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 #include <linux/cpumask.h>
  26
  27 #define CPUFREQ_NAME_LEN 16
  28
  29
  30 /*********************************************************************
  31  *                     CPUFREQ NOTIFIER INTERFACE                    *
  32  *********************************************************************/
  33
  34 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
  35 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
  36
  37 #define CPUFREQ_TRANSITION_NOTIFIER     (0)
  38 #define CPUFREQ_POLICY_NOTIFIER         (1)
  39
  40
  41 /* if (cpufreq_driver->target) exists, the ->governor decides what frequency
  42  * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
  43  * two generic policies are available:
  44  */
  45
  46 #define CPUFREQ_POLICY_POWERSAVE        (1)
  47 #define CPUFREQ_POLICY_PERFORMANCE      (2)
  48
  49 /* Frequency values here are CPU kHz so that hardware which doesn't run
  50  * with some frequencies can complain without having to guess what per
  51  * cent / per mille means.
  52  * Maximum transition latency is in microseconds - if it's unknown,
  53  * CPUFREQ_ETERNAL shall be used.
  54  */
  55
  56 struct cpufreq_governor;
  57
  58 #define CPUFREQ_ETERNAL                 (-1)
  59 struct cpufreq_cpuinfo {
  60         unsigned int            max_freq;
  61         unsigned int            min_freq;
  62         unsigned int            transition_latency; /* in 10^(-9) s = nanoseconds */
  63 };
  64
  65 struct cpufreq_real_policy {
  66         unsigned int            min;    /* in kHz */
  67         unsigned int            max;    /* in kHz */
  68         unsigned int            policy; /* see above */
  69         struct cpufreq_governor *governor; /* see below */
  70 };
  71
  72 struct cpufreq_policy {
  73         cpumask_t               cpus;   /* affected CPUs */
  74         unsigned int            cpu;    /* cpu nr of registered CPU */
  75         struct cpufreq_cpuinfo  cpuinfo;/* see above */
  76
  77         unsigned int            min;    /* in kHz */
  78         unsigned int            max;    /* in kHz */
  79         unsigned int            cur;    /* in kHz, only needed if cpufreq
  80                                          * governors are used */
  81         unsigned int            policy; /* see above */
  82         struct cpufreq_governor *governor; /* see below */
  83
  84         struct semaphore        lock;   /* CPU ->setpolicy or ->target may
  85                                            only be called once a time */
  86
  87         struct work_struct      update; /* if update_policy() needs to be
  88                                          * called, but you're in IRQ context */
  89
  90         struct cpufreq_real_policy      user_policy;
  91
  92         struct kobject          kobj;
  93         struct completion       kobj_unregister;
  94 };
  95
  96 #define CPUFREQ_ADJUST          (0)
  97 #define CPUFREQ_INCOMPATIBLE    (1)
  98 #define CPUFREQ_NOTIFY          (2)
  99
 100
 101 /******************** cpufreq transition notifiers *******************/
 102
 103 #define CPUFREQ_PRECHANGE       (0)
 104 #define CPUFREQ_POSTCHANGE      (1)
 105 #define CPUFREQ_RESUMECHANGE    (8)
 106
 107 struct cpufreq_freqs {
 108         unsigned int cpu;       /* cpu nr */
 109         unsigned int old;
 110         unsigned int new;
 111         u8 flags;               /* flags of cpufreq_driver, see below. */
 112 };
 113
 114
 115 /**
 116  * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 117  * @old:   old value
 118  * @div:   divisor
 119  * @mult:  multiplier
 120  *
 121  *
 122  *    new = old * mult / div
 123  */
 124 static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
 125 {
 126 #if BITS_PER_LONG == 32
 127
 128         u64 result = ((u64) old) * ((u64) mult);
 129         do_div(result, div);
 130         return (unsigned long) result;
 131
 132 #elif BITS_PER_LONG == 64
 133
 134         unsigned long result = old * ((u64) mult);
 135         result /= div;
 136         return result;
 137
 138 #endif
 139 };
 140
 141 /*********************************************************************
 142  *                          CPUFREQ GOVERNORS                        *
 143  *********************************************************************/
 144
 145 #define CPUFREQ_GOV_START  1
 146 #define CPUFREQ_GOV_STOP   2
 147 #define CPUFREQ_GOV_LIMITS 3
 148
 149 struct cpufreq_governor {
 150         char    name[CPUFREQ_NAME_LEN];
 151         int     (*governor)     (struct cpufreq_policy *policy,
 152                                  unsigned int event);
 153         struct list_head        governor_list;
 154         struct module           *owner;
 155 };
 156
 157 /* pass a target to the cpufreq driver
 158  */
 159 extern int cpufreq_driver_target(struct cpufreq_policy *policy,
 160                                  unsigned int target_freq,
 161                                  unsigned int relation);
 162 extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
 163                                    unsigned int target_freq,
 164                                    unsigned int relation);
 165
 166
 167 /* pass an event to the cpufreq governor */
 168 int cpufreq_governor(unsigned int cpu, unsigned int event);
 169
 170 int cpufreq_register_governor(struct cpufreq_governor *governor);
 171 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 172
 173
 174 /*********************************************************************
 175  *                      CPUFREQ DRIVER INTERFACE                     *
 176  *********************************************************************/
 177
 178 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 179 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 180
 181 struct freq_attr;
 182
 183 struct cpufreq_driver {
 184         struct module           *owner;
 185         char                    name[CPUFREQ_NAME_LEN];
 186         u8                      flags;
 187
 188         /* needed by all drivers */
 189         int     (*init)         (struct cpufreq_policy *policy);
 190         int     (*verify)       (struct cpufreq_policy *policy);
 191
 192         /* define one out of two */
 193         int     (*setpolicy)    (struct cpufreq_policy *policy);
 194         int     (*target)       (struct cpufreq_policy *policy,
 195                                  unsigned int target_freq,
 196                                  unsigned int relation);
 197
 198         /* should be defined, if possible */
 199         unsigned int    (*get)  (unsigned int cpu);
 200
 201         /* optional */
 202         int     (*exit)         (struct cpufreq_policy *policy);
 203         int     (*resume)       (struct cpufreq_policy *policy);
 204         struct freq_attr        **attr;
 205 };
 206
 207 /* flags */
 208
 209 #define CPUFREQ_STICKY          0x01    /* the driver isn't removed even if
 210                                          * all ->init() calls failed */
 211 #define CPUFREQ_CONST_LOOPS     0x02    /* loops_per_jiffy or other kernel
 212                                          * "constants" aren't affected by
 213                                          * frequency transitions */
 214
 215
 216 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 217 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 218
 219
 220 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);
 221
 222
 223 static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
 224 {
 225         if (policy->min < min)
 226                 policy->min = min;
 227         if (policy->max < min)
 228                 policy->max = min;
 229         if (policy->min > max)
 230                 policy->min = max;
 231         if (policy->max > max)
 232                 policy->max = max;
 233         if (policy->min > policy->max)
 234                 policy->min = policy->max;
 235         return;
 236 }
 237
 238 struct freq_attr {
 239         struct attribute attr;
 240         ssize_t (*show)(struct cpufreq_policy *, char *);
 241         ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 242 };
 243
 244
 245 /*********************************************************************
 246  *                        CPUFREQ 2.6. INTERFACE                     *
 247  *********************************************************************/
 248 int cpufreq_set_policy(struct cpufreq_policy *policy);
 249 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 250 int cpufreq_update_policy(unsigned int cpu);
 251
 252 /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
 253 unsigned int cpufreq_get(unsigned int cpu);
 254
 255
 256 /*********************************************************************
 257  *                       CPUFREQ DEFAULT GOVERNOR                    *
 258  *********************************************************************/
 259
 260
 261 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 262 extern struct cpufreq_governor cpufreq_gov_performance;
 263 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_performance
 264 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 265 extern struct cpufreq_governor cpufreq_gov_userspace;
 266 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_userspace
 267 #endif
 268
 269
 270 /*********************************************************************
 271  *                     FREQUENCY TABLE HELPERS                       *
 272  *********************************************************************/
 273
 274 #define CPUFREQ_ENTRY_INVALID ~0
 275 #define CPUFREQ_TABLE_END     ~1
 276
 277 struct cpufreq_frequency_table {
 278         unsigned int    index;     /* any */
 279         unsigned int    frequency; /* kHz - doesn't need to be in ascending
 280                                     * order */
 281 };
 282
 283 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 284                                     struct cpufreq_frequency_table *table);
 285
 286 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 287                                    struct cpufreq_frequency_table *table);
 288
 289 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 290                                    struct cpufreq_frequency_table *table,
 291                                    unsigned int target_freq,
 292                                    unsigned int relation,
 293                                    unsigned int *index);
 294
 295 /* the following 3 funtions are for cpufreq core use only */
 296 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 297 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
 298 void   cpufreq_cpu_put (struct cpufreq_policy *data);
 299
 300 /* the following are really really optional */
 301 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 302
 303 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 304                                       unsigned int cpu);
 305
 306 void cpufreq_frequency_table_put_attr(unsigned int cpu);
 307
 308
 309 /*********************************************************************
 310  *                     UNIFIED DEBUG HELPERS                         *
 311  *********************************************************************/
 312
 313 #define CPUFREQ_DEBUG_CORE      1
 314 #define CPUFREQ_DEBUG_DRIVER    2
 315 #define CPUFREQ_DEBUG_GOVERNOR  4
 316
 317 #ifdef CONFIG_CPU_FREQ_DEBUG
 318
 319 extern void cpufreq_debug_printk(unsigned int type, const char *prefix,
 320                                  const char *fmt, ...);
 321
 322 #else
 323
 324 #define cpufreq_debug_printk(msg...) do { } while(0)
 325
 326 #endif /* CONFIG_CPU_FREQ_DEBUG */
 327
 328 #endif /* _LINUX_CPUFREQ_H */