xref: /openbmc/u-boot/drivers/usb/host/usb-uclass.c (revision 29b103c7)
1 /*
2  * (C) Copyright 2015 Google, Inc
3  * Written by Simon Glass <sjg@chromium.org>
4  *
5  * usb_match_device() modified from Linux kernel v4.0.
6  *
7  * SPDX-License-Identifier:	GPL-2.0+
8  */
9 
10 #include <common.h>
11 #include <dm.h>
12 #include <errno.h>
13 #include <usb.h>
14 #include <dm/device-internal.h>
15 #include <dm/lists.h>
16 #include <dm/root.h>
17 #include <dm/uclass-internal.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 extern bool usb_started; /* flag for the started/stopped USB status */
22 static bool asynch_allowed;
23 
24 struct usb_uclass_priv {
25 	int companion_device_count;
26 };
27 
28 int usb_disable_asynch(int disable)
29 {
30 	int old_value = asynch_allowed;
31 
32 	asynch_allowed = !disable;
33 	return old_value;
34 }
35 
36 int submit_int_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
37 		   int length, int interval)
38 {
39 	struct udevice *bus = udev->controller_dev;
40 	struct dm_usb_ops *ops = usb_get_ops(bus);
41 
42 	if (!ops->interrupt)
43 		return -ENOSYS;
44 
45 	return ops->interrupt(bus, udev, pipe, buffer, length, interval);
46 }
47 
48 int submit_control_msg(struct usb_device *udev, unsigned long pipe,
49 		       void *buffer, int length, struct devrequest *setup)
50 {
51 	struct udevice *bus = udev->controller_dev;
52 	struct dm_usb_ops *ops = usb_get_ops(bus);
53 	struct usb_uclass_priv *uc_priv = bus->uclass->priv;
54 	int err;
55 
56 	if (!ops->control)
57 		return -ENOSYS;
58 
59 	err = ops->control(bus, udev, pipe, buffer, length, setup);
60 	if (setup->request == USB_REQ_SET_FEATURE &&
61 	    setup->requesttype == USB_RT_PORT &&
62 	    setup->value == cpu_to_le16(USB_PORT_FEAT_RESET) &&
63 	    err == -ENXIO) {
64 		/* Device handed over to companion after port reset */
65 		uc_priv->companion_device_count++;
66 	}
67 
68 	return err;
69 }
70 
71 int submit_bulk_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
72 		    int length)
73 {
74 	struct udevice *bus = udev->controller_dev;
75 	struct dm_usb_ops *ops = usb_get_ops(bus);
76 
77 	if (!ops->bulk)
78 		return -ENOSYS;
79 
80 	return ops->bulk(bus, udev, pipe, buffer, length);
81 }
82 
83 struct int_queue *create_int_queue(struct usb_device *udev,
84 		unsigned long pipe, int queuesize, int elementsize,
85 		void *buffer, int interval)
86 {
87 	struct udevice *bus = udev->controller_dev;
88 	struct dm_usb_ops *ops = usb_get_ops(bus);
89 
90 	if (!ops->create_int_queue)
91 		return NULL;
92 
93 	return ops->create_int_queue(bus, udev, pipe, queuesize, elementsize,
94 				     buffer, interval);
95 }
96 
97 void *poll_int_queue(struct usb_device *udev, struct int_queue *queue)
98 {
99 	struct udevice *bus = udev->controller_dev;
100 	struct dm_usb_ops *ops = usb_get_ops(bus);
101 
102 	if (!ops->poll_int_queue)
103 		return NULL;
104 
105 	return ops->poll_int_queue(bus, udev, queue);
106 }
107 
108 int destroy_int_queue(struct usb_device *udev, struct int_queue *queue)
109 {
110 	struct udevice *bus = udev->controller_dev;
111 	struct dm_usb_ops *ops = usb_get_ops(bus);
112 
113 	if (!ops->destroy_int_queue)
114 		return -ENOSYS;
115 
116 	return ops->destroy_int_queue(bus, udev, queue);
117 }
118 
119 int usb_alloc_device(struct usb_device *udev)
120 {
121 	struct udevice *bus = udev->controller_dev;
122 	struct dm_usb_ops *ops = usb_get_ops(bus);
123 
124 	/* This is only requird by some controllers - current XHCI */
125 	if (!ops->alloc_device)
126 		return 0;
127 
128 	return ops->alloc_device(bus, udev);
129 }
130 
131 int usb_stop(void)
132 {
133 	struct udevice *bus;
134 	struct uclass *uc;
135 	struct usb_uclass_priv *uc_priv;
136 	int err = 0, ret;
137 
138 	/* De-activate any devices that have been activated */
139 	ret = uclass_get(UCLASS_USB, &uc);
140 	if (ret)
141 		return ret;
142 
143 	uc_priv = uc->priv;
144 
145 	uclass_foreach_dev(bus, uc) {
146 		ret = device_remove(bus);
147 		if (ret && !err)
148 			err = ret;
149 	}
150 
151 #ifdef CONFIG_SANDBOX
152 	struct udevice *dev;
153 
154 	/* Reset all enulation devices */
155 	ret = uclass_get(UCLASS_USB_EMUL, &uc);
156 	if (ret)
157 		return ret;
158 
159 	uclass_foreach_dev(dev, uc)
160 		usb_emul_reset(dev);
161 #endif
162 	usb_stor_reset();
163 	usb_hub_reset();
164 	uc_priv->companion_device_count = 0;
165 	usb_started = 0;
166 
167 	return err;
168 }
169 
170 static void usb_scan_bus(struct udevice *bus, bool recurse)
171 {
172 	struct usb_bus_priv *priv;
173 	struct udevice *dev;
174 	int ret;
175 
176 	priv = dev_get_uclass_priv(bus);
177 
178 	assert(recurse);	/* TODO: Support non-recusive */
179 
180 	printf("scanning bus %d for devices... ", bus->seq);
181 	debug("\n");
182 	ret = usb_scan_device(bus, 0, USB_SPEED_FULL, &dev);
183 	if (ret)
184 		printf("failed, error %d\n", ret);
185 	else if (priv->next_addr == 0)
186 		printf("No USB Device found\n");
187 	else
188 		printf("%d USB Device(s) found\n", priv->next_addr);
189 }
190 
191 int usb_init(void)
192 {
193 	int controllers_initialized = 0;
194 	struct usb_uclass_priv *uc_priv;
195 	struct usb_bus_priv *priv;
196 	struct udevice *bus;
197 	struct uclass *uc;
198 	int count = 0;
199 	int ret;
200 
201 	asynch_allowed = 1;
202 	usb_hub_reset();
203 
204 	ret = uclass_get(UCLASS_USB, &uc);
205 	if (ret)
206 		return ret;
207 
208 	uc_priv = uc->priv;
209 
210 	uclass_foreach_dev(bus, uc) {
211 		/* init low_level USB */
212 		printf("USB%d:   ", count);
213 		count++;
214 		ret = device_probe(bus);
215 		if (ret == -ENODEV) {	/* No such device. */
216 			puts("Port not available.\n");
217 			controllers_initialized++;
218 			continue;
219 		}
220 
221 		if (ret) {		/* Other error. */
222 			printf("probe failed, error %d\n", ret);
223 			continue;
224 		}
225 		controllers_initialized++;
226 		usb_started = true;
227 	}
228 
229 	/*
230 	 * lowlevel init done, now scan the bus for devices i.e. search HUBs
231 	 * and configure them, first scan primary controllers.
232 	 */
233 	uclass_foreach_dev(bus, uc) {
234 		if (!device_active(bus))
235 			continue;
236 
237 		priv = dev_get_uclass_priv(bus);
238 		if (!priv->companion)
239 			usb_scan_bus(bus, true);
240 	}
241 
242 	/*
243 	 * Now that the primary controllers have been scanned and have handed
244 	 * over any devices they do not understand to their companions, scan
245 	 * the companions if necessary.
246 	 */
247 	if (uc_priv->companion_device_count) {
248 		uclass_foreach_dev(bus, uc) {
249 			if (!device_active(bus))
250 				continue;
251 
252 			priv = dev_get_uclass_priv(bus);
253 			if (priv->companion)
254 				usb_scan_bus(bus, true);
255 		}
256 	}
257 
258 	debug("scan end\n");
259 	/* if we were not able to find at least one working bus, bail out */
260 	if (!count)
261 		printf("No controllers found\n");
262 	else if (controllers_initialized == 0)
263 		printf("USB error: all controllers failed lowlevel init\n");
264 
265 	return usb_started ? 0 : -1;
266 }
267 
268 int usb_reset_root_port(void)
269 {
270 	return -ENOSYS;
271 }
272 
273 static struct usb_device *find_child_devnum(struct udevice *parent, int devnum)
274 {
275 	struct usb_device *udev;
276 	struct udevice *dev;
277 
278 	if (!device_active(parent))
279 		return NULL;
280 	udev = dev_get_parentdata(parent);
281 	if (udev->devnum == devnum)
282 		return udev;
283 
284 	for (device_find_first_child(parent, &dev);
285 	     dev;
286 	     device_find_next_child(&dev)) {
287 		udev = find_child_devnum(dev, devnum);
288 		if (udev)
289 			return udev;
290 	}
291 
292 	return NULL;
293 }
294 
295 struct usb_device *usb_get_dev_index(struct udevice *bus, int index)
296 {
297 	struct udevice *hub;
298 	int devnum = index + 1; /* Addresses are allocated from 1 on USB */
299 
300 	device_find_first_child(bus, &hub);
301 	if (device_get_uclass_id(hub) == UCLASS_USB_HUB)
302 		return find_child_devnum(hub, devnum);
303 
304 	return NULL;
305 }
306 
307 int usb_post_bind(struct udevice *dev)
308 {
309 	/* Scan the bus for devices */
310 	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
311 }
312 
313 int usb_port_reset(struct usb_device *parent, int portnr)
314 {
315 	unsigned short portstatus;
316 	int ret;
317 
318 	debug("%s: start\n", __func__);
319 
320 	if (parent) {
321 		/* reset the port for the second time */
322 		assert(portnr > 0);
323 		debug("%s: reset %d\n", __func__, portnr - 1);
324 		ret = legacy_hub_port_reset(parent, portnr - 1, &portstatus);
325 		if (ret < 0) {
326 			printf("\n     Couldn't reset port %i\n", portnr);
327 			return ret;
328 		}
329 	} else {
330 		debug("%s: reset root\n", __func__);
331 		usb_reset_root_port();
332 	}
333 
334 	return 0;
335 }
336 
337 int usb_legacy_port_reset(struct usb_device *parent, int portnr)
338 {
339 	return usb_port_reset(parent, portnr);
340 }
341 
342 int usb_setup_ehci_gadget(struct ehci_ctrl **ctlrp)
343 {
344 	struct usb_platdata *plat;
345 	struct udevice *dev;
346 	int ret;
347 
348 	/* Find the old device and remove it */
349 	ret = uclass_find_device_by_seq(UCLASS_USB, 0, true, &dev);
350 	if (ret)
351 		return ret;
352 	ret = device_remove(dev);
353 	if (ret)
354 		return ret;
355 
356 	plat = dev_get_platdata(dev);
357 	plat->init_type = USB_INIT_DEVICE;
358 	ret = device_probe(dev);
359 	if (ret)
360 		return ret;
361 	*ctlrp = dev_get_priv(dev);
362 
363 	return 0;
364 }
365 
366 /* returns 0 if no match, 1 if match */
367 int usb_match_device(const struct usb_device_descriptor *desc,
368 		     const struct usb_device_id *id)
369 {
370 	if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
371 	    id->idVendor != le16_to_cpu(desc->idVendor))
372 		return 0;
373 
374 	if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
375 	    id->idProduct != le16_to_cpu(desc->idProduct))
376 		return 0;
377 
378 	/* No need to test id->bcdDevice_lo != 0, since 0 is never
379 	   greater than any unsigned number. */
380 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO) &&
381 	    (id->bcdDevice_lo > le16_to_cpu(desc->bcdDevice)))
382 		return 0;
383 
384 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI) &&
385 	    (id->bcdDevice_hi < le16_to_cpu(desc->bcdDevice)))
386 		return 0;
387 
388 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS) &&
389 	    (id->bDeviceClass != desc->bDeviceClass))
390 		return 0;
391 
392 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS) &&
393 	    (id->bDeviceSubClass != desc->bDeviceSubClass))
394 		return 0;
395 
396 	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
397 	    (id->bDeviceProtocol != desc->bDeviceProtocol))
398 		return 0;
399 
400 	return 1;
401 }
402 
403 /* returns 0 if no match, 1 if match */
404 int usb_match_one_id_intf(const struct usb_device_descriptor *desc,
405 			  const struct usb_interface_descriptor *int_desc,
406 			  const struct usb_device_id *id)
407 {
408 	/* The interface class, subclass, protocol and number should never be
409 	 * checked for a match if the device class is Vendor Specific,
410 	 * unless the match record specifies the Vendor ID. */
411 	if (desc->bDeviceClass == USB_CLASS_VENDOR_SPEC &&
412 	    !(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
413 	    (id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |
414 				USB_DEVICE_ID_MATCH_INT_SUBCLASS |
415 				USB_DEVICE_ID_MATCH_INT_PROTOCOL |
416 				USB_DEVICE_ID_MATCH_INT_NUMBER)))
417 		return 0;
418 
419 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&
420 	    (id->bInterfaceClass != int_desc->bInterfaceClass))
421 		return 0;
422 
423 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS) &&
424 	    (id->bInterfaceSubClass != int_desc->bInterfaceSubClass))
425 		return 0;
426 
427 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL) &&
428 	    (id->bInterfaceProtocol != int_desc->bInterfaceProtocol))
429 		return 0;
430 
431 	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER) &&
432 	    (id->bInterfaceNumber != int_desc->bInterfaceNumber))
433 		return 0;
434 
435 	return 1;
436 }
437 
438 /* returns 0 if no match, 1 if match */
439 int usb_match_one_id(struct usb_device_descriptor *desc,
440 		     struct usb_interface_descriptor *int_desc,
441 		     const struct usb_device_id *id)
442 {
443 	if (!usb_match_device(desc, id))
444 		return 0;
445 
446 	return usb_match_one_id_intf(desc, int_desc, id);
447 }
448 
449 /**
450  * usb_find_and_bind_driver() - Find and bind the right USB driver
451  *
452  * This only looks at certain fields in the descriptor.
453  */
454 static int usb_find_and_bind_driver(struct udevice *parent,
455 				    struct usb_device_descriptor *desc,
456 				    struct usb_interface_descriptor *iface,
457 				    int bus_seq, int devnum,
458 				    struct udevice **devp)
459 {
460 	struct usb_driver_entry *start, *entry;
461 	int n_ents;
462 	int ret;
463 	char name[30], *str;
464 
465 	*devp = NULL;
466 	debug("%s: Searching for driver\n", __func__);
467 	start = ll_entry_start(struct usb_driver_entry, usb_driver_entry);
468 	n_ents = ll_entry_count(struct usb_driver_entry, usb_driver_entry);
469 	for (entry = start; entry != start + n_ents; entry++) {
470 		const struct usb_device_id *id;
471 		struct udevice *dev;
472 		const struct driver *drv;
473 		struct usb_dev_platdata *plat;
474 
475 		for (id = entry->match; id->match_flags; id++) {
476 			if (!usb_match_one_id(desc, iface, id))
477 				continue;
478 
479 			drv = entry->driver;
480 			/*
481 			 * We could pass the descriptor to the driver as
482 			 * platdata (instead of NULL) and allow its bind()
483 			 * method to return -ENOENT if it doesn't support this
484 			 * device. That way we could continue the search to
485 			 * find another driver. For now this doesn't seem
486 			 * necesssary, so just bind the first match.
487 			 */
488 			ret = device_bind(parent, drv, drv->name, NULL, -1,
489 					  &dev);
490 			if (ret)
491 				goto error;
492 			debug("%s: Match found: %s\n", __func__, drv->name);
493 			dev->driver_data = id->driver_info;
494 			plat = dev_get_parent_platdata(dev);
495 			plat->id = *id;
496 			*devp = dev;
497 			return 0;
498 		}
499 	}
500 
501 	/* Bind a generic driver so that the device can be used */
502 	snprintf(name, sizeof(name), "generic_bus_%x_dev_%x", bus_seq, devnum);
503 	str = strdup(name);
504 	if (!str)
505 		return -ENOMEM;
506 	ret = device_bind_driver(parent, "usb_dev_generic_drv", str, devp);
507 
508 error:
509 	debug("%s: No match found: %d\n", __func__, ret);
510 	return ret;
511 }
512 
513 /**
514  * usb_find_child() - Find an existing device which matches our needs
515  *
516  *
517  */
518 static int usb_find_child(struct udevice *parent,
519 			  struct usb_device_descriptor *desc,
520 			  struct usb_interface_descriptor *iface,
521 			  struct udevice **devp)
522 {
523 	struct udevice *dev;
524 
525 	*devp = NULL;
526 	for (device_find_first_child(parent, &dev);
527 	     dev;
528 	     device_find_next_child(&dev)) {
529 		struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
530 
531 		/* If this device is already in use, skip it */
532 		if (device_active(dev))
533 			continue;
534 		debug("   %s: name='%s', plat=%d, desc=%d\n", __func__,
535 		      dev->name, plat->id.bDeviceClass, desc->bDeviceClass);
536 		if (usb_match_one_id(desc, iface, &plat->id)) {
537 			*devp = dev;
538 			return 0;
539 		}
540 	}
541 
542 	return -ENOENT;
543 }
544 
545 int usb_scan_device(struct udevice *parent, int port,
546 		    enum usb_device_speed speed, struct udevice **devp)
547 {
548 	struct udevice *dev;
549 	bool created = false;
550 	struct usb_dev_platdata *plat;
551 	struct usb_bus_priv *priv;
552 	struct usb_device *parent_udev;
553 	int ret;
554 	ALLOC_CACHE_ALIGN_BUFFER(struct usb_device, udev, 1);
555 	struct usb_interface_descriptor *iface = &udev->config.if_desc[0].desc;
556 
557 	*devp = NULL;
558 	memset(udev, '\0', sizeof(*udev));
559 	udev->controller_dev = usb_get_bus(parent);
560 	priv = dev_get_uclass_priv(udev->controller_dev);
561 
562 	/*
563 	 * Somewhat nasty, this. We create a local device and use the normal
564 	 * USB stack to read its descriptor. Then we know what type of device
565 	 * to create for real.
566 	 *
567 	 * udev->dev is set to the parent, since we don't have a real device
568 	 * yet. The USB stack should not access udev.dev anyway, except perhaps
569 	 * to find the controller, and the controller will either be @parent,
570 	 * or some parent of @parent.
571 	 *
572 	 * Another option might be to create the device as a generic USB
573 	 * device, then morph it into the correct one when we know what it
574 	 * should be. This means that a generic USB device would morph into
575 	 * a network controller, or a USB flash stick, for example. However,
576 	 * we don't support such morphing and it isn't clear that it would
577 	 * be easy to do.
578 	 *
579 	 * Yet another option is to split out the USB stack parts of udev
580 	 * into something like a 'struct urb' (as Linux does) which can exist
581 	 * independently of any device. This feels cleaner, but calls for quite
582 	 * a big change to the USB stack.
583 	 *
584 	 * For now, the approach is to set up an empty udev, read its
585 	 * descriptor and assign it an address, then bind a real device and
586 	 * stash the resulting information into the device's parent
587 	 * platform data. Then when we probe it, usb_child_pre_probe() is called
588 	 * and it will pull the information out of the stash.
589 	 */
590 	udev->dev = parent;
591 	udev->speed = speed;
592 	udev->devnum = priv->next_addr + 1;
593 	udev->portnr = port;
594 	debug("Calling usb_setup_device(), portnr=%d\n", udev->portnr);
595 	parent_udev = device_get_uclass_id(parent) == UCLASS_USB_HUB ?
596 		dev_get_parentdata(parent) : NULL;
597 	ret = usb_setup_device(udev, priv->desc_before_addr, parent_udev, port);
598 	debug("read_descriptor for '%s': ret=%d\n", parent->name, ret);
599 	if (ret)
600 		return ret;
601 	ret = usb_find_child(parent, &udev->descriptor, iface, &dev);
602 	debug("** usb_find_child returns %d\n", ret);
603 	if (ret) {
604 		if (ret != -ENOENT)
605 			return ret;
606 		ret = usb_find_and_bind_driver(parent, &udev->descriptor, iface,
607 					       udev->controller_dev->seq,
608 					       udev->devnum, &dev);
609 		if (ret)
610 			return ret;
611 		created = true;
612 	}
613 	plat = dev_get_parent_platdata(dev);
614 	debug("%s: Probing '%s', plat=%p\n", __func__, dev->name, plat);
615 	plat->devnum = udev->devnum;
616 	plat->udev = udev;
617 	priv->next_addr++;
618 	ret = device_probe(dev);
619 	if (ret) {
620 		debug("%s: Device '%s' probe failed\n", __func__, dev->name);
621 		priv->next_addr--;
622 		if (created)
623 			device_unbind(dev);
624 		return ret;
625 	}
626 	*devp = dev;
627 
628 	return 0;
629 }
630 
631 /*
632  * Detect if a USB device has been plugged or unplugged.
633  */
634 int usb_detect_change(void)
635 {
636 	struct udevice *hub;
637 	struct uclass *uc;
638 	int change = 0;
639 	int ret;
640 
641 	ret = uclass_get(UCLASS_USB_HUB, &uc);
642 	if (ret)
643 		return ret;
644 
645 	uclass_foreach_dev(hub, uc) {
646 		struct usb_device *udev;
647 		struct udevice *dev;
648 
649 		if (!device_active(hub))
650 			continue;
651 		for (device_find_first_child(hub, &dev);
652 		     dev;
653 		     device_find_next_child(&dev)) {
654 			struct usb_port_status status;
655 
656 			if (!device_active(dev))
657 				continue;
658 
659 			udev = dev_get_parentdata(dev);
660 			if (usb_get_port_status(udev, udev->portnr, &status)
661 					< 0)
662 				/* USB request failed */
663 				continue;
664 
665 			if (le16_to_cpu(status.wPortChange) &
666 			    USB_PORT_STAT_C_CONNECTION)
667 				change++;
668 		}
669 	}
670 
671 	return change;
672 }
673 
674 int usb_child_post_bind(struct udevice *dev)
675 {
676 	struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
677 	const void *blob = gd->fdt_blob;
678 	int val;
679 
680 	if (dev->of_offset == -1)
681 		return 0;
682 
683 	/* We only support matching a few things */
684 	val = fdtdec_get_int(blob, dev->of_offset, "usb,device-class", -1);
685 	if (val != -1) {
686 		plat->id.match_flags |= USB_DEVICE_ID_MATCH_DEV_CLASS;
687 		plat->id.bDeviceClass = val;
688 	}
689 	val = fdtdec_get_int(blob, dev->of_offset, "usb,interface-class", -1);
690 	if (val != -1) {
691 		plat->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
692 		plat->id.bInterfaceClass = val;
693 	}
694 
695 	return 0;
696 }
697 
698 struct udevice *usb_get_bus(struct udevice *dev)
699 {
700 	struct udevice *bus;
701 
702 	for (bus = dev; bus && device_get_uclass_id(bus) != UCLASS_USB; )
703 		bus = bus->parent;
704 	if (!bus) {
705 		/* By design this cannot happen */
706 		assert(bus);
707 		debug("USB HUB '%s' does not have a controller\n", dev->name);
708 	}
709 
710 	return bus;
711 }
712 
713 int usb_child_pre_probe(struct udevice *dev)
714 {
715 	struct usb_device *udev = dev_get_parentdata(dev);
716 	struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
717 	int ret;
718 
719 	if (plat->udev) {
720 		/*
721 		 * Copy over all the values set in the on stack struct
722 		 * usb_device in usb_scan_device() to our final struct
723 		 * usb_device for this dev.
724 		 */
725 		*udev = *(plat->udev);
726 		/* And clear plat->udev as it will not be valid for long */
727 		plat->udev = NULL;
728 		udev->dev = dev;
729 	} else {
730 		/*
731 		 * This happens with devices which are explicitly bound
732 		 * instead of being discovered through usb_scan_device()
733 		 * such as sandbox emul devices.
734 		 */
735 		udev->dev = dev;
736 		udev->controller_dev = usb_get_bus(dev);
737 		udev->devnum = plat->devnum;
738 
739 		/*
740 		 * udev did not go through usb_scan_device(), so we need to
741 		 * select the config and read the config descriptors.
742 		 */
743 		ret = usb_select_config(udev);
744 		if (ret)
745 			return ret;
746 	}
747 
748 	return 0;
749 }
750 
751 UCLASS_DRIVER(usb) = {
752 	.id		= UCLASS_USB,
753 	.name		= "usb",
754 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
755 	.post_bind	= usb_post_bind,
756 	.priv_auto_alloc_size = sizeof(struct usb_uclass_priv),
757 	.per_child_auto_alloc_size = sizeof(struct usb_device),
758 	.per_device_auto_alloc_size = sizeof(struct usb_bus_priv),
759 	.child_post_bind = usb_child_post_bind,
760 	.child_pre_probe = usb_child_pre_probe,
761 	.per_child_platdata_auto_alloc_size = sizeof(struct usb_dev_platdata),
762 };
763 
764 UCLASS_DRIVER(usb_dev_generic) = {
765 	.id		= UCLASS_USB_DEV_GENERIC,
766 	.name		= "usb_dev_generic",
767 };
768 
769 U_BOOT_DRIVER(usb_dev_generic_drv) = {
770 	.id		= UCLASS_USB_DEV_GENERIC,
771 	.name		= "usb_dev_generic_drv",
772 };
773