linux/sound/core/device.c
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   1/*
   2 *  Device management routines
   3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4 *
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21
  22#include <linux/slab.h>
  23#include <linux/time.h>
  24#include <linux/errno.h>
  25#include <sound/core.h>
  26
  27/**
  28 * snd_device_new - create an ALSA device component
  29 * @card: the card instance
  30 * @type: the device type, SNDRV_DEV_XXX
  31 * @device_data: the data pointer of this device
  32 * @ops: the operator table
  33 *
  34 * Creates a new device component for the given data pointer.
  35 * The device will be assigned to the card and managed together
  36 * by the card.
  37 *
  38 * The data pointer plays a role as the identifier, too, so the
  39 * pointer address must be unique and unchanged.
  40 *
  41 * Returns zero if successful, or a negative error code on failure.
  42 */
  43int snd_device_new(struct snd_card *card, snd_device_type_t type,
  44                   void *device_data, struct snd_device_ops *ops)
  45{
  46        struct snd_device *dev;
  47
  48        if (snd_BUG_ON(!card || !device_data || !ops))
  49                return -ENXIO;
  50        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  51        if (dev == NULL) {
  52                snd_printk(KERN_ERR "Cannot allocate device\n");
  53                return -ENOMEM;
  54        }
  55        dev->card = card;
  56        dev->type = type;
  57        dev->state = SNDRV_DEV_BUILD;
  58        dev->device_data = device_data;
  59        dev->ops = ops;
  60        list_add(&dev->list, &card->devices);   /* add to the head of list */
  61        return 0;
  62}
  63
  64EXPORT_SYMBOL(snd_device_new);
  65
  66/**
  67 * snd_device_free - release the device from the card
  68 * @card: the card instance
  69 * @device_data: the data pointer to release
  70 *
  71 * Removes the device from the list on the card and invokes the
  72 * callbacks, dev_disconnect and dev_free, corresponding to the state.
  73 * Then release the device.
  74 *
  75 * Returns zero if successful, or a negative error code on failure or if the
  76 * device not found.
  77 */
  78int snd_device_free(struct snd_card *card, void *device_data)
  79{
  80        struct snd_device *dev;
  81        
  82        if (snd_BUG_ON(!card || !device_data))
  83                return -ENXIO;
  84        list_for_each_entry(dev, &card->devices, list) {
  85                if (dev->device_data != device_data)
  86                        continue;
  87                /* unlink */
  88                list_del(&dev->list);
  89                if (dev->state == SNDRV_DEV_REGISTERED &&
  90                    dev->ops->dev_disconnect)
  91                        if (dev->ops->dev_disconnect(dev))
  92                                snd_printk(KERN_ERR
  93                                           "device disconnect failure\n");
  94                if (dev->ops->dev_free) {
  95                        if (dev->ops->dev_free(dev))
  96                                snd_printk(KERN_ERR "device free failure\n");
  97                }
  98                kfree(dev);
  99                return 0;
 100        }
 101        snd_printd("device free %p (from %pF), not found\n", device_data,
 102                   __builtin_return_address(0));
 103        return -ENXIO;
 104}
 105
 106EXPORT_SYMBOL(snd_device_free);
 107
 108/**
 109 * snd_device_disconnect - disconnect the device
 110 * @card: the card instance
 111 * @device_data: the data pointer to disconnect
 112 *
 113 * Turns the device into the disconnection state, invoking
 114 * dev_disconnect callback, if the device was already registered.
 115 *
 116 * Usually called from snd_card_disconnect().
 117 *
 118 * Returns zero if successful, or a negative error code on failure or if the
 119 * device not found.
 120 */
 121int snd_device_disconnect(struct snd_card *card, void *device_data)
 122{
 123        struct snd_device *dev;
 124
 125        if (snd_BUG_ON(!card || !device_data))
 126                return -ENXIO;
 127        list_for_each_entry(dev, &card->devices, list) {
 128                if (dev->device_data != device_data)
 129                        continue;
 130                if (dev->state == SNDRV_DEV_REGISTERED &&
 131                    dev->ops->dev_disconnect) {
 132                        if (dev->ops->dev_disconnect(dev))
 133                                snd_printk(KERN_ERR "device disconnect failure\n");
 134                        dev->state = SNDRV_DEV_DISCONNECTED;
 135                }
 136                return 0;
 137        }
 138        snd_printd("device disconnect %p (from %pF), not found\n", device_data,
 139                   __builtin_return_address(0));
 140        return -ENXIO;
 141}
 142
 143/**
 144 * snd_device_register - register the device
 145 * @card: the card instance
 146 * @device_data: the data pointer to register
 147 *
 148 * Registers the device which was already created via
 149 * snd_device_new().  Usually this is called from snd_card_register(),
 150 * but it can be called later if any new devices are created after
 151 * invocation of snd_card_register().
 152 *
 153 * Returns zero if successful, or a negative error code on failure or if the
 154 * device not found.
 155 */
 156int snd_device_register(struct snd_card *card, void *device_data)
 157{
 158        struct snd_device *dev;
 159        int err;
 160
 161        if (snd_BUG_ON(!card || !device_data))
 162                return -ENXIO;
 163        list_for_each_entry(dev, &card->devices, list) {
 164                if (dev->device_data != device_data)
 165                        continue;
 166                if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 167                        if ((err = dev->ops->dev_register(dev)) < 0)
 168                                return err;
 169                        dev->state = SNDRV_DEV_REGISTERED;
 170                        return 0;
 171                }
 172                snd_printd("snd_device_register busy\n");
 173                return -EBUSY;
 174        }
 175        snd_BUG();
 176        return -ENXIO;
 177}
 178
 179EXPORT_SYMBOL(snd_device_register);
 180
 181/*
 182 * register all the devices on the card.
 183 * called from init.c
 184 */
 185int snd_device_register_all(struct snd_card *card)
 186{
 187        struct snd_device *dev;
 188        int err;
 189        
 190        if (snd_BUG_ON(!card))
 191                return -ENXIO;
 192        list_for_each_entry(dev, &card->devices, list) {
 193                if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 194                        if ((err = dev->ops->dev_register(dev)) < 0)
 195                                return err;
 196                        dev->state = SNDRV_DEV_REGISTERED;
 197                }
 198        }
 199        return 0;
 200}
 201
 202/*
 203 * disconnect all the devices on the card.
 204 * called from init.c
 205 */
 206int snd_device_disconnect_all(struct snd_card *card)
 207{
 208        struct snd_device *dev;
 209        int err = 0;
 210
 211        if (snd_BUG_ON(!card))
 212                return -ENXIO;
 213        list_for_each_entry(dev, &card->devices, list) {
 214                if (snd_device_disconnect(card, dev->device_data) < 0)
 215                        err = -ENXIO;
 216        }
 217        return err;
 218}
 219
 220/*
 221 * release all the devices on the card.
 222 * called from init.c
 223 */
 224int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 225{
 226        struct snd_device *dev;
 227        int err;
 228        unsigned int range_low, range_high;
 229
 230        if (snd_BUG_ON(!card))
 231                return -ENXIO;
 232        range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 233        range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 234      __again:
 235        list_for_each_entry(dev, &card->devices, list) {
 236                if (dev->type >= range_low && dev->type <= range_high) {
 237                        if ((err = snd_device_free(card, dev->device_data)) < 0)
 238                                return err;
 239                        goto __again;
 240                }
 241        }
 242        return 0;
 243}
 244