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