diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-03-30 03:47:49 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-04-02 01:09:03 +0200 |
| commit | b7898fda5bc7e786e76ce24fbd2ec993b08ec518 (patch) | |
| tree | 2bf721763c79a7fe0eca25349a549c52ba6ce483 /include/linux/cpufreq.h | |
| parent | 379480d8258056bfdbaa65e4d3f024bb5b34b52b (diff) | |
cpufreq: Support for fast frequency switching
Modify the ACPI cpufreq driver to provide a method for switching
CPU frequencies from interrupt context and update the cpufreq core
to support that method if available.
Introduce a new cpufreq driver callback, ->fast_switch, to be
invoked for frequency switching from interrupt context by (future)
governors supporting that feature via (new) helper function
cpufreq_driver_fast_switch().
Add two new policy flags, fast_switch_possible, to be set by the
cpufreq driver if fast frequency switching can be used for the
given policy and fast_switch_enabled, to be set by the governor
if it is going to use fast frequency switching for the given
policy. Also add a helper for setting the latter.
Since fast frequency switching is inherently incompatible with
cpufreq transition notifiers, make it possible to set the
fast_switch_enabled only if there are no transition notifiers
already registered and make the registration of new transition
notifiers fail if fast_switch_enabled is set for at least one
policy.
Implement the ->fast_switch callback in the ACPI cpufreq driver
and make it set fast_switch_possible during policy initialization
as appropriate.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'include/linux/cpufreq.h')
| -rw-r--r-- | include/linux/cpufreq.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 2b4f248b8ef1..55e69ebb035c 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -102,6 +102,17 @@ struct cpufreq_policy { */ struct rw_semaphore rwsem; + /* + * Fast switch flags: + * - fast_switch_possible should be set by the driver if it can + * guarantee that frequency can be changed on any CPU sharing the + * policy and that the change will affect all of the policy CPUs then. + * - fast_switch_enabled is to be set by governors that support fast + * freqnency switching with the help of cpufreq_enable_fast_switch(). + */ + bool fast_switch_possible; + bool fast_switch_enabled; + /* Synchronization for frequency transitions */ bool transition_ongoing; /* Tracks transition status */ spinlock_t transition_lock; @@ -156,6 +167,7 @@ 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); +void cpufreq_enable_fast_switch(struct cpufreq_policy *policy); #else static inline unsigned int cpufreq_get(unsigned int cpu) { @@ -236,6 +248,8 @@ struct cpufreq_driver { unsigned int relation); /* Deprecated */ int (*target_index)(struct cpufreq_policy *policy, unsigned int index); + unsigned int (*fast_switch)(struct cpufreq_policy *policy, + unsigned int target_freq); /* * Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION * unset. @@ -464,6 +478,8 @@ struct cpufreq_governor { }; /* Pass a target to the cpufreq driver */ +unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq); int cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); |