xref: /linux/drivers/usb/core/usb.c (revision 6093a688a07da07808f0122f9aa2a3eed250d853)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * drivers/usb/core/usb.c
4  *
5  * (C) Copyright Linus Torvalds 1999
6  * (C) Copyright Johannes Erdfelt 1999-2001
7  * (C) Copyright Andreas Gal 1999
8  * (C) Copyright Gregory P. Smith 1999
9  * (C) Copyright Deti Fliegl 1999 (new USB architecture)
10  * (C) Copyright Randy Dunlap 2000
11  * (C) Copyright David Brownell 2000-2004
12  * (C) Copyright Yggdrasil Computing, Inc. 2000
13  *     (usb_device_id matching changes by Adam J. Richter)
14  * (C) Copyright Greg Kroah-Hartman 2002-2003
15  *
16  * Released under the GPLv2 only.
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  * generic USB things that the real drivers can use..
21  *
22  * Think of this as a "USB library" rather than anything else,
23  * with no callbacks.  Callbacks are evil.
24  */
25 
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/of.h>
29 #include <linux/string.h>
30 #include <linux/bitops.h>
31 #include <linux/slab.h>
32 #include <linux/kmod.h>
33 #include <linux/init.h>
34 #include <linux/spinlock.h>
35 #include <linux/errno.h>
36 #include <linux/usb.h>
37 #include <linux/usb/hcd.h>
38 #include <linux/mutex.h>
39 #include <linux/workqueue.h>
40 #include <linux/debugfs.h>
41 #include <linux/usb/of.h>
42 
43 #include <asm/io.h>
44 #include <linux/scatterlist.h>
45 #include <linux/mm.h>
46 #include <linux/dma-mapping.h>
47 
48 #include "hub.h"
49 
50 const char *usbcore_name = "usbcore";
51 
52 static bool nousb;	/* Disable USB when built into kernel image */
53 
54 module_param(nousb, bool, 0444);
55 
56 /*
57  * for external read access to <nousb>
58  */
59 int usb_disabled(void)
60 {
61 	return nousb;
62 }
63 EXPORT_SYMBOL_GPL(usb_disabled);
64 
65 #ifdef	CONFIG_PM
66 /* Default delay value, in seconds */
67 static int usb_autosuspend_delay = CONFIG_USB_AUTOSUSPEND_DELAY;
68 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
69 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
70 
71 #else
72 #define usb_autosuspend_delay		0
73 #endif
74 
75 static bool match_endpoint(struct usb_endpoint_descriptor *epd,
76 		struct usb_endpoint_descriptor **bulk_in,
77 		struct usb_endpoint_descriptor **bulk_out,
78 		struct usb_endpoint_descriptor **int_in,
79 		struct usb_endpoint_descriptor **int_out)
80 {
81 	switch (usb_endpoint_type(epd)) {
82 	case USB_ENDPOINT_XFER_BULK:
83 		if (usb_endpoint_dir_in(epd)) {
84 			if (bulk_in && !*bulk_in) {
85 				*bulk_in = epd;
86 				break;
87 			}
88 		} else {
89 			if (bulk_out && !*bulk_out) {
90 				*bulk_out = epd;
91 				break;
92 			}
93 		}
94 
95 		return false;
96 	case USB_ENDPOINT_XFER_INT:
97 		if (usb_endpoint_dir_in(epd)) {
98 			if (int_in && !*int_in) {
99 				*int_in = epd;
100 				break;
101 			}
102 		} else {
103 			if (int_out && !*int_out) {
104 				*int_out = epd;
105 				break;
106 			}
107 		}
108 
109 		return false;
110 	default:
111 		return false;
112 	}
113 
114 	return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
115 			(!int_in || *int_in) && (!int_out || *int_out);
116 }
117 
118 /**
119  * usb_find_common_endpoints() -- look up common endpoint descriptors
120  * @alt:	alternate setting to search
121  * @bulk_in:	pointer to descriptor pointer, or NULL
122  * @bulk_out:	pointer to descriptor pointer, or NULL
123  * @int_in:	pointer to descriptor pointer, or NULL
124  * @int_out:	pointer to descriptor pointer, or NULL
125  *
126  * Search the alternate setting's endpoint descriptors for the first bulk-in,
127  * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
128  * provided pointers (unless they are NULL).
129  *
130  * If a requested endpoint is not found, the corresponding pointer is set to
131  * NULL.
132  *
133  * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
134  */
135 int usb_find_common_endpoints(struct usb_host_interface *alt,
136 		struct usb_endpoint_descriptor **bulk_in,
137 		struct usb_endpoint_descriptor **bulk_out,
138 		struct usb_endpoint_descriptor **int_in,
139 		struct usb_endpoint_descriptor **int_out)
140 {
141 	struct usb_endpoint_descriptor *epd;
142 	int i;
143 
144 	if (bulk_in)
145 		*bulk_in = NULL;
146 	if (bulk_out)
147 		*bulk_out = NULL;
148 	if (int_in)
149 		*int_in = NULL;
150 	if (int_out)
151 		*int_out = NULL;
152 
153 	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
154 		epd = &alt->endpoint[i].desc;
155 
156 		if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
157 			return 0;
158 	}
159 
160 	return -ENXIO;
161 }
162 EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
163 
164 /**
165  * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
166  * @alt:	alternate setting to search
167  * @bulk_in:	pointer to descriptor pointer, or NULL
168  * @bulk_out:	pointer to descriptor pointer, or NULL
169  * @int_in:	pointer to descriptor pointer, or NULL
170  * @int_out:	pointer to descriptor pointer, or NULL
171  *
172  * Search the alternate setting's endpoint descriptors for the last bulk-in,
173  * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
174  * provided pointers (unless they are NULL).
175  *
176  * If a requested endpoint is not found, the corresponding pointer is set to
177  * NULL.
178  *
179  * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
180  */
181 int usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
182 		struct usb_endpoint_descriptor **bulk_in,
183 		struct usb_endpoint_descriptor **bulk_out,
184 		struct usb_endpoint_descriptor **int_in,
185 		struct usb_endpoint_descriptor **int_out)
186 {
187 	struct usb_endpoint_descriptor *epd;
188 	int i;
189 
190 	if (bulk_in)
191 		*bulk_in = NULL;
192 	if (bulk_out)
193 		*bulk_out = NULL;
194 	if (int_in)
195 		*int_in = NULL;
196 	if (int_out)
197 		*int_out = NULL;
198 
199 	for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
200 		epd = &alt->endpoint[i].desc;
201 
202 		if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
203 			return 0;
204 	}
205 
206 	return -ENXIO;
207 }
208 EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
209 
210 /**
211  * usb_find_endpoint() - Given an endpoint address, search for the endpoint's
212  * usb_host_endpoint structure in an interface's current altsetting.
213  * @intf: the interface whose current altsetting should be searched
214  * @ep_addr: the endpoint address (number and direction) to find
215  *
216  * Search the altsetting's list of endpoints for one with the specified address.
217  *
218  * Return: Pointer to the usb_host_endpoint if found, %NULL otherwise.
219  */
220 static const struct usb_host_endpoint *usb_find_endpoint(
221 		const struct usb_interface *intf, unsigned int ep_addr)
222 {
223 	int n;
224 	const struct usb_host_endpoint *ep;
225 
226 	n = intf->cur_altsetting->desc.bNumEndpoints;
227 	ep = intf->cur_altsetting->endpoint;
228 	for (; n > 0; (--n, ++ep)) {
229 		if (ep->desc.bEndpointAddress == ep_addr)
230 			return ep;
231 	}
232 	return NULL;
233 }
234 
235 /**
236  * usb_check_bulk_endpoints - Check whether an interface's current altsetting
237  * contains a set of bulk endpoints with the given addresses.
238  * @intf: the interface whose current altsetting should be searched
239  * @ep_addrs: 0-terminated array of the endpoint addresses (number and
240  * direction) to look for
241  *
242  * Search for endpoints with the specified addresses and check their types.
243  *
244  * Return: %true if all the endpoints are found and are bulk, %false otherwise.
245  */
246 bool usb_check_bulk_endpoints(
247 		const struct usb_interface *intf, const u8 *ep_addrs)
248 {
249 	const struct usb_host_endpoint *ep;
250 
251 	for (; *ep_addrs; ++ep_addrs) {
252 		ep = usb_find_endpoint(intf, *ep_addrs);
253 		if (!ep || !usb_endpoint_xfer_bulk(&ep->desc))
254 			return false;
255 	}
256 	return true;
257 }
258 EXPORT_SYMBOL_GPL(usb_check_bulk_endpoints);
259 
260 /**
261  * usb_check_int_endpoints - Check whether an interface's current altsetting
262  * contains a set of interrupt endpoints with the given addresses.
263  * @intf: the interface whose current altsetting should be searched
264  * @ep_addrs: 0-terminated array of the endpoint addresses (number and
265  * direction) to look for
266  *
267  * Search for endpoints with the specified addresses and check their types.
268  *
269  * Return: %true if all the endpoints are found and are interrupt,
270  * %false otherwise.
271  */
272 bool usb_check_int_endpoints(
273 		const struct usb_interface *intf, const u8 *ep_addrs)
274 {
275 	const struct usb_host_endpoint *ep;
276 
277 	for (; *ep_addrs; ++ep_addrs) {
278 		ep = usb_find_endpoint(intf, *ep_addrs);
279 		if (!ep || !usb_endpoint_xfer_int(&ep->desc))
280 			return false;
281 	}
282 	return true;
283 }
284 EXPORT_SYMBOL_GPL(usb_check_int_endpoints);
285 
286 /**
287  * usb_find_alt_setting() - Given a configuration, find the alternate setting
288  * for the given interface.
289  * @config: the configuration to search (not necessarily the current config).
290  * @iface_num: interface number to search in
291  * @alt_num: alternate interface setting number to search for.
292  *
293  * Search the configuration's interface cache for the given alt setting.
294  *
295  * Return: The alternate setting, if found. %NULL otherwise.
296  */
297 struct usb_host_interface *usb_find_alt_setting(
298 		struct usb_host_config *config,
299 		unsigned int iface_num,
300 		unsigned int alt_num)
301 {
302 	struct usb_interface_cache *intf_cache = NULL;
303 	int i;
304 
305 	if (!config)
306 		return NULL;
307 	for (i = 0; i < config->desc.bNumInterfaces; i++) {
308 		if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
309 				== iface_num) {
310 			intf_cache = config->intf_cache[i];
311 			break;
312 		}
313 	}
314 	if (!intf_cache)
315 		return NULL;
316 	for (i = 0; i < intf_cache->num_altsetting; i++)
317 		if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
318 			return &intf_cache->altsetting[i];
319 
320 	printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
321 			"config %u\n", alt_num, iface_num,
322 			config->desc.bConfigurationValue);
323 	return NULL;
324 }
325 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
326 
327 /**
328  * usb_ifnum_to_if - get the interface object with a given interface number
329  * @dev: the device whose current configuration is considered
330  * @ifnum: the desired interface
331  *
332  * This walks the device descriptor for the currently active configuration
333  * to find the interface object with the particular interface number.
334  *
335  * Note that configuration descriptors are not required to assign interface
336  * numbers sequentially, so that it would be incorrect to assume that
337  * the first interface in that descriptor corresponds to interface zero.
338  * This routine helps device drivers avoid such mistakes.
339  * However, you should make sure that you do the right thing with any
340  * alternate settings available for this interfaces.
341  *
342  * Don't call this function unless you are bound to one of the interfaces
343  * on this device or you have locked the device!
344  *
345  * Return: A pointer to the interface that has @ifnum as interface number,
346  * if found. %NULL otherwise.
347  */
348 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
349 				      unsigned ifnum)
350 {
351 	struct usb_host_config *config = dev->actconfig;
352 	int i;
353 
354 	if (!config)
355 		return NULL;
356 	for (i = 0; i < config->desc.bNumInterfaces; i++)
357 		if (config->interface[i]->altsetting[0]
358 				.desc.bInterfaceNumber == ifnum)
359 			return config->interface[i];
360 
361 	return NULL;
362 }
363 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
364 
365 /**
366  * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
367  * @intf: the interface containing the altsetting in question
368  * @altnum: the desired alternate setting number
369  *
370  * This searches the altsetting array of the specified interface for
371  * an entry with the correct bAlternateSetting value.
372  *
373  * Note that altsettings need not be stored sequentially by number, so
374  * it would be incorrect to assume that the first altsetting entry in
375  * the array corresponds to altsetting zero.  This routine helps device
376  * drivers avoid such mistakes.
377  *
378  * Don't call this function unless you are bound to the intf interface
379  * or you have locked the device!
380  *
381  * Return: A pointer to the entry of the altsetting array of @intf that
382  * has @altnum as the alternate setting number. %NULL if not found.
383  */
384 struct usb_host_interface *usb_altnum_to_altsetting(
385 					const struct usb_interface *intf,
386 					unsigned int altnum)
387 {
388 	int i;
389 
390 	for (i = 0; i < intf->num_altsetting; i++) {
391 		if (intf->altsetting[i].desc.bAlternateSetting == altnum)
392 			return &intf->altsetting[i];
393 	}
394 	return NULL;
395 }
396 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
397 
398 struct find_interface_arg {
399 	int minor;
400 	struct device_driver *drv;
401 };
402 
403 static int __find_interface(struct device *dev, const void *data)
404 {
405 	const struct find_interface_arg *arg = data;
406 	struct usb_interface *intf;
407 
408 	if (!is_usb_interface(dev))
409 		return 0;
410 
411 	if (dev->driver != arg->drv)
412 		return 0;
413 	intf = to_usb_interface(dev);
414 	return intf->minor == arg->minor;
415 }
416 
417 /**
418  * usb_find_interface - find usb_interface pointer for driver and device
419  * @drv: the driver whose current configuration is considered
420  * @minor: the minor number of the desired device
421  *
422  * This walks the bus device list and returns a pointer to the interface
423  * with the matching minor and driver.  Note, this only works for devices
424  * that share the USB major number.
425  *
426  * Return: A pointer to the interface with the matching major and @minor.
427  */
428 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
429 {
430 	struct find_interface_arg argb;
431 	struct device *dev;
432 
433 	argb.minor = minor;
434 	argb.drv = &drv->driver;
435 
436 	dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
437 
438 	/* Drop reference count from bus_find_device */
439 	put_device(dev);
440 
441 	return dev ? to_usb_interface(dev) : NULL;
442 }
443 EXPORT_SYMBOL_GPL(usb_find_interface);
444 
445 struct each_dev_arg {
446 	void *data;
447 	int (*fn)(struct usb_device *, void *);
448 };
449 
450 static int __each_dev(struct device *dev, void *data)
451 {
452 	struct each_dev_arg *arg = (struct each_dev_arg *)data;
453 
454 	/* There are struct usb_interface on the same bus, filter them out */
455 	if (!is_usb_device(dev))
456 		return 0;
457 
458 	return arg->fn(to_usb_device(dev), arg->data);
459 }
460 
461 /**
462  * usb_for_each_dev - iterate over all USB devices in the system
463  * @data: data pointer that will be handed to the callback function
464  * @fn: callback function to be called for each USB device
465  *
466  * Iterate over all USB devices and call @fn for each, passing it @data. If it
467  * returns anything other than 0, we break the iteration prematurely and return
468  * that value.
469  */
470 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
471 {
472 	struct each_dev_arg arg = {data, fn};
473 
474 	return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
475 }
476 EXPORT_SYMBOL_GPL(usb_for_each_dev);
477 
478 /**
479  * usb_release_dev - free a usb device structure when all users of it are finished.
480  * @dev: device that's been disconnected
481  *
482  * Will be called only by the device core when all users of this usb device are
483  * done.
484  */
485 static void usb_release_dev(struct device *dev)
486 {
487 	struct usb_device *udev;
488 	struct usb_hcd *hcd;
489 
490 	udev = to_usb_device(dev);
491 	hcd = bus_to_hcd(udev->bus);
492 
493 	usb_destroy_configuration(udev);
494 	usb_release_bos_descriptor(udev);
495 	of_node_put(dev->of_node);
496 	usb_put_hcd(hcd);
497 	kfree(udev->product);
498 	kfree(udev->manufacturer);
499 	kfree(udev->serial);
500 	kfree(udev);
501 }
502 
503 static int usb_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
504 {
505 	const struct usb_device *usb_dev;
506 
507 	usb_dev = to_usb_device(dev);
508 
509 	if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
510 		return -ENOMEM;
511 
512 	if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
513 		return -ENOMEM;
514 
515 	return 0;
516 }
517 
518 #ifdef	CONFIG_PM
519 
520 /* USB device Power-Management thunks.
521  * There's no need to distinguish here between quiescing a USB device
522  * and powering it down; the generic_suspend() routine takes care of
523  * it by skipping the usb_port_suspend() call for a quiesce.  And for
524  * USB interfaces there's no difference at all.
525  */
526 
527 static int usb_dev_prepare(struct device *dev)
528 {
529 	return 0;		/* Implement eventually? */
530 }
531 
532 static void usb_dev_complete(struct device *dev)
533 {
534 	/* Currently used only for rebinding interfaces */
535 	usb_resume_complete(dev);
536 }
537 
538 static int usb_dev_suspend(struct device *dev)
539 {
540 	return usb_suspend(dev, PMSG_SUSPEND);
541 }
542 
543 static int usb_dev_resume(struct device *dev)
544 {
545 	return usb_resume(dev, PMSG_RESUME);
546 }
547 
548 static int usb_dev_freeze(struct device *dev)
549 {
550 	return usb_suspend(dev, PMSG_FREEZE);
551 }
552 
553 static int usb_dev_thaw(struct device *dev)
554 {
555 	return usb_resume(dev, PMSG_THAW);
556 }
557 
558 static int usb_dev_poweroff(struct device *dev)
559 {
560 	return usb_suspend(dev, PMSG_HIBERNATE);
561 }
562 
563 static int usb_dev_restore(struct device *dev)
564 {
565 	return usb_resume(dev, PMSG_RESTORE);
566 }
567 
568 static const struct dev_pm_ops usb_device_pm_ops = {
569 	.prepare =	usb_dev_prepare,
570 	.complete =	usb_dev_complete,
571 	.suspend =	usb_dev_suspend,
572 	.resume =	usb_dev_resume,
573 	.freeze =	usb_dev_freeze,
574 	.thaw =		usb_dev_thaw,
575 	.poweroff =	usb_dev_poweroff,
576 	.restore =	usb_dev_restore,
577 	.runtime_suspend =	usb_runtime_suspend,
578 	.runtime_resume =	usb_runtime_resume,
579 	.runtime_idle =		usb_runtime_idle,
580 };
581 
582 #endif	/* CONFIG_PM */
583 
584 
585 static char *usb_devnode(const struct device *dev,
586 			 umode_t *mode, kuid_t *uid, kgid_t *gid)
587 {
588 	const struct usb_device *usb_dev;
589 
590 	usb_dev = to_usb_device(dev);
591 	return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
592 			 usb_dev->bus->busnum, usb_dev->devnum);
593 }
594 
595 const struct device_type usb_device_type = {
596 	.name =		"usb_device",
597 	.release =	usb_release_dev,
598 	.uevent =	usb_dev_uevent,
599 	.devnode = 	usb_devnode,
600 #ifdef CONFIG_PM
601 	.pm =		&usb_device_pm_ops,
602 #endif
603 };
604 
605 static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd)
606 {
607 	struct usb_hub *hub;
608 
609 	if (!dev->parent)
610 		return true; /* Root hub always ok [and always wired] */
611 
612 	switch (hcd->dev_policy) {
613 	case USB_DEVICE_AUTHORIZE_NONE:
614 	default:
615 		return false;
616 
617 	case USB_DEVICE_AUTHORIZE_ALL:
618 		return true;
619 
620 	case USB_DEVICE_AUTHORIZE_INTERNAL:
621 		hub = usb_hub_to_struct_hub(dev->parent);
622 		return hub->ports[dev->portnum - 1]->connect_type ==
623 				USB_PORT_CONNECT_TYPE_HARD_WIRED;
624 	}
625 }
626 
627 /**
628  * usb_alloc_dev - usb device constructor (usbcore-internal)
629  * @parent: hub to which device is connected; null to allocate a root hub
630  * @bus: bus used to access the device
631  * @port1: one-based index of port; ignored for root hubs
632  *
633  * Context: task context, might sleep.
634  *
635  * Only hub drivers (including virtual root hub drivers for host
636  * controllers) should ever call this.
637  *
638  * This call may not be used in a non-sleeping context.
639  *
640  * Return: On success, a pointer to the allocated usb device. %NULL on
641  * failure.
642  */
643 struct usb_device *usb_alloc_dev(struct usb_device *parent,
644 				 struct usb_bus *bus, unsigned port1)
645 {
646 	struct usb_device *dev;
647 	struct usb_hcd *usb_hcd = bus_to_hcd(bus);
648 	unsigned raw_port = port1;
649 
650 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
651 	if (!dev)
652 		return NULL;
653 
654 	if (!usb_get_hcd(usb_hcd)) {
655 		kfree(dev);
656 		return NULL;
657 	}
658 	/* Root hubs aren't true devices, so don't allocate HCD resources */
659 	if (usb_hcd->driver->alloc_dev && parent &&
660 		!usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
661 		usb_put_hcd(bus_to_hcd(bus));
662 		kfree(dev);
663 		return NULL;
664 	}
665 
666 	device_initialize(&dev->dev);
667 	dev->dev.bus = &usb_bus_type;
668 	dev->dev.type = &usb_device_type;
669 	dev->dev.groups = usb_device_groups;
670 	set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
671 	dev->state = USB_STATE_ATTACHED;
672 	dev->lpm_disable_count = 1;
673 	dev->offload_usage = 0;
674 	atomic_set(&dev->urbnum, 0);
675 
676 	INIT_LIST_HEAD(&dev->ep0.urb_list);
677 	dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
678 	dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
679 	/* ep0 maxpacket comes later, from device descriptor */
680 	usb_enable_endpoint(dev, &dev->ep0, false);
681 	dev->can_submit = 1;
682 
683 	/* Save readable and stable topology id, distinguishing devices
684 	 * by location for diagnostics, tools, driver model, etc.  The
685 	 * string is a path along hub ports, from the root.  Each device's
686 	 * dev->devpath will be stable until USB is re-cabled, and hubs
687 	 * are often labeled with these port numbers.  The name isn't
688 	 * as stable:  bus->busnum changes easily from modprobe order,
689 	 * cardbus or pci hotplugging, and so on.
690 	 */
691 	if (unlikely(!parent)) {
692 		dev->devpath[0] = '0';
693 		dev->route = 0;
694 
695 		dev->dev.parent = bus->controller;
696 		device_set_of_node_from_dev(&dev->dev, bus->sysdev);
697 		dev_set_name(&dev->dev, "usb%d", bus->busnum);
698 	} else {
699 		int n;
700 
701 		/* match any labeling on the hubs; it's one-based */
702 		if (parent->devpath[0] == '0') {
703 			n = snprintf(dev->devpath, sizeof(dev->devpath), "%d", port1);
704 			/* Root ports are not counted in route string */
705 			dev->route = 0;
706 		} else {
707 			n = snprintf(dev->devpath, sizeof(dev->devpath), "%s.%d",
708 				     parent->devpath, port1);
709 			/* Route string assumes hubs have less than 16 ports */
710 			if (port1 < 15)
711 				dev->route = parent->route +
712 					(port1 << ((parent->level - 1)*4));
713 			else
714 				dev->route = parent->route +
715 					(15 << ((parent->level - 1)*4));
716 		}
717 		if (n >= sizeof(dev->devpath)) {
718 			usb_put_hcd(bus_to_hcd(bus));
719 			usb_put_dev(dev);
720 			return NULL;
721 		}
722 
723 		dev->dev.parent = &parent->dev;
724 		dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
725 
726 		if (!parent->parent) {
727 			/* device under root hub's port */
728 			raw_port = usb_hcd_find_raw_port_number(usb_hcd,
729 				port1);
730 		}
731 		dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
732 
733 		/* hub driver sets up TT records */
734 	}
735 
736 	dev->portnum = port1;
737 	dev->bus = bus;
738 	dev->parent = parent;
739 	INIT_LIST_HEAD(&dev->filelist);
740 
741 #ifdef	CONFIG_PM
742 	pm_runtime_set_autosuspend_delay(&dev->dev,
743 			usb_autosuspend_delay * 1000);
744 	dev->connect_time = jiffies;
745 	dev->active_duration = -jiffies;
746 #endif
747 
748 	dev->authorized = usb_dev_authorized(dev, usb_hcd);
749 	return dev;
750 }
751 EXPORT_SYMBOL_GPL(usb_alloc_dev);
752 
753 /**
754  * usb_get_dev - increments the reference count of the usb device structure
755  * @dev: the device being referenced
756  *
757  * Each live reference to a device should be refcounted.
758  *
759  * Drivers for USB interfaces should normally record such references in
760  * their probe() methods, when they bind to an interface, and release
761  * them by calling usb_put_dev(), in their disconnect() methods.
762  * However, if a driver does not access the usb_device structure after
763  * its disconnect() method returns then refcounting is not necessary,
764  * because the USB core guarantees that a usb_device will not be
765  * deallocated until after all of its interface drivers have been unbound.
766  *
767  * Return: A pointer to the device with the incremented reference counter.
768  */
769 struct usb_device *usb_get_dev(struct usb_device *dev)
770 {
771 	if (dev)
772 		get_device(&dev->dev);
773 	return dev;
774 }
775 EXPORT_SYMBOL_GPL(usb_get_dev);
776 
777 /**
778  * usb_put_dev - release a use of the usb device structure
779  * @dev: device that's been disconnected
780  *
781  * Must be called when a user of a device is finished with it.  When the last
782  * user of the device calls this function, the memory of the device is freed.
783  */
784 void usb_put_dev(struct usb_device *dev)
785 {
786 	if (dev)
787 		put_device(&dev->dev);
788 }
789 EXPORT_SYMBOL_GPL(usb_put_dev);
790 
791 /**
792  * usb_get_intf - increments the reference count of the usb interface structure
793  * @intf: the interface being referenced
794  *
795  * Each live reference to a interface must be refcounted.
796  *
797  * Drivers for USB interfaces should normally record such references in
798  * their probe() methods, when they bind to an interface, and release
799  * them by calling usb_put_intf(), in their disconnect() methods.
800  * However, if a driver does not access the usb_interface structure after
801  * its disconnect() method returns then refcounting is not necessary,
802  * because the USB core guarantees that a usb_interface will not be
803  * deallocated until after its driver has been unbound.
804  *
805  * Return: A pointer to the interface with the incremented reference counter.
806  */
807 struct usb_interface *usb_get_intf(struct usb_interface *intf)
808 {
809 	if (intf)
810 		get_device(&intf->dev);
811 	return intf;
812 }
813 EXPORT_SYMBOL_GPL(usb_get_intf);
814 
815 /**
816  * usb_put_intf - release a use of the usb interface structure
817  * @intf: interface that's been decremented
818  *
819  * Must be called when a user of an interface is finished with it.  When the
820  * last user of the interface calls this function, the memory of the interface
821  * is freed.
822  */
823 void usb_put_intf(struct usb_interface *intf)
824 {
825 	if (intf)
826 		put_device(&intf->dev);
827 }
828 EXPORT_SYMBOL_GPL(usb_put_intf);
829 
830 /**
831  * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint
832  * @intf: the usb interface
833  *
834  * While a USB device cannot perform DMA operations by itself, many USB
835  * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint
836  * for the given USB interface, if any. The returned device structure must be
837  * released with put_device().
838  *
839  * See also usb_get_dma_device().
840  *
841  * Returns: A reference to the usb interface's DMA endpoint; or NULL if none
842  *          exists.
843  */
844 struct device *usb_intf_get_dma_device(struct usb_interface *intf)
845 {
846 	struct usb_device *udev = interface_to_usbdev(intf);
847 	struct device *dmadev;
848 
849 	if (!udev->bus)
850 		return NULL;
851 
852 	dmadev = get_device(udev->bus->sysdev);
853 	if (!dmadev || !dmadev->dma_mask) {
854 		put_device(dmadev);
855 		return NULL;
856 	}
857 
858 	return dmadev;
859 }
860 EXPORT_SYMBOL_GPL(usb_intf_get_dma_device);
861 
862 /*			USB device locking
863  *
864  * USB devices and interfaces are locked using the semaphore in their
865  * embedded struct device.  The hub driver guarantees that whenever a
866  * device is connected or disconnected, drivers are called with the
867  * USB device locked as well as their particular interface.
868  *
869  * Complications arise when several devices are to be locked at the same
870  * time.  Only hub-aware drivers that are part of usbcore ever have to
871  * do this; nobody else needs to worry about it.  The rule for locking
872  * is simple:
873  *
874  *	When locking both a device and its parent, always lock the
875  *	parent first.
876  */
877 
878 /**
879  * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
880  * @udev: device that's being locked
881  * @iface: interface bound to the driver making the request (optional)
882  *
883  * Attempts to acquire the device lock, but fails if the device is
884  * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
885  * is neither BINDING nor BOUND.  Rather than sleeping to wait for the
886  * lock, the routine polls repeatedly.  This is to prevent deadlock with
887  * disconnect; in some drivers (such as usb-storage) the disconnect()
888  * or suspend() method will block waiting for a device reset to complete.
889  *
890  * Return: A negative error code for failure, otherwise 0.
891  */
892 int usb_lock_device_for_reset(struct usb_device *udev,
893 			      const struct usb_interface *iface)
894 {
895 	unsigned long jiffies_expire = jiffies + HZ;
896 
897 	if (udev->state == USB_STATE_NOTATTACHED)
898 		return -ENODEV;
899 	if (udev->state == USB_STATE_SUSPENDED)
900 		return -EHOSTUNREACH;
901 	if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
902 			iface->condition == USB_INTERFACE_UNBOUND))
903 		return -EINTR;
904 
905 	while (!usb_trylock_device(udev)) {
906 
907 		/* If we can't acquire the lock after waiting one second,
908 		 * we're probably deadlocked */
909 		if (time_after(jiffies, jiffies_expire))
910 			return -EBUSY;
911 
912 		msleep(15);
913 		if (udev->state == USB_STATE_NOTATTACHED)
914 			return -ENODEV;
915 		if (udev->state == USB_STATE_SUSPENDED)
916 			return -EHOSTUNREACH;
917 		if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
918 				iface->condition == USB_INTERFACE_UNBOUND))
919 			return -EINTR;
920 	}
921 	return 0;
922 }
923 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
924 
925 /**
926  * usb_get_current_frame_number - return current bus frame number
927  * @dev: the device whose bus is being queried
928  *
929  * Return: The current frame number for the USB host controller used
930  * with the given USB device. This can be used when scheduling
931  * isochronous requests.
932  *
933  * Note: Different kinds of host controller have different "scheduling
934  * horizons". While one type might support scheduling only 32 frames
935  * into the future, others could support scheduling up to 1024 frames
936  * into the future.
937  *
938  */
939 int usb_get_current_frame_number(struct usb_device *dev)
940 {
941 	return usb_hcd_get_frame_number(dev);
942 }
943 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
944 
945 /*-------------------------------------------------------------------*/
946 /*
947  * __usb_get_extra_descriptor() finds a descriptor of specific type in the
948  * extra field of the interface and endpoint descriptor structs.
949  */
950 
951 int __usb_get_extra_descriptor(char *buffer, unsigned size,
952 			       unsigned char type, void **ptr, size_t minsize)
953 {
954 	struct usb_descriptor_header *header;
955 
956 	while (size >= sizeof(struct usb_descriptor_header)) {
957 		header = (struct usb_descriptor_header *)buffer;
958 
959 		if (header->bLength < 2 || header->bLength > size) {
960 			printk(KERN_ERR
961 				"%s: bogus descriptor, type %d length %d\n",
962 				usbcore_name,
963 				header->bDescriptorType,
964 				header->bLength);
965 			return -1;
966 		}
967 
968 		if (header->bDescriptorType == type && header->bLength >= minsize) {
969 			*ptr = header;
970 			return 0;
971 		}
972 
973 		buffer += header->bLength;
974 		size -= header->bLength;
975 	}
976 	return -1;
977 }
978 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
979 
980 /**
981  * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
982  * @dev: device the buffer will be used with
983  * @size: requested buffer size
984  * @mem_flags: affect whether allocation may block
985  * @dma: used to return DMA address of buffer
986  *
987  * Return: Either null (indicating no buffer could be allocated), or the
988  * cpu-space pointer to a buffer that may be used to perform DMA to the
989  * specified device.  Such cpu-space buffers are returned along with the DMA
990  * address (through the pointer provided).
991  *
992  * Note:
993  * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
994  * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
995  * hardware during URB completion/resubmit.  The implementation varies between
996  * platforms, depending on details of how DMA will work to this device.
997  * Using these buffers also eliminates cacheline sharing problems on
998  * architectures where CPU caches are not DMA-coherent.  On systems without
999  * bus-snooping caches, these buffers are uncached.
1000  *
1001  * When the buffer is no longer used, free it with usb_free_coherent().
1002  */
1003 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
1004 			 dma_addr_t *dma)
1005 {
1006 	if (!dev || !dev->bus)
1007 		return NULL;
1008 	return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
1009 }
1010 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
1011 
1012 /**
1013  * usb_free_coherent - free memory allocated with usb_alloc_coherent()
1014  * @dev: device the buffer was used with
1015  * @size: requested buffer size
1016  * @addr: CPU address of buffer
1017  * @dma: DMA address of buffer
1018  *
1019  * This reclaims an I/O buffer, letting it be reused.  The memory must have
1020  * been allocated using usb_alloc_coherent(), and the parameters must match
1021  * those provided in that allocation request.
1022  */
1023 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
1024 		       dma_addr_t dma)
1025 {
1026 	if (!dev || !dev->bus)
1027 		return;
1028 	if (!addr)
1029 		return;
1030 	hcd_buffer_free(dev->bus, size, addr, dma);
1031 }
1032 EXPORT_SYMBOL_GPL(usb_free_coherent);
1033 
1034 /**
1035  * usb_alloc_noncoherent - allocate dma-noncoherent buffer for URB_NO_xxx_DMA_MAP
1036  * @dev: device the buffer will be used with
1037  * @size: requested buffer size
1038  * @mem_flags: affect whether allocation may block
1039  * @dma: used to return DMA address of buffer
1040  * @dir: DMA transfer direction
1041  * @table: used to return sg_table of allocated memory
1042  *
1043  * To explicit manage the memory ownership for the kernel vs the device by
1044  * USB core, the user needs save sg_table to urb->sgt. Then USB core will
1045  * do DMA sync for CPU and device properly.
1046  *
1047  * When the buffer is no longer used, free it with usb_free_noncoherent().
1048  *
1049  * Return: Either null (indicating no buffer could be allocated), or the
1050  * cpu-space pointer to a buffer that may be used to perform DMA to the
1051  * specified device.  Such cpu-space buffers are returned along with the DMA
1052  * address (through the pointer provided).
1053  */
1054 void *usb_alloc_noncoherent(struct usb_device *dev, size_t size,
1055 			    gfp_t mem_flags, dma_addr_t *dma,
1056 			    enum dma_data_direction dir,
1057 			    struct sg_table **table)
1058 {
1059 	struct device *dmadev;
1060 	struct sg_table *sgt;
1061 	void *buffer;
1062 
1063 	if (!dev || !dev->bus)
1064 		return NULL;
1065 
1066 	dmadev = bus_to_hcd(dev->bus)->self.sysdev;
1067 
1068 	sgt = dma_alloc_noncontiguous(dmadev, size, dir, mem_flags, 0);
1069 	if (!sgt)
1070 		return NULL;
1071 
1072 	buffer = dma_vmap_noncontiguous(dmadev, size, sgt);
1073 	if (!buffer) {
1074 		dma_free_noncontiguous(dmadev, size, sgt, dir);
1075 		return NULL;
1076 	}
1077 
1078 	*table = sgt;
1079 	*dma = sg_dma_address(sgt->sgl);
1080 
1081 	return buffer;
1082 }
1083 EXPORT_SYMBOL_GPL(usb_alloc_noncoherent);
1084 
1085 /**
1086  * usb_free_noncoherent - free memory allocated with usb_alloc_noncoherent()
1087  * @dev: device the buffer was used with
1088  * @size: requested buffer size
1089  * @addr: CPU address of buffer
1090  * @dir: DMA transfer direction
1091  * @table: describe the allocated and DMA mapped memory,
1092  *
1093  * This reclaims an I/O buffer, letting it be reused.  The memory must have
1094  * been allocated using usb_alloc_noncoherent(), and the parameters must match
1095  * those provided in that allocation request.
1096  */
1097 void usb_free_noncoherent(struct usb_device *dev, size_t size,
1098 			  void *addr, enum dma_data_direction dir,
1099 			  struct sg_table *table)
1100 {
1101 	struct device *dmadev;
1102 
1103 	if (!dev || !dev->bus)
1104 		return;
1105 	if (!addr)
1106 		return;
1107 
1108 	dmadev = bus_to_hcd(dev->bus)->self.sysdev;
1109 	dma_vunmap_noncontiguous(dmadev, addr);
1110 	dma_free_noncontiguous(dmadev, size, table, dir);
1111 }
1112 EXPORT_SYMBOL_GPL(usb_free_noncoherent);
1113 
1114 /**
1115  * usb_endpoint_max_periodic_payload - Get maximum payload bytes per service
1116  *				       interval
1117  * @udev: The USB device
1118  * @ep: The endpoint
1119  *
1120  * Returns: the maximum number of bytes isochronous or interrupt endpoint @ep
1121  * can transfer during a service interval, or 0 for other endpoints.
1122  */
1123 u32 usb_endpoint_max_periodic_payload(struct usb_device *udev,
1124 				      const struct usb_host_endpoint *ep)
1125 {
1126 	if (!usb_endpoint_xfer_isoc(&ep->desc) &&
1127 	    !usb_endpoint_xfer_int(&ep->desc))
1128 		return 0;
1129 
1130 	switch (udev->speed) {
1131 	case USB_SPEED_SUPER_PLUS:
1132 		if (USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes))
1133 			return le32_to_cpu(ep->ssp_isoc_ep_comp.dwBytesPerInterval);
1134 		fallthrough;
1135 	case USB_SPEED_SUPER:
1136 		return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval);
1137 	default:
1138 		if (usb_endpoint_is_hs_isoc_double(udev, ep))
1139 			return le32_to_cpu(ep->eusb2_isoc_ep_comp.dwBytesPerInterval);
1140 		return usb_endpoint_maxp(&ep->desc) * usb_endpoint_maxp_mult(&ep->desc);
1141 	}
1142 }
1143 EXPORT_SYMBOL_GPL(usb_endpoint_max_periodic_payload);
1144 
1145 /**
1146  * usb_endpoint_is_hs_isoc_double - Tell whether an endpoint uses USB 2
1147  *                                  Isochronous Double IN Bandwidth
1148  * @udev: The USB device
1149  * @ep: The endpoint
1150  *
1151  * Returns: true if an endpoint @ep conforms to USB 2 Isochronous Double IN
1152  * Bandwidth ECN, false otherwise.
1153  */
1154 bool usb_endpoint_is_hs_isoc_double(struct usb_device *udev,
1155 				    const struct usb_host_endpoint *ep)
1156 {
1157 	return ep->eusb2_isoc_ep_comp.bDescriptorType &&
1158 		le16_to_cpu(udev->descriptor.bcdUSB) == 0x220 &&
1159 		usb_endpoint_is_isoc_in(&ep->desc) &&
1160 		!le16_to_cpu(ep->desc.wMaxPacketSize);
1161 }
1162 EXPORT_SYMBOL_GPL(usb_endpoint_is_hs_isoc_double);
1163 
1164 /*
1165  * Notifications of device and interface registration
1166  */
1167 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
1168 		void *data)
1169 {
1170 	struct device *dev = data;
1171 
1172 	switch (action) {
1173 	case BUS_NOTIFY_ADD_DEVICE:
1174 		if (dev->type == &usb_device_type)
1175 			(void) usb_create_sysfs_dev_files(to_usb_device(dev));
1176 		else if (dev->type == &usb_if_device_type)
1177 			usb_create_sysfs_intf_files(to_usb_interface(dev));
1178 		break;
1179 
1180 	case BUS_NOTIFY_DEL_DEVICE:
1181 		if (dev->type == &usb_device_type)
1182 			usb_remove_sysfs_dev_files(to_usb_device(dev));
1183 		else if (dev->type == &usb_if_device_type)
1184 			usb_remove_sysfs_intf_files(to_usb_interface(dev));
1185 		break;
1186 	}
1187 	return 0;
1188 }
1189 
1190 static struct notifier_block usb_bus_nb = {
1191 	.notifier_call = usb_bus_notify,
1192 };
1193 
1194 static void usb_debugfs_init(void)
1195 {
1196 	debugfs_create_file("devices", 0444, usb_debug_root, NULL,
1197 			    &usbfs_devices_fops);
1198 }
1199 
1200 static void usb_debugfs_cleanup(void)
1201 {
1202 	debugfs_lookup_and_remove("devices", usb_debug_root);
1203 }
1204 
1205 /*
1206  * Init
1207  */
1208 static int __init usb_init(void)
1209 {
1210 	int retval;
1211 	if (usb_disabled()) {
1212 		pr_info("%s: USB support disabled\n", usbcore_name);
1213 		return 0;
1214 	}
1215 	usb_init_pool_max();
1216 
1217 	usb_debugfs_init();
1218 
1219 	usb_acpi_register();
1220 	retval = bus_register(&usb_bus_type);
1221 	if (retval)
1222 		goto bus_register_failed;
1223 	retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1224 	if (retval)
1225 		goto bus_notifier_failed;
1226 	retval = usb_major_init();
1227 	if (retval)
1228 		goto major_init_failed;
1229 	retval = class_register(&usbmisc_class);
1230 	if (retval)
1231 		goto class_register_failed;
1232 	retval = usb_register(&usbfs_driver);
1233 	if (retval)
1234 		goto driver_register_failed;
1235 	retval = usb_devio_init();
1236 	if (retval)
1237 		goto usb_devio_init_failed;
1238 	retval = usb_hub_init();
1239 	if (retval)
1240 		goto hub_init_failed;
1241 	retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1242 	if (!retval)
1243 		goto out;
1244 
1245 	usb_hub_cleanup();
1246 hub_init_failed:
1247 	usb_devio_cleanup();
1248 usb_devio_init_failed:
1249 	usb_deregister(&usbfs_driver);
1250 driver_register_failed:
1251 	class_unregister(&usbmisc_class);
1252 class_register_failed:
1253 	usb_major_cleanup();
1254 major_init_failed:
1255 	bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1256 bus_notifier_failed:
1257 	bus_unregister(&usb_bus_type);
1258 bus_register_failed:
1259 	usb_acpi_unregister();
1260 	usb_debugfs_cleanup();
1261 out:
1262 	return retval;
1263 }
1264 
1265 /*
1266  * Cleanup
1267  */
1268 static void __exit usb_exit(void)
1269 {
1270 	/* This will matter if shutdown/reboot does exitcalls. */
1271 	if (usb_disabled())
1272 		return;
1273 
1274 	usb_release_quirk_list();
1275 	usb_deregister_device_driver(&usb_generic_driver);
1276 	usb_major_cleanup();
1277 	usb_deregister(&usbfs_driver);
1278 	usb_devio_cleanup();
1279 	usb_hub_cleanup();
1280 	class_unregister(&usbmisc_class);
1281 	bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1282 	bus_unregister(&usb_bus_type);
1283 	usb_acpi_unregister();
1284 	usb_debugfs_cleanup();
1285 	idr_destroy(&usb_bus_idr);
1286 }
1287 
1288 subsys_initcall(usb_init);
1289 module_exit(usb_exit);
1290 MODULE_DESCRIPTION("USB core host-side support");
1291 MODULE_LICENSE("GPL");
1292