aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/video/cx231xx/cx231xx-vbi.c
blob: 82db39d339e10552df36c8ab867091c2b135f23b (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
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
/*
   cx231xx_vbi.c - driver for Conexant Cx23100/101/102 USB video capture devices

   Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
	Based on cx88 driver

   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.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bitmap.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include <linux/version.h>
#include <linux/mm.h>
#include <linux/mutex.h>

#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-chip-ident.h>
#include <media/msp3400.h>
#include <media/tuner.h>

#include "cx231xx.h"
#include "cx231xx-vbi.h"

static inline void print_err_status(struct cx231xx *dev, int packet, int status)
{
	char *errmsg = "Unknown";

	switch (status) {
	case -ENOENT:
		errmsg = "unlinked synchronuously";
		break;
	case -ECONNRESET:
		errmsg = "unlinked asynchronuously";
		break;
	case -ENOSR:
		errmsg = "Buffer error (overrun)";
		break;
	case -EPIPE:
		errmsg = "Stalled (device not responding)";
		break;
	case -EOVERFLOW:
		errmsg = "Babble (bad cable?)";
		break;
	case -EPROTO:
		errmsg = "Bit-stuff error (bad cable?)";
		break;
	case -EILSEQ:
		errmsg = "CRC/Timeout (could be anything)";
		break;
	case -ETIME:
		errmsg = "Device does not respond";
		break;
	}
	if (packet < 0) {
		cx231xx_err(DRIVER_NAME "URB status %d [%s].\n", status,
			    errmsg);
	} else {
		cx231xx_err(DRIVER_NAME "URB packet %d, status %d [%s].\n",
			    packet, status, errmsg);
	}
}

/*
 * Controls the isoc copy of each urb packet
 */
static inline int cx231xx_isoc_vbi_copy(struct cx231xx *dev, struct urb *urb)
{
	struct cx231xx_buffer *buf;
	struct cx231xx_dmaqueue *dma_q = urb->context;
	int rc = 1;
	unsigned char *p_buffer;
	u32 bytes_parsed = 0, buffer_size = 0;
	u8 sav_eav = 0;

	if (!dev)
		return 0;

	if ((dev->state & DEV_DISCONNECTED) || (dev->state & DEV_MISCONFIGURED))
		return 0;

	if (urb->status < 0) {
		print_err_status(dev, -1, urb->status);
		if (urb->status == -ENOENT)
			return 0;
	}

	buf = dev->vbi_mode.isoc_ctl.buf;

	/* get buffer pointer and length */
	p_buffer = urb->transfer_buffer;
	buffer_size = urb->actual_length;

	if (buffer_size > 0) {
		bytes_parsed = 0;

		if (dma_q->is_partial_line) {
			/* Handle the case where we were working on a partial
			   line */
			sav_eav = dma_q->last_sav;
		} else {
			/* Check for a SAV/EAV overlapping the
			   buffer boundary */

			sav_eav = cx231xx_find_boundary_SAV_EAV(p_buffer,
							  dma_q->partial_buf,
							  &bytes_parsed);
		}

		sav_eav &= 0xF0;
		/* Get the first line if we have some portion of an SAV/EAV from
		   the last buffer or a partial line */
		if (sav_eav) {
			bytes_parsed += cx231xx_get_vbi_line(dev, dma_q,
				sav_eav,		       /* SAV/EAV */
				p_buffer + bytes_parsed,       /* p_buffer */
				buffer_size - bytes_parsed);   /* buffer size */
		}

		/* Now parse data that is completely in this buffer */
		dma_q->is_partial_line = 0;

		while (bytes_parsed < buffer_size) {
			u32 bytes_used = 0;

			sav_eav = cx231xx_find_next_SAV_EAV(
				p_buffer + bytes_parsed,	/* p_buffer */
				buffer_size - bytes_parsed, /* buffer size */
				&bytes_used);	/* bytes used to get SAV/EAV */

			bytes_parsed += bytes_used;

			sav_eav &= 0xF0;
			if (sav_eav && (bytes_parsed < buffer_size)) {
				bytes_parsed += cx231xx_get_vbi_line(dev,
					dma_q, sav_eav,	/* SAV/EAV */
					p_buffer+bytes_parsed, /* p_buffer */
					buffer_size-bytes_parsed);/*buf size*/
			}
		}

		/* Save the last four bytes of the buffer so we can
		check the buffer boundary condition next time */
		memcpy(dma_q->partial_buf, p_buffer + buffer_size - 4, 4);
		bytes_parsed = 0;
	}

	return rc;
}

/* ------------------------------------------------------------------
	Vbi buf operations
   ------------------------------------------------------------------*/

static int
vbi_buffer_setup(struct videobuf_queue *vq, unsigned int *count,
		 unsigned int *size)
{
	struct cx231xx_fh *fh = vq->priv_data;
	struct cx231xx *dev = fh->dev;
	u32 height = 0;

	height = ((dev->norm & V4L2_STD_625_50) ?
		  PAL_VBI_LINES : NTSC_VBI_LINES);

	*size = (dev->width * height * 2);
	if (0 == *count)
		*count = CX231XX_DEF_VBI_BUF;

	if (*count < CX231XX_MIN_BUF)
		*count = CX231XX_MIN_BUF;

	/* call VBI setup if required */
	/* cx231xx_i2c_call_clients(&dev->i2c_bus[1], VIDIOC_S_FREQUENCY, &f);
	 */

	return 0;
}

/* This is called *without* dev->slock held; please keep it that way */
static void free_buffer(struct videobuf_queue *vq, struct cx231xx_buffer *buf)
{
	struct cx231xx_fh *fh = vq->priv_data;
	struct cx231xx *dev = fh->dev;
	unsigned long flags = 0;
	if (in_interrupt())
		BUG();

	/* We used to wait for the buffer to finish here, but this didn't work
	   because, as we were keeping the state as VIDEOBUF_QUEUED,
	   videobuf_queue_cancel marked it as finished for us.
	   (Also, it could wedge forever if the hardware was misconfigured.)

	   This should be safe; by the time we get here, the buffer isn't
	   queued anymore. If we ever start marking the buffers as
	   VIDEOBUF_ACTIVE, it won't be, though.
	 */
	spin_lock_irqsave(&dev->vbi_mode.slock, flags);
	if (dev->vbi_mode.isoc_ctl.buf == buf)
		dev->vbi_mode.isoc_ctl.buf = NULL;
	spin_unlock_irqrestore(&dev->vbi_mode.slock, flags);

	videobuf_vmalloc_free(&buf->vb);
	buf->vb.state = VIDEOBUF_NEEDS_INIT;
}

static int
vbi_buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
		   enum v4l2_field field)
{
	struct cx231xx_fh *fh = vq->priv_data;
	struct cx231xx_buffer *buf =
	    container_of(vb, struct cx231xx_buffer, vb);
	struct cx231xx *dev = fh->dev;
	int rc = 0, urb_init = 0;
	u32 height = 0;

	height = ((dev->norm & V4L2_STD_625_50) ?
		  PAL_VBI_LINES : NTSC_VBI_LINES);
	buf->vb.size = ((dev->width << 1) * height);

	if (0 != buf->vb.baddr && buf->vb.bsize < buf->vb.size)
		return -EINVAL;

	buf->vb.width = dev->width;
	buf->vb.height = height;
	buf->vb.field = field;
	buf->vb.field = V4L2_FIELD_SEQ_TB;

	if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
		rc = videobuf_iolock(vq, &buf->vb, NULL);
		if (rc < 0)
			goto fail;
	}

	if (!dev->vbi_mode.isoc_ctl.num_bufs)
		urb_init = 1;

	if (urb_init) {
		rc = cx231xx_init_vbi_isoc(dev, CX231XX_NUM_VBI_PACKETS,
					   CX231XX_NUM_VBI_BUFS,
					   dev->vbi_mode.alt_max_pkt_size[0],
					   cx231xx_isoc_vbi_copy);
		if (rc < 0)
			goto fail;
	}

	buf->vb.state = VIDEOBUF_PREPARED;
	return 0;

fail:
	free_buffer(vq, buf);
	return rc;
}

static void
vbi_buffer_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
{
	struct cx231xx_buffer *buf =
	    container_of(vb, struct cx231xx_buffer, vb);
	struct cx231xx_fh *fh = vq->priv_data;
	struct cx231xx *dev = fh->dev;
	struct cx231xx_dmaqueue *vidq = &dev->vbi_mode.vidq;

	buf->vb.state = VIDEOBUF_QUEUED;
	list_add_tail(&buf->vb.queue, &vidq->active);

}

static void vbi_buffer_release(struct videobuf_queue *vq,
			       struct videobuf_buffer *vb)
{
	struct cx231xx_buffer *buf =
	    container_of(vb, struct cx231xx_buffer, vb);


	free_buffer(vq, buf);
}

struct videobuf_queue_ops cx231xx_vbi_qops = {
	.buf_setup   = vbi_buffer_setup,
	.buf_prepare = vbi_buffer_prepare,
	.buf_queue   = vbi_buffer_queue,
	.buf_release = vbi_buffer_release,
};

/* ------------------------------------------------------------------
	URB control
   ------------------------------------------------------------------*/

/*
 * IRQ callback, called by URB callback
 */
static void cx231xx_irq_vbi_callback(struct urb *urb)
{
	struct cx231xx_dmaqueue *dma_q = urb->context;
	struct cx231xx_video_mode *vmode =
	    container_of(dma_q, struct cx231xx_video_mode, vidq);
	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
	int rc;

	switch (urb->status) {
	case 0:		/* success */
	case -ETIMEDOUT:	/* NAK */
		break;
	case -ECONNRESET:	/* kill */
	case -ENOENT:
	case -ESHUTDOWN:
		return;
	default:		/* error */
		cx231xx_err(DRIVER_NAME "urb completition error %d.\n",
			    urb->status);
		break;
	}

	/* Copy data from URB */
	spin_lock(&dev->vbi_mode.slock);
	rc = dev->vbi_mode.isoc_ctl.isoc_copy(dev, urb);
	spin_unlock(&dev->vbi_mode.slock);

	/* Reset status */
	urb->status = 0;

	urb->status = usb_submit_urb(urb, GFP_ATOMIC);
	if (urb->status) {
		cx231xx_err(DRIVER_NAME "urb resubmit failed (error=%i)\n",
			    urb->status);
	}
}

/*
 * Stop and Deallocate URBs
 */
void cx231xx_uninit_vbi_isoc(struct cx231xx *dev)
{
	struct urb *urb;
	int i;

	cx231xx_info(DRIVER_NAME "cx231xx: called cx231xx_uninit_vbi_isoc\n");

	dev->vbi_mode.isoc_ctl.nfields = -1;
	for (i = 0; i < dev->vbi_mode.isoc_ctl.num_bufs; i++) {
		urb = dev->vbi_mode.isoc_ctl.urb[i];
		if (urb) {
			if (!irqs_disabled())
				usb_kill_urb(urb);
			else
				usb_unlink_urb(urb);

			if (dev->vbi_mode.isoc_ctl.transfer_buffer[i]) {

				kfree(dev->vbi_mode.isoc_ctl.
				      transfer_buffer[i]);
				dev->vbi_mode.isoc_ctl.transfer_buffer[i] =
				    NULL;
			}
			usb_free_urb(urb);
			dev->vbi_mode.isoc_ctl.urb[i] = NULL;
		}
		dev->vbi_mode.isoc_ctl.transfer_buffer[i] = NULL;
	}

	kfree(dev->vbi_mode.isoc_ctl.urb);
	kfree(dev->vbi_mode.isoc_ctl.transfer_buffer);

	dev->vbi_mode.isoc_ctl.urb = NULL;
	dev->vbi_mode.isoc_ctl.transfer_buffer = NULL;
	dev->vbi_mode.isoc_ctl.num_bufs = 0;

	cx231xx_capture_start(dev, 0, Vbi);
}
EXPORT_SYMBOL_GPL(cx231xx_uninit_vbi_isoc);

/*
 * Allocate URBs and start IRQ
 */
int cx231xx_init_vbi_isoc(struct cx231xx *dev, int max_packets,
			  int num_bufs, int max_pkt_size,
			  int (*isoc_copy) (struct cx231xx *dev,
					    struct urb *urb))
{
	struct cx231xx_dmaqueue *dma_q = &dev->vbi_mode.vidq;
	int i;
	int sb_size, pipe;
	struct urb *urb;
	int rc;

	cx231xx_info(DRIVER_NAME "cx231xx: called cx231xx_prepare_isoc\n");

	/* De-allocates all pending stuff */
	cx231xx_uninit_vbi_isoc(dev);

	/* clear if any halt */
	usb_clear_halt(dev->udev,
		       usb_rcvbulkpipe(dev->udev,
				       dev->vbi_mode.end_point_addr));

	dev->vbi_mode.isoc_ctl.isoc_copy = isoc_copy;
	dev->vbi_mode.isoc_ctl.num_bufs = num_bufs;
	dma_q->pos = 0;
	dma_q->is_partial_line = 0;
	dma_q->last_sav = 0;
	dma_q->current_field = -1;
	dma_q->bytes_left_in_line = dev->width << 1;
	dma_q->lines_per_field = ((dev->norm & V4L2_STD_625_50) ?
				  PAL_VBI_LINES : NTSC_VBI_LINES);
	dma_q->lines_completed = 0;
	for (i = 0; i < 8; i++)
		dma_q->partial_buf[i] = 0;

	dev->vbi_mode.isoc_ctl.urb = kzalloc(sizeof(void *) * num_bufs,
					     GFP_KERNEL);
	if (!dev->vbi_mode.isoc_ctl.urb) {
		cx231xx_errdev("cannot alloc memory for usb buffers\n");
		return -ENOMEM;
	}

	dev->vbi_mode.isoc_ctl.transfer_buffer =
	    kzalloc(sizeof(void *) * num_bufs, GFP_KERNEL);
	if (!dev->vbi_mode.isoc_ctl.transfer_buffer) {
		cx231xx_errdev("cannot allocate memory for usbtransfer\n");
		kfree(dev->vbi_mode.isoc_ctl.urb);
		return -ENOMEM;
	}

	dev->vbi_mode.isoc_ctl.max_pkt_size = max_pkt_size;
	dev->vbi_mode.isoc_ctl.buf = NULL;

	sb_size = max_packets * dev->vbi_mode.isoc_ctl.max_pkt_size;

	/* allocate urbs and transfer buffers */
	for (i = 0; i < dev->vbi_mode.isoc_ctl.num_bufs; i++) {

		urb = usb_alloc_urb(0, GFP_KERNEL);
		if (!urb) {
			cx231xx_err(DRIVER_NAME
				    ": cannot alloc isoc_ctl.urb %i\n", i);
			cx231xx_uninit_vbi_isoc(dev);
			return -ENOMEM;
		}
		dev->vbi_mode.isoc_ctl.urb[i] = urb;
		urb->transfer_flags = 0;

		dev->vbi_mode.isoc_ctl.transfer_buffer[i] =
		    kzalloc(sb_size, GFP_KERNEL);
		if (!dev->vbi_mode.isoc_ctl.transfer_buffer[i]) {
			cx231xx_err(DRIVER_NAME
				    ": unable to allocate %i bytes for transfer"
				    " buffer %i%s\n", sb_size, i,
				    in_interrupt() ? " while in int" : "");
			cx231xx_uninit_vbi_isoc(dev);
			return -ENOMEM;
		}

		pipe = usb_rcvbulkpipe(dev->udev, dev->vbi_mode.end_point_addr);
		usb_fill_bulk_urb(urb, dev->udev, pipe,
				  dev->vbi_mode.isoc_ctl.transfer_buffer[i],
				  sb_size, cx231xx_irq_vbi_callback, dma_q);
	}

	init_waitqueue_head(&dma_q->wq);

	/* submit urbs and enables IRQ */
	for (i = 0; i < dev->vbi_mode.isoc_ctl.num_bufs; i++) {
		rc = usb_submit_urb(dev->vbi_mode.isoc_ctl.urb[i], GFP_ATOMIC);
		if (rc) {
			cx231xx_err(DRIVER_NAME
				    ": submit of urb %i failed (error=%i)\n", i,
				    rc);
			cx231xx_uninit_vbi_isoc(dev);
			return rc;
		}
	}

	cx231xx_capture_start(dev, 1, Vbi);

	return 0;
}
EXPORT_SYMBOL_GPL(cx231xx_init_vbi_isoc);

u32 cx231xx_get_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
			 u8 sav_eav, u8 *p_buffer, u32 buffer_size)
{
	u32 bytes_copied = 0;
	int current_field = -1;

	switch (sav_eav) {

	case SAV_VBI_FIELD1:
		current_field = 1;
		break;

	case SAV_VBI_FIELD2:
		current_field = 2;
		break;
	default:
		break;
	}

	if (current_field < 0)
		return bytes_copied;

	dma_q->last_sav = sav_eav;

	bytes_copied =
	    cx231xx_copy_vbi_line(dev, dma_q, p_buffer, buffer_size,
				  current_field);

	return bytes_copied;
}

/*
 * Announces that a buffer were filled and request the next
 */
static inline void vbi_buffer_filled(struct cx231xx *dev,
				     struct cx231xx_dmaqueue *dma_q,
				     struct cx231xx_buffer *buf)
{
	/* Advice that buffer was filled */
	/* cx231xx_info(DRIVER_NAME "[%p/%d] wakeup\n", buf, buf->vb.i); */

	buf->vb.state = VIDEOBUF_DONE;
	buf->vb.field_count++;
	do_gettimeofday(&buf->vb.ts);

	dev->vbi_mode.isoc_ctl.buf = NULL;

	list_del(&buf->vb.queue);
	wake_up(&buf->vb.done);
}

u32 cx231xx_copy_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
			  u8 *p_line, u32 length, int field_number)
{
	u32 bytes_to_copy;
	struct cx231xx_buffer *buf;
	u32 _line_size = dev->width * 2;

	if (dma_q->current_field != field_number)
		cx231xx_reset_vbi_buffer(dev, dma_q);

	/* get the buffer pointer */
	buf = dev->vbi_mode.isoc_ctl.buf;

	/* Remember the field number for next time */
	dma_q->current_field = field_number;

	bytes_to_copy = dma_q->bytes_left_in_line;
	if (bytes_to_copy > length)
		bytes_to_copy = length;

	if (dma_q->lines_completed >= dma_q->lines_per_field) {
		dma_q->bytes_left_in_line -= bytes_to_copy;
		dma_q->is_partial_line =
		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
		return 0;
	}

	dma_q->is_partial_line = 1;

	/* If we don't have a buffer, just return the number of bytes we would
	   have copied if we had a buffer. */
	if (!buf) {
		dma_q->bytes_left_in_line -= bytes_to_copy;
		dma_q->is_partial_line =
		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
		return bytes_to_copy;
	}

	/* copy the data to video buffer */
	cx231xx_do_vbi_copy(dev, dma_q, p_line, bytes_to_copy);

	dma_q->pos += bytes_to_copy;
	dma_q->bytes_left_in_line -= bytes_to_copy;

	if (dma_q->bytes_left_in_line == 0) {

		dma_q->bytes_left_in_line = _line_size;
		dma_q->lines_completed++;
		dma_q->is_partial_line = 0;

		if (cx231xx_is_vbi_buffer_done(dev, dma_q) && buf) {

			vbi_buffer_filled(dev, dma_q, buf);

			dma_q->pos = 0;
			buf = NULL;
			dma_q->lines_completed = 0;
		}
	}

	return bytes_to_copy;
}

/*
 * video-buf generic routine to get the next available buffer
 */
static inline void get_next_vbi_buf(struct cx231xx_dmaqueue *dma_q,
				    struct cx231xx_buffer **buf)
{
	struct cx231xx_video_mode *vmode =
	    container_of(dma_q, struct cx231xx_video_mode, vidq);
	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
	char *outp;

	if (list_empty(&dma_q->active)) {
		cx231xx_err(DRIVER_NAME ": No active queue to serve\n");
		dev->vbi_mode.isoc_ctl.buf = NULL;
		*buf = NULL;
		return;
	}

	/* Get the next buffer */
	*buf = list_entry(dma_q->active.next, struct cx231xx_buffer, vb.queue);

	/* Cleans up buffer - Usefull for testing for frame/URB loss */
	outp = videobuf_to_vmalloc(&(*buf)->vb);
	memset(outp, 0, (*buf)->vb.size);

	dev->vbi_mode.isoc_ctl.buf = *buf;

	return;
}

void cx231xx_reset_vbi_buffer(struct cx231xx *dev,
			      struct cx231xx_dmaqueue *dma_q)
{
	struct cx231xx_buffer *buf;

	buf = dev->vbi_mode.isoc_ctl.buf;

	if (buf == NULL) {
		/* first try to get the buffer */
		get_next_vbi_buf(dma_q, &buf);

		dma_q->pos = 0;
		dma_q->current_field = -1;
	}

	dma_q->bytes_left_in_line = dev->width << 1;
	dma_q->lines_completed = 0;
}

int cx231xx_do_vbi_copy(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
			u8 *p_buffer, u32 bytes_to_copy)
{
	u8 *p_out_buffer = NULL;
	u32 current_line_bytes_copied = 0;
	struct cx231xx_buffer *buf;
	u32 _line_size = dev->width << 1;
	void *startwrite;
	int offset, lencopy;

	buf = dev->vbi_mode.isoc_ctl.buf;

	if (buf == NULL)
		return -EINVAL;

	p_out_buffer = videobuf_to_vmalloc(&buf->vb);

	if (dma_q->bytes_left_in_line != _line_size) {
		current_line_bytes_copied =
		    _line_size - dma_q->bytes_left_in_line;
	}

	offset = (dma_q->lines_completed * _line_size) +
		 current_line_bytes_copied;

	/* prepare destination address */
	startwrite = p_out_buffer + offset;

	lencopy = dma_q->bytes_left_in_line > bytes_to_copy ?
		  bytes_to_copy : dma_q->bytes_left_in_line;

	memcpy(startwrite, p_buffer, lencopy);

	return 0;
}

u8 cx231xx_is_vbi_buffer_done(struct cx231xx *dev,
			      struct cx231xx_dmaqueue *dma_q)
{
	u32 height = 0;

	height = ((dev->norm & V4L2_STD_625_50) ?
		  PAL_VBI_LINES : NTSC_VBI_LINES);
	return (dma_q->lines_completed == height) ? 1 : 0;
}