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  * callback, dev_unregister or 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->state == SNDRV_DEV_DISCONNECTED) &&
  95                     dev->ops->dev_unregister) {
  96                         if (dev->ops->dev_unregister(dev))
  97                                 snd_printk(KERN_ERR "device unregister failure\n");
  98                 } else {
  99                         if (dev->ops->dev_free) {
 100                                 if (dev->ops->dev_free(dev))
 101                                         snd_printk(KERN_ERR "device free failure\n");
 102                         }
 103                 }
 104                 kfree(dev);
 105                 return 0;
 106         }
 107         snd_printd("device free %p (from %p), not found\n", device_data,
 108                    __builtin_return_address(0));
 109         return -ENXIO;
 110 }
 111
 112 EXPORT_SYMBOL(snd_device_free);
 113
 114 /**
 115  * snd_device_disconnect - disconnect the device
 116  * @card: the card instance
 117  * @device_data: the data pointer to disconnect
 118  *
 119  * Turns the device into the disconnection state, invoking
 120  * dev_disconnect callback, if the device was already registered.
 121  *
 122  * Usually called from snd_card_disconnect().
 123  *
 124  * Returns zero if successful, or a negative error code on failure or if the
 125  * device not found.
 126  */
 127 int snd_device_disconnect(struct snd_card *card, void *device_data)
 128 {
 129         struct list_head *list;
 130         struct snd_device *dev;
 131
 132         snd_assert(card != NULL, return -ENXIO);
 133         snd_assert(device_data != NULL, return -ENXIO);
 134         list_for_each(list, &card->devices) {
 135                 dev = snd_device(list);
 136                 if (dev->device_data != device_data)
 137                         continue;
 138                 if (dev->state == SNDRV_DEV_REGISTERED &&
 139                     dev->ops->dev_disconnect) {
 140                         if (dev->ops->dev_disconnect(dev))
 141                                 snd_printk(KERN_ERR "device disconnect failure\n");
 142                         dev->state = SNDRV_DEV_DISCONNECTED;
 143                 }
 144                 return 0;
 145         }
 146         snd_printd("device disconnect %p (from %p), not found\n", device_data,
 147                    __builtin_return_address(0));
 148         return -ENXIO;
 149 }
 150
 151 /**
 152  * snd_device_register - register the device
 153  * @card: the card instance
 154  * @device_data: the data pointer to register
 155  *
 156  * Registers the device which was already created via
 157  * snd_device_new().  Usually this is called from snd_card_register(),
 158  * but it can be called later if any new devices are created after
 159  * invocation of snd_card_register().
 160  *
 161  * Returns zero if successful, or a negative error code on failure or if the
 162  * device not found.
 163  */
 164 int snd_device_register(struct snd_card *card, void *device_data)
 165 {
 166         struct list_head *list;
 167         struct snd_device *dev;
 168         int err;
 169
 170         snd_assert(card != NULL, return -ENXIO);
 171         snd_assert(device_data != NULL, return -ENXIO);
 172         list_for_each(list, &card->devices) {
 173                 dev = snd_device(list);
 174                 if (dev->device_data != device_data)
 175                         continue;
 176                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 177                         if ((err = dev->ops->dev_register(dev)) < 0)
 178                                 return err;
 179                         dev->state = SNDRV_DEV_REGISTERED;
 180                         return 0;
 181                 }
 182                 snd_printd("snd_device_register busy\n");
 183                 return -EBUSY;
 184         }
 185         snd_BUG();
 186         return -ENXIO;
 187 }
 188
 189 EXPORT_SYMBOL(snd_device_register);
 190
 191 /*
 192  * register all the devices on the card.
 193  * called from init.c
 194  */
 195 int snd_device_register_all(struct snd_card *card)
 196 {
 197         struct list_head *list;
 198         struct snd_device *dev;
 199         int err;
 200
 201         snd_assert(card != NULL, return -ENXIO);
 202         list_for_each(list, &card->devices) {
 203                 dev = snd_device(list);
 204                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 205                         if ((err = dev->ops->dev_register(dev)) < 0)
 206                                 return err;
 207                         dev->state = SNDRV_DEV_REGISTERED;
 208                 }
 209         }
 210         return 0;
 211 }
 212
 213 /*
 214  * disconnect all the devices on the card.
 215  * called from init.c
 216  */
 217 int snd_device_disconnect_all(struct snd_card *card)
 218 {
 219         struct snd_device *dev;
 220         struct list_head *list;
 221         int err = 0;
 222
 223         snd_assert(card != NULL, return -ENXIO);
 224         list_for_each(list, &card->devices) {
 225                 dev = snd_device(list);
 226                 if (snd_device_disconnect(card, dev->device_data) < 0)
 227                         err = -ENXIO;
 228         }
 229         return err;
 230 }
 231
 232 /*
 233  * release all the devices on the card.
 234  * called from init.c
 235  */
 236 int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 237 {
 238         struct snd_device *dev;
 239         struct list_head *list;
 240         int err;
 241         unsigned int range_low, range_high;
 242
 243         snd_assert(card != NULL, return -ENXIO);
 244         range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 245         range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 246       __again:
 247         list_for_each(list, &card->devices) {
 248                 dev = snd_device(list);
 249                 if (dev->type >= range_low && dev->type <= range_high) {
 250                         if ((err = snd_device_free(card, dev->device_data)) < 0)
 251                                 return err;
 252                         goto __again;
 253                 }
 254         }
 255         return 0;
 256 }