xref: /openbmc/linux/drivers/usb/gadget/udc/core.c (revision 8730046c)
1 /**
2  * udc.c - Core UDC Framework
3  *
4  * Copyright (C) 2010 Texas Instruments
5  * Author: Felipe Balbi <balbi@ti.com>
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2  of
9  * the License as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/device.h>
23 #include <linux/list.h>
24 #include <linux/err.h>
25 #include <linux/dma-mapping.h>
26 #include <linux/workqueue.h>
27 
28 #include <linux/usb/ch9.h>
29 #include <linux/usb/gadget.h>
30 #include <linux/usb.h>
31 
32 #include "trace.h"
33 
34 /**
35  * struct usb_udc - describes one usb device controller
36  * @driver - the gadget driver pointer. For use by the class code
37  * @dev - the child device to the actual controller
38  * @gadget - the gadget. For use by the class code
39  * @list - for use by the udc class driver
40  * @vbus - for udcs who care about vbus status, this value is real vbus status;
41  * for udcs who do not care about vbus status, this value is always true
42  *
43  * This represents the internal data structure which is used by the UDC-class
44  * to hold information about udc driver and gadget together.
45  */
46 struct usb_udc {
47 	struct usb_gadget_driver	*driver;
48 	struct usb_gadget		*gadget;
49 	struct device			dev;
50 	struct list_head		list;
51 	bool				vbus;
52 };
53 
54 static struct class *udc_class;
55 static LIST_HEAD(udc_list);
56 static LIST_HEAD(gadget_driver_pending_list);
57 static DEFINE_MUTEX(udc_lock);
58 
59 static int udc_bind_to_driver(struct usb_udc *udc,
60 		struct usb_gadget_driver *driver);
61 
62 /* ------------------------------------------------------------------------- */
63 
64 /**
65  * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
66  * @ep:the endpoint being configured
67  * @maxpacket_limit:value of maximum packet size limit
68  *
69  * This function should be used only in UDC drivers to initialize endpoint
70  * (usually in probe function).
71  */
72 void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
73 					      unsigned maxpacket_limit)
74 {
75 	ep->maxpacket_limit = maxpacket_limit;
76 	ep->maxpacket = maxpacket_limit;
77 
78 	trace_usb_ep_set_maxpacket_limit(ep, 0);
79 }
80 EXPORT_SYMBOL_GPL(usb_ep_set_maxpacket_limit);
81 
82 /**
83  * usb_ep_enable - configure endpoint, making it usable
84  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
85  *	drivers discover endpoints through the ep_list of a usb_gadget.
86  *
87  * When configurations are set, or when interface settings change, the driver
88  * will enable or disable the relevant endpoints.  while it is enabled, an
89  * endpoint may be used for i/o until the driver receives a disconnect() from
90  * the host or until the endpoint is disabled.
91  *
92  * the ep0 implementation (which calls this routine) must ensure that the
93  * hardware capabilities of each endpoint match the descriptor provided
94  * for it.  for example, an endpoint named "ep2in-bulk" would be usable
95  * for interrupt transfers as well as bulk, but it likely couldn't be used
96  * for iso transfers or for endpoint 14.  some endpoints are fully
97  * configurable, with more generic names like "ep-a".  (remember that for
98  * USB, "in" means "towards the USB master".)
99  *
100  * returns zero, or a negative error code.
101  */
102 int usb_ep_enable(struct usb_ep *ep)
103 {
104 	int ret = 0;
105 
106 	if (ep->enabled)
107 		goto out;
108 
109 	ret = ep->ops->enable(ep, ep->desc);
110 	if (ret)
111 		goto out;
112 
113 	ep->enabled = true;
114 
115 out:
116 	trace_usb_ep_enable(ep, ret);
117 
118 	return ret;
119 }
120 EXPORT_SYMBOL_GPL(usb_ep_enable);
121 
122 /**
123  * usb_ep_disable - endpoint is no longer usable
124  * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
125  *
126  * no other task may be using this endpoint when this is called.
127  * any pending and uncompleted requests will complete with status
128  * indicating disconnect (-ESHUTDOWN) before this call returns.
129  * gadget drivers must call usb_ep_enable() again before queueing
130  * requests to the endpoint.
131  *
132  * returns zero, or a negative error code.
133  */
134 int usb_ep_disable(struct usb_ep *ep)
135 {
136 	int ret = 0;
137 
138 	if (!ep->enabled)
139 		goto out;
140 
141 	ret = ep->ops->disable(ep);
142 	if (ret) {
143 		ret = ret;
144 		goto out;
145 	}
146 
147 	ep->enabled = false;
148 
149 out:
150 	trace_usb_ep_disable(ep, ret);
151 
152 	return ret;
153 }
154 EXPORT_SYMBOL_GPL(usb_ep_disable);
155 
156 /**
157  * usb_ep_alloc_request - allocate a request object to use with this endpoint
158  * @ep:the endpoint to be used with with the request
159  * @gfp_flags:GFP_* flags to use
160  *
161  * Request objects must be allocated with this call, since they normally
162  * need controller-specific setup and may even need endpoint-specific
163  * resources such as allocation of DMA descriptors.
164  * Requests may be submitted with usb_ep_queue(), and receive a single
165  * completion callback.  Free requests with usb_ep_free_request(), when
166  * they are no longer needed.
167  *
168  * Returns the request, or null if one could not be allocated.
169  */
170 struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
171 						       gfp_t gfp_flags)
172 {
173 	struct usb_request *req = NULL;
174 
175 	req = ep->ops->alloc_request(ep, gfp_flags);
176 
177 	trace_usb_ep_alloc_request(ep, req, req ? 0 : -ENOMEM);
178 
179 	return req;
180 }
181 EXPORT_SYMBOL_GPL(usb_ep_alloc_request);
182 
183 /**
184  * usb_ep_free_request - frees a request object
185  * @ep:the endpoint associated with the request
186  * @req:the request being freed
187  *
188  * Reverses the effect of usb_ep_alloc_request().
189  * Caller guarantees the request is not queued, and that it will
190  * no longer be requeued (or otherwise used).
191  */
192 void usb_ep_free_request(struct usb_ep *ep,
193 				       struct usb_request *req)
194 {
195 	ep->ops->free_request(ep, req);
196 	trace_usb_ep_free_request(ep, req, 0);
197 }
198 EXPORT_SYMBOL_GPL(usb_ep_free_request);
199 
200 /**
201  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
202  * @ep:the endpoint associated with the request
203  * @req:the request being submitted
204  * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
205  *	pre-allocate all necessary memory with the request.
206  *
207  * This tells the device controller to perform the specified request through
208  * that endpoint (reading or writing a buffer).  When the request completes,
209  * including being canceled by usb_ep_dequeue(), the request's completion
210  * routine is called to return the request to the driver.  Any endpoint
211  * (except control endpoints like ep0) may have more than one transfer
212  * request queued; they complete in FIFO order.  Once a gadget driver
213  * submits a request, that request may not be examined or modified until it
214  * is given back to that driver through the completion callback.
215  *
216  * Each request is turned into one or more packets.  The controller driver
217  * never merges adjacent requests into the same packet.  OUT transfers
218  * will sometimes use data that's already buffered in the hardware.
219  * Drivers can rely on the fact that the first byte of the request's buffer
220  * always corresponds to the first byte of some USB packet, for both
221  * IN and OUT transfers.
222  *
223  * Bulk endpoints can queue any amount of data; the transfer is packetized
224  * automatically.  The last packet will be short if the request doesn't fill it
225  * out completely.  Zero length packets (ZLPs) should be avoided in portable
226  * protocols since not all usb hardware can successfully handle zero length
227  * packets.  (ZLPs may be explicitly written, and may be implicitly written if
228  * the request 'zero' flag is set.)  Bulk endpoints may also be used
229  * for interrupt transfers; but the reverse is not true, and some endpoints
230  * won't support every interrupt transfer.  (Such as 768 byte packets.)
231  *
232  * Interrupt-only endpoints are less functional than bulk endpoints, for
233  * example by not supporting queueing or not handling buffers that are
234  * larger than the endpoint's maxpacket size.  They may also treat data
235  * toggle differently.
236  *
237  * Control endpoints ... after getting a setup() callback, the driver queues
238  * one response (even if it would be zero length).  That enables the
239  * status ack, after transferring data as specified in the response.  Setup
240  * functions may return negative error codes to generate protocol stalls.
241  * (Note that some USB device controllers disallow protocol stall responses
242  * in some cases.)  When control responses are deferred (the response is
243  * written after the setup callback returns), then usb_ep_set_halt() may be
244  * used on ep0 to trigger protocol stalls.  Depending on the controller,
245  * it may not be possible to trigger a status-stage protocol stall when the
246  * data stage is over, that is, from within the response's completion
247  * routine.
248  *
249  * For periodic endpoints, like interrupt or isochronous ones, the usb host
250  * arranges to poll once per interval, and the gadget driver usually will
251  * have queued some data to transfer at that time.
252  *
253  * Returns zero, or a negative error code.  Endpoints that are not enabled
254  * report errors; errors will also be
255  * reported when the usb peripheral is disconnected.
256  */
257 int usb_ep_queue(struct usb_ep *ep,
258 			       struct usb_request *req, gfp_t gfp_flags)
259 {
260 	int ret = 0;
261 
262 	if (WARN_ON_ONCE(!ep->enabled && ep->address)) {
263 		ret = -ESHUTDOWN;
264 		goto out;
265 	}
266 
267 	ret = ep->ops->queue(ep, req, gfp_flags);
268 
269 out:
270 	trace_usb_ep_queue(ep, req, ret);
271 
272 	return ret;
273 }
274 EXPORT_SYMBOL_GPL(usb_ep_queue);
275 
276 /**
277  * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
278  * @ep:the endpoint associated with the request
279  * @req:the request being canceled
280  *
281  * If the request is still active on the endpoint, it is dequeued and its
282  * completion routine is called (with status -ECONNRESET); else a negative
283  * error code is returned. This is guaranteed to happen before the call to
284  * usb_ep_dequeue() returns.
285  *
286  * Note that some hardware can't clear out write fifos (to unlink the request
287  * at the head of the queue) except as part of disconnecting from usb. Such
288  * restrictions prevent drivers from supporting configuration changes,
289  * even to configuration zero (a "chapter 9" requirement).
290  */
291 int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
292 {
293 	int ret;
294 
295 	ret = ep->ops->dequeue(ep, req);
296 	trace_usb_ep_dequeue(ep, req, ret);
297 
298 	return ret;
299 }
300 EXPORT_SYMBOL_GPL(usb_ep_dequeue);
301 
302 /**
303  * usb_ep_set_halt - sets the endpoint halt feature.
304  * @ep: the non-isochronous endpoint being stalled
305  *
306  * Use this to stall an endpoint, perhaps as an error report.
307  * Except for control endpoints,
308  * the endpoint stays halted (will not stream any data) until the host
309  * clears this feature; drivers may need to empty the endpoint's request
310  * queue first, to make sure no inappropriate transfers happen.
311  *
312  * Note that while an endpoint CLEAR_FEATURE will be invisible to the
313  * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
314  * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
315  * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
316  *
317  * Returns zero, or a negative error code.  On success, this call sets
318  * underlying hardware state that blocks data transfers.
319  * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
320  * transfer requests are still queued, or if the controller hardware
321  * (usually a FIFO) still holds bytes that the host hasn't collected.
322  */
323 int usb_ep_set_halt(struct usb_ep *ep)
324 {
325 	int ret;
326 
327 	ret = ep->ops->set_halt(ep, 1);
328 	trace_usb_ep_set_halt(ep, ret);
329 
330 	return ret;
331 }
332 EXPORT_SYMBOL_GPL(usb_ep_set_halt);
333 
334 /**
335  * usb_ep_clear_halt - clears endpoint halt, and resets toggle
336  * @ep:the bulk or interrupt endpoint being reset
337  *
338  * Use this when responding to the standard usb "set interface" request,
339  * for endpoints that aren't reconfigured, after clearing any other state
340  * in the endpoint's i/o queue.
341  *
342  * Returns zero, or a negative error code.  On success, this call clears
343  * the underlying hardware state reflecting endpoint halt and data toggle.
344  * Note that some hardware can't support this request (like pxa2xx_udc),
345  * and accordingly can't correctly implement interface altsettings.
346  */
347 int usb_ep_clear_halt(struct usb_ep *ep)
348 {
349 	int ret;
350 
351 	ret = ep->ops->set_halt(ep, 0);
352 	trace_usb_ep_clear_halt(ep, ret);
353 
354 	return ret;
355 }
356 EXPORT_SYMBOL_GPL(usb_ep_clear_halt);
357 
358 /**
359  * usb_ep_set_wedge - sets the halt feature and ignores clear requests
360  * @ep: the endpoint being wedged
361  *
362  * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
363  * requests. If the gadget driver clears the halt status, it will
364  * automatically unwedge the endpoint.
365  *
366  * Returns zero on success, else negative errno.
367  */
368 int usb_ep_set_wedge(struct usb_ep *ep)
369 {
370 	int ret;
371 
372 	if (ep->ops->set_wedge)
373 		ret = ep->ops->set_wedge(ep);
374 	else
375 		ret = ep->ops->set_halt(ep, 1);
376 
377 	trace_usb_ep_set_wedge(ep, ret);
378 
379 	return ret;
380 }
381 EXPORT_SYMBOL_GPL(usb_ep_set_wedge);
382 
383 /**
384  * usb_ep_fifo_status - returns number of bytes in fifo, or error
385  * @ep: the endpoint whose fifo status is being checked.
386  *
387  * FIFO endpoints may have "unclaimed data" in them in certain cases,
388  * such as after aborted transfers.  Hosts may not have collected all
389  * the IN data written by the gadget driver (and reported by a request
390  * completion).  The gadget driver may not have collected all the data
391  * written OUT to it by the host.  Drivers that need precise handling for
392  * fault reporting or recovery may need to use this call.
393  *
394  * This returns the number of such bytes in the fifo, or a negative
395  * errno if the endpoint doesn't use a FIFO or doesn't support such
396  * precise handling.
397  */
398 int usb_ep_fifo_status(struct usb_ep *ep)
399 {
400 	int ret;
401 
402 	if (ep->ops->fifo_status)
403 		ret = ep->ops->fifo_status(ep);
404 	else
405 		ret = -EOPNOTSUPP;
406 
407 	trace_usb_ep_fifo_status(ep, ret);
408 
409 	return ret;
410 }
411 EXPORT_SYMBOL_GPL(usb_ep_fifo_status);
412 
413 /**
414  * usb_ep_fifo_flush - flushes contents of a fifo
415  * @ep: the endpoint whose fifo is being flushed.
416  *
417  * This call may be used to flush the "unclaimed data" that may exist in
418  * an endpoint fifo after abnormal transaction terminations.  The call
419  * must never be used except when endpoint is not being used for any
420  * protocol translation.
421  */
422 void usb_ep_fifo_flush(struct usb_ep *ep)
423 {
424 	if (ep->ops->fifo_flush)
425 		ep->ops->fifo_flush(ep);
426 
427 	trace_usb_ep_fifo_flush(ep, 0);
428 }
429 EXPORT_SYMBOL_GPL(usb_ep_fifo_flush);
430 
431 /* ------------------------------------------------------------------------- */
432 
433 /**
434  * usb_gadget_frame_number - returns the current frame number
435  * @gadget: controller that reports the frame number
436  *
437  * Returns the usb frame number, normally eleven bits from a SOF packet,
438  * or negative errno if this device doesn't support this capability.
439  */
440 int usb_gadget_frame_number(struct usb_gadget *gadget)
441 {
442 	int ret;
443 
444 	ret = gadget->ops->get_frame(gadget);
445 
446 	trace_usb_gadget_frame_number(gadget, ret);
447 
448 	return ret;
449 }
450 EXPORT_SYMBOL_GPL(usb_gadget_frame_number);
451 
452 /**
453  * usb_gadget_wakeup - tries to wake up the host connected to this gadget
454  * @gadget: controller used to wake up the host
455  *
456  * Returns zero on success, else negative error code if the hardware
457  * doesn't support such attempts, or its support has not been enabled
458  * by the usb host.  Drivers must return device descriptors that report
459  * their ability to support this, or hosts won't enable it.
460  *
461  * This may also try to use SRP to wake the host and start enumeration,
462  * even if OTG isn't otherwise in use.  OTG devices may also start
463  * remote wakeup even when hosts don't explicitly enable it.
464  */
465 int usb_gadget_wakeup(struct usb_gadget *gadget)
466 {
467 	int ret = 0;
468 
469 	if (!gadget->ops->wakeup) {
470 		ret = -EOPNOTSUPP;
471 		goto out;
472 	}
473 
474 	ret = gadget->ops->wakeup(gadget);
475 
476 out:
477 	trace_usb_gadget_wakeup(gadget, ret);
478 
479 	return ret;
480 }
481 EXPORT_SYMBOL_GPL(usb_gadget_wakeup);
482 
483 /**
484  * usb_gadget_set_selfpowered - sets the device selfpowered feature.
485  * @gadget:the device being declared as self-powered
486  *
487  * this affects the device status reported by the hardware driver
488  * to reflect that it now has a local power supply.
489  *
490  * returns zero on success, else negative errno.
491  */
492 int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
493 {
494 	int ret = 0;
495 
496 	if (!gadget->ops->set_selfpowered) {
497 		ret = -EOPNOTSUPP;
498 		goto out;
499 	}
500 
501 	ret = gadget->ops->set_selfpowered(gadget, 1);
502 
503 out:
504 	trace_usb_gadget_set_selfpowered(gadget, ret);
505 
506 	return ret;
507 }
508 EXPORT_SYMBOL_GPL(usb_gadget_set_selfpowered);
509 
510 /**
511  * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
512  * @gadget:the device being declared as bus-powered
513  *
514  * this affects the device status reported by the hardware driver.
515  * some hardware may not support bus-powered operation, in which
516  * case this feature's value can never change.
517  *
518  * returns zero on success, else negative errno.
519  */
520 int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
521 {
522 	int ret = 0;
523 
524 	if (!gadget->ops->set_selfpowered) {
525 		ret = -EOPNOTSUPP;
526 		goto out;
527 	}
528 
529 	ret = gadget->ops->set_selfpowered(gadget, 0);
530 
531 out:
532 	trace_usb_gadget_clear_selfpowered(gadget, ret);
533 
534 	return ret;
535 }
536 EXPORT_SYMBOL_GPL(usb_gadget_clear_selfpowered);
537 
538 /**
539  * usb_gadget_vbus_connect - Notify controller that VBUS is powered
540  * @gadget:The device which now has VBUS power.
541  * Context: can sleep
542  *
543  * This call is used by a driver for an external transceiver (or GPIO)
544  * that detects a VBUS power session starting.  Common responses include
545  * resuming the controller, activating the D+ (or D-) pullup to let the
546  * host detect that a USB device is attached, and starting to draw power
547  * (8mA or possibly more, especially after SET_CONFIGURATION).
548  *
549  * Returns zero on success, else negative errno.
550  */
551 int usb_gadget_vbus_connect(struct usb_gadget *gadget)
552 {
553 	int ret = 0;
554 
555 	if (!gadget->ops->vbus_session) {
556 		ret = -EOPNOTSUPP;
557 		goto out;
558 	}
559 
560 	ret = gadget->ops->vbus_session(gadget, 1);
561 
562 out:
563 	trace_usb_gadget_vbus_connect(gadget, ret);
564 
565 	return ret;
566 }
567 EXPORT_SYMBOL_GPL(usb_gadget_vbus_connect);
568 
569 /**
570  * usb_gadget_vbus_draw - constrain controller's VBUS power usage
571  * @gadget:The device whose VBUS usage is being described
572  * @mA:How much current to draw, in milliAmperes.  This should be twice
573  *	the value listed in the configuration descriptor bMaxPower field.
574  *
575  * This call is used by gadget drivers during SET_CONFIGURATION calls,
576  * reporting how much power the device may consume.  For example, this
577  * could affect how quickly batteries are recharged.
578  *
579  * Returns zero on success, else negative errno.
580  */
581 int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
582 {
583 	int ret = 0;
584 
585 	if (!gadget->ops->vbus_draw) {
586 		ret = -EOPNOTSUPP;
587 		goto out;
588 	}
589 
590 	ret = gadget->ops->vbus_draw(gadget, mA);
591 	if (!ret)
592 		gadget->mA = mA;
593 
594 out:
595 	trace_usb_gadget_vbus_draw(gadget, ret);
596 
597 	return ret;
598 }
599 EXPORT_SYMBOL_GPL(usb_gadget_vbus_draw);
600 
601 /**
602  * usb_gadget_vbus_disconnect - notify controller about VBUS session end
603  * @gadget:the device whose VBUS supply is being described
604  * Context: can sleep
605  *
606  * This call is used by a driver for an external transceiver (or GPIO)
607  * that detects a VBUS power session ending.  Common responses include
608  * reversing everything done in usb_gadget_vbus_connect().
609  *
610  * Returns zero on success, else negative errno.
611  */
612 int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
613 {
614 	int ret = 0;
615 
616 	if (!gadget->ops->vbus_session) {
617 		ret = -EOPNOTSUPP;
618 		goto out;
619 	}
620 
621 	ret = gadget->ops->vbus_session(gadget, 0);
622 
623 out:
624 	trace_usb_gadget_vbus_disconnect(gadget, ret);
625 
626 	return ret;
627 }
628 EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect);
629 
630 /**
631  * usb_gadget_connect - software-controlled connect to USB host
632  * @gadget:the peripheral being connected
633  *
634  * Enables the D+ (or potentially D-) pullup.  The host will start
635  * enumerating this gadget when the pullup is active and a VBUS session
636  * is active (the link is powered).  This pullup is always enabled unless
637  * usb_gadget_disconnect() has been used to disable it.
638  *
639  * Returns zero on success, else negative errno.
640  */
641 int usb_gadget_connect(struct usb_gadget *gadget)
642 {
643 	int ret = 0;
644 
645 	if (!gadget->ops->pullup) {
646 		ret = -EOPNOTSUPP;
647 		goto out;
648 	}
649 
650 	if (gadget->deactivated) {
651 		/*
652 		 * If gadget is deactivated we only save new state.
653 		 * Gadget will be connected automatically after activation.
654 		 */
655 		gadget->connected = true;
656 		goto out;
657 	}
658 
659 	ret = gadget->ops->pullup(gadget, 1);
660 	if (!ret)
661 		gadget->connected = 1;
662 
663 out:
664 	trace_usb_gadget_connect(gadget, ret);
665 
666 	return ret;
667 }
668 EXPORT_SYMBOL_GPL(usb_gadget_connect);
669 
670 /**
671  * usb_gadget_disconnect - software-controlled disconnect from USB host
672  * @gadget:the peripheral being disconnected
673  *
674  * Disables the D+ (or potentially D-) pullup, which the host may see
675  * as a disconnect (when a VBUS session is active).  Not all systems
676  * support software pullup controls.
677  *
678  * Returns zero on success, else negative errno.
679  */
680 int usb_gadget_disconnect(struct usb_gadget *gadget)
681 {
682 	int ret = 0;
683 
684 	if (!gadget->ops->pullup) {
685 		ret = -EOPNOTSUPP;
686 		goto out;
687 	}
688 
689 	if (gadget->deactivated) {
690 		/*
691 		 * If gadget is deactivated we only save new state.
692 		 * Gadget will stay disconnected after activation.
693 		 */
694 		gadget->connected = false;
695 		goto out;
696 	}
697 
698 	ret = gadget->ops->pullup(gadget, 0);
699 	if (!ret)
700 		gadget->connected = 0;
701 
702 out:
703 	trace_usb_gadget_disconnect(gadget, ret);
704 
705 	return ret;
706 }
707 EXPORT_SYMBOL_GPL(usb_gadget_disconnect);
708 
709 /**
710  * usb_gadget_deactivate - deactivate function which is not ready to work
711  * @gadget: the peripheral being deactivated
712  *
713  * This routine may be used during the gadget driver bind() call to prevent
714  * the peripheral from ever being visible to the USB host, unless later
715  * usb_gadget_activate() is called.  For example, user mode components may
716  * need to be activated before the system can talk to hosts.
717  *
718  * Returns zero on success, else negative errno.
719  */
720 int usb_gadget_deactivate(struct usb_gadget *gadget)
721 {
722 	int ret = 0;
723 
724 	if (gadget->deactivated)
725 		goto out;
726 
727 	if (gadget->connected) {
728 		ret = usb_gadget_disconnect(gadget);
729 		if (ret)
730 			goto out;
731 
732 		/*
733 		 * If gadget was being connected before deactivation, we want
734 		 * to reconnect it in usb_gadget_activate().
735 		 */
736 		gadget->connected = true;
737 	}
738 	gadget->deactivated = true;
739 
740 out:
741 	trace_usb_gadget_deactivate(gadget, ret);
742 
743 	return ret;
744 }
745 EXPORT_SYMBOL_GPL(usb_gadget_deactivate);
746 
747 /**
748  * usb_gadget_activate - activate function which is not ready to work
749  * @gadget: the peripheral being activated
750  *
751  * This routine activates gadget which was previously deactivated with
752  * usb_gadget_deactivate() call. It calls usb_gadget_connect() if needed.
753  *
754  * Returns zero on success, else negative errno.
755  */
756 int usb_gadget_activate(struct usb_gadget *gadget)
757 {
758 	int ret = 0;
759 
760 	if (!gadget->deactivated)
761 		goto out;
762 
763 	gadget->deactivated = false;
764 
765 	/*
766 	 * If gadget has been connected before deactivation, or became connected
767 	 * while it was being deactivated, we call usb_gadget_connect().
768 	 */
769 	if (gadget->connected)
770 		ret = usb_gadget_connect(gadget);
771 
772 out:
773 	trace_usb_gadget_activate(gadget, ret);
774 
775 	return ret;
776 }
777 EXPORT_SYMBOL_GPL(usb_gadget_activate);
778 
779 /* ------------------------------------------------------------------------- */
780 
781 #ifdef	CONFIG_HAS_DMA
782 
783 int usb_gadget_map_request_by_dev(struct device *dev,
784 		struct usb_request *req, int is_in)
785 {
786 	if (req->length == 0)
787 		return 0;
788 
789 	if (req->num_sgs) {
790 		int     mapped;
791 
792 		mapped = dma_map_sg(dev, req->sg, req->num_sgs,
793 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
794 		if (mapped == 0) {
795 			dev_err(dev, "failed to map SGs\n");
796 			return -EFAULT;
797 		}
798 
799 		req->num_mapped_sgs = mapped;
800 	} else {
801 		req->dma = dma_map_single(dev, req->buf, req->length,
802 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
803 
804 		if (dma_mapping_error(dev, req->dma)) {
805 			dev_err(dev, "failed to map buffer\n");
806 			return -EFAULT;
807 		}
808 	}
809 
810 	return 0;
811 }
812 EXPORT_SYMBOL_GPL(usb_gadget_map_request_by_dev);
813 
814 int usb_gadget_map_request(struct usb_gadget *gadget,
815 		struct usb_request *req, int is_in)
816 {
817 	return usb_gadget_map_request_by_dev(gadget->dev.parent, req, is_in);
818 }
819 EXPORT_SYMBOL_GPL(usb_gadget_map_request);
820 
821 void usb_gadget_unmap_request_by_dev(struct device *dev,
822 		struct usb_request *req, int is_in)
823 {
824 	if (req->length == 0)
825 		return;
826 
827 	if (req->num_mapped_sgs) {
828 		dma_unmap_sg(dev, req->sg, req->num_sgs,
829 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
830 
831 		req->num_mapped_sgs = 0;
832 	} else {
833 		dma_unmap_single(dev, req->dma, req->length,
834 				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
835 	}
836 }
837 EXPORT_SYMBOL_GPL(usb_gadget_unmap_request_by_dev);
838 
839 void usb_gadget_unmap_request(struct usb_gadget *gadget,
840 		struct usb_request *req, int is_in)
841 {
842 	usb_gadget_unmap_request_by_dev(gadget->dev.parent, req, is_in);
843 }
844 EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);
845 
846 #endif	/* CONFIG_HAS_DMA */
847 
848 /* ------------------------------------------------------------------------- */
849 
850 /**
851  * usb_gadget_giveback_request - give the request back to the gadget layer
852  * Context: in_interrupt()
853  *
854  * This is called by device controller drivers in order to return the
855  * completed request back to the gadget layer.
856  */
857 void usb_gadget_giveback_request(struct usb_ep *ep,
858 		struct usb_request *req)
859 {
860 	if (likely(req->status == 0))
861 		usb_led_activity(USB_LED_EVENT_GADGET);
862 
863 	trace_usb_gadget_giveback_request(ep, req, 0);
864 
865 	req->complete(ep, req);
866 }
867 EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);
868 
869 /* ------------------------------------------------------------------------- */
870 
871 /**
872  * gadget_find_ep_by_name - returns ep whose name is the same as sting passed
873  *	in second parameter or NULL if searched endpoint not found
874  * @g: controller to check for quirk
875  * @name: name of searched endpoint
876  */
877 struct usb_ep *gadget_find_ep_by_name(struct usb_gadget *g, const char *name)
878 {
879 	struct usb_ep *ep;
880 
881 	gadget_for_each_ep(ep, g) {
882 		if (!strcmp(ep->name, name))
883 			return ep;
884 	}
885 
886 	return NULL;
887 }
888 EXPORT_SYMBOL_GPL(gadget_find_ep_by_name);
889 
890 /* ------------------------------------------------------------------------- */
891 
892 int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
893 		struct usb_ep *ep, struct usb_endpoint_descriptor *desc,
894 		struct usb_ss_ep_comp_descriptor *ep_comp)
895 {
896 	u8		type;
897 	u16		max;
898 	int		num_req_streams = 0;
899 
900 	/* endpoint already claimed? */
901 	if (ep->claimed)
902 		return 0;
903 
904 	type = usb_endpoint_type(desc);
905 	max = 0x7ff & usb_endpoint_maxp(desc);
906 
907 	if (usb_endpoint_dir_in(desc) && !ep->caps.dir_in)
908 		return 0;
909 	if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out)
910 		return 0;
911 
912 	if (max > ep->maxpacket_limit)
913 		return 0;
914 
915 	/* "high bandwidth" works only at high speed */
916 	if (!gadget_is_dualspeed(gadget) && usb_endpoint_maxp(desc) & (3<<11))
917 		return 0;
918 
919 	switch (type) {
920 	case USB_ENDPOINT_XFER_CONTROL:
921 		/* only support ep0 for portable CONTROL traffic */
922 		return 0;
923 	case USB_ENDPOINT_XFER_ISOC:
924 		if (!ep->caps.type_iso)
925 			return 0;
926 		/* ISO:  limit 1023 bytes full speed, 1024 high/super speed */
927 		if (!gadget_is_dualspeed(gadget) && max > 1023)
928 			return 0;
929 		break;
930 	case USB_ENDPOINT_XFER_BULK:
931 		if (!ep->caps.type_bulk)
932 			return 0;
933 		if (ep_comp && gadget_is_superspeed(gadget)) {
934 			/* Get the number of required streams from the
935 			 * EP companion descriptor and see if the EP
936 			 * matches it
937 			 */
938 			num_req_streams = ep_comp->bmAttributes & 0x1f;
939 			if (num_req_streams > ep->max_streams)
940 				return 0;
941 		}
942 		break;
943 	case USB_ENDPOINT_XFER_INT:
944 		/* Bulk endpoints handle interrupt transfers,
945 		 * except the toggle-quirky iso-synch kind
946 		 */
947 		if (!ep->caps.type_int && !ep->caps.type_bulk)
948 			return 0;
949 		/* INT:  limit 64 bytes full speed, 1024 high/super speed */
950 		if (!gadget_is_dualspeed(gadget) && max > 64)
951 			return 0;
952 		break;
953 	}
954 
955 	return 1;
956 }
957 EXPORT_SYMBOL_GPL(usb_gadget_ep_match_desc);
958 
959 /* ------------------------------------------------------------------------- */
960 
961 static void usb_gadget_state_work(struct work_struct *work)
962 {
963 	struct usb_gadget *gadget = work_to_gadget(work);
964 	struct usb_udc *udc = gadget->udc;
965 
966 	if (udc)
967 		sysfs_notify(&udc->dev.kobj, NULL, "state");
968 }
969 
970 void usb_gadget_set_state(struct usb_gadget *gadget,
971 		enum usb_device_state state)
972 {
973 	gadget->state = state;
974 	schedule_work(&gadget->work);
975 }
976 EXPORT_SYMBOL_GPL(usb_gadget_set_state);
977 
978 /* ------------------------------------------------------------------------- */
979 
980 static void usb_udc_connect_control(struct usb_udc *udc)
981 {
982 	if (udc->vbus)
983 		usb_gadget_connect(udc->gadget);
984 	else
985 		usb_gadget_disconnect(udc->gadget);
986 }
987 
988 /**
989  * usb_udc_vbus_handler - updates the udc core vbus status, and try to
990  * connect or disconnect gadget
991  * @gadget: The gadget which vbus change occurs
992  * @status: The vbus status
993  *
994  * The udc driver calls it when it wants to connect or disconnect gadget
995  * according to vbus status.
996  */
997 void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status)
998 {
999 	struct usb_udc *udc = gadget->udc;
1000 
1001 	if (udc) {
1002 		udc->vbus = status;
1003 		usb_udc_connect_control(udc);
1004 	}
1005 }
1006 EXPORT_SYMBOL_GPL(usb_udc_vbus_handler);
1007 
1008 /**
1009  * usb_gadget_udc_reset - notifies the udc core that bus reset occurs
1010  * @gadget: The gadget which bus reset occurs
1011  * @driver: The gadget driver we want to notify
1012  *
1013  * If the udc driver has bus reset handler, it needs to call this when the bus
1014  * reset occurs, it notifies the gadget driver that the bus reset occurs as
1015  * well as updates gadget state.
1016  */
1017 void usb_gadget_udc_reset(struct usb_gadget *gadget,
1018 		struct usb_gadget_driver *driver)
1019 {
1020 	driver->reset(gadget);
1021 	usb_gadget_set_state(gadget, USB_STATE_DEFAULT);
1022 }
1023 EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
1024 
1025 /**
1026  * usb_gadget_udc_start - tells usb device controller to start up
1027  * @udc: The UDC to be started
1028  *
1029  * This call is issued by the UDC Class driver when it's about
1030  * to register a gadget driver to the device controller, before
1031  * calling gadget driver's bind() method.
1032  *
1033  * It allows the controller to be powered off until strictly
1034  * necessary to have it powered on.
1035  *
1036  * Returns zero on success, else negative errno.
1037  */
1038 static inline int usb_gadget_udc_start(struct usb_udc *udc)
1039 {
1040 	return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
1041 }
1042 
1043 /**
1044  * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
1045  * @gadget: The device we want to stop activity
1046  * @driver: The driver to unbind from @gadget
1047  *
1048  * This call is issued by the UDC Class driver after calling
1049  * gadget driver's unbind() method.
1050  *
1051  * The details are implementation specific, but it can go as
1052  * far as powering off UDC completely and disable its data
1053  * line pullups.
1054  */
1055 static inline void usb_gadget_udc_stop(struct usb_udc *udc)
1056 {
1057 	udc->gadget->ops->udc_stop(udc->gadget);
1058 }
1059 
1060 /**
1061  * usb_udc_release - release the usb_udc struct
1062  * @dev: the dev member within usb_udc
1063  *
1064  * This is called by driver's core in order to free memory once the last
1065  * reference is released.
1066  */
1067 static void usb_udc_release(struct device *dev)
1068 {
1069 	struct usb_udc *udc;
1070 
1071 	udc = container_of(dev, struct usb_udc, dev);
1072 	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
1073 	kfree(udc);
1074 }
1075 
1076 static const struct attribute_group *usb_udc_attr_groups[];
1077 
1078 static void usb_udc_nop_release(struct device *dev)
1079 {
1080 	dev_vdbg(dev, "%s\n", __func__);
1081 }
1082 
1083 /**
1084  * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
1085  * @parent: the parent device to this udc. Usually the controller driver's
1086  * device.
1087  * @gadget: the gadget to be added to the list.
1088  * @release: a gadget release function.
1089  *
1090  * Returns zero on success, negative errno otherwise.
1091  */
1092 int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
1093 		void (*release)(struct device *dev))
1094 {
1095 	struct usb_udc		*udc;
1096 	struct usb_gadget_driver *driver;
1097 	int			ret = -ENOMEM;
1098 
1099 	udc = kzalloc(sizeof(*udc), GFP_KERNEL);
1100 	if (!udc)
1101 		goto err1;
1102 
1103 	dev_set_name(&gadget->dev, "gadget");
1104 	INIT_WORK(&gadget->work, usb_gadget_state_work);
1105 	gadget->dev.parent = parent;
1106 
1107 	if (release)
1108 		gadget->dev.release = release;
1109 	else
1110 		gadget->dev.release = usb_udc_nop_release;
1111 
1112 	ret = device_register(&gadget->dev);
1113 	if (ret)
1114 		goto err2;
1115 
1116 	device_initialize(&udc->dev);
1117 	udc->dev.release = usb_udc_release;
1118 	udc->dev.class = udc_class;
1119 	udc->dev.groups = usb_udc_attr_groups;
1120 	udc->dev.parent = parent;
1121 	ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
1122 	if (ret)
1123 		goto err3;
1124 
1125 	udc->gadget = gadget;
1126 	gadget->udc = udc;
1127 
1128 	mutex_lock(&udc_lock);
1129 	list_add_tail(&udc->list, &udc_list);
1130 
1131 	ret = device_add(&udc->dev);
1132 	if (ret)
1133 		goto err4;
1134 
1135 	usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
1136 	udc->vbus = true;
1137 
1138 	/* pick up one of pending gadget drivers */
1139 	list_for_each_entry(driver, &gadget_driver_pending_list, pending) {
1140 		if (!driver->udc_name || strcmp(driver->udc_name,
1141 						dev_name(&udc->dev)) == 0) {
1142 			ret = udc_bind_to_driver(udc, driver);
1143 			if (ret != -EPROBE_DEFER)
1144 				list_del(&driver->pending);
1145 			if (ret)
1146 				goto err5;
1147 			break;
1148 		}
1149 	}
1150 
1151 	mutex_unlock(&udc_lock);
1152 
1153 	return 0;
1154 
1155 err5:
1156 	device_del(&udc->dev);
1157 
1158 err4:
1159 	list_del(&udc->list);
1160 	mutex_unlock(&udc_lock);
1161 
1162 err3:
1163 	put_device(&udc->dev);
1164 	device_del(&gadget->dev);
1165 
1166 err2:
1167 	put_device(&gadget->dev);
1168 	kfree(udc);
1169 
1170 err1:
1171 	return ret;
1172 }
1173 EXPORT_SYMBOL_GPL(usb_add_gadget_udc_release);
1174 
1175 /**
1176  * usb_get_gadget_udc_name - get the name of the first UDC controller
1177  * This functions returns the name of the first UDC controller in the system.
1178  * Please note that this interface is usefull only for legacy drivers which
1179  * assume that there is only one UDC controller in the system and they need to
1180  * get its name before initialization. There is no guarantee that the UDC
1181  * of the returned name will be still available, when gadget driver registers
1182  * itself.
1183  *
1184  * Returns pointer to string with UDC controller name on success, NULL
1185  * otherwise. Caller should kfree() returned string.
1186  */
1187 char *usb_get_gadget_udc_name(void)
1188 {
1189 	struct usb_udc *udc;
1190 	char *name = NULL;
1191 
1192 	/* For now we take the first available UDC */
1193 	mutex_lock(&udc_lock);
1194 	list_for_each_entry(udc, &udc_list, list) {
1195 		if (!udc->driver) {
1196 			name = kstrdup(udc->gadget->name, GFP_KERNEL);
1197 			break;
1198 		}
1199 	}
1200 	mutex_unlock(&udc_lock);
1201 	return name;
1202 }
1203 EXPORT_SYMBOL_GPL(usb_get_gadget_udc_name);
1204 
1205 /**
1206  * usb_add_gadget_udc - adds a new gadget to the udc class driver list
1207  * @parent: the parent device to this udc. Usually the controller
1208  * driver's device.
1209  * @gadget: the gadget to be added to the list
1210  *
1211  * Returns zero on success, negative errno otherwise.
1212  */
1213 int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
1214 {
1215 	return usb_add_gadget_udc_release(parent, gadget, NULL);
1216 }
1217 EXPORT_SYMBOL_GPL(usb_add_gadget_udc);
1218 
1219 static void usb_gadget_remove_driver(struct usb_udc *udc)
1220 {
1221 	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
1222 			udc->driver->function);
1223 
1224 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
1225 
1226 	usb_gadget_disconnect(udc->gadget);
1227 	udc->driver->disconnect(udc->gadget);
1228 	udc->driver->unbind(udc->gadget);
1229 	usb_gadget_udc_stop(udc);
1230 
1231 	udc->driver = NULL;
1232 	udc->dev.driver = NULL;
1233 	udc->gadget->dev.driver = NULL;
1234 }
1235 
1236 /**
1237  * usb_del_gadget_udc - deletes @udc from udc_list
1238  * @gadget: the gadget to be removed.
1239  *
1240  * This, will call usb_gadget_unregister_driver() if
1241  * the @udc is still busy.
1242  */
1243 void usb_del_gadget_udc(struct usb_gadget *gadget)
1244 {
1245 	struct usb_udc *udc = gadget->udc;
1246 
1247 	if (!udc)
1248 		return;
1249 
1250 	dev_vdbg(gadget->dev.parent, "unregistering gadget\n");
1251 
1252 	mutex_lock(&udc_lock);
1253 	list_del(&udc->list);
1254 
1255 	if (udc->driver) {
1256 		struct usb_gadget_driver *driver = udc->driver;
1257 
1258 		usb_gadget_remove_driver(udc);
1259 		list_add(&driver->pending, &gadget_driver_pending_list);
1260 	}
1261 	mutex_unlock(&udc_lock);
1262 
1263 	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
1264 	flush_work(&gadget->work);
1265 	device_unregister(&udc->dev);
1266 	device_unregister(&gadget->dev);
1267 }
1268 EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
1269 
1270 /* ------------------------------------------------------------------------- */
1271 
1272 static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
1273 {
1274 	int ret;
1275 
1276 	dev_dbg(&udc->dev, "registering UDC driver [%s]\n",
1277 			driver->function);
1278 
1279 	udc->driver = driver;
1280 	udc->dev.driver = &driver->driver;
1281 	udc->gadget->dev.driver = &driver->driver;
1282 
1283 	ret = driver->bind(udc->gadget, driver);
1284 	if (ret)
1285 		goto err1;
1286 	ret = usb_gadget_udc_start(udc);
1287 	if (ret) {
1288 		driver->unbind(udc->gadget);
1289 		goto err1;
1290 	}
1291 	usb_udc_connect_control(udc);
1292 
1293 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
1294 	return 0;
1295 err1:
1296 	if (ret != -EISNAM)
1297 		dev_err(&udc->dev, "failed to start %s: %d\n",
1298 			udc->driver->function, ret);
1299 	udc->driver = NULL;
1300 	udc->dev.driver = NULL;
1301 	udc->gadget->dev.driver = NULL;
1302 	return ret;
1303 }
1304 
1305 int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
1306 {
1307 	struct usb_udc		*udc = NULL;
1308 	int			ret = -ENODEV;
1309 
1310 	if (!driver || !driver->bind || !driver->setup)
1311 		return -EINVAL;
1312 
1313 	mutex_lock(&udc_lock);
1314 	if (driver->udc_name) {
1315 		list_for_each_entry(udc, &udc_list, list) {
1316 			ret = strcmp(driver->udc_name, dev_name(&udc->dev));
1317 			if (!ret)
1318 				break;
1319 		}
1320 		if (ret)
1321 			ret = -ENODEV;
1322 		else if (udc->driver)
1323 			ret = -EBUSY;
1324 		else
1325 			goto found;
1326 	} else {
1327 		list_for_each_entry(udc, &udc_list, list) {
1328 			/* For now we take the first one */
1329 			if (!udc->driver)
1330 				goto found;
1331 		}
1332 	}
1333 
1334 	if (!driver->match_existing_only) {
1335 		list_add_tail(&driver->pending, &gadget_driver_pending_list);
1336 		pr_info("udc-core: couldn't find an available UDC - added [%s] to list of pending drivers\n",
1337 			driver->function);
1338 		ret = 0;
1339 	}
1340 
1341 	mutex_unlock(&udc_lock);
1342 	return ret;
1343 found:
1344 	ret = udc_bind_to_driver(udc, driver);
1345 	mutex_unlock(&udc_lock);
1346 	return ret;
1347 }
1348 EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);
1349 
1350 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
1351 {
1352 	struct usb_udc		*udc = NULL;
1353 	int			ret = -ENODEV;
1354 
1355 	if (!driver || !driver->unbind)
1356 		return -EINVAL;
1357 
1358 	mutex_lock(&udc_lock);
1359 	list_for_each_entry(udc, &udc_list, list)
1360 		if (udc->driver == driver) {
1361 			usb_gadget_remove_driver(udc);
1362 			usb_gadget_set_state(udc->gadget,
1363 					USB_STATE_NOTATTACHED);
1364 			ret = 0;
1365 			break;
1366 		}
1367 
1368 	if (ret) {
1369 		list_del(&driver->pending);
1370 		ret = 0;
1371 	}
1372 	mutex_unlock(&udc_lock);
1373 	return ret;
1374 }
1375 EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);
1376 
1377 /* ------------------------------------------------------------------------- */
1378 
1379 static ssize_t usb_udc_srp_store(struct device *dev,
1380 		struct device_attribute *attr, const char *buf, size_t n)
1381 {
1382 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
1383 
1384 	if (sysfs_streq(buf, "1"))
1385 		usb_gadget_wakeup(udc->gadget);
1386 
1387 	return n;
1388 }
1389 static DEVICE_ATTR(srp, S_IWUSR, NULL, usb_udc_srp_store);
1390 
1391 static ssize_t usb_udc_softconn_store(struct device *dev,
1392 		struct device_attribute *attr, const char *buf, size_t n)
1393 {
1394 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
1395 
1396 	if (!udc->driver) {
1397 		dev_err(dev, "soft-connect without a gadget driver\n");
1398 		return -EOPNOTSUPP;
1399 	}
1400 
1401 	if (sysfs_streq(buf, "connect")) {
1402 		usb_gadget_udc_start(udc);
1403 		usb_gadget_connect(udc->gadget);
1404 	} else if (sysfs_streq(buf, "disconnect")) {
1405 		usb_gadget_disconnect(udc->gadget);
1406 		udc->driver->disconnect(udc->gadget);
1407 		usb_gadget_udc_stop(udc);
1408 	} else {
1409 		dev_err(dev, "unsupported command '%s'\n", buf);
1410 		return -EINVAL;
1411 	}
1412 
1413 	return n;
1414 }
1415 static DEVICE_ATTR(soft_connect, S_IWUSR, NULL, usb_udc_softconn_store);
1416 
1417 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
1418 			  char *buf)
1419 {
1420 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
1421 	struct usb_gadget	*gadget = udc->gadget;
1422 
1423 	return sprintf(buf, "%s\n", usb_state_string(gadget->state));
1424 }
1425 static DEVICE_ATTR_RO(state);
1426 
1427 #define USB_UDC_SPEED_ATTR(name, param)					\
1428 ssize_t name##_show(struct device *dev,					\
1429 		struct device_attribute *attr, char *buf)		\
1430 {									\
1431 	struct usb_udc *udc = container_of(dev, struct usb_udc, dev);	\
1432 	return snprintf(buf, PAGE_SIZE, "%s\n",				\
1433 			usb_speed_string(udc->gadget->param));		\
1434 }									\
1435 static DEVICE_ATTR_RO(name)
1436 
1437 static USB_UDC_SPEED_ATTR(current_speed, speed);
1438 static USB_UDC_SPEED_ATTR(maximum_speed, max_speed);
1439 
1440 #define USB_UDC_ATTR(name)					\
1441 ssize_t name##_show(struct device *dev,				\
1442 		struct device_attribute *attr, char *buf)	\
1443 {								\
1444 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev); \
1445 	struct usb_gadget	*gadget = udc->gadget;		\
1446 								\
1447 	return snprintf(buf, PAGE_SIZE, "%d\n", gadget->name);	\
1448 }								\
1449 static DEVICE_ATTR_RO(name)
1450 
1451 static USB_UDC_ATTR(is_otg);
1452 static USB_UDC_ATTR(is_a_peripheral);
1453 static USB_UDC_ATTR(b_hnp_enable);
1454 static USB_UDC_ATTR(a_hnp_support);
1455 static USB_UDC_ATTR(a_alt_hnp_support);
1456 static USB_UDC_ATTR(is_selfpowered);
1457 
1458 static struct attribute *usb_udc_attrs[] = {
1459 	&dev_attr_srp.attr,
1460 	&dev_attr_soft_connect.attr,
1461 	&dev_attr_state.attr,
1462 	&dev_attr_current_speed.attr,
1463 	&dev_attr_maximum_speed.attr,
1464 
1465 	&dev_attr_is_otg.attr,
1466 	&dev_attr_is_a_peripheral.attr,
1467 	&dev_attr_b_hnp_enable.attr,
1468 	&dev_attr_a_hnp_support.attr,
1469 	&dev_attr_a_alt_hnp_support.attr,
1470 	&dev_attr_is_selfpowered.attr,
1471 	NULL,
1472 };
1473 
1474 static const struct attribute_group usb_udc_attr_group = {
1475 	.attrs = usb_udc_attrs,
1476 };
1477 
1478 static const struct attribute_group *usb_udc_attr_groups[] = {
1479 	&usb_udc_attr_group,
1480 	NULL,
1481 };
1482 
1483 static int usb_udc_uevent(struct device *dev, struct kobj_uevent_env *env)
1484 {
1485 	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
1486 	int			ret;
1487 
1488 	ret = add_uevent_var(env, "USB_UDC_NAME=%s", udc->gadget->name);
1489 	if (ret) {
1490 		dev_err(dev, "failed to add uevent USB_UDC_NAME\n");
1491 		return ret;
1492 	}
1493 
1494 	if (udc->driver) {
1495 		ret = add_uevent_var(env, "USB_UDC_DRIVER=%s",
1496 				udc->driver->function);
1497 		if (ret) {
1498 			dev_err(dev, "failed to add uevent USB_UDC_DRIVER\n");
1499 			return ret;
1500 		}
1501 	}
1502 
1503 	return 0;
1504 }
1505 
1506 static int __init usb_udc_init(void)
1507 {
1508 	udc_class = class_create(THIS_MODULE, "udc");
1509 	if (IS_ERR(udc_class)) {
1510 		pr_err("failed to create udc class --> %ld\n",
1511 				PTR_ERR(udc_class));
1512 		return PTR_ERR(udc_class);
1513 	}
1514 
1515 	udc_class->dev_uevent = usb_udc_uevent;
1516 	return 0;
1517 }
1518 subsys_initcall(usb_udc_init);
1519 
1520 static void __exit usb_udc_exit(void)
1521 {
1522 	class_destroy(udc_class);
1523 }
1524 module_exit(usb_udc_exit);
1525 
1526 MODULE_DESCRIPTION("UDC Framework");
1527 MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
1528 MODULE_LICENSE("GPL v2");
1529