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device.c

/*
 *  Device management routines
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   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, 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 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/slab.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <sound/core.h>

/**
 * snd_device_new - create an ALSA device component
 * @card: the card instance
 * @type: the device type, SNDRV_DEV_XXX
 * @device_data: the data pointer of this device
 * @ops: the operator table
 *
 * Creates a new device component for the given data pointer.
 * The device will be assigned to the card and managed together
 * by the card.
 *
 * The data pointer plays a role as the identifier, too, so the
 * pointer address must be unique and unchanged.
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_device_new(struct snd_card *card, snd_device_type_t type,
               void *device_data, struct snd_device_ops *ops)
{
      struct snd_device *dev;

      if (snd_BUG_ON(!card || !device_data || !ops))
            return -ENXIO;
      dev = kzalloc(sizeof(*dev), GFP_KERNEL);
      if (dev == NULL) {
            snd_printk(KERN_ERR "Cannot allocate device\n");
            return -ENOMEM;
      }
      dev->card = card;
      dev->type = type;
      dev->state = SNDRV_DEV_BUILD;
      dev->device_data = device_data;
      dev->ops = ops;
      list_add(&dev->list, &card->devices);     /* add to the head of list */
      return 0;
}

EXPORT_SYMBOL(snd_device_new);

/**
 * snd_device_free - release the device from the card
 * @card: the card instance
 * @device_data: the data pointer to release
 *
 * Removes the device from the list on the card and invokes the
 * callbacks, dev_disconnect and dev_free, corresponding to the state.
 * Then release the device.
 *
 * Returns zero if successful, or a negative error code on failure or if the
 * device not found.
 */
int snd_device_free(struct snd_card *card, void *device_data)
{
      struct snd_device *dev;
      
      if (snd_BUG_ON(!card || !device_data))
            return -ENXIO;
      list_for_each_entry(dev, &card->devices, list) {
            if (dev->device_data != device_data)
                  continue;
            /* unlink */
            list_del(&dev->list);
            if (dev->state == SNDRV_DEV_REGISTERED &&
                dev->ops->dev_disconnect)
                  if (dev->ops->dev_disconnect(dev))
                        snd_printk(KERN_ERR
                                 "device disconnect failure\n");
            if (dev->ops->dev_free) {
                  if (dev->ops->dev_free(dev))
                        snd_printk(KERN_ERR "device free failure\n");
            }
            kfree(dev);
            return 0;
      }
      snd_printd("device free %p (from %pF), not found\n", device_data,
               __builtin_return_address(0));
      return -ENXIO;
}

EXPORT_SYMBOL(snd_device_free);

/**
 * snd_device_disconnect - disconnect the device
 * @card: the card instance
 * @device_data: the data pointer to disconnect
 *
 * Turns the device into the disconnection state, invoking
 * dev_disconnect callback, if the device was already registered.
 *
 * Usually called from snd_card_disconnect().
 *
 * Returns zero if successful, or a negative error code on failure or if the
 * device not found.
 */
int snd_device_disconnect(struct snd_card *card, void *device_data)
{
      struct snd_device *dev;

      if (snd_BUG_ON(!card || !device_data))
            return -ENXIO;
      list_for_each_entry(dev, &card->devices, list) {
            if (dev->device_data != device_data)
                  continue;
            if (dev->state == SNDRV_DEV_REGISTERED &&
                dev->ops->dev_disconnect) {
                  if (dev->ops->dev_disconnect(dev))
                        snd_printk(KERN_ERR "device disconnect failure\n");
                  dev->state = SNDRV_DEV_DISCONNECTED;
            }
            return 0;
      }
      snd_printd("device disconnect %p (from %pF), not found\n", device_data,
               __builtin_return_address(0));
      return -ENXIO;
}

/**
 * snd_device_register - register the device
 * @card: the card instance
 * @device_data: the data pointer to register
 *
 * Registers the device which was already created via
 * snd_device_new().  Usually this is called from snd_card_register(),
 * but it can be called later if any new devices are created after
 * invocation of snd_card_register().
 *
 * Returns zero if successful, or a negative error code on failure or if the
 * device not found.
 */
int snd_device_register(struct snd_card *card, void *device_data)
{
      struct snd_device *dev;
      int err;

      if (snd_BUG_ON(!card || !device_data))
            return -ENXIO;
      list_for_each_entry(dev, &card->devices, list) {
            if (dev->device_data != device_data)
                  continue;
            if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
                  if ((err = dev->ops->dev_register(dev)) < 0)
                        return err;
                  dev->state = SNDRV_DEV_REGISTERED;
                  return 0;
            }
            snd_printd("snd_device_register busy\n");
            return -EBUSY;
      }
      snd_BUG();
      return -ENXIO;
}

EXPORT_SYMBOL(snd_device_register);

/*
 * register all the devices on the card.
 * called from init.c
 */
int snd_device_register_all(struct snd_card *card)
{
      struct snd_device *dev;
      int err;
      
      if (snd_BUG_ON(!card))
            return -ENXIO;
      list_for_each_entry(dev, &card->devices, list) {
            if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
                  if ((err = dev->ops->dev_register(dev)) < 0)
                        return err;
                  dev->state = SNDRV_DEV_REGISTERED;
            }
      }
      return 0;
}

/*
 * disconnect all the devices on the card.
 * called from init.c
 */
int snd_device_disconnect_all(struct snd_card *card)
{
      struct snd_device *dev;
      int err = 0;

      if (snd_BUG_ON(!card))
            return -ENXIO;
      list_for_each_entry(dev, &card->devices, list) {
            if (snd_device_disconnect(card, dev->device_data) < 0)
                  err = -ENXIO;
      }
      return err;
}

/*
 * release all the devices on the card.
 * called from init.c
 */
int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
{
      struct snd_device *dev;
      int err;
      unsigned int range_low, range_high;

      if (snd_BUG_ON(!card))
            return -ENXIO;
      range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
      range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
      __again:
      list_for_each_entry(dev, &card->devices, list) {
            if (dev->type >= range_low && dev->type <= range_high) {
                  if ((err = snd_device_free(card, dev->device_data)) < 0)
                        return err;
                  goto __again;
            }
      }
      return 0;
}

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