cpuidle: introduce CPU_PM_CPU_IDLE_ENTER macro for ARM{32, 64}

The function arm_enter_idle_state is exactly the same in both generic
ARM{32,64} CPUIdle driver and will be the same even on ARM64 backend
for ACPI processor idle driver. So we can unify it and move it to a
common place by introducing CPU_PM_CPU_IDLE_ENTER macro that can be
used in all places avoiding duplication.

This is in preparation of reuse of the generic cpuidle entry function
for ACPI LPI support on ARM64.

Suggested-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/cpuidle-arm.c

@@ -36,26 +36,12 @@
 static int arm_enter_idle_state(struct cpuidle_device *dev,
 				struct cpuidle_driver *drv, int idx)
 {
-	int ret;
-
-	if (!idx) {
-		cpu_do_idle();
-		return idx;
-	}
-
-	ret = cpu_pm_enter();
-	if (!ret) {
 	/*
-		 * Pass idle state index to cpu_suspend which in turn will
+	 * Pass idle state index to arm_cpuidle_suspend which in turn
-		 * call the CPU ops suspend protocol with idle index as a
+	 * will call the CPU ops suspend protocol with idle index as a
 	 * parameter.
 	 */
-		ret = arm_cpuidle_suspend(idx);
+	return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx);
-
-		cpu_pm_exit();
-	}
-
-	return ret ? -1 : idx;
 }
 
 static struct cpuidle_driver arm_idle_driver = {

include/linux/cpuidle.h

@@ -252,4 +252,22 @@ static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 #define CPUIDLE_DRIVER_STATE_START	0
 #endif
 
+#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)	\
+({								\
+	int __ret;						\
+								\
+	if (!idx) {						\
+		cpu_do_idle();					\
+		return idx;					\
+	}							\
+								\
+	__ret = cpu_pm_enter();					\
+	if (!__ret) {						\
+		__ret = low_level_idle_enter(idx);		\
+		cpu_pm_exit();					\
+	}							\
+								\
+	__ret ? -1 : idx;					\
+})
+
 #endif /* _LINUX_CPUIDLE_H */