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1/*
2 * uvc_video.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/usb/ch9.h>
17#include <linux/usb/gadget.h>
18#include <linux/usb/video.h>
19
20#include <media/v4l2-dev.h>
21
22#include "uvc.h"
23#include "uvc_queue.h"
24#include "uvc_video.h"
25
26/* --------------------------------------------------------------------------
27 * Video codecs
28 */
29
30static int
31uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
32 u8 *data, int len)
33{
34 data[0] = 2;
35 data[1] = UVC_STREAM_EOH | video->fid;
36
37 if (buf->bytesused - video->queue.buf_used <= len - 2)
38 data[1] |= UVC_STREAM_EOF;
39
40 return 2;
41}
42
43static int
44uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
45 u8 *data, int len)
46{
47 struct uvc_video_queue *queue = &video->queue;
48 unsigned int nbytes;
49 void *mem;
50
51 /* Copy video data to the USB buffer. */
52 mem = buf->mem + queue->buf_used;
53 nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
54
55 memcpy(data, mem, nbytes);
56 queue->buf_used += nbytes;
57
58 return nbytes;
59}
60
61static void
62uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
63 struct uvc_buffer *buf)
64{
65 void *mem = req->buf;
66 int len = video->req_size;
67 int ret;
68
69 /* Add a header at the beginning of the payload. */
70 if (video->payload_size == 0) {
71 ret = uvc_video_encode_header(video, buf, mem, len);
72 video->payload_size += ret;
73 mem += ret;
74 len -= ret;
75 }
76
77 /* Process video data. */
78 len = min((int)(video->max_payload_size - video->payload_size), len);
79 ret = uvc_video_encode_data(video, buf, mem, len);
80
81 video->payload_size += ret;
82 len -= ret;
83
84 req->length = video->req_size - len;
85 req->zero = video->payload_size == video->max_payload_size;
86
87 if (buf->bytesused == video->queue.buf_used) {
88 video->queue.buf_used = 0;
89 buf->state = UVC_BUF_STATE_DONE;
90 uvcg_queue_next_buffer(&video->queue, buf);
91 video->fid ^= UVC_STREAM_FID;
92
93 video->payload_size = 0;
94 }
95
96 if (video->payload_size == video->max_payload_size ||
97 buf->bytesused == video->queue.buf_used)
98 video->payload_size = 0;
99}
100
101static void
102uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
103 struct uvc_buffer *buf)
104{
105 void *mem = req->buf;
106 int len = video->req_size;
107 int ret;
108
109 /* Add the header. */
110 ret = uvc_video_encode_header(video, buf, mem, len);
111 mem += ret;
112 len -= ret;
113
114 /* Process video data. */
115 ret = uvc_video_encode_data(video, buf, mem, len);
116 len -= ret;
117
118 req->length = video->req_size - len;
119
120 if (buf->bytesused == video->queue.buf_used) {
121 video->queue.buf_used = 0;
122 buf->state = UVC_BUF_STATE_DONE;
123 uvcg_queue_next_buffer(&video->queue, buf);
124 video->fid ^= UVC_STREAM_FID;
125 }
126}
127
128/* --------------------------------------------------------------------------
129 * Request handling
130 */
131
132/*
133 * I somehow feel that synchronisation won't be easy to achieve here. We have
134 * three events that control USB requests submission:
135 *
136 * - USB request completion: the completion handler will resubmit the request
137 * if a video buffer is available.
138 *
139 * - USB interface setting selection: in response to a SET_INTERFACE request,
140 * the handler will start streaming if a video buffer is available and if
141 * video is not currently streaming.
142 *
143 * - V4L2 buffer queueing: the driver will start streaming if video is not
144 * currently streaming.
145 *
146 * Race conditions between those 3 events might lead to deadlocks or other
147 * nasty side effects.
148 *
149 * The "video currently streaming" condition can't be detected by the irqqueue
150 * being empty, as a request can still be in flight. A separate "queue paused"
151 * flag is thus needed.
152 *
153 * The paused flag will be set when we try to retrieve the irqqueue head if the
154 * queue is empty, and cleared when we queue a buffer.
155 *
156 * The USB request completion handler will get the buffer at the irqqueue head
157 * under protection of the queue spinlock. If the queue is empty, the streaming
158 * paused flag will be set. Right after releasing the spinlock a userspace
159 * application can queue a buffer. The flag will then cleared, and the ioctl
160 * handler will restart the video stream.
161 */
162static void
163uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
164{
165 struct uvc_video *video = req->context;
166 struct uvc_video_queue *queue = &video->queue;
167 struct uvc_buffer *buf;
168 unsigned long flags;
169 int ret;
170
171 switch (req->status) {
172 case 0:
173 break;
174
175 case -ESHUTDOWN: /* disconnect from host. */
176 printk(KERN_DEBUG "VS request cancelled.\n");
177 uvcg_queue_cancel(queue, 1);
178 goto requeue;
179
180 default:
181 printk(KERN_INFO "VS request completed with status %d.\n",
182 req->status);
183 uvcg_queue_cancel(queue, 0);
184 goto requeue;
185 }
186
187 spin_lock_irqsave(&video->queue.irqlock, flags);
188 buf = uvcg_queue_head(&video->queue);
189 if (buf == NULL) {
190 spin_unlock_irqrestore(&video->queue.irqlock, flags);
191 goto requeue;
192 }
193
194 video->encode(req, video, buf);
195
196 if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) {
197 printk(KERN_INFO "Failed to queue request (%d).\n", ret);
198 usb_ep_set_halt(ep);
199 spin_unlock_irqrestore(&video->queue.irqlock, flags);
200 uvcg_queue_cancel(queue, 0);
201 goto requeue;
202 }
203 spin_unlock_irqrestore(&video->queue.irqlock, flags);
204
205 return;
206
207requeue:
208 spin_lock_irqsave(&video->req_lock, flags);
209 list_add_tail(&req->list, &video->req_free);
210 spin_unlock_irqrestore(&video->req_lock, flags);
211}
212
213static int
214uvc_video_free_requests(struct uvc_video *video)
215{
216 unsigned int i;
217
218 for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
219 if (video->req[i]) {
220 usb_ep_free_request(video->ep, video->req[i]);
221 video->req[i] = NULL;
222 }
223
224 if (video->req_buffer[i]) {
225 kfree(video->req_buffer[i]);
226 video->req_buffer[i] = NULL;
227 }
228 }
229
230 INIT_LIST_HEAD(&video->req_free);
231 video->req_size = 0;
232 return 0;
233}
234
235static int
236uvc_video_alloc_requests(struct uvc_video *video)
237{
238 unsigned int req_size;
239 unsigned int i;
240 int ret = -ENOMEM;
241
242 BUG_ON(video->req_size);
243
244 req_size = video->ep->maxpacket
245 * max_t(unsigned int, video->ep->maxburst, 1)
246 * (video->ep->mult + 1);
247
248 for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
249 video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);
250 if (video->req_buffer[i] == NULL)
251 goto error;
252
253 video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
254 if (video->req[i] == NULL)
255 goto error;
256
257 video->req[i]->buf = video->req_buffer[i];
258 video->req[i]->length = 0;
259 video->req[i]->complete = uvc_video_complete;
260 video->req[i]->context = video;
261
262 list_add_tail(&video->req[i]->list, &video->req_free);
263 }
264
265 video->req_size = req_size;
266
267 return 0;
268
269error:
270 uvc_video_free_requests(video);
271 return ret;
272}
273
274/* --------------------------------------------------------------------------
275 * Video streaming
276 */
277
278/*
279 * uvcg_video_pump - Pump video data into the USB requests
280 *
281 * This function fills the available USB requests (listed in req_free) with
282 * video data from the queued buffers.
283 */
284int uvcg_video_pump(struct uvc_video *video)
285{
286 struct uvc_video_queue *queue = &video->queue;
287 struct usb_request *req;
288 struct uvc_buffer *buf;
289 unsigned long flags;
290 int ret;
291
292 /* FIXME TODO Race between uvcg_video_pump and requests completion
293 * handler ???
294 */
295
296 while (1) {
297 /* Retrieve the first available USB request, protected by the
298 * request lock.
299 */
300 spin_lock_irqsave(&video->req_lock, flags);
301 if (list_empty(&video->req_free)) {
302 spin_unlock_irqrestore(&video->req_lock, flags);
303 return 0;
304 }
305 req = list_first_entry(&video->req_free, struct usb_request,
306 list);
307 list_del(&req->list);
308 spin_unlock_irqrestore(&video->req_lock, flags);
309
310 /* Retrieve the first available video buffer and fill the
311 * request, protected by the video queue irqlock.
312 */
313 spin_lock_irqsave(&queue->irqlock, flags);
314 buf = uvcg_queue_head(queue);
315 if (buf == NULL) {
316 spin_unlock_irqrestore(&queue->irqlock, flags);
317 break;
318 }
319
320 video->encode(req, video, buf);
321
322 /* Queue the USB request */
323 ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
324 if (ret < 0) {
325 printk(KERN_INFO "Failed to queue request (%d)\n", ret);
326 usb_ep_set_halt(video->ep);
327 spin_unlock_irqrestore(&queue->irqlock, flags);
328 uvcg_queue_cancel(queue, 0);
329 break;
330 }
331 spin_unlock_irqrestore(&queue->irqlock, flags);
332 }
333
334 spin_lock_irqsave(&video->req_lock, flags);
335 list_add_tail(&req->list, &video->req_free);
336 spin_unlock_irqrestore(&video->req_lock, flags);
337 return 0;
338}
339
340/*
341 * Enable or disable the video stream.
342 */
343int uvcg_video_enable(struct uvc_video *video, int enable)
344{
345 unsigned int i;
346 int ret;
347
348 if (video->ep == NULL) {
349 printk(KERN_INFO "Video enable failed, device is "
350 "uninitialized.\n");
351 return -ENODEV;
352 }
353
354 if (!enable) {
355 for (i = 0; i < UVC_NUM_REQUESTS; ++i)
356 if (video->req[i])
357 usb_ep_dequeue(video->ep, video->req[i]);
358
359 uvc_video_free_requests(video);
360 uvcg_queue_enable(&video->queue, 0);
361 return 0;
362 }
363
364 if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
365 return ret;
366
367 if ((ret = uvc_video_alloc_requests(video)) < 0)
368 return ret;
369
370 if (video->max_payload_size) {
371 video->encode = uvc_video_encode_bulk;
372 video->payload_size = 0;
373 } else
374 video->encode = uvc_video_encode_isoc;
375
376 return uvcg_video_pump(video);
377}
378
379/*
380 * Initialize the UVC video stream.
381 */
382int uvcg_video_init(struct uvc_video *video)
383{
384 INIT_LIST_HEAD(&video->req_free);
385 spin_lock_init(&video->req_lock);
386
387 video->fcc = V4L2_PIX_FMT_YUYV;
388 video->bpp = 16;
389 video->width = 320;
390 video->height = 240;
391 video->imagesize = 320 * 240 * 2;
392
393 /* Initialize the video buffers queue. */
394 uvcg_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT,
395 &video->mutex);
396 return 0;
397}
398
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
26static int
27uvc_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
39static int
40uvc_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
57static void
58uvc_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
97static void
98uvc_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
128static 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
145static void
146uvc_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
175static int
176uvc_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
197static int
198uvc_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
231error:
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 */
246static 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 */
300int 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 */
344int 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