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dvbdev.c

/*
 * 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 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"
};

#define DVB_MAX_ADAPTERS      8
#define DVB_MAX_IDS           4
#define nums2minor(num,type,id)     ((num << 6) | (id << 4) | type)
#define MAX_DVB_MINORS        (DVB_MAX_ADAPTERS*64)

static struct class *dvb_class;

static struct dvb_device* dvbdev_find_device (int minor)
{
      struct dvb_adapter *adap;

      list_for_each_entry(adap, &dvb_adapter_list, list_head) {
            struct dvb_device *dev;
            list_for_each_entry(dev, &adap->device_list, list_head)
                  if (nums2minor(adap->num, dev->type, dev->id) == minor)
                        return dev;
      }

      return NULL;
}


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

      dvbdev = dvbdev_find_device (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->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);
            return err;
      }
      return -ENODEV;
}


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

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);


int dvb_generic_ioctl(struct inode *inode, 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 (inode, 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 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", __FUNCTION__);
            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(dvbdev->fops, template->fops, sizeof(struct file_operations));
      dvbdev->fops->owner = adap->module;

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

      mutex_unlock(&dvbdev_register_lock);

      clsdev = device_create(dvb_class, adap->device,
                         MKDEV(DVB_MAJOR, nums2minor(adap->num, type, id)),
                         "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",
                   __FUNCTION__, 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, nums2minor(adap->num, type, id),
            nums2minor(adap->num, type, id));

      return 0;
}
EXPORT_SYMBOL(dvb_register_device);


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

      device_destroy(dvb_class, MKDEV(DVB_MAJOR, nums2minor(dvbdev->adapter->num,
                   dvbdev->type, dvbdev->id)));

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


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

      while (num < DVB_MAX_ADAPTERS) {
            struct dvb_adapter *adap;
            list_for_each_entry(adap, &dvb_adapter_list, list_head)
                  if (adap->num == num)
                        goto skip;
            return num;
skip:
            num++;
      }

      return -ENFILE;
}


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

      mutex_lock(&dvbdev_register_lock);

      if ((num = dvbdev_get_free_adapter_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;

      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 inode *inode, struct file *file,
                 unsigned int cmd, unsigned long arg,
                 int (*func)(struct inode *inode, 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(inode, file, cmd, parg)) == -ENOIOCTLCMD)
            err = -EINVAL;

      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 __init init_dvbdev(void)
{
      int retval;
      dev_t dev = MKDEV(DVB_MAJOR, 0);

      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;
      }
      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");

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