1 /* 2 * linux/drivers/cpufreq/cpufreq.c 3 * 4 * Copyright (C) 2001 Russell King 5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> 6 * 7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com> 8 * Added handling for CPU hotplug 9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com> 10 * Fix handling for CPU hotplug -- affected CPUs 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 * 16 */ 17 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/notifier.h> 22 #include <linux/cpufreq.h> 23 #include <linux/delay.h> 24 #include <linux/interrupt.h> 25 #include <linux/spinlock.h> 26 #include <linux/device.h> 27 #include <linux/slab.h> 28 #include <linux/cpu.h> 29 #include <linux/completion.h> 30 #include <linux/mutex.h> 31 32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \ 33 "cpufreq-core", msg) 34 35 /** 36 * The "cpufreq driver" - the arch- or hardware-dependent low 37 * level driver of CPUFreq support, and its spinlock. This lock 38 * also protects the cpufreq_cpu_data array. 39 */ 40 static struct cpufreq_driver *cpufreq_driver; 41 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); 42 #ifdef CONFIG_HOTPLUG_CPU 43 /* This one keeps track of the previously set governor of a removed CPU */ 44 static DEFINE_PER_CPU(struct cpufreq_governor *, cpufreq_cpu_governor); 45 #endif 46 static DEFINE_SPINLOCK(cpufreq_driver_lock); 47 48 /* 49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure 50 * all cpufreq/hotplug/workqueue/etc related lock issues. 51 * 52 * The rules for this semaphore: 53 * - Any routine that wants to read from the policy structure will 54 * do a down_read on this semaphore. 55 * - Any routine that will write to the policy structure and/or may take away 56 * the policy altogether (eg. CPU hotplug), will hold this lock in write 57 * mode before doing so. 58 * 59 * Additional rules: 60 * - All holders of the lock should check to make sure that the CPU they 61 * are concerned with are online after they get the lock. 62 * - Governor routines that can be called in cpufreq hotplug path should not 63 * take this sem as top level hotplug notifier handler takes this. 64 */ 65 static DEFINE_PER_CPU(int, policy_cpu); 66 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem); 67 68 #define lock_policy_rwsem(mode, cpu) \ 69 int lock_policy_rwsem_##mode \ 70 (int cpu) \ 71 { \ 72 int policy_cpu = per_cpu(policy_cpu, cpu); \ 73 BUG_ON(policy_cpu == -1); \ 74 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ 75 if (unlikely(!cpu_online(cpu))) { \ 76 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ 77 return -1; \ 78 } \ 79 \ 80 return 0; \ 81 } 82 83 lock_policy_rwsem(read, cpu); 84 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read); 85 86 lock_policy_rwsem(write, cpu); 87 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write); 88 89 void unlock_policy_rwsem_read(int cpu) 90 { 91 int policy_cpu = per_cpu(policy_cpu, cpu); 92 BUG_ON(policy_cpu == -1); 93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu)); 94 } 95 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read); 96 97 void unlock_policy_rwsem_write(int cpu) 98 { 99 int policy_cpu = per_cpu(policy_cpu, cpu); 100 BUG_ON(policy_cpu == -1); 101 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu)); 102 } 103 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write); 104 105 106 /* internal prototypes */ 107 static int __cpufreq_governor(struct cpufreq_policy *policy, 108 unsigned int event); 109 static unsigned int __cpufreq_get(unsigned int cpu); 110 static void handle_update(struct work_struct *work); 111 112 /** 113 * Two notifier lists: the "policy" list is involved in the 114 * validation process for a new CPU frequency policy; the 115 * "transition" list for kernel code that needs to handle 116 * changes to devices when the CPU clock speed changes. 117 * The mutex locks both lists. 118 */ 119 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); 120 static struct srcu_notifier_head cpufreq_transition_notifier_list; 121 122 static bool init_cpufreq_transition_notifier_list_called; 123 static int __init init_cpufreq_transition_notifier_list(void) 124 { 125 srcu_init_notifier_head(&cpufreq_transition_notifier_list); 126 init_cpufreq_transition_notifier_list_called = true; 127 return 0; 128 } 129 pure_initcall(init_cpufreq_transition_notifier_list); 130 131 static LIST_HEAD(cpufreq_governor_list); 132 static DEFINE_MUTEX(cpufreq_governor_mutex); 133 134 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) 135 { 136 struct cpufreq_policy *data; 137 unsigned long flags; 138 139 if (cpu >= nr_cpu_ids) 140 goto err_out; 141 142 /* get the cpufreq driver */ 143 spin_lock_irqsave(&cpufreq_driver_lock, flags); 144 145 if (!cpufreq_driver) 146 goto err_out_unlock; 147 148 if (!try_module_get(cpufreq_driver->owner)) 149 goto err_out_unlock; 150 151 152 /* get the CPU */ 153 data = per_cpu(cpufreq_cpu_data, cpu); 154 155 if (!data) 156 goto err_out_put_module; 157 158 if (!kobject_get(&data->kobj)) 159 goto err_out_put_module; 160 161 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 162 return data; 163 164 err_out_put_module: 165 module_put(cpufreq_driver->owner); 166 err_out_unlock: 167 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 168 err_out: 169 return NULL; 170 } 171 EXPORT_SYMBOL_GPL(cpufreq_cpu_get); 172 173 174 void cpufreq_cpu_put(struct cpufreq_policy *data) 175 { 176 kobject_put(&data->kobj); 177 module_put(cpufreq_driver->owner); 178 } 179 EXPORT_SYMBOL_GPL(cpufreq_cpu_put); 180 181 182 /********************************************************************* 183 * UNIFIED DEBUG HELPERS * 184 *********************************************************************/ 185 #ifdef CONFIG_CPU_FREQ_DEBUG 186 187 /* what part(s) of the CPUfreq subsystem are debugged? */ 188 static unsigned int debug; 189 190 /* is the debug output ratelimit'ed using printk_ratelimit? User can 191 * set or modify this value. 192 */ 193 static unsigned int debug_ratelimit = 1; 194 195 /* is the printk_ratelimit'ing enabled? It's enabled after a successful 196 * loading of a cpufreq driver, temporarily disabled when a new policy 197 * is set, and disabled upon cpufreq driver removal 198 */ 199 static unsigned int disable_ratelimit = 1; 200 static DEFINE_SPINLOCK(disable_ratelimit_lock); 201 202 static void cpufreq_debug_enable_ratelimit(void) 203 { 204 unsigned long flags; 205 206 spin_lock_irqsave(&disable_ratelimit_lock, flags); 207 if (disable_ratelimit) 208 disable_ratelimit--; 209 spin_unlock_irqrestore(&disable_ratelimit_lock, flags); 210 } 211 212 static void cpufreq_debug_disable_ratelimit(void) 213 { 214 unsigned long flags; 215 216 spin_lock_irqsave(&disable_ratelimit_lock, flags); 217 disable_ratelimit++; 218 spin_unlock_irqrestore(&disable_ratelimit_lock, flags); 219 } 220 221 void cpufreq_debug_printk(unsigned int type, const char *prefix, 222 const char *fmt, ...) 223 { 224 char s[256]; 225 va_list args; 226 unsigned int len; 227 unsigned long flags; 228 229 WARN_ON(!prefix); 230 if (type & debug) { 231 spin_lock_irqsave(&disable_ratelimit_lock, flags); 232 if (!disable_ratelimit && debug_ratelimit 233 && !printk_ratelimit()) { 234 spin_unlock_irqrestore(&disable_ratelimit_lock, flags); 235 return; 236 } 237 spin_unlock_irqrestore(&disable_ratelimit_lock, flags); 238 239 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix); 240 241 va_start(args, fmt); 242 len += vsnprintf(&s[len], (256 - len), fmt, args); 243 va_end(args); 244 245 printk(s); 246 247 WARN_ON(len < 5); 248 } 249 } 250 EXPORT_SYMBOL(cpufreq_debug_printk); 251 252 253 module_param(debug, uint, 0644); 254 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core," 255 " 2 to debug drivers, and 4 to debug governors."); 256 257 module_param(debug_ratelimit, uint, 0644); 258 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:" 259 " set to 0 to disable ratelimiting."); 260 261 #else /* !CONFIG_CPU_FREQ_DEBUG */ 262 263 static inline void cpufreq_debug_enable_ratelimit(void) { return; } 264 static inline void cpufreq_debug_disable_ratelimit(void) { return; } 265 266 #endif /* CONFIG_CPU_FREQ_DEBUG */ 267 268 269 /********************************************************************* 270 * EXTERNALLY AFFECTING FREQUENCY CHANGES * 271 *********************************************************************/ 272 273 /** 274 * adjust_jiffies - adjust the system "loops_per_jiffy" 275 * 276 * This function alters the system "loops_per_jiffy" for the clock 277 * speed change. Note that loops_per_jiffy cannot be updated on SMP 278 * systems as each CPU might be scaled differently. So, use the arch 279 * per-CPU loops_per_jiffy value wherever possible. 280 */ 281 #ifndef CONFIG_SMP 282 static unsigned long l_p_j_ref; 283 static unsigned int l_p_j_ref_freq; 284 285 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 286 { 287 if (ci->flags & CPUFREQ_CONST_LOOPS) 288 return; 289 290 if (!l_p_j_ref_freq) { 291 l_p_j_ref = loops_per_jiffy; 292 l_p_j_ref_freq = ci->old; 293 dprintk("saving %lu as reference value for loops_per_jiffy; " 294 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq); 295 } 296 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) || 297 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) || 298 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) { 299 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, 300 ci->new); 301 dprintk("scaling loops_per_jiffy to %lu " 302 "for frequency %u kHz\n", loops_per_jiffy, ci->new); 303 } 304 } 305 #else 306 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 307 { 308 return; 309 } 310 #endif 311 312 313 /** 314 * cpufreq_notify_transition - call notifier chain and adjust_jiffies 315 * on frequency transition. 316 * 317 * This function calls the transition notifiers and the "adjust_jiffies" 318 * function. It is called twice on all CPU frequency changes that have 319 * external effects. 320 */ 321 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) 322 { 323 struct cpufreq_policy *policy; 324 325 BUG_ON(irqs_disabled()); 326 327 freqs->flags = cpufreq_driver->flags; 328 dprintk("notification %u of frequency transition to %u kHz\n", 329 state, freqs->new); 330 331 policy = per_cpu(cpufreq_cpu_data, freqs->cpu); 332 switch (state) { 333 334 case CPUFREQ_PRECHANGE: 335 /* detect if the driver reported a value as "old frequency" 336 * which is not equal to what the cpufreq core thinks is 337 * "old frequency". 338 */ 339 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 340 if ((policy) && (policy->cpu == freqs->cpu) && 341 (policy->cur) && (policy->cur != freqs->old)) { 342 dprintk("Warning: CPU frequency is" 343 " %u, cpufreq assumed %u kHz.\n", 344 freqs->old, policy->cur); 345 freqs->old = policy->cur; 346 } 347 } 348 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 349 CPUFREQ_PRECHANGE, freqs); 350 adjust_jiffies(CPUFREQ_PRECHANGE, freqs); 351 break; 352 353 case CPUFREQ_POSTCHANGE: 354 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); 355 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 356 CPUFREQ_POSTCHANGE, freqs); 357 if (likely(policy) && likely(policy->cpu == freqs->cpu)) 358 policy->cur = freqs->new; 359 break; 360 } 361 } 362 EXPORT_SYMBOL_GPL(cpufreq_notify_transition); 363 364 365 366 /********************************************************************* 367 * SYSFS INTERFACE * 368 *********************************************************************/ 369 370 static struct cpufreq_governor *__find_governor(const char *str_governor) 371 { 372 struct cpufreq_governor *t; 373 374 list_for_each_entry(t, &cpufreq_governor_list, governor_list) 375 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN)) 376 return t; 377 378 return NULL; 379 } 380 381 /** 382 * cpufreq_parse_governor - parse a governor string 383 */ 384 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, 385 struct cpufreq_governor **governor) 386 { 387 int err = -EINVAL; 388 389 if (!cpufreq_driver) 390 goto out; 391 392 if (cpufreq_driver->setpolicy) { 393 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { 394 *policy = CPUFREQ_POLICY_PERFORMANCE; 395 err = 0; 396 } else if (!strnicmp(str_governor, "powersave", 397 CPUFREQ_NAME_LEN)) { 398 *policy = CPUFREQ_POLICY_POWERSAVE; 399 err = 0; 400 } 401 } else if (cpufreq_driver->target) { 402 struct cpufreq_governor *t; 403 404 mutex_lock(&cpufreq_governor_mutex); 405 406 t = __find_governor(str_governor); 407 408 if (t == NULL) { 409 char *name = kasprintf(GFP_KERNEL, "cpufreq_%s", 410 str_governor); 411 412 if (name) { 413 int ret; 414 415 mutex_unlock(&cpufreq_governor_mutex); 416 ret = request_module("%s", name); 417 mutex_lock(&cpufreq_governor_mutex); 418 419 if (ret == 0) 420 t = __find_governor(str_governor); 421 } 422 423 kfree(name); 424 } 425 426 if (t != NULL) { 427 *governor = t; 428 err = 0; 429 } 430 431 mutex_unlock(&cpufreq_governor_mutex); 432 } 433 out: 434 return err; 435 } 436 437 438 /** 439 * cpufreq_per_cpu_attr_read() / show_##file_name() - 440 * print out cpufreq information 441 * 442 * Write out information from cpufreq_driver->policy[cpu]; object must be 443 * "unsigned int". 444 */ 445 446 #define show_one(file_name, object) \ 447 static ssize_t show_##file_name \ 448 (struct cpufreq_policy *policy, char *buf) \ 449 { \ 450 return sprintf(buf, "%u\n", policy->object); \ 451 } 452 453 show_one(cpuinfo_min_freq, cpuinfo.min_freq); 454 show_one(cpuinfo_max_freq, cpuinfo.max_freq); 455 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); 456 show_one(scaling_min_freq, min); 457 show_one(scaling_max_freq, max); 458 show_one(scaling_cur_freq, cur); 459 460 static int __cpufreq_set_policy(struct cpufreq_policy *data, 461 struct cpufreq_policy *policy); 462 463 /** 464 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access 465 */ 466 #define store_one(file_name, object) \ 467 static ssize_t store_##file_name \ 468 (struct cpufreq_policy *policy, const char *buf, size_t count) \ 469 { \ 470 unsigned int ret = -EINVAL; \ 471 struct cpufreq_policy new_policy; \ 472 \ 473 ret = cpufreq_get_policy(&new_policy, policy->cpu); \ 474 if (ret) \ 475 return -EINVAL; \ 476 \ 477 ret = sscanf(buf, "%u", &new_policy.object); \ 478 if (ret != 1) \ 479 return -EINVAL; \ 480 \ 481 ret = __cpufreq_set_policy(policy, &new_policy); \ 482 policy->user_policy.object = policy->object; \ 483 \ 484 return ret ? ret : count; \ 485 } 486 487 store_one(scaling_min_freq, min); 488 store_one(scaling_max_freq, max); 489 490 /** 491 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware 492 */ 493 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy, 494 char *buf) 495 { 496 unsigned int cur_freq = __cpufreq_get(policy->cpu); 497 if (!cur_freq) 498 return sprintf(buf, "<unknown>"); 499 return sprintf(buf, "%u\n", cur_freq); 500 } 501 502 503 /** 504 * show_scaling_governor - show the current policy for the specified CPU 505 */ 506 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) 507 { 508 if (policy->policy == CPUFREQ_POLICY_POWERSAVE) 509 return sprintf(buf, "powersave\n"); 510 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) 511 return sprintf(buf, "performance\n"); 512 else if (policy->governor) 513 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", 514 policy->governor->name); 515 return -EINVAL; 516 } 517 518 519 /** 520 * store_scaling_governor - store policy for the specified CPU 521 */ 522 static ssize_t store_scaling_governor(struct cpufreq_policy *policy, 523 const char *buf, size_t count) 524 { 525 unsigned int ret = -EINVAL; 526 char str_governor[16]; 527 struct cpufreq_policy new_policy; 528 529 ret = cpufreq_get_policy(&new_policy, policy->cpu); 530 if (ret) 531 return ret; 532 533 ret = sscanf(buf, "%15s", str_governor); 534 if (ret != 1) 535 return -EINVAL; 536 537 if (cpufreq_parse_governor(str_governor, &new_policy.policy, 538 &new_policy.governor)) 539 return -EINVAL; 540 541 /* Do not use cpufreq_set_policy here or the user_policy.max 542 will be wrongly overridden */ 543 ret = __cpufreq_set_policy(policy, &new_policy); 544 545 policy->user_policy.policy = policy->policy; 546 policy->user_policy.governor = policy->governor; 547 548 if (ret) 549 return ret; 550 else 551 return count; 552 } 553 554 /** 555 * show_scaling_driver - show the cpufreq driver currently loaded 556 */ 557 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) 558 { 559 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name); 560 } 561 562 /** 563 * show_scaling_available_governors - show the available CPUfreq governors 564 */ 565 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, 566 char *buf) 567 { 568 ssize_t i = 0; 569 struct cpufreq_governor *t; 570 571 if (!cpufreq_driver->target) { 572 i += sprintf(buf, "performance powersave"); 573 goto out; 574 } 575 576 list_for_each_entry(t, &cpufreq_governor_list, governor_list) { 577 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) 578 - (CPUFREQ_NAME_LEN + 2))) 579 goto out; 580 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name); 581 } 582 out: 583 i += sprintf(&buf[i], "\n"); 584 return i; 585 } 586 587 static ssize_t show_cpus(const struct cpumask *mask, char *buf) 588 { 589 ssize_t i = 0; 590 unsigned int cpu; 591 592 for_each_cpu(cpu, mask) { 593 if (i) 594 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); 595 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); 596 if (i >= (PAGE_SIZE - 5)) 597 break; 598 } 599 i += sprintf(&buf[i], "\n"); 600 return i; 601 } 602 603 /** 604 * show_related_cpus - show the CPUs affected by each transition even if 605 * hw coordination is in use 606 */ 607 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf) 608 { 609 if (cpumask_empty(policy->related_cpus)) 610 return show_cpus(policy->cpus, buf); 611 return 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 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 #define define_one_ro(_name) \ 649 static struct freq_attr _name = \ 650 __ATTR(_name, 0444, show_##_name, NULL) 651 652 #define define_one_ro0400(_name) \ 653 static struct freq_attr _name = \ 654 __ATTR(_name, 0400, show_##_name, NULL) 655 656 #define define_one_rw(_name) \ 657 static struct freq_attr _name = \ 658 __ATTR(_name, 0644, show_##_name, store_##_name) 659 660 define_one_ro0400(cpuinfo_cur_freq); 661 define_one_ro(cpuinfo_min_freq); 662 define_one_ro(cpuinfo_max_freq); 663 define_one_ro(cpuinfo_transition_latency); 664 define_one_ro(scaling_available_governors); 665 define_one_ro(scaling_driver); 666 define_one_ro(scaling_cur_freq); 667 define_one_ro(related_cpus); 668 define_one_ro(affected_cpus); 669 define_one_rw(scaling_min_freq); 670 define_one_rw(scaling_max_freq); 671 define_one_rw(scaling_governor); 672 define_one_rw(scaling_setspeed); 673 674 static struct attribute *default_attrs[] = { 675 &cpuinfo_min_freq.attr, 676 &cpuinfo_max_freq.attr, 677 &cpuinfo_transition_latency.attr, 678 &scaling_min_freq.attr, 679 &scaling_max_freq.attr, 680 &affected_cpus.attr, 681 &related_cpus.attr, 682 &scaling_governor.attr, 683 &scaling_driver.attr, 684 &scaling_available_governors.attr, 685 &scaling_setspeed.attr, 686 NULL 687 }; 688 689 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj) 690 #define to_attr(a) container_of(a, struct freq_attr, attr) 691 692 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) 693 { 694 struct cpufreq_policy *policy = to_policy(kobj); 695 struct freq_attr *fattr = to_attr(attr); 696 ssize_t ret = -EINVAL; 697 policy = cpufreq_cpu_get(policy->cpu); 698 if (!policy) 699 goto no_policy; 700 701 if (lock_policy_rwsem_read(policy->cpu) < 0) 702 goto fail; 703 704 if (fattr->show) 705 ret = fattr->show(policy, buf); 706 else 707 ret = -EIO; 708 709 unlock_policy_rwsem_read(policy->cpu); 710 fail: 711 cpufreq_cpu_put(policy); 712 no_policy: 713 return ret; 714 } 715 716 static ssize_t store(struct kobject *kobj, struct attribute *attr, 717 const char *buf, size_t count) 718 { 719 struct cpufreq_policy *policy = to_policy(kobj); 720 struct freq_attr *fattr = to_attr(attr); 721 ssize_t ret = -EINVAL; 722 policy = cpufreq_cpu_get(policy->cpu); 723 if (!policy) 724 goto no_policy; 725 726 if (lock_policy_rwsem_write(policy->cpu) < 0) 727 goto fail; 728 729 if (fattr->store) 730 ret = fattr->store(policy, buf, count); 731 else 732 ret = -EIO; 733 734 unlock_policy_rwsem_write(policy->cpu); 735 fail: 736 cpufreq_cpu_put(policy); 737 no_policy: 738 return ret; 739 } 740 741 static void cpufreq_sysfs_release(struct kobject *kobj) 742 { 743 struct cpufreq_policy *policy = to_policy(kobj); 744 dprintk("last reference is dropped\n"); 745 complete(&policy->kobj_unregister); 746 } 747 748 static struct sysfs_ops sysfs_ops = { 749 .show = show, 750 .store = store, 751 }; 752 753 static struct kobj_type ktype_cpufreq = { 754 .sysfs_ops = &sysfs_ops, 755 .default_attrs = default_attrs, 756 .release = cpufreq_sysfs_release, 757 }; 758 759 760 /** 761 * cpufreq_add_dev - add a CPU device 762 * 763 * Adds the cpufreq interface for a CPU device. 764 * 765 * The Oracle says: try running cpufreq registration/unregistration concurrently 766 * with with cpu hotplugging and all hell will break loose. Tried to clean this 767 * mess up, but more thorough testing is needed. - Mathieu 768 */ 769 static int cpufreq_add_dev(struct sys_device *sys_dev) 770 { 771 unsigned int cpu = sys_dev->id; 772 int ret = 0; 773 struct cpufreq_policy new_policy; 774 struct cpufreq_policy *policy; 775 struct freq_attr **drv_attr; 776 struct sys_device *cpu_sys_dev; 777 unsigned long flags; 778 unsigned int j; 779 780 if (cpu_is_offline(cpu)) 781 return 0; 782 783 cpufreq_debug_disable_ratelimit(); 784 dprintk("adding CPU %u\n", cpu); 785 786 #ifdef CONFIG_SMP 787 /* check whether a different CPU already registered this 788 * CPU because it is in the same boat. */ 789 policy = cpufreq_cpu_get(cpu); 790 if (unlikely(policy)) { 791 cpufreq_cpu_put(policy); 792 cpufreq_debug_enable_ratelimit(); 793 return 0; 794 } 795 #endif 796 797 if (!try_module_get(cpufreq_driver->owner)) { 798 ret = -EINVAL; 799 goto module_out; 800 } 801 802 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); 803 if (!policy) { 804 ret = -ENOMEM; 805 goto nomem_out; 806 } 807 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) { 808 ret = -ENOMEM; 809 goto err_free_policy; 810 } 811 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) { 812 ret = -ENOMEM; 813 goto err_free_cpumask; 814 } 815 816 policy->cpu = cpu; 817 cpumask_copy(policy->cpus, cpumask_of(cpu)); 818 819 /* Initially set CPU itself as the policy_cpu */ 820 per_cpu(policy_cpu, cpu) = cpu; 821 ret = (lock_policy_rwsem_write(cpu) < 0); 822 WARN_ON(ret); 823 824 init_completion(&policy->kobj_unregister); 825 INIT_WORK(&policy->update, handle_update); 826 827 /* Set governor before ->init, so that driver could check it */ 828 policy->governor = CPUFREQ_DEFAULT_GOVERNOR; 829 /* call driver. From then on the cpufreq must be able 830 * to accept all calls to ->verify and ->setpolicy for this CPU 831 */ 832 ret = cpufreq_driver->init(policy); 833 if (ret) { 834 dprintk("initialization failed\n"); 835 goto err_unlock_policy; 836 } 837 policy->user_policy.min = policy->min; 838 policy->user_policy.max = policy->max; 839 840 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 841 CPUFREQ_START, policy); 842 843 #ifdef CONFIG_SMP 844 845 #ifdef CONFIG_HOTPLUG_CPU 846 if (per_cpu(cpufreq_cpu_governor, cpu)) { 847 policy->governor = per_cpu(cpufreq_cpu_governor, cpu); 848 dprintk("Restoring governor %s for cpu %d\n", 849 policy->governor->name, cpu); 850 } 851 #endif 852 853 for_each_cpu(j, policy->cpus) { 854 struct cpufreq_policy *managed_policy; 855 856 if (cpu == j) 857 continue; 858 859 /* Check for existing affected CPUs. 860 * They may not be aware of it due to CPU Hotplug. 861 */ 862 managed_policy = cpufreq_cpu_get(j); 863 if (unlikely(managed_policy)) { 864 865 /* Set proper policy_cpu */ 866 unlock_policy_rwsem_write(cpu); 867 per_cpu(policy_cpu, cpu) = managed_policy->cpu; 868 869 if (lock_policy_rwsem_write(cpu) < 0) { 870 /* Should not go through policy unlock path */ 871 if (cpufreq_driver->exit) 872 cpufreq_driver->exit(policy); 873 ret = -EBUSY; 874 cpufreq_cpu_put(managed_policy); 875 goto err_free_cpumask; 876 } 877 878 spin_lock_irqsave(&cpufreq_driver_lock, flags); 879 cpumask_copy(managed_policy->cpus, policy->cpus); 880 per_cpu(cpufreq_cpu_data, cpu) = managed_policy; 881 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 882 883 dprintk("CPU already managed, adding link\n"); 884 ret = sysfs_create_link(&sys_dev->kobj, 885 &managed_policy->kobj, 886 "cpufreq"); 887 if (!ret) 888 cpufreq_cpu_put(managed_policy); 889 /* 890 * Success. We only needed to be added to the mask. 891 * Call driver->exit() because only the cpu parent of 892 * the kobj needed to call init(). 893 */ 894 goto out_driver_exit; /* call driver->exit() */ 895 } 896 } 897 #endif 898 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); 899 900 /* prepare interface data */ 901 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj, 902 "cpufreq"); 903 if (ret) 904 goto out_driver_exit; 905 906 /* set up files for this cpu device */ 907 drv_attr = cpufreq_driver->attr; 908 while ((drv_attr) && (*drv_attr)) { 909 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); 910 if (ret) 911 goto err_out_kobj_put; 912 drv_attr++; 913 } 914 if (cpufreq_driver->get) { 915 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); 916 if (ret) 917 goto err_out_kobj_put; 918 } 919 if (cpufreq_driver->target) { 920 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); 921 if (ret) 922 goto err_out_kobj_put; 923 } 924 925 spin_lock_irqsave(&cpufreq_driver_lock, flags); 926 for_each_cpu(j, policy->cpus) { 927 per_cpu(cpufreq_cpu_data, j) = policy; 928 per_cpu(policy_cpu, j) = policy->cpu; 929 } 930 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 931 932 /* symlink affected CPUs */ 933 for_each_cpu(j, policy->cpus) { 934 struct cpufreq_policy *managed_policy; 935 936 if (j == cpu) 937 continue; 938 if (!cpu_online(j)) 939 continue; 940 941 dprintk("CPU %u already managed, adding link\n", j); 942 managed_policy = cpufreq_cpu_get(cpu); 943 cpu_sys_dev = get_cpu_sysdev(j); 944 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj, 945 "cpufreq"); 946 if (ret) { 947 cpufreq_cpu_put(managed_policy); 948 goto err_out_unregister; 949 } 950 } 951 952 policy->governor = NULL; /* to assure that the starting sequence is 953 * run in cpufreq_set_policy */ 954 955 /* set default policy */ 956 ret = __cpufreq_set_policy(policy, &new_policy); 957 policy->user_policy.policy = policy->policy; 958 policy->user_policy.governor = policy->governor; 959 960 if (ret) { 961 dprintk("setting policy failed\n"); 962 goto err_out_unregister; 963 } 964 965 unlock_policy_rwsem_write(cpu); 966 967 kobject_uevent(&policy->kobj, KOBJ_ADD); 968 module_put(cpufreq_driver->owner); 969 dprintk("initialization complete\n"); 970 cpufreq_debug_enable_ratelimit(); 971 972 return 0; 973 974 975 err_out_unregister: 976 spin_lock_irqsave(&cpufreq_driver_lock, flags); 977 for_each_cpu(j, policy->cpus) 978 per_cpu(cpufreq_cpu_data, j) = NULL; 979 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 980 981 err_out_kobj_put: 982 kobject_put(&policy->kobj); 983 wait_for_completion(&policy->kobj_unregister); 984 985 out_driver_exit: 986 if (cpufreq_driver->exit) 987 cpufreq_driver->exit(policy); 988 989 err_unlock_policy: 990 unlock_policy_rwsem_write(cpu); 991 err_free_cpumask: 992 free_cpumask_var(policy->cpus); 993 err_free_policy: 994 kfree(policy); 995 nomem_out: 996 module_put(cpufreq_driver->owner); 997 module_out: 998 cpufreq_debug_enable_ratelimit(); 999 return ret; 1000 } 1001 1002 1003 /** 1004 * __cpufreq_remove_dev - remove a CPU device 1005 * 1006 * Removes the cpufreq interface for a CPU device. 1007 * Caller should already have policy_rwsem in write mode for this CPU. 1008 * This routine frees the rwsem before returning. 1009 */ 1010 static int __cpufreq_remove_dev(struct sys_device *sys_dev) 1011 { 1012 unsigned int cpu = sys_dev->id; 1013 unsigned long flags; 1014 struct cpufreq_policy *data; 1015 #ifdef CONFIG_SMP 1016 struct sys_device *cpu_sys_dev; 1017 unsigned int j; 1018 #endif 1019 1020 cpufreq_debug_disable_ratelimit(); 1021 dprintk("unregistering CPU %u\n", cpu); 1022 1023 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1024 data = per_cpu(cpufreq_cpu_data, cpu); 1025 1026 if (!data) { 1027 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1028 cpufreq_debug_enable_ratelimit(); 1029 unlock_policy_rwsem_write(cpu); 1030 return -EINVAL; 1031 } 1032 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1033 1034 1035 #ifdef CONFIG_SMP 1036 /* if this isn't the CPU which is the parent of the kobj, we 1037 * only need to unlink, put and exit 1038 */ 1039 if (unlikely(cpu != data->cpu)) { 1040 dprintk("removing link\n"); 1041 cpumask_clear_cpu(cpu, data->cpus); 1042 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1043 sysfs_remove_link(&sys_dev->kobj, "cpufreq"); 1044 cpufreq_cpu_put(data); 1045 cpufreq_debug_enable_ratelimit(); 1046 unlock_policy_rwsem_write(cpu); 1047 return 0; 1048 } 1049 #endif 1050 1051 #ifdef CONFIG_SMP 1052 1053 #ifdef CONFIG_HOTPLUG_CPU 1054 per_cpu(cpufreq_cpu_governor, cpu) = data->governor; 1055 #endif 1056 1057 /* if we have other CPUs still registered, we need to unlink them, 1058 * or else wait_for_completion below will lock up. Clean the 1059 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove 1060 * the sysfs links afterwards. 1061 */ 1062 if (unlikely(cpumask_weight(data->cpus) > 1)) { 1063 for_each_cpu(j, data->cpus) { 1064 if (j == cpu) 1065 continue; 1066 per_cpu(cpufreq_cpu_data, j) = NULL; 1067 } 1068 } 1069 1070 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1071 1072 if (unlikely(cpumask_weight(data->cpus) > 1)) { 1073 for_each_cpu(j, data->cpus) { 1074 if (j == cpu) 1075 continue; 1076 dprintk("removing link for cpu %u\n", j); 1077 #ifdef CONFIG_HOTPLUG_CPU 1078 per_cpu(cpufreq_cpu_governor, j) = data->governor; 1079 #endif 1080 cpu_sys_dev = get_cpu_sysdev(j); 1081 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq"); 1082 cpufreq_cpu_put(data); 1083 } 1084 } 1085 #else 1086 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1087 #endif 1088 1089 if (cpufreq_driver->target) 1090 __cpufreq_governor(data, CPUFREQ_GOV_STOP); 1091 1092 kobject_put(&data->kobj); 1093 1094 /* we need to make sure that the underlying kobj is actually 1095 * not referenced anymore by anybody before we proceed with 1096 * unloading. 1097 */ 1098 dprintk("waiting for dropping of refcount\n"); 1099 wait_for_completion(&data->kobj_unregister); 1100 dprintk("wait complete\n"); 1101 1102 if (cpufreq_driver->exit) 1103 cpufreq_driver->exit(data); 1104 1105 unlock_policy_rwsem_write(cpu); 1106 1107 free_cpumask_var(data->related_cpus); 1108 free_cpumask_var(data->cpus); 1109 kfree(data); 1110 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1111 1112 cpufreq_debug_enable_ratelimit(); 1113 return 0; 1114 } 1115 1116 1117 static int cpufreq_remove_dev(struct sys_device *sys_dev) 1118 { 1119 unsigned int cpu = sys_dev->id; 1120 int retval; 1121 1122 if (cpu_is_offline(cpu)) 1123 return 0; 1124 1125 if (unlikely(lock_policy_rwsem_write(cpu))) 1126 BUG(); 1127 1128 retval = __cpufreq_remove_dev(sys_dev); 1129 return retval; 1130 } 1131 1132 1133 static void handle_update(struct work_struct *work) 1134 { 1135 struct cpufreq_policy *policy = 1136 container_of(work, struct cpufreq_policy, update); 1137 unsigned int cpu = policy->cpu; 1138 dprintk("handle_update for cpu %u called\n", cpu); 1139 cpufreq_update_policy(cpu); 1140 } 1141 1142 /** 1143 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble. 1144 * @cpu: cpu number 1145 * @old_freq: CPU frequency the kernel thinks the CPU runs at 1146 * @new_freq: CPU frequency the CPU actually runs at 1147 * 1148 * We adjust to current frequency first, and need to clean up later. 1149 * So either call to cpufreq_update_policy() or schedule handle_update()). 1150 */ 1151 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, 1152 unsigned int new_freq) 1153 { 1154 struct cpufreq_freqs freqs; 1155 1156 dprintk("Warning: CPU frequency out of sync: cpufreq and timing " 1157 "core thinks of %u, is %u kHz.\n", old_freq, new_freq); 1158 1159 freqs.cpu = cpu; 1160 freqs.old = old_freq; 1161 freqs.new = new_freq; 1162 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 1163 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 1164 } 1165 1166 1167 /** 1168 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1169 * @cpu: CPU number 1170 * 1171 * This is the last known freq, without actually getting it from the driver. 1172 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1173 */ 1174 unsigned int cpufreq_quick_get(unsigned int cpu) 1175 { 1176 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1177 unsigned int ret_freq = 0; 1178 1179 if (policy) { 1180 ret_freq = policy->cur; 1181 cpufreq_cpu_put(policy); 1182 } 1183 1184 return ret_freq; 1185 } 1186 EXPORT_SYMBOL(cpufreq_quick_get); 1187 1188 1189 static unsigned int __cpufreq_get(unsigned int cpu) 1190 { 1191 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1192 unsigned int ret_freq = 0; 1193 1194 if (!cpufreq_driver->get) 1195 return ret_freq; 1196 1197 ret_freq = cpufreq_driver->get(cpu); 1198 1199 if (ret_freq && policy->cur && 1200 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1201 /* verify no discrepancy between actual and 1202 saved value exists */ 1203 if (unlikely(ret_freq != policy->cur)) { 1204 cpufreq_out_of_sync(cpu, policy->cur, ret_freq); 1205 schedule_work(&policy->update); 1206 } 1207 } 1208 1209 return ret_freq; 1210 } 1211 1212 /** 1213 * cpufreq_get - get the current CPU frequency (in kHz) 1214 * @cpu: CPU number 1215 * 1216 * Get the CPU current (static) CPU frequency 1217 */ 1218 unsigned int cpufreq_get(unsigned int cpu) 1219 { 1220 unsigned int ret_freq = 0; 1221 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1222 1223 if (!policy) 1224 goto out; 1225 1226 if (unlikely(lock_policy_rwsem_read(cpu))) 1227 goto out_policy; 1228 1229 ret_freq = __cpufreq_get(cpu); 1230 1231 unlock_policy_rwsem_read(cpu); 1232 1233 out_policy: 1234 cpufreq_cpu_put(policy); 1235 out: 1236 return ret_freq; 1237 } 1238 EXPORT_SYMBOL(cpufreq_get); 1239 1240 1241 /** 1242 * cpufreq_suspend - let the low level driver prepare for suspend 1243 */ 1244 1245 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg) 1246 { 1247 int cpu = sysdev->id; 1248 int ret = 0; 1249 unsigned int cur_freq = 0; 1250 struct cpufreq_policy *cpu_policy; 1251 1252 dprintk("suspending cpu %u\n", cpu); 1253 1254 if (!cpu_online(cpu)) 1255 return 0; 1256 1257 /* we may be lax here as interrupts are off. Nonetheless 1258 * we need to grab the correct cpu policy, as to check 1259 * whether we really run on this CPU. 1260 */ 1261 1262 cpu_policy = cpufreq_cpu_get(cpu); 1263 if (!cpu_policy) 1264 return -EINVAL; 1265 1266 /* only handle each CPU group once */ 1267 if (unlikely(cpu_policy->cpu != cpu)) 1268 goto out; 1269 1270 if (cpufreq_driver->suspend) { 1271 ret = cpufreq_driver->suspend(cpu_policy, pmsg); 1272 if (ret) { 1273 printk(KERN_ERR "cpufreq: suspend failed in ->suspend " 1274 "step on CPU %u\n", cpu_policy->cpu); 1275 goto out; 1276 } 1277 } 1278 1279 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS) 1280 goto out; 1281 1282 if (cpufreq_driver->get) 1283 cur_freq = cpufreq_driver->get(cpu_policy->cpu); 1284 1285 if (!cur_freq || !cpu_policy->cur) { 1286 printk(KERN_ERR "cpufreq: suspend failed to assert current " 1287 "frequency is what timing core thinks it is.\n"); 1288 goto out; 1289 } 1290 1291 if (unlikely(cur_freq != cpu_policy->cur)) { 1292 struct cpufreq_freqs freqs; 1293 1294 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) 1295 dprintk("Warning: CPU frequency is %u, " 1296 "cpufreq assumed %u kHz.\n", 1297 cur_freq, cpu_policy->cur); 1298 1299 freqs.cpu = cpu; 1300 freqs.old = cpu_policy->cur; 1301 freqs.new = cur_freq; 1302 1303 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 1304 CPUFREQ_SUSPENDCHANGE, &freqs); 1305 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs); 1306 1307 cpu_policy->cur = cur_freq; 1308 } 1309 1310 out: 1311 cpufreq_cpu_put(cpu_policy); 1312 return ret; 1313 } 1314 1315 /** 1316 * cpufreq_resume - restore proper CPU frequency handling after resume 1317 * 1318 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume()) 1319 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync 1320 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are 1321 * restored. 1322 */ 1323 static int cpufreq_resume(struct sys_device *sysdev) 1324 { 1325 int cpu = sysdev->id; 1326 int ret = 0; 1327 struct cpufreq_policy *cpu_policy; 1328 1329 dprintk("resuming cpu %u\n", cpu); 1330 1331 if (!cpu_online(cpu)) 1332 return 0; 1333 1334 /* we may be lax here as interrupts are off. Nonetheless 1335 * we need to grab the correct cpu policy, as to check 1336 * whether we really run on this CPU. 1337 */ 1338 1339 cpu_policy = cpufreq_cpu_get(cpu); 1340 if (!cpu_policy) 1341 return -EINVAL; 1342 1343 /* only handle each CPU group once */ 1344 if (unlikely(cpu_policy->cpu != cpu)) 1345 goto fail; 1346 1347 if (cpufreq_driver->resume) { 1348 ret = cpufreq_driver->resume(cpu_policy); 1349 if (ret) { 1350 printk(KERN_ERR "cpufreq: resume failed in ->resume " 1351 "step on CPU %u\n", cpu_policy->cpu); 1352 goto fail; 1353 } 1354 } 1355 1356 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1357 unsigned int cur_freq = 0; 1358 1359 if (cpufreq_driver->get) 1360 cur_freq = cpufreq_driver->get(cpu_policy->cpu); 1361 1362 if (!cur_freq || !cpu_policy->cur) { 1363 printk(KERN_ERR "cpufreq: resume failed to assert " 1364 "current frequency is what timing core " 1365 "thinks it is.\n"); 1366 goto out; 1367 } 1368 1369 if (unlikely(cur_freq != cpu_policy->cur)) { 1370 struct cpufreq_freqs freqs; 1371 1372 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) 1373 dprintk("Warning: CPU frequency " 1374 "is %u, cpufreq assumed %u kHz.\n", 1375 cur_freq, cpu_policy->cur); 1376 1377 freqs.cpu = cpu; 1378 freqs.old = cpu_policy->cur; 1379 freqs.new = cur_freq; 1380 1381 srcu_notifier_call_chain( 1382 &cpufreq_transition_notifier_list, 1383 CPUFREQ_RESUMECHANGE, &freqs); 1384 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs); 1385 1386 cpu_policy->cur = cur_freq; 1387 } 1388 } 1389 1390 out: 1391 schedule_work(&cpu_policy->update); 1392 fail: 1393 cpufreq_cpu_put(cpu_policy); 1394 return ret; 1395 } 1396 1397 static struct sysdev_driver cpufreq_sysdev_driver = { 1398 .add = cpufreq_add_dev, 1399 .remove = cpufreq_remove_dev, 1400 .suspend = cpufreq_suspend, 1401 .resume = cpufreq_resume, 1402 }; 1403 1404 1405 /********************************************************************* 1406 * NOTIFIER LISTS INTERFACE * 1407 *********************************************************************/ 1408 1409 /** 1410 * cpufreq_register_notifier - register a driver with cpufreq 1411 * @nb: notifier function to register 1412 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1413 * 1414 * Add a driver to one of two lists: either a list of drivers that 1415 * are notified about clock rate changes (once before and once after 1416 * the transition), or a list of drivers that are notified about 1417 * changes in cpufreq policy. 1418 * 1419 * This function may sleep, and has the same return conditions as 1420 * blocking_notifier_chain_register. 1421 */ 1422 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1423 { 1424 int ret; 1425 1426 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1427 1428 switch (list) { 1429 case CPUFREQ_TRANSITION_NOTIFIER: 1430 ret = srcu_notifier_chain_register( 1431 &cpufreq_transition_notifier_list, nb); 1432 break; 1433 case CPUFREQ_POLICY_NOTIFIER: 1434 ret = blocking_notifier_chain_register( 1435 &cpufreq_policy_notifier_list, nb); 1436 break; 1437 default: 1438 ret = -EINVAL; 1439 } 1440 1441 return ret; 1442 } 1443 EXPORT_SYMBOL(cpufreq_register_notifier); 1444 1445 1446 /** 1447 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1448 * @nb: notifier block to be unregistered 1449 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1450 * 1451 * Remove a driver from the CPU frequency notifier list. 1452 * 1453 * This function may sleep, and has the same return conditions as 1454 * blocking_notifier_chain_unregister. 1455 */ 1456 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1457 { 1458 int ret; 1459 1460 switch (list) { 1461 case CPUFREQ_TRANSITION_NOTIFIER: 1462 ret = srcu_notifier_chain_unregister( 1463 &cpufreq_transition_notifier_list, nb); 1464 break; 1465 case CPUFREQ_POLICY_NOTIFIER: 1466 ret = blocking_notifier_chain_unregister( 1467 &cpufreq_policy_notifier_list, nb); 1468 break; 1469 default: 1470 ret = -EINVAL; 1471 } 1472 1473 return ret; 1474 } 1475 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1476 1477 1478 /********************************************************************* 1479 * GOVERNORS * 1480 *********************************************************************/ 1481 1482 1483 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1484 unsigned int target_freq, 1485 unsigned int relation) 1486 { 1487 int retval = -EINVAL; 1488 1489 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu, 1490 target_freq, relation); 1491 if (cpu_online(policy->cpu) && cpufreq_driver->target) 1492 retval = cpufreq_driver->target(policy, target_freq, relation); 1493 1494 return retval; 1495 } 1496 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1497 1498 int cpufreq_driver_target(struct cpufreq_policy *policy, 1499 unsigned int target_freq, 1500 unsigned int relation) 1501 { 1502 int ret = -EINVAL; 1503 1504 policy = cpufreq_cpu_get(policy->cpu); 1505 if (!policy) 1506 goto no_policy; 1507 1508 if (unlikely(lock_policy_rwsem_write(policy->cpu))) 1509 goto fail; 1510 1511 ret = __cpufreq_driver_target(policy, target_freq, relation); 1512 1513 unlock_policy_rwsem_write(policy->cpu); 1514 1515 fail: 1516 cpufreq_cpu_put(policy); 1517 no_policy: 1518 return ret; 1519 } 1520 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1521 1522 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu) 1523 { 1524 int ret = 0; 1525 1526 policy = cpufreq_cpu_get(policy->cpu); 1527 if (!policy) 1528 return -EINVAL; 1529 1530 if (cpu_online(cpu) && cpufreq_driver->getavg) 1531 ret = cpufreq_driver->getavg(policy, cpu); 1532 1533 cpufreq_cpu_put(policy); 1534 return ret; 1535 } 1536 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg); 1537 1538 /* 1539 * when "event" is CPUFREQ_GOV_LIMITS 1540 */ 1541 1542 static int __cpufreq_governor(struct cpufreq_policy *policy, 1543 unsigned int event) 1544 { 1545 int ret; 1546 1547 /* Only must be defined when default governor is known to have latency 1548 restrictions, like e.g. conservative or ondemand. 1549 That this is the case is already ensured in Kconfig 1550 */ 1551 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE 1552 struct cpufreq_governor *gov = &cpufreq_gov_performance; 1553 #else 1554 struct cpufreq_governor *gov = NULL; 1555 #endif 1556 1557 if (policy->governor->max_transition_latency && 1558 policy->cpuinfo.transition_latency > 1559 policy->governor->max_transition_latency) { 1560 if (!gov) 1561 return -EINVAL; 1562 else { 1563 printk(KERN_WARNING "%s governor failed, too long" 1564 " transition latency of HW, fallback" 1565 " to %s governor\n", 1566 policy->governor->name, 1567 gov->name); 1568 policy->governor = gov; 1569 } 1570 } 1571 1572 if (!try_module_get(policy->governor->owner)) 1573 return -EINVAL; 1574 1575 dprintk("__cpufreq_governor for CPU %u, event %u\n", 1576 policy->cpu, event); 1577 ret = policy->governor->governor(policy, event); 1578 1579 /* we keep one module reference alive for 1580 each CPU governed by this CPU */ 1581 if ((event != CPUFREQ_GOV_START) || ret) 1582 module_put(policy->governor->owner); 1583 if ((event == CPUFREQ_GOV_STOP) && !ret) 1584 module_put(policy->governor->owner); 1585 1586 return ret; 1587 } 1588 1589 1590 int cpufreq_register_governor(struct cpufreq_governor *governor) 1591 { 1592 int err; 1593 1594 if (!governor) 1595 return -EINVAL; 1596 1597 mutex_lock(&cpufreq_governor_mutex); 1598 1599 err = -EBUSY; 1600 if (__find_governor(governor->name) == NULL) { 1601 err = 0; 1602 list_add(&governor->governor_list, &cpufreq_governor_list); 1603 } 1604 1605 mutex_unlock(&cpufreq_governor_mutex); 1606 return err; 1607 } 1608 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 1609 1610 1611 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 1612 { 1613 if (!governor) 1614 return; 1615 1616 mutex_lock(&cpufreq_governor_mutex); 1617 list_del(&governor->governor_list); 1618 mutex_unlock(&cpufreq_governor_mutex); 1619 return; 1620 } 1621 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 1622 1623 1624 1625 /********************************************************************* 1626 * POLICY INTERFACE * 1627 *********************************************************************/ 1628 1629 /** 1630 * cpufreq_get_policy - get the current cpufreq_policy 1631 * @policy: struct cpufreq_policy into which the current cpufreq_policy 1632 * is written 1633 * 1634 * Reads the current cpufreq policy. 1635 */ 1636 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 1637 { 1638 struct cpufreq_policy *cpu_policy; 1639 if (!policy) 1640 return -EINVAL; 1641 1642 cpu_policy = cpufreq_cpu_get(cpu); 1643 if (!cpu_policy) 1644 return -EINVAL; 1645 1646 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); 1647 1648 cpufreq_cpu_put(cpu_policy); 1649 return 0; 1650 } 1651 EXPORT_SYMBOL(cpufreq_get_policy); 1652 1653 1654 /* 1655 * data : current policy. 1656 * policy : policy to be set. 1657 */ 1658 static int __cpufreq_set_policy(struct cpufreq_policy *data, 1659 struct cpufreq_policy *policy) 1660 { 1661 int ret = 0; 1662 1663 cpufreq_debug_disable_ratelimit(); 1664 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu, 1665 policy->min, policy->max); 1666 1667 memcpy(&policy->cpuinfo, &data->cpuinfo, 1668 sizeof(struct cpufreq_cpuinfo)); 1669 1670 if (policy->min > data->max || policy->max < data->min) { 1671 ret = -EINVAL; 1672 goto error_out; 1673 } 1674 1675 /* verify the cpu speed can be set within this limit */ 1676 ret = cpufreq_driver->verify(policy); 1677 if (ret) 1678 goto error_out; 1679 1680 /* adjust if necessary - all reasons */ 1681 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1682 CPUFREQ_ADJUST, policy); 1683 1684 /* adjust if necessary - hardware incompatibility*/ 1685 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1686 CPUFREQ_INCOMPATIBLE, policy); 1687 1688 /* verify the cpu speed can be set within this limit, 1689 which might be different to the first one */ 1690 ret = cpufreq_driver->verify(policy); 1691 if (ret) 1692 goto error_out; 1693 1694 /* notification of the new policy */ 1695 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1696 CPUFREQ_NOTIFY, policy); 1697 1698 data->min = policy->min; 1699 data->max = policy->max; 1700 1701 dprintk("new min and max freqs are %u - %u kHz\n", 1702 data->min, data->max); 1703 1704 if (cpufreq_driver->setpolicy) { 1705 data->policy = policy->policy; 1706 dprintk("setting range\n"); 1707 ret = cpufreq_driver->setpolicy(policy); 1708 } else { 1709 if (policy->governor != data->governor) { 1710 /* save old, working values */ 1711 struct cpufreq_governor *old_gov = data->governor; 1712 1713 dprintk("governor switch\n"); 1714 1715 /* end old governor */ 1716 if (data->governor) 1717 __cpufreq_governor(data, CPUFREQ_GOV_STOP); 1718 1719 /* start new governor */ 1720 data->governor = policy->governor; 1721 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) { 1722 /* new governor failed, so re-start old one */ 1723 dprintk("starting governor %s failed\n", 1724 data->governor->name); 1725 if (old_gov) { 1726 data->governor = old_gov; 1727 __cpufreq_governor(data, 1728 CPUFREQ_GOV_START); 1729 } 1730 ret = -EINVAL; 1731 goto error_out; 1732 } 1733 /* might be a policy change, too, so fall through */ 1734 } 1735 dprintk("governor: change or update limits\n"); 1736 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); 1737 } 1738 1739 error_out: 1740 cpufreq_debug_enable_ratelimit(); 1741 return ret; 1742 } 1743 1744 /** 1745 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 1746 * @cpu: CPU which shall be re-evaluated 1747 * 1748 * Usefull for policy notifiers which have different necessities 1749 * at different times. 1750 */ 1751 int cpufreq_update_policy(unsigned int cpu) 1752 { 1753 struct cpufreq_policy *data = cpufreq_cpu_get(cpu); 1754 struct cpufreq_policy policy; 1755 int ret; 1756 1757 if (!data) { 1758 ret = -ENODEV; 1759 goto no_policy; 1760 } 1761 1762 if (unlikely(lock_policy_rwsem_write(cpu))) { 1763 ret = -EINVAL; 1764 goto fail; 1765 } 1766 1767 dprintk("updating policy for CPU %u\n", cpu); 1768 memcpy(&policy, data, sizeof(struct cpufreq_policy)); 1769 policy.min = data->user_policy.min; 1770 policy.max = data->user_policy.max; 1771 policy.policy = data->user_policy.policy; 1772 policy.governor = data->user_policy.governor; 1773 1774 /* BIOS might change freq behind our back 1775 -> ask driver for current freq and notify governors about a change */ 1776 if (cpufreq_driver->get) { 1777 policy.cur = cpufreq_driver->get(cpu); 1778 if (!data->cur) { 1779 dprintk("Driver did not initialize current freq"); 1780 data->cur = policy.cur; 1781 } else { 1782 if (data->cur != policy.cur) 1783 cpufreq_out_of_sync(cpu, data->cur, 1784 policy.cur); 1785 } 1786 } 1787 1788 ret = __cpufreq_set_policy(data, &policy); 1789 1790 unlock_policy_rwsem_write(cpu); 1791 1792 fail: 1793 cpufreq_cpu_put(data); 1794 no_policy: 1795 return ret; 1796 } 1797 EXPORT_SYMBOL(cpufreq_update_policy); 1798 1799 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb, 1800 unsigned long action, void *hcpu) 1801 { 1802 unsigned int cpu = (unsigned long)hcpu; 1803 struct sys_device *sys_dev; 1804 1805 sys_dev = get_cpu_sysdev(cpu); 1806 if (sys_dev) { 1807 switch (action) { 1808 case CPU_ONLINE: 1809 case CPU_ONLINE_FROZEN: 1810 cpufreq_add_dev(sys_dev); 1811 break; 1812 case CPU_DOWN_PREPARE: 1813 case CPU_DOWN_PREPARE_FROZEN: 1814 if (unlikely(lock_policy_rwsem_write(cpu))) 1815 BUG(); 1816 1817 __cpufreq_remove_dev(sys_dev); 1818 break; 1819 case CPU_DOWN_FAILED: 1820 case CPU_DOWN_FAILED_FROZEN: 1821 cpufreq_add_dev(sys_dev); 1822 break; 1823 } 1824 } 1825 return NOTIFY_OK; 1826 } 1827 1828 static struct notifier_block __refdata cpufreq_cpu_notifier = 1829 { 1830 .notifier_call = cpufreq_cpu_callback, 1831 }; 1832 1833 /********************************************************************* 1834 * REGISTER / UNREGISTER CPUFREQ DRIVER * 1835 *********************************************************************/ 1836 1837 /** 1838 * cpufreq_register_driver - register a CPU Frequency driver 1839 * @driver_data: A struct cpufreq_driver containing the values# 1840 * submitted by the CPU Frequency driver. 1841 * 1842 * Registers a CPU Frequency driver to this core code. This code 1843 * returns zero on success, -EBUSY when another driver got here first 1844 * (and isn't unregistered in the meantime). 1845 * 1846 */ 1847 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 1848 { 1849 unsigned long flags; 1850 int ret; 1851 1852 if (!driver_data || !driver_data->verify || !driver_data->init || 1853 ((!driver_data->setpolicy) && (!driver_data->target))) 1854 return -EINVAL; 1855 1856 dprintk("trying to register driver %s\n", driver_data->name); 1857 1858 if (driver_data->setpolicy) 1859 driver_data->flags |= CPUFREQ_CONST_LOOPS; 1860 1861 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1862 if (cpufreq_driver) { 1863 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1864 return -EBUSY; 1865 } 1866 cpufreq_driver = driver_data; 1867 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1868 1869 ret = sysdev_driver_register(&cpu_sysdev_class, 1870 &cpufreq_sysdev_driver); 1871 1872 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) { 1873 int i; 1874 ret = -ENODEV; 1875 1876 /* check for at least one working CPU */ 1877 for (i = 0; i < nr_cpu_ids; i++) 1878 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { 1879 ret = 0; 1880 break; 1881 } 1882 1883 /* if all ->init() calls failed, unregister */ 1884 if (ret) { 1885 dprintk("no CPU initialized for driver %s\n", 1886 driver_data->name); 1887 sysdev_driver_unregister(&cpu_sysdev_class, 1888 &cpufreq_sysdev_driver); 1889 1890 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1891 cpufreq_driver = NULL; 1892 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1893 } 1894 } 1895 1896 if (!ret) { 1897 register_hotcpu_notifier(&cpufreq_cpu_notifier); 1898 dprintk("driver %s up and running\n", driver_data->name); 1899 cpufreq_debug_enable_ratelimit(); 1900 } 1901 1902 return ret; 1903 } 1904 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 1905 1906 1907 /** 1908 * cpufreq_unregister_driver - unregister the current CPUFreq driver 1909 * 1910 * Unregister the current CPUFreq driver. Only call this if you have 1911 * the right to do so, i.e. if you have succeeded in initialising before! 1912 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 1913 * currently not initialised. 1914 */ 1915 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 1916 { 1917 unsigned long flags; 1918 1919 cpufreq_debug_disable_ratelimit(); 1920 1921 if (!cpufreq_driver || (driver != cpufreq_driver)) { 1922 cpufreq_debug_enable_ratelimit(); 1923 return -EINVAL; 1924 } 1925 1926 dprintk("unregistering driver %s\n", driver->name); 1927 1928 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver); 1929 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 1930 1931 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1932 cpufreq_driver = NULL; 1933 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1934 1935 return 0; 1936 } 1937 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 1938 1939 static int __init cpufreq_core_init(void) 1940 { 1941 int cpu; 1942 1943 for_each_possible_cpu(cpu) { 1944 per_cpu(policy_cpu, cpu) = -1; 1945 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); 1946 } 1947 return 0; 1948 } 1949 1950 core_initcall(cpufreq_core_init); 1951