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