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