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  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/notifier.h>
  18 #include <linux/cpufreq.h>
  19 #include <linux/delay.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/device.h>
  23 #include <linux/slab.h>
  24 #include <linux/cpu.h>
  25 #include <linux/completion.h>
  26
  27 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
  28
  29 /**
  30  * The "cpufreq driver" - the arch- or hardware-dependend low
  31  * level driver of CPUFreq support, and its spinlock. This lock
  32  * also protects the cpufreq_cpu_data array.
  33  */
  34 static struct cpufreq_driver    *cpufreq_driver;
  35 static struct cpufreq_policy    *cpufreq_cpu_data[NR_CPUS];
  36 static spinlock_t               cpufreq_driver_lock = SPIN_LOCK_UNLOCKED;
  37
  38
  39 /* we keep a copy of all ->add'ed CPU's struct sys_device here;
  40  * as it is only accessed in ->add and ->remove, no lock or reference
  41  * count is necessary.
  42  */
  43 static struct sys_device        *cpu_sys_devices[NR_CPUS];
  44
  45
  46 /* internal prototypes */
  47 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
  48 static void handle_update(void *data);
  49 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci);
  50
  51 /**
  52  * Two notifier lists: the "policy" list is involved in the
  53  * validation process for a new CPU frequency policy; the
  54  * "transition" list for kernel code that needs to handle
  55  * changes to devices when the CPU clock speed changes.
  56  * The mutex locks both lists.
  57  */
  58 static struct notifier_block    *cpufreq_policy_notifier_list;
  59 static struct notifier_block    *cpufreq_transition_notifier_list;
  60 static DECLARE_RWSEM            (cpufreq_notifier_rwsem);
  61
  62
  63 static LIST_HEAD(cpufreq_governor_list);
  64 static DECLARE_MUTEX            (cpufreq_governor_sem);
  65
  66 static struct cpufreq_policy * cpufreq_cpu_get(unsigned int cpu)
  67 {
  68         struct cpufreq_policy *data;
  69         unsigned long flags;
  70
  71         if (cpu >= NR_CPUS)
  72                 goto err_out;
  73
  74         /* get the cpufreq driver */
  75         spin_lock_irqsave(&cpufreq_driver_lock, flags);
  76
  77         if (!cpufreq_driver)
  78                 goto err_out_unlock;
  79
  80         if (!try_module_get(cpufreq_driver->owner))
  81                 goto err_out_unlock;
  82
  83
  84         /* get the CPU */
  85         data = cpufreq_cpu_data[cpu];
  86
  87         if (!data)
  88                 goto err_out_put_module;
  89
  90         if (!kobject_get(&data->kobj))
  91                 goto err_out_put_module;
  92
  93
  94         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
  95
  96         return data;
  97
  98  err_out_put_module:
  99         module_put(cpufreq_driver->owner);
 100  err_out_unlock:
 101         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 102  err_out:
 103         return NULL;
 104 }
 105
 106 static void cpufreq_cpu_put(struct cpufreq_policy *data)
 107 {
 108         kobject_put(&data->kobj);
 109         module_put(cpufreq_driver->owner);
 110 }
 111
 112
 113 /*********************************************************************
 114  *                     UNIFIED DEBUG HELPERS                         *
 115  *********************************************************************/
 116 #ifdef CONFIG_CPU_FREQ_DEBUG
 117
 118 /* what part(s) of the CPUfreq subsystem are debugged? */
 119 static unsigned int debug;
 120
 121 /* is the debug output ratelimit'ed using printk_ratelimit? User can
 122  * set or modify this value.
 123  */
 124 static unsigned int debug_ratelimit = 1;
 125
 126 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
 127  * loading of a cpufreq driver, temporarily disabled when a new policy
 128  * is set, and disabled upon cpufreq driver removal
 129  */
 130 static unsigned int disable_ratelimit = 1;
 131 static spinlock_t disable_ratelimit_lock = SPIN_LOCK_UNLOCKED;
 132
 133 static inline void cpufreq_debug_enable_ratelimit(void)
 134 {
 135         unsigned long flags;
 136
 137         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 138         if (disable_ratelimit)
 139                 disable_ratelimit--;
 140         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 141 }
 142
 143 static inline void cpufreq_debug_disable_ratelimit(void)
 144 {
 145         unsigned long flags;
 146
 147         spin_lock_irqsave(&disable_ratelimit_lock, flags);
 148         disable_ratelimit++;
 149         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 150 }
 151
 152 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
 153 {
 154         char s[256];
 155         va_list args;
 156         unsigned int len;
 157         unsigned long flags;
 158
 159         WARN_ON(!prefix);
 160         if (type & debug) {
 161                 spin_lock_irqsave(&disable_ratelimit_lock, flags);
 162                 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
 163                         spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 164                         return;
 165                 }
 166                 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
 167
 168                 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
 169
 170                 va_start(args, fmt);
 171                 len += vsnprintf(&s[len], (256 - len), fmt, args);
 172                 va_end(args);
 173
 174                 printk(s);
 175
 176                 WARN_ON(len < 5);
 177         }
 178 }
 179 EXPORT_SYMBOL(cpufreq_debug_printk);
 180
 181
 182 module_param(debug, uint, 0644);
 183 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
 184
 185 module_param(debug_ratelimit, uint, 0644);
 186 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
 187
 188 #else /* !CONFIG_CPU_FREQ_DEBUG */
 189
 190 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
 191 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
 192
 193 #endif /* CONFIG_CPU_FREQ_DEBUG */
 194
 195
 196 /*********************************************************************
 197  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
 198  *********************************************************************/
 199
 200 /**
 201  * adjust_jiffies - adjust the system "loops_per_jiffy"
 202  *
 203  * This function alters the system "loops_per_jiffy" for the clock
 204  * speed change. Note that loops_per_jiffy cannot be updated on SMP
 205  * systems as each CPU might be scaled differently. So, use the arch
 206  * per-CPU loops_per_jiffy value wherever possible.
 207  */
 208 #ifndef CONFIG_SMP
 209 static unsigned long l_p_j_ref;
 210 static unsigned int  l_p_j_ref_freq;
 211
 212 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 213 {
 214         if (ci->flags & CPUFREQ_CONST_LOOPS)
 215                 return;
 216
 217         if (!l_p_j_ref_freq) {
 218                 l_p_j_ref = loops_per_jiffy;
 219                 l_p_j_ref_freq = ci->old;
 220                 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 221         }
 222         if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
 223             (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
 224             (val == CPUFREQ_RESUMECHANGE)) {
 225                 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
 226                 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
 227         }
 228 }
 229 #else
 230 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
 231 #endif
 232
 233
 234 /**
 235  * cpufreq_notify_transition - call notifier chain and adjust_jiffies on frequency transition
 236  *
 237  * This function calls the transition notifiers and the "adjust_jiffies" function. It is called
 238  * twice on all CPU frequency changes that have external effects.
 239  */
 240 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 241 {
 242         BUG_ON(irqs_disabled());
 243
 244         freqs->flags = cpufreq_driver->flags;
 245         dprintk("notification %u of frequency transition to %u kHz\n", state, freqs->new);
 246
 247         down_read(&cpufreq_notifier_rwsem);
 248         switch (state) {
 249         case CPUFREQ_PRECHANGE:
 250                 /* detect if the driver reported a value as "old frequency" which
 251                  * is not equal to what the cpufreq core thinks is "old frequency".
 252                  */
 253                 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 254                         if ((likely(cpufreq_cpu_data[freqs->cpu])) &&
 255                             (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)) &&
 256                             (likely(cpufreq_cpu_data[freqs->cpu]->cur)) &&
 257                             (unlikely(freqs->old != cpufreq_cpu_data[freqs->cpu]->cur)))
 258                         {
 259                                 printk(KERN_WARNING "Warning: CPU frequency is %u, "
 260                                        "cpufreq assumed %u kHz.\n", freqs->old, cpufreq_cpu_data[freqs->cpu]->cur);
 261                                 freqs->old = cpufreq_cpu_data[freqs->cpu]->cur;
 262                         }
 263                 }
 264                 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs);
 265                 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
 266                 break;
 267         case CPUFREQ_POSTCHANGE:
 268                 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
 269                 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs);
 270                 if ((likely(cpufreq_cpu_data[freqs->cpu])) &&
 271                     (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)))
 272                         cpufreq_cpu_data[freqs->cpu]->cur = freqs->new;
 273                 break;
 274         }
 275         up_read(&cpufreq_notifier_rwsem);
 276 }
 277 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
 278
 279
 280
 281 /*********************************************************************
 282  *                          SYSFS INTERFACE                          *
 283  *********************************************************************/
 284
 285 /**
 286  * cpufreq_parse_governor - parse a governor string
 287  */
 288 int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
 289                                 struct cpufreq_governor **governor)
 290 {
 291         if (!cpufreq_driver)
 292                 return -EINVAL;
 293         if (cpufreq_driver->setpolicy) {
 294                 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
 295                         *policy = CPUFREQ_POLICY_PERFORMANCE;
 296                         return 0;
 297                 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
 298                         *policy = CPUFREQ_POLICY_POWERSAVE;
 299                         return 0;
 300                 }
 301                 return -EINVAL;
 302         } else {
 303                 struct cpufreq_governor *t;
 304                 down(&cpufreq_governor_sem);
 305                 if (!cpufreq_driver || !cpufreq_driver->target)
 306                         goto out;
 307                 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 308                         if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
 309                                 *governor = t;
 310                                 up(&cpufreq_governor_sem);
 311                                 return 0;
 312                         }
 313                 }
 314         out:
 315                 up(&cpufreq_governor_sem);
 316         }
 317         return -EINVAL;
 318 }
 319 EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
 320
 321
 322 /* drivers/base/cpu.c */
 323 extern struct sysdev_class cpu_sysdev_class;
 324
 325
 326 /**
 327  * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
 328  *
 329  * Write out information from cpufreq_driver->policy[cpu]; object must be
 330  * "unsigned int".
 331  */
 332
 333 #define show_one(file_name, object)                                     \
 334 static ssize_t show_##file_name                                         \
 335 (struct cpufreq_policy * policy, char *buf)                             \
 336 {                                                                       \
 337         return sprintf (buf, "%u\n", policy->object);                   \
 338 }
 339
 340 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 341 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 342 show_one(scaling_min_freq, min);
 343 show_one(scaling_max_freq, max);
 344 show_one(scaling_cur_freq, cur);
 345
 346 /**
 347  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
 348  */
 349 #define store_one(file_name, object)                    \
 350 static ssize_t store_##file_name                                        \
 351 (struct cpufreq_policy * policy, const char *buf, size_t count)         \
 352 {                                                                       \
 353         unsigned int ret = -EINVAL;                                     \
 354         struct cpufreq_policy new_policy;                               \
 355                                                                         \
 356         ret = cpufreq_get_policy(&new_policy, policy->cpu);             \
 357         if (ret)                                                        \
 358                 return -EINVAL;                                         \
 359                                                                         \
 360         ret = sscanf (buf, "%u", &new_policy.object);                   \
 361         if (ret != 1)                                                   \
 362                 return -EINVAL;                                         \
 363                                                                         \
 364         ret = cpufreq_set_policy(&new_policy);                          \
 365                                                                         \
 366         return ret ? ret : count;                                       \
 367 }
 368
 369 store_one(scaling_min_freq,min);
 370 store_one(scaling_max_freq,max);
 371
 372 /**
 373  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
 374  */
 375 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
 376 {
 377         unsigned int cur_freq = cpufreq_get(policy->cpu);
 378         if (!cur_freq)
 379                 return sprintf(buf, "<unknown>");
 380         return sprintf(buf, "%u\n", cur_freq);
 381 }
 382
 383
 384 /**
 385  * show_scaling_governor - show the current policy for the specified CPU
 386  */
 387 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
 388 {
 389         if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
 390                 return sprintf(buf, "powersave\n");
 391         else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 392                 return sprintf(buf, "performance\n");
 393         else if (policy->governor)
 394                 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
 395         return -EINVAL;
 396 }
 397
 398
 399 /**
 400  * store_scaling_governor - store policy for the specified CPU
 401  */
 402 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
 403                                        const char *buf, size_t count)
 404 {
 405         unsigned int ret = -EINVAL;
 406         char    str_governor[16];
 407         struct cpufreq_policy new_policy;
 408
 409         ret = cpufreq_get_policy(&new_policy, policy->cpu);
 410         if (ret)
 411                 return ret;
 412
 413         ret = sscanf (buf, "%15s", str_governor);
 414         if (ret != 1)
 415                 return -EINVAL;
 416
 417         if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
 418                 return -EINVAL;
 419
 420         ret = cpufreq_set_policy(&new_policy);
 421
 422         return ret ? ret : count;
 423 }
 424
 425 /**
 426  * show_scaling_driver - show the cpufreq driver currently loaded
 427  */
 428 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
 429 {
 430         return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
 431 }
 432
 433 /**
 434  * show_scaling_available_governors - show the available CPUfreq governors
 435  */
 436 static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
 437                                 char *buf)
 438 {
 439         ssize_t i = 0;
 440         struct cpufreq_governor *t;
 441
 442         if (!cpufreq_driver->target) {
 443                 i += sprintf(buf, "performance powersave");
 444                 goto out;
 445         }
 446
 447         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
 448                 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
 449                         goto out;
 450                 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
 451         }
 452  out:
 453         i += sprintf(&buf[i], "\n");
 454         return i;
 455 }
 456 /**
 457  * show_affected_cpus - show the CPUs affected by each transition
 458  */
 459 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
 460 {
 461         ssize_t i = 0;
 462         unsigned int cpu;
 463
 464         for_each_cpu_mask(cpu, policy->cpus) {
 465                 if (i)
 466                         i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
 467                 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
 468                 if (i >= (PAGE_SIZE - 5))
 469                     break;
 470         }
 471         i += sprintf(&buf[i], "\n");
 472         return i;
 473 }
 474
 475
 476 #define define_one_ro(_name) \
 477 static struct freq_attr _name = \
 478 __ATTR(_name, 0444, show_##_name, NULL)
 479
 480 #define define_one_ro0400(_name) \
 481 static struct freq_attr _name = \
 482 __ATTR(_name, 0400, show_##_name, NULL)
 483
 484 #define define_one_rw(_name) \
 485 static struct freq_attr _name = \
 486 __ATTR(_name, 0644, show_##_name, store_##_name)
 487
 488 define_one_ro0400(cpuinfo_cur_freq);
 489 define_one_ro(cpuinfo_min_freq);
 490 define_one_ro(cpuinfo_max_freq);
 491 define_one_ro(scaling_available_governors);
 492 define_one_ro(scaling_driver);
 493 define_one_ro(scaling_cur_freq);
 494 define_one_ro(affected_cpus);
 495 define_one_rw(scaling_min_freq);
 496 define_one_rw(scaling_max_freq);
 497 define_one_rw(scaling_governor);
 498
 499 static struct attribute * default_attrs[] = {
 500         &cpuinfo_min_freq.attr,
 501         &cpuinfo_max_freq.attr,
 502         &scaling_min_freq.attr,
 503         &scaling_max_freq.attr,
 504         &affected_cpus.attr,
 505         &scaling_governor.attr,
 506         &scaling_driver.attr,
 507         &scaling_available_governors.attr,
 508         NULL
 509 };
 510
 511 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
 512 #define to_attr(a) container_of(a,struct freq_attr,attr)
 513
 514 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
 515 {
 516         struct cpufreq_policy * policy = to_policy(kobj);
 517         struct freq_attr * fattr = to_attr(attr);
 518         ssize_t ret;
 519         policy = cpufreq_cpu_get(policy->cpu);
 520         if (!policy)
 521                 return -EINVAL;
 522         ret = fattr->show ? fattr->show(policy,buf) : 0;
 523         cpufreq_cpu_put(policy);
 524         return ret;
 525 }
 526
 527 static ssize_t store(struct kobject * kobj, struct attribute * attr,
 528                      const char * buf, size_t count)
 529 {
 530         struct cpufreq_policy * policy = to_policy(kobj);
 531         struct freq_attr * fattr = to_attr(attr);
 532         ssize_t ret;
 533         policy = cpufreq_cpu_get(policy->cpu);
 534         if (!policy)
 535                 return -EINVAL;
 536         ret = fattr->store ? fattr->store(policy,buf,count) : 0;
 537         cpufreq_cpu_put(policy);
 538         return ret;
 539 }
 540
 541 static void cpufreq_sysfs_release(struct kobject * kobj)
 542 {
 543         struct cpufreq_policy * policy = to_policy(kobj);
 544         dprintk("last reference is dropped\n");
 545         complete(&policy->kobj_unregister);
 546 }
 547
 548 static struct sysfs_ops sysfs_ops = {
 549         .show   = show,
 550         .store  = store,
 551 };
 552
 553 static struct kobj_type ktype_cpufreq = {
 554         .sysfs_ops      = &sysfs_ops,
 555         .default_attrs  = default_attrs,
 556         .release        = cpufreq_sysfs_release,
 557 };
 558
 559
 560 /**
 561  * cpufreq_add_dev - add a CPU device
 562  *
 563  * Adds the cpufreq interface for a CPU device.
 564  */
 565 static int cpufreq_add_dev (struct sys_device * sys_dev)
 566 {
 567         unsigned int cpu = sys_dev->id;
 568         int ret = 0;
 569         struct cpufreq_policy new_policy;
 570         struct cpufreq_policy *policy;
 571         struct freq_attr **drv_attr;
 572         unsigned long flags;
 573         unsigned int j;
 574
 575         cpufreq_debug_disable_ratelimit();
 576         dprintk("adding CPU %u\n", cpu);
 577
 578 #ifdef CONFIG_SMP
 579         /* check whether a different CPU already registered this
 580          * CPU because it is in the same boat. */
 581         policy = cpufreq_cpu_get(cpu);
 582         if (unlikely(policy)) {
 583                 cpu_sys_devices[cpu] = sys_dev;
 584                 dprintk("CPU already managed, adding link\n");
 585                 sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
 586                 cpufreq_debug_enable_ratelimit();
 587                 return 0;
 588         }
 589 #endif
 590
 591         if (!try_module_get(cpufreq_driver->owner)) {
 592                 ret = -EINVAL;
 593                 goto module_out;
 594         }
 595
 596         policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
 597         if (!policy) {
 598                 ret = -ENOMEM;
 599                 goto nomem_out;
 600         }
 601         memset(policy, 0, sizeof(struct cpufreq_policy));
 602
 603         policy->cpu = cpu;
 604         policy->cpus = cpumask_of_cpu(cpu);
 605
 606         init_MUTEX_LOCKED(&policy->lock);
 607         init_completion(&policy->kobj_unregister);
 608         INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
 609
 610         /* call driver. From then on the cpufreq must be able
 611          * to accept all calls to ->verify and ->setpolicy for this CPU
 612          */
 613         ret = cpufreq_driver->init(policy);
 614         if (ret) {
 615                 dprintk("initialization failed\n");
 616                 goto err_out;
 617         }
 618
 619         memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
 620
 621         /* prepare interface data */
 622         policy->kobj.parent = &sys_dev->kobj;
 623         policy->kobj.ktype = &ktype_cpufreq;
 624         strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
 625
 626         ret = kobject_register(&policy->kobj);
 627         if (ret)
 628                 goto err_out;
 629
 630         /* set up files for this cpu device */
 631         drv_attr = cpufreq_driver->attr;
 632         while ((drv_attr) && (*drv_attr)) {
 633                 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 634                 drv_attr++;
 635         }
 636         if (cpufreq_driver->get)
 637                 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
 638         if (cpufreq_driver->target)
 639                 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 640
 641         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 642         for_each_cpu_mask(j, policy->cpus)
 643                 cpufreq_cpu_data[j] = policy;
 644         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 645         policy->governor = NULL; /* to assure that the starting sequence is
 646                                   * run in cpufreq_set_policy */
 647         up(&policy->lock);
 648
 649         /* set default policy */
 650
 651         ret = cpufreq_set_policy(&new_policy);
 652         if (ret) {
 653                 dprintk("setting policy failed\n");
 654                 goto err_out_unregister;
 655         }
 656
 657         module_put(cpufreq_driver->owner);
 658         cpu_sys_devices[cpu] = sys_dev;
 659         dprintk("initialization complete\n");
 660         cpufreq_debug_enable_ratelimit();
 661
 662         return 0;
 663
 664
 665 err_out_unregister:
 666         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 667         for_each_cpu_mask(j, policy->cpus)
 668                 cpufreq_cpu_data[j] = NULL;
 669         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 670
 671         kobject_unregister(&policy->kobj);
 672         wait_for_completion(&policy->kobj_unregister);
 673
 674 err_out:
 675         kfree(policy);
 676
 677 nomem_out:
 678         module_put(cpufreq_driver->owner);
 679  module_out:
 680         cpufreq_debug_enable_ratelimit();
 681         return ret;
 682 }
 683
 684
 685 /**
 686  * cpufreq_remove_dev - remove a CPU device
 687  *
 688  * Removes the cpufreq interface for a CPU device.
 689  */
 690 static int cpufreq_remove_dev (struct sys_device * sys_dev)
 691 {
 692         unsigned int cpu = sys_dev->id;
 693         unsigned long flags;
 694         struct cpufreq_policy *data;
 695 #ifdef CONFIG_SMP
 696         unsigned int j;
 697 #endif
 698
 699         cpufreq_debug_disable_ratelimit();
 700         dprintk("unregistering CPU %u\n", cpu);
 701
 702         spin_lock_irqsave(&cpufreq_driver_lock, flags);
 703         data = cpufreq_cpu_data[cpu];
 704
 705         if (!data) {
 706                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 707                 cpu_sys_devices[cpu] = NULL;
 708                 cpufreq_debug_enable_ratelimit();
 709                 return -EINVAL;
 710         }
 711         cpufreq_cpu_data[cpu] = NULL;
 712
 713
 714 #ifdef CONFIG_SMP
 715         /* if this isn't the CPU which is the parent of the kobj, we
 716          * only need to unlink, put and exit
 717          */
 718         if (unlikely(cpu != data->cpu)) {
 719                 dprintk("removing link\n");
 720                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 721                 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
 722                 cpu_sys_devices[cpu] = NULL;
 723                 cpufreq_cpu_put(data);
 724                 cpufreq_debug_enable_ratelimit();
 725                 return 0;
 726         }
 727 #endif
 728
 729         cpu_sys_devices[cpu] = NULL;
 730
 731         if (!kobject_get(&data->kobj)) {
 732                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 733                 cpufreq_debug_enable_ratelimit();
 734                 return -EFAULT;
 735         }
 736
 737 #ifdef CONFIG_SMP
 738         /* if we have other CPUs still registered, we need to unlink them,
 739          * or else wait_for_completion below will lock up. Clean the
 740          * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
 741          * links afterwards.
 742          */
 743         if (unlikely(cpus_weight(data->cpus) > 1)) {
 744                 for_each_cpu_mask(j, data->cpus) {
 745                         if (j == cpu)
 746                                 continue;
 747                         cpufreq_cpu_data[j] = NULL;
 748                 }
 749         }
 750
 751         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 752
 753         if (unlikely(cpus_weight(data->cpus) > 1)) {
 754                 for_each_cpu_mask(j, data->cpus) {
 755                         if (j == cpu)
 756                                 continue;
 757                         dprintk("removing link for cpu %u\n", j);
 758                         sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
 759                         cpufreq_cpu_put(data);
 760                 }
 761         }
 762 #else
 763         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 764 #endif
 765
 766         if (cpufreq_driver->target)
 767                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
 768
 769         kobject_unregister(&data->kobj);
 770
 771         kobject_put(&data->kobj);
 772
 773         /* we need to make sure that the underlying kobj is actually
 774          * not referenced anymore by anybody before we proceed with
 775          * unloading.
 776          */
 777         dprintk("waiting for dropping of refcount\n");
 778         wait_for_completion(&data->kobj_unregister);
 779         dprintk("wait complete\n");
 780
 781         if (cpufreq_driver->exit)
 782                 cpufreq_driver->exit(data);
 783
 784         kfree(data);
 785
 786         cpufreq_debug_enable_ratelimit();
 787
 788         return 0;
 789 }
 790
 791
 792 static void handle_update(void *data)
 793 {
 794         unsigned int cpu = (unsigned int)(long)data;
 795         dprintk("handle_update for cpu %u called\n", cpu);
 796         cpufreq_update_policy(cpu);
 797 }
 798
 799 /**
 800  *      cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
 801  *      @cpu: cpu number
 802  *      @old_freq: CPU frequency the kernel thinks the CPU runs at
 803  *      @new_freq: CPU frequency the CPU actually runs at
 804  *
 805  *      We adjust to current frequency first, and need to clean up later. So either call
 806  *      to cpufreq_update_policy() or schedule handle_update()).
 807  */
 808 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
 809 {
 810         struct cpufreq_freqs freqs;
 811
 812         printk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
 813                "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
 814
 815         freqs.cpu = cpu;
 816         freqs.old = old_freq;
 817         freqs.new = new_freq;
 818         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 819         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 820 }
 821
 822
 823 /**
 824  * cpufreq_get - get the current CPU frequency (in kHz)
 825  * @cpu: CPU number
 826  *
 827  * Get the CPU current (static) CPU frequency
 828  */
 829 unsigned int cpufreq_get(unsigned int cpu)
 830 {
 831         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 832         unsigned int ret = 0;
 833
 834         if (!policy)
 835                 return 0;
 836
 837         if (!cpufreq_driver->get)
 838                 goto out;
 839
 840         down(&policy->lock);
 841
 842         ret = cpufreq_driver->get(cpu);
 843
 844         if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS))
 845         {
 846                 /* verify no discrepancy between actual and saved value exists */
 847                 if (unlikely(ret != policy->cur)) {
 848                         cpufreq_out_of_sync(cpu, policy->cur, ret);
 849                         schedule_work(&policy->update);
 850                 }
 851         }
 852
 853         up(&policy->lock);
 854
 855  out:
 856         cpufreq_cpu_put(policy);
 857
 858         return (ret);
 859 }
 860 EXPORT_SYMBOL(cpufreq_get);
 861
 862
 863 /**
 864  *      cpufreq_resume -  restore proper CPU frequency handling after resume
 865  *
 866  *      1.) resume CPUfreq hardware support (cpufreq_driver->resume())
 867  *      2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
 868  *      3.) schedule call cpufreq_update_policy() ASAP as interrupts are restored.
 869  */
 870 static int cpufreq_resume(struct sys_device * sysdev)
 871 {
 872         int cpu = sysdev->id;
 873         unsigned int ret = 0;
 874         struct cpufreq_policy *cpu_policy;
 875
 876         dprintk("resuming cpu %u\n", cpu);
 877
 878         if (!cpu_online(cpu))
 879                 return 0;
 880
 881         /* we may be lax here as interrupts are off. Nonetheless
 882          * we need to grab the correct cpu policy, as to check
 883          * whether we really run on this CPU.
 884          */
 885
 886         cpu_policy = cpufreq_cpu_get(cpu);
 887         if (!cpu_policy)
 888                 return -EINVAL;
 889
 890         /* only handle each CPU group once */
 891         if (unlikely(cpu_policy->cpu != cpu)) {
 892                 cpufreq_cpu_put(cpu_policy);
 893                 return 0;
 894         }
 895
 896         if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 897                 unsigned int cur_freq = 0;
 898
 899                 if (cpufreq_driver->get)
 900                         cur_freq = cpufreq_driver->get(cpu_policy->cpu);
 901
 902                 if (!cur_freq || !cpu_policy->cur) {
 903                         printk(KERN_ERR "cpufreq: resume failed to assert current frequency is what timing core thinks it is.\n");
 904                         goto out;
 905                 }
 906
 907                 if (unlikely(cur_freq != cpu_policy->cur)) {
 908                         struct cpufreq_freqs freqs;
 909
 910                         printk(KERN_WARNING "Warning: CPU frequency is %u, "
 911                                "cpufreq assumed %u kHz.\n", cur_freq, cpu_policy->cur);
 912
 913                         freqs.cpu = cpu;
 914                         freqs.old = cpu_policy->cur;
 915                         freqs.new = cur_freq;
 916
 917                         notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_RESUMECHANGE, &freqs);
 918                         adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
 919
 920                         cpu_policy->cur = cur_freq;
 921                 }
 922         }
 923
 924 out:
 925         schedule_work(&cpu_policy->update);
 926         cpufreq_cpu_put(cpu_policy);
 927         return ret;
 928 }
 929
 930 static struct sysdev_driver cpufreq_sysdev_driver = {
 931         .add            = cpufreq_add_dev,
 932         .remove         = cpufreq_remove_dev,
 933         .resume         = cpufreq_resume,
 934 };
 935
 936
 937 /*********************************************************************
 938  *                     NOTIFIER LISTS INTERFACE                      *
 939  *********************************************************************/
 940
 941 /**
 942  *      cpufreq_register_notifier - register a driver with cpufreq
 943  *      @nb: notifier function to register
 944  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
 945  *
 946  *      Add a driver to one of two lists: either a list of drivers that
 947  *      are notified about clock rate changes (once before and once after
 948  *      the transition), or a list of drivers that are notified about
 949  *      changes in cpufreq policy.
 950  *
 951  *      This function may sleep, and has the same return conditions as
 952  *      notifier_chain_register.
 953  */
 954 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
 955 {
 956         int ret;
 957
 958         down_write(&cpufreq_notifier_rwsem);
 959         switch (list) {
 960         case CPUFREQ_TRANSITION_NOTIFIER:
 961                 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
 962                 break;
 963         case CPUFREQ_POLICY_NOTIFIER:
 964                 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
 965                 break;
 966         default:
 967                 ret = -EINVAL;
 968         }
 969         up_write(&cpufreq_notifier_rwsem);
 970
 971         return ret;
 972 }
 973 EXPORT_SYMBOL(cpufreq_register_notifier);
 974
 975
 976 /**
 977  *      cpufreq_unregister_notifier - unregister a driver with cpufreq
 978  *      @nb: notifier block to be unregistered
 979  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
 980  *
 981  *      Remove a driver from the CPU frequency notifier list.
 982  *
 983  *      This function may sleep, and has the same return conditions as
 984  *      notifier_chain_unregister.
 985  */
 986 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
 987 {
 988         int ret;
 989
 990         down_write(&cpufreq_notifier_rwsem);
 991         switch (list) {
 992         case CPUFREQ_TRANSITION_NOTIFIER:
 993                 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
 994                 break;
 995         case CPUFREQ_POLICY_NOTIFIER:
 996                 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
 997                 break;
 998         default:
 999                 ret = -EINVAL;
1000         }
1001         up_write(&cpufreq_notifier_rwsem);
1002
1003         return ret;
1004 }
1005 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1006
1007
1008 /*********************************************************************
1009  *                              GOVERNORS                            *
1010  *********************************************************************/
1011
1012
1013 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1014                             unsigned int target_freq,
1015                             unsigned int relation)
1016 {
1017         int retval = -EINVAL;
1018         lock_cpu_hotplug();
1019         dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1020                 target_freq, relation);
1021         if (cpu_online(policy->cpu))
1022                 retval = cpufreq_driver->target(policy, target_freq, relation);
1023         unlock_cpu_hotplug();
1024         return retval;
1025 }
1026 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1027
1028
1029 int cpufreq_driver_target(struct cpufreq_policy *policy,
1030                           unsigned int target_freq,
1031                           unsigned int relation)
1032 {
1033         unsigned int ret;
1034
1035         policy = cpufreq_cpu_get(policy->cpu);
1036         if (!policy)
1037                 return -EINVAL;
1038
1039         down(&policy->lock);
1040
1041         ret = __cpufreq_driver_target(policy, target_freq, relation);
1042
1043         up(&policy->lock);
1044
1045         cpufreq_cpu_put(policy);
1046
1047         return ret;
1048 }
1049 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1050
1051
1052 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1053 {
1054         int ret = -EINVAL;
1055
1056         if (!try_module_get(policy->governor->owner))
1057                 return -EINVAL;
1058
1059         dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1060         ret = policy->governor->governor(policy, event);
1061
1062         /* we keep one module reference alive for each CPU governed by this CPU */
1063         if ((event != CPUFREQ_GOV_START) || ret)
1064                 module_put(policy->governor->owner);
1065         if ((event == CPUFREQ_GOV_STOP) && !ret)
1066                 module_put(policy->governor->owner);
1067
1068         return ret;
1069 }
1070
1071
1072 int cpufreq_governor(unsigned int cpu, unsigned int event)
1073 {
1074         int ret = 0;
1075         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1076
1077         if (!policy)
1078                 return -EINVAL;
1079
1080         down(&policy->lock);
1081         ret = __cpufreq_governor(policy, event);
1082         up(&policy->lock);
1083
1084         cpufreq_cpu_put(policy);
1085
1086         return ret;
1087 }
1088 EXPORT_SYMBOL_GPL(cpufreq_governor);
1089
1090
1091 int cpufreq_register_governor(struct cpufreq_governor *governor)
1092 {
1093         struct cpufreq_governor *t;
1094
1095         if (!governor)
1096                 return -EINVAL;
1097
1098         down(&cpufreq_governor_sem);
1099
1100         list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1101                 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1102                         up(&cpufreq_governor_sem);
1103                         return -EBUSY;
1104                 }
1105         }
1106         list_add(&governor->governor_list, &cpufreq_governor_list);
1107
1108         up(&cpufreq_governor_sem);
1109
1110         return 0;
1111 }
1112 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1113
1114
1115 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1116 {
1117         if (!governor)
1118                 return;
1119
1120         down(&cpufreq_governor_sem);
1121         list_del(&governor->governor_list);
1122         up(&cpufreq_governor_sem);
1123         return;
1124 }
1125 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1126
1127
1128
1129 /*********************************************************************
1130  *                          POLICY INTERFACE                         *
1131  *********************************************************************/
1132
1133 /**
1134  * cpufreq_get_policy - get the current cpufreq_policy
1135  * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1136  *
1137  * Reads the current cpufreq policy.
1138  */
1139 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1140 {
1141         struct cpufreq_policy *cpu_policy;
1142         if (!policy)
1143                 return -EINVAL;
1144
1145         cpu_policy = cpufreq_cpu_get(cpu);
1146         if (!cpu_policy)
1147                 return -EINVAL;
1148
1149         down(&cpu_policy->lock);
1150         memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1151         up(&cpu_policy->lock);
1152
1153         cpufreq_cpu_put(cpu_policy);
1154
1155         return 0;
1156 }
1157 EXPORT_SYMBOL(cpufreq_get_policy);
1158
1159
1160 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1161 {
1162         int ret = 0;
1163
1164         cpufreq_debug_disable_ratelimit();
1165         dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1166                 policy->min, policy->max);
1167
1168         memcpy(&policy->cpuinfo,
1169                &data->cpuinfo,
1170                sizeof(struct cpufreq_cpuinfo));
1171
1172         /* verify the cpu speed can be set within this limit */
1173         ret = cpufreq_driver->verify(policy);
1174         if (ret)
1175                 goto error_out;
1176
1177         down_read(&cpufreq_notifier_rwsem);
1178
1179         /* adjust if necessary - all reasons */
1180         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1181                             policy);
1182
1183         /* adjust if necessary - hardware incompatibility*/
1184         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1185                             policy);
1186
1187         /* verify the cpu speed can be set within this limit,
1188            which might be different to the first one */
1189         ret = cpufreq_driver->verify(policy);
1190         if (ret) {
1191                 up_read(&cpufreq_notifier_rwsem);
1192                 goto error_out;
1193         }
1194
1195         /* notification of the new policy */
1196         notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1197                             policy);
1198
1199         up_read(&cpufreq_notifier_rwsem);
1200
1201         data->min    = policy->min;
1202         data->max    = policy->max;
1203
1204         dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1205
1206         if (cpufreq_driver->setpolicy) {
1207                 data->policy = policy->policy;
1208                 dprintk("setting range\n");
1209                 ret = cpufreq_driver->setpolicy(policy);
1210         } else {
1211                 if (policy->governor != data->governor) {
1212                         /* save old, working values */
1213                         struct cpufreq_governor *old_gov = data->governor;
1214
1215                         dprintk("governor switch\n");
1216
1217                         /* end old governor */
1218                         if (data->governor)
1219                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1220
1221                         /* start new governor */
1222                         data->governor = policy->governor;
1223                         if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1224                                 /* new governor failed, so re-start old one */
1225                                 dprintk("starting governor %s failed\n", data->governor->name);
1226                                 if (old_gov) {
1227                                         data->governor = old_gov;
1228                                         __cpufreq_governor(data, CPUFREQ_GOV_START);
1229                                 }
1230                                 ret = -EINVAL;
1231                                 goto error_out;
1232                         }
1233                         /* might be a policy change, too, so fall through */
1234                 }
1235                 dprintk("governor: change or update limits\n");
1236                 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1237         }
1238
1239  error_out:
1240         cpufreq_debug_enable_ratelimit();
1241         return ret;
1242 }
1243
1244 /**
1245  *      cpufreq_set_policy - set a new CPUFreq policy
1246  *      @policy: policy to be set.
1247  *
1248  *      Sets a new CPU frequency and voltage scaling policy.
1249  */
1250 int cpufreq_set_policy(struct cpufreq_policy *policy)
1251 {
1252         int ret = 0;
1253         struct cpufreq_policy *data;
1254
1255         if (!policy)
1256                 return -EINVAL;
1257
1258         data = cpufreq_cpu_get(policy->cpu);
1259         if (!data)
1260                 return -EINVAL;
1261
1262         /* lock this CPU */
1263         down(&data->lock);
1264
1265         ret = __cpufreq_set_policy(data, policy);
1266         data->user_policy.min = data->min;
1267         data->user_policy.max = data->max;
1268         data->user_policy.policy = data->policy;
1269         data->user_policy.governor = data->governor;
1270
1271         up(&data->lock);
1272         cpufreq_cpu_put(data);
1273
1274         return ret;
1275 }
1276 EXPORT_SYMBOL(cpufreq_set_policy);
1277
1278
1279 /**
1280  *      cpufreq_update_policy - re-evaluate an existing cpufreq policy
1281  *      @cpu: CPU which shall be re-evaluated
1282  *
1283  *      Usefull for policy notifiers which have different necessities
1284  *      at different times.
1285  */
1286 int cpufreq_update_policy(unsigned int cpu)
1287 {
1288         struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1289         struct cpufreq_policy policy;
1290         int ret = 0;
1291
1292         if (!data)
1293                 return -ENODEV;
1294
1295         down(&data->lock);
1296
1297         dprintk("updating policy for CPU %u\n", cpu);
1298         memcpy(&policy,
1299                data,
1300                sizeof(struct cpufreq_policy));
1301         policy.min = data->user_policy.min;
1302         policy.max = data->user_policy.max;
1303         policy.policy = data->user_policy.policy;
1304         policy.governor = data->user_policy.governor;
1305
1306         ret = __cpufreq_set_policy(data, &policy);
1307
1308         up(&data->lock);
1309
1310         cpufreq_cpu_put(data);
1311         return ret;
1312 }
1313 EXPORT_SYMBOL(cpufreq_update_policy);
1314
1315
1316 /*********************************************************************
1317  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
1318  *********************************************************************/
1319
1320 /**
1321  * cpufreq_register_driver - register a CPU Frequency driver
1322  * @driver_data: A struct cpufreq_driver containing the values#
1323  * submitted by the CPU Frequency driver.
1324  *
1325  *   Registers a CPU Frequency driver to this core code. This code
1326  * returns zero on success, -EBUSY when another driver got here first
1327  * (and isn't unregistered in the meantime).
1328  *
1329  */
1330 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1331 {
1332         unsigned long flags;
1333         int ret;
1334
1335         if (!driver_data || !driver_data->verify || !driver_data->init ||
1336             ((!driver_data->setpolicy) && (!driver_data->target)))
1337                 return -EINVAL;
1338
1339         dprintk("trying to register driver %s\n", driver_data->name);
1340
1341         if (driver_data->setpolicy)
1342                 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1343
1344         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1345         if (cpufreq_driver) {
1346                 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1347                 return -EBUSY;
1348         }
1349         cpufreq_driver = driver_data;
1350         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1351
1352         ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1353
1354         if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1355                 int i;
1356                 ret = -ENODEV;
1357
1358                 /* check for at least one working CPU */
1359                 for (i=0; i<NR_CPUS; i++)
1360                         if (cpufreq_cpu_data[i])
1361                                 ret = 0;
1362
1363                 /* if all ->init() calls failed, unregister */
1364                 if (ret) {
1365                         dprintk("no CPU initialized for driver %s\n", driver_data->name);
1366                         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1367
1368                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1369                         cpufreq_driver = NULL;
1370                         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1371                 }
1372         }
1373
1374         if (!ret) {
1375                 dprintk("driver %s up and running\n", driver_data->name);
1376                 cpufreq_debug_enable_ratelimit();
1377         }
1378
1379         return (ret);
1380 }
1381 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1382
1383
1384 /**
1385  * cpufreq_unregister_driver - unregister the current CPUFreq driver
1386  *
1387  *    Unregister the current CPUFreq driver. Only call this if you have
1388  * the right to do so, i.e. if you have succeeded in initialising before!
1389  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1390  * currently not initialised.
1391  */
1392 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1393 {
1394         unsigned long flags;
1395
1396         cpufreq_debug_disable_ratelimit();
1397
1398         if (!cpufreq_driver || (driver != cpufreq_driver)) {
1399                 cpufreq_debug_enable_ratelimit();
1400                 return -EINVAL;
1401         }
1402
1403         dprintk("unregistering driver %s\n", driver->name);
1404
1405         sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1406
1407         spin_lock_irqsave(&cpufreq_driver_lock, flags);
1408         cpufreq_driver = NULL;
1409         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1410
1411         return 0;
1412 }
1413 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);