1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *	uvc_gadget.c  --  USB Video Class Gadget driver
4  *
5  *	Copyright (C) 2009-2010
6  *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7  */
8 
9 #include <linux/device.h>
10 #include <linux/errno.h>
11 #include <linux/fs.h>
12 #include <linux/kernel.h>
13 #include <linux/list.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/string.h>
17 #include <linux/usb/ch9.h>
18 #include <linux/usb/gadget.h>
19 #include <linux/usb/g_uvc.h>
20 #include <linux/usb/video.h>
21 #include <linux/vmalloc.h>
22 #include <linux/wait.h>
23 
24 #include <media/v4l2-dev.h>
25 #include <media/v4l2-event.h>
26 
27 #include "u_uvc.h"
28 #include "uvc.h"
29 #include "uvc_configfs.h"
30 #include "uvc_v4l2.h"
31 #include "uvc_video.h"
32 
33 unsigned int uvc_gadget_trace_param;
34 module_param_named(trace, uvc_gadget_trace_param, uint, 0644);
35 MODULE_PARM_DESC(trace, "Trace level bitmask");
36 
37 /* --------------------------------------------------------------------------
38  * Function descriptors
39  */
40 
41 /* string IDs are assigned dynamically */
42 
43 #define UVC_STRING_CONTROL_IDX			0
44 #define UVC_STRING_STREAMING_IDX		1
45 
46 static struct usb_string uvc_en_us_strings[] = {
47 	[UVC_STRING_CONTROL_IDX].s = "UVC Camera",
48 	[UVC_STRING_STREAMING_IDX].s = "Video Streaming",
49 	{  }
50 };
51 
52 static struct usb_gadget_strings uvc_stringtab = {
53 	.language = 0x0409,	/* en-us */
54 	.strings = uvc_en_us_strings,
55 };
56 
57 static struct usb_gadget_strings *uvc_function_strings[] = {
58 	&uvc_stringtab,
59 	NULL,
60 };
61 
62 #define UVC_INTF_VIDEO_CONTROL			0
63 #define UVC_INTF_VIDEO_STREAMING		1
64 
65 #define UVC_STATUS_MAX_PACKET_SIZE		16	/* 16 bytes status */
66 
67 static struct usb_interface_assoc_descriptor uvc_iad = {
68 	.bLength		= sizeof(uvc_iad),
69 	.bDescriptorType	= USB_DT_INTERFACE_ASSOCIATION,
70 	.bFirstInterface	= 0,
71 	.bInterfaceCount	= 2,
72 	.bFunctionClass		= USB_CLASS_VIDEO,
73 	.bFunctionSubClass	= UVC_SC_VIDEO_INTERFACE_COLLECTION,
74 	.bFunctionProtocol	= 0x00,
75 	.iFunction		= 0,
76 };
77 
78 static struct usb_interface_descriptor uvc_control_intf = {
79 	.bLength		= USB_DT_INTERFACE_SIZE,
80 	.bDescriptorType	= USB_DT_INTERFACE,
81 	.bInterfaceNumber	= UVC_INTF_VIDEO_CONTROL,
82 	.bAlternateSetting	= 0,
83 	.bNumEndpoints		= 1,
84 	.bInterfaceClass	= USB_CLASS_VIDEO,
85 	.bInterfaceSubClass	= UVC_SC_VIDEOCONTROL,
86 	.bInterfaceProtocol	= 0x00,
87 	.iInterface		= 0,
88 };
89 
90 static struct usb_endpoint_descriptor uvc_control_ep = {
91 	.bLength		= USB_DT_ENDPOINT_SIZE,
92 	.bDescriptorType	= USB_DT_ENDPOINT,
93 	.bEndpointAddress	= USB_DIR_IN,
94 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
95 	.wMaxPacketSize		= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
96 	.bInterval		= 8,
97 };
98 
99 static struct usb_ss_ep_comp_descriptor uvc_ss_control_comp = {
100 	.bLength		= sizeof(uvc_ss_control_comp),
101 	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
102 	/* The following 3 values can be tweaked if necessary. */
103 	.bMaxBurst		= 0,
104 	.bmAttributes		= 0,
105 	.wBytesPerInterval	= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
106 };
107 
108 static struct uvc_control_endpoint_descriptor uvc_control_cs_ep = {
109 	.bLength		= UVC_DT_CONTROL_ENDPOINT_SIZE,
110 	.bDescriptorType	= USB_DT_CS_ENDPOINT,
111 	.bDescriptorSubType	= UVC_EP_INTERRUPT,
112 	.wMaxTransferSize	= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
113 };
114 
115 static struct usb_interface_descriptor uvc_streaming_intf_alt0 = {
116 	.bLength		= USB_DT_INTERFACE_SIZE,
117 	.bDescriptorType	= USB_DT_INTERFACE,
118 	.bInterfaceNumber	= UVC_INTF_VIDEO_STREAMING,
119 	.bAlternateSetting	= 0,
120 	.bNumEndpoints		= 0,
121 	.bInterfaceClass	= USB_CLASS_VIDEO,
122 	.bInterfaceSubClass	= UVC_SC_VIDEOSTREAMING,
123 	.bInterfaceProtocol	= 0x00,
124 	.iInterface		= 0,
125 };
126 
127 static struct usb_interface_descriptor uvc_streaming_intf_alt1 = {
128 	.bLength		= USB_DT_INTERFACE_SIZE,
129 	.bDescriptorType	= USB_DT_INTERFACE,
130 	.bInterfaceNumber	= UVC_INTF_VIDEO_STREAMING,
131 	.bAlternateSetting	= 1,
132 	.bNumEndpoints		= 1,
133 	.bInterfaceClass	= USB_CLASS_VIDEO,
134 	.bInterfaceSubClass	= UVC_SC_VIDEOSTREAMING,
135 	.bInterfaceProtocol	= 0x00,
136 	.iInterface		= 0,
137 };
138 
139 static struct usb_endpoint_descriptor uvc_fs_streaming_ep = {
140 	.bLength		= USB_DT_ENDPOINT_SIZE,
141 	.bDescriptorType	= USB_DT_ENDPOINT,
142 	.bEndpointAddress	= USB_DIR_IN,
143 	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
144 				| USB_ENDPOINT_XFER_ISOC,
145 	/* The wMaxPacketSize and bInterval values will be initialized from
146 	 * module parameters.
147 	 */
148 };
149 
150 static struct usb_endpoint_descriptor uvc_hs_streaming_ep = {
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_ss_streaming_ep = {
162 	.bLength		= USB_DT_ENDPOINT_SIZE,
163 	.bDescriptorType	= USB_DT_ENDPOINT,
164 
165 	.bEndpointAddress	= USB_DIR_IN,
166 	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
167 				| USB_ENDPOINT_XFER_ISOC,
168 	/* The wMaxPacketSize and bInterval values will be initialized from
169 	 * module parameters.
170 	 */
171 };
172 
173 static struct usb_ss_ep_comp_descriptor uvc_ss_streaming_comp = {
174 	.bLength		= sizeof(uvc_ss_streaming_comp),
175 	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
176 	/* The bMaxBurst, bmAttributes and wBytesPerInterval values will be
177 	 * initialized from module parameters.
178 	 */
179 };
180 
181 static const struct usb_descriptor_header * const uvc_fs_streaming[] = {
182 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
183 	(struct usb_descriptor_header *) &uvc_fs_streaming_ep,
184 	NULL,
185 };
186 
187 static const struct usb_descriptor_header * const uvc_hs_streaming[] = {
188 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
189 	(struct usb_descriptor_header *) &uvc_hs_streaming_ep,
190 	NULL,
191 };
192 
193 static const struct usb_descriptor_header * const uvc_ss_streaming[] = {
194 	(struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
195 	(struct usb_descriptor_header *) &uvc_ss_streaming_ep,
196 	(struct usb_descriptor_header *) &uvc_ss_streaming_comp,
197 	NULL,
198 };
199 
200 /* --------------------------------------------------------------------------
201  * Control requests
202  */
203 
204 static void
205 uvc_function_ep0_complete(struct usb_ep *ep, struct usb_request *req)
206 {
207 	struct uvc_device *uvc = req->context;
208 	struct v4l2_event v4l2_event;
209 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
210 
211 	if (uvc->event_setup_out) {
212 		uvc->event_setup_out = 0;
213 
214 		memset(&v4l2_event, 0, sizeof(v4l2_event));
215 		v4l2_event.type = UVC_EVENT_DATA;
216 		uvc_event->data.length = req->actual;
217 		memcpy(&uvc_event->data.data, req->buf, req->actual);
218 		v4l2_event_queue(&uvc->vdev, &v4l2_event);
219 	}
220 }
221 
222 static int
223 uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
224 {
225 	struct uvc_device *uvc = to_uvc(f);
226 	struct v4l2_event v4l2_event;
227 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
228 
229 	if ((ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS) {
230 		uvcg_info(f, "invalid request type\n");
231 		return -EINVAL;
232 	}
233 
234 	/* Stall too big requests. */
235 	if (le16_to_cpu(ctrl->wLength) > UVC_MAX_REQUEST_SIZE)
236 		return -EINVAL;
237 
238 	/* Tell the complete callback to generate an event for the next request
239 	 * that will be enqueued by UVCIOC_SEND_RESPONSE.
240 	 */
241 	uvc->event_setup_out = !(ctrl->bRequestType & USB_DIR_IN);
242 	uvc->event_length = le16_to_cpu(ctrl->wLength);
243 
244 	memset(&v4l2_event, 0, sizeof(v4l2_event));
245 	v4l2_event.type = UVC_EVENT_SETUP;
246 	memcpy(&uvc_event->req, ctrl, sizeof(uvc_event->req));
247 	v4l2_event_queue(&uvc->vdev, &v4l2_event);
248 
249 	return 0;
250 }
251 
252 void uvc_function_setup_continue(struct uvc_device *uvc)
253 {
254 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
255 
256 	usb_composite_setup_continue(cdev);
257 }
258 
259 static int
260 uvc_function_get_alt(struct usb_function *f, unsigned interface)
261 {
262 	struct uvc_device *uvc = to_uvc(f);
263 
264 	uvcg_info(f, "%s(%u)\n", __func__, interface);
265 
266 	if (interface == uvc->control_intf)
267 		return 0;
268 	else if (interface != uvc->streaming_intf)
269 		return -EINVAL;
270 	else
271 		return uvc->video.ep->enabled ? 1 : 0;
272 }
273 
274 static int
275 uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
276 {
277 	struct uvc_device *uvc = to_uvc(f);
278 	struct usb_composite_dev *cdev = f->config->cdev;
279 	struct v4l2_event v4l2_event;
280 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
281 	int ret;
282 
283 	uvcg_info(f, "%s(%u, %u)\n", __func__, interface, alt);
284 
285 	if (interface == uvc->control_intf) {
286 		if (alt)
287 			return -EINVAL;
288 
289 		uvcg_info(f, "reset UVC Control\n");
290 		usb_ep_disable(uvc->control_ep);
291 
292 		if (!uvc->control_ep->desc)
293 			if (config_ep_by_speed(cdev->gadget, f, uvc->control_ep))
294 				return -EINVAL;
295 
296 		usb_ep_enable(uvc->control_ep);
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 = 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 			return -EINVAL;
339 
340 		uvcg_info(f, "reset UVC\n");
341 		usb_ep_disable(uvc->video.ep);
342 
343 		ret = config_ep_by_speed(f->config->cdev->gadget,
344 				&(uvc->func), uvc->video.ep);
345 		if (ret)
346 			return ret;
347 		usb_ep_enable(uvc->video.ep);
348 
349 		memset(&v4l2_event, 0, sizeof(v4l2_event));
350 		v4l2_event.type = UVC_EVENT_STREAMON;
351 		v4l2_event_queue(&uvc->vdev, &v4l2_event);
352 		return USB_GADGET_DELAYED_STATUS;
353 
354 	default:
355 		return -EINVAL;
356 	}
357 }
358 
359 static void
360 uvc_function_disable(struct usb_function *f)
361 {
362 	struct uvc_device *uvc = to_uvc(f);
363 	struct v4l2_event v4l2_event;
364 
365 	uvcg_info(f, "%s()\n", __func__);
366 
367 	memset(&v4l2_event, 0, sizeof(v4l2_event));
368 	v4l2_event.type = UVC_EVENT_DISCONNECT;
369 	v4l2_event_queue(&uvc->vdev, &v4l2_event);
370 
371 	uvc->state = UVC_STATE_DISCONNECTED;
372 
373 	usb_ep_disable(uvc->video.ep);
374 	usb_ep_disable(uvc->control_ep);
375 }
376 
377 /* --------------------------------------------------------------------------
378  * Connection / disconnection
379  */
380 
381 void
382 uvc_function_connect(struct uvc_device *uvc)
383 {
384 	int ret;
385 
386 	if ((ret = usb_function_activate(&uvc->func)) < 0)
387 		uvcg_info(&uvc->func, "UVC connect failed with %d\n", ret);
388 }
389 
390 void
391 uvc_function_disconnect(struct uvc_device *uvc)
392 {
393 	int ret;
394 
395 	if ((ret = usb_function_deactivate(&uvc->func)) < 0)
396 		uvcg_info(&uvc->func, "UVC disconnect failed with %d\n", ret);
397 }
398 
399 /* --------------------------------------------------------------------------
400  * USB probe and disconnect
401  */
402 
403 static ssize_t function_name_show(struct device *dev,
404 				  struct device_attribute *attr, char *buf)
405 {
406 	struct uvc_device *uvc = dev_get_drvdata(dev);
407 
408 	return sprintf(buf, "%s\n", uvc->func.fi->group.cg_item.ci_name);
409 }
410 
411 static DEVICE_ATTR_RO(function_name);
412 
413 static int
414 uvc_register_video(struct uvc_device *uvc)
415 {
416 	struct usb_composite_dev *cdev = uvc->func.config->cdev;
417 	int ret;
418 
419 	/* TODO reference counting. */
420 	uvc->vdev.v4l2_dev = &uvc->v4l2_dev;
421 	uvc->vdev.fops = &uvc_v4l2_fops;
422 	uvc->vdev.ioctl_ops = &uvc_v4l2_ioctl_ops;
423 	uvc->vdev.release = video_device_release_empty;
424 	uvc->vdev.vfl_dir = VFL_DIR_TX;
425 	uvc->vdev.lock = &uvc->video.mutex;
426 	strlcpy(uvc->vdev.name, cdev->gadget->name, sizeof(uvc->vdev.name));
427 
428 	video_set_drvdata(&uvc->vdev, uvc);
429 
430 	ret = video_register_device(&uvc->vdev, VFL_TYPE_GRABBER, -1);
431 	if (ret < 0)
432 		return ret;
433 
434 	ret = device_create_file(&uvc->vdev.dev, &dev_attr_function_name);
435 	if (ret < 0) {
436 		video_unregister_device(&uvc->vdev);
437 		return ret;
438 	}
439 
440 	return 0;
441 }
442 
443 #define UVC_COPY_DESCRIPTOR(mem, dst, desc) \
444 	do { \
445 		memcpy(mem, desc, (desc)->bLength); \
446 		*(dst)++ = mem; \
447 		mem += (desc)->bLength; \
448 	} while (0);
449 
450 #define UVC_COPY_DESCRIPTORS(mem, dst, src) \
451 	do { \
452 		const struct usb_descriptor_header * const *__src; \
453 		for (__src = src; *__src; ++__src) { \
454 			memcpy(mem, *__src, (*__src)->bLength); \
455 			*dst++ = mem; \
456 			mem += (*__src)->bLength; \
457 		} \
458 	} while (0)
459 
460 static struct usb_descriptor_header **
461 uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
462 {
463 	struct uvc_input_header_descriptor *uvc_streaming_header;
464 	struct uvc_header_descriptor *uvc_control_header;
465 	const struct uvc_descriptor_header * const *uvc_control_desc;
466 	const struct uvc_descriptor_header * const *uvc_streaming_cls;
467 	const struct usb_descriptor_header * const *uvc_streaming_std;
468 	const struct usb_descriptor_header * const *src;
469 	struct usb_descriptor_header **dst;
470 	struct usb_descriptor_header **hdr;
471 	unsigned int control_size;
472 	unsigned int streaming_size;
473 	unsigned int n_desc;
474 	unsigned int bytes;
475 	void *mem;
476 
477 	switch (speed) {
478 	case USB_SPEED_SUPER:
479 		uvc_control_desc = uvc->desc.ss_control;
480 		uvc_streaming_cls = uvc->desc.ss_streaming;
481 		uvc_streaming_std = uvc_ss_streaming;
482 		break;
483 
484 	case USB_SPEED_HIGH:
485 		uvc_control_desc = uvc->desc.fs_control;
486 		uvc_streaming_cls = uvc->desc.hs_streaming;
487 		uvc_streaming_std = uvc_hs_streaming;
488 		break;
489 
490 	case USB_SPEED_FULL:
491 	default:
492 		uvc_control_desc = uvc->desc.fs_control;
493 		uvc_streaming_cls = uvc->desc.fs_streaming;
494 		uvc_streaming_std = uvc_fs_streaming;
495 		break;
496 	}
497 
498 	if (!uvc_control_desc || !uvc_streaming_cls)
499 		return ERR_PTR(-ENODEV);
500 
501 	/* Descriptors layout
502 	 *
503 	 * uvc_iad
504 	 * uvc_control_intf
505 	 * Class-specific UVC control descriptors
506 	 * uvc_control_ep
507 	 * uvc_control_cs_ep
508 	 * uvc_ss_control_comp (for SS only)
509 	 * uvc_streaming_intf_alt0
510 	 * Class-specific UVC streaming descriptors
511 	 * uvc_{fs|hs}_streaming
512 	 */
513 
514 	/* Count descriptors and compute their size. */
515 	control_size = 0;
516 	streaming_size = 0;
517 	bytes = uvc_iad.bLength + uvc_control_intf.bLength
518 	      + uvc_control_ep.bLength + uvc_control_cs_ep.bLength
519 	      + uvc_streaming_intf_alt0.bLength;
520 
521 	if (speed == USB_SPEED_SUPER) {
522 		bytes += uvc_ss_control_comp.bLength;
523 		n_desc = 6;
524 	} else {
525 		n_desc = 5;
526 	}
527 
528 	for (src = (const struct usb_descriptor_header **)uvc_control_desc;
529 	     *src; ++src) {
530 		control_size += (*src)->bLength;
531 		bytes += (*src)->bLength;
532 		n_desc++;
533 	}
534 	for (src = (const struct usb_descriptor_header **)uvc_streaming_cls;
535 	     *src; ++src) {
536 		streaming_size += (*src)->bLength;
537 		bytes += (*src)->bLength;
538 		n_desc++;
539 	}
540 	for (src = uvc_streaming_std; *src; ++src) {
541 		bytes += (*src)->bLength;
542 		n_desc++;
543 	}
544 
545 	mem = kmalloc((n_desc + 1) * sizeof(*src) + bytes, GFP_KERNEL);
546 	if (mem == NULL)
547 		return NULL;
548 
549 	hdr = mem;
550 	dst = mem;
551 	mem += (n_desc + 1) * sizeof(*src);
552 
553 	/* Copy the descriptors. */
554 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_iad);
555 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_intf);
556 
557 	uvc_control_header = mem;
558 	UVC_COPY_DESCRIPTORS(mem, dst,
559 		(const struct usb_descriptor_header **)uvc_control_desc);
560 	uvc_control_header->wTotalLength = cpu_to_le16(control_size);
561 	uvc_control_header->bInCollection = 1;
562 	uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;
563 
564 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_ep);
565 	if (speed == USB_SPEED_SUPER)
566 		UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp);
567 
568 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_cs_ep);
569 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_streaming_intf_alt0);
570 
571 	uvc_streaming_header = mem;
572 	UVC_COPY_DESCRIPTORS(mem, dst,
573 		(const struct usb_descriptor_header**)uvc_streaming_cls);
574 	uvc_streaming_header->wTotalLength = cpu_to_le16(streaming_size);
575 	uvc_streaming_header->bEndpointAddress = uvc->video.ep->address;
576 
577 	UVC_COPY_DESCRIPTORS(mem, dst, uvc_streaming_std);
578 
579 	*dst = NULL;
580 	return hdr;
581 }
582 
583 static int
584 uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
585 {
586 	struct usb_composite_dev *cdev = c->cdev;
587 	struct uvc_device *uvc = to_uvc(f);
588 	struct usb_string *us;
589 	unsigned int max_packet_mult;
590 	unsigned int max_packet_size;
591 	struct usb_ep *ep;
592 	struct f_uvc_opts *opts;
593 	int ret = -EINVAL;
594 
595 	uvcg_info(f, "%s()\n", __func__);
596 
597 	opts = fi_to_f_uvc_opts(f->fi);
598 	/* Sanity check the streaming endpoint module parameters.
599 	 */
600 	opts->streaming_interval = clamp(opts->streaming_interval, 1U, 16U);
601 	opts->streaming_maxpacket = clamp(opts->streaming_maxpacket, 1U, 3072U);
602 	opts->streaming_maxburst = min(opts->streaming_maxburst, 15U);
603 
604 	/* For SS, wMaxPacketSize has to be 1024 if bMaxBurst is not 0 */
605 	if (opts->streaming_maxburst &&
606 	    (opts->streaming_maxpacket % 1024) != 0) {
607 		opts->streaming_maxpacket = roundup(opts->streaming_maxpacket, 1024);
608 		uvcg_info(f, "overriding streaming_maxpacket to %d\n",
609 			  opts->streaming_maxpacket);
610 	}
611 
612 	/* Fill in the FS/HS/SS Video Streaming specific descriptors from the
613 	 * module parameters.
614 	 *
615 	 * NOTE: We assume that the user knows what they are doing and won't
616 	 * give parameters that their UDC doesn't support.
617 	 */
618 	if (opts->streaming_maxpacket <= 1024) {
619 		max_packet_mult = 1;
620 		max_packet_size = opts->streaming_maxpacket;
621 	} else if (opts->streaming_maxpacket <= 2048) {
622 		max_packet_mult = 2;
623 		max_packet_size = opts->streaming_maxpacket / 2;
624 	} else {
625 		max_packet_mult = 3;
626 		max_packet_size = opts->streaming_maxpacket / 3;
627 	}
628 
629 	uvc_fs_streaming_ep.wMaxPacketSize =
630 		cpu_to_le16(min(opts->streaming_maxpacket, 1023U));
631 	uvc_fs_streaming_ep.bInterval = opts->streaming_interval;
632 
633 	uvc_hs_streaming_ep.wMaxPacketSize =
634 		cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
635 	uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
636 
637 	uvc_ss_streaming_ep.wMaxPacketSize = cpu_to_le16(max_packet_size);
638 	uvc_ss_streaming_ep.bInterval = opts->streaming_interval;
639 	uvc_ss_streaming_comp.bmAttributes = max_packet_mult - 1;
640 	uvc_ss_streaming_comp.bMaxBurst = opts->streaming_maxburst;
641 	uvc_ss_streaming_comp.wBytesPerInterval =
642 		cpu_to_le16(max_packet_size * max_packet_mult *
643 			    (opts->streaming_maxburst + 1));
644 
645 	/* Allocate endpoints. */
646 	ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);
647 	if (!ep) {
648 		uvcg_info(f, "Unable to allocate control EP\n");
649 		goto error;
650 	}
651 	uvc->control_ep = ep;
652 
653 	if (gadget_is_superspeed(c->cdev->gadget))
654 		ep = usb_ep_autoconfig_ss(cdev->gadget, &uvc_ss_streaming_ep,
655 					  &uvc_ss_streaming_comp);
656 	else if (gadget_is_dualspeed(cdev->gadget))
657 		ep = usb_ep_autoconfig(cdev->gadget, &uvc_hs_streaming_ep);
658 	else
659 		ep = usb_ep_autoconfig(cdev->gadget, &uvc_fs_streaming_ep);
660 
661 	if (!ep) {
662 		uvcg_info(f, "Unable to allocate streaming EP\n");
663 		goto error;
664 	}
665 	uvc->video.ep = ep;
666 
667 	uvc_fs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
668 	uvc_hs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
669 	uvc_ss_streaming_ep.bEndpointAddress = uvc->video.ep->address;
670 
671 	us = usb_gstrings_attach(cdev, uvc_function_strings,
672 				 ARRAY_SIZE(uvc_en_us_strings));
673 	if (IS_ERR(us)) {
674 		ret = PTR_ERR(us);
675 		goto error;
676 	}
677 	uvc_iad.iFunction = us[UVC_STRING_CONTROL_IDX].id;
678 	uvc_control_intf.iInterface = us[UVC_STRING_CONTROL_IDX].id;
679 	ret = us[UVC_STRING_STREAMING_IDX].id;
680 	uvc_streaming_intf_alt0.iInterface = ret;
681 	uvc_streaming_intf_alt1.iInterface = ret;
682 
683 	/* Allocate interface IDs. */
684 	if ((ret = usb_interface_id(c, f)) < 0)
685 		goto error;
686 	uvc_iad.bFirstInterface = ret;
687 	uvc_control_intf.bInterfaceNumber = ret;
688 	uvc->control_intf = ret;
689 	opts->control_interface = ret;
690 
691 	if ((ret = usb_interface_id(c, f)) < 0)
692 		goto error;
693 	uvc_streaming_intf_alt0.bInterfaceNumber = ret;
694 	uvc_streaming_intf_alt1.bInterfaceNumber = ret;
695 	uvc->streaming_intf = ret;
696 	opts->streaming_interface = ret;
697 
698 	/* Copy descriptors */
699 	f->fs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);
700 	if (IS_ERR(f->fs_descriptors)) {
701 		ret = PTR_ERR(f->fs_descriptors);
702 		f->fs_descriptors = NULL;
703 		goto error;
704 	}
705 	if (gadget_is_dualspeed(cdev->gadget)) {
706 		f->hs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_HIGH);
707 		if (IS_ERR(f->hs_descriptors)) {
708 			ret = PTR_ERR(f->hs_descriptors);
709 			f->hs_descriptors = NULL;
710 			goto error;
711 		}
712 	}
713 	if (gadget_is_superspeed(c->cdev->gadget)) {
714 		f->ss_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_SUPER);
715 		if (IS_ERR(f->ss_descriptors)) {
716 			ret = PTR_ERR(f->ss_descriptors);
717 			f->ss_descriptors = NULL;
718 			goto error;
719 		}
720 	}
721 
722 	/* Preallocate control endpoint request. */
723 	uvc->control_req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
724 	uvc->control_buf = kmalloc(UVC_MAX_REQUEST_SIZE, GFP_KERNEL);
725 	if (uvc->control_req == NULL || uvc->control_buf == NULL) {
726 		ret = -ENOMEM;
727 		goto error;
728 	}
729 
730 	uvc->control_req->buf = uvc->control_buf;
731 	uvc->control_req->complete = uvc_function_ep0_complete;
732 	uvc->control_req->context = uvc;
733 
734 	if (v4l2_device_register(&cdev->gadget->dev, &uvc->v4l2_dev)) {
735 		uvcg_err(f, "failed to register V4L2 device\n");
736 		goto error;
737 	}
738 
739 	/* Initialise video. */
740 	ret = uvcg_video_init(&uvc->video, uvc);
741 	if (ret < 0)
742 		goto error;
743 
744 	/* Register a V4L2 device. */
745 	ret = uvc_register_video(uvc);
746 	if (ret < 0) {
747 		uvcg_err(f, "failed to register video device\n");
748 		goto error;
749 	}
750 
751 	return 0;
752 
753 error:
754 	v4l2_device_unregister(&uvc->v4l2_dev);
755 
756 	if (uvc->control_req)
757 		usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
758 	kfree(uvc->control_buf);
759 
760 	usb_free_all_descriptors(f);
761 	return ret;
762 }
763 
764 /* --------------------------------------------------------------------------
765  * USB gadget function
766  */
767 
768 static void uvc_free_inst(struct usb_function_instance *f)
769 {
770 	struct f_uvc_opts *opts = fi_to_f_uvc_opts(f);
771 
772 	mutex_destroy(&opts->lock);
773 	kfree(opts);
774 }
775 
776 static struct usb_function_instance *uvc_alloc_inst(void)
777 {
778 	struct f_uvc_opts *opts;
779 	struct uvc_camera_terminal_descriptor *cd;
780 	struct uvc_processing_unit_descriptor *pd;
781 	struct uvc_output_terminal_descriptor *od;
782 	struct uvc_color_matching_descriptor *md;
783 	struct uvc_descriptor_header **ctl_cls;
784 	int ret;
785 
786 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
787 	if (!opts)
788 		return ERR_PTR(-ENOMEM);
789 	opts->func_inst.free_func_inst = uvc_free_inst;
790 	mutex_init(&opts->lock);
791 
792 	cd = &opts->uvc_camera_terminal;
793 	cd->bLength			= UVC_DT_CAMERA_TERMINAL_SIZE(3);
794 	cd->bDescriptorType		= USB_DT_CS_INTERFACE;
795 	cd->bDescriptorSubType		= UVC_VC_INPUT_TERMINAL;
796 	cd->bTerminalID			= 1;
797 	cd->wTerminalType		= cpu_to_le16(0x0201);
798 	cd->bAssocTerminal		= 0;
799 	cd->iTerminal			= 0;
800 	cd->wObjectiveFocalLengthMin	= cpu_to_le16(0);
801 	cd->wObjectiveFocalLengthMax	= cpu_to_le16(0);
802 	cd->wOcularFocalLength		= cpu_to_le16(0);
803 	cd->bControlSize		= 3;
804 	cd->bmControls[0]		= 2;
805 	cd->bmControls[1]		= 0;
806 	cd->bmControls[2]		= 0;
807 
808 	pd = &opts->uvc_processing;
809 	pd->bLength			= UVC_DT_PROCESSING_UNIT_SIZE(2);
810 	pd->bDescriptorType		= USB_DT_CS_INTERFACE;
811 	pd->bDescriptorSubType		= UVC_VC_PROCESSING_UNIT;
812 	pd->bUnitID			= 2;
813 	pd->bSourceID			= 1;
814 	pd->wMaxMultiplier		= cpu_to_le16(16*1024);
815 	pd->bControlSize		= 2;
816 	pd->bmControls[0]		= 1;
817 	pd->bmControls[1]		= 0;
818 	pd->iProcessing			= 0;
819 
820 	od = &opts->uvc_output_terminal;
821 	od->bLength			= UVC_DT_OUTPUT_TERMINAL_SIZE;
822 	od->bDescriptorType		= USB_DT_CS_INTERFACE;
823 	od->bDescriptorSubType		= UVC_VC_OUTPUT_TERMINAL;
824 	od->bTerminalID			= 3;
825 	od->wTerminalType		= cpu_to_le16(0x0101);
826 	od->bAssocTerminal		= 0;
827 	od->bSourceID			= 2;
828 	od->iTerminal			= 0;
829 
830 	md = &opts->uvc_color_matching;
831 	md->bLength			= UVC_DT_COLOR_MATCHING_SIZE;
832 	md->bDescriptorType		= USB_DT_CS_INTERFACE;
833 	md->bDescriptorSubType		= UVC_VS_COLORFORMAT;
834 	md->bColorPrimaries		= 1;
835 	md->bTransferCharacteristics	= 1;
836 	md->bMatrixCoefficients		= 4;
837 
838 	/* Prepare fs control class descriptors for configfs-based gadgets */
839 	ctl_cls = opts->uvc_fs_control_cls;
840 	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
841 	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
842 	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
843 	ctl_cls[3] = (struct uvc_descriptor_header *)od;
844 	ctl_cls[4] = NULL;	/* NULL-terminate */
845 	opts->fs_control =
846 		(const struct uvc_descriptor_header * const *)ctl_cls;
847 
848 	/* Prepare hs control class descriptors for configfs-based gadgets */
849 	ctl_cls = opts->uvc_ss_control_cls;
850 	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
851 	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
852 	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
853 	ctl_cls[3] = (struct uvc_descriptor_header *)od;
854 	ctl_cls[4] = NULL;	/* NULL-terminate */
855 	opts->ss_control =
856 		(const struct uvc_descriptor_header * const *)ctl_cls;
857 
858 	opts->streaming_interval = 1;
859 	opts->streaming_maxpacket = 1024;
860 
861 	ret = uvcg_attach_configfs(opts);
862 	if (ret < 0) {
863 		kfree(opts);
864 		return ERR_PTR(ret);
865 	}
866 
867 	return &opts->func_inst;
868 }
869 
870 static void uvc_free(struct usb_function *f)
871 {
872 	struct uvc_device *uvc = to_uvc(f);
873 	struct f_uvc_opts *opts = container_of(f->fi, struct f_uvc_opts,
874 					       func_inst);
875 	--opts->refcnt;
876 	kfree(uvc);
877 }
878 
879 static void uvc_unbind(struct usb_configuration *c, struct usb_function *f)
880 {
881 	struct usb_composite_dev *cdev = c->cdev;
882 	struct uvc_device *uvc = to_uvc(f);
883 
884 	uvcg_info(f, "%s\n", __func__);
885 
886 	device_remove_file(&uvc->vdev.dev, &dev_attr_function_name);
887 	video_unregister_device(&uvc->vdev);
888 	v4l2_device_unregister(&uvc->v4l2_dev);
889 
890 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
891 	kfree(uvc->control_buf);
892 
893 	usb_free_all_descriptors(f);
894 }
895 
896 static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
897 {
898 	struct uvc_device *uvc;
899 	struct f_uvc_opts *opts;
900 	struct uvc_descriptor_header **strm_cls;
901 
902 	uvc = kzalloc(sizeof(*uvc), GFP_KERNEL);
903 	if (uvc == NULL)
904 		return ERR_PTR(-ENOMEM);
905 
906 	mutex_init(&uvc->video.mutex);
907 	uvc->state = UVC_STATE_DISCONNECTED;
908 	opts = fi_to_f_uvc_opts(fi);
909 
910 	mutex_lock(&opts->lock);
911 	if (opts->uvc_fs_streaming_cls) {
912 		strm_cls = opts->uvc_fs_streaming_cls;
913 		opts->fs_streaming =
914 			(const struct uvc_descriptor_header * const *)strm_cls;
915 	}
916 	if (opts->uvc_hs_streaming_cls) {
917 		strm_cls = opts->uvc_hs_streaming_cls;
918 		opts->hs_streaming =
919 			(const struct uvc_descriptor_header * const *)strm_cls;
920 	}
921 	if (opts->uvc_ss_streaming_cls) {
922 		strm_cls = opts->uvc_ss_streaming_cls;
923 		opts->ss_streaming =
924 			(const struct uvc_descriptor_header * const *)strm_cls;
925 	}
926 
927 	uvc->desc.fs_control = opts->fs_control;
928 	uvc->desc.ss_control = opts->ss_control;
929 	uvc->desc.fs_streaming = opts->fs_streaming;
930 	uvc->desc.hs_streaming = opts->hs_streaming;
931 	uvc->desc.ss_streaming = opts->ss_streaming;
932 	++opts->refcnt;
933 	mutex_unlock(&opts->lock);
934 
935 	/* Register the function. */
936 	uvc->func.name = "uvc";
937 	uvc->func.bind = uvc_function_bind;
938 	uvc->func.unbind = uvc_unbind;
939 	uvc->func.get_alt = uvc_function_get_alt;
940 	uvc->func.set_alt = uvc_function_set_alt;
941 	uvc->func.disable = uvc_function_disable;
942 	uvc->func.setup = uvc_function_setup;
943 	uvc->func.free_func = uvc_free;
944 	uvc->func.bind_deactivated = true;
945 
946 	return &uvc->func;
947 }
948 
949 DECLARE_USB_FUNCTION_INIT(uvc, uvc_alloc_inst, uvc_alloc);
950 MODULE_LICENSE("GPL");
951 MODULE_AUTHOR("Laurent Pinchart");
952