PM: Do not use the syscore flag for runtime PM

The syscore device PM flag used to mark the devices (belonging to
PM domains) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages, need not be
accessed by the runtime PM core functions, because all of the devices
it is set for need to be marked as "irq safe" anyway and are
protected from being turned off by runtime PM by ensuring that their
usage counters are always set.

For this reason, make the syscore flag system-wide PM-specific
and simplify the code used for manipulating it, because it need not
acquire the device's power.lock any more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/base/power/common.c

@@ -83,18 +83,3 @@ int dev_pm_put_subsys_data(struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
-
-/**
- * dev_pm_syscore_device - Set/unset the given device's power.syscore flag.
- * @dev: Device whose flag is to be modified.
- * @val: New value of the flag.
- */
-void dev_pm_syscore_device(struct device *dev, bool val)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->power.lock, flags);
-	dev->power.syscore = val;
-	spin_unlock_irqrestore(&dev->power.lock, flags);
-}
-EXPORT_SYMBOL_GPL(dev_pm_syscore_device);

drivers/base/power/domain.c

@@ -442,7 +442,7 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
 	not_suspended = 0;
 	list_for_each_entry(pdd, &genpd->dev_list, list_node)
 		if (pdd->dev->driver && (!pm_runtime_suspended(pdd->dev)
-		    || pdd->dev->power.irq_safe || pdd->dev->power.syscore))
+		    || pdd->dev->power.irq_safe))
 			not_suspended++;
 
 	if (not_suspended > genpd->in_progress)

drivers/base/power/runtime.c

@@ -134,7 +134,7 @@ static int rpm_check_suspend_allowed(struct device *dev)
 
 	if (dev->power.runtime_error)
 		retval = -EINVAL;
-	else if (dev->power.disable_depth > 0 || dev->power.syscore)
+	else if (dev->power.disable_depth > 0)
 		retval = -EACCES;
 	else if (atomic_read(&dev->power.usage_count) > 0)
 		retval = -EAGAIN;

include/linux/device.h

@@ -772,6 +772,13 @@ static inline void pm_suspend_ignore_children(struct device *dev, bool enable)
 	dev->power.ignore_children = enable;
 }
 
+static inline void dev_pm_syscore_device(struct device *dev, bool val)
+{
+#ifdef CONFIG_PM_SLEEP
+	dev->power.syscore = val;
+#endif
+}
+
 static inline void device_lock(struct device *dev)
 {
 	mutex_lock(&dev->mutex);

include/linux/pm.h

@@ -43,12 +43,8 @@ struct device;
 
 #ifdef CONFIG_PM
 extern const char power_group_name[];		/* = "power" */
-
-extern void dev_pm_syscore_device(struct device *dev, bool val);
 #else
 #define power_group_name	NULL
-
-static inline void dev_pm_syscore_device(struct device *dev, bool val) {}
 #endif
 
 typedef struct pm_message {
@@ -515,13 +511,13 @@ struct dev_pm_info {
 	bool			is_suspended:1;	/* Ditto */
 	bool			ignore_children:1;
 	bool			early_init:1;	/* Owned by the PM core */
-	bool			syscore:1;
 	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;
 	struct completion	completion;
 	struct wakeup_source	*wakeup;
 	bool			wakeup_path:1;
+	bool			syscore:1;
 #else
 	unsigned int		should_wakeup:1;
 #endif