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().
The above API will call a new cpufreq driver callback, resolve_freq(),
if it has been registered by the driver. If that callback has not been
registered and a frequency table is available then the frequency table
is walked using cpufreq_frequency_table_target().
UINT_MAX is returned if no driver callback or frequency table is
available.
Suggested-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Signed-off-by: Steve Muckle <smuc...@linaro.org>
---
drivers/cpufreq/cpufreq.c | 25 +++++++++++++++++++++++++
include/linux/cpufreq.h | 11 +++++++++++
2 files changed, 36 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 77d77a4e3b74..3b44f4bdc071 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1849,6 +1849,31 @@ unsigned int cpufreq_driver_fast_switch(struct
cpufreq_policy *policy,
}
EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
+unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
+ unsigned int target_freq)
+{
+ struct cpufreq_frequency_table *freq_table;
+ int index, retval;
+
+ clamp_val(target_freq, policy->min, policy->max);
+
+ if (cpufreq_driver->resolve_freq)
+ return cpufreq_driver->resolve_freq(policy, target_freq);
+
+ freq_table = cpufreq_frequency_get_table(policy->cpu);
+ if (!freq_table)
+ return UINT_MAX;
+
+ retval = cpufreq_frequency_table_target(policy, freq_table,
+ target_freq, CPUFREQ_RELATION_L,
+ &index);
+ if (retval)
+ return UINT_MAX;
+
+ return freq_table[index].frequency;
+}
+EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
+
/* Must set freqs->new to intermediate frequency */
static int __target_intermediate(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int index)
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 4e81e08db752..675f17f98e75 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -271,6 +271,13 @@ struct cpufreq_driver {
int (*target_intermediate)(struct cpufreq_policy *policy,
unsigned int index);
+ /*
+ * Return the driver-supported frequency that a particular target
+ * frequency maps to (does not set the new frequency).
+ */
+ unsigned int (*resolve_freq)(struct cpufreq_policy *policy,
+ unsigned int target_freq);
+
/* should be defined, if possible */
unsigned int (*get)(unsigned int cpu);
@@ -487,6 +494,10 @@ 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);
--
2.4.10
