xref: /openbmc/linux/drivers/usb/core/driver.c (revision 9ac8d3fb)
1 /*
2  * drivers/usb/driver.c - most of the driver model stuff for usb
3  *
4  * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
5  *
6  * based on drivers/usb/usb.c which had the following copyrights:
7  *	(C) Copyright Linus Torvalds 1999
8  *	(C) Copyright Johannes Erdfelt 1999-2001
9  *	(C) Copyright Andreas Gal 1999
10  *	(C) Copyright Gregory P. Smith 1999
11  *	(C) Copyright Deti Fliegl 1999 (new USB architecture)
12  *	(C) Copyright Randy Dunlap 2000
13  *	(C) Copyright David Brownell 2000-2004
14  *	(C) Copyright Yggdrasil Computing, Inc. 2000
15  *		(usb_device_id matching changes by Adam J. Richter)
16  *	(C) Copyright Greg Kroah-Hartman 2002-2003
17  *
18  * NOTE! This is not actually a driver at all, rather this is
19  * just a collection of helper routines that implement the
20  * matching, probing, releasing, suspending and resuming for
21  * real drivers.
22  *
23  */
24 
25 #include <linux/device.h>
26 #include <linux/usb.h>
27 #include <linux/usb/quirks.h>
28 #include <linux/workqueue.h>
29 #include "hcd.h"
30 #include "usb.h"
31 
32 
33 #ifdef CONFIG_HOTPLUG
34 
35 /*
36  * Adds a new dynamic USBdevice ID to this driver,
37  * and cause the driver to probe for all devices again.
38  */
39 ssize_t usb_store_new_id(struct usb_dynids *dynids,
40 			 struct device_driver *driver,
41 			 const char *buf, size_t count)
42 {
43 	struct usb_dynid *dynid;
44 	u32 idVendor = 0;
45 	u32 idProduct = 0;
46 	int fields = 0;
47 	int retval = 0;
48 
49 	fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
50 	if (fields < 2)
51 		return -EINVAL;
52 
53 	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
54 	if (!dynid)
55 		return -ENOMEM;
56 
57 	INIT_LIST_HEAD(&dynid->node);
58 	dynid->id.idVendor = idVendor;
59 	dynid->id.idProduct = idProduct;
60 	dynid->id.match_flags = USB_DEVICE_ID_MATCH_DEVICE;
61 
62 	spin_lock(&dynids->lock);
63 	list_add_tail(&dynid->node, &dynids->list);
64 	spin_unlock(&dynids->lock);
65 
66 	if (get_driver(driver)) {
67 		retval = driver_attach(driver);
68 		put_driver(driver);
69 	}
70 
71 	if (retval)
72 		return retval;
73 	return count;
74 }
75 EXPORT_SYMBOL_GPL(usb_store_new_id);
76 
77 static ssize_t store_new_id(struct device_driver *driver,
78 			    const char *buf, size_t count)
79 {
80 	struct usb_driver *usb_drv = to_usb_driver(driver);
81 
82 	return usb_store_new_id(&usb_drv->dynids, driver, buf, count);
83 }
84 static DRIVER_ATTR(new_id, S_IWUSR, NULL, store_new_id);
85 
86 static int usb_create_newid_file(struct usb_driver *usb_drv)
87 {
88 	int error = 0;
89 
90 	if (usb_drv->no_dynamic_id)
91 		goto exit;
92 
93 	if (usb_drv->probe != NULL)
94 		error = driver_create_file(&usb_drv->drvwrap.driver,
95 					   &driver_attr_new_id);
96 exit:
97 	return error;
98 }
99 
100 static void usb_remove_newid_file(struct usb_driver *usb_drv)
101 {
102 	if (usb_drv->no_dynamic_id)
103 		return;
104 
105 	if (usb_drv->probe != NULL)
106 		driver_remove_file(&usb_drv->drvwrap.driver,
107 				   &driver_attr_new_id);
108 }
109 
110 static void usb_free_dynids(struct usb_driver *usb_drv)
111 {
112 	struct usb_dynid *dynid, *n;
113 
114 	spin_lock(&usb_drv->dynids.lock);
115 	list_for_each_entry_safe(dynid, n, &usb_drv->dynids.list, node) {
116 		list_del(&dynid->node);
117 		kfree(dynid);
118 	}
119 	spin_unlock(&usb_drv->dynids.lock);
120 }
121 #else
122 static inline int usb_create_newid_file(struct usb_driver *usb_drv)
123 {
124 	return 0;
125 }
126 
127 static void usb_remove_newid_file(struct usb_driver *usb_drv)
128 {
129 }
130 
131 static inline void usb_free_dynids(struct usb_driver *usb_drv)
132 {
133 }
134 #endif
135 
136 static const struct usb_device_id *usb_match_dynamic_id(struct usb_interface *intf,
137 							struct usb_driver *drv)
138 {
139 	struct usb_dynid *dynid;
140 
141 	spin_lock(&drv->dynids.lock);
142 	list_for_each_entry(dynid, &drv->dynids.list, node) {
143 		if (usb_match_one_id(intf, &dynid->id)) {
144 			spin_unlock(&drv->dynids.lock);
145 			return &dynid->id;
146 		}
147 	}
148 	spin_unlock(&drv->dynids.lock);
149 	return NULL;
150 }
151 
152 
153 /* called from driver core with dev locked */
154 static int usb_probe_device(struct device *dev)
155 {
156 	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
157 	struct usb_device *udev;
158 	int error = -ENODEV;
159 
160 	dev_dbg(dev, "%s\n", __func__);
161 
162 	if (!is_usb_device(dev))	/* Sanity check */
163 		return error;
164 
165 	udev = to_usb_device(dev);
166 
167 	/* TODO: Add real matching code */
168 
169 	/* The device should always appear to be in use
170 	 * unless the driver suports autosuspend.
171 	 */
172 	udev->pm_usage_cnt = !(udriver->supports_autosuspend);
173 
174 	error = udriver->probe(udev);
175 	return error;
176 }
177 
178 /* called from driver core with dev locked */
179 static int usb_unbind_device(struct device *dev)
180 {
181 	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
182 
183 	udriver->disconnect(to_usb_device(dev));
184 	return 0;
185 }
186 
187 
188 /* called from driver core with dev locked */
189 static int usb_probe_interface(struct device *dev)
190 {
191 	struct usb_driver *driver = to_usb_driver(dev->driver);
192 	struct usb_interface *intf;
193 	struct usb_device *udev;
194 	const struct usb_device_id *id;
195 	int error = -ENODEV;
196 
197 	dev_dbg(dev, "%s\n", __func__);
198 
199 	if (is_usb_device(dev))		/* Sanity check */
200 		return error;
201 
202 	intf = to_usb_interface(dev);
203 	udev = interface_to_usbdev(intf);
204 	intf->needs_binding = 0;
205 
206 	if (udev->authorized == 0) {
207 		dev_err(&intf->dev, "Device is not authorized for usage\n");
208 		return -ENODEV;
209 	}
210 
211 	id = usb_match_id(intf, driver->id_table);
212 	if (!id)
213 		id = usb_match_dynamic_id(intf, driver);
214 	if (id) {
215 		dev_dbg(dev, "%s - got id\n", __func__);
216 
217 		error = usb_autoresume_device(udev);
218 		if (error)
219 			return error;
220 
221 		/* Interface "power state" doesn't correspond to any hardware
222 		 * state whatsoever.  We use it to record when it's bound to
223 		 * a driver that may start I/0:  it's not frozen/quiesced.
224 		 */
225 		mark_active(intf);
226 		intf->condition = USB_INTERFACE_BINDING;
227 
228 		/* The interface should always appear to be in use
229 		 * unless the driver suports autosuspend.
230 		 */
231 		intf->pm_usage_cnt = !(driver->supports_autosuspend);
232 
233 		/* Carry out a deferred switch to altsetting 0 */
234 		if (intf->needs_altsetting0) {
235 			usb_set_interface(udev, intf->altsetting[0].
236 					desc.bInterfaceNumber, 0);
237 			intf->needs_altsetting0 = 0;
238 		}
239 
240 		error = driver->probe(intf, id);
241 		if (error) {
242 			mark_quiesced(intf);
243 			intf->needs_remote_wakeup = 0;
244 			intf->condition = USB_INTERFACE_UNBOUND;
245 		} else
246 			intf->condition = USB_INTERFACE_BOUND;
247 
248 		usb_autosuspend_device(udev);
249 	}
250 
251 	return error;
252 }
253 
254 /* called from driver core with dev locked */
255 static int usb_unbind_interface(struct device *dev)
256 {
257 	struct usb_driver *driver = to_usb_driver(dev->driver);
258 	struct usb_interface *intf = to_usb_interface(dev);
259 	struct usb_device *udev;
260 	int error;
261 
262 	intf->condition = USB_INTERFACE_UNBINDING;
263 
264 	/* Autoresume for set_interface call below */
265 	udev = interface_to_usbdev(intf);
266 	error = usb_autoresume_device(udev);
267 
268 	/* Terminate all URBs for this interface unless the driver
269 	 * supports "soft" unbinding.
270 	 */
271 	if (!driver->soft_unbind)
272 		usb_disable_interface(udev, intf);
273 
274 	driver->disconnect(intf);
275 
276 	/* Reset other interface state.
277 	 * We cannot do a Set-Interface if the device is suspended or
278 	 * if it is prepared for a system sleep (since installing a new
279 	 * altsetting means creating new endpoint device entries).
280 	 * When either of these happens, defer the Set-Interface.
281 	 */
282 	if (!error && intf->dev.power.status == DPM_ON)
283 		usb_set_interface(udev, intf->altsetting[0].
284 				desc.bInterfaceNumber, 0);
285 	else
286 		intf->needs_altsetting0 = 1;
287 	usb_set_intfdata(intf, NULL);
288 
289 	intf->condition = USB_INTERFACE_UNBOUND;
290 	mark_quiesced(intf);
291 	intf->needs_remote_wakeup = 0;
292 
293 	if (!error)
294 		usb_autosuspend_device(udev);
295 
296 	return 0;
297 }
298 
299 /**
300  * usb_driver_claim_interface - bind a driver to an interface
301  * @driver: the driver to be bound
302  * @iface: the interface to which it will be bound; must be in the
303  *	usb device's active configuration
304  * @priv: driver data associated with that interface
305  *
306  * This is used by usb device drivers that need to claim more than one
307  * interface on a device when probing (audio and acm are current examples).
308  * No device driver should directly modify internal usb_interface or
309  * usb_device structure members.
310  *
311  * Few drivers should need to use this routine, since the most natural
312  * way to bind to an interface is to return the private data from
313  * the driver's probe() method.
314  *
315  * Callers must own the device lock, so driver probe() entries don't need
316  * extra locking, but other call contexts may need to explicitly claim that
317  * lock.
318  */
319 int usb_driver_claim_interface(struct usb_driver *driver,
320 				struct usb_interface *iface, void *priv)
321 {
322 	struct device *dev = &iface->dev;
323 	struct usb_device *udev = interface_to_usbdev(iface);
324 	int retval = 0;
325 
326 	if (dev->driver)
327 		return -EBUSY;
328 
329 	dev->driver = &driver->drvwrap.driver;
330 	usb_set_intfdata(iface, priv);
331 	iface->needs_binding = 0;
332 
333 	usb_pm_lock(udev);
334 	iface->condition = USB_INTERFACE_BOUND;
335 	mark_active(iface);
336 	iface->pm_usage_cnt = !(driver->supports_autosuspend);
337 	usb_pm_unlock(udev);
338 
339 	/* if interface was already added, bind now; else let
340 	 * the future device_add() bind it, bypassing probe()
341 	 */
342 	if (device_is_registered(dev))
343 		retval = device_bind_driver(dev);
344 
345 	return retval;
346 }
347 EXPORT_SYMBOL_GPL(usb_driver_claim_interface);
348 
349 /**
350  * usb_driver_release_interface - unbind a driver from an interface
351  * @driver: the driver to be unbound
352  * @iface: the interface from which it will be unbound
353  *
354  * This can be used by drivers to release an interface without waiting
355  * for their disconnect() methods to be called.  In typical cases this
356  * also causes the driver disconnect() method to be called.
357  *
358  * This call is synchronous, and may not be used in an interrupt context.
359  * Callers must own the device lock, so driver disconnect() entries don't
360  * need extra locking, but other call contexts may need to explicitly claim
361  * that lock.
362  */
363 void usb_driver_release_interface(struct usb_driver *driver,
364 					struct usb_interface *iface)
365 {
366 	struct device *dev = &iface->dev;
367 	struct usb_device *udev = interface_to_usbdev(iface);
368 
369 	/* this should never happen, don't release something that's not ours */
370 	if (!dev->driver || dev->driver != &driver->drvwrap.driver)
371 		return;
372 
373 	/* don't release from within disconnect() */
374 	if (iface->condition != USB_INTERFACE_BOUND)
375 		return;
376 
377 	/* don't release if the interface hasn't been added yet */
378 	if (device_is_registered(dev)) {
379 		iface->condition = USB_INTERFACE_UNBINDING;
380 		device_release_driver(dev);
381 	}
382 
383 	dev->driver = NULL;
384 	usb_set_intfdata(iface, NULL);
385 
386 	usb_pm_lock(udev);
387 	iface->condition = USB_INTERFACE_UNBOUND;
388 	mark_quiesced(iface);
389 	iface->needs_remote_wakeup = 0;
390 	usb_pm_unlock(udev);
391 }
392 EXPORT_SYMBOL_GPL(usb_driver_release_interface);
393 
394 /* returns 0 if no match, 1 if match */
395 int usb_match_device(struct usb_device *dev, const struct usb_device_id *id)
396 {
397 	if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
398 	    id->idVendor != le16_to_cpu(dev->descriptor.idVendor))
399 		return 0;
400 
401 	if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
402 	    id->idProduct != le16_to_cpu(dev->descriptor.idProduct))
403 		return 0;
404 
405 	/* No need to test id->bcdDevice_lo != 0, since 0 is never
406 	   greater than any unsigned number. */
407 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO) &&
408 	    (id->bcdDevice_lo > le16_to_cpu(dev->descriptor.bcdDevice)))
409 		return 0;
410 
411 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI) &&
412 	    (id->bcdDevice_hi < le16_to_cpu(dev->descriptor.bcdDevice)))
413 		return 0;
414 
415 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS) &&
416 	    (id->bDeviceClass != dev->descriptor.bDeviceClass))
417 		return 0;
418 
419 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS) &&
420 	    (id->bDeviceSubClass != dev->descriptor.bDeviceSubClass))
421 		return 0;
422 
423 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
424 	    (id->bDeviceProtocol != dev->descriptor.bDeviceProtocol))
425 		return 0;
426 
427 	return 1;
428 }
429 
430 /* returns 0 if no match, 1 if match */
431 int usb_match_one_id(struct usb_interface *interface,
432 		     const struct usb_device_id *id)
433 {
434 	struct usb_host_interface *intf;
435 	struct usb_device *dev;
436 
437 	/* proc_connectinfo in devio.c may call us with id == NULL. */
438 	if (id == NULL)
439 		return 0;
440 
441 	intf = interface->cur_altsetting;
442 	dev = interface_to_usbdev(interface);
443 
444 	if (!usb_match_device(dev, id))
445 		return 0;
446 
447 	/* The interface class, subclass, and protocol should never be
448 	 * checked for a match if the device class is Vendor Specific,
449 	 * unless the match record specifies the Vendor ID. */
450 	if (dev->descriptor.bDeviceClass == USB_CLASS_VENDOR_SPEC &&
451 			!(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
452 			(id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |
453 				USB_DEVICE_ID_MATCH_INT_SUBCLASS |
454 				USB_DEVICE_ID_MATCH_INT_PROTOCOL)))
455 		return 0;
456 
457 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&
458 	    (id->bInterfaceClass != intf->desc.bInterfaceClass))
459 		return 0;
460 
461 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS) &&
462 	    (id->bInterfaceSubClass != intf->desc.bInterfaceSubClass))
463 		return 0;
464 
465 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL) &&
466 	    (id->bInterfaceProtocol != intf->desc.bInterfaceProtocol))
467 		return 0;
468 
469 	return 1;
470 }
471 EXPORT_SYMBOL_GPL(usb_match_one_id);
472 
473 /**
474  * usb_match_id - find first usb_device_id matching device or interface
475  * @interface: the interface of interest
476  * @id: array of usb_device_id structures, terminated by zero entry
477  *
478  * usb_match_id searches an array of usb_device_id's and returns
479  * the first one matching the device or interface, or null.
480  * This is used when binding (or rebinding) a driver to an interface.
481  * Most USB device drivers will use this indirectly, through the usb core,
482  * but some layered driver frameworks use it directly.
483  * These device tables are exported with MODULE_DEVICE_TABLE, through
484  * modutils, to support the driver loading functionality of USB hotplugging.
485  *
486  * What Matches:
487  *
488  * The "match_flags" element in a usb_device_id controls which
489  * members are used.  If the corresponding bit is set, the
490  * value in the device_id must match its corresponding member
491  * in the device or interface descriptor, or else the device_id
492  * does not match.
493  *
494  * "driver_info" is normally used only by device drivers,
495  * but you can create a wildcard "matches anything" usb_device_id
496  * as a driver's "modules.usbmap" entry if you provide an id with
497  * only a nonzero "driver_info" field.  If you do this, the USB device
498  * driver's probe() routine should use additional intelligence to
499  * decide whether to bind to the specified interface.
500  *
501  * What Makes Good usb_device_id Tables:
502  *
503  * The match algorithm is very simple, so that intelligence in
504  * driver selection must come from smart driver id records.
505  * Unless you have good reasons to use another selection policy,
506  * provide match elements only in related groups, and order match
507  * specifiers from specific to general.  Use the macros provided
508  * for that purpose if you can.
509  *
510  * The most specific match specifiers use device descriptor
511  * data.  These are commonly used with product-specific matches;
512  * the USB_DEVICE macro lets you provide vendor and product IDs,
513  * and you can also match against ranges of product revisions.
514  * These are widely used for devices with application or vendor
515  * specific bDeviceClass values.
516  *
517  * Matches based on device class/subclass/protocol specifications
518  * are slightly more general; use the USB_DEVICE_INFO macro, or
519  * its siblings.  These are used with single-function devices
520  * where bDeviceClass doesn't specify that each interface has
521  * its own class.
522  *
523  * Matches based on interface class/subclass/protocol are the
524  * most general; they let drivers bind to any interface on a
525  * multiple-function device.  Use the USB_INTERFACE_INFO
526  * macro, or its siblings, to match class-per-interface style
527  * devices (as recorded in bInterfaceClass).
528  *
529  * Note that an entry created by USB_INTERFACE_INFO won't match
530  * any interface if the device class is set to Vendor-Specific.
531  * This is deliberate; according to the USB spec the meanings of
532  * the interface class/subclass/protocol for these devices are also
533  * vendor-specific, and hence matching against a standard product
534  * class wouldn't work anyway.  If you really want to use an
535  * interface-based match for such a device, create a match record
536  * that also specifies the vendor ID.  (Unforunately there isn't a
537  * standard macro for creating records like this.)
538  *
539  * Within those groups, remember that not all combinations are
540  * meaningful.  For example, don't give a product version range
541  * without vendor and product IDs; or specify a protocol without
542  * its associated class and subclass.
543  */
544 const struct usb_device_id *usb_match_id(struct usb_interface *interface,
545 					 const struct usb_device_id *id)
546 {
547 	/* proc_connectinfo in devio.c may call us with id == NULL. */
548 	if (id == NULL)
549 		return NULL;
550 
551 	/* It is important to check that id->driver_info is nonzero,
552 	   since an entry that is all zeroes except for a nonzero
553 	   id->driver_info is the way to create an entry that
554 	   indicates that the driver want to examine every
555 	   device and interface. */
556 	for (; id->idVendor || id->idProduct || id->bDeviceClass ||
557 	       id->bInterfaceClass || id->driver_info; id++) {
558 		if (usb_match_one_id(interface, id))
559 			return id;
560 	}
561 
562 	return NULL;
563 }
564 EXPORT_SYMBOL_GPL(usb_match_id);
565 
566 static int usb_device_match(struct device *dev, struct device_driver *drv)
567 {
568 	/* devices and interfaces are handled separately */
569 	if (is_usb_device(dev)) {
570 
571 		/* interface drivers never match devices */
572 		if (!is_usb_device_driver(drv))
573 			return 0;
574 
575 		/* TODO: Add real matching code */
576 		return 1;
577 
578 	} else {
579 		struct usb_interface *intf;
580 		struct usb_driver *usb_drv;
581 		const struct usb_device_id *id;
582 
583 		/* device drivers never match interfaces */
584 		if (is_usb_device_driver(drv))
585 			return 0;
586 
587 		intf = to_usb_interface(dev);
588 		usb_drv = to_usb_driver(drv);
589 
590 		id = usb_match_id(intf, usb_drv->id_table);
591 		if (id)
592 			return 1;
593 
594 		id = usb_match_dynamic_id(intf, usb_drv);
595 		if (id)
596 			return 1;
597 	}
598 
599 	return 0;
600 }
601 
602 #ifdef	CONFIG_HOTPLUG
603 static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
604 {
605 	struct usb_device *usb_dev;
606 
607 	/* driver is often null here; dev_dbg() would oops */
608 	pr_debug("usb %s: uevent\n", dev_name(dev));
609 
610 	if (is_usb_device(dev))
611 		usb_dev = to_usb_device(dev);
612 	else {
613 		struct usb_interface *intf = to_usb_interface(dev);
614 		usb_dev = interface_to_usbdev(intf);
615 	}
616 
617 	if (usb_dev->devnum < 0) {
618 		pr_debug("usb %s: already deleted?\n", dev_name(dev));
619 		return -ENODEV;
620 	}
621 	if (!usb_dev->bus) {
622 		pr_debug("usb %s: bus removed?\n", dev_name(dev));
623 		return -ENODEV;
624 	}
625 
626 #ifdef	CONFIG_USB_DEVICEFS
627 	/* If this is available, userspace programs can directly read
628 	 * all the device descriptors we don't tell them about.  Or
629 	 * act as usermode drivers.
630 	 */
631 	if (add_uevent_var(env, "DEVICE=/proc/bus/usb/%03d/%03d",
632 			   usb_dev->bus->busnum, usb_dev->devnum))
633 		return -ENOMEM;
634 #endif
635 
636 	/* per-device configurations are common */
637 	if (add_uevent_var(env, "PRODUCT=%x/%x/%x",
638 			   le16_to_cpu(usb_dev->descriptor.idVendor),
639 			   le16_to_cpu(usb_dev->descriptor.idProduct),
640 			   le16_to_cpu(usb_dev->descriptor.bcdDevice)))
641 		return -ENOMEM;
642 
643 	/* class-based driver binding models */
644 	if (add_uevent_var(env, "TYPE=%d/%d/%d",
645 			   usb_dev->descriptor.bDeviceClass,
646 			   usb_dev->descriptor.bDeviceSubClass,
647 			   usb_dev->descriptor.bDeviceProtocol))
648 		return -ENOMEM;
649 
650 	return 0;
651 }
652 
653 #else
654 
655 static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
656 {
657 	return -ENODEV;
658 }
659 #endif	/* CONFIG_HOTPLUG */
660 
661 /**
662  * usb_register_device_driver - register a USB device (not interface) driver
663  * @new_udriver: USB operations for the device driver
664  * @owner: module owner of this driver.
665  *
666  * Registers a USB device driver with the USB core.  The list of
667  * unattached devices will be rescanned whenever a new driver is
668  * added, allowing the new driver to attach to any recognized devices.
669  * Returns a negative error code on failure and 0 on success.
670  */
671 int usb_register_device_driver(struct usb_device_driver *new_udriver,
672 		struct module *owner)
673 {
674 	int retval = 0;
675 
676 	if (usb_disabled())
677 		return -ENODEV;
678 
679 	new_udriver->drvwrap.for_devices = 1;
680 	new_udriver->drvwrap.driver.name = (char *) new_udriver->name;
681 	new_udriver->drvwrap.driver.bus = &usb_bus_type;
682 	new_udriver->drvwrap.driver.probe = usb_probe_device;
683 	new_udriver->drvwrap.driver.remove = usb_unbind_device;
684 	new_udriver->drvwrap.driver.owner = owner;
685 
686 	retval = driver_register(&new_udriver->drvwrap.driver);
687 
688 	if (!retval) {
689 		pr_info("%s: registered new device driver %s\n",
690 			usbcore_name, new_udriver->name);
691 		usbfs_update_special();
692 	} else {
693 		printk(KERN_ERR "%s: error %d registering device "
694 			"	driver %s\n",
695 			usbcore_name, retval, new_udriver->name);
696 	}
697 
698 	return retval;
699 }
700 EXPORT_SYMBOL_GPL(usb_register_device_driver);
701 
702 /**
703  * usb_deregister_device_driver - unregister a USB device (not interface) driver
704  * @udriver: USB operations of the device driver to unregister
705  * Context: must be able to sleep
706  *
707  * Unlinks the specified driver from the internal USB driver list.
708  */
709 void usb_deregister_device_driver(struct usb_device_driver *udriver)
710 {
711 	pr_info("%s: deregistering device driver %s\n",
712 			usbcore_name, udriver->name);
713 
714 	driver_unregister(&udriver->drvwrap.driver);
715 	usbfs_update_special();
716 }
717 EXPORT_SYMBOL_GPL(usb_deregister_device_driver);
718 
719 /**
720  * usb_register_driver - register a USB interface driver
721  * @new_driver: USB operations for the interface driver
722  * @owner: module owner of this driver.
723  * @mod_name: module name string
724  *
725  * Registers a USB interface driver with the USB core.  The list of
726  * unattached interfaces will be rescanned whenever a new driver is
727  * added, allowing the new driver to attach to any recognized interfaces.
728  * Returns a negative error code on failure and 0 on success.
729  *
730  * NOTE: if you want your driver to use the USB major number, you must call
731  * usb_register_dev() to enable that functionality.  This function no longer
732  * takes care of that.
733  */
734 int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
735 			const char *mod_name)
736 {
737 	int retval = 0;
738 
739 	if (usb_disabled())
740 		return -ENODEV;
741 
742 	new_driver->drvwrap.for_devices = 0;
743 	new_driver->drvwrap.driver.name = (char *) new_driver->name;
744 	new_driver->drvwrap.driver.bus = &usb_bus_type;
745 	new_driver->drvwrap.driver.probe = usb_probe_interface;
746 	new_driver->drvwrap.driver.remove = usb_unbind_interface;
747 	new_driver->drvwrap.driver.owner = owner;
748 	new_driver->drvwrap.driver.mod_name = mod_name;
749 	spin_lock_init(&new_driver->dynids.lock);
750 	INIT_LIST_HEAD(&new_driver->dynids.list);
751 
752 	retval = driver_register(&new_driver->drvwrap.driver);
753 
754 	if (!retval) {
755 		pr_info("%s: registered new interface driver %s\n",
756 			usbcore_name, new_driver->name);
757 		usbfs_update_special();
758 		usb_create_newid_file(new_driver);
759 	} else {
760 		printk(KERN_ERR "%s: error %d registering interface "
761 			"	driver %s\n",
762 			usbcore_name, retval, new_driver->name);
763 	}
764 
765 	return retval;
766 }
767 EXPORT_SYMBOL_GPL(usb_register_driver);
768 
769 /**
770  * usb_deregister - unregister a USB interface driver
771  * @driver: USB operations of the interface driver to unregister
772  * Context: must be able to sleep
773  *
774  * Unlinks the specified driver from the internal USB driver list.
775  *
776  * NOTE: If you called usb_register_dev(), you still need to call
777  * usb_deregister_dev() to clean up your driver's allocated minor numbers,
778  * this * call will no longer do it for you.
779  */
780 void usb_deregister(struct usb_driver *driver)
781 {
782 	pr_info("%s: deregistering interface driver %s\n",
783 			usbcore_name, driver->name);
784 
785 	usb_remove_newid_file(driver);
786 	usb_free_dynids(driver);
787 	driver_unregister(&driver->drvwrap.driver);
788 
789 	usbfs_update_special();
790 }
791 EXPORT_SYMBOL_GPL(usb_deregister);
792 
793 /* Forced unbinding of a USB interface driver, either because
794  * it doesn't support pre_reset/post_reset/reset_resume or
795  * because it doesn't support suspend/resume.
796  *
797  * The caller must hold @intf's device's lock, but not its pm_mutex
798  * and not @intf->dev.sem.
799  */
800 void usb_forced_unbind_intf(struct usb_interface *intf)
801 {
802 	struct usb_driver *driver = to_usb_driver(intf->dev.driver);
803 
804 	dev_dbg(&intf->dev, "forced unbind\n");
805 	usb_driver_release_interface(driver, intf);
806 
807 	/* Mark the interface for later rebinding */
808 	intf->needs_binding = 1;
809 }
810 
811 /* Delayed forced unbinding of a USB interface driver and scan
812  * for rebinding.
813  *
814  * The caller must hold @intf's device's lock, but not its pm_mutex
815  * and not @intf->dev.sem.
816  *
817  * Note: Rebinds will be skipped if a system sleep transition is in
818  * progress and the PM "complete" callback hasn't occurred yet.
819  */
820 void usb_rebind_intf(struct usb_interface *intf)
821 {
822 	int rc;
823 
824 	/* Delayed unbind of an existing driver */
825 	if (intf->dev.driver) {
826 		struct usb_driver *driver =
827 				to_usb_driver(intf->dev.driver);
828 
829 		dev_dbg(&intf->dev, "forced unbind\n");
830 		usb_driver_release_interface(driver, intf);
831 	}
832 
833 	/* Try to rebind the interface */
834 	if (intf->dev.power.status == DPM_ON) {
835 		intf->needs_binding = 0;
836 		rc = device_attach(&intf->dev);
837 		if (rc < 0)
838 			dev_warn(&intf->dev, "rebind failed: %d\n", rc);
839 	}
840 }
841 
842 #ifdef CONFIG_PM
843 
844 #define DO_UNBIND	0
845 #define DO_REBIND	1
846 
847 /* Unbind drivers for @udev's interfaces that don't support suspend/resume,
848  * or rebind interfaces that have been unbound, according to @action.
849  *
850  * The caller must hold @udev's device lock.
851  */
852 static void do_unbind_rebind(struct usb_device *udev, int action)
853 {
854 	struct usb_host_config	*config;
855 	int			i;
856 	struct usb_interface	*intf;
857 	struct usb_driver	*drv;
858 
859 	config = udev->actconfig;
860 	if (config) {
861 		for (i = 0; i < config->desc.bNumInterfaces; ++i) {
862 			intf = config->interface[i];
863 			switch (action) {
864 			case DO_UNBIND:
865 				if (intf->dev.driver) {
866 					drv = to_usb_driver(intf->dev.driver);
867 					if (!drv->suspend || !drv->resume)
868 						usb_forced_unbind_intf(intf);
869 				}
870 				break;
871 			case DO_REBIND:
872 				if (intf->needs_binding)
873 					usb_rebind_intf(intf);
874 				break;
875 			}
876 		}
877 	}
878 }
879 
880 /* Caller has locked udev's pm_mutex */
881 static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
882 {
883 	struct usb_device_driver	*udriver;
884 	int				status = 0;
885 
886 	if (udev->state == USB_STATE_NOTATTACHED ||
887 			udev->state == USB_STATE_SUSPENDED)
888 		goto done;
889 
890 	/* For devices that don't have a driver, we do a generic suspend. */
891 	if (udev->dev.driver)
892 		udriver = to_usb_device_driver(udev->dev.driver);
893 	else {
894 		udev->do_remote_wakeup = 0;
895 		udriver = &usb_generic_driver;
896 	}
897 	status = udriver->suspend(udev, msg);
898 
899  done:
900 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
901 	return status;
902 }
903 
904 /* Caller has locked udev's pm_mutex */
905 static int usb_resume_device(struct usb_device *udev)
906 {
907 	struct usb_device_driver	*udriver;
908 	int				status = 0;
909 
910 	if (udev->state == USB_STATE_NOTATTACHED)
911 		goto done;
912 
913 	/* Can't resume it if it doesn't have a driver. */
914 	if (udev->dev.driver == NULL) {
915 		status = -ENOTCONN;
916 		goto done;
917 	}
918 
919 	if (udev->quirks & USB_QUIRK_RESET_RESUME)
920 		udev->reset_resume = 1;
921 
922 	udriver = to_usb_device_driver(udev->dev.driver);
923 	status = udriver->resume(udev);
924 
925  done:
926 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
927 	if (status == 0)
928 		udev->autoresume_disabled = 0;
929 	return status;
930 }
931 
932 /* Caller has locked intf's usb_device's pm mutex */
933 static int usb_suspend_interface(struct usb_device *udev,
934 		struct usb_interface *intf, pm_message_t msg)
935 {
936 	struct usb_driver	*driver;
937 	int			status = 0;
938 
939 	/* with no hardware, USB interfaces only use FREEZE and ON states */
940 	if (udev->state == USB_STATE_NOTATTACHED || !is_active(intf))
941 		goto done;
942 
943 	if (intf->condition == USB_INTERFACE_UNBOUND)	/* This can't happen */
944 		goto done;
945 	driver = to_usb_driver(intf->dev.driver);
946 
947 	if (driver->suspend) {
948 		status = driver->suspend(intf, msg);
949 		if (status == 0)
950 			mark_quiesced(intf);
951 		else if (!udev->auto_pm)
952 			dev_err(&intf->dev, "%s error %d\n",
953 					"suspend", status);
954 	} else {
955 		/* Later we will unbind the driver and reprobe */
956 		intf->needs_binding = 1;
957 		dev_warn(&intf->dev, "no %s for driver %s?\n",
958 				"suspend", driver->name);
959 		mark_quiesced(intf);
960 	}
961 
962  done:
963 	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
964 	return status;
965 }
966 
967 /* Caller has locked intf's usb_device's pm_mutex */
968 static int usb_resume_interface(struct usb_device *udev,
969 		struct usb_interface *intf, int reset_resume)
970 {
971 	struct usb_driver	*driver;
972 	int			status = 0;
973 
974 	if (udev->state == USB_STATE_NOTATTACHED || is_active(intf))
975 		goto done;
976 
977 	/* Don't let autoresume interfere with unbinding */
978 	if (intf->condition == USB_INTERFACE_UNBINDING)
979 		goto done;
980 
981 	/* Can't resume it if it doesn't have a driver. */
982 	if (intf->condition == USB_INTERFACE_UNBOUND) {
983 
984 		/* Carry out a deferred switch to altsetting 0 */
985 		if (intf->needs_altsetting0 &&
986 				intf->dev.power.status == DPM_ON) {
987 			usb_set_interface(udev, intf->altsetting[0].
988 					desc.bInterfaceNumber, 0);
989 			intf->needs_altsetting0 = 0;
990 		}
991 		goto done;
992 	}
993 
994 	/* Don't resume if the interface is marked for rebinding */
995 	if (intf->needs_binding)
996 		goto done;
997 	driver = to_usb_driver(intf->dev.driver);
998 
999 	if (reset_resume) {
1000 		if (driver->reset_resume) {
1001 			status = driver->reset_resume(intf);
1002 			if (status)
1003 				dev_err(&intf->dev, "%s error %d\n",
1004 						"reset_resume", status);
1005 		} else {
1006 			intf->needs_binding = 1;
1007 			dev_warn(&intf->dev, "no %s for driver %s?\n",
1008 					"reset_resume", driver->name);
1009 		}
1010 	} else {
1011 		if (driver->resume) {
1012 			status = driver->resume(intf);
1013 			if (status)
1014 				dev_err(&intf->dev, "%s error %d\n",
1015 						"resume", status);
1016 		} else {
1017 			intf->needs_binding = 1;
1018 			dev_warn(&intf->dev, "no %s for driver %s?\n",
1019 					"resume", driver->name);
1020 		}
1021 	}
1022 
1023 done:
1024 	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
1025 	if (status == 0 && intf->condition == USB_INTERFACE_BOUND)
1026 		mark_active(intf);
1027 
1028 	/* Later we will unbind the driver and/or reprobe, if necessary */
1029 	return status;
1030 }
1031 
1032 #ifdef	CONFIG_USB_SUSPEND
1033 
1034 /* Internal routine to check whether we may autosuspend a device. */
1035 static int autosuspend_check(struct usb_device *udev, int reschedule)
1036 {
1037 	int			i;
1038 	struct usb_interface	*intf;
1039 	unsigned long		suspend_time, j;
1040 
1041 	/* For autosuspend, fail fast if anything is in use or autosuspend
1042 	 * is disabled.  Also fail if any interfaces require remote wakeup
1043 	 * but it isn't available.
1044 	 */
1045 	if (udev->pm_usage_cnt > 0)
1046 		return -EBUSY;
1047 	if (udev->autosuspend_delay < 0 || udev->autosuspend_disabled)
1048 		return -EPERM;
1049 
1050 	suspend_time = udev->last_busy + udev->autosuspend_delay;
1051 	if (udev->actconfig) {
1052 		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
1053 			intf = udev->actconfig->interface[i];
1054 			if (!is_active(intf))
1055 				continue;
1056 			if (intf->pm_usage_cnt > 0)
1057 				return -EBUSY;
1058 			if (intf->needs_remote_wakeup &&
1059 					!udev->do_remote_wakeup) {
1060 				dev_dbg(&udev->dev, "remote wakeup needed "
1061 						"for autosuspend\n");
1062 				return -EOPNOTSUPP;
1063 			}
1064 
1065 			/* Don't allow autosuspend if the device will need
1066 			 * a reset-resume and any of its interface drivers
1067 			 * doesn't include support.
1068 			 */
1069 			if (udev->quirks & USB_QUIRK_RESET_RESUME) {
1070 				struct usb_driver *driver;
1071 
1072 				driver = to_usb_driver(intf->dev.driver);
1073 				if (!driver->reset_resume ||
1074 				    intf->needs_remote_wakeup)
1075 					return -EOPNOTSUPP;
1076 			}
1077 		}
1078 	}
1079 
1080 	/* If everything is okay but the device hasn't been idle for long
1081 	 * enough, queue a delayed autosuspend request.  If the device
1082 	 * _has_ been idle for long enough and the reschedule flag is set,
1083 	 * likewise queue a delayed (1 second) autosuspend request.
1084 	 */
1085 	j = jiffies;
1086 	if (time_before(j, suspend_time))
1087 		reschedule = 1;
1088 	else
1089 		suspend_time = j + HZ;
1090 	if (reschedule) {
1091 		if (!timer_pending(&udev->autosuspend.timer)) {
1092 			queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
1093 				round_jiffies_relative(suspend_time - j));
1094 		}
1095 		return -EAGAIN;
1096 	}
1097 	return 0;
1098 }
1099 
1100 #else
1101 
1102 static inline int autosuspend_check(struct usb_device *udev, int reschedule)
1103 {
1104 	return 0;
1105 }
1106 
1107 #endif	/* CONFIG_USB_SUSPEND */
1108 
1109 /**
1110  * usb_suspend_both - suspend a USB device and its interfaces
1111  * @udev: the usb_device to suspend
1112  * @msg: Power Management message describing this state transition
1113  *
1114  * This is the central routine for suspending USB devices.  It calls the
1115  * suspend methods for all the interface drivers in @udev and then calls
1116  * the suspend method for @udev itself.  If an error occurs at any stage,
1117  * all the interfaces which were suspended are resumed so that they remain
1118  * in the same state as the device.
1119  *
1120  * If an autosuspend is in progress (@udev->auto_pm is set), the routine
1121  * checks first to make sure that neither the device itself or any of its
1122  * active interfaces is in use (pm_usage_cnt is greater than 0).  If they
1123  * are, the autosuspend fails.
1124  *
1125  * If the suspend succeeds, the routine recursively queues an autosuspend
1126  * request for @udev's parent device, thereby propagating the change up
1127  * the device tree.  If all of the parent's children are now suspended,
1128  * the parent will autosuspend in turn.
1129  *
1130  * The suspend method calls are subject to mutual exclusion under control
1131  * of @udev's pm_mutex.  Many of these calls are also under the protection
1132  * of @udev's device lock (including all requests originating outside the
1133  * USB subsystem), but autosuspend requests generated by a child device or
1134  * interface driver may not be.  Usbcore will insure that the method calls
1135  * do not arrive during bind, unbind, or reset operations.  However, drivers
1136  * must be prepared to handle suspend calls arriving at unpredictable times.
1137  * The only way to block such calls is to do an autoresume (preventing
1138  * autosuspends) while holding @udev's device lock (preventing outside
1139  * suspends).
1140  *
1141  * The caller must hold @udev->pm_mutex.
1142  *
1143  * This routine can run only in process context.
1144  */
1145 static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
1146 {
1147 	int			status = 0;
1148 	int			i = 0;
1149 	struct usb_interface	*intf;
1150 	struct usb_device	*parent = udev->parent;
1151 
1152 	if (udev->state == USB_STATE_NOTATTACHED ||
1153 			udev->state == USB_STATE_SUSPENDED)
1154 		goto done;
1155 
1156 	udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
1157 
1158 	if (udev->auto_pm) {
1159 		status = autosuspend_check(udev, 0);
1160 		if (status < 0)
1161 			goto done;
1162 	}
1163 
1164 	/* Suspend all the interfaces and then udev itself */
1165 	if (udev->actconfig) {
1166 		for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
1167 			intf = udev->actconfig->interface[i];
1168 			status = usb_suspend_interface(udev, intf, msg);
1169 			if (status != 0)
1170 				break;
1171 		}
1172 	}
1173 	if (status == 0)
1174 		status = usb_suspend_device(udev, msg);
1175 
1176 	/* If the suspend failed, resume interfaces that did get suspended */
1177 	if (status != 0) {
1178 		while (--i >= 0) {
1179 			intf = udev->actconfig->interface[i];
1180 			usb_resume_interface(udev, intf, 0);
1181 		}
1182 
1183 		/* Try another autosuspend when the interfaces aren't busy */
1184 		if (udev->auto_pm)
1185 			autosuspend_check(udev, status == -EBUSY);
1186 
1187 	/* If the suspend succeeded then prevent any more URB submissions,
1188 	 * flush any outstanding URBs, and propagate the suspend up the tree.
1189 	 */
1190 	} else {
1191 		cancel_delayed_work(&udev->autosuspend);
1192 		udev->can_submit = 0;
1193 		for (i = 0; i < 16; ++i) {
1194 			usb_hcd_flush_endpoint(udev, udev->ep_out[i]);
1195 			usb_hcd_flush_endpoint(udev, udev->ep_in[i]);
1196 		}
1197 
1198 		/* If this is just a FREEZE or a PRETHAW, udev might
1199 		 * not really be suspended.  Only true suspends get
1200 		 * propagated up the device tree.
1201 		 */
1202 		if (parent && udev->state == USB_STATE_SUSPENDED)
1203 			usb_autosuspend_device(parent);
1204 	}
1205 
1206  done:
1207 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
1208 	return status;
1209 }
1210 
1211 /**
1212  * usb_resume_both - resume a USB device and its interfaces
1213  * @udev: the usb_device to resume
1214  *
1215  * This is the central routine for resuming USB devices.  It calls the
1216  * the resume method for @udev and then calls the resume methods for all
1217  * the interface drivers in @udev.
1218  *
1219  * Before starting the resume, the routine calls itself recursively for
1220  * the parent device of @udev, thereby propagating the change up the device
1221  * tree and assuring that @udev will be able to resume.  If the parent is
1222  * unable to resume successfully, the routine fails.
1223  *
1224  * The resume method calls are subject to mutual exclusion under control
1225  * of @udev's pm_mutex.  Many of these calls are also under the protection
1226  * of @udev's device lock (including all requests originating outside the
1227  * USB subsystem), but autoresume requests generated by a child device or
1228  * interface driver may not be.  Usbcore will insure that the method calls
1229  * do not arrive during bind, unbind, or reset operations.  However, drivers
1230  * must be prepared to handle resume calls arriving at unpredictable times.
1231  * The only way to block such calls is to do an autoresume (preventing
1232  * other autoresumes) while holding @udev's device lock (preventing outside
1233  * resumes).
1234  *
1235  * The caller must hold @udev->pm_mutex.
1236  *
1237  * This routine can run only in process context.
1238  */
1239 static int usb_resume_both(struct usb_device *udev)
1240 {
1241 	int			status = 0;
1242 	int			i;
1243 	struct usb_interface	*intf;
1244 	struct usb_device	*parent = udev->parent;
1245 
1246 	cancel_delayed_work(&udev->autosuspend);
1247 	if (udev->state == USB_STATE_NOTATTACHED) {
1248 		status = -ENODEV;
1249 		goto done;
1250 	}
1251 	udev->can_submit = 1;
1252 
1253 	/* Propagate the resume up the tree, if necessary */
1254 	if (udev->state == USB_STATE_SUSPENDED) {
1255 		if (udev->auto_pm && udev->autoresume_disabled) {
1256 			status = -EPERM;
1257 			goto done;
1258 		}
1259 		if (parent) {
1260 			status = usb_autoresume_device(parent);
1261 			if (status == 0) {
1262 				status = usb_resume_device(udev);
1263 				if (status || udev->state ==
1264 						USB_STATE_NOTATTACHED) {
1265 					usb_autosuspend_device(parent);
1266 
1267 					/* It's possible usb_resume_device()
1268 					 * failed after the port was
1269 					 * unsuspended, causing udev to be
1270 					 * logically disconnected.  We don't
1271 					 * want usb_disconnect() to autosuspend
1272 					 * the parent again, so tell it that
1273 					 * udev disconnected while still
1274 					 * suspended. */
1275 					if (udev->state ==
1276 							USB_STATE_NOTATTACHED)
1277 						udev->discon_suspended = 1;
1278 				}
1279 			}
1280 		} else {
1281 
1282 			/* We can't progagate beyond the USB subsystem,
1283 			 * so if a root hub's controller is suspended
1284 			 * then we're stuck. */
1285 			status = usb_resume_device(udev);
1286 		}
1287 	} else if (udev->reset_resume)
1288 		status = usb_resume_device(udev);
1289 
1290 	if (status == 0 && udev->actconfig) {
1291 		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
1292 			intf = udev->actconfig->interface[i];
1293 			usb_resume_interface(udev, intf, udev->reset_resume);
1294 		}
1295 	}
1296 
1297  done:
1298 	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
1299 	if (!status)
1300 		udev->reset_resume = 0;
1301 	return status;
1302 }
1303 
1304 #ifdef CONFIG_USB_SUSPEND
1305 
1306 /* Internal routine to adjust a device's usage counter and change
1307  * its autosuspend state.
1308  */
1309 static int usb_autopm_do_device(struct usb_device *udev, int inc_usage_cnt)
1310 {
1311 	int	status = 0;
1312 
1313 	usb_pm_lock(udev);
1314 	udev->auto_pm = 1;
1315 	udev->pm_usage_cnt += inc_usage_cnt;
1316 	WARN_ON(udev->pm_usage_cnt < 0);
1317 	if (inc_usage_cnt)
1318 		udev->last_busy = jiffies;
1319 	if (inc_usage_cnt >= 0 && udev->pm_usage_cnt > 0) {
1320 		if (udev->state == USB_STATE_SUSPENDED)
1321 			status = usb_resume_both(udev);
1322 		if (status != 0)
1323 			udev->pm_usage_cnt -= inc_usage_cnt;
1324 		else if (inc_usage_cnt)
1325 			udev->last_busy = jiffies;
1326 	} else if (inc_usage_cnt <= 0 && udev->pm_usage_cnt <= 0) {
1327 		status = usb_suspend_both(udev, PMSG_SUSPEND);
1328 	}
1329 	usb_pm_unlock(udev);
1330 	return status;
1331 }
1332 
1333 /* usb_autosuspend_work - callback routine to autosuspend a USB device */
1334 void usb_autosuspend_work(struct work_struct *work)
1335 {
1336 	struct usb_device *udev =
1337 		container_of(work, struct usb_device, autosuspend.work);
1338 
1339 	usb_autopm_do_device(udev, 0);
1340 }
1341 
1342 /**
1343  * usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
1344  * @udev: the usb_device to autosuspend
1345  *
1346  * This routine should be called when a core subsystem is finished using
1347  * @udev and wants to allow it to autosuspend.  Examples would be when
1348  * @udev's device file in usbfs is closed or after a configuration change.
1349  *
1350  * @udev's usage counter is decremented.  If it or any of the usage counters
1351  * for an active interface is greater than 0, no autosuspend request will be
1352  * queued.  (If an interface driver does not support autosuspend then its
1353  * usage counter is permanently positive.)  Furthermore, if an interface
1354  * driver requires remote-wakeup capability during autosuspend but remote
1355  * wakeup is disabled, the autosuspend will fail.
1356  *
1357  * Often the caller will hold @udev's device lock, but this is not
1358  * necessary.
1359  *
1360  * This routine can run only in process context.
1361  */
1362 void usb_autosuspend_device(struct usb_device *udev)
1363 {
1364 	int	status;
1365 
1366 	status = usb_autopm_do_device(udev, -1);
1367 	dev_vdbg(&udev->dev, "%s: cnt %d\n",
1368 			__func__, udev->pm_usage_cnt);
1369 }
1370 
1371 /**
1372  * usb_try_autosuspend_device - attempt an autosuspend of a USB device and its interfaces
1373  * @udev: the usb_device to autosuspend
1374  *
1375  * This routine should be called when a core subsystem thinks @udev may
1376  * be ready to autosuspend.
1377  *
1378  * @udev's usage counter left unchanged.  If it or any of the usage counters
1379  * for an active interface is greater than 0, or autosuspend is not allowed
1380  * for any other reason, no autosuspend request will be queued.
1381  *
1382  * This routine can run only in process context.
1383  */
1384 void usb_try_autosuspend_device(struct usb_device *udev)
1385 {
1386 	usb_autopm_do_device(udev, 0);
1387 	dev_vdbg(&udev->dev, "%s: cnt %d\n",
1388 			__func__, udev->pm_usage_cnt);
1389 }
1390 
1391 /**
1392  * usb_autoresume_device - immediately autoresume a USB device and its interfaces
1393  * @udev: the usb_device to autoresume
1394  *
1395  * This routine should be called when a core subsystem wants to use @udev
1396  * and needs to guarantee that it is not suspended.  No autosuspend will
1397  * occur until usb_autosuspend_device is called.  (Note that this will not
1398  * prevent suspend events originating in the PM core.)  Examples would be
1399  * when @udev's device file in usbfs is opened or when a remote-wakeup
1400  * request is received.
1401  *
1402  * @udev's usage counter is incremented to prevent subsequent autosuspends.
1403  * However if the autoresume fails then the usage counter is re-decremented.
1404  *
1405  * Often the caller will hold @udev's device lock, but this is not
1406  * necessary (and attempting it might cause deadlock).
1407  *
1408  * This routine can run only in process context.
1409  */
1410 int usb_autoresume_device(struct usb_device *udev)
1411 {
1412 	int	status;
1413 
1414 	status = usb_autopm_do_device(udev, 1);
1415 	dev_vdbg(&udev->dev, "%s: status %d cnt %d\n",
1416 			__func__, status, udev->pm_usage_cnt);
1417 	return status;
1418 }
1419 
1420 /* Internal routine to adjust an interface's usage counter and change
1421  * its device's autosuspend state.
1422  */
1423 static int usb_autopm_do_interface(struct usb_interface *intf,
1424 		int inc_usage_cnt)
1425 {
1426 	struct usb_device	*udev = interface_to_usbdev(intf);
1427 	int			status = 0;
1428 
1429 	usb_pm_lock(udev);
1430 	if (intf->condition == USB_INTERFACE_UNBOUND)
1431 		status = -ENODEV;
1432 	else {
1433 		udev->auto_pm = 1;
1434 		intf->pm_usage_cnt += inc_usage_cnt;
1435 		udev->last_busy = jiffies;
1436 		if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
1437 			if (udev->state == USB_STATE_SUSPENDED)
1438 				status = usb_resume_both(udev);
1439 			if (status != 0)
1440 				intf->pm_usage_cnt -= inc_usage_cnt;
1441 			else
1442 				udev->last_busy = jiffies;
1443 		} else if (inc_usage_cnt <= 0 && intf->pm_usage_cnt <= 0) {
1444 			status = usb_suspend_both(udev, PMSG_SUSPEND);
1445 		}
1446 	}
1447 	usb_pm_unlock(udev);
1448 	return status;
1449 }
1450 
1451 /**
1452  * usb_autopm_put_interface - decrement a USB interface's PM-usage counter
1453  * @intf: the usb_interface whose counter should be decremented
1454  *
1455  * This routine should be called by an interface driver when it is
1456  * finished using @intf and wants to allow it to autosuspend.  A typical
1457  * example would be a character-device driver when its device file is
1458  * closed.
1459  *
1460  * The routine decrements @intf's usage counter.  When the counter reaches
1461  * 0, a delayed autosuspend request for @intf's device is queued.  When
1462  * the delay expires, if @intf->pm_usage_cnt is still <= 0 along with all
1463  * the other usage counters for the sibling interfaces and @intf's
1464  * usb_device, the device and all its interfaces will be autosuspended.
1465  *
1466  * Note that @intf->pm_usage_cnt is owned by the interface driver.  The
1467  * core will not change its value other than the increment and decrement
1468  * in usb_autopm_get_interface and usb_autopm_put_interface.  The driver
1469  * may use this simple counter-oriented discipline or may set the value
1470  * any way it likes.
1471  *
1472  * If the driver has set @intf->needs_remote_wakeup then autosuspend will
1473  * take place only if the device's remote-wakeup facility is enabled.
1474  *
1475  * Suspend method calls queued by this routine can arrive at any time
1476  * while @intf is resumed and its usage counter is equal to 0.  They are
1477  * not protected by the usb_device's lock but only by its pm_mutex.
1478  * Drivers must provide their own synchronization.
1479  *
1480  * This routine can run only in process context.
1481  */
1482 void usb_autopm_put_interface(struct usb_interface *intf)
1483 {
1484 	int	status;
1485 
1486 	status = usb_autopm_do_interface(intf, -1);
1487 	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
1488 			__func__, status, intf->pm_usage_cnt);
1489 }
1490 EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
1491 
1492 /**
1493  * usb_autopm_get_interface - increment a USB interface's PM-usage counter
1494  * @intf: the usb_interface whose counter should be incremented
1495  *
1496  * This routine should be called by an interface driver when it wants to
1497  * use @intf and needs to guarantee that it is not suspended.  In addition,
1498  * the routine prevents @intf from being autosuspended subsequently.  (Note
1499  * that this will not prevent suspend events originating in the PM core.)
1500  * This prevention will persist until usb_autopm_put_interface() is called
1501  * or @intf is unbound.  A typical example would be a character-device
1502  * driver when its device file is opened.
1503  *
1504  *
1505  * The routine increments @intf's usage counter.  (However if the
1506  * autoresume fails then the counter is re-decremented.)  So long as the
1507  * counter is greater than 0, autosuspend will not be allowed for @intf
1508  * or its usb_device.  When the driver is finished using @intf it should
1509  * call usb_autopm_put_interface() to decrement the usage counter and
1510  * queue a delayed autosuspend request (if the counter is <= 0).
1511  *
1512  *
1513  * Note that @intf->pm_usage_cnt is owned by the interface driver.  The
1514  * core will not change its value other than the increment and decrement
1515  * in usb_autopm_get_interface and usb_autopm_put_interface.  The driver
1516  * may use this simple counter-oriented discipline or may set the value
1517  * any way it likes.
1518  *
1519  * Resume method calls generated by this routine can arrive at any time
1520  * while @intf is suspended.  They are not protected by the usb_device's
1521  * lock but only by its pm_mutex.  Drivers must provide their own
1522  * synchronization.
1523  *
1524  * This routine can run only in process context.
1525  */
1526 int usb_autopm_get_interface(struct usb_interface *intf)
1527 {
1528 	int	status;
1529 
1530 	status = usb_autopm_do_interface(intf, 1);
1531 	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
1532 			__func__, status, intf->pm_usage_cnt);
1533 	return status;
1534 }
1535 EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
1536 
1537 /**
1538  * usb_autopm_set_interface - set a USB interface's autosuspend state
1539  * @intf: the usb_interface whose state should be set
1540  *
1541  * This routine sets the autosuspend state of @intf's device according
1542  * to @intf's usage counter, which the caller must have set previously.
1543  * If the counter is <= 0, the device is autosuspended (if it isn't
1544  * already suspended and if nothing else prevents the autosuspend).  If
1545  * the counter is > 0, the device is autoresumed (if it isn't already
1546  * awake).
1547  */
1548 int usb_autopm_set_interface(struct usb_interface *intf)
1549 {
1550 	int	status;
1551 
1552 	status = usb_autopm_do_interface(intf, 0);
1553 	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
1554 			__func__, status, intf->pm_usage_cnt);
1555 	return status;
1556 }
1557 EXPORT_SYMBOL_GPL(usb_autopm_set_interface);
1558 
1559 #else
1560 
1561 void usb_autosuspend_work(struct work_struct *work)
1562 {}
1563 
1564 #endif /* CONFIG_USB_SUSPEND */
1565 
1566 /**
1567  * usb_external_suspend_device - external suspend of a USB device and its interfaces
1568  * @udev: the usb_device to suspend
1569  * @msg: Power Management message describing this state transition
1570  *
1571  * This routine handles external suspend requests: ones not generated
1572  * internally by a USB driver (autosuspend) but rather coming from the user
1573  * (via sysfs) or the PM core (system sleep).  The suspend will be carried
1574  * out regardless of @udev's usage counter or those of its interfaces,
1575  * and regardless of whether or not remote wakeup is enabled.  Of course,
1576  * interface drivers still have the option of failing the suspend (if
1577  * there are unsuspended children, for example).
1578  *
1579  * The caller must hold @udev's device lock.
1580  */
1581 int usb_external_suspend_device(struct usb_device *udev, pm_message_t msg)
1582 {
1583 	int	status;
1584 
1585 	do_unbind_rebind(udev, DO_UNBIND);
1586 	usb_pm_lock(udev);
1587 	udev->auto_pm = 0;
1588 	status = usb_suspend_both(udev, msg);
1589 	usb_pm_unlock(udev);
1590 	return status;
1591 }
1592 
1593 /**
1594  * usb_external_resume_device - external resume of a USB device and its interfaces
1595  * @udev: the usb_device to resume
1596  *
1597  * This routine handles external resume requests: ones not generated
1598  * internally by a USB driver (autoresume) but rather coming from the user
1599  * (via sysfs), the PM core (system resume), or the device itself (remote
1600  * wakeup).  @udev's usage counter is unaffected.
1601  *
1602  * The caller must hold @udev's device lock.
1603  */
1604 int usb_external_resume_device(struct usb_device *udev)
1605 {
1606 	int	status;
1607 
1608 	usb_pm_lock(udev);
1609 	udev->auto_pm = 0;
1610 	status = usb_resume_both(udev);
1611 	udev->last_busy = jiffies;
1612 	usb_pm_unlock(udev);
1613 	if (status == 0)
1614 		do_unbind_rebind(udev, DO_REBIND);
1615 
1616 	/* Now that the device is awake, we can start trying to autosuspend
1617 	 * it again. */
1618 	if (status == 0)
1619 		usb_try_autosuspend_device(udev);
1620 	return status;
1621 }
1622 
1623 int usb_suspend(struct device *dev, pm_message_t message)
1624 {
1625 	struct usb_device	*udev;
1626 
1627 	udev = to_usb_device(dev);
1628 
1629 	/* If udev is already suspended, we can skip this suspend and
1630 	 * we should also skip the upcoming system resume.  High-speed
1631 	 * root hubs are an exception; they need to resume whenever the
1632 	 * system wakes up in order for USB-PERSIST port handover to work
1633 	 * properly.
1634 	 */
1635 	if (udev->state == USB_STATE_SUSPENDED) {
1636 		if (udev->parent || udev->speed != USB_SPEED_HIGH)
1637 			udev->skip_sys_resume = 1;
1638 		return 0;
1639 	}
1640 
1641 	udev->skip_sys_resume = 0;
1642 	return usb_external_suspend_device(udev, message);
1643 }
1644 
1645 int usb_resume(struct device *dev)
1646 {
1647 	struct usb_device	*udev;
1648 
1649 	udev = to_usb_device(dev);
1650 
1651 	/* If udev->skip_sys_resume is set then udev was already suspended
1652 	 * when the system sleep started, so we don't want to resume it
1653 	 * during this system wakeup.
1654 	 */
1655 	if (udev->skip_sys_resume)
1656 		return 0;
1657 	return usb_external_resume_device(udev);
1658 }
1659 
1660 #endif /* CONFIG_PM */
1661 
1662 struct bus_type usb_bus_type = {
1663 	.name =		"usb",
1664 	.match =	usb_device_match,
1665 	.uevent =	usb_uevent,
1666 };
1667