1 /* 2 * linux/drivers/cpufreq/cpufreq.c 3 * 4 * Copyright (C) 2001 Russell King 5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> 6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org> 7 * 8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com> 9 * Added handling for CPU hotplug 10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com> 11 * Fix handling for CPU hotplug -- affected CPUs 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License version 2 as 15 * published by the Free Software Foundation. 16 */ 17 18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 19 20 #include <linux/cpu.h> 21 #include <linux/cpufreq.h> 22 #include <linux/delay.h> 23 #include <linux/device.h> 24 #include <linux/init.h> 25 #include <linux/kernel_stat.h> 26 #include <linux/module.h> 27 #include <linux/mutex.h> 28 #include <linux/slab.h> 29 #include <linux/suspend.h> 30 #include <linux/syscore_ops.h> 31 #include <linux/tick.h> 32 #include <trace/events/power.h> 33 34 static LIST_HEAD(cpufreq_policy_list); 35 36 static inline bool policy_is_inactive(struct cpufreq_policy *policy) 37 { 38 return cpumask_empty(policy->cpus); 39 } 40 41 /* Macros to iterate over CPU policies */ 42 #define for_each_suitable_policy(__policy, __active) \ 43 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \ 44 if ((__active) == !policy_is_inactive(__policy)) 45 46 #define for_each_active_policy(__policy) \ 47 for_each_suitable_policy(__policy, true) 48 #define for_each_inactive_policy(__policy) \ 49 for_each_suitable_policy(__policy, false) 50 51 #define for_each_policy(__policy) \ 52 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) 53 54 /* Iterate over governors */ 55 static LIST_HEAD(cpufreq_governor_list); 56 #define for_each_governor(__governor) \ 57 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list) 58 59 /** 60 * The "cpufreq driver" - the arch- or hardware-dependent low 61 * level driver of CPUFreq support, and its spinlock. This lock 62 * also protects the cpufreq_cpu_data array. 63 */ 64 static struct cpufreq_driver *cpufreq_driver; 65 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); 66 static DEFINE_RWLOCK(cpufreq_driver_lock); 67 68 /* Flag to suspend/resume CPUFreq governors */ 69 static bool cpufreq_suspended; 70 71 static inline bool has_target(void) 72 { 73 return cpufreq_driver->target_index || cpufreq_driver->target; 74 } 75 76 /* internal prototypes */ 77 static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); 78 static unsigned int __cpufreq_get(struct cpufreq_policy *policy); 79 static int cpufreq_start_governor(struct cpufreq_policy *policy); 80 81 /** 82 * Two notifier lists: the "policy" list is involved in the 83 * validation process for a new CPU frequency policy; the 84 * "transition" list for kernel code that needs to handle 85 * changes to devices when the CPU clock speed changes. 86 * The mutex locks both lists. 87 */ 88 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); 89 static struct srcu_notifier_head cpufreq_transition_notifier_list; 90 91 static bool init_cpufreq_transition_notifier_list_called; 92 static int __init init_cpufreq_transition_notifier_list(void) 93 { 94 srcu_init_notifier_head(&cpufreq_transition_notifier_list); 95 init_cpufreq_transition_notifier_list_called = true; 96 return 0; 97 } 98 pure_initcall(init_cpufreq_transition_notifier_list); 99 100 static int off __read_mostly; 101 static int cpufreq_disabled(void) 102 { 103 return off; 104 } 105 void disable_cpufreq(void) 106 { 107 off = 1; 108 } 109 static DEFINE_MUTEX(cpufreq_governor_mutex); 110 111 bool have_governor_per_policy(void) 112 { 113 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY); 114 } 115 EXPORT_SYMBOL_GPL(have_governor_per_policy); 116 117 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) 118 { 119 if (have_governor_per_policy()) 120 return &policy->kobj; 121 else 122 return cpufreq_global_kobject; 123 } 124 EXPORT_SYMBOL_GPL(get_governor_parent_kobj); 125 126 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) 127 { 128 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 129 130 return policy && !policy_is_inactive(policy) ? 131 policy->freq_table : NULL; 132 } 133 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); 134 135 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) 136 { 137 u64 idle_time; 138 u64 cur_wall_time; 139 u64 busy_time; 140 141 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); 142 143 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; 144 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; 145 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; 146 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; 147 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; 148 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 149 150 idle_time = cur_wall_time - busy_time; 151 if (wall) 152 *wall = cputime_to_usecs(cur_wall_time); 153 154 return cputime_to_usecs(idle_time); 155 } 156 157 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) 158 { 159 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); 160 161 if (idle_time == -1ULL) 162 return get_cpu_idle_time_jiffy(cpu, wall); 163 else if (!io_busy) 164 idle_time += get_cpu_iowait_time_us(cpu, wall); 165 166 return idle_time; 167 } 168 EXPORT_SYMBOL_GPL(get_cpu_idle_time); 169 170 /* 171 * This is a generic cpufreq init() routine which can be used by cpufreq 172 * drivers of SMP systems. It will do following: 173 * - validate & show freq table passed 174 * - set policies transition latency 175 * - policy->cpus with all possible CPUs 176 */ 177 int cpufreq_generic_init(struct cpufreq_policy *policy, 178 struct cpufreq_frequency_table *table, 179 unsigned int transition_latency) 180 { 181 int ret; 182 183 ret = cpufreq_table_validate_and_show(policy, table); 184 if (ret) { 185 pr_err("%s: invalid frequency table: %d\n", __func__, ret); 186 return ret; 187 } 188 189 policy->cpuinfo.transition_latency = transition_latency; 190 191 /* 192 * The driver only supports the SMP configuration where all processors 193 * share the clock and voltage and clock. 194 */ 195 cpumask_setall(policy->cpus); 196 197 return 0; 198 } 199 EXPORT_SYMBOL_GPL(cpufreq_generic_init); 200 201 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu) 202 { 203 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 204 205 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL; 206 } 207 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw); 208 209 unsigned int cpufreq_generic_get(unsigned int cpu) 210 { 211 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); 212 213 if (!policy || IS_ERR(policy->clk)) { 214 pr_err("%s: No %s associated to cpu: %d\n", 215 __func__, policy ? "clk" : "policy", cpu); 216 return 0; 217 } 218 219 return clk_get_rate(policy->clk) / 1000; 220 } 221 EXPORT_SYMBOL_GPL(cpufreq_generic_get); 222 223 /** 224 * cpufreq_cpu_get: returns policy for a cpu and marks it busy. 225 * 226 * @cpu: cpu to find policy for. 227 * 228 * This returns policy for 'cpu', returns NULL if it doesn't exist. 229 * It also increments the kobject reference count to mark it busy and so would 230 * require a corresponding call to cpufreq_cpu_put() to decrement it back. 231 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be 232 * freed as that depends on the kobj count. 233 * 234 * Return: A valid policy on success, otherwise NULL on failure. 235 */ 236 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) 237 { 238 struct cpufreq_policy *policy = NULL; 239 unsigned long flags; 240 241 if (WARN_ON(cpu >= nr_cpu_ids)) 242 return NULL; 243 244 /* get the cpufreq driver */ 245 read_lock_irqsave(&cpufreq_driver_lock, flags); 246 247 if (cpufreq_driver) { 248 /* get the CPU */ 249 policy = cpufreq_cpu_get_raw(cpu); 250 if (policy) 251 kobject_get(&policy->kobj); 252 } 253 254 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 255 256 return policy; 257 } 258 EXPORT_SYMBOL_GPL(cpufreq_cpu_get); 259 260 /** 261 * cpufreq_cpu_put: Decrements the usage count of a policy 262 * 263 * @policy: policy earlier returned by cpufreq_cpu_get(). 264 * 265 * This decrements the kobject reference count incremented earlier by calling 266 * cpufreq_cpu_get(). 267 */ 268 void cpufreq_cpu_put(struct cpufreq_policy *policy) 269 { 270 kobject_put(&policy->kobj); 271 } 272 EXPORT_SYMBOL_GPL(cpufreq_cpu_put); 273 274 /********************************************************************* 275 * EXTERNALLY AFFECTING FREQUENCY CHANGES * 276 *********************************************************************/ 277 278 /** 279 * adjust_jiffies - adjust the system "loops_per_jiffy" 280 * 281 * This function alters the system "loops_per_jiffy" for the clock 282 * speed change. Note that loops_per_jiffy cannot be updated on SMP 283 * systems as each CPU might be scaled differently. So, use the arch 284 * per-CPU loops_per_jiffy value wherever possible. 285 */ 286 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 287 { 288 #ifndef CONFIG_SMP 289 static unsigned long l_p_j_ref; 290 static unsigned int l_p_j_ref_freq; 291 292 if (ci->flags & CPUFREQ_CONST_LOOPS) 293 return; 294 295 if (!l_p_j_ref_freq) { 296 l_p_j_ref = loops_per_jiffy; 297 l_p_j_ref_freq = ci->old; 298 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", 299 l_p_j_ref, l_p_j_ref_freq); 300 } 301 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) { 302 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, 303 ci->new); 304 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n", 305 loops_per_jiffy, ci->new); 306 } 307 #endif 308 } 309 310 static void __cpufreq_notify_transition(struct cpufreq_policy *policy, 311 struct cpufreq_freqs *freqs, unsigned int state) 312 { 313 BUG_ON(irqs_disabled()); 314 315 if (cpufreq_disabled()) 316 return; 317 318 freqs->flags = cpufreq_driver->flags; 319 pr_debug("notification %u of frequency transition to %u kHz\n", 320 state, freqs->new); 321 322 switch (state) { 323 324 case CPUFREQ_PRECHANGE: 325 /* detect if the driver reported a value as "old frequency" 326 * which is not equal to what the cpufreq core thinks is 327 * "old frequency". 328 */ 329 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 330 if ((policy) && (policy->cpu == freqs->cpu) && 331 (policy->cur) && (policy->cur != freqs->old)) { 332 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n", 333 freqs->old, policy->cur); 334 freqs->old = policy->cur; 335 } 336 } 337 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 338 CPUFREQ_PRECHANGE, freqs); 339 adjust_jiffies(CPUFREQ_PRECHANGE, freqs); 340 break; 341 342 case CPUFREQ_POSTCHANGE: 343 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); 344 pr_debug("FREQ: %lu - CPU: %lu\n", 345 (unsigned long)freqs->new, (unsigned long)freqs->cpu); 346 trace_cpu_frequency(freqs->new, freqs->cpu); 347 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 348 CPUFREQ_POSTCHANGE, freqs); 349 if (likely(policy) && likely(policy->cpu == freqs->cpu)) 350 policy->cur = freqs->new; 351 break; 352 } 353 } 354 355 /** 356 * cpufreq_notify_transition - call notifier chain and adjust_jiffies 357 * on frequency transition. 358 * 359 * This function calls the transition notifiers and the "adjust_jiffies" 360 * function. It is called twice on all CPU frequency changes that have 361 * external effects. 362 */ 363 static void cpufreq_notify_transition(struct cpufreq_policy *policy, 364 struct cpufreq_freqs *freqs, unsigned int state) 365 { 366 for_each_cpu(freqs->cpu, policy->cpus) 367 __cpufreq_notify_transition(policy, freqs, state); 368 } 369 370 /* Do post notifications when there are chances that transition has failed */ 371 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy, 372 struct cpufreq_freqs *freqs, int transition_failed) 373 { 374 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); 375 if (!transition_failed) 376 return; 377 378 swap(freqs->old, freqs->new); 379 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); 380 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE); 381 } 382 383 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy, 384 struct cpufreq_freqs *freqs) 385 { 386 387 /* 388 * Catch double invocations of _begin() which lead to self-deadlock. 389 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core 390 * doesn't invoke _begin() on their behalf, and hence the chances of 391 * double invocations are very low. Moreover, there are scenarios 392 * where these checks can emit false-positive warnings in these 393 * drivers; so we avoid that by skipping them altogether. 394 */ 395 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION) 396 && current == policy->transition_task); 397 398 wait: 399 wait_event(policy->transition_wait, !policy->transition_ongoing); 400 401 spin_lock(&policy->transition_lock); 402 403 if (unlikely(policy->transition_ongoing)) { 404 spin_unlock(&policy->transition_lock); 405 goto wait; 406 } 407 408 policy->transition_ongoing = true; 409 policy->transition_task = current; 410 411 spin_unlock(&policy->transition_lock); 412 413 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); 414 } 415 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); 416 417 void cpufreq_freq_transition_end(struct cpufreq_policy *policy, 418 struct cpufreq_freqs *freqs, int transition_failed) 419 { 420 if (unlikely(WARN_ON(!policy->transition_ongoing))) 421 return; 422 423 cpufreq_notify_post_transition(policy, freqs, transition_failed); 424 425 policy->transition_ongoing = false; 426 policy->transition_task = NULL; 427 428 wake_up(&policy->transition_wait); 429 } 430 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end); 431 432 433 /********************************************************************* 434 * SYSFS INTERFACE * 435 *********************************************************************/ 436 static ssize_t show_boost(struct kobject *kobj, 437 struct attribute *attr, char *buf) 438 { 439 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled); 440 } 441 442 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr, 443 const char *buf, size_t count) 444 { 445 int ret, enable; 446 447 ret = sscanf(buf, "%d", &enable); 448 if (ret != 1 || enable < 0 || enable > 1) 449 return -EINVAL; 450 451 if (cpufreq_boost_trigger_state(enable)) { 452 pr_err("%s: Cannot %s BOOST!\n", 453 __func__, enable ? "enable" : "disable"); 454 return -EINVAL; 455 } 456 457 pr_debug("%s: cpufreq BOOST %s\n", 458 __func__, enable ? "enabled" : "disabled"); 459 460 return count; 461 } 462 define_one_global_rw(boost); 463 464 static struct cpufreq_governor *find_governor(const char *str_governor) 465 { 466 struct cpufreq_governor *t; 467 468 for_each_governor(t) 469 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN)) 470 return t; 471 472 return NULL; 473 } 474 475 /** 476 * cpufreq_parse_governor - parse a governor string 477 */ 478 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, 479 struct cpufreq_governor **governor) 480 { 481 int err = -EINVAL; 482 483 if (cpufreq_driver->setpolicy) { 484 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { 485 *policy = CPUFREQ_POLICY_PERFORMANCE; 486 err = 0; 487 } else if (!strncasecmp(str_governor, "powersave", 488 CPUFREQ_NAME_LEN)) { 489 *policy = CPUFREQ_POLICY_POWERSAVE; 490 err = 0; 491 } 492 } else { 493 struct cpufreq_governor *t; 494 495 mutex_lock(&cpufreq_governor_mutex); 496 497 t = find_governor(str_governor); 498 499 if (t == NULL) { 500 int ret; 501 502 mutex_unlock(&cpufreq_governor_mutex); 503 ret = request_module("cpufreq_%s", str_governor); 504 mutex_lock(&cpufreq_governor_mutex); 505 506 if (ret == 0) 507 t = find_governor(str_governor); 508 } 509 510 if (t != NULL) { 511 *governor = t; 512 err = 0; 513 } 514 515 mutex_unlock(&cpufreq_governor_mutex); 516 } 517 return err; 518 } 519 520 /** 521 * cpufreq_per_cpu_attr_read() / show_##file_name() - 522 * print out cpufreq information 523 * 524 * Write out information from cpufreq_driver->policy[cpu]; object must be 525 * "unsigned int". 526 */ 527 528 #define show_one(file_name, object) \ 529 static ssize_t show_##file_name \ 530 (struct cpufreq_policy *policy, char *buf) \ 531 { \ 532 return sprintf(buf, "%u\n", policy->object); \ 533 } 534 535 show_one(cpuinfo_min_freq, cpuinfo.min_freq); 536 show_one(cpuinfo_max_freq, cpuinfo.max_freq); 537 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); 538 show_one(scaling_min_freq, min); 539 show_one(scaling_max_freq, max); 540 541 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) 542 { 543 ssize_t ret; 544 545 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) 546 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu)); 547 else 548 ret = sprintf(buf, "%u\n", policy->cur); 549 return ret; 550 } 551 552 static int cpufreq_set_policy(struct cpufreq_policy *policy, 553 struct cpufreq_policy *new_policy); 554 555 /** 556 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access 557 */ 558 #define store_one(file_name, object) \ 559 static ssize_t store_##file_name \ 560 (struct cpufreq_policy *policy, const char *buf, size_t count) \ 561 { \ 562 int ret, temp; \ 563 struct cpufreq_policy new_policy; \ 564 \ 565 memcpy(&new_policy, policy, sizeof(*policy)); \ 566 \ 567 ret = sscanf(buf, "%u", &new_policy.object); \ 568 if (ret != 1) \ 569 return -EINVAL; \ 570 \ 571 temp = new_policy.object; \ 572 ret = cpufreq_set_policy(policy, &new_policy); \ 573 if (!ret) \ 574 policy->user_policy.object = temp; \ 575 \ 576 return ret ? ret : count; \ 577 } 578 579 store_one(scaling_min_freq, min); 580 store_one(scaling_max_freq, max); 581 582 /** 583 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware 584 */ 585 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, 586 char *buf) 587 { 588 unsigned int cur_freq = __cpufreq_get(policy); 589 if (!cur_freq) 590 return sprintf(buf, "<unknown>"); 591 return sprintf(buf, "%u\n", cur_freq); 592 } 593 594 /** 595 * show_scaling_governor - show the current policy for the specified CPU 596 */ 597 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) 598 { 599 if (policy->policy == CPUFREQ_POLICY_POWERSAVE) 600 return sprintf(buf, "powersave\n"); 601 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) 602 return sprintf(buf, "performance\n"); 603 else if (policy->governor) 604 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", 605 policy->governor->name); 606 return -EINVAL; 607 } 608 609 /** 610 * store_scaling_governor - store policy for the specified CPU 611 */ 612 static ssize_t store_scaling_governor(struct cpufreq_policy *policy, 613 const char *buf, size_t count) 614 { 615 int ret; 616 char str_governor[16]; 617 struct cpufreq_policy new_policy; 618 619 memcpy(&new_policy, policy, sizeof(*policy)); 620 621 ret = sscanf(buf, "%15s", str_governor); 622 if (ret != 1) 623 return -EINVAL; 624 625 if (cpufreq_parse_governor(str_governor, &new_policy.policy, 626 &new_policy.governor)) 627 return -EINVAL; 628 629 ret = cpufreq_set_policy(policy, &new_policy); 630 return ret ? ret : count; 631 } 632 633 /** 634 * show_scaling_driver - show the cpufreq driver currently loaded 635 */ 636 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) 637 { 638 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); 639 } 640 641 /** 642 * show_scaling_available_governors - show the available CPUfreq governors 643 */ 644 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, 645 char *buf) 646 { 647 ssize_t i = 0; 648 struct cpufreq_governor *t; 649 650 if (!has_target()) { 651 i += sprintf(buf, "performance powersave"); 652 goto out; 653 } 654 655 for_each_governor(t) { 656 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) 657 - (CPUFREQ_NAME_LEN + 2))) 658 goto out; 659 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name); 660 } 661 out: 662 i += sprintf(&buf[i], "\n"); 663 return i; 664 } 665 666 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) 667 { 668 ssize_t i = 0; 669 unsigned int cpu; 670 671 for_each_cpu(cpu, mask) { 672 if (i) 673 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); 674 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); 675 if (i >= (PAGE_SIZE - 5)) 676 break; 677 } 678 i += sprintf(&buf[i], "\n"); 679 return i; 680 } 681 EXPORT_SYMBOL_GPL(cpufreq_show_cpus); 682 683 /** 684 * show_related_cpus - show the CPUs affected by each transition even if 685 * hw coordination is in use 686 */ 687 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) 688 { 689 return cpufreq_show_cpus(policy->related_cpus, buf); 690 } 691 692 /** 693 * show_affected_cpus - show the CPUs affected by each transition 694 */ 695 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf) 696 { 697 return cpufreq_show_cpus(policy->cpus, buf); 698 } 699 700 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy, 701 const char *buf, size_t count) 702 { 703 unsigned int freq = 0; 704 unsigned int ret; 705 706 if (!policy->governor || !policy->governor->store_setspeed) 707 return -EINVAL; 708 709 ret = sscanf(buf, "%u", &freq); 710 if (ret != 1) 711 return -EINVAL; 712 713 policy->governor->store_setspeed(policy, freq); 714 715 return count; 716 } 717 718 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) 719 { 720 if (!policy->governor || !policy->governor->show_setspeed) 721 return sprintf(buf, "<unsupported>\n"); 722 723 return policy->governor->show_setspeed(policy, buf); 724 } 725 726 /** 727 * show_bios_limit - show the current cpufreq HW/BIOS limitation 728 */ 729 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) 730 { 731 unsigned int limit; 732 int ret; 733 if (cpufreq_driver->bios_limit) { 734 ret = cpufreq_driver->bios_limit(policy->cpu, &limit); 735 if (!ret) 736 return sprintf(buf, "%u\n", limit); 737 } 738 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq); 739 } 740 741 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400); 742 cpufreq_freq_attr_ro(cpuinfo_min_freq); 743 cpufreq_freq_attr_ro(cpuinfo_max_freq); 744 cpufreq_freq_attr_ro(cpuinfo_transition_latency); 745 cpufreq_freq_attr_ro(scaling_available_governors); 746 cpufreq_freq_attr_ro(scaling_driver); 747 cpufreq_freq_attr_ro(scaling_cur_freq); 748 cpufreq_freq_attr_ro(bios_limit); 749 cpufreq_freq_attr_ro(related_cpus); 750 cpufreq_freq_attr_ro(affected_cpus); 751 cpufreq_freq_attr_rw(scaling_min_freq); 752 cpufreq_freq_attr_rw(scaling_max_freq); 753 cpufreq_freq_attr_rw(scaling_governor); 754 cpufreq_freq_attr_rw(scaling_setspeed); 755 756 static struct attribute *default_attrs[] = { 757 &cpuinfo_min_freq.attr, 758 &cpuinfo_max_freq.attr, 759 &cpuinfo_transition_latency.attr, 760 &scaling_min_freq.attr, 761 &scaling_max_freq.attr, 762 &affected_cpus.attr, 763 &related_cpus.attr, 764 &scaling_governor.attr, 765 &scaling_driver.attr, 766 &scaling_available_governors.attr, 767 &scaling_setspeed.attr, 768 NULL 769 }; 770 771 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) 772 #define to_attr(a) container_of(a, struct freq_attr, attr) 773 774 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) 775 { 776 struct cpufreq_policy *policy = to_policy(kobj); 777 struct freq_attr *fattr = to_attr(attr); 778 ssize_t ret; 779 780 down_read(&policy->rwsem); 781 ret = fattr->show(policy, buf); 782 up_read(&policy->rwsem); 783 784 return ret; 785 } 786 787 static ssize_t store(struct kobject *kobj, struct attribute *attr, 788 const char *buf, size_t count) 789 { 790 struct cpufreq_policy *policy = to_policy(kobj); 791 struct freq_attr *fattr = to_attr(attr); 792 ssize_t ret = -EINVAL; 793 794 get_online_cpus(); 795 796 if (cpu_online(policy->cpu)) { 797 down_write(&policy->rwsem); 798 ret = fattr->store(policy, buf, count); 799 up_write(&policy->rwsem); 800 } 801 802 put_online_cpus(); 803 804 return ret; 805 } 806 807 static void cpufreq_sysfs_release(struct kobject *kobj) 808 { 809 struct cpufreq_policy *policy = to_policy(kobj); 810 pr_debug("last reference is dropped\n"); 811 complete(&policy->kobj_unregister); 812 } 813 814 static const struct sysfs_ops sysfs_ops = { 815 .show = show, 816 .store = store, 817 }; 818 819 static struct kobj_type ktype_cpufreq = { 820 .sysfs_ops = &sysfs_ops, 821 .default_attrs = default_attrs, 822 .release = cpufreq_sysfs_release, 823 }; 824 825 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu) 826 { 827 struct device *cpu_dev; 828 829 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu); 830 831 if (!policy) 832 return 0; 833 834 cpu_dev = get_cpu_device(cpu); 835 if (WARN_ON(!cpu_dev)) 836 return 0; 837 838 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); 839 } 840 841 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu) 842 { 843 struct device *cpu_dev; 844 845 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu); 846 847 cpu_dev = get_cpu_device(cpu); 848 if (WARN_ON(!cpu_dev)) 849 return; 850 851 sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); 852 } 853 854 /* Add/remove symlinks for all related CPUs */ 855 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) 856 { 857 unsigned int j; 858 int ret = 0; 859 860 /* Some related CPUs might not be present (physically hotplugged) */ 861 for_each_cpu(j, policy->real_cpus) { 862 ret = add_cpu_dev_symlink(policy, j); 863 if (ret) 864 break; 865 } 866 867 return ret; 868 } 869 870 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy) 871 { 872 unsigned int j; 873 874 /* Some related CPUs might not be present (physically hotplugged) */ 875 for_each_cpu(j, policy->real_cpus) 876 remove_cpu_dev_symlink(policy, j); 877 } 878 879 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy) 880 { 881 struct freq_attr **drv_attr; 882 int ret = 0; 883 884 /* set up files for this cpu device */ 885 drv_attr = cpufreq_driver->attr; 886 while (drv_attr && *drv_attr) { 887 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); 888 if (ret) 889 return ret; 890 drv_attr++; 891 } 892 if (cpufreq_driver->get) { 893 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); 894 if (ret) 895 return ret; 896 } 897 898 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); 899 if (ret) 900 return ret; 901 902 if (cpufreq_driver->bios_limit) { 903 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); 904 if (ret) 905 return ret; 906 } 907 908 return cpufreq_add_dev_symlink(policy); 909 } 910 911 __weak struct cpufreq_governor *cpufreq_default_governor(void) 912 { 913 return NULL; 914 } 915 916 static int cpufreq_init_policy(struct cpufreq_policy *policy) 917 { 918 struct cpufreq_governor *gov = NULL; 919 struct cpufreq_policy new_policy; 920 921 memcpy(&new_policy, policy, sizeof(*policy)); 922 923 /* Update governor of new_policy to the governor used before hotplug */ 924 gov = find_governor(policy->last_governor); 925 if (gov) { 926 pr_debug("Restoring governor %s for cpu %d\n", 927 policy->governor->name, policy->cpu); 928 } else { 929 gov = cpufreq_default_governor(); 930 if (!gov) 931 return -ENODATA; 932 } 933 934 new_policy.governor = gov; 935 936 /* Use the default policy if there is no last_policy. */ 937 if (cpufreq_driver->setpolicy) { 938 if (policy->last_policy) 939 new_policy.policy = policy->last_policy; 940 else 941 cpufreq_parse_governor(gov->name, &new_policy.policy, 942 NULL); 943 } 944 /* set default policy */ 945 return cpufreq_set_policy(policy, &new_policy); 946 } 947 948 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) 949 { 950 int ret = 0; 951 952 /* Has this CPU been taken care of already? */ 953 if (cpumask_test_cpu(cpu, policy->cpus)) 954 return 0; 955 956 down_write(&policy->rwsem); 957 if (has_target()) { 958 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP); 959 if (ret) { 960 pr_err("%s: Failed to stop governor\n", __func__); 961 goto unlock; 962 } 963 } 964 965 cpumask_set_cpu(cpu, policy->cpus); 966 967 if (has_target()) { 968 ret = cpufreq_start_governor(policy); 969 if (ret) 970 pr_err("%s: Failed to start governor\n", __func__); 971 } 972 973 unlock: 974 up_write(&policy->rwsem); 975 return ret; 976 } 977 978 static void handle_update(struct work_struct *work) 979 { 980 struct cpufreq_policy *policy = 981 container_of(work, struct cpufreq_policy, update); 982 unsigned int cpu = policy->cpu; 983 pr_debug("handle_update for cpu %u called\n", cpu); 984 cpufreq_update_policy(cpu); 985 } 986 987 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu) 988 { 989 struct device *dev = get_cpu_device(cpu); 990 struct cpufreq_policy *policy; 991 int ret; 992 993 if (WARN_ON(!dev)) 994 return NULL; 995 996 policy = kzalloc(sizeof(*policy), GFP_KERNEL); 997 if (!policy) 998 return NULL; 999 1000 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) 1001 goto err_free_policy; 1002 1003 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) 1004 goto err_free_cpumask; 1005 1006 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL)) 1007 goto err_free_rcpumask; 1008 1009 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, 1010 cpufreq_global_kobject, "policy%u", cpu); 1011 if (ret) { 1012 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret); 1013 goto err_free_real_cpus; 1014 } 1015 1016 INIT_LIST_HEAD(&policy->policy_list); 1017 init_rwsem(&policy->rwsem); 1018 spin_lock_init(&policy->transition_lock); 1019 init_waitqueue_head(&policy->transition_wait); 1020 init_completion(&policy->kobj_unregister); 1021 INIT_WORK(&policy->update, handle_update); 1022 1023 policy->cpu = cpu; 1024 return policy; 1025 1026 err_free_real_cpus: 1027 free_cpumask_var(policy->real_cpus); 1028 err_free_rcpumask: 1029 free_cpumask_var(policy->related_cpus); 1030 err_free_cpumask: 1031 free_cpumask_var(policy->cpus); 1032 err_free_policy: 1033 kfree(policy); 1034 1035 return NULL; 1036 } 1037 1038 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify) 1039 { 1040 struct kobject *kobj; 1041 struct completion *cmp; 1042 1043 if (notify) 1044 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1045 CPUFREQ_REMOVE_POLICY, policy); 1046 1047 down_write(&policy->rwsem); 1048 cpufreq_remove_dev_symlink(policy); 1049 kobj = &policy->kobj; 1050 cmp = &policy->kobj_unregister; 1051 up_write(&policy->rwsem); 1052 kobject_put(kobj); 1053 1054 /* 1055 * We need to make sure that the underlying kobj is 1056 * actually not referenced anymore by anybody before we 1057 * proceed with unloading. 1058 */ 1059 pr_debug("waiting for dropping of refcount\n"); 1060 wait_for_completion(cmp); 1061 pr_debug("wait complete\n"); 1062 } 1063 1064 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify) 1065 { 1066 unsigned long flags; 1067 int cpu; 1068 1069 /* Remove policy from list */ 1070 write_lock_irqsave(&cpufreq_driver_lock, flags); 1071 list_del(&policy->policy_list); 1072 1073 for_each_cpu(cpu, policy->related_cpus) 1074 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1075 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1076 1077 cpufreq_policy_put_kobj(policy, notify); 1078 free_cpumask_var(policy->real_cpus); 1079 free_cpumask_var(policy->related_cpus); 1080 free_cpumask_var(policy->cpus); 1081 kfree(policy); 1082 } 1083 1084 static int cpufreq_online(unsigned int cpu) 1085 { 1086 struct cpufreq_policy *policy; 1087 bool new_policy; 1088 unsigned long flags; 1089 unsigned int j; 1090 int ret; 1091 1092 pr_debug("%s: bringing CPU%u online\n", __func__, cpu); 1093 1094 /* Check if this CPU already has a policy to manage it */ 1095 policy = per_cpu(cpufreq_cpu_data, cpu); 1096 if (policy) { 1097 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus)); 1098 if (!policy_is_inactive(policy)) 1099 return cpufreq_add_policy_cpu(policy, cpu); 1100 1101 /* This is the only online CPU for the policy. Start over. */ 1102 new_policy = false; 1103 down_write(&policy->rwsem); 1104 policy->cpu = cpu; 1105 policy->governor = NULL; 1106 up_write(&policy->rwsem); 1107 } else { 1108 new_policy = true; 1109 policy = cpufreq_policy_alloc(cpu); 1110 if (!policy) 1111 return -ENOMEM; 1112 } 1113 1114 cpumask_copy(policy->cpus, cpumask_of(cpu)); 1115 1116 /* call driver. From then on the cpufreq must be able 1117 * to accept all calls to ->verify and ->setpolicy for this CPU 1118 */ 1119 ret = cpufreq_driver->init(policy); 1120 if (ret) { 1121 pr_debug("initialization failed\n"); 1122 goto out_free_policy; 1123 } 1124 1125 down_write(&policy->rwsem); 1126 1127 if (new_policy) { 1128 /* related_cpus should at least include policy->cpus. */ 1129 cpumask_copy(policy->related_cpus, policy->cpus); 1130 /* Remember CPUs present at the policy creation time. */ 1131 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask); 1132 } 1133 1134 /* 1135 * affected cpus must always be the one, which are online. We aren't 1136 * managing offline cpus here. 1137 */ 1138 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); 1139 1140 if (new_policy) { 1141 policy->user_policy.min = policy->min; 1142 policy->user_policy.max = policy->max; 1143 1144 write_lock_irqsave(&cpufreq_driver_lock, flags); 1145 for_each_cpu(j, policy->related_cpus) 1146 per_cpu(cpufreq_cpu_data, j) = policy; 1147 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1148 } 1149 1150 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 1151 policy->cur = cpufreq_driver->get(policy->cpu); 1152 if (!policy->cur) { 1153 pr_err("%s: ->get() failed\n", __func__); 1154 goto out_exit_policy; 1155 } 1156 } 1157 1158 /* 1159 * Sometimes boot loaders set CPU frequency to a value outside of 1160 * frequency table present with cpufreq core. In such cases CPU might be 1161 * unstable if it has to run on that frequency for long duration of time 1162 * and so its better to set it to a frequency which is specified in 1163 * freq-table. This also makes cpufreq stats inconsistent as 1164 * cpufreq-stats would fail to register because current frequency of CPU 1165 * isn't found in freq-table. 1166 * 1167 * Because we don't want this change to effect boot process badly, we go 1168 * for the next freq which is >= policy->cur ('cur' must be set by now, 1169 * otherwise we will end up setting freq to lowest of the table as 'cur' 1170 * is initialized to zero). 1171 * 1172 * We are passing target-freq as "policy->cur - 1" otherwise 1173 * __cpufreq_driver_target() would simply fail, as policy->cur will be 1174 * equal to target-freq. 1175 */ 1176 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) 1177 && has_target()) { 1178 /* Are we running at unknown frequency ? */ 1179 ret = cpufreq_frequency_table_get_index(policy, policy->cur); 1180 if (ret == -EINVAL) { 1181 /* Warn user and fix it */ 1182 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", 1183 __func__, policy->cpu, policy->cur); 1184 ret = __cpufreq_driver_target(policy, policy->cur - 1, 1185 CPUFREQ_RELATION_L); 1186 1187 /* 1188 * Reaching here after boot in a few seconds may not 1189 * mean that system will remain stable at "unknown" 1190 * frequency for longer duration. Hence, a BUG_ON(). 1191 */ 1192 BUG_ON(ret); 1193 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", 1194 __func__, policy->cpu, policy->cur); 1195 } 1196 } 1197 1198 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1199 CPUFREQ_START, policy); 1200 1201 if (new_policy) { 1202 ret = cpufreq_add_dev_interface(policy); 1203 if (ret) 1204 goto out_exit_policy; 1205 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1206 CPUFREQ_CREATE_POLICY, policy); 1207 1208 write_lock_irqsave(&cpufreq_driver_lock, flags); 1209 list_add(&policy->policy_list, &cpufreq_policy_list); 1210 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 1211 } 1212 1213 ret = cpufreq_init_policy(policy); 1214 if (ret) { 1215 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n", 1216 __func__, cpu, ret); 1217 /* cpufreq_policy_free() will notify based on this */ 1218 new_policy = false; 1219 goto out_exit_policy; 1220 } 1221 1222 up_write(&policy->rwsem); 1223 1224 kobject_uevent(&policy->kobj, KOBJ_ADD); 1225 1226 /* Callback for handling stuff after policy is ready */ 1227 if (cpufreq_driver->ready) 1228 cpufreq_driver->ready(policy); 1229 1230 pr_debug("initialization complete\n"); 1231 1232 return 0; 1233 1234 out_exit_policy: 1235 up_write(&policy->rwsem); 1236 1237 if (cpufreq_driver->exit) 1238 cpufreq_driver->exit(policy); 1239 out_free_policy: 1240 cpufreq_policy_free(policy, !new_policy); 1241 return ret; 1242 } 1243 1244 /** 1245 * cpufreq_add_dev - the cpufreq interface for a CPU device. 1246 * @dev: CPU device. 1247 * @sif: Subsystem interface structure pointer (not used) 1248 */ 1249 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 1250 { 1251 unsigned cpu = dev->id; 1252 int ret; 1253 1254 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu); 1255 1256 if (cpu_online(cpu)) { 1257 ret = cpufreq_online(cpu); 1258 } else { 1259 /* 1260 * A hotplug notifier will follow and we will handle it as CPU 1261 * online then. For now, just create the sysfs link, unless 1262 * there is no policy or the link is already present. 1263 */ 1264 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1265 1266 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus) 1267 ? add_cpu_dev_symlink(policy, cpu) : 0; 1268 } 1269 1270 return ret; 1271 } 1272 1273 static void cpufreq_offline(unsigned int cpu) 1274 { 1275 struct cpufreq_policy *policy; 1276 int ret; 1277 1278 pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 1279 1280 policy = cpufreq_cpu_get_raw(cpu); 1281 if (!policy) { 1282 pr_debug("%s: No cpu_data found\n", __func__); 1283 return; 1284 } 1285 1286 down_write(&policy->rwsem); 1287 if (has_target()) { 1288 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP); 1289 if (ret) 1290 pr_err("%s: Failed to stop governor\n", __func__); 1291 } 1292 1293 cpumask_clear_cpu(cpu, policy->cpus); 1294 1295 if (policy_is_inactive(policy)) { 1296 if (has_target()) 1297 strncpy(policy->last_governor, policy->governor->name, 1298 CPUFREQ_NAME_LEN); 1299 else 1300 policy->last_policy = policy->policy; 1301 } else if (cpu == policy->cpu) { 1302 /* Nominate new CPU */ 1303 policy->cpu = cpumask_any(policy->cpus); 1304 } 1305 1306 /* Start governor again for active policy */ 1307 if (!policy_is_inactive(policy)) { 1308 if (has_target()) { 1309 ret = cpufreq_start_governor(policy); 1310 if (ret) 1311 pr_err("%s: Failed to start governor\n", __func__); 1312 } 1313 1314 goto unlock; 1315 } 1316 1317 if (cpufreq_driver->stop_cpu) 1318 cpufreq_driver->stop_cpu(policy); 1319 1320 /* If cpu is last user of policy, free policy */ 1321 if (has_target()) { 1322 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 1323 if (ret) 1324 pr_err("%s: Failed to exit governor\n", __func__); 1325 } 1326 1327 /* 1328 * Perform the ->exit() even during light-weight tear-down, 1329 * since this is a core component, and is essential for the 1330 * subsequent light-weight ->init() to succeed. 1331 */ 1332 if (cpufreq_driver->exit) { 1333 cpufreq_driver->exit(policy); 1334 policy->freq_table = NULL; 1335 } 1336 1337 unlock: 1338 up_write(&policy->rwsem); 1339 } 1340 1341 /** 1342 * cpufreq_remove_dev - remove a CPU device 1343 * 1344 * Removes the cpufreq interface for a CPU device. 1345 */ 1346 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 1347 { 1348 unsigned int cpu = dev->id; 1349 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1350 1351 if (!policy) 1352 return; 1353 1354 if (cpu_online(cpu)) 1355 cpufreq_offline(cpu); 1356 1357 cpumask_clear_cpu(cpu, policy->real_cpus); 1358 remove_cpu_dev_symlink(policy, cpu); 1359 1360 if (cpumask_empty(policy->real_cpus)) 1361 cpufreq_policy_free(policy, true); 1362 } 1363 1364 /** 1365 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're 1366 * in deep trouble. 1367 * @policy: policy managing CPUs 1368 * @new_freq: CPU frequency the CPU actually runs at 1369 * 1370 * We adjust to current frequency first, and need to clean up later. 1371 * So either call to cpufreq_update_policy() or schedule handle_update()). 1372 */ 1373 static void cpufreq_out_of_sync(struct cpufreq_policy *policy, 1374 unsigned int new_freq) 1375 { 1376 struct cpufreq_freqs freqs; 1377 1378 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n", 1379 policy->cur, new_freq); 1380 1381 freqs.old = policy->cur; 1382 freqs.new = new_freq; 1383 1384 cpufreq_freq_transition_begin(policy, &freqs); 1385 cpufreq_freq_transition_end(policy, &freqs, 0); 1386 } 1387 1388 /** 1389 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1390 * @cpu: CPU number 1391 * 1392 * This is the last known freq, without actually getting it from the driver. 1393 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1394 */ 1395 unsigned int cpufreq_quick_get(unsigned int cpu) 1396 { 1397 struct cpufreq_policy *policy; 1398 unsigned int ret_freq = 0; 1399 unsigned long flags; 1400 1401 read_lock_irqsave(&cpufreq_driver_lock, flags); 1402 1403 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) { 1404 ret_freq = cpufreq_driver->get(cpu); 1405 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1406 return ret_freq; 1407 } 1408 1409 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1410 1411 policy = cpufreq_cpu_get(cpu); 1412 if (policy) { 1413 ret_freq = policy->cur; 1414 cpufreq_cpu_put(policy); 1415 } 1416 1417 return ret_freq; 1418 } 1419 EXPORT_SYMBOL(cpufreq_quick_get); 1420 1421 /** 1422 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU 1423 * @cpu: CPU number 1424 * 1425 * Just return the max possible frequency for a given CPU. 1426 */ 1427 unsigned int cpufreq_quick_get_max(unsigned int cpu) 1428 { 1429 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1430 unsigned int ret_freq = 0; 1431 1432 if (policy) { 1433 ret_freq = policy->max; 1434 cpufreq_cpu_put(policy); 1435 } 1436 1437 return ret_freq; 1438 } 1439 EXPORT_SYMBOL(cpufreq_quick_get_max); 1440 1441 static unsigned int __cpufreq_get(struct cpufreq_policy *policy) 1442 { 1443 unsigned int ret_freq = 0; 1444 1445 if (!cpufreq_driver->get) 1446 return ret_freq; 1447 1448 ret_freq = cpufreq_driver->get(policy->cpu); 1449 1450 /* Updating inactive policies is invalid, so avoid doing that. */ 1451 if (unlikely(policy_is_inactive(policy))) 1452 return ret_freq; 1453 1454 if (ret_freq && policy->cur && 1455 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1456 /* verify no discrepancy between actual and 1457 saved value exists */ 1458 if (unlikely(ret_freq != policy->cur)) { 1459 cpufreq_out_of_sync(policy, ret_freq); 1460 schedule_work(&policy->update); 1461 } 1462 } 1463 1464 return ret_freq; 1465 } 1466 1467 /** 1468 * cpufreq_get - get the current CPU frequency (in kHz) 1469 * @cpu: CPU number 1470 * 1471 * Get the CPU current (static) CPU frequency 1472 */ 1473 unsigned int cpufreq_get(unsigned int cpu) 1474 { 1475 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1476 unsigned int ret_freq = 0; 1477 1478 if (policy) { 1479 down_read(&policy->rwsem); 1480 ret_freq = __cpufreq_get(policy); 1481 up_read(&policy->rwsem); 1482 1483 cpufreq_cpu_put(policy); 1484 } 1485 1486 return ret_freq; 1487 } 1488 EXPORT_SYMBOL(cpufreq_get); 1489 1490 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy) 1491 { 1492 unsigned int new_freq; 1493 1494 new_freq = cpufreq_driver->get(policy->cpu); 1495 if (!new_freq) 1496 return 0; 1497 1498 if (!policy->cur) { 1499 pr_debug("cpufreq: Driver did not initialize current freq\n"); 1500 policy->cur = new_freq; 1501 } else if (policy->cur != new_freq && has_target()) { 1502 cpufreq_out_of_sync(policy, new_freq); 1503 } 1504 1505 return new_freq; 1506 } 1507 1508 static struct subsys_interface cpufreq_interface = { 1509 .name = "cpufreq", 1510 .subsys = &cpu_subsys, 1511 .add_dev = cpufreq_add_dev, 1512 .remove_dev = cpufreq_remove_dev, 1513 }; 1514 1515 /* 1516 * In case platform wants some specific frequency to be configured 1517 * during suspend.. 1518 */ 1519 int cpufreq_generic_suspend(struct cpufreq_policy *policy) 1520 { 1521 int ret; 1522 1523 if (!policy->suspend_freq) { 1524 pr_debug("%s: suspend_freq not defined\n", __func__); 1525 return 0; 1526 } 1527 1528 pr_debug("%s: Setting suspend-freq: %u\n", __func__, 1529 policy->suspend_freq); 1530 1531 ret = __cpufreq_driver_target(policy, policy->suspend_freq, 1532 CPUFREQ_RELATION_H); 1533 if (ret) 1534 pr_err("%s: unable to set suspend-freq: %u. err: %d\n", 1535 __func__, policy->suspend_freq, ret); 1536 1537 return ret; 1538 } 1539 EXPORT_SYMBOL(cpufreq_generic_suspend); 1540 1541 /** 1542 * cpufreq_suspend() - Suspend CPUFreq governors 1543 * 1544 * Called during system wide Suspend/Hibernate cycles for suspending governors 1545 * as some platforms can't change frequency after this point in suspend cycle. 1546 * Because some of the devices (like: i2c, regulators, etc) they use for 1547 * changing frequency are suspended quickly after this point. 1548 */ 1549 void cpufreq_suspend(void) 1550 { 1551 struct cpufreq_policy *policy; 1552 int ret; 1553 1554 if (!cpufreq_driver) 1555 return; 1556 1557 if (!has_target()) 1558 goto suspend; 1559 1560 pr_debug("%s: Suspending Governors\n", __func__); 1561 1562 for_each_active_policy(policy) { 1563 down_write(&policy->rwsem); 1564 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP); 1565 up_write(&policy->rwsem); 1566 1567 if (ret) 1568 pr_err("%s: Failed to stop governor for policy: %p\n", 1569 __func__, policy); 1570 else if (cpufreq_driver->suspend 1571 && cpufreq_driver->suspend(policy)) 1572 pr_err("%s: Failed to suspend driver: %p\n", __func__, 1573 policy); 1574 } 1575 1576 suspend: 1577 cpufreq_suspended = true; 1578 } 1579 1580 /** 1581 * cpufreq_resume() - Resume CPUFreq governors 1582 * 1583 * Called during system wide Suspend/Hibernate cycle for resuming governors that 1584 * are suspended with cpufreq_suspend(). 1585 */ 1586 void cpufreq_resume(void) 1587 { 1588 struct cpufreq_policy *policy; 1589 int ret; 1590 1591 if (!cpufreq_driver) 1592 return; 1593 1594 cpufreq_suspended = false; 1595 1596 if (!has_target()) 1597 return; 1598 1599 pr_debug("%s: Resuming Governors\n", __func__); 1600 1601 for_each_active_policy(policy) { 1602 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) { 1603 pr_err("%s: Failed to resume driver: %p\n", __func__, 1604 policy); 1605 } else { 1606 down_write(&policy->rwsem); 1607 ret = cpufreq_start_governor(policy); 1608 up_write(&policy->rwsem); 1609 1610 if (ret) 1611 pr_err("%s: Failed to start governor for policy: %p\n", 1612 __func__, policy); 1613 } 1614 } 1615 } 1616 1617 /** 1618 * cpufreq_get_current_driver - return current driver's name 1619 * 1620 * Return the name string of the currently loaded cpufreq driver 1621 * or NULL, if none. 1622 */ 1623 const char *cpufreq_get_current_driver(void) 1624 { 1625 if (cpufreq_driver) 1626 return cpufreq_driver->name; 1627 1628 return NULL; 1629 } 1630 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); 1631 1632 /** 1633 * cpufreq_get_driver_data - return current driver data 1634 * 1635 * Return the private data of the currently loaded cpufreq 1636 * driver, or NULL if no cpufreq driver is loaded. 1637 */ 1638 void *cpufreq_get_driver_data(void) 1639 { 1640 if (cpufreq_driver) 1641 return cpufreq_driver->driver_data; 1642 1643 return NULL; 1644 } 1645 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data); 1646 1647 /********************************************************************* 1648 * NOTIFIER LISTS INTERFACE * 1649 *********************************************************************/ 1650 1651 /** 1652 * cpufreq_register_notifier - register a driver with cpufreq 1653 * @nb: notifier function to register 1654 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1655 * 1656 * Add a driver to one of two lists: either a list of drivers that 1657 * are notified about clock rate changes (once before and once after 1658 * the transition), or a list of drivers that are notified about 1659 * changes in cpufreq policy. 1660 * 1661 * This function may sleep, and has the same return conditions as 1662 * blocking_notifier_chain_register. 1663 */ 1664 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1665 { 1666 int ret; 1667 1668 if (cpufreq_disabled()) 1669 return -EINVAL; 1670 1671 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1672 1673 switch (list) { 1674 case CPUFREQ_TRANSITION_NOTIFIER: 1675 ret = srcu_notifier_chain_register( 1676 &cpufreq_transition_notifier_list, nb); 1677 break; 1678 case CPUFREQ_POLICY_NOTIFIER: 1679 ret = blocking_notifier_chain_register( 1680 &cpufreq_policy_notifier_list, nb); 1681 break; 1682 default: 1683 ret = -EINVAL; 1684 } 1685 1686 return ret; 1687 } 1688 EXPORT_SYMBOL(cpufreq_register_notifier); 1689 1690 /** 1691 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1692 * @nb: notifier block to be unregistered 1693 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1694 * 1695 * Remove a driver from the CPU frequency notifier list. 1696 * 1697 * This function may sleep, and has the same return conditions as 1698 * blocking_notifier_chain_unregister. 1699 */ 1700 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1701 { 1702 int ret; 1703 1704 if (cpufreq_disabled()) 1705 return -EINVAL; 1706 1707 switch (list) { 1708 case CPUFREQ_TRANSITION_NOTIFIER: 1709 ret = srcu_notifier_chain_unregister( 1710 &cpufreq_transition_notifier_list, nb); 1711 break; 1712 case CPUFREQ_POLICY_NOTIFIER: 1713 ret = blocking_notifier_chain_unregister( 1714 &cpufreq_policy_notifier_list, nb); 1715 break; 1716 default: 1717 ret = -EINVAL; 1718 } 1719 1720 return ret; 1721 } 1722 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1723 1724 1725 /********************************************************************* 1726 * GOVERNORS * 1727 *********************************************************************/ 1728 1729 /* Must set freqs->new to intermediate frequency */ 1730 static int __target_intermediate(struct cpufreq_policy *policy, 1731 struct cpufreq_freqs *freqs, int index) 1732 { 1733 int ret; 1734 1735 freqs->new = cpufreq_driver->get_intermediate(policy, index); 1736 1737 /* We don't need to switch to intermediate freq */ 1738 if (!freqs->new) 1739 return 0; 1740 1741 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n", 1742 __func__, policy->cpu, freqs->old, freqs->new); 1743 1744 cpufreq_freq_transition_begin(policy, freqs); 1745 ret = cpufreq_driver->target_intermediate(policy, index); 1746 cpufreq_freq_transition_end(policy, freqs, ret); 1747 1748 if (ret) 1749 pr_err("%s: Failed to change to intermediate frequency: %d\n", 1750 __func__, ret); 1751 1752 return ret; 1753 } 1754 1755 static int __target_index(struct cpufreq_policy *policy, 1756 struct cpufreq_frequency_table *freq_table, int index) 1757 { 1758 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0}; 1759 unsigned int intermediate_freq = 0; 1760 int retval = -EINVAL; 1761 bool notify; 1762 1763 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); 1764 if (notify) { 1765 /* Handle switching to intermediate frequency */ 1766 if (cpufreq_driver->get_intermediate) { 1767 retval = __target_intermediate(policy, &freqs, index); 1768 if (retval) 1769 return retval; 1770 1771 intermediate_freq = freqs.new; 1772 /* Set old freq to intermediate */ 1773 if (intermediate_freq) 1774 freqs.old = freqs.new; 1775 } 1776 1777 freqs.new = freq_table[index].frequency; 1778 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", 1779 __func__, policy->cpu, freqs.old, freqs.new); 1780 1781 cpufreq_freq_transition_begin(policy, &freqs); 1782 } 1783 1784 retval = cpufreq_driver->target_index(policy, index); 1785 if (retval) 1786 pr_err("%s: Failed to change cpu frequency: %d\n", __func__, 1787 retval); 1788 1789 if (notify) { 1790 cpufreq_freq_transition_end(policy, &freqs, retval); 1791 1792 /* 1793 * Failed after setting to intermediate freq? Driver should have 1794 * reverted back to initial frequency and so should we. Check 1795 * here for intermediate_freq instead of get_intermediate, in 1796 * case we haven't switched to intermediate freq at all. 1797 */ 1798 if (unlikely(retval && intermediate_freq)) { 1799 freqs.old = intermediate_freq; 1800 freqs.new = policy->restore_freq; 1801 cpufreq_freq_transition_begin(policy, &freqs); 1802 cpufreq_freq_transition_end(policy, &freqs, 0); 1803 } 1804 } 1805 1806 return retval; 1807 } 1808 1809 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1810 unsigned int target_freq, 1811 unsigned int relation) 1812 { 1813 unsigned int old_target_freq = target_freq; 1814 struct cpufreq_frequency_table *freq_table; 1815 int index, retval; 1816 1817 if (cpufreq_disabled()) 1818 return -ENODEV; 1819 1820 /* Make sure that target_freq is within supported range */ 1821 if (target_freq > policy->max) 1822 target_freq = policy->max; 1823 if (target_freq < policy->min) 1824 target_freq = policy->min; 1825 1826 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", 1827 policy->cpu, target_freq, relation, old_target_freq); 1828 1829 /* 1830 * This might look like a redundant call as we are checking it again 1831 * after finding index. But it is left intentionally for cases where 1832 * exactly same freq is called again and so we can save on few function 1833 * calls. 1834 */ 1835 if (target_freq == policy->cur) 1836 return 0; 1837 1838 /* Save last value to restore later on errors */ 1839 policy->restore_freq = policy->cur; 1840 1841 if (cpufreq_driver->target) 1842 return cpufreq_driver->target(policy, target_freq, relation); 1843 1844 if (!cpufreq_driver->target_index) 1845 return -EINVAL; 1846 1847 freq_table = cpufreq_frequency_get_table(policy->cpu); 1848 if (unlikely(!freq_table)) { 1849 pr_err("%s: Unable to find freq_table\n", __func__); 1850 return -EINVAL; 1851 } 1852 1853 retval = cpufreq_frequency_table_target(policy, freq_table, target_freq, 1854 relation, &index); 1855 if (unlikely(retval)) { 1856 pr_err("%s: Unable to find matching freq\n", __func__); 1857 return retval; 1858 } 1859 1860 if (freq_table[index].frequency == policy->cur) 1861 return 0; 1862 1863 return __target_index(policy, freq_table, index); 1864 } 1865 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1866 1867 int cpufreq_driver_target(struct cpufreq_policy *policy, 1868 unsigned int target_freq, 1869 unsigned int relation) 1870 { 1871 int ret = -EINVAL; 1872 1873 down_write(&policy->rwsem); 1874 1875 ret = __cpufreq_driver_target(policy, target_freq, relation); 1876 1877 up_write(&policy->rwsem); 1878 1879 return ret; 1880 } 1881 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1882 1883 __weak struct cpufreq_governor *cpufreq_fallback_governor(void) 1884 { 1885 return NULL; 1886 } 1887 1888 static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event) 1889 { 1890 int ret; 1891 1892 /* Don't start any governor operations if we are entering suspend */ 1893 if (cpufreq_suspended) 1894 return 0; 1895 /* 1896 * Governor might not be initiated here if ACPI _PPC changed 1897 * notification happened, so check it. 1898 */ 1899 if (!policy->governor) 1900 return -EINVAL; 1901 1902 if (policy->governor->max_transition_latency && 1903 policy->cpuinfo.transition_latency > 1904 policy->governor->max_transition_latency) { 1905 struct cpufreq_governor *gov = cpufreq_fallback_governor(); 1906 1907 if (gov) { 1908 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", 1909 policy->governor->name, gov->name); 1910 policy->governor = gov; 1911 } else { 1912 return -EINVAL; 1913 } 1914 } 1915 1916 if (event == CPUFREQ_GOV_POLICY_INIT) 1917 if (!try_module_get(policy->governor->owner)) 1918 return -EINVAL; 1919 1920 pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event); 1921 1922 ret = policy->governor->governor(policy, event); 1923 1924 if (!ret) { 1925 if (event == CPUFREQ_GOV_POLICY_INIT) 1926 policy->governor->initialized++; 1927 else if (event == CPUFREQ_GOV_POLICY_EXIT) 1928 policy->governor->initialized--; 1929 } 1930 1931 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || 1932 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) 1933 module_put(policy->governor->owner); 1934 1935 return ret; 1936 } 1937 1938 static int cpufreq_start_governor(struct cpufreq_policy *policy) 1939 { 1940 int ret; 1941 1942 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) 1943 cpufreq_update_current_freq(policy); 1944 1945 ret = cpufreq_governor(policy, CPUFREQ_GOV_START); 1946 return ret ? ret : cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 1947 } 1948 1949 int cpufreq_register_governor(struct cpufreq_governor *governor) 1950 { 1951 int err; 1952 1953 if (!governor) 1954 return -EINVAL; 1955 1956 if (cpufreq_disabled()) 1957 return -ENODEV; 1958 1959 mutex_lock(&cpufreq_governor_mutex); 1960 1961 governor->initialized = 0; 1962 err = -EBUSY; 1963 if (!find_governor(governor->name)) { 1964 err = 0; 1965 list_add(&governor->governor_list, &cpufreq_governor_list); 1966 } 1967 1968 mutex_unlock(&cpufreq_governor_mutex); 1969 return err; 1970 } 1971 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 1972 1973 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 1974 { 1975 struct cpufreq_policy *policy; 1976 unsigned long flags; 1977 1978 if (!governor) 1979 return; 1980 1981 if (cpufreq_disabled()) 1982 return; 1983 1984 /* clear last_governor for all inactive policies */ 1985 read_lock_irqsave(&cpufreq_driver_lock, flags); 1986 for_each_inactive_policy(policy) { 1987 if (!strcmp(policy->last_governor, governor->name)) { 1988 policy->governor = NULL; 1989 strcpy(policy->last_governor, "\0"); 1990 } 1991 } 1992 read_unlock_irqrestore(&cpufreq_driver_lock, flags); 1993 1994 mutex_lock(&cpufreq_governor_mutex); 1995 list_del(&governor->governor_list); 1996 mutex_unlock(&cpufreq_governor_mutex); 1997 return; 1998 } 1999 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 2000 2001 2002 /********************************************************************* 2003 * POLICY INTERFACE * 2004 *********************************************************************/ 2005 2006 /** 2007 * cpufreq_get_policy - get the current cpufreq_policy 2008 * @policy: struct cpufreq_policy into which the current cpufreq_policy 2009 * is written 2010 * 2011 * Reads the current cpufreq policy. 2012 */ 2013 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 2014 { 2015 struct cpufreq_policy *cpu_policy; 2016 if (!policy) 2017 return -EINVAL; 2018 2019 cpu_policy = cpufreq_cpu_get(cpu); 2020 if (!cpu_policy) 2021 return -EINVAL; 2022 2023 memcpy(policy, cpu_policy, sizeof(*policy)); 2024 2025 cpufreq_cpu_put(cpu_policy); 2026 return 0; 2027 } 2028 EXPORT_SYMBOL(cpufreq_get_policy); 2029 2030 /* 2031 * policy : current policy. 2032 * new_policy: policy to be set. 2033 */ 2034 static int cpufreq_set_policy(struct cpufreq_policy *policy, 2035 struct cpufreq_policy *new_policy) 2036 { 2037 struct cpufreq_governor *old_gov; 2038 int ret; 2039 2040 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", 2041 new_policy->cpu, new_policy->min, new_policy->max); 2042 2043 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); 2044 2045 /* 2046 * This check works well when we store new min/max freq attributes, 2047 * because new_policy is a copy of policy with one field updated. 2048 */ 2049 if (new_policy->min > new_policy->max) 2050 return -EINVAL; 2051 2052 /* verify the cpu speed can be set within this limit */ 2053 ret = cpufreq_driver->verify(new_policy); 2054 if (ret) 2055 return ret; 2056 2057 /* adjust if necessary - all reasons */ 2058 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2059 CPUFREQ_ADJUST, new_policy); 2060 2061 /* 2062 * verify the cpu speed can be set within this limit, which might be 2063 * different to the first one 2064 */ 2065 ret = cpufreq_driver->verify(new_policy); 2066 if (ret) 2067 return ret; 2068 2069 /* notification of the new policy */ 2070 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 2071 CPUFREQ_NOTIFY, new_policy); 2072 2073 policy->min = new_policy->min; 2074 policy->max = new_policy->max; 2075 2076 pr_debug("new min and max freqs are %u - %u kHz\n", 2077 policy->min, policy->max); 2078 2079 if (cpufreq_driver->setpolicy) { 2080 policy->policy = new_policy->policy; 2081 pr_debug("setting range\n"); 2082 return cpufreq_driver->setpolicy(new_policy); 2083 } 2084 2085 if (new_policy->governor == policy->governor) { 2086 pr_debug("cpufreq: governor limits update\n"); 2087 return cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2088 } 2089 2090 pr_debug("governor switch\n"); 2091 2092 /* save old, working values */ 2093 old_gov = policy->governor; 2094 /* end old governor */ 2095 if (old_gov) { 2096 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP); 2097 if (ret) { 2098 /* This can happen due to race with other operations */ 2099 pr_debug("%s: Failed to Stop Governor: %s (%d)\n", 2100 __func__, old_gov->name, ret); 2101 return ret; 2102 } 2103 2104 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2105 if (ret) { 2106 pr_err("%s: Failed to Exit Governor: %s (%d)\n", 2107 __func__, old_gov->name, ret); 2108 return ret; 2109 } 2110 } 2111 2112 /* start new governor */ 2113 policy->governor = new_policy->governor; 2114 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); 2115 if (!ret) { 2116 ret = cpufreq_start_governor(policy); 2117 if (!ret) { 2118 pr_debug("cpufreq: governor change\n"); 2119 return 0; 2120 } 2121 cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); 2122 } 2123 2124 /* new governor failed, so re-start old one */ 2125 pr_debug("starting governor %s failed\n", policy->governor->name); 2126 if (old_gov) { 2127 policy->governor = old_gov; 2128 if (cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) 2129 policy->governor = NULL; 2130 else 2131 cpufreq_start_governor(policy); 2132 } 2133 2134 return ret; 2135 } 2136 2137 /** 2138 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 2139 * @cpu: CPU which shall be re-evaluated 2140 * 2141 * Useful for policy notifiers which have different necessities 2142 * at different times. 2143 */ 2144 int cpufreq_update_policy(unsigned int cpu) 2145 { 2146 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 2147 struct cpufreq_policy new_policy; 2148 int ret; 2149 2150 if (!policy) 2151 return -ENODEV; 2152 2153 down_write(&policy->rwsem); 2154 2155 pr_debug("updating policy for CPU %u\n", cpu); 2156 memcpy(&new_policy, policy, sizeof(*policy)); 2157 new_policy.min = policy->user_policy.min; 2158 new_policy.max = policy->user_policy.max; 2159 2160 /* 2161 * BIOS might change freq behind our back 2162 * -> ask driver for current freq and notify governors about a change 2163 */ 2164 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { 2165 new_policy.cur = cpufreq_update_current_freq(policy); 2166 if (WARN_ON(!new_policy.cur)) { 2167 ret = -EIO; 2168 goto unlock; 2169 } 2170 } 2171 2172 ret = cpufreq_set_policy(policy, &new_policy); 2173 2174 unlock: 2175 up_write(&policy->rwsem); 2176 2177 cpufreq_cpu_put(policy); 2178 return ret; 2179 } 2180 EXPORT_SYMBOL(cpufreq_update_policy); 2181 2182 static int cpufreq_cpu_callback(struct notifier_block *nfb, 2183 unsigned long action, void *hcpu) 2184 { 2185 unsigned int cpu = (unsigned long)hcpu; 2186 2187 switch (action & ~CPU_TASKS_FROZEN) { 2188 case CPU_ONLINE: 2189 cpufreq_online(cpu); 2190 break; 2191 2192 case CPU_DOWN_PREPARE: 2193 cpufreq_offline(cpu); 2194 break; 2195 2196 case CPU_DOWN_FAILED: 2197 cpufreq_online(cpu); 2198 break; 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 for_each_active_policy(policy) { 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 2227 down_write(&policy->rwsem); 2228 policy->user_policy.max = policy->max; 2229 cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); 2230 up_write(&policy->rwsem); 2231 } 2232 } 2233 2234 return ret; 2235 } 2236 2237 int cpufreq_boost_trigger_state(int state) 2238 { 2239 unsigned long flags; 2240 int ret = 0; 2241 2242 if (cpufreq_driver->boost_enabled == state) 2243 return 0; 2244 2245 write_lock_irqsave(&cpufreq_driver_lock, flags); 2246 cpufreq_driver->boost_enabled = state; 2247 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2248 2249 ret = cpufreq_driver->set_boost(state); 2250 if (ret) { 2251 write_lock_irqsave(&cpufreq_driver_lock, flags); 2252 cpufreq_driver->boost_enabled = !state; 2253 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2254 2255 pr_err("%s: Cannot %s BOOST\n", 2256 __func__, state ? "enable" : "disable"); 2257 } 2258 2259 return ret; 2260 } 2261 2262 static bool cpufreq_boost_supported(void) 2263 { 2264 return likely(cpufreq_driver) && cpufreq_driver->set_boost; 2265 } 2266 2267 static int create_boost_sysfs_file(void) 2268 { 2269 int ret; 2270 2271 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr); 2272 if (ret) 2273 pr_err("%s: cannot register global BOOST sysfs file\n", 2274 __func__); 2275 2276 return ret; 2277 } 2278 2279 static void remove_boost_sysfs_file(void) 2280 { 2281 if (cpufreq_boost_supported()) 2282 sysfs_remove_file(cpufreq_global_kobject, &boost.attr); 2283 } 2284 2285 int cpufreq_enable_boost_support(void) 2286 { 2287 if (!cpufreq_driver) 2288 return -EINVAL; 2289 2290 if (cpufreq_boost_supported()) 2291 return 0; 2292 2293 cpufreq_driver->set_boost = cpufreq_boost_set_sw; 2294 2295 /* This will get removed on driver unregister */ 2296 return create_boost_sysfs_file(); 2297 } 2298 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support); 2299 2300 int cpufreq_boost_enabled(void) 2301 { 2302 return cpufreq_driver->boost_enabled; 2303 } 2304 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); 2305 2306 /********************************************************************* 2307 * REGISTER / UNREGISTER CPUFREQ DRIVER * 2308 *********************************************************************/ 2309 2310 /** 2311 * cpufreq_register_driver - register a CPU Frequency driver 2312 * @driver_data: A struct cpufreq_driver containing the values# 2313 * submitted by the CPU Frequency driver. 2314 * 2315 * Registers a CPU Frequency driver to this core code. This code 2316 * returns zero on success, -EEXIST when another driver got here first 2317 * (and isn't unregistered in the meantime). 2318 * 2319 */ 2320 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 2321 { 2322 unsigned long flags; 2323 int ret; 2324 2325 if (cpufreq_disabled()) 2326 return -ENODEV; 2327 2328 if (!driver_data || !driver_data->verify || !driver_data->init || 2329 !(driver_data->setpolicy || driver_data->target_index || 2330 driver_data->target) || 2331 (driver_data->setpolicy && (driver_data->target_index || 2332 driver_data->target)) || 2333 (!!driver_data->get_intermediate != !!driver_data->target_intermediate)) 2334 return -EINVAL; 2335 2336 pr_debug("trying to register driver %s\n", driver_data->name); 2337 2338 /* Protect against concurrent CPU online/offline. */ 2339 get_online_cpus(); 2340 2341 write_lock_irqsave(&cpufreq_driver_lock, flags); 2342 if (cpufreq_driver) { 2343 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2344 ret = -EEXIST; 2345 goto out; 2346 } 2347 cpufreq_driver = driver_data; 2348 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2349 2350 if (driver_data->setpolicy) 2351 driver_data->flags |= CPUFREQ_CONST_LOOPS; 2352 2353 if (cpufreq_boost_supported()) { 2354 ret = create_boost_sysfs_file(); 2355 if (ret) 2356 goto err_null_driver; 2357 } 2358 2359 ret = subsys_interface_register(&cpufreq_interface); 2360 if (ret) 2361 goto err_boost_unreg; 2362 2363 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) && 2364 list_empty(&cpufreq_policy_list)) { 2365 /* if all ->init() calls failed, unregister */ 2366 pr_debug("%s: No CPU initialized for driver %s\n", __func__, 2367 driver_data->name); 2368 goto err_if_unreg; 2369 } 2370 2371 register_hotcpu_notifier(&cpufreq_cpu_notifier); 2372 pr_debug("driver %s up and running\n", driver_data->name); 2373 2374 out: 2375 put_online_cpus(); 2376 return ret; 2377 2378 err_if_unreg: 2379 subsys_interface_unregister(&cpufreq_interface); 2380 err_boost_unreg: 2381 remove_boost_sysfs_file(); 2382 err_null_driver: 2383 write_lock_irqsave(&cpufreq_driver_lock, flags); 2384 cpufreq_driver = NULL; 2385 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2386 goto out; 2387 } 2388 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 2389 2390 /** 2391 * cpufreq_unregister_driver - unregister the current CPUFreq driver 2392 * 2393 * Unregister the current CPUFreq driver. Only call this if you have 2394 * the right to do so, i.e. if you have succeeded in initialising before! 2395 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 2396 * currently not initialised. 2397 */ 2398 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 2399 { 2400 unsigned long flags; 2401 2402 if (!cpufreq_driver || (driver != cpufreq_driver)) 2403 return -EINVAL; 2404 2405 pr_debug("unregistering driver %s\n", driver->name); 2406 2407 /* Protect against concurrent cpu hotplug */ 2408 get_online_cpus(); 2409 subsys_interface_unregister(&cpufreq_interface); 2410 remove_boost_sysfs_file(); 2411 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 2412 2413 write_lock_irqsave(&cpufreq_driver_lock, flags); 2414 2415 cpufreq_driver = NULL; 2416 2417 write_unlock_irqrestore(&cpufreq_driver_lock, flags); 2418 put_online_cpus(); 2419 2420 return 0; 2421 } 2422 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 2423 2424 /* 2425 * Stop cpufreq at shutdown to make sure it isn't holding any locks 2426 * or mutexes when secondary CPUs are halted. 2427 */ 2428 static struct syscore_ops cpufreq_syscore_ops = { 2429 .shutdown = cpufreq_suspend, 2430 }; 2431 2432 struct kobject *cpufreq_global_kobject; 2433 EXPORT_SYMBOL(cpufreq_global_kobject); 2434 2435 static int __init cpufreq_core_init(void) 2436 { 2437 if (cpufreq_disabled()) 2438 return -ENODEV; 2439 2440 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj); 2441 BUG_ON(!cpufreq_global_kobject); 2442 2443 register_syscore_ops(&cpufreq_syscore_ops); 2444 2445 return 0; 2446 } 2447 core_initcall(cpufreq_core_init); 2448