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