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 = NULL;
  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 static int snd_seq_device_dev_unregister(struct snd_device *device);
  94
  95 static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
  96 static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
  97 static struct ops_list *find_driver(char *id, int create_if_empty);
  98 static struct ops_list *create_driver(char *id);
  99 static void unlock_driver(struct ops_list *ops);
 100 static void remove_drivers(void);
 101
 102 /*
 103  * show all drivers and their status
 104  */
 105
 106 #ifdef CONFIG_PROC_FS
 107 static void snd_seq_device_info(struct snd_info_entry *entry,
 108                                 struct snd_info_buffer *buffer)
 109 {
 110         struct list_head *head;
 111
 112         mutex_lock(&ops_mutex);
 113         list_for_each(head, &opslist) {
 114                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 115                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 116                                 ops->id,
 117                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 118                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 119                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 120                                 ops->num_devices);
 121         }
 122         mutex_unlock(&ops_mutex);
 123 }
 124 #endif
 125
 126 /*
 127  * load all registered drivers (called from seq_clientmgr.c)
 128  */
 129
 130 #ifdef CONFIG_KMOD
 131 /* avoid auto-loading during module_init() */
 132 static int snd_seq_in_init;
 133 void snd_seq_autoload_lock(void)
 134 {
 135         snd_seq_in_init++;
 136 }
 137
 138 void snd_seq_autoload_unlock(void)
 139 {
 140         snd_seq_in_init--;
 141 }
 142 #endif
 143
 144 void snd_seq_device_load_drivers(void)
 145 {
 146 #ifdef CONFIG_KMOD
 147         struct list_head *head;
 148
 149         /* Calling request_module during module_init()
 150          * may cause blocking.
 151          */
 152         if (snd_seq_in_init)
 153                 return;
 154
 155         if (! current->fs->root)
 156                 return;
 157
 158         mutex_lock(&ops_mutex);
 159         list_for_each(head, &opslist) {
 160                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 161                 if (! (ops->driver & DRIVER_LOADED) &&
 162                     ! (ops->driver & DRIVER_REQUESTED)) {
 163                         ops->used++;
 164                         mutex_unlock(&ops_mutex);
 165                         ops->driver |= DRIVER_REQUESTED;
 166                         request_module("snd-%s", ops->id);
 167                         mutex_lock(&ops_mutex);
 168                         ops->used--;
 169                 }
 170         }
 171         mutex_unlock(&ops_mutex);
 172 #endif
 173 }
 174
 175 /*
 176  * register a sequencer device
 177  * card = card info (NULL allowed)
 178  * device = device number (if any)
 179  * id = id of driver
 180  * result = return pointer (NULL allowed if unnecessary)
 181  */
 182 int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
 183                        struct snd_seq_device **result)
 184 {
 185         struct snd_seq_device *dev;
 186         struct ops_list *ops;
 187         int err;
 188         static struct snd_device_ops dops = {
 189                 .dev_free = snd_seq_device_dev_free,
 190                 .dev_register = snd_seq_device_dev_register,
 191                 .dev_disconnect = snd_seq_device_dev_disconnect,
 192                 .dev_unregister = snd_seq_device_dev_unregister
 193         };
 194
 195         if (result)
 196                 *result = NULL;
 197
 198         snd_assert(id != NULL, return -EINVAL);
 199
 200         ops = find_driver(id, 1);
 201         if (ops == NULL)
 202                 return -ENOMEM;
 203
 204         dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
 205         if (dev == NULL) {
 206                 unlock_driver(ops);
 207                 return -ENOMEM;
 208         }
 209
 210         /* set up device info */
 211         dev->card = card;
 212         dev->device = device;
 213         strlcpy(dev->id, id, sizeof(dev->id));
 214         dev->argsize = argsize;
 215         dev->status = SNDRV_SEQ_DEVICE_FREE;
 216
 217         /* add this device to the list */
 218         mutex_lock(&ops->reg_mutex);
 219         list_add_tail(&dev->list, &ops->dev_list);
 220         ops->num_devices++;
 221         mutex_unlock(&ops->reg_mutex);
 222
 223         unlock_driver(ops);
 224
 225         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 226                 snd_seq_device_free(dev);
 227                 return err;
 228         }
 229
 230         if (result)
 231                 *result = dev;
 232
 233         return 0;
 234 }
 235
 236 /*
 237  * free the existing device
 238  */
 239 static int snd_seq_device_free(struct snd_seq_device *dev)
 240 {
 241         struct ops_list *ops;
 242
 243         snd_assert(dev != NULL, return -EINVAL);
 244
 245         ops = find_driver(dev->id, 0);
 246         if (ops == NULL)
 247                 return -ENXIO;
 248
 249         /* remove the device from the list */
 250         mutex_lock(&ops->reg_mutex);
 251         list_del(&dev->list);
 252         ops->num_devices--;
 253         mutex_unlock(&ops->reg_mutex);
 254
 255         free_device(dev, ops);
 256         if (dev->private_free)
 257                 dev->private_free(dev);
 258         kfree(dev);
 259
 260         unlock_driver(ops);
 261
 262         return 0;
 263 }
 264
 265 static int snd_seq_device_dev_free(struct snd_device *device)
 266 {
 267         struct snd_seq_device *dev = device->device_data;
 268         return snd_seq_device_free(dev);
 269 }
 270
 271 /*
 272  * register the device
 273  */
 274 static int snd_seq_device_dev_register(struct snd_device *device)
 275 {
 276         struct snd_seq_device *dev = device->device_data;
 277         struct ops_list *ops;
 278
 279         ops = find_driver(dev->id, 0);
 280         if (ops == NULL)
 281                 return -ENOENT;
 282
 283         /* initialize this device if the corresponding driver was
 284          * already loaded
 285          */
 286         if (ops->driver & DRIVER_LOADED)
 287                 init_device(dev, ops);
 288
 289         unlock_driver(ops);
 290         return 0;
 291 }
 292
 293 /*
 294  * disconnect the device
 295  */
 296 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 297 {
 298         struct snd_seq_device *dev = device->device_data;
 299         struct ops_list *ops;
 300
 301         ops = find_driver(dev->id, 0);
 302         if (ops == NULL)
 303                 return -ENOENT;
 304
 305         free_device(dev, ops);
 306
 307         unlock_driver(ops);
 308         return 0;
 309 }
 310
 311 /*
 312  * unregister the existing device
 313  */
 314 static int snd_seq_device_dev_unregister(struct snd_device *device)
 315 {
 316         struct snd_seq_device *dev = device->device_data;
 317         return snd_seq_device_free(dev);
 318 }
 319
 320 /*
 321  * register device driver
 322  * id = driver id
 323  * entry = driver operators - duplicated to each instance
 324  */
 325 int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
 326                                    int argsize)
 327 {
 328         struct list_head *head;
 329         struct ops_list *ops;
 330
 331         if (id == NULL || entry == NULL ||
 332             entry->init_device == NULL || entry->free_device == NULL)
 333                 return -EINVAL;
 334
 335         snd_seq_autoload_lock();
 336         ops = find_driver(id, 1);
 337         if (ops == NULL) {
 338                 snd_seq_autoload_unlock();
 339                 return -ENOMEM;
 340         }
 341         if (ops->driver & DRIVER_LOADED) {
 342                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 343                 unlock_driver(ops);
 344                 snd_seq_autoload_unlock();
 345                 return -EBUSY;
 346         }
 347
 348         mutex_lock(&ops->reg_mutex);
 349         /* copy driver operators */
 350         ops->ops = *entry;
 351         ops->driver |= DRIVER_LOADED;
 352         ops->argsize = argsize;
 353
 354         /* initialize existing devices if necessary */
 355         list_for_each(head, &ops->dev_list) {
 356                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 357                 init_device(dev, ops);
 358         }
 359         mutex_unlock(&ops->reg_mutex);
 360
 361         unlock_driver(ops);
 362         snd_seq_autoload_unlock();
 363
 364         return 0;
 365 }
 366
 367
 368 /*
 369  * create driver record
 370  */
 371 static struct ops_list * create_driver(char *id)
 372 {
 373         struct ops_list *ops;
 374
 375         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
 376         if (ops == NULL)
 377                 return ops;
 378         memset(ops, 0, sizeof(*ops));
 379
 380         /* set up driver entry */
 381         strlcpy(ops->id, id, sizeof(ops->id));
 382         mutex_init(&ops->reg_mutex);
 383         ops->driver = DRIVER_EMPTY;
 384         INIT_LIST_HEAD(&ops->dev_list);
 385         /* lock this instance */
 386         ops->used = 1;
 387
 388         /* register driver entry */
 389         mutex_lock(&ops_mutex);
 390         list_add_tail(&ops->list, &opslist);
 391         num_ops++;
 392         mutex_unlock(&ops_mutex);
 393
 394         return ops;
 395 }
 396
 397
 398 /*
 399  * unregister the specified driver
 400  */
 401 int snd_seq_device_unregister_driver(char *id)
 402 {
 403         struct list_head *head;
 404         struct ops_list *ops;
 405
 406         ops = find_driver(id, 0);
 407         if (ops == NULL)
 408                 return -ENXIO;
 409         if (! (ops->driver & DRIVER_LOADED) ||
 410             (ops->driver & DRIVER_LOCKED)) {
 411                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
 412                            id, ops->driver);
 413                 unlock_driver(ops);
 414                 return -EBUSY;
 415         }
 416
 417         /* close and release all devices associated with this driver */
 418         mutex_lock(&ops->reg_mutex);
 419         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 420         list_for_each(head, &ops->dev_list) {
 421                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 422                 free_device(dev, ops);
 423         }
 424
 425         ops->driver = 0;
 426         if (ops->num_init_devices > 0)
 427                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
 428                            ops->num_init_devices);
 429         mutex_unlock(&ops->reg_mutex);
 430
 431         unlock_driver(ops);
 432
 433         /* remove empty driver entries */
 434         remove_drivers();
 435
 436         return 0;
 437 }
 438
 439
 440 /*
 441  * remove empty driver entries
 442  */
 443 static void remove_drivers(void)
 444 {
 445         struct list_head *head;
 446
 447         mutex_lock(&ops_mutex);
 448         head = opslist.next;
 449         while (head != &opslist) {
 450                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 451                 if (! (ops->driver & DRIVER_LOADED) &&
 452                     ops->used == 0 && ops->num_devices == 0) {
 453                         head = head->next;
 454                         list_del(&ops->list);
 455                         kfree(ops);
 456                         num_ops--;
 457                 } else
 458                         head = head->next;
 459         }
 460         mutex_unlock(&ops_mutex);
 461 }
 462
 463 /*
 464  * initialize the device - call init_device operator
 465  */
 466 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
 467 {
 468         if (! (ops->driver & DRIVER_LOADED))
 469                 return 0; /* driver is not loaded yet */
 470         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 471                 return 0; /* already initialized */
 472         if (ops->argsize != dev->argsize) {
 473                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 474                            dev->name, ops->id, ops->argsize, dev->argsize);
 475                 return -EINVAL;
 476         }
 477         if (ops->ops.init_device(dev) >= 0) {
 478                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 479                 ops->num_init_devices++;
 480         } else {
 481                 snd_printk(KERN_ERR "init_device failed: %s: %s\n",
 482                            dev->name, dev->id);
 483         }
 484
 485         return 0;
 486 }
 487
 488 /*
 489  * release the device - call free_device operator
 490  */
 491 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
 492 {
 493         int result;
 494
 495         if (! (ops->driver & DRIVER_LOADED))
 496                 return 0; /* driver is not loaded yet */
 497         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 498                 return 0; /* not registered */
 499         if (ops->argsize != dev->argsize) {
 500                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 501                            dev->name, ops->id, ops->argsize, dev->argsize);
 502                 return -EINVAL;
 503         }
 504         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 505                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 506                 dev->driver_data = NULL;
 507                 ops->num_init_devices--;
 508         } else {
 509                 snd_printk(KERN_ERR "free_device failed: %s: %s\n",
 510                            dev->name, dev->id);
 511         }
 512
 513         return 0;
 514 }
 515
 516 /*
 517  * find the matching driver with given id
 518  */
 519 static struct ops_list * find_driver(char *id, int create_if_empty)
 520 {
 521         struct list_head *head;
 522
 523         mutex_lock(&ops_mutex);
 524         list_for_each(head, &opslist) {
 525                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 526                 if (strcmp(ops->id, id) == 0) {
 527                         ops->used++;
 528                         mutex_unlock(&ops_mutex);
 529                         return ops;
 530                 }
 531         }
 532         mutex_unlock(&ops_mutex);
 533         if (create_if_empty)
 534                 return create_driver(id);
 535         return NULL;
 536 }
 537
 538 static void unlock_driver(struct ops_list *ops)
 539 {
 540         mutex_lock(&ops_mutex);
 541         ops->used--;
 542         mutex_unlock(&ops_mutex);
 543 }
 544
 545
 546 /*
 547  * module part
 548  */
 549
 550 static int __init alsa_seq_device_init(void)
 551 {
 552 #ifdef CONFIG_PROC_FS
 553         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 554                                                   snd_seq_root);
 555         if (info_entry == NULL)
 556                 return -ENOMEM;
 557         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 558         info_entry->c.text.read_size = 2048;
 559         info_entry->c.text.read = snd_seq_device_info;
 560         if (snd_info_register(info_entry) < 0) {
 561                 snd_info_free_entry(info_entry);
 562                 return -ENOMEM;
 563         }
 564 #endif
 565         return 0;
 566 }
 567
 568 static void __exit alsa_seq_device_exit(void)
 569 {
 570         remove_drivers();
 571 #ifdef CONFIG_PROC_FS
 572         snd_info_unregister(info_entry);
 573 #endif
 574         if (num_ops)
 575                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 576 }
 577
 578 module_init(alsa_seq_device_init)
 579 module_exit(alsa_seq_device_exit)
 580
 581 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 582 EXPORT_SYMBOL(snd_seq_device_new);
 583 EXPORT_SYMBOL(snd_seq_device_register_driver);
 584 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 585 #ifdef CONFIG_KMOD
 586 EXPORT_SYMBOL(snd_seq_autoload_lock);
 587 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 588 #endif