aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/usb/gadget/uvc_queue.c
blob: 1c29bc954db9f02f1954073861629e2b9be74c4d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
/*
 *	uvc_queue.c  --  USB Video Class driver - Buffers management
 *
 *	Copyright (C) 2005-2010
 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 */

#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>

#include <media/v4l2-common.h>
#include <media/videobuf2-vmalloc.h>

#include "uvc.h"

/* ------------------------------------------------------------------------
 * Video buffers queue management.
 *
 * Video queues is initialized by uvc_queue_init(). The function performs
 * basic initialization of the uvc_video_queue struct and never fails.
 *
 * Video buffers are managed by videobuf2. The driver uses a mutex to protect
 * the videobuf2 queue operations by serializing calls to videobuf2 and a
 * spinlock to protect the IRQ queue that holds the buffers to be processed by
 * the driver.
 */

/* -----------------------------------------------------------------------------
 * videobuf2 queue operations
 */

static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
			   unsigned int *nbuffers, unsigned int *nplanes,
			   unsigned int sizes[], void *alloc_ctxs[])
{
	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
	struct uvc_video *video = container_of(queue, struct uvc_video, queue);

	if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
		*nbuffers = UVC_MAX_VIDEO_BUFFERS;

	*nplanes = 1;

	sizes[0] = video->imagesize;

	return 0;
}

static int uvc_buffer_prepare(struct vb2_buffer *vb)
{
	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
	struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);

	if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
	    vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
		return -EINVAL;
	}

	if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
		return -ENODEV;

	buf->state = UVC_BUF_STATE_QUEUED;
	buf->mem = vb2_plane_vaddr(vb, 0);
	buf->length = vb2_plane_size(vb, 0);
	if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
		buf->bytesused = 0;
	else
		buf->bytesused = vb2_get_plane_payload(vb, 0);

	return 0;
}

static void uvc_buffer_queue(struct vb2_buffer *vb)
{
	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
	struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
	unsigned long flags;

	spin_lock_irqsave(&queue->irqlock, flags);

	if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
		list_add_tail(&buf->queue, &queue->irqqueue);
	} else {
		/* If the device is disconnected return the buffer to userspace
		 * directly. The next QBUF call will fail with -ENODEV.
		 */
		buf->state = UVC_BUF_STATE_ERROR;
		vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
	}

	spin_unlock_irqrestore(&queue->irqlock, flags);
}

static void uvc_wait_prepare(struct vb2_queue *vq)
{
	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);

	mutex_unlock(&queue->mutex);
}

static void uvc_wait_finish(struct vb2_queue *vq)
{
	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);

	mutex_lock(&queue->mutex);
}

static struct vb2_ops uvc_queue_qops = {
	.queue_setup = uvc_queue_setup,
	.buf_prepare = uvc_buffer_prepare,
	.buf_queue = uvc_buffer_queue,
	.wait_prepare = uvc_wait_prepare,
	.wait_finish = uvc_wait_finish,
};

static int uvc_queue_init(struct uvc_video_queue *queue,
			  enum v4l2_buf_type type)
{
	int ret;

	queue->queue.type = type;
	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
	queue->queue.drv_priv = queue;
	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
	queue->queue.ops = &uvc_queue_qops;
	queue->queue.mem_ops = &vb2_vmalloc_memops;
	queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
				     | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
	ret = vb2_queue_init(&queue->queue);
	if (ret)
		return ret;

	mutex_init(&queue->mutex);
	spin_lock_init(&queue->irqlock);
	INIT_LIST_HEAD(&queue->irqqueue);
	queue->flags = 0;

	return 0;
}

/*
 * Free the video buffers.
 */
static void uvc_free_buffers(struct uvc_video_queue *queue)
{
	mutex_lock(&queue->mutex);
	vb2_queue_release(&queue->queue);
	mutex_unlock(&queue->mutex);
}

/*
 * Allocate the video buffers.
 */
static int uvc_alloc_buffers(struct uvc_video_queue *queue,
			     struct v4l2_requestbuffers *rb)
{
	int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_reqbufs(&queue->queue, rb);
	mutex_unlock(&queue->mutex);

	return ret ? ret : rb->count;
}

static int uvc_query_buffer(struct uvc_video_queue *queue,
			    struct v4l2_buffer *buf)
{
	int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_querybuf(&queue->queue, buf);
	mutex_unlock(&queue->mutex);

	return ret;
}

static int uvc_queue_buffer(struct uvc_video_queue *queue,
			    struct v4l2_buffer *buf)
{
	unsigned long flags;
	int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_qbuf(&queue->queue, buf);
	if (ret < 0)
		goto done;

	spin_lock_irqsave(&queue->irqlock, flags);
	ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
	queue->flags &= ~UVC_QUEUE_PAUSED;
	spin_unlock_irqrestore(&queue->irqlock, flags);

done:
	mutex_unlock(&queue->mutex);
	return ret;
}

/*
 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
 * available.
 */
static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
			      struct v4l2_buffer *buf, int nonblocking)
{
	int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
	mutex_unlock(&queue->mutex);

	return ret;
}

/*
 * Poll the video queue.
 *
 * This function implements video queue polling and is intended to be used by
 * the device poll handler.
 */
static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
				   struct file *file, poll_table *wait)
{
	unsigned int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_poll(&queue->queue, file, wait);
	mutex_unlock(&queue->mutex);

	return ret;
}

static int uvc_queue_mmap(struct uvc_video_queue *queue,
			  struct vm_area_struct *vma)
{
	int ret;

	mutex_lock(&queue->mutex);
	ret = vb2_mmap(&queue->queue, vma);
	mutex_unlock(&queue->mutex);

	return ret;
}

#ifndef CONFIG_MMU
/*
 * Get unmapped area.
 *
 * NO-MMU arch need this function to make mmap() work correctly.
 */
static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
		unsigned long pgoff)
{
	unsigned long ret;

	mutex_lock(&queue->mutex);
	ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
	mutex_unlock(&queue->mutex);
	return ret;
}
#endif

/*
 * Cancel the video buffers queue.
 *
 * Cancelling the queue marks all buffers on the irq queue as erroneous,
 * wakes them up and removes them from the queue.
 *
 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 * fail with -ENODEV.
 *
 * This function acquires the irq spinlock and can be called from interrupt
 * context.
 */
static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
{
	struct uvc_buffer *buf;
	unsigned long flags;

	spin_lock_irqsave(&queue->irqlock, flags);
	while (!list_empty(&queue->irqqueue)) {
		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
				       queue);
		list_del(&buf->queue);
		buf->state = UVC_BUF_STATE_ERROR;
		vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
	}
	/* This must be protected by the irqlock spinlock to avoid race
	 * conditions between uvc_queue_buffer and the disconnection event that
	 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
	 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
	 * state outside the queue code.
	 */
	if (disconnect)
		queue->flags |= UVC_QUEUE_DISCONNECTED;
	spin_unlock_irqrestore(&queue->irqlock, flags);
}

/*
 * Enable or disable the video buffers queue.
 *
 * The queue must be enabled before starting video acquisition and must be
 * disabled after stopping it. This ensures that the video buffers queue
 * state can be properly initialized before buffers are accessed from the
 * interrupt handler.
 *
 * Enabling the video queue initializes parameters (such as sequence number,
 * sync pattern, ...). If the queue is already enabled, return -EBUSY.
 *
 * Disabling the video queue cancels the queue and removes all buffers from
 * the main queue.
 *
 * This function can't be called from interrupt context. Use
 * uvc_queue_cancel() instead.
 */
static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
{
	unsigned long flags;
	int ret = 0;

	mutex_lock(&queue->mutex);
	if (enable) {
		ret = vb2_streamon(&queue->queue, queue->queue.type);
		if (ret < 0)
			goto done;

		queue->sequence = 0;
		queue->buf_used = 0;
	} else {
		ret = vb2_streamoff(&queue->queue, queue->queue.type);
		if (ret < 0)
			goto done;

		spin_lock_irqsave(&queue->irqlock, flags);
		INIT_LIST_HEAD(&queue->irqqueue);

		/*
		 * FIXME: We need to clear the DISCONNECTED flag to ensure that
		 * applications will be able to queue buffers for the next
		 * streaming run. However, clearing it here doesn't guarantee
		 * that the device will be reconnected in the meantime.
		 */
		queue->flags &= ~UVC_QUEUE_DISCONNECTED;
		spin_unlock_irqrestore(&queue->irqlock, flags);
	}

done:
	mutex_unlock(&queue->mutex);
	return ret;
}

/* called with &queue_irqlock held.. */
static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
						struct uvc_buffer *buf)
{
	struct uvc_buffer *nextbuf;

	if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
	     buf->length != buf->bytesused) {
		buf->state = UVC_BUF_STATE_QUEUED;
		vb2_set_plane_payload(&buf->buf, 0, 0);
		return buf;
	}

	list_del(&buf->queue);
	if (!list_empty(&queue->irqqueue))
		nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
					   queue);
	else
		nextbuf = NULL;

	buf->buf.v4l2_buf.field = V4L2_FIELD_NONE;
	buf->buf.v4l2_buf.sequence = queue->sequence++;
	v4l2_get_timestamp(&buf->buf.v4l2_buf.timestamp);

	vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
	vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);

	return nextbuf;
}

static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
{
	struct uvc_buffer *buf = NULL;

	if (!list_empty(&queue->irqqueue))
		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
				       queue);
	else
		queue->flags |= UVC_QUEUE_PAUSED;

	return buf;
}

Privacy Policy