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 <linux/init.h>
  23 #include <linux/sched.h>
  24 #include <linux/file.h>
  25 #include <linux/slab.h>
  26 #include <linux/time.h>
  27 #include <linux/ctype.h>
  28 #include <linux/pm.h>
  29
  30 #include <sound/core.h>
  31 #include <sound/control.h>
  32 #include <sound/info.h>
  33
  34 static DEFINE_SPINLOCK(shutdown_lock);
  35 static LIST_HEAD(shutdown_files);
  36
  37 static const struct file_operations snd_shutdown_f_ops;
  38
  39 static unsigned int snd_cards_lock;     /* locked for registering/using */
  40 struct snd_card *snd_cards[SNDRV_CARDS];
  41 EXPORT_SYMBOL(snd_cards);
  42
  43 static DEFINE_MUTEX(snd_card_mutex);
  44
  45 static char *slots[SNDRV_CARDS];
  46 module_param_array(slots, charp, NULL, 0444);
  47 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
  48
  49 /* return non-zero if the given index is already reserved for another
  50  * module via slots option
  51  */
  52 static int module_slot_mismatch(struct module *module, int idx)
  53 {
  54 #ifdef MODULE
  55         char *s1, *s2;
  56         if (!module || !module->name || !slots[idx])
  57                 return 0;
  58         s1 = slots[idx];
  59         s2 = module->name;
  60         /* compare module name strings
  61          * hyphens are handled as equivalent with underscore
  62          */
  63         for (;;) {
  64                 char c1 = *s1++;
  65                 char c2 = *s2++;
  66                 if (c1 == '-')
  67                         c1 = '_';
  68                 if (c2 == '-')
  69                         c2 = '_';
  70                 if (c1 != c2)
  71                         return 1;
  72                 if (!c1)
  73                         break;
  74         }
  75 #endif
  76         return 0;
  77 }
  78
  79 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
  80 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
  81 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
  82 #endif
  83
  84 #ifdef CONFIG_PROC_FS
  85 static void snd_card_id_read(struct snd_info_entry *entry,
  86                              struct snd_info_buffer *buffer)
  87 {
  88         snd_iprintf(buffer, "%s\n", entry->card->id);
  89 }
  90
  91 static inline int init_info_for_card(struct snd_card *card)
  92 {
  93         int err;
  94         struct snd_info_entry *entry;
  95
  96         if ((err = snd_info_card_register(card)) < 0) {
  97                 snd_printd("unable to create card info\n");
  98                 return err;
  99         }
 100         if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
 101                 snd_printd("unable to create card entry\n");
 102                 return err;
 103         }
 104         entry->c.text.read = snd_card_id_read;
 105         if (snd_info_register(entry) < 0) {
 106                 snd_info_free_entry(entry);
 107                 entry = NULL;
 108         }
 109         card->proc_id = entry;
 110         return 0;
 111 }
 112 #else /* !CONFIG_PROC_FS */
 113 #define init_info_for_card(card)
 114 #endif
 115
 116 /**
 117  *  snd_card_new - create and initialize a soundcard structure
 118  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 119  *  @xid: card identification (ASCII string)
 120  *  @module: top level module for locking
 121  *  @extra_size: allocate this extra size after the main soundcard structure
 122  *
 123  *  Creates and initializes a soundcard structure.
 124  *
 125  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
 126  *  (which is blocked until snd_card_register function is called).
 127  */
 128 struct snd_card *snd_card_new(int idx, const char *xid,
 129                          struct module *module, int extra_size)
 130 {
 131         struct snd_card *card;
 132         int err;
 133
 134         if (extra_size < 0)
 135                 extra_size = 0;
 136         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 137         if (card == NULL)
 138                 return NULL;
 139         if (xid) {
 140                 if (!snd_info_check_reserved_words(xid))
 141                         goto __error;
 142                 strlcpy(card->id, xid, sizeof(card->id));
 143         }
 144         err = 0;
 145         mutex_lock(&snd_card_mutex);
 146         if (idx < 0) {
 147                 int idx2;
 148                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
 149                         /* idx == -1 == 0xffff means: take any free slot */
 150                         if (~snd_cards_lock & idx & 1<<idx2) {
 151                                 if (module_slot_mismatch(module, idx2))
 152                                         continue;
 153                                 idx = idx2;
 154                                 if (idx >= snd_ecards_limit)
 155                                         snd_ecards_limit = idx + 1;
 156                                 break;
 157                         }
 158         } else {
 159                  if (idx < snd_ecards_limit) {
 160                         if (snd_cards_lock & (1 << idx))
 161                                 err = -EBUSY;   /* invalid */
 162                 } else {
 163                         if (idx < SNDRV_CARDS)
 164                                 snd_ecards_limit = idx + 1; /* increase the limit */
 165                         else
 166                                 err = -ENODEV;
 167                 }
 168         }
 169         if (idx < 0 || err < 0) {
 170                 mutex_unlock(&snd_card_mutex);
 171                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
 172                          idx, snd_ecards_limit - 1, err);
 173                 goto __error;
 174         }
 175         snd_cards_lock |= 1 << idx;             /* lock it */
 176         mutex_unlock(&snd_card_mutex);
 177         card->number = idx;
 178         card->module = module;
 179         INIT_LIST_HEAD(&card->devices);
 180         init_rwsem(&card->controls_rwsem);
 181         rwlock_init(&card->ctl_files_rwlock);
 182         INIT_LIST_HEAD(&card->controls);
 183         INIT_LIST_HEAD(&card->ctl_files);
 184         spin_lock_init(&card->files_lock);
 185         init_waitqueue_head(&card->shutdown_sleep);
 186 #ifdef CONFIG_PM
 187         mutex_init(&card->power_lock);
 188         init_waitqueue_head(&card->power_sleep);
 189 #endif
 190         /* the control interface cannot be accessed from the user space until */
 191         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 192         if ((err = snd_ctl_create(card)) < 0) {
 193                 snd_printd("unable to register control minors\n");
 194                 goto __error;
 195         }
 196         if ((err = snd_info_card_create(card)) < 0) {
 197                 snd_printd("unable to create card info\n");
 198                 goto __error_ctl;
 199         }
 200         if (extra_size > 0)
 201                 card->private_data = (char *)card + sizeof(struct snd_card);
 202         return card;
 203
 204       __error_ctl:
 205         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
 206       __error:
 207         kfree(card);
 208         return NULL;
 209 }
 210
 211 EXPORT_SYMBOL(snd_card_new);
 212
 213 /* return non-zero if a card is already locked */
 214 int snd_card_locked(int card)
 215 {
 216         int locked;
 217
 218         mutex_lock(&snd_card_mutex);
 219         locked = snd_cards_lock & (1 << card);
 220         mutex_unlock(&snd_card_mutex);
 221         return locked;
 222 }
 223
 224 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
 225 {
 226         return -ENODEV;
 227 }
 228
 229 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
 230                                    size_t count, loff_t *offset)
 231 {
 232         return -ENODEV;
 233 }
 234
 235 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
 236                                     size_t count, loff_t *offset)
 237 {
 238         return -ENODEV;
 239 }
 240
 241 static int snd_disconnect_release(struct inode *inode, struct file *file)
 242 {
 243         struct snd_monitor_file *df = NULL, *_df;
 244
 245         spin_lock(&shutdown_lock);
 246         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
 247                 if (_df->file == file) {
 248                         df = _df;
 249                         break;
 250                 }
 251         }
 252         spin_unlock(&shutdown_lock);
 253
 254         if (likely(df))
 255                 return df->disconnected_f_op->release(inode, file);
 256
 257         panic("%s(%p, %p) failed!", __func__, inode, file);
 258 }
 259
 260 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
 261 {
 262         return POLLERR | POLLNVAL;
 263 }
 264
 265 static long snd_disconnect_ioctl(struct file *file,
 266                                  unsigned int cmd, unsigned long arg)
 267 {
 268         return -ENODEV;
 269 }
 270
 271 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
 272 {
 273         return -ENODEV;
 274 }
 275
 276 static int snd_disconnect_fasync(int fd, struct file *file, int on)
 277 {
 278         return -ENODEV;
 279 }
 280
 281 static const struct file_operations snd_shutdown_f_ops =
 282 {
 283         .owner =        THIS_MODULE,
 284         .llseek =       snd_disconnect_llseek,
 285         .read =         snd_disconnect_read,
 286         .write =        snd_disconnect_write,
 287         .release =      snd_disconnect_release,
 288         .poll =         snd_disconnect_poll,
 289         .unlocked_ioctl = snd_disconnect_ioctl,
 290 #ifdef CONFIG_COMPAT
 291         .compat_ioctl = snd_disconnect_ioctl,
 292 #endif
 293         .mmap =         snd_disconnect_mmap,
 294         .fasync =       snd_disconnect_fasync
 295 };
 296
 297 /**
 298  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 299  *  @card: soundcard structure
 300  *
 301  *  Disconnects all APIs from the file-operations (user space).
 302  *
 303  *  Returns zero, otherwise a negative error code.
 304  *
 305  *  Note: The current implementation replaces all active file->f_op with special
 306  *        dummy file operations (they do nothing except release).
 307  */
 308 int snd_card_disconnect(struct snd_card *card)
 309 {
 310         struct snd_monitor_file *mfile;
 311         struct file *file;
 312         int err;
 313
 314         if (!card)
 315                 return -EINVAL;
 316
 317         spin_lock(&card->files_lock);
 318         if (card->shutdown) {
 319                 spin_unlock(&card->files_lock);
 320                 return 0;
 321         }
 322         card->shutdown = 1;
 323         spin_unlock(&card->files_lock);
 324
 325         /* phase 1: disable fops (user space) operations for ALSA API */
 326         mutex_lock(&snd_card_mutex);
 327         snd_cards[card->number] = NULL;
 328         snd_cards_lock &= ~(1 << card->number);
 329         mutex_unlock(&snd_card_mutex);
 330
 331         /* phase 2: replace file->f_op with special dummy operations */
 332
 333         spin_lock(&card->files_lock);
 334         mfile = card->files;
 335         while (mfile) {
 336                 file = mfile->file;
 337
 338                 /* it's critical part, use endless loop */
 339                 /* we have no room to fail */
 340                 mfile->disconnected_f_op = mfile->file->f_op;
 341
 342                 spin_lock(&shutdown_lock);
 343                 list_add(&mfile->shutdown_list, &shutdown_files);
 344                 spin_unlock(&shutdown_lock);
 345
 346                 mfile->file->f_op = &snd_shutdown_f_ops;
 347                 fops_get(mfile->file->f_op);
 348
 349                 mfile = mfile->next;
 350         }
 351         spin_unlock(&card->files_lock);
 352
 353         /* phase 3: notify all connected devices about disconnection */
 354         /* at this point, they cannot respond to any calls except release() */
 355
 356 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 357         if (snd_mixer_oss_notify_callback)
 358                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 359 #endif
 360
 361         /* notify all devices that we are disconnected */
 362         err = snd_device_disconnect_all(card);
 363         if (err < 0)
 364                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 365
 366         snd_info_card_disconnect(card);
 367 #ifndef CONFIG_SYSFS_DEPRECATED
 368         if (card->card_dev) {
 369                 device_unregister(card->card_dev);
 370                 card->card_dev = NULL;
 371         }
 372 #endif
 373 #ifdef CONFIG_PM
 374         wake_up(&card->power_sleep);
 375 #endif
 376         return 0;
 377 }
 378
 379 EXPORT_SYMBOL(snd_card_disconnect);
 380
 381 /**
 382  *  snd_card_free - frees given soundcard structure
 383  *  @card: soundcard structure
 384  *
 385  *  This function releases the soundcard structure and the all assigned
 386  *  devices automatically.  That is, you don't have to release the devices
 387  *  by yourself.
 388  *
 389  *  Returns zero. Frees all associated devices and frees the control
 390  *  interface associated to given soundcard.
 391  */
 392 static int snd_card_do_free(struct snd_card *card)
 393 {
 394 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 395         if (snd_mixer_oss_notify_callback)
 396                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 397 #endif
 398         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
 399                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
 400                 /* Fatal, but this situation should never occur */
 401         }
 402         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
 403                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
 404                 /* Fatal, but this situation should never occur */
 405         }
 406         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
 407                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
 408                 /* Fatal, but this situation should never occur */
 409         }
 410         if (card->private_free)
 411                 card->private_free(card);
 412         snd_info_free_entry(card->proc_id);
 413         if (snd_info_card_free(card) < 0) {
 414                 snd_printk(KERN_WARNING "unable to free card info\n");
 415                 /* Not fatal error */
 416         }
 417         kfree(card);
 418         return 0;
 419 }
 420
 421 int snd_card_free_when_closed(struct snd_card *card)
 422 {
 423         int free_now = 0;
 424         int ret = snd_card_disconnect(card);
 425         if (ret)
 426                 return ret;
 427
 428         spin_lock(&card->files_lock);
 429         if (card->files == NULL)
 430                 free_now = 1;
 431         else
 432                 card->free_on_last_close = 1;
 433         spin_unlock(&card->files_lock);
 434
 435         if (free_now)
 436                 snd_card_do_free(card);
 437         return 0;
 438 }
 439
 440 EXPORT_SYMBOL(snd_card_free_when_closed);
 441
 442 int snd_card_free(struct snd_card *card)
 443 {
 444         int ret = snd_card_disconnect(card);
 445         if (ret)
 446                 return ret;
 447
 448         /* wait, until all devices are ready for the free operation */
 449         wait_event(card->shutdown_sleep, card->files == NULL);
 450         snd_card_do_free(card);
 451         return 0;
 452 }
 453
 454 EXPORT_SYMBOL(snd_card_free);
 455
 456 static void choose_default_id(struct snd_card *card)
 457 {
 458         int i, len, idx_flag = 0, loops = SNDRV_CARDS;
 459         char *id, *spos;
 460
 461         id = spos = card->shortname;
 462         while (*id != '\0') {
 463                 if (*id == ' ')
 464                         spos = id + 1;
 465                 id++;
 466         }
 467         id = card->id;
 468         while (*spos != '\0' && !isalnum(*spos))
 469                 spos++;
 470         if (isdigit(*spos))
 471                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
 472         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 473                 if (isalnum(*spos))
 474                         *id++ = *spos;
 475                 spos++;
 476         }
 477         *id = '\0';
 478
 479         id = card->id;
 480
 481         if (*id == '\0')
 482                 strcpy(id, "default");
 483
 484         while (1) {
 485                 if (loops-- == 0) {
 486                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
 487                         strcpy(card->id, card->proc_root->name);
 488                         return;
 489                 }
 490                 if (!snd_info_check_reserved_words(id))
 491                         goto __change;
 492                 for (i = 0; i < snd_ecards_limit; i++) {
 493                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
 494                                 goto __change;
 495                 }
 496                 break;
 497
 498               __change:
 499                 len = strlen(id);
 500                 if (idx_flag) {
 501                         if (id[len-1] != '9')
 502                                 id[len-1]++;
 503                         else
 504                                 id[len-1] = 'A';
 505                 } else if ((size_t)len <= sizeof(card->id) - 3) {
 506                         strcat(id, "_1");
 507                         idx_flag++;
 508                 } else {
 509                         spos = id + len - 2;
 510                         if ((size_t)len <= sizeof(card->id) - 2)
 511                                 spos++;
 512                         *spos++ = '_';
 513                         *spos++ = '1';
 514                         *spos++ = '\0';
 515                         idx_flag++;
 516                 }
 517         }
 518 }
 519
 520 /**
 521  *  snd_card_register - register the soundcard
 522  *  @card: soundcard structure
 523  *
 524  *  This function registers all the devices assigned to the soundcard.
 525  *  Until calling this, the ALSA control interface is blocked from the
 526  *  external accesses.  Thus, you should call this function at the end
 527  *  of the initialization of the card.
 528  *
 529  *  Returns zero otherwise a negative error code if the registrain failed.
 530  */
 531 int snd_card_register(struct snd_card *card)
 532 {
 533         int err;
 534
 535         snd_assert(card != NULL, return -EINVAL);
 536 #ifndef CONFIG_SYSFS_DEPRECATED
 537         if (!card->card_dev) {
 538                 card->card_dev = device_create(sound_class, card->dev, 0,
 539                                                "card%i", card->number);
 540                 if (IS_ERR(card->card_dev))
 541                         card->card_dev = NULL;
 542         }
 543 #endif
 544         if ((err = snd_device_register_all(card)) < 0)
 545                 return err;
 546         mutex_lock(&snd_card_mutex);
 547         if (snd_cards[card->number]) {
 548                 /* already registered */
 549                 mutex_unlock(&snd_card_mutex);
 550                 return 0;
 551         }
 552         if (card->id[0] == '\0')
 553                 choose_default_id(card);
 554         snd_cards[card->number] = card;
 555         mutex_unlock(&snd_card_mutex);
 556         init_info_for_card(card);
 557 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 558         if (snd_mixer_oss_notify_callback)
 559                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 560 #endif
 561         return 0;
 562 }
 563
 564 EXPORT_SYMBOL(snd_card_register);
 565
 566 #ifdef CONFIG_PROC_FS
 567 static struct snd_info_entry *snd_card_info_entry;
 568
 569 static void snd_card_info_read(struct snd_info_entry *entry,
 570                                struct snd_info_buffer *buffer)
 571 {
 572         int idx, count;
 573         struct snd_card *card;
 574
 575         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 576                 mutex_lock(&snd_card_mutex);
 577                 if ((card = snd_cards[idx]) != NULL) {
 578                         count++;
 579                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 580                                         idx,
 581                                         card->id,
 582                                         card->driver,
 583                                         card->shortname);
 584                         snd_iprintf(buffer, "                      %s\n",
 585                                         card->longname);
 586                 }
 587                 mutex_unlock(&snd_card_mutex);
 588         }
 589         if (!count)
 590                 snd_iprintf(buffer, "--- no soundcards ---\n");
 591 }
 592
 593 #ifdef CONFIG_SND_OSSEMUL
 594
 595 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 596 {
 597         int idx, count;
 598         struct snd_card *card;
 599
 600         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 601                 mutex_lock(&snd_card_mutex);
 602                 if ((card = snd_cards[idx]) != NULL) {
 603                         count++;
 604                         snd_iprintf(buffer, "%s\n", card->longname);
 605                 }
 606                 mutex_unlock(&snd_card_mutex);
 607         }
 608         if (!count) {
 609                 snd_iprintf(buffer, "--- no soundcards ---\n");
 610         }
 611 }
 612
 613 #endif
 614
 615 #ifdef MODULE
 616 static struct snd_info_entry *snd_card_module_info_entry;
 617 static void snd_card_module_info_read(struct snd_info_entry *entry,
 618                                       struct snd_info_buffer *buffer)
 619 {
 620         int idx;
 621         struct snd_card *card;
 622
 623         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 624                 mutex_lock(&snd_card_mutex);
 625                 if ((card = snd_cards[idx]) != NULL)
 626                         snd_iprintf(buffer, "%2i %s\n",
 627                                     idx, card->module->name);
 628                 mutex_unlock(&snd_card_mutex);
 629         }
 630 }
 631 #endif
 632
 633 int __init snd_card_info_init(void)
 634 {
 635         struct snd_info_entry *entry;
 636
 637         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 638         if (! entry)
 639                 return -ENOMEM;
 640         entry->c.text.read = snd_card_info_read;
 641         if (snd_info_register(entry) < 0) {
 642                 snd_info_free_entry(entry);
 643                 return -ENOMEM;
 644         }
 645         snd_card_info_entry = entry;
 646
 647 #ifdef MODULE
 648         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 649         if (entry) {
 650                 entry->c.text.read = snd_card_module_info_read;
 651                 if (snd_info_register(entry) < 0)
 652                         snd_info_free_entry(entry);
 653                 else
 654                         snd_card_module_info_entry = entry;
 655         }
 656 #endif
 657
 658         return 0;
 659 }
 660
 661 int __exit snd_card_info_done(void)
 662 {
 663         snd_info_free_entry(snd_card_info_entry);
 664 #ifdef MODULE
 665         snd_info_free_entry(snd_card_module_info_entry);
 666 #endif
 667         return 0;
 668 }
 669
 670 #endif /* CONFIG_PROC_FS */
 671
 672 /**
 673  *  snd_component_add - add a component string
 674  *  @card: soundcard structure
 675  *  @component: the component id string
 676  *
 677  *  This function adds the component id string to the supported list.
 678  *  The component can be referred from the alsa-lib.
 679  *
 680  *  Returns zero otherwise a negative error code.
 681  */
 682
 683 int snd_component_add(struct snd_card *card, const char *component)
 684 {
 685         char *ptr;
 686         int len = strlen(component);
 687
 688         ptr = strstr(card->components, component);
 689         if (ptr != NULL) {
 690                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 691                         return 1;
 692         }
 693         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 694                 snd_BUG();
 695                 return -ENOMEM;
 696         }
 697         if (card->components[0] != '\0')
 698                 strcat(card->components, " ");
 699         strcat(card->components, component);
 700         return 0;
 701 }
 702
 703 EXPORT_SYMBOL(snd_component_add);
 704
 705 /**
 706  *  snd_card_file_add - add the file to the file list of the card
 707  *  @card: soundcard structure
 708  *  @file: file pointer
 709  *
 710  *  This function adds the file to the file linked-list of the card.
 711  *  This linked-list is used to keep tracking the connection state,
 712  *  and to avoid the release of busy resources by hotplug.
 713  *
 714  *  Returns zero or a negative error code.
 715  */
 716 int snd_card_file_add(struct snd_card *card, struct file *file)
 717 {
 718         struct snd_monitor_file *mfile;
 719
 720         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 721         if (mfile == NULL)
 722                 return -ENOMEM;
 723         mfile->file = file;
 724         mfile->disconnected_f_op = NULL;
 725         mfile->next = NULL;
 726         spin_lock(&card->files_lock);
 727         if (card->shutdown) {
 728                 spin_unlock(&card->files_lock);
 729                 kfree(mfile);
 730                 return -ENODEV;
 731         }
 732         mfile->next = card->files;
 733         card->files = mfile;
 734         spin_unlock(&card->files_lock);
 735         return 0;
 736 }
 737
 738 EXPORT_SYMBOL(snd_card_file_add);
 739
 740 /**
 741  *  snd_card_file_remove - remove the file from the file list
 742  *  @card: soundcard structure
 743  *  @file: file pointer
 744  *
 745  *  This function removes the file formerly added to the card via
 746  *  snd_card_file_add() function.
 747  *  If all files are removed and snd_card_free_when_closed() was
 748  *  called beforehand, it processes the pending release of
 749  *  resources.
 750  *
 751  *  Returns zero or a negative error code.
 752  */
 753 int snd_card_file_remove(struct snd_card *card, struct file *file)
 754 {
 755         struct snd_monitor_file *mfile, *pfile = NULL;
 756         int last_close = 0;
 757
 758         spin_lock(&card->files_lock);
 759         mfile = card->files;
 760         while (mfile) {
 761                 if (mfile->file == file) {
 762                         if (pfile)
 763                                 pfile->next = mfile->next;
 764                         else
 765                                 card->files = mfile->next;
 766                         break;
 767                 }
 768                 pfile = mfile;
 769                 mfile = mfile->next;
 770         }
 771         if (mfile && mfile->disconnected_f_op) {
 772                 fops_put(mfile->disconnected_f_op);
 773                 spin_lock(&shutdown_lock);
 774                 list_del(&mfile->shutdown_list);
 775                 spin_unlock(&shutdown_lock);
 776         }
 777         if (card->files == NULL)
 778                 last_close = 1;
 779         spin_unlock(&card->files_lock);
 780         if (last_close) {
 781                 wake_up(&card->shutdown_sleep);
 782                 if (card->free_on_last_close)
 783                         snd_card_do_free(card);
 784         }
 785         if (!mfile) {
 786                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 787                 return -ENOENT;
 788         }
 789         kfree(mfile);
 790         return 0;
 791 }
 792
 793 EXPORT_SYMBOL(snd_card_file_remove);
 794
 795 #ifdef CONFIG_PM
 796 /**
 797  *  snd_power_wait - wait until the power-state is changed.
 798  *  @card: soundcard structure
 799  *  @power_state: expected power state
 800  *
 801  *  Waits until the power-state is changed.
 802  *
 803  *  Note: the power lock must be active before call.
 804  */
 805 int snd_power_wait(struct snd_card *card, unsigned int power_state)
 806 {
 807         wait_queue_t wait;
 808         int result = 0;
 809
 810         /* fastpath */
 811         if (snd_power_get_state(card) == power_state)
 812                 return 0;
 813         init_waitqueue_entry(&wait, current);
 814         add_wait_queue(&card->power_sleep, &wait);
 815         while (1) {
 816                 if (card->shutdown) {
 817                         result = -ENODEV;
 818                         break;
 819                 }
 820                 if (snd_power_get_state(card) == power_state)
 821                         break;
 822                 set_current_state(TASK_UNINTERRUPTIBLE);
 823                 snd_power_unlock(card);
 824                 schedule_timeout(30 * HZ);
 825                 snd_power_lock(card);
 826         }
 827         remove_wait_queue(&card->power_sleep, &wait);
 828         return result;
 829 }
 830
 831 EXPORT_SYMBOL(snd_power_wait);
 832 #endif /* CONFIG_PM */