Merge tag 'devicetree-for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-block.git] / drivers / media / v4l2-core / videobuf-core.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * generic helper functions for handling video4linux capture buffers
4  *
5  * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
6  *
7  * Highly based on video-buf written originally by:
8  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
9  * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
10  * (c) 2006 Ted Walther and John Sokol
11  */
12
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/mm.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/interrupt.h>
20
21 #include <media/videobuf-core.h>
22 #include <media/v4l2-common.h>
23
24 #define MAGIC_BUFFER 0x20070728
25 #define MAGIC_CHECK(is, should)                                         \
26         do {                                                            \
27                 if (unlikely((is) != (should))) {                       \
28                         printk(KERN_ERR                                 \
29                                 "magic mismatch: %x (expected %x)\n",   \
30                                         is, should);                    \
31                         BUG();                                          \
32                 }                                                       \
33         } while (0)
34
35 static int debug;
36 module_param(debug, int, 0644);
37
38 MODULE_DESCRIPTION("helper module to manage video4linux buffers");
39 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
40 MODULE_LICENSE("GPL");
41
42 #define dprintk(level, fmt, arg...)                                     \
43         do {                                                            \
44                 if (debug >= level)                                     \
45                         printk(KERN_DEBUG "vbuf: " fmt, ## arg);        \
46         } while (0)
47
48 /* --------------------------------------------------------------------- */
49
50 #define CALL(q, f, arg...)                                              \
51         ((q->int_ops->f) ? q->int_ops->f(arg) : 0)
52 #define CALLPTR(q, f, arg...)                                           \
53         ((q->int_ops->f) ? q->int_ops->f(arg) : NULL)
54
55 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
56 {
57         struct videobuf_buffer *vb;
58
59         BUG_ON(q->msize < sizeof(*vb));
60
61         if (!q->int_ops || !q->int_ops->alloc_vb) {
62                 printk(KERN_ERR "No specific ops defined!\n");
63                 BUG();
64         }
65
66         vb = q->int_ops->alloc_vb(q->msize);
67         if (NULL != vb) {
68                 init_waitqueue_head(&vb->done);
69                 vb->magic = MAGIC_BUFFER;
70         }
71
72         return vb;
73 }
74 EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
75
76 static int state_neither_active_nor_queued(struct videobuf_queue *q,
77                                            struct videobuf_buffer *vb)
78 {
79         unsigned long flags;
80         bool rc;
81
82         spin_lock_irqsave(q->irqlock, flags);
83         rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
84         spin_unlock_irqrestore(q->irqlock, flags);
85         return rc;
86 };
87
88 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
89                 int non_blocking, int intr)
90 {
91         bool is_ext_locked;
92         int ret = 0;
93
94         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
95
96         if (non_blocking) {
97                 if (state_neither_active_nor_queued(q, vb))
98                         return 0;
99                 return -EAGAIN;
100         }
101
102         is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
103
104         /* Release vdev lock to prevent this wait from blocking outside access to
105            the device. */
106         if (is_ext_locked)
107                 mutex_unlock(q->ext_lock);
108         if (intr)
109                 ret = wait_event_interruptible(vb->done,
110                                         state_neither_active_nor_queued(q, vb));
111         else
112                 wait_event(vb->done, state_neither_active_nor_queued(q, vb));
113         /* Relock */
114         if (is_ext_locked)
115                 mutex_lock(q->ext_lock);
116
117         return ret;
118 }
119 EXPORT_SYMBOL_GPL(videobuf_waiton);
120
121 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
122                     struct v4l2_framebuffer *fbuf)
123 {
124         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
125         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
126
127         return CALL(q, iolock, q, vb, fbuf);
128 }
129 EXPORT_SYMBOL_GPL(videobuf_iolock);
130
131 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
132                               struct videobuf_buffer *buf)
133 {
134         if (q->int_ops->vaddr)
135                 return q->int_ops->vaddr(buf);
136         return NULL;
137 }
138 EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
139
140 /* --------------------------------------------------------------------- */
141
142
143 void videobuf_queue_core_init(struct videobuf_queue *q,
144                          const struct videobuf_queue_ops *ops,
145                          struct device *dev,
146                          spinlock_t *irqlock,
147                          enum v4l2_buf_type type,
148                          enum v4l2_field field,
149                          unsigned int msize,
150                          void *priv,
151                          struct videobuf_qtype_ops *int_ops,
152                          struct mutex *ext_lock)
153 {
154         BUG_ON(!q);
155         memset(q, 0, sizeof(*q));
156         q->irqlock   = irqlock;
157         q->ext_lock  = ext_lock;
158         q->dev       = dev;
159         q->type      = type;
160         q->field     = field;
161         q->msize     = msize;
162         q->ops       = ops;
163         q->priv_data = priv;
164         q->int_ops   = int_ops;
165
166         /* All buffer operations are mandatory */
167         BUG_ON(!q->ops->buf_setup);
168         BUG_ON(!q->ops->buf_prepare);
169         BUG_ON(!q->ops->buf_queue);
170         BUG_ON(!q->ops->buf_release);
171
172         /* Lock is mandatory for queue_cancel to work */
173         BUG_ON(!irqlock);
174
175         /* Having implementations for abstract methods are mandatory */
176         BUG_ON(!q->int_ops);
177
178         mutex_init(&q->vb_lock);
179         init_waitqueue_head(&q->wait);
180         INIT_LIST_HEAD(&q->stream);
181 }
182 EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
183
184 /* Locking: Only usage in bttv unsafe find way to remove */
185 int videobuf_queue_is_busy(struct videobuf_queue *q)
186 {
187         int i;
188
189         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
190
191         if (q->streaming) {
192                 dprintk(1, "busy: streaming active\n");
193                 return 1;
194         }
195         if (q->reading) {
196                 dprintk(1, "busy: pending read #1\n");
197                 return 1;
198         }
199         if (q->read_buf) {
200                 dprintk(1, "busy: pending read #2\n");
201                 return 1;
202         }
203         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
204                 if (NULL == q->bufs[i])
205                         continue;
206                 if (q->bufs[i]->map) {
207                         dprintk(1, "busy: buffer #%d mapped\n", i);
208                         return 1;
209                 }
210                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
211                         dprintk(1, "busy: buffer #%d queued\n", i);
212                         return 1;
213                 }
214                 if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
215                         dprintk(1, "busy: buffer #%d active\n", i);
216                         return 1;
217                 }
218         }
219         return 0;
220 }
221 EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
222
223 /*
224  * __videobuf_free() - free all the buffers and their control structures
225  *
226  * This function can only be called if streaming/reading is off, i.e. no buffers
227  * are under control of the driver.
228  */
229 /* Locking: Caller holds q->vb_lock */
230 static int __videobuf_free(struct videobuf_queue *q)
231 {
232         int i;
233
234         dprintk(1, "%s\n", __func__);
235         if (!q)
236                 return 0;
237
238         if (q->streaming || q->reading) {
239                 dprintk(1, "Cannot free buffers when streaming or reading\n");
240                 return -EBUSY;
241         }
242
243         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
244
245         for (i = 0; i < VIDEO_MAX_FRAME; i++)
246                 if (q->bufs[i] && q->bufs[i]->map) {
247                         dprintk(1, "Cannot free mmapped buffers\n");
248                         return -EBUSY;
249                 }
250
251         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
252                 if (NULL == q->bufs[i])
253                         continue;
254                 q->ops->buf_release(q, q->bufs[i]);
255                 kfree(q->bufs[i]);
256                 q->bufs[i] = NULL;
257         }
258
259         return 0;
260 }
261
262 /* Locking: Caller holds q->vb_lock */
263 void videobuf_queue_cancel(struct videobuf_queue *q)
264 {
265         unsigned long flags = 0;
266         int i;
267
268         q->streaming = 0;
269         q->reading  = 0;
270         wake_up_interruptible_sync(&q->wait);
271
272         /* remove queued buffers from list */
273         spin_lock_irqsave(q->irqlock, flags);
274         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
275                 if (NULL == q->bufs[i])
276                         continue;
277                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
278                         list_del(&q->bufs[i]->queue);
279                         q->bufs[i]->state = VIDEOBUF_ERROR;
280                         wake_up_all(&q->bufs[i]->done);
281                 }
282         }
283         spin_unlock_irqrestore(q->irqlock, flags);
284
285         /* free all buffers + clear queue */
286         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
287                 if (NULL == q->bufs[i])
288                         continue;
289                 q->ops->buf_release(q, q->bufs[i]);
290         }
291         INIT_LIST_HEAD(&q->stream);
292 }
293 EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
294
295 /* --------------------------------------------------------------------- */
296
297 /* Locking: Caller holds q->vb_lock */
298 enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
299 {
300         enum v4l2_field field = q->field;
301
302         BUG_ON(V4L2_FIELD_ANY == field);
303
304         if (V4L2_FIELD_ALTERNATE == field) {
305                 if (V4L2_FIELD_TOP == q->last) {
306                         field   = V4L2_FIELD_BOTTOM;
307                         q->last = V4L2_FIELD_BOTTOM;
308                 } else {
309                         field   = V4L2_FIELD_TOP;
310                         q->last = V4L2_FIELD_TOP;
311                 }
312         }
313         return field;
314 }
315 EXPORT_SYMBOL_GPL(videobuf_next_field);
316
317 /* Locking: Caller holds q->vb_lock */
318 static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
319                             struct videobuf_buffer *vb, enum v4l2_buf_type type)
320 {
321         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
322         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
323
324         b->index    = vb->i;
325         b->type     = type;
326
327         b->memory   = vb->memory;
328         switch (b->memory) {
329         case V4L2_MEMORY_MMAP:
330                 b->m.offset  = vb->boff;
331                 b->length    = vb->bsize;
332                 break;
333         case V4L2_MEMORY_USERPTR:
334                 b->m.userptr = vb->baddr;
335                 b->length    = vb->bsize;
336                 break;
337         case V4L2_MEMORY_OVERLAY:
338                 b->m.offset  = vb->boff;
339                 break;
340         case V4L2_MEMORY_DMABUF:
341                 /* DMABUF is not handled in videobuf framework */
342                 break;
343         }
344
345         b->flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
346         if (vb->map)
347                 b->flags |= V4L2_BUF_FLAG_MAPPED;
348
349         switch (vb->state) {
350         case VIDEOBUF_PREPARED:
351         case VIDEOBUF_QUEUED:
352         case VIDEOBUF_ACTIVE:
353                 b->flags |= V4L2_BUF_FLAG_QUEUED;
354                 break;
355         case VIDEOBUF_ERROR:
356                 b->flags |= V4L2_BUF_FLAG_ERROR;
357                 fallthrough;
358         case VIDEOBUF_DONE:
359                 b->flags |= V4L2_BUF_FLAG_DONE;
360                 break;
361         case VIDEOBUF_NEEDS_INIT:
362         case VIDEOBUF_IDLE:
363                 /* nothing */
364                 break;
365         }
366
367         b->field     = vb->field;
368         v4l2_buffer_set_timestamp(b, vb->ts);
369         b->bytesused = vb->size;
370         b->sequence  = vb->field_count >> 1;
371 }
372
373 int videobuf_mmap_free(struct videobuf_queue *q)
374 {
375         int ret;
376         videobuf_queue_lock(q);
377         ret = __videobuf_free(q);
378         videobuf_queue_unlock(q);
379         return ret;
380 }
381 EXPORT_SYMBOL_GPL(videobuf_mmap_free);
382
383 /* Locking: Caller holds q->vb_lock */
384 int __videobuf_mmap_setup(struct videobuf_queue *q,
385                         unsigned int bcount, unsigned int bsize,
386                         enum v4l2_memory memory)
387 {
388         unsigned int i;
389         int err;
390
391         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
392
393         err = __videobuf_free(q);
394         if (0 != err)
395                 return err;
396
397         /* Allocate and initialize buffers */
398         for (i = 0; i < bcount; i++) {
399                 q->bufs[i] = videobuf_alloc_vb(q);
400
401                 if (NULL == q->bufs[i])
402                         break;
403
404                 q->bufs[i]->i      = i;
405                 q->bufs[i]->memory = memory;
406                 q->bufs[i]->bsize  = bsize;
407                 switch (memory) {
408                 case V4L2_MEMORY_MMAP:
409                         q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
410                         break;
411                 case V4L2_MEMORY_USERPTR:
412                 case V4L2_MEMORY_OVERLAY:
413                 case V4L2_MEMORY_DMABUF:
414                         /* nothing */
415                         break;
416                 }
417         }
418
419         if (!i)
420                 return -ENOMEM;
421
422         dprintk(1, "mmap setup: %d buffers, %d bytes each\n", i, bsize);
423
424         return i;
425 }
426 EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
427
428 int videobuf_mmap_setup(struct videobuf_queue *q,
429                         unsigned int bcount, unsigned int bsize,
430                         enum v4l2_memory memory)
431 {
432         int ret;
433         videobuf_queue_lock(q);
434         ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
435         videobuf_queue_unlock(q);
436         return ret;
437 }
438 EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
439
440 int videobuf_reqbufs(struct videobuf_queue *q,
441                  struct v4l2_requestbuffers *req)
442 {
443         unsigned int size, count;
444         int retval;
445
446         if (req->memory != V4L2_MEMORY_MMAP     &&
447             req->memory != V4L2_MEMORY_USERPTR  &&
448             req->memory != V4L2_MEMORY_OVERLAY) {
449                 dprintk(1, "reqbufs: memory type invalid\n");
450                 return -EINVAL;
451         }
452
453         videobuf_queue_lock(q);
454         if (req->type != q->type) {
455                 dprintk(1, "reqbufs: queue type invalid\n");
456                 retval = -EINVAL;
457                 goto done;
458         }
459
460         if (q->streaming) {
461                 dprintk(1, "reqbufs: streaming already exists\n");
462                 retval = -EBUSY;
463                 goto done;
464         }
465         if (!list_empty(&q->stream)) {
466                 dprintk(1, "reqbufs: stream running\n");
467                 retval = -EBUSY;
468                 goto done;
469         }
470
471         if (req->count == 0) {
472                 dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
473                 retval = __videobuf_free(q);
474                 goto done;
475         }
476
477         count = req->count;
478         if (count > VIDEO_MAX_FRAME)
479                 count = VIDEO_MAX_FRAME;
480         size = 0;
481         q->ops->buf_setup(q, &count, &size);
482         dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
483                 count, size,
484                 (unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
485
486         retval = __videobuf_mmap_setup(q, count, size, req->memory);
487         if (retval < 0) {
488                 dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
489                 goto done;
490         }
491
492         req->count = retval;
493         retval = 0;
494
495  done:
496         videobuf_queue_unlock(q);
497         return retval;
498 }
499 EXPORT_SYMBOL_GPL(videobuf_reqbufs);
500
501 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
502 {
503         int ret = -EINVAL;
504
505         videobuf_queue_lock(q);
506         if (unlikely(b->type != q->type)) {
507                 dprintk(1, "querybuf: Wrong type.\n");
508                 goto done;
509         }
510         if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
511                 dprintk(1, "querybuf: index out of range.\n");
512                 goto done;
513         }
514         if (unlikely(NULL == q->bufs[b->index])) {
515                 dprintk(1, "querybuf: buffer is null.\n");
516                 goto done;
517         }
518
519         videobuf_status(q, b, q->bufs[b->index], q->type);
520
521         ret = 0;
522 done:
523         videobuf_queue_unlock(q);
524         return ret;
525 }
526 EXPORT_SYMBOL_GPL(videobuf_querybuf);
527
528 int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
529 {
530         struct videobuf_buffer *buf;
531         enum v4l2_field field;
532         unsigned long flags = 0;
533         int retval;
534
535         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
536
537         if (b->memory == V4L2_MEMORY_MMAP)
538                 mmap_read_lock(current->mm);
539
540         videobuf_queue_lock(q);
541         retval = -EBUSY;
542         if (q->reading) {
543                 dprintk(1, "qbuf: Reading running...\n");
544                 goto done;
545         }
546         retval = -EINVAL;
547         if (b->type != q->type) {
548                 dprintk(1, "qbuf: Wrong type.\n");
549                 goto done;
550         }
551         if (b->index >= VIDEO_MAX_FRAME) {
552                 dprintk(1, "qbuf: index out of range.\n");
553                 goto done;
554         }
555         buf = q->bufs[b->index];
556         if (NULL == buf) {
557                 dprintk(1, "qbuf: buffer is null.\n");
558                 goto done;
559         }
560         MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
561         if (buf->memory != b->memory) {
562                 dprintk(1, "qbuf: memory type is wrong.\n");
563                 goto done;
564         }
565         if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
566                 dprintk(1, "qbuf: buffer is already queued or active.\n");
567                 goto done;
568         }
569
570         switch (b->memory) {
571         case V4L2_MEMORY_MMAP:
572                 if (0 == buf->baddr) {
573                         dprintk(1, "qbuf: mmap requested but buffer addr is zero!\n");
574                         goto done;
575                 }
576                 if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
577                     || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
578                     || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT
579                     || q->type == V4L2_BUF_TYPE_SDR_OUTPUT) {
580                         buf->size = b->bytesused;
581                         buf->field = b->field;
582                         buf->ts = v4l2_buffer_get_timestamp(b);
583                 }
584                 break;
585         case V4L2_MEMORY_USERPTR:
586                 if (b->length < buf->bsize) {
587                         dprintk(1, "qbuf: buffer length is not enough\n");
588                         goto done;
589                 }
590                 if (VIDEOBUF_NEEDS_INIT != buf->state &&
591                     buf->baddr != b->m.userptr)
592                         q->ops->buf_release(q, buf);
593                 buf->baddr = b->m.userptr;
594                 break;
595         case V4L2_MEMORY_OVERLAY:
596                 buf->boff = b->m.offset;
597                 break;
598         default:
599                 dprintk(1, "qbuf: wrong memory type\n");
600                 goto done;
601         }
602
603         dprintk(1, "qbuf: requesting next field\n");
604         field = videobuf_next_field(q);
605         retval = q->ops->buf_prepare(q, buf, field);
606         if (0 != retval) {
607                 dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
608                 goto done;
609         }
610
611         list_add_tail(&buf->stream, &q->stream);
612         if (q->streaming) {
613                 spin_lock_irqsave(q->irqlock, flags);
614                 q->ops->buf_queue(q, buf);
615                 spin_unlock_irqrestore(q->irqlock, flags);
616         }
617         dprintk(1, "qbuf: succeeded\n");
618         retval = 0;
619         wake_up_interruptible_sync(&q->wait);
620
621 done:
622         videobuf_queue_unlock(q);
623
624         if (b->memory == V4L2_MEMORY_MMAP)
625                 mmap_read_unlock(current->mm);
626
627         return retval;
628 }
629 EXPORT_SYMBOL_GPL(videobuf_qbuf);
630
631 /* Locking: Caller holds q->vb_lock */
632 static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
633 {
634         int retval;
635
636 checks:
637         if (!q->streaming) {
638                 dprintk(1, "next_buffer: Not streaming\n");
639                 retval = -EINVAL;
640                 goto done;
641         }
642
643         if (list_empty(&q->stream)) {
644                 if (noblock) {
645                         retval = -EAGAIN;
646                         dprintk(2, "next_buffer: no buffers to dequeue\n");
647                         goto done;
648                 } else {
649                         dprintk(2, "next_buffer: waiting on buffer\n");
650
651                         /* Drop lock to avoid deadlock with qbuf */
652                         videobuf_queue_unlock(q);
653
654                         /* Checking list_empty and streaming is safe without
655                          * locks because we goto checks to validate while
656                          * holding locks before proceeding */
657                         retval = wait_event_interruptible(q->wait,
658                                 !list_empty(&q->stream) || !q->streaming);
659                         videobuf_queue_lock(q);
660
661                         if (retval)
662                                 goto done;
663
664                         goto checks;
665                 }
666         }
667
668         retval = 0;
669
670 done:
671         return retval;
672 }
673
674 /* Locking: Caller holds q->vb_lock */
675 static int stream_next_buffer(struct videobuf_queue *q,
676                         struct videobuf_buffer **vb, int nonblocking)
677 {
678         int retval;
679         struct videobuf_buffer *buf = NULL;
680
681         retval = stream_next_buffer_check_queue(q, nonblocking);
682         if (retval)
683                 goto done;
684
685         buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
686         retval = videobuf_waiton(q, buf, nonblocking, 1);
687         if (retval < 0)
688                 goto done;
689
690         *vb = buf;
691 done:
692         return retval;
693 }
694
695 int videobuf_dqbuf(struct videobuf_queue *q,
696                    struct v4l2_buffer *b, int nonblocking)
697 {
698         struct videobuf_buffer *buf = NULL;
699         int retval;
700
701         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
702
703         memset(b, 0, sizeof(*b));
704         videobuf_queue_lock(q);
705
706         retval = stream_next_buffer(q, &buf, nonblocking);
707         if (retval < 0) {
708                 dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
709                 goto done;
710         }
711
712         switch (buf->state) {
713         case VIDEOBUF_ERROR:
714                 dprintk(1, "dqbuf: state is error\n");
715                 break;
716         case VIDEOBUF_DONE:
717                 dprintk(1, "dqbuf: state is done\n");
718                 break;
719         default:
720                 dprintk(1, "dqbuf: state invalid\n");
721                 retval = -EINVAL;
722                 goto done;
723         }
724         CALL(q, sync, q, buf);
725         videobuf_status(q, b, buf, q->type);
726         list_del(&buf->stream);
727         buf->state = VIDEOBUF_IDLE;
728         b->flags &= ~V4L2_BUF_FLAG_DONE;
729 done:
730         videobuf_queue_unlock(q);
731         return retval;
732 }
733 EXPORT_SYMBOL_GPL(videobuf_dqbuf);
734
735 int videobuf_streamon(struct videobuf_queue *q)
736 {
737         struct videobuf_buffer *buf;
738         unsigned long flags = 0;
739         int retval;
740
741         videobuf_queue_lock(q);
742         retval = -EBUSY;
743         if (q->reading)
744                 goto done;
745         retval = 0;
746         if (q->streaming)
747                 goto done;
748         q->streaming = 1;
749         spin_lock_irqsave(q->irqlock, flags);
750         list_for_each_entry(buf, &q->stream, stream)
751                 if (buf->state == VIDEOBUF_PREPARED)
752                         q->ops->buf_queue(q, buf);
753         spin_unlock_irqrestore(q->irqlock, flags);
754
755         wake_up_interruptible_sync(&q->wait);
756 done:
757         videobuf_queue_unlock(q);
758         return retval;
759 }
760 EXPORT_SYMBOL_GPL(videobuf_streamon);
761
762 /* Locking: Caller holds q->vb_lock */
763 static int __videobuf_streamoff(struct videobuf_queue *q)
764 {
765         if (!q->streaming)
766                 return -EINVAL;
767
768         videobuf_queue_cancel(q);
769
770         return 0;
771 }
772
773 int videobuf_streamoff(struct videobuf_queue *q)
774 {
775         int retval;
776
777         videobuf_queue_lock(q);
778         retval = __videobuf_streamoff(q);
779         videobuf_queue_unlock(q);
780
781         return retval;
782 }
783 EXPORT_SYMBOL_GPL(videobuf_streamoff);
784
785 /* Locking: Caller holds q->vb_lock */
786 static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
787                                       char __user *data,
788                                       size_t count, loff_t *ppos)
789 {
790         enum v4l2_field field;
791         unsigned long flags = 0;
792         int retval;
793
794         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
795
796         /* setup stuff */
797         q->read_buf = videobuf_alloc_vb(q);
798         if (NULL == q->read_buf)
799                 return -ENOMEM;
800
801         q->read_buf->memory = V4L2_MEMORY_USERPTR;
802         q->read_buf->baddr  = (unsigned long)data;
803         q->read_buf->bsize  = count;
804
805         field = videobuf_next_field(q);
806         retval = q->ops->buf_prepare(q, q->read_buf, field);
807         if (0 != retval)
808                 goto done;
809
810         /* start capture & wait */
811         spin_lock_irqsave(q->irqlock, flags);
812         q->ops->buf_queue(q, q->read_buf);
813         spin_unlock_irqrestore(q->irqlock, flags);
814         retval = videobuf_waiton(q, q->read_buf, 0, 0);
815         if (0 == retval) {
816                 CALL(q, sync, q, q->read_buf);
817                 if (VIDEOBUF_ERROR == q->read_buf->state)
818                         retval = -EIO;
819                 else
820                         retval = q->read_buf->size;
821         }
822
823 done:
824         /* cleanup */
825         q->ops->buf_release(q, q->read_buf);
826         kfree(q->read_buf);
827         q->read_buf = NULL;
828         return retval;
829 }
830
831 static int __videobuf_copy_to_user(struct videobuf_queue *q,
832                                    struct videobuf_buffer *buf,
833                                    char __user *data, size_t count,
834                                    int nonblocking)
835 {
836         void *vaddr = CALLPTR(q, vaddr, buf);
837
838         /* copy to userspace */
839         if (count > buf->size - q->read_off)
840                 count = buf->size - q->read_off;
841
842         if (copy_to_user(data, vaddr + q->read_off, count))
843                 return -EFAULT;
844
845         return count;
846 }
847
848 static int __videobuf_copy_stream(struct videobuf_queue *q,
849                                   struct videobuf_buffer *buf,
850                                   char __user *data, size_t count, size_t pos,
851                                   int vbihack, int nonblocking)
852 {
853         unsigned int *fc = CALLPTR(q, vaddr, buf);
854
855         if (vbihack) {
856                 /* dirty, undocumented hack -- pass the frame counter
857                         * within the last four bytes of each vbi data block.
858                         * We need that one to maintain backward compatibility
859                         * to all vbi decoding software out there ... */
860                 fc += (buf->size >> 2) - 1;
861                 *fc = buf->field_count >> 1;
862                 dprintk(1, "vbihack: %d\n", *fc);
863         }
864
865         /* copy stuff using the common method */
866         count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
867
868         if ((count == -EFAULT) && (pos == 0))
869                 return -EFAULT;
870
871         return count;
872 }
873
874 ssize_t videobuf_read_one(struct videobuf_queue *q,
875                           char __user *data, size_t count, loff_t *ppos,
876                           int nonblocking)
877 {
878         enum v4l2_field field;
879         unsigned long flags = 0;
880         unsigned size = 0, nbufs = 1;
881         int retval;
882
883         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
884
885         videobuf_queue_lock(q);
886
887         q->ops->buf_setup(q, &nbufs, &size);
888
889         if (NULL == q->read_buf  &&
890             count >= size        &&
891             !nonblocking) {
892                 retval = videobuf_read_zerocopy(q, data, count, ppos);
893                 if (retval >= 0  ||  retval == -EIO)
894                         /* ok, all done */
895                         goto done;
896                 /* fallback to kernel bounce buffer on failures */
897         }
898
899         if (NULL == q->read_buf) {
900                 /* need to capture a new frame */
901                 retval = -ENOMEM;
902                 q->read_buf = videobuf_alloc_vb(q);
903
904                 dprintk(1, "video alloc=0x%p\n", q->read_buf);
905                 if (NULL == q->read_buf)
906                         goto done;
907                 q->read_buf->memory = V4L2_MEMORY_USERPTR;
908                 q->read_buf->bsize = count; /* preferred size */
909                 field = videobuf_next_field(q);
910                 retval = q->ops->buf_prepare(q, q->read_buf, field);
911
912                 if (0 != retval) {
913                         kfree(q->read_buf);
914                         q->read_buf = NULL;
915                         goto done;
916                 }
917
918                 spin_lock_irqsave(q->irqlock, flags);
919                 q->ops->buf_queue(q, q->read_buf);
920                 spin_unlock_irqrestore(q->irqlock, flags);
921
922                 q->read_off = 0;
923         }
924
925         /* wait until capture is done */
926         retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
927         if (0 != retval)
928                 goto done;
929
930         CALL(q, sync, q, q->read_buf);
931
932         if (VIDEOBUF_ERROR == q->read_buf->state) {
933                 /* catch I/O errors */
934                 q->ops->buf_release(q, q->read_buf);
935                 kfree(q->read_buf);
936                 q->read_buf = NULL;
937                 retval = -EIO;
938                 goto done;
939         }
940
941         /* Copy to userspace */
942         retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
943         if (retval < 0)
944                 goto done;
945
946         q->read_off += retval;
947         if (q->read_off == q->read_buf->size) {
948                 /* all data copied, cleanup */
949                 q->ops->buf_release(q, q->read_buf);
950                 kfree(q->read_buf);
951                 q->read_buf = NULL;
952         }
953
954 done:
955         videobuf_queue_unlock(q);
956         return retval;
957 }
958 EXPORT_SYMBOL_GPL(videobuf_read_one);
959
960 /* Locking: Caller holds q->vb_lock */
961 static int __videobuf_read_start(struct videobuf_queue *q)
962 {
963         enum v4l2_field field;
964         unsigned long flags = 0;
965         unsigned int count = 0, size = 0;
966         int err, i;
967
968         q->ops->buf_setup(q, &count, &size);
969         if (count < 2)
970                 count = 2;
971         if (count > VIDEO_MAX_FRAME)
972                 count = VIDEO_MAX_FRAME;
973         size = PAGE_ALIGN(size);
974
975         err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
976         if (err < 0)
977                 return err;
978
979         count = err;
980
981         for (i = 0; i < count; i++) {
982                 field = videobuf_next_field(q);
983                 err = q->ops->buf_prepare(q, q->bufs[i], field);
984                 if (err)
985                         return err;
986                 list_add_tail(&q->bufs[i]->stream, &q->stream);
987         }
988         spin_lock_irqsave(q->irqlock, flags);
989         for (i = 0; i < count; i++)
990                 q->ops->buf_queue(q, q->bufs[i]);
991         spin_unlock_irqrestore(q->irqlock, flags);
992         q->reading = 1;
993         return 0;
994 }
995
996 static void __videobuf_read_stop(struct videobuf_queue *q)
997 {
998         int i;
999
1000         videobuf_queue_cancel(q);
1001         __videobuf_free(q);
1002         INIT_LIST_HEAD(&q->stream);
1003         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1004                 if (NULL == q->bufs[i])
1005                         continue;
1006                 kfree(q->bufs[i]);
1007                 q->bufs[i] = NULL;
1008         }
1009         q->read_buf = NULL;
1010 }
1011
1012 int videobuf_read_start(struct videobuf_queue *q)
1013 {
1014         int rc;
1015
1016         videobuf_queue_lock(q);
1017         rc = __videobuf_read_start(q);
1018         videobuf_queue_unlock(q);
1019
1020         return rc;
1021 }
1022 EXPORT_SYMBOL_GPL(videobuf_read_start);
1023
1024 void videobuf_read_stop(struct videobuf_queue *q)
1025 {
1026         videobuf_queue_lock(q);
1027         __videobuf_read_stop(q);
1028         videobuf_queue_unlock(q);
1029 }
1030 EXPORT_SYMBOL_GPL(videobuf_read_stop);
1031
1032 void videobuf_stop(struct videobuf_queue *q)
1033 {
1034         videobuf_queue_lock(q);
1035
1036         if (q->streaming)
1037                 __videobuf_streamoff(q);
1038
1039         if (q->reading)
1040                 __videobuf_read_stop(q);
1041
1042         videobuf_queue_unlock(q);
1043 }
1044 EXPORT_SYMBOL_GPL(videobuf_stop);
1045
1046 ssize_t videobuf_read_stream(struct videobuf_queue *q,
1047                              char __user *data, size_t count, loff_t *ppos,
1048                              int vbihack, int nonblocking)
1049 {
1050         int rc, retval;
1051         unsigned long flags = 0;
1052
1053         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1054
1055         dprintk(2, "%s\n", __func__);
1056         videobuf_queue_lock(q);
1057         retval = -EBUSY;
1058         if (q->streaming)
1059                 goto done;
1060         if (!q->reading) {
1061                 retval = __videobuf_read_start(q);
1062                 if (retval < 0)
1063                         goto done;
1064         }
1065
1066         retval = 0;
1067         while (count > 0) {
1068                 /* get / wait for data */
1069                 if (NULL == q->read_buf) {
1070                         q->read_buf = list_entry(q->stream.next,
1071                                                  struct videobuf_buffer,
1072                                                  stream);
1073                         list_del(&q->read_buf->stream);
1074                         q->read_off = 0;
1075                 }
1076                 rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
1077                 if (rc < 0) {
1078                         if (0 == retval)
1079                                 retval = rc;
1080                         break;
1081                 }
1082
1083                 if (q->read_buf->state == VIDEOBUF_DONE) {
1084                         rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
1085                                         retval, vbihack, nonblocking);
1086                         if (rc < 0) {
1087                                 retval = rc;
1088                                 break;
1089                         }
1090                         retval      += rc;
1091                         count       -= rc;
1092                         q->read_off += rc;
1093                 } else {
1094                         /* some error */
1095                         q->read_off = q->read_buf->size;
1096                         if (0 == retval)
1097                                 retval = -EIO;
1098                 }
1099
1100                 /* requeue buffer when done with copying */
1101                 if (q->read_off == q->read_buf->size) {
1102                         list_add_tail(&q->read_buf->stream,
1103                                       &q->stream);
1104                         spin_lock_irqsave(q->irqlock, flags);
1105                         q->ops->buf_queue(q, q->read_buf);
1106                         spin_unlock_irqrestore(q->irqlock, flags);
1107                         q->read_buf = NULL;
1108                 }
1109                 if (retval < 0)
1110                         break;
1111         }
1112
1113 done:
1114         videobuf_queue_unlock(q);
1115         return retval;
1116 }
1117 EXPORT_SYMBOL_GPL(videobuf_read_stream);
1118
1119 __poll_t videobuf_poll_stream(struct file *file,
1120                               struct videobuf_queue *q,
1121                               poll_table *wait)
1122 {
1123         __poll_t req_events = poll_requested_events(wait);
1124         struct videobuf_buffer *buf = NULL;
1125         __poll_t rc = 0;
1126
1127         videobuf_queue_lock(q);
1128         if (q->streaming) {
1129                 if (!list_empty(&q->stream))
1130                         buf = list_entry(q->stream.next,
1131                                          struct videobuf_buffer, stream);
1132         } else if (req_events & (EPOLLIN | EPOLLRDNORM)) {
1133                 if (!q->reading)
1134                         __videobuf_read_start(q);
1135                 if (!q->reading) {
1136                         rc = EPOLLERR;
1137                 } else if (NULL == q->read_buf) {
1138                         q->read_buf = list_entry(q->stream.next,
1139                                                  struct videobuf_buffer,
1140                                                  stream);
1141                         list_del(&q->read_buf->stream);
1142                         q->read_off = 0;
1143                 }
1144                 buf = q->read_buf;
1145         }
1146         if (buf)
1147                 poll_wait(file, &buf->done, wait);
1148         else
1149                 rc = EPOLLERR;
1150
1151         if (0 == rc) {
1152                 if (buf->state == VIDEOBUF_DONE ||
1153                     buf->state == VIDEOBUF_ERROR) {
1154                         switch (q->type) {
1155                         case V4L2_BUF_TYPE_VIDEO_OUTPUT:
1156                         case V4L2_BUF_TYPE_VBI_OUTPUT:
1157                         case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
1158                         case V4L2_BUF_TYPE_SDR_OUTPUT:
1159                                 rc = EPOLLOUT | EPOLLWRNORM;
1160                                 break;
1161                         default:
1162                                 rc = EPOLLIN | EPOLLRDNORM;
1163                                 break;
1164                         }
1165                 }
1166         }
1167         videobuf_queue_unlock(q);
1168         return rc;
1169 }
1170 EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1171
1172 int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma)
1173 {
1174         int rc = -EINVAL;
1175         int i;
1176
1177         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1178
1179         if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) {
1180                 dprintk(1, "mmap appl bug: PROT_WRITE and MAP_SHARED are required\n");
1181                 return -EINVAL;
1182         }
1183
1184         videobuf_queue_lock(q);
1185         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1186                 struct videobuf_buffer *buf = q->bufs[i];
1187
1188                 if (buf && buf->memory == V4L2_MEMORY_MMAP &&
1189                                 buf->boff == (vma->vm_pgoff << PAGE_SHIFT)) {
1190                         rc = CALL(q, mmap_mapper, q, buf, vma);
1191                         break;
1192                 }
1193         }
1194         videobuf_queue_unlock(q);
1195
1196         return rc;
1197 }
1198 EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);