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 int update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu, 1080 struct device *cpu_dev) 1081 { 1082 int ret; 1083 1084 if (WARN_ON(cpu == policy->cpu)) 1085 return 0; 1086 1087 /* Move kobject to the new policy->cpu */ 1088 ret = kobject_move(&policy->kobj, &cpu_dev->kobj); 1089 if (ret) { 1090 pr_err("%s: Failed to move kobj: %d\n", __func__, ret); 1091 return ret; 1092 } 1093 1094 down_write(&policy->rwsem); 1095 1096 policy->last_cpu = policy->cpu; 1097 policy->cpu = cpu; 1098 1099 up_write(&policy->rwsem); 1100 1101 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1102 CPUFREQ_UPDATE_POLICY_CPU, policy); 1103 1104 return 0; 1105 } 1106 1107 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1108 { 1109 unsigned int j, cpu = dev->id; 1110 int ret = -ENOMEM; 1111 struct cpufreq_policy *policy; 1112 unsigned long flags; 1113 bool recover_policy = cpufreq_suspended; 1114 #ifdef CONFIG_HOTPLUG_CPU 1115 struct cpufreq_policy *tpolicy; 1116 #endif 1117 1118 if (cpu_is_offline(cpu)) 1119 return 0; 1120 1121 pr_debug("adding CPU %u\n", cpu); 1122 1123 #ifdef CONFIG_SMP 1124 /* check whether a different CPU already registered this 1125 * CPU because it is in the same boat. */ 1126 policy = cpufreq_cpu_get(cpu); 1127 if (unlikely(policy)) { 1128 cpufreq_cpu_put(policy); 1129 return 0; 1130 } 1131 #endif 1132 1133 if (!down_read_trylock(&cpufreq_rwsem)) 1134 return 0; 1135 1136 #ifdef CONFIG_HOTPLUG_CPU 1137 /* Check if this cpu was hot-unplugged earlier and has siblings */ 1138 read_lock_irqsave(&cpufreq_driver_lock, flags); 1139 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { 1140 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { 1141 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1142 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev); 1143 up_read(&cpufreq_rwsem); 1144 return ret; 1145 } 1146 } 1147 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1148 #endif 1149 1150 /* 1151 * Restore the saved policy when doing light-weight init and fall back 1152 * to the full init if that fails. 1153 */ 1154 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL; 1155 if (!policy) { 1156 recover_policy = false; 1157 policy = cpufreq_policy_alloc(); 1158 if (!policy) 1159 goto nomem_out; 1160 } 1161 1162 /* 1163 * In the resume path, since we restore a saved policy, the assignment 1164 * to policy->cpu is like an update of the existing policy, rather than 1165 * the creation of a brand new one. So we need to perform this update 1166 * by invoking update_policy_cpu(). 1167 */ 1168 if (recover_policy && cpu != policy->cpu) 1169 WARN_ON(update_policy_cpu(policy, cpu, dev)); 1170 else 1171 policy->cpu = cpu; 1172 1173 cpumask_copy(policy->cpus, cpumask_of(cpu)); 1174 1175 init_completion(&policy->kobj_unregister); 1176 INIT_WORK(&policy->update, handle_update); 1177 1178 /* call driver. From then on the cpufreq must be able 1179 * to accept all calls to ->verify and ->setpolicy for this CPU 1180 */ 1181 ret = cpufreq_driver->init(policy); 1182 if (ret) { 1183 pr_debug("initialization failed\n"); 1184 goto err_set_policy_cpu; 1185 } 1186 1187 /* related cpus should atleast have policy->cpus */ 1188 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); 1189 1190 /* 1191 * affected cpus must always be the one, which are online. We aren't 1192 * managing offline cpus here. 1193 */ 1194 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); 1195 1196 if (!recover_policy) { 1197 policy->user_policy.min = policy->min; 1198 policy->user_policy.max = policy->max; 1199 } 1200 1201 down_write(&policy->rwsem); 1202 write_lock_irqsave(&cpufreq_driver_lock, flags); 1203 for_each_cpu(j, policy->cpus) 1204 per_cpu(cpufreq_cpu_data, j) = policy; 1205 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1206 1207 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 1208 policy->cur = cpufreq_driver->get(policy->cpu); 1209 if (!policy->cur) { 1210 pr_err("%s: ->get() failed\n", __func__); 1211 goto err_get_freq; 1212 } 1213 } 1214 1215 /* 1216 * Sometimes boot loaders set CPU frequency to a value outside of 1217 * frequency table present with cpufreq core. In such cases CPU might be 1218 * unstable if it has to run on that frequency for long duration of time 1219 * and so its better to set it to a frequency which is specified in 1220 * freq-table. This also makes cpufreq stats inconsistent as 1221 * cpufreq-stats would fail to register because current frequency of CPU 1222 * isn't found in freq-table. 1223 * 1224 * Because we don't want this change to effect boot process badly, we go 1225 * for the next freq which is >= policy->cur ('cur' must be set by now, 1226 * otherwise we will end up setting freq to lowest of the table as 'cur' 1227 * is initialized to zero). 1228 * 1229 * We are passing target-freq as "policy->cur - 1" otherwise 1230 * __cpufreq_driver_target() would simply fail, as policy->cur will be 1231 * equal to target-freq. 1232 */ 1233 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) 1234 && has_target()) { 1235 /* Are we running at unknown frequency ? */ 1236 ret = cpufreq_frequency_table_get_index(policy, policy->cur); 1237 if (ret == -EINVAL) { 1238 /* Warn user and fix it */ 1239 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", 1240 __func__, policy->cpu, policy->cur); 1241 ret = __cpufreq_driver_target(policy, policy->cur - 1, 1242 CPUFREQ_RELATION_L); 1243 1244 /* 1245 * Reaching here after boot in a few seconds may not 1246 * mean that system will remain stable at "unknown" 1247 * frequency for longer duration. Hence, a BUG_ON(). 1248 */ 1249 BUG_ON(ret); 1250 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", 1251 __func__, policy->cpu, policy->cur); 1252 } 1253 } 1254 1255 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1256 CPUFREQ_START, policy); 1257 1258 if (!recover_policy) { 1259 ret = cpufreq_add_dev_interface(policy, dev); 1260 if (ret) 1261 goto err_out_unregister; 1262 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1263 CPUFREQ_CREATE_POLICY, policy); 1264 } 1265 1266 write_lock_irqsave(&cpufreq_driver_lock, flags); 1267 list_add(&policy->policy_list, &cpufreq_policy_list); 1268 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1269 1270 cpufreq_init_policy(policy); 1271 1272 if (!recover_policy) { 1273 policy->user_policy.policy = policy->policy; 1274 policy->user_policy.governor = policy->governor; 1275 } 1276 up_write(&policy->rwsem); 1277 1278 kobject_uevent(&policy->kobj, KOBJ_ADD); 1279 up_read(&cpufreq_rwsem); 1280 1281 pr_debug("initialization complete\n"); 1282 1283 return 0; 1284 1285 err_out_unregister: 1286 err_get_freq: 1287 write_lock_irqsave(&cpufreq_driver_lock, flags); 1288 for_each_cpu(j, policy->cpus) 1289 per_cpu(cpufreq_cpu_data, j) = NULL; 1290 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1291 1292 up_write(&policy->rwsem); 1293 1294 if (cpufreq_driver->exit) 1295 cpufreq_driver->exit(policy); 1296 err_set_policy_cpu: 1297 if (recover_policy) { 1298 /* Do not leave stale fallback data behind. */ 1299 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL; 1300 cpufreq_policy_put_kobj(policy); 1301 } 1302 cpufreq_policy_free(policy); 1303 1304 nomem_out: 1305 up_read(&cpufreq_rwsem); 1306 1307 return ret; 1308 } 1309 1310 /** 1311 * cpufreq_add_dev - add a CPU device 1312 * 1313 * Adds the cpufreq interface for a CPU device. 1314 * 1315 * The Oracle says: try running cpufreq registration/unregistration concurrently 1316 * with with cpu hotplugging and all hell will break loose. Tried to clean this 1317 * mess up, but more thorough testing is needed. - Mathieu 1318 */ 1319 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1320 { 1321 return __cpufreq_add_dev(dev, sif); 1322 } 1323 1324 static int __cpufreq_remove_dev_prepare(struct device *dev, 1325 struct subsys_interface *sif) 1326 { 1327 unsigned int cpu = dev->id, cpus; 1328 int ret; 1329 unsigned long flags; 1330 struct cpufreq_policy *policy; 1331 1332 pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 1333 1334 write_lock_irqsave(&cpufreq_driver_lock, flags); 1335 1336 policy = per_cpu(cpufreq_cpu_data, cpu); 1337 1338 /* Save the policy somewhere when doing a light-weight tear-down */ 1339 if (cpufreq_suspended) 1340 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy; 1341 1342 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1343 1344 if (!policy) { 1345 pr_debug("%s: No cpu_data found\n", __func__); 1346 return -EINVAL; 1347 } 1348 1349 if (has_target()) { 1350 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 1351 if (ret) { 1352 pr_err("%s: Failed to stop governor\n", __func__); 1353 return ret; 1354 } 1355 } 1356 1357 if (!cpufreq_driver->setpolicy) 1358 strncpy(per_cpu(cpufreq_cpu_governor, cpu), 1359 policy->governor->name, CPUFREQ_NAME_LEN); 1360 1361 down_read(&policy->rwsem); 1362 cpus = cpumask_weight(policy->cpus); 1363 up_read(&policy->rwsem); 1364 1365 if (cpu != policy->cpu) { 1366 sysfs_remove_link(&dev->kobj, "cpufreq"); 1367 } else if (cpus > 1) { 1368 /* Nominate new CPU */ 1369 int new_cpu = cpumask_any_but(policy->cpus, cpu); 1370 struct device *cpu_dev = get_cpu_device(new_cpu); 1371 1372 sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); 1373 ret = update_policy_cpu(policy, new_cpu, cpu_dev); 1374 if (ret) { 1375 if (sysfs_create_link(&cpu_dev->kobj, &policy->kobj, 1376 "cpufreq")) 1377 pr_err("%s: Failed to restore kobj link to cpu:%d\n", 1378 __func__, cpu_dev->id); 1379 return ret; 1380 } 1381 1382 if (!cpufreq_suspended) 1383 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", 1384 __func__, new_cpu, cpu); 1385 } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) { 1386 cpufreq_driver->stop_cpu(policy); 1387 } 1388 1389 return 0; 1390 } 1391 1392 static int __cpufreq_remove_dev_finish(struct device *dev, 1393 struct subsys_interface *sif) 1394 { 1395 unsigned int cpu = dev->id, cpus; 1396 int ret; 1397 unsigned long flags; 1398 struct cpufreq_policy *policy; 1399 1400 read_lock_irqsave(&cpufreq_driver_lock, flags); 1401 policy = per_cpu(cpufreq_cpu_data, cpu); 1402 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1403 1404 if (!policy) { 1405 pr_debug("%s: No cpu_data found\n", __func__); 1406 return -EINVAL; 1407 } 1408 1409 down_write(&policy->rwsem); 1410 cpus = cpumask_weight(policy->cpus); 1411 1412 if (cpus > 1) 1413 cpumask_clear_cpu(cpu, policy->cpus); 1414 up_write(&policy->rwsem); 1415 1416 /* If cpu is last user of policy, free policy */ 1417 if (cpus == 1) { 1418 if (has_target()) { 1419 ret = __cpufreq_governor(policy, 1420 CPUFREQ_GOV_POLICY_EXIT); 1421 if (ret) { 1422 pr_err("%s: Failed to exit governor\n", 1423 __func__); 1424 return ret; 1425 } 1426 } 1427 1428 if (!cpufreq_suspended) 1429 cpufreq_policy_put_kobj(policy); 1430 1431 /* 1432 * Perform the ->exit() even during light-weight tear-down, 1433 * since this is a core component, and is essential for the 1434 * subsequent light-weight ->init() to succeed. 1435 */ 1436 if (cpufreq_driver->exit) 1437 cpufreq_driver->exit(policy); 1438 1439 /* Remove policy from list of active policies */ 1440 write_lock_irqsave(&cpufreq_driver_lock, flags); 1441 list_del(&policy->policy_list); 1442 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1443 1444 if (!cpufreq_suspended) 1445 cpufreq_policy_free(policy); 1446 } else if (has_target()) { 1447 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); 1448 if (!ret) 1449 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 1450 1451 if (ret) { 1452 pr_err("%s: Failed to start governor\n", __func__); 1453 return ret; 1454 } 1455 } 1456 1457 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1458 return 0; 1459 } 1460 1461 /** 1462 * cpufreq_remove_dev - remove a CPU device 1463 * 1464 * Removes the cpufreq interface for a CPU device. 1465 */ 1466 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 1467 { 1468 unsigned int cpu = dev->id; 1469 int ret; 1470 1471 if (cpu_is_offline(cpu)) 1472 return 0; 1473 1474 ret = __cpufreq_remove_dev_prepare(dev, sif); 1475 1476 if (!ret) 1477 ret = __cpufreq_remove_dev_finish(dev, sif); 1478 1479 return ret; 1480 } 1481 1482 static void handle_update(struct work_struct *work) 1483 { 1484 struct cpufreq_policy *policy = 1485 container_of(work, struct cpufreq_policy, update); 1486 unsigned int cpu = policy->cpu; 1487 pr_debug("handle_update for cpu %u called\n", cpu); 1488 cpufreq_update_policy(cpu); 1489 } 1490 1491 /** 1492 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're 1493 * in deep trouble. 1494 * @cpu: cpu number 1495 * @old_freq: CPU frequency the kernel thinks the CPU runs at 1496 * @new_freq: CPU frequency the CPU actually runs at 1497 * 1498 * We adjust to current frequency first, and need to clean up later. 1499 * So either call to cpufreq_update_policy() or schedule handle_update()). 1500 */ 1501 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, 1502 unsigned int new_freq) 1503 { 1504 struct cpufreq_policy *policy; 1505 struct cpufreq_freqs freqs; 1506 unsigned long flags; 1507 1508 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n", 1509 old_freq, new_freq); 1510 1511 freqs.old = old_freq; 1512 freqs.new = new_freq; 1513 1514 read_lock_irqsave(&cpufreq_driver_lock, flags); 1515 policy = per_cpu(cpufreq_cpu_data, cpu); 1516 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1517 1518 cpufreq_freq_transition_begin(policy, &freqs); 1519 cpufreq_freq_transition_end(policy, &freqs, 0); 1520 } 1521 1522 /** 1523 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1524 * @cpu: CPU number 1525 * 1526 * This is the last known freq, without actually getting it from the driver. 1527 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1528 */ 1529 unsigned int cpufreq_quick_get(unsigned int cpu) 1530 { 1531 struct cpufreq_policy *policy; 1532 unsigned int ret_freq = 0; 1533 1534 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) 1535 return cpufreq_driver->get(cpu); 1536 1537 policy = cpufreq_cpu_get(cpu); 1538 if (policy) { 1539 ret_freq = policy->cur; 1540 cpufreq_cpu_put(policy); 1541 } 1542 1543 return ret_freq; 1544 } 1545 EXPORT_SYMBOL(cpufreq_quick_get); 1546 1547 /** 1548 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU 1549 * @cpu: CPU number 1550 * 1551 * Just return the max possible frequency for a given CPU. 1552 */ 1553 unsigned int cpufreq_quick_get_max(unsigned int cpu) 1554 { 1555 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1556 unsigned int ret_freq = 0; 1557 1558 if (policy) { 1559 ret_freq = policy->max; 1560 cpufreq_cpu_put(policy); 1561 } 1562 1563 return ret_freq; 1564 } 1565 EXPORT_SYMBOL(cpufreq_quick_get_max); 1566 1567 static unsigned int __cpufreq_get(unsigned int cpu) 1568 { 1569 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1570 unsigned int ret_freq = 0; 1571 1572 if (!cpufreq_driver->get) 1573 return ret_freq; 1574 1575 ret_freq = cpufreq_driver->get(cpu); 1576 1577 if (ret_freq && policy->cur && 1578 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1579 /* verify no discrepancy between actual and 1580 saved value exists */ 1581 if (unlikely(ret_freq != policy->cur)) { 1582 cpufreq_out_of_sync(cpu, policy->cur, ret_freq); 1583 schedule_work(&policy->update); 1584 } 1585 } 1586 1587 return ret_freq; 1588 } 1589 1590 /** 1591 * cpufreq_get - get the current CPU frequency (in kHz) 1592 * @cpu: CPU number 1593 * 1594 * Get the CPU current (static) CPU frequency 1595 */ 1596 unsigned int cpufreq_get(unsigned int cpu) 1597 { 1598 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1599 unsigned int ret_freq = 0; 1600 1601 if (policy) { 1602 down_read(&policy->rwsem); 1603 ret_freq = __cpufreq_get(cpu); 1604 up_read(&policy->rwsem); 1605 1606 cpufreq_cpu_put(policy); 1607 } 1608 1609 return ret_freq; 1610 } 1611 EXPORT_SYMBOL(cpufreq_get); 1612 1613 static struct subsys_interface cpufreq_interface = { 1614 .name = "cpufreq", 1615 .subsys = &cpu_subsys, 1616 .add_dev = cpufreq_add_dev, 1617 .remove_dev = cpufreq_remove_dev, 1618 }; 1619 1620 /* 1621 * In case platform wants some specific frequency to be configured 1622 * during suspend.. 1623 */ 1624 int cpufreq_generic_suspend(struct cpufreq_policy *policy) 1625 { 1626 int ret; 1627 1628 if (!policy->suspend_freq) { 1629 pr_err("%s: suspend_freq can't be zero\n", __func__); 1630 return -EINVAL; 1631 } 1632 1633 pr_debug("%s: Setting suspend-freq: %u\n", __func__, 1634 policy->suspend_freq); 1635 1636 ret = __cpufreq_driver_target(policy, policy->suspend_freq, 1637 CPUFREQ_RELATION_H); 1638 if (ret) 1639 pr_err("%s: unable to set suspend-freq: %u. err: %d\n", 1640 __func__, policy->suspend_freq, ret); 1641 1642 return ret; 1643 } 1644 EXPORT_SYMBOL(cpufreq_generic_suspend); 1645 1646 /** 1647 * cpufreq_suspend() - Suspend CPUFreq governors 1648 * 1649 * Called during system wide Suspend/Hibernate cycles for suspending governors 1650 * as some platforms can't change frequency after this point in suspend cycle. 1651 * Because some of the devices (like: i2c, regulators, etc) they use for 1652 * changing frequency are suspended quickly after this point. 1653 */ 1654 void cpufreq_suspend(void) 1655 { 1656 struct cpufreq_policy *policy; 1657 1658 if (!cpufreq_driver) 1659 return; 1660 1661 if (!has_target()) 1662 goto suspend; 1663 1664 pr_debug("%s: Suspending Governors\n", __func__); 1665 1666 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1667 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP)) 1668 pr_err("%s: Failed to stop governor for policy: %p\n", 1669 __func__, policy); 1670 else if (cpufreq_driver->suspend 1671 && cpufreq_driver->suspend(policy)) 1672 pr_err("%s: Failed to suspend driver: %p\n", __func__, 1673 policy); 1674 } 1675 1676 suspend: 1677 cpufreq_suspended = true; 1678 } 1679 1680 /** 1681 * cpufreq_resume() - Resume CPUFreq governors 1682 * 1683 * Called during system wide Suspend/Hibernate cycle for resuming governors that 1684 * are suspended with cpufreq_suspend(). 1685 */ 1686 void cpufreq_resume(void) 1687 { 1688 struct cpufreq_policy *policy; 1689 1690 if (!cpufreq_driver) 1691 return; 1692 1693 cpufreq_suspended = false; 1694 1695 if (!has_target()) 1696 return; 1697 1698 pr_debug("%s: Resuming Governors\n", __func__); 1699 1700 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1701 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) 1702 pr_err("%s: Failed to resume driver: %p\n", __func__, 1703 policy); 1704 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START) 1705 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS)) 1706 pr_err("%s: Failed to start governor for policy: %p\n", 1707 __func__, policy); 1708 1709 /* 1710 * schedule call cpufreq_update_policy() for boot CPU, i.e. last 1711 * policy in list. It will verify that the current freq is in 1712 * sync with what we believe it to be. 1713 */ 1714 if (list_is_last(&policy->policy_list, &cpufreq_policy_list)) 1715 schedule_work(&policy->update); 1716 } 1717 } 1718 1719 /** 1720 * cpufreq_get_current_driver - return current driver's name 1721 * 1722 * Return the name string of the currently loaded cpufreq driver 1723 * or NULL, if none. 1724 */ 1725 const char *cpufreq_get_current_driver(void) 1726 { 1727 if (cpufreq_driver) 1728 return cpufreq_driver->name; 1729 1730 return NULL; 1731 } 1732 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); 1733 1734 /********************************************************************* 1735 * NOTIFIER LISTS INTERFACE * 1736 *********************************************************************/ 1737 1738 /** 1739 * cpufreq_register_notifier - register a driver with cpufreq 1740 * @nb: notifier function to register 1741 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1742 * 1743 * Add a driver to one of two lists: either a list of drivers that 1744 * are notified about clock rate changes (once before and once after 1745 * the transition), or a list of drivers that are notified about 1746 * changes in cpufreq policy. 1747 * 1748 * This function may sleep, and has the same return conditions as 1749 * blocking_notifier_chain_register. 1750 */ 1751 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1752 { 1753 int ret; 1754 1755 if (cpufreq_disabled()) 1756 return -EINVAL; 1757 1758 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1759 1760 switch (list) { 1761 case CPUFREQ_TRANSITION_NOTIFIER: 1762 ret = srcu_notifier_chain_register( 1763 &cpufreq_transition_notifier_list, nb); 1764 break; 1765 case CPUFREQ_POLICY_NOTIFIER: 1766 ret = blocking_notifier_chain_register( 1767 &cpufreq_policy_notifier_list, nb); 1768 break; 1769 default: 1770 ret = -EINVAL; 1771 } 1772 1773 return ret; 1774 } 1775 EXPORT_SYMBOL(cpufreq_register_notifier); 1776 1777 /** 1778 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1779 * @nb: notifier block to be unregistered 1780 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1781 * 1782 * Remove a driver from the CPU frequency notifier list. 1783 * 1784 * This function may sleep, and has the same return conditions as 1785 * blocking_notifier_chain_unregister. 1786 */ 1787 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1788 { 1789 int ret; 1790 1791 if (cpufreq_disabled()) 1792 return -EINVAL; 1793 1794 switch (list) { 1795 case CPUFREQ_TRANSITION_NOTIFIER: 1796 ret = srcu_notifier_chain_unregister( 1797 &cpufreq_transition_notifier_list, nb); 1798 break; 1799 case CPUFREQ_POLICY_NOTIFIER: 1800 ret = blocking_notifier_chain_unregister( 1801 &cpufreq_policy_notifier_list, nb); 1802 break; 1803 default: 1804 ret = -EINVAL; 1805 } 1806 1807 return ret; 1808 } 1809 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1810 1811 1812 /********************************************************************* 1813 * GOVERNORS * 1814 *********************************************************************/ 1815 1816 /* Must set freqs->new to intermediate frequency */ 1817 static int __target_intermediate(struct cpufreq_policy *policy, 1818 struct cpufreq_freqs *freqs, int index) 1819 { 1820 int ret; 1821 1822 freqs->new = cpufreq_driver->get_intermediate(policy, index); 1823 1824 /* We don't need to switch to intermediate freq */ 1825 if (!freqs->new) 1826 return 0; 1827 1828 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", 1829 __func__, policy->cpu, freqs->old, freqs->new); 1830 1831 cpufreq_freq_transition_begin(policy, freqs); 1832 ret = cpufreq_driver->target_intermediate(policy, index); 1833 cpufreq_freq_transition_end(policy, freqs, ret); 1834 1835 if (ret) 1836 pr_err("%s: Failed to change to intermediate frequency: %d\n", 1837 __func__, ret); 1838 1839 return ret; 1840 } 1841 1842 static int __target_index(struct cpufreq_policy *policy, 1843 struct cpufreq_frequency_table *freq_table, int index) 1844 { 1845 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; 1846 unsigned int intermediate_freq = 0; 1847 int retval = -EINVAL; 1848 bool notify; 1849 1850 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); 1851 if (notify) { 1852 /* Handle switching to intermediate frequency */ 1853 if (cpufreq_driver->get_intermediate) { 1854 retval = __target_intermediate(policy, &freqs, index); 1855 if (retval) 1856 return retval; 1857 1858 intermediate_freq = freqs.new; 1859 /* Set old freq to intermediate */ 1860 if (intermediate_freq) 1861 freqs.old = freqs.new; 1862 } 1863 1864 freqs.new = freq_table[index].frequency; 1865 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", 1866 __func__, policy->cpu, freqs.old, freqs.new); 1867 1868 cpufreq_freq_transition_begin(policy, &freqs); 1869 } 1870 1871 retval = cpufreq_driver->target_index(policy, index); 1872 if (retval) 1873 pr_err("%s: Failed to change cpu frequency: %d\n", __func__, 1874 retval); 1875 1876 if (notify) { 1877 cpufreq_freq_transition_end(policy, &freqs, retval); 1878 1879 /* 1880 * Failed after setting to intermediate freq? Driver should have 1881 * reverted back to initial frequency and so should we. Check 1882 * here for intermediate_freq instead of get_intermediate, in 1883 * case we have't switched to intermediate freq at all. 1884 */ 1885 if (unlikely(retval && intermediate_freq)) { 1886 freqs.old = intermediate_freq; 1887 freqs.new = policy->restore_freq; 1888 cpufreq_freq_transition_begin(policy, &freqs); 1889 cpufreq_freq_transition_end(policy, &freqs, 0); 1890 } 1891 } 1892 1893 return retval; 1894 } 1895 1896 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1897 unsigned int target_freq, 1898 unsigned int relation) 1899 { 1900 unsigned int old_target_freq = target_freq; 1901 int retval = -EINVAL; 1902 1903 if (cpufreq_disabled()) 1904 return -ENODEV; 1905 1906 /* Make sure that target_freq is within supported range */ 1907 if (target_freq > policy->max) 1908 target_freq = policy->max; 1909 if (target_freq < policy->min) 1910 target_freq = policy->min; 1911 1912 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", 1913 policy->cpu, target_freq, relation, old_target_freq); 1914 1915 /* 1916 * This might look like a redundant call as we are checking it again 1917 * after finding index. But it is left intentionally for cases where 1918 * exactly same freq is called again and so we can save on few function 1919 * calls. 1920 */ 1921 if (target_freq == policy->cur) 1922 return 0; 1923 1924 /* Save last value to restore later on errors */ 1925 policy->restore_freq = policy->cur; 1926 1927 if (cpufreq_driver->target) 1928 retval = cpufreq_driver->target(policy, target_freq, relation); 1929 else if (cpufreq_driver->target_index) { 1930 struct cpufreq_frequency_table *freq_table; 1931 int index; 1932 1933 freq_table = cpufreq_frequency_get_table(policy->cpu); 1934 if (unlikely(!freq_table)) { 1935 pr_err("%s: Unable to find freq_table\n", __func__); 1936 goto out; 1937 } 1938 1939 retval = cpufreq_frequency_table_target(policy, freq_table, 1940 target_freq, relation, &index); 1941 if (unlikely(retval)) { 1942 pr_err("%s: Unable to find matching freq\n", __func__); 1943 goto out; 1944 } 1945 1946 if (freq_table[index].frequency == policy->cur) { 1947 retval = 0; 1948 goto out; 1949 } 1950 1951 retval = __target_index(policy, freq_table, index); 1952 } 1953 1954 out: 1955 return retval; 1956 } 1957 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1958 1959 int cpufreq_driver_target(struct cpufreq_policy *policy, 1960 unsigned int target_freq, 1961 unsigned int relation) 1962 { 1963 int ret = -EINVAL; 1964 1965 down_write(&policy->rwsem); 1966 1967 ret = __cpufreq_driver_target(policy, target_freq, relation); 1968 1969 up_write(&policy->rwsem); 1970 1971 return ret; 1972 } 1973 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1974 1975 /* 1976 * when "event" is CPUFREQ_GOV_LIMITS 1977 */ 1978 1979 static int __cpufreq_governor(struct cpufreq_policy *policy, 1980 unsigned int event) 1981 { 1982 int ret; 1983 1984 /* Only must be defined when default governor is known to have latency 1985 restrictions, like e.g. conservative or ondemand. 1986 That this is the case is already ensured in Kconfig 1987 */ 1988 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE 1989 struct cpufreq_governor *gov = &cpufreq_gov_performance; 1990 #else 1991 struct cpufreq_governor *gov = NULL; 1992 #endif 1993 1994 /* Don't start any governor operations if we are entering suspend */ 1995 if (cpufreq_suspended) 1996 return 0; 1997 1998 if (policy->governor->max_transition_latency && 1999 policy->cpuinfo.transition_latency > 2000 policy->governor->max_transition_latency) { 2001 if (!gov) 2002 return -EINVAL; 2003 else { 2004 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", 2005 policy->governor->name, gov->name); 2006 policy->governor = gov; 2007 } 2008 } 2009 2010 if (event == CPUFREQ_GOV_POLICY_INIT) 2011 if (!try_module_get(policy->governor->owner)) 2012 return -EINVAL; 2013 2014 pr_debug("__cpufreq_governor for CPU %u, event %u\n", 2015 policy->cpu, event); 2016 2017 mutex_lock(&cpufreq_governor_lock); 2018 if ((policy->governor_enabled && event == CPUFREQ_GOV_START) 2019 || (!policy->governor_enabled 2020 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { 2021 mutex_unlock(&cpufreq_governor_lock); 2022 return -EBUSY; 2023 } 2024 2025 if (event == CPUFREQ_GOV_STOP) 2026 policy->governor_enabled = false; 2027 else if (event == CPUFREQ_GOV_START) 2028 policy->governor_enabled = true; 2029 2030 mutex_unlock(&cpufreq_governor_lock); 2031 2032 ret = policy->governor->governor(policy, event); 2033 2034 if (!ret) { 2035 if (event == CPUFREQ_GOV_POLICY_INIT) 2036 policy->governor->initialized++; 2037 else if (event == CPUFREQ_GOV_POLICY_EXIT) 2038 policy->governor->initialized--; 2039 } else { 2040 /* Restore original values */ 2041 mutex_lock(&cpufreq_governor_lock); 2042 if (event == CPUFREQ_GOV_STOP) 2043 policy->governor_enabled = true; 2044 else if (event == CPUFREQ_GOV_START) 2045 policy->governor_enabled = false; 2046 mutex_unlock(&cpufreq_governor_lock); 2047 } 2048 2049 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || 2050 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) 2051 module_put(policy->governor->owner); 2052 2053 return ret; 2054 } 2055 2056 int cpufreq_register_governor(struct cpufreq_governor *governor) 2057 { 2058 int err; 2059 2060 if (!governor) 2061 return -EINVAL; 2062 2063 if (cpufreq_disabled()) 2064 return -ENODEV; 2065 2066 mutex_lock(&cpufreq_governor_mutex); 2067 2068 governor->initialized = 0; 2069 err = -EBUSY; 2070 if (__find_governor(governor->name) == NULL) { 2071 err = 0; 2072 list_add(&governor->governor_list, &cpufreq_governor_list); 2073 } 2074 2075 mutex_unlock(&cpufreq_governor_mutex); 2076 return err; 2077 } 2078 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 2079 2080 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 2081 { 2082 int cpu; 2083 2084 if (!governor) 2085 return; 2086 2087 if (cpufreq_disabled()) 2088 return; 2089 2090 for_each_present_cpu(cpu) { 2091 if (cpu_online(cpu)) 2092 continue; 2093 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name)) 2094 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0"); 2095 } 2096 2097 mutex_lock(&cpufreq_governor_mutex); 2098 list_del(&governor->governor_list); 2099 mutex_unlock(&cpufreq_governor_mutex); 2100 return; 2101 } 2102 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 2103 2104 2105 /********************************************************************* 2106 * POLICY INTERFACE * 2107 *********************************************************************/ 2108 2109 /** 2110 * cpufreq_get_policy - get the current cpufreq_policy 2111 * @policy: struct cpufreq_policy into which the current cpufreq_policy 2112 * is written 2113 * 2114 * Reads the current cpufreq policy. 2115 */ 2116 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 2117 { 2118 struct cpufreq_policy *cpu_policy; 2119 if (!policy) 2120 return -EINVAL; 2121 2122 cpu_policy = cpufreq_cpu_get(cpu); 2123 if (!cpu_policy) 2124 return -EINVAL; 2125 2126 memcpy(policy, cpu_policy, sizeof(*policy)); 2127 2128 cpufreq_cpu_put(cpu_policy); 2129 return 0; 2130 } 2131 EXPORT_SYMBOL(cpufreq_get_policy); 2132 2133 /* 2134 * policy : current policy. 2135 * new_policy: policy to be set. 2136 */ 2137 static int cpufreq_set_policy(struct cpufreq_policy *policy, 2138 struct cpufreq_policy *new_policy) 2139 { 2140 struct cpufreq_governor *old_gov; 2141 int ret; 2142 2143 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", 2144 new_policy->cpu, new_policy->min, new_policy->max); 2145 2146 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); 2147 2148 if (new_policy->min > policy->max || new_policy->max < policy->min) 2149 return -EINVAL; 2150 2151 /* verify the cpu speed can be set within this limit */ 2152 ret = cpufreq_driver->verify(new_policy); 2153 if (ret) 2154 return ret; 2155 2156 /* adjust if necessary - all reasons */ 2157 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2158 CPUFREQ_ADJUST, new_policy); 2159 2160 /* adjust if necessary - hardware incompatibility*/ 2161 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2162 CPUFREQ_INCOMPATIBLE, new_policy); 2163 2164 /* 2165 * verify the cpu speed can be set within this limit, which might be 2166 * different to the first one 2167 */ 2168 ret = cpufreq_driver->verify(new_policy); 2169 if (ret) 2170 return ret; 2171 2172 /* notification of the new policy */ 2173 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2174 CPUFREQ_NOTIFY, new_policy); 2175 2176 policy->min = new_policy->min; 2177 policy->max = new_policy->max; 2178 2179 pr_debug("new min and max freqs are %u - %u kHz\n", 2180 policy->min, policy->max); 2181 2182 if (cpufreq_driver->setpolicy) { 2183 policy->policy = new_policy->policy; 2184 pr_debug("setting range\n"); 2185 return cpufreq_driver->setpolicy(new_policy); 2186 } 2187 2188 if (new_policy->governor == policy->governor) 2189 goto out; 2190 2191 pr_debug("governor switch\n"); 2192 2193 /* save old, working values */ 2194 old_gov = policy->governor; 2195 /* end old governor */ 2196 if (old_gov) { 2197 __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 2198 up_write(&policy->rwsem); 2199 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2200 down_write(&policy->rwsem); 2201 } 2202 2203 /* start new governor */ 2204 policy->governor = new_policy->governor; 2205 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { 2206 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) 2207 goto out; 2208 2209 up_write(&policy->rwsem); 2210 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2211 down_write(&policy->rwsem); 2212 } 2213 2214 /* new governor failed, so re-start old one */ 2215 pr_debug("starting governor %s failed\n", policy->governor->name); 2216 if (old_gov) { 2217 policy->governor = old_gov; 2218 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); 2219 __cpufreq_governor(policy, CPUFREQ_GOV_START); 2220 } 2221 2222 return -EINVAL; 2223 2224 out: 2225 pr_debug("governor: change or update limits\n"); 2226 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2227 } 2228 2229 /** 2230 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 2231 * @cpu: CPU which shall be re-evaluated 2232 * 2233 * Useful for policy notifiers which have different necessities 2234 * at different times. 2235 */ 2236 int cpufreq_update_policy(unsigned int cpu) 2237 { 2238 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 2239 struct cpufreq_policy new_policy; 2240 int ret; 2241 2242 if (!policy) 2243 return -ENODEV; 2244 2245 down_write(&policy->rwsem); 2246 2247 pr_debug("updating policy for CPU %u\n", cpu); 2248 memcpy(&new_policy, policy, sizeof(*policy)); 2249 new_policy.min = policy->user_policy.min; 2250 new_policy.max = policy->user_policy.max; 2251 new_policy.policy = policy->user_policy.policy; 2252 new_policy.governor = policy->user_policy.governor; 2253 2254 /* 2255 * BIOS might change freq behind our back 2256 * -> ask driver for current freq and notify governors about a change 2257 */ 2258 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 2259 new_policy.cur = cpufreq_driver->get(cpu); 2260 if (WARN_ON(!new_policy.cur)) { 2261 ret = -EIO; 2262 goto unlock; 2263 } 2264 2265 if (!policy->cur) { 2266 pr_debug("Driver did not initialize current freq\n"); 2267 policy->cur = new_policy.cur; 2268 } else { 2269 if (policy->cur != new_policy.cur && has_target()) 2270 cpufreq_out_of_sync(cpu, policy->cur, 2271 new_policy.cur); 2272 } 2273 } 2274 2275 ret = cpufreq_set_policy(policy, &new_policy); 2276 2277 unlock: 2278 up_write(&policy->rwsem); 2279 2280 cpufreq_cpu_put(policy); 2281 return ret; 2282 } 2283 EXPORT_SYMBOL(cpufreq_update_policy); 2284 2285 static int cpufreq_cpu_callback(struct notifier_block *nfb, 2286 unsigned long action, void *hcpu) 2287 { 2288 unsigned int cpu = (unsigned long)hcpu; 2289 struct device *dev; 2290 2291 dev = get_cpu_device(cpu); 2292 if (dev) { 2293 switch (action & ~CPU_TASKS_FROZEN) { 2294 case CPU_ONLINE: 2295 __cpufreq_add_dev(dev, NULL); 2296 break; 2297 2298 case CPU_DOWN_PREPARE: 2299 __cpufreq_remove_dev_prepare(dev, NULL); 2300 break; 2301 2302 case CPU_POST_DEAD: 2303 __cpufreq_remove_dev_finish(dev, NULL); 2304 break; 2305 2306 case CPU_DOWN_FAILED: 2307 __cpufreq_add_dev(dev, NULL); 2308 break; 2309 } 2310 } 2311 return NOTIFY_OK; 2312 } 2313 2314 static struct notifier_block __refdata cpufreq_cpu_notifier = { 2315 .notifier_call = cpufreq_cpu_callback, 2316 }; 2317 2318 /********************************************************************* 2319 * BOOST * 2320 *********************************************************************/ 2321 static int cpufreq_boost_set_sw(int state) 2322 { 2323 struct cpufreq_frequency_table *freq_table; 2324 struct cpufreq_policy *policy; 2325 int ret = -EINVAL; 2326 2327 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 2328 freq_table = cpufreq_frequency_get_table(policy->cpu); 2329 if (freq_table) { 2330 ret = cpufreq_frequency_table_cpuinfo(policy, 2331 freq_table); 2332 if (ret) { 2333 pr_err("%s: Policy frequency update failed\n", 2334 __func__); 2335 break; 2336 } 2337 policy->user_policy.max = policy->max; 2338 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2339 } 2340 } 2341 2342 return ret; 2343 } 2344 2345 int cpufreq_boost_trigger_state(int state) 2346 { 2347 unsigned long flags; 2348 int ret = 0; 2349 2350 if (cpufreq_driver->boost_enabled == state) 2351 return 0; 2352 2353 write_lock_irqsave(&cpufreq_driver_lock, flags); 2354 cpufreq_driver->boost_enabled = state; 2355 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2356 2357 ret = cpufreq_driver->set_boost(state); 2358 if (ret) { 2359 write_lock_irqsave(&cpufreq_driver_lock, flags); 2360 cpufreq_driver->boost_enabled = !state; 2361 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2362 2363 pr_err("%s: Cannot %s BOOST\n", 2364 __func__, state ? "enable" : "disable"); 2365 } 2366 2367 return ret; 2368 } 2369 2370 int cpufreq_boost_supported(void) 2371 { 2372 if (likely(cpufreq_driver)) 2373 return cpufreq_driver->boost_supported; 2374 2375 return 0; 2376 } 2377 EXPORT_SYMBOL_GPL(cpufreq_boost_supported); 2378 2379 int cpufreq_boost_enabled(void) 2380 { 2381 return cpufreq_driver->boost_enabled; 2382 } 2383 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); 2384 2385 /********************************************************************* 2386 * REGISTER / UNREGISTER CPUFREQ DRIVER * 2387 *********************************************************************/ 2388 2389 /** 2390 * cpufreq_register_driver - register a CPU Frequency driver 2391 * @driver_data: A struct cpufreq_driver containing the values# 2392 * submitted by the CPU Frequency driver. 2393 * 2394 * Registers a CPU Frequency driver to this core code. This code 2395 * returns zero on success, -EBUSY when another driver got here first 2396 * (and isn't unregistered in the meantime). 2397 * 2398 */ 2399 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 2400 { 2401 unsigned long flags; 2402 int ret; 2403 2404 if (cpufreq_disabled()) 2405 return -ENODEV; 2406 2407 if (!driver_data || !driver_data->verify || !driver_data->init || 2408 !(driver_data->setpolicy || driver_data->target_index || 2409 driver_data->target) || 2410 (driver_data->setpolicy && (driver_data->target_index || 2411 driver_data->target)) || 2412 (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) 2413 return -EINVAL; 2414 2415 pr_debug("trying to register driver %s\n", driver_data->name); 2416 2417 if (driver_data->setpolicy) 2418 driver_data->flags |= CPUFREQ_CONST_LOOPS; 2419 2420 write_lock_irqsave(&cpufreq_driver_lock, flags); 2421 if (cpufreq_driver) { 2422 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2423 return -EEXIST; 2424 } 2425 cpufreq_driver = driver_data; 2426 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2427 2428 if (cpufreq_boost_supported()) { 2429 /* 2430 * Check if driver provides function to enable boost - 2431 * if not, use cpufreq_boost_set_sw as default 2432 */ 2433 if (!cpufreq_driver->set_boost) 2434 cpufreq_driver->set_boost = cpufreq_boost_set_sw; 2435 2436 ret = cpufreq_sysfs_create_file(&boost.attr); 2437 if (ret) { 2438 pr_err("%s: cannot register global BOOST sysfs file\n", 2439 __func__); 2440 goto err_null_driver; 2441 } 2442 } 2443 2444 ret = subsys_interface_register(&cpufreq_interface); 2445 if (ret) 2446 goto err_boost_unreg; 2447 2448 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { 2449 int i; 2450 ret = -ENODEV; 2451 2452 /* check for at least one working CPU */ 2453 for (i = 0; i < nr_cpu_ids; i++) 2454 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { 2455 ret = 0; 2456 break; 2457 } 2458 2459 /* if all ->init() calls failed, unregister */ 2460 if (ret) { 2461 pr_debug("no CPU initialized for driver %s\n", 2462 driver_data->name); 2463 goto err_if_unreg; 2464 } 2465 } 2466 2467 register_hotcpu_notifier(&cpufreq_cpu_notifier); 2468 pr_debug("driver %s up and running\n", driver_data->name); 2469 2470 return 0; 2471 err_if_unreg: 2472 subsys_interface_unregister(&cpufreq_interface); 2473 err_boost_unreg: 2474 if (cpufreq_boost_supported()) 2475 cpufreq_sysfs_remove_file(&boost.attr); 2476 err_null_driver: 2477 write_lock_irqsave(&cpufreq_driver_lock, flags); 2478 cpufreq_driver = NULL; 2479 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2480 return ret; 2481 } 2482 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 2483 2484 /** 2485 * cpufreq_unregister_driver - unregister the current CPUFreq driver 2486 * 2487 * Unregister the current CPUFreq driver. Only call this if you have 2488 * the right to do so, i.e. if you have succeeded in initialising before! 2489 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 2490 * currently not initialised. 2491 */ 2492 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 2493 { 2494 unsigned long flags; 2495 2496 if (!cpufreq_driver || (driver != cpufreq_driver)) 2497 return -EINVAL; 2498 2499 pr_debug("unregistering driver %s\n", driver->name); 2500 2501 subsys_interface_unregister(&cpufreq_interface); 2502 if (cpufreq_boost_supported()) 2503 cpufreq_sysfs_remove_file(&boost.attr); 2504 2505 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 2506 2507 down_write(&cpufreq_rwsem); 2508 write_lock_irqsave(&cpufreq_driver_lock, flags); 2509 2510 cpufreq_driver = NULL; 2511 2512 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2513 up_write(&cpufreq_rwsem); 2514 2515 return 0; 2516 } 2517 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 2518 2519 static int __init cpufreq_core_init(void) 2520 { 2521 if (cpufreq_disabled()) 2522 return -ENODEV; 2523 2524 cpufreq_global_kobject = kobject_create(); 2525 BUG_ON(!cpufreq_global_kobject); 2526 2527 return 0; 2528 } 2529 core_initcall(cpufreq_core_init); 2530