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