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         struct cpufreq_governor *gov = CPUFREQ_PERFORMANCE_GOVERNOR;
1488
1489         if (policy->governor->max_transition_latency &&
1490             policy->cpuinfo.transition_latency >
1491             policy->governor->max_transition_latency) {
1492                 printk(KERN_WARNING "%s governor failed, too long"
1493                        " transition latency of HW, fallback"
1494                        " to %s governor\n",
1495                        policy->governor->name,
1496                        gov->name);
1497                        policy->governor = gov;
1498         }
1499
1500         if (!try_module_get(policy->governor->owner))
1501                 return -EINVAL;
1502
1503         dprintk("__cpufreq_governor for CPU %u, event %u\n",
1504                                                 policy->cpu, event);
1505         ret = policy->governor->governor(policy, event);
1506
1507         /* we keep one module reference alive for
1508                         each CPU governed by this CPU */
1509         if ((event != CPUFREQ_GOV_START) || ret)
1510                 module_put(policy->governor->owner);
1511         if ((event == CPUFREQ_GOV_STOP) && !ret)
1512                 module_put(policy->governor->owner);
1513
1514         return ret;
1515 }
1516
1517
1518 int cpufreq_register_governor(struct cpufreq_governor *governor)
1519 {
1520         int err;
1521
1522         if (!governor)
1523                 return -EINVAL;
1524
1525         mutex_lock(&cpufreq_governor_mutex);
1526
1527         err = -EBUSY;
1528         if (__find_governor(governor->name) == NULL) {
1529                 err = 0;
1530                 list_add(&governor->governor_list, &cpufreq_governor_list);
1531         }
1532
1533         mutex_unlock(&cpufreq_governor_mutex);
1534         return err;
1535 }
1536 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1537
1538
1539 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1540 {
1541         if (!governor)
1542                 return;
1543
1544         mutex_lock(&cpufreq_governor_mutex);
1545         list_del(&governor->governor_list);
1546         mutex_unlock(&cpufreq_governor_mutex);
1547         return;
1548 }
1549 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1550
1551
1552
1553 /*********************************************************************
1554  *                          POLICY INTERFACE                         *
1555  *********************************************************************/
1556
1557 /**
1558  * cpufreq_get_policy - get the current cpufreq_policy
1559  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1560  *
1561  * Reads the current cpufreq policy.
1562  */
1563 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1564 {
1565         struct cpufreq_policy *cpu_policy;
1566         if (!policy)
1567                 return -EINVAL;
1568
1569         cpu_policy = cpufreq_cpu_get(cpu);
1570         if (!cpu_policy)
1571                 return -EINVAL;
1572
1573         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1574
1575         cpufreq_cpu_put(cpu_policy);
1576         return 0;
1577 }
1578 EXPORT_SYMBOL(cpufreq_get_policy);
1579
1580
1581 /*
1582  * data   : current policy.
1583  * policy : policy to be set.
1584  */
1585 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1586                                 struct cpufreq_policy *policy)
1587 {
1588         int ret = 0;
1589
1590         cpufreq_debug_disable_ratelimit();
1591         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1592                 policy->min, policy->max);
1593
1594         memcpy(&policy->cpuinfo, &data->cpuinfo,
1595                                 sizeof(struct cpufreq_cpuinfo));
1596
1597         if (policy->min > data->min && policy->min > policy->max) {
1598                 ret = -EINVAL;
1599                 goto error_out;
1600         }
1601
1602         /* verify the cpu speed can be set within this limit */
1603         ret = cpufreq_driver->verify(policy);
1604         if (ret)
1605                 goto error_out;
1606
1607         /* adjust if necessary - all reasons */
1608         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1609                         CPUFREQ_ADJUST, policy);
1610
1611         /* adjust if necessary - hardware incompatibility*/
1612         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1613                         CPUFREQ_INCOMPATIBLE, policy);
1614
1615         /* verify the cpu speed can be set within this limit,
1616            which might be different to the first one */
1617         ret = cpufreq_driver->verify(policy);
1618         if (ret)
1619                 goto error_out;
1620
1621         /* notification of the new policy */
1622         blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1623                         CPUFREQ_NOTIFY, policy);
1624
1625         data->min = policy->min;
1626         data->max = policy->max;
1627
1628         dprintk("new min and max freqs are %u - %u kHz\n",
1629                                         data->min, data->max);
1630
1631         if (cpufreq_driver->setpolicy) {
1632                 data->policy = policy->policy;
1633                 dprintk("setting range\n");
1634                 ret = cpufreq_driver->setpolicy(policy);
1635         } else {
1636                 if (policy->governor != data->governor) {
1637                         /* save old, working values */
1638                         struct cpufreq_governor *old_gov = data->governor;
1639
1640                         dprintk("governor switch\n");
1641
1642                         /* end old governor */
1643                         if (data->governor)
1644                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1645
1646                         /* start new governor */
1647                         data->governor = policy->governor;
1648                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1649                                 /* new governor failed, so re-start old one */
1650                                 dprintk("starting governor %s failed\n",
1651                                                         data->governor->name);
1652                                 if (old_gov) {
1653                                         data->governor = old_gov;
1654                                         __cpufreq_governor(data,
1655                                                            CPUFREQ_GOV_START);
1656                                 }
1657                                 ret = -EINVAL;
1658                                 goto error_out;
1659                         }
1660                         /* might be a policy change, too, so fall through */
1661                 }
1662                 dprintk("governor: change or update limits\n");
1663                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1664         }
1665
1666 error_out:
1667         cpufreq_debug_enable_ratelimit();
1668         return ret;
1669 }
1670
1671 /**
1672  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1673  *      @cpu: CPU which shall be re-evaluated
1674  *
1675  *      Usefull for policy notifiers which have different necessities
1676  *      at different times.
1677  */
1678 int cpufreq_update_policy(unsigned int cpu)
1679 {
1680         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1681         struct cpufreq_policy policy;
1682         int ret = 0;
1683
1684         if (!data)
1685                 return -ENODEV;
1686
1687         if (unlikely(lock_policy_rwsem_write(cpu)))
1688                 return -EINVAL;
1689
1690         dprintk("updating policy for CPU %u\n", cpu);
1691         memcpy(&policy, data, sizeof(struct cpufreq_policy));
1692         policy.min = data->user_policy.min;
1693         policy.max = data->user_policy.max;
1694         policy.policy = data->user_policy.policy;
1695         policy.governor = data->user_policy.governor;
1696
1697         /* BIOS might change freq behind our back
1698           -> ask driver for current freq and notify governors about a change */
1699         if (cpufreq_driver->get) {
1700                 policy.cur = cpufreq_driver->get(cpu);
1701                 if (!data->cur) {
1702                         dprintk("Driver did not initialize current freq");
1703                         data->cur = policy.cur;
1704                 } else {
1705                         if (data->cur != policy.cur)
1706                                 cpufreq_out_of_sync(cpu, data->cur,
1707                                                                 policy.cur);
1708                 }
1709         }
1710
1711         ret = __cpufreq_set_policy(data, &policy);
1712
1713         unlock_policy_rwsem_write(cpu);
1714
1715         cpufreq_cpu_put(data);
1716         return ret;
1717 }
1718 EXPORT_SYMBOL(cpufreq_update_policy);
1719
1720 static int cpufreq_cpu_callback(struct notifier_block *nfb,
1721                                         unsigned long action, void *hcpu)
1722 {
1723         unsigned int cpu = (unsigned long)hcpu;
1724         struct sys_device *sys_dev;
1725
1726         sys_dev = get_cpu_sysdev(cpu);
1727         if (sys_dev) {
1728                 switch (action) {
1729                 case CPU_ONLINE:
1730                 case CPU_ONLINE_FROZEN:
1731                         cpufreq_add_dev(sys_dev);
1732                         break;
1733                 case CPU_DOWN_PREPARE:
1734                 case CPU_DOWN_PREPARE_FROZEN:
1735                         if (unlikely(lock_policy_rwsem_write(cpu)))
1736                                 BUG();
1737
1738                         __cpufreq_remove_dev(sys_dev);
1739                         break;
1740                 case CPU_DOWN_FAILED:
1741                 case CPU_DOWN_FAILED_FROZEN:
1742                         cpufreq_add_dev(sys_dev);
1743                         break;
1744                 }
1745         }
1746         return NOTIFY_OK;
1747 }
1748
1749 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1750 {
1751     .notifier_call = cpufreq_cpu_callback,
1752 };
1753
1754 /*********************************************************************
1755  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1756  *********************************************************************/
1757
1758 /**
1759  * cpufreq_register_driver - register a CPU Frequency driver
1760  * @driver_data: A struct cpufreq_driver containing the values#
1761  * submitted by the CPU Frequency driver.
1762  *
1763  *   Registers a CPU Frequency driver to this core code. This code
1764  * returns zero on success, -EBUSY when another driver got here first
1765  * (and isn't unregistered in the meantime).
1766  *
1767  */
1768 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1769 {
1770         unsigned long flags;
1771         int ret;
1772
1773         if (!driver_data || !driver_data->verify || !driver_data->init ||
1774             ((!driver_data->setpolicy) && (!driver_data->target)))
1775                 return -EINVAL;
1776
1777         dprintk("trying to register driver %s\n", driver_data->name);
1778
1779         if (driver_data->setpolicy)
1780                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1781
1782         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1783         if (cpufreq_driver) {
1784                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1785                 return -EBUSY;
1786         }
1787         cpufreq_driver = driver_data;
1788         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1789
1790         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1791
1792         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1793                 int i;
1794                 ret = -ENODEV;
1795
1796                 /* check for at least one working CPU */
1797                 for (i=0; i<NR_CPUS; i++)
1798                         if (cpufreq_cpu_data[i])
1799                                 ret = 0;
1800
1801                 /* if all ->init() calls failed, unregister */
1802                 if (ret) {
1803                         dprintk("no CPU initialized for driver %s\n",
1804                                                         driver_data->name);
1805                         sysdev_driver_unregister(&cpu_sysdev_class,
1806                                                 &cpufreq_sysdev_driver);
1807
1808                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1809                         cpufreq_driver = NULL;
1810                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1811                 }
1812         }
1813
1814         if (!ret) {
1815                 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1816                 dprintk("driver %s up and running\n", driver_data->name);
1817                 cpufreq_debug_enable_ratelimit();
1818         }
1819
1820         return (ret);
1821 }
1822 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1823
1824
1825 /**
1826  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1827  *
1828  *    Unregister the current CPUFreq driver. Only call this if you have
1829  * the right to do so, i.e. if you have succeeded in initialising before!
1830  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1831  * currently not initialised.
1832  */
1833 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1834 {
1835         unsigned long flags;
1836
1837         cpufreq_debug_disable_ratelimit();
1838
1839         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1840                 cpufreq_debug_enable_ratelimit();
1841                 return -EINVAL;
1842         }
1843
1844         dprintk("unregistering driver %s\n", driver->name);
1845
1846         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1847         unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1848
1849         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1850         cpufreq_driver = NULL;
1851         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1852
1853         return 0;
1854 }
1855 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1856
1857 static int __init cpufreq_core_init(void)
1858 {
1859         int cpu;
1860
1861         for_each_possible_cpu(cpu) {
1862                 per_cpu(policy_cpu, cpu) = -1;
1863                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1864         }
1865         return 0;
1866 }
1867
1868 core_initcall(cpufreq_core_init);