usbcore: add autosuspend/autoresume infrastructure

This patch (as739) adds the basic infrastructure for USB autosuspend
and autoresume.  The main features are:

	PM usage counters added to struct usb_device and struct
	usb_interface, indicating whether it's okay to autosuspend
	them or they are currently in use.

	Flag added to usb_device indicating whether the current
	suspend/resume operation originated from outside or as an
	autosuspend/autoresume.

	Flag added to usb_driver indicating whether the driver
	supports autosuspend.  If not, no device bound to the driver
	will be autosuspended.

	Mutex added to usb_device for protecting PM operations.
	Unlike the device semaphore, the locking rule for the pm_mutex
	is that you must acquire the locks going _up_ the device tree.

	New routines handling autosuspend/autoresume requests for
	interfaces and devices.

	Suspend and resume requests are propagated up the device tree
	(but not outside the USB subsystem).

	work_struct added to usb_device, for carrying out delayed
	autosuspend requests.

	Autoresume added (and autosuspend prevented) during probe and
	disconnect.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 5162cb370215..10688ad73c6d 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -49,6 +49,20 @@ static inline int usb_resume_both(struct usb_device *udev)
 
 #endif
 
+#ifdef CONFIG_USB_SUSPEND
+
+#define USB_AUTOSUSPEND_DELAY	(HZ*2)
+
+extern void usb_autosuspend_device(struct usb_device *udev, int dec_busy_cnt);
+extern int usb_autoresume_device(struct usb_device *udev, int inc_busy_cnt);
+
+#else
+
+#define usb_autosuspend_device(udev, dec_busy_cnt)	do {} while (0)
+#define usb_autoresume_device(udev, inc_busy_cnt)	0
+
+#endif
+
 extern struct bus_type usb_bus_type;
 extern struct usb_device_driver usb_generic_driver;