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 == NULL) {
  54                 dev_err(card->dev, "Cannot allocate device, type=%d\n", type);
  55                 return -ENOMEM;
  56         }
  57         INIT_LIST_HEAD(&dev->list);
  58         dev->card = card;
  59         dev->type = type;
  60         dev->state = SNDRV_DEV_BUILD;
  61         dev->device_data = device_data;
  62         dev->ops = ops;
  63
  64         /* insert the entry in an incrementally sorted list */
  65         list_for_each_prev(p, &card->devices) {
  66                 struct snd_device *pdev = list_entry(p, struct snd_device, list);
  67                 if ((unsigned int)pdev->type <= (unsigned int)type)
  68                         break;
  69         }
  70
  71         list_add(&dev->list, p);
  72         return 0;
  73 }
  74 EXPORT_SYMBOL(snd_device_new);
  75
  76 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
  77 {
  78         struct snd_device *dev;
  79
  80         list_for_each_entry(dev, &card->devices, list)
  81                 if (dev->device_data == device_data)
  82                         return dev;
  83
  84         return NULL;
  85 }
  86
  87 /**
  88  * snd_device_free - release the device from the card
  89  * @card: the card instance
  90  * @device_data: the data pointer to release
  91  *
  92  * Removes the device from the list on the card and invokes the
  93  * callbacks, dev_disconnect and dev_free, corresponding to the state.
  94  * Then release the device.
  95  *
  96  * Return: Zero if successful, or a negative error code on failure or if the
  97  * device not found.
  98  */
  99 int snd_device_free(struct snd_card *card, void *device_data)
 100 {
 101         struct snd_device *dev;
 102
 103         if (snd_BUG_ON(!card || !device_data))
 104                 return -ENXIO;
 105         dev = look_for_dev(card, device_data);
 106         if (dev) {
 107                 /* unlink */
 108                 list_del(&dev->list);
 109                 if (dev->state == SNDRV_DEV_REGISTERED &&
 110                     dev->ops->dev_disconnect)
 111                         if (dev->ops->dev_disconnect(dev))
 112                                 dev_err(card->dev,
 113                                         "device disconnect failure\n");
 114                 if (dev->ops->dev_free) {
 115                         if (dev->ops->dev_free(dev))
 116                                 dev_err(card->dev, "device free failure\n");
 117                 }
 118                 kfree(dev);
 119                 return 0;
 120         }
 121         dev_dbg(card->dev, "device free %p (from %pF), not found\n",
 122                 device_data, __builtin_return_address(0));
 123         return -ENXIO;
 124 }
 125 EXPORT_SYMBOL(snd_device_free);
 126
 127 /**
 128  * snd_device_disconnect - disconnect the device
 129  * @card: the card instance
 130  * @device_data: the data pointer to disconnect
 131  *
 132  * Turns the device into the disconnection state, invoking
 133  * dev_disconnect callback, if the device was already registered.
 134  *
 135  * Usually called from snd_card_disconnect().
 136  *
 137  * Return: Zero if successful, or a negative error code on failure or if the
 138  * device not found.
 139  */
 140 int snd_device_disconnect(struct snd_card *card, void *device_data)
 141 {
 142         struct snd_device *dev;
 143
 144         if (snd_BUG_ON(!card || !device_data))
 145                 return -ENXIO;
 146         dev = look_for_dev(card, device_data);
 147         if (dev) {
 148                 if (dev->state == SNDRV_DEV_REGISTERED &&
 149                     dev->ops->dev_disconnect) {
 150                         if (dev->ops->dev_disconnect(dev))
 151                                 dev_err(card->dev,
 152                                         "device disconnect failure\n");
 153                         dev->state = SNDRV_DEV_DISCONNECTED;
 154                 }
 155                 return 0;
 156         }
 157         dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
 158                 device_data, __builtin_return_address(0));
 159         return -ENXIO;
 160 }
 161
 162 /**
 163  * snd_device_register - register the device
 164  * @card: the card instance
 165  * @device_data: the data pointer to register
 166  *
 167  * Registers the device which was already created via
 168  * snd_device_new().  Usually this is called from snd_card_register(),
 169  * but it can be called later if any new devices are created after
 170  * invocation of snd_card_register().
 171  *
 172  * Return: Zero if successful, or a negative error code on failure or if the
 173  * device not found.
 174  */
 175 int snd_device_register(struct snd_card *card, void *device_data)
 176 {
 177         struct snd_device *dev;
 178         int err;
 179
 180         if (snd_BUG_ON(!card || !device_data))
 181                 return -ENXIO;
 182         dev = look_for_dev(card, device_data);
 183         if (dev) {
 184                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 185                         if ((err = dev->ops->dev_register(dev)) < 0)
 186                                 return err;
 187                         dev->state = SNDRV_DEV_REGISTERED;
 188                         return 0;
 189                 }
 190                 dev_dbg(card->dev, "snd_device_register busy\n");
 191                 return -EBUSY;
 192         }
 193         snd_BUG();
 194         return -ENXIO;
 195 }
 196 EXPORT_SYMBOL(snd_device_register);
 197
 198 /*
 199  * register all the devices on the card.
 200  * called from init.c
 201  */
 202 int snd_device_register_all(struct snd_card *card)
 203 {
 204         struct snd_device *dev;
 205         int err;
 206
 207         if (snd_BUG_ON(!card))
 208                 return -ENXIO;
 209         list_for_each_entry(dev, &card->devices, list) {
 210                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 211                         if ((err = dev->ops->dev_register(dev)) < 0)
 212                                 return err;
 213                         dev->state = SNDRV_DEV_REGISTERED;
 214                 }
 215         }
 216         return 0;
 217 }
 218
 219 /*
 220  * disconnect all the devices on the card.
 221  * called from init.c
 222  */
 223 int snd_device_disconnect_all(struct snd_card *card)
 224 {
 225         struct snd_device *dev;
 226         int err = 0;
 227
 228         if (snd_BUG_ON(!card))
 229                 return -ENXIO;
 230         list_for_each_entry_reverse(dev, &card->devices, list) {
 231                 if (snd_device_disconnect(card, dev->device_data) < 0)
 232                         err = -ENXIO;
 233         }
 234         return err;
 235 }
 236
 237 /*
 238  * release all the devices on the card.
 239  * called from init.c
 240  */
 241 int snd_device_free_all(struct snd_card *card)
 242 {
 243         struct snd_device *dev, *next;
 244         int ret = 0;
 245
 246         if (snd_BUG_ON(!card))
 247                 return -ENXIO;
 248         list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
 249                 int err = snd_device_free(card, dev->device_data);
 250                 if (err < 0)
 251                         ret = err;
 252         }
 253         return ret;
 254 }