sound/core/device.c

   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  */
  43 int 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         snd_assert(card != NULL, return -ENXIO);
  49         snd_assert(device_data != NULL, return -ENXIO);
  50         snd_assert(ops != NULL, return -ENXIO);
  51         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  52         if (dev == NULL) {
  53                 snd_printk(KERN_ERR "Cannot allocate device\n");
  54                 return -ENOMEM;
  55         }
  56         dev->card = card;
  57         dev->type = type;
  58         dev->state = SNDRV_DEV_BUILD;
  59         dev->device_data = device_data;
  60         dev->ops = ops;
  61         list_add(&dev->list, &card->devices);   /* add to the head of list */
  62         return 0;
  63 }
  64
  65 EXPORT_SYMBOL(snd_device_new);
  66
  67 /**
  68  * snd_device_free - release the device from the card
  69  * @card: the card instance
  70  * @device_data: the data pointer to release
  71  *
  72  * Removes the device from the list on the card and invokes the
  73  * callbacks, dev_disconnect and dev_free, corresponding to the state.
  74  * Then release the device.
  75  *
  76  * Returns zero if successful, or a negative error code on failure or if the
  77  * device not found.
  78  */
  79 int snd_device_free(struct snd_card *card, void *device_data)
  80 {
  81         struct snd_device *dev;
  82
  83         snd_assert(card != NULL, return -ENXIO);
  84         snd_assert(device_data != NULL, return -ENXIO);
  85         list_for_each_entry(dev, &card->devices, list) {
  86                 if (dev->device_data != device_data)
  87                         continue;
  88                 /* unlink */
  89                 list_del(&dev->list);
  90                 if (dev->state == SNDRV_DEV_REGISTERED &&
  91                     dev->ops->dev_disconnect)
  92                         if (dev->ops->dev_disconnect(dev))
  93                                 snd_printk(KERN_ERR
  94                                            "device disconnect failure\n");
  95                 if (dev->ops->dev_free) {
  96                         if (dev->ops->dev_free(dev))
  97                                 snd_printk(KERN_ERR "device free failure\n");
  98                 }
  99                 kfree(dev);
 100                 return 0;
 101         }
 102         snd_printd("device free %p (from %p), not found\n", device_data,
 103                    __builtin_return_address(0));
 104         return -ENXIO;
 105 }
 106
 107 EXPORT_SYMBOL(snd_device_free);
 108
 109 /**
 110  * snd_device_disconnect - disconnect the device
 111  * @card: the card instance
 112  * @device_data: the data pointer to disconnect
 113  *
 114  * Turns the device into the disconnection state, invoking
 115  * dev_disconnect callback, if the device was already registered.
 116  *
 117  * Usually called from snd_card_disconnect().
 118  *
 119  * Returns zero if successful, or a negative error code on failure or if the
 120  * device not found.
 121  */
 122 int snd_device_disconnect(struct snd_card *card, void *device_data)
 123 {
 124         struct snd_device *dev;
 125
 126         snd_assert(card != NULL, return -ENXIO);
 127         snd_assert(device_data != NULL, return -ENXIO);
 128         list_for_each_entry(dev, &card->devices, list) {
 129                 if (dev->device_data != device_data)
 130                         continue;
 131                 if (dev->state == SNDRV_DEV_REGISTERED &&
 132                     dev->ops->dev_disconnect) {
 133                         if (dev->ops->dev_disconnect(dev))
 134                                 snd_printk(KERN_ERR "device disconnect failure\n");
 135                         dev->state = SNDRV_DEV_DISCONNECTED;
 136                 }
 137                 return 0;
 138         }
 139         snd_printd("device disconnect %p (from %p), not found\n", device_data,
 140                    __builtin_return_address(0));
 141         return -ENXIO;
 142 }
 143
 144 /**
 145  * snd_device_register - register the device
 146  * @card: the card instance
 147  * @device_data: the data pointer to register
 148  *
 149  * Registers the device which was already created via
 150  * snd_device_new().  Usually this is called from snd_card_register(),
 151  * but it can be called later if any new devices are created after
 152  * invocation of snd_card_register().
 153  *
 154  * Returns zero if successful, or a negative error code on failure or if the
 155  * device not found.
 156  */
 157 int snd_device_register(struct snd_card *card, void *device_data)
 158 {
 159         struct snd_device *dev;
 160         int err;
 161
 162         snd_assert(card != NULL, return -ENXIO);
 163         snd_assert(device_data != NULL, return -ENXIO);
 164         list_for_each_entry(dev, &card->devices, list) {
 165                 if (dev->device_data != device_data)
 166                         continue;
 167                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 168                         if ((err = dev->ops->dev_register(dev)) < 0)
 169                                 return err;
 170                         dev->state = SNDRV_DEV_REGISTERED;
 171                         return 0;
 172                 }
 173                 snd_printd("snd_device_register busy\n");
 174                 return -EBUSY;
 175         }
 176         snd_BUG();
 177         return -ENXIO;
 178 }
 179
 180 EXPORT_SYMBOL(snd_device_register);
 181
 182 /*
 183  * register all the devices on the card.
 184  * called from init.c
 185  */
 186 int snd_device_register_all(struct snd_card *card)
 187 {
 188         struct snd_device *dev;
 189         int err;
 190
 191         snd_assert(card != NULL, 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  */
 206 int snd_device_disconnect_all(struct snd_card *card)
 207 {
 208         struct snd_device *dev;
 209         int err = 0;
 210
 211         snd_assert(card != NULL, return -ENXIO);
 212         list_for_each_entry(dev, &card->devices, list) {
 213                 if (snd_device_disconnect(card, dev->device_data) < 0)
 214                         err = -ENXIO;
 215         }
 216         return err;
 217 }
 218
 219 /*
 220  * release all the devices on the card.
 221  * called from init.c
 222  */
 223 int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 224 {
 225         struct snd_device *dev;
 226         int err;
 227         unsigned int range_low, range_high;
 228
 229         snd_assert(card != NULL, return -ENXIO);
 230         range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 231         range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 232       __again:
 233         list_for_each_entry(dev, &card->devices, list) {
 234                 if (dev->type >= range_low && dev->type <= range_high) {
 235                         if ((err = snd_device_free(card, dev->device_data)) < 0)
 236                                 return err;
 237                         goto __again;
 238                 }
 239         }
 240         return 0;
 241 }