summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--drivers/cpuidle/cpuidle.c49
-rw-r--r--include/linux/cpuidle.h4
-rw-r--r--include/linux/suspend.h16
-rw-r--r--kernel/power/suspend.c43
-rw-r--r--kernel/sched/idle.c16
5 files changed, 96 insertions, 32 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 125150d..23a8d6c 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -19,6 +19,7 @@
#include <linux/ktime.h>
#include <linux/hrtimer.h>
#include <linux/module.h>
+#include <linux/suspend.h>
#include <trace/events/power.h>
#include "cpuidle.h"
@@ -32,7 +33,6 @@ LIST_HEAD(cpuidle_detected_devices);
static int enabled_devices;
static int off __read_mostly;
static int initialized __read_mostly;
-static bool use_deepest_state __read_mostly;
int cpuidle_disabled(void)
{
@@ -66,24 +66,9 @@ int cpuidle_play_dead(void)
}
/**
- * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode.
- * @enable: Whether enable or disable the feature.
- *
- * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
- * always use the state with the greatest exit latency (out of the states that
- * are not disabled).
- *
- * This function can only be called after cpuidle_pause() to avoid races.
- */
-void cpuidle_use_deepest_state(bool enable)
-{
- use_deepest_state = enable;
-}
-
-/**
- * cpuidle_find_deepest_state - Find the state of the greatest exit latency.
- * @drv: cpuidle driver for a given CPU.
- * @dev: cpuidle device for a given CPU.
+ * cpuidle_find_deepest_state - Find deepest state meeting specific conditions.
+ * @drv: cpuidle driver for the given CPU.
+ * @dev: cpuidle device for the given CPU.
*/
static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
@@ -105,6 +90,27 @@ static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
}
/**
+ * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle.
+ *
+ * Find the deepest state available and enter it.
+ */
+void cpuidle_enter_freeze(void)
+{
+ struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+ int index;
+
+ index = cpuidle_find_deepest_state(drv, dev);
+ if (index >= 0)
+ cpuidle_enter(drv, dev, index);
+ else
+ arch_cpu_idle();
+
+ /* Interrupts are enabled again here. */
+ local_irq_disable();
+}
+
+/**
* cpuidle_enter_state - enter the state and update stats
* @dev: cpuidle device for this cpu
* @drv: cpuidle driver for this cpu
@@ -166,9 +172,6 @@ int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
if (!drv || !dev || !dev->enabled)
return -EBUSY;
- if (unlikely(use_deepest_state))
- return cpuidle_find_deepest_state(drv, dev);
-
return cpuidle_curr_governor->select(drv, dev);
}
@@ -200,7 +203,7 @@ int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
*/
void cpuidle_reflect(struct cpuidle_device *dev, int index)
{
- if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
+ if (cpuidle_curr_governor->reflect)
cpuidle_curr_governor->reflect(dev, index);
}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index ab70f3b..f63aabf 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -141,7 +141,7 @@ extern void cpuidle_resume(void);
extern int cpuidle_enable_device(struct cpuidle_device *dev);
extern void cpuidle_disable_device(struct cpuidle_device *dev);
extern int cpuidle_play_dead(void);
-extern void cpuidle_use_deepest_state(bool enable);
+extern void cpuidle_enter_freeze(void);
extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
#else
@@ -174,7 +174,7 @@ static inline int cpuidle_enable_device(struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
static inline int cpuidle_play_dead(void) {return -ENODEV; }
-static inline void cpuidle_use_deepest_state(bool enable) {}
+static inline void cpuidle_enter_freeze(void) { }
static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
struct cpuidle_device *dev) {return NULL; }
#endif
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 3388c1b..5efe743 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -201,6 +201,21 @@ struct platform_freeze_ops {
*/
extern void suspend_set_ops(const struct platform_suspend_ops *ops);
extern int suspend_valid_only_mem(suspend_state_t state);
+
+/* Suspend-to-idle state machnine. */
+enum freeze_state {
+ FREEZE_STATE_NONE, /* Not suspended/suspending. */
+ FREEZE_STATE_ENTER, /* Enter suspend-to-idle. */
+ FREEZE_STATE_WAKE, /* Wake up from suspend-to-idle. */
+};
+
+extern enum freeze_state __read_mostly suspend_freeze_state;
+
+static inline bool idle_should_freeze(void)
+{
+ return unlikely(suspend_freeze_state == FREEZE_STATE_ENTER);
+}
+
extern void freeze_set_ops(const struct platform_freeze_ops *ops);
extern void freeze_wake(void);
@@ -228,6 +243,7 @@ extern int pm_suspend(suspend_state_t state);
static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
+static inline bool idle_should_freeze(void) { return false; }
static inline void freeze_set_ops(const struct platform_freeze_ops *ops) {}
static inline void freeze_wake(void) {}
#endif /* !CONFIG_SUSPEND */
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index c347e3c..b7d6b3a 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -37,7 +37,9 @@ const char *pm_states[PM_SUSPEND_MAX];
static const struct platform_suspend_ops *suspend_ops;
static const struct platform_freeze_ops *freeze_ops;
static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
-static bool suspend_freeze_wake;
+
+enum freeze_state __read_mostly suspend_freeze_state;
+static DEFINE_SPINLOCK(suspend_freeze_lock);
void freeze_set_ops(const struct platform_freeze_ops *ops)
{
@@ -48,22 +50,49 @@ void freeze_set_ops(const struct platform_freeze_ops *ops)
static void freeze_begin(void)
{
- suspend_freeze_wake = false;
+ suspend_freeze_state = FREEZE_STATE_NONE;
}
static void freeze_enter(void)
{
- cpuidle_use_deepest_state(true);
+ spin_lock_irq(&suspend_freeze_lock);
+ if (pm_wakeup_pending())
+ goto out;
+
+ suspend_freeze_state = FREEZE_STATE_ENTER;
+ spin_unlock_irq(&suspend_freeze_lock);
+
+ get_online_cpus();
cpuidle_resume();
- wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
+
+ /* Push all the CPUs into the idle loop. */
+ wake_up_all_idle_cpus();
+ pr_debug("PM: suspend-to-idle\n");
+ /* Make the current CPU wait so it can enter the idle loop too. */
+ wait_event(suspend_freeze_wait_head,
+ suspend_freeze_state == FREEZE_STATE_WAKE);
+ pr_debug("PM: resume from suspend-to-idle\n");
+
cpuidle_pause();
- cpuidle_use_deepest_state(false);
+ put_online_cpus();
+
+ spin_lock_irq(&suspend_freeze_lock);
+
+ out:
+ suspend_freeze_state = FREEZE_STATE_NONE;
+ spin_unlock_irq(&suspend_freeze_lock);
}
void freeze_wake(void)
{
- suspend_freeze_wake = true;
- wake_up(&suspend_freeze_wait_head);
+ unsigned long flags;
+
+ spin_lock_irqsave(&suspend_freeze_lock, flags);
+ if (suspend_freeze_state > FREEZE_STATE_NONE) {
+ suspend_freeze_state = FREEZE_STATE_WAKE;
+ wake_up(&suspend_freeze_wait_head);
+ }
+ spin_unlock_irqrestore(&suspend_freeze_lock, flags);
}
EXPORT_SYMBOL_GPL(freeze_wake);
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index aaf1c1d..94b2d7b 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -7,6 +7,7 @@
#include <linux/tick.h>
#include <linux/mm.h>
#include <linux/stackprotector.h>
+#include <linux/suspend.h>
#include <asm/tlb.h>
@@ -105,6 +106,21 @@ static void cpuidle_idle_call(void)
rcu_idle_enter();
/*
+ * Suspend-to-idle ("freeze") is a system state in which all user space
+ * has been frozen, all I/O devices have been suspended and the only
+ * activity happens here and in iterrupts (if any). In that case bypass
+ * the cpuidle governor and go stratight for the deepest idle state
+ * available. Possibly also suspend the local tick and the entire
+ * timekeeping to prevent timer interrupts from kicking us out of idle
+ * until a proper wakeup interrupt happens.
+ */
+ if (idle_should_freeze()) {
+ cpuidle_enter_freeze();
+ local_irq_enable();
+ goto exit_idle;
+ }
+
+ /*
* Ask the cpuidle framework to choose a convenient idle state.
* Fall back to the default arch idle method on errors.
*/
OpenPOWER on IntegriCloud