sound/core/device.c

   1 /*
   2  *  Device management routines
   3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
  23 #include <linux/slab.h>
  24 #include <linux/time.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  * Returns zero if successful, or a negative error code on failure.
  43  */
  44 int snd_device_new(struct snd_card *card, snd_device_type_t type,
  45                    void *device_data, struct snd_device_ops *ops)
  46 {
  47         struct snd_device *dev;
  48
  49         snd_assert(card != NULL, return -ENXIO);
  50         snd_assert(device_data != NULL, return -ENXIO);
  51         snd_assert(ops != NULL, return -ENXIO);
  52         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  53         if (dev == NULL) {
  54                 snd_printk(KERN_ERR "Cannot allocate device\n");
  55                 return -ENOMEM;
  56         }
  57         dev->card = card;
  58         dev->type = type;
  59         dev->state = SNDRV_DEV_BUILD;
  60         dev->device_data = device_data;
  61         dev->ops = ops;
  62         list_add(&dev->list, &card->devices);   /* add to the head of list */
  63         return 0;
  64 }
  65
  66 EXPORT_SYMBOL(snd_device_new);
  67
  68 /**
  69  * snd_device_free - release the device from the card
  70  * @card: the card instance
  71  * @device_data: the data pointer to release
  72  *
  73  * Removes the device from the list on the card and invokes the
  74  * callbacks, dev_disconnect and dev_free, corresponding to the state.
  75  * Then release the device.
  76  *
  77  * Returns zero if successful, or a negative error code on failure or if the
  78  * device not found.
  79  */
  80 int snd_device_free(struct snd_card *card, void *device_data)
  81 {
  82         struct snd_device *dev;
  83
  84         snd_assert(card != NULL, return -ENXIO);
  85         snd_assert(device_data != NULL, return -ENXIO);
  86         list_for_each_entry(dev, &card->devices, list) {
  87                 if (dev->device_data != device_data)
  88                         continue;
  89                 /* unlink */
  90                 list_del(&dev->list);
  91                 if (dev->state == SNDRV_DEV_REGISTERED &&
  92                     dev->ops->dev_disconnect)
  93                         if (dev->ops->dev_disconnect(dev))
  94                                 snd_printk(KERN_ERR
  95                                            "device disconnect failure\n");
  96                 if (dev->ops->dev_free) {
  97                         if (dev->ops->dev_free(dev))
  98                                 snd_printk(KERN_ERR "device free failure\n");
  99                 }
 100                 kfree(dev);
 101                 return 0;
 102         }
 103         snd_printd("device free %p (from %p), not found\n", device_data,
 104                    __builtin_return_address(0));
 105         return -ENXIO;
 106 }
 107
 108 EXPORT_SYMBOL(snd_device_free);
 109
 110 /**
 111  * snd_device_disconnect - disconnect the device
 112  * @card: the card instance
 113  * @device_data: the data pointer to disconnect
 114  *
 115  * Turns the device into the disconnection state, invoking
 116  * dev_disconnect callback, if the device was already registered.
 117  *
 118  * Usually called from snd_card_disconnect().
 119  *
 120  * Returns zero if successful, or a negative error code on failure or if the
 121  * device not found.
 122  */
 123 int snd_device_disconnect(struct snd_card *card, void *device_data)
 124 {
 125         struct snd_device *dev;
 126
 127         snd_assert(card != NULL, return -ENXIO);
 128         snd_assert(device_data != NULL, return -ENXIO);
 129         list_for_each_entry(dev, &card->devices, list) {
 130                 if (dev->device_data != device_data)
 131                         continue;
 132                 if (dev->state == SNDRV_DEV_REGISTERED &&
 133                     dev->ops->dev_disconnect) {
 134                         if (dev->ops->dev_disconnect(dev))
 135                                 snd_printk(KERN_ERR "device disconnect failure\n");
 136                         dev->state = SNDRV_DEV_DISCONNECTED;
 137                 }
 138                 return 0;
 139         }
 140         snd_printd("device disconnect %p (from %p), not found\n", device_data,
 141                    __builtin_return_address(0));
 142         return -ENXIO;
 143 }
 144
 145 /**
 146  * snd_device_register - register the device
 147  * @card: the card instance
 148  * @device_data: the data pointer to register
 149  *
 150  * Registers the device which was already created via
 151  * snd_device_new().  Usually this is called from snd_card_register(),
 152  * but it can be called later if any new devices are created after
 153  * invocation of snd_card_register().
 154  *
 155  * Returns zero if successful, or a negative error code on failure or if the
 156  * device not found.
 157  */
 158 int snd_device_register(struct snd_card *card, void *device_data)
 159 {
 160         struct snd_device *dev;
 161         int err;
 162
 163         snd_assert(card != NULL, return -ENXIO);
 164         snd_assert(device_data != NULL, return -ENXIO);
 165         list_for_each_entry(dev, &card->devices, list) {
 166                 if (dev->device_data != device_data)
 167                         continue;
 168                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 169                         if ((err = dev->ops->dev_register(dev)) < 0)
 170                                 return err;
 171                         dev->state = SNDRV_DEV_REGISTERED;
 172                         return 0;
 173                 }
 174                 snd_printd("snd_device_register busy\n");
 175                 return -EBUSY;
 176         }
 177         snd_BUG();
 178         return -ENXIO;
 179 }
 180
 181 EXPORT_SYMBOL(snd_device_register);
 182
 183 /*
 184  * register all the devices on the card.
 185  * called from init.c
 186  */
 187 int snd_device_register_all(struct snd_card *card)
 188 {
 189         struct snd_device *dev;
 190         int err;
 191
 192         snd_assert(card != NULL, return -ENXIO);
 193         list_for_each_entry(dev, &card->devices, list) {
 194                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 195                         if ((err = dev->ops->dev_register(dev)) < 0)
 196                                 return err;
 197                         dev->state = SNDRV_DEV_REGISTERED;
 198                 }
 199         }
 200         return 0;
 201 }
 202
 203 /*
 204  * disconnect all the devices on the card.
 205  * called from init.c
 206  */
 207 int snd_device_disconnect_all(struct snd_card *card)
 208 {
 209         struct snd_device *dev;
 210         int err = 0;
 211
 212         snd_assert(card != NULL, 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         snd_assert(card != NULL, return -ENXIO);
 231         range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 232         range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 233       __again:
 234         list_for_each_entry(dev, &card->devices, list) {
 235                 if (dev->type >= range_low && dev->type <= range_high) {
 236                         if ((err = snd_device_free(card, dev->device_data)) < 0)
 237                                 return err;
 238                         goto __again;
 239                 }
 240         }
 241         return 0;
 242 }