sound/core/init.c

   1 /*
   2  *  Initialization 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/init.h>
  24 #include <linux/sched.h>
  25 #include <linux/file.h>
  26 #include <linux/slab.h>
  27 #include <linux/time.h>
  28 #include <linux/ctype.h>
  29 #include <linux/pci.h>
  30 #include <linux/pm.h>
  31
  32 #include <sound/core.h>
  33 #include <sound/control.h>
  34 #include <sound/info.h>
  35
  36 static DEFINE_SPINLOCK(shutdown_lock);
  37 static LIST_HEAD(shutdown_files);
  38
  39 static const struct file_operations snd_shutdown_f_ops;
  40
  41 static unsigned int snd_cards_lock;     /* locked for registering/using */
  42 struct snd_card *snd_cards[SNDRV_CARDS];
  43 EXPORT_SYMBOL(snd_cards);
  44
  45 static DEFINE_MUTEX(snd_card_mutex);
  46
  47 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
  48 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
  49 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
  50 #endif
  51
  52 #ifdef CONFIG_PROC_FS
  53 static void snd_card_id_read(struct snd_info_entry *entry,
  54                              struct snd_info_buffer *buffer)
  55 {
  56         snd_iprintf(buffer, "%s\n", entry->card->id);
  57 }
  58
  59 static inline int init_info_for_card(struct snd_card *card)
  60 {
  61         int err;
  62         struct snd_info_entry *entry;
  63
  64         if ((err = snd_info_card_register(card)) < 0) {
  65                 snd_printd("unable to create card info\n");
  66                 return err;
  67         }
  68         if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
  69                 snd_printd("unable to create card entry\n");
  70                 return err;
  71         }
  72         entry->c.text.read = snd_card_id_read;
  73         if (snd_info_register(entry) < 0) {
  74                 snd_info_free_entry(entry);
  75                 entry = NULL;
  76         }
  77         card->proc_id = entry;
  78         return 0;
  79 }
  80 #else /* !CONFIG_PROC_FS */
  81 #define init_info_for_card(card)
  82 #endif
  83
  84 /**
  85  *  snd_card_new - create and initialize a soundcard structure
  86  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
  87  *  @xid: card identification (ASCII string)
  88  *  @module: top level module for locking
  89  *  @extra_size: allocate this extra size after the main soundcard structure
  90  *
  91  *  Creates and initializes a soundcard structure.
  92  *
  93  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
  94  *  (which is blocked until snd_card_register function is called).
  95  */
  96 struct snd_card *snd_card_new(int idx, const char *xid,
  97                          struct module *module, int extra_size)
  98 {
  99         struct snd_card *card;
 100         int err;
 101
 102         if (extra_size < 0)
 103                 extra_size = 0;
 104         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 105         if (card == NULL)
 106                 return NULL;
 107         if (xid) {
 108                 if (!snd_info_check_reserved_words(xid))
 109                         goto __error;
 110                 strlcpy(card->id, xid, sizeof(card->id));
 111         }
 112         err = 0;
 113         mutex_lock(&snd_card_mutex);
 114         if (idx < 0) {
 115                 int idx2;
 116                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
 117                         /* idx == -1 == 0xffff means: take any free slot */
 118                         if (~snd_cards_lock & idx & 1<<idx2) {
 119                                 idx = idx2;
 120                                 if (idx >= snd_ecards_limit)
 121                                         snd_ecards_limit = idx + 1;
 122                                 break;
 123                         }
 124         } else {
 125                  if (idx < snd_ecards_limit) {
 126                         if (snd_cards_lock & (1 << idx))
 127                                 err = -EBUSY;   /* invalid */
 128                 } else {
 129                         if (idx < SNDRV_CARDS)
 130                                 snd_ecards_limit = idx + 1; /* increase the limit */
 131                         else
 132                                 err = -ENODEV;
 133                 }
 134         }
 135         if (idx < 0 || err < 0) {
 136                 mutex_unlock(&snd_card_mutex);
 137                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
 138                          idx, snd_ecards_limit - 1, err);
 139                 goto __error;
 140         }
 141         snd_cards_lock |= 1 << idx;             /* lock it */
 142         mutex_unlock(&snd_card_mutex);
 143         card->number = idx;
 144         card->module = module;
 145         INIT_LIST_HEAD(&card->devices);
 146         init_rwsem(&card->controls_rwsem);
 147         rwlock_init(&card->ctl_files_rwlock);
 148         INIT_LIST_HEAD(&card->controls);
 149         INIT_LIST_HEAD(&card->ctl_files);
 150         spin_lock_init(&card->files_lock);
 151         init_waitqueue_head(&card->shutdown_sleep);
 152 #ifdef CONFIG_PM
 153         mutex_init(&card->power_lock);
 154         init_waitqueue_head(&card->power_sleep);
 155 #endif
 156         /* the control interface cannot be accessed from the user space until */
 157         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 158         if ((err = snd_ctl_create(card)) < 0) {
 159                 snd_printd("unable to register control minors\n");
 160                 goto __error;
 161         }
 162         if ((err = snd_info_card_create(card)) < 0) {
 163                 snd_printd("unable to create card info\n");
 164                 goto __error_ctl;
 165         }
 166         if (extra_size > 0)
 167                 card->private_data = (char *)card + sizeof(struct snd_card);
 168         return card;
 169
 170       __error_ctl:
 171         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
 172       __error:
 173         kfree(card);
 174         return NULL;
 175 }
 176
 177 EXPORT_SYMBOL(snd_card_new);
 178
 179 /* return non-zero if a card is already locked */
 180 int snd_card_locked(int card)
 181 {
 182         int locked;
 183
 184         mutex_lock(&snd_card_mutex);
 185         locked = snd_cards_lock & (1 << card);
 186         mutex_unlock(&snd_card_mutex);
 187         return locked;
 188 }
 189
 190 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
 191 {
 192         return -ENODEV;
 193 }
 194
 195 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
 196                                    size_t count, loff_t *offset)
 197 {
 198         return -ENODEV;
 199 }
 200
 201 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
 202                                     size_t count, loff_t *offset)
 203 {
 204         return -ENODEV;
 205 }
 206
 207 static int snd_disconnect_release(struct inode *inode, struct file *file)
 208 {
 209         struct snd_monitor_file *df = NULL, *_df;
 210
 211         spin_lock(&shutdown_lock);
 212         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
 213                 if (_df->file == file) {
 214                         df = _df;
 215                         break;
 216                 }
 217         }
 218         spin_unlock(&shutdown_lock);
 219
 220         if (likely(df))
 221                 return df->disconnected_f_op->release(inode, file);
 222
 223         panic("%s(%p, %p) failed!", __FUNCTION__, inode, file);
 224 }
 225
 226 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
 227 {
 228         return POLLERR | POLLNVAL;
 229 }
 230
 231 static long snd_disconnect_ioctl(struct file *file,
 232                                  unsigned int cmd, unsigned long arg)
 233 {
 234         return -ENODEV;
 235 }
 236
 237 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
 238 {
 239         return -ENODEV;
 240 }
 241
 242 static int snd_disconnect_fasync(int fd, struct file *file, int on)
 243 {
 244         return -ENODEV;
 245 }
 246
 247 static const struct file_operations snd_shutdown_f_ops =
 248 {
 249         .owner =        THIS_MODULE,
 250         .llseek =       snd_disconnect_llseek,
 251         .read =         snd_disconnect_read,
 252         .write =        snd_disconnect_write,
 253         .release =      snd_disconnect_release,
 254         .poll =         snd_disconnect_poll,
 255         .unlocked_ioctl = snd_disconnect_ioctl,
 256 #ifdef CONFIG_COMPAT
 257         .compat_ioctl = snd_disconnect_ioctl,
 258 #endif
 259         .mmap =         snd_disconnect_mmap,
 260         .fasync =       snd_disconnect_fasync
 261 };
 262
 263 /**
 264  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 265  *  @card: soundcard structure
 266  *
 267  *  Disconnects all APIs from the file-operations (user space).
 268  *
 269  *  Returns zero, otherwise a negative error code.
 270  *
 271  *  Note: The current implementation replaces all active file->f_op with special
 272  *        dummy file operations (they do nothing except release).
 273  */
 274 int snd_card_disconnect(struct snd_card *card)
 275 {
 276         struct snd_monitor_file *mfile;
 277         struct file *file;
 278         int err;
 279
 280         spin_lock(&card->files_lock);
 281         if (card->shutdown) {
 282                 spin_unlock(&card->files_lock);
 283                 return 0;
 284         }
 285         card->shutdown = 1;
 286         spin_unlock(&card->files_lock);
 287
 288         /* phase 1: disable fops (user space) operations for ALSA API */
 289         mutex_lock(&snd_card_mutex);
 290         snd_cards[card->number] = NULL;
 291         mutex_unlock(&snd_card_mutex);
 292
 293         /* phase 2: replace file->f_op with special dummy operations */
 294
 295         spin_lock(&card->files_lock);
 296         mfile = card->files;
 297         while (mfile) {
 298                 file = mfile->file;
 299
 300                 /* it's critical part, use endless loop */
 301                 /* we have no room to fail */
 302                 mfile->disconnected_f_op = mfile->file->f_op;
 303
 304                 spin_lock(&shutdown_lock);
 305                 list_add(&mfile->shutdown_list, &shutdown_files);
 306                 spin_unlock(&shutdown_lock);
 307
 308                 fops_get(&snd_shutdown_f_ops);
 309                 mfile->file->f_op = &snd_shutdown_f_ops;
 310
 311                 mfile = mfile->next;
 312         }
 313         spin_unlock(&card->files_lock);
 314
 315         /* phase 3: notify all connected devices about disconnection */
 316         /* at this point, they cannot respond to any calls except release() */
 317
 318 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 319         if (snd_mixer_oss_notify_callback)
 320                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 321 #endif
 322
 323         /* notify all devices that we are disconnected */
 324         err = snd_device_disconnect_all(card);
 325         if (err < 0)
 326                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 327
 328         snd_info_card_disconnect(card);
 329         return 0;
 330 }
 331
 332 EXPORT_SYMBOL(snd_card_disconnect);
 333
 334 /**
 335  *  snd_card_free - frees given soundcard structure
 336  *  @card: soundcard structure
 337  *
 338  *  This function releases the soundcard structure and the all assigned
 339  *  devices automatically.  That is, you don't have to release the devices
 340  *  by yourself.
 341  *
 342  *  Returns zero. Frees all associated devices and frees the control
 343  *  interface associated to given soundcard.
 344  */
 345 static int snd_card_do_free(struct snd_card *card)
 346 {
 347 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 348         if (snd_mixer_oss_notify_callback)
 349                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 350 #endif
 351         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
 352                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
 353                 /* Fatal, but this situation should never occur */
 354         }
 355         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
 356                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
 357                 /* Fatal, but this situation should never occur */
 358         }
 359         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
 360                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
 361                 /* Fatal, but this situation should never occur */
 362         }
 363         if (card->private_free)
 364                 card->private_free(card);
 365         snd_info_free_entry(card->proc_id);
 366         if (snd_info_card_free(card) < 0) {
 367                 snd_printk(KERN_WARNING "unable to free card info\n");
 368                 /* Not fatal error */
 369         }
 370 #ifndef CONFIG_SYSFS_DEPRECATED
 371         if (card->card_dev)
 372                 device_unregister(card->card_dev);
 373 #endif
 374         kfree(card);
 375         return 0;
 376 }
 377
 378 static int snd_card_free_prepare(struct snd_card *card)
 379 {
 380         if (card == NULL)
 381                 return -EINVAL;
 382         (void) snd_card_disconnect(card);
 383         mutex_lock(&snd_card_mutex);
 384         snd_cards[card->number] = NULL;
 385         snd_cards_lock &= ~(1 << card->number);
 386         mutex_unlock(&snd_card_mutex);
 387 #ifdef CONFIG_PM
 388         wake_up(&card->power_sleep);
 389 #endif
 390         return 0;
 391 }
 392
 393 int snd_card_free_when_closed(struct snd_card *card)
 394 {
 395         int free_now = 0;
 396         int ret = snd_card_free_prepare(card);
 397         if (ret)
 398                 return ret;
 399
 400         spin_lock(&card->files_lock);
 401         if (card->files == NULL)
 402                 free_now = 1;
 403         else
 404                 card->free_on_last_close = 1;
 405         spin_unlock(&card->files_lock);
 406
 407         if (free_now)
 408                 snd_card_do_free(card);
 409         return 0;
 410 }
 411
 412 EXPORT_SYMBOL(snd_card_free_when_closed);
 413
 414 int snd_card_free(struct snd_card *card)
 415 {
 416         int ret = snd_card_free_prepare(card);
 417         if (ret)
 418                 return ret;
 419
 420         /* wait, until all devices are ready for the free operation */
 421         wait_event(card->shutdown_sleep, card->files == NULL);
 422         snd_card_do_free(card);
 423         return 0;
 424 }
 425
 426 EXPORT_SYMBOL(snd_card_free);
 427
 428 static void choose_default_id(struct snd_card *card)
 429 {
 430         int i, len, idx_flag = 0, loops = SNDRV_CARDS;
 431         char *id, *spos;
 432
 433         id = spos = card->shortname;
 434         while (*id != '\0') {
 435                 if (*id == ' ')
 436                         spos = id + 1;
 437                 id++;
 438         }
 439         id = card->id;
 440         while (*spos != '\0' && !isalnum(*spos))
 441                 spos++;
 442         if (isdigit(*spos))
 443                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
 444         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 445                 if (isalnum(*spos))
 446                         *id++ = *spos;
 447                 spos++;
 448         }
 449         *id = '\0';
 450
 451         id = card->id;
 452
 453         if (*id == '\0')
 454                 strcpy(id, "default");
 455
 456         while (1) {
 457                 if (loops-- == 0) {
 458                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
 459                         strcpy(card->id, card->proc_root->name);
 460                         return;
 461                 }
 462                 if (!snd_info_check_reserved_words(id))
 463                         goto __change;
 464                 for (i = 0; i < snd_ecards_limit; i++) {
 465                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
 466                                 goto __change;
 467                 }
 468                 break;
 469
 470               __change:
 471                 len = strlen(id);
 472                 if (idx_flag) {
 473                         if (id[len-1] != '9')
 474                                 id[len-1]++;
 475                         else
 476                                 id[len-1] = 'A';
 477                 } else if ((size_t)len <= sizeof(card->id) - 3) {
 478                         strcat(id, "_1");
 479                         idx_flag++;
 480                 } else {
 481                         spos = id + len - 2;
 482                         if ((size_t)len <= sizeof(card->id) - 2)
 483                                 spos++;
 484                         *spos++ = '_';
 485                         *spos++ = '1';
 486                         *spos++ = '\0';
 487                         idx_flag++;
 488                 }
 489         }
 490 }
 491
 492 /**
 493  *  snd_card_register - register the soundcard
 494  *  @card: soundcard structure
 495  *
 496  *  This function registers all the devices assigned to the soundcard.
 497  *  Until calling this, the ALSA control interface is blocked from the
 498  *  external accesses.  Thus, you should call this function at the end
 499  *  of the initialization of the card.
 500  *
 501  *  Returns zero otherwise a negative error code if the registrain failed.
 502  */
 503 int snd_card_register(struct snd_card *card)
 504 {
 505         int err;
 506
 507         snd_assert(card != NULL, return -EINVAL);
 508 #ifndef CONFIG_SYSFS_DEPRECATED
 509         if (!card->card_dev) {
 510                 card->card_dev = device_create(sound_class, card->dev, 0,
 511                                                "card%i", card->number);
 512                 if (IS_ERR(card->card_dev))
 513                         card->card_dev = NULL;
 514         }
 515 #endif
 516         if ((err = snd_device_register_all(card)) < 0)
 517                 return err;
 518         mutex_lock(&snd_card_mutex);
 519         if (snd_cards[card->number]) {
 520                 /* already registered */
 521                 mutex_unlock(&snd_card_mutex);
 522                 return 0;
 523         }
 524         if (card->id[0] == '\0')
 525                 choose_default_id(card);
 526         snd_cards[card->number] = card;
 527         mutex_unlock(&snd_card_mutex);
 528         init_info_for_card(card);
 529 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 530         if (snd_mixer_oss_notify_callback)
 531                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 532 #endif
 533         return 0;
 534 }
 535
 536 EXPORT_SYMBOL(snd_card_register);
 537
 538 #ifdef CONFIG_PROC_FS
 539 static struct snd_info_entry *snd_card_info_entry;
 540
 541 static void snd_card_info_read(struct snd_info_entry *entry,
 542                                struct snd_info_buffer *buffer)
 543 {
 544         int idx, count;
 545         struct snd_card *card;
 546
 547         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 548                 mutex_lock(&snd_card_mutex);
 549                 if ((card = snd_cards[idx]) != NULL) {
 550                         count++;
 551                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 552                                         idx,
 553                                         card->id,
 554                                         card->driver,
 555                                         card->shortname);
 556                         snd_iprintf(buffer, "                      %s\n",
 557                                         card->longname);
 558                 }
 559                 mutex_unlock(&snd_card_mutex);
 560         }
 561         if (!count)
 562                 snd_iprintf(buffer, "--- no soundcards ---\n");
 563 }
 564
 565 #ifdef CONFIG_SND_OSSEMUL
 566
 567 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 568 {
 569         int idx, count;
 570         struct snd_card *card;
 571
 572         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 573                 mutex_lock(&snd_card_mutex);
 574                 if ((card = snd_cards[idx]) != NULL) {
 575                         count++;
 576                         snd_iprintf(buffer, "%s\n", card->longname);
 577                 }
 578                 mutex_unlock(&snd_card_mutex);
 579         }
 580         if (!count) {
 581                 snd_iprintf(buffer, "--- no soundcards ---\n");
 582         }
 583 }
 584
 585 #endif
 586
 587 #ifdef MODULE
 588 static struct snd_info_entry *snd_card_module_info_entry;
 589 static void snd_card_module_info_read(struct snd_info_entry *entry,
 590                                       struct snd_info_buffer *buffer)
 591 {
 592         int idx;
 593         struct snd_card *card;
 594
 595         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 596                 mutex_lock(&snd_card_mutex);
 597                 if ((card = snd_cards[idx]) != NULL)
 598                         snd_iprintf(buffer, "%2i %s\n",
 599                                     idx, card->module->name);
 600                 mutex_unlock(&snd_card_mutex);
 601         }
 602 }
 603 #endif
 604
 605 int __init snd_card_info_init(void)
 606 {
 607         struct snd_info_entry *entry;
 608
 609         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 610         if (! entry)
 611                 return -ENOMEM;
 612         entry->c.text.read = snd_card_info_read;
 613         if (snd_info_register(entry) < 0) {
 614                 snd_info_free_entry(entry);
 615                 return -ENOMEM;
 616         }
 617         snd_card_info_entry = entry;
 618
 619 #ifdef MODULE
 620         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 621         if (entry) {
 622                 entry->c.text.read = snd_card_module_info_read;
 623                 if (snd_info_register(entry) < 0)
 624                         snd_info_free_entry(entry);
 625                 else
 626                         snd_card_module_info_entry = entry;
 627         }
 628 #endif
 629
 630         return 0;
 631 }
 632
 633 int __exit snd_card_info_done(void)
 634 {
 635         snd_info_free_entry(snd_card_info_entry);
 636 #ifdef MODULE
 637         snd_info_free_entry(snd_card_module_info_entry);
 638 #endif
 639         return 0;
 640 }
 641
 642 #endif /* CONFIG_PROC_FS */
 643
 644 /**
 645  *  snd_component_add - add a component string
 646  *  @card: soundcard structure
 647  *  @component: the component id string
 648  *
 649  *  This function adds the component id string to the supported list.
 650  *  The component can be referred from the alsa-lib.
 651  *
 652  *  Returns zero otherwise a negative error code.
 653  */
 654
 655 int snd_component_add(struct snd_card *card, const char *component)
 656 {
 657         char *ptr;
 658         int len = strlen(component);
 659
 660         ptr = strstr(card->components, component);
 661         if (ptr != NULL) {
 662                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 663                         return 1;
 664         }
 665         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 666                 snd_BUG();
 667                 return -ENOMEM;
 668         }
 669         if (card->components[0] != '\0')
 670                 strcat(card->components, " ");
 671         strcat(card->components, component);
 672         return 0;
 673 }
 674
 675 EXPORT_SYMBOL(snd_component_add);
 676
 677 /**
 678  *  snd_card_file_add - add the file to the file list of the card
 679  *  @card: soundcard structure
 680  *  @file: file pointer
 681  *
 682  *  This function adds the file to the file linked-list of the card.
 683  *  This linked-list is used to keep tracking the connection state,
 684  *  and to avoid the release of busy resources by hotplug.
 685  *
 686  *  Returns zero or a negative error code.
 687  */
 688 int snd_card_file_add(struct snd_card *card, struct file *file)
 689 {
 690         struct snd_monitor_file *mfile;
 691
 692         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 693         if (mfile == NULL)
 694                 return -ENOMEM;
 695         mfile->file = file;
 696         mfile->disconnected_f_op = NULL;
 697         mfile->next = NULL;
 698         spin_lock(&card->files_lock);
 699         if (card->shutdown) {
 700                 spin_unlock(&card->files_lock);
 701                 kfree(mfile);
 702                 return -ENODEV;
 703         }
 704         mfile->next = card->files;
 705         card->files = mfile;
 706         spin_unlock(&card->files_lock);
 707         return 0;
 708 }
 709
 710 EXPORT_SYMBOL(snd_card_file_add);
 711
 712 /**
 713  *  snd_card_file_remove - remove the file from the file list
 714  *  @card: soundcard structure
 715  *  @file: file pointer
 716  *
 717  *  This function removes the file formerly added to the card via
 718  *  snd_card_file_add() function.
 719  *  If all files are removed and snd_card_free_when_closed() was
 720  *  called beforehand, it processes the pending release of
 721  *  resources.
 722  *
 723  *  Returns zero or a negative error code.
 724  */
 725 int snd_card_file_remove(struct snd_card *card, struct file *file)
 726 {
 727         struct snd_monitor_file *mfile, *pfile = NULL;
 728         int last_close = 0;
 729
 730         spin_lock(&card->files_lock);
 731         mfile = card->files;
 732         while (mfile) {
 733                 if (mfile->file == file) {
 734                         if (pfile)
 735                                 pfile->next = mfile->next;
 736                         else
 737                                 card->files = mfile->next;
 738                         break;
 739                 }
 740                 pfile = mfile;
 741                 mfile = mfile->next;
 742         }
 743         if (mfile && mfile->disconnected_f_op) {
 744                 fops_put(mfile->disconnected_f_op);
 745                 spin_lock(&shutdown_lock);
 746                 list_del(&mfile->shutdown_list);
 747                 spin_unlock(&shutdown_lock);
 748         }
 749         if (card->files == NULL)
 750                 last_close = 1;
 751         spin_unlock(&card->files_lock);
 752         if (last_close) {
 753                 wake_up(&card->shutdown_sleep);
 754                 if (card->free_on_last_close)
 755                         snd_card_do_free(card);
 756         }
 757         if (!mfile) {
 758                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 759                 return -ENOENT;
 760         }
 761         kfree(mfile);
 762         return 0;
 763 }
 764
 765 EXPORT_SYMBOL(snd_card_file_remove);
 766
 767 #ifdef CONFIG_PM
 768 /**
 769  *  snd_power_wait - wait until the power-state is changed.
 770  *  @card: soundcard structure
 771  *  @power_state: expected power state
 772  *
 773  *  Waits until the power-state is changed.
 774  *
 775  *  Note: the power lock must be active before call.
 776  */
 777 int snd_power_wait(struct snd_card *card, unsigned int power_state)
 778 {
 779         wait_queue_t wait;
 780         int result = 0;
 781
 782         /* fastpath */
 783         if (snd_power_get_state(card) == power_state)
 784                 return 0;
 785         init_waitqueue_entry(&wait, current);
 786         add_wait_queue(&card->power_sleep, &wait);
 787         while (1) {
 788                 if (card->shutdown) {
 789                         result = -ENODEV;
 790                         break;
 791                 }
 792                 if (snd_power_get_state(card) == power_state)
 793                         break;
 794                 set_current_state(TASK_UNINTERRUPTIBLE);
 795                 snd_power_unlock(card);
 796                 schedule_timeout(30 * HZ);
 797                 snd_power_lock(card);
 798         }
 799         remove_wait_queue(&card->power_sleep, &wait);
 800         return result;
 801 }
 802
 803 EXPORT_SYMBOL(snd_power_wait);
 804 #endif /* CONFIG_PM */