forked from v4l2loopback/v4l2loopback
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathv4l2loopback.c
3313 lines (2915 loc) · 93.9 KB
/
v4l2loopback.c
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
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* -*- c-file-style: "linux" -*- */
/*
* v4l2loopback.c -- video4linux2 loopback driver
*
* Copyright (C) 2005-2009 Vasily Levin (vasaka@gmail.com)
* Copyright (C) 2010-2023 IOhannes m zmoelnig (zmoelnig@iem.at)
* Copyright (C) 2011 Stefan Diewald (stefan.diewald@mytum.de)
* Copyright (C) 2012 Anton Novikov (random.plant@gmail.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/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/module.h>
#include <linux/videodev2.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/capability.h>
#include <linux/eventpoll.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-event.h>
#include <linux/miscdevice.h>
#include "v4l2loopback.h"
#define V4L2LOOPBACK_CTL_ADD_legacy 0x4C80
#define V4L2LOOPBACK_CTL_REMOVE_legacy 0x4C81
#define V4L2LOOPBACK_CTL_QUERY_legacy 0x4C82
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 0, 0)
#error This module is not supported on kernels before 4.0.0.
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
#define strscpy strlcpy
#endif
#if defined(timer_setup) && defined(from_timer)
#define HAVE_TIMER_SETUP
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 7, 0)
#define VFL_TYPE_VIDEO VFL_TYPE_GRABBER
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 2, 0)
#define timer_delete_sync del_timer_sync
#endif
#define V4L2LOOPBACK_VERSION_CODE \
KERNEL_VERSION(V4L2LOOPBACK_VERSION_MAJOR, V4L2LOOPBACK_VERSION_MINOR, \
V4L2LOOPBACK_VERSION_BUGFIX)
MODULE_DESCRIPTION("V4L2 loopback video device");
MODULE_AUTHOR("Vasily Levin, "
"IOhannes m zmoelnig <zmoelnig@iem.at>,"
"Stefan Diewald,"
"Anton Novikov"
"et al.");
#ifdef SNAPSHOT_VERSION
MODULE_VERSION(__stringify(SNAPSHOT_VERSION));
#else
MODULE_VERSION("" __stringify(V4L2LOOPBACK_VERSION_MAJOR) "." __stringify(
V4L2LOOPBACK_VERSION_MINOR) "." __stringify(V4L2LOOPBACK_VERSION_BUGFIX));
#endif
MODULE_LICENSE("GPL");
/*
* helpers
*/
#define dprintk(fmt, args...) \
do { \
if (debug > 0) { \
printk(KERN_INFO "v4l2-loopback[" __stringify( \
__LINE__) "], pid(%d): " fmt, \
task_pid_nr(current), ##args); \
} \
} while (0)
#define MARK() \
do { \
if (debug > 1) { \
printk(KERN_INFO "%s:%d[%s], pid(%d)\n", __FILE__, \
__LINE__, __func__, task_pid_nr(current)); \
} \
} while (0)
#define dprintkrw(fmt, args...) \
do { \
if (debug > 2) { \
printk(KERN_INFO "v4l2-loopback[" __stringify( \
__LINE__) "], pid(%d): " fmt, \
task_pid_nr(current), ##args); \
} \
} while (0)
static inline void v4l2l_get_timestamp(struct v4l2_buffer *b)
{
struct timespec64 ts;
ktime_get_ts64(&ts);
b->timestamp.tv_sec = ts.tv_sec;
b->timestamp.tv_usec = (ts.tv_nsec / NSEC_PER_USEC);
b->flags |= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
b->flags &= ~V4L2_BUF_FLAG_TIMESTAMP_COPY;
}
#if BITS_PER_LONG == 32
#include <asm/div64.h> /* do_div() for 64bit division */
static inline int v4l2l_mod64(const s64 A, const u32 B)
{
u64 a = (u64)A;
u32 b = B;
if (A > 0)
return do_div(a, b);
a = -A;
return -do_div(a, b);
}
#else
static inline int v4l2l_mod64(const s64 A, const u32 B)
{
return A % B;
}
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 16, 0)
typedef unsigned __poll_t;
#endif
/* module constants
* can be overridden during he build process using something like
* make KCPPFLAGS="-DMAX_DEVICES=100"
*/
/* maximum number of v4l2loopback devices that can be created */
#ifndef MAX_DEVICES
#define MAX_DEVICES 8
#endif
/* whether the default is to announce capabilities exclusively or not */
#ifndef V4L2LOOPBACK_DEFAULT_EXCLUSIVECAPS
#define V4L2LOOPBACK_DEFAULT_EXCLUSIVECAPS 0
#endif
/* when a producer is considered to have gone stale */
#ifndef MAX_TIMEOUT
#define MAX_TIMEOUT (100 * 1000) /* in msecs */
#endif
/* max buffers that can be mapped, actually they
* are all mapped to max_buffers buffers */
#ifndef MAX_BUFFERS
#define MAX_BUFFERS 32
#endif
/* module parameters */
static int debug = 0;
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "debugging level (higher values == more verbose)");
#define V4L2LOOPBACK_DEFAULT_MAX_BUFFERS 2
static int max_buffers = V4L2LOOPBACK_DEFAULT_MAX_BUFFERS;
module_param(max_buffers, int, S_IRUGO);
MODULE_PARM_DESC(max_buffers,
"how many buffers should be allocated [DEFAULT: " __stringify(
V4L2LOOPBACK_DEFAULT_MAX_BUFFERS) "]");
/* how many times a device can be opened
* the per-module default value can be overridden on a per-device basis using
* the /sys/devices interface
*
* note that max_openers should be at least 2 in order to get a working system:
* one opener for the producer and one opener for the consumer
* however, we leave that to the user
*/
#define V4L2LOOPBACK_DEFAULT_MAX_OPENERS 10
static int max_openers = V4L2LOOPBACK_DEFAULT_MAX_OPENERS;
module_param(max_openers, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(
max_openers,
"how many users can open the loopback device [DEFAULT: " __stringify(
V4L2LOOPBACK_DEFAULT_MAX_OPENERS) "]");
static int devices = -1;
module_param(devices, int, 0);
MODULE_PARM_DESC(devices, "how many devices should be created");
static int video_nr[MAX_DEVICES] = { [0 ...(MAX_DEVICES - 1)] = -1 };
module_param_array(video_nr, int, NULL, 0444);
MODULE_PARM_DESC(video_nr,
"video device numbers (-1=auto, 0=/dev/video0, etc.)");
static char *card_label[MAX_DEVICES];
module_param_array(card_label, charp, NULL, 0000);
MODULE_PARM_DESC(card_label, "card labels for each device");
static bool exclusive_caps[MAX_DEVICES] = {
[0 ...(MAX_DEVICES - 1)] = V4L2LOOPBACK_DEFAULT_EXCLUSIVECAPS
};
module_param_array(exclusive_caps, bool, NULL, 0444);
/* FIXXME: wording */
MODULE_PARM_DESC(
exclusive_caps,
"whether to announce OUTPUT/CAPTURE capabilities exclusively or not [DEFAULT: " __stringify(
V4L2LOOPBACK_DEFAULT_EXCLUSIVECAPS) "]");
/* format specifications */
#define V4L2LOOPBACK_SIZE_MIN_WIDTH 2
#define V4L2LOOPBACK_SIZE_MIN_HEIGHT 1
#define V4L2LOOPBACK_SIZE_DEFAULT_MAX_WIDTH 8192
#define V4L2LOOPBACK_SIZE_DEFAULT_MAX_HEIGHT 8192
#define V4L2LOOPBACK_SIZE_DEFAULT_WIDTH 640
#define V4L2LOOPBACK_SIZE_DEFAULT_HEIGHT 480
static int max_width = V4L2LOOPBACK_SIZE_DEFAULT_MAX_WIDTH;
module_param(max_width, int, S_IRUGO);
MODULE_PARM_DESC(max_width,
"maximum allowed frame width [DEFAULT: " __stringify(
V4L2LOOPBACK_SIZE_DEFAULT_MAX_WIDTH) "]");
static int max_height = V4L2LOOPBACK_SIZE_DEFAULT_MAX_HEIGHT;
module_param(max_height, int, S_IRUGO);
MODULE_PARM_DESC(max_height,
"maximum allowed frame height [DEFAULT: " __stringify(
V4L2LOOPBACK_SIZE_DEFAULT_MAX_HEIGHT) "]");
static DEFINE_IDR(v4l2loopback_index_idr);
static DEFINE_MUTEX(v4l2loopback_ctl_mutex);
/* frame intervals */
#define V4L2LOOPBACK_FRAME_INTERVAL_MAX __UINT32_MAX__
#define V4L2LOOPBACK_FPS_DEFAULT 30
#define V4L2LOOPBACK_FPS_MAX 1000
/* control IDs */
#define V4L2LOOPBACK_CID_BASE (V4L2_CID_USER_BASE | 0xf000)
#define CID_KEEP_FORMAT (V4L2LOOPBACK_CID_BASE + 0)
#define CID_SUSTAIN_FRAMERATE (V4L2LOOPBACK_CID_BASE + 1)
#define CID_TIMEOUT (V4L2LOOPBACK_CID_BASE + 2)
#define CID_TIMEOUT_IMAGE_IO (V4L2LOOPBACK_CID_BASE + 3)
static int v4l2loopback_s_ctrl(struct v4l2_ctrl *ctrl);
static const struct v4l2_ctrl_ops v4l2loopback_ctrl_ops = {
.s_ctrl = v4l2loopback_s_ctrl,
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_keepformat = {
// clang-format off
.ops = &v4l2loopback_ctrl_ops,
.id = CID_KEEP_FORMAT,
.name = "keep_format",
.type = V4L2_CTRL_TYPE_BOOLEAN,
.min = 0,
.max = 1,
.step = 1,
.def = 0,
// clang-format on
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_sustainframerate = {
// clang-format off
.ops = &v4l2loopback_ctrl_ops,
.id = CID_SUSTAIN_FRAMERATE,
.name = "sustain_framerate",
.type = V4L2_CTRL_TYPE_BOOLEAN,
.min = 0,
.max = 1,
.step = 1,
.def = 0,
// clang-format on
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_timeout = {
// clang-format off
.ops = &v4l2loopback_ctrl_ops,
.id = CID_TIMEOUT,
.name = "timeout",
.type = V4L2_CTRL_TYPE_INTEGER,
.min = 0,
.max = MAX_TIMEOUT,
.step = 1,
.def = 0,
// clang-format on
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_timeoutimageio = {
// clang-format off
.ops = &v4l2loopback_ctrl_ops,
.id = CID_TIMEOUT_IMAGE_IO,
.name = "timeout_image_io",
.type = V4L2_CTRL_TYPE_BUTTON,
.min = 0,
.max = 0,
.step = 0,
.def = 0,
// clang-format on
};
/* module structures */
struct v4l2loopback_private {
int device_nr;
};
/* TODO(vasaka) use typenames which are common to kernel, but first find out if
* it is needed */
/* struct keeping state and settings of loopback device */
struct v4l2l_buffer {
struct v4l2_buffer buffer;
struct list_head list_head;
atomic_t use_count;
};
struct v4l2_loopback_device {
struct v4l2_device v4l2_dev;
struct v4l2_ctrl_handler ctrl_handler;
struct video_device *vdev;
/* loopback device-specific parameters */
char card_label[32];
bool announce_all_caps; /* announce both OUTPUT and CAPTURE capabilities
* when true; else announce OUTPUT when no
* writer is streaming, otherwise CAPTURE. */
int max_openers; /* how many times can this device be opened */
int min_width, max_width;
int min_height, max_height;
/* pixel and stream format */
struct v4l2_pix_format pix_format;
bool pix_format_has_valid_sizeimage;
struct v4l2_captureparm capture_param;
unsigned long frame_jiffies;
/* ctrls */
int keep_format; /* CID_KEEP_FORMAT; lock the format, do not free
* on close(), and when `!announce_all_caps` do NOT
* fall back to OUTPUT when no writers attached (clear
* `keep_format` to attach a new writer) */
int sustain_framerate; /* CID_SUSTAIN_FRAMERATE; duplicate frames to maintain
(close to) nominal framerate */
unsigned long timeout_jiffies; /* CID_TIMEOUT; 0 means disabled */
int timeout_image_io; /* CID_TIMEOUT_IMAGE_IO; next opener will
* queue/dequeue the timeout image buffer */
/* buffers for OUTPUT and CAPTURE */
u8 *image; /* pointer to actual buffers data */
unsigned long image_size; /* number of bytes alloc'd for all buffers */
struct v4l2l_buffer buffers[MAX_BUFFERS]; /* inner driver buffers */
u32 buffer_count; /* should not be big, 4 is a good choice */
u32 buffer_size; /* number of bytes alloc'd per buffer */
u32 used_buffer_count; /* number of buffers allocated to openers */
struct list_head outbufs_list; /* FIFO queue for OUTPUT buffers */
u32 bufpos2index[MAX_BUFFERS]; /* mapping of `(position % used_buffers)`
* to `buffers[index]` */
s64 write_position; /* sequence number of last 'displayed' buffer plus
* one */
/* synchronization between openers */
atomic_t open_count;
struct mutex image_mutex; /* mutex for allocating image(s) and
* exchanging format tokens */
spinlock_t lock; /* lock for the timeout and framerate timers */
spinlock_t list_lock; /* lock for the OUTPUT buffer queue */
wait_queue_head_t read_event;
u32 format_tokens; /* tokens to 'set format' for OUTPUT, CAPTURE, or
* timeout buffers */
u32 stream_tokens; /* tokens to 'start' OUTPUT, CAPTURE, or timeout
* stream */
/* sustain framerate */
struct timer_list sustain_timer;
unsigned int reread_count;
/* timeout */
u8 *timeout_image; /* copied to outgoing buffers when timeout passes */
struct v4l2l_buffer timeout_buffer;
u32 timeout_buffer_size; /* number bytes alloc'd for timeout buffer */
struct timer_list timeout_timer;
int timeout_happened;
};
enum v4l2l_io_method {
V4L2L_IO_NONE = 0,
V4L2L_IO_MMAP = 1,
V4L2L_IO_FILE = 2,
V4L2L_IO_TIMEOUT = 3,
};
/* struct keeping state and type of opener */
struct v4l2_loopback_opener {
u32 format_token; /* token (if any) for type used in call to S_FMT or
* REQBUFS */
u32 stream_token; /* token (if any) for type used in call to STREAMON */
u32 buffer_count; /* number of buffers (if any) that opener acquired via
* REQBUFS */
s64 read_position; /* sequence number of the next 'captured' frame */
unsigned int reread_count;
enum v4l2l_io_method io_method;
struct v4l2_fh fh;
};
#define fh_to_opener(ptr) container_of((ptr), struct v4l2_loopback_opener, fh)
/* this is heavily inspired by the bttv driver found in the linux kernel */
struct v4l2l_format {
char *name;
int fourcc; /* video4linux 2 */
int depth; /* bit/pixel */
int flags;
};
/* set the v4l2l_format.flags to PLANAR for non-packed formats */
#define FORMAT_FLAGS_PLANAR 0x01
#define FORMAT_FLAGS_COMPRESSED 0x02
#include "v4l2loopback_formats.h"
#ifndef V4L2_TYPE_IS_CAPTURE
#define V4L2_TYPE_IS_CAPTURE(type) \
((type) == V4L2_BUF_TYPE_VIDEO_CAPTURE || \
(type) == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
#endif /* V4L2_TYPE_IS_CAPTURE */
#ifndef V4L2_TYPE_IS_OUTPUT
#define V4L2_TYPE_IS_OUTPUT(type) \
((type) == V4L2_BUF_TYPE_VIDEO_OUTPUT || \
(type) == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
#endif /* V4L2_TYPE_IS_OUTPUT */
/* token values for privilege to set format or start/stop stream */
#define V4L2L_TOKEN_CAPTURE 0x01
#define V4L2L_TOKEN_OUTPUT 0x02
#define V4L2L_TOKEN_TIMEOUT 0x04
#define V4L2L_TOKEN_MASK \
(V4L2L_TOKEN_CAPTURE | V4L2L_TOKEN_OUTPUT | V4L2L_TOKEN_TIMEOUT)
/* helpers for token exchange and token status */
#define token_from_type(type) \
(V4L2_TYPE_IS_CAPTURE(type) ? V4L2L_TOKEN_CAPTURE : V4L2L_TOKEN_OUTPUT)
#define acquire_token(dev, opener, label, token) \
do { \
(opener)->label##_token = token; \
(dev)->label##_tokens &= ~token; \
} while (0)
#define release_token(dev, opener, label) \
do { \
(dev)->label##_tokens |= (opener)->label##_token; \
(opener)->label##_token = 0; \
} while (0)
#define has_output_token(token) (token & V4L2L_TOKEN_OUTPUT)
#define has_capture_token(token) (token & V4L2L_TOKEN_CAPTURE)
#define has_no_owners(dev) ((~((dev)->format_tokens) & V4L2L_TOKEN_MASK) == 0)
#define has_other_owners(opener, dev) \
(~((dev)->format_tokens ^ (opener)->format_token) & V4L2L_TOKEN_MASK)
#define need_timeout_buffer(dev, token) \
((dev)->timeout_jiffies > 0 || (token) & V4L2L_TOKEN_TIMEOUT)
static const unsigned int FORMATS = ARRAY_SIZE(formats);
static char *fourcc2str(unsigned int fourcc, char buf[5])
{
buf[0] = (fourcc >> 0) & 0xFF;
buf[1] = (fourcc >> 8) & 0xFF;
buf[2] = (fourcc >> 16) & 0xFF;
buf[3] = (fourcc >> 24) & 0xFF;
buf[4] = 0;
return buf;
}
static const struct v4l2l_format *format_by_fourcc(int fourcc)
{
unsigned int i;
char buf[5];
for (i = 0; i < FORMATS; i++) {
if (formats[i].fourcc == fourcc)
return formats + i;
}
dprintk("unsupported format '%4s'\n", fourcc2str(fourcc, buf));
return NULL;
}
static void pix_format_set_size(struct v4l2_pix_format *f,
const struct v4l2l_format *fmt,
unsigned int width, unsigned int height)
{
f->width = width;
f->height = height;
if (fmt->flags & FORMAT_FLAGS_PLANAR) {
f->bytesperline = width; /* Y plane */
f->sizeimage = (width * height * fmt->depth) >> 3;
} else if (fmt->flags & FORMAT_FLAGS_COMPRESSED) {
/* doesn't make sense for compressed formats */
f->bytesperline = 0;
f->sizeimage = (width * height * fmt->depth) >> 3;
} else {
f->bytesperline = (width * fmt->depth) >> 3;
f->sizeimage = height * f->bytesperline;
}
}
static int v4l2l_fill_format(struct v4l2_format *fmt, const u32 minwidth,
const u32 maxwidth, const u32 minheight,
const u32 maxheight)
{
u32 width = fmt->fmt.pix.width, height = fmt->fmt.pix.height;
u32 pixelformat = fmt->fmt.pix.pixelformat;
struct v4l2_format fmt0 = *fmt;
u32 bytesperline = 0, sizeimage = 0;
if (!width)
width = V4L2LOOPBACK_SIZE_DEFAULT_WIDTH;
if (!height)
height = V4L2LOOPBACK_SIZE_DEFAULT_HEIGHT;
width = clamp_val(width, minwidth, maxwidth);
height = clamp_val(height, minheight, maxheight);
/* sets: width,height,pixelformat,bytesperline,sizeimage */
if (!(V4L2_TYPE_IS_MULTIPLANAR(fmt0.type))) {
fmt0.fmt.pix.bytesperline = 0;
fmt0.fmt.pix.sizeimage = 0;
}
if (0) {
;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 2, 0)
} else if (!v4l2_fill_pixfmt(&fmt0.fmt.pix, pixelformat, width,
height)) {
;
} else if (!v4l2_fill_pixfmt_mp(&fmt0.fmt.pix_mp, pixelformat, width,
height)) {
;
#endif
} else {
const struct v4l2l_format *format =
format_by_fourcc(pixelformat);
if (!format)
return -EINVAL;
pix_format_set_size(&fmt0.fmt.pix, format, width, height);
fmt0.fmt.pix.pixelformat = format->fourcc;
}
if (V4L2_TYPE_IS_MULTIPLANAR(fmt0.type)) {
*fmt = fmt0;
if ((fmt->fmt.pix_mp.colorspace == V4L2_COLORSPACE_DEFAULT) ||
(fmt->fmt.pix_mp.colorspace > V4L2_COLORSPACE_DCI_P3))
fmt->fmt.pix_mp.colorspace = V4L2_COLORSPACE_SRGB;
if (V4L2_FIELD_ANY == fmt->fmt.pix_mp.field)
fmt->fmt.pix_mp.field = V4L2_FIELD_NONE;
} else {
bytesperline = fmt->fmt.pix.bytesperline;
sizeimage = fmt->fmt.pix.sizeimage;
*fmt = fmt0;
if (!fmt->fmt.pix.bytesperline)
fmt->fmt.pix.bytesperline = bytesperline;
if (!fmt->fmt.pix.sizeimage)
fmt->fmt.pix.sizeimage = sizeimage;
if ((fmt->fmt.pix.colorspace == V4L2_COLORSPACE_DEFAULT) ||
(fmt->fmt.pix.colorspace > V4L2_COLORSPACE_DCI_P3))
fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
if (V4L2_FIELD_ANY == fmt->fmt.pix.field)
fmt->fmt.pix.field = V4L2_FIELD_NONE;
}
return 0;
}
/* Checks if v4l2l_fill_format() has set a valid, fixed sizeimage val. */
static bool v4l2l_pix_format_has_valid_sizeimage(struct v4l2_format *fmt)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 2, 0)
const struct v4l2_format_info *info;
info = v4l2_format_info(fmt->fmt.pix.pixelformat);
if (info && info->mem_planes == 1)
return true;
#endif
return false;
}
static int pix_format_eq(const struct v4l2_pix_format *ref,
const struct v4l2_pix_format *tgt, int strict)
{
/* check if the two formats are equivalent.
* ANY fields are handled gracefully
*/
#define _pix_format_eq0(x) \
if (ref->x != tgt->x) \
result = 0
#define _pix_format_eq1(x, def) \
do { \
if ((def != tgt->x) && (ref->x != tgt->x)) { \
printk(KERN_INFO #x " failed"); \
result = 0; \
} \
} while (0)
int result = 1;
_pix_format_eq0(width);
_pix_format_eq0(height);
_pix_format_eq0(pixelformat);
if (!strict)
return result;
_pix_format_eq1(field, V4L2_FIELD_ANY);
_pix_format_eq0(bytesperline);
_pix_format_eq0(sizeimage);
_pix_format_eq1(colorspace, V4L2_COLORSPACE_DEFAULT);
return result;
}
static void set_timeperframe(struct v4l2_loopback_device *dev,
struct v4l2_fract *tpf)
{
if (!tpf->denominator && !tpf->numerator) {
tpf->numerator = 1;
tpf->denominator = V4L2LOOPBACK_FPS_DEFAULT;
} else if (tpf->numerator >
V4L2LOOPBACK_FRAME_INTERVAL_MAX * tpf->denominator) {
/* divide-by-zero or greater than maximum interval => min FPS */
tpf->numerator = V4L2LOOPBACK_FRAME_INTERVAL_MAX;
tpf->denominator = 1;
} else if (tpf->numerator * V4L2LOOPBACK_FPS_MAX < tpf->denominator) {
/* zero or lower than minimum interval => max FPS */
tpf->numerator = 1;
tpf->denominator = V4L2LOOPBACK_FPS_MAX;
}
dev->capture_param.timeperframe = *tpf;
dev->frame_jiffies =
max(1UL, (msecs_to_jiffies(1000) * tpf->numerator) /
tpf->denominator);
}
static struct v4l2_loopback_device *v4l2loopback_cd2dev(struct device *cd);
/* device attributes */
/* available via sysfs: /sys/devices/virtual/video4linux/video* */
static ssize_t attr_show_format(struct device *cd,
struct device_attribute *attr, char *buf)
{
/* gets the current format as "FOURCC:WxH@f/s", e.g. "YUYV:320x240@1000/30" */
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
const struct v4l2_fract *tpf;
char buf4cc[5], buf_fps[32];
if (!dev || (has_no_owners(dev) && !dev->keep_format))
return 0;
tpf = &dev->capture_param.timeperframe;
fourcc2str(dev->pix_format.pixelformat, buf4cc);
if (tpf->numerator == 1)
snprintf(buf_fps, sizeof(buf_fps), "%u", tpf->denominator);
else
snprintf(buf_fps, sizeof(buf_fps), "%u/%u", tpf->denominator,
tpf->numerator);
return sprintf(buf, "%4s:%ux%u@%s\n", buf4cc, dev->pix_format.width,
dev->pix_format.height, buf_fps);
}
static ssize_t attr_store_format(struct device *cd,
struct device_attribute *attr, const char *buf,
size_t len)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
int fps_num = 0, fps_den = 1;
if (!dev)
return -ENODEV;
/* only fps changing is supported */
if (sscanf(buf, "@%u/%u", &fps_num, &fps_den) > 0) {
struct v4l2_fract f = { .numerator = fps_den,
.denominator = fps_num };
set_timeperframe(dev, &f);
return len;
}
return -EINVAL;
}
static DEVICE_ATTR(format, S_IRUGO | S_IWUSR, attr_show_format,
attr_store_format);
static ssize_t attr_show_buffers(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
if (!dev)
return -ENODEV;
return sprintf(buf, "%u\n", dev->used_buffer_count);
}
static DEVICE_ATTR(buffers, S_IRUGO, attr_show_buffers, NULL);
static ssize_t attr_show_maxopeners(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
if (!dev)
return -ENODEV;
return sprintf(buf, "%d\n", dev->max_openers);
}
static ssize_t attr_store_maxopeners(struct device *cd,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct v4l2_loopback_device *dev = NULL;
unsigned long curr = 0;
if (kstrtoul(buf, 0, &curr))
return -EINVAL;
dev = v4l2loopback_cd2dev(cd);
if (!dev)
return -ENODEV;
if (dev->max_openers == curr)
return len;
if (curr > __INT_MAX__ || dev->open_count.counter > curr) {
/* request to limit to less openers as are currently attached to us */
return -EINVAL;
}
dev->max_openers = (int)curr;
return len;
}
static DEVICE_ATTR(max_openers, S_IRUGO | S_IWUSR, attr_show_maxopeners,
attr_store_maxopeners);
static ssize_t attr_show_state(struct device *cd, struct device_attribute *attr,
char *buf)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
if (!dev)
return -ENODEV;
if (!has_output_token(dev->stream_tokens) || dev->keep_format) {
return sprintf(buf, "capture\n");
} else
return sprintf(buf, "output\n");
return -EAGAIN;
}
static DEVICE_ATTR(state, S_IRUGO, attr_show_state, NULL);
static void v4l2loopback_remove_sysfs(struct video_device *vdev)
{
#define V4L2_SYSFS_DESTROY(x) device_remove_file(&vdev->dev, &dev_attr_##x)
if (vdev) {
V4L2_SYSFS_DESTROY(format);
V4L2_SYSFS_DESTROY(buffers);
V4L2_SYSFS_DESTROY(max_openers);
V4L2_SYSFS_DESTROY(state);
/* ... */
}
}
static void v4l2loopback_create_sysfs(struct video_device *vdev)
{
int res = 0;
#define V4L2_SYSFS_CREATE(x) \
res = device_create_file(&vdev->dev, &dev_attr_##x); \
if (res < 0) \
break
if (!vdev)
return;
do {
V4L2_SYSFS_CREATE(format);
V4L2_SYSFS_CREATE(buffers);
V4L2_SYSFS_CREATE(max_openers);
V4L2_SYSFS_CREATE(state);
/* ... */
} while (0);
if (res >= 0)
return;
dev_err(&vdev->dev, "%s error: %d\n", __func__, res);
}
/* Event APIs */
#define V4L2LOOPBACK_EVENT_BASE (V4L2_EVENT_PRIVATE_START)
#define V4L2LOOPBACK_EVENT_OFFSET 0x08E00000
#define V4L2_EVENT_PRI_CLIENT_USAGE \
(V4L2LOOPBACK_EVENT_BASE + V4L2LOOPBACK_EVENT_OFFSET + 1)
struct v4l2_event_client_usage {
__u32 count;
};
/* global module data */
/* find a device based on it's device-number (e.g. '3' for /dev/video3) */
struct v4l2loopback_lookup_cb_data {
int device_nr;
struct v4l2_loopback_device *device;
};
static int v4l2loopback_lookup_cb(int id, void *ptr, void *data)
{
struct v4l2_loopback_device *device = ptr;
struct v4l2loopback_lookup_cb_data *cbdata = data;
if (cbdata && device && device->vdev) {
if (device->vdev->num == cbdata->device_nr) {
cbdata->device = device;
cbdata->device_nr = id;
return 1;
}
}
return 0;
}
static int v4l2loopback_lookup(int device_nr,
struct v4l2_loopback_device **device)
{
struct v4l2loopback_lookup_cb_data data = {
.device_nr = device_nr,
.device = NULL,
};
int err = idr_for_each(&v4l2loopback_index_idr, &v4l2loopback_lookup_cb,
&data);
if (1 == err) {
if (device)
*device = data.device;
return data.device_nr;
}
return -ENODEV;
}
#define v4l2loopback_get_vdev_nr(vdev) \
((struct v4l2loopback_private *)video_get_drvdata(vdev))->device_nr
static struct v4l2_loopback_device *v4l2loopback_cd2dev(struct device *cd)
{
struct video_device *loopdev = to_video_device(cd);
int device_nr = v4l2loopback_get_vdev_nr(loopdev);
return idr_find(&v4l2loopback_index_idr, device_nr);
}
static struct v4l2_loopback_device *v4l2loopback_getdevice(struct file *f)
{
struct v4l2loopback_private *ptr = video_drvdata(f);
int nr = ptr->device_nr;
return idr_find(&v4l2loopback_index_idr, nr);
}
/* forward declarations */
static void client_usage_queue_event(struct video_device *vdev);
static bool any_buffers_mapped(struct v4l2_loopback_device *dev);
static int allocate_buffers(struct v4l2_loopback_device *dev,
struct v4l2_pix_format *pix_format);
static void init_buffers(struct v4l2_loopback_device *dev, u32 bytes_used,
u32 buffer_size);
static void free_buffers(struct v4l2_loopback_device *dev);
static int allocate_timeout_buffer(struct v4l2_loopback_device *dev);
static void free_timeout_buffer(struct v4l2_loopback_device *dev);
static void check_timers(struct v4l2_loopback_device *dev);
static const struct v4l2_file_operations v4l2_loopback_fops;
static const struct v4l2_ioctl_ops v4l2_loopback_ioctl_ops;
/* V4L2 ioctl caps and params calls */
/* returns device capabilities
* called on VIDIOC_QUERYCAP
*/
static int vidioc_querycap(struct file *file, void *fh,
struct v4l2_capability *cap)
{
struct v4l2_loopback_device *dev = v4l2loopback_getdevice(file);
struct v4l2_loopback_opener *opener = fh_to_opener(fh);
int device_nr = v4l2loopback_get_vdev_nr(dev->vdev);
__u32 capabilities = V4L2_CAP_STREAMING | V4L2_CAP_READWRITE;
strscpy(cap->driver, "v4l2 loopback", sizeof(cap->driver));
snprintf(cap->card, sizeof(cap->card), "%s", dev->card_label);
snprintf(cap->bus_info, sizeof(cap->bus_info),
"platform:v4l2loopback-%03d", device_nr);
if (dev->announce_all_caps) {
capabilities |= V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_OUTPUT;
} else {
if (opener->io_method == V4L2L_IO_TIMEOUT ||
(has_output_token(dev->stream_tokens) &&
!dev->keep_format)) {
capabilities |= V4L2_CAP_VIDEO_OUTPUT;
} else
capabilities |= V4L2_CAP_VIDEO_CAPTURE;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
dev->vdev->device_caps =
#endif /* >=linux-4.7.0 */
cap->device_caps = cap->capabilities = capabilities;
cap->capabilities |= V4L2_CAP_DEVICE_CAPS;
memset(cap->reserved, 0, sizeof(cap->reserved));
return 0;
}
static int vidioc_enum_framesizes(struct file *file, void *fh,
struct v4l2_frmsizeenum *argp)
{
struct v4l2_loopback_device *dev = v4l2loopback_getdevice(file);
struct v4l2_loopback_opener *opener = fh_to_opener(fh);
/* there can be only one... */
if (argp->index)
return -EINVAL;
if (dev->keep_format || has_other_owners(opener, dev)) {
/* only current frame size supported */
if (argp->pixel_format != dev->pix_format.pixelformat)
return -EINVAL;
argp->type = V4L2_FRMSIZE_TYPE_DISCRETE;
argp->discrete.width = dev->pix_format.width;
argp->discrete.height = dev->pix_format.height;
} else {
/* return continuous sizes if pixel format is supported */
if (NULL == format_by_fourcc(argp->pixel_format))
return -EINVAL;
if (dev->min_width == dev->max_width &&
dev->min_height == dev->max_height) {
argp->type = V4L2_FRMSIZE_TYPE_DISCRETE;
argp->discrete.width = dev->min_width;
argp->discrete.height = dev->min_height;
} else {
argp->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
argp->stepwise.min_width = dev->min_width;
argp->stepwise.min_height = dev->min_height;
argp->stepwise.max_width = dev->max_width;
argp->stepwise.max_height = dev->max_height;
argp->stepwise.step_width = 1;
argp->stepwise.step_height = 1;
}
}
return 0;
}
/* Test if the device is currently 'capable' of the buffer (stream) type when
* the `exclusive_caps` parameter is set. `keep_format` should lock the format
* and prevent free of buffers */
static int check_buffer_capability(struct v4l2_loopback_device *dev,
struct v4l2_loopback_opener *opener,
enum v4l2_buf_type type)
{
/* short-circuit for (non-compliant) timeout image mode */
if (opener->io_method == V4L2L_IO_TIMEOUT)
return 0;
if (dev->announce_all_caps)
return (type == V4L2_BUF_TYPE_VIDEO_CAPTURE ||
type == V4L2_BUF_TYPE_VIDEO_OUTPUT) ?
0 :
-EINVAL;
/* CAPTURE if opener has a capture format or a writer is streaming;
* else OUTPUT. */
switch (type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
if (!(has_capture_token(opener->format_token) ||
!has_output_token(dev->stream_tokens)))
return -EINVAL;
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
if (!(has_output_token(opener->format_token) ||
has_output_token(dev->stream_tokens)))
return -EINVAL;
break;
default:
return -EINVAL;
}
return 0;
}