Introduce new top level suspend and hibernation callbacks

Introduce 'struct pm_ops' and 'struct pm_ext_ops' ('ext' meaning
'extended') representing suspend and hibernation operations for bus
types, device classes, device types and device drivers.

Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
objects, if defined, instead of the ->suspend(), ->resume(),
->suspend_late(), and ->resume_early() callbacks (the old callbacks
will be considered as legacy and gradually phased out).

The main purpose of doing this is to separate suspend (aka S2RAM and
standby) callbacks from hibernation callbacks in such a way that the
new callbacks won't take arguments and the semantics of each of them
will be clearly specified.  This has been requested for multiple
times by many people, including Linus himself, and the reason is that
within the current scheme if ->resume() is called, for example, it's
difficult to say why it's been called (ie. is it a resume from RAM or
from hibernation or a suspend/hibernation failure etc.?).

The second purpose is to make the suspend/hibernation callbacks more
flexible so that device drivers can handle more than they can within
the current scheme.  For example, some drivers may need to prevent
new children of the device from being registered before their
->suspend() callbacks are executed or they may want to carry out some
operations requiring the availability of some other devices, not
directly bound via the parent-child relationship, in order to prepare
for the execution of ->suspend(), etc.

Ultimately, we'd like to stop using the freezing of tasks for suspend
and therefore the drivers' suspend/hibernation code will have to take
care of the handling of the user space during suspend/hibernation.
That, in turn, would be difficult within the current scheme, without
the new ->prepare() and ->complete() callbacks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 6a2d04c011b..f71a78d123a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -68,6 +68,8 @@ struct bus_type {
         int (*resume_early)(struct device *dev);
         int (*resume)(struct device *dev);
 
+        struct pm_ext_ops *pm;
+
         struct bus_type_private *p;
 };
 
@@ -131,6 +133,8 @@ struct device_driver {
         int (*resume) (struct device *dev);
         struct attribute_group **groups;
 
+        struct pm_ops *pm;
+
         struct driver_private *p;
 };
 
@@ -197,6 +201,8 @@ struct class {
 
         int (*suspend)(struct device *dev, pm_message_t state);
         int (*resume)(struct device *dev);
+
+        struct pm_ops *pm;
 };
 
 extern int __must_check class_register(struct class *class);
@@ -248,8 +254,11 @@ struct device_type {
         struct attribute_group **groups;
         int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
         void (*release)(struct device *dev);
+
         int (*suspend)(struct device *dev, pm_message_t state);
         int (*resume)(struct device *dev);
+
+        struct pm_ops *pm;
 };
 
 /* interface for exporting device attributes */