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 /**
  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  * callback, dev_unregister or 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 list_head *list;
  81         struct snd_device *dev;
  82
  83         snd_assert(card != NULL, return -ENXIO);
  84         snd_assert(device_data != NULL, return -ENXIO);
  85         list_for_each(list, &card->devices) {
  86                 dev = snd_device(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->state == SNDRV_DEV_DISCONNECTED) &&
  93                     dev->ops->dev_unregister) {
  94                         if (dev->ops->dev_unregister(dev))
  95                                 snd_printk(KERN_ERR "device unregister failure\n");
  96                 } else {
  97                         if (dev->ops->dev_free) {
  98                                 if (dev->ops->dev_free(dev))
  99                                         snd_printk(KERN_ERR "device free failure\n");
 100                         }
 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 /**
 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 list_head *list;
 126         struct snd_device *dev;
 127
 128         snd_assert(card != NULL, return -ENXIO);
 129         snd_assert(device_data != NULL, return -ENXIO);
 130         list_for_each(list, &card->devices) {
 131                 dev = snd_device(list);
 132                 if (dev->device_data != device_data)
 133                         continue;
 134                 if (dev->state == SNDRV_DEV_REGISTERED &&
 135                     dev->ops->dev_disconnect) {
 136                         if (dev->ops->dev_disconnect(dev))
 137                                 snd_printk(KERN_ERR "device disconnect failure\n");
 138                         dev->state = SNDRV_DEV_DISCONNECTED;
 139                 }
 140                 return 0;
 141         }
 142         snd_printd("device disconnect %p (from %p), not found\n", device_data,
 143                    __builtin_return_address(0));
 144         return -ENXIO;
 145 }
 146
 147 /**
 148  * snd_device_register - register the device
 149  * @card: the card instance
 150  * @device_data: the data pointer to register
 151  *
 152  * Registers the device which was already created via
 153  * snd_device_new().  Usually this is called from snd_card_register(),
 154  * but it can be called later if any new devices are created after
 155  * invocation of snd_card_register().
 156  *
 157  * Returns zero if successful, or a negative error code on failure or if the
 158  * device not found.
 159  */
 160 int snd_device_register(struct snd_card *card, void *device_data)
 161 {
 162         struct list_head *list;
 163         struct snd_device *dev;
 164         int err;
 165
 166         snd_assert(card != NULL, return -ENXIO);
 167         snd_assert(device_data != NULL, return -ENXIO);
 168         list_for_each(list, &card->devices) {
 169                 dev = snd_device(list);
 170                 if (dev->device_data != device_data)
 171                         continue;
 172                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 173                         if ((err = dev->ops->dev_register(dev)) < 0)
 174                                 return err;
 175                         dev->state = SNDRV_DEV_REGISTERED;
 176                         return 0;
 177                 }
 178                 snd_printd("snd_device_register busy\n");
 179                 return -EBUSY;
 180         }
 181         snd_BUG();
 182         return -ENXIO;
 183 }
 184
 185 /*
 186  * register all the devices on the card.
 187  * called from init.c
 188  */
 189 int snd_device_register_all(struct snd_card *card)
 190 {
 191         struct list_head *list;
 192         struct snd_device *dev;
 193         int err;
 194
 195         snd_assert(card != NULL, return -ENXIO);
 196         list_for_each(list, &card->devices) {
 197                 dev = snd_device(list);
 198                 if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 199                         if ((err = dev->ops->dev_register(dev)) < 0)
 200                                 return err;
 201                         dev->state = SNDRV_DEV_REGISTERED;
 202                 }
 203         }
 204         return 0;
 205 }
 206
 207 /*
 208  * disconnect all the devices on the card.
 209  * called from init.c
 210  */
 211 int snd_device_disconnect_all(struct snd_card *card)
 212 {
 213         struct snd_device *dev;
 214         struct list_head *list;
 215         int err = 0;
 216
 217         snd_assert(card != NULL, return -ENXIO);
 218         list_for_each(list, &card->devices) {
 219                 dev = snd_device(list);
 220                 if (snd_device_disconnect(card, dev->device_data) < 0)
 221                         err = -ENXIO;
 222         }
 223         return err;
 224 }
 225
 226 /*
 227  * release all the devices on the card.
 228  * called from init.c
 229  */
 230 int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 231 {
 232         struct snd_device *dev;
 233         struct list_head *list;
 234         int err;
 235         unsigned int range_low, range_high;
 236
 237         snd_assert(card != NULL, return -ENXIO);
 238         range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 239         range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 240       __again:
 241         list_for_each(list, &card->devices) {
 242                 dev = snd_device(list);
 243                 if (dev->type >= range_low && dev->type <= range_high) {
 244                         if ((err = snd_device_free(card, dev->device_data)) < 0)
 245                                 return err;
 246                         goto __again;
 247                 }
 248         }
 249         return 0;
 250 }