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
uvc_video_encode_header(struct uvc_video * video,struct uvc_buffer * buf,u8 * data,int len)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
uvc_video_encode_data(struct uvc_video * video,struct uvc_buffer * buf,u8 * data,int len)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
uvc_video_encode_bulk(struct usb_request * req,struct uvc_video * video,struct uvc_buffer * buf)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
uvc_video_encode_isoc(struct usb_request * req,struct uvc_video * video,struct uvc_buffer * buf)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
uvcg_video_ep_queue(struct uvc_video * video,struct usb_request * req)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
uvc_video_complete(struct usb_ep * ep,struct usb_request * req)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
uvc_video_free_requests(struct uvc_video * video)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
uvc_video_alloc_requests(struct uvc_video * video)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 */
uvcg_video_pump(struct work_struct * work)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 */
uvcg_video_enable(struct uvc_video * video,int enable)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 */
uvcg_video_init(struct uvc_video * video,struct uvc_device * uvc)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