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/tick.h> 31 #include <trace/events/power.h> 32 33 /** 34 * The "cpufreq driver" - the arch- or hardware-dependent low 35 * level driver of CPUFreq support, and its spinlock. This lock 36 * also protects the cpufreq_cpu_data array. 37 */ 38 static struct cpufreq_driver *cpufreq_driver; 39 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); 40 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback); 41 static DEFINE_RWLOCK(cpufreq_driver_lock); 42 DEFINE_MUTEX(cpufreq_governor_lock); 43 static LIST_HEAD(cpufreq_policy_list); 44 45 /* This one keeps track of the previously set governor of a removed CPU */ 46 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); 47 48 /* Flag to suspend/resume CPUFreq governors */ 49 static bool cpufreq_suspended; 50 51 static inline bool has_target(void) 52 { 53 return cpufreq_driver->target_index || cpufreq_driver->target; 54 } 55 56 /* 57 * rwsem to guarantee that cpufreq driver module doesn't unload during critical 58 * sections 59 */ 60 static DECLARE_RWSEM(cpufreq_rwsem); 61 62 /* internal prototypes */ 63 static int __cpufreq_governor(struct cpufreq_policy *policy, 64 unsigned int event); 65 static unsigned int __cpufreq_get(unsigned int cpu); 66 static void handle_update(struct work_struct *work); 67 68 /** 69 * Two notifier lists: the "policy" list is involved in the 70 * validation process for a new CPU frequency policy; the 71 * "transition" list for kernel code that needs to handle 72 * changes to devices when the CPU clock speed changes. 73 * The mutex locks both lists. 74 */ 75 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); 76 static struct srcu_notifier_head cpufreq_transition_notifier_list; 77 78 static bool init_cpufreq_transition_notifier_list_called; 79 static int __init init_cpufreq_transition_notifier_list(void) 80 { 81 srcu_init_notifier_head(&cpufreq_transition_notifier_list); 82 init_cpufreq_transition_notifier_list_called = true; 83 return 0; 84 } 85 pure_initcall(init_cpufreq_transition_notifier_list); 86 87 static int off __read_mostly; 88 static int cpufreq_disabled(void) 89 { 90 return off; 91 } 92 void disable_cpufreq(void) 93 { 94 off = 1; 95 } 96 static LIST_HEAD(cpufreq_governor_list); 97 static DEFINE_MUTEX(cpufreq_governor_mutex); 98 99 bool have_governor_per_policy(void) 100 { 101 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY); 102 } 103 EXPORT_SYMBOL_GPL(have_governor_per_policy); 104 105 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) 106 { 107 if (have_governor_per_policy()) 108 return &policy->kobj; 109 else 110 return cpufreq_global_kobject; 111 } 112 EXPORT_SYMBOL_GPL(get_governor_parent_kobj); 113 114 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) 115 { 116 u64 idle_time; 117 u64 cur_wall_time; 118 u64 busy_time; 119 120 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); 121 122 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; 123 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; 124 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; 125 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; 126 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; 127 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 128 129 idle_time = cur_wall_time - busy_time; 130 if (wall) 131 *wall = cputime_to_usecs(cur_wall_time); 132 133 return cputime_to_usecs(idle_time); 134 } 135 136 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) 137 { 138 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); 139 140 if (idle_time == -1ULL) 141 return get_cpu_idle_time_jiffy(cpu, wall); 142 else if (!io_busy) 143 idle_time += get_cpu_iowait_time_us(cpu, wall); 144 145 return idle_time; 146 } 147 EXPORT_SYMBOL_GPL(get_cpu_idle_time); 148 149 /* 150 * This is a generic cpufreq init() routine which can be used by cpufreq 151 * drivers of SMP systems. It will do following: 152 * - validate & show freq table passed 153 * - set policies transition latency 154 * - policy->cpus with all possible CPUs 155 */ 156 int cpufreq_generic_init(struct cpufreq_policy *policy, 157 struct cpufreq_frequency_table *table, 158 unsigned int transition_latency) 159 { 160 int ret; 161 162 ret = cpufreq_table_validate_and_show(policy, table); 163 if (ret) { 164 pr_err("%s: invalid frequency table: %d\n", __func__, ret); 165 return ret; 166 } 167 168 policy->cpuinfo.transition_latency = transition_latency; 169 170 /* 171 * The driver only supports the SMP configuartion where all processors 172 * share the clock and voltage and clock. 173 */ 174 cpumask_setall(policy->cpus); 175 176 return 0; 177 } 178 EXPORT_SYMBOL_GPL(cpufreq_generic_init); 179 180 unsigned int cpufreq_generic_get(unsigned int cpu) 181 { 182 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 183 184 if (!policy || IS_ERR(policy->clk)) { 185 pr_err("%s: No %s associated to cpu: %d\n", 186 __func__, policy ? "clk" : "policy", cpu); 187 return 0; 188 } 189 190 return clk_get_rate(policy->clk) / 1000; 191 } 192 EXPORT_SYMBOL_GPL(cpufreq_generic_get); 193 194 /* Only for cpufreq core internal use */ 195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu) 196 { 197 return per_cpu(cpufreq_cpu_data, cpu); 198 } 199 200 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) 201 { 202 struct cpufreq_policy *policy = NULL; 203 unsigned long flags; 204 205 if (cpufreq_disabled() || (cpu >= nr_cpu_ids)) 206 return NULL; 207 208 if (!down_read_trylock(&cpufreq_rwsem)) 209 return NULL; 210 211 /* get the cpufreq driver */ 212 read_lock_irqsave(&cpufreq_driver_lock, flags); 213 214 if (cpufreq_driver) { 215 /* get the CPU */ 216 policy = per_cpu(cpufreq_cpu_data, cpu); 217 if (policy) 218 kobject_get(&policy->kobj); 219 } 220 221 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 222 223 if (!policy) 224 up_read(&cpufreq_rwsem); 225 226 return policy; 227 } 228 EXPORT_SYMBOL_GPL(cpufreq_cpu_get); 229 230 void cpufreq_cpu_put(struct cpufreq_policy *policy) 231 { 232 if (cpufreq_disabled()) 233 return; 234 235 kobject_put(&policy->kobj); 236 up_read(&cpufreq_rwsem); 237 } 238 EXPORT_SYMBOL_GPL(cpufreq_cpu_put); 239 240 /********************************************************************* 241 * EXTERNALLY AFFECTING FREQUENCY CHANGES * 242 *********************************************************************/ 243 244 /** 245 * adjust_jiffies - adjust the system "loops_per_jiffy" 246 * 247 * This function alters the system "loops_per_jiffy" for the clock 248 * speed change. Note that loops_per_jiffy cannot be updated on SMP 249 * systems as each CPU might be scaled differently. So, use the arch 250 * per-CPU loops_per_jiffy value wherever possible. 251 */ 252 #ifndef CONFIG_SMP 253 static unsigned long l_p_j_ref; 254 static unsigned int l_p_j_ref_freq; 255 256 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 257 { 258 if (ci->flags & CPUFREQ_CONST_LOOPS) 259 return; 260 261 if (!l_p_j_ref_freq) { 262 l_p_j_ref = loops_per_jiffy; 263 l_p_j_ref_freq = ci->old; 264 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", 265 l_p_j_ref, l_p_j_ref_freq); 266 } 267 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) { 268 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, 269 ci->new); 270 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n", 271 loops_per_jiffy, ci->new); 272 } 273 } 274 #else 275 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 276 { 277 return; 278 } 279 #endif 280 281 static void __cpufreq_notify_transition(struct cpufreq_policy *policy, 282 struct cpufreq_freqs *freqs, unsigned int state) 283 { 284 BUG_ON(irqs_disabled()); 285 286 if (cpufreq_disabled()) 287 return; 288 289 freqs->flags = cpufreq_driver->flags; 290 pr_debug("notification %u of frequency transition to %u kHz\n", 291 state, freqs->new); 292 293 switch (state) { 294 295 case CPUFREQ_PRECHANGE: 296 /* detect if the driver reported a value as "old frequency" 297 * which is not equal to what the cpufreq core thinks is 298 * "old frequency". 299 */ 300 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 301 if ((policy) && (policy->cpu == freqs->cpu) && 302 (policy->cur) && (policy->cur != freqs->old)) { 303 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n", 304 freqs->old, policy->cur); 305 freqs->old = policy->cur; 306 } 307 } 308 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 309 CPUFREQ_PRECHANGE, freqs); 310 adjust_jiffies(CPUFREQ_PRECHANGE, freqs); 311 break; 312 313 case CPUFREQ_POSTCHANGE: 314 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); 315 pr_debug("FREQ: %lu - CPU: %lu\n", 316 (unsigned long)freqs->new, (unsigned long)freqs->cpu); 317 trace_cpu_frequency(freqs->new, freqs->cpu); 318 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 319 CPUFREQ_POSTCHANGE, freqs); 320 if (likely(policy) && likely(policy->cpu == freqs->cpu)) 321 policy->cur = freqs->new; 322 break; 323 } 324 } 325 326 /** 327 * cpufreq_notify_transition - call notifier chain and adjust_jiffies 328 * on frequency transition. 329 * 330 * This function calls the transition notifiers and the "adjust_jiffies" 331 * function. It is called twice on all CPU frequency changes that have 332 * external effects. 333 */ 334 static void cpufreq_notify_transition(struct cpufreq_policy *policy, 335 struct cpufreq_freqs *freqs, unsigned int state) 336 { 337 for_each_cpu(freqs->cpu, policy->cpus) 338 __cpufreq_notify_transition(policy, freqs, state); 339 } 340 341 /* Do post notifications when there are chances that transition has failed */ 342 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy, 343 struct cpufreq_freqs *freqs, int transition_failed) 344 { 345 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); 346 if (!transition_failed) 347 return; 348 349 swap(freqs->old, freqs->new); 350 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); 351 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); 352 } 353 354 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy, 355 struct cpufreq_freqs *freqs) 356 { 357 358 /* 359 * Catch double invocations of _begin() which lead to self-deadlock. 360 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core 361 * doesn't invoke _begin() on their behalf, and hence the chances of 362 * double invocations are very low. Moreover, there are scenarios 363 * where these checks can emit false-positive warnings in these 364 * drivers; so we avoid that by skipping them altogether. 365 */ 366 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION) 367 && current == policy->transition_task); 368 369 wait: 370 wait_event(policy->transition_wait, !policy->transition_ongoing); 371 372 spin_lock(&policy->transition_lock); 373 374 if (unlikely(policy->transition_ongoing)) { 375 spin_unlock(&policy->transition_lock); 376 goto wait; 377 } 378 379 policy->transition_ongoing = true; 380 policy->transition_task = current; 381 382 spin_unlock(&policy->transition_lock); 383 384 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); 385 } 386 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); 387 388 void cpufreq_freq_transition_end(struct cpufreq_policy *policy, 389 struct cpufreq_freqs *freqs, int transition_failed) 390 { 391 if (unlikely(WARN_ON(!policy->transition_ongoing))) 392 return; 393 394 cpufreq_notify_post_transition(policy, freqs, transition_failed); 395 396 policy->transition_ongoing = false; 397 policy->transition_task = NULL; 398 399 wake_up(&policy->transition_wait); 400 } 401 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end); 402 403 404 /********************************************************************* 405 * SYSFS INTERFACE * 406 *********************************************************************/ 407 static ssize_t show_boost(struct kobject *kobj, 408 struct attribute *attr, char *buf) 409 { 410 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled); 411 } 412 413 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr, 414 const char *buf, size_t count) 415 { 416 int ret, enable; 417 418 ret = sscanf(buf, "%d", &enable); 419 if (ret != 1 || enable < 0 || enable > 1) 420 return -EINVAL; 421 422 if (cpufreq_boost_trigger_state(enable)) { 423 pr_err("%s: Cannot %s BOOST!\n", 424 __func__, enable ? "enable" : "disable"); 425 return -EINVAL; 426 } 427 428 pr_debug("%s: cpufreq BOOST %s\n", 429 __func__, enable ? "enabled" : "disabled"); 430 431 return count; 432 } 433 define_one_global_rw(boost); 434 435 static struct cpufreq_governor *__find_governor(const char *str_governor) 436 { 437 struct cpufreq_governor *t; 438 439 list_for_each_entry(t, &cpufreq_governor_list, governor_list) 440 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN)) 441 return t; 442 443 return NULL; 444 } 445 446 /** 447 * cpufreq_parse_governor - parse a governor string 448 */ 449 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, 450 struct cpufreq_governor **governor) 451 { 452 int err = -EINVAL; 453 454 if (!cpufreq_driver) 455 goto out; 456 457 if (cpufreq_driver->setpolicy) { 458 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { 459 *policy = CPUFREQ_POLICY_PERFORMANCE; 460 err = 0; 461 } else if (!strnicmp(str_governor, "powersave", 462 CPUFREQ_NAME_LEN)) { 463 *policy = CPUFREQ_POLICY_POWERSAVE; 464 err = 0; 465 } 466 } else if (has_target()) { 467 struct cpufreq_governor *t; 468 469 mutex_lock(&cpufreq_governor_mutex); 470 471 t = __find_governor(str_governor); 472 473 if (t == NULL) { 474 int ret; 475 476 mutex_unlock(&cpufreq_governor_mutex); 477 ret = request_module("cpufreq_%s", str_governor); 478 mutex_lock(&cpufreq_governor_mutex); 479 480 if (ret == 0) 481 t = __find_governor(str_governor); 482 } 483 484 if (t != NULL) { 485 *governor = t; 486 err = 0; 487 } 488 489 mutex_unlock(&cpufreq_governor_mutex); 490 } 491 out: 492 return err; 493 } 494 495 /** 496 * cpufreq_per_cpu_attr_read() / show_##file_name() - 497 * print out cpufreq information 498 * 499 * Write out information from cpufreq_driver->policy[cpu]; object must be 500 * "unsigned int". 501 */ 502 503 #define show_one(file_name, object) \ 504 static ssize_t show_##file_name \ 505 (struct cpufreq_policy *policy, char *buf) \ 506 { \ 507 return sprintf(buf, "%u\n", policy->object); \ 508 } 509 510 show_one(cpuinfo_min_freq, cpuinfo.min_freq); 511 show_one(cpuinfo_max_freq, cpuinfo.max_freq); 512 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); 513 show_one(scaling_min_freq, min); 514 show_one(scaling_max_freq, max); 515 show_one(scaling_cur_freq, cur); 516 517 static int cpufreq_set_policy(struct cpufreq_policy *policy, 518 struct cpufreq_policy *new_policy); 519 520 /** 521 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access 522 */ 523 #define store_one(file_name, object) \ 524 static ssize_t store_##file_name \ 525 (struct cpufreq_policy *policy, const char *buf, size_t count) \ 526 { \ 527 int ret; \ 528 struct cpufreq_policy new_policy; \ 529 \ 530 ret = cpufreq_get_policy(&new_policy, policy->cpu); \ 531 if (ret) \ 532 return -EINVAL; \ 533 \ 534 ret = sscanf(buf, "%u", &new_policy.object); \ 535 if (ret != 1) \ 536 return -EINVAL; \ 537 \ 538 ret = cpufreq_set_policy(policy, &new_policy); \ 539 policy->user_policy.object = policy->object; \ 540 \ 541 return ret ? ret : count; \ 542 } 543 544 store_one(scaling_min_freq, min); 545 store_one(scaling_max_freq, max); 546 547 /** 548 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware 549 */ 550 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, 551 char *buf) 552 { 553 unsigned int cur_freq = __cpufreq_get(policy->cpu); 554 if (!cur_freq) 555 return sprintf(buf, "<unknown>"); 556 return sprintf(buf, "%u\n", cur_freq); 557 } 558 559 /** 560 * show_scaling_governor - show the current policy for the specified CPU 561 */ 562 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) 563 { 564 if (policy->policy == CPUFREQ_POLICY_POWERSAVE) 565 return sprintf(buf, "powersave\n"); 566 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) 567 return sprintf(buf, "performance\n"); 568 else if (policy->governor) 569 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", 570 policy->governor->name); 571 return -EINVAL; 572 } 573 574 /** 575 * store_scaling_governor - store policy for the specified CPU 576 */ 577 static ssize_t store_scaling_governor(struct cpufreq_policy *policy, 578 const char *buf, size_t count) 579 { 580 int ret; 581 char str_governor[16]; 582 struct cpufreq_policy new_policy; 583 584 ret = cpufreq_get_policy(&new_policy, policy->cpu); 585 if (ret) 586 return ret; 587 588 ret = sscanf(buf, "%15s", str_governor); 589 if (ret != 1) 590 return -EINVAL; 591 592 if (cpufreq_parse_governor(str_governor, &new_policy.policy, 593 &new_policy.governor)) 594 return -EINVAL; 595 596 ret = cpufreq_set_policy(policy, &new_policy); 597 598 policy->user_policy.policy = policy->policy; 599 policy->user_policy.governor = policy->governor; 600 601 if (ret) 602 return ret; 603 else 604 return count; 605 } 606 607 /** 608 * show_scaling_driver - show the cpufreq driver currently loaded 609 */ 610 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) 611 { 612 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); 613 } 614 615 /** 616 * show_scaling_available_governors - show the available CPUfreq governors 617 */ 618 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, 619 char *buf) 620 { 621 ssize_t i = 0; 622 struct cpufreq_governor *t; 623 624 if (!has_target()) { 625 i += sprintf(buf, "performance powersave"); 626 goto out; 627 } 628 629 list_for_each_entry(t, &cpufreq_governor_list, governor_list) { 630 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) 631 - (CPUFREQ_NAME_LEN + 2))) 632 goto out; 633 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); 634 } 635 out: 636 i += sprintf(&buf[i], "\n"); 637 return i; 638 } 639 640 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) 641 { 642 ssize_t i = 0; 643 unsigned int cpu; 644 645 for_each_cpu(cpu, mask) { 646 if (i) 647 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); 648 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); 649 if (i >= (PAGE_SIZE - 5)) 650 break; 651 } 652 i += sprintf(&buf[i], "\n"); 653 return i; 654 } 655 EXPORT_SYMBOL_GPL(cpufreq_show_cpus); 656 657 /** 658 * show_related_cpus - show the CPUs affected by each transition even if 659 * hw coordination is in use 660 */ 661 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) 662 { 663 return cpufreq_show_cpus(policy->related_cpus, buf); 664 } 665 666 /** 667 * show_affected_cpus - show the CPUs affected by each transition 668 */ 669 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) 670 { 671 return cpufreq_show_cpus(policy->cpus, buf); 672 } 673 674 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, 675 const char *buf, size_t count) 676 { 677 unsigned int freq = 0; 678 unsigned int ret; 679 680 if (!policy->governor || !policy->governor->store_setspeed) 681 return -EINVAL; 682 683 ret = sscanf(buf, "%u", &freq); 684 if (ret != 1) 685 return -EINVAL; 686 687 policy->governor->store_setspeed(policy, freq); 688 689 return count; 690 } 691 692 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) 693 { 694 if (!policy->governor || !policy->governor->show_setspeed) 695 return sprintf(buf, "<unsupported>\n"); 696 697 return policy->governor->show_setspeed(policy, buf); 698 } 699 700 /** 701 * show_bios_limit - show the current cpufreq HW/BIOS limitation 702 */ 703 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) 704 { 705 unsigned int limit; 706 int ret; 707 if (cpufreq_driver->bios_limit) { 708 ret = cpufreq_driver->bios_limit(policy->cpu, &limit); 709 if (!ret) 710 return sprintf(buf, "%u\n", limit); 711 } 712 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); 713 } 714 715 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); 716 cpufreq_freq_attr_ro(cpuinfo_min_freq); 717 cpufreq_freq_attr_ro(cpuinfo_max_freq); 718 cpufreq_freq_attr_ro(cpuinfo_transition_latency); 719 cpufreq_freq_attr_ro(scaling_available_governors); 720 cpufreq_freq_attr_ro(scaling_driver); 721 cpufreq_freq_attr_ro(scaling_cur_freq); 722 cpufreq_freq_attr_ro(bios_limit); 723 cpufreq_freq_attr_ro(related_cpus); 724 cpufreq_freq_attr_ro(affected_cpus); 725 cpufreq_freq_attr_rw(scaling_min_freq); 726 cpufreq_freq_attr_rw(scaling_max_freq); 727 cpufreq_freq_attr_rw(scaling_governor); 728 cpufreq_freq_attr_rw(scaling_setspeed); 729 730 static struct attribute *default_attrs[] = { 731 &cpuinfo_min_freq.attr, 732 &cpuinfo_max_freq.attr, 733 &cpuinfo_transition_latency.attr, 734 &scaling_min_freq.attr, 735 &scaling_max_freq.attr, 736 &affected_cpus.attr, 737 &related_cpus.attr, 738 &scaling_governor.attr, 739 &scaling_driver.attr, 740 &scaling_available_governors.attr, 741 &scaling_setspeed.attr, 742 NULL 743 }; 744 745 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) 746 #define to_attr(a) container_of(a, struct freq_attr, attr) 747 748 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) 749 { 750 struct cpufreq_policy *policy = to_policy(kobj); 751 struct freq_attr *fattr = to_attr(attr); 752 ssize_t ret; 753 754 if (!down_read_trylock(&cpufreq_rwsem)) 755 return -EINVAL; 756 757 down_read(&policy->rwsem); 758 759 if (fattr->show) 760 ret = fattr->show(policy, buf); 761 else 762 ret = -EIO; 763 764 up_read(&policy->rwsem); 765 up_read(&cpufreq_rwsem); 766 767 return ret; 768 } 769 770 static ssize_t store(struct kobject *kobj, struct attribute *attr, 771 const char *buf, size_t count) 772 { 773 struct cpufreq_policy *policy = to_policy(kobj); 774 struct freq_attr *fattr = to_attr(attr); 775 ssize_t ret = -EINVAL; 776 777 get_online_cpus(); 778 779 if (!cpu_online(policy->cpu)) 780 goto unlock; 781 782 if (!down_read_trylock(&cpufreq_rwsem)) 783 goto unlock; 784 785 down_write(&policy->rwsem); 786 787 if (fattr->store) 788 ret = fattr->store(policy, buf, count); 789 else 790 ret = -EIO; 791 792 up_write(&policy->rwsem); 793 794 up_read(&cpufreq_rwsem); 795 unlock: 796 put_online_cpus(); 797 798 return ret; 799 } 800 801 static void cpufreq_sysfs_release(struct kobject *kobj) 802 { 803 struct cpufreq_policy *policy = to_policy(kobj); 804 pr_debug("last reference is dropped\n"); 805 complete(&policy->kobj_unregister); 806 } 807 808 static const struct sysfs_ops sysfs_ops = { 809 .show = show, 810 .store = store, 811 }; 812 813 static struct kobj_type ktype_cpufreq = { 814 .sysfs_ops = &sysfs_ops, 815 .default_attrs = default_attrs, 816 .release = cpufreq_sysfs_release, 817 }; 818 819 struct kobject *cpufreq_global_kobject; 820 EXPORT_SYMBOL(cpufreq_global_kobject); 821 822 static int cpufreq_global_kobject_usage; 823 824 int cpufreq_get_global_kobject(void) 825 { 826 if (!cpufreq_global_kobject_usage++) 827 return kobject_add(cpufreq_global_kobject, 828 &cpu_subsys.dev_root->kobj, "%s", "cpufreq"); 829 830 return 0; 831 } 832 EXPORT_SYMBOL(cpufreq_get_global_kobject); 833 834 void cpufreq_put_global_kobject(void) 835 { 836 if (!--cpufreq_global_kobject_usage) 837 kobject_del(cpufreq_global_kobject); 838 } 839 EXPORT_SYMBOL(cpufreq_put_global_kobject); 840 841 int cpufreq_sysfs_create_file(const struct attribute *attr) 842 { 843 int ret = cpufreq_get_global_kobject(); 844 845 if (!ret) { 846 ret = sysfs_create_file(cpufreq_global_kobject, attr); 847 if (ret) 848 cpufreq_put_global_kobject(); 849 } 850 851 return ret; 852 } 853 EXPORT_SYMBOL(cpufreq_sysfs_create_file); 854 855 void cpufreq_sysfs_remove_file(const struct attribute *attr) 856 { 857 sysfs_remove_file(cpufreq_global_kobject, attr); 858 cpufreq_put_global_kobject(); 859 } 860 EXPORT_SYMBOL(cpufreq_sysfs_remove_file); 861 862 /* symlink affected CPUs */ 863 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) 864 { 865 unsigned int j; 866 int ret = 0; 867 868 for_each_cpu(j, policy->cpus) { 869 struct device *cpu_dev; 870 871 if (j == policy->cpu) 872 continue; 873 874 pr_debug("Adding link for CPU: %u\n", j); 875 cpu_dev = get_cpu_device(j); 876 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, 877 "cpufreq"); 878 if (ret) 879 break; 880 } 881 return ret; 882 } 883 884 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, 885 struct device *dev) 886 { 887 struct freq_attr **drv_attr; 888 int ret = 0; 889 890 /* prepare interface data */ 891 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, 892 &dev->kobj, "cpufreq"); 893 if (ret) 894 return ret; 895 896 /* set up files for this cpu device */ 897 drv_attr = cpufreq_driver->attr; 898 while ((drv_attr) && (*drv_attr)) { 899 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); 900 if (ret) 901 goto err_out_kobj_put; 902 drv_attr++; 903 } 904 if (cpufreq_driver->get) { 905 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); 906 if (ret) 907 goto err_out_kobj_put; 908 } 909 if (has_target()) { 910 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); 911 if (ret) 912 goto err_out_kobj_put; 913 } 914 if (cpufreq_driver->bios_limit) { 915 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); 916 if (ret) 917 goto err_out_kobj_put; 918 } 919 920 ret = cpufreq_add_dev_symlink(policy); 921 if (ret) 922 goto err_out_kobj_put; 923 924 return ret; 925 926 err_out_kobj_put: 927 kobject_put(&policy->kobj); 928 wait_for_completion(&policy->kobj_unregister); 929 return ret; 930 } 931 932 static void cpufreq_init_policy(struct cpufreq_policy *policy) 933 { 934 struct cpufreq_governor *gov = NULL; 935 struct cpufreq_policy new_policy; 936 int ret = 0; 937 938 memcpy(&new_policy, policy, sizeof(*policy)); 939 940 /* Update governor of new_policy to the governor used before hotplug */ 941 gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu)); 942 if (gov) 943 pr_debug("Restoring governor %s for cpu %d\n", 944 policy->governor->name, policy->cpu); 945 else 946 gov = CPUFREQ_DEFAULT_GOVERNOR; 947 948 new_policy.governor = gov; 949 950 /* Use the default policy if its valid. */ 951 if (cpufreq_driver->setpolicy) 952 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL); 953 954 /* set default policy */ 955 ret = cpufreq_set_policy(policy, &new_policy); 956 if (ret) { 957 pr_debug("setting policy failed\n"); 958 if (cpufreq_driver->exit) 959 cpufreq_driver->exit(policy); 960 } 961 } 962 963 #ifdef CONFIG_HOTPLUG_CPU 964 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, 965 unsigned int cpu, struct device *dev) 966 { 967 int ret = 0; 968 unsigned long flags; 969 970 if (has_target()) { 971 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 972 if (ret) { 973 pr_err("%s: Failed to stop governor\n", __func__); 974 return ret; 975 } 976 } 977 978 down_write(&policy->rwsem); 979 980 write_lock_irqsave(&cpufreq_driver_lock, flags); 981 982 cpumask_set_cpu(cpu, policy->cpus); 983 per_cpu(cpufreq_cpu_data, cpu) = policy; 984 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 985 986 up_write(&policy->rwsem); 987 988 if (has_target()) { 989 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); 990 if (!ret) 991 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 992 993 if (ret) { 994 pr_err("%s: Failed to start governor\n", __func__); 995 return ret; 996 } 997 } 998 999 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); 1000 } 1001 #endif 1002 1003 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu) 1004 { 1005 struct cpufreq_policy *policy; 1006 unsigned long flags; 1007 1008 read_lock_irqsave(&cpufreq_driver_lock, flags); 1009 1010 policy = per_cpu(cpufreq_cpu_data_fallback, cpu); 1011 1012 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1013 1014 policy->governor = NULL; 1015 1016 return policy; 1017 } 1018 1019 static struct cpufreq_policy *cpufreq_policy_alloc(void) 1020 { 1021 struct cpufreq_policy *policy; 1022 1023 policy = kzalloc(sizeof(*policy), GFP_KERNEL); 1024 if (!policy) 1025 return NULL; 1026 1027 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) 1028 goto err_free_policy; 1029 1030 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) 1031 goto err_free_cpumask; 1032 1033 INIT_LIST_HEAD(&policy->policy_list); 1034 init_rwsem(&policy->rwsem); 1035 spin_lock_init(&policy->transition_lock); 1036 init_waitqueue_head(&policy->transition_wait); 1037 1038 return policy; 1039 1040 err_free_cpumask: 1041 free_cpumask_var(policy->cpus); 1042 err_free_policy: 1043 kfree(policy); 1044 1045 return NULL; 1046 } 1047 1048 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy) 1049 { 1050 struct kobject *kobj; 1051 struct completion *cmp; 1052 1053 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1054 CPUFREQ_REMOVE_POLICY, policy); 1055 1056 down_read(&policy->rwsem); 1057 kobj = &policy->kobj; 1058 cmp = &policy->kobj_unregister; 1059 up_read(&policy->rwsem); 1060 kobject_put(kobj); 1061 1062 /* 1063 * We need to make sure that the underlying kobj is 1064 * actually not referenced anymore by anybody before we 1065 * proceed with unloading. 1066 */ 1067 pr_debug("waiting for dropping of refcount\n"); 1068 wait_for_completion(cmp); 1069 pr_debug("wait complete\n"); 1070 } 1071 1072 static void cpufreq_policy_free(struct cpufreq_policy *policy) 1073 { 1074 free_cpumask_var(policy->related_cpus); 1075 free_cpumask_var(policy->cpus); 1076 kfree(policy); 1077 } 1078 1079 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) 1080 { 1081 if (WARN_ON(cpu == policy->cpu)) 1082 return; 1083 1084 down_write(&policy->rwsem); 1085 1086 policy->last_cpu = policy->cpu; 1087 policy->cpu = cpu; 1088 1089 up_write(&policy->rwsem); 1090 1091 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1092 CPUFREQ_UPDATE_POLICY_CPU, policy); 1093 } 1094 1095 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1096 { 1097 unsigned int j, cpu = dev->id; 1098 int ret = -ENOMEM; 1099 struct cpufreq_policy *policy; 1100 unsigned long flags; 1101 bool recover_policy = cpufreq_suspended; 1102 #ifdef CONFIG_HOTPLUG_CPU 1103 struct cpufreq_policy *tpolicy; 1104 #endif 1105 1106 if (cpu_is_offline(cpu)) 1107 return 0; 1108 1109 pr_debug("adding CPU %u\n", cpu); 1110 1111 #ifdef CONFIG_SMP 1112 /* check whether a different CPU already registered this 1113 * CPU because it is in the same boat. */ 1114 policy = cpufreq_cpu_get(cpu); 1115 if (unlikely(policy)) { 1116 cpufreq_cpu_put(policy); 1117 return 0; 1118 } 1119 #endif 1120 1121 if (!down_read_trylock(&cpufreq_rwsem)) 1122 return 0; 1123 1124 #ifdef CONFIG_HOTPLUG_CPU 1125 /* Check if this cpu was hot-unplugged earlier and has siblings */ 1126 read_lock_irqsave(&cpufreq_driver_lock, flags); 1127 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { 1128 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { 1129 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1130 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev); 1131 up_read(&cpufreq_rwsem); 1132 return ret; 1133 } 1134 } 1135 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1136 #endif 1137 1138 /* 1139 * Restore the saved policy when doing light-weight init and fall back 1140 * to the full init if that fails. 1141 */ 1142 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL; 1143 if (!policy) { 1144 recover_policy = false; 1145 policy = cpufreq_policy_alloc(); 1146 if (!policy) 1147 goto nomem_out; 1148 } 1149 1150 /* 1151 * In the resume path, since we restore a saved policy, the assignment 1152 * to policy->cpu is like an update of the existing policy, rather than 1153 * the creation of a brand new one. So we need to perform this update 1154 * by invoking update_policy_cpu(). 1155 */ 1156 if (recover_policy && cpu != policy->cpu) 1157 update_policy_cpu(policy, cpu); 1158 else 1159 policy->cpu = cpu; 1160 1161 cpumask_copy(policy->cpus, cpumask_of(cpu)); 1162 1163 init_completion(&policy->kobj_unregister); 1164 INIT_WORK(&policy->update, handle_update); 1165 1166 /* call driver. From then on the cpufreq must be able 1167 * to accept all calls to ->verify and ->setpolicy for this CPU 1168 */ 1169 ret = cpufreq_driver->init(policy); 1170 if (ret) { 1171 pr_debug("initialization failed\n"); 1172 goto err_set_policy_cpu; 1173 } 1174 1175 /* related cpus should atleast have policy->cpus */ 1176 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); 1177 1178 /* 1179 * affected cpus must always be the one, which are online. We aren't 1180 * managing offline cpus here. 1181 */ 1182 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); 1183 1184 if (!recover_policy) { 1185 policy->user_policy.min = policy->min; 1186 policy->user_policy.max = policy->max; 1187 } 1188 1189 down_write(&policy->rwsem); 1190 write_lock_irqsave(&cpufreq_driver_lock, flags); 1191 for_each_cpu(j, policy->cpus) 1192 per_cpu(cpufreq_cpu_data, j) = policy; 1193 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1194 1195 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 1196 policy->cur = cpufreq_driver->get(policy->cpu); 1197 if (!policy->cur) { 1198 pr_err("%s: ->get() failed\n", __func__); 1199 goto err_get_freq; 1200 } 1201 } 1202 1203 /* 1204 * Sometimes boot loaders set CPU frequency to a value outside of 1205 * frequency table present with cpufreq core. In such cases CPU might be 1206 * unstable if it has to run on that frequency for long duration of time 1207 * and so its better to set it to a frequency which is specified in 1208 * freq-table. This also makes cpufreq stats inconsistent as 1209 * cpufreq-stats would fail to register because current frequency of CPU 1210 * isn't found in freq-table. 1211 * 1212 * Because we don't want this change to effect boot process badly, we go 1213 * for the next freq which is >= policy->cur ('cur' must be set by now, 1214 * otherwise we will end up setting freq to lowest of the table as 'cur' 1215 * is initialized to zero). 1216 * 1217 * We are passing target-freq as "policy->cur - 1" otherwise 1218 * __cpufreq_driver_target() would simply fail, as policy->cur will be 1219 * equal to target-freq. 1220 */ 1221 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) 1222 && has_target()) { 1223 /* Are we running at unknown frequency ? */ 1224 ret = cpufreq_frequency_table_get_index(policy, policy->cur); 1225 if (ret == -EINVAL) { 1226 /* Warn user and fix it */ 1227 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", 1228 __func__, policy->cpu, policy->cur); 1229 ret = __cpufreq_driver_target(policy, policy->cur - 1, 1230 CPUFREQ_RELATION_L); 1231 1232 /* 1233 * Reaching here after boot in a few seconds may not 1234 * mean that system will remain stable at "unknown" 1235 * frequency for longer duration. Hence, a BUG_ON(). 1236 */ 1237 BUG_ON(ret); 1238 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", 1239 __func__, policy->cpu, policy->cur); 1240 } 1241 } 1242 1243 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1244 CPUFREQ_START, policy); 1245 1246 if (!recover_policy) { 1247 ret = cpufreq_add_dev_interface(policy, dev); 1248 if (ret) 1249 goto err_out_unregister; 1250 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1251 CPUFREQ_CREATE_POLICY, policy); 1252 } 1253 1254 write_lock_irqsave(&cpufreq_driver_lock, flags); 1255 list_add(&policy->policy_list, &cpufreq_policy_list); 1256 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1257 1258 cpufreq_init_policy(policy); 1259 1260 if (!recover_policy) { 1261 policy->user_policy.policy = policy->policy; 1262 policy->user_policy.governor = policy->governor; 1263 } 1264 up_write(&policy->rwsem); 1265 1266 kobject_uevent(&policy->kobj, KOBJ_ADD); 1267 up_read(&cpufreq_rwsem); 1268 1269 pr_debug("initialization complete\n"); 1270 1271 return 0; 1272 1273 err_out_unregister: 1274 err_get_freq: 1275 write_lock_irqsave(&cpufreq_driver_lock, flags); 1276 for_each_cpu(j, policy->cpus) 1277 per_cpu(cpufreq_cpu_data, j) = NULL; 1278 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1279 1280 if (cpufreq_driver->exit) 1281 cpufreq_driver->exit(policy); 1282 err_set_policy_cpu: 1283 if (recover_policy) { 1284 /* Do not leave stale fallback data behind. */ 1285 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL; 1286 cpufreq_policy_put_kobj(policy); 1287 } 1288 cpufreq_policy_free(policy); 1289 1290 nomem_out: 1291 up_read(&cpufreq_rwsem); 1292 1293 return ret; 1294 } 1295 1296 /** 1297 * cpufreq_add_dev - add a CPU device 1298 * 1299 * Adds the cpufreq interface for a CPU device. 1300 * 1301 * The Oracle says: try running cpufreq registration/unregistration concurrently 1302 * with with cpu hotplugging and all hell will break loose. Tried to clean this 1303 * mess up, but more thorough testing is needed. - Mathieu 1304 */ 1305 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1306 { 1307 return __cpufreq_add_dev(dev, sif); 1308 } 1309 1310 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, 1311 unsigned int old_cpu) 1312 { 1313 struct device *cpu_dev; 1314 int ret; 1315 1316 /* first sibling now owns the new sysfs dir */ 1317 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu)); 1318 1319 sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); 1320 ret = kobject_move(&policy->kobj, &cpu_dev->kobj); 1321 if (ret) { 1322 pr_err("%s: Failed to move kobj: %d\n", __func__, ret); 1323 1324 down_write(&policy->rwsem); 1325 cpumask_set_cpu(old_cpu, policy->cpus); 1326 up_write(&policy->rwsem); 1327 1328 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, 1329 "cpufreq"); 1330 1331 return -EINVAL; 1332 } 1333 1334 return cpu_dev->id; 1335 } 1336 1337 static int __cpufreq_remove_dev_prepare(struct device *dev, 1338 struct subsys_interface *sif) 1339 { 1340 unsigned int cpu = dev->id, cpus; 1341 int new_cpu, ret; 1342 unsigned long flags; 1343 struct cpufreq_policy *policy; 1344 1345 pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 1346 1347 write_lock_irqsave(&cpufreq_driver_lock, flags); 1348 1349 policy = per_cpu(cpufreq_cpu_data, cpu); 1350 1351 /* Save the policy somewhere when doing a light-weight tear-down */ 1352 if (cpufreq_suspended) 1353 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy; 1354 1355 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1356 1357 if (!policy) { 1358 pr_debug("%s: No cpu_data found\n", __func__); 1359 return -EINVAL; 1360 } 1361 1362 if (has_target()) { 1363 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 1364 if (ret) { 1365 pr_err("%s: Failed to stop governor\n", __func__); 1366 return ret; 1367 } 1368 } 1369 1370 if (!cpufreq_driver->setpolicy) 1371 strncpy(per_cpu(cpufreq_cpu_governor, cpu), 1372 policy->governor->name, CPUFREQ_NAME_LEN); 1373 1374 down_read(&policy->rwsem); 1375 cpus = cpumask_weight(policy->cpus); 1376 up_read(&policy->rwsem); 1377 1378 if (cpu != policy->cpu) { 1379 sysfs_remove_link(&dev->kobj, "cpufreq"); 1380 } else if (cpus > 1) { 1381 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu); 1382 if (new_cpu >= 0) { 1383 update_policy_cpu(policy, new_cpu); 1384 1385 if (!cpufreq_suspended) 1386 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", 1387 __func__, new_cpu, cpu); 1388 } 1389 } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) { 1390 cpufreq_driver->stop_cpu(policy); 1391 } 1392 1393 return 0; 1394 } 1395 1396 static int __cpufreq_remove_dev_finish(struct device *dev, 1397 struct subsys_interface *sif) 1398 { 1399 unsigned int cpu = dev->id, cpus; 1400 int ret; 1401 unsigned long flags; 1402 struct cpufreq_policy *policy; 1403 1404 read_lock_irqsave(&cpufreq_driver_lock, flags); 1405 policy = per_cpu(cpufreq_cpu_data, cpu); 1406 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1407 1408 if (!policy) { 1409 pr_debug("%s: No cpu_data found\n", __func__); 1410 return -EINVAL; 1411 } 1412 1413 down_write(&policy->rwsem); 1414 cpus = cpumask_weight(policy->cpus); 1415 1416 if (cpus > 1) 1417 cpumask_clear_cpu(cpu, policy->cpus); 1418 up_write(&policy->rwsem); 1419 1420 /* If cpu is last user of policy, free policy */ 1421 if (cpus == 1) { 1422 if (has_target()) { 1423 ret = __cpufreq_governor(policy, 1424 CPUFREQ_GOV_POLICY_EXIT); 1425 if (ret) { 1426 pr_err("%s: Failed to exit governor\n", 1427 __func__); 1428 return ret; 1429 } 1430 } 1431 1432 if (!cpufreq_suspended) 1433 cpufreq_policy_put_kobj(policy); 1434 1435 /* 1436 * Perform the ->exit() even during light-weight tear-down, 1437 * since this is a core component, and is essential for the 1438 * subsequent light-weight ->init() to succeed. 1439 */ 1440 if (cpufreq_driver->exit) 1441 cpufreq_driver->exit(policy); 1442 1443 /* Remove policy from list of active policies */ 1444 write_lock_irqsave(&cpufreq_driver_lock, flags); 1445 list_del(&policy->policy_list); 1446 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1447 1448 if (!cpufreq_suspended) 1449 cpufreq_policy_free(policy); 1450 } else if (has_target()) { 1451 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); 1452 if (!ret) 1453 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 1454 1455 if (ret) { 1456 pr_err("%s: Failed to start governor\n", __func__); 1457 return ret; 1458 } 1459 } 1460 1461 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1462 return 0; 1463 } 1464 1465 /** 1466 * cpufreq_remove_dev - remove a CPU device 1467 * 1468 * Removes the cpufreq interface for a CPU device. 1469 */ 1470 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 1471 { 1472 unsigned int cpu = dev->id; 1473 int ret; 1474 1475 if (cpu_is_offline(cpu)) 1476 return 0; 1477 1478 ret = __cpufreq_remove_dev_prepare(dev, sif); 1479 1480 if (!ret) 1481 ret = __cpufreq_remove_dev_finish(dev, sif); 1482 1483 return ret; 1484 } 1485 1486 static void handle_update(struct work_struct *work) 1487 { 1488 struct cpufreq_policy *policy = 1489 container_of(work, struct cpufreq_policy, update); 1490 unsigned int cpu = policy->cpu; 1491 pr_debug("handle_update for cpu %u called\n", cpu); 1492 cpufreq_update_policy(cpu); 1493 } 1494 1495 /** 1496 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're 1497 * in deep trouble. 1498 * @cpu: cpu number 1499 * @old_freq: CPU frequency the kernel thinks the CPU runs at 1500 * @new_freq: CPU frequency the CPU actually runs at 1501 * 1502 * We adjust to current frequency first, and need to clean up later. 1503 * So either call to cpufreq_update_policy() or schedule handle_update()). 1504 */ 1505 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, 1506 unsigned int new_freq) 1507 { 1508 struct cpufreq_policy *policy; 1509 struct cpufreq_freqs freqs; 1510 unsigned long flags; 1511 1512 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n", 1513 old_freq, new_freq); 1514 1515 freqs.old = old_freq; 1516 freqs.new = new_freq; 1517 1518 read_lock_irqsave(&cpufreq_driver_lock, flags); 1519 policy = per_cpu(cpufreq_cpu_data, cpu); 1520 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1521 1522 cpufreq_freq_transition_begin(policy, &freqs); 1523 cpufreq_freq_transition_end(policy, &freqs, 0); 1524 } 1525 1526 /** 1527 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1528 * @cpu: CPU number 1529 * 1530 * This is the last known freq, without actually getting it from the driver. 1531 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1532 */ 1533 unsigned int cpufreq_quick_get(unsigned int cpu) 1534 { 1535 struct cpufreq_policy *policy; 1536 unsigned int ret_freq = 0; 1537 1538 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) 1539 return cpufreq_driver->get(cpu); 1540 1541 policy = cpufreq_cpu_get(cpu); 1542 if (policy) { 1543 ret_freq = policy->cur; 1544 cpufreq_cpu_put(policy); 1545 } 1546 1547 return ret_freq; 1548 } 1549 EXPORT_SYMBOL(cpufreq_quick_get); 1550 1551 /** 1552 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU 1553 * @cpu: CPU number 1554 * 1555 * Just return the max possible frequency for a given CPU. 1556 */ 1557 unsigned int cpufreq_quick_get_max(unsigned int cpu) 1558 { 1559 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1560 unsigned int ret_freq = 0; 1561 1562 if (policy) { 1563 ret_freq = policy->max; 1564 cpufreq_cpu_put(policy); 1565 } 1566 1567 return ret_freq; 1568 } 1569 EXPORT_SYMBOL(cpufreq_quick_get_max); 1570 1571 static unsigned int __cpufreq_get(unsigned int cpu) 1572 { 1573 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1574 unsigned int ret_freq = 0; 1575 1576 if (!cpufreq_driver->get) 1577 return ret_freq; 1578 1579 ret_freq = cpufreq_driver->get(cpu); 1580 1581 if (ret_freq && policy->cur && 1582 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1583 /* verify no discrepancy between actual and 1584 saved value exists */ 1585 if (unlikely(ret_freq != policy->cur)) { 1586 cpufreq_out_of_sync(cpu, policy->cur, ret_freq); 1587 schedule_work(&policy->update); 1588 } 1589 } 1590 1591 return ret_freq; 1592 } 1593 1594 /** 1595 * cpufreq_get - get the current CPU frequency (in kHz) 1596 * @cpu: CPU number 1597 * 1598 * Get the CPU current (static) CPU frequency 1599 */ 1600 unsigned int cpufreq_get(unsigned int cpu) 1601 { 1602 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1603 unsigned int ret_freq = 0; 1604 1605 if (policy) { 1606 down_read(&policy->rwsem); 1607 ret_freq = __cpufreq_get(cpu); 1608 up_read(&policy->rwsem); 1609 1610 cpufreq_cpu_put(policy); 1611 } 1612 1613 return ret_freq; 1614 } 1615 EXPORT_SYMBOL(cpufreq_get); 1616 1617 static struct subsys_interface cpufreq_interface = { 1618 .name = "cpufreq", 1619 .subsys = &cpu_subsys, 1620 .add_dev = cpufreq_add_dev, 1621 .remove_dev = cpufreq_remove_dev, 1622 }; 1623 1624 /* 1625 * In case platform wants some specific frequency to be configured 1626 * during suspend.. 1627 */ 1628 int cpufreq_generic_suspend(struct cpufreq_policy *policy) 1629 { 1630 int ret; 1631 1632 if (!policy->suspend_freq) { 1633 pr_err("%s: suspend_freq can't be zero\n", __func__); 1634 return -EINVAL; 1635 } 1636 1637 pr_debug("%s: Setting suspend-freq: %u\n", __func__, 1638 policy->suspend_freq); 1639 1640 ret = __cpufreq_driver_target(policy, policy->suspend_freq, 1641 CPUFREQ_RELATION_H); 1642 if (ret) 1643 pr_err("%s: unable to set suspend-freq: %u. err: %d\n", 1644 __func__, policy->suspend_freq, ret); 1645 1646 return ret; 1647 } 1648 EXPORT_SYMBOL(cpufreq_generic_suspend); 1649 1650 /** 1651 * cpufreq_suspend() - Suspend CPUFreq governors 1652 * 1653 * Called during system wide Suspend/Hibernate cycles for suspending governors 1654 * as some platforms can't change frequency after this point in suspend cycle. 1655 * Because some of the devices (like: i2c, regulators, etc) they use for 1656 * changing frequency are suspended quickly after this point. 1657 */ 1658 void cpufreq_suspend(void) 1659 { 1660 struct cpufreq_policy *policy; 1661 1662 if (!cpufreq_driver) 1663 return; 1664 1665 if (!has_target()) 1666 return; 1667 1668 pr_debug("%s: Suspending Governors\n", __func__); 1669 1670 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1671 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP)) 1672 pr_err("%s: Failed to stop governor for policy: %p\n", 1673 __func__, policy); 1674 else if (cpufreq_driver->suspend 1675 && cpufreq_driver->suspend(policy)) 1676 pr_err("%s: Failed to suspend driver: %p\n", __func__, 1677 policy); 1678 } 1679 1680 cpufreq_suspended = true; 1681 } 1682 1683 /** 1684 * cpufreq_resume() - Resume CPUFreq governors 1685 * 1686 * Called during system wide Suspend/Hibernate cycle for resuming governors that 1687 * are suspended with cpufreq_suspend(). 1688 */ 1689 void cpufreq_resume(void) 1690 { 1691 struct cpufreq_policy *policy; 1692 1693 if (!cpufreq_driver) 1694 return; 1695 1696 if (!has_target()) 1697 return; 1698 1699 pr_debug("%s: Resuming Governors\n", __func__); 1700 1701 cpufreq_suspended = false; 1702 1703 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1704 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) 1705 pr_err("%s: Failed to resume driver: %p\n", __func__, 1706 policy); 1707 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START) 1708 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS)) 1709 pr_err("%s: Failed to start governor for policy: %p\n", 1710 __func__, policy); 1711 1712 /* 1713 * schedule call cpufreq_update_policy() for boot CPU, i.e. last 1714 * policy in list. It will verify that the current freq is in 1715 * sync with what we believe it to be. 1716 */ 1717 if (list_is_last(&policy->policy_list, &cpufreq_policy_list)) 1718 schedule_work(&policy->update); 1719 } 1720 } 1721 1722 /** 1723 * cpufreq_get_current_driver - return current driver's name 1724 * 1725 * Return the name string of the currently loaded cpufreq driver 1726 * or NULL, if none. 1727 */ 1728 const char *cpufreq_get_current_driver(void) 1729 { 1730 if (cpufreq_driver) 1731 return cpufreq_driver->name; 1732 1733 return NULL; 1734 } 1735 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); 1736 1737 /********************************************************************* 1738 * NOTIFIER LISTS INTERFACE * 1739 *********************************************************************/ 1740 1741 /** 1742 * cpufreq_register_notifier - register a driver with cpufreq 1743 * @nb: notifier function to register 1744 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1745 * 1746 * Add a driver to one of two lists: either a list of drivers that 1747 * are notified about clock rate changes (once before and once after 1748 * the transition), or a list of drivers that are notified about 1749 * changes in cpufreq policy. 1750 * 1751 * This function may sleep, and has the same return conditions as 1752 * blocking_notifier_chain_register. 1753 */ 1754 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1755 { 1756 int ret; 1757 1758 if (cpufreq_disabled()) 1759 return -EINVAL; 1760 1761 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1762 1763 switch (list) { 1764 case CPUFREQ_TRANSITION_NOTIFIER: 1765 ret = srcu_notifier_chain_register( 1766 &cpufreq_transition_notifier_list, nb); 1767 break; 1768 case CPUFREQ_POLICY_NOTIFIER: 1769 ret = blocking_notifier_chain_register( 1770 &cpufreq_policy_notifier_list, nb); 1771 break; 1772 default: 1773 ret = -EINVAL; 1774 } 1775 1776 return ret; 1777 } 1778 EXPORT_SYMBOL(cpufreq_register_notifier); 1779 1780 /** 1781 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1782 * @nb: notifier block to be unregistered 1783 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1784 * 1785 * Remove a driver from the CPU frequency notifier list. 1786 * 1787 * This function may sleep, and has the same return conditions as 1788 * blocking_notifier_chain_unregister. 1789 */ 1790 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1791 { 1792 int ret; 1793 1794 if (cpufreq_disabled()) 1795 return -EINVAL; 1796 1797 switch (list) { 1798 case CPUFREQ_TRANSITION_NOTIFIER: 1799 ret = srcu_notifier_chain_unregister( 1800 &cpufreq_transition_notifier_list, nb); 1801 break; 1802 case CPUFREQ_POLICY_NOTIFIER: 1803 ret = blocking_notifier_chain_unregister( 1804 &cpufreq_policy_notifier_list, nb); 1805 break; 1806 default: 1807 ret = -EINVAL; 1808 } 1809 1810 return ret; 1811 } 1812 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1813 1814 1815 /********************************************************************* 1816 * GOVERNORS * 1817 *********************************************************************/ 1818 1819 /* Must set freqs->new to intermediate frequency */ 1820 static int __target_intermediate(struct cpufreq_policy *policy, 1821 struct cpufreq_freqs *freqs, int index) 1822 { 1823 int ret; 1824 1825 freqs->new = cpufreq_driver->get_intermediate(policy, index); 1826 1827 /* We don't need to switch to intermediate freq */ 1828 if (!freqs->new) 1829 return 0; 1830 1831 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", 1832 __func__, policy->cpu, freqs->old, freqs->new); 1833 1834 cpufreq_freq_transition_begin(policy, freqs); 1835 ret = cpufreq_driver->target_intermediate(policy, index); 1836 cpufreq_freq_transition_end(policy, freqs, ret); 1837 1838 if (ret) 1839 pr_err("%s: Failed to change to intermediate frequency: %d\n", 1840 __func__, ret); 1841 1842 return ret; 1843 } 1844 1845 static int __target_index(struct cpufreq_policy *policy, 1846 struct cpufreq_frequency_table *freq_table, int index) 1847 { 1848 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; 1849 unsigned int intermediate_freq = 0; 1850 int retval = -EINVAL; 1851 bool notify; 1852 1853 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); 1854 if (notify) { 1855 /* Handle switching to intermediate frequency */ 1856 if (cpufreq_driver->get_intermediate) { 1857 retval = __target_intermediate(policy, &freqs, index); 1858 if (retval) 1859 return retval; 1860 1861 intermediate_freq = freqs.new; 1862 /* Set old freq to intermediate */ 1863 if (intermediate_freq) 1864 freqs.old = freqs.new; 1865 } 1866 1867 freqs.new = freq_table[index].frequency; 1868 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", 1869 __func__, policy->cpu, freqs.old, freqs.new); 1870 1871 cpufreq_freq_transition_begin(policy, &freqs); 1872 } 1873 1874 retval = cpufreq_driver->target_index(policy, index); 1875 if (retval) 1876 pr_err("%s: Failed to change cpu frequency: %d\n", __func__, 1877 retval); 1878 1879 if (notify) { 1880 cpufreq_freq_transition_end(policy, &freqs, retval); 1881 1882 /* 1883 * Failed after setting to intermediate freq? Driver should have 1884 * reverted back to initial frequency and so should we. Check 1885 * here for intermediate_freq instead of get_intermediate, in 1886 * case we have't switched to intermediate freq at all. 1887 */ 1888 if (unlikely(retval && intermediate_freq)) { 1889 freqs.old = intermediate_freq; 1890 freqs.new = policy->restore_freq; 1891 cpufreq_freq_transition_begin(policy, &freqs); 1892 cpufreq_freq_transition_end(policy, &freqs, 0); 1893 } 1894 } 1895 1896 return retval; 1897 } 1898 1899 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1900 unsigned int target_freq, 1901 unsigned int relation) 1902 { 1903 unsigned int old_target_freq = target_freq; 1904 int retval = -EINVAL; 1905 1906 if (cpufreq_disabled()) 1907 return -ENODEV; 1908 1909 /* Make sure that target_freq is within supported range */ 1910 if (target_freq > policy->max) 1911 target_freq = policy->max; 1912 if (target_freq < policy->min) 1913 target_freq = policy->min; 1914 1915 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", 1916 policy->cpu, target_freq, relation, old_target_freq); 1917 1918 /* 1919 * This might look like a redundant call as we are checking it again 1920 * after finding index. But it is left intentionally for cases where 1921 * exactly same freq is called again and so we can save on few function 1922 * calls. 1923 */ 1924 if (target_freq == policy->cur) 1925 return 0; 1926 1927 /* Save last value to restore later on errors */ 1928 policy->restore_freq = policy->cur; 1929 1930 if (cpufreq_driver->target) 1931 retval = cpufreq_driver->target(policy, target_freq, relation); 1932 else if (cpufreq_driver->target_index) { 1933 struct cpufreq_frequency_table *freq_table; 1934 int index; 1935 1936 freq_table = cpufreq_frequency_get_table(policy->cpu); 1937 if (unlikely(!freq_table)) { 1938 pr_err("%s: Unable to find freq_table\n", __func__); 1939 goto out; 1940 } 1941 1942 retval = cpufreq_frequency_table_target(policy, freq_table, 1943 target_freq, relation, &index); 1944 if (unlikely(retval)) { 1945 pr_err("%s: Unable to find matching freq\n", __func__); 1946 goto out; 1947 } 1948 1949 if (freq_table[index].frequency == policy->cur) { 1950 retval = 0; 1951 goto out; 1952 } 1953 1954 retval = __target_index(policy, freq_table, index); 1955 } 1956 1957 out: 1958 return retval; 1959 } 1960 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1961 1962 int cpufreq_driver_target(struct cpufreq_policy *policy, 1963 unsigned int target_freq, 1964 unsigned int relation) 1965 { 1966 int ret = -EINVAL; 1967 1968 down_write(&policy->rwsem); 1969 1970 ret = __cpufreq_driver_target(policy, target_freq, relation); 1971 1972 up_write(&policy->rwsem); 1973 1974 return ret; 1975 } 1976 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1977 1978 /* 1979 * when "event" is CPUFREQ_GOV_LIMITS 1980 */ 1981 1982 static int __cpufreq_governor(struct cpufreq_policy *policy, 1983 unsigned int event) 1984 { 1985 int ret; 1986 1987 /* Only must be defined when default governor is known to have latency 1988 restrictions, like e.g. conservative or ondemand. 1989 That this is the case is already ensured in Kconfig 1990 */ 1991 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE 1992 struct cpufreq_governor *gov = &cpufreq_gov_performance; 1993 #else 1994 struct cpufreq_governor *gov = NULL; 1995 #endif 1996 1997 /* Don't start any governor operations if we are entering suspend */ 1998 if (cpufreq_suspended) 1999 return 0; 2000 2001 if (policy->governor->max_transition_latency && 2002 policy->cpuinfo.transition_latency > 2003 policy->governor->max_transition_latency) { 2004 if (!gov) 2005 return -EINVAL; 2006 else { 2007 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", 2008 policy->governor->name, gov->name); 2009 policy->governor = gov; 2010 } 2011 } 2012 2013 if (event == CPUFREQ_GOV_POLICY_INIT) 2014 if (!try_module_get(policy->governor->owner)) 2015 return -EINVAL; 2016 2017 pr_debug("__cpufreq_governor for CPU %u, event %u\n", 2018 policy->cpu, event); 2019 2020 mutex_lock(&cpufreq_governor_lock); 2021 if ((policy->governor_enabled && event == CPUFREQ_GOV_START) 2022 || (!policy->governor_enabled 2023 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { 2024 mutex_unlock(&cpufreq_governor_lock); 2025 return -EBUSY; 2026 } 2027 2028 if (event == CPUFREQ_GOV_STOP) 2029 policy->governor_enabled = false; 2030 else if (event == CPUFREQ_GOV_START) 2031 policy->governor_enabled = true; 2032 2033 mutex_unlock(&cpufreq_governor_lock); 2034 2035 ret = policy->governor->governor(policy, event); 2036 2037 if (!ret) { 2038 if (event == CPUFREQ_GOV_POLICY_INIT) 2039 policy->governor->initialized++; 2040 else if (event == CPUFREQ_GOV_POLICY_EXIT) 2041 policy->governor->initialized--; 2042 } else { 2043 /* Restore original values */ 2044 mutex_lock(&cpufreq_governor_lock); 2045 if (event == CPUFREQ_GOV_STOP) 2046 policy->governor_enabled = true; 2047 else if (event == CPUFREQ_GOV_START) 2048 policy->governor_enabled = false; 2049 mutex_unlock(&cpufreq_governor_lock); 2050 } 2051 2052 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || 2053 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) 2054 module_put(policy->governor->owner); 2055 2056 return ret; 2057 } 2058 2059 int cpufreq_register_governor(struct cpufreq_governor *governor) 2060 { 2061 int err; 2062 2063 if (!governor) 2064 return -EINVAL; 2065 2066 if (cpufreq_disabled()) 2067 return -ENODEV; 2068 2069 mutex_lock(&cpufreq_governor_mutex); 2070 2071 governor->initialized = 0; 2072 err = -EBUSY; 2073 if (__find_governor(governor->name) == NULL) { 2074 err = 0; 2075 list_add(&governor->governor_list, &cpufreq_governor_list); 2076 } 2077 2078 mutex_unlock(&cpufreq_governor_mutex); 2079 return err; 2080 } 2081 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 2082 2083 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 2084 { 2085 int cpu; 2086 2087 if (!governor) 2088 return; 2089 2090 if (cpufreq_disabled()) 2091 return; 2092 2093 for_each_present_cpu(cpu) { 2094 if (cpu_online(cpu)) 2095 continue; 2096 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name)) 2097 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0"); 2098 } 2099 2100 mutex_lock(&cpufreq_governor_mutex); 2101 list_del(&governor->governor_list); 2102 mutex_unlock(&cpufreq_governor_mutex); 2103 return; 2104 } 2105 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 2106 2107 2108 /********************************************************************* 2109 * POLICY INTERFACE * 2110 *********************************************************************/ 2111 2112 /** 2113 * cpufreq_get_policy - get the current cpufreq_policy 2114 * @policy: struct cpufreq_policy into which the current cpufreq_policy 2115 * is written 2116 * 2117 * Reads the current cpufreq policy. 2118 */ 2119 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 2120 { 2121 struct cpufreq_policy *cpu_policy; 2122 if (!policy) 2123 return -EINVAL; 2124 2125 cpu_policy = cpufreq_cpu_get(cpu); 2126 if (!cpu_policy) 2127 return -EINVAL; 2128 2129 memcpy(policy, cpu_policy, sizeof(*policy)); 2130 2131 cpufreq_cpu_put(cpu_policy); 2132 return 0; 2133 } 2134 EXPORT_SYMBOL(cpufreq_get_policy); 2135 2136 /* 2137 * policy : current policy. 2138 * new_policy: policy to be set. 2139 */ 2140 static int cpufreq_set_policy(struct cpufreq_policy *policy, 2141 struct cpufreq_policy *new_policy) 2142 { 2143 struct cpufreq_governor *old_gov; 2144 int ret; 2145 2146 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", 2147 new_policy->cpu, new_policy->min, new_policy->max); 2148 2149 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); 2150 2151 if (new_policy->min > policy->max || new_policy->max < policy->min) 2152 return -EINVAL; 2153 2154 /* verify the cpu speed can be set within this limit */ 2155 ret = cpufreq_driver->verify(new_policy); 2156 if (ret) 2157 return ret; 2158 2159 /* adjust if necessary - all reasons */ 2160 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2161 CPUFREQ_ADJUST, new_policy); 2162 2163 /* adjust if necessary - hardware incompatibility*/ 2164 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2165 CPUFREQ_INCOMPATIBLE, new_policy); 2166 2167 /* 2168 * verify the cpu speed can be set within this limit, which might be 2169 * different to the first one 2170 */ 2171 ret = cpufreq_driver->verify(new_policy); 2172 if (ret) 2173 return ret; 2174 2175 /* notification of the new policy */ 2176 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2177 CPUFREQ_NOTIFY, new_policy); 2178 2179 policy->min = new_policy->min; 2180 policy->max = new_policy->max; 2181 2182 pr_debug("new min and max freqs are %u - %u kHz\n", 2183 policy->min, policy->max); 2184 2185 if (cpufreq_driver->setpolicy) { 2186 policy->policy = new_policy->policy; 2187 pr_debug("setting range\n"); 2188 return cpufreq_driver->setpolicy(new_policy); 2189 } 2190 2191 if (new_policy->governor == policy->governor) 2192 goto out; 2193 2194 pr_debug("governor switch\n"); 2195 2196 /* save old, working values */ 2197 old_gov = policy->governor; 2198 /* end old governor */ 2199 if (old_gov) { 2200 __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 2201 up_write(&policy->rwsem); 2202 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2203 down_write(&policy->rwsem); 2204 } 2205 2206 /* start new governor */ 2207 policy->governor = new_policy->governor; 2208 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { 2209 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) 2210 goto out; 2211 2212 up_write(&policy->rwsem); 2213 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2214 down_write(&policy->rwsem); 2215 } 2216 2217 /* new governor failed, so re-start old one */ 2218 pr_debug("starting governor %s failed\n", policy->governor->name); 2219 if (old_gov) { 2220 policy->governor = old_gov; 2221 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); 2222 __cpufreq_governor(policy, CPUFREQ_GOV_START); 2223 } 2224 2225 return -EINVAL; 2226 2227 out: 2228 pr_debug("governor: change or update limits\n"); 2229 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2230 } 2231 2232 /** 2233 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 2234 * @cpu: CPU which shall be re-evaluated 2235 * 2236 * Useful for policy notifiers which have different necessities 2237 * at different times. 2238 */ 2239 int cpufreq_update_policy(unsigned int cpu) 2240 { 2241 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 2242 struct cpufreq_policy new_policy; 2243 int ret; 2244 2245 if (!policy) 2246 return -ENODEV; 2247 2248 down_write(&policy->rwsem); 2249 2250 pr_debug("updating policy for CPU %u\n", cpu); 2251 memcpy(&new_policy, policy, sizeof(*policy)); 2252 new_policy.min = policy->user_policy.min; 2253 new_policy.max = policy->user_policy.max; 2254 new_policy.policy = policy->user_policy.policy; 2255 new_policy.governor = policy->user_policy.governor; 2256 2257 /* 2258 * BIOS might change freq behind our back 2259 * -> ask driver for current freq and notify governors about a change 2260 */ 2261 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 2262 new_policy.cur = cpufreq_driver->get(cpu); 2263 if (WARN_ON(!new_policy.cur)) { 2264 ret = -EIO; 2265 goto unlock; 2266 } 2267 2268 if (!policy->cur) { 2269 pr_debug("Driver did not initialize current freq\n"); 2270 policy->cur = new_policy.cur; 2271 } else { 2272 if (policy->cur != new_policy.cur && has_target()) 2273 cpufreq_out_of_sync(cpu, policy->cur, 2274 new_policy.cur); 2275 } 2276 } 2277 2278 ret = cpufreq_set_policy(policy, &new_policy); 2279 2280 unlock: 2281 up_write(&policy->rwsem); 2282 2283 cpufreq_cpu_put(policy); 2284 return ret; 2285 } 2286 EXPORT_SYMBOL(cpufreq_update_policy); 2287 2288 static int cpufreq_cpu_callback(struct notifier_block *nfb, 2289 unsigned long action, void *hcpu) 2290 { 2291 unsigned int cpu = (unsigned long)hcpu; 2292 struct device *dev; 2293 2294 dev = get_cpu_device(cpu); 2295 if (dev) { 2296 switch (action & ~CPU_TASKS_FROZEN) { 2297 case CPU_ONLINE: 2298 __cpufreq_add_dev(dev, NULL); 2299 break; 2300 2301 case CPU_DOWN_PREPARE: 2302 __cpufreq_remove_dev_prepare(dev, NULL); 2303 break; 2304 2305 case CPU_POST_DEAD: 2306 __cpufreq_remove_dev_finish(dev, NULL); 2307 break; 2308 2309 case CPU_DOWN_FAILED: 2310 __cpufreq_add_dev(dev, NULL); 2311 break; 2312 } 2313 } 2314 return NOTIFY_OK; 2315 } 2316 2317 static struct notifier_block __refdata cpufreq_cpu_notifier = { 2318 .notifier_call = cpufreq_cpu_callback, 2319 }; 2320 2321 /********************************************************************* 2322 * BOOST * 2323 *********************************************************************/ 2324 static int cpufreq_boost_set_sw(int state) 2325 { 2326 struct cpufreq_frequency_table *freq_table; 2327 struct cpufreq_policy *policy; 2328 int ret = -EINVAL; 2329 2330 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 2331 freq_table = cpufreq_frequency_get_table(policy->cpu); 2332 if (freq_table) { 2333 ret = cpufreq_frequency_table_cpuinfo(policy, 2334 freq_table); 2335 if (ret) { 2336 pr_err("%s: Policy frequency update failed\n", 2337 __func__); 2338 break; 2339 } 2340 policy->user_policy.max = policy->max; 2341 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2342 } 2343 } 2344 2345 return ret; 2346 } 2347 2348 int cpufreq_boost_trigger_state(int state) 2349 { 2350 unsigned long flags; 2351 int ret = 0; 2352 2353 if (cpufreq_driver->boost_enabled == state) 2354 return 0; 2355 2356 write_lock_irqsave(&cpufreq_driver_lock, flags); 2357 cpufreq_driver->boost_enabled = state; 2358 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2359 2360 ret = cpufreq_driver->set_boost(state); 2361 if (ret) { 2362 write_lock_irqsave(&cpufreq_driver_lock, flags); 2363 cpufreq_driver->boost_enabled = !state; 2364 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2365 2366 pr_err("%s: Cannot %s BOOST\n", 2367 __func__, state ? "enable" : "disable"); 2368 } 2369 2370 return ret; 2371 } 2372 2373 int cpufreq_boost_supported(void) 2374 { 2375 if (likely(cpufreq_driver)) 2376 return cpufreq_driver->boost_supported; 2377 2378 return 0; 2379 } 2380 EXPORT_SYMBOL_GPL(cpufreq_boost_supported); 2381 2382 int cpufreq_boost_enabled(void) 2383 { 2384 return cpufreq_driver->boost_enabled; 2385 } 2386 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); 2387 2388 /********************************************************************* 2389 * REGISTER / UNREGISTER CPUFREQ DRIVER * 2390 *********************************************************************/ 2391 2392 /** 2393 * cpufreq_register_driver - register a CPU Frequency driver 2394 * @driver_data: A struct cpufreq_driver containing the values# 2395 * submitted by the CPU Frequency driver. 2396 * 2397 * Registers a CPU Frequency driver to this core code. This code 2398 * returns zero on success, -EBUSY when another driver got here first 2399 * (and isn't unregistered in the meantime). 2400 * 2401 */ 2402 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 2403 { 2404 unsigned long flags; 2405 int ret; 2406 2407 if (cpufreq_disabled()) 2408 return -ENODEV; 2409 2410 if (!driver_data || !driver_data->verify || !driver_data->init || 2411 !(driver_data->setpolicy || driver_data->target_index || 2412 driver_data->target) || 2413 (driver_data->setpolicy && (driver_data->target_index || 2414 driver_data->target)) || 2415 (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) 2416 return -EINVAL; 2417 2418 pr_debug("trying to register driver %s\n", driver_data->name); 2419 2420 if (driver_data->setpolicy) 2421 driver_data->flags |= CPUFREQ_CONST_LOOPS; 2422 2423 write_lock_irqsave(&cpufreq_driver_lock, flags); 2424 if (cpufreq_driver) { 2425 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2426 return -EEXIST; 2427 } 2428 cpufreq_driver = driver_data; 2429 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2430 2431 if (cpufreq_boost_supported()) { 2432 /* 2433 * Check if driver provides function to enable boost - 2434 * if not, use cpufreq_boost_set_sw as default 2435 */ 2436 if (!cpufreq_driver->set_boost) 2437 cpufreq_driver->set_boost = cpufreq_boost_set_sw; 2438 2439 ret = cpufreq_sysfs_create_file(&boost.attr); 2440 if (ret) { 2441 pr_err("%s: cannot register global BOOST sysfs file\n", 2442 __func__); 2443 goto err_null_driver; 2444 } 2445 } 2446 2447 ret = subsys_interface_register(&cpufreq_interface); 2448 if (ret) 2449 goto err_boost_unreg; 2450 2451 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { 2452 int i; 2453 ret = -ENODEV; 2454 2455 /* check for at least one working CPU */ 2456 for (i = 0; i < nr_cpu_ids; i++) 2457 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { 2458 ret = 0; 2459 break; 2460 } 2461 2462 /* if all ->init() calls failed, unregister */ 2463 if (ret) { 2464 pr_debug("no CPU initialized for driver %s\n", 2465 driver_data->name); 2466 goto err_if_unreg; 2467 } 2468 } 2469 2470 register_hotcpu_notifier(&cpufreq_cpu_notifier); 2471 pr_debug("driver %s up and running\n", driver_data->name); 2472 2473 return 0; 2474 err_if_unreg: 2475 subsys_interface_unregister(&cpufreq_interface); 2476 err_boost_unreg: 2477 if (cpufreq_boost_supported()) 2478 cpufreq_sysfs_remove_file(&boost.attr); 2479 err_null_driver: 2480 write_lock_irqsave(&cpufreq_driver_lock, flags); 2481 cpufreq_driver = NULL; 2482 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2483 return ret; 2484 } 2485 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 2486 2487 /** 2488 * cpufreq_unregister_driver - unregister the current CPUFreq driver 2489 * 2490 * Unregister the current CPUFreq driver. Only call this if you have 2491 * the right to do so, i.e. if you have succeeded in initialising before! 2492 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 2493 * currently not initialised. 2494 */ 2495 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 2496 { 2497 unsigned long flags; 2498 2499 if (!cpufreq_driver || (driver != cpufreq_driver)) 2500 return -EINVAL; 2501 2502 pr_debug("unregistering driver %s\n", driver->name); 2503 2504 subsys_interface_unregister(&cpufreq_interface); 2505 if (cpufreq_boost_supported()) 2506 cpufreq_sysfs_remove_file(&boost.attr); 2507 2508 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 2509 2510 down_write(&cpufreq_rwsem); 2511 write_lock_irqsave(&cpufreq_driver_lock, flags); 2512 2513 cpufreq_driver = NULL; 2514 2515 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2516 up_write(&cpufreq_rwsem); 2517 2518 return 0; 2519 } 2520 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 2521 2522 static int __init cpufreq_core_init(void) 2523 { 2524 if (cpufreq_disabled()) 2525 return -ENODEV; 2526 2527 cpufreq_global_kobject = kobject_create(); 2528 BUG_ON(!cpufreq_global_kobject); 2529 2530 return 0; 2531 } 2532 core_initcall(cpufreq_core_init); 2533