drivers/cpufreq/cpufreq.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
has_target
cpufreq_disabled
disable_cpufreq
have_governor_per_policy
get_governor_parent_kobj
get_cpu_idle_time_jiffy
get_cpu_idle_time
arch_set_freq_scale
cpufreq_generic_init
cpufreq_cpu_get_raw
cpufreq_generic_get
cpufreq_cpu_get
cpufreq_cpu_put
cpufreq_cpu_release
cpufreq_cpu_acquire
adjust_jiffies
cpufreq_notify_transition
cpufreq_notify_post_transition
cpufreq_freq_transition_begin
cpufreq_freq_transition_end
cpufreq_list_transition_notifiers
cpufreq_enable_fast_switch
cpufreq_disable_fast_switch
cpufreq_driver_resolve_freq
cpufreq_policy_transition_delay_us
show_boost
store_boost
find_governor
cpufreq_parse_policy
cpufreq_parse_governor
arch_freq_get_on_cpu
show_scaling_cur_freq
show_cpuinfo_cur_freq
show_scaling_governor
store_scaling_governor
show_scaling_driver
show_scaling_available_governors
cpufreq_show_cpus
show_related_cpus
show_affected_cpus
store_scaling_setspeed
show_scaling_setspeed
show_bios_limit
show
store
cpufreq_sysfs_release
add_cpu_dev_symlink
remove_cpu_dev_symlink
cpufreq_add_dev_interface
cpufreq_default_governor
cpufreq_init_policy
cpufreq_add_policy_cpu
refresh_frequency_limits
handle_update
cpufreq_notifier_min
cpufreq_notifier_max
cpufreq_policy_put_kobj
cpufreq_policy_alloc
cpufreq_policy_free
cpufreq_online
cpufreq_add_dev
cpufreq_offline
cpufreq_remove_dev
cpufreq_out_of_sync
cpufreq_verify_current_freq
cpufreq_quick_get
cpufreq_quick_get_max
__cpufreq_get
cpufreq_get
cpufreq_generic_suspend
cpufreq_suspend
cpufreq_resume
cpufreq_get_current_driver
cpufreq_get_driver_data
cpufreq_register_notifier
cpufreq_unregister_notifier
cpufreq_driver_fast_switch
__target_intermediate
__target_index
__cpufreq_driver_target
cpufreq_driver_target
cpufreq_fallback_governor
cpufreq_init_governor
cpufreq_exit_governor
cpufreq_start_governor
cpufreq_stop_governor
cpufreq_governor_limits
cpufreq_register_governor
cpufreq_unregister_governor
cpufreq_get_policy
cpufreq_set_policy
cpufreq_update_policy
cpufreq_update_limits
cpufreq_boost_set_sw
cpufreq_boost_trigger_state
cpufreq_boost_supported
create_boost_sysfs_file
remove_boost_sysfs_file
cpufreq_enable_boost_support
cpufreq_boost_enabled
cpuhp_cpufreq_online
cpuhp_cpufreq_offline
cpufreq_register_driver
cpufreq_unregister_driver
cpufreq_core_init
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/drivers/cpufreq/cpufreq.c
   4  *
   5  *  Copyright (C) 2001 Russell King
   6  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
   7  *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
   8  *
   9  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
  10  *      Added handling for CPU hotplug
  11  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
  12  *      Fix handling for CPU hotplug -- affected CPUs
  13  */
  14 
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16 
  17 #include <linux/cpu.h>
  18 #include <linux/cpufreq.h>
  19 #include <linux/cpu_cooling.h>
  20 #include <linux/delay.h>
  21 #include <linux/device.h>
  22 #include <linux/init.h>
  23 #include <linux/kernel_stat.h>
  24 #include <linux/module.h>
  25 #include <linux/mutex.h>
  26 #include <linux/pm_qos.h>
  27 #include <linux/slab.h>
  28 #include <linux/suspend.h>
  29 #include <linux/syscore_ops.h>
  30 #include <linux/tick.h>
  31 #include <trace/events/power.h>
  32 
  33 static LIST_HEAD(cpufreq_policy_list);
  34 
  35 /* Macros to iterate over CPU policies */
  36 #define for_each_suitable_policy(__policy, __active)                     \
  37         list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
  38                 if ((__active) == !policy_is_inactive(__policy))
  39 
  40 #define for_each_active_policy(__policy)                \
  41         for_each_suitable_policy(__policy, true)
  42 #define for_each_inactive_policy(__policy)              \
  43         for_each_suitable_policy(__policy, false)
  44 
  45 #define for_each_policy(__policy)                       \
  46         list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
  47 
  48 /* Iterate over governors */
  49 static LIST_HEAD(cpufreq_governor_list);
  50 #define for_each_governor(__governor)                           \
  51         list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
  52 
  53 /**
  54  * The "cpufreq driver" - the arch- or hardware-dependent low
  55  * level driver of CPUFreq support, and its spinlock. This lock
  56  * also protects the cpufreq_cpu_data array.
  57  */
  58 static struct cpufreq_driver *cpufreq_driver;
  59 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
  60 static DEFINE_RWLOCK(cpufreq_driver_lock);
  61 
  62 /* Flag to suspend/resume CPUFreq governors */
  63 static bool cpufreq_suspended;
  64 
  65 static inline bool has_target(void)
  66 {
  67         return cpufreq_driver->target_index || cpufreq_driver->target;
  68 }
  69 
  70 /* internal prototypes */
  71 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
  72 static int cpufreq_init_governor(struct cpufreq_policy *policy);
  73 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
  74 static int cpufreq_start_governor(struct cpufreq_policy *policy);
  75 static void cpufreq_stop_governor(struct cpufreq_policy *policy);
  76 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
  77 static int cpufreq_set_policy(struct cpufreq_policy *policy,
  78                               struct cpufreq_governor *new_gov,
  79                               unsigned int new_pol);
  80 
  81 /**
  82  * Two notifier lists: the "policy" list is involved in the
  83  * validation process for a new CPU frequency policy; the
  84  * "transition" list for kernel code that needs to handle
  85  * changes to devices when the CPU clock speed changes.
  86  * The mutex locks both lists.
  87  */
  88 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
  89 SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
  90 
  91 static int off __read_mostly;
  92 static int cpufreq_disabled(void)
  93 {
  94         return off;
  95 }
  96 void disable_cpufreq(void)
  97 {
  98         off = 1;
  99 }
 100 static DEFINE_MUTEX(cpufreq_governor_mutex);
 101 
 102 bool have_governor_per_policy(void)
 103 {
 104         return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
 105 }
 106 EXPORT_SYMBOL_GPL(have_governor_per_policy);
 107 
 108 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
 109 {
 110         if (have_governor_per_policy())
 111                 return &policy->kobj;
 112         else
 113                 return cpufreq_global_kobject;
 114 }
 115 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
 116 
 117 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
 118 {
 119         u64 idle_time;
 120         u64 cur_wall_time;
 121         u64 busy_time;
 122 
 123         cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
 124 
 125         busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
 126         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
 127         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
 128         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
 129         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
 130         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
 131 
 132         idle_time = cur_wall_time - busy_time;
 133         if (wall)
 134                 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
 135 
 136         return div_u64(idle_time, NSEC_PER_USEC);
 137 }
 138 
 139 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
 140 {
 141         u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
 142 
 143         if (idle_time == -1ULL)
 144                 return get_cpu_idle_time_jiffy(cpu, wall);
 145         else if (!io_busy)
 146                 idle_time += get_cpu_iowait_time_us(cpu, wall);
 147 
 148         return idle_time;
 149 }
 150 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
 151 
 152 __weak void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
 153                 unsigned long max_freq)
 154 {
 155 }
 156 EXPORT_SYMBOL_GPL(arch_set_freq_scale);
 157 
 158 /*
 159  * This is a generic cpufreq init() routine which can be used by cpufreq
 160  * drivers of SMP systems. It will do following:
 161  * - validate & show freq table passed
 162  * - set policies transition latency
 163  * - policy->cpus with all possible CPUs
 164  */
 165 void cpufreq_generic_init(struct cpufreq_policy *policy,
 166                 struct cpufreq_frequency_table *table,
 167                 unsigned int transition_latency)
 168 {
 169         policy->freq_table = table;
 170         policy->cpuinfo.transition_latency = transition_latency;
 171 
 172         /*
 173          * The driver only supports the SMP configuration where all processors
 174          * share the clock and voltage and clock.
 175          */
 176         cpumask_setall(policy->cpus);
 177 }
 178 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
 179 
 180 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
 181 {
 182         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
 183 
 184         return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
 185 }
 186 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
 187 
 188 unsigned int cpufreq_generic_get(unsigned int cpu)
 189 {
 190         struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
 191 
 192         if (!policy || IS_ERR(policy->clk)) {
 193                 pr_err("%s: No %s associated to cpu: %d\n",
 194                        __func__, policy ? "clk" : "policy", cpu);
 195                 return 0;
 196         }
 197 
 198         return clk_get_rate(policy->clk) / 1000;
 199 }
 200 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
 201 
 202 /**
 203  * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
 204  * @cpu: CPU to find the policy for.
 205  *
 206  * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
 207  * the kobject reference counter of that policy.  Return a valid policy on
 208  * success or NULL on failure.
 209  *
 210  * The policy returned by this function has to be released with the help of
 211  * cpufreq_cpu_put() to balance its kobject reference counter properly.
 212  */
 213 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 214 {
 215         struct cpufreq_policy *policy = NULL;
 216         unsigned long flags;
 217 
 218         if (WARN_ON(cpu >= nr_cpu_ids))
 219                 return NULL;
 220 
 221         /* get the cpufreq driver */
 222         read_lock_irqsave(&cpufreq_driver_lock, flags);
 223 
 224         if (cpufreq_driver) {
 225                 /* get the CPU */
 226                 policy = cpufreq_cpu_get_raw(cpu);
 227                 if (policy)
 228                         kobject_get(&policy->kobj);
 229         }
 230 
 231         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
 232 
 233         return policy;
 234 }
 235 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
 236 
 237 /**
 238  * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
 239  * @policy: cpufreq policy returned by cpufreq_cpu_get().
 240  */
 241 void cpufreq_cpu_put(struct cpufreq_policy *policy)
 242 {
 243         kobject_put(&policy->kobj);
 244 }
 245 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 246 
 247 /**
 248  * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
 249  * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
 250  */
 251 void cpufreq_cpu_release(struct cpufreq_policy *policy)
 252 {
 253         if (WARN_ON(!policy))
 254                 return;
 255 
 256         lockdep_assert_held(&policy->rwsem);
 257 
 258         up_write(&policy->rwsem);
 259 
 260         cpufreq_cpu_put(policy);
 261 }
 262 
 263 /**
 264  * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
 265  * @cpu: CPU to find the policy for.
 266  *
 267  * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
 268  * if the policy returned by it is not NULL, acquire its rwsem for writing.
 269  * Return the policy if it is active or release it and return NULL otherwise.
 270  *
 271  * The policy returned by this function has to be released with the help of
 272  * cpufreq_cpu_release() in order to release its rwsem and balance its usage
 273  * counter properly.
 274  */
 275 struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
 276 {
 277         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 278 
 279         if (!policy)
 280                 return NULL;
 281 
 282         down_write(&policy->rwsem);
 283 
 284         if (policy_is_inactive(policy)) {
 285                 cpufreq_cpu_release(policy);
 286                 return NULL;
 287         }
 288 
 289         return policy;
 290 }
 291 
 292 /*********************************************************************
 293  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 294  *********************************************************************/
 295 
 296 /**
 297  * adjust_jiffies - adjust the system "loops_per_jiffy"
 298  *
 299  * This function alters the system "loops_per_jiffy" for the clock
 300  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 301  * systems as each CPU might be scaled differently. So, use the arch
 302  * per-CPU loops_per_jiffy value wherever possible.
 303  */
 304 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 305 {
 306 #ifndef CONFIG_SMP
 307         static unsigned long l_p_j_ref;
 308         static unsigned int l_p_j_ref_freq;
 309 
 310         if (ci->flags & CPUFREQ_CONST_LOOPS)
 311                 return;
 312 
 313         if (!l_p_j_ref_freq) {
 314                 l_p_j_ref = loops_per_jiffy;
 315                 l_p_j_ref_freq = ci->old;
 316                 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
 317                          l_p_j_ref, l_p_j_ref_freq);
 318         }
 319         if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
 320                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
 321                                                                 ci->new);
 322                 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
 323                          loops_per_jiffy, ci->new);
 324         }
 325 #endif
 326 }
 327 
 328 /**
 329  * cpufreq_notify_transition - Notify frequency transition and adjust_jiffies.
 330  * @policy: cpufreq policy to enable fast frequency switching for.
 331  * @freqs: contain details of the frequency update.
 332  * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
 333  *
 334  * This function calls the transition notifiers and the "adjust_jiffies"
 335  * function. It is called twice on all CPU frequency changes that have
 336  * external effects.
 337  */
 338 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
 339                                       struct cpufreq_freqs *freqs,
 340                                       unsigned int state)
 341 {
 342         int cpu;
 343 
 344         BUG_ON(irqs_disabled());
 345 
 346         if (cpufreq_disabled())
 347                 return;
 348 
 349         freqs->policy = policy;
 350         freqs->flags = cpufreq_driver->flags;
 351         pr_debug("notification %u of frequency transition to %u kHz\n",
 352                  state, freqs->new);
 353 
 354         switch (state) {
 355         case CPUFREQ_PRECHANGE:
 356                 /*
 357                  * Detect if the driver reported a value as "old frequency"
 358                  * which is not equal to what the cpufreq core thinks is
 359                  * "old frequency".
 360                  */
 361                 if (policy->cur && policy->cur != freqs->old) {
 362                         pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
 363                                  freqs->old, policy->cur);
 364                         freqs->old = policy->cur;
 365                 }
 366 
 367                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 368                                          CPUFREQ_PRECHANGE, freqs);
 369 
 370                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 371                 break;
 372 
 373         case CPUFREQ_POSTCHANGE:
 374                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 375                 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
 376                          cpumask_pr_args(policy->cpus));
 377 
 378                 for_each_cpu(cpu, policy->cpus)
 379                         trace_cpu_frequency(freqs->new, cpu);
 380 
 381                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 382                                          CPUFREQ_POSTCHANGE, freqs);
 383 
 384                 cpufreq_stats_record_transition(policy, freqs->new);
 385                 policy->cur = freqs->new;
 386         }
 387 }
 388 
 389 /* Do post notifications when there are chances that transition has failed */
 390 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
 391                 struct cpufreq_freqs *freqs, int transition_failed)
 392 {
 393         cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
 394         if (!transition_failed)
 395                 return;
 396 
 397         swap(freqs->old, freqs->new);
 398         cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
 399         cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
 400 }
 401 
 402 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
 403                 struct cpufreq_freqs *freqs)
 404 {
 405 
 406         /*
 407          * Catch double invocations of _begin() which lead to self-deadlock.
 408          * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
 409          * doesn't invoke _begin() on their behalf, and hence the chances of
 410          * double invocations are very low. Moreover, there are scenarios
 411          * where these checks can emit false-positive warnings in these
 412          * drivers; so we avoid that by skipping them altogether.
 413          */
 414         WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
 415                                 && current == policy->transition_task);
 416 
 417 wait:
 418         wait_event(policy->transition_wait, !policy->transition_ongoing);
 419 
 420         spin_lock(&policy->transition_lock);
 421 
 422         if (unlikely(policy->transition_ongoing)) {
 423                 spin_unlock(&policy->transition_lock);
 424                 goto wait;
 425         }
 426 
 427         policy->transition_ongoing = true;
 428         policy->transition_task = current;
 429 
 430         spin_unlock(&policy->transition_lock);
 431 
 432         cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
 433 }
 434 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
 435 
 436 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
 437                 struct cpufreq_freqs *freqs, int transition_failed)
 438 {
 439         if (WARN_ON(!policy->transition_ongoing))
 440                 return;
 441 
 442         cpufreq_notify_post_transition(policy, freqs, transition_failed);
 443 
 444         policy->transition_ongoing = false;
 445         policy->transition_task = NULL;
 446 
 447         wake_up(&policy->transition_wait);
 448 }
 449 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
 450 
 451 /*
 452  * Fast frequency switching status count.  Positive means "enabled", negative
 453  * means "disabled" and 0 means "not decided yet".
 454  */
 455 static int cpufreq_fast_switch_count;
 456 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
 457 
 458 static void cpufreq_list_transition_notifiers(void)
 459 {
 460         struct notifier_block *nb;
 461 
 462         pr_info("Registered transition notifiers:\n");
 463 
 464         mutex_lock(&cpufreq_transition_notifier_list.mutex);
 465 
 466         for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
 467                 pr_info("%pS\n", nb->notifier_call);
 468 
 469         mutex_unlock(&cpufreq_transition_notifier_list.mutex);
 470 }
 471 
 472 /**
 473  * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
 474  * @policy: cpufreq policy to enable fast frequency switching for.
 475  *
 476  * Try to enable fast frequency switching for @policy.
 477  *
 478  * The attempt will fail if there is at least one transition notifier registered
 479  * at this point, as fast frequency switching is quite fundamentally at odds
 480  * with transition notifiers.  Thus if successful, it will make registration of
 481  * transition notifiers fail going forward.
 482  */
 483 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
 484 {
 485         lockdep_assert_held(&policy->rwsem);
 486 
 487         if (!policy->fast_switch_possible)
 488                 return;
 489 
 490         mutex_lock(&cpufreq_fast_switch_lock);
 491         if (cpufreq_fast_switch_count >= 0) {
 492                 cpufreq_fast_switch_count++;
 493                 policy->fast_switch_enabled = true;
 494         } else {
 495                 pr_warn("CPU%u: Fast frequency switching not enabled\n",
 496                         policy->cpu);
 497                 cpufreq_list_transition_notifiers();
 498         }
 499         mutex_unlock(&cpufreq_fast_switch_lock);
 500 }
 501 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
 502 
 503 /**
 504  * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
 505  * @policy: cpufreq policy to disable fast frequency switching for.
 506  */
 507 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
 508 {
 509         mutex_lock(&cpufreq_fast_switch_lock);
 510         if (policy->fast_switch_enabled) {
 511                 policy->fast_switch_enabled = false;
 512                 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
 513                         cpufreq_fast_switch_count--;
 514         }
 515         mutex_unlock(&cpufreq_fast_switch_lock);
 516 }
 517 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
 518 
 519 /**
 520  * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
 521  * one.
 522  * @target_freq: target frequency to resolve.
 523  *
 524  * The target to driver frequency mapping is cached in the policy.
 525  *
 526  * Return: Lowest driver-supported frequency greater than or equal to the
 527  * given target_freq, subject to policy (min/max) and driver limitations.
 528  */
 529 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
 530                                          unsigned int target_freq)
 531 {
 532         target_freq = clamp_val(target_freq, policy->min, policy->max);
 533         policy->cached_target_freq = target_freq;
 534 
 535         if (cpufreq_driver->target_index) {
 536                 int idx;
 537 
 538                 idx = cpufreq_frequency_table_target(policy, target_freq,
 539                                                      CPUFREQ_RELATION_L);
 540                 policy->cached_resolved_idx = idx;
 541                 return policy->freq_table[idx].frequency;
 542         }
 543 
 544         if (cpufreq_driver->resolve_freq)
 545                 return cpufreq_driver->resolve_freq(policy, target_freq);
 546 
 547         return target_freq;
 548 }
 549 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
 550 
 551 unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
 552 {
 553         unsigned int latency;
 554 
 555         if (policy->transition_delay_us)
 556                 return policy->transition_delay_us;
 557 
 558         latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
 559         if (latency) {
 560                 /*
 561                  * For platforms that can change the frequency very fast (< 10
 562                  * us), the above formula gives a decent transition delay. But
 563                  * for platforms where transition_latency is in milliseconds, it
 564                  * ends up giving unrealistic values.
 565                  *
 566                  * Cap the default transition delay to 10 ms, which seems to be
 567                  * a reasonable amount of time after which we should reevaluate
 568                  * the frequency.
 569                  */
 570                 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
 571         }
 572 
 573         return LATENCY_MULTIPLIER;
 574 }
 575 EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
 576 
 577 /*********************************************************************
 578  *                          SYSFS INTERFACE                          *
 579  *********************************************************************/
 580 static ssize_t show_boost(struct kobject *kobj,
 581                           struct kobj_attribute *attr, char *buf)
 582 {
 583         return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
 584 }
 585 
 586 static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
 587                            const char *buf, size_t count)
 588 {
 589         int ret, enable;
 590 
 591         ret = sscanf(buf, "%d", &enable);
 592         if (ret != 1 || enable < 0 || enable > 1)
 593                 return -EINVAL;
 594 
 595         if (cpufreq_boost_trigger_state(enable)) {
 596                 pr_err("%s: Cannot %s BOOST!\n",
 597                        __func__, enable ? "enable" : "disable");
 598                 return -EINVAL;
 599         }
 600 
 601         pr_debug("%s: cpufreq BOOST %s\n",
 602                  __func__, enable ? "enabled" : "disabled");
 603 
 604         return count;
 605 }
 606 define_one_global_rw(boost);
 607 
 608 static struct cpufreq_governor *find_governor(const char *str_governor)
 609 {
 610         struct cpufreq_governor *t;
 611 
 612         for_each_governor(t)
 613                 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
 614                         return t;
 615 
 616         return NULL;
 617 }
 618 
 619 static unsigned int cpufreq_parse_policy(char *str_governor)
 620 {
 621         if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
 622                 return CPUFREQ_POLICY_PERFORMANCE;
 623 
 624         if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
 625                 return CPUFREQ_POLICY_POWERSAVE;
 626 
 627         return CPUFREQ_POLICY_UNKNOWN;
 628 }
 629 
 630 /**
 631  * cpufreq_parse_governor - parse a governor string only for has_target()
 632  * @str_governor: Governor name.
 633  */
 634 static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
 635 {
 636         struct cpufreq_governor *t;
 637 
 638         mutex_lock(&cpufreq_governor_mutex);
 639 
 640         t = find_governor(str_governor);
 641         if (!t) {
 642                 int ret;
 643 
 644                 mutex_unlock(&cpufreq_governor_mutex);
 645 
 646                 ret = request_module("cpufreq_%s", str_governor);
 647                 if (ret)
 648                         return NULL;
 649 
 650                 mutex_lock(&cpufreq_governor_mutex);
 651 
 652                 t = find_governor(str_governor);
 653         }
 654         if (t && !try_module_get(t->owner))
 655                 t = NULL;
 656 
 657         mutex_unlock(&cpufreq_governor_mutex);
 658 
 659         return t;
 660 }
 661 
 662 /**
 663  * cpufreq_per_cpu_attr_read() / show_##file_name() -
 664  * print out cpufreq information
 665  *
 666  * Write out information from cpufreq_driver->policy[cpu]; object must be
 667  * "unsigned int".
 668  */
 669 
 670 #define show_one(file_name, object)                     \
 671 static ssize_t show_##file_name                         \
 672 (struct cpufreq_policy *policy, char *buf)              \
 673 {                                                       \
 674         return sprintf(buf, "%u\n", policy->object);    \
 675 }
 676 
 677 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 678 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 679 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
 680 show_one(scaling_min_freq, min);
 681 show_one(scaling_max_freq, max);
 682 
 683 __weak unsigned int arch_freq_get_on_cpu(int cpu)
 684 {
 685         return 0;
 686 }
 687 
 688 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
 689 {
 690         ssize_t ret;
 691         unsigned int freq;
 692 
 693         freq = arch_freq_get_on_cpu(policy->cpu);
 694         if (freq)
 695                 ret = sprintf(buf, "%u\n", freq);
 696         else if (cpufreq_driver && cpufreq_driver->setpolicy &&
 697                         cpufreq_driver->get)
 698                 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
 699         else
 700                 ret = sprintf(buf, "%u\n", policy->cur);
 701         return ret;
 702 }
 703 
 704 /**
 705  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 706  */
 707 #define store_one(file_name, object)                    \
 708 static ssize_t store_##file_name                                        \
 709 (struct cpufreq_policy *policy, const char *buf, size_t count)          \
 710 {                                                                       \
 711         unsigned long val;                                              \
 712         int ret;                                                        \
 713                                                                         \
 714         ret = sscanf(buf, "%lu", &val);                                 \
 715         if (ret != 1)                                                   \
 716                 return -EINVAL;                                         \
 717                                                                         \
 718         ret = freq_qos_update_request(policy->object##_freq_req, val);\
 719         return ret >= 0 ? count : ret;                                  \
 720 }
 721 
 722 store_one(scaling_min_freq, min);
 723 store_one(scaling_max_freq, max);
 724 
 725 /**
 726  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 727  */
 728 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
 729                                         char *buf)
 730 {
 731         unsigned int cur_freq = __cpufreq_get(policy);
 732 
 733         if (cur_freq)
 734                 return sprintf(buf, "%u\n", cur_freq);
 735 
 736         return sprintf(buf, "<unknown>\n");
 737 }
 738 
 739 /**
 740  * show_scaling_governor - show the current policy for the specified CPU
 741  */
 742 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 743 {
 744         if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
 745                 return sprintf(buf, "powersave\n");
 746         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 747                 return sprintf(buf, "performance\n");
 748         else if (policy->governor)
 749                 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
 750                                 policy->governor->name);
 751         return -EINVAL;
 752 }
 753 
 754 /**
 755  * store_scaling_governor - store policy for the specified CPU
 756  */
 757 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 758                                         const char *buf, size_t count)
 759 {
 760         char str_governor[16];
 761         int ret;
 762 
 763         ret = sscanf(buf, "%15s", str_governor);
 764         if (ret != 1)
 765                 return -EINVAL;
 766 
 767         if (cpufreq_driver->setpolicy) {
 768                 unsigned int new_pol;
 769 
 770                 new_pol = cpufreq_parse_policy(str_governor);
 771                 if (!new_pol)
 772                         return -EINVAL;
 773 
 774                 ret = cpufreq_set_policy(policy, NULL, new_pol);
 775         } else {
 776                 struct cpufreq_governor *new_gov;
 777 
 778                 new_gov = cpufreq_parse_governor(str_governor);
 779                 if (!new_gov)
 780                         return -EINVAL;
 781 
 782                 ret = cpufreq_set_policy(policy, new_gov,
 783                                          CPUFREQ_POLICY_UNKNOWN);
 784 
 785                 module_put(new_gov->owner);
 786         }
 787 
 788         return ret ? ret : count;
 789 }
 790 
 791 /**
 792  * show_scaling_driver - show the cpufreq driver currently loaded
 793  */
 794 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
 795 {
 796         return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
 797 }
 798 
 799 /**
 800  * show_scaling_available_governors - show the available CPUfreq governors
 801  */
 802 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
 803                                                 char *buf)
 804 {
 805         ssize_t i = 0;
 806         struct cpufreq_governor *t;
 807 
 808         if (!has_target()) {
 809                 i += sprintf(buf, "performance powersave");
 810                 goto out;
 811         }
 812 
 813         for_each_governor(t) {
 814                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
 815                     - (CPUFREQ_NAME_LEN + 2)))
 816                         goto out;
 817                 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
 818         }
 819 out:
 820         i += sprintf(&buf[i], "\n");
 821         return i;
 822 }
 823 
 824 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
 825 {
 826         ssize_t i = 0;
 827         unsigned int cpu;
 828 
 829         for_each_cpu(cpu, mask) {
 830                 if (i)
 831                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 832                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 833                 if (i >= (PAGE_SIZE - 5))
 834                         break;
 835         }
 836         i += sprintf(&buf[i], "\n");
 837         return i;
 838 }
 839 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
 840 
 841 /**
 842  * show_related_cpus - show the CPUs affected by each transition even if
 843  * hw coordination is in use
 844  */
 845 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
 846 {
 847         return cpufreq_show_cpus(policy->related_cpus, buf);
 848 }
 849 
 850 /**
 851  * show_affected_cpus - show the CPUs affected by each transition
 852  */
 853 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
 854 {
 855         return cpufreq_show_cpus(policy->cpus, buf);
 856 }
 857 
 858 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
 859                                         const char *buf, size_t count)
 860 {
 861         unsigned int freq = 0;
 862         unsigned int ret;
 863 
 864         if (!policy->governor || !policy->governor->store_setspeed)
 865                 return -EINVAL;
 866 
 867         ret = sscanf(buf, "%u", &freq);
 868         if (ret != 1)
 869                 return -EINVAL;
 870 
 871         policy->governor->store_setspeed(policy, freq);
 872 
 873         return count;
 874 }
 875 
 876 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
 877 {
 878         if (!policy->governor || !policy->governor->show_setspeed)
 879                 return sprintf(buf, "<unsupported>\n");
 880 
 881         return policy->governor->show_setspeed(policy, buf);
 882 }
 883 
 884 /**
 885  * show_bios_limit - show the current cpufreq HW/BIOS limitation
 886  */
 887 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
 888 {
 889         unsigned int limit;
 890         int ret;
 891         ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
 892         if (!ret)
 893                 return sprintf(buf, "%u\n", limit);
 894         return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
 895 }
 896 
 897 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
 898 cpufreq_freq_attr_ro(cpuinfo_min_freq);
 899 cpufreq_freq_attr_ro(cpuinfo_max_freq);
 900 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
 901 cpufreq_freq_attr_ro(scaling_available_governors);
 902 cpufreq_freq_attr_ro(scaling_driver);
 903 cpufreq_freq_attr_ro(scaling_cur_freq);
 904 cpufreq_freq_attr_ro(bios_limit);
 905 cpufreq_freq_attr_ro(related_cpus);
 906 cpufreq_freq_attr_ro(affected_cpus);
 907 cpufreq_freq_attr_rw(scaling_min_freq);
 908 cpufreq_freq_attr_rw(scaling_max_freq);
 909 cpufreq_freq_attr_rw(scaling_governor);
 910 cpufreq_freq_attr_rw(scaling_setspeed);
 911 
 912 static struct attribute *default_attrs[] = {
 913         &cpuinfo_min_freq.attr,
 914         &cpuinfo_max_freq.attr,
 915         &cpuinfo_transition_latency.attr,
 916         &scaling_min_freq.attr,
 917         &scaling_max_freq.attr,
 918         &affected_cpus.attr,
 919         &related_cpus.attr,
 920         &scaling_governor.attr,
 921         &scaling_driver.attr,
 922         &scaling_available_governors.attr,
 923         &scaling_setspeed.attr,
 924         NULL
 925 };
 926 
 927 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 928 #define to_attr(a) container_of(a, struct freq_attr, attr)
 929 
 930 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
 931 {
 932         struct cpufreq_policy *policy = to_policy(kobj);
 933         struct freq_attr *fattr = to_attr(attr);
 934         ssize_t ret;
 935 
 936         if (!fattr->show)
 937                 return -EIO;
 938 
 939         down_read(&policy->rwsem);
 940         ret = fattr->show(policy, buf);
 941         up_read(&policy->rwsem);
 942 
 943         return ret;
 944 }
 945 
 946 static ssize_t store(struct kobject *kobj, struct attribute *attr,
 947                      const char *buf, size_t count)
 948 {
 949         struct cpufreq_policy *policy = to_policy(kobj);
 950         struct freq_attr *fattr = to_attr(attr);
 951         ssize_t ret = -EINVAL;
 952 
 953         if (!fattr->store)
 954                 return -EIO;
 955 
 956         /*
 957          * cpus_read_trylock() is used here to work around a circular lock
 958          * dependency problem with respect to the cpufreq_register_driver().
 959          */
 960         if (!cpus_read_trylock())
 961                 return -EBUSY;
 962 
 963         if (cpu_online(policy->cpu)) {
 964                 down_write(&policy->rwsem);
 965                 ret = fattr->store(policy, buf, count);
 966                 up_write(&policy->rwsem);
 967         }
 968 
 969         cpus_read_unlock();
 970 
 971         return ret;
 972 }
 973 
 974 static void cpufreq_sysfs_release(struct kobject *kobj)
 975 {
 976         struct cpufreq_policy *policy = to_policy(kobj);
 977         pr_debug("last reference is dropped\n");
 978         complete(&policy->kobj_unregister);
 979 }
 980 
 981 static const struct sysfs_ops sysfs_ops = {
 982         .show   = show,
 983         .store  = store,
 984 };
 985 
 986 static struct kobj_type ktype_cpufreq = {
 987         .sysfs_ops      = &sysfs_ops,
 988         .default_attrs  = default_attrs,
 989         .release        = cpufreq_sysfs_release,
 990 };
 991 
 992 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
 993 {
 994         struct device *dev = get_cpu_device(cpu);
 995 
 996         if (unlikely(!dev))
 997                 return;
 998 
 999         if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1000                 return;
1001 
1002         dev_dbg(dev, "%s: Adding symlink\n", __func__);
1003         if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1004                 dev_err(dev, "cpufreq symlink creation failed\n");
1005 }
1006 
1007 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
1008                                    struct device *dev)
1009 {
1010         dev_dbg(dev, "%s: Removing symlink\n", __func__);
1011         sysfs_remove_link(&dev->kobj, "cpufreq");
1012 }
1013 
1014 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1015 {
1016         struct freq_attr **drv_attr;
1017         int ret = 0;
1018 
1019         /* set up files for this cpu device */
1020         drv_attr = cpufreq_driver->attr;
1021         while (drv_attr && *drv_attr) {
1022                 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1023                 if (ret)
1024                         return ret;
1025                 drv_attr++;
1026         }
1027         if (cpufreq_driver->get) {
1028                 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1029                 if (ret)
1030                         return ret;
1031         }
1032 
1033         ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1034         if (ret)
1035                 return ret;
1036 
1037         if (cpufreq_driver->bios_limit) {
1038                 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1039                 if (ret)
1040                         return ret;
1041         }
1042 
1043         return 0;
1044 }
1045 
1046 __weak struct cpufreq_governor *cpufreq_default_governor(void)
1047 {
1048         return NULL;
1049 }
1050 
1051 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1052 {
1053         struct cpufreq_governor *def_gov = cpufreq_default_governor();
1054         struct cpufreq_governor *gov = NULL;
1055         unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
1056 
1057         if (has_target()) {
1058                 /* Update policy governor to the one used before hotplug. */
1059                 gov = find_governor(policy->last_governor);
1060                 if (gov) {
1061                         pr_debug("Restoring governor %s for cpu %d\n",
1062                                  policy->governor->name, policy->cpu);
1063                 } else if (def_gov) {
1064                         gov = def_gov;
1065                 } else {
1066                         return -ENODATA;
1067                 }
1068         } else {
1069                 /* Use the default policy if there is no last_policy. */
1070                 if (policy->last_policy) {
1071                         pol = policy->last_policy;
1072                 } else if (def_gov) {
1073                         pol = cpufreq_parse_policy(def_gov->name);
1074                         /*
1075                          * In case the default governor is neiter "performance"
1076                          * nor "powersave", fall back to the initial policy
1077                          * value set by the driver.
1078                          */
1079                         if (pol == CPUFREQ_POLICY_UNKNOWN)
1080                                 pol = policy->policy;
1081                 }
1082                 if (pol != CPUFREQ_POLICY_PERFORMANCE &&
1083                     pol != CPUFREQ_POLICY_POWERSAVE)
1084                         return -ENODATA;
1085         }
1086 
1087         return cpufreq_set_policy(policy, gov, pol);
1088 }
1089 
1090 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1091 {
1092         int ret = 0;
1093 
1094         /* Has this CPU been taken care of already? */
1095         if (cpumask_test_cpu(cpu, policy->cpus))
1096                 return 0;
1097 
1098         down_write(&policy->rwsem);
1099         if (has_target())
1100                 cpufreq_stop_governor(policy);
1101 
1102         cpumask_set_cpu(cpu, policy->cpus);
1103 
1104         if (has_target()) {
1105                 ret = cpufreq_start_governor(policy);
1106                 if (ret)
1107                         pr_err("%s: Failed to start governor\n", __func__);
1108         }
1109         up_write(&policy->rwsem);
1110         return ret;
1111 }
1112 
1113 void refresh_frequency_limits(struct cpufreq_policy *policy)
1114 {
1115         if (!policy_is_inactive(policy)) {
1116                 pr_debug("updating policy for CPU %u\n", policy->cpu);
1117 
1118                 cpufreq_set_policy(policy, policy->governor, policy->policy);
1119         }
1120 }
1121 EXPORT_SYMBOL(refresh_frequency_limits);
1122 
1123 static void handle_update(struct work_struct *work)
1124 {
1125         struct cpufreq_policy *policy =
1126                 container_of(work, struct cpufreq_policy, update);
1127 
1128         pr_debug("handle_update for cpu %u called\n", policy->cpu);
1129         down_write(&policy->rwsem);
1130         refresh_frequency_limits(policy);
1131         up_write(&policy->rwsem);
1132 }
1133 
1134 static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1135                                 void *data)
1136 {
1137         struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1138 
1139         schedule_work(&policy->update);
1140         return 0;
1141 }
1142 
1143 static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1144                                 void *data)
1145 {
1146         struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1147 
1148         schedule_work(&policy->update);
1149         return 0;
1150 }
1151 
1152 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1153 {
1154         struct kobject *kobj;
1155         struct completion *cmp;
1156 
1157         down_write(&policy->rwsem);
1158         cpufreq_stats_free_table(policy);
1159         kobj = &policy->kobj;
1160         cmp = &policy->kobj_unregister;
1161         up_write(&policy->rwsem);
1162         kobject_put(kobj);
1163 
1164         /*
1165          * We need to make sure that the underlying kobj is
1166          * actually not referenced anymore by anybody before we
1167          * proceed with unloading.
1168          */
1169         pr_debug("waiting for dropping of refcount\n");
1170         wait_for_completion(cmp);
1171         pr_debug("wait complete\n");
1172 }
1173 
1174 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1175 {
1176         struct cpufreq_policy *policy;
1177         struct device *dev = get_cpu_device(cpu);
1178         int ret;
1179 
1180         if (!dev)
1181                 return NULL;
1182 
1183         policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1184         if (!policy)
1185                 return NULL;
1186 
1187         if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1188                 goto err_free_policy;
1189 
1190         if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1191                 goto err_free_cpumask;
1192 
1193         if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1194                 goto err_free_rcpumask;
1195 
1196         ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1197                                    cpufreq_global_kobject, "policy%u", cpu);
1198         if (ret) {
1199                 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1200                 /*
1201                  * The entire policy object will be freed below, but the extra
1202                  * memory allocated for the kobject name needs to be freed by
1203                  * releasing the kobject.
1204                  */
1205                 kobject_put(&policy->kobj);
1206                 goto err_free_real_cpus;
1207         }
1208 
1209         freq_constraints_init(&policy->constraints);
1210 
1211         policy->nb_min.notifier_call = cpufreq_notifier_min;
1212         policy->nb_max.notifier_call = cpufreq_notifier_max;
1213 
1214         ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1215                                     &policy->nb_min);
1216         if (ret) {
1217                 dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
1218                         ret, cpumask_pr_args(policy->cpus));
1219                 goto err_kobj_remove;
1220         }
1221 
1222         ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1223                                     &policy->nb_max);
1224         if (ret) {
1225                 dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
1226                         ret, cpumask_pr_args(policy->cpus));
1227                 goto err_min_qos_notifier;
1228         }
1229 
1230         INIT_LIST_HEAD(&policy->policy_list);
1231         init_rwsem(&policy->rwsem);
1232         spin_lock_init(&policy->transition_lock);
1233         init_waitqueue_head(&policy->transition_wait);
1234         init_completion(&policy->kobj_unregister);
1235         INIT_WORK(&policy->update, handle_update);
1236 
1237         policy->cpu = cpu;
1238         return policy;
1239 
1240 err_min_qos_notifier:
1241         freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1242                                  &policy->nb_min);
1243 err_kobj_remove:
1244         cpufreq_policy_put_kobj(policy);
1245 err_free_real_cpus:
1246         free_cpumask_var(policy->real_cpus);
1247 err_free_rcpumask:
1248         free_cpumask_var(policy->related_cpus);
1249 err_free_cpumask:
1250         free_cpumask_var(policy->cpus);
1251 err_free_policy:
1252         kfree(policy);
1253 
1254         return NULL;
1255 }
1256 
1257 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1258 {
1259         unsigned long flags;
1260         int cpu;
1261 
1262         /* Remove policy from list */
1263         write_lock_irqsave(&cpufreq_driver_lock, flags);
1264         list_del(&policy->policy_list);
1265 
1266         for_each_cpu(cpu, policy->related_cpus)
1267                 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1268         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1269 
1270         freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1271                                  &policy->nb_max);
1272         freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1273                                  &policy->nb_min);
1274 
1275         /* Cancel any pending policy->update work before freeing the policy. */
1276         cancel_work_sync(&policy->update);
1277 
1278         if (policy->max_freq_req) {
1279                 /*
1280                  * CPUFREQ_CREATE_POLICY notification is sent only after
1281                  * successfully adding max_freq_req request.
1282                  */
1283                 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1284                                              CPUFREQ_REMOVE_POLICY, policy);
1285                 freq_qos_remove_request(policy->max_freq_req);
1286         }
1287 
1288         freq_qos_remove_request(policy->min_freq_req);
1289         kfree(policy->min_freq_req);
1290 
1291         cpufreq_policy_put_kobj(policy);
1292         free_cpumask_var(policy->real_cpus);
1293         free_cpumask_var(policy->related_cpus);
1294         free_cpumask_var(policy->cpus);
1295         kfree(policy);
1296 }
1297 
1298 static int cpufreq_online(unsigned int cpu)
1299 {
1300         struct cpufreq_policy *policy;
1301         bool new_policy;
1302         unsigned long flags;
1303         unsigned int j;
1304         int ret;
1305 
1306         pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1307 
1308         /* Check if this CPU already has a policy to manage it */
1309         policy = per_cpu(cpufreq_cpu_data, cpu);
1310         if (policy) {
1311                 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1312                 if (!policy_is_inactive(policy))
1313                         return cpufreq_add_policy_cpu(policy, cpu);
1314 
1315                 /* This is the only online CPU for the policy.  Start over. */
1316                 new_policy = false;
1317                 down_write(&policy->rwsem);
1318                 policy->cpu = cpu;
1319                 policy->governor = NULL;
1320                 up_write(&policy->rwsem);
1321         } else {
1322                 new_policy = true;
1323                 policy = cpufreq_policy_alloc(cpu);
1324                 if (!policy)
1325                         return -ENOMEM;
1326         }
1327 
1328         if (!new_policy && cpufreq_driver->online) {
1329                 ret = cpufreq_driver->online(policy);
1330                 if (ret) {
1331                         pr_debug("%s: %d: initialization failed\n", __func__,
1332                                  __LINE__);
1333                         goto out_exit_policy;
1334                 }
1335 
1336                 /* Recover policy->cpus using related_cpus */
1337                 cpumask_copy(policy->cpus, policy->related_cpus);
1338         } else {
1339                 cpumask_copy(policy->cpus, cpumask_of(cpu));
1340 
1341                 /*
1342                  * Call driver. From then on the cpufreq must be able
1343                  * to accept all calls to ->verify and ->setpolicy for this CPU.
1344                  */
1345                 ret = cpufreq_driver->init(policy);
1346                 if (ret) {
1347                         pr_debug("%s: %d: initialization failed\n", __func__,
1348                                  __LINE__);
1349                         goto out_free_policy;
1350                 }
1351 
1352                 ret = cpufreq_table_validate_and_sort(policy);
1353                 if (ret)
1354                         goto out_exit_policy;
1355 
1356                 /* related_cpus should at least include policy->cpus. */
1357                 cpumask_copy(policy->related_cpus, policy->cpus);
1358         }
1359 
1360         down_write(&policy->rwsem);
1361         /*
1362          * affected cpus must always be the one, which are online. We aren't
1363          * managing offline cpus here.
1364          */
1365         cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1366 
1367         if (new_policy) {
1368                 for_each_cpu(j, policy->related_cpus) {
1369                         per_cpu(cpufreq_cpu_data, j) = policy;
1370                         add_cpu_dev_symlink(policy, j);
1371                 }
1372 
1373                 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1374                                                GFP_KERNEL);
1375                 if (!policy->min_freq_req)
1376                         goto out_destroy_policy;
1377 
1378                 ret = freq_qos_add_request(&policy->constraints,
1379                                            policy->min_freq_req, FREQ_QOS_MIN,
1380                                            policy->min);
1381                 if (ret < 0) {
1382                         /*
1383                          * So we don't call freq_qos_remove_request() for an
1384                          * uninitialized request.
1385                          */
1386                         kfree(policy->min_freq_req);
1387                         policy->min_freq_req = NULL;
1388                         goto out_destroy_policy;
1389                 }
1390 
1391                 /*
1392                  * This must be initialized right here to avoid calling
1393                  * freq_qos_remove_request() on uninitialized request in case
1394                  * of errors.
1395                  */
1396                 policy->max_freq_req = policy->min_freq_req + 1;
1397 
1398                 ret = freq_qos_add_request(&policy->constraints,
1399                                            policy->max_freq_req, FREQ_QOS_MAX,
1400                                            policy->max);
1401                 if (ret < 0) {
1402                         policy->max_freq_req = NULL;
1403                         goto out_destroy_policy;
1404                 }
1405 
1406                 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1407                                 CPUFREQ_CREATE_POLICY, policy);
1408         }
1409 
1410         if (cpufreq_driver->get && has_target()) {
1411                 policy->cur = cpufreq_driver->get(policy->cpu);
1412                 if (!policy->cur) {
1413                         pr_err("%s: ->get() failed\n", __func__);
1414                         goto out_destroy_policy;
1415                 }
1416         }
1417 
1418         /*
1419          * Sometimes boot loaders set CPU frequency to a value outside of
1420          * frequency table present with cpufreq core. In such cases CPU might be
1421          * unstable if it has to run on that frequency for long duration of time
1422          * and so its better to set it to a frequency which is specified in
1423          * freq-table. This also makes cpufreq stats inconsistent as
1424          * cpufreq-stats would fail to register because current frequency of CPU
1425          * isn't found in freq-table.
1426          *
1427          * Because we don't want this change to effect boot process badly, we go
1428          * for the next freq which is >= policy->cur ('cur' must be set by now,
1429          * otherwise we will end up setting freq to lowest of the table as 'cur'
1430          * is initialized to zero).
1431          *
1432          * We are passing target-freq as "policy->cur - 1" otherwise
1433          * __cpufreq_driver_target() would simply fail, as policy->cur will be
1434          * equal to target-freq.
1435          */
1436         if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1437             && has_target()) {
1438                 /* Are we running at unknown frequency ? */
1439                 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1440                 if (ret == -EINVAL) {
1441                         /* Warn user and fix it */
1442                         pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1443                                 __func__, policy->cpu, policy->cur);
1444                         ret = __cpufreq_driver_target(policy, policy->cur - 1,
1445                                 CPUFREQ_RELATION_L);
1446 
1447                         /*
1448                          * Reaching here after boot in a few seconds may not
1449                          * mean that system will remain stable at "unknown"
1450                          * frequency for longer duration. Hence, a BUG_ON().
1451                          */
1452                         BUG_ON(ret);
1453                         pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1454                                 __func__, policy->cpu, policy->cur);
1455                 }
1456         }
1457 
1458         if (new_policy) {
1459                 ret = cpufreq_add_dev_interface(policy);
1460                 if (ret)
1461                         goto out_destroy_policy;
1462 
1463                 cpufreq_stats_create_table(policy);
1464 
1465                 write_lock_irqsave(&cpufreq_driver_lock, flags);
1466                 list_add(&policy->policy_list, &cpufreq_policy_list);
1467                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1468         }
1469 
1470         ret = cpufreq_init_policy(policy);
1471         if (ret) {
1472                 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1473                        __func__, cpu, ret);
1474                 goto out_destroy_policy;
1475         }
1476 
1477         up_write(&policy->rwsem);
1478 
1479         kobject_uevent(&policy->kobj, KOBJ_ADD);
1480 
1481         /* Callback for handling stuff after policy is ready */
1482         if (cpufreq_driver->ready)
1483                 cpufreq_driver->ready(policy);
1484 
1485         if (cpufreq_thermal_control_enabled(cpufreq_driver))
1486                 policy->cdev = of_cpufreq_cooling_register(policy);
1487 
1488         pr_debug("initialization complete\n");
1489 
1490         return 0;
1491 
1492 out_destroy_policy:
1493         for_each_cpu(j, policy->real_cpus)
1494                 remove_cpu_dev_symlink(policy, get_cpu_device(j));
1495 
1496         up_write(&policy->rwsem);
1497 
1498 out_exit_policy:
1499         if (cpufreq_driver->exit)
1500                 cpufreq_driver->exit(policy);
1501 
1502 out_free_policy:
1503         cpufreq_policy_free(policy);
1504         return ret;
1505 }
1506 
1507 /**
1508  * cpufreq_add_dev - the cpufreq interface for a CPU device.
1509  * @dev: CPU device.
1510  * @sif: Subsystem interface structure pointer (not used)
1511  */
1512 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1513 {
1514         struct cpufreq_policy *policy;
1515         unsigned cpu = dev->id;
1516         int ret;
1517 
1518         dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1519 
1520         if (cpu_online(cpu)) {
1521                 ret = cpufreq_online(cpu);
1522                 if (ret)
1523                         return ret;
1524         }
1525 
1526         /* Create sysfs link on CPU registration */
1527         policy = per_cpu(cpufreq_cpu_data, cpu);
1528         if (policy)
1529                 add_cpu_dev_symlink(policy, cpu);
1530 
1531         return 0;
1532 }
1533 
1534 static int cpufreq_offline(unsigned int cpu)
1535 {
1536         struct cpufreq_policy *policy;
1537         int ret;
1538 
1539         pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1540 
1541         policy = cpufreq_cpu_get_raw(cpu);
1542         if (!policy) {
1543                 pr_debug("%s: No cpu_data found\n", __func__);
1544                 return 0;
1545         }
1546 
1547         down_write(&policy->rwsem);
1548         if (has_target())
1549                 cpufreq_stop_governor(policy);
1550 
1551         cpumask_clear_cpu(cpu, policy->cpus);
1552 
1553         if (policy_is_inactive(policy)) {
1554                 if (has_target())
1555                         strncpy(policy->last_governor, policy->governor->name,
1556                                 CPUFREQ_NAME_LEN);
1557                 else
1558                         policy->last_policy = policy->policy;
1559         } else if (cpu == policy->cpu) {
1560                 /* Nominate new CPU */
1561                 policy->cpu = cpumask_any(policy->cpus);
1562         }
1563 
1564         /* Start governor again for active policy */
1565         if (!policy_is_inactive(policy)) {
1566                 if (has_target()) {
1567                         ret = cpufreq_start_governor(policy);
1568                         if (ret)
1569                                 pr_err("%s: Failed to start governor\n", __func__);
1570                 }
1571 
1572                 goto unlock;
1573         }
1574 
1575         if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1576                 cpufreq_cooling_unregister(policy->cdev);
1577                 policy->cdev = NULL;
1578         }
1579 
1580         if (cpufreq_driver->stop_cpu)
1581                 cpufreq_driver->stop_cpu(policy);
1582 
1583         if (has_target())
1584                 cpufreq_exit_governor(policy);
1585 
1586         /*
1587          * Perform the ->offline() during light-weight tear-down, as
1588          * that allows fast recovery when the CPU comes back.
1589          */
1590         if (cpufreq_driver->offline) {
1591                 cpufreq_driver->offline(policy);
1592         } else if (cpufreq_driver->exit) {
1593                 cpufreq_driver->exit(policy);
1594                 policy->freq_table = NULL;
1595         }
1596 
1597 unlock:
1598         up_write(&policy->rwsem);
1599         return 0;
1600 }
1601 
1602 /**
1603  * cpufreq_remove_dev - remove a CPU device
1604  *
1605  * Removes the cpufreq interface for a CPU device.
1606  */
1607 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1608 {
1609         unsigned int cpu = dev->id;
1610         struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1611 
1612         if (!policy)
1613                 return;
1614 
1615         if (cpu_online(cpu))
1616                 cpufreq_offline(cpu);
1617 
1618         cpumask_clear_cpu(cpu, policy->real_cpus);
1619         remove_cpu_dev_symlink(policy, dev);
1620 
1621         if (cpumask_empty(policy->real_cpus)) {
1622                 /* We did light-weight exit earlier, do full tear down now */
1623                 if (cpufreq_driver->offline)
1624                         cpufreq_driver->exit(policy);
1625 
1626                 cpufreq_policy_free(policy);
1627         }
1628 }
1629 
1630 /**
1631  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1632  *      in deep trouble.
1633  *      @policy: policy managing CPUs
1634  *      @new_freq: CPU frequency the CPU actually runs at
1635  *
1636  *      We adjust to current frequency first, and need to clean up later.
1637  *      So either call to cpufreq_update_policy() or schedule handle_update()).
1638  */
1639 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1640                                 unsigned int new_freq)
1641 {
1642         struct cpufreq_freqs freqs;
1643 
1644         pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1645                  policy->cur, new_freq);
1646 
1647         freqs.old = policy->cur;
1648         freqs.new = new_freq;
1649 
1650         cpufreq_freq_transition_begin(policy, &freqs);
1651         cpufreq_freq_transition_end(policy, &freqs, 0);
1652 }
1653 
1654 static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1655 {
1656         unsigned int new_freq;
1657 
1658         new_freq = cpufreq_driver->get(policy->cpu);
1659         if (!new_freq)
1660                 return 0;
1661 
1662         /*
1663          * If fast frequency switching is used with the given policy, the check
1664          * against policy->cur is pointless, so skip it in that case.
1665          */
1666         if (policy->fast_switch_enabled || !has_target())
1667                 return new_freq;
1668 
1669         if (policy->cur != new_freq) {
1670                 cpufreq_out_of_sync(policy, new_freq);
1671                 if (update)
1672                         schedule_work(&policy->update);
1673         }
1674 
1675         return new_freq;
1676 }
1677 
1678 /**
1679  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1680  * @cpu: CPU number
1681  *
1682  * This is the last known freq, without actually getting it from the driver.
1683  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1684  */
1685 unsigned int cpufreq_quick_get(unsigned int cpu)
1686 {
1687         struct cpufreq_policy *policy;
1688         unsigned int ret_freq = 0;
1689         unsigned long flags;
1690 
1691         read_lock_irqsave(&cpufreq_driver_lock, flags);
1692 
1693         if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1694                 ret_freq = cpufreq_driver->get(cpu);
1695                 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1696                 return ret_freq;
1697         }
1698 
1699         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1700 
1701         policy = cpufreq_cpu_get(cpu);
1702         if (policy) {
1703                 ret_freq = policy->cur;
1704                 cpufreq_cpu_put(policy);
1705         }
1706 
1707         return ret_freq;
1708 }
1709 EXPORT_SYMBOL(cpufreq_quick_get);
1710 
1711 /**
1712  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1713  * @cpu: CPU number
1714  *
1715  * Just return the max possible frequency for a given CPU.
1716  */
1717 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1718 {
1719         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1720         unsigned int ret_freq = 0;
1721 
1722         if (policy) {
1723                 ret_freq = policy->max;
1724                 cpufreq_cpu_put(policy);
1725         }
1726 
1727         return ret_freq;
1728 }
1729 EXPORT_SYMBOL(cpufreq_quick_get_max);
1730 
1731 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1732 {
1733         if (unlikely(policy_is_inactive(policy)))
1734                 return 0;
1735 
1736         return cpufreq_verify_current_freq(policy, true);
1737 }
1738 
1739 /**
1740  * cpufreq_get - get the current CPU frequency (in kHz)
1741  * @cpu: CPU number
1742  *
1743  * Get the CPU current (static) CPU frequency
1744  */
1745 unsigned int cpufreq_get(unsigned int cpu)
1746 {
1747         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1748         unsigned int ret_freq = 0;
1749 
1750         if (policy) {
1751                 down_read(&policy->rwsem);
1752                 if (cpufreq_driver->get)
1753                         ret_freq = __cpufreq_get(policy);
1754                 up_read(&policy->rwsem);
1755 
1756                 cpufreq_cpu_put(policy);
1757         }
1758 
1759         return ret_freq;
1760 }
1761 EXPORT_SYMBOL(cpufreq_get);
1762 
1763 static struct subsys_interface cpufreq_interface = {
1764         .name           = "cpufreq",
1765         .subsys         = &cpu_subsys,
1766         .add_dev        = cpufreq_add_dev,
1767         .remove_dev     = cpufreq_remove_dev,
1768 };
1769 
1770 /*
1771  * In case platform wants some specific frequency to be configured
1772  * during suspend..
1773  */
1774 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1775 {
1776         int ret;
1777 
1778         if (!policy->suspend_freq) {
1779                 pr_debug("%s: suspend_freq not defined\n", __func__);
1780                 return 0;
1781         }
1782 
1783         pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1784                         policy->suspend_freq);
1785 
1786         ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1787                         CPUFREQ_RELATION_H);
1788         if (ret)
1789                 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1790                                 __func__, policy->suspend_freq, ret);
1791 
1792         return ret;
1793 }
1794 EXPORT_SYMBOL(cpufreq_generic_suspend);
1795 
1796 /**
1797  * cpufreq_suspend() - Suspend CPUFreq governors
1798  *
1799  * Called during system wide Suspend/Hibernate cycles for suspending governors
1800  * as some platforms can't change frequency after this point in suspend cycle.
1801  * Because some of the devices (like: i2c, regulators, etc) they use for
1802  * changing frequency are suspended quickly after this point.
1803  */
1804 void cpufreq_suspend(void)
1805 {
1806         struct cpufreq_policy *policy;
1807 
1808         if (!cpufreq_driver)
1809                 return;
1810 
1811         if (!has_target() && !cpufreq_driver->suspend)
1812                 goto suspend;
1813 
1814         pr_debug("%s: Suspending Governors\n", __func__);
1815 
1816         for_each_active_policy(policy) {
1817                 if (has_target()) {
1818                         down_write(&policy->rwsem);
1819                         cpufreq_stop_governor(policy);
1820                         up_write(&policy->rwsem);
1821                 }
1822 
1823                 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1824                         pr_err("%s: Failed to suspend driver: %s\n", __func__,
1825                                 cpufreq_driver->name);
1826         }
1827 
1828 suspend:
1829         cpufreq_suspended = true;
1830 }
1831 
1832 /**
1833  * cpufreq_resume() - Resume CPUFreq governors
1834  *
1835  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1836  * are suspended with cpufreq_suspend().
1837  */
1838 void cpufreq_resume(void)
1839 {
1840         struct cpufreq_policy *policy;
1841         int ret;
1842 
1843         if (!cpufreq_driver)
1844                 return;
1845 
1846         if (unlikely(!cpufreq_suspended))
1847                 return;
1848 
1849         cpufreq_suspended = false;
1850 
1851         if (!has_target() && !cpufreq_driver->resume)
1852                 return;
1853 
1854         pr_debug("%s: Resuming Governors\n", __func__);
1855 
1856         for_each_active_policy(policy) {
1857                 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1858                         pr_err("%s: Failed to resume driver: %p\n", __func__,
1859                                 policy);
1860                 } else if (has_target()) {
1861                         down_write(&policy->rwsem);
1862                         ret = cpufreq_start_governor(policy);
1863                         up_write(&policy->rwsem);
1864 
1865                         if (ret)
1866                                 pr_err("%s: Failed to start governor for policy: %p\n",
1867                                        __func__, policy);
1868                 }
1869         }
1870 }
1871 
1872 /**
1873  *      cpufreq_get_current_driver - return current driver's name
1874  *
1875  *      Return the name string of the currently loaded cpufreq driver
1876  *      or NULL, if none.
1877  */
1878 const char *cpufreq_get_current_driver(void)
1879 {
1880         if (cpufreq_driver)
1881                 return cpufreq_driver->name;
1882 
1883         return NULL;
1884 }
1885 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1886 
1887 /**
1888  *      cpufreq_get_driver_data - return current driver data
1889  *
1890  *      Return the private data of the currently loaded cpufreq
1891  *      driver, or NULL if no cpufreq driver is loaded.
1892  */
1893 void *cpufreq_get_driver_data(void)
1894 {
1895         if (cpufreq_driver)
1896                 return cpufreq_driver->driver_data;
1897 
1898         return NULL;
1899 }
1900 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1901 
1902 /*********************************************************************
1903  *                     NOTIFIER LISTS INTERFACE                      *
1904  *********************************************************************/
1905 
1906 /**
1907  *      cpufreq_register_notifier - register a driver with cpufreq
1908  *      @nb: notifier function to register
1909  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1910  *
1911  *      Add a driver to one of two lists: either a list of drivers that
1912  *      are notified about clock rate changes (once before and once after
1913  *      the transition), or a list of drivers that are notified about
1914  *      changes in cpufreq policy.
1915  *
1916  *      This function may sleep, and has the same return conditions as
1917  *      blocking_notifier_chain_register.
1918  */
1919 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1920 {
1921         int ret;
1922 
1923         if (cpufreq_disabled())
1924                 return -EINVAL;
1925 
1926         switch (list) {
1927         case CPUFREQ_TRANSITION_NOTIFIER:
1928                 mutex_lock(&cpufreq_fast_switch_lock);
1929 
1930                 if (cpufreq_fast_switch_count > 0) {
1931                         mutex_unlock(&cpufreq_fast_switch_lock);
1932                         return -EBUSY;
1933                 }
1934                 ret = srcu_notifier_chain_register(
1935                                 &cpufreq_transition_notifier_list, nb);
1936                 if (!ret)
1937                         cpufreq_fast_switch_count--;
1938 
1939                 mutex_unlock(&cpufreq_fast_switch_lock);
1940                 break;
1941         case CPUFREQ_POLICY_NOTIFIER:
1942                 ret = blocking_notifier_chain_register(
1943                                 &cpufreq_policy_notifier_list, nb);
1944                 break;
1945         default:
1946                 ret = -EINVAL;
1947         }
1948 
1949         return ret;
1950 }
1951 EXPORT_SYMBOL(cpufreq_register_notifier);
1952 
1953 /**
1954  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1955  *      @nb: notifier block to be unregistered
1956  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1957  *
1958  *      Remove a driver from the CPU frequency notifier list.
1959  *
1960  *      This function may sleep, and has the same return conditions as
1961  *      blocking_notifier_chain_unregister.
1962  */
1963 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1964 {
1965         int ret;
1966 
1967         if (cpufreq_disabled())
1968                 return -EINVAL;
1969 
1970         switch (list) {
1971         case CPUFREQ_TRANSITION_NOTIFIER:
1972                 mutex_lock(&cpufreq_fast_switch_lock);
1973 
1974                 ret = srcu_notifier_chain_unregister(
1975                                 &cpufreq_transition_notifier_list, nb);
1976                 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1977                         cpufreq_fast_switch_count++;
1978 
1979                 mutex_unlock(&cpufreq_fast_switch_lock);
1980                 break;
1981         case CPUFREQ_POLICY_NOTIFIER:
1982                 ret = blocking_notifier_chain_unregister(
1983                                 &cpufreq_policy_notifier_list, nb);
1984                 break;
1985         default:
1986                 ret = -EINVAL;
1987         }
1988 
1989         return ret;
1990 }
1991 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1992 
1993 
1994 /*********************************************************************
1995  *                              GOVERNORS                            *
1996  *********************************************************************/
1997 
1998 /**
1999  * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
2000  * @policy: cpufreq policy to switch the frequency for.
2001  * @target_freq: New frequency to set (may be approximate).
2002  *
2003  * Carry out a fast frequency switch without sleeping.
2004  *
2005  * The driver's ->fast_switch() callback invoked by this function must be
2006  * suitable for being called from within RCU-sched read-side critical sections
2007  * and it is expected to select the minimum available frequency greater than or
2008  * equal to @target_freq (CPUFREQ_RELATION_L).
2009  *
2010  * This function must not be called if policy->fast_switch_enabled is unset.
2011  *
2012  * Governors calling this function must guarantee that it will never be invoked
2013  * twice in parallel for the same policy and that it will never be called in
2014  * parallel with either ->target() or ->target_index() for the same policy.
2015  *
2016  * Returns the actual frequency set for the CPU.
2017  *
2018  * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2019  * error condition, the hardware configuration must be preserved.
2020  */
2021 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2022                                         unsigned int target_freq)
2023 {
2024         target_freq = clamp_val(target_freq, policy->min, policy->max);
2025 
2026         return cpufreq_driver->fast_switch(policy, target_freq);
2027 }
2028 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2029 
2030 /* Must set freqs->new to intermediate frequency */
2031 static int __target_intermediate(struct cpufreq_policy *policy,
2032                                  struct cpufreq_freqs *freqs, int index)
2033 {
2034         int ret;
2035 
2036         freqs->new = cpufreq_driver->get_intermediate(policy, index);
2037 
2038         /* We don't need to switch to intermediate freq */
2039         if (!freqs->new)
2040                 return 0;
2041 
2042         pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2043                  __func__, policy->cpu, freqs->old, freqs->new);
2044 
2045         cpufreq_freq_transition_begin(policy, freqs);
2046         ret = cpufreq_driver->target_intermediate(policy, index);
2047         cpufreq_freq_transition_end(policy, freqs, ret);
2048 
2049         if (ret)
2050                 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2051                        __func__, ret);
2052 
2053         return ret;
2054 }
2055 
2056 static int __target_index(struct cpufreq_policy *policy, int index)
2057 {
2058         struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2059         unsigned int intermediate_freq = 0;
2060         unsigned int newfreq = policy->freq_table[index].frequency;
2061         int retval = -EINVAL;
2062         bool notify;
2063 
2064         if (newfreq == policy->cur)
2065                 return 0;
2066 
2067         notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2068         if (notify) {
2069                 /* Handle switching to intermediate frequency */
2070                 if (cpufreq_driver->get_intermediate) {
2071                         retval = __target_intermediate(policy, &freqs, index);
2072                         if (retval)
2073                                 return retval;
2074 
2075                         intermediate_freq = freqs.new;
2076                         /* Set old freq to intermediate */
2077                         if (intermediate_freq)
2078                                 freqs.old = freqs.new;
2079                 }
2080 
2081                 freqs.new = newfreq;
2082                 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2083                          __func__, policy->cpu, freqs.old, freqs.new);
2084 
2085                 cpufreq_freq_transition_begin(policy, &freqs);
2086         }
2087 
2088         retval = cpufreq_driver->target_index(policy, index);
2089         if (retval)
2090                 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2091                        retval);
2092 
2093         if (notify) {
2094                 cpufreq_freq_transition_end(policy, &freqs, retval);
2095 
2096                 /*
2097                  * Failed after setting to intermediate freq? Driver should have
2098                  * reverted back to initial frequency and so should we. Check
2099                  * here for intermediate_freq instead of get_intermediate, in
2100                  * case we haven't switched to intermediate freq at all.
2101                  */
2102                 if (unlikely(retval && intermediate_freq)) {
2103                         freqs.old = intermediate_freq;
2104                         freqs.new = policy->restore_freq;
2105                         cpufreq_freq_transition_begin(policy, &freqs);
2106                         cpufreq_freq_transition_end(policy, &freqs, 0);
2107                 }
2108         }
2109 
2110         return retval;
2111 }
2112 
2113 int __cpufreq_driver_target(struct cpufreq_policy *policy,
2114                             unsigned int target_freq,
2115                             unsigned int relation)
2116 {
2117         unsigned int old_target_freq = target_freq;
2118         int index;
2119 
2120         if (cpufreq_disabled())
2121                 return -ENODEV;
2122 
2123         /* Make sure that target_freq is within supported range */
2124         target_freq = clamp_val(target_freq, policy->min, policy->max);
2125 
2126         pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2127                  policy->cpu, target_freq, relation, old_target_freq);
2128 
2129         /*
2130          * This might look like a redundant call as we are checking it again
2131          * after finding index. But it is left intentionally for cases where
2132          * exactly same freq is called again and so we can save on few function
2133          * calls.
2134          */
2135         if (target_freq == policy->cur)
2136                 return 0;
2137 
2138         /* Save last value to restore later on errors */
2139         policy->restore_freq = policy->cur;
2140 
2141         if (cpufreq_driver->target)
2142                 return cpufreq_driver->target(policy, target_freq, relation);
2143 
2144         if (!cpufreq_driver->target_index)
2145                 return -EINVAL;
2146 
2147         index = cpufreq_frequency_table_target(policy, target_freq, relation);
2148 
2149         return __target_index(policy, index);
2150 }
2151 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2152 
2153 int cpufreq_driver_target(struct cpufreq_policy *policy,
2154                           unsigned int target_freq,
2155                           unsigned int relation)
2156 {
2157         int ret;
2158 
2159         down_write(&policy->rwsem);
2160 
2161         ret = __cpufreq_driver_target(policy, target_freq, relation);
2162 
2163         up_write(&policy->rwsem);
2164 
2165         return ret;
2166 }
2167 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2168 
2169 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2170 {
2171         return NULL;
2172 }
2173 
2174 static int cpufreq_init_governor(struct cpufreq_policy *policy)
2175 {
2176         int ret;
2177 
2178         /* Don't start any governor operations if we are entering suspend */
2179         if (cpufreq_suspended)
2180                 return 0;
2181         /*
2182          * Governor might not be initiated here if ACPI _PPC changed
2183          * notification happened, so check it.
2184          */
2185         if (!policy->governor)
2186                 return -EINVAL;
2187 
2188         /* Platform doesn't want dynamic frequency switching ? */
2189         if (policy->governor->dynamic_switching &&
2190             cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2191                 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2192 
2193                 if (gov) {
2194                         pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2195                                 policy->governor->name, gov->name);
2196                         policy->governor = gov;
2197                 } else {
2198                         return -EINVAL;
2199                 }
2200         }
2201 
2202         if (!try_module_get(policy->governor->owner))
2203                 return -EINVAL;
2204 
2205         pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2206 
2207         if (policy->governor->init) {
2208                 ret = policy->governor->init(policy);
2209                 if (ret) {
2210                         module_put(policy->governor->owner);
2211                         return ret;
2212                 }
2213         }
2214 
2215         return 0;
2216 }
2217 
2218 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2219 {
2220         if (cpufreq_suspended || !policy->governor)
2221                 return;
2222 
2223         pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2224 
2225         if (policy->governor->exit)
2226                 policy->governor->exit(policy);
2227 
2228         module_put(policy->governor->owner);
2229 }
2230 
2231 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2232 {
2233         int ret;
2234 
2235         if (cpufreq_suspended)
2236                 return 0;
2237 
2238         if (!policy->governor)
2239                 return -EINVAL;
2240 
2241         pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2242 
2243         if (cpufreq_driver->get)
2244                 cpufreq_verify_current_freq(policy, false);
2245 
2246         if (policy->governor->start) {
2247                 ret = policy->governor->start(policy);
2248                 if (ret)
2249                         return ret;
2250         }
2251 
2252         if (policy->governor->limits)
2253                 policy->governor->limits(policy);
2254 
2255         return 0;
2256 }
2257 
2258 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2259 {
2260         if (cpufreq_suspended || !policy->governor)
2261                 return;
2262 
2263         pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2264 
2265         if (policy->governor->stop)
2266                 policy->governor->stop(policy);
2267 }
2268 
2269 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2270 {
2271         if (cpufreq_suspended || !policy->governor)
2272                 return;
2273 
2274         pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2275 
2276         if (policy->governor->limits)
2277                 policy->governor->limits(policy);
2278 }
2279 
2280 int cpufreq_register_governor(struct cpufreq_governor *governor)
2281 {
2282         int err;
2283 
2284         if (!governor)
2285                 return -EINVAL;
2286 
2287         if (cpufreq_disabled())
2288                 return -ENODEV;
2289 
2290         mutex_lock(&cpufreq_governor_mutex);
2291 
2292         err = -EBUSY;
2293         if (!find_governor(governor->name)) {
2294                 err = 0;
2295                 list_add(&governor->governor_list, &cpufreq_governor_list);
2296         }
2297 
2298         mutex_unlock(&cpufreq_governor_mutex);
2299         return err;
2300 }
2301 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2302 
2303 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2304 {
2305         struct cpufreq_policy *policy;
2306         unsigned long flags;
2307 
2308         if (!governor)
2309                 return;
2310 
2311         if (cpufreq_disabled())
2312                 return;
2313 
2314         /* clear last_governor for all inactive policies */
2315         read_lock_irqsave(&cpufreq_driver_lock, flags);
2316         for_each_inactive_policy(policy) {
2317                 if (!strcmp(policy->last_governor, governor->name)) {
2318                         policy->governor = NULL;
2319                         strcpy(policy->last_governor, "\0");
2320                 }
2321         }
2322         read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2323 
2324         mutex_lock(&cpufreq_governor_mutex);
2325         list_del(&governor->governor_list);
2326         mutex_unlock(&cpufreq_governor_mutex);
2327 }
2328 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2329 
2330 
2331 /*********************************************************************
2332  *                          POLICY INTERFACE                         *
2333  *********************************************************************/
2334 
2335 /**
2336  * cpufreq_get_policy - get the current cpufreq_policy
2337  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2338  *      is written
2339  *
2340  * Reads the current cpufreq policy.
2341  */
2342 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2343 {
2344         struct cpufreq_policy *cpu_policy;
2345         if (!policy)
2346                 return -EINVAL;
2347 
2348         cpu_policy = cpufreq_cpu_get(cpu);
2349         if (!cpu_policy)
2350                 return -EINVAL;
2351 
2352         memcpy(policy, cpu_policy, sizeof(*policy));
2353 
2354         cpufreq_cpu_put(cpu_policy);
2355         return 0;
2356 }
2357 EXPORT_SYMBOL(cpufreq_get_policy);
2358 
2359 /**
2360  * cpufreq_set_policy - Modify cpufreq policy parameters.
2361  * @policy: Policy object to modify.
2362  * @new_gov: Policy governor pointer.
2363  * @new_pol: Policy value (for drivers with built-in governors).
2364  *
2365  * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
2366  * limits to be set for the policy, update @policy with the verified limits
2367  * values and either invoke the driver's ->setpolicy() callback (if present) or
2368  * carry out a governor update for @policy.  That is, run the current governor's
2369  * ->limits() callback (if @new_gov points to the same object as the one in
2370  * @policy) or replace the governor for @policy with @new_gov.
2371  *
2372  * The cpuinfo part of @policy is not updated by this function.
2373  */
2374 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2375                               struct cpufreq_governor *new_gov,
2376                               unsigned int new_pol)
2377 {
2378         struct cpufreq_policy_data new_data;
2379         struct cpufreq_governor *old_gov;
2380         int ret;
2381 
2382         memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2383         new_data.freq_table = policy->freq_table;
2384         new_data.cpu = policy->cpu;
2385         /*
2386          * PM QoS framework collects all the requests from users and provide us
2387          * the final aggregated value here.
2388          */
2389         new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2390         new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2391 
2392         pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2393                  new_data.cpu, new_data.min, new_data.max);
2394 
2395         /* verify the cpu speed can be set within this limit */
2396         ret = cpufreq_driver->verify(&new_data);
2397         if (ret)
2398                 return ret;
2399 
2400         policy->min = new_data.min;
2401         policy->max = new_data.max;
2402         trace_cpu_frequency_limits(policy);
2403 
2404         policy->cached_target_freq = UINT_MAX;
2405 
2406         pr_debug("new min and max freqs are %u - %u kHz\n",
2407                  policy->min, policy->max);
2408 
2409         if (cpufreq_driver->setpolicy) {
2410                 policy->policy = new_pol;
2411                 pr_debug("setting range\n");
2412                 return cpufreq_driver->setpolicy(policy);
2413         }
2414 
2415         if (new_gov == policy->governor) {
2416                 pr_debug("governor limits update\n");
2417                 cpufreq_governor_limits(policy);
2418                 return 0;
2419         }
2420 
2421         pr_debug("governor switch\n");
2422 
2423         /* save old, working values */
2424         old_gov = policy->governor;
2425         /* end old governor */
2426         if (old_gov) {
2427                 cpufreq_stop_governor(policy);
2428                 cpufreq_exit_governor(policy);
2429         }
2430 
2431         /* start new governor */
2432         policy->governor = new_gov;
2433         ret = cpufreq_init_governor(policy);
2434         if (!ret) {
2435                 ret = cpufreq_start_governor(policy);
2436                 if (!ret) {
2437                         pr_debug("governor change\n");
2438                         sched_cpufreq_governor_change(policy, old_gov);
2439                         return 0;
2440                 }
2441                 cpufreq_exit_governor(policy);
2442         }
2443 
2444         /* new governor failed, so re-start old one */
2445         pr_debug("starting governor %s failed\n", policy->governor->name);
2446         if (old_gov) {
2447                 policy->governor = old_gov;
2448                 if (cpufreq_init_governor(policy))
2449                         policy->governor = NULL;
2450                 else
2451                         cpufreq_start_governor(policy);
2452         }
2453 
2454         return ret;
2455 }
2456 
2457 /**
2458  * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2459  * @cpu: CPU to re-evaluate the policy for.
2460  *
2461  * Update the current frequency for the cpufreq policy of @cpu and use
2462  * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2463  * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2464  * for the policy in question, among other things.
2465  */
2466 void cpufreq_update_policy(unsigned int cpu)
2467 {
2468         struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2469 
2470         if (!policy)
2471                 return;
2472 
2473         /*
2474          * BIOS might change freq behind our back
2475          * -> ask driver for current freq and notify governors about a change
2476          */
2477         if (cpufreq_driver->get && has_target() &&
2478             (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2479                 goto unlock;
2480 
2481         refresh_frequency_limits(policy);
2482 
2483 unlock:
2484         cpufreq_cpu_release(policy);
2485 }
2486 EXPORT_SYMBOL(cpufreq_update_policy);
2487 
2488 /**
2489  * cpufreq_update_limits - Update policy limits for a given CPU.
2490  * @cpu: CPU to update the policy limits for.
2491  *
2492  * Invoke the driver's ->update_limits callback if present or call
2493  * cpufreq_update_policy() for @cpu.
2494  */
2495 void cpufreq_update_limits(unsigned int cpu)
2496 {
2497         if (cpufreq_driver->update_limits)
2498                 cpufreq_driver->update_limits(cpu);
2499         else
2500                 cpufreq_update_policy(cpu);
2501 }
2502 EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2503 
2504 /*********************************************************************
2505  *               BOOST                                               *
2506  *********************************************************************/
2507 static int cpufreq_boost_set_sw(int state)
2508 {
2509         struct cpufreq_policy *policy;
2510 
2511         for_each_active_policy(policy) {
2512                 int ret;
2513 
2514                 if (!policy->freq_table)
2515                         return -ENXIO;
2516 
2517                 ret = cpufreq_frequency_table_cpuinfo(policy,
2518                                                       policy->freq_table);
2519                 if (ret) {
2520                         pr_err("%s: Policy frequency update failed\n",
2521                                __func__);
2522                         return ret;
2523                 }
2524 
2525                 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2526                 if (ret < 0)
2527                         return ret;
2528         }
2529 
2530         return 0;
2531 }
2532 
2533 int cpufreq_boost_trigger_state(int state)
2534 {
2535         unsigned long flags;
2536         int ret = 0;
2537 
2538         if (cpufreq_driver->boost_enabled == state)
2539                 return 0;
2540 
2541         write_lock_irqsave(&cpufreq_driver_lock, flags);
2542         cpufreq_driver->boost_enabled = state;
2543         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2544 
2545         ret = cpufreq_driver->set_boost(state);
2546         if (ret) {
2547                 write_lock_irqsave(&cpufreq_driver_lock, flags);
2548                 cpufreq_driver->boost_enabled = !state;
2549                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2550 
2551                 pr_err("%s: Cannot %s BOOST\n",
2552                        __func__, state ? "enable" : "disable");
2553         }
2554 
2555         return ret;
2556 }
2557 
2558 static bool cpufreq_boost_supported(void)
2559 {
2560         return cpufreq_driver->set_boost;
2561 }
2562 
2563 static int create_boost_sysfs_file(void)
2564 {
2565         int ret;
2566 
2567         ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2568         if (ret)
2569                 pr_err("%s: cannot register global BOOST sysfs file\n",
2570                        __func__);
2571 
2572         return ret;
2573 }
2574 
2575 static void remove_boost_sysfs_file(void)
2576 {
2577         if (cpufreq_boost_supported())
2578                 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2579 }
2580 
2581 int cpufreq_enable_boost_support(void)
2582 {
2583         if (!cpufreq_driver)
2584                 return -EINVAL;
2585 
2586         if (cpufreq_boost_supported())
2587                 return 0;
2588 
2589         cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2590 
2591         /* This will get removed on driver unregister */
2592         return create_boost_sysfs_file();
2593 }
2594 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2595 
2596 int cpufreq_boost_enabled(void)
2597 {
2598         return cpufreq_driver->boost_enabled;
2599 }
2600 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2601 
2602 /*********************************************************************
2603  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2604  *********************************************************************/
2605 static enum cpuhp_state hp_online;
2606 
2607 static int cpuhp_cpufreq_online(unsigned int cpu)
2608 {
2609         cpufreq_online(cpu);
2610 
2611         return 0;
2612 }
2613 
2614 static int cpuhp_cpufreq_offline(unsigned int cpu)
2615 {
2616         cpufreq_offline(cpu);
2617 
2618         return 0;
2619 }
2620 
2621 /**
2622  * cpufreq_register_driver - register a CPU Frequency driver
2623  * @driver_data: A struct cpufreq_driver containing the values#
2624  * submitted by the CPU Frequency driver.
2625  *
2626  * Registers a CPU Frequency driver to this core code. This code
2627  * returns zero on success, -EEXIST when another driver got here first
2628  * (and isn't unregistered in the meantime).
2629  *
2630  */
2631 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2632 {
2633         unsigned long flags;
2634         int ret;
2635 
2636         if (cpufreq_disabled())
2637                 return -ENODEV;
2638 
2639         /*
2640          * The cpufreq core depends heavily on the availability of device
2641          * structure, make sure they are available before proceeding further.
2642          */
2643         if (!get_cpu_device(0))
2644                 return -EPROBE_DEFER;
2645 
2646         if (!driver_data || !driver_data->verify || !driver_data->init ||
2647             !(driver_data->setpolicy || driver_data->target_index ||
2648                     driver_data->target) ||
2649              (driver_data->setpolicy && (driver_data->target_index ||
2650                     driver_data->target)) ||
2651              (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2652              (!driver_data->online != !driver_data->offline))
2653                 return -EINVAL;
2654 
2655         pr_debug("trying to register driver %s\n", driver_data->name);
2656 
2657         /* Protect against concurrent CPU online/offline. */
2658         cpus_read_lock();
2659 
2660         write_lock_irqsave(&cpufreq_driver_lock, flags);
2661         if (cpufreq_driver) {
2662                 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2663                 ret = -EEXIST;
2664                 goto out;
2665         }
2666         cpufreq_driver = driver_data;
2667         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2668 
2669         if (driver_data->setpolicy)
2670                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2671 
2672         if (cpufreq_boost_supported()) {
2673                 ret = create_boost_sysfs_file();
2674                 if (ret)
2675                         goto err_null_driver;
2676         }
2677 
2678         ret = subsys_interface_register(&cpufreq_interface);
2679         if (ret)
2680                 goto err_boost_unreg;
2681 
2682         if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2683             list_empty(&cpufreq_policy_list)) {
2684                 /* if all ->init() calls failed, unregister */
2685                 ret = -ENODEV;
2686                 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2687                          driver_data->name);
2688                 goto err_if_unreg;
2689         }
2690 
2691         ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2692                                                    "cpufreq:online",
2693                                                    cpuhp_cpufreq_online,
2694                                                    cpuhp_cpufreq_offline);
2695         if (ret < 0)
2696                 goto err_if_unreg;
2697         hp_online = ret;
2698         ret = 0;
2699 
2700         pr_debug("driver %s up and running\n", driver_data->name);
2701         goto out;
2702 
2703 err_if_unreg:
2704         subsys_interface_unregister(&cpufreq_interface);
2705 err_boost_unreg:
2706         remove_boost_sysfs_file();
2707 err_null_driver:
2708         write_lock_irqsave(&cpufreq_driver_lock, flags);
2709         cpufreq_driver = NULL;
2710         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2711 out:
2712         cpus_read_unlock();
2713         return ret;
2714 }
2715 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2716 
2717 /**
2718  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2719  *
2720  * Unregister the current CPUFreq driver. Only call this if you have
2721  * the right to do so, i.e. if you have succeeded in initialising before!
2722  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2723  * currently not initialised.
2724  */
2725 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2726 {
2727         unsigned long flags;
2728 
2729         if (!cpufreq_driver || (driver != cpufreq_driver))
2730                 return -EINVAL;
2731 
2732         pr_debug("unregistering driver %s\n", driver->name);
2733 
2734         /* Protect against concurrent cpu hotplug */
2735         cpus_read_lock();
2736         subsys_interface_unregister(&cpufreq_interface);
2737         remove_boost_sysfs_file();
2738         cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2739 
2740         write_lock_irqsave(&cpufreq_driver_lock, flags);
2741 
2742         cpufreq_driver = NULL;
2743 
2744         write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2745         cpus_read_unlock();
2746 
2747         return 0;
2748 }
2749 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2750 
2751 struct kobject *cpufreq_global_kobject;
2752 EXPORT_SYMBOL(cpufreq_global_kobject);
2753 
2754 static int __init cpufreq_core_init(void)
2755 {
2756         if (cpufreq_disabled())
2757                 return -ENODEV;
2758 
2759         cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2760         BUG_ON(!cpufreq_global_kobject);
2761 
2762         return 0;
2763 }
2764 module_param(off, int, 0444);
2765 core_initcall(cpufreq_core_init);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/cpufreq/cpufreq.c

DEFINITIONS
