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_cputime64(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 = cputime_to_usecs(cur_wall_time); 147 148 return cputime_to_usecs(idle_time); 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 /********************************************************************* 528 * SYSFS INTERFACE * 529 *********************************************************************/ 530 static ssize_t show_boost(struct kobject *kobj, 531 struct attribute *attr, char *buf) 532 { 533 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled); 534 } 535 536 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr, 537 const char *buf, size_t count) 538 { 539 int ret, enable; 540 541 ret = sscanf(buf, "%d", &enable); 542 if (ret != 1 || enable < 0 || enable > 1) 543 return -EINVAL; 544 545 if (cpufreq_boost_trigger_state(enable)) { 546 pr_err("%s: Cannot %s BOOST!\n", 547 __func__, enable ? "enable" : "disable"); 548 return -EINVAL; 549 } 550 551 pr_debug("%s: cpufreq BOOST %s\n", 552 __func__, enable ? "enabled" : "disabled"); 553 554 return count; 555 } 556 define_one_global_rw(boost); 557 558 static struct cpufreq_governor *find_governor(const char *str_governor) 559 { 560 struct cpufreq_governor *t; 561 562 for_each_governor(t) 563 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN)) 564 return t; 565 566 return NULL; 567 } 568 569 /** 570 * cpufreq_parse_governor - parse a governor string 571 */ 572 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, 573 struct cpufreq_governor **governor) 574 { 575 int err = -EINVAL; 576 577 if (cpufreq_driver->setpolicy) { 578 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { 579 *policy = CPUFREQ_POLICY_PERFORMANCE; 580 err = 0; 581 } else if (!strncasecmp(str_governor, "powersave", 582 CPUFREQ_NAME_LEN)) { 583 *policy = CPUFREQ_POLICY_POWERSAVE; 584 err = 0; 585 } 586 } else { 587 struct cpufreq_governor *t; 588 589 mutex_lock(&cpufreq_governor_mutex); 590 591 t = find_governor(str_governor); 592 593 if (t == NULL) { 594 int ret; 595 596 mutex_unlock(&cpufreq_governor_mutex); 597 ret = request_module("cpufreq_%s", str_governor); 598 mutex_lock(&cpufreq_governor_mutex); 599 600 if (ret == 0) 601 t = find_governor(str_governor); 602 } 603 604 if (t != NULL) { 605 *governor = t; 606 err = 0; 607 } 608 609 mutex_unlock(&cpufreq_governor_mutex); 610 } 611 return err; 612 } 613 614 /** 615 * cpufreq_per_cpu_attr_read() / show_##file_name() - 616 * print out cpufreq information 617 * 618 * Write out information from cpufreq_driver->policy[cpu]; object must be 619 * "unsigned int". 620 */ 621 622 #define show_one(file_name, object) \ 623 static ssize_t show_##file_name \ 624 (struct cpufreq_policy *policy, char *buf) \ 625 { \ 626 return sprintf(buf, "%u\n", policy->object); \ 627 } 628 629 show_one(cpuinfo_min_freq, cpuinfo.min_freq); 630 show_one(cpuinfo_max_freq, cpuinfo.max_freq); 631 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); 632 show_one(scaling_min_freq, min); 633 show_one(scaling_max_freq, max); 634 635 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) 636 { 637 ssize_t ret; 638 639 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) 640 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu)); 641 else 642 ret = sprintf(buf, "%u\n", policy->cur); 643 return ret; 644 } 645 646 static int cpufreq_set_policy(struct cpufreq_policy *policy, 647 struct cpufreq_policy *new_policy); 648 649 /** 650 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access 651 */ 652 #define store_one(file_name, object) \ 653 static ssize_t store_##file_name \ 654 (struct cpufreq_policy *policy, const char *buf, size_t count) \ 655 { \ 656 int ret, temp; \ 657 struct cpufreq_policy new_policy; \ 658 \ 659 memcpy(&new_policy, policy, sizeof(*policy)); \ 660 \ 661 ret = sscanf(buf, "%u", &new_policy.object); \ 662 if (ret != 1) \ 663 return -EINVAL; \ 664 \ 665 temp = new_policy.object; \ 666 ret = cpufreq_set_policy(policy, &new_policy); \ 667 if (!ret) \ 668 policy->user_policy.object = temp; \ 669 \ 670 return ret ? ret : count; \ 671 } 672 673 store_one(scaling_min_freq, min); 674 store_one(scaling_max_freq, max); 675 676 /** 677 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware 678 */ 679 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, 680 char *buf) 681 { 682 unsigned int cur_freq = __cpufreq_get(policy); 683 if (!cur_freq) 684 return sprintf(buf, "<unknown>"); 685 return sprintf(buf, "%u\n", cur_freq); 686 } 687 688 /** 689 * show_scaling_governor - show the current policy for the specified CPU 690 */ 691 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) 692 { 693 if (policy->policy == CPUFREQ_POLICY_POWERSAVE) 694 return sprintf(buf, "powersave\n"); 695 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) 696 return sprintf(buf, "performance\n"); 697 else if (policy->governor) 698 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", 699 policy->governor->name); 700 return -EINVAL; 701 } 702 703 /** 704 * store_scaling_governor - store policy for the specified CPU 705 */ 706 static ssize_t store_scaling_governor(struct cpufreq_policy *policy, 707 const char *buf, size_t count) 708 { 709 int ret; 710 char str_governor[16]; 711 struct cpufreq_policy new_policy; 712 713 memcpy(&new_policy, policy, sizeof(*policy)); 714 715 ret = sscanf(buf, "%15s", str_governor); 716 if (ret != 1) 717 return -EINVAL; 718 719 if (cpufreq_parse_governor(str_governor, &new_policy.policy, 720 &new_policy.governor)) 721 return -EINVAL; 722 723 ret = cpufreq_set_policy(policy, &new_policy); 724 return ret ? ret : count; 725 } 726 727 /** 728 * show_scaling_driver - show the cpufreq driver currently loaded 729 */ 730 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) 731 { 732 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); 733 } 734 735 /** 736 * show_scaling_available_governors - show the available CPUfreq governors 737 */ 738 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, 739 char *buf) 740 { 741 ssize_t i = 0; 742 struct cpufreq_governor *t; 743 744 if (!has_target()) { 745 i += sprintf(buf, "performance powersave"); 746 goto out; 747 } 748 749 for_each_governor(t) { 750 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) 751 - (CPUFREQ_NAME_LEN + 2))) 752 goto out; 753 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); 754 } 755 out: 756 i += sprintf(&buf[i], "\n"); 757 return i; 758 } 759 760 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) 761 { 762 ssize_t i = 0; 763 unsigned int cpu; 764 765 for_each_cpu(cpu, mask) { 766 if (i) 767 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); 768 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); 769 if (i >= (PAGE_SIZE - 5)) 770 break; 771 } 772 i += sprintf(&buf[i], "\n"); 773 return i; 774 } 775 EXPORT_SYMBOL_GPL(cpufreq_show_cpus); 776 777 /** 778 * show_related_cpus - show the CPUs affected by each transition even if 779 * hw coordination is in use 780 */ 781 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) 782 { 783 return cpufreq_show_cpus(policy->related_cpus, buf); 784 } 785 786 /** 787 * show_affected_cpus - show the CPUs affected by each transition 788 */ 789 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) 790 { 791 return cpufreq_show_cpus(policy->cpus, buf); 792 } 793 794 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, 795 const char *buf, size_t count) 796 { 797 unsigned int freq = 0; 798 unsigned int ret; 799 800 if (!policy->governor || !policy->governor->store_setspeed) 801 return -EINVAL; 802 803 ret = sscanf(buf, "%u", &freq); 804 if (ret != 1) 805 return -EINVAL; 806 807 policy->governor->store_setspeed(policy, freq); 808 809 return count; 810 } 811 812 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) 813 { 814 if (!policy->governor || !policy->governor->show_setspeed) 815 return sprintf(buf, "<unsupported>\n"); 816 817 return policy->governor->show_setspeed(policy, buf); 818 } 819 820 /** 821 * show_bios_limit - show the current cpufreq HW/BIOS limitation 822 */ 823 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) 824 { 825 unsigned int limit; 826 int ret; 827 if (cpufreq_driver->bios_limit) { 828 ret = cpufreq_driver->bios_limit(policy->cpu, &limit); 829 if (!ret) 830 return sprintf(buf, "%u\n", limit); 831 } 832 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); 833 } 834 835 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); 836 cpufreq_freq_attr_ro(cpuinfo_min_freq); 837 cpufreq_freq_attr_ro(cpuinfo_max_freq); 838 cpufreq_freq_attr_ro(cpuinfo_transition_latency); 839 cpufreq_freq_attr_ro(scaling_available_governors); 840 cpufreq_freq_attr_ro(scaling_driver); 841 cpufreq_freq_attr_ro(scaling_cur_freq); 842 cpufreq_freq_attr_ro(bios_limit); 843 cpufreq_freq_attr_ro(related_cpus); 844 cpufreq_freq_attr_ro(affected_cpus); 845 cpufreq_freq_attr_rw(scaling_min_freq); 846 cpufreq_freq_attr_rw(scaling_max_freq); 847 cpufreq_freq_attr_rw(scaling_governor); 848 cpufreq_freq_attr_rw(scaling_setspeed); 849 850 static struct attribute *default_attrs[] = { 851 &cpuinfo_min_freq.attr, 852 &cpuinfo_max_freq.attr, 853 &cpuinfo_transition_latency.attr, 854 &scaling_min_freq.attr, 855 &scaling_max_freq.attr, 856 &affected_cpus.attr, 857 &related_cpus.attr, 858 &scaling_governor.attr, 859 &scaling_driver.attr, 860 &scaling_available_governors.attr, 861 &scaling_setspeed.attr, 862 NULL 863 }; 864 865 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) 866 #define to_attr(a) container_of(a, struct freq_attr, attr) 867 868 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) 869 { 870 struct cpufreq_policy *policy = to_policy(kobj); 871 struct freq_attr *fattr = to_attr(attr); 872 ssize_t ret; 873 874 down_read(&policy->rwsem); 875 ret = fattr->show(policy, buf); 876 up_read(&policy->rwsem); 877 878 return ret; 879 } 880 881 static ssize_t store(struct kobject *kobj, struct attribute *attr, 882 const char *buf, size_t count) 883 { 884 struct cpufreq_policy *policy = to_policy(kobj); 885 struct freq_attr *fattr = to_attr(attr); 886 ssize_t ret = -EINVAL; 887 888 get_online_cpus(); 889 890 if (cpu_online(policy->cpu)) { 891 down_write(&policy->rwsem); 892 ret = fattr->store(policy, buf, count); 893 up_write(&policy->rwsem); 894 } 895 896 put_online_cpus(); 897 898 return ret; 899 } 900 901 static void cpufreq_sysfs_release(struct kobject *kobj) 902 { 903 struct cpufreq_policy *policy = to_policy(kobj); 904 pr_debug("last reference is dropped\n"); 905 complete(&policy->kobj_unregister); 906 } 907 908 static const struct sysfs_ops sysfs_ops = { 909 .show = show, 910 .store = store, 911 }; 912 913 static struct kobj_type ktype_cpufreq = { 914 .sysfs_ops = &sysfs_ops, 915 .default_attrs = default_attrs, 916 .release = cpufreq_sysfs_release, 917 }; 918 919 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, 920 struct device *dev) 921 { 922 dev_dbg(dev, "%s: Adding symlink\n", __func__); 923 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); 924 } 925 926 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, 927 struct device *dev) 928 { 929 dev_dbg(dev, "%s: Removing symlink\n", __func__); 930 sysfs_remove_link(&dev->kobj, "cpufreq"); 931 } 932 933 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy) 934 { 935 struct freq_attr **drv_attr; 936 int ret = 0; 937 938 /* set up files for this cpu device */ 939 drv_attr = cpufreq_driver->attr; 940 while (drv_attr && *drv_attr) { 941 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); 942 if (ret) 943 return ret; 944 drv_attr++; 945 } 946 if (cpufreq_driver->get) { 947 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); 948 if (ret) 949 return ret; 950 } 951 952 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); 953 if (ret) 954 return ret; 955 956 if (cpufreq_driver->bios_limit) { 957 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); 958 if (ret) 959 return ret; 960 } 961 962 return 0; 963 } 964 965 __weak struct cpufreq_governor *cpufreq_default_governor(void) 966 { 967 return NULL; 968 } 969 970 static int cpufreq_init_policy(struct cpufreq_policy *policy) 971 { 972 struct cpufreq_governor *gov = NULL; 973 struct cpufreq_policy new_policy; 974 975 memcpy(&new_policy, policy, sizeof(*policy)); 976 977 /* Update governor of new_policy to the governor used before hotplug */ 978 gov = find_governor(policy->last_governor); 979 if (gov) { 980 pr_debug("Restoring governor %s for cpu %d\n", 981 policy->governor->name, policy->cpu); 982 } else { 983 gov = cpufreq_default_governor(); 984 if (!gov) 985 return -ENODATA; 986 } 987 988 new_policy.governor = gov; 989 990 /* Use the default policy if there is no last_policy. */ 991 if (cpufreq_driver->setpolicy) { 992 if (policy->last_policy) 993 new_policy.policy = policy->last_policy; 994 else 995 cpufreq_parse_governor(gov->name, &new_policy.policy, 996 NULL); 997 } 998 /* set default policy */ 999 return cpufreq_set_policy(policy, &new_policy); 1000 } 1001 1002 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) 1003 { 1004 int ret = 0; 1005 1006 /* Has this CPU been taken care of already? */ 1007 if (cpumask_test_cpu(cpu, policy->cpus)) 1008 return 0; 1009 1010 down_write(&policy->rwsem); 1011 if (has_target()) 1012 cpufreq_stop_governor(policy); 1013 1014 cpumask_set_cpu(cpu, policy->cpus); 1015 1016 if (has_target()) { 1017 ret = cpufreq_start_governor(policy); 1018 if (ret) 1019 pr_err("%s: Failed to start governor\n", __func__); 1020 } 1021 up_write(&policy->rwsem); 1022 return ret; 1023 } 1024 1025 static void handle_update(struct work_struct *work) 1026 { 1027 struct cpufreq_policy *policy = 1028 container_of(work, struct cpufreq_policy, update); 1029 unsigned int cpu = policy->cpu; 1030 pr_debug("handle_update for cpu %u called\n", cpu); 1031 cpufreq_update_policy(cpu); 1032 } 1033 1034 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu) 1035 { 1036 struct cpufreq_policy *policy; 1037 int ret; 1038 1039 policy = kzalloc(sizeof(*policy), GFP_KERNEL); 1040 if (!policy) 1041 return NULL; 1042 1043 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) 1044 goto err_free_policy; 1045 1046 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) 1047 goto err_free_cpumask; 1048 1049 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL)) 1050 goto err_free_rcpumask; 1051 1052 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, 1053 cpufreq_global_kobject, "policy%u", cpu); 1054 if (ret) { 1055 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret); 1056 goto err_free_real_cpus; 1057 } 1058 1059 INIT_LIST_HEAD(&policy->policy_list); 1060 init_rwsem(&policy->rwsem); 1061 spin_lock_init(&policy->transition_lock); 1062 init_waitqueue_head(&policy->transition_wait); 1063 init_completion(&policy->kobj_unregister); 1064 INIT_WORK(&policy->update, handle_update); 1065 1066 policy->cpu = cpu; 1067 return policy; 1068 1069 err_free_real_cpus: 1070 free_cpumask_var(policy->real_cpus); 1071 err_free_rcpumask: 1072 free_cpumask_var(policy->related_cpus); 1073 err_free_cpumask: 1074 free_cpumask_var(policy->cpus); 1075 err_free_policy: 1076 kfree(policy); 1077 1078 return NULL; 1079 } 1080 1081 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify) 1082 { 1083 struct kobject *kobj; 1084 struct completion *cmp; 1085 1086 if (notify) 1087 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1088 CPUFREQ_REMOVE_POLICY, policy); 1089 1090 down_write(&policy->rwsem); 1091 cpufreq_stats_free_table(policy); 1092 kobj = &policy->kobj; 1093 cmp = &policy->kobj_unregister; 1094 up_write(&policy->rwsem); 1095 kobject_put(kobj); 1096 1097 /* 1098 * We need to make sure that the underlying kobj is 1099 * actually not referenced anymore by anybody before we 1100 * proceed with unloading. 1101 */ 1102 pr_debug("waiting for dropping of refcount\n"); 1103 wait_for_completion(cmp); 1104 pr_debug("wait complete\n"); 1105 } 1106 1107 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify) 1108 { 1109 unsigned long flags; 1110 int cpu; 1111 1112 /* Remove policy from list */ 1113 write_lock_irqsave(&cpufreq_driver_lock, flags); 1114 list_del(&policy->policy_list); 1115 1116 for_each_cpu(cpu, policy->related_cpus) 1117 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1118 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1119 1120 cpufreq_policy_put_kobj(policy, notify); 1121 free_cpumask_var(policy->real_cpus); 1122 free_cpumask_var(policy->related_cpus); 1123 free_cpumask_var(policy->cpus); 1124 kfree(policy); 1125 } 1126 1127 static int cpufreq_online(unsigned int cpu) 1128 { 1129 struct cpufreq_policy *policy; 1130 bool new_policy; 1131 unsigned long flags; 1132 unsigned int j; 1133 int ret; 1134 1135 pr_debug("%s: bringing CPU%u online\n", __func__, cpu); 1136 1137 /* Check if this CPU already has a policy to manage it */ 1138 policy = per_cpu(cpufreq_cpu_data, cpu); 1139 if (policy) { 1140 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus)); 1141 if (!policy_is_inactive(policy)) 1142 return cpufreq_add_policy_cpu(policy, cpu); 1143 1144 /* This is the only online CPU for the policy. Start over. */ 1145 new_policy = false; 1146 down_write(&policy->rwsem); 1147 policy->cpu = cpu; 1148 policy->governor = NULL; 1149 up_write(&policy->rwsem); 1150 } else { 1151 new_policy = true; 1152 policy = cpufreq_policy_alloc(cpu); 1153 if (!policy) 1154 return -ENOMEM; 1155 } 1156 1157 cpumask_copy(policy->cpus, cpumask_of(cpu)); 1158 1159 /* call driver. From then on the cpufreq must be able 1160 * to accept all calls to ->verify and ->setpolicy for this CPU 1161 */ 1162 ret = cpufreq_driver->init(policy); 1163 if (ret) { 1164 pr_debug("initialization failed\n"); 1165 goto out_free_policy; 1166 } 1167 1168 down_write(&policy->rwsem); 1169 1170 if (new_policy) { 1171 /* related_cpus should at least include policy->cpus. */ 1172 cpumask_copy(policy->related_cpus, policy->cpus); 1173 /* Clear mask of registered CPUs */ 1174 cpumask_clear(policy->real_cpus); 1175 } 1176 1177 /* 1178 * affected cpus must always be the one, which are online. We aren't 1179 * managing offline cpus here. 1180 */ 1181 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); 1182 1183 if (new_policy) { 1184 policy->user_policy.min = policy->min; 1185 policy->user_policy.max = policy->max; 1186 1187 write_lock_irqsave(&cpufreq_driver_lock, flags); 1188 for_each_cpu(j, policy->related_cpus) 1189 per_cpu(cpufreq_cpu_data, j) = policy; 1190 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1191 } 1192 1193 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 1194 policy->cur = cpufreq_driver->get(policy->cpu); 1195 if (!policy->cur) { 1196 pr_err("%s: ->get() failed\n", __func__); 1197 goto out_exit_policy; 1198 } 1199 } 1200 1201 /* 1202 * Sometimes boot loaders set CPU frequency to a value outside of 1203 * frequency table present with cpufreq core. In such cases CPU might be 1204 * unstable if it has to run on that frequency for long duration of time 1205 * and so its better to set it to a frequency which is specified in 1206 * freq-table. This also makes cpufreq stats inconsistent as 1207 * cpufreq-stats would fail to register because current frequency of CPU 1208 * isn't found in freq-table. 1209 * 1210 * Because we don't want this change to effect boot process badly, we go 1211 * for the next freq which is >= policy->cur ('cur' must be set by now, 1212 * otherwise we will end up setting freq to lowest of the table as 'cur' 1213 * is initialized to zero). 1214 * 1215 * We are passing target-freq as "policy->cur - 1" otherwise 1216 * __cpufreq_driver_target() would simply fail, as policy->cur will be 1217 * equal to target-freq. 1218 */ 1219 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) 1220 && has_target()) { 1221 /* Are we running at unknown frequency ? */ 1222 ret = cpufreq_frequency_table_get_index(policy, policy->cur); 1223 if (ret == -EINVAL) { 1224 /* Warn user and fix it */ 1225 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", 1226 __func__, policy->cpu, policy->cur); 1227 ret = __cpufreq_driver_target(policy, policy->cur - 1, 1228 CPUFREQ_RELATION_L); 1229 1230 /* 1231 * Reaching here after boot in a few seconds may not 1232 * mean that system will remain stable at "unknown" 1233 * frequency for longer duration. Hence, a BUG_ON(). 1234 */ 1235 BUG_ON(ret); 1236 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", 1237 __func__, policy->cpu, policy->cur); 1238 } 1239 } 1240 1241 if (new_policy) { 1242 ret = cpufreq_add_dev_interface(policy); 1243 if (ret) 1244 goto out_exit_policy; 1245 1246 cpufreq_stats_create_table(policy); 1247 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1248 CPUFREQ_CREATE_POLICY, policy); 1249 1250 write_lock_irqsave(&cpufreq_driver_lock, flags); 1251 list_add(&policy->policy_list, &cpufreq_policy_list); 1252 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1253 } 1254 1255 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1256 CPUFREQ_START, policy); 1257 1258 ret = cpufreq_init_policy(policy); 1259 if (ret) { 1260 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n", 1261 __func__, cpu, ret); 1262 /* cpufreq_policy_free() will notify based on this */ 1263 new_policy = false; 1264 goto out_exit_policy; 1265 } 1266 1267 up_write(&policy->rwsem); 1268 1269 kobject_uevent(&policy->kobj, KOBJ_ADD); 1270 1271 /* Callback for handling stuff after policy is ready */ 1272 if (cpufreq_driver->ready) 1273 cpufreq_driver->ready(policy); 1274 1275 pr_debug("initialization complete\n"); 1276 1277 return 0; 1278 1279 out_exit_policy: 1280 up_write(&policy->rwsem); 1281 1282 if (cpufreq_driver->exit) 1283 cpufreq_driver->exit(policy); 1284 out_free_policy: 1285 cpufreq_policy_free(policy, !new_policy); 1286 return ret; 1287 } 1288 1289 static int cpufreq_offline(unsigned int cpu); 1290 1291 /** 1292 * cpufreq_add_dev - the cpufreq interface for a CPU device. 1293 * @dev: CPU device. 1294 * @sif: Subsystem interface structure pointer (not used) 1295 */ 1296 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1297 { 1298 struct cpufreq_policy *policy; 1299 unsigned cpu = dev->id; 1300 int ret; 1301 1302 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu); 1303 1304 if (cpu_online(cpu)) { 1305 ret = cpufreq_online(cpu); 1306 if (ret) 1307 return ret; 1308 } 1309 1310 /* Create sysfs link on CPU registration */ 1311 policy = per_cpu(cpufreq_cpu_data, cpu); 1312 if (!policy || cpumask_test_and_set_cpu(cpu, policy->real_cpus)) 1313 return 0; 1314 1315 ret = add_cpu_dev_symlink(policy, dev); 1316 if (ret) { 1317 cpumask_clear_cpu(cpu, policy->real_cpus); 1318 cpufreq_offline(cpu); 1319 } 1320 1321 return ret; 1322 } 1323 1324 static int cpufreq_offline(unsigned int cpu) 1325 { 1326 struct cpufreq_policy *policy; 1327 int ret; 1328 1329 pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 1330 1331 policy = cpufreq_cpu_get_raw(cpu); 1332 if (!policy) { 1333 pr_debug("%s: No cpu_data found\n", __func__); 1334 return 0; 1335 } 1336 1337 down_write(&policy->rwsem); 1338 if (has_target()) 1339 cpufreq_stop_governor(policy); 1340 1341 cpumask_clear_cpu(cpu, policy->cpus); 1342 1343 if (policy_is_inactive(policy)) { 1344 if (has_target()) 1345 strncpy(policy->last_governor, policy->governor->name, 1346 CPUFREQ_NAME_LEN); 1347 else 1348 policy->last_policy = policy->policy; 1349 } else if (cpu == policy->cpu) { 1350 /* Nominate new CPU */ 1351 policy->cpu = cpumask_any(policy->cpus); 1352 } 1353 1354 /* Start governor again for active policy */ 1355 if (!policy_is_inactive(policy)) { 1356 if (has_target()) { 1357 ret = cpufreq_start_governor(policy); 1358 if (ret) 1359 pr_err("%s: Failed to start governor\n", __func__); 1360 } 1361 1362 goto unlock; 1363 } 1364 1365 if (cpufreq_driver->stop_cpu) 1366 cpufreq_driver->stop_cpu(policy); 1367 1368 if (has_target()) 1369 cpufreq_exit_governor(policy); 1370 1371 /* 1372 * Perform the ->exit() even during light-weight tear-down, 1373 * since this is a core component, and is essential for the 1374 * subsequent light-weight ->init() to succeed. 1375 */ 1376 if (cpufreq_driver->exit) { 1377 cpufreq_driver->exit(policy); 1378 policy->freq_table = NULL; 1379 } 1380 1381 unlock: 1382 up_write(&policy->rwsem); 1383 return 0; 1384 } 1385 1386 /** 1387 * cpufreq_remove_dev - remove a CPU device 1388 * 1389 * Removes the cpufreq interface for a CPU device. 1390 */ 1391 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 1392 { 1393 unsigned int cpu = dev->id; 1394 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1395 1396 if (!policy) 1397 return; 1398 1399 if (cpu_online(cpu)) 1400 cpufreq_offline(cpu); 1401 1402 cpumask_clear_cpu(cpu, policy->real_cpus); 1403 remove_cpu_dev_symlink(policy, dev); 1404 1405 if (cpumask_empty(policy->real_cpus)) 1406 cpufreq_policy_free(policy, true); 1407 } 1408 1409 /** 1410 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're 1411 * in deep trouble. 1412 * @policy: policy managing CPUs 1413 * @new_freq: CPU frequency the CPU actually runs at 1414 * 1415 * We adjust to current frequency first, and need to clean up later. 1416 * So either call to cpufreq_update_policy() or schedule handle_update()). 1417 */ 1418 static void cpufreq_out_of_sync(struct cpufreq_policy *policy, 1419 unsigned int new_freq) 1420 { 1421 struct cpufreq_freqs freqs; 1422 1423 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n", 1424 policy->cur, new_freq); 1425 1426 freqs.old = policy->cur; 1427 freqs.new = new_freq; 1428 1429 cpufreq_freq_transition_begin(policy, &freqs); 1430 cpufreq_freq_transition_end(policy, &freqs, 0); 1431 } 1432 1433 /** 1434 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1435 * @cpu: CPU number 1436 * 1437 * This is the last known freq, without actually getting it from the driver. 1438 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1439 */ 1440 unsigned int cpufreq_quick_get(unsigned int cpu) 1441 { 1442 struct cpufreq_policy *policy; 1443 unsigned int ret_freq = 0; 1444 unsigned long flags; 1445 1446 read_lock_irqsave(&cpufreq_driver_lock, flags); 1447 1448 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) { 1449 ret_freq = cpufreq_driver->get(cpu); 1450 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1451 return ret_freq; 1452 } 1453 1454 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1455 1456 policy = cpufreq_cpu_get(cpu); 1457 if (policy) { 1458 ret_freq = policy->cur; 1459 cpufreq_cpu_put(policy); 1460 } 1461 1462 return ret_freq; 1463 } 1464 EXPORT_SYMBOL(cpufreq_quick_get); 1465 1466 /** 1467 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU 1468 * @cpu: CPU number 1469 * 1470 * Just return the max possible frequency for a given CPU. 1471 */ 1472 unsigned int cpufreq_quick_get_max(unsigned int cpu) 1473 { 1474 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1475 unsigned int ret_freq = 0; 1476 1477 if (policy) { 1478 ret_freq = policy->max; 1479 cpufreq_cpu_put(policy); 1480 } 1481 1482 return ret_freq; 1483 } 1484 EXPORT_SYMBOL(cpufreq_quick_get_max); 1485 1486 static unsigned int __cpufreq_get(struct cpufreq_policy *policy) 1487 { 1488 unsigned int ret_freq = 0; 1489 1490 if (!cpufreq_driver->get) 1491 return ret_freq; 1492 1493 ret_freq = cpufreq_driver->get(policy->cpu); 1494 1495 /* 1496 * Updating inactive policies is invalid, so avoid doing that. Also 1497 * if fast frequency switching is used with the given policy, the check 1498 * against policy->cur is pointless, so skip it in that case too. 1499 */ 1500 if (unlikely(policy_is_inactive(policy)) || policy->fast_switch_enabled) 1501 return ret_freq; 1502 1503 if (ret_freq && policy->cur && 1504 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1505 /* verify no discrepancy between actual and 1506 saved value exists */ 1507 if (unlikely(ret_freq != policy->cur)) { 1508 cpufreq_out_of_sync(policy, ret_freq); 1509 schedule_work(&policy->update); 1510 } 1511 } 1512 1513 return ret_freq; 1514 } 1515 1516 /** 1517 * cpufreq_get - get the current CPU frequency (in kHz) 1518 * @cpu: CPU number 1519 * 1520 * Get the CPU current (static) CPU frequency 1521 */ 1522 unsigned int cpufreq_get(unsigned int cpu) 1523 { 1524 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1525 unsigned int ret_freq = 0; 1526 1527 if (policy) { 1528 down_read(&policy->rwsem); 1529 ret_freq = __cpufreq_get(policy); 1530 up_read(&policy->rwsem); 1531 1532 cpufreq_cpu_put(policy); 1533 } 1534 1535 return ret_freq; 1536 } 1537 EXPORT_SYMBOL(cpufreq_get); 1538 1539 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy) 1540 { 1541 unsigned int new_freq; 1542 1543 new_freq = cpufreq_driver->get(policy->cpu); 1544 if (!new_freq) 1545 return 0; 1546 1547 if (!policy->cur) { 1548 pr_debug("cpufreq: Driver did not initialize current freq\n"); 1549 policy->cur = new_freq; 1550 } else if (policy->cur != new_freq && has_target()) { 1551 cpufreq_out_of_sync(policy, new_freq); 1552 } 1553 1554 return new_freq; 1555 } 1556 1557 static struct subsys_interface cpufreq_interface = { 1558 .name = "cpufreq", 1559 .subsys = &cpu_subsys, 1560 .add_dev = cpufreq_add_dev, 1561 .remove_dev = cpufreq_remove_dev, 1562 }; 1563 1564 /* 1565 * In case platform wants some specific frequency to be configured 1566 * during suspend.. 1567 */ 1568 int cpufreq_generic_suspend(struct cpufreq_policy *policy) 1569 { 1570 int ret; 1571 1572 if (!policy->suspend_freq) { 1573 pr_debug("%s: suspend_freq not defined\n", __func__); 1574 return 0; 1575 } 1576 1577 pr_debug("%s: Setting suspend-freq: %u\n", __func__, 1578 policy->suspend_freq); 1579 1580 ret = __cpufreq_driver_target(policy, policy->suspend_freq, 1581 CPUFREQ_RELATION_H); 1582 if (ret) 1583 pr_err("%s: unable to set suspend-freq: %u. err: %d\n", 1584 __func__, policy->suspend_freq, ret); 1585 1586 return ret; 1587 } 1588 EXPORT_SYMBOL(cpufreq_generic_suspend); 1589 1590 /** 1591 * cpufreq_suspend() - Suspend CPUFreq governors 1592 * 1593 * Called during system wide Suspend/Hibernate cycles for suspending governors 1594 * as some platforms can't change frequency after this point in suspend cycle. 1595 * Because some of the devices (like: i2c, regulators, etc) they use for 1596 * changing frequency are suspended quickly after this point. 1597 */ 1598 void cpufreq_suspend(void) 1599 { 1600 struct cpufreq_policy *policy; 1601 1602 if (!cpufreq_driver) 1603 return; 1604 1605 if (!has_target() && !cpufreq_driver->suspend) 1606 goto suspend; 1607 1608 pr_debug("%s: Suspending Governors\n", __func__); 1609 1610 for_each_active_policy(policy) { 1611 if (has_target()) { 1612 down_write(&policy->rwsem); 1613 cpufreq_stop_governor(policy); 1614 up_write(&policy->rwsem); 1615 } 1616 1617 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy)) 1618 pr_err("%s: Failed to suspend driver: %p\n", __func__, 1619 policy); 1620 } 1621 1622 suspend: 1623 cpufreq_suspended = true; 1624 } 1625 1626 /** 1627 * cpufreq_resume() - Resume CPUFreq governors 1628 * 1629 * Called during system wide Suspend/Hibernate cycle for resuming governors that 1630 * are suspended with cpufreq_suspend(). 1631 */ 1632 void cpufreq_resume(void) 1633 { 1634 struct cpufreq_policy *policy; 1635 int ret; 1636 1637 if (!cpufreq_driver) 1638 return; 1639 1640 cpufreq_suspended = false; 1641 1642 if (!has_target() && !cpufreq_driver->resume) 1643 return; 1644 1645 pr_debug("%s: Resuming Governors\n", __func__); 1646 1647 for_each_active_policy(policy) { 1648 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) { 1649 pr_err("%s: Failed to resume driver: %p\n", __func__, 1650 policy); 1651 } else if (has_target()) { 1652 down_write(&policy->rwsem); 1653 ret = cpufreq_start_governor(policy); 1654 up_write(&policy->rwsem); 1655 1656 if (ret) 1657 pr_err("%s: Failed to start governor for policy: %p\n", 1658 __func__, policy); 1659 } 1660 } 1661 } 1662 1663 /** 1664 * cpufreq_get_current_driver - return current driver's name 1665 * 1666 * Return the name string of the currently loaded cpufreq driver 1667 * or NULL, if none. 1668 */ 1669 const char *cpufreq_get_current_driver(void) 1670 { 1671 if (cpufreq_driver) 1672 return cpufreq_driver->name; 1673 1674 return NULL; 1675 } 1676 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); 1677 1678 /** 1679 * cpufreq_get_driver_data - return current driver data 1680 * 1681 * Return the private data of the currently loaded cpufreq 1682 * driver, or NULL if no cpufreq driver is loaded. 1683 */ 1684 void *cpufreq_get_driver_data(void) 1685 { 1686 if (cpufreq_driver) 1687 return cpufreq_driver->driver_data; 1688 1689 return NULL; 1690 } 1691 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data); 1692 1693 /********************************************************************* 1694 * NOTIFIER LISTS INTERFACE * 1695 *********************************************************************/ 1696 1697 /** 1698 * cpufreq_register_notifier - register a driver with cpufreq 1699 * @nb: notifier function to register 1700 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1701 * 1702 * Add a driver to one of two lists: either a list of drivers that 1703 * are notified about clock rate changes (once before and once after 1704 * the transition), or a list of drivers that are notified about 1705 * changes in cpufreq policy. 1706 * 1707 * This function may sleep, and has the same return conditions as 1708 * blocking_notifier_chain_register. 1709 */ 1710 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1711 { 1712 int ret; 1713 1714 if (cpufreq_disabled()) 1715 return -EINVAL; 1716 1717 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1718 1719 switch (list) { 1720 case CPUFREQ_TRANSITION_NOTIFIER: 1721 mutex_lock(&cpufreq_fast_switch_lock); 1722 1723 if (cpufreq_fast_switch_count > 0) { 1724 mutex_unlock(&cpufreq_fast_switch_lock); 1725 return -EBUSY; 1726 } 1727 ret = srcu_notifier_chain_register( 1728 &cpufreq_transition_notifier_list, nb); 1729 if (!ret) 1730 cpufreq_fast_switch_count--; 1731 1732 mutex_unlock(&cpufreq_fast_switch_lock); 1733 break; 1734 case CPUFREQ_POLICY_NOTIFIER: 1735 ret = blocking_notifier_chain_register( 1736 &cpufreq_policy_notifier_list, nb); 1737 break; 1738 default: 1739 ret = -EINVAL; 1740 } 1741 1742 return ret; 1743 } 1744 EXPORT_SYMBOL(cpufreq_register_notifier); 1745 1746 /** 1747 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1748 * @nb: notifier block to be unregistered 1749 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1750 * 1751 * Remove a driver from the CPU frequency notifier list. 1752 * 1753 * This function may sleep, and has the same return conditions as 1754 * blocking_notifier_chain_unregister. 1755 */ 1756 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1757 { 1758 int ret; 1759 1760 if (cpufreq_disabled()) 1761 return -EINVAL; 1762 1763 switch (list) { 1764 case CPUFREQ_TRANSITION_NOTIFIER: 1765 mutex_lock(&cpufreq_fast_switch_lock); 1766 1767 ret = srcu_notifier_chain_unregister( 1768 &cpufreq_transition_notifier_list, nb); 1769 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0)) 1770 cpufreq_fast_switch_count++; 1771 1772 mutex_unlock(&cpufreq_fast_switch_lock); 1773 break; 1774 case CPUFREQ_POLICY_NOTIFIER: 1775 ret = blocking_notifier_chain_unregister( 1776 &cpufreq_policy_notifier_list, nb); 1777 break; 1778 default: 1779 ret = -EINVAL; 1780 } 1781 1782 return ret; 1783 } 1784 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1785 1786 1787 /********************************************************************* 1788 * GOVERNORS * 1789 *********************************************************************/ 1790 1791 /** 1792 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch. 1793 * @policy: cpufreq policy to switch the frequency for. 1794 * @target_freq: New frequency to set (may be approximate). 1795 * 1796 * Carry out a fast frequency switch without sleeping. 1797 * 1798 * The driver's ->fast_switch() callback invoked by this function must be 1799 * suitable for being called from within RCU-sched read-side critical sections 1800 * and it is expected to select the minimum available frequency greater than or 1801 * equal to @target_freq (CPUFREQ_RELATION_L). 1802 * 1803 * This function must not be called if policy->fast_switch_enabled is unset. 1804 * 1805 * Governors calling this function must guarantee that it will never be invoked 1806 * twice in parallel for the same policy and that it will never be called in 1807 * parallel with either ->target() or ->target_index() for the same policy. 1808 * 1809 * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch() 1810 * callback to indicate an error condition, the hardware configuration must be 1811 * preserved. 1812 */ 1813 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy, 1814 unsigned int target_freq) 1815 { 1816 target_freq = clamp_val(target_freq, policy->min, policy->max); 1817 1818 return cpufreq_driver->fast_switch(policy, target_freq); 1819 } 1820 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch); 1821 1822 /* Must set freqs->new to intermediate frequency */ 1823 static int __target_intermediate(struct cpufreq_policy *policy, 1824 struct cpufreq_freqs *freqs, int index) 1825 { 1826 int ret; 1827 1828 freqs->new = cpufreq_driver->get_intermediate(policy, index); 1829 1830 /* We don't need to switch to intermediate freq */ 1831 if (!freqs->new) 1832 return 0; 1833 1834 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", 1835 __func__, policy->cpu, freqs->old, freqs->new); 1836 1837 cpufreq_freq_transition_begin(policy, freqs); 1838 ret = cpufreq_driver->target_intermediate(policy, index); 1839 cpufreq_freq_transition_end(policy, freqs, ret); 1840 1841 if (ret) 1842 pr_err("%s: Failed to change to intermediate frequency: %d\n", 1843 __func__, ret); 1844 1845 return ret; 1846 } 1847 1848 static int __target_index(struct cpufreq_policy *policy, int index) 1849 { 1850 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; 1851 unsigned int intermediate_freq = 0; 1852 unsigned int newfreq = policy->freq_table[index].frequency; 1853 int retval = -EINVAL; 1854 bool notify; 1855 1856 if (newfreq == policy->cur) 1857 return 0; 1858 1859 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); 1860 if (notify) { 1861 /* Handle switching to intermediate frequency */ 1862 if (cpufreq_driver->get_intermediate) { 1863 retval = __target_intermediate(policy, &freqs, index); 1864 if (retval) 1865 return retval; 1866 1867 intermediate_freq = freqs.new; 1868 /* Set old freq to intermediate */ 1869 if (intermediate_freq) 1870 freqs.old = freqs.new; 1871 } 1872 1873 freqs.new = newfreq; 1874 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", 1875 __func__, policy->cpu, freqs.old, freqs.new); 1876 1877 cpufreq_freq_transition_begin(policy, &freqs); 1878 } 1879 1880 retval = cpufreq_driver->target_index(policy, index); 1881 if (retval) 1882 pr_err("%s: Failed to change cpu frequency: %d\n", __func__, 1883 retval); 1884 1885 if (notify) { 1886 cpufreq_freq_transition_end(policy, &freqs, retval); 1887 1888 /* 1889 * Failed after setting to intermediate freq? Driver should have 1890 * reverted back to initial frequency and so should we. Check 1891 * here for intermediate_freq instead of get_intermediate, in 1892 * case we haven't switched to intermediate freq at all. 1893 */ 1894 if (unlikely(retval && intermediate_freq)) { 1895 freqs.old = intermediate_freq; 1896 freqs.new = policy->restore_freq; 1897 cpufreq_freq_transition_begin(policy, &freqs); 1898 cpufreq_freq_transition_end(policy, &freqs, 0); 1899 } 1900 } 1901 1902 return retval; 1903 } 1904 1905 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1906 unsigned int target_freq, 1907 unsigned int relation) 1908 { 1909 unsigned int old_target_freq = target_freq; 1910 int index; 1911 1912 if (cpufreq_disabled()) 1913 return -ENODEV; 1914 1915 /* Make sure that target_freq is within supported range */ 1916 target_freq = clamp_val(target_freq, policy->min, policy->max); 1917 1918 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", 1919 policy->cpu, target_freq, relation, old_target_freq); 1920 1921 /* 1922 * This might look like a redundant call as we are checking it again 1923 * after finding index. But it is left intentionally for cases where 1924 * exactly same freq is called again and so we can save on few function 1925 * calls. 1926 */ 1927 if (target_freq == policy->cur) 1928 return 0; 1929 1930 /* Save last value to restore later on errors */ 1931 policy->restore_freq = policy->cur; 1932 1933 if (cpufreq_driver->target) 1934 return cpufreq_driver->target(policy, target_freq, relation); 1935 1936 if (!cpufreq_driver->target_index) 1937 return -EINVAL; 1938 1939 index = cpufreq_frequency_table_target(policy, target_freq, relation); 1940 1941 return __target_index(policy, index); 1942 } 1943 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1944 1945 int cpufreq_driver_target(struct cpufreq_policy *policy, 1946 unsigned int target_freq, 1947 unsigned int relation) 1948 { 1949 int ret = -EINVAL; 1950 1951 down_write(&policy->rwsem); 1952 1953 ret = __cpufreq_driver_target(policy, target_freq, relation); 1954 1955 up_write(&policy->rwsem); 1956 1957 return ret; 1958 } 1959 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1960 1961 __weak struct cpufreq_governor *cpufreq_fallback_governor(void) 1962 { 1963 return NULL; 1964 } 1965 1966 static int cpufreq_init_governor(struct cpufreq_policy *policy) 1967 { 1968 int ret; 1969 1970 /* Don't start any governor operations if we are entering suspend */ 1971 if (cpufreq_suspended) 1972 return 0; 1973 /* 1974 * Governor might not be initiated here if ACPI _PPC changed 1975 * notification happened, so check it. 1976 */ 1977 if (!policy->governor) 1978 return -EINVAL; 1979 1980 if (policy->governor->max_transition_latency && 1981 policy->cpuinfo.transition_latency > 1982 policy->governor->max_transition_latency) { 1983 struct cpufreq_governor *gov = cpufreq_fallback_governor(); 1984 1985 if (gov) { 1986 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", 1987 policy->governor->name, gov->name); 1988 policy->governor = gov; 1989 } else { 1990 return -EINVAL; 1991 } 1992 } 1993 1994 if (!try_module_get(policy->governor->owner)) 1995 return -EINVAL; 1996 1997 pr_debug("%s: for CPU %u\n", __func__, policy->cpu); 1998 1999 if (policy->governor->init) { 2000 ret = policy->governor->init(policy); 2001 if (ret) { 2002 module_put(policy->governor->owner); 2003 return ret; 2004 } 2005 } 2006 2007 return 0; 2008 } 2009 2010 static void cpufreq_exit_governor(struct cpufreq_policy *policy) 2011 { 2012 if (cpufreq_suspended || !policy->governor) 2013 return; 2014 2015 pr_debug("%s: for CPU %u\n", __func__, policy->cpu); 2016 2017 if (policy->governor->exit) 2018 policy->governor->exit(policy); 2019 2020 module_put(policy->governor->owner); 2021 } 2022 2023 static int cpufreq_start_governor(struct cpufreq_policy *policy) 2024 { 2025 int ret; 2026 2027 if (cpufreq_suspended) 2028 return 0; 2029 2030 if (!policy->governor) 2031 return -EINVAL; 2032 2033 pr_debug("%s: for CPU %u\n", __func__, policy->cpu); 2034 2035 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) 2036 cpufreq_update_current_freq(policy); 2037 2038 if (policy->governor->start) { 2039 ret = policy->governor->start(policy); 2040 if (ret) 2041 return ret; 2042 } 2043 2044 if (policy->governor->limits) 2045 policy->governor->limits(policy); 2046 2047 return 0; 2048 } 2049 2050 static void cpufreq_stop_governor(struct cpufreq_policy *policy) 2051 { 2052 if (cpufreq_suspended || !policy->governor) 2053 return; 2054 2055 pr_debug("%s: for CPU %u\n", __func__, policy->cpu); 2056 2057 if (policy->governor->stop) 2058 policy->governor->stop(policy); 2059 } 2060 2061 static void cpufreq_governor_limits(struct cpufreq_policy *policy) 2062 { 2063 if (cpufreq_suspended || !policy->governor) 2064 return; 2065 2066 pr_debug("%s: for CPU %u\n", __func__, policy->cpu); 2067 2068 if (policy->governor->limits) 2069 policy->governor->limits(policy); 2070 } 2071 2072 int cpufreq_register_governor(struct cpufreq_governor *governor) 2073 { 2074 int err; 2075 2076 if (!governor) 2077 return -EINVAL; 2078 2079 if (cpufreq_disabled()) 2080 return -ENODEV; 2081 2082 mutex_lock(&cpufreq_governor_mutex); 2083 2084 err = -EBUSY; 2085 if (!find_governor(governor->name)) { 2086 err = 0; 2087 list_add(&governor->governor_list, &cpufreq_governor_list); 2088 } 2089 2090 mutex_unlock(&cpufreq_governor_mutex); 2091 return err; 2092 } 2093 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 2094 2095 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 2096 { 2097 struct cpufreq_policy *policy; 2098 unsigned long flags; 2099 2100 if (!governor) 2101 return; 2102 2103 if (cpufreq_disabled()) 2104 return; 2105 2106 /* clear last_governor for all inactive policies */ 2107 read_lock_irqsave(&cpufreq_driver_lock, flags); 2108 for_each_inactive_policy(policy) { 2109 if (!strcmp(policy->last_governor, governor->name)) { 2110 policy->governor = NULL; 2111 strcpy(policy->last_governor, "\0"); 2112 } 2113 } 2114 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 2115 2116 mutex_lock(&cpufreq_governor_mutex); 2117 list_del(&governor->governor_list); 2118 mutex_unlock(&cpufreq_governor_mutex); 2119 return; 2120 } 2121 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 2122 2123 2124 /********************************************************************* 2125 * POLICY INTERFACE * 2126 *********************************************************************/ 2127 2128 /** 2129 * cpufreq_get_policy - get the current cpufreq_policy 2130 * @policy: struct cpufreq_policy into which the current cpufreq_policy 2131 * is written 2132 * 2133 * Reads the current cpufreq policy. 2134 */ 2135 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 2136 { 2137 struct cpufreq_policy *cpu_policy; 2138 if (!policy) 2139 return -EINVAL; 2140 2141 cpu_policy = cpufreq_cpu_get(cpu); 2142 if (!cpu_policy) 2143 return -EINVAL; 2144 2145 memcpy(policy, cpu_policy, sizeof(*policy)); 2146 2147 cpufreq_cpu_put(cpu_policy); 2148 return 0; 2149 } 2150 EXPORT_SYMBOL(cpufreq_get_policy); 2151 2152 /* 2153 * policy : current policy. 2154 * new_policy: policy to be set. 2155 */ 2156 static int cpufreq_set_policy(struct cpufreq_policy *policy, 2157 struct cpufreq_policy *new_policy) 2158 { 2159 struct cpufreq_governor *old_gov; 2160 int ret; 2161 2162 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", 2163 new_policy->cpu, new_policy->min, new_policy->max); 2164 2165 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); 2166 2167 /* 2168 * This check works well when we store new min/max freq attributes, 2169 * because new_policy is a copy of policy with one field updated. 2170 */ 2171 if (new_policy->min > new_policy->max) 2172 return -EINVAL; 2173 2174 /* verify the cpu speed can be set within this limit */ 2175 ret = cpufreq_driver->verify(new_policy); 2176 if (ret) 2177 return ret; 2178 2179 /* adjust if necessary - all reasons */ 2180 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2181 CPUFREQ_ADJUST, new_policy); 2182 2183 /* 2184 * verify the cpu speed can be set within this limit, which might be 2185 * different to the first one 2186 */ 2187 ret = cpufreq_driver->verify(new_policy); 2188 if (ret) 2189 return ret; 2190 2191 /* notification of the new policy */ 2192 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2193 CPUFREQ_NOTIFY, new_policy); 2194 2195 policy->min = new_policy->min; 2196 policy->max = new_policy->max; 2197 2198 policy->cached_target_freq = UINT_MAX; 2199 2200 pr_debug("new min and max freqs are %u - %u kHz\n", 2201 policy->min, policy->max); 2202 2203 if (cpufreq_driver->setpolicy) { 2204 policy->policy = new_policy->policy; 2205 pr_debug("setting range\n"); 2206 return cpufreq_driver->setpolicy(new_policy); 2207 } 2208 2209 if (new_policy->governor == policy->governor) { 2210 pr_debug("cpufreq: governor limits update\n"); 2211 cpufreq_governor_limits(policy); 2212 return 0; 2213 } 2214 2215 pr_debug("governor switch\n"); 2216 2217 /* save old, working values */ 2218 old_gov = policy->governor; 2219 /* end old governor */ 2220 if (old_gov) { 2221 cpufreq_stop_governor(policy); 2222 cpufreq_exit_governor(policy); 2223 } 2224 2225 /* start new governor */ 2226 policy->governor = new_policy->governor; 2227 ret = cpufreq_init_governor(policy); 2228 if (!ret) { 2229 ret = cpufreq_start_governor(policy); 2230 if (!ret) { 2231 pr_debug("cpufreq: governor change\n"); 2232 return 0; 2233 } 2234 cpufreq_exit_governor(policy); 2235 } 2236 2237 /* new governor failed, so re-start old one */ 2238 pr_debug("starting governor %s failed\n", policy->governor->name); 2239 if (old_gov) { 2240 policy->governor = old_gov; 2241 if (cpufreq_init_governor(policy)) 2242 policy->governor = NULL; 2243 else 2244 cpufreq_start_governor(policy); 2245 } 2246 2247 return ret; 2248 } 2249 2250 /** 2251 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 2252 * @cpu: CPU which shall be re-evaluated 2253 * 2254 * Useful for policy notifiers which have different necessities 2255 * at different times. 2256 */ 2257 int cpufreq_update_policy(unsigned int cpu) 2258 { 2259 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 2260 struct cpufreq_policy new_policy; 2261 int ret; 2262 2263 if (!policy) 2264 return -ENODEV; 2265 2266 down_write(&policy->rwsem); 2267 2268 pr_debug("updating policy for CPU %u\n", cpu); 2269 memcpy(&new_policy, policy, sizeof(*policy)); 2270 new_policy.min = policy->user_policy.min; 2271 new_policy.max = policy->user_policy.max; 2272 2273 /* 2274 * BIOS might change freq behind our back 2275 * -> ask driver for current freq and notify governors about a change 2276 */ 2277 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 2278 if (cpufreq_suspended) { 2279 ret = -EAGAIN; 2280 goto unlock; 2281 } 2282 new_policy.cur = cpufreq_update_current_freq(policy); 2283 if (WARN_ON(!new_policy.cur)) { 2284 ret = -EIO; 2285 goto unlock; 2286 } 2287 } 2288 2289 ret = cpufreq_set_policy(policy, &new_policy); 2290 2291 unlock: 2292 up_write(&policy->rwsem); 2293 2294 cpufreq_cpu_put(policy); 2295 return ret; 2296 } 2297 EXPORT_SYMBOL(cpufreq_update_policy); 2298 2299 /********************************************************************* 2300 * BOOST * 2301 *********************************************************************/ 2302 static int cpufreq_boost_set_sw(int state) 2303 { 2304 struct cpufreq_policy *policy; 2305 int ret = -EINVAL; 2306 2307 for_each_active_policy(policy) { 2308 if (!policy->freq_table) 2309 continue; 2310 2311 ret = cpufreq_frequency_table_cpuinfo(policy, 2312 policy->freq_table); 2313 if (ret) { 2314 pr_err("%s: Policy frequency update failed\n", 2315 __func__); 2316 break; 2317 } 2318 2319 down_write(&policy->rwsem); 2320 policy->user_policy.max = policy->max; 2321 cpufreq_governor_limits(policy); 2322 up_write(&policy->rwsem); 2323 } 2324 2325 return ret; 2326 } 2327 2328 int cpufreq_boost_trigger_state(int state) 2329 { 2330 unsigned long flags; 2331 int ret = 0; 2332 2333 if (cpufreq_driver->boost_enabled == state) 2334 return 0; 2335 2336 write_lock_irqsave(&cpufreq_driver_lock, flags); 2337 cpufreq_driver->boost_enabled = state; 2338 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2339 2340 ret = cpufreq_driver->set_boost(state); 2341 if (ret) { 2342 write_lock_irqsave(&cpufreq_driver_lock, flags); 2343 cpufreq_driver->boost_enabled = !state; 2344 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2345 2346 pr_err("%s: Cannot %s BOOST\n", 2347 __func__, state ? "enable" : "disable"); 2348 } 2349 2350 return ret; 2351 } 2352 2353 static bool cpufreq_boost_supported(void) 2354 { 2355 return likely(cpufreq_driver) && cpufreq_driver->set_boost; 2356 } 2357 2358 static int create_boost_sysfs_file(void) 2359 { 2360 int ret; 2361 2362 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr); 2363 if (ret) 2364 pr_err("%s: cannot register global BOOST sysfs file\n", 2365 __func__); 2366 2367 return ret; 2368 } 2369 2370 static void remove_boost_sysfs_file(void) 2371 { 2372 if (cpufreq_boost_supported()) 2373 sysfs_remove_file(cpufreq_global_kobject, &boost.attr); 2374 } 2375 2376 int cpufreq_enable_boost_support(void) 2377 { 2378 if (!cpufreq_driver) 2379 return -EINVAL; 2380 2381 if (cpufreq_boost_supported()) 2382 return 0; 2383 2384 cpufreq_driver->set_boost = cpufreq_boost_set_sw; 2385 2386 /* This will get removed on driver unregister */ 2387 return create_boost_sysfs_file(); 2388 } 2389 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support); 2390 2391 int cpufreq_boost_enabled(void) 2392 { 2393 return cpufreq_driver->boost_enabled; 2394 } 2395 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); 2396 2397 /********************************************************************* 2398 * REGISTER / UNREGISTER CPUFREQ DRIVER * 2399 *********************************************************************/ 2400 static enum cpuhp_state hp_online; 2401 2402 /** 2403 * cpufreq_register_driver - register a CPU Frequency driver 2404 * @driver_data: A struct cpufreq_driver containing the values# 2405 * submitted by the CPU Frequency driver. 2406 * 2407 * Registers a CPU Frequency driver to this core code. This code 2408 * returns zero on success, -EEXIST when another driver got here first 2409 * (and isn't unregistered in the meantime). 2410 * 2411 */ 2412 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 2413 { 2414 unsigned long flags; 2415 int ret; 2416 2417 if (cpufreq_disabled()) 2418 return -ENODEV; 2419 2420 if (!driver_data || !driver_data->verify || !driver_data->init || 2421 !(driver_data->setpolicy || driver_data->target_index || 2422 driver_data->target) || 2423 (driver_data->setpolicy && (driver_data->target_index || 2424 driver_data->target)) || 2425 (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) 2426 return -EINVAL; 2427 2428 pr_debug("trying to register driver %s\n", driver_data->name); 2429 2430 /* Protect against concurrent CPU online/offline. */ 2431 get_online_cpus(); 2432 2433 write_lock_irqsave(&cpufreq_driver_lock, flags); 2434 if (cpufreq_driver) { 2435 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2436 ret = -EEXIST; 2437 goto out; 2438 } 2439 cpufreq_driver = driver_data; 2440 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2441 2442 if (driver_data->setpolicy) 2443 driver_data->flags |= CPUFREQ_CONST_LOOPS; 2444 2445 if (cpufreq_boost_supported()) { 2446 ret = create_boost_sysfs_file(); 2447 if (ret) 2448 goto err_null_driver; 2449 } 2450 2451 ret = subsys_interface_register(&cpufreq_interface); 2452 if (ret) 2453 goto err_boost_unreg; 2454 2455 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) && 2456 list_empty(&cpufreq_policy_list)) { 2457 /* if all ->init() calls failed, unregister */ 2458 pr_debug("%s: No CPU initialized for driver %s\n", __func__, 2459 driver_data->name); 2460 goto err_if_unreg; 2461 } 2462 2463 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", 2464 cpufreq_online, 2465 cpufreq_offline); 2466 if (ret < 0) 2467 goto err_if_unreg; 2468 hp_online = ret; 2469 ret = 0; 2470 2471 pr_debug("driver %s up and running\n", driver_data->name); 2472 goto out; 2473 2474 err_if_unreg: 2475 subsys_interface_unregister(&cpufreq_interface); 2476 err_boost_unreg: 2477 remove_boost_sysfs_file(); 2478 err_null_driver: 2479 write_lock_irqsave(&cpufreq_driver_lock, flags); 2480 cpufreq_driver = NULL; 2481 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2482 out: 2483 put_online_cpus(); 2484 return ret; 2485 } 2486 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 2487 2488 /** 2489 * cpufreq_unregister_driver - unregister the current CPUFreq driver 2490 * 2491 * Unregister the current CPUFreq driver. Only call this if you have 2492 * the right to do so, i.e. if you have succeeded in initialising before! 2493 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 2494 * currently not initialised. 2495 */ 2496 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 2497 { 2498 unsigned long flags; 2499 2500 if (!cpufreq_driver || (driver != cpufreq_driver)) 2501 return -EINVAL; 2502 2503 pr_debug("unregistering driver %s\n", driver->name); 2504 2505 /* Protect against concurrent cpu hotplug */ 2506 get_online_cpus(); 2507 subsys_interface_unregister(&cpufreq_interface); 2508 remove_boost_sysfs_file(); 2509 cpuhp_remove_state_nocalls(hp_online); 2510 2511 write_lock_irqsave(&cpufreq_driver_lock, flags); 2512 2513 cpufreq_driver = NULL; 2514 2515 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2516 put_online_cpus(); 2517 2518 return 0; 2519 } 2520 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 2521 2522 /* 2523 * Stop cpufreq at shutdown to make sure it isn't holding any locks 2524 * or mutexes when secondary CPUs are halted. 2525 */ 2526 static struct syscore_ops cpufreq_syscore_ops = { 2527 .shutdown = cpufreq_suspend, 2528 }; 2529 2530 struct kobject *cpufreq_global_kobject; 2531 EXPORT_SYMBOL(cpufreq_global_kobject); 2532 2533 static int __init cpufreq_core_init(void) 2534 { 2535 if (cpufreq_disabled()) 2536 return -ENODEV; 2537 2538 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj); 2539 BUG_ON(!cpufreq_global_kobject); 2540 2541 register_syscore_ops(&cpufreq_syscore_ops); 2542 2543 return 0; 2544 } 2545 core_initcall(cpufreq_core_init); 2546