But it is left intentionally for cases where
1915          * exactly same freq is called again and so we can save on few function
1916          * calls.
1917          */
1918         if (target_freq == policy->cur)
1919                 return 0;
1920
1921         /* Save last value to restore later on errors */
1922         policy->restore_freq = policy->cur;
1923
1924         if (cpufreq_driver->target)
1925                 retval = cpufreq_driver->target(policy, target_freq, relation);
1926         else if (cpufreq_driver->target_index) {
1927                 struct cpufreq_frequency_table *freq_table;
1928                 int index;
1929
1930                 freq_table = cpufreq_frequency_get_table(policy->cpu);
1931                 if (unlikely(!freq_table)) {
1932                         pr_err("%s: Unable to find freq_table\n", __func__);
1933                         goto out;
1934                 }
1935
1936                 retval = cpufreq_frequency_table_target(policy, freq_table,
1937                                 target_freq, relation, &index);
1938                 if (unlikely(retval)) {
1939                         pr_err("%s: Unable to find matching freq\n", __func__);
1940                         goto out;
1941                 }
1942
1943                 if (freq_table[index].frequency == policy->cur) {
1944                         retval = 0;
1945                         goto out;
1946                 }
1947
1948                 retval = __target_index(policy, freq_table, index);
1949         }
1950
1951 out:
1952         return retval;
1953 }
1954 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1955
1956 int cpufreq_driver_target(struct cpufreq_policy *policy,
1957                           unsigned int target_freq,
1958                           unsigned int relation)
1959 {
1960         int ret = -EINVAL;
1961
1962         down_write(&policy->rwsem);
1963
1964         ret = __cpufreq_driver_target(policy, target_freq, relation);
1965
1966         up_write(&policy->rwsem);
1967
1968         return ret;
1969 }
1970 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1971
1972 /*
1973  * when "event" is CPUFREQ_GOV_LIMITS
1974  */
1975
1976 static int __cpufreq_governor(struct cpufreq_policy *policy,
1977                                         unsigned int event)
1978 {
1979         int ret;
1980
1981         /* Only must be defined when default governor is known to have latency
1982            restrictions, like e.g. conservative or ondemand.
1983            That this is the case is already ensured in Kconfig
1984         */
1985 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1986         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1987 #else
1988         struct cpufreq_governor *gov = NULL;
1989 #endif
1990
1991         /* Don't start any governor operations if we are entering suspend */
1992         if (cpufreq_suspended)
1993                 return 0;
1994
1995         if (policy->governor->max_transition_latency &&
1996             policy->cpuinfo.transition_latency >
1997             policy->governor->max_transition_latency) {
1998                 if (!gov)
1999                         return -EINVAL;
2000                 else {
2001                         pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2002                                 policy->governor->name, gov->name);
2003                         policy->governor = gov;
2004                 }
2005         }
2006
2007         if (event == CPUFREQ_GOV_POLICY_INIT)
2008                 if (!try_module_get(policy->governor->owner))
2009                         return -EINVAL;
2010
2011         pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2012                  policy->cpu, event);
2013
2014         mutex_lock(&cpufreq_governor_lock);
2015         if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2016             || (!policy->governor_enabled
2017             && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2018                 mutex_unlock(&cpufreq_governor_lock);
2019                 return -EBUSY;
2020         }
2021
2022         if (event == CPUFREQ_GOV_STOP)
2023                 policy->governor_enabled = false;
2024         else if (event == CPUFREQ_GOV_START)
2025                 policy->governor_enabled = true;
2026
2027         mutex_unlock(&cpufreq_governor_lock);
2028
2029         ret = policy->governor->governor(policy, event);
2030
2031         if (!ret) {
2032                 if (event == CPUFREQ_GOV_POLICY_INIT)
2033                         policy->governor->initialized++;
2034                 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2035                         policy->governor->initialized--;
2036         } else {
2037                 /* Restore original values */
2038                 mutex_lock(&cpufreq_governor_lock);
2039                 if (event == CPUFREQ_GOV_STOP)
2040                         policy->governor_enabled = true;
2041                 else if (event == CPUFREQ_GOV_START)
2042                         policy->governor_enabled = false;
2043                 mutex_unlock(&cpufreq_governor_lock);
2044         }
2045
2046         if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2047                         ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2048                 module_put(policy->governor->owner);
2049
2050         return ret;
2051 }
2052
2053 int cpufreq_register_governor(struct cpufreq_governor *governor)
2054 {
2055         int err;
2056
2057         if (!governor)
2058                 return -EINVAL;
2059
2060         if (cpufreq_disabled())
2061                 return -ENODEV;
2062
2063         mutex_lock(&cpufreq_governor_mutex);
2064
2065         governor->initialized = 0;
2066         err = -EBUSY;
2067         if (__find_governor(governor->name) == NULL) {
2068                 err = 0;
2069                 list_add(&governor->governor_list, &cpufreq_governor_list);
2070         }
2071
2072         mutex_unlock(&cpufreq_governor_mutex);
2073         return err;
2074 }
2075 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2076
2077 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2078 {
2079         int cpu;
2080
2081         if (!governor)
2082                 return;
2083
2084         if (cpufreq_disabled())
2085                 return;
2086
2087         for_each_present_cpu(cpu) {
2088                 if (cpu_online(cpu))
2089                         continue;
2090                 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2091                         strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2092         }
2093
2094         mutex_lock(&cpufreq_governor_mutex);
2095         list_del(&governor->governor_list);
2096         mutex_unlock(&cpufreq_governor_mutex);
2097         return;
2098 }
2099 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2100
2101
2102 /*********************************************************************
2103  *                          POLICY INTERFACE                         *
2104  *********************************************************************/
2105
2106 /**
2107  * cpufreq_get_policy - get the current cpufreq_policy
2108  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2109  *      is written
2110  *
2111  * Reads the current cpufreq policy.
2112  */
2113 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2114 {
2115         struct cpufreq_policy *cpu_policy;
2116         if (!policy)
2117                 return -EINVAL;
2118
2119         cpu_policy = cpufreq_cpu_get(cpu);
2120         if (!cpu_policy)
2121                 return -EINVAL;
2122
2123         memcpy(policy, cpu_policy, sizeof(*policy));
2124
2125         cpufreq_cpu_put(cpu_policy);
2126         return 0;
2127 }
2128 EXPORT_SYMBOL(cpufreq_get_policy);
2129
2130 /*
2131  * policy : current policy.
2132  * new_policy: policy to be set.
2133  */
2134 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2135                                 struct cpufreq_policy *new_policy)
2136 {
2137         struct cpufreq_governor *old_gov;
2138         int ret;
2139
2140         pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2141                  new_policy->cpu, new_policy->min, new_policy->max);
2142
2143         memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2144
2145         if (new_policy->min > policy->max || new_policy->max < policy->min)
2146                 return -EINVAL;
2147
2148         /* verify the cpu speed can be set within this limit */
2149         ret = cpufreq_driver->verify(new_policy);
2150         if (ret)
2151                 return ret;
2152
2153         /* adjust if necessary - all reasons */
2154         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2155                         CPUFREQ_ADJUST, new_policy);
2156
2157         /* adjust if necessary - hardware incompatibility*/
2158         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2159                         CPUFREQ_INCOMPATIBLE, new_policy);
2160
2161         /*
2162          * verify the cpu speed can be set within this limit, which might be
2163          * different to the first one
2164          */
2165         ret = cpufreq_driver->verify(new_policy);
2166         if (ret)
2167                 return ret;
2168
2169         /* notification of the new policy */
2170         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2171                         CPUFREQ_NOTIFY, new_policy);
2172
2173         policy->min = new_policy->min;
2174         policy->max = new_policy->max;
2175
2176         pr_debug("new min and max freqs are %u - %u kHz\n",
2177                  policy->min, policy->max);
2178
2179         if (cpufreq_driver->setpolicy) {
2180                 policy->policy = new_policy->policy;
2181                 pr_debug("setting range\n");
2182                 return cpufreq_driver->setpolicy(new_policy);
2183         }
2184
2185         if (new_policy->governor == policy->governor)
2186                 goto out;
2187
2188         pr_debug("governor switch\n");
2189
2190         /* save old, working values */
2191         old_gov = policy->governor;
2192         /* end old governor */
2193         if (old_gov) {
2194                 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2195                 up_write(&policy->rwsem);
2196                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2197                 down_write(&policy->rwsem);
2198         }
2199
2200         /* start new governor */
2201         policy->governor = new_policy->governor;
2202         if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2203                 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2204                         goto out;
2205
2206                 up_write(&policy->rwsem);
2207                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2208                 down_write(&policy->rwsem);
2209         }
2210
2211         /* new governor failed, so re-start old one */
2212         pr_debug("starting governor %s failed\n", policy->governor->name);
2213         if (old_gov) {
2214                 policy->governor = old_gov;
2215                 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2216                 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2217         }
2218
2219         return -EINVAL;
2220
2221  out:
2222         pr_debug("governor: change or update limits\n");
2223         return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2224 }
2225
2226 /**
2227  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
2228  *      @cpu: CPU which shall be re-evaluated
2229  *
2230  *      Useful for policy notifiers which have different necessities
2231  *      at different times.
2232  */
2233 int cpufreq_update_policy(unsigned int cpu)
2234 {
2235         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2236         struct cpufreq_policy new_policy;
2237         int ret;
2238
2239         if (!policy)
2240                 return -ENODEV;
2241
2242         down_write(&policy->rwsem);
2243
2244         pr_debug("updating policy for CPU %u\n", cpu);
2245         memcpy(&new_policy, policy, sizeof(*policy));
2246         new_policy.min = policy->user_policy.min;
2247         new_policy.max = policy->user_policy.max;
2248         new_policy.policy = policy->user_policy.policy;
2249         new_policy.governor = policy->user_policy.governor;
2250
2251         /*
2252          * BIOS might change freq behind our back
2253          * -> ask driver for current freq and notify governors about a change
2254          */
2255         if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2256                 new_policy.cur = cpufreq_driver->get(cpu);
2257                 if (WARN_ON(!new_policy.cur)) {
2258                         ret = -EIO;
2259                         goto unlock;
2260                 }
2261
2262                 if (!policy->cur) {
2263                         pr_debug("Driver did not initialize current freq\n");
2264                         policy->cur = new_policy.cur;
2265                 } else {
2266                         if (policy->cur != new_policy.cur && has_target())
2267                                 cpufreq_out_of_sync(cpu, policy->cur,
2268                                                                 new_policy.cur);
2269                 }
2270         }
2271
2272         ret = cpufreq_set_policy(policy, &new_policy);
2273
2274 unlock:
2275         up_write(&policy->rwsem);
2276
2277         cpufreq_cpu_put(policy);
2278         return ret;
2279 }
2280 EXPORT_SYMBOL(cpufreq_update_policy);
2281
2282 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2283                                         unsigned long action, void *hcpu)
2284 {
2285         unsigned int cpu = (unsigned long)hcpu;
2286         struct device *dev;
2287
2288         dev = get_cpu_device(cpu);
2289         if (dev) {
2290                 switch (action & ~CPU_TASKS_FROZEN) {
2291                 case CPU_ONLINE:
2292                         __cpufreq_add_dev(dev, NULL);
2293                         break;
2294
2295                 case CPU_DOWN_PREPARE:
2296                         __cpufreq_remove_dev_prepare(dev, NULL);
2297                         break;
2298
2299                 case CPU_POST_DEAD:
2300                         __cpufreq_remove_dev_finish(dev, NULL);
2301                         break;
2302
2303                 case CPU_DOWN_FAILED:
2304                         __cpufreq_add_dev(dev, NULL);
2305                         break;
2306                 }
2307         }
2308         return NOTIFY_OK;
2309 }
2310
2311 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2312         .notifier_call = cpufreq_cpu_callback,
2313 };
2314
2315 /*********************************************************************
2316  *               BOOST                                               *
2317  *********************************************************************/
2318 static int cpufreq_boost_set_sw(int state)
2319 {
2320         struct cpufreq_frequency_table *freq_table;
2321         struct cpufreq_policy *policy;
2322         int ret = -EINVAL;
2323
2324         list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2325                 freq_table = cpufreq_frequency_get_table(policy->cpu);
2326                 if (freq_table) {
2327                         ret = cpufreq_frequency_table_cpuinfo(policy,
2328                                                         freq_table);
2329                         if (ret) {
2330                                 pr_err("%s: Policy frequency update failed\n",
2331                                        __func__);
2332                                 break;
2333                         }
2334                         policy->user_policy.max = policy->max;
2335                         __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2336                 }
2337         }
2338
2339         return ret;
2340 }
2341
2342 int cpufreq_boost_trigger_state(int state)
2343 {
2344         unsigned long flags;
2345         int ret = 0;
2346
2347         if (cpufreq_driver->boost_enabled == state)
2348                 return 0;
2349
2350         write_lock_irqsave(&cpufreq_driver_lock, flags);
2351         cpufreq_driver->boost_enabled = state;
2352         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2353
2354         ret = cpufreq_driver->set_boost(state);
2355         if (ret) {
2356                 write_lock_irqsave(&cpufreq_driver_lock, flags);
2357                 cpufreq_driver->boost_enabled = !state;
2358                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2359
2360                 pr_err("%s: Cannot %s BOOST\n",
2361                        __func__, state ? "enable" : "disable");
2362         }
2363
2364         return ret;
2365 }
2366
2367 int cpufreq_boost_supported(void)
2368 {
2369         if (likely(cpufreq_driver))
2370                 return cpufreq_driver->boost_supported;
2371
2372         return 0;
2373 }
2374 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2375
2376 int cpufreq_boost_enabled(void)
2377 {
2378         return cpufreq_driver->boost_enabled;
2379 }
2380 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2381
2382 /*********************************************************************
2383  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2384  *********************************************************************/
2385
2386 /**
2387  * cpufreq_register_driver - register a CPU Frequency driver
2388  * @driver_data: A struct cpufreq_driver containing the values#
2389  * submitted by the CPU Frequency driver.
2390  *
2391  * Registers a CPU Frequency driver to this core code. This code
2392  * returns zero on success, -EBUSY when another driver got here first
2393  * (and isn't unregistered in the meantime).
2394  *
2395  */
2396 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2397 {
2398         unsigned long flags;
2399         int ret;
2400
2401         if (cpufreq_disabled())
2402                 return -ENODEV;
2403
2404         if (!driver_data || !driver_data->verify || !driver_data->init ||
2405             !(driver_data->setpolicy || driver_data->target_index ||
2406                     driver_data->target) ||
2407              (driver_data->setpolicy && (driver_data->target_index ||
2408                     driver_data->target)) ||
2409              (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2410                 return -EINVAL;
2411
2412         pr_debug("trying to register driver %s\n", driver_data->name);
2413
2414         if (driver_data->setpolicy)
2415                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2416
2417         write_lock_irqsave(&cpufreq_driver_lock, flags);
2418         if (cpufreq_driver) {
2419                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2420                 return -EEXIST;
2421         }
2422         cpufreq_driver = driver_data;
2423         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2424
2425         if (cpufreq_boost_supported()) {
2426                 /*
2427                  * Check if driver provides function to enable boost -
2428                  * if not, use cpufreq_boost_set_sw as default
2429                  */
2430                 if (!cpufreq_driver->set_boost)
2431                         cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2432
2433                 ret = cpufreq_sysfs_create_file(&boost.attr);
2434                 if (ret) {
2435                         pr_err("%s: cannot register global BOOST sysfs file\n",
2436                                __func__);
2437                         goto err_null_driver;
2438                 }
2439         }
2440
2441         ret = subsys_interface_register(&cpufreq_interface);
2442         if (ret)
2443                 goto err_boost_unreg;
2444
2445         if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2446                 int i;
2447                 ret = -ENODEV;
2448
2449                 /* check for at least one working CPU */
2450                 for (i = 0; i < nr_cpu_ids; i++)
2451                         if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2452                                 ret = 0;
2453                                 break;
2454                         }
2455
2456                 /* if all ->init() calls failed, unregister */
2457                 if (ret) {
2458                         pr_debug("no CPU initialized for driver %s\n",
2459                                  driver_data->name);
2460                         goto err_if_unreg;
2461                 }
2462         }
2463
2464         register_hotcpu_notifier(&cpufreq_cpu_notifier);
2465         pr_debug("driver %s up and running\n", driver_data->name);
2466
2467         return 0;
2468 err_if_unreg:
2469         subsys_interface_unregister(&cpufreq_interface);
2470 err_boost_unreg:
2471         if (cpufreq_boost_supported())
2472                 cpufreq_sysfs_remove_file(&boost.attr);
2473 err_null_driver:
2474         write_lock_irqsave(&cpufreq_driver_lock, flags);
2475         cpufreq_driver = NULL;
2476         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2477         return ret;
2478 }
2479 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2480
2481 /**
2482  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2483  *
2484  * Unregister the current CPUFreq driver. Only call this if you have
2485  * the right to do so, i.e. if you have succeeded in initialising before!
2486  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2487  * currently not initialised.
2488  */
2489 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2490 {
2491         unsigned long flags;
2492
2493         if (!cpufreq_driver || (driver != cpufreq_driver))
2494                 return -EINVAL;
2495
2496         pr_debug("unregistering driver %s\n", driver->name);
2497
2498         subsys_interface_unregister(&cpufreq_interface);
2499         if (cpufreq_boost_supported())
2500                 cpufreq_sysfs_remove_file(&boost.attr);
2501
2502         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2503
2504         down_write(&cpufreq_rwsem);
2505         write_lock_irqsave(&cpufreq_driver_lock, flags);
2506
2507         cpufreq_driver = NULL;
2508
2509         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2510         up_write(&cpufreq_rwsem);
2511
2512         return 0;
2513 }
2514 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2515
2516 static int __init cpufreq_core_init(void)
2517 {
2518         if (cpufreq_disabled())
2519                 return -ENODEV;
2520
2521         cpufreq_global_kobject = kobject_create();
2522         BUG_ON(!cpufreq_global_kobject);
2523
2524         return 0;
2525 }
2526 core_initcall(cpufreq_core_init);