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  *
   8  * $Id: cpufreq.h,v 1.36 2003/01/20 17:31:48 db Exp $
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #ifndef _LINUX_CPUFREQ_H
  15 #define _LINUX_CPUFREQ_H
  16
  17 #include <linux/config.h>
  18 #include <linux/notifier.h>
  19 #include <linux/threads.h>
  20 #include <linux/device.h>
  21 #include <linux/kobject.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/completion.h>
  24 #include <linux/workqueue.h>
  25
  26 #define CPUFREQ_NAME_LEN 16
  27
  28
  29 /*********************************************************************
  30  *                     CPUFREQ NOTIFIER INTERFACE                    *
  31  *********************************************************************/
  32
  33 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
  34 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
  35
  36 #define CPUFREQ_TRANSITION_NOTIFIER     (0)
  37 #define CPUFREQ_POLICY_NOTIFIER         (1)
  38
  39
  40 /* if (cpufreq_driver->target) exists, the ->governor decides what frequency
  41  * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
  42  * two generic policies are available:
  43  */
  44
  45 #define CPUFREQ_POLICY_POWERSAVE        (1)
  46 #define CPUFREQ_POLICY_PERFORMANCE      (2)
  47
  48 /* Frequency values here are CPU kHz so that hardware which doesn't run
  49  * with some frequencies can complain without having to guess what per
  50  * cent / per mille means.
  51  * Maximum transition latency is in microseconds - if it's unknown,
  52  * CPUFREQ_ETERNAL shall be used.
  53  */
  54
  55 struct cpufreq_governor;
  56
  57 #define CPUFREQ_ETERNAL                 (-1)
  58 struct cpufreq_cpuinfo {
  59         unsigned int            max_freq;
  60         unsigned int            min_freq;
  61         unsigned int            transition_latency; /* in 10^(-9) s = nanoseconds */
  62 };
  63
  64 struct cpufreq_real_policy {
  65         unsigned int            min;    /* in kHz */
  66         unsigned int            max;    /* in kHz */
  67         unsigned int            policy; /* see above */
  68         struct cpufreq_governor *governor; /* see below */
  69 };
  70
  71 struct cpufreq_policy {
  72         unsigned int            cpu;    /* cpu nr */
  73         struct cpufreq_cpuinfo  cpuinfo;/* see above */
  74
  75         unsigned int            min;    /* in kHz */
  76         unsigned int            max;    /* in kHz */
  77         unsigned int            cur;    /* in kHz, only needed if cpufreq
  78                                          * governors are used */
  79         unsigned int            policy; /* see above */
  80         struct cpufreq_governor *governor; /* see below */
  81
  82         struct semaphore        lock;   /* CPU ->setpolicy or ->target may
  83                                            only be called once a time */
  84
  85         struct work_struct      update; /* if update_policy() needs to be
  86                                          * called, but you're in IRQ context */
  87
  88         struct cpufreq_real_policy      user_policy;
  89
  90         struct kobject          kobj;
  91         struct completion       kobj_unregister;
  92 };
  93
  94 #define CPUFREQ_ADJUST          (0)
  95 #define CPUFREQ_INCOMPATIBLE    (1)
  96 #define CPUFREQ_NOTIFY          (2)
  97
  98
  99 /******************** cpufreq transition notifiers *******************/
 100
 101 #define CPUFREQ_PRECHANGE       (0)
 102 #define CPUFREQ_POSTCHANGE      (1)
 103 #define CPUFREQ_RESUMECHANGE    (8)
 104
 105 struct cpufreq_freqs {
 106         unsigned int cpu;       /* cpu nr */
 107         unsigned int old;
 108         unsigned int new;
 109         u8 flags;               /* flags of cpufreq_driver, see below. */
 110 };
 111
 112
 113 /**
 114  * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 115  * @old:   old value
 116  * @div:   divisor
 117  * @mult:  multiplier
 118  *
 119  *
 120  *    new = old * mult / div
 121  */
 122 static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
 123 {
 124 #if BITS_PER_LONG == 32
 125
 126         u64 result = ((u64) old) * ((u64) mult);
 127         do_div(result, div);
 128         return (unsigned long) result;
 129
 130 #elif BITS_PER_LONG == 64
 131
 132         unsigned long result = old * ((u64) mult);
 133         result /= div;
 134         return result;
 135
 136 #endif
 137 };
 138
 139 /*********************************************************************
 140  *                          CPUFREQ GOVERNORS                        *
 141  *********************************************************************/
 142
 143 #define CPUFREQ_GOV_START  1
 144 #define CPUFREQ_GOV_STOP   2
 145 #define CPUFREQ_GOV_LIMITS 3
 146
 147 struct cpufreq_governor {
 148         char    name[CPUFREQ_NAME_LEN];
 149         int     (*governor)     (struct cpufreq_policy *policy,
 150                                  unsigned int event);
 151         struct list_head        governor_list;
 152         struct module           *owner;
 153 };
 154
 155 /* pass a target to the cpufreq driver
 156  */
 157 extern int cpufreq_driver_target(struct cpufreq_policy *policy,
 158                                  unsigned int target_freq,
 159                                  unsigned int relation);
 160 extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
 161                                    unsigned int target_freq,
 162                                    unsigned int relation);
 163
 164
 165 /* pass an event to the cpufreq governor */
 166 int cpufreq_governor(unsigned int cpu, unsigned int event);
 167
 168 int cpufreq_register_governor(struct cpufreq_governor *governor);
 169 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 170
 171
 172 /*********************************************************************
 173  *                      CPUFREQ DRIVER INTERFACE                     *
 174  *********************************************************************/
 175
 176 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 177 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 178
 179 struct freq_attr;
 180
 181 struct cpufreq_driver {
 182         struct module           *owner;
 183         char                    name[CPUFREQ_NAME_LEN];
 184         u8                      flags;
 185
 186         /* needed by all drivers */
 187         int     (*init)         (struct cpufreq_policy *policy);
 188         int     (*verify)       (struct cpufreq_policy *policy);
 189
 190         /* define one out of two */
 191         int     (*setpolicy)    (struct cpufreq_policy *policy);
 192         int     (*target)       (struct cpufreq_policy *policy,
 193                                  unsigned int target_freq,
 194                                  unsigned int relation);
 195
 196         /* should be defined, if possible */
 197         unsigned int    (*get)  (unsigned int cpu);
 198
 199         /* optional */
 200         int     (*exit)         (struct cpufreq_policy *policy);
 201         int     (*resume)       (struct cpufreq_policy *policy);
 202         struct freq_attr        **attr;
 203 };
 204
 205 /* flags */
 206
 207 #define CPUFREQ_STICKY          0x01    /* the driver isn't removed even if
 208                                          * all ->init() calls failed */
 209 #define CPUFREQ_CONST_LOOPS     0x02    /* loops_per_jiffy or other kernel
 210                                          * "constants" aren't affected by
 211                                          * frequency transitions */
 212
 213
 214 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 215 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 216
 217
 218 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);
 219
 220
 221 static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
 222 {
 223         if (policy->min < min)
 224                 policy->min = min;
 225         if (policy->max < min)
 226                 policy->max = min;
 227         if (policy->min > max)
 228                 policy->min = max;
 229         if (policy->max > max)
 230                 policy->max = max;
 231         if (policy->min > policy->max)
 232                 policy->min = policy->max;
 233         return;
 234 }
 235
 236 struct freq_attr {
 237         struct attribute attr;
 238         ssize_t (*show)(struct cpufreq_policy *, char *);
 239         ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 240 };
 241
 242
 243 /*********************************************************************
 244  *                        CPUFREQ 2.6. INTERFACE                     *
 245  *********************************************************************/
 246 int cpufreq_set_policy(struct cpufreq_policy *policy);
 247 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 248 int cpufreq_update_policy(unsigned int cpu);
 249
 250 /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
 251 unsigned int cpufreq_get(unsigned int cpu);
 252
 253 /* the proc_intf.c needs this */
 254 int cpufreq_parse_governor (char *str_governor, unsigned int *policy, struct cpufreq_governor **governor);
 255
 256
 257 /*********************************************************************
 258  *                      CPUFREQ USERSPACE GOVERNOR                   *
 259  *********************************************************************/
 260 #ifdef CONFIG_CPU_FREQ_24_API
 261
 262 int cpufreq_setmax(unsigned int cpu);
 263 int cpufreq_set(unsigned int kHz, unsigned int cpu);
 264
 265
 266 /* /proc/sys/cpu */
 267 enum {
 268         CPU_NR   = 1,           /* compatibilty reasons */
 269         CPU_NR_0 = 1,
 270         CPU_NR_1 = 2,
 271         CPU_NR_2 = 3,
 272         CPU_NR_3 = 4,
 273         CPU_NR_4 = 5,
 274         CPU_NR_5 = 6,
 275         CPU_NR_6 = 7,
 276         CPU_NR_7 = 8,
 277         CPU_NR_8 = 9,
 278         CPU_NR_9 = 10,
 279         CPU_NR_10 = 11,
 280         CPU_NR_11 = 12,
 281         CPU_NR_12 = 13,
 282         CPU_NR_13 = 14,
 283         CPU_NR_14 = 15,
 284         CPU_NR_15 = 16,
 285         CPU_NR_16 = 17,
 286         CPU_NR_17 = 18,
 287         CPU_NR_18 = 19,
 288         CPU_NR_19 = 20,
 289         CPU_NR_20 = 21,
 290         CPU_NR_21 = 22,
 291         CPU_NR_22 = 23,
 292         CPU_NR_23 = 24,
 293         CPU_NR_24 = 25,
 294         CPU_NR_25 = 26,
 295         CPU_NR_26 = 27,
 296         CPU_NR_27 = 28,
 297         CPU_NR_28 = 29,
 298         CPU_NR_29 = 30,
 299         CPU_NR_30 = 31,
 300         CPU_NR_31 = 32,
 301 };
 302
 303 /* /proc/sys/cpu/{0,1,...,(NR_CPUS-1)} */
 304 enum {
 305         CPU_NR_FREQ_MAX = 1,
 306         CPU_NR_FREQ_MIN = 2,
 307         CPU_NR_FREQ = 3,
 308 };
 309
 310 #endif /* CONFIG_CPU_FREQ_24_API */
 311
 312
 313 /*********************************************************************
 314  *                       CPUFREQ DEFAULT GOVERNOR                    *
 315  *********************************************************************/
 316
 317
 318 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 319 extern struct cpufreq_governor cpufreq_gov_performance;
 320 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_performance
 321 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 322 extern struct cpufreq_governor cpufreq_gov_userspace;
 323 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_userspace
 324 #endif
 325
 326
 327 /*********************************************************************
 328  *                     FREQUENCY TABLE HELPERS                       *
 329  *********************************************************************/
 330
 331 #define CPUFREQ_ENTRY_INVALID ~0
 332 #define CPUFREQ_TABLE_END     ~1
 333
 334 struct cpufreq_frequency_table {
 335         unsigned int    index;     /* any */
 336         unsigned int    frequency; /* kHz - doesn't need to be in ascending
 337                                     * order */
 338 };
 339
 340 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 341                                     struct cpufreq_frequency_table *table);
 342
 343 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 344                                    struct cpufreq_frequency_table *table);
 345
 346 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 347                                    struct cpufreq_frequency_table *table,
 348                                    unsigned int target_freq,
 349                                    unsigned int relation,
 350                                    unsigned int *index);
 351
 352 /* the following are really really optional */
 353 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 354
 355 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 356                                       unsigned int cpu);
 357
 358 void cpufreq_frequency_table_put_attr(unsigned int cpu);
 359
 360
 361 #endif /* _LINUX_CPUFREQ_H */