1 // SPDX-License-Identifier: GPL-2.0
4  * offload.c - USB offload related functions
8  * Author: Guan-Yu Lin
11 #include <linux/usb.h>
13 #include "usb.h"
16  * usb_offload_get - increment the offload_usage of a USB device
17  * @udev: the USB device to increment its offload_usage
20  * enabled on this usb_device; that is, another entity is actively handling USB
21  * transfers. This information allows the USB driver to adjust its power
22  * management policy based on offload activity.
31 		return -ENODEV;  in usb_offload_get()
33 	if (pm_runtime_get_if_active(&udev->dev) != 1) {  in usb_offload_get()
34 		ret = -EBUSY;  in usb_offload_get()
38 	spin_lock(&udev->offload_lock);  in usb_offload_get()
40 	if (udev->offload_pm_locked) {  in usb_offload_get()
41 		ret = -EAGAIN;  in usb_offload_get()
45 	udev->offload_usage++;  in usb_offload_get()
48 	spin_unlock(&udev->offload_lock);  in usb_offload_get()
49 	pm_runtime_put_autosuspend(&udev->dev);  in usb_offload_get()
58  * usb_offload_put - drop the offload_usage of a USB device
59  * @udev: the USB device to drop its offload_usage
62  * a USB device. This information allows the USB driver to adjust its power
63  * management policy based on offload activity.
72 		return -ENODEV;  in usb_offload_put()
74 	if (pm_runtime_get_if_active(&udev->dev) != 1) {  in usb_offload_put()
75 		ret = -EBUSY;  in usb_offload_put()
79 	spin_lock(&udev->offload_lock);  in usb_offload_put()
81 	if (udev->offload_pm_locked) {  in usb_offload_put()
82 		ret = -EAGAIN;  in usb_offload_put()
87 	if (udev->offload_usage)  in usb_offload_put()
88 		udev->offload_usage--;  in usb_offload_put()
91 	spin_unlock(&udev->offload_lock);  in usb_offload_put()
92 	pm_runtime_put_autosuspend(&udev->dev);  in usb_offload_put()
101  * usb_offload_check - check offload activities on a USB device
102  * @udev: the USB device to check its offload activity.
104  * Check if there are any offload activity on the USB device right now. This
109  * ensure the device itself and the downstream usb devices are all marked as
114 bool usb_offload_check(struct usb_device *udev) __must_hold(&udev->dev->mutex)  in usb_offload_check()
120 	if (udev->offload_usage)  in usb_offload_check()
137  * usb_offload_set_pm_locked - set the PM lock state of a USB device
138  * @udev: the USB device to modify
148 	spin_lock(&udev->offload_lock);  in usb_offload_set_pm_locked()
149 	udev->offload_pm_locked = locked;  in usb_offload_set_pm_locked()
150 	spin_unlock(&udev->offload_lock);  in usb_offload_set_pm_locked()