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 <sound/driver.h>
  40 #include <linux/init.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         /* registred 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 list_head *head;
 110
 111         mutex_lock(&ops_mutex);
 112         list_for_each(head, &opslist) {
 113                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 114                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 115                                 ops->id,
 116                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 117                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 118                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 119                                 ops->num_devices);
 120         }
 121         mutex_unlock(&ops_mutex);
 122 }
 123 #endif
 124
 125 /*
 126  * load all registered drivers (called from seq_clientmgr.c)
 127  */
 128
 129 #ifdef CONFIG_KMOD
 130 /* avoid auto-loading during module_init() */
 131 static int snd_seq_in_init;
 132 void snd_seq_autoload_lock(void)
 133 {
 134         snd_seq_in_init++;
 135 }
 136
 137 void snd_seq_autoload_unlock(void)
 138 {
 139         snd_seq_in_init--;
 140 }
 141 #endif
 142
 143 void snd_seq_device_load_drivers(void)
 144 {
 145 #ifdef CONFIG_KMOD
 146         struct list_head *head;
 147
 148         /* Calling request_module during module_init()
 149          * may cause blocking.
 150          */
 151         if (snd_seq_in_init)
 152                 return;
 153
 154         if (! current->fs->root)
 155                 return;
 156
 157         mutex_lock(&ops_mutex);
 158         list_for_each(head, &opslist) {
 159                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 160                 if (! (ops->driver & DRIVER_LOADED) &&
 161                     ! (ops->driver & DRIVER_REQUESTED)) {
 162                         ops->used++;
 163                         mutex_unlock(&ops_mutex);
 164                         ops->driver |= DRIVER_REQUESTED;
 165                         request_module("snd-%s", ops->id);
 166                         mutex_lock(&ops_mutex);
 167                         ops->used--;
 168                 }
 169         }
 170         mutex_unlock(&ops_mutex);
 171 #endif
 172 }
 173
 174 /*
 175  * register a sequencer device
 176  * card = card info (NULL allowed)
 177  * device = device number (if any)
 178  * id = id of driver
 179  * result = return pointer (NULL allowed if unnecessary)
 180  */
 181 int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
 182                        struct snd_seq_device **result)
 183 {
 184         struct snd_seq_device *dev;
 185         struct ops_list *ops;
 186         int err;
 187         static struct snd_device_ops dops = {
 188                 .dev_free = snd_seq_device_dev_free,
 189                 .dev_register = snd_seq_device_dev_register,
 190                 .dev_disconnect = snd_seq_device_dev_disconnect,
 191         };
 192
 193         if (result)
 194                 *result = NULL;
 195
 196         snd_assert(id != NULL, return -EINVAL);
 197
 198         ops = find_driver(id, 1);
 199         if (ops == NULL)
 200                 return -ENOMEM;
 201
 202         dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
 203         if (dev == NULL) {
 204                 unlock_driver(ops);
 205                 return -ENOMEM;
 206         }
 207
 208         /* set up device info */
 209         dev->card = card;
 210         dev->device = device;
 211         strlcpy(dev->id, id, sizeof(dev->id));
 212         dev->argsize = argsize;
 213         dev->status = SNDRV_SEQ_DEVICE_FREE;
 214
 215         /* add this device to the list */
 216         mutex_lock(&ops->reg_mutex);
 217         list_add_tail(&dev->list, &ops->dev_list);
 218         ops->num_devices++;
 219         mutex_unlock(&ops->reg_mutex);
 220
 221         unlock_driver(ops);
 222
 223         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 224                 snd_seq_device_free(dev);
 225                 return err;
 226         }
 227
 228         if (result)
 229                 *result = dev;
 230
 231         return 0;
 232 }
 233
 234 /*
 235  * free the existing device
 236  */
 237 static int snd_seq_device_free(struct snd_seq_device *dev)
 238 {
 239         struct ops_list *ops;
 240
 241         snd_assert(dev != NULL, return -EINVAL);
 242
 243         ops = find_driver(dev->id, 0);
 244         if (ops == NULL)
 245                 return -ENXIO;
 246
 247         /* remove the device from the list */
 248         mutex_lock(&ops->reg_mutex);
 249         list_del(&dev->list);
 250         ops->num_devices--;
 251         mutex_unlock(&ops->reg_mutex);
 252
 253         free_device(dev, ops);
 254         if (dev->private_free)
 255                 dev->private_free(dev);
 256         kfree(dev);
 257
 258         unlock_driver(ops);
 259
 260         return 0;
 261 }
 262
 263 static int snd_seq_device_dev_free(struct snd_device *device)
 264 {
 265         struct snd_seq_device *dev = device->device_data;
 266         return snd_seq_device_free(dev);
 267 }
 268
 269 /*
 270  * register the device
 271  */
 272 static int snd_seq_device_dev_register(struct snd_device *device)
 273 {
 274         struct snd_seq_device *dev = device->device_data;
 275         struct ops_list *ops;
 276
 277         ops = find_driver(dev->id, 0);
 278         if (ops == NULL)
 279                 return -ENOENT;
 280
 281         /* initialize this device if the corresponding driver was
 282          * already loaded
 283          */
 284         if (ops->driver & DRIVER_LOADED)
 285                 init_device(dev, ops);
 286
 287         unlock_driver(ops);
 288         return 0;
 289 }
 290
 291 /*
 292  * disconnect the device
 293  */
 294 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 295 {
 296         struct snd_seq_device *dev = device->device_data;
 297         struct ops_list *ops;
 298
 299         ops = find_driver(dev->id, 0);
 300         if (ops == NULL)
 301                 return -ENOENT;
 302
 303         free_device(dev, ops);
 304
 305         unlock_driver(ops);
 306         return 0;
 307 }
 308
 309 /*
 310  * register device driver
 311  * id = driver id
 312  * entry = driver operators - duplicated to each instance
 313  */
 314 int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
 315                                    int argsize)
 316 {
 317         struct list_head *head;
 318         struct ops_list *ops;
 319
 320         if (id == NULL || entry == NULL ||
 321             entry->init_device == NULL || entry->free_device == NULL)
 322                 return -EINVAL;
 323
 324         snd_seq_autoload_lock();
 325         ops = find_driver(id, 1);
 326         if (ops == NULL) {
 327                 snd_seq_autoload_unlock();
 328                 return -ENOMEM;
 329         }
 330         if (ops->driver & DRIVER_LOADED) {
 331                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 332                 unlock_driver(ops);
 333                 snd_seq_autoload_unlock();
 334                 return -EBUSY;
 335         }
 336
 337         mutex_lock(&ops->reg_mutex);
 338         /* copy driver operators */
 339         ops->ops = *entry;
 340         ops->driver |= DRIVER_LOADED;
 341         ops->argsize = argsize;
 342
 343         /* initialize existing devices if necessary */
 344         list_for_each(head, &ops->dev_list) {
 345                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 346                 init_device(dev, ops);
 347         }
 348         mutex_unlock(&ops->reg_mutex);
 349
 350         unlock_driver(ops);
 351         snd_seq_autoload_unlock();
 352
 353         return 0;
 354 }
 355
 356
 357 /*
 358  * create driver record
 359  */
 360 static struct ops_list * create_driver(char *id)
 361 {
 362         struct ops_list *ops;
 363
 364         ops = kzalloc(sizeof(*ops), GFP_KERNEL);
 365         if (ops == NULL)
 366                 return ops;
 367
 368         /* set up driver entry */
 369         strlcpy(ops->id, id, sizeof(ops->id));
 370         mutex_init(&ops->reg_mutex);
 371         /*
 372          * The ->reg_mutex locking rules are per-driver, so we create
 373          * separate per-driver lock classes:
 374          */
 375         lockdep_set_class(&ops->reg_mutex, (struct lock_class_key *)id);
 376
 377         ops->driver = DRIVER_EMPTY;
 378         INIT_LIST_HEAD(&ops->dev_list);
 379         /* lock this instance */
 380         ops->used = 1;
 381
 382         /* register driver entry */
 383         mutex_lock(&ops_mutex);
 384         list_add_tail(&ops->list, &opslist);
 385         num_ops++;
 386         mutex_unlock(&ops_mutex);
 387
 388         return ops;
 389 }
 390
 391
 392 /*
 393  * unregister the specified driver
 394  */
 395 int snd_seq_device_unregister_driver(char *id)
 396 {
 397         struct list_head *head;
 398         struct ops_list *ops;
 399
 400         ops = find_driver(id, 0);
 401         if (ops == NULL)
 402                 return -ENXIO;
 403         if (! (ops->driver & DRIVER_LOADED) ||
 404             (ops->driver & DRIVER_LOCKED)) {
 405                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
 406                            id, ops->driver);
 407                 unlock_driver(ops);
 408                 return -EBUSY;
 409         }
 410
 411         /* close and release all devices associated with this driver */
 412         mutex_lock(&ops->reg_mutex);
 413         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 414         list_for_each(head, &ops->dev_list) {
 415                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 416                 free_device(dev, ops);
 417         }
 418
 419         ops->driver = 0;
 420         if (ops->num_init_devices > 0)
 421                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
 422                            ops->num_init_devices);
 423         mutex_unlock(&ops->reg_mutex);
 424
 425         unlock_driver(ops);
 426
 427         /* remove empty driver entries */
 428         remove_drivers();
 429
 430         return 0;
 431 }
 432
 433
 434 /*
 435  * remove empty driver entries
 436  */
 437 static void remove_drivers(void)
 438 {
 439         struct list_head *head;
 440
 441         mutex_lock(&ops_mutex);
 442         head = opslist.next;
 443         while (head != &opslist) {
 444                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 445                 if (! (ops->driver & DRIVER_LOADED) &&
 446                     ops->used == 0 && ops->num_devices == 0) {
 447                         head = head->next;
 448                         list_del(&ops->list);
 449                         kfree(ops);
 450                         num_ops--;
 451                 } else
 452                         head = head->next;
 453         }
 454         mutex_unlock(&ops_mutex);
 455 }
 456
 457 /*
 458  * initialize the device - call init_device operator
 459  */
 460 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
 461 {
 462         if (! (ops->driver & DRIVER_LOADED))
 463                 return 0; /* driver is not loaded yet */
 464         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 465                 return 0; /* already initialized */
 466         if (ops->argsize != dev->argsize) {
 467                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 468                            dev->name, ops->id, ops->argsize, dev->argsize);
 469                 return -EINVAL;
 470         }
 471         if (ops->ops.init_device(dev) >= 0) {
 472                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 473                 ops->num_init_devices++;
 474         } else {
 475                 snd_printk(KERN_ERR "init_device failed: %s: %s\n",
 476                            dev->name, dev->id);
 477         }
 478
 479         return 0;
 480 }
 481
 482 /*
 483  * release the device - call free_device operator
 484  */
 485 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
 486 {
 487         int result;
 488
 489         if (! (ops->driver & DRIVER_LOADED))
 490                 return 0; /* driver is not loaded yet */
 491         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 492                 return 0; /* not registered */
 493         if (ops->argsize != dev->argsize) {
 494                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 495                            dev->name, ops->id, ops->argsize, dev->argsize);
 496                 return -EINVAL;
 497         }
 498         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 499                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 500                 dev->driver_data = NULL;
 501                 ops->num_init_devices--;
 502         } else {
 503                 snd_printk(KERN_ERR "free_device failed: %s: %s\n",
 504                            dev->name, dev->id);
 505         }
 506
 507         return 0;
 508 }
 509
 510 /*
 511  * find the matching driver with given id
 512  */
 513 static struct ops_list * find_driver(char *id, int create_if_empty)
 514 {
 515         struct list_head *head;
 516
 517         mutex_lock(&ops_mutex);
 518         list_for_each(head, &opslist) {
 519                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 520                 if (strcmp(ops->id, id) == 0) {
 521                         ops->used++;
 522                         mutex_unlock(&ops_mutex);
 523                         return ops;
 524                 }
 525         }
 526         mutex_unlock(&ops_mutex);
 527         if (create_if_empty)
 528                 return create_driver(id);
 529         return NULL;
 530 }
 531
 532 static void unlock_driver(struct ops_list *ops)
 533 {
 534         mutex_lock(&ops_mutex);
 535         ops->used--;
 536         mutex_unlock(&ops_mutex);
 537 }
 538
 539
 540 /*
 541  * module part
 542  */
 543
 544 static int __init alsa_seq_device_init(void)
 545 {
 546 #ifdef CONFIG_PROC_FS
 547         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 548                                                   snd_seq_root);
 549         if (info_entry == NULL)
 550                 return -ENOMEM;
 551         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 552         info_entry->c.text.read = snd_seq_device_info;
 553         if (snd_info_register(info_entry) < 0) {
 554                 snd_info_free_entry(info_entry);
 555                 return -ENOMEM;
 556         }
 557 #endif
 558         return 0;
 559 }
 560
 561 static void __exit alsa_seq_device_exit(void)
 562 {
 563         remove_drivers();
 564 #ifdef CONFIG_PROC_FS
 565         snd_info_free_entry(info_entry);
 566 #endif
 567         if (num_ops)
 568                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 569 }
 570
 571 module_init(alsa_seq_device_init)
 572 module_exit(alsa_seq_device_exit)
 573
 574 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 575 EXPORT_SYMBOL(snd_seq_device_new);
 576 EXPORT_SYMBOL(snd_seq_device_register_driver);
 577 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 578 #ifdef CONFIG_KMOD
 579 EXPORT_SYMBOL(snd_seq_autoload_lock);
 580 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 581 #endif