PM: hibernate: Add pm_hibernation_mode_is_suspend()

Some drivers have different flows for hibernation and suspend. If
the driver opportunistically will skip thaw() then it needs a hint
to know what is happening after the hibernate.

Introduce a new symbol pm_hibernation_mode_is_suspend() that drivers
can call to determine if suspending the system for this purpose.

Tested-by: Ionut Nechita <ionut_n2001@yahoo.com>
Tested-by: Kenneth Crudup <kenny@panix.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: superm1

include/linux/suspend.h

@@ -276,6 +276,7 @@ extern void arch_suspend_enable_irqs(void);
 
 extern int pm_suspend(suspend_state_t state);
 extern bool sync_on_suspend_enabled;
+bool pm_hibernation_mode_is_suspend(void);
 #else /* !CONFIG_SUSPEND */
 #define suspend_valid_only_mem	NULL
 
@@ -288,6 +289,7 @@ static inline bool pm_suspend_via_firmware(void) { return false; }
 static inline bool pm_resume_via_firmware(void) { return false; }
 static inline bool pm_suspend_no_platform(void) { return false; }
 static inline bool pm_suspend_default_s2idle(void) { return false; }
+static inline bool pm_hibernation_mode_is_suspend(void) { return false; }
 
 static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
 static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }

kernel/power/hibernate.c

@@ -80,6 +80,17 @@ static const struct platform_hibernation_ops *hibernation_ops;
 
 static atomic_t hibernate_atomic = ATOMIC_INIT(1);
 
+#ifdef CONFIG_SUSPEND
+/**
+ * pm_hibernation_mode_is_suspend - Check if hibernation has been set to suspend
+ */
+bool pm_hibernation_mode_is_suspend(void)
+{
+	return hibernation_mode == HIBERNATION_SUSPEND;
+}
+EXPORT_SYMBOL_GPL(pm_hibernation_mode_is_suspend);
+#endif
+
 bool hibernate_acquire(void)
 {
 	return atomic_add_unless(&hibernate_atomic, -1, 0);