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 WARN_ON(kobject_move(&policy->kobj, &dev->kobj)); 1159 } else { 1160 policy->cpu = cpu; 1161 } 1162 1163 cpumask_copy(policy->cpus, cpumask_of(cpu)); 1164 1165 init_completion(&policy->kobj_unregister); 1166 INIT_WORK(&policy->update, handle_update); 1167 1168 /* call driver. From then on the cpufreq must be able 1169 * to accept all calls to ->verify and ->setpolicy for this CPU 1170 */ 1171 ret = cpufreq_driver->init(policy); 1172 if (ret) { 1173 pr_debug("initialization failed\n"); 1174 goto err_set_policy_cpu; 1175 } 1176 1177 /* related cpus should atleast have policy->cpus */ 1178 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); 1179 1180 /* 1181 * affected cpus must always be the one, which are online. We aren't 1182 * managing offline cpus here. 1183 */ 1184 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); 1185 1186 if (!recover_policy) { 1187 policy->user_policy.min = policy->min; 1188 policy->user_policy.max = policy->max; 1189 } 1190 1191 down_write(&policy->rwsem); 1192 write_lock_irqsave(&cpufreq_driver_lock, flags); 1193 for_each_cpu(j, policy->cpus) 1194 per_cpu(cpufreq_cpu_data, j) = policy; 1195 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1196 1197 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 1198 policy->cur = cpufreq_driver->get(policy->cpu); 1199 if (!policy->cur) { 1200 pr_err("%s: ->get() failed\n", __func__); 1201 goto err_get_freq; 1202 } 1203 } 1204 1205 /* 1206 * Sometimes boot loaders set CPU frequency to a value outside of 1207 * frequency table present with cpufreq core. In such cases CPU might be 1208 * unstable if it has to run on that frequency for long duration of time 1209 * and so its better to set it to a frequency which is specified in 1210 * freq-table. This also makes cpufreq stats inconsistent as 1211 * cpufreq-stats would fail to register because current frequency of CPU 1212 * isn't found in freq-table. 1213 * 1214 * Because we don't want this change to effect boot process badly, we go 1215 * for the next freq which is >= policy->cur ('cur' must be set by now, 1216 * otherwise we will end up setting freq to lowest of the table as 'cur' 1217 * is initialized to zero). 1218 * 1219 * We are passing target-freq as "policy->cur - 1" otherwise 1220 * __cpufreq_driver_target() would simply fail, as policy->cur will be 1221 * equal to target-freq. 1222 */ 1223 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) 1224 && has_target()) { 1225 /* Are we running at unknown frequency ? */ 1226 ret = cpufreq_frequency_table_get_index(policy, policy->cur); 1227 if (ret == -EINVAL) { 1228 /* Warn user and fix it */ 1229 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", 1230 __func__, policy->cpu, policy->cur); 1231 ret = __cpufreq_driver_target(policy, policy->cur - 1, 1232 CPUFREQ_RELATION_L); 1233 1234 /* 1235 * Reaching here after boot in a few seconds may not 1236 * mean that system will remain stable at "unknown" 1237 * frequency for longer duration. Hence, a BUG_ON(). 1238 */ 1239 BUG_ON(ret); 1240 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", 1241 __func__, policy->cpu, policy->cur); 1242 } 1243 } 1244 1245 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1246 CPUFREQ_START, policy); 1247 1248 if (!recover_policy) { 1249 ret = cpufreq_add_dev_interface(policy, dev); 1250 if (ret) 1251 goto err_out_unregister; 1252 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1253 CPUFREQ_CREATE_POLICY, policy); 1254 } 1255 1256 write_lock_irqsave(&cpufreq_driver_lock, flags); 1257 list_add(&policy->policy_list, &cpufreq_policy_list); 1258 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1259 1260 cpufreq_init_policy(policy); 1261 1262 if (!recover_policy) { 1263 policy->user_policy.policy = policy->policy; 1264 policy->user_policy.governor = policy->governor; 1265 } 1266 up_write(&policy->rwsem); 1267 1268 kobject_uevent(&policy->kobj, KOBJ_ADD); 1269 up_read(&cpufreq_rwsem); 1270 1271 pr_debug("initialization complete\n"); 1272 1273 return 0; 1274 1275 err_out_unregister: 1276 err_get_freq: 1277 write_lock_irqsave(&cpufreq_driver_lock, flags); 1278 for_each_cpu(j, policy->cpus) 1279 per_cpu(cpufreq_cpu_data, j) = NULL; 1280 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1281 1282 if (cpufreq_driver->exit) 1283 cpufreq_driver->exit(policy); 1284 err_set_policy_cpu: 1285 if (recover_policy) { 1286 /* Do not leave stale fallback data behind. */ 1287 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL; 1288 cpufreq_policy_put_kobj(policy); 1289 } 1290 cpufreq_policy_free(policy); 1291 1292 nomem_out: 1293 up_read(&cpufreq_rwsem); 1294 1295 return ret; 1296 } 1297 1298 /** 1299 * cpufreq_add_dev - add a CPU device 1300 * 1301 * Adds the cpufreq interface for a CPU device. 1302 * 1303 * The Oracle says: try running cpufreq registration/unregistration concurrently 1304 * with with cpu hotplugging and all hell will break loose. Tried to clean this 1305 * mess up, but more thorough testing is needed. - Mathieu 1306 */ 1307 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1308 { 1309 return __cpufreq_add_dev(dev, sif); 1310 } 1311 1312 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, 1313 unsigned int old_cpu) 1314 { 1315 struct device *cpu_dev; 1316 int ret; 1317 1318 /* first sibling now owns the new sysfs dir */ 1319 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu)); 1320 1321 sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); 1322 ret = kobject_move(&policy->kobj, &cpu_dev->kobj); 1323 if (ret) { 1324 pr_err("%s: Failed to move kobj: %d\n", __func__, ret); 1325 1326 down_write(&policy->rwsem); 1327 cpumask_set_cpu(old_cpu, policy->cpus); 1328 up_write(&policy->rwsem); 1329 1330 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, 1331 "cpufreq"); 1332 1333 return -EINVAL; 1334 } 1335 1336 return cpu_dev->id; 1337 } 1338 1339 static int __cpufreq_remove_dev_prepare(struct device *dev, 1340 struct subsys_interface *sif) 1341 { 1342 unsigned int cpu = dev->id, cpus; 1343 int new_cpu, ret; 1344 unsigned long flags; 1345 struct cpufreq_policy *policy; 1346 1347 pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 1348 1349 write_lock_irqsave(&cpufreq_driver_lock, flags); 1350 1351 policy = per_cpu(cpufreq_cpu_data, cpu); 1352 1353 /* Save the policy somewhere when doing a light-weight tear-down */ 1354 if (cpufreq_suspended) 1355 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy; 1356 1357 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1358 1359 if (!policy) { 1360 pr_debug("%s: No cpu_data found\n", __func__); 1361 return -EINVAL; 1362 } 1363 1364 if (has_target()) { 1365 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 1366 if (ret) { 1367 pr_err("%s: Failed to stop governor\n", __func__); 1368 return ret; 1369 } 1370 } 1371 1372 if (!cpufreq_driver->setpolicy) 1373 strncpy(per_cpu(cpufreq_cpu_governor, cpu), 1374 policy->governor->name, CPUFREQ_NAME_LEN); 1375 1376 down_read(&policy->rwsem); 1377 cpus = cpumask_weight(policy->cpus); 1378 up_read(&policy->rwsem); 1379 1380 if (cpu != policy->cpu) { 1381 sysfs_remove_link(&dev->kobj, "cpufreq"); 1382 } else if (cpus > 1) { 1383 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu); 1384 if (new_cpu >= 0) { 1385 update_policy_cpu(policy, new_cpu); 1386 1387 if (!cpufreq_suspended) 1388 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", 1389 __func__, new_cpu, cpu); 1390 } 1391 } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) { 1392 cpufreq_driver->stop_cpu(policy); 1393 } 1394 1395 return 0; 1396 } 1397 1398 static int __cpufreq_remove_dev_finish(struct device *dev, 1399 struct subsys_interface *sif) 1400 { 1401 unsigned int cpu = dev->id, cpus; 1402 int ret; 1403 unsigned long flags; 1404 struct cpufreq_policy *policy; 1405 1406 read_lock_irqsave(&cpufreq_driver_lock, flags); 1407 policy = per_cpu(cpufreq_cpu_data, cpu); 1408 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1409 1410 if (!policy) { 1411 pr_debug("%s: No cpu_data found\n", __func__); 1412 return -EINVAL; 1413 } 1414 1415 down_write(&policy->rwsem); 1416 cpus = cpumask_weight(policy->cpus); 1417 1418 if (cpus > 1) 1419 cpumask_clear_cpu(cpu, policy->cpus); 1420 up_write(&policy->rwsem); 1421 1422 /* If cpu is last user of policy, free policy */ 1423 if (cpus == 1) { 1424 if (has_target()) { 1425 ret = __cpufreq_governor(policy, 1426 CPUFREQ_GOV_POLICY_EXIT); 1427 if (ret) { 1428 pr_err("%s: Failed to exit governor\n", 1429 __func__); 1430 return ret; 1431 } 1432 } 1433 1434 if (!cpufreq_suspended) 1435 cpufreq_policy_put_kobj(policy); 1436 1437 /* 1438 * Perform the ->exit() even during light-weight tear-down, 1439 * since this is a core component, and is essential for the 1440 * subsequent light-weight ->init() to succeed. 1441 */ 1442 if (cpufreq_driver->exit) 1443 cpufreq_driver->exit(policy); 1444 1445 /* Remove policy from list of active policies */ 1446 write_lock_irqsave(&cpufreq_driver_lock, flags); 1447 list_del(&policy->policy_list); 1448 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1449 1450 if (!cpufreq_suspended) 1451 cpufreq_policy_free(policy); 1452 } else if (has_target()) { 1453 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); 1454 if (!ret) 1455 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 1456 1457 if (ret) { 1458 pr_err("%s: Failed to start governor\n", __func__); 1459 return ret; 1460 } 1461 } 1462 1463 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1464 return 0; 1465 } 1466 1467 /** 1468 * cpufreq_remove_dev - remove a CPU device 1469 * 1470 * Removes the cpufreq interface for a CPU device. 1471 */ 1472 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 1473 { 1474 unsigned int cpu = dev->id; 1475 int ret; 1476 1477 if (cpu_is_offline(cpu)) 1478 return 0; 1479 1480 ret = __cpufreq_remove_dev_prepare(dev, sif); 1481 1482 if (!ret) 1483 ret = __cpufreq_remove_dev_finish(dev, sif); 1484 1485 return ret; 1486 } 1487 1488 static void handle_update(struct work_struct *work) 1489 { 1490 struct cpufreq_policy *policy = 1491 container_of(work, struct cpufreq_policy, update); 1492 unsigned int cpu = policy->cpu; 1493 pr_debug("handle_update for cpu %u called\n", cpu); 1494 cpufreq_update_policy(cpu); 1495 } 1496 1497 /** 1498 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're 1499 * in deep trouble. 1500 * @cpu: cpu number 1501 * @old_freq: CPU frequency the kernel thinks the CPU runs at 1502 * @new_freq: CPU frequency the CPU actually runs at 1503 * 1504 * We adjust to current frequency first, and need to clean up later. 1505 * So either call to cpufreq_update_policy() or schedule handle_update()). 1506 */ 1507 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, 1508 unsigned int new_freq) 1509 { 1510 struct cpufreq_policy *policy; 1511 struct cpufreq_freqs freqs; 1512 unsigned long flags; 1513 1514 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n", 1515 old_freq, new_freq); 1516 1517 freqs.old = old_freq; 1518 freqs.new = new_freq; 1519 1520 read_lock_irqsave(&cpufreq_driver_lock, flags); 1521 policy = per_cpu(cpufreq_cpu_data, cpu); 1522 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1523 1524 cpufreq_freq_transition_begin(policy, &freqs); 1525 cpufreq_freq_transition_end(policy, &freqs, 0); 1526 } 1527 1528 /** 1529 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1530 * @cpu: CPU number 1531 * 1532 * This is the last known freq, without actually getting it from the driver. 1533 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1534 */ 1535 unsigned int cpufreq_quick_get(unsigned int cpu) 1536 { 1537 struct cpufreq_policy *policy; 1538 unsigned int ret_freq = 0; 1539 1540 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) 1541 return cpufreq_driver->get(cpu); 1542 1543 policy = cpufreq_cpu_get(cpu); 1544 if (policy) { 1545 ret_freq = policy->cur; 1546 cpufreq_cpu_put(policy); 1547 } 1548 1549 return ret_freq; 1550 } 1551 EXPORT_SYMBOL(cpufreq_quick_get); 1552 1553 /** 1554 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU 1555 * @cpu: CPU number 1556 * 1557 * Just return the max possible frequency for a given CPU. 1558 */ 1559 unsigned int cpufreq_quick_get_max(unsigned int cpu) 1560 { 1561 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1562 unsigned int ret_freq = 0; 1563 1564 if (policy) { 1565 ret_freq = policy->max; 1566 cpufreq_cpu_put(policy); 1567 } 1568 1569 return ret_freq; 1570 } 1571 EXPORT_SYMBOL(cpufreq_quick_get_max); 1572 1573 static unsigned int __cpufreq_get(unsigned int cpu) 1574 { 1575 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1576 unsigned int ret_freq = 0; 1577 1578 if (!cpufreq_driver->get) 1579 return ret_freq; 1580 1581 ret_freq = cpufreq_driver->get(cpu); 1582 1583 if (ret_freq && policy->cur && 1584 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1585 /* verify no discrepancy between actual and 1586 saved value exists */ 1587 if (unlikely(ret_freq != policy->cur)) { 1588 cpufreq_out_of_sync(cpu, policy->cur, ret_freq); 1589 schedule_work(&policy->update); 1590 } 1591 } 1592 1593 return ret_freq; 1594 } 1595 1596 /** 1597 * cpufreq_get - get the current CPU frequency (in kHz) 1598 * @cpu: CPU number 1599 * 1600 * Get the CPU current (static) CPU frequency 1601 */ 1602 unsigned int cpufreq_get(unsigned int cpu) 1603 { 1604 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1605 unsigned int ret_freq = 0; 1606 1607 if (policy) { 1608 down_read(&policy->rwsem); 1609 ret_freq = __cpufreq_get(cpu); 1610 up_read(&policy->rwsem); 1611 1612 cpufreq_cpu_put(policy); 1613 } 1614 1615 return ret_freq; 1616 } 1617 EXPORT_SYMBOL(cpufreq_get); 1618 1619 static struct subsys_interface cpufreq_interface = { 1620 .name = "cpufreq", 1621 .subsys = &cpu_subsys, 1622 .add_dev = cpufreq_add_dev, 1623 .remove_dev = cpufreq_remove_dev, 1624 }; 1625 1626 /* 1627 * In case platform wants some specific frequency to be configured 1628 * during suspend.. 1629 */ 1630 int cpufreq_generic_suspend(struct cpufreq_policy *policy) 1631 { 1632 int ret; 1633 1634 if (!policy->suspend_freq) { 1635 pr_err("%s: suspend_freq can't be zero\n", __func__); 1636 return -EINVAL; 1637 } 1638 1639 pr_debug("%s: Setting suspend-freq: %u\n", __func__, 1640 policy->suspend_freq); 1641 1642 ret = __cpufreq_driver_target(policy, policy->suspend_freq, 1643 CPUFREQ_RELATION_H); 1644 if (ret) 1645 pr_err("%s: unable to set suspend-freq: %u. err: %d\n", 1646 __func__, policy->suspend_freq, ret); 1647 1648 return ret; 1649 } 1650 EXPORT_SYMBOL(cpufreq_generic_suspend); 1651 1652 /** 1653 * cpufreq_suspend() - Suspend CPUFreq governors 1654 * 1655 * Called during system wide Suspend/Hibernate cycles for suspending governors 1656 * as some platforms can't change frequency after this point in suspend cycle. 1657 * Because some of the devices (like: i2c, regulators, etc) they use for 1658 * changing frequency are suspended quickly after this point. 1659 */ 1660 void cpufreq_suspend(void) 1661 { 1662 struct cpufreq_policy *policy; 1663 1664 if (!cpufreq_driver) 1665 return; 1666 1667 if (!has_target()) 1668 return; 1669 1670 pr_debug("%s: Suspending Governors\n", __func__); 1671 1672 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1673 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP)) 1674 pr_err("%s: Failed to stop governor for policy: %p\n", 1675 __func__, policy); 1676 else if (cpufreq_driver->suspend 1677 && cpufreq_driver->suspend(policy)) 1678 pr_err("%s: Failed to suspend driver: %p\n", __func__, 1679 policy); 1680 } 1681 1682 cpufreq_suspended = true; 1683 } 1684 1685 /** 1686 * cpufreq_resume() - Resume CPUFreq governors 1687 * 1688 * Called during system wide Suspend/Hibernate cycle for resuming governors that 1689 * are suspended with cpufreq_suspend(). 1690 */ 1691 void cpufreq_resume(void) 1692 { 1693 struct cpufreq_policy *policy; 1694 1695 if (!cpufreq_driver) 1696 return; 1697 1698 if (!has_target()) 1699 return; 1700 1701 pr_debug("%s: Resuming Governors\n", __func__); 1702 1703 cpufreq_suspended = false; 1704 1705 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 1706 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) 1707 pr_err("%s: Failed to resume driver: %p\n", __func__, 1708 policy); 1709 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START) 1710 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS)) 1711 pr_err("%s: Failed to start governor for policy: %p\n", 1712 __func__, policy); 1713 1714 /* 1715 * schedule call cpufreq_update_policy() for boot CPU, i.e. last 1716 * policy in list. It will verify that the current freq is in 1717 * sync with what we believe it to be. 1718 */ 1719 if (list_is_last(&policy->policy_list, &cpufreq_policy_list)) 1720 schedule_work(&policy->update); 1721 } 1722 } 1723 1724 /** 1725 * cpufreq_get_current_driver - return current driver's name 1726 * 1727 * Return the name string of the currently loaded cpufreq driver 1728 * or NULL, if none. 1729 */ 1730 const char *cpufreq_get_current_driver(void) 1731 { 1732 if (cpufreq_driver) 1733 return cpufreq_driver->name; 1734 1735 return NULL; 1736 } 1737 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); 1738 1739 /********************************************************************* 1740 * NOTIFIER LISTS INTERFACE * 1741 *********************************************************************/ 1742 1743 /** 1744 * cpufreq_register_notifier - register a driver with cpufreq 1745 * @nb: notifier function to register 1746 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1747 * 1748 * Add a driver to one of two lists: either a list of drivers that 1749 * are notified about clock rate changes (once before and once after 1750 * the transition), or a list of drivers that are notified about 1751 * changes in cpufreq policy. 1752 * 1753 * This function may sleep, and has the same return conditions as 1754 * blocking_notifier_chain_register. 1755 */ 1756 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1757 { 1758 int ret; 1759 1760 if (cpufreq_disabled()) 1761 return -EINVAL; 1762 1763 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1764 1765 switch (list) { 1766 case CPUFREQ_TRANSITION_NOTIFIER: 1767 ret = srcu_notifier_chain_register( 1768 &cpufreq_transition_notifier_list, nb); 1769 break; 1770 case CPUFREQ_POLICY_NOTIFIER: 1771 ret = blocking_notifier_chain_register( 1772 &cpufreq_policy_notifier_list, nb); 1773 break; 1774 default: 1775 ret = -EINVAL; 1776 } 1777 1778 return ret; 1779 } 1780 EXPORT_SYMBOL(cpufreq_register_notifier); 1781 1782 /** 1783 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1784 * @nb: notifier block to be unregistered 1785 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1786 * 1787 * Remove a driver from the CPU frequency notifier list. 1788 * 1789 * This function may sleep, and has the same return conditions as 1790 * blocking_notifier_chain_unregister. 1791 */ 1792 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1793 { 1794 int ret; 1795 1796 if (cpufreq_disabled()) 1797 return -EINVAL; 1798 1799 switch (list) { 1800 case CPUFREQ_TRANSITION_NOTIFIER: 1801 ret = srcu_notifier_chain_unregister( 1802 &cpufreq_transition_notifier_list, nb); 1803 break; 1804 case CPUFREQ_POLICY_NOTIFIER: 1805 ret = blocking_notifier_chain_unregister( 1806 &cpufreq_policy_notifier_list, nb); 1807 break; 1808 default: 1809 ret = -EINVAL; 1810 } 1811 1812 return ret; 1813 } 1814 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1815 1816 1817 /********************************************************************* 1818 * GOVERNORS * 1819 *********************************************************************/ 1820 1821 /* Must set freqs->new to intermediate frequency */ 1822 static int __target_intermediate(struct cpufreq_policy *policy, 1823 struct cpufreq_freqs *freqs, int index) 1824 { 1825 int ret; 1826 1827 freqs->new = cpufreq_driver->get_intermediate(policy, index); 1828 1829 /* We don't need to switch to intermediate freq */ 1830 if (!freqs->new) 1831 return 0; 1832 1833 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", 1834 __func__, policy->cpu, freqs->old, freqs->new); 1835 1836 cpufreq_freq_transition_begin(policy, freqs); 1837 ret = cpufreq_driver->target_intermediate(policy, index); 1838 cpufreq_freq_transition_end(policy, freqs, ret); 1839 1840 if (ret) 1841 pr_err("%s: Failed to change to intermediate frequency: %d\n", 1842 __func__, ret); 1843 1844 return ret; 1845 } 1846 1847 static int __target_index(struct cpufreq_policy *policy, 1848 struct cpufreq_frequency_table *freq_table, int index) 1849 { 1850 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; 1851 unsigned int intermediate_freq = 0; 1852 int retval = -EINVAL; 1853 bool notify; 1854 1855 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); 1856 if (notify) { 1857 /* Handle switching to intermediate frequency */ 1858 if (cpufreq_driver->get_intermediate) { 1859 retval = __target_intermediate(policy, &freqs, index); 1860 if (retval) 1861 return retval; 1862 1863 intermediate_freq = freqs.new; 1864 /* Set old freq to intermediate */ 1865 if (intermediate_freq) 1866 freqs.old = freqs.new; 1867 } 1868 1869 freqs.new = freq_table[index].frequency; 1870 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", 1871 __func__, policy->cpu, freqs.old, freqs.new); 1872 1873 cpufreq_freq_transition_begin(policy, &freqs); 1874 } 1875 1876 retval = cpufreq_driver->target_index(policy, index); 1877 if (retval) 1878 pr_err("%s: Failed to change cpu frequency: %d\n", __func__, 1879 retval); 1880 1881 if (notify) { 1882 cpufreq_freq_transition_end(policy, &freqs, retval); 1883 1884 /* 1885 * Failed after setting to intermediate freq? Driver should have 1886 * reverted back to initial frequency and so should we. Check 1887 * here for intermediate_freq instead of get_intermediate, in 1888 * case we have't switched to intermediate freq at all. 1889 */ 1890 if (unlikely(retval && intermediate_freq)) { 1891 freqs.old = intermediate_freq; 1892 freqs.new = policy->restore_freq; 1893 cpufreq_freq_transition_begin(policy, &freqs); 1894 cpufreq_freq_transition_end(policy, &freqs, 0); 1895 } 1896 } 1897 1898 return retval; 1899 } 1900 1901 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1902 unsigned int target_freq, 1903 unsigned int relation) 1904 { 1905 unsigned int old_target_freq = target_freq; 1906 int retval = -EINVAL; 1907 1908 if (cpufreq_disabled()) 1909 return -ENODEV; 1910 1911 /* Make sure that target_freq is within supported range */ 1912 if (target_freq > policy->max) 1913 target_freq = policy->max; 1914 if (target_freq < policy->min) 1915 target_freq = policy->min; 1916 1917 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", 1918 policy->cpu, target_freq, relation, old_target_freq); 1919 1920 /* 1921 * This might look like a redundant call as we are checking it again 1922 * after finding index. But it is left intentionally for cases where 1923 * exactly same freq is called again and so we can save on few function 1924 * calls. 1925 */ 1926 if (target_freq == policy->cur) 1927 return 0; 1928 1929 /* Save last value to restore later on errors */ 1930 policy->restore_freq = policy->cur; 1931 1932 if (cpufreq_driver->target) 1933 retval = cpufreq_driver->target(policy, target_freq, relation); 1934 else if (cpufreq_driver->target_index) { 1935 struct cpufreq_frequency_table *freq_table; 1936 int index; 1937 1938 freq_table = cpufreq_frequency_get_table(policy->cpu); 1939 if (unlikely(!freq_table)) { 1940 pr_err("%s: Unable to find freq_table\n", __func__); 1941 goto out; 1942 } 1943 1944 retval = cpufreq_frequency_table_target(policy, freq_table, 1945 target_freq, relation, &index); 1946 if (unlikely(retval)) { 1947 pr_err("%s: Unable to find matching freq\n", __func__); 1948 goto out; 1949 } 1950 1951 if (freq_table[index].frequency == policy->cur) { 1952 retval = 0; 1953 goto out; 1954 } 1955 1956 retval = __target_index(policy, freq_table, index); 1957 } 1958 1959 out: 1960 return retval; 1961 } 1962 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1963 1964 int cpufreq_driver_target(struct cpufreq_policy *policy, 1965 unsigned int target_freq, 1966 unsigned int relation) 1967 { 1968 int ret = -EINVAL; 1969 1970 down_write(&policy->rwsem); 1971 1972 ret = __cpufreq_driver_target(policy, target_freq, relation); 1973 1974 up_write(&policy->rwsem); 1975 1976 return ret; 1977 } 1978 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1979 1980 /* 1981 * when "event" is CPUFREQ_GOV_LIMITS 1982 */ 1983 1984 static int __cpufreq_governor(struct cpufreq_policy *policy, 1985 unsigned int event) 1986 { 1987 int ret; 1988 1989 /* Only must be defined when default governor is known to have latency 1990 restrictions, like e.g. conservative or ondemand. 1991 That this is the case is already ensured in Kconfig 1992 */ 1993 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE 1994 struct cpufreq_governor *gov = &cpufreq_gov_performance; 1995 #else 1996 struct cpufreq_governor *gov = NULL; 1997 #endif 1998 1999 /* Don't start any governor operations if we are entering suspend */ 2000 if (cpufreq_suspended) 2001 return 0; 2002 2003 if (policy->governor->max_transition_latency && 2004 policy->cpuinfo.transition_latency > 2005 policy->governor->max_transition_latency) { 2006 if (!gov) 2007 return -EINVAL; 2008 else { 2009 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", 2010 policy->governor->name, gov->name); 2011 policy->governor = gov; 2012 } 2013 } 2014 2015 if (event == CPUFREQ_GOV_POLICY_INIT) 2016 if (!try_module_get(policy->governor->owner)) 2017 return -EINVAL; 2018 2019 pr_debug("__cpufreq_governor for CPU %u, event %u\n", 2020 policy->cpu, event); 2021 2022 mutex_lock(&cpufreq_governor_lock); 2023 if ((policy->governor_enabled && event == CPUFREQ_GOV_START) 2024 || (!policy->governor_enabled 2025 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { 2026 mutex_unlock(&cpufreq_governor_lock); 2027 return -EBUSY; 2028 } 2029 2030 if (event == CPUFREQ_GOV_STOP) 2031 policy->governor_enabled = false; 2032 else if (event == CPUFREQ_GOV_START) 2033 policy->governor_enabled = true; 2034 2035 mutex_unlock(&cpufreq_governor_lock); 2036 2037 ret = policy->governor->governor(policy, event); 2038 2039 if (!ret) { 2040 if (event == CPUFREQ_GOV_POLICY_INIT) 2041 policy->governor->initialized++; 2042 else if (event == CPUFREQ_GOV_POLICY_EXIT) 2043 policy->governor->initialized--; 2044 } else { 2045 /* Restore original values */ 2046 mutex_lock(&cpufreq_governor_lock); 2047 if (event == CPUFREQ_GOV_STOP) 2048 policy->governor_enabled = true; 2049 else if (event == CPUFREQ_GOV_START) 2050 policy->governor_enabled = false; 2051 mutex_unlock(&cpufreq_governor_lock); 2052 } 2053 2054 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || 2055 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) 2056 module_put(policy->governor->owner); 2057 2058 return ret; 2059 } 2060 2061 int cpufreq_register_governor(struct cpufreq_governor *governor) 2062 { 2063 int err; 2064 2065 if (!governor) 2066 return -EINVAL; 2067 2068 if (cpufreq_disabled()) 2069 return -ENODEV; 2070 2071 mutex_lock(&cpufreq_governor_mutex); 2072 2073 governor->initialized = 0; 2074 err = -EBUSY; 2075 if (__find_governor(governor->name) == NULL) { 2076 err = 0; 2077 list_add(&governor->governor_list, &cpufreq_governor_list); 2078 } 2079 2080 mutex_unlock(&cpufreq_governor_mutex); 2081 return err; 2082 } 2083 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 2084 2085 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 2086 { 2087 int cpu; 2088 2089 if (!governor) 2090 return; 2091 2092 if (cpufreq_disabled()) 2093 return; 2094 2095 for_each_present_cpu(cpu) { 2096 if (cpu_online(cpu)) 2097 continue; 2098 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name)) 2099 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0"); 2100 } 2101 2102 mutex_lock(&cpufreq_governor_mutex); 2103 list_del(&governor->governor_list); 2104 mutex_unlock(&cpufreq_governor_mutex); 2105 return; 2106 } 2107 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 2108 2109 2110 /********************************************************************* 2111 * POLICY INTERFACE * 2112 *********************************************************************/ 2113 2114 /** 2115 * cpufreq_get_policy - get the current cpufreq_policy 2116 * @policy: struct cpufreq_policy into which the current cpufreq_policy 2117 * is written 2118 * 2119 * Reads the current cpufreq policy. 2120 */ 2121 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 2122 { 2123 struct cpufreq_policy *cpu_policy; 2124 if (!policy) 2125 return -EINVAL; 2126 2127 cpu_policy = cpufreq_cpu_get(cpu); 2128 if (!cpu_policy) 2129 return -EINVAL; 2130 2131 memcpy(policy, cpu_policy, sizeof(*policy)); 2132 2133 cpufreq_cpu_put(cpu_policy); 2134 return 0; 2135 } 2136 EXPORT_SYMBOL(cpufreq_get_policy); 2137 2138 /* 2139 * policy : current policy. 2140 * new_policy: policy to be set. 2141 */ 2142 static int cpufreq_set_policy(struct cpufreq_policy *policy, 2143 struct cpufreq_policy *new_policy) 2144 { 2145 struct cpufreq_governor *old_gov; 2146 int ret; 2147 2148 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", 2149 new_policy->cpu, new_policy->min, new_policy->max); 2150 2151 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); 2152 2153 if (new_policy->min > policy->max || new_policy->max < policy->min) 2154 return -EINVAL; 2155 2156 /* verify the cpu speed can be set within this limit */ 2157 ret = cpufreq_driver->verify(new_policy); 2158 if (ret) 2159 return ret; 2160 2161 /* adjust if necessary - all reasons */ 2162 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2163 CPUFREQ_ADJUST, new_policy); 2164 2165 /* adjust if necessary - hardware incompatibility*/ 2166 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2167 CPUFREQ_INCOMPATIBLE, new_policy); 2168 2169 /* 2170 * verify the cpu speed can be set within this limit, which might be 2171 * different to the first one 2172 */ 2173 ret = cpufreq_driver->verify(new_policy); 2174 if (ret) 2175 return ret; 2176 2177 /* notification of the new policy */ 2178 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2179 CPUFREQ_NOTIFY, new_policy); 2180 2181 policy->min = new_policy->min; 2182 policy->max = new_policy->max; 2183 2184 pr_debug("new min and max freqs are %u - %u kHz\n", 2185 policy->min, policy->max); 2186 2187 if (cpufreq_driver->setpolicy) { 2188 policy->policy = new_policy->policy; 2189 pr_debug("setting range\n"); 2190 return cpufreq_driver->setpolicy(new_policy); 2191 } 2192 2193 if (new_policy->governor == policy->governor) 2194 goto out; 2195 2196 pr_debug("governor switch\n"); 2197 2198 /* save old, working values */ 2199 old_gov = policy->governor; 2200 /* end old governor */ 2201 if (old_gov) { 2202 __cpufreq_governor(policy, CPUFREQ_GOV_STOP); 2203 up_write(&policy->rwsem); 2204 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2205 down_write(&policy->rwsem); 2206 } 2207 2208 /* start new governor */ 2209 policy->governor = new_policy->governor; 2210 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { 2211 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) 2212 goto out; 2213 2214 up_write(&policy->rwsem); 2215 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2216 down_write(&policy->rwsem); 2217 } 2218 2219 /* new governor failed, so re-start old one */ 2220 pr_debug("starting governor %s failed\n", policy->governor->name); 2221 if (old_gov) { 2222 policy->governor = old_gov; 2223 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); 2224 __cpufreq_governor(policy, CPUFREQ_GOV_START); 2225 } 2226 2227 return -EINVAL; 2228 2229 out: 2230 pr_debug("governor: change or update limits\n"); 2231 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2232 } 2233 2234 /** 2235 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 2236 * @cpu: CPU which shall be re-evaluated 2237 * 2238 * Useful for policy notifiers which have different necessities 2239 * at different times. 2240 */ 2241 int cpufreq_update_policy(unsigned int cpu) 2242 { 2243 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 2244 struct cpufreq_policy new_policy; 2245 int ret; 2246 2247 if (!policy) 2248 return -ENODEV; 2249 2250 down_write(&policy->rwsem); 2251 2252 pr_debug("updating policy for CPU %u\n", cpu); 2253 memcpy(&new_policy, policy, sizeof(*policy)); 2254 new_policy.min = policy->user_policy.min; 2255 new_policy.max = policy->user_policy.max; 2256 new_policy.policy = policy->user_policy.policy; 2257 new_policy.governor = policy->user_policy.governor; 2258 2259 /* 2260 * BIOS might change freq behind our back 2261 * -> ask driver for current freq and notify governors about a change 2262 */ 2263 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 2264 new_policy.cur = cpufreq_driver->get(cpu); 2265 if (WARN_ON(!new_policy.cur)) { 2266 ret = -EIO; 2267 goto unlock; 2268 } 2269 2270 if (!policy->cur) { 2271 pr_debug("Driver did not initialize current freq\n"); 2272 policy->cur = new_policy.cur; 2273 } else { 2274 if (policy->cur != new_policy.cur && has_target()) 2275 cpufreq_out_of_sync(cpu, policy->cur, 2276 new_policy.cur); 2277 } 2278 } 2279 2280 ret = cpufreq_set_policy(policy, &new_policy); 2281 2282 unlock: 2283 up_write(&policy->rwsem); 2284 2285 cpufreq_cpu_put(policy); 2286 return ret; 2287 } 2288 EXPORT_SYMBOL(cpufreq_update_policy); 2289 2290 static int cpufreq_cpu_callback(struct notifier_block *nfb, 2291 unsigned long action, void *hcpu) 2292 { 2293 unsigned int cpu = (unsigned long)hcpu; 2294 struct device *dev; 2295 2296 dev = get_cpu_device(cpu); 2297 if (dev) { 2298 switch (action & ~CPU_TASKS_FROZEN) { 2299 case CPU_ONLINE: 2300 __cpufreq_add_dev(dev, NULL); 2301 break; 2302 2303 case CPU_DOWN_PREPARE: 2304 __cpufreq_remove_dev_prepare(dev, NULL); 2305 break; 2306 2307 case CPU_POST_DEAD: 2308 __cpufreq_remove_dev_finish(dev, NULL); 2309 break; 2310 2311 case CPU_DOWN_FAILED: 2312 __cpufreq_add_dev(dev, NULL); 2313 break; 2314 } 2315 } 2316 return NOTIFY_OK; 2317 } 2318 2319 static struct notifier_block __refdata cpufreq_cpu_notifier = { 2320 .notifier_call = cpufreq_cpu_callback, 2321 }; 2322 2323 /********************************************************************* 2324 * BOOST * 2325 *********************************************************************/ 2326 static int cpufreq_boost_set_sw(int state) 2327 { 2328 struct cpufreq_frequency_table *freq_table; 2329 struct cpufreq_policy *policy; 2330 int ret = -EINVAL; 2331 2332 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) { 2333 freq_table = cpufreq_frequency_get_table(policy->cpu); 2334 if (freq_table) { 2335 ret = cpufreq_frequency_table_cpuinfo(policy, 2336 freq_table); 2337 if (ret) { 2338 pr_err("%s: Policy frequency update failed\n", 2339 __func__); 2340 break; 2341 } 2342 policy->user_policy.max = policy->max; 2343 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2344 } 2345 } 2346 2347 return ret; 2348 } 2349 2350 int cpufreq_boost_trigger_state(int state) 2351 { 2352 unsigned long flags; 2353 int ret = 0; 2354 2355 if (cpufreq_driver->boost_enabled == state) 2356 return 0; 2357 2358 write_lock_irqsave(&cpufreq_driver_lock, flags); 2359 cpufreq_driver->boost_enabled = state; 2360 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2361 2362 ret = cpufreq_driver->set_boost(state); 2363 if (ret) { 2364 write_lock_irqsave(&cpufreq_driver_lock, flags); 2365 cpufreq_driver->boost_enabled = !state; 2366 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2367 2368 pr_err("%s: Cannot %s BOOST\n", 2369 __func__, state ? "enable" : "disable"); 2370 } 2371 2372 return ret; 2373 } 2374 2375 int cpufreq_boost_supported(void) 2376 { 2377 if (likely(cpufreq_driver)) 2378 return cpufreq_driver->boost_supported; 2379 2380 return 0; 2381 } 2382 EXPORT_SYMBOL_GPL(cpufreq_boost_supported); 2383 2384 int cpufreq_boost_enabled(void) 2385 { 2386 return cpufreq_driver->boost_enabled; 2387 } 2388 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); 2389 2390 /********************************************************************* 2391 * REGISTER / UNREGISTER CPUFREQ DRIVER * 2392 *********************************************************************/ 2393 2394 /** 2395 * cpufreq_register_driver - register a CPU Frequency driver 2396 * @driver_data: A struct cpufreq_driver containing the values# 2397 * submitted by the CPU Frequency driver. 2398 * 2399 * Registers a CPU Frequency driver to this core code. This code 2400 * returns zero on success, -EBUSY when another driver got here first 2401 * (and isn't unregistered in the meantime). 2402 * 2403 */ 2404 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 2405 { 2406 unsigned long flags; 2407 int ret; 2408 2409 if (cpufreq_disabled()) 2410 return -ENODEV; 2411 2412 if (!driver_data || !driver_data->verify || !driver_data->init || 2413 !(driver_data->setpolicy || driver_data->target_index || 2414 driver_data->target) || 2415 (driver_data->setpolicy && (driver_data->target_index || 2416 driver_data->target)) || 2417 (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) 2418 return -EINVAL; 2419 2420 pr_debug("trying to register driver %s\n", driver_data->name); 2421 2422 if (driver_data->setpolicy) 2423 driver_data->flags |= CPUFREQ_CONST_LOOPS; 2424 2425 write_lock_irqsave(&cpufreq_driver_lock, flags); 2426 if (cpufreq_driver) { 2427 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2428 return -EEXIST; 2429 } 2430 cpufreq_driver = driver_data; 2431 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2432 2433 if (cpufreq_boost_supported()) { 2434 /* 2435 * Check if driver provides function to enable boost - 2436 * if not, use cpufreq_boost_set_sw as default 2437 */ 2438 if (!cpufreq_driver->set_boost) 2439 cpufreq_driver->set_boost = cpufreq_boost_set_sw; 2440 2441 ret = cpufreq_sysfs_create_file(&boost.attr); 2442 if (ret) { 2443 pr_err("%s: cannot register global BOOST sysfs file\n", 2444 __func__); 2445 goto err_null_driver; 2446 } 2447 } 2448 2449 ret = subsys_interface_register(&cpufreq_interface); 2450 if (ret) 2451 goto err_boost_unreg; 2452 2453 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { 2454 int i; 2455 ret = -ENODEV; 2456 2457 /* check for at least one working CPU */ 2458 for (i = 0; i < nr_cpu_ids; i++) 2459 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { 2460 ret = 0; 2461 break; 2462 } 2463 2464 /* if all ->init() calls failed, unregister */ 2465 if (ret) { 2466 pr_debug("no CPU initialized for driver %s\n", 2467 driver_data->name); 2468 goto err_if_unreg; 2469 } 2470 } 2471 2472 register_hotcpu_notifier(&cpufreq_cpu_notifier); 2473 pr_debug("driver %s up and running\n", driver_data->name); 2474 2475 return 0; 2476 err_if_unreg: 2477 subsys_interface_unregister(&cpufreq_interface); 2478 err_boost_unreg: 2479 if (cpufreq_boost_supported()) 2480 cpufreq_sysfs_remove_file(&boost.attr); 2481 err_null_driver: 2482 write_lock_irqsave(&cpufreq_driver_lock, flags); 2483 cpufreq_driver = NULL; 2484 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2485 return ret; 2486 } 2487 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 2488 2489 /** 2490 * cpufreq_unregister_driver - unregister the current CPUFreq driver 2491 * 2492 * Unregister the current CPUFreq driver. Only call this if you have 2493 * the right to do so, i.e. if you have succeeded in initialising before! 2494 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 2495 * currently not initialised. 2496 */ 2497 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 2498 { 2499 unsigned long flags; 2500 2501 if (!cpufreq_driver || (driver != cpufreq_driver)) 2502 return -EINVAL; 2503 2504 pr_debug("unregistering driver %s\n", driver->name); 2505 2506 subsys_interface_unregister(&cpufreq_interface); 2507 if (cpufreq_boost_supported()) 2508 cpufreq_sysfs_remove_file(&boost.attr); 2509 2510 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 2511 2512 down_write(&cpufreq_rwsem); 2513 write_lock_irqsave(&cpufreq_driver_lock, flags); 2514 2515 cpufreq_driver = NULL; 2516 2517 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2518 up_write(&cpufreq_rwsem); 2519 2520 return 0; 2521 } 2522 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 2523 2524 static int __init cpufreq_core_init(void) 2525 { 2526 if (cpufreq_disabled()) 2527 return -ENODEV; 2528 2529 cpufreq_global_kobject = kobject_create(); 2530 BUG_ON(!cpufreq_global_kobject); 2531 2532 return 0; 2533 } 2534 core_initcall(cpufreq_core_init); 2535