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