cpufreq: Disallow ->resolve_freq() for drivers providing ->target_index()

The handlers provided by cpufreq core are sufficient for resolving the
frequency for drivers providing ->target_index(), as the core already
has the frequency table and so ->resolve_freq() isn't required for such
platforms.

This patch disallows drivers with ->target_index() callback to use the
->resolve_freq() callback.

Also, it fixes a potential kernel crash for drivers providing ->target()
but no ->resolve_freq().

Fixes: e3c062360870 "cpufreq: add cpufreq_driver_resolve_freq()"
Signed-off-by: Viresh Kumar <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/cpufreq.c

···
 {
 	target_freq = clamp_val(target_freq, policy->min, policy->max);
 	policy->cached_target_freq = target_freq;
+
+	if (cpufreq_driver->target_index) {
+		int idx;
+
+		idx = cpufreq_frequency_table_target(policy, target_freq,
+						     CPUFREQ_RELATION_L);
+		policy->cached_resolved_idx = idx;
+		return policy->freq_table[idx].frequency;
+	}
+
 	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;
+
+	return target_freq;
 }
 
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