From e3c06236087051d5c62d60d0668588c370fda887 Mon Sep 17 00:00:00 2001 From: Steve Muckle Date: Wed, 13 Jul 2016 13:25:25 -0700 Subject: cpufreq: add cpufreq_driver_resolve_freq() Cpufreq governors may need to know what a particular target frequency maps to in the driver without necessarily wanting to set the frequency. Support this operation via a new cpufreq API, cpufreq_driver_resolve_freq(). This API returns the lowest driver frequency equal or greater than the target frequency (CPUFREQ_RELATION_L), subject to any policy (min/max) or driver limitations. The mapping is also cached in the policy so that a subsequent fast_switch operation can avoid repeating the same lookup. The API will call a new cpufreq driver callback, resolve_freq(), if it has been registered by the driver. Otherwise the frequency is resolved via cpufreq_frequency_table_target(). Rather than require ->target() style drivers to provide a resolve_freq() callback it is left to the caller to ensure that the driver implements this callback if necessary to use cpufreq_driver_resolve_freq(). Suggested-by: Rafael J. Wysocki Signed-off-by: Steve Muckle Signed-off-by: Rafael J. Wysocki --- include/linux/cpufreq.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/cpufreq.h') diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index c6410b1b2490..631ba33bbe9f 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -120,6 +120,10 @@ struct cpufreq_policy { bool fast_switch_possible; bool fast_switch_enabled; + /* Cached frequency lookup from cpufreq_driver_resolve_freq. */ + unsigned int cached_target_freq; + int cached_resolved_idx; + /* Synchronization for frequency transitions */ bool transition_ongoing; /* Tracks transition status */ spinlock_t transition_lock; @@ -270,6 +274,16 @@ struct cpufreq_driver { unsigned int index); unsigned int (*fast_switch)(struct cpufreq_policy *policy, unsigned int target_freq); + + /* + * Caches and returns the lowest driver-supported frequency greater than + * or equal to the target frequency, subject to any driver limitations. + * Does not set the frequency. Only to be implemented for drivers with + * target(). + */ + unsigned int (*resolve_freq)(struct cpufreq_policy *policy, + unsigned int target_freq); + /* * Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION * unset. @@ -501,6 +515,8 @@ int cpufreq_driver_target(struct cpufreq_policy *policy, int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); +unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, + unsigned int target_freq); int cpufreq_register_governor(struct cpufreq_governor *governor); void cpufreq_unregister_governor(struct cpufreq_governor *governor); -- cgit