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 * cpufreq_cpu_put is called when the device is removed 862 * in __cpufreq_remove_dev() 863 */ 864 managed_policy = cpufreq_cpu_get(j); 865 if (unlikely(managed_policy)) { 866 867 /* Set proper policy_cpu */ 868 unlock_policy_rwsem_write(cpu); 869 per_cpu(policy_cpu, cpu) = managed_policy->cpu; 870 871 if (lock_policy_rwsem_write(cpu) < 0) { 872 /* Should not go through policy unlock path */ 873 if (cpufreq_driver->exit) 874 cpufreq_driver->exit(policy); 875 ret = -EBUSY; 876 cpufreq_cpu_put(managed_policy); 877 goto err_free_cpumask; 878 } 879 880 spin_lock_irqsave(&cpufreq_driver_lock, flags); 881 cpumask_copy(managed_policy->cpus, policy->cpus); 882 per_cpu(cpufreq_cpu_data, cpu) = managed_policy; 883 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 884 885 dprintk("CPU already managed, adding link\n"); 886 ret = sysfs_create_link(&sys_dev->kobj, 887 &managed_policy->kobj, 888 "cpufreq"); 889 if (ret) 890 cpufreq_cpu_put(managed_policy); 891 /* 892 * Success. We only needed to be added to the mask. 893 * Call driver->exit() because only the cpu parent of 894 * the kobj needed to call init(). 895 */ 896 goto out_driver_exit; /* call driver->exit() */ 897 } 898 } 899 #endif 900 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); 901 902 /* prepare interface data */ 903 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj, 904 "cpufreq"); 905 if (ret) 906 goto out_driver_exit; 907 908 /* set up files for this cpu device */ 909 drv_attr = cpufreq_driver->attr; 910 while ((drv_attr) && (*drv_attr)) { 911 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); 912 if (ret) 913 goto err_out_kobj_put; 914 drv_attr++; 915 } 916 if (cpufreq_driver->get) { 917 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); 918 if (ret) 919 goto err_out_kobj_put; 920 } 921 if (cpufreq_driver->target) { 922 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); 923 if (ret) 924 goto err_out_kobj_put; 925 } 926 927 spin_lock_irqsave(&cpufreq_driver_lock, flags); 928 for_each_cpu(j, policy->cpus) { 929 if (!cpu_online(j)) 930 continue; 931 per_cpu(cpufreq_cpu_data, j) = policy; 932 per_cpu(policy_cpu, j) = policy->cpu; 933 } 934 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 935 936 /* symlink affected CPUs */ 937 for_each_cpu(j, policy->cpus) { 938 struct cpufreq_policy *managed_policy; 939 940 if (j == cpu) 941 continue; 942 if (!cpu_online(j)) 943 continue; 944 945 dprintk("CPU %u already managed, adding link\n", j); 946 managed_policy = cpufreq_cpu_get(cpu); 947 cpu_sys_dev = get_cpu_sysdev(j); 948 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj, 949 "cpufreq"); 950 if (ret) { 951 cpufreq_cpu_put(managed_policy); 952 goto err_out_unregister; 953 } 954 } 955 956 policy->governor = NULL; /* to assure that the starting sequence is 957 * run in cpufreq_set_policy */ 958 959 /* set default policy */ 960 ret = __cpufreq_set_policy(policy, &new_policy); 961 policy->user_policy.policy = policy->policy; 962 policy->user_policy.governor = policy->governor; 963 964 if (ret) { 965 dprintk("setting policy failed\n"); 966 goto err_out_unregister; 967 } 968 969 unlock_policy_rwsem_write(cpu); 970 971 kobject_uevent(&policy->kobj, KOBJ_ADD); 972 module_put(cpufreq_driver->owner); 973 dprintk("initialization complete\n"); 974 cpufreq_debug_enable_ratelimit(); 975 976 return 0; 977 978 979 err_out_unregister: 980 spin_lock_irqsave(&cpufreq_driver_lock, flags); 981 for_each_cpu(j, policy->cpus) 982 per_cpu(cpufreq_cpu_data, j) = NULL; 983 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 984 985 err_out_kobj_put: 986 kobject_put(&policy->kobj); 987 wait_for_completion(&policy->kobj_unregister); 988 989 out_driver_exit: 990 if (cpufreq_driver->exit) 991 cpufreq_driver->exit(policy); 992 993 err_unlock_policy: 994 unlock_policy_rwsem_write(cpu); 995 err_free_cpumask: 996 free_cpumask_var(policy->cpus); 997 err_free_policy: 998 kfree(policy); 999 nomem_out: 1000 module_put(cpufreq_driver->owner); 1001 module_out: 1002 cpufreq_debug_enable_ratelimit(); 1003 return ret; 1004 } 1005 1006 1007 /** 1008 * __cpufreq_remove_dev - remove a CPU device 1009 * 1010 * Removes the cpufreq interface for a CPU device. 1011 * Caller should already have policy_rwsem in write mode for this CPU. 1012 * This routine frees the rwsem before returning. 1013 */ 1014 static int __cpufreq_remove_dev(struct sys_device *sys_dev) 1015 { 1016 unsigned int cpu = sys_dev->id; 1017 unsigned long flags; 1018 struct cpufreq_policy *data; 1019 #ifdef CONFIG_SMP 1020 struct sys_device *cpu_sys_dev; 1021 unsigned int j; 1022 #endif 1023 1024 cpufreq_debug_disable_ratelimit(); 1025 dprintk("unregistering CPU %u\n", cpu); 1026 1027 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1028 data = per_cpu(cpufreq_cpu_data, cpu); 1029 1030 if (!data) { 1031 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1032 cpufreq_debug_enable_ratelimit(); 1033 unlock_policy_rwsem_write(cpu); 1034 return -EINVAL; 1035 } 1036 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1037 1038 1039 #ifdef CONFIG_SMP 1040 /* if this isn't the CPU which is the parent of the kobj, we 1041 * only need to unlink, put and exit 1042 */ 1043 if (unlikely(cpu != data->cpu)) { 1044 dprintk("removing link\n"); 1045 cpumask_clear_cpu(cpu, data->cpus); 1046 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1047 sysfs_remove_link(&sys_dev->kobj, "cpufreq"); 1048 cpufreq_cpu_put(data); 1049 cpufreq_debug_enable_ratelimit(); 1050 unlock_policy_rwsem_write(cpu); 1051 return 0; 1052 } 1053 #endif 1054 1055 #ifdef CONFIG_SMP 1056 1057 #ifdef CONFIG_HOTPLUG_CPU 1058 per_cpu(cpufreq_cpu_governor, cpu) = data->governor; 1059 #endif 1060 1061 /* if we have other CPUs still registered, we need to unlink them, 1062 * or else wait_for_completion below will lock up. Clean the 1063 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove 1064 * the sysfs links afterwards. 1065 */ 1066 if (unlikely(cpumask_weight(data->cpus) > 1)) { 1067 for_each_cpu(j, data->cpus) { 1068 if (j == cpu) 1069 continue; 1070 per_cpu(cpufreq_cpu_data, j) = NULL; 1071 } 1072 } 1073 1074 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1075 1076 if (unlikely(cpumask_weight(data->cpus) > 1)) { 1077 for_each_cpu(j, data->cpus) { 1078 if (j == cpu) 1079 continue; 1080 dprintk("removing link for cpu %u\n", j); 1081 #ifdef CONFIG_HOTPLUG_CPU 1082 per_cpu(cpufreq_cpu_governor, j) = data->governor; 1083 #endif 1084 cpu_sys_dev = get_cpu_sysdev(j); 1085 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq"); 1086 cpufreq_cpu_put(data); 1087 } 1088 } 1089 #else 1090 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1091 #endif 1092 1093 if (cpufreq_driver->target) 1094 __cpufreq_governor(data, CPUFREQ_GOV_STOP); 1095 1096 kobject_put(&data->kobj); 1097 1098 /* we need to make sure that the underlying kobj is actually 1099 * not referenced anymore by anybody before we proceed with 1100 * unloading. 1101 */ 1102 dprintk("waiting for dropping of refcount\n"); 1103 wait_for_completion(&data->kobj_unregister); 1104 dprintk("wait complete\n"); 1105 1106 if (cpufreq_driver->exit) 1107 cpufreq_driver->exit(data); 1108 1109 unlock_policy_rwsem_write(cpu); 1110 1111 free_cpumask_var(data->related_cpus); 1112 free_cpumask_var(data->cpus); 1113 kfree(data); 1114 per_cpu(cpufreq_cpu_data, cpu) = NULL; 1115 1116 cpufreq_debug_enable_ratelimit(); 1117 return 0; 1118 } 1119 1120 1121 static int cpufreq_remove_dev(struct sys_device *sys_dev) 1122 { 1123 unsigned int cpu = sys_dev->id; 1124 int retval; 1125 1126 if (cpu_is_offline(cpu)) 1127 return 0; 1128 1129 if (unlikely(lock_policy_rwsem_write(cpu))) 1130 BUG(); 1131 1132 retval = __cpufreq_remove_dev(sys_dev); 1133 return retval; 1134 } 1135 1136 1137 static void handle_update(struct work_struct *work) 1138 { 1139 struct cpufreq_policy *policy = 1140 container_of(work, struct cpufreq_policy, update); 1141 unsigned int cpu = policy->cpu; 1142 dprintk("handle_update for cpu %u called\n", cpu); 1143 cpufreq_update_policy(cpu); 1144 } 1145 1146 /** 1147 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble. 1148 * @cpu: cpu number 1149 * @old_freq: CPU frequency the kernel thinks the CPU runs at 1150 * @new_freq: CPU frequency the CPU actually runs at 1151 * 1152 * We adjust to current frequency first, and need to clean up later. 1153 * So either call to cpufreq_update_policy() or schedule handle_update()). 1154 */ 1155 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, 1156 unsigned int new_freq) 1157 { 1158 struct cpufreq_freqs freqs; 1159 1160 dprintk("Warning: CPU frequency out of sync: cpufreq and timing " 1161 "core thinks of %u, is %u kHz.\n", old_freq, new_freq); 1162 1163 freqs.cpu = cpu; 1164 freqs.old = old_freq; 1165 freqs.new = new_freq; 1166 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 1167 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 1168 } 1169 1170 1171 /** 1172 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur 1173 * @cpu: CPU number 1174 * 1175 * This is the last known freq, without actually getting it from the driver. 1176 * Return value will be same as what is shown in scaling_cur_freq in sysfs. 1177 */ 1178 unsigned int cpufreq_quick_get(unsigned int cpu) 1179 { 1180 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1181 unsigned int ret_freq = 0; 1182 1183 if (policy) { 1184 ret_freq = policy->cur; 1185 cpufreq_cpu_put(policy); 1186 } 1187 1188 return ret_freq; 1189 } 1190 EXPORT_SYMBOL(cpufreq_quick_get); 1191 1192 1193 static unsigned int __cpufreq_get(unsigned int cpu) 1194 { 1195 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); 1196 unsigned int ret_freq = 0; 1197 1198 if (!cpufreq_driver->get) 1199 return ret_freq; 1200 1201 ret_freq = cpufreq_driver->get(cpu); 1202 1203 if (ret_freq && policy->cur && 1204 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1205 /* verify no discrepancy between actual and 1206 saved value exists */ 1207 if (unlikely(ret_freq != policy->cur)) { 1208 cpufreq_out_of_sync(cpu, policy->cur, ret_freq); 1209 schedule_work(&policy->update); 1210 } 1211 } 1212 1213 return ret_freq; 1214 } 1215 1216 /** 1217 * cpufreq_get - get the current CPU frequency (in kHz) 1218 * @cpu: CPU number 1219 * 1220 * Get the CPU current (static) CPU frequency 1221 */ 1222 unsigned int cpufreq_get(unsigned int cpu) 1223 { 1224 unsigned int ret_freq = 0; 1225 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 1226 1227 if (!policy) 1228 goto out; 1229 1230 if (unlikely(lock_policy_rwsem_read(cpu))) 1231 goto out_policy; 1232 1233 ret_freq = __cpufreq_get(cpu); 1234 1235 unlock_policy_rwsem_read(cpu); 1236 1237 out_policy: 1238 cpufreq_cpu_put(policy); 1239 out: 1240 return ret_freq; 1241 } 1242 EXPORT_SYMBOL(cpufreq_get); 1243 1244 1245 /** 1246 * cpufreq_suspend - let the low level driver prepare for suspend 1247 */ 1248 1249 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg) 1250 { 1251 int ret = 0; 1252 1253 #ifdef __powerpc__ 1254 int cpu = sysdev->id; 1255 unsigned int cur_freq = 0; 1256 struct cpufreq_policy *cpu_policy; 1257 1258 dprintk("suspending cpu %u\n", cpu); 1259 1260 /* 1261 * This whole bogosity is here because Powerbooks are made of fail. 1262 * No sane platform should need any of the code below to be run. 1263 * (it's entirely the wrong thing to do, as driver->get may 1264 * reenable interrupts on some architectures). 1265 */ 1266 1267 if (!cpu_online(cpu)) 1268 return 0; 1269 1270 /* we may be lax here as interrupts are off. Nonetheless 1271 * we need to grab the correct cpu policy, as to check 1272 * whether we really run on this CPU. 1273 */ 1274 1275 cpu_policy = cpufreq_cpu_get(cpu); 1276 if (!cpu_policy) 1277 return -EINVAL; 1278 1279 /* only handle each CPU group once */ 1280 if (unlikely(cpu_policy->cpu != cpu)) 1281 goto out; 1282 1283 if (cpufreq_driver->suspend) { 1284 ret = cpufreq_driver->suspend(cpu_policy, pmsg); 1285 if (ret) { 1286 printk(KERN_ERR "cpufreq: suspend failed in ->suspend " 1287 "step on CPU %u\n", cpu_policy->cpu); 1288 goto out; 1289 } 1290 } 1291 1292 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS) 1293 goto out; 1294 1295 if (cpufreq_driver->get) 1296 cur_freq = cpufreq_driver->get(cpu_policy->cpu); 1297 1298 if (!cur_freq || !cpu_policy->cur) { 1299 printk(KERN_ERR "cpufreq: suspend failed to assert current " 1300 "frequency is what timing core thinks it is.\n"); 1301 goto out; 1302 } 1303 1304 if (unlikely(cur_freq != cpu_policy->cur)) { 1305 struct cpufreq_freqs freqs; 1306 1307 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) 1308 dprintk("Warning: CPU frequency is %u, " 1309 "cpufreq assumed %u kHz.\n", 1310 cur_freq, cpu_policy->cur); 1311 1312 freqs.cpu = cpu; 1313 freqs.old = cpu_policy->cur; 1314 freqs.new = cur_freq; 1315 1316 srcu_notifier_call_chain(&cpufreq_transition_notifier_list, 1317 CPUFREQ_SUSPENDCHANGE, &freqs); 1318 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs); 1319 1320 cpu_policy->cur = cur_freq; 1321 } 1322 1323 out: 1324 cpufreq_cpu_put(cpu_policy); 1325 #endif /* __powerpc__ */ 1326 return ret; 1327 } 1328 1329 /** 1330 * cpufreq_resume - restore proper CPU frequency handling after resume 1331 * 1332 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume()) 1333 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync 1334 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are 1335 * restored. 1336 */ 1337 static int cpufreq_resume(struct sys_device *sysdev) 1338 { 1339 int ret = 0; 1340 1341 #ifdef __powerpc__ 1342 int cpu = sysdev->id; 1343 struct cpufreq_policy *cpu_policy; 1344 1345 dprintk("resuming cpu %u\n", cpu); 1346 1347 /* As with the ->suspend method, all the code below is 1348 * only necessary because Powerbooks suck. 1349 * See commit 42d4dc3f4e1e for jokes. */ 1350 1351 if (!cpu_online(cpu)) 1352 return 0; 1353 1354 /* we may be lax here as interrupts are off. Nonetheless 1355 * we need to grab the correct cpu policy, as to check 1356 * whether we really run on this CPU. 1357 */ 1358 1359 cpu_policy = cpufreq_cpu_get(cpu); 1360 if (!cpu_policy) 1361 return -EINVAL; 1362 1363 /* only handle each CPU group once */ 1364 if (unlikely(cpu_policy->cpu != cpu)) 1365 goto fail; 1366 1367 if (cpufreq_driver->resume) { 1368 ret = cpufreq_driver->resume(cpu_policy); 1369 if (ret) { 1370 printk(KERN_ERR "cpufreq: resume failed in ->resume " 1371 "step on CPU %u\n", cpu_policy->cpu); 1372 goto fail; 1373 } 1374 } 1375 1376 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { 1377 unsigned int cur_freq = 0; 1378 1379 if (cpufreq_driver->get) 1380 cur_freq = cpufreq_driver->get(cpu_policy->cpu); 1381 1382 if (!cur_freq || !cpu_policy->cur) { 1383 printk(KERN_ERR "cpufreq: resume failed to assert " 1384 "current frequency is what timing core " 1385 "thinks it is.\n"); 1386 goto out; 1387 } 1388 1389 if (unlikely(cur_freq != cpu_policy->cur)) { 1390 struct cpufreq_freqs freqs; 1391 1392 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN)) 1393 dprintk("Warning: CPU frequency " 1394 "is %u, cpufreq assumed %u kHz.\n", 1395 cur_freq, cpu_policy->cur); 1396 1397 freqs.cpu = cpu; 1398 freqs.old = cpu_policy->cur; 1399 freqs.new = cur_freq; 1400 1401 srcu_notifier_call_chain( 1402 &cpufreq_transition_notifier_list, 1403 CPUFREQ_RESUMECHANGE, &freqs); 1404 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs); 1405 1406 cpu_policy->cur = cur_freq; 1407 } 1408 } 1409 1410 out: 1411 schedule_work(&cpu_policy->update); 1412 fail: 1413 cpufreq_cpu_put(cpu_policy); 1414 #endif /* __powerpc__ */ 1415 return ret; 1416 } 1417 1418 static struct sysdev_driver cpufreq_sysdev_driver = { 1419 .add = cpufreq_add_dev, 1420 .remove = cpufreq_remove_dev, 1421 .suspend = cpufreq_suspend, 1422 .resume = cpufreq_resume, 1423 }; 1424 1425 1426 /********************************************************************* 1427 * NOTIFIER LISTS INTERFACE * 1428 *********************************************************************/ 1429 1430 /** 1431 * cpufreq_register_notifier - register a driver with cpufreq 1432 * @nb: notifier function to register 1433 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1434 * 1435 * Add a driver to one of two lists: either a list of drivers that 1436 * are notified about clock rate changes (once before and once after 1437 * the transition), or a list of drivers that are notified about 1438 * changes in cpufreq policy. 1439 * 1440 * This function may sleep, and has the same return conditions as 1441 * blocking_notifier_chain_register. 1442 */ 1443 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list) 1444 { 1445 int ret; 1446 1447 WARN_ON(!init_cpufreq_transition_notifier_list_called); 1448 1449 switch (list) { 1450 case CPUFREQ_TRANSITION_NOTIFIER: 1451 ret = srcu_notifier_chain_register( 1452 &cpufreq_transition_notifier_list, nb); 1453 break; 1454 case CPUFREQ_POLICY_NOTIFIER: 1455 ret = blocking_notifier_chain_register( 1456 &cpufreq_policy_notifier_list, nb); 1457 break; 1458 default: 1459 ret = -EINVAL; 1460 } 1461 1462 return ret; 1463 } 1464 EXPORT_SYMBOL(cpufreq_register_notifier); 1465 1466 1467 /** 1468 * cpufreq_unregister_notifier - unregister a driver with cpufreq 1469 * @nb: notifier block to be unregistered 1470 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER 1471 * 1472 * Remove a driver from the CPU frequency notifier list. 1473 * 1474 * This function may sleep, and has the same return conditions as 1475 * blocking_notifier_chain_unregister. 1476 */ 1477 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list) 1478 { 1479 int ret; 1480 1481 switch (list) { 1482 case CPUFREQ_TRANSITION_NOTIFIER: 1483 ret = srcu_notifier_chain_unregister( 1484 &cpufreq_transition_notifier_list, nb); 1485 break; 1486 case CPUFREQ_POLICY_NOTIFIER: 1487 ret = blocking_notifier_chain_unregister( 1488 &cpufreq_policy_notifier_list, nb); 1489 break; 1490 default: 1491 ret = -EINVAL; 1492 } 1493 1494 return ret; 1495 } 1496 EXPORT_SYMBOL(cpufreq_unregister_notifier); 1497 1498 1499 /********************************************************************* 1500 * GOVERNORS * 1501 *********************************************************************/ 1502 1503 1504 int __cpufreq_driver_target(struct cpufreq_policy *policy, 1505 unsigned int target_freq, 1506 unsigned int relation) 1507 { 1508 int retval = -EINVAL; 1509 1510 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu, 1511 target_freq, relation); 1512 if (cpu_online(policy->cpu) && cpufreq_driver->target) 1513 retval = cpufreq_driver->target(policy, target_freq, relation); 1514 1515 return retval; 1516 } 1517 EXPORT_SYMBOL_GPL(__cpufreq_driver_target); 1518 1519 int cpufreq_driver_target(struct cpufreq_policy *policy, 1520 unsigned int target_freq, 1521 unsigned int relation) 1522 { 1523 int ret = -EINVAL; 1524 1525 policy = cpufreq_cpu_get(policy->cpu); 1526 if (!policy) 1527 goto no_policy; 1528 1529 if (unlikely(lock_policy_rwsem_write(policy->cpu))) 1530 goto fail; 1531 1532 ret = __cpufreq_driver_target(policy, target_freq, relation); 1533 1534 unlock_policy_rwsem_write(policy->cpu); 1535 1536 fail: 1537 cpufreq_cpu_put(policy); 1538 no_policy: 1539 return ret; 1540 } 1541 EXPORT_SYMBOL_GPL(cpufreq_driver_target); 1542 1543 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu) 1544 { 1545 int ret = 0; 1546 1547 policy = cpufreq_cpu_get(policy->cpu); 1548 if (!policy) 1549 return -EINVAL; 1550 1551 if (cpu_online(cpu) && cpufreq_driver->getavg) 1552 ret = cpufreq_driver->getavg(policy, cpu); 1553 1554 cpufreq_cpu_put(policy); 1555 return ret; 1556 } 1557 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg); 1558 1559 /* 1560 * when "event" is CPUFREQ_GOV_LIMITS 1561 */ 1562 1563 static int __cpufreq_governor(struct cpufreq_policy *policy, 1564 unsigned int event) 1565 { 1566 int ret; 1567 1568 /* Only must be defined when default governor is known to have latency 1569 restrictions, like e.g. conservative or ondemand. 1570 That this is the case is already ensured in Kconfig 1571 */ 1572 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE 1573 struct cpufreq_governor *gov = &cpufreq_gov_performance; 1574 #else 1575 struct cpufreq_governor *gov = NULL; 1576 #endif 1577 1578 if (policy->governor->max_transition_latency && 1579 policy->cpuinfo.transition_latency > 1580 policy->governor->max_transition_latency) { 1581 if (!gov) 1582 return -EINVAL; 1583 else { 1584 printk(KERN_WARNING "%s governor failed, too long" 1585 " transition latency of HW, fallback" 1586 " to %s governor\n", 1587 policy->governor->name, 1588 gov->name); 1589 policy->governor = gov; 1590 } 1591 } 1592 1593 if (!try_module_get(policy->governor->owner)) 1594 return -EINVAL; 1595 1596 dprintk("__cpufreq_governor for CPU %u, event %u\n", 1597 policy->cpu, event); 1598 ret = policy->governor->governor(policy, event); 1599 1600 /* we keep one module reference alive for 1601 each CPU governed by this CPU */ 1602 if ((event != CPUFREQ_GOV_START) || ret) 1603 module_put(policy->governor->owner); 1604 if ((event == CPUFREQ_GOV_STOP) && !ret) 1605 module_put(policy->governor->owner); 1606 1607 return ret; 1608 } 1609 1610 1611 int cpufreq_register_governor(struct cpufreq_governor *governor) 1612 { 1613 int err; 1614 1615 if (!governor) 1616 return -EINVAL; 1617 1618 mutex_lock(&cpufreq_governor_mutex); 1619 1620 err = -EBUSY; 1621 if (__find_governor(governor->name) == NULL) { 1622 err = 0; 1623 list_add(&governor->governor_list, &cpufreq_governor_list); 1624 } 1625 1626 mutex_unlock(&cpufreq_governor_mutex); 1627 return err; 1628 } 1629 EXPORT_SYMBOL_GPL(cpufreq_register_governor); 1630 1631 1632 void cpufreq_unregister_governor(struct cpufreq_governor *governor) 1633 { 1634 if (!governor) 1635 return; 1636 1637 mutex_lock(&cpufreq_governor_mutex); 1638 list_del(&governor->governor_list); 1639 mutex_unlock(&cpufreq_governor_mutex); 1640 return; 1641 } 1642 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor); 1643 1644 1645 1646 /********************************************************************* 1647 * POLICY INTERFACE * 1648 *********************************************************************/ 1649 1650 /** 1651 * cpufreq_get_policy - get the current cpufreq_policy 1652 * @policy: struct cpufreq_policy into which the current cpufreq_policy 1653 * is written 1654 * 1655 * Reads the current cpufreq policy. 1656 */ 1657 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) 1658 { 1659 struct cpufreq_policy *cpu_policy; 1660 if (!policy) 1661 return -EINVAL; 1662 1663 cpu_policy = cpufreq_cpu_get(cpu); 1664 if (!cpu_policy) 1665 return -EINVAL; 1666 1667 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); 1668 1669 cpufreq_cpu_put(cpu_policy); 1670 return 0; 1671 } 1672 EXPORT_SYMBOL(cpufreq_get_policy); 1673 1674 1675 /* 1676 * data : current policy. 1677 * policy : policy to be set. 1678 */ 1679 static int __cpufreq_set_policy(struct cpufreq_policy *data, 1680 struct cpufreq_policy *policy) 1681 { 1682 int ret = 0; 1683 1684 cpufreq_debug_disable_ratelimit(); 1685 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu, 1686 policy->min, policy->max); 1687 1688 memcpy(&policy->cpuinfo, &data->cpuinfo, 1689 sizeof(struct cpufreq_cpuinfo)); 1690 1691 if (policy->min > data->max || policy->max < data->min) { 1692 ret = -EINVAL; 1693 goto error_out; 1694 } 1695 1696 /* verify the cpu speed can be set within this limit */ 1697 ret = cpufreq_driver->verify(policy); 1698 if (ret) 1699 goto error_out; 1700 1701 /* adjust if necessary - all reasons */ 1702 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1703 CPUFREQ_ADJUST, policy); 1704 1705 /* adjust if necessary - hardware incompatibility*/ 1706 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1707 CPUFREQ_INCOMPATIBLE, policy); 1708 1709 /* verify the cpu speed can be set within this limit, 1710 which might be different to the first one */ 1711 ret = cpufreq_driver->verify(policy); 1712 if (ret) 1713 goto error_out; 1714 1715 /* notification of the new policy */ 1716 blocking_notifier_call_chain(&cpufreq_policy_notifier_list, 1717 CPUFREQ_NOTIFY, policy); 1718 1719 data->min = policy->min; 1720 data->max = policy->max; 1721 1722 dprintk("new min and max freqs are %u - %u kHz\n", 1723 data->min, data->max); 1724 1725 if (cpufreq_driver->setpolicy) { 1726 data->policy = policy->policy; 1727 dprintk("setting range\n"); 1728 ret = cpufreq_driver->setpolicy(policy); 1729 } else { 1730 if (policy->governor != data->governor) { 1731 /* save old, working values */ 1732 struct cpufreq_governor *old_gov = data->governor; 1733 1734 dprintk("governor switch\n"); 1735 1736 /* end old governor */ 1737 if (data->governor) 1738 __cpufreq_governor(data, CPUFREQ_GOV_STOP); 1739 1740 /* start new governor */ 1741 data->governor = policy->governor; 1742 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) { 1743 /* new governor failed, so re-start old one */ 1744 dprintk("starting governor %s failed\n", 1745 data->governor->name); 1746 if (old_gov) { 1747 data->governor = old_gov; 1748 __cpufreq_governor(data, 1749 CPUFREQ_GOV_START); 1750 } 1751 ret = -EINVAL; 1752 goto error_out; 1753 } 1754 /* might be a policy change, too, so fall through */ 1755 } 1756 dprintk("governor: change or update limits\n"); 1757 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); 1758 } 1759 1760 error_out: 1761 cpufreq_debug_enable_ratelimit(); 1762 return ret; 1763 } 1764 1765 /** 1766 * cpufreq_update_policy - re-evaluate an existing cpufreq policy 1767 * @cpu: CPU which shall be re-evaluated 1768 * 1769 * Usefull for policy notifiers which have different necessities 1770 * at different times. 1771 */ 1772 int cpufreq_update_policy(unsigned int cpu) 1773 { 1774 struct cpufreq_policy *data = cpufreq_cpu_get(cpu); 1775 struct cpufreq_policy policy; 1776 int ret; 1777 1778 if (!data) { 1779 ret = -ENODEV; 1780 goto no_policy; 1781 } 1782 1783 if (unlikely(lock_policy_rwsem_write(cpu))) { 1784 ret = -EINVAL; 1785 goto fail; 1786 } 1787 1788 dprintk("updating policy for CPU %u\n", cpu); 1789 memcpy(&policy, data, sizeof(struct cpufreq_policy)); 1790 policy.min = data->user_policy.min; 1791 policy.max = data->user_policy.max; 1792 policy.policy = data->user_policy.policy; 1793 policy.governor = data->user_policy.governor; 1794 1795 /* BIOS might change freq behind our back 1796 -> ask driver for current freq and notify governors about a change */ 1797 if (cpufreq_driver->get) { 1798 policy.cur = cpufreq_driver->get(cpu); 1799 if (!data->cur) { 1800 dprintk("Driver did not initialize current freq"); 1801 data->cur = policy.cur; 1802 } else { 1803 if (data->cur != policy.cur) 1804 cpufreq_out_of_sync(cpu, data->cur, 1805 policy.cur); 1806 } 1807 } 1808 1809 ret = __cpufreq_set_policy(data, &policy); 1810 1811 unlock_policy_rwsem_write(cpu); 1812 1813 fail: 1814 cpufreq_cpu_put(data); 1815 no_policy: 1816 return ret; 1817 } 1818 EXPORT_SYMBOL(cpufreq_update_policy); 1819 1820 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb, 1821 unsigned long action, void *hcpu) 1822 { 1823 unsigned int cpu = (unsigned long)hcpu; 1824 struct sys_device *sys_dev; 1825 1826 sys_dev = get_cpu_sysdev(cpu); 1827 if (sys_dev) { 1828 switch (action) { 1829 case CPU_ONLINE: 1830 case CPU_ONLINE_FROZEN: 1831 cpufreq_add_dev(sys_dev); 1832 break; 1833 case CPU_DOWN_PREPARE: 1834 case CPU_DOWN_PREPARE_FROZEN: 1835 if (unlikely(lock_policy_rwsem_write(cpu))) 1836 BUG(); 1837 1838 __cpufreq_remove_dev(sys_dev); 1839 break; 1840 case CPU_DOWN_FAILED: 1841 case CPU_DOWN_FAILED_FROZEN: 1842 cpufreq_add_dev(sys_dev); 1843 break; 1844 } 1845 } 1846 return NOTIFY_OK; 1847 } 1848 1849 static struct notifier_block __refdata cpufreq_cpu_notifier = 1850 { 1851 .notifier_call = cpufreq_cpu_callback, 1852 }; 1853 1854 /********************************************************************* 1855 * REGISTER / UNREGISTER CPUFREQ DRIVER * 1856 *********************************************************************/ 1857 1858 /** 1859 * cpufreq_register_driver - register a CPU Frequency driver 1860 * @driver_data: A struct cpufreq_driver containing the values# 1861 * submitted by the CPU Frequency driver. 1862 * 1863 * Registers a CPU Frequency driver to this core code. This code 1864 * returns zero on success, -EBUSY when another driver got here first 1865 * (and isn't unregistered in the meantime). 1866 * 1867 */ 1868 int cpufreq_register_driver(struct cpufreq_driver *driver_data) 1869 { 1870 unsigned long flags; 1871 int ret; 1872 1873 if (!driver_data || !driver_data->verify || !driver_data->init || 1874 ((!driver_data->setpolicy) && (!driver_data->target))) 1875 return -EINVAL; 1876 1877 dprintk("trying to register driver %s\n", driver_data->name); 1878 1879 if (driver_data->setpolicy) 1880 driver_data->flags |= CPUFREQ_CONST_LOOPS; 1881 1882 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1883 if (cpufreq_driver) { 1884 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1885 return -EBUSY; 1886 } 1887 cpufreq_driver = driver_data; 1888 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1889 1890 ret = sysdev_driver_register(&cpu_sysdev_class, 1891 &cpufreq_sysdev_driver); 1892 1893 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) { 1894 int i; 1895 ret = -ENODEV; 1896 1897 /* check for at least one working CPU */ 1898 for (i = 0; i < nr_cpu_ids; i++) 1899 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) { 1900 ret = 0; 1901 break; 1902 } 1903 1904 /* if all ->init() calls failed, unregister */ 1905 if (ret) { 1906 dprintk("no CPU initialized for driver %s\n", 1907 driver_data->name); 1908 sysdev_driver_unregister(&cpu_sysdev_class, 1909 &cpufreq_sysdev_driver); 1910 1911 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1912 cpufreq_driver = NULL; 1913 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1914 } 1915 } 1916 1917 if (!ret) { 1918 register_hotcpu_notifier(&cpufreq_cpu_notifier); 1919 dprintk("driver %s up and running\n", driver_data->name); 1920 cpufreq_debug_enable_ratelimit(); 1921 } 1922 1923 return ret; 1924 } 1925 EXPORT_SYMBOL_GPL(cpufreq_register_driver); 1926 1927 1928 /** 1929 * cpufreq_unregister_driver - unregister the current CPUFreq driver 1930 * 1931 * Unregister the current CPUFreq driver. Only call this if you have 1932 * the right to do so, i.e. if you have succeeded in initialising before! 1933 * Returns zero if successful, and -EINVAL if the cpufreq_driver is 1934 * currently not initialised. 1935 */ 1936 int cpufreq_unregister_driver(struct cpufreq_driver *driver) 1937 { 1938 unsigned long flags; 1939 1940 cpufreq_debug_disable_ratelimit(); 1941 1942 if (!cpufreq_driver || (driver != cpufreq_driver)) { 1943 cpufreq_debug_enable_ratelimit(); 1944 return -EINVAL; 1945 } 1946 1947 dprintk("unregistering driver %s\n", driver->name); 1948 1949 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver); 1950 unregister_hotcpu_notifier(&cpufreq_cpu_notifier); 1951 1952 spin_lock_irqsave(&cpufreq_driver_lock, flags); 1953 cpufreq_driver = NULL; 1954 spin_unlock_irqrestore(&cpufreq_driver_lock, flags); 1955 1956 return 0; 1957 } 1958 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); 1959 1960 static int __init cpufreq_core_init(void) 1961 { 1962 int cpu; 1963 1964 for_each_possible_cpu(cpu) { 1965 per_cpu(policy_cpu, cpu) = -1; 1966 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); 1967 } 1968 return 0; 1969 } 1970 1971 core_initcall(cpufreq_core_init); 1972