pm: policy: Selectively compile on "zephyr,power-state" compatible

Coverity is complaining:

      CID 316017:  Control flow issues  (NO_EFFECT)
  >>> This less-than-zero comparison of an unsigned value is never true.
  148      for (size_t i = 0; i < ARRAY_SIZE(substate_lock_t); i++) {

This is a false positive but we can still optimize the code and making
coverity happy by simply avoiding compiling the offending code when no
power states are defined into the DT.

Signed-off-by: Carlo Caione <[email protected]>

Author: carlocaione

subsys/pm/policy.c

@@ -15,6 +15,8 @@
 #include <zephyr/sys/atomic.h>
 #include <zephyr/toolchain.h>
 
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
+
 #define DT_SUB_LOCK_INIT(node_id)				\
 	{ .state = PM_STATE_DT_INIT(node_id),			\
 	  .substate_id = DT_PROP_OR(node_id, substate_id, 0),	\
@@ -40,6 +42,8 @@ static struct {
 	DT_FOREACH_STATUS_OKAY(zephyr_power_state, DT_SUB_LOCK_INIT)
 };
 
+#endif
+
 /** Lock to synchronize access to the latency request list. */
 static struct k_spinlock latency_lock;
 /** List of maximum latency requests. */
@@ -189,17 +193,20 @@ const struct pm_state_info *pm_policy_next_state(uint8_t cpu, int32_t ticks)
 
 void pm_policy_state_lock_get(enum pm_state state, uint8_t substate_id)
 {
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 	for (size_t i = 0; i < ARRAY_SIZE(substate_lock_t); i++) {
 		if (substate_lock_t[i].state == state &&
 		   (substate_lock_t[i].substate_id == substate_id ||
 		    substate_id == PM_ALL_SUBSTATES)) {
 			atomic_inc(&substate_lock_t[i].lock);
 		}
 	}
+#endif
 }
 
 void pm_policy_state_lock_put(enum pm_state state, uint8_t substate_id)
 {
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 	for (size_t i = 0; i < ARRAY_SIZE(substate_lock_t); i++) {
 		if (substate_lock_t[i].state == state &&
 		   (substate_lock_t[i].substate_id == substate_id ||
@@ -211,17 +218,20 @@ void pm_policy_state_lock_put(enum pm_state state, uint8_t substate_id)
 			__ASSERT(cnt >= 1, "Unbalanced state lock get/put");
 		}
 	}
+#endif
 }
 
 bool pm_policy_state_lock_is_active(enum pm_state state, uint8_t substate_id)
 {
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 	for (size_t i = 0; i < ARRAY_SIZE(substate_lock_t); i++) {
 		if (substate_lock_t[i].state == state &&
 		   (substate_lock_t[i].substate_id == substate_id ||
 		    substate_id == PM_ALL_SUBSTATES)) {
 			return (atomic_get(&substate_lock_t[i].lock) != 0);
 		}
 	}
+#endif
 
 	return false;
 }