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/export.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  * Return: Zero if successful, or a negative error code on failure.
  43  */
  44 int snd_device_new(struct snd_card *card, enum snd_device_type type,
  45                    void *device_data, struct snd_device_ops *ops)
  46 {
  47         struct snd_device *dev;
  48         struct list_head *p;
  49
  50         if (snd_BUG_ON(!card || !device_data || !ops))
  51                 return -ENXIO;
  52         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  53         if (dev == NULL) {
  54                 dev_err(card->dev, "Cannot allocate device, type=%d\n", type);
  55                 return -ENOMEM;
  56         }
  57         INIT_LIST_HEAD(&dev->list);
  58         dev->card = card;
  59         dev->type = type;
  60         dev->state = SNDRV_DEV_BUILD;
  61         dev->device_data = device_data;
  62         dev->ops = ops;
  63
  64         /* insert the entry in an incrementally sorted list */
  65         list_for_each_prev(p, &card->devices) {
  66                 struct snd_device *pdev = list_entry(p, struct snd_device, list);
  67                 if ((unsigned int)pdev->type <= (unsigned int)type)
  68                         break;
  69         }
  70
  71         list_add(&dev->list, p);
  72         return 0;
  73 }
  74 EXPORT_SYMBOL(snd_device_new);
  75
  76 static int __snd_device_disconnect(struct snd_device *dev)
  77 {
  78         if (dev->state == SNDRV_DEV_REGISTERED) {
  79                 if (dev->ops->dev_disconnect &&
  80                     dev->ops->dev_disconnect(dev))
  81                         dev_err(dev->card->dev, "device disconnect failure\n");
  82                 dev->state = SNDRV_DEV_DISCONNECTED;
  83         }
  84         return 0;
  85 }
  86
  87 static void __snd_device_free(struct snd_device *dev)
  88 {
  89         /* unlink */
  90         list_del(&dev->list);
  91
  92         __snd_device_disconnect(dev);
  93         if (dev->ops->dev_free) {
  94                 if (dev->ops->dev_free(dev))
  95                         dev_err(dev->card->dev, "device free failure\n");
  96         }
  97         kfree(dev);
  98 }
  99
 100 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
 101 {
 102         struct snd_device *dev;
 103
 104         list_for_each_entry(dev, &card->devices, list)
 105                 if (dev->device_data == device_data)
 106                         return dev;
 107
 108         return NULL;
 109 }
 110
 111 /**
 112  * snd_device_free - release the device from the card
 113  * @card: the card instance
 114  * @device_data: the data pointer to release
 115  *
 116  * Removes the device from the list on the card and invokes the
 117  * callbacks, dev_disconnect and dev_free, corresponding to the state.
 118  * Then release the device.
 119  */
 120 void snd_device_free(struct snd_card *card, void *device_data)
 121 {
 122         struct snd_device *dev;
 123
 124         if (snd_BUG_ON(!card || !device_data))
 125                 return;
 126         dev = look_for_dev(card, device_data);
 127         if (dev)
 128                 __snd_device_free(dev);
 129         else
 130                 dev_dbg(card->dev, "device free %p (from %pF), not found\n",
 131                         device_data, __builtin_return_address(0));
 132 }
 133 EXPORT_SYMBOL(snd_device_free);
 134
 135 static int __snd_device_register(struct snd_device *dev)
 136 {
 137         if (dev->state == SNDRV_DEV_BUILD) {
 138                 if (dev->ops->dev_register) {
 139                         int err = dev->ops->dev_register(dev);
 140                         if (err < 0)
 141                                 return err;
 142                 }
 143                 dev->state = SNDRV_DEV_REGISTERED;
 144         }
 145         return 0;
 146 }
 147
 148 /**
 149  * snd_device_register - register the device
 150  * @card: the card instance
 151  * @device_data: the data pointer to register
 152  *
 153  * Registers the device which was already created via
 154  * snd_device_new().  Usually this is called from snd_card_register(),
 155  * but it can be called later if any new devices are created after
 156  * invocation of snd_card_register().
 157  *
 158  * Return: Zero if successful, or a negative error code on failure or if the
 159  * device not found.
 160  */
 161 int snd_device_register(struct snd_card *card, void *device_data)
 162 {
 163         struct snd_device *dev;
 164
 165         if (snd_BUG_ON(!card || !device_data))
 166                 return -ENXIO;
 167         dev = look_for_dev(card, device_data);
 168         if (dev)
 169                 return __snd_device_register(dev);
 170         snd_BUG();
 171         return -ENXIO;
 172 }
 173 EXPORT_SYMBOL(snd_device_register);
 174
 175 /*
 176  * register all the devices on the card.
 177  * called from init.c
 178  */
 179 int snd_device_register_all(struct snd_card *card)
 180 {
 181         struct snd_device *dev;
 182         int err;
 183
 184         if (snd_BUG_ON(!card))
 185                 return -ENXIO;
 186         list_for_each_entry(dev, &card->devices, list) {
 187                 err = __snd_device_register(dev);
 188                 if (err < 0)
 189                         return err;
 190         }
 191         return 0;
 192 }
 193
 194 /*
 195  * disconnect all the devices on the card.
 196  * called from init.c
 197  */
 198 int snd_device_disconnect_all(struct snd_card *card)
 199 {
 200         struct snd_device *dev;
 201         int err = 0;
 202
 203         if (snd_BUG_ON(!card))
 204                 return -ENXIO;
 205         list_for_each_entry_reverse(dev, &card->devices, list) {
 206                 if (__snd_device_disconnect(dev) < 0)
 207                         err = -ENXIO;
 208         }
 209         return err;
 210 }
 211
 212 /*
 213  * release all the devices on the card.
 214  * called from init.c
 215  */
 216 void snd_device_free_all(struct snd_card *card)
 217 {
 218         struct snd_device *dev, *next;
 219
 220         if (snd_BUG_ON(!card))
 221                 return;
 222         list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
 223                 __snd_device_free(dev);
 224 }