cpuidle:powernv: Add helper function to populate powernv idle states.

In the current code for powernv_add_idle_states, there is a lot of code
duplication while initializing an idle state in powernv_states table.

Add an inline helper function to populate the powernv_states[] table
for a given idle state. Invoke this for populating the "Nap",
"Fastsleep" and the stop states in powernv_add_idle_states.

Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/cpuidle/cpuidle-powernv.c

@@ -20,6 +20,10 @@
 #include <asm/opal.h>
 #include <asm/runlatch.h>
 
+/*
+ * Expose only those Hardware idle states via the cpuidle framework
+ * that have latency value below POWERNV_THRESHOLD_LATENCY_NS.
+ */
 #define POWERNV_THRESHOLD_LATENCY_NS 200000
 
 static struct cpuidle_driver powernv_idle_driver = {
@@ -167,6 +171,24 @@ static int powernv_cpuidle_driver_init(void)
 	return 0;
 }
 
+static inline void add_powernv_state(int index, const char *name,
+				     unsigned int flags,
+				     int (*idle_fn)(struct cpuidle_device *,
+						    struct cpuidle_driver *,
+						    int),
+				     unsigned int target_residency,
+				     unsigned int exit_latency,
+				     u64 psscr_val)
+{
+	strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);
+	strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN);
+	powernv_states[index].flags = flags;
+	powernv_states[index].target_residency = target_residency;
+	powernv_states[index].exit_latency = exit_latency;
+	powernv_states[index].enter = idle_fn;
+	stop_psscr_table[index] = psscr_val;
+}
+
 static int powernv_add_idle_states(void)
 {
 	struct device_node *power_mgt;
@@ -236,6 +258,7 @@ static int powernv_add_idle_states(void)
 		"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
 
 	for (i = 0; i < dt_idle_states; i++) {
+		unsigned int exit_latency, target_residency;
 		/*
 		 * If an idle state has exit latency beyond
 		 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
@@ -243,28 +266,33 @@ static int powernv_add_idle_states(void)
 		 */
 		if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
 			continue;
+		/*
+		 * Firmware passes residency and latency values in ns.
+		 * cpuidle expects it in us.
+		 */
+		exit_latency = latency_ns[i] / 1000;
+		if (!rc)
+			target_residency = residency_ns[i] / 1000;
+		else
+			target_residency = 0;
 
 		/*
-		 * Cpuidle accepts exit_latency and target_residency in us.
-		 * Use default target_residency values if f/w does not expose it.
+		 * For nap and fastsleep, use default target_residency
+		 * values if f/w does not expose it.
 		 */
 		if (flags[i] & OPAL_PM_NAP_ENABLED) {
+			if (!rc)
+				target_residency = 100;
 			/* Add NAP state */
-			strcpy(powernv_states[nr_idle_states].name, "Nap");
-			strcpy(powernv_states[nr_idle_states].desc, "Nap");
-			powernv_states[nr_idle_states].flags = 0;
-			powernv_states[nr_idle_states].target_residency = 100;
-			powernv_states[nr_idle_states].enter = nap_loop;
+			add_powernv_state(nr_idle_states, "Nap",
+					  CPUIDLE_FLAG_NONE, nap_loop,
+					  target_residency, exit_latency, 0);
 		} else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
 				!(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
-			strncpy(powernv_states[nr_idle_states].name,
-				names[i], CPUIDLE_NAME_LEN);
-			strncpy(powernv_states[nr_idle_states].desc,
-				names[i], CPUIDLE_NAME_LEN);
-			powernv_states[nr_idle_states].flags = 0;
-
-			powernv_states[nr_idle_states].enter = stop_loop;
-			stop_psscr_table[nr_idle_states] = psscr_val[i];
+			add_powernv_state(nr_idle_states, names[i],
+					  CPUIDLE_FLAG_NONE, stop_loop,
+					  target_residency, exit_latency,
+					  psscr_val[i]);
 		}
 
 		/*
@@ -274,32 +302,21 @@ static int powernv_add_idle_states(void)
 #ifdef CONFIG_TICK_ONESHOT
 		if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
 			flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
+			if (!rc)
+				target_residency = 300000;
 			/* Add FASTSLEEP state */
-			strcpy(powernv_states[nr_idle_states].name, "FastSleep");
-			strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
-			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
-			powernv_states[nr_idle_states].target_residency = 300000;
-			powernv_states[nr_idle_states].enter = fastsleep_loop;
+			add_powernv_state(nr_idle_states, "FastSleep",
+					  CPUIDLE_FLAG_TIMER_STOP,
+					  fastsleep_loop,
+					  target_residency, exit_latency, 0);
 		} else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
 				(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
-			strncpy(powernv_states[nr_idle_states].name,
-				names[i], CPUIDLE_NAME_LEN);
-			strncpy(powernv_states[nr_idle_states].desc,
-				names[i], CPUIDLE_NAME_LEN);
-
-			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
-			powernv_states[nr_idle_states].enter = stop_loop;
-			stop_psscr_table[nr_idle_states] = psscr_val[i];
+			add_powernv_state(nr_idle_states, names[i],
+					  CPUIDLE_FLAG_TIMER_STOP, stop_loop,
+					  target_residency, exit_latency,
+					  psscr_val[i]);
 		}
 #endif
-		powernv_states[nr_idle_states].exit_latency =
-				((unsigned int)latency_ns[i]) / 1000;
-
-		if (!rc) {
-			powernv_states[nr_idle_states].target_residency =
-				((unsigned int)residency_ns[i]) / 1000;
-		}
-
 		nr_idle_states++;
 	}
 out:

include/linux/cpuidle.h

@@ -62,6 +62,7 @@ struct cpuidle_state {
 };
 
 /* Idle State Flags */
+#define CPUIDLE_FLAG_NONE       (0x00)
 #define CPUIDLE_FLAG_COUPLED	(0x02) /* state applies to multiple cpus */
 #define CPUIDLE_FLAG_TIMER_STOP (0x04)  /* timer is stopped on this state */