git.oblomov.eu Git - linux-2.6/blob - 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                 if (unlikely(lock_policy_rwsem_read(cpu)))
1115                         return ret_freq;
1116
1117                 ret_freq = policy->cur;
1118
1119                 unlock_policy_rwsem_read(cpu);
1120                 cpufreq_cpu_put(policy);
1121         }
1122
1123         return (ret_freq);
1124 }
1125 EXPORT_SYMBOL(cpufreq_quick_get);
1126
1127
1128 static unsigned int __cpufreq_get(unsigned int cpu)
1129 {
1130         struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1131         unsigned int ret_freq = 0;
1132
1133         if (!cpufreq_driver->get)
1134                 return (ret_freq);
1135
1136         ret_freq = cpufreq_driver->get(cpu);
1137
1138         if (ret_freq && policy->cur &&
1139                 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1140                 /* verify no discrepancy between actual and
1141                                         saved value exists */
1142                 if (unlikely(ret_freq != policy->cur)) {
1143                         cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1144                         schedule_work(&policy->update);
1145                 }
1146         }
1147
1148         return (ret_freq);
1149 }
1150
1151 /**
1152  * cpufreq_get - get the current CPU frequency (in kHz)
1153  * @cpu: CPU number
1154  *
1155  * Get the CPU current (static) CPU frequency
1156  */
1157 unsigned int cpufreq_get(unsigned int cpu)
1158 {
1159         unsigned int ret_freq = 0;
1160         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1161
1162         if (!policy)
1163                 goto out;
1164
1165         if (unlikely(lock_policy_rwsem_read(cpu)))
1166                 goto out_policy;
1167
1168         ret_freq = __cpufreq_get(cpu);
1169
1170         unlock_policy_rwsem_read(cpu);
1171
1172 out_policy:
1173         cpufreq_cpu_put(policy);
1174 out:
1175         return (ret_freq);
1176 }
1177 EXPORT_SYMBOL(cpufreq_get);
1178
1179
1180 /**
1181  *      cpufreq_suspend - let the low level driver prepare for suspend
1182  */
1183
1184 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
1185 {
1186         int cpu = sysdev->id;
1187         int ret = 0;
1188         unsigned int cur_freq = 0;
1189         struct cpufreq_policy *cpu_policy;
1190
1191         dprintk("suspending cpu %u\n", cpu);
1192
1193         if (!cpu_online(cpu))
1194                 return 0;
1195
1196         /* we may be lax here as interrupts are off. Nonetheless
1197          * we need to grab the correct cpu policy, as to check
1198          * whether we really run on this CPU.
1199          */
1200
1201         cpu_policy = cpufreq_cpu_get(cpu);
1202         if (!cpu_policy)
1203                 return -EINVAL;
1204
1205         /* only handle each CPU group once */
1206         if (unlikely(cpu_policy->cpu != cpu)) {
1207                 cpufreq_cpu_put(cpu_policy);
1208                 return 0;
1209         }
1210
1211         if (cpufreq_driver->suspend) {
1212                 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1213                 if (ret) {
1214                         printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1215                                         "step on CPU %u\n", cpu_policy->cpu);
1216                         cpufreq_cpu_put(cpu_policy);
1217                         return ret;
1218                 }
1219         }
1220
1221
1222         if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1223                 goto out;
1224
1225         if (cpufreq_driver->get)
1226                 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1227
1228         if (!cur_freq || !cpu_policy->cur) {
1229                 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1230                        "frequency is what timing core thinks it is.\n");
1231                 goto out;
1232         }
1233
1234         if (unlikely(cur_freq != cpu_policy->cur)) {
1235                 struct cpufreq_freqs freqs;
1236
1237                 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1238                         dprintk("Warning: CPU frequency is %u, "
1239                                "cpufreq assumed %u kHz.\n",
1240                                cur_freq, cpu_policy->cur);
1241
1242                 freqs.cpu = cpu;
1243                 freqs.old = cpu_policy->cur;
1244                 freqs.new = cur_freq;
1245
1246                 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1247                                     CPUFREQ_SUSPENDCHANGE, &freqs);
1248                 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1249
1250                 cpu_policy->cur = cur_freq;
1251         }
1252
1253 out:
1254         cpufreq_cpu_put(cpu_policy);
1255         return 0;
1256 }
1257
1258 /**
1259  *      cpufreq_resume -  restore proper CPU frequency handling after resume
1260  *
1261  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1262  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1263  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1264  *          restored.
1265  */
1266 static int cpufreq_resume(struct sys_device * sysdev)
1267 {
1268         int cpu = sysdev->id;
1269         int ret = 0;
1270         struct cpufreq_policy *cpu_policy;
1271
1272         dprintk("resuming cpu %u\n", cpu);
1273
1274         if (!cpu_online(cpu))
1275                 return 0;
1276
1277         /* we may be lax here as interrupts are off. Nonetheless
1278          * we need to grab the correct cpu policy, as to check
1279          * whether we really run on this CPU.
1280          */
1281
1282         cpu_policy = cpufreq_cpu_get(cpu);
1283         if (!cpu_policy)
1284                 return -EINVAL;
1285
1286         /* only handle each CPU group once */
1287         if (unlikely(cpu_policy->cpu != cpu)) {
1288                 cpufreq_cpu_put(cpu_policy);
1289                 return 0;
1290         }
1291
1292         if (cpufreq_driver->resume) {
1293                 ret = cpufreq_driver->resume(cpu_policy);
1294                 if (ret) {
1295                         printk(KERN_ERR "cpufreq: resume failed in ->resume "
1296                                         "step on CPU %u\n", cpu_policy->cpu);
1297                         cpufreq_cpu_put(cpu_policy);
1298                         return ret;
1299                 }
1300         }
1301
1302         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1303                 unsigned int cur_freq = 0;
1304
1305                 if (cpufreq_driver->get)
1306                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1307
1308                 if (!cur_freq || !cpu_policy->cur) {
1309                         printk(KERN_ERR "cpufreq: resume failed to assert "
1310                                         "current frequency is what timing core "
1311                                         "thinks it is.\n");
1312                         goto out;
1313                 }
1314
1315                 if (unlikely(cur_freq != cpu_policy->cur)) {
1316                         struct cpufreq_freqs freqs;
1317
1318                         if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1319                                 dprintk("Warning: CPU frequency"
1320                                        "is %u, cpufreq assumed %u kHz.\n",
1321                                        cur_freq, cpu_policy->cur);
1322
1323                         freqs.cpu = cpu;
1324                         freqs.old = cpu_policy->cur;
1325                         freqs.new = cur_freq;
1326
1327                         srcu_notifier_call_chain(
1328                                         &cpufreq_transition_notifier_list,
1329                                         CPUFREQ_RESUMECHANGE, &freqs);
1330                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1331
1332                         cpu_policy->cur = cur_freq;
1333                 }
1334         }
1335
1336 out:
1337         schedule_work(&cpu_policy->update);
1338         cpufreq_cpu_put(cpu_policy);
1339         return ret;
1340 }
1341
1342 static struct sysdev_driver cpufreq_sysdev_driver = {
1343         .add            = cpufreq_add_dev,
1344         .remove         = cpufreq_remove_dev,
1345         .suspend        = cpufreq_suspend,
1346         .resume         = cpufreq_resume,
1347 };
1348
1349
1350 /*********************************************************************
1351  *                     NOTIFIER LISTS INTERFACE                      *
1352  *********************************************************************/
1353
1354 /**
1355  *      cpufreq_register_notifier - register a driver with cpufreq
1356  *      @nb: notifier function to register
1357  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1358  *
1359  *      Add a driver to one of two lists: either a list of drivers that
1360  *      are notified about clock rate changes (once before and once after
1361  *      the transition), or a list of drivers that are notified about
1362  *      changes in cpufreq policy.
1363  *
1364  *      This function may sleep, and has the same return conditions as
1365  *      blocking_notifier_chain_register.
1366  */
1367 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1368 {
1369         int ret;
1370
1371         switch (list) {
1372         case CPUFREQ_TRANSITION_NOTIFIER:
1373                 ret = srcu_notifier_chain_register(
1374                                 &cpufreq_transition_notifier_list, nb);
1375                 break;
1376         case CPUFREQ_POLICY_NOTIFIER:
1377                 ret = blocking_notifier_chain_register(
1378                                 &cpufreq_policy_notifier_list, nb);
1379                 break;
1380         default:
1381                 ret = -EINVAL;
1382         }
1383
1384         return ret;
1385 }
1386 EXPORT_SYMBOL(cpufreq_register_notifier);
1387
1388
1389 /**
1390  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
1391  *      @nb: notifier block to be unregistered
1392  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1393  *
1394  *      Remove a driver from the CPU frequency notifier list.
1395  *
1396  *      This function may sleep, and has the same return conditions as
1397  *      blocking_notifier_chain_unregister.
1398  */
1399 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1400 {
1401         int ret;
1402
1403         switch (list) {
1404         case CPUFREQ_TRANSITION_NOTIFIER:
1405                 ret = srcu_notifier_chain_unregister(
1406                                 &cpufreq_transition_notifier_list, nb);
1407                 break;
1408         case CPUFREQ_POLICY_NOTIFIER:
1409                 ret = blocking_notifier_chain_unregister(
1410                                 &cpufreq_policy_notifier_list, nb);
1411                 break;
1412         default:
1413                 ret = -EINVAL;
1414         }
1415
1416         return ret;
1417 }
1418 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1419
1420
1421 /*********************************************************************
1422  *                              GOVERNORS                            *
1423  *********************************************************************/
1424
1425
1426 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1427                             unsigned int target_freq,
1428                             unsigned int relation)
1429 {
1430         int retval = -EINVAL;
1431
1432         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1433                 target_freq, relation);
1434         if (cpu_online(policy->cpu) && cpufreq_driver->target)
1435                 retval = cpufreq_driver->target(policy, target_freq, relation);
1436
1437         return retval;
1438 }
1439 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1440
1441 int cpufreq_driver_target(struct cpufreq_policy *policy,
1442                           unsigned int target_freq,
1443                           unsigned int relation)
1444 {
1445         int ret;
1446
1447         policy = cpufreq_cpu_get(policy->cpu);
1448         if (!policy)
1449                 return -EINVAL;
1450
1451         if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1452                 return -EINVAL;
1453
1454         ret = __cpufreq_driver_target(policy, target_freq, relation);
1455
1456         unlock_policy_rwsem_write(policy->cpu);
1457
1458         cpufreq_cpu_put(policy);
1459         return ret;
1460 }
1461 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1462
1463 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1464 {
1465         int ret = 0;
1466
1467         policy = cpufreq_cpu_get(policy->cpu);
1468         if (!policy)
1469                 return -EINVAL;
1470
1471         if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1472                 ret = cpufreq_driver->getavg(policy->cpu);
1473
1474         cpufreq_cpu_put(policy);
1475         return ret;
1476 }
1477 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1478
1479 /*
1480  * when "event" is CPUFREQ_GOV_LIMITS
1481  */
1482
1483 static int __cpufreq_governor(struct cpufreq_policy *policy,
1484                                         unsigned int event)
1485 {
1486         int ret;
1487
1488         /* Only must be defined when default governor is known to have latency
1489            restrictions, like e.g. conservative or ondemand.
1490            That this is the case is already ensured in Kconfig
1491         */
1492 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1493         struct cpufreq_governor *gov = &cpufreq_gov_performance;
1494 #else
1495         struct cpufreq_governor *gov = NULL;
1496 #endif
1497
1498         if (policy->governor->max_transition_latency &&
1499             policy->cpuinfo.transition_latency >
1500             policy->governor->max_transition_latency) {
1501                 if (!gov)
1502                         return -EINVAL;
1503                 else {
1504                         printk(KERN_WARNING "%s governor failed, too long"
1505                                " transition latency of HW, fallback"
1506                                " to %s governor\n",
1507                                policy->governor->name,
1508                                gov->name);
1509                         policy->governor = gov;
1510                 }
1511         }
1512
1513         if (!try_module_get(policy->governor->owner))
1514                 return -EINVAL;
1515
1516         dprintk("__cpufreq_governor for CPU %u, event %u\n",
1517                                                 policy->cpu, event);
1518         ret = policy->governor->governor(policy, event);
1519
1520         /* we keep one module reference alive for
1521                         each CPU governed by this CPU */
1522         if ((event != CPUFREQ_GOV_START) || ret)
1523                 module_put(policy->governor->owner);
1524         if ((event == CPUFREQ_GOV_STOP) && !ret)
1525                 module_put(policy->governor->owner);
1526
1527         return ret;
1528 }
1529
1530
1531 int cpufreq_register_governor(struct cpufreq_governor *governor)
1532 {
1533         int err;
1534
1535         if (!governor)
1536                 return -EINVAL;
1537
1538         mutex_lock(&cpufreq_governor_mutex);
1539
1540         err = -EBUSY;
1541         if (__find_governor(governor->name) == NULL) {
1542                 err = 0;
1543                 list_add(&governor->governor_list, &cpufreq_governor_list);
1544         }
1545
1546         mutex_unlock(&cpufreq_governor_mutex);
1547         return err;
1548 }
1549 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1550
1551
1552 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1553 {
1554         if (!governor)
1555                 return;
1556
1557         mutex_lock(&cpufreq_governor_mutex);
1558         list_del(&governor->governor_list);
1559         mutex_unlock(&cpufreq_governor_mutex);
1560         return;
1561 }
1562 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1563
1564
1565
1566 /*********************************************************************
1567  *                          POLICY INTERFACE                         *
1568  *********************************************************************/
1569
1570 /**
1571  * cpufreq_get_policy - get the current cpufreq_policy
1572  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1573  *
1574  * Reads the current cpufreq policy.
1575  */
1576 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1577 {
1578         struct cpufreq_policy *cpu_policy;
1579         if (!policy)
1580                 return -EINVAL;
1581
1582         cpu_policy = cpufreq_cpu_get(cpu);
1583         if (!cpu_policy)
1584                 return -EINVAL;
1585
1586         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1587
1588         cpufreq_cpu_put(cpu_policy);
1589         return 0;
1590 }
1591 EXPORT_SYMBOL(cpufreq_get_policy);
1592
1593
1594 /*
1595  * data   : current policy.
1596  * policy : policy to be set.
1597  */
1598 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1599                                 struct cpufreq_policy *policy)
1600 {
1601         int ret = 0;
1602
1603         cpufreq_debug_disable_ratelimit();
1604         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1605                 policy->min, policy->max);
1606
1607         memcpy(&policy->cpuinfo, &data->cpuinfo,
1608                                 sizeof(struct cpufreq_cpuinfo));
1609
1610         if (policy->min > data->min && policy->min > policy->max) {
1611                 ret = -EINVAL;
1612                 goto error_out;
1613         }
1614
1615         /* verify the cpu speed can be set within this limit */
1616         ret = cpufreq_driver->verify(policy);
1617         if (ret)
1618                 goto error_out;
1619
1620         /* adjust if necessary - all reasons */
1621         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1622                         CPUFREQ_ADJUST, policy);
1623
1624         /* adjust if necessary - hardware incompatibility*/
1625         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1626                         CPUFREQ_INCOMPATIBLE, policy);
1627
1628         /* verify the cpu speed can be set within this limit,
1629            which might be different to the first one */
1630         ret = cpufreq_driver->verify(policy);
1631         if (ret)
1632                 goto error_out;
1633
1634         /* notification of the new policy */
1635         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1636                         CPUFREQ_NOTIFY, policy);
1637
1638         data->min = policy->min;
1639         data->max = policy->max;
1640
1641         dprintk("new min and max freqs are %u - %u kHz\n",
1642                                         data->min, data->max);
1643
1644         if (cpufreq_driver->setpolicy) {
1645                 data->policy = policy->policy;
1646                 dprintk("setting range\n");
1647                 ret = cpufreq_driver->setpolicy(policy);
1648         } else {
1649                 if (policy->governor != data->governor) {
1650                         /* save old, working values */
1651                         struct cpufreq_governor *old_gov = data->governor;
1652
1653                         dprintk("governor switch\n");
1654
1655                         /* end old governor */
1656                         if (data->governor)
1657                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1658
1659                         /* start new governor */
1660                         data->governor = policy->governor;
1661                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1662                                 /* new governor failed, so re-start old one */
1663                                 dprintk("starting governor %s failed\n",
1664                                                         data->governor->name);
1665                                 if (old_gov) {
1666                                         data->governor = old_gov;
1667                                         __cpufreq_governor(data,
1668                                                            CPUFREQ_GOV_START);
1669                                 }
1670                                 ret = -EINVAL;
1671                                 goto error_out;
1672                         }
1673                         /* might be a policy change, too, so fall through */
1674                 }
1675                 dprintk("governor: change or update limits\n");
1676                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1677         }
1678
1679 error_out:
1680         cpufreq_debug_enable_ratelimit();
1681         return ret;
1682 }
1683
1684 /**
1685  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1686  *      @cpu: CPU which shall be re-evaluated
1687  *
1688  *      Usefull for policy notifiers which have different necessities
1689  *      at different times.
1690  */
1691 int cpufreq_update_policy(unsigned int cpu)
1692 {
1693         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1694         struct cpufreq_policy policy;
1695         int ret = 0;
1696
1697         if (!data)
1698                 return -ENODEV;
1699
1700         if (unlikely(lock_policy_rwsem_write(cpu)))
1701                 return -EINVAL;
1702
1703         dprintk("updating policy for CPU %u\n", cpu);
1704         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1705         policy.min = data->user_policy.min;
1706         policy.max = data->user_policy.max;
1707         policy.policy = data->user_policy.policy;
1708         policy.governor = data->user_policy.governor;
1709
1710         /* BIOS might change freq behind our back
1711           -> ask driver for current freq and notify governors about a change */
1712         if (cpufreq_driver->get) {
1713                 policy.cur = cpufreq_driver->get(cpu);
1714                 if (!data->cur) {
1715                         dprintk("Driver did not initialize current freq");
1716                         data->cur = policy.cur;
1717                 } else {
1718                         if (data->cur != policy.cur)
1719                                 cpufreq_out_of_sync(cpu, data->cur,
1720                                                                 policy.cur);
1721                 }
1722         }
1723
1724         ret = __cpufreq_set_policy(data, &policy);
1725
1726         unlock_policy_rwsem_write(cpu);
1727
1728         cpufreq_cpu_put(data);
1729         return ret;
1730 }
1731 EXPORT_SYMBOL(cpufreq_update_policy);
1732
1733 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1734                                         unsigned long action, void *hcpu)
1735 {
1736         unsigned int cpu = (unsigned long)hcpu;
1737         struct sys_device *sys_dev;
1738
1739         sys_dev = get_cpu_sysdev(cpu);
1740         if (sys_dev) {
1741                 switch (action) {
1742                 case CPU_ONLINE:
1743                 case CPU_ONLINE_FROZEN:
1744                         cpufreq_add_dev(sys_dev);
1745                         break;
1746                 case CPU_DOWN_PREPARE:
1747                 case CPU_DOWN_PREPARE_FROZEN:
1748                         if (unlikely(lock_policy_rwsem_write(cpu)))
1749                                 BUG();
1750
1751                         __cpufreq_remove_dev(sys_dev);
1752                         break;
1753                 case CPU_DOWN_FAILED:
1754                 case CPU_DOWN_FAILED_FROZEN:
1755                         cpufreq_add_dev(sys_dev);
1756                         break;
1757                 }
1758         }
1759         return NOTIFY_OK;
1760 }
1761
1762 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1763 {
1764     .notifier_call = cpufreq_cpu_callback,
1765 };
1766
1767 /*********************************************************************
1768  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1769  *********************************************************************/
1770
1771 /**
1772  * cpufreq_register_driver - register a CPU Frequency driver
1773  * @driver_data: A struct cpufreq_driver containing the values#
1774  * submitted by the CPU Frequency driver.
1775  *
1776  *   Registers a CPU Frequency driver to this core code. This code
1777  * returns zero on success, -EBUSY when another driver got here first
1778  * (and isn't unregistered in the meantime).
1779  *
1780  */
1781 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1782 {
1783         unsigned long flags;
1784         int ret;
1785
1786         if (!driver_data || !driver_data->verify || !driver_data->init ||
1787             ((!driver_data->setpolicy) && (!driver_data->target)))
1788                 return -EINVAL;
1789
1790         dprintk("trying to register driver %s\n", driver_data->name);
1791
1792         if (driver_data->setpolicy)
1793                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1794
1795         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1796         if (cpufreq_driver) {
1797                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1798                 return -EBUSY;
1799         }
1800         cpufreq_driver = driver_data;
1801         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1802
1803         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1804
1805         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1806                 int i;
1807                 ret = -ENODEV;
1808
1809                 /* check for at least one working CPU */
1810                 for (i=0; i<NR_CPUS; i++)
1811                         if (cpufreq_cpu_data[i])
1812                                 ret = 0;
1813
1814                 /* if all ->init() calls failed, unregister */
1815                 if (ret) {
1816                         dprintk("no CPU initialized for driver %s\n",
1817                                                         driver_data->name);
1818                         sysdev_driver_unregister(&cpu_sysdev_class,
1819                                                 &cpufreq_sysdev_driver);
1820
1821                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1822                         cpufreq_driver = NULL;
1823                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1824                 }
1825         }
1826
1827         if (!ret) {
1828                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1829                 dprintk("driver %s up and running\n", driver_data->name);
1830                 cpufreq_debug_enable_ratelimit();
1831         }
1832
1833         return (ret);
1834 }
1835 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1836
1837
1838 /**
1839  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1840  *
1841  *    Unregister the current CPUFreq driver. Only call this if you have
1842  * the right to do so, i.e. if you have succeeded in initialising before!
1843  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1844  * currently not initialised.
1845  */
1846 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1847 {
1848         unsigned long flags;
1849
1850         cpufreq_debug_disable_ratelimit();
1851
1852         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1853                 cpufreq_debug_enable_ratelimit();
1854                 return -EINVAL;
1855         }
1856
1857         dprintk("unregistering driver %s\n", driver->name);
1858
1859         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1860         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1861
1862         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1863         cpufreq_driver = NULL;
1864         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1865
1866         return 0;
1867 }
1868 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1869
1870 static int __init cpufreq_core_init(void)
1871 {
1872         int cpu;
1873
1874         for_each_possible_cpu(cpu) {
1875                 per_cpu(policy_cpu, cpu) = -1;
1876                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1877         }
1878         return 0;
1879 }
1880
1881 core_initcall(cpufreq_core_init);