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