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 list_head *list;
  83         struct snd_device *dev;
  84
  85         snd_assert(card != NULL, return -ENXIO);
  86         snd_assert(device_data != NULL, return -ENXIO);
  87         list_for_each(list, &card->devices) {
  88                 dev = snd_device(list);
  89                 if (dev->device_data != device_data)
  90                         continue;
  91                 /* unlink */
  92                 list_del(&dev->list);
  93                 if (dev->state == SNDRV_DEV_REGISTERED &&
  94                     dev->ops->dev_disconnect)
  95                         if (dev->ops->dev_disconnect(dev))
  96                                 snd_printk(KERN_ERR
  97                                            "device disconnect failure\n");
  98                 if (dev->ops->dev_free) {
  99                         if (dev->ops->dev_free(dev))
 100                                 snd_printk(KERN_ERR "device free failure\n");
 101                 }
 102                 kfree(dev);
 103                 return 0;
 104         }
 105         snd_printd("device free %p (from %p), not found\n", device_data,
 106                    __builtin_return_address(0));
 107         return -ENXIO;
 108 }
 109
 110 EXPORT_SYMBOL(snd_device_free);
 111
 112 /**
 113  * snd_device_disconnect - disconnect the device
 114  * @card: the card instance
 115  * @device_data: the data pointer to disconnect
 116  *
 117  * Turns the device into the disconnection state, invoking
 118  * dev_disconnect callback, if the device was already registered.
 119  *
 120  * Usually called from snd_card_disconnect().
 121  *
 122  * Returns zero if successful, or a negative error code on failure or if the
 123  * device not found.
 124  */
 125 int snd_device_disconnect(struct snd_card *card, void *device_data)
 126 {
 127         struct list_head *list;
 128         struct snd_device *dev;
 129
 130         snd_assert(card != NULL, return -ENXIO);
 131         snd_assert(device_data != NULL, return -ENXIO);
 132         list_for_each(list, &card->devices) {
 133                 dev = snd_device(list);
 134                 if (dev->device_data != device_data)
 135                         continue;
 136                 if (dev->state == SNDRV_DEV_REGISTERED &&
 137                     dev->ops->dev_disconnect) {
 138                         if (dev->ops->dev_disconnect(dev))
 139                                 snd_printk(KERN_ERR "device disconnect failure\n");
 140                         dev->state = SNDRV_DEV_DISCONNECTED;
 141                 }
 142                 return 0;
 143         }
 144         snd_printd("device disconnect %p (from %p), not found\n", device_data,
 145                    __builtin_return_address(0));
 146         return -ENXIO;
 147 }
 148
 149 /**
 150  * snd_device_register - register the device
 151  * @card: the card instance
 152  * @device_data: the data pointer to register
 153  *
 154  * Registers the device which was already created via
 155  * snd_device_new().  Usually this is called from snd_card_register(),
 156  * but it can be called later if any new devices are created after
 157  * invocation of snd_card_register().
 158  *
 159  * Returns zero if successful, or a negative error code on failure or if the
 160  * device not found.
 161  */
 162 int snd_device_register(struct snd_card *card, void *device_data)
 163 {
 164         struct list_head *list;
 165         struct snd_device *dev;
 166         int err;
 167
 168         snd_assert(card != NULL, return -ENXIO);
 169         snd_assert(device_data != NULL, return -ENXIO);
 170         list_for_each(list, &card->devices) {
 171                 dev = snd_device(list);
 172                 if (dev->device_data != device_data)
 173                         continue;
 174                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 175                         if ((err = dev->ops->dev_register(dev)) < 0)
 176                                 return err;
 177                         dev->state = SNDRV_DEV_REGISTERED;
 178                         return 0;
 179                 }
 180                 snd_printd("snd_device_register busy\n");
 181                 return -EBUSY;
 182         }
 183         snd_BUG();
 184         return -ENXIO;
 185 }
 186
 187 EXPORT_SYMBOL(snd_device_register);
 188
 189 /*
 190  * register all the devices on the card.
 191  * called from init.c
 192  */
 193 int snd_device_register_all(struct snd_card *card)
 194 {
 195         struct list_head *list;
 196         struct snd_device *dev;
 197         int err;
 198
 199         snd_assert(card != NULL, return -ENXIO);
 200         list_for_each(list, &card->devices) {
 201                 dev = snd_device(list);
 202                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 203                         if ((err = dev->ops->dev_register(dev)) < 0)
 204                                 return err;
 205                         dev->state = SNDRV_DEV_REGISTERED;
 206                 }
 207         }
 208         return 0;
 209 }
 210
 211 /*
 212  * disconnect all the devices on the card.
 213  * called from init.c
 214  */
 215 int snd_device_disconnect_all(struct snd_card *card)
 216 {
 217         struct snd_device *dev;
 218         struct list_head *list;
 219         int err = 0;
 220
 221         snd_assert(card != NULL, return -ENXIO);
 222         list_for_each(list, &card->devices) {
 223                 dev = snd_device(list);
 224                 if (snd_device_disconnect(card, dev->device_data) < 0)
 225                         err = -ENXIO;
 226         }
 227         return err;
 228 }
 229
 230 /*
 231  * release all the devices on the card.
 232  * called from init.c
 233  */
 234 int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 235 {
 236         struct snd_device *dev;
 237         struct list_head *list;
 238         int err;
 239         unsigned int range_low, range_high;
 240
 241         snd_assert(card != NULL, return -ENXIO);
 242         range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 243         range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 244       __again:
 245         list_for_each(list, &card->devices) {
 246                 dev = snd_device(list);
 247                 if (dev->type >= range_low && dev->type <= range_high) {
 248                         if ((err = snd_device_free(card, dev->device_data)) < 0)
 249                                 return err;
 250                         goto __again;
 251                 }
 252         }
 253         return 0;
 254 }