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authorSteve Muckle <steve.muckle@linaro.org>2016-07-13 13:25:25 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-07-21 14:46:08 +0200
commite3c06236087051d5c62d60d0668588c370fda887 (patch)
tree87bf8e5a9b77cb24d416851136451aaf43f27fd1 /drivers/cpufreq
parentda7de91c3e237f3ace1aa29b82c69702dc0176c5 (diff)
downloadblackbird-op-linux-e3c06236087051d5c62d60d0668588c370fda887.tar.gz
blackbird-op-linux-e3c06236087051d5c62d60d0668588c370fda887.zip
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 <rafael.j.wysocki@intel.com> Signed-off-by: Steve Muckle <smuckle@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 118b4f30a406..b696baeb249d 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -492,6 +492,29 @@ void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
}
EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
+/**
+ * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
+ * one.
+ * @target_freq: target frequency to resolve.
+ *
+ * The target to driver frequency mapping is cached in the policy.
+ *
+ * Return: Lowest driver-supported frequency greater than or equal to the
+ * given target_freq, subject to policy (min/max) and driver limitations.
+ */
+unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
+ unsigned int target_freq)
+{
+ target_freq = clamp_val(target_freq, policy->min, policy->max);
+ policy->cached_target_freq = target_freq;
+ if (cpufreq_driver->resolve_freq)
+ return cpufreq_driver->resolve_freq(policy, target_freq);
+ policy->cached_resolved_idx =
+ cpufreq_frequency_table_target(policy, target_freq,
+ CPUFREQ_RELATION_L);
+ return policy->freq_table[policy->cached_resolved_idx].frequency;
+}
+
/*********************************************************************
* SYSFS INTERFACE *
*********************************************************************/
@@ -2199,6 +2222,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
policy->min = new_policy->min;
policy->max = new_policy->max;
+ policy->cached_target_freq = UINT_MAX;
+
pr_debug("new min and max freqs are %u - %u kHz\n",
policy->min, policy->max);
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