1 /*
2    cx231xx_vbi.c - driver for Conexant Cx23100/101/102 USB video capture devices
3 
4    Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
5 	Based on cx88 driver
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 2 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program; if not, write to the Free Software
19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 #include "cx231xx.h"
23 #include <linux/init.h>
24 #include <linux/list.h>
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/bitmap.h>
28 #include <linux/i2c.h>
29 #include <linux/mm.h>
30 #include <linux/mutex.h>
31 #include <linux/slab.h>
32 
33 #include <media/v4l2-common.h>
34 #include <media/v4l2-ioctl.h>
35 #include <media/drv-intf/msp3400.h>
36 #include <media/tuner.h>
37 
38 #include "cx231xx-vbi.h"
39 
40 static inline void print_err_status(struct cx231xx *dev, int packet, int status)
41 {
42 	char *errmsg = "Unknown";
43 
44 	switch (status) {
45 	case -ENOENT:
46 		errmsg = "unlinked synchronously";
47 		break;
48 	case -ECONNRESET:
49 		errmsg = "unlinked asynchronously";
50 		break;
51 	case -ENOSR:
52 		errmsg = "Buffer error (overrun)";
53 		break;
54 	case -EPIPE:
55 		errmsg = "Stalled (device not responding)";
56 		break;
57 	case -EOVERFLOW:
58 		errmsg = "Babble (bad cable?)";
59 		break;
60 	case -EPROTO:
61 		errmsg = "Bit-stuff error (bad cable?)";
62 		break;
63 	case -EILSEQ:
64 		errmsg = "CRC/Timeout (could be anything)";
65 		break;
66 	case -ETIME:
67 		errmsg = "Device does not respond";
68 		break;
69 	}
70 	if (packet < 0) {
71 		dev_err(dev->dev,
72 			"URB status %d [%s].\n", status, errmsg);
73 	} else {
74 		dev_err(dev->dev,
75 			"URB packet %d, status %d [%s].\n",
76 			packet, status, errmsg);
77 	}
78 }
79 
80 /*
81  * Controls the isoc copy of each urb packet
82  */
83 static inline int cx231xx_isoc_vbi_copy(struct cx231xx *dev, struct urb *urb)
84 {
85 	struct cx231xx_dmaqueue *dma_q = urb->context;
86 	int rc = 1;
87 	unsigned char *p_buffer;
88 	u32 bytes_parsed = 0, buffer_size = 0;
89 	u8 sav_eav = 0;
90 
91 	if (!dev)
92 		return 0;
93 
94 	if (dev->state & DEV_DISCONNECTED)
95 		return 0;
96 
97 	if (urb->status < 0) {
98 		print_err_status(dev, -1, urb->status);
99 		if (urb->status == -ENOENT)
100 			return 0;
101 	}
102 
103 	/* get buffer pointer and length */
104 	p_buffer = urb->transfer_buffer;
105 	buffer_size = urb->actual_length;
106 
107 	if (buffer_size > 0) {
108 		bytes_parsed = 0;
109 
110 		if (dma_q->is_partial_line) {
111 			/* Handle the case where we were working on a partial
112 			   line */
113 			sav_eav = dma_q->last_sav;
114 		} else {
115 			/* Check for a SAV/EAV overlapping the
116 			   buffer boundary */
117 
118 			sav_eav = cx231xx_find_boundary_SAV_EAV(p_buffer,
119 							  dma_q->partial_buf,
120 							  &bytes_parsed);
121 		}
122 
123 		sav_eav &= 0xF0;
124 		/* Get the first line if we have some portion of an SAV/EAV from
125 		   the last buffer or a partial line */
126 		if (sav_eav) {
127 			bytes_parsed += cx231xx_get_vbi_line(dev, dma_q,
128 				sav_eav,		       /* SAV/EAV */
129 				p_buffer + bytes_parsed,       /* p_buffer */
130 				buffer_size - bytes_parsed);   /* buffer size */
131 		}
132 
133 		/* Now parse data that is completely in this buffer */
134 		dma_q->is_partial_line = 0;
135 
136 		while (bytes_parsed < buffer_size) {
137 			u32 bytes_used = 0;
138 
139 			sav_eav = cx231xx_find_next_SAV_EAV(
140 				p_buffer + bytes_parsed,	/* p_buffer */
141 				buffer_size - bytes_parsed, /* buffer size */
142 				&bytes_used);	/* bytes used to get SAV/EAV */
143 
144 			bytes_parsed += bytes_used;
145 
146 			sav_eav &= 0xF0;
147 			if (sav_eav && (bytes_parsed < buffer_size)) {
148 				bytes_parsed += cx231xx_get_vbi_line(dev,
149 					dma_q, sav_eav,	/* SAV/EAV */
150 					p_buffer+bytes_parsed, /* p_buffer */
151 					buffer_size-bytes_parsed);/*buf size*/
152 			}
153 		}
154 
155 		/* Save the last four bytes of the buffer so we can
156 		check the buffer boundary condition next time */
157 		memcpy(dma_q->partial_buf, p_buffer + buffer_size - 4, 4);
158 		bytes_parsed = 0;
159 	}
160 
161 	return rc;
162 }
163 
164 /* ------------------------------------------------------------------
165 	Vbi buf operations
166    ------------------------------------------------------------------*/
167 
168 static int
169 vbi_buffer_setup(struct videobuf_queue *vq, unsigned int *count,
170 		 unsigned int *size)
171 {
172 	struct cx231xx_fh *fh = vq->priv_data;
173 	struct cx231xx *dev = fh->dev;
174 	u32 height = 0;
175 
176 	height = ((dev->norm & V4L2_STD_625_50) ?
177 		  PAL_VBI_LINES : NTSC_VBI_LINES);
178 
179 	*size = (dev->width * height * 2 * 2);
180 	if (0 == *count)
181 		*count = CX231XX_DEF_VBI_BUF;
182 
183 	if (*count < CX231XX_MIN_BUF)
184 		*count = CX231XX_MIN_BUF;
185 
186 	return 0;
187 }
188 
189 /* This is called *without* dev->slock held; please keep it that way */
190 static void free_buffer(struct videobuf_queue *vq, struct cx231xx_buffer *buf)
191 {
192 	struct cx231xx_fh *fh = vq->priv_data;
193 	struct cx231xx *dev = fh->dev;
194 	unsigned long flags = 0;
195 	BUG_ON(in_interrupt());
196 
197 	/* We used to wait for the buffer to finish here, but this didn't work
198 	   because, as we were keeping the state as VIDEOBUF_QUEUED,
199 	   videobuf_queue_cancel marked it as finished for us.
200 	   (Also, it could wedge forever if the hardware was misconfigured.)
201 
202 	   This should be safe; by the time we get here, the buffer isn't
203 	   queued anymore. If we ever start marking the buffers as
204 	   VIDEOBUF_ACTIVE, it won't be, though.
205 	 */
206 	spin_lock_irqsave(&dev->vbi_mode.slock, flags);
207 	if (dev->vbi_mode.bulk_ctl.buf == buf)
208 		dev->vbi_mode.bulk_ctl.buf = NULL;
209 	spin_unlock_irqrestore(&dev->vbi_mode.slock, flags);
210 
211 	videobuf_vmalloc_free(&buf->vb);
212 	buf->vb.state = VIDEOBUF_NEEDS_INIT;
213 }
214 
215 static int
216 vbi_buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
217 		   enum v4l2_field field)
218 {
219 	struct cx231xx_fh *fh = vq->priv_data;
220 	struct cx231xx_buffer *buf =
221 	    container_of(vb, struct cx231xx_buffer, vb);
222 	struct cx231xx *dev = fh->dev;
223 	int rc = 0, urb_init = 0;
224 	u32 height = 0;
225 
226 	height = ((dev->norm & V4L2_STD_625_50) ?
227 		  PAL_VBI_LINES : NTSC_VBI_LINES);
228 	buf->vb.size = ((dev->width << 1) * height * 2);
229 
230 	if (0 != buf->vb.baddr && buf->vb.bsize < buf->vb.size)
231 		return -EINVAL;
232 
233 	buf->vb.width = dev->width;
234 	buf->vb.height = height;
235 	buf->vb.field = field;
236 	buf->vb.field = V4L2_FIELD_SEQ_TB;
237 
238 	if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
239 		rc = videobuf_iolock(vq, &buf->vb, NULL);
240 		if (rc < 0)
241 			goto fail;
242 	}
243 
244 	if (!dev->vbi_mode.bulk_ctl.num_bufs)
245 		urb_init = 1;
246 
247 	if (urb_init) {
248 		rc = cx231xx_init_vbi_isoc(dev, CX231XX_NUM_VBI_PACKETS,
249 					   CX231XX_NUM_VBI_BUFS,
250 					   dev->vbi_mode.alt_max_pkt_size[0],
251 					   cx231xx_isoc_vbi_copy);
252 		if (rc < 0)
253 			goto fail;
254 	}
255 
256 	buf->vb.state = VIDEOBUF_PREPARED;
257 	return 0;
258 
259 fail:
260 	free_buffer(vq, buf);
261 	return rc;
262 }
263 
264 static void
265 vbi_buffer_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
266 {
267 	struct cx231xx_buffer *buf =
268 	    container_of(vb, struct cx231xx_buffer, vb);
269 	struct cx231xx_fh *fh = vq->priv_data;
270 	struct cx231xx *dev = fh->dev;
271 	struct cx231xx_dmaqueue *vidq = &dev->vbi_mode.vidq;
272 
273 	buf->vb.state = VIDEOBUF_QUEUED;
274 	list_add_tail(&buf->vb.queue, &vidq->active);
275 
276 }
277 
278 static void vbi_buffer_release(struct videobuf_queue *vq,
279 			       struct videobuf_buffer *vb)
280 {
281 	struct cx231xx_buffer *buf =
282 	    container_of(vb, struct cx231xx_buffer, vb);
283 
284 
285 	free_buffer(vq, buf);
286 }
287 
288 const struct videobuf_queue_ops cx231xx_vbi_qops = {
289 	.buf_setup   = vbi_buffer_setup,
290 	.buf_prepare = vbi_buffer_prepare,
291 	.buf_queue   = vbi_buffer_queue,
292 	.buf_release = vbi_buffer_release,
293 };
294 
295 /* ------------------------------------------------------------------
296 	URB control
297    ------------------------------------------------------------------*/
298 
299 /*
300  * IRQ callback, called by URB callback
301  */
302 static void cx231xx_irq_vbi_callback(struct urb *urb)
303 {
304 	struct cx231xx_dmaqueue *dma_q = urb->context;
305 	struct cx231xx_video_mode *vmode =
306 	    container_of(dma_q, struct cx231xx_video_mode, vidq);
307 	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
308 
309 	switch (urb->status) {
310 	case 0:		/* success */
311 	case -ETIMEDOUT:	/* NAK */
312 		break;
313 	case -ECONNRESET:	/* kill */
314 	case -ENOENT:
315 	case -ESHUTDOWN:
316 		return;
317 	default:		/* error */
318 		dev_err(dev->dev,
319 			"urb completition error %d.\n",	urb->status);
320 		break;
321 	}
322 
323 	/* Copy data from URB */
324 	spin_lock(&dev->vbi_mode.slock);
325 	dev->vbi_mode.bulk_ctl.bulk_copy(dev, urb);
326 	spin_unlock(&dev->vbi_mode.slock);
327 
328 	/* Reset status */
329 	urb->status = 0;
330 
331 	urb->status = usb_submit_urb(urb, GFP_ATOMIC);
332 	if (urb->status) {
333 		dev_err(dev->dev, "urb resubmit failed (error=%i)\n",
334 			urb->status);
335 	}
336 }
337 
338 /*
339  * Stop and Deallocate URBs
340  */
341 void cx231xx_uninit_vbi_isoc(struct cx231xx *dev)
342 {
343 	struct urb *urb;
344 	int i;
345 
346 	dev_dbg(dev->dev, "called cx231xx_uninit_vbi_isoc\n");
347 
348 	dev->vbi_mode.bulk_ctl.nfields = -1;
349 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
350 		urb = dev->vbi_mode.bulk_ctl.urb[i];
351 		if (urb) {
352 			if (!irqs_disabled())
353 				usb_kill_urb(urb);
354 			else
355 				usb_unlink_urb(urb);
356 
357 			if (dev->vbi_mode.bulk_ctl.transfer_buffer[i]) {
358 
359 				kfree(dev->vbi_mode.bulk_ctl.
360 				      transfer_buffer[i]);
361 				dev->vbi_mode.bulk_ctl.transfer_buffer[i] =
362 				    NULL;
363 			}
364 			usb_free_urb(urb);
365 			dev->vbi_mode.bulk_ctl.urb[i] = NULL;
366 		}
367 		dev->vbi_mode.bulk_ctl.transfer_buffer[i] = NULL;
368 	}
369 
370 	kfree(dev->vbi_mode.bulk_ctl.urb);
371 	kfree(dev->vbi_mode.bulk_ctl.transfer_buffer);
372 
373 	dev->vbi_mode.bulk_ctl.urb = NULL;
374 	dev->vbi_mode.bulk_ctl.transfer_buffer = NULL;
375 	dev->vbi_mode.bulk_ctl.num_bufs = 0;
376 
377 	cx231xx_capture_start(dev, 0, Vbi);
378 }
379 EXPORT_SYMBOL_GPL(cx231xx_uninit_vbi_isoc);
380 
381 /*
382  * Allocate URBs and start IRQ
383  */
384 int cx231xx_init_vbi_isoc(struct cx231xx *dev, int max_packets,
385 			  int num_bufs, int max_pkt_size,
386 			  int (*bulk_copy) (struct cx231xx *dev,
387 					    struct urb *urb))
388 {
389 	struct cx231xx_dmaqueue *dma_q = &dev->vbi_mode.vidq;
390 	int i;
391 	int sb_size, pipe;
392 	struct urb *urb;
393 	int rc;
394 
395 	dev_dbg(dev->dev, "called cx231xx_vbi_isoc\n");
396 
397 	/* De-allocates all pending stuff */
398 	cx231xx_uninit_vbi_isoc(dev);
399 
400 	/* clear if any halt */
401 	usb_clear_halt(dev->udev,
402 		       usb_rcvbulkpipe(dev->udev,
403 				       dev->vbi_mode.end_point_addr));
404 
405 	dev->vbi_mode.bulk_ctl.bulk_copy = bulk_copy;
406 	dev->vbi_mode.bulk_ctl.num_bufs = num_bufs;
407 	dma_q->pos = 0;
408 	dma_q->is_partial_line = 0;
409 	dma_q->last_sav = 0;
410 	dma_q->current_field = -1;
411 	dma_q->bytes_left_in_line = dev->width << 1;
412 	dma_q->lines_per_field = ((dev->norm & V4L2_STD_625_50) ?
413 				  PAL_VBI_LINES : NTSC_VBI_LINES);
414 	dma_q->lines_completed = 0;
415 	for (i = 0; i < 8; i++)
416 		dma_q->partial_buf[i] = 0;
417 
418 	dev->vbi_mode.bulk_ctl.urb = kcalloc(num_bufs, sizeof(void *),
419 					     GFP_KERNEL);
420 	if (!dev->vbi_mode.bulk_ctl.urb) {
421 		dev_err(dev->dev,
422 			"cannot alloc memory for usb buffers\n");
423 		return -ENOMEM;
424 	}
425 
426 	dev->vbi_mode.bulk_ctl.transfer_buffer =
427 	    kcalloc(num_bufs, sizeof(void *), GFP_KERNEL);
428 	if (!dev->vbi_mode.bulk_ctl.transfer_buffer) {
429 		dev_err(dev->dev,
430 			"cannot allocate memory for usbtransfer\n");
431 		kfree(dev->vbi_mode.bulk_ctl.urb);
432 		return -ENOMEM;
433 	}
434 
435 	dev->vbi_mode.bulk_ctl.max_pkt_size = max_pkt_size;
436 	dev->vbi_mode.bulk_ctl.buf = NULL;
437 
438 	sb_size = max_packets * dev->vbi_mode.bulk_ctl.max_pkt_size;
439 
440 	/* allocate urbs and transfer buffers */
441 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
442 
443 		urb = usb_alloc_urb(0, GFP_KERNEL);
444 		if (!urb) {
445 			cx231xx_uninit_vbi_isoc(dev);
446 			return -ENOMEM;
447 		}
448 		dev->vbi_mode.bulk_ctl.urb[i] = urb;
449 		urb->transfer_flags = 0;
450 
451 		dev->vbi_mode.bulk_ctl.transfer_buffer[i] =
452 		    kzalloc(sb_size, GFP_KERNEL);
453 		if (!dev->vbi_mode.bulk_ctl.transfer_buffer[i]) {
454 			dev_err(dev->dev,
455 				"unable to allocate %i bytes for transfer buffer %i%s\n",
456 				sb_size, i,
457 				in_interrupt() ? " while in int" : "");
458 			cx231xx_uninit_vbi_isoc(dev);
459 			return -ENOMEM;
460 		}
461 
462 		pipe = usb_rcvbulkpipe(dev->udev, dev->vbi_mode.end_point_addr);
463 		usb_fill_bulk_urb(urb, dev->udev, pipe,
464 				  dev->vbi_mode.bulk_ctl.transfer_buffer[i],
465 				  sb_size, cx231xx_irq_vbi_callback, dma_q);
466 	}
467 
468 	init_waitqueue_head(&dma_q->wq);
469 
470 	/* submit urbs and enables IRQ */
471 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
472 		rc = usb_submit_urb(dev->vbi_mode.bulk_ctl.urb[i], GFP_ATOMIC);
473 		if (rc) {
474 			dev_err(dev->dev,
475 				"submit of urb %i failed (error=%i)\n", i, rc);
476 			cx231xx_uninit_vbi_isoc(dev);
477 			return rc;
478 		}
479 	}
480 
481 	cx231xx_capture_start(dev, 1, Vbi);
482 
483 	return 0;
484 }
485 EXPORT_SYMBOL_GPL(cx231xx_init_vbi_isoc);
486 
487 u32 cx231xx_get_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
488 			 u8 sav_eav, u8 *p_buffer, u32 buffer_size)
489 {
490 	u32 bytes_copied = 0;
491 	int current_field = -1;
492 
493 	switch (sav_eav) {
494 
495 	case SAV_VBI_FIELD1:
496 		current_field = 1;
497 		break;
498 
499 	case SAV_VBI_FIELD2:
500 		current_field = 2;
501 		break;
502 	default:
503 		break;
504 	}
505 
506 	if (current_field < 0)
507 		return bytes_copied;
508 
509 	dma_q->last_sav = sav_eav;
510 
511 	bytes_copied =
512 	    cx231xx_copy_vbi_line(dev, dma_q, p_buffer, buffer_size,
513 				  current_field);
514 
515 	return bytes_copied;
516 }
517 
518 /*
519  * Announces that a buffer were filled and request the next
520  */
521 static inline void vbi_buffer_filled(struct cx231xx *dev,
522 				     struct cx231xx_dmaqueue *dma_q,
523 				     struct cx231xx_buffer *buf)
524 {
525 	/* Advice that buffer was filled */
526 	/* dev_dbg(dev->dev, "[%p/%d] wakeup\n", buf, buf->vb.i); */
527 
528 	buf->vb.state = VIDEOBUF_DONE;
529 	buf->vb.field_count++;
530 	v4l2_get_timestamp(&buf->vb.ts);
531 
532 	dev->vbi_mode.bulk_ctl.buf = NULL;
533 
534 	list_del(&buf->vb.queue);
535 	wake_up(&buf->vb.done);
536 }
537 
538 u32 cx231xx_copy_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
539 			  u8 *p_line, u32 length, int field_number)
540 {
541 	u32 bytes_to_copy;
542 	struct cx231xx_buffer *buf;
543 	u32 _line_size = dev->width * 2;
544 
545 	if (dma_q->current_field == -1) {
546 		/* Just starting up */
547 		cx231xx_reset_vbi_buffer(dev, dma_q);
548 	}
549 
550 	if (dma_q->current_field != field_number)
551 		dma_q->lines_completed = 0;
552 
553 	/* get the buffer pointer */
554 	buf = dev->vbi_mode.bulk_ctl.buf;
555 
556 	/* Remember the field number for next time */
557 	dma_q->current_field = field_number;
558 
559 	bytes_to_copy = dma_q->bytes_left_in_line;
560 	if (bytes_to_copy > length)
561 		bytes_to_copy = length;
562 
563 	if (dma_q->lines_completed >= dma_q->lines_per_field) {
564 		dma_q->bytes_left_in_line -= bytes_to_copy;
565 		dma_q->is_partial_line =
566 		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
567 		return 0;
568 	}
569 
570 	dma_q->is_partial_line = 1;
571 
572 	/* If we don't have a buffer, just return the number of bytes we would
573 	   have copied if we had a buffer. */
574 	if (!buf) {
575 		dma_q->bytes_left_in_line -= bytes_to_copy;
576 		dma_q->is_partial_line =
577 		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
578 		return bytes_to_copy;
579 	}
580 
581 	/* copy the data to video buffer */
582 	cx231xx_do_vbi_copy(dev, dma_q, p_line, bytes_to_copy);
583 
584 	dma_q->pos += bytes_to_copy;
585 	dma_q->bytes_left_in_line -= bytes_to_copy;
586 
587 	if (dma_q->bytes_left_in_line == 0) {
588 
589 		dma_q->bytes_left_in_line = _line_size;
590 		dma_q->lines_completed++;
591 		dma_q->is_partial_line = 0;
592 
593 		if (cx231xx_is_vbi_buffer_done(dev, dma_q) && buf) {
594 
595 			vbi_buffer_filled(dev, dma_q, buf);
596 
597 			dma_q->pos = 0;
598 			dma_q->lines_completed = 0;
599 			cx231xx_reset_vbi_buffer(dev, dma_q);
600 		}
601 	}
602 
603 	return bytes_to_copy;
604 }
605 
606 /*
607  * video-buf generic routine to get the next available buffer
608  */
609 static inline void get_next_vbi_buf(struct cx231xx_dmaqueue *dma_q,
610 				    struct cx231xx_buffer **buf)
611 {
612 	struct cx231xx_video_mode *vmode =
613 	    container_of(dma_q, struct cx231xx_video_mode, vidq);
614 	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
615 	char *outp;
616 
617 	if (list_empty(&dma_q->active)) {
618 		dev_err(dev->dev, "No active queue to serve\n");
619 		dev->vbi_mode.bulk_ctl.buf = NULL;
620 		*buf = NULL;
621 		return;
622 	}
623 
624 	/* Get the next buffer */
625 	*buf = list_entry(dma_q->active.next, struct cx231xx_buffer, vb.queue);
626 
627 	/* Cleans up buffer - Useful for testing for frame/URB loss */
628 	outp = videobuf_to_vmalloc(&(*buf)->vb);
629 	memset(outp, 0, (*buf)->vb.size);
630 
631 	dev->vbi_mode.bulk_ctl.buf = *buf;
632 
633 	return;
634 }
635 
636 void cx231xx_reset_vbi_buffer(struct cx231xx *dev,
637 			      struct cx231xx_dmaqueue *dma_q)
638 {
639 	struct cx231xx_buffer *buf;
640 
641 	buf = dev->vbi_mode.bulk_ctl.buf;
642 
643 	if (buf == NULL) {
644 		/* first try to get the buffer */
645 		get_next_vbi_buf(dma_q, &buf);
646 
647 		dma_q->pos = 0;
648 		dma_q->current_field = -1;
649 	}
650 
651 	dma_q->bytes_left_in_line = dev->width << 1;
652 	dma_q->lines_completed = 0;
653 }
654 
655 int cx231xx_do_vbi_copy(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
656 			u8 *p_buffer, u32 bytes_to_copy)
657 {
658 	u8 *p_out_buffer = NULL;
659 	u32 current_line_bytes_copied = 0;
660 	struct cx231xx_buffer *buf;
661 	u32 _line_size = dev->width << 1;
662 	void *startwrite;
663 	int offset, lencopy;
664 
665 	buf = dev->vbi_mode.bulk_ctl.buf;
666 
667 	if (buf == NULL)
668 		return -EINVAL;
669 
670 	p_out_buffer = videobuf_to_vmalloc(&buf->vb);
671 
672 	if (dma_q->bytes_left_in_line != _line_size) {
673 		current_line_bytes_copied =
674 		    _line_size - dma_q->bytes_left_in_line;
675 	}
676 
677 	offset = (dma_q->lines_completed * _line_size) +
678 		 current_line_bytes_copied;
679 
680 	if (dma_q->current_field == 2) {
681 		/* Populate the second half of the frame */
682 		offset += (dev->width * 2 * dma_q->lines_per_field);
683 	}
684 
685 	/* prepare destination address */
686 	startwrite = p_out_buffer + offset;
687 
688 	lencopy = dma_q->bytes_left_in_line > bytes_to_copy ?
689 		  bytes_to_copy : dma_q->bytes_left_in_line;
690 
691 	memcpy(startwrite, p_buffer, lencopy);
692 
693 	return 0;
694 }
695 
696 u8 cx231xx_is_vbi_buffer_done(struct cx231xx *dev,
697 			      struct cx231xx_dmaqueue *dma_q)
698 {
699 	u32 height = 0;
700 
701 	height = ((dev->norm & V4L2_STD_625_50) ?
702 		  PAL_VBI_LINES : NTSC_VBI_LINES);
703 	if (dma_q->lines_completed == height && dma_q->current_field == 2)
704 		return 1;
705 	else
706 		return 0;
707 }
708