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