1/*
2   em28xx-vbi.c - VBI driver for em28xx
3
4   Copyright (C) 2009 Devin Heitmueller <dheitmueller@kernellabs.com>
5
6   This work was sponsored by EyeMagnet Limited.
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21   02110-1301, USA.
22 */
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/hardirq.h>
27#include <linux/init.h>
28
29#include "em28xx.h"
30
31static unsigned int vbibufs = 5;
32module_param(vbibufs, int, 0644);
33MODULE_PARM_DESC(vbibufs, "number of vbi buffers, range 2-32");
34
35static unsigned int vbi_debug;
36module_param(vbi_debug, int, 0644);
37MODULE_PARM_DESC(vbi_debug, "enable debug messages [vbi]");
38
39#define dprintk(level, fmt, arg...)	if (vbi_debug >= level) \
40	printk(KERN_DEBUG "%s: " fmt, dev->core->name , ## arg)
41
42/* ------------------------------------------------------------------ */
43
44static void
45free_buffer(struct videobuf_queue *vq, struct em28xx_buffer *buf)
46{
47	struct em28xx_fh     *fh  = vq->priv_data;
48	struct em28xx        *dev = fh->dev;
49	unsigned long flags = 0;
50	if (in_interrupt())
51		BUG();
52
53	/* We used to wait for the buffer to finish here, but this didn't work
54	   because, as we were keeping the state as VIDEOBUF_QUEUED,
55	   videobuf_queue_cancel marked it as finished for us.
56	   (Also, it could wedge forever if the hardware was misconfigured.)
57
58	   This should be safe; by the time we get here, the buffer isn't
59	   queued anymore. If we ever start marking the buffers as
60	   VIDEOBUF_ACTIVE, it won't be, though.
61	*/
62	spin_lock_irqsave(&dev->slock, flags);
63	if (dev->isoc_ctl.vbi_buf == buf)
64		dev->isoc_ctl.vbi_buf = NULL;
65	spin_unlock_irqrestore(&dev->slock, flags);
66
67	videobuf_vmalloc_free(&buf->vb);
68	buf->vb.state = VIDEOBUF_NEEDS_INIT;
69}
70
71static int
72vbi_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size)
73{
74	struct em28xx_fh     *fh  = q->priv_data;
75	struct em28xx        *dev = fh->dev;
76
77	*size = dev->vbi_width * dev->vbi_height * 2;
78
79	if (0 == *count)
80		*count = vbibufs;
81	if (*count < 2)
82		*count = 2;
83	if (*count > 32)
84		*count = 32;
85	return 0;
86}
87
88static int
89vbi_prepare(struct videobuf_queue *q, struct videobuf_buffer *vb,
90	    enum v4l2_field field)
91{
92	struct em28xx_fh     *fh  = q->priv_data;
93	struct em28xx        *dev = fh->dev;
94	struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
95	int                  rc = 0;
96
97	buf->vb.size = dev->vbi_width * dev->vbi_height * 2;
98
99	if (0 != buf->vb.baddr  &&  buf->vb.bsize < buf->vb.size)
100		return -EINVAL;
101
102	buf->vb.width  = dev->vbi_width;
103	buf->vb.height = dev->vbi_height;
104	buf->vb.field  = field;
105
106	if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
107		rc = videobuf_iolock(q, &buf->vb, NULL);
108		if (rc < 0)
109			goto fail;
110	}
111
112	buf->vb.state = VIDEOBUF_PREPARED;
113	return 0;
114
115fail:
116	free_buffer(q, buf);
117	return rc;
118}
119
120static void
121vbi_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
122{
123	struct em28xx_buffer    *buf     = container_of(vb,
124							struct em28xx_buffer,
125							vb);
126	struct em28xx_fh        *fh      = vq->priv_data;
127	struct em28xx           *dev     = fh->dev;
128	struct em28xx_dmaqueue  *vbiq    = &dev->vbiq;
129
130	buf->vb.state = VIDEOBUF_QUEUED;
131	list_add_tail(&buf->vb.queue, &vbiq->active);
132}
133
134static void vbi_release(struct videobuf_queue *q, struct videobuf_buffer *vb)
135{
136	struct em28xx_buffer *buf = container_of(vb, struct em28xx_buffer, vb);
137	free_buffer(q, buf);
138}
139
140struct videobuf_queue_ops em28xx_vbi_qops = {
141	.buf_setup    = vbi_setup,
142	.buf_prepare  = vbi_prepare,
143	.buf_queue    = vbi_queue,
144	.buf_release  = vbi_release,
145};
146