include/linux/cpufreq.h

   1 /*
   2  * linux/include/linux/cpufreq.h
   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 #ifndef _LINUX_CPUFREQ_H
  12 #define _LINUX_CPUFREQ_H
  13
  14 #include <linux/cpumask.h>
  15 #include <linux/completion.h>
  16 #include <linux/kobject.h>
  17 #include <linux/notifier.h>
  18 #include <linux/sysfs.h>
  19
  20 /*********************************************************************
  21  *                        CPUFREQ INTERFACE                          *
  22  *********************************************************************/
  23 /*
  24  * Frequency values here are CPU kHz
  25  *
  26  * Maximum transition latency is in nanoseconds - if it's unknown,
  27  * CPUFREQ_ETERNAL shall be used.
  28  */
  29
  30 #define CPUFREQ_ETERNAL                 (-1)
  31 #define CPUFREQ_NAME_LEN                16
  32 /* Print length for names. Extra 1 space for accomodating '\n' in prints */
  33 #define CPUFREQ_NAME_PLEN               (CPUFREQ_NAME_LEN + 1)
  34
  35 struct cpufreq_governor;
  36
  37 struct cpufreq_freqs {
  38         unsigned int cpu;       /* cpu nr */
  39         unsigned int old;
  40         unsigned int new;
  41         u8 flags;               /* flags of cpufreq_driver, see below. */
  42 };
  43
  44 struct cpufreq_cpuinfo {
  45         unsigned int            max_freq;
  46         unsigned int            min_freq;
  47
  48         /* in 10^(-9) s = nanoseconds */
  49         unsigned int            transition_latency;
  50 };
  51
  52 struct cpufreq_real_policy {
  53         unsigned int            min;    /* in kHz */
  54         unsigned int            max;    /* in kHz */
  55         unsigned int            policy; /* see above */
  56         struct cpufreq_governor *governor; /* see below */
  57 };
  58
  59 struct cpufreq_policy {
  60         /* CPUs sharing clock, require sw coordination */
  61         cpumask_var_t           cpus;   /* Online CPUs only */
  62         cpumask_var_t           related_cpus; /* Online + Offline CPUs */
  63
  64         unsigned int            shared_type; /* ACPI: ANY or ALL affected CPUs
  65                                                 should set cpufreq */
  66         unsigned int            cpu;    /* cpu nr of CPU managing this policy */
  67         unsigned int            last_cpu; /* cpu nr of previous CPU that managed
  68                                            * this policy */
  69         struct cpufreq_cpuinfo  cpuinfo;/* see above */
  70
  71         unsigned int            min;    /* in kHz */
  72         unsigned int            max;    /* in kHz */
  73         unsigned int            cur;    /* in kHz, only needed if cpufreq
  74                                          * governors are used */
  75         unsigned int            policy; /* see above */
  76         struct cpufreq_governor *governor; /* see below */
  77         void                    *governor_data;
  78         bool                    governor_enabled; /* governor start/stop flag */
  79
  80         struct work_struct      update; /* if update_policy() needs to be
  81                                          * called, but you're in IRQ context */
  82
  83         struct cpufreq_real_policy      user_policy;
  84
  85         struct list_head        policy_list;
  86         struct kobject          kobj;
  87         struct completion       kobj_unregister;
  88
  89         /*
  90          * The rules for this semaphore:
  91          * - Any routine that wants to read from the policy structure will
  92          *   do a down_read on this semaphore.
  93          * - Any routine that will write to the policy structure and/or may take away
  94          *   the policy altogether (eg. CPU hotplug), will hold this lock in write
  95          *   mode before doing so.
  96          *
  97          * Additional rules:
  98          * - Lock should not be held across
  99          *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
 100          */
 101         struct rw_semaphore     rwsem;
 102 };
 103
 104 /* Only for ACPI */
 105 #define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
 106 #define CPUFREQ_SHARED_TYPE_HW   (1) /* HW does needed coordination */
 107 #define CPUFREQ_SHARED_TYPE_ALL  (2) /* All dependent CPUs should set freq */
 108 #define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent CPU*/
 109
 110 #ifdef CONFIG_CPU_FREQ
 111 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
 112 void cpufreq_cpu_put(struct cpufreq_policy *policy);
 113 #else
 114 static inline struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 115 {
 116         return NULL;
 117 }
 118 static inline void cpufreq_cpu_put(struct cpufreq_policy *policy) { }
 119 #endif
 120
 121 static inline bool policy_is_shared(struct cpufreq_policy *policy)
 122 {
 123         return cpumask_weight(policy->cpus) > 1;
 124 }
 125
 126 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 127 extern struct kobject *cpufreq_global_kobject;
 128 int cpufreq_get_global_kobject(void);
 129 void cpufreq_put_global_kobject(void);
 130 int cpufreq_sysfs_create_file(const struct attribute *attr);
 131 void cpufreq_sysfs_remove_file(const struct attribute *attr);
 132
 133 #ifdef CONFIG_CPU_FREQ
 134 unsigned int cpufreq_get(unsigned int cpu);
 135 unsigned int cpufreq_quick_get(unsigned int cpu);
 136 unsigned int cpufreq_quick_get_max(unsigned int cpu);
 137 void disable_cpufreq(void);
 138
 139 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 140 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 141 int cpufreq_update_policy(unsigned int cpu);
 142 bool have_governor_per_policy(void);
 143 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
 144 #else
 145 static inline unsigned int cpufreq_get(unsigned int cpu)
 146 {
 147         return 0;
 148 }
 149 static inline unsigned int cpufreq_quick_get(unsigned int cpu)
 150 {
 151         return 0;
 152 }
 153 static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
 154 {
 155         return 0;
 156 }
 157 static inline void disable_cpufreq(void) { }
 158 #endif
 159
 160 /*********************************************************************
 161  *                      CPUFREQ DRIVER INTERFACE                     *
 162  *********************************************************************/
 163
 164 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 165 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 166
 167 struct freq_attr {
 168         struct attribute attr;
 169         ssize_t (*show)(struct cpufreq_policy *, char *);
 170         ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 171 };
 172
 173 #define cpufreq_freq_attr_ro(_name)             \
 174 static struct freq_attr _name =                 \
 175 __ATTR(_name, 0444, show_##_name, NULL)
 176
 177 #define cpufreq_freq_attr_ro_perm(_name, _perm) \
 178 static struct freq_attr _name =                 \
 179 __ATTR(_name, _perm, show_##_name, NULL)
 180
 181 #define cpufreq_freq_attr_rw(_name)             \
 182 static struct freq_attr _name =                 \
 183 __ATTR(_name, 0644, show_##_name, store_##_name)
 184
 185 struct global_attr {
 186         struct attribute attr;
 187         ssize_t (*show)(struct kobject *kobj,
 188                         struct attribute *attr, char *buf);
 189         ssize_t (*store)(struct kobject *a, struct attribute *b,
 190                          const char *c, size_t count);
 191 };
 192
 193 #define define_one_global_ro(_name)             \
 194 static struct global_attr _name =               \
 195 __ATTR(_name, 0444, show_##_name, NULL)
 196
 197 #define define_one_global_rw(_name)             \
 198 static struct global_attr _name =               \
 199 __ATTR(_name, 0644, show_##_name, store_##_name)
 200
 201
 202 struct cpufreq_driver {
 203         char                    name[CPUFREQ_NAME_LEN];
 204         u8                      flags;
 205
 206         /* needed by all drivers */
 207         int     (*init)         (struct cpufreq_policy *policy);
 208         int     (*verify)       (struct cpufreq_policy *policy);
 209
 210         /* define one out of two */
 211         int     (*setpolicy)    (struct cpufreq_policy *policy);
 212         int     (*target)       (struct cpufreq_policy *policy, /* Deprecated */
 213                                  unsigned int target_freq,
 214                                  unsigned int relation);
 215         int     (*target_index) (struct cpufreq_policy *policy,
 216                                  unsigned int index);
 217
 218         /* should be defined, if possible */
 219         unsigned int    (*get)  (unsigned int cpu);
 220
 221         /* optional */
 222         int     (*bios_limit)   (int cpu, unsigned int *limit);
 223
 224         int     (*exit)         (struct cpufreq_policy *policy);
 225         int     (*suspend)      (struct cpufreq_policy *policy);
 226         int     (*resume)       (struct cpufreq_policy *policy);
 227         struct freq_attr        **attr;
 228 };
 229
 230 /* flags */
 231 #define CPUFREQ_STICKY          (1 << 0)        /* driver isn't removed even if
 232                                                    all ->init() calls failed */
 233 #define CPUFREQ_CONST_LOOPS     (1 << 1)        /* loops_per_jiffy or other
 234                                                    kernel "constants" aren't
 235                                                    affected by frequency
 236                                                    transitions */
 237 #define CPUFREQ_PM_NO_WARN      (1 << 2)        /* don't warn on suspend/resume
 238                                                    speed mismatches */
 239
 240 /*
 241  * This should be set by platforms having multiple clock-domains, i.e.
 242  * supporting multiple policies. With this sysfs directories of governor would
 243  * be created in cpu/cpu<num>/cpufreq/ directory and so they can use the same
 244  * governor with different tunables for different clusters.
 245  */
 246 #define CPUFREQ_HAVE_GOVERNOR_PER_POLICY (1 << 3)
 247
 248 /*
 249  * Driver will do POSTCHANGE notifications from outside of their ->target()
 250  * routine and so must set cpufreq_driver->flags with this flag, so that core
 251  * can handle them specially.
 252  */
 253 #define CPUFREQ_ASYNC_NOTIFICATION  (1 << 4)
 254
 255 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 256 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 257
 258 const char *cpufreq_get_current_driver(void);
 259
 260 static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy,
 261                 unsigned int min, unsigned int max)
 262 {
 263         if (policy->min < min)
 264                 policy->min = min;
 265         if (policy->max < min)
 266                 policy->max = min;
 267         if (policy->min > max)
 268                 policy->min = max;
 269         if (policy->max > max)
 270                 policy->max = max;
 271         if (policy->min > policy->max)
 272                 policy->min = policy->max;
 273         return;
 274 }
 275
 276 static inline void
 277 cpufreq_verify_within_cpu_limits(struct cpufreq_policy *policy)
 278 {
 279         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 280                         policy->cpuinfo.max_freq);
 281 }
 282
 283 /*********************************************************************
 284  *                     CPUFREQ NOTIFIER INTERFACE                    *
 285  *********************************************************************/
 286
 287 #define CPUFREQ_TRANSITION_NOTIFIER     (0)
 288 #define CPUFREQ_POLICY_NOTIFIER         (1)
 289
 290 /* Transition notifiers */
 291 #define CPUFREQ_PRECHANGE               (0)
 292 #define CPUFREQ_POSTCHANGE              (1)
 293 #define CPUFREQ_RESUMECHANGE            (8)
 294 #define CPUFREQ_SUSPENDCHANGE           (9)
 295
 296 /* Policy Notifiers  */
 297 #define CPUFREQ_ADJUST                  (0)
 298 #define CPUFREQ_INCOMPATIBLE            (1)
 299 #define CPUFREQ_NOTIFY                  (2)
 300 #define CPUFREQ_START                   (3)
 301 #define CPUFREQ_UPDATE_POLICY_CPU       (4)
 302
 303 #ifdef CONFIG_CPU_FREQ
 304 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
 305 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
 306
 307 void cpufreq_notify_transition(struct cpufreq_policy *policy,
 308                 struct cpufreq_freqs *freqs, unsigned int state);
 309
 310 #else /* CONFIG_CPU_FREQ */
 311 static inline int cpufreq_register_notifier(struct notifier_block *nb,
 312                                                 unsigned int list)
 313 {
 314         return 0;
 315 }
 316 static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
 317                                                 unsigned int list)
 318 {
 319         return 0;
 320 }
 321 #endif /* !CONFIG_CPU_FREQ */
 322
 323 /**
 324  * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch
 325  * safe)
 326  * @old:   old value
 327  * @div:   divisor
 328  * @mult:  multiplier
 329  *
 330  *
 331  * new = old * mult / div
 332  */
 333 static inline unsigned long cpufreq_scale(unsigned long old, u_int div,
 334                 u_int mult)
 335 {
 336 #if BITS_PER_LONG == 32
 337         u64 result = ((u64) old) * ((u64) mult);
 338         do_div(result, div);
 339         return (unsigned long) result;
 340
 341 #elif BITS_PER_LONG == 64
 342         unsigned long result = old * ((u64) mult);
 343         result /= div;
 344         return result;
 345 #endif
 346 }
 347
 348 /*********************************************************************
 349  *                          CPUFREQ GOVERNORS                        *
 350  *********************************************************************/
 351
 352 /*
 353  * If (cpufreq_driver->target) exists, the ->governor decides what frequency
 354  * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
 355  * two generic policies are available:
 356  */
 357 #define CPUFREQ_POLICY_POWERSAVE        (1)
 358 #define CPUFREQ_POLICY_PERFORMANCE      (2)
 359
 360 /* Governor Events */
 361 #define CPUFREQ_GOV_START       1
 362 #define CPUFREQ_GOV_STOP        2
 363 #define CPUFREQ_GOV_LIMITS      3
 364 #define CPUFREQ_GOV_POLICY_INIT 4
 365 #define CPUFREQ_GOV_POLICY_EXIT 5
 366
 367 struct cpufreq_governor {
 368         char    name[CPUFREQ_NAME_LEN];
 369         int     initialized;
 370         int     (*governor)     (struct cpufreq_policy *policy,
 371                                  unsigned int event);
 372         ssize_t (*show_setspeed)        (struct cpufreq_policy *policy,
 373                                          char *buf);
 374         int     (*store_setspeed)       (struct cpufreq_policy *policy,
 375                                          unsigned int freq);
 376         unsigned int max_transition_latency; /* HW must be able to switch to
 377                         next freq faster than this value in nano secs or we
 378                         will fallback to performance governor */
 379         struct list_head        governor_list;
 380         struct module           *owner;
 381 };
 382
 383 /* Pass a target to the cpufreq driver */
 384 int cpufreq_driver_target(struct cpufreq_policy *policy,
 385                                  unsigned int target_freq,
 386                                  unsigned int relation);
 387 int __cpufreq_driver_target(struct cpufreq_policy *policy,
 388                                    unsigned int target_freq,
 389                                    unsigned int relation);
 390 int cpufreq_register_governor(struct cpufreq_governor *governor);
 391 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 392
 393 /* CPUFREQ DEFAULT GOVERNOR */
 394 /*
 395  * Performance governor is fallback governor if any other gov failed to auto
 396  * load due latency restrictions
 397  */
 398 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
 399 extern struct cpufreq_governor cpufreq_gov_performance;
 400 #endif
 401 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 402 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_performance)
 403 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
 404 extern struct cpufreq_governor cpufreq_gov_powersave;
 405 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_powersave)
 406 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 407 extern struct cpufreq_governor cpufreq_gov_userspace;
 408 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_userspace)
 409 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
 410 extern struct cpufreq_governor cpufreq_gov_ondemand;
 411 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_ondemand)
 412 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
 413 extern struct cpufreq_governor cpufreq_gov_conservative;
 414 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_conservative)
 415 #endif
 416
 417 /*********************************************************************
 418  *                     FREQUENCY TABLE HELPERS                       *
 419  *********************************************************************/
 420
 421 #define CPUFREQ_ENTRY_INVALID ~0
 422 #define CPUFREQ_TABLE_END     ~1
 423
 424 struct cpufreq_frequency_table {
 425         unsigned int    driver_data; /* driver specific data, not used by core */
 426         unsigned int    frequency; /* kHz - doesn't need to be in ascending
 427                                     * order */
 428 };
 429
 430 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 431                                     struct cpufreq_frequency_table *table);
 432
 433 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 434                                    struct cpufreq_frequency_table *table);
 435 int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy);
 436
 437 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 438                                    struct cpufreq_frequency_table *table,
 439                                    unsigned int target_freq,
 440                                    unsigned int relation,
 441                                    unsigned int *index);
 442
 443 void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
 444 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
 445
 446 /* the following funtion is for cpufreq core use only */
 447 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 448
 449 /* the following are really really optional */
 450 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 451 extern struct freq_attr *cpufreq_generic_attr[];
 452 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 453                                       unsigned int cpu);
 454 void cpufreq_frequency_table_put_attr(unsigned int cpu);
 455 int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
 456                                       struct cpufreq_frequency_table *table);
 457
 458 int cpufreq_generic_init(struct cpufreq_policy *policy,
 459                 struct cpufreq_frequency_table *table,
 460                 unsigned int transition_latency);
 461 static inline int cpufreq_generic_exit(struct cpufreq_policy *policy)
 462 {
 463         cpufreq_frequency_table_put_attr(policy->cpu);
 464         return 0;
 465 }
 466
 467 #endif /* _LINUX_CPUFREQ_H */