linux/sound/core/device.c
<<
>>
Prefs
   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 * Returns zero if successful, or a negative error code on failure.
  43 */
  44int 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        if (snd_BUG_ON(!card || !device_data || !ops))
  50                return -ENXIO;
  51        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  52        if (dev == NULL) {
  53                snd_printk(KERN_ERR "Cannot allocate device\n");
  54                return -ENOMEM;
  55        }
  56        dev->card = card;
  57        dev->type = type;
  58        dev->state = SNDRV_DEV_BUILD;
  59        dev->device_data = device_data;
  60        dev->ops = ops;
  61        list_add(&dev->list, &card->devices);   /* add to the head of list */
  62        return 0;
  63}
  64
  65EXPORT_SYMBOL(snd_device_new);
  66
  67/**
  68 * snd_device_free - release the device from the card
  69 * @card: the card instance
  70 * @device_data: the data pointer to release
  71 *
  72 * Removes the device from the list on the card and invokes the
  73 * callbacks, dev_disconnect and dev_free, corresponding to the state.
  74 * Then release the device.
  75 *
  76 * Returns zero if successful, or a negative error code on failure or if the
  77 * device not found.
  78 */
  79int snd_device_free(struct snd_card *card, void *device_data)
  80{
  81        struct snd_device *dev;
  82        
  83        if (snd_BUG_ON(!card || !device_data))
  84                return -ENXIO;
  85        list_for_each_entry(dev, &card->devices, list) {
  86                if (dev->device_data != device_data)
  87                        continue;
  88                /* unlink */
  89                list_del(&dev->list);
  90                if (dev->state == SNDRV_DEV_REGISTERED &&
  91                    dev->ops->dev_disconnect)
  92                        if (dev->ops->dev_disconnect(dev))
  93                                snd_printk(KERN_ERR
  94                                           "device disconnect failure\n");
  95                if (dev->ops->dev_free) {
  96                        if (dev->ops->dev_free(dev))
  97                                snd_printk(KERN_ERR "device free failure\n");
  98                }
  99                kfree(dev);
 100                return 0;
 101        }
 102        snd_printd("device free %p (from %pF), not found\n", device_data,
 103                   __builtin_return_address(0));
 104        return -ENXIO;
 105}
 106
 107EXPORT_SYMBOL(snd_device_free);
 108
 109/**
 110 * snd_device_disconnect - disconnect the device
 111 * @card: the card instance
 112 * @device_data: the data pointer to disconnect
 113 *
 114 * Turns the device into the disconnection state, invoking
 115 * dev_disconnect callback, if the device was already registered.
 116 *
 117 * Usually called from snd_card_disconnect().
 118 *
 119 * Returns zero if successful, or a negative error code on failure or if the
 120 * device not found.
 121 */
 122int snd_device_disconnect(struct snd_card *card, void *device_data)
 123{
 124        struct snd_device *dev;
 125
 126        if (snd_BUG_ON(!card || !device_data))
 127                return -ENXIO;
 128        list_for_each_entry(dev, &card->devices, list) {
 129                if (dev->device_data != device_data)
 130                        continue;
 131                if (dev->state == SNDRV_DEV_REGISTERED &&
 132                    dev->ops->dev_disconnect) {
 133                        if (dev->ops->dev_disconnect(dev))
 134                                snd_printk(KERN_ERR "device disconnect failure\n");
 135                        dev->state = SNDRV_DEV_DISCONNECTED;
 136                }
 137                return 0;
 138        }
 139        snd_printd("device disconnect %p (from %pF), not found\n", device_data,
 140                   __builtin_return_address(0));
 141        return -ENXIO;
 142}
 143
 144/**
 145 * snd_device_register - register the device
 146 * @card: the card instance
 147 * @device_data: the data pointer to register
 148 *
 149 * Registers the device which was already created via
 150 * snd_device_new().  Usually this is called from snd_card_register(),
 151 * but it can be called later if any new devices are created after
 152 * invocation of snd_card_register().
 153 *
 154 * Returns zero if successful, or a negative error code on failure or if the
 155 * device not found.
 156 */
 157int snd_device_register(struct snd_card *card, void *device_data)
 158{
 159        struct snd_device *dev;
 160        int err;
 161
 162        if (snd_BUG_ON(!card || !device_data))
 163                return -ENXIO;
 164        list_for_each_entry(dev, &card->devices, list) {
 165                if (dev->device_data != device_data)
 166                        continue;
 167                if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 168                        if ((err = dev->ops->dev_register(dev)) < 0)
 169                                return err;
 170                        dev->state = SNDRV_DEV_REGISTERED;
 171                        return 0;
 172                }
 173                snd_printd("snd_device_register busy\n");
 174                return -EBUSY;
 175        }
 176        snd_BUG();
 177        return -ENXIO;
 178}
 179
 180EXPORT_SYMBOL(snd_device_register);
 181
 182/*
 183 * register all the devices on the card.
 184 * called from init.c
 185 */
 186int snd_device_register_all(struct snd_card *card)
 187{
 188        struct snd_device *dev;
 189        int err;
 190        
 191        if (snd_BUG_ON(!card))
 192                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 */
 207int snd_device_disconnect_all(struct snd_card *card)
 208{
 209        struct snd_device *dev;
 210        int err = 0;
 211
 212        if (snd_BUG_ON(!card))
 213                return -ENXIO;
 214        list_for_each_entry(dev, &card->devices, list) {
 215                if (snd_device_disconnect(card, dev->device_data) < 0)
 216                        err = -ENXIO;
 217        }
 218        return err;
 219}
 220
 221/*
 222 * release all the devices on the card.
 223 * called from init.c
 224 */
 225int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
 226{
 227        struct snd_device *dev;
 228        int err;
 229        unsigned int range_low, range_high, type;
 230
 231        if (snd_BUG_ON(!card))
 232                return -ENXIO;
 233        range_low = (__force unsigned int)cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
 234        range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
 235      __again:
 236        list_for_each_entry(dev, &card->devices, list) {
 237                type = (__force unsigned int)dev->type;
 238                if (type >= range_low && type <= range_high) {
 239                        if ((err = snd_device_free(card, dev->device_data)) < 0)
 240                                return err;
 241                        goto __again;
 242                }
 243        }
 244        return 0;
 245}
 246
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.