/*
 *
 *  $Id$
 *
 *  Copyright (C) 2005 Mike Isely <isely@pobox.com>
 *  Copyright (C) 2004 Aurelien Alleaume <slts@free.fr>
 *
 *  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
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/kernel.h>
#include "pvrusb2-context.h"
#include "pvrusb2-hdw.h"
#include "pvrusb2.h"
#include "pvrusb2-debug.h"
#include "pvrusb2-v4l2.h"
#include "pvrusb2-ioread.h"
#include <linux/videodev2.h>
#include <media/v4l2-common.h>

struct pvr2_v4l2_dev;
struct pvr2_v4l2_fh;
struct pvr2_v4l2;

/* V4L no longer provide the ability to set / get a private context pointer
   (i.e. video_get_drvdata / video_set_drvdata), which means we have to
   concoct our own context locating mechanism.  Supposedly this is intended
   to simplify driver implementation.  It's not clear to me how that can
   possibly be true.  Our solution here is to maintain a lookup table of
   our context instances, indexed by the minor device number of the V4L
   device.  See pvr2_v4l2_open() for some implications of this approach. */
static struct pvr2_v4l2_dev *devices[256];
static DEFINE_MUTEX(device_lock);

struct pvr2_v4l2_dev {
	struct pvr2_v4l2 *v4lp;
	struct video_device *vdev;
	struct pvr2_context_stream *stream;
	int ctxt_idx;
	enum pvr2_config config;
};

struct pvr2_v4l2_fh {
	struct pvr2_channel channel;
	struct pvr2_v4l2_dev *dev_info;
	enum v4l2_priority prio;
	struct pvr2_ioread *rhp;
	struct file *file;
	struct pvr2_v4l2 *vhead;
	struct pvr2_v4l2_fh *vnext;
	struct pvr2_v4l2_fh *vprev;
	wait_queue_head_t wait_data;
	int fw_mode_flag;
};

struct pvr2_v4l2 {
	struct pvr2_channel channel;
	struct pvr2_v4l2_fh *vfirst;
	struct pvr2_v4l2_fh *vlast;

	struct v4l2_prio_state prio;

	/* streams */
	struct pvr2_v4l2_dev video_dev;
};

static int video_nr[PVR_NUM] = {[0 ... PVR_NUM-1] = -1};
module_param_array(video_nr, int, NULL, 0444);
MODULE_PARM_DESC(video_nr, "Offset for device's minor");

struct v4l2_capability pvr_capability ={
	.driver         = "pvrusb2",
	.card           = "Hauppauge WinTV pvr-usb2",
	.bus_info       = "usb",
	.version        = KERNEL_VERSION(0,8,0),
	.capabilities   = (V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VBI_CAPTURE |
			   V4L2_CAP_TUNER | V4L2_CAP_AUDIO |
			   V4L2_CAP_READWRITE),
	.reserved       = {0,0,0,0}
};

static struct v4l2_tuner pvr_v4l2_tuners[]= {
	{
		.index      = 0,
		.name       = "TV Tuner",
		.type           = V4L2_TUNER_ANALOG_TV,
		.capability     = (V4L2_TUNER_CAP_NORM |
				   V4L2_TUNER_CAP_STEREO |
				   V4L2_TUNER_CAP_LANG1 |
				   V4L2_TUNER_CAP_LANG2),
		.rangelow   = 0,
		.rangehigh  = 0,
		.rxsubchans     = V4L2_TUNER_SUB_STEREO,
		.audmode        = V4L2_TUNER_MODE_STEREO,
		.signal         = 0,
		.afc            = 0,
		.reserved       = {0,0,0,0}
	}
};

struct v4l2_fmtdesc pvr_fmtdesc [] = {
	{
		.index          = 0,
		.type           = V4L2_BUF_TYPE_VIDEO_CAPTURE,
		.flags          = V4L2_FMT_FLAG_COMPRESSED,
		.description    = "MPEG1/2",
		// This should really be V4L2_PIX_FMT_MPEG, but xawtv
		// breaks when I do that.
		.pixelformat    = 0, // V4L2_PIX_FMT_MPEG,
		.reserved       = { 0, 0, 0, 0 }
	}
};

#define PVR_FORMAT_PIX  0
#define PVR_FORMAT_VBI  1

struct v4l2_format pvr_format [] = {
	[PVR_FORMAT_PIX] = {
		.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
		.fmt    = {
			.pix        = {
				.width          = 720,
				.height             = 576,
				// This should really be V4L2_PIX_FMT_MPEG,
				// but xawtv breaks when I do that.
				.pixelformat    = 0, // V4L2_PIX_FMT_MPEG,
				.field          = V4L2_FIELD_INTERLACED,
				.bytesperline   = 0,  // doesn't make sense
						      // here
				//FIXME : Don't know what to put here...
				.sizeimage          = (32*1024),
				.colorspace     = 0, // doesn't make sense here
				.priv           = 0
			}
		}
	},
	[PVR_FORMAT_VBI] = {
		.type   = V4L2_BUF_TYPE_VBI_CAPTURE,
		.fmt    = {
			.vbi        = {
				.sampling_rate = 27000000,
				.offset = 248,
				.samples_per_line = 1443,
				.sample_format = V4L2_PIX_FMT_GREY,
				.start = { 0, 0 },
				.count = { 0, 0 },
				.flags = 0,
				.reserved = { 0, 0 }
			}
		}
	}
};

/*
 * pvr_ioctl()
 *
 * This is part of Video 4 Linux API. The procedure handles ioctl() calls.
 *
 */
static int pvr2_v4l2_do_ioctl(struct inode *inode, struct file *file,
			      unsigned int cmd, void *arg)
{
	struct pvr2_v4l2_fh *fh = file->private_data;
	struct pvr2_v4l2 *vp = fh->vhead;
	struct pvr2_v4l2_dev *dev_info = fh->dev_info;
	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
	int ret = -EINVAL;

	if (pvrusb2_debug & PVR2_TRACE_V4LIOCTL) {
		v4l_print_ioctl(pvr2_hdw_get_driver_name(hdw),cmd);
	}

	if (!pvr2_hdw_dev_ok(hdw)) {
		pvr2_trace(PVR2_TRACE_ERROR_LEGS,
			   "ioctl failed - bad or no context");
		return -EFAULT;
	}

	/* check priority */
	switch (cmd) {
	case VIDIOC_S_CTRL:
	case VIDIOC_S_STD:
	case VIDIOC_S_INPUT:
	case VIDIOC_S_TUNER:
	case VIDIOC_S_FREQUENCY:
		ret = v4l2_prio_check(&vp->prio, &fh->prio);
		if (ret)
			return ret;
	}

	switch (cmd) {
	case VIDIOC_QUERYCAP:
	{
		struct v4l2_capability *cap = arg;

		memcpy(cap, &pvr_capability, sizeof(struct v4l2_capability));

		ret = 0;
		break;
	}

	case VIDIOC_G_PRIORITY:
	{
		enum v4l2_priority *p = arg;

		*p = v4l2_prio_max(&vp->prio);
		ret = 0;
		break;
	}

	case VIDIOC_S_PRIORITY:
	{
		enum v4l2_priority *prio = arg;

		ret = v4l2_prio_change(&vp->prio, &fh->prio, *prio);
		break;
	}

	case VIDIOC_ENUMSTD:
	{
		struct v4l2_standard *vs = (struct v4l2_standard *)arg;
		int idx = vs->index;
		ret = pvr2_hdw_get_stdenum_value(hdw,vs,idx+1);
		break;
	}

	case VIDIOC_G_STD:
	{
		int val = 0;
		ret = pvr2_ctrl_get_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_STDCUR),&val);
		*(v4l2_std_id *)arg = val;
		break;
	}

	case VIDIOC_S_STD:
	{
		ret = pvr2_ctrl_set_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_STDCUR),
			*(v4l2_std_id *)arg);
		break;
	}

	case VIDIOC_ENUMINPUT:
	{
		struct pvr2_ctrl *cptr;
		struct v4l2_input *vi = (struct v4l2_input *)arg;
		struct v4l2_input tmp;
		unsigned int cnt;

		cptr = pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_INPUT);

		memset(&tmp,0,sizeof(tmp));
		tmp.index = vi->index;
		ret = 0;
		switch (vi->index) {
		case PVR2_CVAL_INPUT_TV:
		case PVR2_CVAL_INPUT_RADIO:
			tmp.type = V4L2_INPUT_TYPE_TUNER;
			break;
		case PVR2_CVAL_INPUT_SVIDEO:
		case PVR2_CVAL_INPUT_COMPOSITE:
			tmp.type = V4L2_INPUT_TYPE_CAMERA;
			break;
		default:
			ret = -EINVAL;
			break;
		}
		if (ret < 0) break;

		cnt = 0;
		pvr2_ctrl_get_valname(cptr,vi->index,
				      tmp.name,sizeof(tmp.name)-1,&cnt);
		tmp.name[cnt] = 0;

		/* Don't bother with audioset, since this driver currently
		   always switches the audio whenever the video is
		   switched. */

		/* Handling std is a tougher problem.  It doesn't make
		   sense in cases where a device might be multi-standard.
		   We could just copy out the current value for the
		   standard, but it can change over time.  For now just
		   leave it zero. */

		memcpy(vi, &tmp, sizeof(tmp));

		ret = 0;
		break;
	}

	case VIDIOC_G_INPUT:
	{
		struct pvr2_ctrl *cptr;
		struct v4l2_input *vi = (struct v4l2_input *)arg;
		int val;
		cptr = pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_INPUT);
		val = 0;
		ret = pvr2_ctrl_get_value(cptr,&val);
		vi->index = val;
		break;
	}

	case VIDIOC_S_INPUT:
	{
		struct v4l2_input *vi = (struct v4l2_input *)arg;
		ret = pvr2_ctrl_set_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_INPUT),
			vi->index);
		break;
	}

	case VIDIOC_ENUMAUDIO:
	{
		ret = -EINVAL;
		break;
	}

	case VIDIOC_G_AUDIO:
	{
		ret = -EINVAL;
		break;
	}

	case VIDIOC_S_AUDIO:
	{
		ret = -EINVAL;
		break;
	}
	case VIDIOC_G_TUNER:
	{
		struct v4l2_tuner *vt = (struct v4l2_tuner *)arg;
		unsigned int status_mask;
		int val;
		if (vt->index !=0) break;

		status_mask = pvr2_hdw_get_signal_status(hdw);

		memcpy(vt, &pvr_v4l2_tuners[vt->index],
		       sizeof(struct v4l2_tuner));

		vt->signal = 0;
		if (status_mask & PVR2_SIGNAL_OK) {
			if (status_mask & PVR2_SIGNAL_STEREO) {
				vt->rxsubchans = V4L2_TUNER_SUB_STEREO;
			} else {
				vt->rxsubchans = V4L2_TUNER_SUB_MONO;
			}
			if (status_mask & PVR2_SIGNAL_SAP) {
				vt->rxsubchans |= (V4L2_TUNER_SUB_LANG1 |
						   V4L2_TUNER_SUB_LANG2);
			}
			vt->signal = 65535;
		}

		val = 0;
		ret = pvr2_ctrl_get_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_AUDIOMODE),
			&val);
		vt->audmode = val;
		break;
	}

	case VIDIOC_S_TUNER:
	{
		struct v4l2_tuner *vt=(struct v4l2_tuner *)arg;

		if (vt->index != 0)
			break;

		ret = pvr2_ctrl_set_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_AUDIOMODE),
			vt->audmode);
	}

	case VIDIOC_S_FREQUENCY:
	{
		const struct v4l2_frequency *vf = (struct v4l2_frequency *)arg;
		ret = pvr2_ctrl_set_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_FREQUENCY),
			vf->frequency * 62500);
		break;
	}

	case VIDIOC_G_FREQUENCY:
	{
		struct v4l2_frequency *vf = (struct v4l2_frequency *)arg;
		int val = 0;
		ret = pvr2_ctrl_get_value(
			pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_FREQUENCY),
			&val);
		val /= 62500;
		vf->frequency = val;
		break;
	}

	case VIDIOC_ENUM_FMT:
	{
		struct v4l2_fmtdesc *fd = (struct v4l2_fmtdesc *)arg;

		/* Only one format is supported : mpeg.*/
		if (fd->index != 0)
			break;

		memcpy(fd, pvr_fmtdesc, sizeof(struct v4l2_fmtdesc));
		ret = 0;
		break;
	}

	case VIDIOC_G_FMT:
	{
		struct v4l2_format *vf = (struct v4l2_format *)arg;
		int val;
		switch(vf->type) {
		case V4L2_BUF_TYPE_VIDEO_CAPTURE:
			memcpy(vf, &pvr_format[PVR_FORMAT_PIX],
			       sizeof(struct v4l2_format));
			val = 0;
			pvr2_ctrl_get_value(
				pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_HRES),
				&val);
			vf->fmt.pix.width = val;
			val = 0;
			pvr2_ctrl_get_value(
				pvr2_hdw_get_ctrl_by_id(hdw,
							PVR2_CID_INTERLACE),
				&val);
			if (val) vf->fmt.pix.width /= 2;
			val = 0;
			pvr2_ctrl_get_value(
				pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_VRES),
				&val);
			vf->fmt.pix.height = val;
			ret = 0;
			break;
		case V4L2_BUF_TYPE_VBI_CAPTURE:
			// ????? Still need to figure out to do VBI correctly
			ret = -EINVAL;
			break;
		default:
			ret = -EINVAL;
			break;
		}
		break;
	}

	case VIDIOC_TRY_FMT:
	case VIDIOC_S_FMT:
	{
		struct v4l2_format *vf = (struct v4l2_format *)arg;

		ret = 0;
		switch(vf->type) {
		case V4L2_BUF_TYPE_VIDEO_CAPTURE: {
			int h = vf->fmt.pix.height;
			int w = vf->fmt.pix.width;
			int vd_std, hf, hh;

			vd_std = 0;
			pvr2_ctrl_get_value(
				pvr2_hdw_get_ctrl_by_id(hdw,PVR2_CID_STDCUR),
				&vd_std);
			if (vd_std & V4L2_STD_525_60) {
				hf=480;
			} else {
				hf=576;
			}
			hh = (int) (hf / 2);

			memcpy(vf, &pvr_format[PVR_FORMAT_PIX],
			       sizeof(struct v4l2_format));
			if (w > 720)
				vf->fmt.pix.width = 720;
			vf->fmt.pix.width &= 0xff0;
			vf->fmt.pix.height = (h > hh) ? hf : hh;

			if (cmd == VIDIOC_S_FMT) {
				pvr2_ctrl_set_value(
					pvr2_hdw_get_ctrl_by_id(hdw,
								PVR2_CID_HRES),
					vf->fmt.pix.width);
				pvr2_ctrl_set_value(
					pvr2_hdw_get_ctrl_by_id(hdw,
								PVR2_CID_VRES),
					vf->fmt.pix.height);
				pvr2_ctrl_set_value(
					pvr2_hdw_get_ctrl_by_id(
						hdw,PVR2_CID_INTERLACE),
					vf->fmt.pix.height != hf);
			}
		} break;
		case V4L2_BUF_TYPE_VBI_CAPTURE:
			// ????? Still need to figure out to do VBI correctly
			ret = -EINVAL;
			break;
		default:
			ret = -EINVAL;
			break;
		}
		break;
	}

	case VIDIOC_STREAMON:
	{
		ret = pvr2_hdw_set_stream_type(hdw,dev_info->config);
		if (ret < 0) return ret;
		ret = pvr2_hdw_set_streaming(hdw,!0);
		break;
	}

	case VIDIOC_STREAMOFF:
	{
		ret = pvr2_hdw_set_streaming(hdw,0);
		break;
	}

	case VIDIOC_QUERYCTRL:
	{
		struct pvr2_ctrl *cptr;
		struct v4l2_queryctrl *vc = (struct v4l2_queryctrl *)arg;
		ret = 0;
		cptr = pvr2_hdw_get_ctrl_v4l(hdw,vc->id);
		if (!cptr) {
			ret = -EINVAL;
			break;
		}

		strlcpy(vc->name,pvr2_ctrl_get_name(cptr),sizeof(vc->name));
		vc->default_value = pvr2_ctrl_get_def(cptr);
		switch (pvr2_ctrl_get_type(cptr)) {
		case pvr2_ctl_enum:
			vc->type = V4L2_CTRL_TYPE_MENU;
			vc->minimum = 0;
			vc->maximum = pvr2_ctrl_get_cnt(cptr) - 1;
			vc->step = 1;
			break;
		case pvr2_ctl_int:
			vc->type = V4L2_CTRL_TYPE_INTEGER;
			vc->minimum = pvr2_ctrl_get_min(cptr);
			vc->maximum = pvr2_ctrl_get_max(cptr);
			vc->step = 1;
			break;
		default:
			ret = -EINVAL;
			break;
		}
		break;
	}

	case VIDIOC_QUERYMENU:
	{
		struct v4l2_querymenu *vm = (struct v4l2_querymenu *)arg;
		unsigned int cnt = 0;
		ret = pvr2_ctrl_get_valname(pvr2_hdw_get_ctrl_v4l(hdw,vm->id),
					    vm->index,
					    vm->name,sizeof(vm->name)-1,
					    &cnt);
		vm->name[cnt] = 0;
		break;
	}

	case VIDIOC_G_CTRL:
	{
		struct v4l2_control *vc = (struct v4l2_control *)arg;
		int val = 0;
		ret = pvr2_ctrl_get_value(pvr2_hdw_get_ctrl_v4l(hdw,vc->id),
					  &val);
		vc->value = val;
		break;
	}

	case VIDIOC_S_CTRL:
	{
		struct v4l2_control *vc = (struct v4l2_control *)arg;
		ret = pvr2_ctrl_set_value(pvr2_hdw_get_ctrl_v4l(hdw,vc->id),
					  vc->value);
		break;
	}

	case VIDIOC_LOG_STATUS:
	{
		int nr = pvr2_hdw_get_unit_number(hdw);

		printk(KERN_INFO "pvrusb2: =================  START STATUS CARD #%d  =================\n", nr);
		pvr2_hdw_trigger_module_log(hdw);
		printk(KERN_INFO "pvrusb2: ==================  END STATUS CARD #%d  ==================\n", nr);
		ret = 0;
		break;
	}

	default :
		ret = v4l_compat_translate_ioctl(inode,file,cmd,
						 arg,pvr2_v4l2_do_ioctl);
	}

	pvr2_hdw_commit_ctl(hdw);

	if (ret < 0) {
		if (pvrusb2_debug & PVR2_TRACE_V4LIOCTL) {
			pvr2_trace(PVR2_TRACE_ERROR_LEGS,
				   "pvr2_v4l2_do_ioctl failure, ret=%d",ret);
		} else {
			if (pvrusb2_debug & PVR2_TRACE_ERROR_LEGS) {
				pvr2_trace(PVR2_TRACE_ERROR_LEGS,
					   "pvr2_v4l2_do_ioctl failure, ret=%d"
					   " command was:",ret);
				v4l_print_ioctl(pvr2_hdw_get_driver_name(hdw),
						cmd);
			}
		}
	} else {
		pvr2_trace(PVR2_TRACE_V4LIOCTL,
			   "pvr2_v4l2_do_ioctl complete, ret=%d (0x%x)",
			   ret,ret);
	}
	return ret;
}


static void pvr2_v4l2_dev_destroy(struct pvr2_v4l2_dev *dip)
{
	pvr2_trace(PVR2_TRACE_INIT,
		   "unregistering device video%d [%s]",
		   dip->vdev->minor,pvr2_config_get_name(dip->config));
	if (dip->ctxt_idx >= 0) {
		mutex_lock(&device_lock);
		devices[dip->ctxt_idx] = NULL;
		dip->ctxt_idx = -1;
		mutex_unlock(&device_lock);
	}
	video_unregister_device(dip->vdev);
}


static void pvr2_v4l2_destroy_no_lock(struct pvr2_v4l2 *vp)
{
	pvr2_hdw_v4l_store_minor_number(vp->channel.mc_head->hdw,-1);
	pvr2_v4l2_dev_destroy(&vp->video_dev);

	pvr2_trace(PVR2_TRACE_STRUCT,"Destroying pvr2_v4l2 id=%p",vp);
	pvr2_channel_done(&vp->channel);
	kfree(vp);
}


void pvr2_v4l2_internal_check(struct pvr2_channel *chp)
{
	struct pvr2_v4l2 *vp;
	vp = container_of(chp,struct pvr2_v4l2,channel);
	if (!vp->channel.mc_head->disconnect_flag) return;
	if (vp->vfirst) return;
	pvr2_v4l2_destroy_no_lock(vp);
}


int pvr2_v4l2_ioctl(struct inode *inode, struct file *file,
		    unsigned int cmd, unsigned long arg)
{

/* Temporary hack : use ivtv api until a v4l2 one is available. */
#define IVTV_IOC_G_CODEC        0xFFEE7703
#define IVTV_IOC_S_CODEC        0xFFEE7704
	if (cmd == IVTV_IOC_G_CODEC || cmd == IVTV_IOC_S_CODEC) return 0;
	return video_usercopy(inode, file, cmd, arg, pvr2_v4l2_do_ioctl);
}


int pvr2_v4l2_release(struct inode *inode, struct file *file)
{
	struct pvr2_v4l2_fh *fhp = file->private_data;
	struct pvr2_v4l2 *vp = fhp->vhead;
	struct pvr2_context *mp = fhp->vhead->channel.mc_head;

	pvr2_trace(PVR2_TRACE_OPEN_CLOSE,"pvr2_v4l2_release");

	if (fhp->rhp) {
		struct pvr2_stream *sp;
		struct pvr2_hdw *hdw;
		hdw = fhp->channel.mc_head->hdw;
		pvr2_hdw_set_streaming(hdw,0);
		sp = pvr2_ioread_get_stream(fhp->rhp);
		if (sp) pvr2_stream_set_callback(sp,0,0);
		pvr2_ioread_destroy(fhp->rhp);
		fhp->rhp = 0;
	}
	v4l2_prio_close(&vp->prio, &fhp->prio);
	file->private_data = NULL;

	pvr2_context_enter(mp); do {
		if (fhp->vnext) {
			fhp->vnext->vprev = fhp->vprev;
		} else {
			vp->vlast = fhp->vprev;
		}
		if (fhp->vprev) {
			fhp->vprev->vnext = fhp->vnext;
		} else {
			vp->vfirst = fhp->vnext;
		}
		fhp->vnext = 0;
		fhp->vprev = 0;
		fhp->vhead = 0;
		pvr2_channel_done(&fhp->channel);
		pvr2_trace(PVR2_TRACE_STRUCT,
			   "Destroying pvr_v4l2_fh id=%p",fhp);
		kfree(fhp);
		if (vp->channel.mc_head->disconnect_flag && !vp->vfirst) {
			pvr2_v4l2_destroy_no_lock(vp);
		}
	} while (0); pvr2_context_exit(mp);
	return 0;
}


int pvr2_v4l2_open(struct inode *inode, struct file *file)
{
	struct pvr2_v4l2_dev *dip = 0; /* Our own context pointer */
	struct pvr2_v4l2_fh *fhp;
	struct pvr2_v4l2 *vp;
	struct pvr2_hdw *hdw;

	mutex_lock(&device_lock);
	/* MCI 7-Jun-2006 Even though we're just doing what amounts to an
	   atomic read of the device mapping array here, we still need the
	   mutex.  The problem is that there is a tiny race possible when
	   we register the device.  We can't update the device mapping
	   array until after the device has been registered, owing to the
	   fact that we can't know the minor device number until after the
	   registration succeeds.  And if another thread tries to open the
	   device in the window of time after registration but before the
	   map is updated, then it will get back an erroneous null pointer
	   and the open will result in a spurious failure.  The only way to
	   prevent that is to (a) be inside the mutex here before we access
	   the array, and (b) cover the entire registration process later
	   on with this same mutex.  Thus if we get inside the mutex here,
	   then we can be assured that the registration process actually
	   completed correctly.  This is an unhappy complication from the
	   use of global data in a driver that lives in a preemptible
	   environment.  It sure would be nice if the video device itself
	   had a means for storing and retrieving a local context pointer.
	   Oh wait.  It did.  But now it's gone.  Silly me. */
	{
		unsigned int midx = iminor(file->f_dentry->d_inode);
		if (midx < sizeof(devices)/sizeof(devices[0])) {
			dip = devices[midx];
		}
	}
	mutex_unlock(&device_lock);

	if (!dip) return -ENODEV; /* Should be impossible but I'm paranoid */

	vp = dip->v4lp;
	hdw = vp->channel.hdw;

	pvr2_trace(PVR2_TRACE_OPEN_CLOSE,"pvr2_v4l2_open");

	if (!pvr2_hdw_dev_ok(hdw)) {
		pvr2_trace(PVR2_TRACE_OPEN_CLOSE,
			   "pvr2_v4l2_open: hardware not ready");
		return -EIO;
	}

	fhp = kmalloc(sizeof(*fhp),GFP_KERNEL);
	if (!fhp) {
		return -ENOMEM;
	}
	memset(fhp,0,sizeof(*fhp));

	init_waitqueue_head(&fhp->wait_data);
	fhp->dev_info = dip;

	pvr2_context_enter(vp->channel.mc_head); do {
		pvr2_trace(PVR2_TRACE_STRUCT,"Creating pvr_v4l2_fh id=%p",fhp);
		pvr2_channel_init(&fhp->channel,vp->channel.mc_head);
		fhp->vnext = 0;
		fhp->vprev = vp->vlast;
		if (vp->vlast) {
			vp->vlast->vnext = fhp;
		} else {
			vp->vfirst = fhp;
		}
		vp->vlast = fhp;
		fhp->vhead = vp;
	} while (0); pvr2_context_exit(vp->channel.mc_head);

	fhp->file = file;
	file->private_data = fhp;
	v4l2_prio_open(&vp->prio,&fhp->prio);

	fhp->fw_mode_flag = pvr2_hdw_cpufw_get_enabled(hdw);

	return 0;
}


static void pvr2_v4l2_notify(struct pvr2_v4l2_fh *fhp)
{
	wake_up(&fhp->wait_data);
}

static int pvr2_v4l2_iosetup(struct pvr2_v4l2_fh *fh)
{
	int ret;
	struct pvr2_stream *sp;
	struct pvr2_hdw *hdw;
	if (fh->rhp) return 0;

	/* First read() attempt.  Try to claim the stream and start
	   it... */
	if ((ret = pvr2_channel_claim_stream(&fh->channel,
					     fh->dev_info->stream)) != 0) {
		/* Someone else must already have it */
		return ret;
	}

	fh->rhp = pvr2_channel_create_mpeg_stream(fh->dev_info->stream);
	if (!fh->rhp) {
		pvr2_channel_claim_stream(&fh->channel,0);
		return -ENOMEM;
	}

	hdw = fh->channel.mc_head->hdw;
	sp = fh->dev_info->stream->stream;
	pvr2_stream_set_callback(sp,(pvr2_stream_callback)pvr2_v4l2_notify,fh);
	pvr2_hdw_set_stream_type(hdw,fh->dev_info->config);
	pvr2_hdw_set_streaming(hdw,!0);
	ret = pvr2_ioread_set_enabled(fh->rhp,!0);

	return ret;
}


static ssize_t pvr2_v4l2_read(struct file *file,
			      char __user *buff, size_t count, loff_t *ppos)
{
	struct pvr2_v4l2_fh *fh = file->private_data;
	int ret;

	if (fh->fw_mode_flag) {
		struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
		char *tbuf;
		int c1,c2;
		int tcnt = 0;
		unsigned int offs = *ppos;

		tbuf = kmalloc(PAGE_SIZE,GFP_KERNEL);
		if (!tbuf) return -ENOMEM;

		while (count) {
			c1 = count;
			if (c1 > PAGE_SIZE) c1 = PAGE_SIZE;
			c2 = pvr2_hdw_cpufw_get(hdw,offs,tbuf,c1);
			if (c2 < 0) {
				tcnt = c2;
				break;
			}
			if (!c2) break;
			if (copy_to_user(buff,tbuf,c2)) {
				tcnt = -EFAULT;
				break;
			}
			offs += c2;
			tcnt += c2;
			buff += c2;
			count -= c2;
			*ppos += c2;
		}
		kfree(tbuf);
		return tcnt;
	}

	if (!fh->rhp) {
		ret = pvr2_v4l2_iosetup(fh);
		if (ret) {
			return ret;
		}
	}

	for (;;) {
		ret = pvr2_ioread_read(fh->rhp,buff,count);
		if (ret >= 0) break;
		if (ret != -EAGAIN) break;
		if (file->f_flags & O_NONBLOCK) break;
		/* Doing blocking I/O.  Wait here. */
		ret = wait_event_interruptible(
			fh->wait_data,
			pvr2_ioread_avail(fh->rhp) >= 0);
		if (ret < 0) break;
	}

	return ret;
}


static unsigned int pvr2_v4l2_poll(struct file *file, poll_table *wait)
{
	unsigned int mask = 0;
	struct pvr2_v4l2_fh *fh = file->private_data;
	int ret;

	if (fh->fw_mode_flag) {
		mask |= POLLIN | POLLRDNORM;
		return mask;
	}

	if (!fh->rhp) {
		ret = pvr2_v4l2_iosetup(fh);
		if (ret) return POLLERR;
	}

	poll_wait(file,&fh->wait_data,wait);

	if (pvr2_ioread_avail(fh->rhp) >= 0) {
		mask |= POLLIN | POLLRDNORM;
	}

	return mask;
}


static struct file_operations vdev_fops = {
	.owner      = THIS_MODULE,
	.open       = pvr2_v4l2_open,
	.release    = pvr2_v4l2_release,
	.read       = pvr2_v4l2_read,
	.ioctl      = pvr2_v4l2_ioctl,
	.llseek     = no_llseek,
	.poll       = pvr2_v4l2_poll,
};


#define VID_HARDWARE_PVRUSB2    38  /* FIXME : need a good value */

static struct video_device vdev_template = {
	.owner      = THIS_MODULE,
	.type       = VID_TYPE_CAPTURE | VID_TYPE_TUNER,
	.type2      = (V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VBI_CAPTURE
		       | V4L2_CAP_TUNER | V4L2_CAP_AUDIO
		       | V4L2_CAP_READWRITE),
	.hardware   = VID_HARDWARE_PVRUSB2,
	.fops       = &vdev_fops,
};


static void pvr2_v4l2_dev_init(struct pvr2_v4l2_dev *dip,
			       struct pvr2_v4l2 *vp,
			       enum pvr2_config cfg)
{
	int mindevnum;
	int unit_number;
	int v4l_type;
	dip->v4lp = vp;
	dip->config = cfg;


	switch (cfg) {
	case pvr2_config_mpeg:
		v4l_type = VFL_TYPE_GRABBER;
		dip->stream = &vp->channel.mc_head->video_stream;
		break;
	case pvr2_config_vbi:
		v4l_type = VFL_TYPE_VBI;
		break;
	case pvr2_config_radio:
		v4l_type = VFL_TYPE_RADIO;
		break;
	default:
		/* Bail out (this should be impossible) */
		err("Failed to set up pvrusb2 v4l dev"
		    " due to unrecognized config");
		return;
	}

	if (!dip->stream) {
		err("Failed to set up pvrusb2 v4l dev"
		    " due to missing stream instance");
		return;
	}

	dip->vdev = video_device_alloc();
	if (!dip->vdev) {
		err("Alloc of pvrusb2 v4l video device failed");
		return;
	}

	memcpy(dip->vdev,&vdev_template,sizeof(vdev_template));
	dip->vdev->release = video_device_release;
	mutex_lock(&device_lock);

	mindevnum = -1;
	unit_number = pvr2_hdw_get_unit_number(vp->channel.mc_head->hdw);
	if ((unit_number >= 0) && (unit_number < PVR_NUM)) {
		mindevnum = video_nr[unit_number];
	}
	if ((video_register_device(dip->vdev, v4l_type, mindevnum) < 0) &&
	    (video_register_device(dip->vdev, v4l_type, -1) < 0)) {
		err("Failed to register pvrusb2 v4l video device");
	} else {
		pvr2_trace(PVR2_TRACE_INIT,
			   "registered device video%d [%s]",
			   dip->vdev->minor,pvr2_config_get_name(dip->config));
	}

	if ((dip->vdev->minor < sizeof(devices)/sizeof(devices[0])) &&
	    (devices[dip->vdev->minor] == NULL)) {
		dip->ctxt_idx = dip->vdev->minor;
		devices[dip->ctxt_idx] = dip;
	}
	mutex_unlock(&device_lock);

	pvr2_hdw_v4l_store_minor_number(vp->channel.mc_head->hdw,
					dip->vdev->minor);
}


struct pvr2_v4l2 *pvr2_v4l2_create(struct pvr2_context *mnp)
{
	struct pvr2_v4l2 *vp;

	vp = kmalloc(sizeof(*vp),GFP_KERNEL);
	if (!vp) return vp;
	memset(vp,0,sizeof(*vp));
	vp->video_dev.ctxt_idx = -1;
	pvr2_channel_init(&vp->channel,mnp);
	pvr2_trace(PVR2_TRACE_STRUCT,"Creating pvr2_v4l2 id=%p",vp);

	vp->channel.check_func = pvr2_v4l2_internal_check;

	/* register streams */
	pvr2_v4l2_dev_init(&vp->video_dev,vp,pvr2_config_mpeg);


	return vp;
}

/*
  Stuff for Emacs to see, in order to encourage consistent editing style:
  *** Local Variables: ***
  *** mode: c ***
  *** fill-column: 75 ***
  *** tab-width: 8 ***
  *** c-basic-offset: 8 ***
  *** End: ***
  */