usbtv.c

/*
 * Fushicai USBTV007 Video Grabber Driver
 *
 * Product web site:
 * http://www.fushicai.com/products_detail/&productId=d05449ee-b690-42f9-a661-aa7353894bed.html
 *
 * Following LWN articles were very useful in construction of this driver:
 * Video4Linux2 API series: http://lwn.net/Articles/203924/
 * videobuf2 API explanation: http://lwn.net/Articles/447435/
 * Thanks go to Jonathan Corbet for providing this quality documentation.
 * He is awesome.
 *
 * Copyright (c) 2013 Lubomir Rintel
 * All rights reserved.
 * No physical hardware was harmed running Windows during the
 * reverse-engineering activity
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 */

#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/videodev2.h>

#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-vmalloc.h>

/* Hardware. */
#define USBTV_VIDEO_ENDP	0x81
#define USBTV_BASE		0xc000
#define USBTV_REQUEST_REG	12

/* Number of concurrent isochronous urbs submitted.
 * Higher numbers was seen to overly saturate the USB bus. */
#define USBTV_ISOC_TRANSFERS	16
#define USBTV_ISOC_PACKETS	8

#define USBTV_CHUNK_SIZE	256
#define USBTV_CHUNK		240

/* Chunk header. */
#define USBTV_MAGIC_OK(chunk)	((be32_to_cpu(chunk[0]) & 0xff000000) \
							== 0x88000000)
#define USBTV_FRAME_ID(chunk)	((be32_to_cpu(chunk[0]) & 0x00ff0000) >> 16)
#define USBTV_ODD(chunk)	((be32_to_cpu(chunk[0]) & 0x0000f000) >> 15)
#define USBTV_CHUNK_NO(chunk)	(be32_to_cpu(chunk[0]) & 0x00000fff)

#define USBTV_TV_STD  (V4L2_STD_525_60 | V4L2_STD_PAL)

/* parameters for supported TV norms */
struct usbtv_norm_params {
	v4l2_std_id norm;
	int cap_width, cap_height;
};

static struct usbtv_norm_params norm_params[] = {
	{
		.norm = V4L2_STD_525_60,
		.cap_width = 720,
		.cap_height = 480,
	},
	{
		.norm = V4L2_STD_PAL,
		.cap_width = 720,
		.cap_height = 576,
	}
};

/* A single videobuf2 frame buffer. */
struct usbtv_buf {
	struct vb2_buffer vb;
	struct list_head list;
};

/* Per-device structure. */
struct usbtv {
	struct device *dev;
	struct usb_device *udev;
	struct v4l2_device v4l2_dev;
	struct video_device vdev;
	struct vb2_queue vb2q;
	struct v4l2_fh *owner;
	struct mutex v4l2_lock;
	struct mutex vb2q_lock;

	/* List of videobuf2 buffers protected by a lock. */
	spinlock_t buflock;
	struct list_head bufs;

	/* Number of currently processed frame, useful find
	 * out when a new one begins. */
	u32 frame_id;
	int chunks_done;

	enum {
		USBTV_COMPOSITE_INPUT,
		USBTV_SVIDEO_INPUT,
	} input;
	v4l2_std_id norm;
	int width, height;
	int n_chunks;
	int iso_size;
	unsigned int sequence;
	struct urb *isoc_urbs[USBTV_ISOC_TRANSFERS];
};

/*
 * Include helper functions found in newer kernels
 */
/*
 * The following functions are not part of the vb2 core API, but are helper
 * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations
 * and struct vb2_ops.
 * They contain boilerplate code that most if not all drivers have to do
 * and so they simplify the driver code.
 */


/* vb2 ioctl helpers */

int vb2_ioctl_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p)
{
	struct usbtv *usbtv = video_drvdata(file);

	return vb2_reqbufs(&usbtv->vb2q, p);
}

int vb2_ioctl_create_bufs(struct file *file, void *priv,
			  struct v4l2_create_buffers *p)
{
	struct usbtv *usbtv = video_drvdata(file);
	int res;

	res = vb2_create_bufs(&usbtv->vb2q, p);
	if (res == 0)
		usbtv->owner = file->private_data;
	return res;
}

int vb2_ioctl_prepare_buf(struct file *file, void *priv,
			  struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_prepare_buf(&usbtv->vb2q, p);
}

int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_querybuf(&usbtv->vb2q, p);
}

int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_qbuf(&usbtv->vb2q, p);
}

int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_dqbuf(&usbtv->vb2q, p, file->f_flags & O_NONBLOCK);
}

int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_streamon(&usbtv->vb2q, i);
}

int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_streamoff(&usbtv->vb2q, i);
}

/* v4l2_file_operations helpers */

int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	return vb2_mmap(&usbtv->vb2q, vma);
}

int vb2_fop_release(struct file *file)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);

	if (file->private_data == usbtv->owner) {
		vb2_queue_release(&usbtv->vb2q);
		usbtv->owner = NULL;
	}
	return v4l2_fh_release(file);
}

ssize_t vb2_fop_write(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);
	struct mutex *lock = &usbtv->vb2q_lock ? &usbtv->vb2q_lock : vdev->lock;
	bool must_lock = lock;
	int err = -EBUSY;

	if (must_lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	err = vb2_write(&usbtv->vb2q, buf, count, ppos,
		       file->f_flags & O_NONBLOCK);
	if (err >= 0)
		usbtv->owner = file->private_data;
	if (must_lock)
		mutex_unlock(lock);
	return err;
}

ssize_t vb2_fop_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);
	struct mutex *lock = &usbtv->vb2q_lock ? &usbtv->vb2q_lock : vdev->lock;
	bool must_lock = vdev->lock;
	int err = -EBUSY;

	if (must_lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	err = vb2_read(&usbtv->vb2q, buf, count, ppos,
		       file->f_flags & O_NONBLOCK);
	if (err >= 0)
		usbtv->owner = file->private_data;
	if (must_lock)
		mutex_unlock(lock);
	return err;
}

unsigned int vb2_fop_poll(struct file *file, poll_table *wait)
{
	struct video_device *vdev = video_devdata(file);
	struct usbtv *usbtv = container_of(vdev, struct usbtv, vdev);
	struct vb2_queue *q = &usbtv->vb2q;
	struct mutex *lock = &usbtv->vb2q_lock ? &usbtv->vb2q_lock : vdev->lock;
	unsigned res;
	void *fileio;
	/* Yuck. We really need to get rid of this flag asap. If it is
	   set, then the core took the serialization lock before calling
	   poll(). This is being phased out, but for now we have to handle
	   this case. */
	bool must_lock = false;

	/* Try to be smart: only lock if polling might start fileio,
	   otherwise locking will only introduce unwanted delays. */
	if (q->num_buffers == 0 && q->fileio == NULL) {
		if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) &&
				(POLLIN | POLLRDNORM))
			must_lock = true;
		else if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) &&
				(POLLOUT | POLLWRNORM))
			must_lock = true;
	}

	/* If locking is needed, but this helper doesn't know how, then you
	   shouldn't be using this helper but you should write your own. */
	WARN_ON(must_lock && !lock);

	if (must_lock && lock && mutex_lock_interruptible(lock))
		return POLLERR;

	fileio = q->fileio;

	res = vb2_poll(&usbtv->vb2q, file, wait);

	/* If fileio was started, then we have a new queue owner. */
	if (must_lock && !fileio && q->fileio)
		usbtv->owner = file->private_data;
	if (must_lock && lock)
		mutex_unlock(lock);
	return res;
}


static int usbtv_configure_for_norm(struct usbtv *usbtv, v4l2_std_id norm)
{
	int i, ret = 0;
	struct usbtv_norm_params *params = NULL;

	for (i = 0; i < ARRAY_SIZE(norm_params); i++) {
		if (norm_params[i].norm & norm) {
			params = &norm_params[i];
			break;
		}
	}

	if (params) {
		usbtv->width = params->cap_width;
		usbtv->height = params->cap_height;
		usbtv->n_chunks = usbtv->width * usbtv->height
						/ 4 / USBTV_CHUNK;
		usbtv->norm = params->norm;
	} else
		ret = -EINVAL;

	return ret;
}

static int usbtv_set_regs(struct usbtv *usbtv, const u16 regs[][2], int size)
{
	int ret;
	int pipe = usb_rcvctrlpipe(usbtv->udev, 0);
	int i;

	for (i = 0; i < size; i++) {
		u16 index = regs[i][0];
		u16 value = regs[i][1];

		ret = usb_control_msg(usbtv->udev, pipe, USBTV_REQUEST_REG,
			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			value, index, NULL, 0, 0);
		if (ret < 0)
			return ret;
	}

	return 0;
}

static int usbtv_select_input(struct usbtv *usbtv, int input)
{
	int ret;

	static const u16 composite[][2] = {
		{ USBTV_BASE + 0x0105, 0x0060 },
		{ USBTV_BASE + 0x011f, 0x00f2 },
		{ USBTV_BASE + 0x0127, 0x0060 },
		{ USBTV_BASE + 0x00ae, 0x0010 },
		{ USBTV_BASE + 0x0284, 0x00aa },
		{ USBTV_BASE + 0x0239, 0x0060 },
	};

	static const u16 svideo[][2] = {
		{ USBTV_BASE + 0x0105, 0x0010 },
		{ USBTV_BASE + 0x011f, 0x00ff },
		{ USBTV_BASE + 0x0127, 0x0060 },
		{ USBTV_BASE + 0x00ae, 0x0030 },
		{ USBTV_BASE + 0x0284, 0x0088 },
		{ USBTV_BASE + 0x0239, 0x0060 },
	};

	switch (input) {
	case USBTV_COMPOSITE_INPUT:
		ret = usbtv_set_regs(usbtv, composite, ARRAY_SIZE(composite));
		break;
	case USBTV_SVIDEO_INPUT:
		ret = usbtv_set_regs(usbtv, svideo, ARRAY_SIZE(svideo));
		break;
	default:
		ret = -EINVAL;
	}

	if (!ret)
		usbtv->input = input;

	return ret;
}

static int usbtv_select_norm(struct usbtv *usbtv, v4l2_std_id norm)
{
	int ret;
	static const u16 pal[][2] = {
		{ USBTV_BASE + 0x001a, 0x0068 },
		{ USBTV_BASE + 0x010e, 0x0072 },
		{ USBTV_BASE + 0x010f, 0x00a2 },
		{ USBTV_BASE + 0x0112, 0x00b0 },
		{ USBTV_BASE + 0x0117, 0x0001 },
		{ USBTV_BASE + 0x0118, 0x002c },
		{ USBTV_BASE + 0x012d, 0x0010 },
		{ USBTV_BASE + 0x012f, 0x0020 },
		{ USBTV_BASE + 0x024f, 0x0002 },
		{ USBTV_BASE + 0x0254, 0x0059 },
		{ USBTV_BASE + 0x025a, 0x0016 },
		{ USBTV_BASE + 0x025b, 0x0035 },
		{ USBTV_BASE + 0x0263, 0x0017 },
		{ USBTV_BASE + 0x0266, 0x0016 },
		{ USBTV_BASE + 0x0267, 0x0036 }
	};

	static const u16 ntsc[][2] = {
		{ USBTV_BASE + 0x001a, 0x0079 },
		{ USBTV_BASE + 0x010e, 0x0068 },
		{ USBTV_BASE + 0x010f, 0x009c },
		{ USBTV_BASE + 0x0112, 0x00f0 },
		{ USBTV_BASE + 0x0117, 0x0000 },
		{ USBTV_BASE + 0x0118, 0x00fc },
		{ USBTV_BASE + 0x012d, 0x0004 },
		{ USBTV_BASE + 0x012f, 0x0008 },
		{ USBTV_BASE + 0x024f, 0x0001 },
		{ USBTV_BASE + 0x0254, 0x005f },
		{ USBTV_BASE + 0x025a, 0x0012 },
		{ USBTV_BASE + 0x025b, 0x0001 },
		{ USBTV_BASE + 0x0263, 0x001c },
		{ USBTV_BASE + 0x0266, 0x0011 },
		{ USBTV_BASE + 0x0267, 0x0005 }
	};

	ret = usbtv_configure_for_norm(usbtv, norm);

	if (!ret) {
		if (norm & V4L2_STD_525_60)
			ret = usbtv_set_regs(usbtv, ntsc, ARRAY_SIZE(ntsc));
		else if (norm & V4L2_STD_PAL)
			ret = usbtv_set_regs(usbtv, pal, ARRAY_SIZE(pal));
	}

	return ret;
}

static int usbtv_setup_capture(struct usbtv *usbtv)
{
	int ret;
	static const u16 setup[][2] = {
		/* These seem to enable the device. */
		{ USBTV_BASE + 0x0008, 0x0001 },
		{ USBTV_BASE + 0x01d0, 0x00ff },
		{ USBTV_BASE + 0x01d9, 0x0002 },

		/* These seem to influence color parameters, such as
		 * brightness, etc. */
		{ USBTV_BASE + 0x0239, 0x0040 },
		{ USBTV_BASE + 0x0240, 0x0000 },
		{ USBTV_BASE + 0x0241, 0x0000 },
		{ USBTV_BASE + 0x0242, 0x0002 },
		{ USBTV_BASE + 0x0243, 0x0080 },
		{ USBTV_BASE + 0x0244, 0x0012 },
		{ USBTV_BASE + 0x0245, 0x0090 },
		{ USBTV_BASE + 0x0246, 0x0000 },

		{ USBTV_BASE + 0x0278, 0x002d },
		{ USBTV_BASE + 0x0279, 0x000a },
		{ USBTV_BASE + 0x027a, 0x0032 },
		{ 0xf890, 0x000c },
		{ 0xf894, 0x0086 },

		{ USBTV_BASE + 0x00ac, 0x00c0 },
		{ USBTV_BASE + 0x00ad, 0x0000 },
		{ USBTV_BASE + 0x00a2, 0x0012 },
		{ USBTV_BASE + 0x00a3, 0x00e0 },
		{ USBTV_BASE + 0x00a4, 0x0028 },
		{ USBTV_BASE + 0x00a5, 0x0082 },
		{ USBTV_BASE + 0x00a7, 0x0080 },
		{ USBTV_BASE + 0x0000, 0x0014 },
		{ USBTV_BASE + 0x0006, 0x0003 },
		{ USBTV_BASE + 0x0090, 0x0099 },
		{ USBTV_BASE + 0x0091, 0x0090 },
		{ USBTV_BASE + 0x0094, 0x0068 },
		{ USBTV_BASE + 0x0095, 0x0070 },
		{ USBTV_BASE + 0x009c, 0x0030 },
		{ USBTV_BASE + 0x009d, 0x00c0 },
		{ USBTV_BASE + 0x009e, 0x00e0 },
		{ USBTV_BASE + 0x0019, 0x0006 },
		{ USBTV_BASE + 0x008c, 0x00ba },
		{ USBTV_BASE + 0x0101, 0x00ff },
		{ USBTV_BASE + 0x010c, 0x00b3 },
		{ USBTV_BASE + 0x01b2, 0x0080 },
		{ USBTV_BASE + 0x01b4, 0x00a0 },
		{ USBTV_BASE + 0x014c, 0x00ff },
		{ USBTV_BASE + 0x014d, 0x00ca },
		{ USBTV_BASE + 0x0113, 0x0053 },
		{ USBTV_BASE + 0x0119, 0x008a },
		{ USBTV_BASE + 0x013c, 0x0003 },
		{ USBTV_BASE + 0x0150, 0x009c },
		{ USBTV_BASE + 0x0151, 0x0071 },
		{ USBTV_BASE + 0x0152, 0x00c6 },
		{ USBTV_BASE + 0x0153, 0x0084 },
		{ USBTV_BASE + 0x0154, 0x00bc },
		{ USBTV_BASE + 0x0155, 0x00a0 },
		{ USBTV_BASE + 0x0156, 0x00a0 },
		{ USBTV_BASE + 0x0157, 0x009c },
		{ USBTV_BASE + 0x0158, 0x001f },
		{ USBTV_BASE + 0x0159, 0x0006 },
		{ USBTV_BASE + 0x015d, 0x0000 },

		{ USBTV_BASE + 0x0284, 0x0088 },
		{ USBTV_BASE + 0x0003, 0x0004 },
		{ USBTV_BASE + 0x0100, 0x00d3 },
		{ USBTV_BASE + 0x0115, 0x0015 },
		{ USBTV_BASE + 0x0220, 0x002e },
		{ USBTV_BASE + 0x0225, 0x0008 },
		{ USBTV_BASE + 0x024e, 0x0002 },
		{ USBTV_BASE + 0x024e, 0x0002 },
		{ USBTV_BASE + 0x024f, 0x0002 },
	};

	ret = usbtv_set_regs(usbtv, setup, ARRAY_SIZE(setup));
	if (ret)
		return ret;

	ret = usbtv_select_norm(usbtv, usbtv->norm);
	if (ret)
		return ret;

	ret = usbtv_select_input(usbtv, usbtv->input);
	if (ret)
		return ret;

	return 0;
}

/* Copy data from chunk into a frame buffer, deinterlacing the data
 * into every second line. Unfortunately, they don't align nicely into
 * 720 pixel lines, as the chunk is 240 words long, which is 480 pixels.
 * Therefore, we break down the chunk into two halves before copyting,
 * so that we can interleave a line if needed. */
static void usbtv_chunk_to_vbuf(u32 *frame, u32 *src, int chunk_no, int odd)
{
	int half;

	for (half = 0; half < 2; half++) {
		int part_no = chunk_no * 2 + half;
		int line = part_no / 3;
		int part_index = (line * 2 + !odd) * 3 + (part_no % 3);

		u32 *dst = &frame[part_index * USBTV_CHUNK/2];
		memcpy(dst, src, USBTV_CHUNK/2 * sizeof(*src));
		src += USBTV_CHUNK/2;
	}
}

void v4l2_get_timestamp(struct timeval *tv)
{
	struct timespec ts;

	ktime_get_ts(&ts);
	tv->tv_sec = ts.tv_sec;
	tv->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
}

/* Called for each 256-byte image chunk.
 * First word identifies the chunk, followed by 240 words of image
 * data and padding. */
static void usbtv_image_chunk(struct usbtv *usbtv, u32 *chunk)
{
	int frame_id, odd, chunk_no;
	u32 *frame;
	struct usbtv_buf *buf;
	unsigned long flags;

	/* Ignore corrupted lines. */
	if (!USBTV_MAGIC_OK(chunk))
		return;
	frame_id = USBTV_FRAME_ID(chunk);
	odd = USBTV_ODD(chunk);
	chunk_no = USBTV_CHUNK_NO(chunk);
	if (chunk_no >= usbtv->n_chunks)
		return;

	/* Beginning of a frame. */
	if (chunk_no == 0) {
		usbtv->frame_id = frame_id;
		usbtv->chunks_done = 0;
	}

	if (usbtv->frame_id != frame_id)
		return;

	spin_lock_irqsave(&usbtv->buflock, flags);
	if (list_empty(&usbtv->bufs)) {
		/* No free buffers. Userspace likely too slow. */
		spin_unlock_irqrestore(&usbtv->buflock, flags);
		return;
	}

	/* First available buffer. */
	buf = list_first_entry(&usbtv->bufs, struct usbtv_buf, list);
	frame = vb2_plane_vaddr(&buf->vb, 0);

	/* Copy the chunk data. */
	usbtv_chunk_to_vbuf(frame, &chunk[1], chunk_no, odd);
	usbtv->chunks_done++;

	/* Last chunk in a frame, signalling an end */
	if (odd && chunk_no == usbtv->n_chunks-1) {
		int size = vb2_plane_size(&buf->vb, 0);
		enum vb2_buffer_state state = usbtv->chunks_done ==
						usbtv->n_chunks ?
						VB2_BUF_STATE_DONE :
						VB2_BUF_STATE_ERROR;

		buf->vb.v4l2_buf.field = V4L2_FIELD_INTERLACED;
		buf->vb.v4l2_buf.sequence = usbtv->sequence++;
		v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
		vb2_set_plane_payload(&buf->vb, 0, size);
		vb2_buffer_done(&buf->vb, state);
		list_del(&buf->list);
	}

	spin_unlock_irqrestore(&usbtv->buflock, flags);
}

/* Got image data. Each packet contains a number of 256-word chunks we
 * compose the image from. */
static void usbtv_iso_cb(struct urb *ip)
{
	int ret;
	int i;
	struct usbtv *usbtv = (struct usbtv *)ip->context;

	switch (ip->status) {
	/* All fine. */
	case 0:
		break;
	/* Device disconnected or capture stopped? */
	case -ENODEV:
	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
		return;
	/* Unknown error. Retry. */
	default:
		dev_warn(usbtv->dev, "Bad response for ISO request.\n");
		goto resubmit;
	}

	for (i = 0; i < ip->number_of_packets; i++) {
		int size = ip->iso_frame_desc[i].actual_length;
		unsigned char *data = ip->transfer_buffer +
				ip->iso_frame_desc[i].offset;
		int offset;

		for (offset = 0; USBTV_CHUNK_SIZE * offset < size; offset++)
			usbtv_image_chunk(usbtv,
				(u32 *)&data[USBTV_CHUNK_SIZE * offset]);
	}

resubmit:
	ret = usb_submit_urb(ip, GFP_ATOMIC);
	if (ret < 0)
		dev_warn(usbtv->dev, "Could not resubmit ISO URB\n");
}

static struct urb *usbtv_setup_iso_transfer(struct usbtv *usbtv)
{
	struct urb *ip;
	int size = usbtv->iso_size;
	int i;

	ip = usb_alloc_urb(USBTV_ISOC_PACKETS, GFP_KERNEL);
	if (ip == NULL)
		return NULL;

	ip->dev = usbtv->udev;
	ip->context = usbtv;
	ip->pipe = usb_rcvisocpipe(usbtv->udev, USBTV_VIDEO_ENDP);
	ip->interval = 1;
	ip->transfer_flags = URB_ISO_ASAP;
	ip->transfer_buffer = kzalloc(size * USBTV_ISOC_PACKETS,
						GFP_KERNEL);
	ip->complete = usbtv_iso_cb;
	ip->number_of_packets = USBTV_ISOC_PACKETS;
	ip->transfer_buffer_length = size * USBTV_ISOC_PACKETS;
	for (i = 0; i < USBTV_ISOC_PACKETS; i++) {
		ip->iso_frame_desc[i].offset = size * i;
		ip->iso_frame_desc[i].length = size;
	}

	return ip;
}

static void usbtv_stop(struct usbtv *usbtv)
{
	int i;
	unsigned long flags;

	/* Cancel running transfers. */
	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
		struct urb *ip = usbtv->isoc_urbs[i];
		if (ip == NULL)
			continue;
		usb_kill_urb(ip);
		kfree(ip->transfer_buffer);
		usb_free_urb(ip);
		usbtv->isoc_urbs[i] = NULL;
	}

	/* Return buffers to userspace. */
	spin_lock_irqsave(&usbtv->buflock, flags);
	while (!list_empty(&usbtv->bufs)) {
		struct usbtv_buf *buf = list_first_entry(&usbtv->bufs,
						struct usbtv_buf, list);
		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
		list_del(&buf->list);
	}
	spin_unlock_irqrestore(&usbtv->buflock, flags);
}

static int usbtv_start(struct usbtv *usbtv)
{
	int i;
	int ret;

	ret = usb_set_interface(usbtv->udev, 0, 0);
	if (ret < 0)
		return ret;

	ret = usbtv_setup_capture(usbtv);
	if (ret < 0)
		return ret;

	ret = usb_set_interface(usbtv->udev, 0, 1);
	if (ret < 0)
		return ret;

	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
		struct urb *ip;

		ip = usbtv_setup_iso_transfer(usbtv);
		if (ip == NULL) {
			ret = -ENOMEM;
			goto start_fail;
		}
		usbtv->isoc_urbs[i] = ip;

		ret = usb_submit_urb(ip, GFP_KERNEL);
		if (ret < 0)
			goto start_fail;
	}

	return 0;

start_fail:
	usbtv_stop(usbtv);
	return ret;
}

struct usb_device_id usbtv_id_table[] = {
	{ USB_DEVICE(0x1b71, 0x3002) },
	{}
};
MODULE_DEVICE_TABLE(usb, usbtv_id_table);

static int usbtv_querycap(struct file *file, void *priv,
				struct v4l2_capability *cap)
{
	struct usbtv *dev = video_drvdata(file);

	strlcpy(cap->driver, "usbtv", sizeof(cap->driver));
	strlcpy(cap->card, "usbtv", sizeof(cap->card));
	usb_make_path(dev->udev, cap->bus_info, sizeof(cap->bus_info));
	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE;
	cap->capabilities |= V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
	return 0;
}

static int usbtv_enum_input(struct file *file, void *priv,
					struct v4l2_input *i)
{
	struct usbtv *dev = video_drvdata(file);

	switch (i->index) {
	case USBTV_COMPOSITE_INPUT:
		strlcpy(i->name, "Composite", sizeof(i->name));
		break;
	case USBTV_SVIDEO_INPUT:
		strlcpy(i->name, "S-Video", sizeof(i->name));
		break;
	default:
		return -EINVAL;
	}

	i->type = V4L2_INPUT_TYPE_CAMERA;
	i->std = dev->vdev.tvnorms;
	return 0;
}

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

	strlcpy(f->description, "16 bpp YUY2, 4:2:2, packed",
					sizeof(f->description));
	f->pixelformat = V4L2_PIX_FMT_YUYV;
	return 0;
}

static int usbtv_fmt_vid_cap(struct file *file, void *priv,
					struct v4l2_format *f)
{
	struct usbtv *usbtv = video_drvdata(file);

	f->fmt.pix.width = usbtv->width;
	f->fmt.pix.height = usbtv->height;
	f->fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
	f->fmt.pix.bytesperline = usbtv->width * 2;
	f->fmt.pix.sizeimage = (f->fmt.pix.bytesperline * f->fmt.pix.height);
	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;

	return 0;
}

static int usbtv_g_std(struct file *file, void *priv, v4l2_std_id *norm)
{
	struct usbtv *usbtv = video_drvdata(file);
	*norm = usbtv->norm;
	return 0;
}

static int usbtv_s_std(struct file *file, void *priv, v4l2_std_id norm)
{
	int ret = -EINVAL;
	struct usbtv *usbtv = video_drvdata(file);

	if ((norm & V4L2_STD_525_60) || (norm & V4L2_STD_PAL))
		ret = usbtv_select_norm(usbtv, norm);

	return ret;
}

static int usbtv_g_input(struct file *file, void *priv, unsigned int *i)
{
	struct usbtv *usbtv = video_drvdata(file);
	*i = usbtv->input;
	return 0;
}

static int usbtv_s_input(struct file *file, void *priv, unsigned int i)
{
	struct usbtv *usbtv = video_drvdata(file);
	return usbtv_select_input(usbtv, i);
}

struct v4l2_ioctl_ops usbtv_ioctl_ops = {
	.vidioc_querycap = usbtv_querycap,
	.vidioc_enum_input = usbtv_enum_input,
	.vidioc_enum_fmt_vid_cap = usbtv_enum_fmt_vid_cap,
	.vidioc_g_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_try_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_s_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_g_std = usbtv_g_std,
	.vidioc_s_std = usbtv_s_std,
	.vidioc_g_input = usbtv_g_input,
	.vidioc_s_input = usbtv_s_input,

	.vidioc_reqbufs = vb2_ioctl_reqbufs,
	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
	.vidioc_querybuf = vb2_ioctl_querybuf,
	.vidioc_create_bufs = vb2_ioctl_create_bufs,
	.vidioc_qbuf = vb2_ioctl_qbuf,
	.vidioc_dqbuf = vb2_ioctl_dqbuf,
	.vidioc_streamon = vb2_ioctl_streamon,
	.vidioc_streamoff = vb2_ioctl_streamoff,
};

struct v4l2_file_operations usbtv_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = video_ioctl2,
	.mmap = vb2_fop_mmap,
	.open = v4l2_fh_open,
	.release = vb2_fop_release,
	.read = vb2_fop_read,
	.poll = vb2_fop_poll,
};

static int usbtv_queue_setup(struct vb2_queue *vq,
	const struct v4l2_format *v4l_fmt, unsigned int *nbuffers,
	unsigned int *nplanes, unsigned int sizes[], void *alloc_ctxs[])
{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);

	if (*nbuffers < 2)
		*nbuffers = 2;
	*nplanes = 1;
	sizes[0] = USBTV_CHUNK * usbtv->n_chunks * 2 * sizeof(u32);

	return 0;
}

static void usbtv_buf_queue(struct vb2_buffer *vb)
{
	struct usbtv *usbtv = vb2_get_drv_priv(vb->vb2_queue);
	struct usbtv_buf *buf = container_of(vb, struct usbtv_buf, vb);
	unsigned long flags;

	if (usbtv->udev == NULL) {
		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
		return;
	}

	spin_lock_irqsave(&usbtv->buflock, flags);
	list_add_tail(&buf->list, &usbtv->bufs);
	spin_unlock_irqrestore(&usbtv->buflock, flags);
}

static int usbtv_start_streaming(struct vb2_queue *vq, unsigned int count)
{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);

	if (usbtv->udev == NULL)
		return -ENODEV;

	return usbtv_start(usbtv);
}

static int usbtv_stop_streaming(struct vb2_queue *vq)
{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);

	if (usbtv->udev == NULL)
		return -ENODEV;

	usbtv_stop(usbtv);
	return 0;
}

struct vb2_ops usbtv_vb2_ops = {
	.queue_setup = usbtv_queue_setup,
	.buf_queue = usbtv_buf_queue,
	.start_streaming = usbtv_start_streaming,
	.stop_streaming = usbtv_stop_streaming,
};

static void usbtv_release(struct v4l2_device *v4l2_dev)
{
	struct usbtv *usbtv = container_of(v4l2_dev, struct usbtv, v4l2_dev);

	v4l2_device_unregister(&usbtv->v4l2_dev);
	vb2_queue_release(&usbtv->vb2q);
	kfree(usbtv);
}

static int usbtv_probe(struct usb_interface *intf,
	const struct usb_device_id *id)
{
	int ret;
	int size;
	struct device *dev = &intf->dev;
	struct usbtv *usbtv;

	printk("Probe routine\n");

	/* Checks that the device is what we think it is. */
	if (intf->num_altsetting != 2)
		return -ENODEV;
	if (intf->altsetting[1].desc.bNumEndpoints != 4)
		return -ENODEV;

	/* Packet size is split into 11 bits of base size and count of
	 * extra multiplies of it.*/
	size = usb_endpoint_maxp(&intf->altsetting[1].endpoint[0].desc);
	size = (size & 0x07ff) * (((size & 0x1800) >> 11) + 1);

	/* Device structure */
	usbtv = kzalloc(sizeof(struct usbtv), GFP_KERNEL);
	if (usbtv == NULL)
		return -ENOMEM;
	usbtv->dev = dev;
	usbtv->udev = usb_get_dev(interface_to_usbdev(intf));

	usbtv->iso_size = size;

	(void)usbtv_configure_for_norm(usbtv, V4L2_STD_525_60);

	spin_lock_init(&usbtv->buflock);
	mutex_init(&usbtv->v4l2_lock);
	mutex_init(&usbtv->vb2q_lock);
	INIT_LIST_HEAD(&usbtv->bufs);

	/* videobuf2 structure */
	usbtv->vb2q.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	usbtv->vb2q.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
	usbtv->vb2q.drv_priv = usbtv;
	usbtv->vb2q.buf_struct_size = sizeof(struct usbtv_buf);
	usbtv->vb2q.ops = &usbtv_vb2_ops;
	usbtv->vb2q.mem_ops = &vb2_vmalloc_memops;
	ret = vb2_queue_init(&usbtv->vb2q);
	if (ret < 0) {
		dev_warn(dev, "Could not initialize videobuf2 queue\n");
		goto usbtv_fail;
	}

	/* v4l2 structure */
	usbtv->v4l2_dev.release = usbtv_release;
	ret = v4l2_device_register(dev, &usbtv->v4l2_dev);
	if (ret < 0) {
		dev_warn(dev, "Could not register v4l2 device\n");
		goto v4l2_fail;
	}

	usb_set_intfdata(intf, usbtv);

	/* Video structure */
	strlcpy(usbtv->vdev.name, "usbtv", sizeof(usbtv->vdev.name));
	usbtv->vdev.v4l2_dev = &usbtv->v4l2_dev;
	usbtv->vdev.release = video_device_release_empty;
	usbtv->vdev.fops = &usbtv_fops;
	usbtv->vdev.ioctl_ops = &usbtv_ioctl_ops;
	usbtv->vdev.tvnorms = USBTV_TV_STD;
	usbtv->vdev.lock = &usbtv->v4l2_lock;
	set_bit(V4L2_FL_USE_FH_PRIO, &usbtv->vdev.flags);
	video_set_drvdata(&usbtv->vdev, usbtv);
	ret = video_register_device(&usbtv->vdev, VFL_TYPE_GRABBER, -1);
	if (ret < 0) {
		dev_warn(dev, "Could not register video device\n");
		goto vdev_fail;
	}

	dev_info(dev, "Fushicai USBTV007 Video Grabber\n");
	return 0;

vdev_fail:
	v4l2_device_unregister(&usbtv->v4l2_dev);
v4l2_fail:
	vb2_queue_release(&usbtv->vb2q);
usbtv_fail:
	kfree(usbtv);

	return ret;
}

static void usbtv_disconnect(struct usb_interface *intf)
{
	struct usbtv *usbtv = usb_get_intfdata(intf);

	mutex_lock(&usbtv->vb2q_lock);
	mutex_lock(&usbtv->v4l2_lock);

	usbtv_stop(usbtv);
	usb_set_intfdata(intf, NULL);
	video_unregister_device(&usbtv->vdev);
	v4l2_device_disconnect(&usbtv->v4l2_dev);
	usb_put_dev(usbtv->udev);
	usbtv->udev = NULL;

	mutex_unlock(&usbtv->v4l2_lock);
	mutex_unlock(&usbtv->vb2q_lock);

	v4l2_device_put(&usbtv->v4l2_dev);
}

struct usb_driver usbtv_usb_driver = {
	.name = "usbtv",
	.id_table = usbtv_id_table,
	.probe = usbtv_probe,
	.disconnect = usbtv_disconnect,
};

static int __init usbtv_init(void)
{
	int retval;
	retval = usb_register(&usbtv_usb_driver);
	if (retval)
		goto out;

	printk(KERN_INFO KBUILD_MODNAME ": Loaded\n");

out:
	return retval;
}

static void __exit usbtv_exit(void)
{
	usb_deregister(&usbtv_usb_driver);
}

module_init(usbtv_init);
module_exit(usbtv_exit);

MODULE_AUTHOR("Lubomir Rintel");
MODULE_DESCRIPTION("Fushicai USBTV007 Video Grabber Driver");
MODULE_LICENSE("Dual BSD/GPL");