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         int                     transition_ongoing; /* Tracks transition status */
  89 };
  90
  91 /* Only for ACPI */
  92 #define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
  93 #define CPUFREQ_SHARED_TYPE_HW   (1) /* HW does needed coordination */
  94 #define CPUFREQ_SHARED_TYPE_ALL  (2) /* All dependent CPUs should set freq */
  95 #define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent CPU*/
  96
  97 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
  98 void cpufreq_cpu_put(struct cpufreq_policy *policy);
  99
 100 static inline bool policy_is_shared(struct cpufreq_policy *policy)
 101 {
 102         return cpumask_weight(policy->cpus) > 1;
 103 }
 104
 105 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 106 extern struct kobject *cpufreq_global_kobject;
 107 int cpufreq_get_global_kobject(void);
 108 void cpufreq_put_global_kobject(void);
 109 int cpufreq_sysfs_create_file(const struct attribute *attr);
 110 void cpufreq_sysfs_remove_file(const struct attribute *attr);
 111
 112 #ifdef CONFIG_CPU_FREQ
 113 unsigned int cpufreq_get(unsigned int cpu);
 114 unsigned int cpufreq_quick_get(unsigned int cpu);
 115 unsigned int cpufreq_quick_get_max(unsigned int cpu);
 116 void disable_cpufreq(void);
 117
 118 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 119 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 120 int cpufreq_update_policy(unsigned int cpu);
 121 bool have_governor_per_policy(void);
 122 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
 123 #else
 124 static inline unsigned int cpufreq_get(unsigned int cpu)
 125 {
 126         return 0;
 127 }
 128 static inline unsigned int cpufreq_quick_get(unsigned int cpu)
 129 {
 130         return 0;
 131 }
 132 static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
 133 {
 134         return 0;
 135 }
 136 static inline void disable_cpufreq(void) { }
 137 #endif
 138
 139 /*********************************************************************
 140  *                      CPUFREQ DRIVER INTERFACE                     *
 141  *********************************************************************/
 142
 143 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 144 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 145
 146 struct freq_attr {
 147         struct attribute attr;
 148         ssize_t (*show)(struct cpufreq_policy *, char *);
 149         ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 150 };
 151
 152 #define cpufreq_freq_attr_ro(_name)             \
 153 static struct freq_attr _name =                 \
 154 __ATTR(_name, 0444, show_##_name, NULL)
 155
 156 #define cpufreq_freq_attr_ro_perm(_name, _perm) \
 157 static struct freq_attr _name =                 \
 158 __ATTR(_name, _perm, show_##_name, NULL)
 159
 160 #define cpufreq_freq_attr_rw(_name)             \
 161 static struct freq_attr _name =                 \
 162 __ATTR(_name, 0644, show_##_name, store_##_name)
 163
 164 struct global_attr {
 165         struct attribute attr;
 166         ssize_t (*show)(struct kobject *kobj,
 167                         struct attribute *attr, char *buf);
 168         ssize_t (*store)(struct kobject *a, struct attribute *b,
 169                          const char *c, size_t count);
 170 };
 171
 172 #define define_one_global_ro(_name)             \
 173 static struct global_attr _name =               \
 174 __ATTR(_name, 0444, show_##_name, NULL)
 175
 176 #define define_one_global_rw(_name)             \
 177 static struct global_attr _name =               \
 178 __ATTR(_name, 0644, show_##_name, store_##_name)
 179
 180
 181 struct cpufreq_driver {
 182         struct module           *owner;
 183         char                    name[CPUFREQ_NAME_LEN];
 184         u8                      flags;
 185         /*
 186          * This should be set by platforms having multiple clock-domains, i.e.
 187          * supporting multiple policies. With this sysfs directories of governor
 188          * would be created in cpu/cpu<num>/cpufreq/ directory and so they can
 189          * use the same governor with different tunables for different clusters.
 190          */
 191         bool                    have_governor_per_policy;
 192
 193         /* needed by all drivers */
 194         int     (*init)         (struct cpufreq_policy *policy);
 195         int     (*verify)       (struct cpufreq_policy *policy);
 196
 197         /* define one out of two */
 198         int     (*setpolicy)    (struct cpufreq_policy *policy);
 199         int     (*target)       (struct cpufreq_policy *policy,
 200                                  unsigned int target_freq,
 201                                  unsigned int relation);
 202
 203         /* should be defined, if possible */
 204         unsigned int    (*get)  (unsigned int cpu);
 205
 206         /* optional */
 207         int     (*bios_limit)   (int cpu, unsigned int *limit);
 208
 209         int     (*exit)         (struct cpufreq_policy *policy);
 210         int     (*suspend)      (struct cpufreq_policy *policy);
 211         int     (*resume)       (struct cpufreq_policy *policy);
 212         struct freq_attr        **attr;
 213 };
 214
 215 /* flags */
 216 #define CPUFREQ_STICKY          0x01    /* the driver isn't removed even if
 217                                          * all ->init() calls failed */
 218 #define CPUFREQ_CONST_LOOPS     0x02    /* loops_per_jiffy or other kernel
 219                                          * "constants" aren't affected by
 220                                          * frequency transitions */
 221 #define CPUFREQ_PM_NO_WARN      0x04    /* don't warn on suspend/resume speed
 222                                          * mismatches */
 223
 224 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 225 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 226
 227 const char *cpufreq_get_current_driver(void);
 228
 229 static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy,
 230                 unsigned int min, unsigned int max)
 231 {
 232         if (policy->min < min)
 233                 policy->min = min;
 234         if (policy->max < min)
 235                 policy->max = min;
 236         if (policy->min > max)
 237                 policy->min = max;
 238         if (policy->max > max)
 239                 policy->max = max;
 240         if (policy->min > policy->max)
 241                 policy->min = policy->max;
 242         return;
 243 }
 244
 245 /*********************************************************************
 246  *                     CPUFREQ NOTIFIER INTERFACE                    *
 247  *********************************************************************/
 248
 249 #define CPUFREQ_TRANSITION_NOTIFIER     (0)
 250 #define CPUFREQ_POLICY_NOTIFIER         (1)
 251
 252 /* Transition notifiers */
 253 #define CPUFREQ_PRECHANGE               (0)
 254 #define CPUFREQ_POSTCHANGE              (1)
 255 #define CPUFREQ_RESUMECHANGE            (8)
 256 #define CPUFREQ_SUSPENDCHANGE           (9)
 257
 258 /* Policy Notifiers  */
 259 #define CPUFREQ_ADJUST                  (0)
 260 #define CPUFREQ_INCOMPATIBLE            (1)
 261 #define CPUFREQ_NOTIFY                  (2)
 262 #define CPUFREQ_START                   (3)
 263 #define CPUFREQ_UPDATE_POLICY_CPU       (4)
 264
 265 #ifdef CONFIG_CPU_FREQ
 266 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
 267 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
 268
 269 void cpufreq_notify_transition(struct cpufreq_policy *policy,
 270                 struct cpufreq_freqs *freqs, unsigned int state);
 271
 272 #else /* CONFIG_CPU_FREQ */
 273 static inline int cpufreq_register_notifier(struct notifier_block *nb,
 274                                                 unsigned int list)
 275 {
 276         return 0;
 277 }
 278 static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
 279                                                 unsigned int list)
 280 {
 281         return 0;
 282 }
 283 #endif /* !CONFIG_CPU_FREQ */
 284
 285 /**
 286  * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch
 287  * safe)
 288  * @old:   old value
 289  * @div:   divisor
 290  * @mult:  multiplier
 291  *
 292  *
 293  * new = old * mult / div
 294  */
 295 static inline unsigned long cpufreq_scale(unsigned long old, u_int div,
 296                 u_int mult)
 297 {
 298 #if BITS_PER_LONG == 32
 299         u64 result = ((u64) old) * ((u64) mult);
 300         do_div(result, div);
 301         return (unsigned long) result;
 302
 303 #elif BITS_PER_LONG == 64
 304         unsigned long result = old * ((u64) mult);
 305         result /= div;
 306         return result;
 307 #endif
 308 }
 309
 310 /*********************************************************************
 311  *                          CPUFREQ GOVERNORS                        *
 312  *********************************************************************/
 313
 314 /*
 315  * If (cpufreq_driver->target) exists, the ->governor decides what frequency
 316  * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
 317  * two generic policies are available:
 318  */
 319 #define CPUFREQ_POLICY_POWERSAVE        (1)
 320 #define CPUFREQ_POLICY_PERFORMANCE      (2)
 321
 322 /* Governor Events */
 323 #define CPUFREQ_GOV_START       1
 324 #define CPUFREQ_GOV_STOP        2
 325 #define CPUFREQ_GOV_LIMITS      3
 326 #define CPUFREQ_GOV_POLICY_INIT 4
 327 #define CPUFREQ_GOV_POLICY_EXIT 5
 328
 329 struct cpufreq_governor {
 330         char    name[CPUFREQ_NAME_LEN];
 331         int     initialized;
 332         int     (*governor)     (struct cpufreq_policy *policy,
 333                                  unsigned int event);
 334         ssize_t (*show_setspeed)        (struct cpufreq_policy *policy,
 335                                          char *buf);
 336         int     (*store_setspeed)       (struct cpufreq_policy *policy,
 337                                          unsigned int freq);
 338         unsigned int max_transition_latency; /* HW must be able to switch to
 339                         next freq faster than this value in nano secs or we
 340                         will fallback to performance governor */
 341         struct list_head        governor_list;
 342         struct module           *owner;
 343 };
 344
 345 /* Pass a target to the cpufreq driver */
 346 int cpufreq_driver_target(struct cpufreq_policy *policy,
 347                                  unsigned int target_freq,
 348                                  unsigned int relation);
 349 int __cpufreq_driver_target(struct cpufreq_policy *policy,
 350                                    unsigned int target_freq,
 351                                    unsigned int relation);
 352 int cpufreq_register_governor(struct cpufreq_governor *governor);
 353 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 354
 355 /* CPUFREQ DEFAULT GOVERNOR */
 356 /*
 357  * Performance governor is fallback governor if any other gov failed to auto
 358  * load due latency restrictions
 359  */
 360 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
 361 extern struct cpufreq_governor cpufreq_gov_performance;
 362 #endif
 363 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 364 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_performance)
 365 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
 366 extern struct cpufreq_governor cpufreq_gov_powersave;
 367 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_powersave)
 368 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 369 extern struct cpufreq_governor cpufreq_gov_userspace;
 370 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_userspace)
 371 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
 372 extern struct cpufreq_governor cpufreq_gov_ondemand;
 373 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_ondemand)
 374 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
 375 extern struct cpufreq_governor cpufreq_gov_conservative;
 376 #define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_conservative)
 377 #endif
 378
 379 /*********************************************************************
 380  *                     FREQUENCY TABLE HELPERS                       *
 381  *********************************************************************/
 382
 383 #define CPUFREQ_ENTRY_INVALID ~0
 384 #define CPUFREQ_TABLE_END     ~1
 385
 386 struct cpufreq_frequency_table {
 387         unsigned int    driver_data; /* driver specific data, not used by core */
 388         unsigned int    frequency; /* kHz - doesn't need to be in ascending
 389                                     * order */
 390 };
 391
 392 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 393                                     struct cpufreq_frequency_table *table);
 394
 395 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 396                                    struct cpufreq_frequency_table *table);
 397
 398 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 399                                    struct cpufreq_frequency_table *table,
 400                                    unsigned int target_freq,
 401                                    unsigned int relation,
 402                                    unsigned int *index);
 403
 404 void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
 405 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
 406
 407 /* the following funtion is for cpufreq core use only */
 408 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 409
 410 /* the following are really really optional */
 411 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 412 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 413                                       unsigned int cpu);
 414 void cpufreq_frequency_table_put_attr(unsigned int cpu);
 415
 416 #endif /* _LINUX_CPUFREQ_H */