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linux-next/include/linux/cpufreq.h
Viresh Kumar 1c03a2d04d cpufreq: add support for intermediate (stable) frequencies 
Douglas Anderson, recently pointed out an interesting problem due to which
udelay() was expiring earlier than it should.

While transitioning between frequencies few platforms may temporarily switch to
a stable frequency, waiting for the main PLL to stabilize.

For example: When we transition between very low frequencies on exynos, like
between 200MHz and 300MHz, we may temporarily switch to a PLL running at 800MHz.
No CPUFREQ notification is sent for that. That means there's a period of time
when we're running at 800MHz but loops_per_jiffy is calibrated at between 200MHz
and 300MHz. And so udelay behaves badly.

To get this fixed in a generic way, introduce another set of callbacks
get_intermediate() and target_intermediate(), only for drivers with
target_index() and CPUFREQ_ASYNC_NOTIFICATION unset.

get_intermediate() should return a stable intermediate frequency platform wants
to switch to, and target_intermediate() should set CPU to that frequency,
before jumping to the frequency corresponding to 'index'. Core will take care of
sending notifications and driver doesn't have to handle them in
target_intermediate() or target_index().

NOTE: ->target_index() should restore to policy->restore_freq in case of
failures as core would send notifications for that.

Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-05 23:32:29 +02:00

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/*
* 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/clk.h>
#include <linux/cpumask.h>
#include <linux/completion.h>
#include <linux/kobject.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/sysfs.h>
/*********************************************************************
* CPUFREQ INTERFACE *
*********************************************************************/
/*
* Frequency values here are CPU kHz
*
* Maximum transition latency is in nanoseconds - if it's unknown,
* CPUFREQ_ETERNAL shall be used.
*/
#define CPUFREQ_ETERNAL (-1)
#define CPUFREQ_NAME_LEN 16
/* Print length for names. Extra 1 space for accomodating '\n' in prints */
#define CPUFREQ_NAME_PLEN (CPUFREQ_NAME_LEN + 1)
struct cpufreq_governor;
struct cpufreq_freqs {
unsigned int cpu; /* cpu nr */
unsigned int old;
unsigned int new;
u8 flags; /* flags of cpufreq_driver, see below. */
};
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 {
/* CPUs sharing clock, require sw coordination */
cpumask_var_t cpus; /* Online CPUs only */
cpumask_var_t related_cpus; /* Online + Offline CPUs */
unsigned int shared_type; /* ACPI: ANY or ALL affected CPUs
should set cpufreq */
unsigned int cpu; /* cpu nr of CPU managing this policy */
unsigned int last_cpu; /* cpu nr of previous CPU that managed
* this policy */
struct clk *clk;
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 restore_freq; /* = policy->cur before transition */
unsigned int suspend_freq; /* freq to set during suspend */
unsigned int policy; /* see above */
struct cpufreq_governor *governor; /* see below */
void *governor_data;
bool governor_enabled; /* governor start/stop flag */
struct work_struct update; /* if update_policy() needs to be
* called, but you're in IRQ context */
struct cpufreq_real_policy user_policy;
struct cpufreq_frequency_table *freq_table;
struct list_head policy_list;
struct kobject kobj;
struct completion kobj_unregister;
/*
* The rules for this semaphore:
* - Any routine that wants to read from the policy structure will
* do a down_read on this semaphore.
* - Any routine that will write to the policy structure and/or may take away
* the policy altogether (eg. CPU hotplug), will hold this lock in write
* mode before doing so.
*
* Additional rules:
* - Lock should not be held across
* __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
*/
struct rw_semaphore rwsem;
/* Synchronization for frequency transitions */
bool transition_ongoing; /* Tracks transition status */
spinlock_t transition_lock;
wait_queue_head_t transition_wait;
struct task_struct *transition_task; /* Task which is doing the transition */
};
/* Only for ACPI */
#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*/
#ifdef CONFIG_CPU_FREQ
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
void cpufreq_cpu_put(struct cpufreq_policy *policy);
#else
static inline struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
return NULL;
}
static inline void cpufreq_cpu_put(struct cpufreq_policy *policy) { }
#endif
static inline bool policy_is_shared(struct cpufreq_policy *policy)
{
return cpumask_weight(policy->cpus) > 1;
}
/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
extern struct kobject *cpufreq_global_kobject;
int cpufreq_get_global_kobject(void);
void cpufreq_put_global_kobject(void);
int cpufreq_sysfs_create_file(const struct attribute *attr);
void cpufreq_sysfs_remove_file(const struct attribute *attr);
#ifdef CONFIG_CPU_FREQ
unsigned int cpufreq_get(unsigned int cpu);
unsigned int cpufreq_quick_get(unsigned int cpu);
unsigned int cpufreq_quick_get_max(unsigned int cpu);
void disable_cpufreq(void);
u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
int cpufreq_update_policy(unsigned int cpu);
bool have_governor_per_policy(void);
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
#else
static inline unsigned int cpufreq_get(unsigned int cpu)
{
return 0;
}
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;
}
static inline void disable_cpufreq(void) { }
#endif
/*********************************************************************
* 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 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)
struct cpufreq_driver {
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);
/*
* On failure, should always restore frequency to policy->restore_freq
* (i.e. old freq).
*/
int (*target) (struct cpufreq_policy *policy, /* Deprecated */
unsigned int target_freq,
unsigned int relation);
int (*target_index) (struct cpufreq_policy *policy,
unsigned int index);
/*
* Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION
* unset.
*
* get_intermediate should return a stable intermediate frequency
* platform wants to switch to and target_intermediate() should set CPU
* to to that frequency, before jumping to the frequency corresponding
* to 'index'. Core will take care of sending notifications and driver
* doesn't have to handle them in target_intermediate() or
* target_index().
*
* Drivers can return '0' from get_intermediate() in case they don't
* wish to switch to intermediate frequency for some target frequency.
* In that case core will directly call ->target_index().
*/
unsigned int (*get_intermediate)(struct cpufreq_policy *policy,
unsigned int index);
int (*target_intermediate)(struct cpufreq_policy *policy,
unsigned int index);
/* should be defined, if possible */
unsigned int (*get) (unsigned int cpu);
/* optional */
int (*bios_limit) (int cpu, unsigned int *limit);
int (*exit) (struct cpufreq_policy *policy);
void (*stop_cpu) (struct cpufreq_policy *policy);
int (*suspend) (struct cpufreq_policy *policy);
int (*resume) (struct cpufreq_policy *policy);
struct freq_attr **attr;
/* platform specific boost support code */
bool boost_supported;
bool boost_enabled;
int (*set_boost) (int state);
};
/* flags */
#define CPUFREQ_STICKY (1 << 0) /* driver isn't removed even if
all ->init() calls failed */
#define CPUFREQ_CONST_LOOPS (1 << 1) /* loops_per_jiffy or other
kernel "constants" aren't
affected by frequency
transitions */
#define CPUFREQ_PM_NO_WARN (1 << 2) /* don't warn on suspend/resume
speed mismatches */
/*
* This should be set by platforms having multiple clock-domains, i.e.
* supporting multiple policies. With this sysfs directories of governor would
* be created in cpu/cpu<num>/cpufreq/ directory and so they can use the same
* governor with different tunables for different clusters.
*/
#define CPUFREQ_HAVE_GOVERNOR_PER_POLICY (1 << 3)
/*
* Driver will do POSTCHANGE notifications from outside of their ->target()
* routine and so must set cpufreq_driver->flags with this flag, so that core
* can handle them specially.
*/
#define CPUFREQ_ASYNC_NOTIFICATION (1 << 4)
/*
* Set by drivers which want cpufreq core to check if CPU is running at a
* frequency present in freq-table exposed by the driver. For these drivers if
* CPU is found running at an out of table freq, we will try to set it to a freq
* from the table. And if that fails, we will stop further boot process by
* issuing a BUG_ON().
*/
#define CPUFREQ_NEED_INITIAL_FREQ_CHECK (1 << 5)
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
const char *cpufreq_get_current_driver(void);
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;
}
static inline void
cpufreq_verify_within_cpu_limits(struct cpufreq_policy *policy)
{
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
}
#ifdef CONFIG_CPU_FREQ
void cpufreq_suspend(void);
void cpufreq_resume(void);
int cpufreq_generic_suspend(struct cpufreq_policy *policy);
#else
static inline void cpufreq_suspend(void) {}
static inline void cpufreq_resume(void) {}
#endif
/*********************************************************************
* CPUFREQ NOTIFIER INTERFACE *
*********************************************************************/
#define CPUFREQ_TRANSITION_NOTIFIER (0)
#define CPUFREQ_POLICY_NOTIFIER (1)
/* Transition notifiers */
#define CPUFREQ_PRECHANGE (0)
#define CPUFREQ_POSTCHANGE (1)
/* Policy Notifiers */
#define CPUFREQ_ADJUST (0)
#define CPUFREQ_INCOMPATIBLE (1)
#define CPUFREQ_NOTIFY (2)
#define CPUFREQ_START (3)
#define CPUFREQ_UPDATE_POLICY_CPU (4)
#define CPUFREQ_CREATE_POLICY (5)
#define CPUFREQ_REMOVE_POLICY (6)
#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);
void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs);
void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int transition_failed);
#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;
}
#endif /* !CONFIG_CPU_FREQ */
/**
* 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 *
*********************************************************************/
/*
* 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)
/* Governor Events */
#define CPUFREQ_GOV_START 1
#define CPUFREQ_GOV_STOP 2
#define CPUFREQ_GOV_LIMITS 3
#define CPUFREQ_GOV_POLICY_INIT 4
#define CPUFREQ_GOV_POLICY_EXIT 5
struct cpufreq_governor {
char name[CPUFREQ_NAME_LEN];
int initialized;
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 */
int cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation);
int __cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation);
int cpufreq_register_governor(struct cpufreq_governor *governor);
void cpufreq_unregister_governor(struct cpufreq_governor *governor);
/* 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)
#endif
/*********************************************************************
* FREQUENCY TABLE HELPERS *
*********************************************************************/
/* Special Values of .frequency field */
#define CPUFREQ_ENTRY_INVALID ~0
#define CPUFREQ_TABLE_END ~1
/* Special Values of .flags field */
#define CPUFREQ_BOOST_FREQ (1 << 0)
struct cpufreq_frequency_table {
unsigned int flags;
unsigned int driver_data; /* driver specific data, not used by core */
unsigned int frequency; /* kHz - doesn't need to be in ascending
* order */
};
#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP)
int dev_pm_opp_init_cpufreq_table(struct device *dev,
struct cpufreq_frequency_table **table);
void dev_pm_opp_free_cpufreq_table(struct device *dev,
struct cpufreq_frequency_table **table);
#else
static inline int dev_pm_opp_init_cpufreq_table(struct device *dev,
struct cpufreq_frequency_table
**table)
{
return -EINVAL;
}
static inline void dev_pm_opp_free_cpufreq_table(struct device *dev,
struct cpufreq_frequency_table
**table)
{
}
#endif
static inline bool cpufreq_next_valid(struct cpufreq_frequency_table **pos)
{
while ((*pos)->frequency != CPUFREQ_TABLE_END)
if ((*pos)->frequency != CPUFREQ_ENTRY_INVALID)
return true;
else
(*pos)++;
return false;
}
/*
* cpufreq_for_each_entry - iterate over a cpufreq_frequency_table
* @pos: the cpufreq_frequency_table * to use as a loop cursor.
* @table: the cpufreq_frequency_table * to iterate over.
*/
#define cpufreq_for_each_entry(pos, table) \
for (pos = table; pos->frequency != CPUFREQ_TABLE_END; pos++)
/*
* cpufreq_for_each_valid_entry - iterate over a cpufreq_frequency_table
* excluding CPUFREQ_ENTRY_INVALID frequencies.
* @pos: the cpufreq_frequency_table * to use as a loop cursor.
* @table: the cpufreq_frequency_table * to iterate over.
*/
#define cpufreq_for_each_valid_entry(pos, table) \
for (pos = table; cpufreq_next_valid(&pos); pos++)
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_generic_frequency_table_verify(struct cpufreq_policy *policy);
int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table,
unsigned int target_freq,
unsigned int relation,
unsigned int *index);
int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
unsigned int freq);
ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
#ifdef CONFIG_CPU_FREQ
int cpufreq_boost_trigger_state(int state);
int cpufreq_boost_supported(void);
int cpufreq_boost_enabled(void);
#else
static inline int cpufreq_boost_trigger_state(int state)
{
return 0;
}
static inline int cpufreq_boost_supported(void)
{
return 0;
}
static inline int cpufreq_boost_enabled(void)
{
return 0;
}
#endif
/* the following funtion is for cpufreq core use only */
struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
/* the following are really really optional */
extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
extern struct freq_attr *cpufreq_generic_attr[];
int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table);
unsigned int cpufreq_generic_get(unsigned int cpu);
int cpufreq_generic_init(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table,
unsigned int transition_latency);
#endif /* _LINUX_CPUFREQ_H */
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