cpufreq: Restrict enabling boost on policies with no boost frequencies

It is possible to have a scenario where not all cpufreq policies support
boost frequencies. And letting sysfs (or other parts of the kernel)
enable boost feature for that policy isn't correct.

Now that all drivers (that required a change) are updated to set the
policy->boost_supported properly, check this flag before enabling boost
feature for a policy.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: vireshk

drivers/cpufreq/cpufreq.c

@@ -632,6 +632,9 @@ static ssize_t store_local_boost(struct cpufreq_policy *policy,
 	if (!cpufreq_driver->boost_enabled)
 		return -EINVAL;
 
+	if (!policy->boost_supported)
+		return -EINVAL;
+
 	if (policy->boost_enabled == enable)
 		return count;
 
@@ -1587,7 +1590,7 @@ static int cpufreq_online(unsigned int cpu)
 		policy->cdev = of_cpufreq_cooling_register(policy);
 
 	/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
-	if (cpufreq_driver->set_boost &&
+	if (cpufreq_driver->set_boost && policy->boost_supported &&
 	    policy->boost_enabled != cpufreq_boost_enabled()) {
 		policy->boost_enabled = cpufreq_boost_enabled();
 		ret = cpufreq_driver->set_boost(policy, policy->boost_enabled);
@@ -2824,6 +2827,9 @@ static int cpufreq_boost_trigger_state(int state)
 
 	cpus_read_lock();
 	for_each_active_policy(policy) {
+		if (!policy->boost_supported)
+			continue;
+
 		policy->boost_enabled = state;
 		ret = cpufreq_driver->set_boost(policy, state);
 		if (ret) {