1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *	uvc_video.c  --  USB Video Class Gadget driver
4  *
5  *	Copyright (C) 2009-2010
6  *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/device.h>
11 #include <linux/errno.h>
12 #include <linux/usb/ch9.h>
13 #include <linux/usb/gadget.h>
14 #include <linux/usb/video.h>
15 
16 #include <media/v4l2-dev.h>
17 
18 #include "uvc.h"
19 #include "uvc_queue.h"
20 #include "uvc_video.h"
21 
22 /* --------------------------------------------------------------------------
23  * Video codecs
24  */
25 
26 static int
27 uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
28 		u8 *data, int len)
29 {
30 	data[0] = 2;
31 	data[1] = UVC_STREAM_EOH | video->fid;
32 
33 	if (buf->bytesused - video->queue.buf_used <= len - 2)
34 		data[1] |= UVC_STREAM_EOF;
35 
36 	return 2;
37 }
38 
39 static int
40 uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
41 		u8 *data, int len)
42 {
43 	struct uvc_video_queue *queue = &video->queue;
44 	unsigned int nbytes;
45 	void *mem;
46 
47 	/* Copy video data to the USB buffer. */
48 	mem = buf->mem + queue->buf_used;
49 	nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
50 
51 	memcpy(data, mem, nbytes);
52 	queue->buf_used += nbytes;
53 
54 	return nbytes;
55 }
56 
57 static void
58 uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
59 		struct uvc_buffer *buf)
60 {
61 	void *mem = req->buf;
62 	int len = video->req_size;
63 	int ret;
64 
65 	/* Add a header at the beginning of the payload. */
66 	if (video->payload_size == 0) {
67 		ret = uvc_video_encode_header(video, buf, mem, len);
68 		video->payload_size += ret;
69 		mem += ret;
70 		len -= ret;
71 	}
72 
73 	/* Process video data. */
74 	len = min((int)(video->max_payload_size - video->payload_size), len);
75 	ret = uvc_video_encode_data(video, buf, mem, len);
76 
77 	video->payload_size += ret;
78 	len -= ret;
79 
80 	req->length = video->req_size - len;
81 	req->zero = video->payload_size == video->max_payload_size;
82 
83 	if (buf->bytesused == video->queue.buf_used) {
84 		video->queue.buf_used = 0;
85 		buf->state = UVC_BUF_STATE_DONE;
86 		uvcg_queue_next_buffer(&video->queue, buf);
87 		video->fid ^= UVC_STREAM_FID;
88 
89 		video->payload_size = 0;
90 	}
91 
92 	if (video->payload_size == video->max_payload_size ||
93 	    buf->bytesused == video->queue.buf_used)
94 		video->payload_size = 0;
95 }
96 
97 static void
98 uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
99 		struct uvc_buffer *buf)
100 {
101 	void *mem = req->buf;
102 	int len = video->req_size;
103 	int ret;
104 
105 	/* Add the header. */
106 	ret = uvc_video_encode_header(video, buf, mem, len);
107 	mem += ret;
108 	len -= ret;
109 
110 	/* Process video data. */
111 	ret = uvc_video_encode_data(video, buf, mem, len);
112 	len -= ret;
113 
114 	req->length = video->req_size - len;
115 
116 	if (buf->bytesused == video->queue.buf_used) {
117 		video->queue.buf_used = 0;
118 		buf->state = UVC_BUF_STATE_DONE;
119 		uvcg_queue_next_buffer(&video->queue, buf);
120 		video->fid ^= UVC_STREAM_FID;
121 	}
122 }
123 
124 /* --------------------------------------------------------------------------
125  * Request handling
126  */
127 
128 static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
129 {
130 	int ret;
131 
132 	ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
133 	if (ret < 0) {
134 		uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
135 			 ret);
136 
137 		/* Isochronous endpoints can't be halted. */
138 		if (usb_endpoint_xfer_bulk(video->ep->desc))
139 			usb_ep_set_halt(video->ep);
140 	}
141 
142 	return ret;
143 }
144 
145 static void
146 uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
147 {
148 	struct uvc_video *video = req->context;
149 	struct uvc_video_queue *queue = &video->queue;
150 	unsigned long flags;
151 
152 	switch (req->status) {
153 	case 0:
154 		break;
155 
156 	case -ESHUTDOWN:	/* disconnect from host. */
157 		uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
158 		uvcg_queue_cancel(queue, 1);
159 		break;
160 
161 	default:
162 		uvcg_info(&video->uvc->func,
163 			  "VS request completed with status %d.\n",
164 			  req->status);
165 		uvcg_queue_cancel(queue, 0);
166 	}
167 
168 	spin_lock_irqsave(&video->req_lock, flags);
169 	list_add_tail(&req->list, &video->req_free);
170 	spin_unlock_irqrestore(&video->req_lock, flags);
171 
172 	schedule_work(&video->pump);
173 }
174 
175 static int
176 uvc_video_free_requests(struct uvc_video *video)
177 {
178 	unsigned int i;
179 
180 	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
181 		if (video->req[i]) {
182 			usb_ep_free_request(video->ep, video->req[i]);
183 			video->req[i] = NULL;
184 		}
185 
186 		if (video->req_buffer[i]) {
187 			kfree(video->req_buffer[i]);
188 			video->req_buffer[i] = NULL;
189 		}
190 	}
191 
192 	INIT_LIST_HEAD(&video->req_free);
193 	video->req_size = 0;
194 	return 0;
195 }
196 
197 static int
198 uvc_video_alloc_requests(struct uvc_video *video)
199 {
200 	unsigned int req_size;
201 	unsigned int i;
202 	int ret = -ENOMEM;
203 
204 	BUG_ON(video->req_size);
205 
206 	req_size = video->ep->maxpacket
207 		 * max_t(unsigned int, video->ep->maxburst, 1)
208 		 * (video->ep->mult);
209 
210 	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
211 		video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);
212 		if (video->req_buffer[i] == NULL)
213 			goto error;
214 
215 		video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
216 		if (video->req[i] == NULL)
217 			goto error;
218 
219 		video->req[i]->buf = video->req_buffer[i];
220 		video->req[i]->length = 0;
221 		video->req[i]->complete = uvc_video_complete;
222 		video->req[i]->context = video;
223 
224 		list_add_tail(&video->req[i]->list, &video->req_free);
225 	}
226 
227 	video->req_size = req_size;
228 
229 	return 0;
230 
231 error:
232 	uvc_video_free_requests(video);
233 	return ret;
234 }
235 
236 /* --------------------------------------------------------------------------
237  * Video streaming
238  */
239 
240 /*
241  * uvcg_video_pump - Pump video data into the USB requests
242  *
243  * This function fills the available USB requests (listed in req_free) with
244  * video data from the queued buffers.
245  */
246 static void uvcg_video_pump(struct work_struct *work)
247 {
248 	struct uvc_video *video = container_of(work, struct uvc_video, pump);
249 	struct uvc_video_queue *queue = &video->queue;
250 	struct usb_request *req;
251 	struct uvc_buffer *buf;
252 	unsigned long flags;
253 	int ret;
254 
255 	while (1) {
256 		/* Retrieve the first available USB request, protected by the
257 		 * request lock.
258 		 */
259 		spin_lock_irqsave(&video->req_lock, flags);
260 		if (list_empty(&video->req_free)) {
261 			spin_unlock_irqrestore(&video->req_lock, flags);
262 			return;
263 		}
264 		req = list_first_entry(&video->req_free, struct usb_request,
265 					list);
266 		list_del(&req->list);
267 		spin_unlock_irqrestore(&video->req_lock, flags);
268 
269 		/* Retrieve the first available video buffer and fill the
270 		 * request, protected by the video queue irqlock.
271 		 */
272 		spin_lock_irqsave(&queue->irqlock, flags);
273 		buf = uvcg_queue_head(queue);
274 		if (buf == NULL) {
275 			spin_unlock_irqrestore(&queue->irqlock, flags);
276 			break;
277 		}
278 
279 		video->encode(req, video, buf);
280 
281 		/* Queue the USB request */
282 		ret = uvcg_video_ep_queue(video, req);
283 		spin_unlock_irqrestore(&queue->irqlock, flags);
284 
285 		if (ret < 0) {
286 			uvcg_queue_cancel(queue, 0);
287 			break;
288 		}
289 	}
290 
291 	spin_lock_irqsave(&video->req_lock, flags);
292 	list_add_tail(&req->list, &video->req_free);
293 	spin_unlock_irqrestore(&video->req_lock, flags);
294 	return;
295 }
296 
297 /*
298  * Enable or disable the video stream.
299  */
300 int uvcg_video_enable(struct uvc_video *video, int enable)
301 {
302 	unsigned int i;
303 	int ret;
304 
305 	if (video->ep == NULL) {
306 		uvcg_info(&video->uvc->func,
307 			  "Video enable failed, device is uninitialized.\n");
308 		return -ENODEV;
309 	}
310 
311 	if (!enable) {
312 		cancel_work_sync(&video->pump);
313 		uvcg_queue_cancel(&video->queue, 0);
314 
315 		for (i = 0; i < UVC_NUM_REQUESTS; ++i)
316 			if (video->req[i])
317 				usb_ep_dequeue(video->ep, video->req[i]);
318 
319 		uvc_video_free_requests(video);
320 		uvcg_queue_enable(&video->queue, 0);
321 		return 0;
322 	}
323 
324 	if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
325 		return ret;
326 
327 	if ((ret = uvc_video_alloc_requests(video)) < 0)
328 		return ret;
329 
330 	if (video->max_payload_size) {
331 		video->encode = uvc_video_encode_bulk;
332 		video->payload_size = 0;
333 	} else
334 		video->encode = uvc_video_encode_isoc;
335 
336 	schedule_work(&video->pump);
337 
338 	return ret;
339 }
340 
341 /*
342  * Initialize the UVC video stream.
343  */
344 int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
345 {
346 	INIT_LIST_HEAD(&video->req_free);
347 	spin_lock_init(&video->req_lock);
348 	INIT_WORK(&video->pump, uvcg_video_pump);
349 
350 	video->uvc = uvc;
351 	video->fcc = V4L2_PIX_FMT_YUYV;
352 	video->bpp = 16;
353 	video->width = 320;
354 	video->height = 240;
355 	video->imagesize = 320 * 240 * 2;
356 
357 	/* Initialize the video buffers queue. */
358 	uvcg_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT,
359 			&video->mutex);
360 	return 0;
361 }
362 
363