text: /*
   *  linux/include/linux/cpufreq.h
   *
   *  Copyright (C) 2001 Russell King
   *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #ifndef _LINUX_CPUFREQ_H
  #define _LINUX_CPUFREQ_H
  
  #include <linux/mutex.h>
  #include <linux/notifier.h>
  #include <linux/threads.h>
  #include <linux/kobject.h>
  #include <linux/sysfs.h>
  #include <linux/completion.h>
  #include <linux/workqueue.h>
  #include <linux/cpumask.h>
  #include <asm/div64.h>
  
  #define CPUFREQ_NAME_LEN 16
  
  
  /*********************************************************************
   *                     CPUFREQ NOTIFIER INTERFACE                    *
   *********************************************************************/
  
  #define CPUFREQ_TRANSITION_NOTIFIER	(0)
  #define CPUFREQ_POLICY_NOTIFIER		(1)
  
  #ifdef CONFIG_CPU_FREQ
  int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
  int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
  extern void disable_cpufreq(void);
  #else		/* CONFIG_CPU_FREQ */
  static inline int cpufreq_register_notifier(struct notifier_block *nb,
  						unsigned int list)
  {
  	return 0;
  }
  static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
  						unsigned int list)
  {
  	return 0;
  }
  static inline void disable_cpufreq(void) { }
  #endif		/* CONFIG_CPU_FREQ */
  
  /* if (cpufreq_driver->target) exists, the ->governor decides what frequency
   * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
   * two generic policies are available:
   */
  
  #define CPUFREQ_POLICY_POWERSAVE	(1)
  #define CPUFREQ_POLICY_PERFORMANCE	(2)
  
  /* Frequency values here are CPU kHz so that hardware which doesn't run
   * with some frequencies can complain without having to guess what per
   * cent / per mille means.
   * Maximum transition latency is in nanoseconds - if it's unknown,
   * CPUFREQ_ETERNAL shall be used.
   */
  
  struct cpufreq_governor;
  
  /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
  extern struct kobject *cpufreq_global_kobject;
  
  #define CPUFREQ_ETERNAL			(-1)
  struct cpufreq_cpuinfo {
  	unsigned int		max_freq;
  	unsigned int		min_freq;
  
  	/* in 10^(-9) s = nanoseconds */
  	unsigned int		transition_latency;
  };
  
  struct cpufreq_real_policy {
  	unsigned int		min;    /* in kHz */
  	unsigned int		max;    /* in kHz */
  	unsigned int		policy; /* see above */
  	struct cpufreq_governor	*governor; /* see below */
  };
  
  struct cpufreq_policy {
  	cpumask_var_t		cpus;	/* CPUs requiring sw coordination */
  	cpumask_var_t		related_cpus; /* CPUs with any coordination */
  	unsigned int		shared_type; /* ANY or ALL affected CPUs
  						should set cpufreq */
  	unsigned int		cpu;    /* cpu nr of registered CPU */
  	struct cpufreq_cpuinfo	cpuinfo;/* see above */
  
  	unsigned int		min;    /* in kHz */
  	unsigned int		max;    /* in kHz */
  	unsigned int		cur;    /* in kHz, only needed if cpufreq
  					 * governors are used */
  	unsigned int		policy; /* see above */
  	struct cpufreq_governor	*governor; /* see below */
  
  	struct work_struct	update; /* if update_policy() needs to be
  					 * called, but you're in IRQ context */
  
  	struct cpufreq_real_policy	user_policy;
  
  	struct kobject		kobj;
  	struct completion	kobj_unregister;
  };
  
  #define CPUFREQ_ADJUST		(0)
  #define CPUFREQ_INCOMPATIBLE	(1)
  #define CPUFREQ_NOTIFY		(2)
  #define CPUFREQ_START		(3)
  
  #define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
  #define CPUFREQ_SHARED_TYPE_HW	 (1) /* HW does needed coordination */
  #define CPUFREQ_SHARED_TYPE_ALL	 (2) /* All dependent CPUs should set freq */
  #define CPUFREQ_SHARED_TYPE_ANY	 (3) /* Freq can be set from any dependent CPU*/
  
  /******************** cpufreq transition notifiers *******************/
  
  #define CPUFREQ_PRECHANGE	(0)
  #define CPUFREQ_POSTCHANGE	(1)
  #define CPUFREQ_RESUMECHANGE	(8)
  #define CPUFREQ_SUSPENDCHANGE	(9)
  
  struct cpufreq_freqs {
  	unsigned int cpu;	/* cpu nr */
  	unsigned int old;
  	unsigned int new;
  	u8 flags;		/* flags of cpufreq_driver, see below. */
  };
  
  
  /**
   * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
   * @old:   old value
   * @div:   divisor
   * @mult:  multiplier
   *
   *
   *    new = old * mult / div
   */
  static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
  {
  #if BITS_PER_LONG == 32
  
  	u64 result = ((u64) old) * ((u64) mult);
  	do_div(result, div);
  	return (unsigned long) result;
  
  #elif BITS_PER_LONG == 64
  
  	unsigned long result = old * ((u64) mult);
  	result /= div;
  	return result;
  
  #endif
  };
  
  /*********************************************************************
   *                          CPUFREQ GOVERNORS                        *
   *********************************************************************/
  
  #define CPUFREQ_GOV_START  1
  #define CPUFREQ_GOV_STOP   2
  #define CPUFREQ_GOV_LIMITS 3
  
  struct cpufreq_governor {
  	char	name[CPUFREQ_NAME_LEN];
  	int	(*governor)	(struct cpufreq_policy *policy,
  				 unsigned int event);
  	ssize_t	(*show_setspeed)	(struct cpufreq_policy *policy,
  					 char *buf);
  	int	(*store_setspeed)	(struct cpufreq_policy *policy,
  					 unsigned int freq);
  	unsigned int max_transition_latency; /* HW must be able to switch to
  			next freq faster than this value in nano secs or we
  			will fallback to performance governor */
  	struct list_head	governor_list;
  	struct module		*owner;
  };
  
  /*
   * Pass a target to the cpufreq driver.
   */
  extern int cpufreq_driver_target(struct cpufreq_policy *policy,
  				 unsigned int target_freq,
  				 unsigned int relation);
  extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
  				   unsigned int target_freq,
  				   unsigned int relation);
  
  
  extern int __cpufreq_driver_getavg(struct cpufreq_policy *policy,
  				   unsigned int cpu);
  
  int cpufreq_register_governor(struct cpufreq_governor *governor);
  void cpufreq_unregister_governor(struct cpufreq_governor *governor);
  
  
  /*********************************************************************
   *                      CPUFREQ DRIVER INTERFACE                     *
   *********************************************************************/
  
  #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
  #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
  
  struct freq_attr;
  
  struct cpufreq_driver {
  	struct module           *owner;
  	char			name[CPUFREQ_NAME_LEN];
  	u8			flags;
  
  	/* needed by all drivers */
  	int	(*init)		(struct cpufreq_policy *policy);
  	int	(*verify)	(struct cpufreq_policy *policy);
  
  	/* define one out of two */
  	int	(*setpolicy)	(struct cpufreq_policy *policy);
  	int	(*target)	(struct cpufreq_policy *policy,
  				 unsigned int target_freq,
  				 unsigned int relation);
  
  	/* should be defined, if possible */
  	unsigned int	(*get)	(unsigned int cpu);
  
  	/* optional */
  	unsigned int (*getavg)	(struct cpufreq_policy *policy,
  				 unsigned int cpu);
  	int	(*bios_limit)	(int cpu, unsigned int *limit);
  
  	int	(*exit)		(struct cpufreq_policy *policy);
  	int	(*suspend)	(struct cpufreq_policy *policy);
  	int	(*resume)	(struct cpufreq_policy *policy);
  	struct freq_attr	**attr;
  };
  
  /* flags */
  
  #define CPUFREQ_STICKY		0x01	/* the driver isn't removed even if
  					 * all ->init() calls failed */
  #define CPUFREQ_CONST_LOOPS	0x02	/* loops_per_jiffy or other kernel
  					 * "constants" aren't affected by
  					 * frequency transitions */
  #define CPUFREQ_PM_NO_WARN	0x04	/* don't warn on suspend/resume speed
  					 * mismatches */
  
  int cpufreq_register_driver(struct cpufreq_driver *driver_data);
  int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
  
  
  void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);
  
  
  static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
  {
  	if (policy->min < min)
  		policy->min = min;
  	if (policy->max < min)
  		policy->max = min;
  	if (policy->min > max)
  		policy->min = max;
  	if (policy->max > max)
  		policy->max = max;
  	if (policy->min > policy->max)
  		policy->min = policy->max;
  	return;
  }
  
  struct freq_attr {
  	struct attribute attr;
  	ssize_t (*show)(struct cpufreq_policy *, char *);
  	ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
  };
  
  #define cpufreq_freq_attr_ro(_name)		\
  static struct freq_attr _name =			\
  __ATTR(_name, 0444, show_##_name, NULL)
  
  #define cpufreq_freq_attr_ro_perm(_name, _perm)	\
  static struct freq_attr _name =			\
  __ATTR(_name, _perm, show_##_name, NULL)
  
  #define cpufreq_freq_attr_rw(_name)		\
  static struct freq_attr _name =			\
  __ATTR(_name, 0644, show_##_name, store_##_name)
  
  struct global_attr {
  	struct attribute attr;
  	ssize_t (*show)(struct kobject *kobj,
  			struct attribute *attr, char *buf);
  	ssize_t (*store)(struct kobject *a, struct attribute *b,
  			 const char *c, size_t count);
  };
  
  #define define_one_global_ro(_name)		\
  static struct global_attr _name =		\
  __ATTR(_name, 0444, show_##_name, NULL)
  
  #define define_one_global_rw(_name)		\
  static struct global_attr _name =		\
  __ATTR(_name, 0644, show_##_name, store_##_name)
  
  
  /*********************************************************************
   *                        CPUFREQ 2.6. INTERFACE                     *
   *********************************************************************/
  int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
  int cpufreq_update_policy(unsigned int cpu);
  
  #ifdef CONFIG_CPU_FREQ
  /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
  unsigned int cpufreq_get(unsigned int cpu);
  #else
  static inline unsigned int cpufreq_get(unsigned int cpu)
  {
  	return 0;
  }
  #endif
  
  /* query the last known CPU freq (in kHz). If zero, cpufreq couldn't detect it */
  #ifdef CONFIG_CPU_FREQ
  unsigned int cpufreq_quick_get(unsigned int cpu);
  unsigned int cpufreq_quick_get_max(unsigned int cpu);
  #else
  static inline unsigned int cpufreq_quick_get(unsigned int cpu)
  {
  	return 0;
  }
  static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
  {
  	return 0;
  }
  #endif
  
  
  /*********************************************************************
   *                       CPUFREQ DEFAULT GOVERNOR                    *
   *********************************************************************/
  
  
  /*
    Performance governor is fallback governor if any other gov failed to
    auto load due latency restrictions
  */
  #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
  extern struct cpufreq_governor cpufreq_gov_performance;
  #endif
  #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_performance)
  #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
  extern struct cpufreq_governor cpufreq_gov_powersave;
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_powersave)
  #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
  extern struct cpufreq_governor cpufreq_gov_userspace;
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_userspace)
  #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
  extern struct cpufreq_governor cpufreq_gov_ondemand;
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_ondemand)
  #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
  extern struct cpufreq_governor cpufreq_gov_conservative;
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_conservative)
  #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE)
  extern struct cpufreq_governor cpufreq_gov_interactive;
  #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_interactive)
  #endif
  
  
  /*********************************************************************
   *                     FREQUENCY TABLE HELPERS                       *
   *********************************************************************/
  
  #define CPUFREQ_ENTRY_INVALID ~0
  #define CPUFREQ_TABLE_END     ~1
  
  struct cpufreq_frequency_table {
  	unsigned int	index;     /* any */
  	unsigned int	frequency; /* kHz - doesn't need to be in ascending
  				    * order */
  };
  
  int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  				    struct cpufreq_frequency_table *table);
  
  int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  				   struct cpufreq_frequency_table *table);
  
  int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  				   struct cpufreq_frequency_table *table,
  				   unsigned int target_freq,
  				   unsigned int relation,
  				   unsigned int *index);
  
  /* the following 3 funtions are for cpufreq core use only */
  struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
  struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
  void   cpufreq_cpu_put(struct cpufreq_policy *data);
  
  /* the following are really really optional */
  extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
  
  void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
  				      unsigned int cpu);
  
  void cpufreq_frequency_table_put_attr(unsigned int cpu);
  
  
  #endif /* _LINUX_CPUFREQ_H */
  