/*
 * dvbdev.c
 *
 * Copyright (C) 2000 Ralph  Metzler <ralph@convergence.de>
 *                  & Marcus Metzler <marcus@convergence.de>
 *                    for convergence integrated media GmbH
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * 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 Lesser 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/types.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include "dvbdev.h"

static DEFINE_MUTEX(dvbdev_mutex);
static int dvbdev_debug;

module_param(dvbdev_debug, int, 0644);
MODULE_PARM_DESC(dvbdev_debug, "Turn on/off device debugging (default:off).");

#define dprintk if (dvbdev_debug) printk

static LIST_HEAD(dvb_adapter_list);
static DEFINE_MUTEX(dvbdev_register_lock);

static const char * const dnames[] = {
	"video", "audio", "sec", "frontend", "demux", "dvr", "ca",
	"net", "osd"
};

#ifdef CONFIG_DVB_DYNAMIC_MINORS
#define MAX_DVB_MINORS		256
#define DVB_MAX_IDS		MAX_DVB_MINORS
#else
#define DVB_MAX_IDS		4
#define nums2minor(num,type,id)	((num << 6) | (id << 4) | type)
#define MAX_DVB_MINORS		(DVB_MAX_ADAPTERS*64)
#endif

static struct class *dvb_class;

static struct dvb_device *dvb_minors[MAX_DVB_MINORS];
static DECLARE_RWSEM(minor_rwsem);

static int dvb_device_open(struct inode *inode, struct file *file)
{
	struct dvb_device *dvbdev;

	mutex_lock(&dvbdev_mutex);
	down_read(&minor_rwsem);
	dvbdev = dvb_minors[iminor(inode)];

	if (dvbdev && dvbdev->fops) {
		int err = 0;
		const struct file_operations *old_fops;

		file->private_data = dvbdev;
		old_fops = file->f_op;
		file->f_op = fops_get(dvbdev->fops);
		if (file->f_op == NULL) {
			file->f_op = old_fops;
			goto fail;
		}
		if(file->f_op->open)
			err = file->f_op->open(inode,file);
		if (err) {
			fops_put(file->f_op);
			file->f_op = fops_get(old_fops);
		}
		fops_put(old_fops);
		up_read(&minor_rwsem);
		mutex_unlock(&dvbdev_mutex);
		return err;
	}
fail:
	up_read(&minor_rwsem);
	mutex_unlock(&dvbdev_mutex);
	return -ENODEV;
}


static const struct file_operations dvb_device_fops =
{
	.owner =	THIS_MODULE,
	.open =		dvb_device_open,
	.llseek =	noop_llseek,
};

static struct cdev dvb_device_cdev;

int dvb_generic_open(struct inode *inode, struct file *file)
{
	struct dvb_device *dvbdev = file->private_data;

	if (!dvbdev)
		return -ENODEV;

	if (!dvbdev->users)
		return -EBUSY;

	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
		if (!dvbdev->readers)
			return -EBUSY;
		dvbdev->readers--;
	} else {
		if (!dvbdev->writers)
			return -EBUSY;
		dvbdev->writers--;
	}

	dvbdev->users--;
	return 0;
}
EXPORT_SYMBOL(dvb_generic_open);


int dvb_generic_release(struct inode *inode, struct file *file)
{
	struct dvb_device *dvbdev = file->private_data;

	if (!dvbdev)
		return -ENODEV;

	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
		dvbdev->readers++;
	} else {
		dvbdev->writers++;
	}

	dvbdev->users++;
	return 0;
}
EXPORT_SYMBOL(dvb_generic_release);


long dvb_generic_ioctl(struct file *file,
		       unsigned int cmd, unsigned long arg)
{
	struct dvb_device *dvbdev = file->private_data;

	if (!dvbdev)
		return -ENODEV;

	if (!dvbdev->kernel_ioctl)
		return -EINVAL;

	return dvb_usercopy(file, cmd, arg, dvbdev->kernel_ioctl);
}
EXPORT_SYMBOL(dvb_generic_ioctl);


static int dvbdev_get_free_id (struct dvb_adapter *adap, int type)
{
	u32 id = 0;

	while (id < DVB_MAX_IDS) {
		struct dvb_device *dev;
		list_for_each_entry(dev, &adap->device_list, list_head)
			if (dev->type == type && dev->id == id)
				goto skip;
		return id;
skip:
		id++;
	}
	return -ENFILE;
}


int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
			const struct dvb_device *template, void *priv, int type)
{
	struct dvb_device *dvbdev;
	struct file_operations *dvbdevfops;
	struct device *clsdev;
	int minor;
	int id;

	mutex_lock(&dvbdev_register_lock);

	if ((id = dvbdev_get_free_id (adap, type)) < 0){
		mutex_unlock(&dvbdev_register_lock);
		*pdvbdev = NULL;
		printk(KERN_ERR "%s: couldn't find free device id\n", __func__);
		return -ENFILE;
	}

	*pdvbdev = dvbdev = kmalloc(sizeof(struct dvb_device), GFP_KERNEL);

	if (!dvbdev){
		mutex_unlock(&dvbdev_register_lock);
		return -ENOMEM;
	}

	dvbdevfops = kzalloc(sizeof(struct file_operations), GFP_KERNEL);

	if (!dvbdevfops){
		kfree (dvbdev);
		mutex_unlock(&dvbdev_register_lock);
		return -ENOMEM;
	}

	memcpy(dvbdev, template, sizeof(struct dvb_device));
	dvbdev->type = type;
	dvbdev->id = id;
	dvbdev->adapter = adap;
	dvbdev->priv = priv;
	dvbdev->fops = dvbdevfops;
	init_waitqueue_head (&dvbdev->wait_queue);

	memcpy(dvbdevfops, template->fops, sizeof(struct file_operations));
	dvbdevfops->owner = adap->module;

	list_add_tail (&dvbdev->list_head, &adap->device_list);

	down_write(&minor_rwsem);
#ifdef CONFIG_DVB_DYNAMIC_MINORS
	for (minor = 0; minor < MAX_DVB_MINORS; minor++)
		if (dvb_minors[minor] == NULL)
			break;

	if (minor == MAX_DVB_MINORS) {
		kfree(dvbdevfops);
		kfree(dvbdev);
		up_write(&minor_rwsem);
		mutex_unlock(&dvbdev_register_lock);
		return -EINVAL;
	}
#else
	minor = nums2minor(adap->num, type, id);
#endif

	dvbdev->minor = minor;
	dvb_minors[minor] = dvbdev;
	up_write(&minor_rwsem);

	mutex_unlock(&dvbdev_register_lock);

	clsdev = device_create(dvb_class, adap->device,
			       MKDEV(DVB_MAJOR, minor),
			       dvbdev, "dvb%d.%s%d", adap->num, dnames[type], id);
	if (IS_ERR(clsdev)) {
		printk(KERN_ERR "%s: failed to create device dvb%d.%s%d (%ld)\n",
		       __func__, adap->num, dnames[type], id, PTR_ERR(clsdev));
		return PTR_ERR(clsdev);
	}

	dprintk(KERN_DEBUG "DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",
		adap->num, dnames[type], id, minor, minor);

	return 0;
}
EXPORT_SYMBOL(dvb_register_device);


void dvb_unregister_device(struct dvb_device *dvbdev)
{
	if (!dvbdev)
		return;

	down_write(&minor_rwsem);
	dvb_minors[dvbdev->minor] = NULL;
	up_write(&minor_rwsem);

	device_destroy(dvb_class, MKDEV(DVB_MAJOR, dvbdev->minor));

	list_del (&dvbdev->list_head);
	kfree (dvbdev->fops);
	kfree (dvbdev);
}
EXPORT_SYMBOL(dvb_unregister_device);

static int dvbdev_check_free_adapter_num(int num)
{
	struct list_head *entry;
	list_for_each(entry, &dvb_adapter_list) {
		struct dvb_adapter *adap;
		adap = list_entry(entry, struct dvb_adapter, list_head);
		if (adap->num == num)
			return 0;
	}
	return 1;
}

static int dvbdev_get_free_adapter_num (void)
{
	int num = 0;

	while (num < DVB_MAX_ADAPTERS) {
		if (dvbdev_check_free_adapter_num(num))
			return num;
		num++;
	}

	return -ENFILE;
}


int dvb_register_adapter(struct dvb_adapter *adap, const char *name,
			 struct module *module, struct device *device,
			 short *adapter_nums)
{
	int i, num;

	mutex_lock(&dvbdev_register_lock);

	for (i = 0; i < DVB_MAX_ADAPTERS; ++i) {
		num = adapter_nums[i];
		if (num >= 0  &&  num < DVB_MAX_ADAPTERS) {
		/* use the one the driver asked for */
			if (dvbdev_check_free_adapter_num(num))
				break;
		} else {
			num = dvbdev_get_free_adapter_num();
			break;
		}
		num = -1;
	}

	if (num < 0) {
		mutex_unlock(&dvbdev_register_lock);
		return -ENFILE;
	}

	memset (adap, 0, sizeof(struct dvb_adapter));
	INIT_LIST_HEAD (&adap->device_list);

	printk(KERN_INFO "DVB: registering new adapter (%s)\n", name);

	adap->num = num;
	adap->name = name;
	adap->module = module;
	adap->device = device;
	adap->mfe_shared = 0;
	adap->mfe_dvbdev = NULL;
	mutex_init (&adap->mfe_lock);

	list_add_tail (&adap->list_head, &dvb_adapter_list);

	mutex_unlock(&dvbdev_register_lock);

	return num;
}
EXPORT_SYMBOL(dvb_register_adapter);


int dvb_unregister_adapter(struct dvb_adapter *adap)
{
	mutex_lock(&dvbdev_register_lock);
	list_del (&adap->list_head);
	mutex_unlock(&dvbdev_register_lock);
	return 0;
}
EXPORT_SYMBOL(dvb_unregister_adapter);

/* if the miracle happens and "generic_usercopy()" is included into
   the kernel, then this can vanish. please don't make the mistake and
   define this as video_usercopy(). this will introduce a dependecy
   to the v4l "videodev.o" module, which is unnecessary for some
   cards (ie. the budget dvb-cards don't need the v4l module...) */
int dvb_usercopy(struct file *file,
		     unsigned int cmd, unsigned long arg,
		     int (*func)(struct file *file,
		     unsigned int cmd, void *arg))
{
	char    sbuf[128];
	void    *mbuf = NULL;
	void    *parg = NULL;
	int     err  = -EINVAL;

	/*  Copy arguments into temp kernel buffer  */
	switch (_IOC_DIR(cmd)) {
	case _IOC_NONE:
		/*
		 * For this command, the pointer is actually an integer
		 * argument.
		 */
		parg = (void *) arg;
		break;
	case _IOC_READ: /* some v4l ioctls are marked wrong ... */
	case _IOC_WRITE:
	case (_IOC_WRITE | _IOC_READ):
		if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
			parg = sbuf;
		} else {
			/* too big to allocate from stack */
			mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
			if (NULL == mbuf)
				return -ENOMEM;
			parg = mbuf;
		}

		err = -EFAULT;
		if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
			goto out;
		break;
	}

	/* call driver */
	if ((err = func(file, cmd, parg)) == -ENOIOCTLCMD)
		err = -ENOTTY;

	if (err < 0)
		goto out;

	/*  Copy results into user buffer  */
	switch (_IOC_DIR(cmd))
	{
	case _IOC_READ:
	case (_IOC_WRITE | _IOC_READ):
		if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
			err = -EFAULT;
		break;
	}

out:
	kfree(mbuf);
	return err;
}

static int dvb_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct dvb_device *dvbdev = dev_get_drvdata(dev);

	add_uevent_var(env, "DVB_ADAPTER_NUM=%d", dvbdev->adapter->num);
	add_uevent_var(env, "DVB_DEVICE_TYPE=%s", dnames[dvbdev->type]);
	add_uevent_var(env, "DVB_DEVICE_NUM=%d", dvbdev->id);
	return 0;
}

static char *dvb_devnode(struct device *dev, umode_t *mode)
{
	struct dvb_device *dvbdev = dev_get_drvdata(dev);

	return kasprintf(GFP_KERNEL, "dvb/adapter%d/%s%d",
		dvbdev->adapter->num, dnames[dvbdev->type], dvbdev->id);
}


static int __init init_dvbdev(void)
{
	int retval;
	dev_t dev = MKDEV(DVB_MAJOR, 0);
	printk(KERN_ERR "WARNING: You are using an experimental version of the media stack.\n\tAs the driver is backported to an older kernel, it doesn't offer\n\tenough quality for its usage in production.\n\tUse it with care.\nLatest git patches (needed if you report a bug to linux-media@vger.kernel.org):\n\tdfb9f94e8e5e7f73c8e2bcb7d4fb1de57e7c333d [media] stk1160: Build as a module if SND is m and audio support is selected\n\t9f1595245574a2dc1fb375df665e4d9fe336a9c4 [media] cx23885-video: fix two warnings\n\t5bc08e1921e46101457d3be09835697490177fdd [media] cx23885[v4]: Fix interrupt storm when enabling IR receiver\n");

	if ((retval = register_chrdev_region(dev, MAX_DVB_MINORS, "DVB")) != 0) {
		printk(KERN_ERR "dvb-core: unable to get major %d\n", DVB_MAJOR);
		return retval;
	}

	cdev_init(&dvb_device_cdev, &dvb_device_fops);
	if ((retval = cdev_add(&dvb_device_cdev, dev, MAX_DVB_MINORS)) != 0) {
		printk(KERN_ERR "dvb-core: unable register character device\n");
		goto error;
	}

	dvb_class = class_create(THIS_MODULE, "dvb");
	if (IS_ERR(dvb_class)) {
		retval = PTR_ERR(dvb_class);
		goto error;
	}
	dvb_class->dev_uevent = dvb_uevent;
	dvb_class->devnode = dvb_devnode;
	return 0;

error:
	cdev_del(&dvb_device_cdev);
	unregister_chrdev_region(dev, MAX_DVB_MINORS);
	return retval;
}


static void __exit exit_dvbdev(void)
{
	class_destroy(dvb_class);
	cdev_del(&dvb_device_cdev);
	unregister_chrdev_region(MKDEV(DVB_MAJOR, 0), MAX_DVB_MINORS);
}

subsys_initcall(init_dvbdev);
module_exit(exit_dvbdev);

MODULE_DESCRIPTION("DVB Core Driver");
MODULE_AUTHOR("Marcus Metzler, Ralph Metzler, Holger Waechtler");
MODULE_LICENSE("GPL");
