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/export.h>
  25 #include <linux/errno.h>
  26 #include <sound/core.h>
  27
  28 /**
  29  * snd_device_new - create an ALSA device component
  30  * @card: the card instance
  31  * @type: the device type, SNDRV_DEV_XXX
  32  * @device_data: the data pointer of this device
  33  * @ops: the operator table
  34  *
  35  * Creates a new device component for the given data pointer.
  36  * The device will be assigned to the card and managed together
  37  * by the card.
  38  *
  39  * The data pointer plays a role as the identifier, too, so the
  40  * pointer address must be unique and unchanged.
  41  *
  42  * Return: Zero if successful, or a negative error code on failure.
  43  */
  44 int snd_device_new(struct snd_card *card, enum snd_device_type type,
  45                    void *device_data, struct snd_device_ops *ops)
  46 {
  47         struct snd_device *dev;
  48         struct list_head *p;
  49
  50         if (snd_BUG_ON(!card || !device_data || !ops))
  51                 return -ENXIO;
  52         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  53         if (!dev)
  54                 return -ENOMEM;
  55         INIT_LIST_HEAD(&dev->list);
  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
  62         /* insert the entry in an incrementally sorted list */
  63         list_for_each_prev(p, &card->devices) {
  64                 struct snd_device *pdev = list_entry(p, struct snd_device, list);
  65                 if ((unsigned int)pdev->type <= (unsigned int)type)
  66                         break;
  67         }
  68
  69         list_add(&dev->list, p);
  70         return 0;
  71 }
  72 EXPORT_SYMBOL(snd_device_new);
  73
  74 static void __snd_device_disconnect(struct snd_device *dev)
  75 {
  76         if (dev->state == SNDRV_DEV_REGISTERED) {
  77                 if (dev->ops->dev_disconnect &&
  78                     dev->ops->dev_disconnect(dev))
  79                         dev_err(dev->card->dev, "device disconnect failure\n");
  80                 dev->state = SNDRV_DEV_DISCONNECTED;
  81         }
  82 }
  83
  84 static void __snd_device_free(struct snd_device *dev)
  85 {
  86         /* unlink */
  87         list_del(&dev->list);
  88
  89         __snd_device_disconnect(dev);
  90         if (dev->ops->dev_free) {
  91                 if (dev->ops->dev_free(dev))
  92                         dev_err(dev->card->dev, "device free failure\n");
  93         }
  94         kfree(dev);
  95 }
  96
  97 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
  98 {
  99         struct snd_device *dev;
 100
 101         list_for_each_entry(dev, &card->devices, list)
 102                 if (dev->device_data == device_data)
 103                         return dev;
 104
 105         return NULL;
 106 }
 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  * Return: Zero if successful, or a negative error code on failure or if the
 119  * device not found.
 120  */
 121 void 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;
 127         dev = look_for_dev(card, device_data);
 128         if (dev)
 129                 __snd_device_disconnect(dev);
 130         else
 131                 dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
 132                         device_data, __builtin_return_address(0));
 133 }
 134 EXPORT_SYMBOL_GPL(snd_device_disconnect);
 135
 136 /**
 137  * snd_device_free - release the device from the card
 138  * @card: the card instance
 139  * @device_data: the data pointer to release
 140  *
 141  * Removes the device from the list on the card and invokes the
 142  * callbacks, dev_disconnect and dev_free, corresponding to the state.
 143  * Then release the device.
 144  */
 145 void snd_device_free(struct snd_card *card, void *device_data)
 146 {
 147         struct snd_device *dev;
 148
 149         if (snd_BUG_ON(!card || !device_data))
 150                 return;
 151         dev = look_for_dev(card, device_data);
 152         if (dev)
 153                 __snd_device_free(dev);
 154         else
 155                 dev_dbg(card->dev, "device free %p (from %pF), not found\n",
 156                         device_data, __builtin_return_address(0));
 157 }
 158 EXPORT_SYMBOL(snd_device_free);
 159
 160 static int __snd_device_register(struct snd_device *dev)
 161 {
 162         if (dev->state == SNDRV_DEV_BUILD) {
 163                 if (dev->ops->dev_register) {
 164                         int err = dev->ops->dev_register(dev);
 165                         if (err < 0)
 166                                 return err;
 167                 }
 168                 dev->state = SNDRV_DEV_REGISTERED;
 169         }
 170         return 0;
 171 }
 172
 173 /**
 174  * snd_device_register - register the device
 175  * @card: the card instance
 176  * @device_data: the data pointer to register
 177  *
 178  * Registers the device which was already created via
 179  * snd_device_new().  Usually this is called from snd_card_register(),
 180  * but it can be called later if any new devices are created after
 181  * invocation of snd_card_register().
 182  *
 183  * Return: Zero if successful, or a negative error code on failure or if the
 184  * device not found.
 185  */
 186 int snd_device_register(struct snd_card *card, void *device_data)
 187 {
 188         struct snd_device *dev;
 189
 190         if (snd_BUG_ON(!card || !device_data))
 191                 return -ENXIO;
 192         dev = look_for_dev(card, device_data);
 193         if (dev)
 194                 return __snd_device_register(dev);
 195         snd_BUG();
 196         return -ENXIO;
 197 }
 198 EXPORT_SYMBOL(snd_device_register);
 199
 200 /*
 201  * register all the devices on the card.
 202  * called from init.c
 203  */
 204 int snd_device_register_all(struct snd_card *card)
 205 {
 206         struct snd_device *dev;
 207         int err;
 208
 209         if (snd_BUG_ON(!card))
 210                 return -ENXIO;
 211         list_for_each_entry(dev, &card->devices, list) {
 212                 err = __snd_device_register(dev);
 213                 if (err < 0)
 214                         return err;
 215         }
 216         return 0;
 217 }
 218
 219 /*
 220  * disconnect all the devices on the card.
 221  * called from init.c
 222  */
 223 void snd_device_disconnect_all(struct snd_card *card)
 224 {
 225         struct snd_device *dev;
 226
 227         if (snd_BUG_ON(!card))
 228                 return;
 229         list_for_each_entry_reverse(dev, &card->devices, list)
 230                 __snd_device_disconnect(dev);
 231 }
 232
 233 /*
 234  * release all the devices on the card.
 235  * called from init.c
 236  */
 237 void snd_device_free_all(struct snd_card *card)
 238 {
 239         struct snd_device *dev, *next;
 240
 241         if (snd_BUG_ON(!card))
 242                 return;
 243         list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
 244                 __snd_device_free(dev);
 245 }