1 /*
2  *	uvc_gadget.c  --  USB Video Class Gadget driver
3  *
4  *	Copyright (C) 2009-2010
5  *	    Laurent Pinchart (laurent.pinchart@ideasonboard.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 as published by
9  *	the Free Software Foundation; either version 2 of the License, or
10  *	(at your option) any later version.
11  */
12 
13 #include <linux/kernel.h>
14 #include <linux/device.h>
15 #include <linux/errno.h>
16 #include <linux/fs.h>
17 #include <linux/list.h>
18 #include <linux/mutex.h>
19 #include <linux/string.h>
20 #include <linux/usb/ch9.h>
21 #include <linux/usb/gadget.h>
22 #include <linux/usb/video.h>
23 #include <linux/vmalloc.h>
24 #include <linux/wait.h>
25 
26 #include <media/v4l2-dev.h>
27 #include <media/v4l2-event.h>
28 
29 #include "uvc.h"
30 
31 unsigned int uvc_gadget_trace_param;
32 
33 /*-------------------------------------------------------------------------*/
34 
35 /* module parameters specific to the Video streaming endpoint */
36 static unsigned int streaming_interval = 1;
37 module_param(streaming_interval, uint, S_IRUGO|S_IWUSR);
38 MODULE_PARM_DESC(streaming_interval, "1 - 16");
39 
40 static unsigned int streaming_maxpacket = 1024;
41 module_param(streaming_maxpacket, uint, S_IRUGO|S_IWUSR);
42 MODULE_PARM_DESC(streaming_maxpacket, "1 - 1023 (FS), 1 - 3072 (hs/ss)");
43 
44 static unsigned int streaming_maxburst;
45 module_param(streaming_maxburst, uint, S_IRUGO|S_IWUSR);
46 MODULE_PARM_DESC(streaming_maxburst, "0 - 15 (ss only)");
47 
48 /* --------------------------------------------------------------------------
49  * Function descriptors
50  */
51 
52 /* string IDs are assigned dynamically */
53 
54 #define UVC_STRING_CONTROL_IDX			0
55 #define UVC_STRING_STREAMING_IDX		1
56 
57 static struct usb_string uvc_en_us_strings[] = {
58 	[UVC_STRING_CONTROL_IDX].s = "UVC Camera",
59 	[UVC_STRING_STREAMING_IDX].s = "Video Streaming",
60 	{  }
61 };
62 
63 static struct usb_gadget_strings uvc_stringtab = {
64 	.language = 0x0409,	/* en-us */
65 	.strings = uvc_en_us_strings,
66 };
67 
68 static struct usb_gadget_strings *uvc_function_strings[] = {
69 	&uvc_stringtab,
70 	NULL,
71 };
72 
73 #define UVC_INTF_VIDEO_CONTROL			0
74 #define UVC_INTF_VIDEO_STREAMING		1
75 
76 #define UVC_STATUS_MAX_PACKET_SIZE		16	/* 16 bytes status */
77 
78 static struct usb_interface_assoc_descriptor uvc_iad __initdata = {
79 	.bLength		= sizeof(uvc_iad),
80 	.bDescriptorType	= USB_DT_INTERFACE_ASSOCIATION,
81 	.bFirstInterface	= 0,
82 	.bInterfaceCount	= 2,
83 	.bFunctionClass		= USB_CLASS_VIDEO,
84 	.bFunctionSubClass	= UVC_SC_VIDEO_INTERFACE_COLLECTION,
85 	.bFunctionProtocol	= 0x00,
86 	.iFunction		= 0,
87 };
88 
89 static struct usb_interface_descriptor uvc_control_intf __initdata = {
90 	.bLength		= USB_DT_INTERFACE_SIZE,
91 	.bDescriptorType	= USB_DT_INTERFACE,
92 	.bInterfaceNumber	= UVC_INTF_VIDEO_CONTROL,
93 	.bAlternateSetting	= 0,
94 	.bNumEndpoints		= 1,
95 	.bInterfaceClass	= USB_CLASS_VIDEO,
96 	.bInterfaceSubClass	= UVC_SC_VIDEOCONTROL,
97 	.bInterfaceProtocol	= 0x00,
98 	.iInterface		= 0,
99 };
100 
101 static struct usb_endpoint_descriptor uvc_control_ep __initdata = {
102 	.bLength		= USB_DT_ENDPOINT_SIZE,
103 	.bDescriptorType	= USB_DT_ENDPOINT,
104 	.bEndpointAddress	= USB_DIR_IN,
105 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
106 	.wMaxPacketSize		= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
107 	.bInterval		= 8,
108 };
109 
110 static struct usb_ss_ep_comp_descriptor uvc_ss_control_comp __initdata = {
111 	.bLength		= sizeof(uvc_ss_control_comp),
112 	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
113 	/* The following 3 values can be tweaked if necessary. */
114 	.bMaxBurst		= 0,
115 	.bmAttributes		= 0,
116 	.wBytesPerInterval	= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
117 };
118 
119 static struct uvc_control_endpoint_descriptor uvc_control_cs_ep __initdata = {
120 	.bLength		= UVC_DT_CONTROL_ENDPOINT_SIZE,
121 	.bDescriptorType	= USB_DT_CS_ENDPOINT,
122 	.bDescriptorSubType	= UVC_EP_INTERRUPT,
123 	.wMaxTransferSize	= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
124 };
125 
126 static struct usb_interface_descriptor uvc_streaming_intf_alt0 __initdata = {
127 	.bLength		= USB_DT_INTERFACE_SIZE,
128 	.bDescriptorType	= USB_DT_INTERFACE,
129 	.bInterfaceNumber	= UVC_INTF_VIDEO_STREAMING,
130 	.bAlternateSetting	= 0,
131 	.bNumEndpoints		= 0,
132 	.bInterfaceClass	= USB_CLASS_VIDEO,
133 	.bInterfaceSubClass	= UVC_SC_VIDEOSTREAMING,
134 	.bInterfaceProtocol	= 0x00,
135 	.iInterface		= 0,
136 };
137 
138 static struct usb_interface_descriptor uvc_streaming_intf_alt1 __initdata = {
139 	.bLength		= USB_DT_INTERFACE_SIZE,
140 	.bDescriptorType	= USB_DT_INTERFACE,
141 	.bInterfaceNumber	= UVC_INTF_VIDEO_STREAMING,
142 	.bAlternateSetting	= 1,
143 	.bNumEndpoints		= 1,
144 	.bInterfaceClass	= USB_CLASS_VIDEO,
145 	.bInterfaceSubClass	= UVC_SC_VIDEOSTREAMING,
146 	.bInterfaceProtocol	= 0x00,
147 	.iInterface		= 0,
148 };
149 
150 static struct usb_endpoint_descriptor uvc_fs_streaming_ep __initdata = {
151 	.bLength		= USB_DT_ENDPOINT_SIZE,
152 	.bDescriptorType	= USB_DT_ENDPOINT,
153 	.bEndpointAddress	= USB_DIR_IN,
154 	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
155 				| USB_ENDPOINT_XFER_ISOC,
156 	/* The wMaxPacketSize and bInterval values will be initialized from
157 	 * module parameters.
158 	 */
159 };
160 
161 static struct usb_endpoint_descriptor uvc_hs_streaming_ep __initdata = {
162 	.bLength		= USB_DT_ENDPOINT_SIZE,
163 	.bDescriptorType	= USB_DT_ENDPOINT,
164 	.bEndpointAddress	= USB_DIR_IN,
165 	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
166 				| USB_ENDPOINT_XFER_ISOC,
167 	/* The wMaxPacketSize and bInterval values will be initialized from
168 	 * module parameters.
169 	 */
170 };
171 
172 static struct usb_endpoint_descriptor uvc_ss_streaming_ep __initdata = {
173 	.bLength		= USB_DT_ENDPOINT_SIZE,
174 	.bDescriptorType	= USB_DT_ENDPOINT,
175 
176 	.bEndpointAddress	= USB_DIR_IN,
177 	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
178 				| USB_ENDPOINT_XFER_ISOC,
179 	/* The wMaxPacketSize and bInterval values will be initialized from
180 	 * module parameters.
181 	 */
182 };
183 
184 static struct usb_ss_ep_comp_descriptor uvc_ss_streaming_comp __initdata = {
185 	.bLength		= sizeof(uvc_ss_streaming_comp),
186 	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
187 	/* The bMaxBurst, bmAttributes and wBytesPerInterval values will be
188 	 * initialized from module parameters.
189 	 */
190 };
191 
192 static const struct usb_descriptor_header * const uvc_fs_streaming[] = {
193 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
194 	(struct usb_descriptor_header *) &uvc_fs_streaming_ep,
195 	NULL,
196 };
197 
198 static const struct usb_descriptor_header * const uvc_hs_streaming[] = {
199 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
200 	(struct usb_descriptor_header *) &uvc_hs_streaming_ep,
201 	NULL,
202 };
203 
204 static const struct usb_descriptor_header * const uvc_ss_streaming[] = {
205 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
206 	(struct usb_descriptor_header *) &uvc_ss_streaming_ep,
207 	(struct usb_descriptor_header *) &uvc_ss_streaming_comp,
208 	NULL,
209 };
210 
211 /* --------------------------------------------------------------------------
212  * Control requests
213  */
214 
215 static void
216 uvc_function_ep0_complete(struct usb_ep *ep, struct usb_request *req)
217 {
218 	struct uvc_device *uvc = req->context;
219 	struct v4l2_event v4l2_event;
220 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
221 
222 	if (uvc->event_setup_out) {
223 		uvc->event_setup_out = 0;
224 
225 		memset(&v4l2_event, 0, sizeof(v4l2_event));
226 		v4l2_event.type = UVC_EVENT_DATA;
227 		uvc_event->data.length = req->actual;
228 		memcpy(&uvc_event->data.data, req->buf, req->actual);
229 		v4l2_event_queue(uvc->vdev, &v4l2_event);
230 	}
231 }
232 
233 static int
234 uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
235 {
236 	struct uvc_device *uvc = to_uvc(f);
237 	struct v4l2_event v4l2_event;
238 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
239 
240 	/* printk(KERN_INFO "setup request %02x %02x value %04x index %04x %04x\n",
241 	 *	ctrl->bRequestType, ctrl->bRequest, le16_to_cpu(ctrl->wValue),
242 	 *	le16_to_cpu(ctrl->wIndex), le16_to_cpu(ctrl->wLength));
243 	 */
244 
245 	if ((ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS) {
246 		INFO(f->config->cdev, "invalid request type\n");
247 		return -EINVAL;
248 	}
249 
250 	/* Stall too big requests. */
251 	if (le16_to_cpu(ctrl->wLength) > UVC_MAX_REQUEST_SIZE)
252 		return -EINVAL;
253 
254 	memset(&v4l2_event, 0, sizeof(v4l2_event));
255 	v4l2_event.type = UVC_EVENT_SETUP;
256 	memcpy(&uvc_event->req, ctrl, sizeof(uvc_event->req));
257 	v4l2_event_queue(uvc->vdev, &v4l2_event);
258 
259 	return 0;
260 }
261 
262 void uvc_function_setup_continue(struct uvc_device *uvc)
263 {
264 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
265 
266 	usb_composite_setup_continue(cdev);
267 }
268 
269 static int
270 uvc_function_get_alt(struct usb_function *f, unsigned interface)
271 {
272 	struct uvc_device *uvc = to_uvc(f);
273 
274 	INFO(f->config->cdev, "uvc_function_get_alt(%u)\n", interface);
275 
276 	if (interface == uvc->control_intf)
277 		return 0;
278 	else if (interface != uvc->streaming_intf)
279 		return -EINVAL;
280 	else
281 		return uvc->state == UVC_STATE_STREAMING ? 1 : 0;
282 }
283 
284 static int
285 uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
286 {
287 	struct uvc_device *uvc = to_uvc(f);
288 	struct v4l2_event v4l2_event;
289 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
290 	int ret;
291 
292 	INFO(f->config->cdev, "uvc_function_set_alt(%u, %u)\n", interface, alt);
293 
294 	if (interface == uvc->control_intf) {
295 		if (alt)
296 			return -EINVAL;
297 
298 		if (uvc->state == UVC_STATE_DISCONNECTED) {
299 			memset(&v4l2_event, 0, sizeof(v4l2_event));
300 			v4l2_event.type = UVC_EVENT_CONNECT;
301 			uvc_event->speed = f->config->cdev->gadget->speed;
302 			v4l2_event_queue(uvc->vdev, &v4l2_event);
303 
304 			uvc->state = UVC_STATE_CONNECTED;
305 		}
306 
307 		return 0;
308 	}
309 
310 	if (interface != uvc->streaming_intf)
311 		return -EINVAL;
312 
313 	/* TODO
314 	if (usb_endpoint_xfer_bulk(&uvc->desc.vs_ep))
315 		return alt ? -EINVAL : 0;
316 	*/
317 
318 	switch (alt) {
319 	case 0:
320 		if (uvc->state != UVC_STATE_STREAMING)
321 			return 0;
322 
323 		if (uvc->video.ep)
324 			usb_ep_disable(uvc->video.ep);
325 
326 		memset(&v4l2_event, 0, sizeof(v4l2_event));
327 		v4l2_event.type = UVC_EVENT_STREAMOFF;
328 		v4l2_event_queue(uvc->vdev, &v4l2_event);
329 
330 		uvc->state = UVC_STATE_CONNECTED;
331 		return 0;
332 
333 	case 1:
334 		if (uvc->state != UVC_STATE_CONNECTED)
335 			return 0;
336 
337 		if (uvc->video.ep) {
338 			ret = config_ep_by_speed(f->config->cdev->gadget,
339 					&(uvc->func), uvc->video.ep);
340 			if (ret)
341 				return ret;
342 			usb_ep_enable(uvc->video.ep);
343 		}
344 
345 		memset(&v4l2_event, 0, sizeof(v4l2_event));
346 		v4l2_event.type = UVC_EVENT_STREAMON;
347 		v4l2_event_queue(uvc->vdev, &v4l2_event);
348 		return USB_GADGET_DELAYED_STATUS;
349 
350 	default:
351 		return -EINVAL;
352 	}
353 }
354 
355 static void
356 uvc_function_disable(struct usb_function *f)
357 {
358 	struct uvc_device *uvc = to_uvc(f);
359 	struct v4l2_event v4l2_event;
360 
361 	INFO(f->config->cdev, "uvc_function_disable\n");
362 
363 	memset(&v4l2_event, 0, sizeof(v4l2_event));
364 	v4l2_event.type = UVC_EVENT_DISCONNECT;
365 	v4l2_event_queue(uvc->vdev, &v4l2_event);
366 
367 	uvc->state = UVC_STATE_DISCONNECTED;
368 }
369 
370 /* --------------------------------------------------------------------------
371  * Connection / disconnection
372  */
373 
374 void
375 uvc_function_connect(struct uvc_device *uvc)
376 {
377 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
378 	int ret;
379 
380 	if ((ret = usb_function_activate(&uvc->func)) < 0)
381 		INFO(cdev, "UVC connect failed with %d\n", ret);
382 }
383 
384 void
385 uvc_function_disconnect(struct uvc_device *uvc)
386 {
387 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
388 	int ret;
389 
390 	if ((ret = usb_function_deactivate(&uvc->func)) < 0)
391 		INFO(cdev, "UVC disconnect failed with %d\n", ret);
392 }
393 
394 /* --------------------------------------------------------------------------
395  * USB probe and disconnect
396  */
397 
398 static int
399 uvc_register_video(struct uvc_device *uvc)
400 {
401 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
402 	struct video_device *video;
403 
404 	/* TODO reference counting. */
405 	video = video_device_alloc();
406 	if (video == NULL)
407 		return -ENOMEM;
408 
409 	video->v4l2_dev = &uvc->v4l2_dev;
410 	video->fops = &uvc_v4l2_fops;
411 	video->release = video_device_release;
412 	strlcpy(video->name, cdev->gadget->name, sizeof(video->name));
413 
414 	uvc->vdev = video;
415 	video_set_drvdata(video, uvc);
416 
417 	return video_register_device(video, VFL_TYPE_GRABBER, -1);
418 }
419 
420 #define UVC_COPY_DESCRIPTOR(mem, dst, desc) \
421 	do { \
422 		memcpy(mem, desc, (desc)->bLength); \
423 		*(dst)++ = mem; \
424 		mem += (desc)->bLength; \
425 	} while (0);
426 
427 #define UVC_COPY_DESCRIPTORS(mem, dst, src) \
428 	do { \
429 		const struct usb_descriptor_header * const *__src; \
430 		for (__src = src; *__src; ++__src) { \
431 			memcpy(mem, *__src, (*__src)->bLength); \
432 			*dst++ = mem; \
433 			mem += (*__src)->bLength; \
434 		} \
435 	} while (0)
436 
437 static struct usb_descriptor_header ** __init
438 uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
439 {
440 	struct uvc_input_header_descriptor *uvc_streaming_header;
441 	struct uvc_header_descriptor *uvc_control_header;
442 	const struct uvc_descriptor_header * const *uvc_control_desc;
443 	const struct uvc_descriptor_header * const *uvc_streaming_cls;
444 	const struct usb_descriptor_header * const *uvc_streaming_std;
445 	const struct usb_descriptor_header * const *src;
446 	struct usb_descriptor_header **dst;
447 	struct usb_descriptor_header **hdr;
448 	unsigned int control_size;
449 	unsigned int streaming_size;
450 	unsigned int n_desc;
451 	unsigned int bytes;
452 	void *mem;
453 
454 	switch (speed) {
455 	case USB_SPEED_SUPER:
456 		uvc_control_desc = uvc->desc.ss_control;
457 		uvc_streaming_cls = uvc->desc.ss_streaming;
458 		uvc_streaming_std = uvc_ss_streaming;
459 		break;
460 
461 	case USB_SPEED_HIGH:
462 		uvc_control_desc = uvc->desc.fs_control;
463 		uvc_streaming_cls = uvc->desc.hs_streaming;
464 		uvc_streaming_std = uvc_hs_streaming;
465 		break;
466 
467 	case USB_SPEED_FULL:
468 	default:
469 		uvc_control_desc = uvc->desc.fs_control;
470 		uvc_streaming_cls = uvc->desc.fs_streaming;
471 		uvc_streaming_std = uvc_fs_streaming;
472 		break;
473 	}
474 
475 	/* Descriptors layout
476 	 *
477 	 * uvc_iad
478 	 * uvc_control_intf
479 	 * Class-specific UVC control descriptors
480 	 * uvc_control_ep
481 	 * uvc_control_cs_ep
482 	 * uvc_ss_control_comp (for SS only)
483 	 * uvc_streaming_intf_alt0
484 	 * Class-specific UVC streaming descriptors
485 	 * uvc_{fs|hs}_streaming
486 	 */
487 
488 	/* Count descriptors and compute their size. */
489 	control_size = 0;
490 	streaming_size = 0;
491 	bytes = uvc_iad.bLength + uvc_control_intf.bLength
492 	      + uvc_control_ep.bLength + uvc_control_cs_ep.bLength
493 	      + uvc_streaming_intf_alt0.bLength;
494 
495 	if (speed == USB_SPEED_SUPER) {
496 		bytes += uvc_ss_control_comp.bLength;
497 		n_desc = 6;
498 	} else {
499 		n_desc = 5;
500 	}
501 
502 	for (src = (const struct usb_descriptor_header **)uvc_control_desc;
503 	     *src; ++src) {
504 		control_size += (*src)->bLength;
505 		bytes += (*src)->bLength;
506 		n_desc++;
507 	}
508 	for (src = (const struct usb_descriptor_header **)uvc_streaming_cls;
509 	     *src; ++src) {
510 		streaming_size += (*src)->bLength;
511 		bytes += (*src)->bLength;
512 		n_desc++;
513 	}
514 	for (src = uvc_streaming_std; *src; ++src) {
515 		bytes += (*src)->bLength;
516 		n_desc++;
517 	}
518 
519 	mem = kmalloc((n_desc + 1) * sizeof(*src) + bytes, GFP_KERNEL);
520 	if (mem == NULL)
521 		return NULL;
522 
523 	hdr = mem;
524 	dst = mem;
525 	mem += (n_desc + 1) * sizeof(*src);
526 
527 	/* Copy the descriptors. */
528 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_iad);
529 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_intf);
530 
531 	uvc_control_header = mem;
532 	UVC_COPY_DESCRIPTORS(mem, dst,
533 		(const struct usb_descriptor_header **)uvc_control_desc);
534 	uvc_control_header->wTotalLength = cpu_to_le16(control_size);
535 	uvc_control_header->bInCollection = 1;
536 	uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;
537 
538 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_ep);
539 	if (speed == USB_SPEED_SUPER)
540 		UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp);
541 
542 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_cs_ep);
543 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_streaming_intf_alt0);
544 
545 	uvc_streaming_header = mem;
546 	UVC_COPY_DESCRIPTORS(mem, dst,
547 		(const struct usb_descriptor_header**)uvc_streaming_cls);
548 	uvc_streaming_header->wTotalLength = cpu_to_le16(streaming_size);
549 	uvc_streaming_header->bEndpointAddress = uvc->video.ep->address;
550 
551 	UVC_COPY_DESCRIPTORS(mem, dst, uvc_streaming_std);
552 
553 	*dst = NULL;
554 	return hdr;
555 }
556 
557 static void
558 uvc_function_unbind(struct usb_configuration *c, struct usb_function *f)
559 {
560 	struct usb_composite_dev *cdev = c->cdev;
561 	struct uvc_device *uvc = to_uvc(f);
562 
563 	INFO(cdev, "uvc_function_unbind\n");
564 
565 	video_unregister_device(uvc->vdev);
566 	v4l2_device_unregister(&uvc->v4l2_dev);
567 	uvc->control_ep->driver_data = NULL;
568 	uvc->video.ep->driver_data = NULL;
569 
570 	uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id = 0;
571 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
572 	kfree(uvc->control_buf);
573 
574 	usb_free_all_descriptors(f);
575 
576 	kfree(uvc);
577 }
578 
579 static int __init
580 uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
581 {
582 	struct usb_composite_dev *cdev = c->cdev;
583 	struct uvc_device *uvc = to_uvc(f);
584 	unsigned int max_packet_mult;
585 	unsigned int max_packet_size;
586 	struct usb_ep *ep;
587 	int ret = -EINVAL;
588 
589 	INFO(cdev, "uvc_function_bind\n");
590 
591 	/* Sanity check the streaming endpoint module parameters.
592 	 */
593 	streaming_interval = clamp(streaming_interval, 1U, 16U);
594 	streaming_maxpacket = clamp(streaming_maxpacket, 1U, 3072U);
595 	streaming_maxburst = min(streaming_maxburst, 15U);
596 
597 	/* Fill in the FS/HS/SS Video Streaming specific descriptors from the
598 	 * module parameters.
599 	 *
600 	 * NOTE: We assume that the user knows what they are doing and won't
601 	 * give parameters that their UDC doesn't support.
602 	 */
603 	if (streaming_maxpacket <= 1024) {
604 		max_packet_mult = 1;
605 		max_packet_size = streaming_maxpacket;
606 	} else if (streaming_maxpacket <= 2048) {
607 		max_packet_mult = 2;
608 		max_packet_size = streaming_maxpacket / 2;
609 	} else {
610 		max_packet_mult = 3;
611 		max_packet_size = streaming_maxpacket / 3;
612 	}
613 
614 	uvc_fs_streaming_ep.wMaxPacketSize = min(streaming_maxpacket, 1023U);
615 	uvc_fs_streaming_ep.bInterval = streaming_interval;
616 
617 	uvc_hs_streaming_ep.wMaxPacketSize = max_packet_size;
618 	uvc_hs_streaming_ep.wMaxPacketSize |= ((max_packet_mult - 1) << 11);
619 	uvc_hs_streaming_ep.bInterval = streaming_interval;
620 
621 	uvc_ss_streaming_ep.wMaxPacketSize = max_packet_size;
622 	uvc_ss_streaming_ep.bInterval = streaming_interval;
623 	uvc_ss_streaming_comp.bmAttributes = max_packet_mult - 1;
624 	uvc_ss_streaming_comp.bMaxBurst = streaming_maxburst;
625 	uvc_ss_streaming_comp.wBytesPerInterval =
626 		max_packet_size * max_packet_mult * streaming_maxburst;
627 
628 	/* Allocate endpoints. */
629 	ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);
630 	if (!ep) {
631 		INFO(cdev, "Unable to allocate control EP\n");
632 		goto error;
633 	}
634 	uvc->control_ep = ep;
635 	ep->driver_data = uvc;
636 
637 	if (gadget_is_superspeed(c->cdev->gadget))
638 		ep = usb_ep_autoconfig_ss(cdev->gadget, &uvc_ss_streaming_ep,
639 					  &uvc_ss_streaming_comp);
640 	else if (gadget_is_dualspeed(cdev->gadget))
641 		ep = usb_ep_autoconfig(cdev->gadget, &uvc_hs_streaming_ep);
642 	else
643 		ep = usb_ep_autoconfig(cdev->gadget, &uvc_fs_streaming_ep);
644 
645 	if (!ep) {
646 		INFO(cdev, "Unable to allocate streaming EP\n");
647 		goto error;
648 	}
649 	uvc->video.ep = ep;
650 	ep->driver_data = uvc;
651 
652 	uvc_fs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
653 	uvc_hs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
654 	uvc_ss_streaming_ep.bEndpointAddress = uvc->video.ep->address;
655 
656 	/* Allocate interface IDs. */
657 	if ((ret = usb_interface_id(c, f)) < 0)
658 		goto error;
659 	uvc_iad.bFirstInterface = ret;
660 	uvc_control_intf.bInterfaceNumber = ret;
661 	uvc->control_intf = ret;
662 
663 	if ((ret = usb_interface_id(c, f)) < 0)
664 		goto error;
665 	uvc_streaming_intf_alt0.bInterfaceNumber = ret;
666 	uvc_streaming_intf_alt1.bInterfaceNumber = ret;
667 	uvc->streaming_intf = ret;
668 
669 	/* Copy descriptors */
670 	f->fs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);
671 	if (gadget_is_dualspeed(cdev->gadget))
672 		f->hs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_HIGH);
673 	if (gadget_is_superspeed(c->cdev->gadget))
674 		f->ss_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_SUPER);
675 
676 	/* Preallocate control endpoint request. */
677 	uvc->control_req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
678 	uvc->control_buf = kmalloc(UVC_MAX_REQUEST_SIZE, GFP_KERNEL);
679 	if (uvc->control_req == NULL || uvc->control_buf == NULL) {
680 		ret = -ENOMEM;
681 		goto error;
682 	}
683 
684 	uvc->control_req->buf = uvc->control_buf;
685 	uvc->control_req->complete = uvc_function_ep0_complete;
686 	uvc->control_req->context = uvc;
687 
688 	/* Avoid letting this gadget enumerate until the userspace server is
689 	 * active.
690 	 */
691 	if ((ret = usb_function_deactivate(f)) < 0)
692 		goto error;
693 
694 	if (v4l2_device_register(&cdev->gadget->dev, &uvc->v4l2_dev)) {
695 		printk(KERN_INFO "v4l2_device_register failed\n");
696 		goto error;
697 	}
698 
699 	/* Initialise video. */
700 	ret = uvc_video_init(&uvc->video);
701 	if (ret < 0)
702 		goto error;
703 
704 	/* Register a V4L2 device. */
705 	ret = uvc_register_video(uvc);
706 	if (ret < 0) {
707 		printk(KERN_INFO "Unable to register video device\n");
708 		goto error;
709 	}
710 
711 	return 0;
712 
713 error:
714 	v4l2_device_unregister(&uvc->v4l2_dev);
715 	if (uvc->vdev)
716 		video_device_release(uvc->vdev);
717 
718 	if (uvc->control_ep)
719 		uvc->control_ep->driver_data = NULL;
720 	if (uvc->video.ep)
721 		uvc->video.ep->driver_data = NULL;
722 
723 	if (uvc->control_req) {
724 		usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
725 		kfree(uvc->control_buf);
726 	}
727 
728 	usb_free_all_descriptors(f);
729 	return ret;
730 }
731 
732 /* --------------------------------------------------------------------------
733  * USB gadget function
734  */
735 
736 /**
737  * uvc_bind_config - add a UVC function to a configuration
738  * @c: the configuration to support the UVC instance
739  * Context: single threaded during gadget setup
740  *
741  * Returns zero on success, else negative errno.
742  *
743  * Caller must have called @uvc_setup(). Caller is also responsible for
744  * calling @uvc_cleanup() before module unload.
745  */
746 int __init
747 uvc_bind_config(struct usb_configuration *c,
748 		const struct uvc_descriptor_header * const *fs_control,
749 		const struct uvc_descriptor_header * const *ss_control,
750 		const struct uvc_descriptor_header * const *fs_streaming,
751 		const struct uvc_descriptor_header * const *hs_streaming,
752 		const struct uvc_descriptor_header * const *ss_streaming)
753 {
754 	struct uvc_device *uvc;
755 	int ret = 0;
756 
757 	/* TODO Check if the USB device controller supports the required
758 	 * features.
759 	 */
760 	if (!gadget_is_dualspeed(c->cdev->gadget))
761 		return -EINVAL;
762 
763 	uvc = kzalloc(sizeof(*uvc), GFP_KERNEL);
764 	if (uvc == NULL)
765 		return -ENOMEM;
766 
767 	uvc->state = UVC_STATE_DISCONNECTED;
768 
769 	/* Validate the descriptors. */
770 	if (fs_control == NULL || fs_control[0] == NULL ||
771 	    fs_control[0]->bDescriptorSubType != UVC_VC_HEADER)
772 		goto error;
773 
774 	if (ss_control == NULL || ss_control[0] == NULL ||
775 	    ss_control[0]->bDescriptorSubType != UVC_VC_HEADER)
776 		goto error;
777 
778 	if (fs_streaming == NULL || fs_streaming[0] == NULL ||
779 	    fs_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
780 		goto error;
781 
782 	if (hs_streaming == NULL || hs_streaming[0] == NULL ||
783 	    hs_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
784 		goto error;
785 
786 	if (ss_streaming == NULL || ss_streaming[0] == NULL ||
787 	    ss_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
788 		goto error;
789 
790 	uvc->desc.fs_control = fs_control;
791 	uvc->desc.ss_control = ss_control;
792 	uvc->desc.fs_streaming = fs_streaming;
793 	uvc->desc.hs_streaming = hs_streaming;
794 	uvc->desc.ss_streaming = ss_streaming;
795 
796 	/* String descriptors are global, we only need to allocate string IDs
797 	 * for the first UVC function. UVC functions beyond the first (if any)
798 	 * will reuse the same IDs.
799 	 */
800 	if (uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id == 0) {
801 		ret = usb_string_ids_tab(c->cdev, uvc_en_us_strings);
802 		if (ret)
803 			goto error;
804 		uvc_iad.iFunction =
805 			uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id;
806 		uvc_control_intf.iInterface =
807 			uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id;
808 		ret = uvc_en_us_strings[UVC_STRING_STREAMING_IDX].id;
809 		uvc_streaming_intf_alt0.iInterface = ret;
810 		uvc_streaming_intf_alt1.iInterface = ret;
811 	}
812 
813 	/* Register the function. */
814 	uvc->func.name = "uvc";
815 	uvc->func.strings = uvc_function_strings;
816 	uvc->func.bind = uvc_function_bind;
817 	uvc->func.unbind = uvc_function_unbind;
818 	uvc->func.get_alt = uvc_function_get_alt;
819 	uvc->func.set_alt = uvc_function_set_alt;
820 	uvc->func.disable = uvc_function_disable;
821 	uvc->func.setup = uvc_function_setup;
822 
823 	ret = usb_add_function(c, &uvc->func);
824 	if (ret)
825 		kfree(uvc);
826 
827 	return ret;
828 
829 error:
830 	kfree(uvc);
831 	return ret;
832 }
833 
834 module_param_named(trace, uvc_gadget_trace_param, uint, S_IRUGO|S_IWUSR);
835 MODULE_PARM_DESC(trace, "Trace level bitmask");
836 
837