cpuidle: Allow enforcing deepest idle state selection

When idle injection is used to cap power, we need to override the
governor's choice of idle states.

For this reason, make it possible the deepest idle state selection to
be enforced by setting a flag on a given CPU to achieve the maximum
potential power draw reduction.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 15deea449edc..da346f2817a8 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -74,6 +74,7 @@ struct cpuidle_driver_kobj;
 struct cpuidle_device {
         unsigned int            registered:1;
         unsigned int            enabled:1;
+        unsigned int            use_deepest_state:1;
         unsigned int            cpu;
 
         int                     last_residency;
@@ -192,11 +193,12 @@ static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 #endif
 
-#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_SUSPEND)
+#ifdef CONFIG_CPU_IDLE
 extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
                                       struct cpuidle_device *dev);
 extern int cpuidle_enter_freeze(struct cpuidle_driver *drv,
                                 struct cpuidle_device *dev);
+extern void cpuidle_use_deepest_state(bool enable);
 #else
 static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
                                              struct cpuidle_device *dev)
@@ -204,6 +206,9 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
 static inline int cpuidle_enter_freeze(struct cpuidle_driver *drv,
                                        struct cpuidle_device *dev)
 {return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable)
+{
+}
 #endif
 
 /* kernel/sched/idle.c */