sound/core/init.c

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This source file includes following definitions.
module_slot_match
check_empty_slot
get_slot_from_bitmask
default_release
snd_device_initialize
release_card_device
snd_card_new
snd_card_ref
snd_card_locked
snd_disconnect_llseek
snd_disconnect_read
snd_disconnect_write
snd_disconnect_release
snd_disconnect_poll
snd_disconnect_ioctl
snd_disconnect_mmap
snd_disconnect_fasync
snd_card_disconnect
snd_card_disconnect_sync
snd_card_do_free
snd_card_free_when_closed
snd_card_free
retrieve_id_from_card_name
card_id_ok
copy_valid_id_string
snd_card_set_id_no_lock
snd_card_set_id
card_id_show_attr
card_id_store_attr
card_number_show_attr
snd_card_add_dev_attr
snd_card_register
snd_card_info_read
snd_card_info_read_oss
snd_card_module_info_read
snd_card_info_init
snd_component_add
snd_card_file_add
snd_card_file_remove
snd_power_wait
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Initialization routines
   4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   5  */
   6 
   7 #include <linux/init.h>
   8 #include <linux/sched.h>
   9 #include <linux/module.h>
  10 #include <linux/device.h>
  11 #include <linux/file.h>
  12 #include <linux/slab.h>
  13 #include <linux/time.h>
  14 #include <linux/ctype.h>
  15 #include <linux/pm.h>
  16 #include <linux/completion.h>
  17 
  18 #include <sound/core.h>
  19 #include <sound/control.h>
  20 #include <sound/info.h>
  21 
  22 /* monitor files for graceful shutdown (hotplug) */
  23 struct snd_monitor_file {
  24         struct file *file;
  25         const struct file_operations *disconnected_f_op;
  26         struct list_head shutdown_list; /* still need to shutdown */
  27         struct list_head list;  /* link of monitor files */
  28 };
  29 
  30 static DEFINE_SPINLOCK(shutdown_lock);
  31 static LIST_HEAD(shutdown_files);
  32 
  33 static const struct file_operations snd_shutdown_f_ops;
  34 
  35 /* locked for registering/using */
  36 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
  37 static struct snd_card *snd_cards[SNDRV_CARDS];
  38 
  39 static DEFINE_MUTEX(snd_card_mutex);
  40 
  41 static char *slots[SNDRV_CARDS];
  42 module_param_array(slots, charp, NULL, 0444);
  43 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
  44 
  45 /* return non-zero if the given index is reserved for the given
  46  * module via slots option
  47  */
  48 static int module_slot_match(struct module *module, int idx)
  49 {
  50         int match = 1;
  51 #ifdef MODULE
  52         const char *s1, *s2;
  53 
  54         if (!module || !*module->name || !slots[idx])
  55                 return 0;
  56 
  57         s1 = module->name;
  58         s2 = slots[idx];
  59         if (*s2 == '!') {
  60                 match = 0; /* negative match */
  61                 s2++;
  62         }
  63         /* compare module name strings
  64          * hyphens are handled as equivalent with underscore
  65          */
  66         for (;;) {
  67                 char c1 = *s1++;
  68                 char c2 = *s2++;
  69                 if (c1 == '-')
  70                         c1 = '_';
  71                 if (c2 == '-')
  72                         c2 = '_';
  73                 if (c1 != c2)
  74                         return !match;
  75                 if (!c1)
  76                         break;
  77         }
  78 #endif /* MODULE */
  79         return match;
  80 }
  81 
  82 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
  83 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
  84 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
  85 #endif
  86 
  87 static int check_empty_slot(struct module *module, int slot)
  88 {
  89         return !slots[slot] || !*slots[slot];
  90 }
  91 
  92 /* return an empty slot number (>= 0) found in the given bitmask @mask.
  93  * @mask == -1 == 0xffffffff means: take any free slot up to 32
  94  * when no slot is available, return the original @mask as is.
  95  */
  96 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
  97                                  struct module *module)
  98 {
  99         int slot;
 100 
 101         for (slot = 0; slot < SNDRV_CARDS; slot++) {
 102                 if (slot < 32 && !(mask & (1U << slot)))
 103                         continue;
 104                 if (!test_bit(slot, snd_cards_lock)) {
 105                         if (check(module, slot))
 106                                 return slot; /* found */
 107                 }
 108         }
 109         return mask; /* unchanged */
 110 }
 111 
 112 /* the default release callback set in snd_device_initialize() below;
 113  * this is just NOP for now, as almost all jobs are already done in
 114  * dev_free callback of snd_device chain instead.
 115  */
 116 static void default_release(struct device *dev)
 117 {
 118 }
 119 
 120 /**
 121  * snd_device_initialize - Initialize struct device for sound devices
 122  * @dev: device to initialize
 123  * @card: card to assign, optional
 124  */
 125 void snd_device_initialize(struct device *dev, struct snd_card *card)
 126 {
 127         device_initialize(dev);
 128         if (card)
 129                 dev->parent = &card->card_dev;
 130         dev->class = sound_class;
 131         dev->release = default_release;
 132 }
 133 EXPORT_SYMBOL_GPL(snd_device_initialize);
 134 
 135 static int snd_card_do_free(struct snd_card *card);
 136 static const struct attribute_group card_dev_attr_group;
 137 
 138 static void release_card_device(struct device *dev)
 139 {
 140         snd_card_do_free(dev_to_snd_card(dev));
 141 }
 142 
 143 /**
 144  *  snd_card_new - create and initialize a soundcard structure
 145  *  @parent: the parent device object
 146  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 147  *  @xid: card identification (ASCII string)
 148  *  @module: top level module for locking
 149  *  @extra_size: allocate this extra size after the main soundcard structure
 150  *  @card_ret: the pointer to store the created card instance
 151  *
 152  *  Creates and initializes a soundcard structure.
 153  *
 154  *  The function allocates snd_card instance via kzalloc with the given
 155  *  space for the driver to use freely.  The allocated struct is stored
 156  *  in the given card_ret pointer.
 157  *
 158  *  Return: Zero if successful or a negative error code.
 159  */
 160 int snd_card_new(struct device *parent, int idx, const char *xid,
 161                     struct module *module, int extra_size,
 162                     struct snd_card **card_ret)
 163 {
 164         struct snd_card *card;
 165         int err;
 166 
 167         if (snd_BUG_ON(!card_ret))
 168                 return -EINVAL;
 169         *card_ret = NULL;
 170 
 171         if (extra_size < 0)
 172                 extra_size = 0;
 173         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 174         if (!card)
 175                 return -ENOMEM;
 176         if (extra_size > 0)
 177                 card->private_data = (char *)card + sizeof(struct snd_card);
 178         if (xid)
 179                 strlcpy(card->id, xid, sizeof(card->id));
 180         err = 0;
 181         mutex_lock(&snd_card_mutex);
 182         if (idx < 0) /* first check the matching module-name slot */
 183                 idx = get_slot_from_bitmask(idx, module_slot_match, module);
 184         if (idx < 0) /* if not matched, assign an empty slot */
 185                 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
 186         if (idx < 0)
 187                 err = -ENODEV;
 188         else if (idx < snd_ecards_limit) {
 189                 if (test_bit(idx, snd_cards_lock))
 190                         err = -EBUSY;   /* invalid */
 191         } else if (idx >= SNDRV_CARDS)
 192                 err = -ENODEV;
 193         if (err < 0) {
 194                 mutex_unlock(&snd_card_mutex);
 195                 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
 196                          idx, snd_ecards_limit - 1, err);
 197                 kfree(card);
 198                 return err;
 199         }
 200         set_bit(idx, snd_cards_lock);           /* lock it */
 201         if (idx >= snd_ecards_limit)
 202                 snd_ecards_limit = idx + 1; /* increase the limit */
 203         mutex_unlock(&snd_card_mutex);
 204         card->dev = parent;
 205         card->number = idx;
 206         card->module = module;
 207         INIT_LIST_HEAD(&card->devices);
 208         init_rwsem(&card->controls_rwsem);
 209         rwlock_init(&card->ctl_files_rwlock);
 210         INIT_LIST_HEAD(&card->controls);
 211         INIT_LIST_HEAD(&card->ctl_files);
 212         spin_lock_init(&card->files_lock);
 213         INIT_LIST_HEAD(&card->files_list);
 214 #ifdef CONFIG_PM
 215         init_waitqueue_head(&card->power_sleep);
 216 #endif
 217         init_waitqueue_head(&card->remove_sleep);
 218 
 219         device_initialize(&card->card_dev);
 220         card->card_dev.parent = parent;
 221         card->card_dev.class = sound_class;
 222         card->card_dev.release = release_card_device;
 223         card->card_dev.groups = card->dev_groups;
 224         card->dev_groups[0] = &card_dev_attr_group;
 225         err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
 226         if (err < 0)
 227                 goto __error;
 228 
 229         snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
 230                  dev_driver_string(card->dev), dev_name(&card->card_dev));
 231 
 232         /* the control interface cannot be accessed from the user space until */
 233         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 234         err = snd_ctl_create(card);
 235         if (err < 0) {
 236                 dev_err(parent, "unable to register control minors\n");
 237                 goto __error;
 238         }
 239         err = snd_info_card_create(card);
 240         if (err < 0) {
 241                 dev_err(parent, "unable to create card info\n");
 242                 goto __error_ctl;
 243         }
 244         *card_ret = card;
 245         return 0;
 246 
 247       __error_ctl:
 248         snd_device_free_all(card);
 249       __error:
 250         put_device(&card->card_dev);
 251         return err;
 252 }
 253 EXPORT_SYMBOL(snd_card_new);
 254 
 255 /**
 256  * snd_card_ref - Get the card object from the index
 257  * @idx: the card index
 258  *
 259  * Returns a card object corresponding to the given index or NULL if not found.
 260  * Release the object via snd_card_unref().
 261  */
 262 struct snd_card *snd_card_ref(int idx)
 263 {
 264         struct snd_card *card;
 265 
 266         mutex_lock(&snd_card_mutex);
 267         card = snd_cards[idx];
 268         if (card)
 269                 get_device(&card->card_dev);
 270         mutex_unlock(&snd_card_mutex);
 271         return card;
 272 }
 273 EXPORT_SYMBOL_GPL(snd_card_ref);
 274 
 275 /* return non-zero if a card is already locked */
 276 int snd_card_locked(int card)
 277 {
 278         int locked;
 279 
 280         mutex_lock(&snd_card_mutex);
 281         locked = test_bit(card, snd_cards_lock);
 282         mutex_unlock(&snd_card_mutex);
 283         return locked;
 284 }
 285 
 286 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
 287 {
 288         return -ENODEV;
 289 }
 290 
 291 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
 292                                    size_t count, loff_t *offset)
 293 {
 294         return -ENODEV;
 295 }
 296 
 297 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
 298                                     size_t count, loff_t *offset)
 299 {
 300         return -ENODEV;
 301 }
 302 
 303 static int snd_disconnect_release(struct inode *inode, struct file *file)
 304 {
 305         struct snd_monitor_file *df = NULL, *_df;
 306 
 307         spin_lock(&shutdown_lock);
 308         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
 309                 if (_df->file == file) {
 310                         df = _df;
 311                         list_del_init(&df->shutdown_list);
 312                         break;
 313                 }
 314         }
 315         spin_unlock(&shutdown_lock);
 316 
 317         if (likely(df)) {
 318                 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
 319                         df->disconnected_f_op->fasync(-1, file, 0);
 320                 return df->disconnected_f_op->release(inode, file);
 321         }
 322 
 323         panic("%s(%p, %p) failed!", __func__, inode, file);
 324 }
 325 
 326 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
 327 {
 328         return EPOLLERR | EPOLLNVAL;
 329 }
 330 
 331 static long snd_disconnect_ioctl(struct file *file,
 332                                  unsigned int cmd, unsigned long arg)
 333 {
 334         return -ENODEV;
 335 }
 336 
 337 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
 338 {
 339         return -ENODEV;
 340 }
 341 
 342 static int snd_disconnect_fasync(int fd, struct file *file, int on)
 343 {
 344         return -ENODEV;
 345 }
 346 
 347 static const struct file_operations snd_shutdown_f_ops =
 348 {
 349         .owner =        THIS_MODULE,
 350         .llseek =       snd_disconnect_llseek,
 351         .read =         snd_disconnect_read,
 352         .write =        snd_disconnect_write,
 353         .release =      snd_disconnect_release,
 354         .poll =         snd_disconnect_poll,
 355         .unlocked_ioctl = snd_disconnect_ioctl,
 356 #ifdef CONFIG_COMPAT
 357         .compat_ioctl = snd_disconnect_ioctl,
 358 #endif
 359         .mmap =         snd_disconnect_mmap,
 360         .fasync =       snd_disconnect_fasync
 361 };
 362 
 363 /**
 364  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 365  *  @card: soundcard structure
 366  *
 367  *  Disconnects all APIs from the file-operations (user space).
 368  *
 369  *  Return: Zero, otherwise a negative error code.
 370  *
 371  *  Note: The current implementation replaces all active file->f_op with special
 372  *        dummy file operations (they do nothing except release).
 373  */
 374 int snd_card_disconnect(struct snd_card *card)
 375 {
 376         struct snd_monitor_file *mfile;
 377 
 378         if (!card)
 379                 return -EINVAL;
 380 
 381         spin_lock(&card->files_lock);
 382         if (card->shutdown) {
 383                 spin_unlock(&card->files_lock);
 384                 return 0;
 385         }
 386         card->shutdown = 1;
 387         spin_unlock(&card->files_lock);
 388 
 389         /* replace file->f_op with special dummy operations */
 390         spin_lock(&card->files_lock);
 391         list_for_each_entry(mfile, &card->files_list, list) {
 392                 /* it's critical part, use endless loop */
 393                 /* we have no room to fail */
 394                 mfile->disconnected_f_op = mfile->file->f_op;
 395 
 396                 spin_lock(&shutdown_lock);
 397                 list_add(&mfile->shutdown_list, &shutdown_files);
 398                 spin_unlock(&shutdown_lock);
 399 
 400                 mfile->file->f_op = &snd_shutdown_f_ops;
 401                 fops_get(mfile->file->f_op);
 402         }
 403         spin_unlock(&card->files_lock); 
 404 
 405         /* notify all connected devices about disconnection */
 406         /* at this point, they cannot respond to any calls except release() */
 407 
 408 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 409         if (snd_mixer_oss_notify_callback)
 410                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 411 #endif
 412 
 413         /* notify all devices that we are disconnected */
 414         snd_device_disconnect_all(card);
 415 
 416         snd_info_card_disconnect(card);
 417         if (card->registered) {
 418                 device_del(&card->card_dev);
 419                 card->registered = false;
 420         }
 421 
 422         /* disable fops (user space) operations for ALSA API */
 423         mutex_lock(&snd_card_mutex);
 424         snd_cards[card->number] = NULL;
 425         clear_bit(card->number, snd_cards_lock);
 426         mutex_unlock(&snd_card_mutex);
 427 
 428 #ifdef CONFIG_PM
 429         wake_up(&card->power_sleep);
 430 #endif
 431         return 0;       
 432 }
 433 EXPORT_SYMBOL(snd_card_disconnect);
 434 
 435 /**
 436  * snd_card_disconnect_sync - disconnect card and wait until files get closed
 437  * @card: card object to disconnect
 438  *
 439  * This calls snd_card_disconnect() for disconnecting all belonging components
 440  * and waits until all pending files get closed.
 441  * It assures that all accesses from user-space finished so that the driver
 442  * can release its resources gracefully.
 443  */
 444 void snd_card_disconnect_sync(struct snd_card *card)
 445 {
 446         int err;
 447 
 448         err = snd_card_disconnect(card);
 449         if (err < 0) {
 450                 dev_err(card->dev,
 451                         "snd_card_disconnect error (%d), skipping sync\n",
 452                         err);
 453                 return;
 454         }
 455 
 456         spin_lock_irq(&card->files_lock);
 457         wait_event_lock_irq(card->remove_sleep,
 458                             list_empty(&card->files_list),
 459                             card->files_lock);
 460         spin_unlock_irq(&card->files_lock);
 461 }
 462 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
 463 
 464 static int snd_card_do_free(struct snd_card *card)
 465 {
 466 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 467         if (snd_mixer_oss_notify_callback)
 468                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 469 #endif
 470         snd_device_free_all(card);
 471         if (card->private_free)
 472                 card->private_free(card);
 473         if (snd_info_card_free(card) < 0) {
 474                 dev_warn(card->dev, "unable to free card info\n");
 475                 /* Not fatal error */
 476         }
 477         if (card->release_completion)
 478                 complete(card->release_completion);
 479         kfree(card);
 480         return 0;
 481 }
 482 
 483 /**
 484  * snd_card_free_when_closed - Disconnect the card, free it later eventually
 485  * @card: soundcard structure
 486  *
 487  * Unlike snd_card_free(), this function doesn't try to release the card
 488  * resource immediately, but tries to disconnect at first.  When the card
 489  * is still in use, the function returns before freeing the resources.
 490  * The card resources will be freed when the refcount gets to zero.
 491  */
 492 int snd_card_free_when_closed(struct snd_card *card)
 493 {
 494         int ret = snd_card_disconnect(card);
 495         if (ret)
 496                 return ret;
 497         put_device(&card->card_dev);
 498         return 0;
 499 }
 500 EXPORT_SYMBOL(snd_card_free_when_closed);
 501 
 502 /**
 503  * snd_card_free - frees given soundcard structure
 504  * @card: soundcard structure
 505  *
 506  * This function releases the soundcard structure and the all assigned
 507  * devices automatically.  That is, you don't have to release the devices
 508  * by yourself.
 509  *
 510  * This function waits until the all resources are properly released.
 511  *
 512  * Return: Zero. Frees all associated devices and frees the control
 513  * interface associated to given soundcard.
 514  */
 515 int snd_card_free(struct snd_card *card)
 516 {
 517         struct completion released;
 518         int ret;
 519 
 520         init_completion(&released);
 521         card->release_completion = &released;
 522         ret = snd_card_free_when_closed(card);
 523         if (ret)
 524                 return ret;
 525         /* wait, until all devices are ready for the free operation */
 526         wait_for_completion(&released);
 527         return 0;
 528 }
 529 EXPORT_SYMBOL(snd_card_free);
 530 
 531 /* retrieve the last word of shortname or longname */
 532 static const char *retrieve_id_from_card_name(const char *name)
 533 {
 534         const char *spos = name;
 535 
 536         while (*name) {
 537                 if (isspace(*name) && isalnum(name[1]))
 538                         spos = name + 1;
 539                 name++;
 540         }
 541         return spos;
 542 }
 543 
 544 /* return true if the given id string doesn't conflict any other card ids */
 545 static bool card_id_ok(struct snd_card *card, const char *id)
 546 {
 547         int i;
 548         if (!snd_info_check_reserved_words(id))
 549                 return false;
 550         for (i = 0; i < snd_ecards_limit; i++) {
 551                 if (snd_cards[i] && snd_cards[i] != card &&
 552                     !strcmp(snd_cards[i]->id, id))
 553                         return false;
 554         }
 555         return true;
 556 }
 557 
 558 /* copy to card->id only with valid letters from nid */
 559 static void copy_valid_id_string(struct snd_card *card, const char *src,
 560                                  const char *nid)
 561 {
 562         char *id = card->id;
 563 
 564         while (*nid && !isalnum(*nid))
 565                 nid++;
 566         if (isdigit(*nid))
 567                 *id++ = isalpha(*src) ? *src : 'D';
 568         while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 569                 if (isalnum(*nid))
 570                         *id++ = *nid;
 571                 nid++;
 572         }
 573         *id = 0;
 574 }
 575 
 576 /* Set card->id from the given string
 577  * If the string conflicts with other ids, add a suffix to make it unique.
 578  */
 579 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
 580                                     const char *nid)
 581 {
 582         int len, loops;
 583         bool is_default = false;
 584         char *id;
 585         
 586         copy_valid_id_string(card, src, nid);
 587         id = card->id;
 588 
 589  again:
 590         /* use "Default" for obviously invalid strings
 591          * ("card" conflicts with proc directories)
 592          */
 593         if (!*id || !strncmp(id, "card", 4)) {
 594                 strcpy(id, "Default");
 595                 is_default = true;
 596         }
 597 
 598         len = strlen(id);
 599         for (loops = 0; loops < SNDRV_CARDS; loops++) {
 600                 char *spos;
 601                 char sfxstr[5]; /* "_012" */
 602                 int sfxlen;
 603 
 604                 if (card_id_ok(card, id))
 605                         return; /* OK */
 606 
 607                 /* Add _XYZ suffix */
 608                 sprintf(sfxstr, "_%X", loops + 1);
 609                 sfxlen = strlen(sfxstr);
 610                 if (len + sfxlen >= sizeof(card->id))
 611                         spos = id + sizeof(card->id) - sfxlen - 1;
 612                 else
 613                         spos = id + len;
 614                 strcpy(spos, sfxstr);
 615         }
 616         /* fallback to the default id */
 617         if (!is_default) {
 618                 *id = 0;
 619                 goto again;
 620         }
 621         /* last resort... */
 622         dev_err(card->dev, "unable to set card id (%s)\n", id);
 623         if (card->proc_root->name)
 624                 strlcpy(card->id, card->proc_root->name, sizeof(card->id));
 625 }
 626 
 627 /**
 628  *  snd_card_set_id - set card identification name
 629  *  @card: soundcard structure
 630  *  @nid: new identification string
 631  *
 632  *  This function sets the card identification and checks for name
 633  *  collisions.
 634  */
 635 void snd_card_set_id(struct snd_card *card, const char *nid)
 636 {
 637         /* check if user specified own card->id */
 638         if (card->id[0] != '\0')
 639                 return;
 640         mutex_lock(&snd_card_mutex);
 641         snd_card_set_id_no_lock(card, nid, nid);
 642         mutex_unlock(&snd_card_mutex);
 643 }
 644 EXPORT_SYMBOL(snd_card_set_id);
 645 
 646 static ssize_t
 647 card_id_show_attr(struct device *dev,
 648                   struct device_attribute *attr, char *buf)
 649 {
 650         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
 651         return scnprintf(buf, PAGE_SIZE, "%s\n", card->id);
 652 }
 653 
 654 static ssize_t
 655 card_id_store_attr(struct device *dev, struct device_attribute *attr,
 656                    const char *buf, size_t count)
 657 {
 658         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
 659         char buf1[sizeof(card->id)];
 660         size_t copy = count > sizeof(card->id) - 1 ?
 661                                         sizeof(card->id) - 1 : count;
 662         size_t idx;
 663         int c;
 664 
 665         for (idx = 0; idx < copy; idx++) {
 666                 c = buf[idx];
 667                 if (!isalnum(c) && c != '_' && c != '-')
 668                         return -EINVAL;
 669         }
 670         memcpy(buf1, buf, copy);
 671         buf1[copy] = '\0';
 672         mutex_lock(&snd_card_mutex);
 673         if (!card_id_ok(NULL, buf1)) {
 674                 mutex_unlock(&snd_card_mutex);
 675                 return -EEXIST;
 676         }
 677         strcpy(card->id, buf1);
 678         snd_info_card_id_change(card);
 679         mutex_unlock(&snd_card_mutex);
 680 
 681         return count;
 682 }
 683 
 684 static DEVICE_ATTR(id, 0644, card_id_show_attr, card_id_store_attr);
 685 
 686 static ssize_t
 687 card_number_show_attr(struct device *dev,
 688                      struct device_attribute *attr, char *buf)
 689 {
 690         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
 691         return scnprintf(buf, PAGE_SIZE, "%i\n", card->number);
 692 }
 693 
 694 static DEVICE_ATTR(number, 0444, card_number_show_attr, NULL);
 695 
 696 static struct attribute *card_dev_attrs[] = {
 697         &dev_attr_id.attr,
 698         &dev_attr_number.attr,
 699         NULL
 700 };
 701 
 702 static const struct attribute_group card_dev_attr_group = {
 703         .attrs  = card_dev_attrs,
 704 };
 705 
 706 /**
 707  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
 708  * @card: card instance
 709  * @group: attribute group to append
 710  */
 711 int snd_card_add_dev_attr(struct snd_card *card,
 712                           const struct attribute_group *group)
 713 {
 714         int i;
 715 
 716         /* loop for (arraysize-1) here to keep NULL at the last entry */
 717         for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
 718                 if (!card->dev_groups[i]) {
 719                         card->dev_groups[i] = group;
 720                         return 0;
 721                 }
 722         }
 723 
 724         dev_err(card->dev, "Too many groups assigned\n");
 725         return -ENOSPC;
 726 }
 727 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
 728 
 729 /**
 730  *  snd_card_register - register the soundcard
 731  *  @card: soundcard structure
 732  *
 733  *  This function registers all the devices assigned to the soundcard.
 734  *  Until calling this, the ALSA control interface is blocked from the
 735  *  external accesses.  Thus, you should call this function at the end
 736  *  of the initialization of the card.
 737  *
 738  *  Return: Zero otherwise a negative error code if the registration failed.
 739  */
 740 int snd_card_register(struct snd_card *card)
 741 {
 742         int err;
 743 
 744         if (snd_BUG_ON(!card))
 745                 return -EINVAL;
 746 
 747         if (!card->registered) {
 748                 err = device_add(&card->card_dev);
 749                 if (err < 0)
 750                         return err;
 751                 card->registered = true;
 752         }
 753 
 754         if ((err = snd_device_register_all(card)) < 0)
 755                 return err;
 756         mutex_lock(&snd_card_mutex);
 757         if (snd_cards[card->number]) {
 758                 /* already registered */
 759                 mutex_unlock(&snd_card_mutex);
 760                 return snd_info_card_register(card); /* register pending info */
 761         }
 762         if (*card->id) {
 763                 /* make a unique id name from the given string */
 764                 char tmpid[sizeof(card->id)];
 765                 memcpy(tmpid, card->id, sizeof(card->id));
 766                 snd_card_set_id_no_lock(card, tmpid, tmpid);
 767         } else {
 768                 /* create an id from either shortname or longname */
 769                 const char *src;
 770                 src = *card->shortname ? card->shortname : card->longname;
 771                 snd_card_set_id_no_lock(card, src,
 772                                         retrieve_id_from_card_name(src));
 773         }
 774         snd_cards[card->number] = card;
 775         mutex_unlock(&snd_card_mutex);
 776         err = snd_info_card_register(card);
 777         if (err < 0)
 778                 return err;
 779 
 780 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 781         if (snd_mixer_oss_notify_callback)
 782                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 783 #endif
 784         return 0;
 785 }
 786 EXPORT_SYMBOL(snd_card_register);
 787 
 788 #ifdef CONFIG_SND_PROC_FS
 789 static void snd_card_info_read(struct snd_info_entry *entry,
 790                                struct snd_info_buffer *buffer)
 791 {
 792         int idx, count;
 793         struct snd_card *card;
 794 
 795         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 796                 mutex_lock(&snd_card_mutex);
 797                 if ((card = snd_cards[idx]) != NULL) {
 798                         count++;
 799                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 800                                         idx,
 801                                         card->id,
 802                                         card->driver,
 803                                         card->shortname);
 804                         snd_iprintf(buffer, "                      %s\n",
 805                                         card->longname);
 806                 }
 807                 mutex_unlock(&snd_card_mutex);
 808         }
 809         if (!count)
 810                 snd_iprintf(buffer, "--- no soundcards ---\n");
 811 }
 812 
 813 #ifdef CONFIG_SND_OSSEMUL
 814 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 815 {
 816         int idx, count;
 817         struct snd_card *card;
 818 
 819         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 820                 mutex_lock(&snd_card_mutex);
 821                 if ((card = snd_cards[idx]) != NULL) {
 822                         count++;
 823                         snd_iprintf(buffer, "%s\n", card->longname);
 824                 }
 825                 mutex_unlock(&snd_card_mutex);
 826         }
 827         if (!count) {
 828                 snd_iprintf(buffer, "--- no soundcards ---\n");
 829         }
 830 }
 831 
 832 #endif
 833 
 834 #ifdef MODULE
 835 static void snd_card_module_info_read(struct snd_info_entry *entry,
 836                                       struct snd_info_buffer *buffer)
 837 {
 838         int idx;
 839         struct snd_card *card;
 840 
 841         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 842                 mutex_lock(&snd_card_mutex);
 843                 if ((card = snd_cards[idx]) != NULL)
 844                         snd_iprintf(buffer, "%2i %s\n",
 845                                     idx, card->module->name);
 846                 mutex_unlock(&snd_card_mutex);
 847         }
 848 }
 849 #endif
 850 
 851 int __init snd_card_info_init(void)
 852 {
 853         struct snd_info_entry *entry;
 854 
 855         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 856         if (! entry)
 857                 return -ENOMEM;
 858         entry->c.text.read = snd_card_info_read;
 859         if (snd_info_register(entry) < 0)
 860                 return -ENOMEM; /* freed in error path */
 861 
 862 #ifdef MODULE
 863         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 864         if (!entry)
 865                 return -ENOMEM;
 866         entry->c.text.read = snd_card_module_info_read;
 867         if (snd_info_register(entry) < 0)
 868                 return -ENOMEM; /* freed in error path */
 869 #endif
 870 
 871         return 0;
 872 }
 873 #endif /* CONFIG_SND_PROC_FS */
 874 
 875 /**
 876  *  snd_component_add - add a component string
 877  *  @card: soundcard structure
 878  *  @component: the component id string
 879  *
 880  *  This function adds the component id string to the supported list.
 881  *  The component can be referred from the alsa-lib.
 882  *
 883  *  Return: Zero otherwise a negative error code.
 884  */
 885   
 886 int snd_component_add(struct snd_card *card, const char *component)
 887 {
 888         char *ptr;
 889         int len = strlen(component);
 890 
 891         ptr = strstr(card->components, component);
 892         if (ptr != NULL) {
 893                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 894                         return 1;
 895         }
 896         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 897                 snd_BUG();
 898                 return -ENOMEM;
 899         }
 900         if (card->components[0] != '\0')
 901                 strcat(card->components, " ");
 902         strcat(card->components, component);
 903         return 0;
 904 }
 905 EXPORT_SYMBOL(snd_component_add);
 906 
 907 /**
 908  *  snd_card_file_add - add the file to the file list of the card
 909  *  @card: soundcard structure
 910  *  @file: file pointer
 911  *
 912  *  This function adds the file to the file linked-list of the card.
 913  *  This linked-list is used to keep tracking the connection state,
 914  *  and to avoid the release of busy resources by hotplug.
 915  *
 916  *  Return: zero or a negative error code.
 917  */
 918 int snd_card_file_add(struct snd_card *card, struct file *file)
 919 {
 920         struct snd_monitor_file *mfile;
 921 
 922         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 923         if (mfile == NULL)
 924                 return -ENOMEM;
 925         mfile->file = file;
 926         mfile->disconnected_f_op = NULL;
 927         INIT_LIST_HEAD(&mfile->shutdown_list);
 928         spin_lock(&card->files_lock);
 929         if (card->shutdown) {
 930                 spin_unlock(&card->files_lock);
 931                 kfree(mfile);
 932                 return -ENODEV;
 933         }
 934         list_add(&mfile->list, &card->files_list);
 935         get_device(&card->card_dev);
 936         spin_unlock(&card->files_lock);
 937         return 0;
 938 }
 939 EXPORT_SYMBOL(snd_card_file_add);
 940 
 941 /**
 942  *  snd_card_file_remove - remove the file from the file list
 943  *  @card: soundcard structure
 944  *  @file: file pointer
 945  *
 946  *  This function removes the file formerly added to the card via
 947  *  snd_card_file_add() function.
 948  *  If all files are removed and snd_card_free_when_closed() was
 949  *  called beforehand, it processes the pending release of
 950  *  resources.
 951  *
 952  *  Return: Zero or a negative error code.
 953  */
 954 int snd_card_file_remove(struct snd_card *card, struct file *file)
 955 {
 956         struct snd_monitor_file *mfile, *found = NULL;
 957 
 958         spin_lock(&card->files_lock);
 959         list_for_each_entry(mfile, &card->files_list, list) {
 960                 if (mfile->file == file) {
 961                         list_del(&mfile->list);
 962                         spin_lock(&shutdown_lock);
 963                         list_del(&mfile->shutdown_list);
 964                         spin_unlock(&shutdown_lock);
 965                         if (mfile->disconnected_f_op)
 966                                 fops_put(mfile->disconnected_f_op);
 967                         found = mfile;
 968                         break;
 969                 }
 970         }
 971         if (list_empty(&card->files_list))
 972                 wake_up_all(&card->remove_sleep);
 973         spin_unlock(&card->files_lock);
 974         if (!found) {
 975                 dev_err(card->dev, "card file remove problem (%p)\n", file);
 976                 return -ENOENT;
 977         }
 978         kfree(found);
 979         put_device(&card->card_dev);
 980         return 0;
 981 }
 982 EXPORT_SYMBOL(snd_card_file_remove);
 983 
 984 #ifdef CONFIG_PM
 985 /**
 986  *  snd_power_wait - wait until the power-state is changed.
 987  *  @card: soundcard structure
 988  *  @power_state: expected power state
 989  *
 990  *  Waits until the power-state is changed.
 991  *
 992  *  Return: Zero if successful, or a negative error code.
 993  */
 994 int snd_power_wait(struct snd_card *card, unsigned int power_state)
 995 {
 996         wait_queue_entry_t wait;
 997         int result = 0;
 998 
 999         /* fastpath */
1000         if (snd_power_get_state(card) == power_state)
1001                 return 0;
1002         init_waitqueue_entry(&wait, current);
1003         add_wait_queue(&card->power_sleep, &wait);
1004         while (1) {
1005                 if (card->shutdown) {
1006                         result = -ENODEV;
1007                         break;
1008                 }
1009                 if (snd_power_get_state(card) == power_state)
1010                         break;
1011                 set_current_state(TASK_UNINTERRUPTIBLE);
1012                 schedule_timeout(30 * HZ);
1013         }
1014         remove_wait_queue(&card->power_sleep, &wait);
1015         return result;
1016 }
1017 EXPORT_SYMBOL(snd_power_wait);
1018 #endif /* CONFIG_PM */
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root/sound/core/init.c

DEFINITIONS
