SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 = 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 static void snd_card_free_thread(void * __card);
  85
  86 /**
  87  *  snd_card_new - create and initialize a soundcard structure
  88  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
  89  *  @xid: card identification (ASCII string)
  90  *  @module: top level module for locking
  91  *  @extra_size: allocate this extra size after the main soundcard structure
  92  *
  93  *  Creates and initializes a soundcard structure.
  94  *
  95  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
  96  *  (which is blocked until snd_card_register function is called).
  97  */
  98 struct snd_card *snd_card_new(int idx, const char *xid,
  99                          struct module *module, int extra_size)
 100 {
 101         struct snd_card *card;
 102         int err;
 103
 104         if (extra_size < 0)
 105                 extra_size = 0;
 106         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 107         if (card == NULL)
 108                 return NULL;
 109         if (xid) {
 110                 if (!snd_info_check_reserved_words(xid))
 111                         goto __error;
 112                 strlcpy(card->id, xid, sizeof(card->id));
 113         }
 114         err = 0;
 115         write_lock(&snd_card_rwlock);
 116         if (idx < 0) {
 117                 int idx2;
 118                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
 119                         if (~snd_cards_lock & idx & 1<<idx2) {
 120                                 idx = idx2;
 121                                 if (idx >= snd_ecards_limit)
 122                                         snd_ecards_limit = idx + 1;
 123                                 break;
 124                         }
 125         } else if (idx < snd_ecards_limit) {
 126                 if (snd_cards_lock & (1 << idx))
 127                         err = -ENODEV;  /* invalid */
 128         } else if (idx < SNDRV_CARDS)
 129                 snd_ecards_limit = idx + 1; /* increase the limit */
 130         else
 131                 err = -ENODEV;
 132         if (idx < 0 || err < 0) {
 133                 write_unlock(&snd_card_rwlock);
 134                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
 135                 goto __error;
 136         }
 137         snd_cards_lock |= 1 << idx;             /* lock it */
 138         write_unlock(&snd_card_rwlock);
 139         card->number = idx;
 140         card->module = module;
 141         INIT_LIST_HEAD(&card->devices);
 142         init_rwsem(&card->controls_rwsem);
 143         rwlock_init(&card->ctl_files_rwlock);
 144         INIT_LIST_HEAD(&card->controls);
 145         INIT_LIST_HEAD(&card->ctl_files);
 146         spin_lock_init(&card->files_lock);
 147         init_waitqueue_head(&card->shutdown_sleep);
 148         INIT_WORK(&card->free_workq, snd_card_free_thread, card);
 149 #ifdef CONFIG_PM
 150         mutex_init(&card->power_lock);
 151         init_waitqueue_head(&card->power_sleep);
 152 #endif
 153         /* the control interface cannot be accessed from the user space until */
 154         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 155         if ((err = snd_ctl_create(card)) < 0) {
 156                 snd_printd("unable to register control minors\n");
 157                 goto __error;
 158         }
 159         if ((err = snd_info_card_create(card)) < 0) {
 160                 snd_printd("unable to create card info\n");
 161                 goto __error_ctl;
 162         }
 163         if (extra_size > 0)
 164                 card->private_data = (char *)card + sizeof(struct snd_card);
 165         return card;
 166
 167       __error_ctl:
 168         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
 169       __error:
 170         kfree(card);
 171         return NULL;
 172 }
 173
 174 EXPORT_SYMBOL(snd_card_new);
 175
 176 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
 177 {
 178         return -ENODEV;
 179 }
 180
 181 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
 182                                    size_t count, loff_t *offset)
 183 {
 184         return -ENODEV;
 185 }
 186
 187 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
 188                                     size_t count, loff_t *offset)
 189 {
 190         return -ENODEV;
 191 }
 192
 193 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
 194 {
 195         return POLLERR | POLLNVAL;
 196 }
 197
 198 static long snd_disconnect_ioctl(struct file *file,
 199                                  unsigned int cmd, unsigned long arg)
 200 {
 201         return -ENODEV;
 202 }
 203
 204 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
 205 {
 206         return -ENODEV;
 207 }
 208
 209 static int snd_disconnect_fasync(int fd, struct file *file, int on)
 210 {
 211         return -ENODEV;
 212 }
 213
 214 /**
 215  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 216  *  @card: soundcard structure
 217  *
 218  *  Disconnects all APIs from the file-operations (user space).
 219  *
 220  *  Returns zero, otherwise a negative error code.
 221  *
 222  *  Note: The current implementation replaces all active file->f_op with special
 223  *        dummy file operations (they do nothing except release).
 224  */
 225 int snd_card_disconnect(struct snd_card *card)
 226 {
 227         struct snd_monitor_file *mfile;
 228         struct file *file;
 229         struct snd_shutdown_f_ops *s_f_ops;
 230         struct file_operations *f_ops;
 231         const struct file_operations *old_f_ops;
 232         int err;
 233
 234         spin_lock(&card->files_lock);
 235         if (card->shutdown) {
 236                 spin_unlock(&card->files_lock);
 237                 return 0;
 238         }
 239         card->shutdown = 1;
 240         spin_unlock(&card->files_lock);
 241
 242         /* phase 1: disable fops (user space) operations for ALSA API */
 243         write_lock(&snd_card_rwlock);
 244         snd_cards[card->number] = NULL;
 245         write_unlock(&snd_card_rwlock);
 246
 247         /* phase 2: replace file->f_op with special dummy operations */
 248
 249         spin_lock(&card->files_lock);
 250         mfile = card->files;
 251         while (mfile) {
 252                 file = mfile->file;
 253
 254                 /* it's critical part, use endless loop */
 255                 /* we have no room to fail */
 256                 s_f_ops = kmalloc(sizeof(struct snd_shutdown_f_ops), GFP_ATOMIC);
 257                 if (s_f_ops == NULL)
 258                         panic("Atomic allocation failed for snd_shutdown_f_ops!");
 259
 260                 f_ops = &s_f_ops->f_ops;
 261
 262                 memset(f_ops, 0, sizeof(*f_ops));
 263                 f_ops->owner = file->f_op->owner;
 264                 f_ops->release = file->f_op->release;
 265                 f_ops->llseek = snd_disconnect_llseek;
 266                 f_ops->read = snd_disconnect_read;
 267                 f_ops->write = snd_disconnect_write;
 268                 f_ops->poll = snd_disconnect_poll;
 269                 f_ops->unlocked_ioctl = snd_disconnect_ioctl;
 270 #ifdef CONFIG_COMPAT
 271                 f_ops->compat_ioctl = snd_disconnect_ioctl;
 272 #endif
 273                 f_ops->mmap = snd_disconnect_mmap;
 274                 f_ops->fasync = snd_disconnect_fasync;
 275
 276                 s_f_ops->next = card->s_f_ops;
 277                 card->s_f_ops = s_f_ops;
 278
 279                 f_ops = fops_get(f_ops);
 280
 281                 old_f_ops = file->f_op;
 282                 file->f_op = f_ops;     /* must be atomic */
 283                 fops_put(old_f_ops);
 284
 285                 mfile = mfile->next;
 286         }
 287         spin_unlock(&card->files_lock);
 288
 289         /* phase 3: notify all connected devices about disconnection */
 290         /* at this point, they cannot respond to any calls except release() */
 291
 292 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 293         if (snd_mixer_oss_notify_callback)
 294                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 295 #endif
 296
 297         /* notify all devices that we are disconnected */
 298         err = snd_device_disconnect_all(card);
 299         if (err < 0)
 300                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 301
 302         return 0;
 303 }
 304
 305 EXPORT_SYMBOL(snd_card_disconnect);
 306
 307 /**
 308  *  snd_card_free - frees given soundcard structure
 309  *  @card: soundcard structure
 310  *
 311  *  This function releases the soundcard structure and the all assigned
 312  *  devices automatically.  That is, you don't have to release the devices
 313  *  by yourself.
 314  *
 315  *  Returns zero. Frees all associated devices and frees the control
 316  *  interface associated to given soundcard.
 317  */
 318 int snd_card_free(struct snd_card *card)
 319 {
 320         struct snd_shutdown_f_ops *s_f_ops;
 321
 322         if (card == NULL)
 323                 return -EINVAL;
 324         write_lock(&snd_card_rwlock);
 325         snd_cards[card->number] = NULL;
 326         write_unlock(&snd_card_rwlock);
 327
 328 #ifdef CONFIG_PM
 329         wake_up(&card->power_sleep);
 330 #endif
 331         /* wait, until all devices are ready for the free operation */
 332         wait_event(card->shutdown_sleep, card->files == NULL);
 333
 334 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 335         if (snd_mixer_oss_notify_callback)
 336                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 337 #endif
 338         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
 339                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
 340                 /* Fatal, but this situation should never occur */
 341         }
 342         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
 343                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
 344                 /* Fatal, but this situation should never occur */
 345         }
 346         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
 347                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
 348                 /* Fatal, but this situation should never occur */
 349         }
 350         if (card->private_free)
 351                 card->private_free(card);
 352         snd_info_unregister(card->proc_id);
 353         if (snd_info_card_free(card) < 0) {
 354                 snd_printk(KERN_WARNING "unable to free card info\n");
 355                 /* Not fatal error */
 356         }
 357         while (card->s_f_ops) {
 358                 s_f_ops = card->s_f_ops;
 359                 card->s_f_ops = s_f_ops->next;
 360                 kfree(s_f_ops);
 361         }
 362         write_lock(&snd_card_rwlock);
 363         snd_cards_lock &= ~(1 << card->number);
 364         write_unlock(&snd_card_rwlock);
 365         kfree(card);
 366         return 0;
 367 }
 368
 369 EXPORT_SYMBOL(snd_card_free);
 370
 371 static void snd_card_free_thread(void * __card)
 372 {
 373         struct snd_card *card = __card;
 374         struct module * module = card->module;
 375
 376         if (!try_module_get(module)) {
 377                 snd_printk(KERN_ERR "unable to lock toplevel module for card %i in free thread\n", card->number);
 378                 module = NULL;
 379         }
 380
 381         snd_card_free(card);
 382
 383         module_put(module);
 384 }
 385
 386 /**
 387  *  snd_card_free_in_thread - call snd_card_free() in thread
 388  *  @card: soundcard structure
 389  *
 390  *  This function schedules the call of snd_card_free() function in a
 391  *  work queue.  When all devices are released (non-busy), the work
 392  *  is woken up and calls snd_card_free().
 393  *
 394  *  When a card can be disconnected at any time by hotplug service,
 395  *  this function should be used in disconnect (or detach) callback
 396  *  instead of calling snd_card_free() directly.
 397  *
 398  *  Returns - zero otherwise a negative error code if the start of thread failed.
 399  */
 400 int snd_card_free_in_thread(struct snd_card *card)
 401 {
 402         if (card->files == NULL) {
 403                 snd_card_free(card);
 404                 return 0;
 405         }
 406
 407         if (schedule_work(&card->free_workq))
 408                 return 0;
 409
 410         snd_printk(KERN_ERR "schedule_work() failed in snd_card_free_in_thread for card %i\n", card->number);
 411         /* try to free the structure immediately */
 412         snd_card_free(card);
 413         return -EFAULT;
 414 }
 415
 416 EXPORT_SYMBOL(snd_card_free_in_thread);
 417
 418 static void choose_default_id(struct snd_card *card)
 419 {
 420         int i, len, idx_flag = 0, loops = SNDRV_CARDS;
 421         char *id, *spos;
 422
 423         id = spos = card->shortname;
 424         while (*id != '\0') {
 425                 if (*id == ' ')
 426                         spos = id + 1;
 427                 id++;
 428         }
 429         id = card->id;
 430         while (*spos != '\0' && !isalnum(*spos))
 431                 spos++;
 432         if (isdigit(*spos))
 433                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
 434         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 435                 if (isalnum(*spos))
 436                         *id++ = *spos;
 437                 spos++;
 438         }
 439         *id = '\0';
 440
 441         id = card->id;
 442
 443         if (*id == '\0')
 444                 strcpy(id, "default");
 445
 446         while (1) {
 447                 if (loops-- == 0) {
 448                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
 449                         strcpy(card->id, card->proc_root->name);
 450                         return;
 451                 }
 452                 if (!snd_info_check_reserved_words(id))
 453                         goto __change;
 454                 for (i = 0; i < snd_ecards_limit; i++) {
 455                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
 456                                 goto __change;
 457                 }
 458                 break;
 459
 460               __change:
 461                 len = strlen(id);
 462                 if (idx_flag) {
 463                         if (id[len-1] != '9')
 464                                 id[len-1]++;
 465                         else
 466                                 id[len-1] = 'A';
 467                 } else if ((size_t)len <= sizeof(card->id) - 3) {
 468                         strcat(id, "_1");
 469                         idx_flag++;
 470                 } else {
 471                         spos = id + len - 2;
 472                         if ((size_t)len <= sizeof(card->id) - 2)
 473                                 spos++;
 474                         *spos++ = '_';
 475                         *spos++ = '1';
 476                         *spos++ = '\0';
 477                         idx_flag++;
 478                 }
 479         }
 480 }
 481
 482 /**
 483  *  snd_card_register - register the soundcard
 484  *  @card: soundcard structure
 485  *
 486  *  This function registers all the devices assigned to the soundcard.
 487  *  Until calling this, the ALSA control interface is blocked from the
 488  *  external accesses.  Thus, you should call this function at the end
 489  *  of the initialization of the card.
 490  *
 491  *  Returns zero otherwise a negative error code if the registrain failed.
 492  */
 493 int snd_card_register(struct snd_card *card)
 494 {
 495         int err;
 496
 497         snd_assert(card != NULL, return -EINVAL);
 498         if ((err = snd_device_register_all(card)) < 0)
 499                 return err;
 500         write_lock(&snd_card_rwlock);
 501         if (snd_cards[card->number]) {
 502                 /* already registered */
 503                 write_unlock(&snd_card_rwlock);
 504                 return 0;
 505         }
 506         if (card->id[0] == '\0')
 507                 choose_default_id(card);
 508         snd_cards[card->number] = card;
 509         write_unlock(&snd_card_rwlock);
 510         init_info_for_card(card);
 511 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 512         if (snd_mixer_oss_notify_callback)
 513                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 514 #endif
 515         return 0;
 516 }
 517
 518 EXPORT_SYMBOL(snd_card_register);
 519
 520 #ifdef CONFIG_PROC_FS
 521 static struct snd_info_entry *snd_card_info_entry = NULL;
 522
 523 static void snd_card_info_read(struct snd_info_entry *entry,
 524                                struct snd_info_buffer *buffer)
 525 {
 526         int idx, count;
 527         struct snd_card *card;
 528
 529         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 530                 read_lock(&snd_card_rwlock);
 531                 if ((card = snd_cards[idx]) != NULL) {
 532                         count++;
 533                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 534                                         idx,
 535                                         card->id,
 536                                         card->driver,
 537                                         card->shortname);
 538                         snd_iprintf(buffer, "                      %s\n",
 539                                         card->longname);
 540                 }
 541                 read_unlock(&snd_card_rwlock);
 542         }
 543         if (!count)
 544                 snd_iprintf(buffer, "--- no soundcards ---\n");
 545 }
 546
 547 #ifdef CONFIG_SND_OSSEMUL
 548
 549 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 550 {
 551         int idx, count;
 552         struct snd_card *card;
 553
 554         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 555                 read_lock(&snd_card_rwlock);
 556                 if ((card = snd_cards[idx]) != NULL) {
 557                         count++;
 558                         snd_iprintf(buffer, "%s\n", card->longname);
 559                 }
 560                 read_unlock(&snd_card_rwlock);
 561         }
 562         if (!count) {
 563                 snd_iprintf(buffer, "--- no soundcards ---\n");
 564         }
 565 }
 566
 567 #endif
 568
 569 #ifdef MODULE
 570 static struct snd_info_entry *snd_card_module_info_entry;
 571 static void snd_card_module_info_read(struct snd_info_entry *entry,
 572                                       struct snd_info_buffer *buffer)
 573 {
 574         int idx;
 575         struct snd_card *card;
 576
 577         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 578                 read_lock(&snd_card_rwlock);
 579                 if ((card = snd_cards[idx]) != NULL)
 580                         snd_iprintf(buffer, "%2i %s\n",
 581                                     idx, card->module->name);
 582                 read_unlock(&snd_card_rwlock);
 583         }
 584 }
 585 #endif
 586
 587 int __init snd_card_info_init(void)
 588 {
 589         struct snd_info_entry *entry;
 590
 591         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 592         if (! entry)
 593                 return -ENOMEM;
 594         entry->c.text.read = snd_card_info_read;
 595         if (snd_info_register(entry) < 0) {
 596                 snd_info_free_entry(entry);
 597                 return -ENOMEM;
 598         }
 599         snd_card_info_entry = entry;
 600
 601 #ifdef MODULE
 602         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 603         if (entry) {
 604                 entry->c.text.read = snd_card_module_info_read;
 605                 if (snd_info_register(entry) < 0)
 606                         snd_info_free_entry(entry);
 607                 else
 608                         snd_card_module_info_entry = entry;
 609         }
 610 #endif
 611
 612         return 0;
 613 }
 614
 615 int __exit snd_card_info_done(void)
 616 {
 617         snd_info_unregister(snd_card_info_entry);
 618 #ifdef MODULE
 619         snd_info_unregister(snd_card_module_info_entry);
 620 #endif
 621         return 0;
 622 }
 623
 624 #endif /* CONFIG_PROC_FS */
 625
 626 /**
 627  *  snd_component_add - add a component string
 628  *  @card: soundcard structure
 629  *  @component: the component id string
 630  *
 631  *  This function adds the component id string to the supported list.
 632  *  The component can be referred from the alsa-lib.
 633  *
 634  *  Returns zero otherwise a negative error code.
 635  */
 636
 637 int snd_component_add(struct snd_card *card, const char *component)
 638 {
 639         char *ptr;
 640         int len = strlen(component);
 641
 642         ptr = strstr(card->components, component);
 643         if (ptr != NULL) {
 644                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 645                         return 1;
 646         }
 647         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 648                 snd_BUG();
 649                 return -ENOMEM;
 650         }
 651         if (card->components[0] != '\0')
 652                 strcat(card->components, " ");
 653         strcat(card->components, component);
 654         return 0;
 655 }
 656
 657 EXPORT_SYMBOL(snd_component_add);
 658
 659 /**
 660  *  snd_card_file_add - add the file to the file list of the card
 661  *  @card: soundcard structure
 662  *  @file: file pointer
 663  *
 664  *  This function adds the file to the file linked-list of the card.
 665  *  This linked-list is used to keep tracking the connection state,
 666  *  and to avoid the release of busy resources by hotplug.
 667  *
 668  *  Returns zero or a negative error code.
 669  */
 670 int snd_card_file_add(struct snd_card *card, struct file *file)
 671 {
 672         struct snd_monitor_file *mfile;
 673
 674         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 675         if (mfile == NULL)
 676                 return -ENOMEM;
 677         mfile->file = file;
 678         mfile->next = NULL;
 679         spin_lock(&card->files_lock);
 680         if (card->shutdown) {
 681                 spin_unlock(&card->files_lock);
 682                 kfree(mfile);
 683                 return -ENODEV;
 684         }
 685         mfile->next = card->files;
 686         card->files = mfile;
 687         spin_unlock(&card->files_lock);
 688         return 0;
 689 }
 690
 691 EXPORT_SYMBOL(snd_card_file_add);
 692
 693 /**
 694  *  snd_card_file_remove - remove the file from the file list
 695  *  @card: soundcard structure
 696  *  @file: file pointer
 697  *
 698  *  This function removes the file formerly added to the card via
 699  *  snd_card_file_add() function.
 700  *  If all files are removed and the release of the card is
 701  *  scheduled, it will wake up the the thread to call snd_card_free()
 702  *  (see snd_card_free_in_thread() function).
 703  *
 704  *  Returns zero or a negative error code.
 705  */
 706 int snd_card_file_remove(struct snd_card *card, struct file *file)
 707 {
 708         struct snd_monitor_file *mfile, *pfile = NULL;
 709
 710         spin_lock(&card->files_lock);
 711         mfile = card->files;
 712         while (mfile) {
 713                 if (mfile->file == file) {
 714                         if (pfile)
 715                                 pfile->next = mfile->next;
 716                         else
 717                                 card->files = mfile->next;
 718                         break;
 719                 }
 720                 pfile = mfile;
 721                 mfile = mfile->next;
 722         }
 723         spin_unlock(&card->files_lock);
 724         if (card->files == NULL)
 725                 wake_up(&card->shutdown_sleep);
 726         if (!mfile) {
 727                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 728                 return -ENOENT;
 729         }
 730         kfree(mfile);
 731         return 0;
 732 }
 733
 734 EXPORT_SYMBOL(snd_card_file_remove);
 735
 736 #ifdef CONFIG_PM
 737 /**
 738  *  snd_power_wait - wait until the power-state is changed.
 739  *  @card: soundcard structure
 740  *  @power_state: expected power state
 741  *
 742  *  Waits until the power-state is changed.
 743  *
 744  *  Note: the power lock must be active before call.
 745  */
 746 int snd_power_wait(struct snd_card *card, unsigned int power_state)
 747 {
 748         wait_queue_t wait;
 749         int result = 0;
 750
 751         /* fastpath */
 752         if (snd_power_get_state(card) == power_state)
 753                 return 0;
 754         init_waitqueue_entry(&wait, current);
 755         add_wait_queue(&card->power_sleep, &wait);
 756         while (1) {
 757                 if (card->shutdown) {
 758                         result = -ENODEV;
 759                         break;
 760                 }
 761                 if (snd_power_get_state(card) == power_state)
 762                         break;
 763                 set_current_state(TASK_UNINTERRUPTIBLE);
 764                 snd_power_unlock(card);
 765                 schedule_timeout(30 * HZ);
 766                 snd_power_lock(card);
 767         }
 768         remove_wait_queue(&card->power_sleep, &wait);
 769         return result;
 770 }
 771
 772 EXPORT_SYMBOL(snd_power_wait);
 773 #endif /* CONFIG_PM */