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 #include <asm/div64.h>
  27
  28 #define CPUFREQ_NAME_LEN 16
  29
  30
  31 /*********************************************************************
  32  *                     CPUFREQ NOTIFIER INTERFACE                    *
  33  *********************************************************************/
  34
  35 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
  36 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
  37
  38 #define CPUFREQ_TRANSITION_NOTIFIER     (0)
  39 #define CPUFREQ_POLICY_NOTIFIER         (1)
  40
  41
  42 /* if (cpufreq_driver->target) exists, the ->governor decides what frequency
  43  * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
  44  * two generic policies are available:
  45  */
  46
  47 #define CPUFREQ_POLICY_POWERSAVE        (1)
  48 #define CPUFREQ_POLICY_PERFORMANCE      (2)
  49
  50 /* Frequency values here are CPU kHz so that hardware which doesn't run
  51  * with some frequencies can complain without having to guess what per
  52  * cent / per mille means.
  53  * Maximum transition latency is in nanoseconds - if it's unknown,
  54  * CPUFREQ_ETERNAL shall be used.
  55  */
  56
  57 struct cpufreq_governor;
  58
  59 #define CPUFREQ_ETERNAL                 (-1)
  60 struct cpufreq_cpuinfo {
  61         unsigned int            max_freq;
  62         unsigned int            min_freq;
  63         unsigned int            transition_latency; /* in 10^(-9) s = nanoseconds */
  64 };
  65
  66 struct cpufreq_real_policy {
  67         unsigned int            min;    /* in kHz */
  68         unsigned int            max;    /* in kHz */
  69         unsigned int            policy; /* see above */
  70         struct cpufreq_governor *governor; /* see below */
  71 };
  72
  73 struct cpufreq_policy {
  74         cpumask_t               cpus;   /* affected CPUs */
  75         unsigned int            cpu;    /* cpu nr of registered CPU */
  76         struct cpufreq_cpuinfo  cpuinfo;/* see above */
  77
  78         unsigned int            min;    /* in kHz */
  79         unsigned int            max;    /* in kHz */
  80         unsigned int            cur;    /* in kHz, only needed if cpufreq
  81                                          * governors are used */
  82         unsigned int            policy; /* see above */
  83         struct cpufreq_governor *governor; /* see below */
  84
  85         struct semaphore        lock;   /* CPU ->setpolicy or ->target may
  86                                            only be called once a time */
  87
  88         struct work_struct      update; /* if update_policy() needs to be
  89                                          * called, but you're in IRQ context */
  90
  91         struct cpufreq_real_policy      user_policy;
  92
  93         struct kobject          kobj;
  94         struct completion       kobj_unregister;
  95 };
  96
  97 #define CPUFREQ_ADJUST          (0)
  98 #define CPUFREQ_INCOMPATIBLE    (1)
  99 #define CPUFREQ_NOTIFY          (2)
 100
 101
 102 /******************** cpufreq transition notifiers *******************/
 103
 104 #define CPUFREQ_PRECHANGE       (0)
 105 #define CPUFREQ_POSTCHANGE      (1)
 106 #define CPUFREQ_RESUMECHANGE    (8)
 107 #define CPUFREQ_SUSPENDCHANGE   (9)
 108
 109 struct cpufreq_freqs {
 110         unsigned int cpu;       /* cpu nr */
 111         unsigned int old;
 112         unsigned int new;
 113         u8 flags;               /* flags of cpufreq_driver, see below. */
 114 };
 115
 116
 117 /**
 118  * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 119  * @old:   old value
 120  * @div:   divisor
 121  * @mult:  multiplier
 122  *
 123  *
 124  *    new = old * mult / div
 125  */
 126 static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
 127 {
 128 #if BITS_PER_LONG == 32
 129
 130         u64 result = ((u64) old) * ((u64) mult);
 131         do_div(result, div);
 132         return (unsigned long) result;
 133
 134 #elif BITS_PER_LONG == 64
 135
 136         unsigned long result = old * ((u64) mult);
 137         result /= div;
 138         return result;
 139
 140 #endif
 141 };
 142
 143 /*********************************************************************
 144  *                          CPUFREQ GOVERNORS                        *
 145  *********************************************************************/
 146
 147 #define CPUFREQ_GOV_START  1
 148 #define CPUFREQ_GOV_STOP   2
 149 #define CPUFREQ_GOV_LIMITS 3
 150
 151 struct cpufreq_governor {
 152         char    name[CPUFREQ_NAME_LEN];
 153         int     (*governor)     (struct cpufreq_policy *policy,
 154                                  unsigned int event);
 155         struct list_head        governor_list;
 156         struct module           *owner;
 157 };
 158
 159 /* pass a target to the cpufreq driver
 160  */
 161 extern int cpufreq_driver_target(struct cpufreq_policy *policy,
 162                                  unsigned int target_freq,
 163                                  unsigned int relation);
 164 extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
 165                                    unsigned int target_freq,
 166                                    unsigned int relation);
 167
 168
 169 /* pass an event to the cpufreq governor */
 170 int cpufreq_governor(unsigned int cpu, unsigned int event);
 171
 172 int cpufreq_register_governor(struct cpufreq_governor *governor);
 173 void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 174
 175
 176 /*********************************************************************
 177  *                      CPUFREQ DRIVER INTERFACE                     *
 178  *********************************************************************/
 179
 180 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 181 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 182
 183 struct freq_attr;
 184
 185 struct cpufreq_driver {
 186         struct module           *owner;
 187         char                    name[CPUFREQ_NAME_LEN];
 188         u8                      flags;
 189
 190         /* needed by all drivers */
 191         int     (*init)         (struct cpufreq_policy *policy);
 192         int     (*verify)       (struct cpufreq_policy *policy);
 193
 194         /* define one out of two */
 195         int     (*setpolicy)    (struct cpufreq_policy *policy);
 196         int     (*target)       (struct cpufreq_policy *policy,
 197                                  unsigned int target_freq,
 198                                  unsigned int relation);
 199
 200         /* should be defined, if possible */
 201         unsigned int    (*get)  (unsigned int cpu);
 202
 203         /* optional */
 204         int     (*exit)         (struct cpufreq_policy *policy);
 205         int     (*suspend)      (struct cpufreq_policy *policy, pm_message_t pmsg);
 206         int     (*resume)       (struct cpufreq_policy *policy);
 207         struct freq_attr        **attr;
 208 };
 209
 210 /* flags */
 211
 212 #define CPUFREQ_STICKY          0x01    /* the driver isn't removed even if
 213                                          * all ->init() calls failed */
 214 #define CPUFREQ_CONST_LOOPS     0x02    /* loops_per_jiffy or other kernel
 215                                          * "constants" aren't affected by
 216                                          * frequency transitions */
 217 #define CPUFREQ_PM_NO_WARN      0x04    /* don't warn on suspend/resume speed
 218                                          * mismatches */
 219
 220 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 221 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 222
 223
 224 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);
 225
 226
 227 static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
 228 {
 229         if (policy->min < min)
 230                 policy->min = min;
 231         if (policy->max < min)
 232                 policy->max = min;
 233         if (policy->min > max)
 234                 policy->min = max;
 235         if (policy->max > max)
 236                 policy->max = max;
 237         if (policy->min > policy->max)
 238                 policy->min = policy->max;
 239         return;
 240 }
 241
 242 struct freq_attr {
 243         struct attribute attr;
 244         ssize_t (*show)(struct cpufreq_policy *, char *);
 245         ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 246 };
 247
 248
 249 /*********************************************************************
 250  *                        CPUFREQ 2.6. INTERFACE                     *
 251  *********************************************************************/
 252 int cpufreq_set_policy(struct cpufreq_policy *policy);
 253 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 254 int cpufreq_update_policy(unsigned int cpu);
 255
 256 /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
 257 unsigned int cpufreq_get(unsigned int cpu);
 258
 259
 260 /*********************************************************************
 261  *                       CPUFREQ DEFAULT GOVERNOR                    *
 262  *********************************************************************/
 263
 264
 265 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 266 extern struct cpufreq_governor cpufreq_gov_performance;
 267 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_performance
 268 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 269 extern struct cpufreq_governor cpufreq_gov_userspace;
 270 #define CPUFREQ_DEFAULT_GOVERNOR        &cpufreq_gov_userspace
 271 #endif
 272
 273
 274 /*********************************************************************
 275  *                     FREQUENCY TABLE HELPERS                       *
 276  *********************************************************************/
 277
 278 #define CPUFREQ_ENTRY_INVALID ~0
 279 #define CPUFREQ_TABLE_END     ~1
 280
 281 struct cpufreq_frequency_table {
 282         unsigned int    index;     /* any */
 283         unsigned int    frequency; /* kHz - doesn't need to be in ascending
 284                                     * order */
 285 };
 286
 287 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 288                                     struct cpufreq_frequency_table *table);
 289
 290 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 291                                    struct cpufreq_frequency_table *table);
 292
 293 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 294                                    struct cpufreq_frequency_table *table,
 295                                    unsigned int target_freq,
 296                                    unsigned int relation,
 297                                    unsigned int *index);
 298
 299 /* the following 3 funtions are for cpufreq core use only */
 300 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 301 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
 302 void   cpufreq_cpu_put (struct cpufreq_policy *data);
 303
 304 /* the following are really really optional */
 305 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 306
 307 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 308                                       unsigned int cpu);
 309
 310 void cpufreq_frequency_table_put_attr(unsigned int cpu);
 311
 312
 313 /*********************************************************************
 314  *                     UNIFIED DEBUG HELPERS                         *
 315  *********************************************************************/
 316
 317 #define CPUFREQ_DEBUG_CORE      1
 318 #define CPUFREQ_DEBUG_DRIVER    2
 319 #define CPUFREQ_DEBUG_GOVERNOR  4
 320
 321 #ifdef CONFIG_CPU_FREQ_DEBUG
 322
 323 extern void cpufreq_debug_printk(unsigned int type, const char *prefix,
 324                                  const char *fmt, ...);
 325
 326 #else
 327
 328 #define cpufreq_debug_printk(msg...) do { } while(0)
 329
 330 #endif /* CONFIG_CPU_FREQ_DEBUG */
 331
 332 #endif /* _LINUX_CPUFREQ_H */