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         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
  64 EXPORT_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  */
  78 int 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 %p), not found\n", device_data,
 102                    __builtin_return_address(0));
 103         return -ENXIO;
 104 }
 105
 106 EXPORT_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  */
 121 int 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 %p), 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  */
 156 int 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
 179 EXPORT_SYMBOL(snd_device_register);
 180
 181 /*
 182  * register all the devices on the card.
 183  * called from init.c
 184  */
 185 int 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  */
 206 int 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  */
 224 int 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 }