drivers/cpufreq/cpufreq.c

   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 struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
  42 #ifdef CONFIG_HOTPLUG_CPU
  43 /* This one keeps track of the previously set governor of a removed CPU */
  44 static struct cpufreq_governor *cpufreq_cpu_governor[NR_CPUS];
  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, unsigned int event);
 108 static unsigned int __cpufreq_get(unsigned int cpu);
 109 static void handle_update(struct work_struct *work);
 110
 111 /**
 112  * Two notifier lists: the "policy" list is involved in the
 113  * validation process for a new CPU frequency policy; the
 114  * "transition" list for kernel code that needs to handle
 115  * changes to devices when the CPU clock speed changes.
 116  * The mutex locks both lists.
 117  */
 118 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
 119 static struct srcu_notifier_head cpufreq_transition_notifier_list;
 120
 121 static int __init init_cpufreq_transition_notifier_list(void)
 122 {
 123         srcu_init_notifier_head(&cpufreq_transition_notifier_list);
 124         return 0;
 125 }
 126 pure_initcall(init_cpufreq_transition_notifier_list);
 127
 128 static LIST_HEAD(cpufreq_governor_list);
 129 static DEFINE_MUTEX (cpufreq_governor_mutex);
 130
 131 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 132 {
 133         struct cpufreq_policy *data;
 134         unsigned long flags;
 135
 136         if (cpu >= NR_CPUS)
 137                 goto err_out;
 138
 139         /* get the cpufreq driver */
 140         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 141
 142         if (!cpufreq_driver)
 143                 goto err_out_unlock;
 144
 145         if (!try_module_get(cpufreq_driver->owner))
 146                 goto err_out_unlock;
 147
 148
 149         /* get the CPU */
 150         data = cpufreq_cpu_data[cpu];
 151
 152         if (!data)
 153                 goto err_out_put_module;
 154
 155         if (!kobject_get(&data->kobj))
 156                 goto err_out_put_module;
 157
 158         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 159         return data;
 160
 161 err_out_put_module:
 162         module_put(cpufreq_driver->owner);
 163 err_out_unlock:
 164         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 165 err_out:
 166         return NULL;
 167 }
 168 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
 169
 170
 171 void cpufreq_cpu_put(struct cpufreq_policy *data)
 172 {
 173         kobject_put(&data->kobj);
 174         module_put(cpufreq_driver->owner);
 175 }
 176 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 177
 178
 179 /*********************************************************************
 180  *                     UNIFIED DEBUG HELPERS                         *
 181  *********************************************************************/
 182 #ifdef CONFIG_CPU_FREQ_DEBUG
 183
 184 /* what part(s) of the CPUfreq subsystem are debugged? */
 185 static unsigned int debug;
 186
 187 /* is the debug output ratelimit'ed using printk_ratelimit? User can
 188  * set or modify this value.
 189  */
 190 static unsigned int debug_ratelimit = 1;
 191
 192 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
 193  * loading of a cpufreq driver, temporarily disabled when a new policy
 194  * is set, and disabled upon cpufreq driver removal
 195  */
 196 static unsigned int disable_ratelimit = 1;
 197 static DEFINE_SPINLOCK(disable_ratelimit_lock);
 198
 199 static void cpufreq_debug_enable_ratelimit(void)
 200 {
 201         unsigned long flags;
 202
 203         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 204         if (disable_ratelimit)
 205                 disable_ratelimit--;
 206         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 207 }
 208
 209 static void cpufreq_debug_disable_ratelimit(void)
 210 {
 211         unsigned long flags;
 212
 213         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 214         disable_ratelimit++;
 215         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 216 }
 217
 218 void cpufreq_debug_printk(unsigned int type, const char *prefix,
 219                                                         const char *fmt, ...)
 220 {
 221         char s[256];
 222         va_list args;
 223         unsigned int len;
 224         unsigned long flags;
 225
 226         WARN_ON(!prefix);
 227         if (type & debug) {
 228                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
 229                 if (!disable_ratelimit && debug_ratelimit
 230                                         && !printk_ratelimit()) {
 231                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 232                         return;
 233                 }
 234                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 235
 236                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
 237
 238                 va_start(args, fmt);
 239                 len += vsnprintf(&s[len], (256 - len), fmt, args);
 240                 va_end(args);
 241
 242                 printk(s);
 243
 244                 WARN_ON(len < 5);
 245         }
 246 }
 247 EXPORT_SYMBOL(cpufreq_debug_printk);
 248
 249
 250 module_param(debug, uint, 0644);
 251 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
 252                         " 2 to debug drivers, and 4 to debug governors.");
 253
 254 module_param(debug_ratelimit, uint, 0644);
 255 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
 256                                         " set to 0 to disable ratelimiting.");
 257
 258 #else /* !CONFIG_CPU_FREQ_DEBUG */
 259
 260 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
 261 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
 262
 263 #endif /* CONFIG_CPU_FREQ_DEBUG */
 264
 265
 266 /*********************************************************************
 267  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 268  *********************************************************************/
 269
 270 /**
 271  * adjust_jiffies - adjust the system "loops_per_jiffy"
 272  *
 273  * This function alters the system "loops_per_jiffy" for the clock
 274  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 275  * systems as each CPU might be scaled differently. So, use the arch
 276  * per-CPU loops_per_jiffy value wherever possible.
 277  */
 278 #ifndef CONFIG_SMP
 279 static unsigned long l_p_j_ref;
 280 static unsigned int  l_p_j_ref_freq;
 281
 282 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 283 {
 284         if (ci->flags & CPUFREQ_CONST_LOOPS)
 285                 return;
 286
 287         if (!l_p_j_ref_freq) {
 288                 l_p_j_ref = loops_per_jiffy;
 289                 l_p_j_ref_freq = ci->old;
 290                 dprintk("saving %lu as reference value for loops_per_jiffy;"
 291                         "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 292         }
 293         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
 294             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
 295             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 296                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
 297                                                                 ci->new);
 298                 dprintk("scaling loops_per_jiffy to %lu"
 299                         "for frequency %u kHz\n", loops_per_jiffy, ci->new);
 300         }
 301 }
 302 #else
 303 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 304 {
 305         return;
 306 }
 307 #endif
 308
 309
 310 /**
 311  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
 312  * on frequency transition.
 313  *
 314  * This function calls the transition notifiers and the "adjust_jiffies"
 315  * function. It is called twice on all CPU frequency changes that have
 316  * external effects.
 317  */
 318 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 319 {
 320         struct cpufreq_policy *policy;
 321
 322         BUG_ON(irqs_disabled());
 323
 324         freqs->flags = cpufreq_driver->flags;
 325         dprintk("notification %u of frequency transition to %u kHz\n",
 326                 state, freqs->new);
 327
 328         policy = cpufreq_cpu_data[freqs->cpu];
 329         switch (state) {
 330
 331         case CPUFREQ_PRECHANGE:
 332                 /* detect if the driver reported a value as "old frequency"
 333                  * which is not equal to what the cpufreq core thinks is
 334                  * "old frequency".
 335                  */
 336                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 337                         if ((policy) && (policy->cpu == freqs->cpu) &&
 338                             (policy->cur) && (policy->cur != freqs->old)) {
 339                                 dprintk("Warning: CPU frequency is"
 340                                         " %u, cpufreq assumed %u kHz.\n",
 341                                         freqs->old, policy->cur);
 342                                 freqs->old = policy->cur;
 343                         }
 344                 }
 345                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 346                                 CPUFREQ_PRECHANGE, freqs);
 347                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 348                 break;
 349
 350         case CPUFREQ_POSTCHANGE:
 351                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 352                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
 353                                 CPUFREQ_POSTCHANGE, freqs);
 354                 if (likely(policy) && likely(policy->cpu == freqs->cpu))
 355                         policy->cur = freqs->new;
 356                 break;
 357         }
 358 }
 359 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
 360
 361
 362
 363 /*********************************************************************
 364  *                          SYSFS INTERFACE                          *
 365  *********************************************************************/
 366
 367 static struct cpufreq_governor *__find_governor(const char *str_governor)
 368 {
 369         struct cpufreq_governor *t;
 370
 371         list_for_each_entry(t, &cpufreq_governor_list, governor_list)
 372                 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN))
 373                         return t;
 374
 375         return NULL;
 376 }
 377
 378 /**
 379  * cpufreq_parse_governor - parse a governor string
 380  */
 381 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
 382                                 struct cpufreq_governor **governor)
 383 {
 384         int err = -EINVAL;
 385
 386         if (!cpufreq_driver)
 387                 goto out;
 388
 389         if (cpufreq_driver->setpolicy) {
 390                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
 391                         *policy = CPUFREQ_POLICY_PERFORMANCE;
 392                         err = 0;
 393                 } else if (!strnicmp(str_governor, "powersave",
 394                                                 CPUFREQ_NAME_LEN)) {
 395                         *policy = CPUFREQ_POLICY_POWERSAVE;
 396                         err = 0;
 397                 }
 398         } else if (cpufreq_driver->target) {
 399                 struct cpufreq_governor *t;
 400
 401                 mutex_lock(&cpufreq_governor_mutex);
 402
 403                 t = __find_governor(str_governor);
 404
 405                 if (t == NULL) {
 406                         char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
 407                                                                 str_governor);
 408
 409                         if (name) {
 410                                 int ret;
 411
 412                                 mutex_unlock(&cpufreq_governor_mutex);
 413                                 ret = request_module(name);
 414                                 mutex_lock(&cpufreq_governor_mutex);
 415
 416                                 if (ret == 0)
 417                                         t = __find_governor(str_governor);
 418                         }
 419
 420                         kfree(name);
 421                 }
 422
 423                 if (t != NULL) {
 424                         *governor = t;
 425                         err = 0;
 426                 }
 427
 428                 mutex_unlock(&cpufreq_governor_mutex);
 429         }
 430   out:
 431         return err;
 432 }
 433
 434
 435 /* drivers/base/cpu.c */
 436 extern struct sysdev_class cpu_sysdev_class;
 437
 438
 439 /**
 440  * cpufreq_per_cpu_attr_read() / show_##file_name() -
 441  * print out cpufreq information
 442  *
 443  * Write out information from cpufreq_driver->policy[cpu]; object must be
 444  * "unsigned int".
 445  */
 446
 447 #define show_one(file_name, object)                     \
 448 static ssize_t show_##file_name                         \
 449 (struct cpufreq_policy * policy, char *buf)             \
 450 {                                                       \
 451         return sprintf (buf, "%u\n", policy->object);   \
 452 }
 453
 454 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 455 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 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,
 507                                                         char *buf)
 508 {
 509         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
 510                 return sprintf(buf, "powersave\n");
 511         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 512                 return sprintf(buf, "performance\n");
 513         else if (policy->governor)
 514                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", 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)) - (CPUFREQ_NAME_LEN + 2)))
 578                         goto out;
 579                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
 580         }
 581 out:
 582         i += sprintf(&buf[i], "\n");
 583         return i;
 584 }
 585 /**
 586  * show_affected_cpus - show the CPUs affected by each transition
 587  */
 588 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
 589 {
 590         ssize_t i = 0;
 591         unsigned int cpu;
 592
 593         for_each_cpu_mask(cpu, policy->cpus) {
 594                 if (i)
 595                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 596                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 597                 if (i >= (PAGE_SIZE - 5))
 598                     break;
 599         }
 600         i += sprintf(&buf[i], "\n");
 601         return i;
 602 }
 603
 604
 605 #define define_one_ro(_name) \
 606 static struct freq_attr _name = \
 607 __ATTR(_name, 0444, show_##_name, NULL)
 608
 609 #define define_one_ro0400(_name) \
 610 static struct freq_attr _name = \
 611 __ATTR(_name, 0400, show_##_name, NULL)
 612
 613 #define define_one_rw(_name) \
 614 static struct freq_attr _name = \
 615 __ATTR(_name, 0644, show_##_name, store_##_name)
 616
 617 define_one_ro0400(cpuinfo_cur_freq);
 618 define_one_ro(cpuinfo_min_freq);
 619 define_one_ro(cpuinfo_max_freq);
 620 define_one_ro(scaling_available_governors);
 621 define_one_ro(scaling_driver);
 622 define_one_ro(scaling_cur_freq);
 623 define_one_ro(affected_cpus);
 624 define_one_rw(scaling_min_freq);
 625 define_one_rw(scaling_max_freq);
 626 define_one_rw(scaling_governor);
 627
 628 static struct attribute * default_attrs[] = {
 629         &cpuinfo_min_freq.attr,
 630         &cpuinfo_max_freq.attr,
 631         &scaling_min_freq.attr,
 632         &scaling_max_freq.attr,
 633         &affected_cpus.attr,
 634         &scaling_governor.attr,
 635         &scaling_driver.attr,
 636         &scaling_available_governors.attr,
 637         NULL
 638 };
 639
 640 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
 641 #define to_attr(a) container_of(a,struct freq_attr,attr)
 642
 643 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
 644 {
 645         struct cpufreq_policy * policy = to_policy(kobj);
 646         struct freq_attr * fattr = to_attr(attr);
 647         ssize_t ret;
 648         policy = cpufreq_cpu_get(policy->cpu);
 649         if (!policy)
 650                 return -EINVAL;
 651
 652         if (lock_policy_rwsem_read(policy->cpu) < 0)
 653                 return -EINVAL;
 654
 655         if (fattr->show)
 656                 ret = fattr->show(policy, buf);
 657         else
 658                 ret = -EIO;
 659
 660         unlock_policy_rwsem_read(policy->cpu);
 661
 662         cpufreq_cpu_put(policy);
 663         return ret;
 664 }
 665
 666 static ssize_t store(struct kobject * kobj, struct attribute * attr,
 667                      const char * buf, size_t count)
 668 {
 669         struct cpufreq_policy * policy = to_policy(kobj);
 670         struct freq_attr * fattr = to_attr(attr);
 671         ssize_t ret;
 672         policy = cpufreq_cpu_get(policy->cpu);
 673         if (!policy)
 674                 return -EINVAL;
 675
 676         if (lock_policy_rwsem_write(policy->cpu) < 0)
 677                 return -EINVAL;
 678
 679         if (fattr->store)
 680                 ret = fattr->store(policy, buf, count);
 681         else
 682                 ret = -EIO;
 683
 684         unlock_policy_rwsem_write(policy->cpu);
 685
 686         cpufreq_cpu_put(policy);
 687         return ret;
 688 }
 689
 690 static void cpufreq_sysfs_release(struct kobject * kobj)
 691 {
 692         struct cpufreq_policy * policy = to_policy(kobj);
 693         dprintk("last reference is dropped\n");
 694         complete(&policy->kobj_unregister);
 695 }
 696
 697 static struct sysfs_ops sysfs_ops = {
 698         .show   = show,
 699         .store  = store,
 700 };
 701
 702 static struct kobj_type ktype_cpufreq = {
 703         .sysfs_ops      = &sysfs_ops,
 704         .default_attrs  = default_attrs,
 705         .release        = cpufreq_sysfs_release,
 706 };
 707
 708
 709 /**
 710  * cpufreq_add_dev - add a CPU device
 711  *
 712  * Adds the cpufreq interface for a CPU device.
 713  */
 714 static int cpufreq_add_dev (struct sys_device * sys_dev)
 715 {
 716         unsigned int cpu = sys_dev->id;
 717         int ret = 0;
 718         struct cpufreq_policy new_policy;
 719         struct cpufreq_policy *policy;
 720         struct freq_attr **drv_attr;
 721         struct sys_device *cpu_sys_dev;
 722         unsigned long flags;
 723         unsigned int j;
 724 #ifdef CONFIG_SMP
 725         struct cpufreq_policy *managed_policy;
 726 #endif
 727
 728         if (cpu_is_offline(cpu))
 729                 return 0;
 730
 731         cpufreq_debug_disable_ratelimit();
 732         dprintk("adding CPU %u\n", cpu);
 733
 734 #ifdef CONFIG_SMP
 735         /* check whether a different CPU already registered this
 736          * CPU because it is in the same boat. */
 737         policy = cpufreq_cpu_get(cpu);
 738         if (unlikely(policy)) {
 739                 cpufreq_cpu_put(policy);
 740                 cpufreq_debug_enable_ratelimit();
 741                 return 0;
 742         }
 743 #endif
 744
 745         if (!try_module_get(cpufreq_driver->owner)) {
 746                 ret = -EINVAL;
 747                 goto module_out;
 748         }
 749
 750         policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
 751         if (!policy) {
 752                 ret = -ENOMEM;
 753                 goto nomem_out;
 754         }
 755
 756         policy->cpu = cpu;
 757         policy->cpus = cpumask_of_cpu(cpu);
 758
 759         /* Initially set CPU itself as the policy_cpu */
 760         per_cpu(policy_cpu, cpu) = cpu;
 761         lock_policy_rwsem_write(cpu);
 762
 763         init_completion(&policy->kobj_unregister);
 764         INIT_WORK(&policy->update, handle_update);
 765
 766         /* Set governor before ->init, so that driver could check it */
 767         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 768         /* call driver. From then on the cpufreq must be able
 769          * to accept all calls to ->verify and ->setpolicy for this CPU
 770          */
 771         ret = cpufreq_driver->init(policy);
 772         if (ret) {
 773                 dprintk("initialization failed\n");
 774                 unlock_policy_rwsem_write(cpu);
 775                 goto err_out;
 776         }
 777         policy->user_policy.min = policy->cpuinfo.min_freq;
 778         policy->user_policy.max = policy->cpuinfo.max_freq;
 779
 780 #ifdef CONFIG_SMP
 781
 782 #ifdef CONFIG_HOTPLUG_CPU
 783         if (cpufreq_cpu_governor[cpu]){
 784                 policy->governor = cpufreq_cpu_governor[cpu];
 785                 dprintk("Restoring governor %s for cpu %d\n",
 786                        policy->governor->name, cpu);
 787         }
 788 #endif
 789
 790         for_each_cpu_mask(j, policy->cpus) {
 791                 if (cpu == j)
 792                         continue;
 793
 794                 /* check for existing affected CPUs.  They may not be aware
 795                  * of it due to CPU Hotplug.
 796                  */
 797                 managed_policy = cpufreq_cpu_get(j);
 798                 if (unlikely(managed_policy)) {
 799
 800                         /* Set proper policy_cpu */
 801                         unlock_policy_rwsem_write(cpu);
 802                         per_cpu(policy_cpu, cpu) = managed_policy->cpu;
 803
 804                         if (lock_policy_rwsem_write(cpu) < 0)
 805                                 goto err_out_driver_exit;
 806
 807                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 808                         managed_policy->cpus = policy->cpus;
 809                         cpufreq_cpu_data[cpu] = managed_policy;
 810                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 811
 812                         dprintk("CPU already managed, adding link\n");
 813                         ret = sysfs_create_link(&sys_dev->kobj,
 814                                                 &managed_policy->kobj,
 815                                                 "cpufreq");
 816                         if (ret) {
 817                                 unlock_policy_rwsem_write(cpu);
 818                                 goto err_out_driver_exit;
 819                         }
 820
 821                         cpufreq_debug_enable_ratelimit();
 822                         ret = 0;
 823                         unlock_policy_rwsem_write(cpu);
 824                         goto err_out_driver_exit; /* call driver->exit() */
 825                 }
 826         }
 827 #endif
 828         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
 829
 830         /* prepare interface data */
 831         policy->kobj.parent = &sys_dev->kobj;
 832         policy->kobj.ktype = &ktype_cpufreq;
 833         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
 834
 835         ret = kobject_register(&policy->kobj);
 836         if (ret) {
 837                 unlock_policy_rwsem_write(cpu);
 838                 goto err_out_driver_exit;
 839         }
 840         /* set up files for this cpu device */
 841         drv_attr = cpufreq_driver->attr;
 842         while ((drv_attr) && (*drv_attr)) {
 843                 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 844                 if (ret)
 845                         goto err_out_driver_exit;
 846                 drv_attr++;
 847         }
 848         if (cpufreq_driver->get){
 849                 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
 850                 if (ret)
 851                         goto err_out_driver_exit;
 852         }
 853         if (cpufreq_driver->target){
 854                 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 855                 if (ret)
 856                         goto err_out_driver_exit;
 857         }
 858
 859         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 860         for_each_cpu_mask(j, policy->cpus) {
 861                 cpufreq_cpu_data[j] = policy;
 862                 per_cpu(policy_cpu, j) = policy->cpu;
 863         }
 864         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 865
 866         /* symlink affected CPUs */
 867         for_each_cpu_mask(j, policy->cpus) {
 868                 if (j == cpu)
 869                         continue;
 870                 if (!cpu_online(j))
 871                         continue;
 872
 873                 dprintk("CPU %u already managed, adding link\n", j);
 874                 cpufreq_cpu_get(cpu);
 875                 cpu_sys_dev = get_cpu_sysdev(j);
 876                 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
 877                                         "cpufreq");
 878                 if (ret) {
 879                         unlock_policy_rwsem_write(cpu);
 880                         goto err_out_unregister;
 881                 }
 882         }
 883
 884         policy->governor = NULL; /* to assure that the starting sequence is
 885                                   * run in cpufreq_set_policy */
 886
 887         /* set default policy */
 888         ret = __cpufreq_set_policy(policy, &new_policy);
 889         policy->user_policy.policy = policy->policy;
 890         policy->user_policy.governor = policy->governor;
 891
 892         unlock_policy_rwsem_write(cpu);
 893
 894         if (ret) {
 895                 dprintk("setting policy failed\n");
 896                 goto err_out_unregister;
 897         }
 898
 899         module_put(cpufreq_driver->owner);
 900         dprintk("initialization complete\n");
 901         cpufreq_debug_enable_ratelimit();
 902
 903         return 0;
 904
 905
 906 err_out_unregister:
 907         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 908         for_each_cpu_mask(j, policy->cpus)
 909                 cpufreq_cpu_data[j] = NULL;
 910         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 911
 912         kobject_unregister(&policy->kobj);
 913         wait_for_completion(&policy->kobj_unregister);
 914
 915 err_out_driver_exit:
 916         if (cpufreq_driver->exit)
 917                 cpufreq_driver->exit(policy);
 918
 919 err_out:
 920         kfree(policy);
 921
 922 nomem_out:
 923         module_put(cpufreq_driver->owner);
 924 module_out:
 925         cpufreq_debug_enable_ratelimit();
 926         return ret;
 927 }
 928
 929
 930 /**
 931  * __cpufreq_remove_dev - remove a CPU device
 932  *
 933  * Removes the cpufreq interface for a CPU device.
 934  * Caller should already have policy_rwsem in write mode for this CPU.
 935  * This routine frees the rwsem before returning.
 936  */
 937 static int __cpufreq_remove_dev (struct sys_device * sys_dev)
 938 {
 939         unsigned int cpu = sys_dev->id;
 940         unsigned long flags;
 941         struct cpufreq_policy *data;
 942 #ifdef CONFIG_SMP
 943         struct sys_device *cpu_sys_dev;
 944         unsigned int j;
 945 #endif
 946
 947         cpufreq_debug_disable_ratelimit();
 948         dprintk("unregistering CPU %u\n", cpu);
 949
 950         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 951         data = cpufreq_cpu_data[cpu];
 952
 953         if (!data) {
 954                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 955                 cpufreq_debug_enable_ratelimit();
 956                 unlock_policy_rwsem_write(cpu);
 957                 return -EINVAL;
 958         }
 959         cpufreq_cpu_data[cpu] = NULL;
 960
 961
 962 #ifdef CONFIG_SMP
 963         /* if this isn't the CPU which is the parent of the kobj, we
 964          * only need to unlink, put and exit
 965          */
 966         if (unlikely(cpu != data->cpu)) {
 967                 dprintk("removing link\n");
 968                 cpu_clear(cpu, data->cpus);
 969                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 970                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
 971                 cpufreq_cpu_put(data);
 972                 cpufreq_debug_enable_ratelimit();
 973                 unlock_policy_rwsem_write(cpu);
 974                 return 0;
 975         }
 976 #endif
 977
 978
 979         if (!kobject_get(&data->kobj)) {
 980                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 981                 cpufreq_debug_enable_ratelimit();
 982                 unlock_policy_rwsem_write(cpu);
 983                 return -EFAULT;
 984         }
 985
 986 #ifdef CONFIG_SMP
 987
 988 #ifdef CONFIG_HOTPLUG_CPU
 989         cpufreq_cpu_governor[cpu] = data->governor;
 990 #endif
 991
 992         /* if we have other CPUs still registered, we need to unlink them,
 993          * or else wait_for_completion below will lock up. Clean the
 994          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
 995          * links afterwards.
 996          */
 997         if (unlikely(cpus_weight(data->cpus) > 1)) {
 998                 for_each_cpu_mask(j, data->cpus) {
 999                         if (j == cpu)
1000                                 continue;
1001                         cpufreq_cpu_data[j] = NULL;
1002                 }
1003         }
1004
1005         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1006
1007         if (unlikely(cpus_weight(data->cpus) > 1)) {
1008                 for_each_cpu_mask(j, data->cpus) {
1009                         if (j == cpu)
1010                                 continue;
1011                         dprintk("removing link for cpu %u\n", j);
1012 #ifdef CONFIG_HOTPLUG_CPU
1013                         cpufreq_cpu_governor[j] = data->governor;
1014 #endif
1015                         cpu_sys_dev = get_cpu_sysdev(j);
1016                         sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1017                         cpufreq_cpu_put(data);
1018                 }
1019         }
1020 #else
1021         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1022 #endif
1023
1024         if (cpufreq_driver->target)
1025                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1026
1027         unlock_policy_rwsem_write(cpu);
1028
1029         kobject_unregister(&data->kobj);
1030
1031         kobject_put(&data->kobj);
1032
1033         /* we need to make sure that the underlying kobj is actually
1034          * not referenced anymore by anybody before we proceed with
1035          * unloading.
1036          */
1037         dprintk("waiting for dropping of refcount\n");
1038         wait_for_completion(&data->kobj_unregister);
1039         dprintk("wait complete\n");
1040
1041         if (cpufreq_driver->exit)
1042                 cpufreq_driver->exit(data);
1043
1044         kfree(data);
1045
1046         cpufreq_debug_enable_ratelimit();
1047         return 0;
1048 }
1049
1050
1051 static int cpufreq_remove_dev (struct sys_device * sys_dev)
1052 {
1053         unsigned int cpu = sys_dev->id;
1054         int retval;
1055
1056         if (cpu_is_offline(cpu))
1057                 return 0;
1058
1059         if (unlikely(lock_policy_rwsem_write(cpu)))
1060                 BUG();
1061
1062         retval = __cpufreq_remove_dev(sys_dev);
1063         return retval;
1064 }
1065
1066
1067 static void handle_update(struct work_struct *work)
1068 {
1069         struct cpufreq_policy *policy =
1070                 container_of(work, struct cpufreq_policy, update);
1071         unsigned int cpu = policy->cpu;
1072         dprintk("handle_update for cpu %u called\n", cpu);
1073         cpufreq_update_policy(cpu);
1074 }
1075
1076 /**
1077  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1078  *      @cpu: cpu number
1079  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
1080  *      @new_freq: CPU frequency the CPU actually runs at
1081  *
1082  *      We adjust to current frequency first, and need to clean up later. So either call
1083  *      to cpufreq_update_policy() or schedule handle_update()).
1084  */
1085 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1086                                 unsigned int new_freq)
1087 {
1088         struct cpufreq_freqs freqs;
1089
1090         dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1091                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1092
1093         freqs.cpu = cpu;
1094         freqs.old = old_freq;
1095         freqs.new = new_freq;
1096         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1097         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1098 }
1099
1100
1101 /**
1102  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1103  * @cpu: CPU number
1104  *
1105  * This is the last known freq, without actually getting it from the driver.
1106  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1107  */
1108 unsigned int cpufreq_quick_get(unsigned int cpu)
1109 {
1110         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1111         unsigned int ret_freq = 0;
1112
1113         if (policy) {
1114                 ret_freq = policy->cur;
1115                 cpufreq_cpu_put(policy);
1116         }
1117
1118         return (ret_freq);
1119 }
1120 EXPORT_SYMBOL(cpufreq_quick_get);
1121
1122
1123 static unsigned int __cpufreq_get(unsigned int cpu)
1124 {
1125         struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1126         unsigned int ret_freq = 0;
1127
1128         if (!cpufreq_driver->get)
1129                 return (ret_freq);
1130
1131         ret_freq = cpufreq_driver->get(cpu);
1132
1133         if (ret_freq && policy->cur &&
1134                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1135                 /* verify no discrepancy between actual and
1136                                         saved value exists */
1137                 if (unlikely(ret_freq != policy->cur)) {
1138                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1139                         schedule_work(&policy->update);
1140                 }
1141         }
1142
1143         return (ret_freq);
1144 }
1145
1146 /**
1147  * cpufreq_get - get the current CPU frequency (in kHz)
1148  * @cpu: CPU number
1149  *
1150  * Get the CPU current (static) CPU frequency
1151  */
1152 unsigned int cpufreq_get(unsigned int cpu)
1153 {
1154         unsigned int ret_freq = 0;
1155         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1156
1157         if (!policy)
1158                 goto out;
1159
1160         if (unlikely(lock_policy_rwsem_read(cpu)))
1161                 goto out_policy;
1162
1163         ret_freq = __cpufreq_get(cpu);
1164
1165         unlock_policy_rwsem_read(cpu);
1166
1167 out_policy:
1168         cpufreq_cpu_put(policy);
1169 out:
1170         return (ret_freq);
1171 }
1172 EXPORT_SYMBOL(cpufreq_get);
1173
1174
1175 /**
1176  *      cpufreq_suspend - let the low level driver prepare for suspend
1177  */
1178
1179 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
1180 {
1181         int cpu = sysdev->id;
1182         int ret = 0;
1183         unsigned int cur_freq = 0;
1184         struct cpufreq_policy *cpu_policy;
1185
1186         dprintk("suspending cpu %u\n", cpu);
1187
1188         if (!cpu_online(cpu))
1189                 return 0;
1190
1191         /* we may be lax here as interrupts are off. Nonetheless
1192          * we need to grab the correct cpu policy, as to check
1193          * whether we really run on this CPU.
1194          */
1195
1196         cpu_policy = cpufreq_cpu_get(cpu);
1197         if (!cpu_policy)
1198                 return -EINVAL;
1199
1200         /* only handle each CPU group once */
1201         if (unlikely(cpu_policy->cpu != cpu)) {
1202                 cpufreq_cpu_put(cpu_policy);
1203                 return 0;
1204         }
1205
1206         if (cpufreq_driver->suspend) {
1207                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1208                 if (ret) {
1209                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1210                                         "step on CPU %u\n", cpu_policy->cpu);
1211                         cpufreq_cpu_put(cpu_policy);
1212                         return ret;
1213                 }
1214         }
1215
1216
1217         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1218                 goto out;
1219
1220         if (cpufreq_driver->get)
1221                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1222
1223         if (!cur_freq || !cpu_policy->cur) {
1224                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1225                        "frequency is what timing core thinks it is.\n");
1226                 goto out;
1227         }
1228
1229         if (unlikely(cur_freq != cpu_policy->cur)) {
1230                 struct cpufreq_freqs freqs;
1231
1232                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1233                         dprintk("Warning: CPU frequency is %u, "
1234                                "cpufreq assumed %u kHz.\n",
1235                                cur_freq, cpu_policy->cur);
1236
1237                 freqs.cpu = cpu;
1238                 freqs.old = cpu_policy->cur;
1239                 freqs.new = cur_freq;
1240
1241                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1242                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1243                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1244
1245                 cpu_policy->cur = cur_freq;
1246         }
1247
1248 out:
1249         cpufreq_cpu_put(cpu_policy);
1250         return 0;
1251 }
1252
1253 /**
1254  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1255  *
1256  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1257  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1258  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1259  *          restored.
1260  */
1261 static int cpufreq_resume(struct sys_device * sysdev)
1262 {
1263         int cpu = sysdev->id;
1264         int ret = 0;
1265         struct cpufreq_policy *cpu_policy;
1266
1267         dprintk("resuming cpu %u\n", cpu);
1268
1269         if (!cpu_online(cpu))
1270                 return 0;
1271
1272         /* we may be lax here as interrupts are off. Nonetheless
1273          * we need to grab the correct cpu policy, as to check
1274          * whether we really run on this CPU.
1275          */
1276
1277         cpu_policy = cpufreq_cpu_get(cpu);
1278         if (!cpu_policy)
1279                 return -EINVAL;
1280
1281         /* only handle each CPU group once */
1282         if (unlikely(cpu_policy->cpu != cpu)) {
1283                 cpufreq_cpu_put(cpu_policy);
1284                 return 0;
1285         }
1286
1287         if (cpufreq_driver->resume) {
1288                 ret = cpufreq_driver->resume(cpu_policy);
1289                 if (ret) {
1290                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1291                                         "step on CPU %u\n", cpu_policy->cpu);
1292                         cpufreq_cpu_put(cpu_policy);
1293                         return ret;
1294                 }
1295         }
1296
1297         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1298                 unsigned int cur_freq = 0;
1299
1300                 if (cpufreq_driver->get)
1301                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1302
1303                 if (!cur_freq || !cpu_policy->cur) {
1304                         printk(KERN_ERR "cpufreq: resume failed to assert "
1305                                         "current frequency is what timing core "
1306                                         "thinks it is.\n");
1307                         goto out;
1308                 }
1309
1310                 if (unlikely(cur_freq != cpu_policy->cur)) {
1311                         struct cpufreq_freqs freqs;
1312
1313                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1314                                 dprintk("Warning: CPU frequency"
1315                                        "is %u, cpufreq assumed %u kHz.\n",
1316                                        cur_freq, cpu_policy->cur);
1317
1318                         freqs.cpu = cpu;
1319                         freqs.old = cpu_policy->cur;
1320                         freqs.new = cur_freq;
1321
1322                         srcu_notifier_call_chain(
1323                                         &cpufreq_transition_notifier_list,
1324                                         CPUFREQ_RESUMECHANGE, &freqs);
1325                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1326
1327                         cpu_policy->cur = cur_freq;
1328                 }
1329         }
1330
1331 out:
1332         schedule_work(&cpu_policy->update);
1333         cpufreq_cpu_put(cpu_policy);
1334         return ret;
1335 }
1336
1337 static struct sysdev_driver cpufreq_sysdev_driver = {
1338         .add            = cpufreq_add_dev,
1339         .remove         = cpufreq_remove_dev,
1340         .suspend        = cpufreq_suspend,
1341         .resume         = cpufreq_resume,
1342 };
1343
1344
1345 /*********************************************************************
1346  *                     NOTIFIER LISTS INTERFACE                      *
1347  *********************************************************************/
1348
1349 /**
1350  *      cpufreq_register_notifier - register a driver with cpufreq
1351  *      @nb: notifier function to register
1352  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1353  *
1354  *      Add a driver to one of two lists: either a list of drivers that
1355  *      are notified about clock rate changes (once before and once after
1356  *      the transition), or a list of drivers that are notified about
1357  *      changes in cpufreq policy.
1358  *
1359  *      This function may sleep, and has the same return conditions as
1360  *      blocking_notifier_chain_register.
1361  */
1362 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1363 {
1364         int ret;
1365
1366         switch (list) {
1367         case CPUFREQ_TRANSITION_NOTIFIER:
1368                 ret = srcu_notifier_chain_register(
1369                                 &cpufreq_transition_notifier_list, nb);
1370                 break;
1371         case CPUFREQ_POLICY_NOTIFIER:
1372                 ret = blocking_notifier_chain_register(
1373                                 &cpufreq_policy_notifier_list, nb);
1374                 break;
1375         default:
1376                 ret = -EINVAL;
1377         }
1378
1379         return ret;
1380 }
1381 EXPORT_SYMBOL(cpufreq_register_notifier);
1382
1383
1384 /**
1385  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1386  *      @nb: notifier block to be unregistered
1387  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1388  *
1389  *      Remove a driver from the CPU frequency notifier list.
1390  *
1391  *      This function may sleep, and has the same return conditions as
1392  *      blocking_notifier_chain_unregister.
1393  */
1394 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1395 {
1396         int ret;
1397
1398         switch (list) {
1399         case CPUFREQ_TRANSITION_NOTIFIER:
1400                 ret = srcu_notifier_chain_unregister(
1401                                 &cpufreq_transition_notifier_list, nb);
1402                 break;
1403         case CPUFREQ_POLICY_NOTIFIER:
1404                 ret = blocking_notifier_chain_unregister(
1405                                 &cpufreq_policy_notifier_list, nb);
1406                 break;
1407         default:
1408                 ret = -EINVAL;
1409         }
1410
1411         return ret;
1412 }
1413 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1414
1415
1416 /*********************************************************************
1417  *                              GOVERNORS                            *
1418  *********************************************************************/
1419
1420
1421 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1422                             unsigned int target_freq,
1423                             unsigned int relation)
1424 {
1425         int retval = -EINVAL;
1426
1427         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1428                 target_freq, relation);
1429         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1430                 retval = cpufreq_driver->target(policy, target_freq, relation);
1431
1432         return retval;
1433 }
1434 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1435
1436 int cpufreq_driver_target(struct cpufreq_policy *policy,
1437                           unsigned int target_freq,
1438                           unsigned int relation)
1439 {
1440         int ret;
1441
1442         policy = cpufreq_cpu_get(policy->cpu);
1443         if (!policy)
1444                 return -EINVAL;
1445
1446         if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1447                 return -EINVAL;
1448
1449         ret = __cpufreq_driver_target(policy, target_freq, relation);
1450
1451         unlock_policy_rwsem_write(policy->cpu);
1452
1453         cpufreq_cpu_put(policy);
1454         return ret;
1455 }
1456 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1457
1458 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1459 {
1460         int ret = 0;
1461
1462         policy = cpufreq_cpu_get(policy->cpu);
1463         if (!policy)
1464                 return -EINVAL;
1465
1466         if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1467                 ret = cpufreq_driver->getavg(policy->cpu);
1468
1469         cpufreq_cpu_put(policy);
1470         return ret;
1471 }
1472 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1473
1474 /*
1475  * when "event" is CPUFREQ_GOV_LIMITS
1476  */
1477
1478 static int __cpufreq_governor(struct cpufreq_policy *policy,
1479                                         unsigned int event)
1480 {
1481         int ret;
1482
1483         /* Only must be defined when default governor is known to have latency
1484            restrictions, like e.g. conservative or ondemand.
1485            That this is the case is already ensured in Kconfig
1486         */
1487 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1488         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1489 #else
1490         struct cpufreq_governor *gov = NULL;
1491 #endif
1492
1493         if (policy->governor->max_transition_latency &&
1494             policy->cpuinfo.transition_latency >
1495             policy->governor->max_transition_latency) {
1496                 if (!gov)
1497                         return -EINVAL;
1498                 else {
1499                         printk(KERN_WARNING "%s governor failed, too long"
1500                                " transition latency of HW, fallback"
1501                                " to %s governor\n",
1502                                policy->governor->name,
1503                                gov->name);
1504                         policy->governor = gov;
1505                 }
1506         }
1507
1508         if (!try_module_get(policy->governor->owner))
1509                 return -EINVAL;
1510
1511         dprintk("__cpufreq_governor for CPU %u, event %u\n",
1512                                                 policy->cpu, event);
1513         ret = policy->governor->governor(policy, event);
1514
1515         /* we keep one module reference alive for
1516                         each CPU governed by this CPU */
1517         if ((event != CPUFREQ_GOV_START) || ret)
1518                 module_put(policy->governor->owner);
1519         if ((event == CPUFREQ_GOV_STOP) && !ret)
1520                 module_put(policy->governor->owner);
1521
1522         return ret;
1523 }
1524
1525
1526 int cpufreq_register_governor(struct cpufreq_governor *governor)
1527 {
1528         int err;
1529
1530         if (!governor)
1531                 return -EINVAL;
1532
1533         mutex_lock(&cpufreq_governor_mutex);
1534
1535         err = -EBUSY;
1536         if (__find_governor(governor->name) == NULL) {
1537                 err = 0;
1538                 list_add(&governor->governor_list, &cpufreq_governor_list);
1539         }
1540
1541         mutex_unlock(&cpufreq_governor_mutex);
1542         return err;
1543 }
1544 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1545
1546
1547 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1548 {
1549         if (!governor)
1550                 return;
1551
1552         mutex_lock(&cpufreq_governor_mutex);
1553         list_del(&governor->governor_list);
1554         mutex_unlock(&cpufreq_governor_mutex);
1555         return;
1556 }
1557 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1558
1559
1560
1561 /*********************************************************************
1562  *                          POLICY INTERFACE                         *
1563  *********************************************************************/
1564
1565 /**
1566  * cpufreq_get_policy - get the current cpufreq_policy
1567  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1568  *
1569  * Reads the current cpufreq policy.
1570  */
1571 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1572 {
1573         struct cpufreq_policy *cpu_policy;
1574         if (!policy)
1575                 return -EINVAL;
1576
1577         cpu_policy = cpufreq_cpu_get(cpu);
1578         if (!cpu_policy)
1579                 return -EINVAL;
1580
1581         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1582
1583         cpufreq_cpu_put(cpu_policy);
1584         return 0;
1585 }
1586 EXPORT_SYMBOL(cpufreq_get_policy);
1587
1588
1589 /*
1590  * data   : current policy.
1591  * policy : policy to be set.
1592  */
1593 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1594                                 struct cpufreq_policy *policy)
1595 {
1596         int ret = 0;
1597
1598         cpufreq_debug_disable_ratelimit();
1599         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1600                 policy->min, policy->max);
1601
1602         memcpy(&policy->cpuinfo, &data->cpuinfo,
1603                                 sizeof(struct cpufreq_cpuinfo));
1604
1605         if (policy->min > data->min && policy->min > policy->max) {
1606                 ret = -EINVAL;
1607                 goto error_out;
1608         }
1609
1610         /* verify the cpu speed can be set within this limit */
1611         ret = cpufreq_driver->verify(policy);
1612         if (ret)
1613                 goto error_out;
1614
1615         /* adjust if necessary - all reasons */
1616         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1617                         CPUFREQ_ADJUST, policy);
1618
1619         /* adjust if necessary - hardware incompatibility*/
1620         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1621                         CPUFREQ_INCOMPATIBLE, policy);
1622
1623         /* verify the cpu speed can be set within this limit,
1624            which might be different to the first one */
1625         ret = cpufreq_driver->verify(policy);
1626         if (ret)
1627                 goto error_out;
1628
1629         /* notification of the new policy */
1630         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1631                         CPUFREQ_NOTIFY, policy);
1632
1633         data->min = policy->min;
1634         data->max = policy->max;
1635
1636         dprintk("new min and max freqs are %u - %u kHz\n",
1637                                         data->min, data->max);
1638
1639         if (cpufreq_driver->setpolicy) {
1640                 data->policy = policy->policy;
1641                 dprintk("setting range\n");
1642                 ret = cpufreq_driver->setpolicy(policy);
1643         } else {
1644                 if (policy->governor != data->governor) {
1645                         /* save old, working values */
1646                         struct cpufreq_governor *old_gov = data->governor;
1647
1648                         dprintk("governor switch\n");
1649
1650                         /* end old governor */
1651                         if (data->governor)
1652                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1653
1654                         /* start new governor */
1655                         data->governor = policy->governor;
1656                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1657                                 /* new governor failed, so re-start old one */
1658                                 dprintk("starting governor %s failed\n",
1659                                                         data->governor->name);
1660                                 if (old_gov) {
1661                                         data->governor = old_gov;
1662                                         __cpufreq_governor(data,
1663                                                            CPUFREQ_GOV_START);
1664                                 }
1665                                 ret = -EINVAL;
1666                                 goto error_out;
1667                         }
1668                         /* might be a policy change, too, so fall through */
1669                 }
1670                 dprintk("governor: change or update limits\n");
1671                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1672         }
1673
1674 error_out:
1675         cpufreq_debug_enable_ratelimit();
1676         return ret;
1677 }
1678
1679 /**
1680  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1681  *      @cpu: CPU which shall be re-evaluated
1682  *
1683  *      Usefull for policy notifiers which have different necessities
1684  *      at different times.
1685  */
1686 int cpufreq_update_policy(unsigned int cpu)
1687 {
1688         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1689         struct cpufreq_policy policy;
1690         int ret = 0;
1691
1692         if (!data)
1693                 return -ENODEV;
1694
1695         if (unlikely(lock_policy_rwsem_write(cpu)))
1696                 return -EINVAL;
1697
1698         dprintk("updating policy for CPU %u\n", cpu);
1699         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1700         policy.min = data->user_policy.min;
1701         policy.max = data->user_policy.max;
1702         policy.policy = data->user_policy.policy;
1703         policy.governor = data->user_policy.governor;
1704
1705         /* BIOS might change freq behind our back
1706           -> ask driver for current freq and notify governors about a change */
1707         if (cpufreq_driver->get) {
1708                 policy.cur = cpufreq_driver->get(cpu);
1709                 if (!data->cur) {
1710                         dprintk("Driver did not initialize current freq");
1711                         data->cur = policy.cur;
1712                 } else {
1713                         if (data->cur != policy.cur)
1714                                 cpufreq_out_of_sync(cpu, data->cur,
1715                                                                 policy.cur);
1716                 }
1717         }
1718
1719         ret = __cpufreq_set_policy(data, &policy);
1720
1721         unlock_policy_rwsem_write(cpu);
1722
1723         cpufreq_cpu_put(data);
1724         return ret;
1725 }
1726 EXPORT_SYMBOL(cpufreq_update_policy);
1727
1728 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1729                                         unsigned long action, void *hcpu)
1730 {
1731         unsigned int cpu = (unsigned long)hcpu;
1732         struct sys_device *sys_dev;
1733
1734         sys_dev = get_cpu_sysdev(cpu);
1735         if (sys_dev) {
1736                 switch (action) {
1737                 case CPU_ONLINE:
1738                 case CPU_ONLINE_FROZEN:
1739                         cpufreq_add_dev(sys_dev);
1740                         break;
1741                 case CPU_DOWN_PREPARE:
1742                 case CPU_DOWN_PREPARE_FROZEN:
1743                         if (unlikely(lock_policy_rwsem_write(cpu)))
1744                                 BUG();
1745
1746                         __cpufreq_remove_dev(sys_dev);
1747                         break;
1748                 case CPU_DOWN_FAILED:
1749                 case CPU_DOWN_FAILED_FROZEN:
1750                         cpufreq_add_dev(sys_dev);
1751                         break;
1752                 }
1753         }
1754         return NOTIFY_OK;
1755 }
1756
1757 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1758 {
1759     .notifier_call = cpufreq_cpu_callback,
1760 };
1761
1762 /*********************************************************************
1763  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1764  *********************************************************************/
1765
1766 /**
1767  * cpufreq_register_driver - register a CPU Frequency driver
1768  * @driver_data: A struct cpufreq_driver containing the values#
1769  * submitted by the CPU Frequency driver.
1770  *
1771  *   Registers a CPU Frequency driver to this core code. This code
1772  * returns zero on success, -EBUSY when another driver got here first
1773  * (and isn't unregistered in the meantime).
1774  *
1775  */
1776 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1777 {
1778         unsigned long flags;
1779         int ret;
1780
1781         if (!driver_data || !driver_data->verify || !driver_data->init ||
1782             ((!driver_data->setpolicy) && (!driver_data->target)))
1783                 return -EINVAL;
1784
1785         dprintk("trying to register driver %s\n", driver_data->name);
1786
1787         if (driver_data->setpolicy)
1788                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1789
1790         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1791         if (cpufreq_driver) {
1792                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1793                 return -EBUSY;
1794         }
1795         cpufreq_driver = driver_data;
1796         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1797
1798         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1799
1800         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1801                 int i;
1802                 ret = -ENODEV;
1803
1804                 /* check for at least one working CPU */
1805                 for (i=0; i<NR_CPUS; i++)
1806                         if (cpufreq_cpu_data[i])
1807                                 ret = 0;
1808
1809                 /* if all ->init() calls failed, unregister */
1810                 if (ret) {
1811                         dprintk("no CPU initialized for driver %s\n",
1812                                                         driver_data->name);
1813                         sysdev_driver_unregister(&cpu_sysdev_class,
1814                                                 &cpufreq_sysdev_driver);
1815
1816                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1817                         cpufreq_driver = NULL;
1818                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1819                 }
1820         }
1821
1822         if (!ret) {
1823                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1824                 dprintk("driver %s up and running\n", driver_data->name);
1825                 cpufreq_debug_enable_ratelimit();
1826         }
1827
1828         return (ret);
1829 }
1830 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1831
1832
1833 /**
1834  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1835  *
1836  *    Unregister the current CPUFreq driver. Only call this if you have
1837  * the right to do so, i.e. if you have succeeded in initialising before!
1838  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1839  * currently not initialised.
1840  */
1841 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1842 {
1843         unsigned long flags;
1844
1845         cpufreq_debug_disable_ratelimit();
1846
1847         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1848                 cpufreq_debug_enable_ratelimit();
1849                 return -EINVAL;
1850         }
1851
1852         dprintk("unregistering driver %s\n", driver->name);
1853
1854         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1855         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1856
1857         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1858         cpufreq_driver = NULL;
1859         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1860
1861         return 0;
1862 }
1863 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1864
1865 static int __init cpufreq_core_init(void)
1866 {
1867         int cpu;
1868
1869         for_each_possible_cpu(cpu) {
1870                 per_cpu(policy_cpu, cpu) = -1;
1871                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1872         }
1873         return 0;
1874 }
1875
1876 core_initcall(cpufreq_core_init);