diff options
| author | Michael Turquette <mturquette@baylibre.com> | 2015-07-07 19:24:20 +0100 |
|---|---|---|
| committer | Vincent Guittot <vincent.guittot@linaro.org> | 2015-07-27 17:59:42 +0200 |
| commit | 6d23318179e499ed88ffca8c021212198347897d (patch) | |
| tree | 30f7dec504639b93093f8e3a93fd28e2c73f2b32 /include | |
| parent | 0a5999b31a8b86cf507b15046ca8d4a4343ada53 (diff) | |
cpufreq: introduce cpufreq_driver_might_sleep
Some architectures and platforms perform CPU frequency transitions
through a non-blocking method, while some might block or sleep. This
distinction is important when trying to change frequency from interrupt
context or in any other non-interruptable context, such as from the
Linux scheduler.
Describe this distinction with a cpufreq driver flag,
CPUFREQ_DRIVER_WILL_NOT_SLEEP. The default is to not have this flag set,
thus erring on the side of caution.
cpufreq_driver_might_sleep() is also introduced in this patch. Setting
the above flag will allow this function to return false.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/cpufreq.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 29ad97c34fd5..8219656ced25 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -160,6 +160,7 @@ 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); +bool cpufreq_driver_might_sleep(void); struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy); #else static inline unsigned int cpufreq_get(unsigned int cpu) @@ -317,6 +318,14 @@ struct cpufreq_driver { */ #define CPUFREQ_NEED_INITIAL_FREQ_CHECK (1 << 5) +/* + * Set by drivers that will never block or sleep during their frequency + * transition. Used to indicate when it is safe to call cpufreq_driver_target + * from non-interruptable context. Drivers must opt-in to this flag, as the + * safe default is that they might sleep. + */ +#define CPUFREQ_DRIVER_WILL_NOT_SLEEP (1 << 6) + int cpufreq_register_driver(struct cpufreq_driver *driver_data); int cpufreq_unregister_driver(struct cpufreq_driver *driver_data); |