/*
 * Virtual Video driver - This code emulates a real video device with v4l2 api
 *
 * Copyright (c) 2006 by:
 *      Mauro Carvalho Chehab <mchehab--a.t--infradead.org>
 *      Ted Walther <ted--a.t--enumera.com>
 *      John Sokol <sokol--a.t--videotechnology.com>
 *      http://v4l.videotechnology.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the BSD Licence, 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/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/random.h>
#include <linux/version.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>
#include <linux/dma-mapping.h>
#ifdef CONFIG_VIDEO_V4L1_COMPAT
/* Include V4L1 specific functions. Should be removed soon */
#include <linux/videodev.h>
#endif
#include <linux/interrupt.h>
#include <media/videobuf-vmalloc.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <linux/kthread.h>
#include <linux/highmem.h>
#include <linux/freezer.h>

#define VIVI_MODULE_NAME "vivi"

/* Wake up at about 30 fps */
#define WAKE_NUMERATOR 30
#define WAKE_DENOMINATOR 1001
#define BUFFER_TIMEOUT     msecs_to_jiffies(500)  /* 0.5 seconds */

#include "font.h"

#define VIVI_MAJOR_VERSION 0
#define VIVI_MINOR_VERSION 5
#define VIVI_RELEASE 0
#define VIVI_VERSION \
	KERNEL_VERSION(VIVI_MAJOR_VERSION, VIVI_MINOR_VERSION, VIVI_RELEASE)

/* Declare static vars that will be used as parameters */
static unsigned int vid_limit = 16;	/* Video memory limit, in Mb */
static int video_nr = -1;		/* /dev/videoN, -1 for autodetect */
static int n_devs = 1;			/* Number of virtual devices */

/* supported controls */
static struct v4l2_queryctrl vivi_qctrl[] = {
	{
		.id            = V4L2_CID_AUDIO_VOLUME,
		.name          = "Volume",
		.minimum       = 0,
		.maximum       = 65535,
		.step          = 65535/100,
		.default_value = 65535,
		.flags         = 0,
		.type          = V4L2_CTRL_TYPE_INTEGER,
	}, {
		.id            = V4L2_CID_BRIGHTNESS,
		.type          = V4L2_CTRL_TYPE_INTEGER,
		.name          = "Brightness",
		.minimum       = 0,
		.maximum       = 255,
		.step          = 1,
		.default_value = 127,
		.flags         = 0,
	}, {
		.id            = V4L2_CID_CONTRAST,
		.type          = V4L2_CTRL_TYPE_INTEGER,
		.name          = "Contrast",
		.minimum       = 0,
		.maximum       = 255,
		.step          = 0x1,
		.default_value = 0x10,
		.flags         = 0,
	}, {
		.id            = V4L2_CID_SATURATION,
		.type          = V4L2_CTRL_TYPE_INTEGER,
		.name          = "Saturation",
		.minimum       = 0,
		.maximum       = 255,
		.step          = 0x1,
		.default_value = 127,
		.flags         = 0,
	}, {
		.id            = V4L2_CID_HUE,
		.type          = V4L2_CTRL_TYPE_INTEGER,
		.name          = "Hue",
		.minimum       = -128,
		.maximum       = 127,
		.step          = 0x1,
		.default_value = 0,
		.flags         = 0,
	}
};

static int qctl_regs[ARRAY_SIZE(vivi_qctrl)];

#define dprintk(dev, level, fmt, arg...)				\
	do {								\
		if (dev->vfd->debug >= (level))				\
			printk(KERN_DEBUG "vivi: " fmt , ## arg);	\
	} while (0)

/* ------------------------------------------------------------------
	Basic structures
   ------------------------------------------------------------------*/

struct vivi_fmt {
	char  *name;
	u32   fourcc;          /* v4l2 format id */
	int   depth;
};

static struct vivi_fmt format = {
	.name     = "4:2:2, packed, YUYV",
	.fourcc   = V4L2_PIX_FMT_YUYV,
	.depth    = 16,
};

struct sg_to_addr {
	int pos;
	struct scatterlist *sg;
};

/* buffer for one video frame */
struct vivi_buffer {
	/* common v4l buffer stuff -- must be first */
	struct videobuf_buffer vb;

	struct vivi_fmt        *fmt;
};

struct vivi_dmaqueue {
	struct list_head       active;

	/* thread for generating video stream*/
	struct task_struct         *kthread;
	wait_queue_head_t          wq;
	/* Counters to control fps rate */
	int                        frame;
	int                        ini_jiffies;
};

static LIST_HEAD(vivi_devlist);

struct vivi_dev {
	struct list_head           vivi_devlist;

	spinlock_t                 slock;
	struct mutex		   mutex;

	int                        users;

	/* various device info */
	struct video_device        *vfd;

	struct vivi_dmaqueue       vidq;

	/* Several counters */
	int                        h, m, s, ms;
	unsigned long              jiffies;
	char                       timestr[13];

	int			   mv_count;	/* Controls bars movement */
};

struct vivi_fh {
	struct vivi_dev            *dev;

	/* video capture */
	struct vivi_fmt            *fmt;
	unsigned int               width, height;
	struct videobuf_queue      vb_vidq;

	enum v4l2_buf_type         type;
};

/* ------------------------------------------------------------------
	DMA and thread functions
   ------------------------------------------------------------------*/

/* Bars and Colors should match positions */

enum colors {
	WHITE,
	AMBAR,
	CYAN,
	GREEN,
	MAGENTA,
	RED,
	BLUE,
	BLACK,
};

static u8 bars[8][3] = {
	/* R   G   B */
	{204, 204, 204},  /* white */
	{208, 208,   0},  /* ambar */
	{  0, 206, 206},  /* cyan */
	{  0, 239,   0},  /* green */
	{239,   0, 239},  /* magenta */
	{205,   0,   0},  /* red */
	{  0,   0, 255},  /* blue */
	{  0,   0,   0},  /* black */
};

#define TO_Y(r, g, b) \
	(((16829 * r + 33039 * g + 6416 * b  + 32768) >> 16) + 16)
/* RGB to  V(Cr) Color transform */
#define TO_V(r, g, b) \
	(((28784 * r - 24103 * g - 4681 * b  + 32768) >> 16) + 128)
/* RGB to  U(Cb) Color transform */
#define TO_U(r, g, b) \
	(((-9714 * r - 19070 * g + 28784 * b + 32768) >> 16) + 128)

#define TSTAMP_MIN_Y 24
#define TSTAMP_MAX_Y TSTAMP_MIN_Y+15
#define TSTAMP_MIN_X 64

static void gen_line(char *basep, int inipos, int wmax,
		int hmax, int line, int count, char *timestr)
{
	int  w, i, j, y;
	int pos = inipos;
	char *p, *s;
	u8   chr, r, g, b, color;

	/* We will just duplicate the second pixel at the packet */
	wmax /= 2;

	/* Generate a standard color bar pattern */
	for (w = 0; w < wmax; w++) {
		int colorpos = ((w + count) * 8/(wmax + 1)) % 8;
		r = bars[colorpos][0];
		g = bars[colorpos][1];
		b = bars[colorpos][2];

		for (color = 0; color < 4; color++) {
			p = basep + pos;

			switch (color) {
			case 0:
			case 2:
				*p = TO_Y(r, g, b);	/* Luma */
				break;
			case 1:
				*p = TO_U(r, g, b);	/* Cb */
				break;
			case 3:
				*p = TO_V(r, g, b);	/* Cr */
				break;
			}
			pos++;
		}
	}

	/* Checks if it is possible to show timestamp */
	if (TSTAMP_MAX_Y >= hmax)
		goto end;
	if (TSTAMP_MIN_X + strlen(timestr) >= wmax)
		goto end;

	/* Print stream time */
	if (line >= TSTAMP_MIN_Y && line <= TSTAMP_MAX_Y) {
		j = TSTAMP_MIN_X;
		for (s = timestr; *s; s++) {
			chr = rom8x16_bits[(*s-0x30)*16+line-TSTAMP_MIN_Y];
			for (i = 0; i < 7; i++) {
				if (chr & 1 << (7 - i)) {
					/* Font color*/
					r = 0;
					g = 198;
					b = 0;
				} else {
					/* Background color */
					r = bars[BLACK][0];
					g = bars[BLACK][1];
					b = bars[BLACK][2];
				}

				pos = inipos + j * 2;
				for (color = 0; color < 4; color++) {
					p = basep + pos;

					y = TO_Y(r, g, b);

					switch (color) {
					case 0:
					case 2:
						*p = TO_Y(r, g, b); /* Luma */
						break;
					case 1:
						*p = TO_U(r, g, b); /* Cb */
						break;
					case 3:
						*p = TO_V(r, g, b); /* Cr */
						break;
					}
					pos++;
				}
				j++;
			}
		}
	}

end:
	return;
}

static void vivi_fillbuff(struct vivi_dev *dev, struct vivi_buffer *buf)
{
	int h , pos = 0;
	int hmax  = buf->vb.height;
	int wmax  = buf->vb.width;
	struct timeval ts;
	char *tmpbuf;
	void *vbuf = videobuf_to_vmalloc(&buf->vb);

	if (!vbuf)
		return;

	tmpbuf = kmalloc(wmax * 2, GFP_ATOMIC);
	if (!tmpbuf)
		return;

	for (h = 0; h < hmax; h++) {
		gen_line(tmpbuf, 0, wmax, hmax, h, dev->mv_count,
			 dev->timestr);
		memcpy(vbuf + pos, tmpbuf, wmax * 2);
		pos += wmax*2;
	}

	dev->mv_count++;

	kfree(tmpbuf);

	/* Updates stream time */

	dev->ms += jiffies_to_msecs(jiffies-dev->jiffies);
	dev->jiffies = jiffies;
	if (dev->ms >= 1000) {
		dev->ms -= 1000;
		dev->s++;
		if (dev->s >= 60) {
			dev->s -= 60;
			dev->m++;
			if (dev->m > 60) {
				dev->m -= 60;
				dev->h++;
				if (dev->h > 24)
					dev->h -= 24;
			}
		}
	}
	sprintf(dev->timestr, "%02d:%02d:%02d:%03d",
			dev->h, dev->m, dev->s, dev->ms);

	dprintk(dev, 2, "vivifill at %s: Buffer 0x%08lx size= %d\n",
			dev->timestr, (unsigned long)tmpbuf, pos);

	/* Advice that buffer was filled */
	buf->vb.field_count++;
	do_gettimeofday(&ts);
	buf->vb.ts = ts;
	buf->vb.state = VIDEOBUF_DONE;
}

static void vivi_thread_tick(struct vivi_fh *fh)
{
	struct vivi_buffer *buf;
	struct vivi_dev *dev = fh->dev;
	struct vivi_dmaqueue *dma_q = &dev->vidq;

	unsigned long flags = 0;

	dprintk(dev, 1, "Thread tick\n");

	spin_lock_irqsave(&dev->slock, flags);
	if (list_empty(&dma_q->active)) {
		dprintk(dev, 1, "No active queue to serve\n");
		goto unlock;
	}

	buf = list_entry(dma_q->active.next,
			 struct vivi_buffer, vb.queue);

	/* Nobody is waiting on this buffer, return */
	if (!waitqueue_active(&buf->vb.done))
		goto unlock;

	list_del(&buf->vb.queue);

	do_gettimeofday(&buf->vb.ts);

	/* Fill buffer */
	vivi_fillbuff(dev, buf);
	dprintk(dev, 1, "filled buffer %p\n", buf);

	wake_up(&buf->vb.done);
	dprintk(dev, 2, "[%p/%d] wakeup\n", buf, buf->vb. i);
unlock:
	spin_unlock_irqrestore(&dev->slock, flags);
	return;
}

#define frames_to_ms(frames)					\
	((frames * WAKE_NUMERATOR * 1000) / WAKE_DENOMINATOR)

static void vivi_sleep(struct vivi_fh *fh)
{
	struct vivi_dev *dev = fh->dev;
	struct vivi_dmaqueue *dma_q = &dev->vidq;
	int timeout;
	DECLARE_WAITQUEUE(wait, current);

	dprintk(dev, 1, "%s dma_q=0x%08lx\n", __func__,
		(unsigned long)dma_q);

	add_wait_queue(&dma_q->wq, &wait);
	if (kthread_should_stop())
		goto stop_task;

	/* Calculate time to wake up */
	timeout = msecs_to_jiffies(frames_to_ms(1));

	vivi_thread_tick(fh);

	schedule_timeout_interruptible(timeout);

stop_task:
	remove_wait_queue(&dma_q->wq, &wait);
	try_to_freeze();
}

static int vivi_thread(void *data)
{
	struct vivi_fh  *fh = data;
	struct vivi_dev *dev = fh->dev;

	dprintk(dev, 1, "thread started\n");

	set_freezable();

	for (;;) {
		vivi_sleep(fh);

		if (kthread_should_stop())
			break;
	}
	dprintk(dev, 1, "thread: exit\n");
	return 0;
}

static int vivi_start_thread(struct vivi_fh *fh)
{
	struct vivi_dev *dev = fh->dev;
	struct vivi_dmaqueue *dma_q = &dev->vidq;

	dma_q->frame = 0;
	dma_q->ini_jiffies = jiffies;

	dprintk(dev, 1, "%s\n", __func__);

	dma_q->kthread = kthread_run(vivi_thread, fh, "vivi");

	if (IS_ERR(dma_q->kthread)) {
		printk(KERN_ERR "vivi: kernel_thread() failed\n");
		return PTR_ERR(dma_q->kthread);
	}
	/* Wakes thread */
	wake_up_interruptible(&dma_q->wq);

	dprintk(dev, 1, "returning from %s\n", __func__);
	return 0;
}

static void vivi_stop_thread(struct vivi_dmaqueue  *dma_q)
{
	struct vivi_dev *dev = container_of(dma_q, struct vivi_dev, vidq);

	dprintk(dev, 1, "%s\n", __func__);
	/* shutdown control thread */
	if (dma_q->kthread) {
		kthread_stop(dma_q->kthread);
		dma_q->kthread = NULL;
	}
}

/* ------------------------------------------------------------------
	Videobuf operations
   ------------------------------------------------------------------*/
static int
buffer_setup(struct videobuf_queue *vq, unsigned int *count, unsigned int *size)
{
	struct vivi_fh  *fh = vq->priv_data;
	struct vivi_dev *dev  = fh->dev;

	*size = fh->width*fh->height*2;

	if (0 == *count)
		*count = 32;

	while (*size * *count > vid_limit * 1024 * 1024)
		(*count)--;

	dprintk(dev, 1, "%s, count=%d, size=%d\n", __func__,
		*count, *size);

	return 0;
}

static void free_buffer(struct videobuf_queue *vq, struct vivi_buffer *buf)
{
	struct vivi_fh  *fh = vq->priv_data;
	struct vivi_dev *dev  = fh->dev;

	dprintk(dev, 1, "%s, state: %i\n", __func__, buf->vb.state);

	if (in_interrupt())
		BUG();

	videobuf_vmalloc_free(&buf->vb);
	dprintk(dev, 1, "free_buffer: freed\n");
	buf->vb.state = VIDEOBUF_NEEDS_INIT;
}

#define norm_maxw() 1024
#define norm_maxh() 768
static int
buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
						enum v4l2_field field)
{
	struct vivi_fh     *fh  = vq->priv_data;
	struct vivi_dev    *dev = fh->dev;
	struct vivi_buffer *buf = container_of(vb, struct vivi_buffer, vb);
	int rc;

	dprintk(dev, 1, "%s, field=%d\n", __func__, field);

	BUG_ON(NULL == fh->fmt);

	if (fh->width  < 48 || fh->width  > norm_maxw() ||
	    fh->height < 32 || fh->height > norm_maxh())
		return -EINVAL;

	buf->vb.size = fh->width*fh->height*2;
	if (0 != buf->vb.baddr  &&  buf->vb.bsize < buf->vb.size)
		return -EINVAL;

	/* These properties only change when queue is idle, see s_fmt */
	buf->fmt       = fh->fmt;
	buf->vb.width  = fh->width;
	buf->vb.height = fh->height;
	buf->vb.field  = field;

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

	buf->vb.state = VIDEOBUF_PREPARED;

	return 0;

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

static void
buffer_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
{
	struct vivi_buffer    *buf  = container_of(vb, struct vivi_buffer, vb);
	struct vivi_fh        *fh   = vq->priv_data;
	struct vivi_dev       *dev  = fh->dev;
	struct vivi_dmaqueue *vidq = &dev->vidq;

	dprintk(dev, 1, "%s\n", __func__);

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

static void buffer_release(struct videobuf_queue *vq,
			   struct videobuf_buffer *vb)
{
	struct vivi_buffer   *buf  = container_of(vb, struct vivi_buffer, vb);
	struct vivi_fh       *fh   = vq->priv_data;
	struct vivi_dev      *dev  = (struct vivi_dev *)fh->dev;

	dprintk(dev, 1, "%s\n", __func__);

	free_buffer(vq, buf);
}

static struct videobuf_queue_ops vivi_video_qops = {
	.buf_setup      = buffer_setup,
	.buf_prepare    = buffer_prepare,
	.buf_queue      = buffer_queue,
	.buf_release    = buffer_release,
};

/* ------------------------------------------------------------------
	IOCTL vidioc handling
   ------------------------------------------------------------------*/
static int vidioc_querycap(struct file *file, void  *priv,
					struct v4l2_capability *cap)
{
	strcpy(cap->driver, "vivi");
	strcpy(cap->card, "vivi");
	cap->version = VIVI_VERSION;
	cap->capabilities =	V4L2_CAP_VIDEO_CAPTURE |
				V4L2_CAP_STREAMING     |
				V4L2_CAP_READWRITE;
	return 0;
}

static int vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
					struct v4l2_fmtdesc *f)
{
	if (f->index > 0)
		return -EINVAL;

	strlcpy(f->description, format.name, sizeof(f->description));
	f->pixelformat = format.fourcc;
	return 0;
}

static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
					struct v4l2_format *f)
{
	struct vivi_fh *fh = priv;

	f->fmt.pix.width        = fh->width;
	f->fmt.pix.height       = fh->height;
	f->fmt.pix.field        = fh->vb_vidq.field;
	f->fmt.pix.pixelformat  = fh->fmt->fourcc;
	f->fmt.pix.bytesperline =
		(f->fmt.pix.width * fh->fmt->depth) >> 3;
	f->fmt.pix.sizeimage =
		f->fmt.pix.height * f->fmt.pix.bytesperline;

	return (0);
}

static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
			struct v4l2_format *f)
{
	struct vivi_fh  *fh  = priv;
	struct vivi_dev *dev = fh->dev;
	struct vivi_fmt *fmt;
	enum v4l2_field field;
	unsigned int maxw, maxh;

	if (format.fourcc != f->fmt.pix.pixelformat) {
		dprintk(dev, 1, "Fourcc format (0x%08x) invalid. "
			"Driver accepts only 0x%08x\n",
			f->fmt.pix.pixelformat, format.fourcc);
		return -EINVAL;
	}
	fmt = &format;

	field = f->fmt.pix.field;

	if (field == V4L2_FIELD_ANY) {
		field = V4L2_FIELD_INTERLACED;
	} else if (V4L2_FIELD_INTERLACED != field) {
		dprintk(dev, 1, "Field type invalid.\n");
		return -EINVAL;
	}

	maxw  = norm_maxw();
	maxh  = norm_maxh();

	f->fmt.pix.field = field;
	if (f->fmt.pix.height < 32)
		f->fmt.pix.height = 32;
	if (f->fmt.pix.height > maxh)
		f->fmt.pix.height = maxh;
	if (f->fmt.pix.width < 48)
		f->fmt.pix.width = 48;
	if (f->fmt.pix.width > maxw)
		f->fmt.pix.width = maxw;
	f->fmt.pix.width &= ~0x03;
	f->fmt.pix.bytesperline =
		(f->fmt.pix.width * fmt->depth) >> 3;
	f->fmt.pix.sizeimage =
		f->fmt.pix.height * f->fmt.pix.bytesperline;

	return 0;
}

/*FIXME: This seems to be generic enough to be at videodev2 */
static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
					struct v4l2_format *f)
{
	struct vivi_fh  *fh = priv;
	struct videobuf_queue *q = &fh->vb_vidq;

	int ret = vidioc_try_fmt_vid_cap(file, fh, f);
	if (ret < 0)
		return (ret);

	mutex_lock(&q->vb_lock);

	if (videobuf_queue_is_busy(&fh->vb_vidq)) {
		dprintk(fh->dev, 1, "%s queue busy\n", __func__);
		ret = -EBUSY;
		goto out;
	}

	fh->fmt           = &format;
	fh->width         = f->fmt.pix.width;
	fh->height        = f->fmt.pix.height;
	fh->vb_vidq.field = f->fmt.pix.field;
	fh->type          = f->type;

	ret = 0;
out:
	mutex_unlock(&q->vb_lock);

	return (ret);
}

static int vidioc_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p)
{
	struct vivi_fh  *fh = priv;

	return (videobuf_reqbufs(&fh->vb_vidq, p));
}

static int vidioc_querybuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct vivi_fh  *fh = priv;

	return (videobuf_querybuf(&fh->vb_vidq, p));
}

static int vidioc_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct vivi_fh *fh = priv;

	return (videobuf_qbuf(&fh->vb_vidq, p));
}

static int vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct vivi_fh  *fh = priv;

	return (videobuf_dqbuf(&fh->vb_vidq, p,
				file->f_flags & O_NONBLOCK));
}

#ifdef CONFIG_VIDEO_V4L1_COMPAT
static int vidiocgmbuf(struct file *file, void *priv, struct video_mbuf *mbuf)
{
	struct vivi_fh  *fh = priv;

	return videobuf_cgmbuf(&fh->vb_vidq, mbuf, 8);
}
#endif

static int vidioc_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct vivi_fh  *fh = priv;

	if (fh->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
		return -EINVAL;
	if (i != fh->type)
		return -EINVAL;

	return videobuf_streamon(&fh->vb_vidq);
}

static int vidioc_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct vivi_fh  *fh = priv;

	if (fh->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
		return -EINVAL;
	if (i != fh->type)
		return -EINVAL;

	return videobuf_streamoff(&fh->vb_vidq);
}

static int vidioc_s_std(struct file *file, void *priv, v4l2_std_id *i)
{
	return 0;
}

/* only one input in this sample driver */
static int vidioc_enum_input(struct file *file, void *priv,
				struct v4l2_input *inp)
{
	if (inp->index != 0)
		return -EINVAL;

	inp->type = V4L2_INPUT_TYPE_CAMERA;
	inp->std = V4L2_STD_525_60;
	strcpy(inp->name, "Camera");

	return (0);
}

static int vidioc_g_input(struct file *file, void *priv, unsigned int *i)
{
	*i = 0;

	return (0);
}
static int vidioc_s_input(struct file *file, void *priv, unsigned int i)
{
	if (i > 0)
		return -EINVAL;

	return (0);
}

	/* --- controls ---------------------------------------------- */
static int vidioc_queryctrl(struct file *file, void *priv,
			    struct v4l2_queryctrl *qc)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(vivi_qctrl); i++)
		if (qc->id && qc->id == vivi_qctrl[i].id) {
			memcpy(qc, &(vivi_qctrl[i]),
				sizeof(*qc));
			return (0);
		}

	return -EINVAL;
}

static int vidioc_g_ctrl(struct file *file, void *priv,
			 struct v4l2_control *ctrl)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(vivi_qctrl); i++)
		if (ctrl->id == vivi_qctrl[i].id) {
			ctrl->value = qctl_regs[i];
			return (0);
		}

	return -EINVAL;
}
static int vidioc_s_ctrl(struct file *file, void *priv,
				struct v4l2_control *ctrl)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(vivi_qctrl); i++)
		if (ctrl->id == vivi_qctrl[i].id) {
			if (ctrl->value < vivi_qctrl[i].minimum
			    || ctrl->value > vivi_qctrl[i].maximum) {
					return (-ERANGE);
				}
			qctl_regs[i] = ctrl->value;
			return (0);
		}
	return -EINVAL;
}

/* ------------------------------------------------------------------
	File operations for the device
   ------------------------------------------------------------------*/

#define line_buf_size(norm) (norm_maxw(norm)*(format.depth+7)/8)

static int vivi_open(struct inode *inode, struct file *file)
{
	int minor = iminor(inode);
	struct vivi_dev *dev;
	struct vivi_fh *fh = NULL;
	int i;
	int retval = 0;

	printk(KERN_DEBUG "vivi: open called (minor=%d)\n", minor);

	lock_kernel();
	list_for_each_entry(dev, &vivi_devlist, vivi_devlist)
		if (dev->vfd->minor == minor)
			goto found;
	unlock_kernel();
	return -ENODEV;

found:
	mutex_lock(&dev->mutex);
	dev->users++;

	if (dev->users > 1) {
		dev->users--;
		retval = -EBUSY;
		goto unlock;
	}

	dprintk(dev, 1, "open minor=%d type=%s users=%d\n", minor,
		v4l2_type_names[V4L2_BUF_TYPE_VIDEO_CAPTURE], dev->users);

	/* allocate + initialize per filehandle data */
	fh = kzalloc(sizeof(*fh), GFP_KERNEL);
	if (NULL == fh) {
		dev->users--;
		retval = -ENOMEM;
		goto unlock;
	}
unlock:
	mutex_unlock(&dev->mutex);
	if (retval) {
		unlock_kernel();
		return retval;
	}

	file->private_data = fh;
	fh->dev      = dev;

	fh->type     = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	fh->fmt      = &format;
	fh->width    = 640;
	fh->height   = 480;

	/* Put all controls at a sane state */
	for (i = 0; i < ARRAY_SIZE(vivi_qctrl); i++)
		qctl_regs[i] = vivi_qctrl[i].default_value;

	/* Resets frame counters */
	dev->h = 0;
	dev->m = 0;
	dev->s = 0;
	dev->ms = 0;
	dev->mv_count = 0;
	dev->jiffies = jiffies;
	sprintf(dev->timestr, "%02d:%02d:%02d:%03d",
			dev->h, dev->m, dev->s, dev->ms);

	videobuf_queue_vmalloc_init(&fh->vb_vidq, &vivi_video_qops,
			NULL, &dev->slock, fh->type, V4L2_FIELD_INTERLACED,
			sizeof(struct vivi_buffer), fh);

	vivi_start_thread(fh);
	unlock_kernel();

	return 0;
}

static ssize_t
vivi_read(struct file *file, char __user *data, size_t count, loff_t *ppos)
{
	struct vivi_fh *fh = file->private_data;

	if (fh->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
		return videobuf_read_stream(&fh->vb_vidq, data, count, ppos, 0,
					file->f_flags & O_NONBLOCK);
	}
	return 0;
}

static unsigned int
vivi_poll(struct file *file, struct poll_table_struct *wait)
{
	struct vivi_fh        *fh = file->private_data;
	struct vivi_dev       *dev = fh->dev;
	struct videobuf_queue *q = &fh->vb_vidq;

	dprintk(dev, 1, "%s\n", __func__);

	if (V4L2_BUF_TYPE_VIDEO_CAPTURE != fh->type)
		return POLLERR;

	return videobuf_poll_stream(file, q, wait);
}

static int vivi_close(struct inode *inode, struct file *file)
{
	struct vivi_fh         *fh = file->private_data;
	struct vivi_dev *dev       = fh->dev;
	struct vivi_dmaqueue *vidq = &dev->vidq;

	int minor = iminor(inode);

	vivi_stop_thread(vidq);
	videobuf_stop(&fh->vb_vidq);
	videobuf_mmap_free(&fh->vb_vidq);

	kfree(fh);

	mutex_lock(&dev->mutex);
	dev->users--;
	mutex_unlock(&dev->mutex);

	dprintk(dev, 1, "close called (minor=%d, users=%d)\n",
		minor, dev->users);

	return 0;
}

static int vivi_release(void)
{
	struct vivi_dev *dev;
	struct list_head *list;

	while (!list_empty(&vivi_devlist)) {
		list = vivi_devlist.next;
		list_del(list);
		dev = list_entry(list, struct vivi_dev, vivi_devlist);

		if (-1 != dev->vfd->minor) {
			printk(KERN_INFO "%s: unregistering /dev/video%d\n",
				VIVI_MODULE_NAME, dev->vfd->minor);
			video_unregister_device(dev->vfd);
		} else {
			printk(KERN_INFO "%s: releasing /dev/video%d\n",
				VIVI_MODULE_NAME, dev->vfd->minor);
			video_device_release(dev->vfd);
		}

		kfree(dev);
	}

	return 0;
}

static int vivi_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct vivi_fh  *fh = file->private_data;
	struct vivi_dev *dev = fh->dev;
	int ret;

	dprintk(dev, 1, "mmap called, vma=0x%08lx\n", (unsigned long)vma);

	ret = videobuf_mmap_mapper(&fh->vb_vidq, vma);

	dprintk(dev, 1, "vma start=0x%08lx, size=%ld, ret=%d\n",
		(unsigned long)vma->vm_start,
		(unsigned long)vma->vm_end-(unsigned long)vma->vm_start,
		ret);

	return ret;
}

static const struct file_operations vivi_fops = {
	.owner		= THIS_MODULE,
	.open           = vivi_open,
	.release        = vivi_close,
	.read           = vivi_read,
	.poll		= vivi_poll,
	.ioctl          = video_ioctl2, /* V4L2 ioctl handler */
	.compat_ioctl   = v4l_compat_ioctl32,
	.mmap           = vivi_mmap,
	.llseek         = no_llseek,
};

static const struct v4l2_ioctl_ops vivi_ioctl_ops = {
	.vidioc_querycap      = vidioc_querycap,
	.vidioc_enum_fmt_vid_cap  = vidioc_enum_fmt_vid_cap,
	.vidioc_g_fmt_vid_cap     = vidioc_g_fmt_vid_cap,
	.vidioc_try_fmt_vid_cap   = vidioc_try_fmt_vid_cap,
	.vidioc_s_fmt_vid_cap     = vidioc_s_fmt_vid_cap,
	.vidioc_reqbufs       = vidioc_reqbufs,
	.vidioc_querybuf      = vidioc_querybuf,
	.vidioc_qbuf          = vidioc_qbuf,
	.vidioc_dqbuf         = vidioc_dqbuf,
	.vidioc_s_std         = vidioc_s_std,
	.vidioc_enum_input    = vidioc_enum_input,
	.vidioc_g_input       = vidioc_g_input,
	.vidioc_s_input       = vidioc_s_input,
	.vidioc_queryctrl     = vidioc_queryctrl,
	.vidioc_g_ctrl        = vidioc_g_ctrl,
	.vidioc_s_ctrl        = vidioc_s_ctrl,
	.vidioc_streamon      = vidioc_streamon,
	.vidioc_streamoff     = vidioc_streamoff,
#ifdef CONFIG_VIDEO_V4L1_COMPAT
	.vidiocgmbuf          = vidiocgmbuf,
#endif
};

static struct video_device vivi_template = {
	.name		= "vivi",
	.fops           = &vivi_fops,
	.ioctl_ops 	= &vivi_ioctl_ops,
	.minor		= -1,
	.release	= video_device_release,

	.tvnorms              = V4L2_STD_525_60,
	.current_norm         = V4L2_STD_NTSC_M,
};
/* -----------------------------------------------------------------
	Initialization and module stuff
   ------------------------------------------------------------------*/

/* This routine allocates from 1 to n_devs virtual drivers.

   The real maximum number of virtual drivers will depend on how many drivers
   will succeed. This is limited to the maximum number of devices that
   videodev supports. Since there are 64 minors for video grabbers, this is
   currently the theoretical maximum limit. However, a further limit does
   exist at videodev that forbids any driver to register more than 32 video
   grabbers.
 */
static int __init vivi_init(void)
{
	int ret = -ENOMEM, i;
	struct vivi_dev *dev;
	struct video_device *vfd;

	if (n_devs <= 0)
		n_devs = 1;

	for (i = 0; i < n_devs; i++) {
		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
		if (!dev)
			break;

		/* init video dma queues */
		INIT_LIST_HEAD(&dev->vidq.active);
		init_waitqueue_head(&dev->vidq.wq);

		/* initialize locks */
		spin_lock_init(&dev->slock);
		mutex_init(&dev->mutex);

		vfd = video_device_alloc();
		if (!vfd) {
			kfree(dev);
			break;
		}

		*vfd = vivi_template;

		ret = video_register_device(vfd, VFL_TYPE_GRABBER, video_nr);
		if (ret < 0) {
			video_device_release(vfd);
			kfree(dev);

			/* If some registers succeeded, keep driver */
			if (i)
				ret = 0;

			break;
		}

		/* Now that everything is fine, let's add it to device list */
		list_add_tail(&dev->vivi_devlist, &vivi_devlist);

		snprintf(vfd->name, sizeof(vfd->name), "%s (%i)",
			 vivi_template.name, vfd->minor);

		if (video_nr >= 0)
			video_nr++;

		dev->vfd = vfd;
		printk(KERN_INFO "%s: V4L2 device registered as /dev/video%d\n",
			VIVI_MODULE_NAME, vfd->minor);
	}

	if (ret < 0) {
		vivi_release();
		printk(KERN_INFO "Error %d while loading vivi driver\n", ret);
	} else {
		printk(KERN_INFO "Video Technology Magazine Virtual Video "
			"Capture Board ver %u.%u.%u successfully loaded.\n",
			(VIVI_VERSION >> 16) & 0xFF, (VIVI_VERSION >> 8) & 0xFF,
			VIVI_VERSION & 0xFF);

		/* n_devs will reflect the actual number of allocated devices */
		n_devs = i;
	}

	return ret;
}

static void __exit vivi_exit(void)
{
	vivi_release();
}

module_init(vivi_init);
module_exit(vivi_exit);

MODULE_DESCRIPTION("Video Technology Magazine Virtual Video Capture Board");
MODULE_AUTHOR("Mauro Carvalho Chehab, Ted Walther and John Sokol");
MODULE_LICENSE("Dual BSD/GPL");

module_param(video_nr, uint, 0444);
MODULE_PARM_DESC(video_nr, "video iminor start number");

module_param(n_devs, uint, 0444);
MODULE_PARM_DESC(n_devs, "number of video devices to create");

module_param_named(debug, vivi_template.debug, int, 0444);
MODULE_PARM_DESC(debug, "activates debug info");

module_param(vid_limit, int, 0644);
MODULE_PARM_DESC(vid_limit, "capture memory limit in megabytes");