cpufreq: Add of_perf_domain_get_sharing_cpumask

Add of_perf_domain_get_sharing_cpumask function to group cpu
to specific performance domain.
Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
[ Viresh: create separate routine parse_perf_domain() and always set the
	  cpumask. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

include/linux/cpufreq.h

@@ -14,6 +14,8 @@
 #include <linux/completion.h>
 #include <linux/kobject.h>
 #include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/pm_opp.h>
 #include <linux/pm_qos.h>
 #include <linux/spinlock.h>
@@ -1003,6 +1005,55 @@ static inline int cpufreq_table_count_valid_entries(const struct cpufreq_policy
 
 	return count;
 }
+
+static inline int parse_perf_domain(int cpu, const char *list_name,
+				    const char *cell_name)
+{
+	struct device_node *cpu_np;
+	struct of_phandle_args args;
+	int ret;
+
+	cpu_np = of_cpu_device_node_get(cpu);
+	if (!cpu_np)
+		return -ENODEV;
+
+	ret = of_parse_phandle_with_args(cpu_np, list_name, cell_name, 0,
+					 &args);
+	if (ret < 0)
+		return ret;
+
+	of_node_put(cpu_np);
+
+	return args.args[0];
+}
+
+static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_name,
+						     const char *cell_name, struct cpumask *cpumask)
+{
+	int target_idx;
+	int cpu, ret;
+
+	ret = parse_perf_domain(pcpu, list_name, cell_name);
+	if (ret < 0)
+		return ret;
+
+	target_idx = ret;
+	cpumask_set_cpu(pcpu, cpumask);
+
+	for_each_possible_cpu(cpu) {
+		if (cpu == pcpu)
+			continue;
+
+		ret = parse_perf_domain(pcpu, list_name, cell_name);
+		if (ret < 0)
+			continue;
+
+		if (target_idx == ret)
+			cpumask_set_cpu(cpu, cpumask);
+	}
+
+	return target_idx;
+}
 #else
 static inline int cpufreq_boost_trigger_state(int state)
 {
@@ -1022,6 +1073,12 @@ static inline bool policy_has_boost_freq(struct cpufreq_policy *policy)
 {
 	return false;
 }
+
+static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_name,
+						     const char *cell_name, struct cpumask *cpumask)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
@@ -1043,7 +1100,6 @@ void arch_set_freq_scale(const struct cpumask *cpus,
 {
 }
 #endif
-
 /* the following are really really optional */
 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 extern struct freq_attr cpufreq_freq_attr_scaling_boost_freqs;