sound/core/init.c

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