PM: EM: Introduce em_compute_costs()

Move the EM costs computation code into a new dedicated function,
em_compute_costs(), that can be reused in other places in the future.

This change is not expected to alter the general functionality.
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/energy_model.c

@@ -103,14 +103,52 @@ static void em_debug_create_pd(struct device *dev) {}
 static void em_debug_remove_pd(struct device *dev) {}
 #endif
 
+static int em_compute_costs(struct device *dev, struct em_perf_state *table,
+			    struct em_data_callback *cb, int nr_states,
+			    unsigned long flags)
+{
+	unsigned long prev_cost = ULONG_MAX;
+	u64 fmax;
+	int i, ret;
+
+	/* Compute the cost of each performance state. */
+	fmax = (u64) table[nr_states - 1].frequency;
+	for (i = nr_states - 1; i >= 0; i--) {
+		unsigned long power_res, cost;
+
+		if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
+			ret = cb->get_cost(dev, table[i].frequency, &cost);
+			if (ret || !cost || cost > EM_MAX_POWER) {
+				dev_err(dev, "EM: invalid cost %lu %d\n",
+					cost, ret);
+				return -EINVAL;
+			}
+		} else {
+			power_res = table[i].power;
+			cost = div64_u64(fmax * power_res, table[i].frequency);
+		}
+
+		table[i].cost = cost;
+
+		if (table[i].cost >= prev_cost) {
+			table[i].flags = EM_PERF_STATE_INEFFICIENT;
+			dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
+				table[i].frequency);
+		} else {
+			prev_cost = table[i].cost;
+		}
+	}
+
+	return 0;
+}
+
 static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
 				int nr_states, struct em_data_callback *cb,
 				unsigned long flags)
 {
-	unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
+	unsigned long power, freq, prev_freq = 0;
 	struct em_perf_state *table;
 	int i, ret;
-	u64 fmax;
 
 	table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
 	if (!table)
@@ -154,33 +192,9 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
 		table[i].frequency = prev_freq = freq;
 	}
 
-	/* Compute the cost of each performance state. */
-	fmax = (u64) table[nr_states - 1].frequency;
-	for (i = nr_states - 1; i >= 0; i--) {
-		unsigned long power_res, cost;
-
-		if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
-			ret = cb->get_cost(dev, table[i].frequency, &cost);
-			if (ret || !cost || cost > EM_MAX_POWER) {
-				dev_err(dev, "EM: invalid cost %lu %d\n",
-					cost, ret);
-				goto free_ps_table;
-			}
-		} else {
-			power_res = table[i].power;
-			cost = div64_u64(fmax * power_res, table[i].frequency);
-		}
-
-		table[i].cost = cost;
-
-		if (table[i].cost >= prev_cost) {
-			table[i].flags = EM_PERF_STATE_INEFFICIENT;
-			dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
-				table[i].frequency);
-		} else {
-			prev_cost = table[i].cost;
-		}
-	}
+	ret = em_compute_costs(dev, table, cb, nr_states, flags);
+	if (ret)
+		goto free_ps_table;
 
 	pd->table = table;
 	pd->nr_perf_states = nr_states;