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