sound/core/seq/seq_device.c

   1 /*
   2  *  ALSA sequencer device management
   3  *  Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation; either version 2 of the License, or
   8  *   (at your option) any later version.
   9  *
  10  *   This program is distributed in the hope that it will be useful,
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *   GNU General Public License for more details.
  14  *
  15  *   You should have received a copy of the GNU General Public License
  16  *   along with this program; if not, write to the Free Software
  17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  *
  19  *
  20  *----------------------------------------------------------------
  21  *
  22  * This device handler separates the card driver module from sequencer
  23  * stuff (sequencer core, synth drivers, etc), so that user can avoid
  24  * to spend unnecessary resources e.g. if he needs only listening to
  25  * MP3s.
  26  *
  27  * The card (or lowlevel) driver creates a sequencer device entry
  28  * via snd_seq_device_new().  This is an entry pointer to communicate
  29  * with the sequencer device "driver", which is involved with the
  30  * actual part to communicate with the sequencer core.
  31  * Each sequencer device entry has an id string and the corresponding
  32  * driver with the same id is loaded when required.  For example,
  33  * lowlevel codes to access emu8000 chip on sbawe card are included in
  34  * emu8000-synth module.  To activate this module, the hardware
  35  * resources like i/o port are passed via snd_seq_device argument.
  36  *
  37  */
  38
  39 #include <linux/init.h>
  40 #include <linux/module.h>
  41 #include <sound/core.h>
  42 #include <sound/info.h>
  43 #include <sound/seq_device.h>
  44 #include <sound/seq_kernel.h>
  45 #include <sound/initval.h>
  46 #include <linux/kmod.h>
  47 #include <linux/slab.h>
  48 #include <linux/mutex.h>
  49
  50 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  51 MODULE_DESCRIPTION("ALSA sequencer device management");
  52 MODULE_LICENSE("GPL");
  53
  54 /* driver state */
  55 #define DRIVER_EMPTY            0
  56 #define DRIVER_LOADED           (1<<0)
  57 #define DRIVER_REQUESTED        (1<<1)
  58 #define DRIVER_LOCKED           (1<<2)
  59
  60 struct ops_list {
  61         char id[ID_LEN];        /* driver id */
  62         int driver;             /* driver state */
  63         int used;               /* reference counter */
  64         int argsize;            /* argument size */
  65
  66         /* operators */
  67         struct snd_seq_dev_ops ops;
  68
  69         /* registered devices */
  70         struct list_head dev_list;      /* list of devices */
  71         int num_devices;        /* number of associated devices */
  72         int num_init_devices;   /* number of initialized devices */
  73         struct mutex reg_mutex;
  74
  75         struct list_head list;  /* next driver */
  76 };
  77
  78
  79 static LIST_HEAD(opslist);
  80 static int num_ops;
  81 static DEFINE_MUTEX(ops_mutex);
  82 #ifdef CONFIG_PROC_FS
  83 static struct snd_info_entry *info_entry;
  84 #endif
  85
  86 /*
  87  * prototypes
  88  */
  89 static int snd_seq_device_free(struct snd_seq_device *dev);
  90 static int snd_seq_device_dev_free(struct snd_device *device);
  91 static int snd_seq_device_dev_register(struct snd_device *device);
  92 static int snd_seq_device_dev_disconnect(struct snd_device *device);
  93
  94 static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
  95 static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
  96 static struct ops_list *find_driver(char *id, int create_if_empty);
  97 static struct ops_list *create_driver(char *id);
  98 static void unlock_driver(struct ops_list *ops);
  99 static void remove_drivers(void);
 100
 101 /*
 102  * show all drivers and their status
 103  */
 104
 105 #ifdef CONFIG_PROC_FS
 106 static void snd_seq_device_info(struct snd_info_entry *entry,
 107                                 struct snd_info_buffer *buffer)
 108 {
 109         struct ops_list *ops;
 110
 111         mutex_lock(&ops_mutex);
 112         list_for_each_entry(ops, &opslist, list) {
 113                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 114                                 ops->id,
 115                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 116                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 117                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 118                                 ops->num_devices);
 119         }
 120         mutex_unlock(&ops_mutex);
 121 }
 122 #endif
 123
 124 /*
 125  * load all registered drivers (called from seq_clientmgr.c)
 126  */
 127
 128 #ifdef CONFIG_MODULES
 129 /* avoid auto-loading during module_init() */
 130 static int snd_seq_in_init;
 131 void snd_seq_autoload_lock(void)
 132 {
 133         snd_seq_in_init++;
 134 }
 135
 136 void snd_seq_autoload_unlock(void)
 137 {
 138         snd_seq_in_init--;
 139 }
 140 #endif
 141
 142 void snd_seq_device_load_drivers(void)
 143 {
 144 #ifdef CONFIG_MODULES
 145         struct ops_list *ops;
 146
 147         /* Calling request_module during module_init()
 148          * may cause blocking.
 149          */
 150         if (snd_seq_in_init)
 151                 return;
 152
 153         mutex_lock(&ops_mutex);
 154         list_for_each_entry(ops, &opslist, list) {
 155                 if (! (ops->driver & DRIVER_LOADED) &&
 156                     ! (ops->driver & DRIVER_REQUESTED)) {
 157                         ops->used++;
 158                         mutex_unlock(&ops_mutex);
 159                         ops->driver |= DRIVER_REQUESTED;
 160                         request_module("snd-%s", ops->id);
 161                         mutex_lock(&ops_mutex);
 162                         ops->used--;
 163                 }
 164         }
 165         mutex_unlock(&ops_mutex);
 166 #endif
 167 }
 168
 169 /*
 170  * register a sequencer device
 171  * card = card info
 172  * device = device number (if any)
 173  * id = id of driver
 174  * result = return pointer (NULL allowed if unnecessary)
 175  */
 176 int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
 177                        struct snd_seq_device **result)
 178 {
 179         struct snd_seq_device *dev;
 180         struct ops_list *ops;
 181         int err;
 182         static struct snd_device_ops dops = {
 183                 .dev_free = snd_seq_device_dev_free,
 184                 .dev_register = snd_seq_device_dev_register,
 185                 .dev_disconnect = snd_seq_device_dev_disconnect,
 186         };
 187
 188         if (result)
 189                 *result = NULL;
 190
 191         if (snd_BUG_ON(!id))
 192                 return -EINVAL;
 193
 194         ops = find_driver(id, 1);
 195         if (ops == NULL)
 196                 return -ENOMEM;
 197
 198         dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
 199         if (dev == NULL) {
 200                 unlock_driver(ops);
 201                 return -ENOMEM;
 202         }
 203
 204         /* set up device info */
 205         dev->card = card;
 206         dev->device = device;
 207         strlcpy(dev->id, id, sizeof(dev->id));
 208         dev->argsize = argsize;
 209         dev->status = SNDRV_SEQ_DEVICE_FREE;
 210
 211         /* add this device to the list */
 212         mutex_lock(&ops->reg_mutex);
 213         list_add_tail(&dev->list, &ops->dev_list);
 214         ops->num_devices++;
 215         mutex_unlock(&ops->reg_mutex);
 216
 217         unlock_driver(ops);
 218
 219         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 220                 snd_seq_device_free(dev);
 221                 return err;
 222         }
 223
 224         if (result)
 225                 *result = dev;
 226
 227         return 0;
 228 }
 229
 230 /*
 231  * free the existing device
 232  */
 233 static int snd_seq_device_free(struct snd_seq_device *dev)
 234 {
 235         struct ops_list *ops;
 236
 237         if (snd_BUG_ON(!dev))
 238                 return -EINVAL;
 239
 240         ops = find_driver(dev->id, 0);
 241         if (ops == NULL)
 242                 return -ENXIO;
 243
 244         /* remove the device from the list */
 245         mutex_lock(&ops->reg_mutex);
 246         list_del(&dev->list);
 247         ops->num_devices--;
 248         mutex_unlock(&ops->reg_mutex);
 249
 250         free_device(dev, ops);
 251         if (dev->private_free)
 252                 dev->private_free(dev);
 253         kfree(dev);
 254
 255         unlock_driver(ops);
 256
 257         return 0;
 258 }
 259
 260 static int snd_seq_device_dev_free(struct snd_device *device)
 261 {
 262         struct snd_seq_device *dev = device->device_data;
 263         return snd_seq_device_free(dev);
 264 }
 265
 266 /*
 267  * register the device
 268  */
 269 static int snd_seq_device_dev_register(struct snd_device *device)
 270 {
 271         struct snd_seq_device *dev = device->device_data;
 272         struct ops_list *ops;
 273
 274         ops = find_driver(dev->id, 0);
 275         if (ops == NULL)
 276                 return -ENOENT;
 277
 278         /* initialize this device if the corresponding driver was
 279          * already loaded
 280          */
 281         if (ops->driver & DRIVER_LOADED)
 282                 init_device(dev, ops);
 283
 284         unlock_driver(ops);
 285         return 0;
 286 }
 287
 288 /*
 289  * disconnect the device
 290  */
 291 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 292 {
 293         struct snd_seq_device *dev = device->device_data;
 294         struct ops_list *ops;
 295
 296         ops = find_driver(dev->id, 0);
 297         if (ops == NULL)
 298                 return -ENOENT;
 299
 300         free_device(dev, ops);
 301
 302         unlock_driver(ops);
 303         return 0;
 304 }
 305
 306 /*
 307  * register device driver
 308  * id = driver id
 309  * entry = driver operators - duplicated to each instance
 310  */
 311 int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
 312                                    int argsize)
 313 {
 314         struct ops_list *ops;
 315         struct snd_seq_device *dev;
 316
 317         if (id == NULL || entry == NULL ||
 318             entry->init_device == NULL || entry->free_device == NULL)
 319                 return -EINVAL;
 320
 321         snd_seq_autoload_lock();
 322         ops = find_driver(id, 1);
 323         if (ops == NULL) {
 324                 snd_seq_autoload_unlock();
 325                 return -ENOMEM;
 326         }
 327         if (ops->driver & DRIVER_LOADED) {
 328                 pr_warn("ALSA: seq: driver_register: driver '%s' already exists\n", id);
 329                 unlock_driver(ops);
 330                 snd_seq_autoload_unlock();
 331                 return -EBUSY;
 332         }
 333
 334         mutex_lock(&ops->reg_mutex);
 335         /* copy driver operators */
 336         ops->ops = *entry;
 337         ops->driver |= DRIVER_LOADED;
 338         ops->argsize = argsize;
 339
 340         /* initialize existing devices if necessary */
 341         list_for_each_entry(dev, &ops->dev_list, list) {
 342                 init_device(dev, ops);
 343         }
 344         mutex_unlock(&ops->reg_mutex);
 345
 346         unlock_driver(ops);
 347         snd_seq_autoload_unlock();
 348
 349         return 0;
 350 }
 351
 352
 353 /*
 354  * create driver record
 355  */
 356 static struct ops_list * create_driver(char *id)
 357 {
 358         struct ops_list *ops;
 359
 360         ops = kzalloc(sizeof(*ops), GFP_KERNEL);
 361         if (ops == NULL)
 362                 return ops;
 363
 364         /* set up driver entry */
 365         strlcpy(ops->id, id, sizeof(ops->id));
 366         mutex_init(&ops->reg_mutex);
 367         /*
 368          * The ->reg_mutex locking rules are per-driver, so we create
 369          * separate per-driver lock classes:
 370          */
 371         lockdep_set_class(&ops->reg_mutex, (struct lock_class_key *)id);
 372
 373         ops->driver = DRIVER_EMPTY;
 374         INIT_LIST_HEAD(&ops->dev_list);
 375         /* lock this instance */
 376         ops->used = 1;
 377
 378         /* register driver entry */
 379         mutex_lock(&ops_mutex);
 380         list_add_tail(&ops->list, &opslist);
 381         num_ops++;
 382         mutex_unlock(&ops_mutex);
 383
 384         return ops;
 385 }
 386
 387
 388 /*
 389  * unregister the specified driver
 390  */
 391 int snd_seq_device_unregister_driver(char *id)
 392 {
 393         struct ops_list *ops;
 394         struct snd_seq_device *dev;
 395
 396         ops = find_driver(id, 0);
 397         if (ops == NULL)
 398                 return -ENXIO;
 399         if (! (ops->driver & DRIVER_LOADED) ||
 400             (ops->driver & DRIVER_LOCKED)) {
 401                 pr_err("ALSA: seq: driver_unregister: cannot unload driver '%s': status=%x\n",
 402                            id, ops->driver);
 403                 unlock_driver(ops);
 404                 return -EBUSY;
 405         }
 406
 407         /* close and release all devices associated with this driver */
 408         mutex_lock(&ops->reg_mutex);
 409         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 410         list_for_each_entry(dev, &ops->dev_list, list) {
 411                 free_device(dev, ops);
 412         }
 413
 414         ops->driver = 0;
 415         if (ops->num_init_devices > 0)
 416                 pr_err("ALSA: seq: free_driver: init_devices > 0!! (%d)\n",
 417                            ops->num_init_devices);
 418         mutex_unlock(&ops->reg_mutex);
 419
 420         unlock_driver(ops);
 421
 422         /* remove empty driver entries */
 423         remove_drivers();
 424
 425         return 0;
 426 }
 427
 428
 429 /*
 430  * remove empty driver entries
 431  */
 432 static void remove_drivers(void)
 433 {
 434         struct list_head *head;
 435
 436         mutex_lock(&ops_mutex);
 437         head = opslist.next;
 438         while (head != &opslist) {
 439                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 440                 if (! (ops->driver & DRIVER_LOADED) &&
 441                     ops->used == 0 && ops->num_devices == 0) {
 442                         head = head->next;
 443                         list_del(&ops->list);
 444                         kfree(ops);
 445                         num_ops--;
 446                 } else
 447                         head = head->next;
 448         }
 449         mutex_unlock(&ops_mutex);
 450 }
 451
 452 /*
 453  * initialize the device - call init_device operator
 454  */
 455 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
 456 {
 457         if (! (ops->driver & DRIVER_LOADED))
 458                 return 0; /* driver is not loaded yet */
 459         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 460                 return 0; /* already initialized */
 461         if (ops->argsize != dev->argsize) {
 462                 pr_err("ALSA: seq: incompatible device '%s' for plug-in '%s' (%d %d)\n",
 463                            dev->name, ops->id, ops->argsize, dev->argsize);
 464                 return -EINVAL;
 465         }
 466         if (ops->ops.init_device(dev) >= 0) {
 467                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 468                 ops->num_init_devices++;
 469         } else {
 470                 pr_err("ALSA: seq: init_device failed: %s: %s\n",
 471                            dev->name, dev->id);
 472         }
 473
 474         return 0;
 475 }
 476
 477 /*
 478  * release the device - call free_device operator
 479  */
 480 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
 481 {
 482         int result;
 483
 484         if (! (ops->driver & DRIVER_LOADED))
 485                 return 0; /* driver is not loaded yet */
 486         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 487                 return 0; /* not registered */
 488         if (ops->argsize != dev->argsize) {
 489                 pr_err("ALSA: seq: incompatible device '%s' for plug-in '%s' (%d %d)\n",
 490                            dev->name, ops->id, ops->argsize, dev->argsize);
 491                 return -EINVAL;
 492         }
 493         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 494                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 495                 dev->driver_data = NULL;
 496                 ops->num_init_devices--;
 497         } else {
 498                 pr_err("ALSA: seq: free_device failed: %s: %s\n",
 499                            dev->name, dev->id);
 500         }
 501
 502         return 0;
 503 }
 504
 505 /*
 506  * find the matching driver with given id
 507  */
 508 static struct ops_list * find_driver(char *id, int create_if_empty)
 509 {
 510         struct ops_list *ops;
 511
 512         mutex_lock(&ops_mutex);
 513         list_for_each_entry(ops, &opslist, list) {
 514                 if (strcmp(ops->id, id) == 0) {
 515                         ops->used++;
 516                         mutex_unlock(&ops_mutex);
 517                         return ops;
 518                 }
 519         }
 520         mutex_unlock(&ops_mutex);
 521         if (create_if_empty)
 522                 return create_driver(id);
 523         return NULL;
 524 }
 525
 526 static void unlock_driver(struct ops_list *ops)
 527 {
 528         mutex_lock(&ops_mutex);
 529         ops->used--;
 530         mutex_unlock(&ops_mutex);
 531 }
 532
 533
 534 /*
 535  * module part
 536  */
 537
 538 static int __init alsa_seq_device_init(void)
 539 {
 540 #ifdef CONFIG_PROC_FS
 541         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 542                                                   snd_seq_root);
 543         if (info_entry == NULL)
 544                 return -ENOMEM;
 545         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 546         info_entry->c.text.read = snd_seq_device_info;
 547         if (snd_info_register(info_entry) < 0) {
 548                 snd_info_free_entry(info_entry);
 549                 return -ENOMEM;
 550         }
 551 #endif
 552         return 0;
 553 }
 554
 555 static void __exit alsa_seq_device_exit(void)
 556 {
 557         remove_drivers();
 558 #ifdef CONFIG_PROC_FS
 559         snd_info_free_entry(info_entry);
 560 #endif
 561         if (num_ops)
 562                 pr_err("ALSA: seq: drivers not released (%d)\n", num_ops);
 563 }
 564
 565 module_init(alsa_seq_device_init)
 566 module_exit(alsa_seq_device_exit)
 567
 568 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 569 EXPORT_SYMBOL(snd_seq_device_new);
 570 EXPORT_SYMBOL(snd_seq_device_register_driver);
 571 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 572 #ifdef CONFIG_MODULES
 573 EXPORT_SYMBOL(snd_seq_autoload_lock);
 574 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 575 #endif