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