PM / Domains: Move syscore flag from subsys data to struct device

The syscore device PM flag is used to mark the devices (belonging to
a PM domain) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages.  That flag is
stored in the device's struct pm_subsys_data object whose address is
available from struct device.  However, in some situations it may be
convenient to set that flag before the device is added to a PM
domain, so it is better to move it directly to the "power" member of
struct device.  Then, it can be checked by the routines in
drivers/base/power/runtime.c and drivers/base/power/main.c, which is
more straightforward.

This also reduces the number of dev_gpd_data() invocations in the
generic PM domains framework, so the overhead related to the syscore
flag is slightly smaller.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>

include/linux/pm.h

@@ -43,8 +43,12 @@ 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 {
@@ -511,6 +515,7 @@ 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;