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
  49 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  50 MODULE_DESCRIPTION("ALSA sequencer device management");
  51 MODULE_LICENSE("GPL");
  52
  53 /*
  54  * driver list
  55  */
  56 typedef struct ops_list ops_list_t;
  57
  58 /* driver state */
  59 #define DRIVER_EMPTY            0
  60 #define DRIVER_LOADED           (1<<0)
  61 #define DRIVER_REQUESTED        (1<<1)
  62 #define DRIVER_LOCKED           (1<<2)
  63
  64 struct ops_list {
  65         char id[ID_LEN];        /* driver id */
  66         int driver;             /* driver state */
  67         int used;               /* reference counter */
  68         int argsize;            /* argument size */
  69
  70         /* operators */
  71         snd_seq_dev_ops_t ops;
  72
  73         /* registred devices */
  74         struct list_head dev_list;      /* list of devices */
  75         int num_devices;        /* number of associated devices */
  76         int num_init_devices;   /* number of initialized devices */
  77         struct semaphore reg_mutex;
  78
  79         struct list_head list;  /* next driver */
  80 };
  81
  82
  83 static LIST_HEAD(opslist);
  84 static int num_ops;
  85 static DECLARE_MUTEX(ops_mutex);
  86 static snd_info_entry_t *info_entry = NULL;
  87
  88 /*
  89  * prototypes
  90  */
  91 static int snd_seq_device_free(snd_seq_device_t *dev);
  92 static int snd_seq_device_dev_free(snd_device_t *device);
  93 static int snd_seq_device_dev_register(snd_device_t *device);
  94 static int snd_seq_device_dev_disconnect(snd_device_t *device);
  95 static int snd_seq_device_dev_unregister(snd_device_t *device);
  96
  97 static int init_device(snd_seq_device_t *dev, ops_list_t *ops);
  98 static int free_device(snd_seq_device_t *dev, ops_list_t *ops);
  99 static ops_list_t *find_driver(char *id, int create_if_empty);
 100 static ops_list_t *create_driver(char *id);
 101 static void unlock_driver(ops_list_t *ops);
 102 static void remove_drivers(void);
 103
 104 /*
 105  * show all drivers and their status
 106  */
 107
 108 static void snd_seq_device_info(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
 109 {
 110         struct list_head *head;
 111
 112         down(&ops_mutex);
 113         list_for_each(head, &opslist) {
 114                 ops_list_t *ops = list_entry(head, ops_list_t, 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         up(&ops_mutex);
 123 }
 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         down(&ops_mutex);
 158         list_for_each(head, &opslist) {
 159                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 160                 if (! (ops->driver & DRIVER_LOADED) &&
 161                     ! (ops->driver & DRIVER_REQUESTED)) {
 162                         ops->used++;
 163                         up(&ops_mutex);
 164                         ops->driver |= DRIVER_REQUESTED;
 165                         request_module("snd-%s", ops->id);
 166                         down(&ops_mutex);
 167                         ops->used--;
 168                 }
 169         }
 170         up(&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(snd_card_t *card, int device, char *id, int argsize,
 182                        snd_seq_device_t **result)
 183 {
 184         snd_seq_device_t *dev;
 185         ops_list_t *ops;
 186         int err;
 187         static snd_device_ops_t 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                 .dev_unregister = snd_seq_device_dev_unregister
 192         };
 193
 194         if (result)
 195                 *result = NULL;
 196
 197         snd_assert(id != NULL, return -EINVAL);
 198
 199         ops = find_driver(id, 1);
 200         if (ops == NULL)
 201                 return -ENOMEM;
 202
 203         dev = kcalloc(1, sizeof(*dev)*2 + argsize, GFP_KERNEL);
 204         if (dev == NULL) {
 205                 unlock_driver(ops);
 206                 return -ENOMEM;
 207         }
 208
 209         /* set up device info */
 210         dev->card = card;
 211         dev->device = device;
 212         strlcpy(dev->id, id, sizeof(dev->id));
 213         dev->argsize = argsize;
 214         dev->status = SNDRV_SEQ_DEVICE_FREE;
 215
 216         /* add this device to the list */
 217         down(&ops->reg_mutex);
 218         list_add_tail(&dev->list, &ops->dev_list);
 219         ops->num_devices++;
 220         up(&ops->reg_mutex);
 221
 222         unlock_driver(ops);
 223
 224         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 225                 snd_seq_device_free(dev);
 226                 return err;
 227         }
 228
 229         if (result)
 230                 *result = dev;
 231
 232         return 0;
 233 }
 234
 235 /*
 236  * free the existing device
 237  */
 238 static int snd_seq_device_free(snd_seq_device_t *dev)
 239 {
 240         ops_list_t *ops;
 241
 242         snd_assert(dev != NULL, return -EINVAL);
 243
 244         ops = find_driver(dev->id, 0);
 245         if (ops == NULL)
 246                 return -ENXIO;
 247
 248         /* remove the device from the list */
 249         down(&ops->reg_mutex);
 250         list_del(&dev->list);
 251         ops->num_devices--;
 252         up(&ops->reg_mutex);
 253
 254         free_device(dev, ops);
 255         if (dev->private_free)
 256                 dev->private_free(dev);
 257         kfree(dev);
 258
 259         unlock_driver(ops);
 260
 261         return 0;
 262 }
 263
 264 static int snd_seq_device_dev_free(snd_device_t *device)
 265 {
 266         snd_seq_device_t *dev = device->device_data;
 267         return snd_seq_device_free(dev);
 268 }
 269
 270 /*
 271  * register the device
 272  */
 273 static int snd_seq_device_dev_register(snd_device_t *device)
 274 {
 275         snd_seq_device_t *dev = device->device_data;
 276         ops_list_t *ops;
 277
 278         ops = find_driver(dev->id, 0);
 279         if (ops == NULL)
 280                 return -ENOENT;
 281
 282         /* initialize this device if the corresponding driver was
 283          * already loaded
 284          */
 285         if (ops->driver & DRIVER_LOADED)
 286                 init_device(dev, ops);
 287
 288         unlock_driver(ops);
 289         return 0;
 290 }
 291
 292 /*
 293  * disconnect the device
 294  */
 295 static int snd_seq_device_dev_disconnect(snd_device_t *device)
 296 {
 297         snd_seq_device_t *dev = device->device_data;
 298         ops_list_t *ops;
 299
 300         ops = find_driver(dev->id, 0);
 301         if (ops == NULL)
 302                 return -ENOENT;
 303
 304         free_device(dev, ops);
 305
 306         unlock_driver(ops);
 307         return 0;
 308 }
 309
 310 /*
 311  * unregister the existing device
 312  */
 313 static int snd_seq_device_dev_unregister(snd_device_t *device)
 314 {
 315         snd_seq_device_t *dev = device->device_data;
 316         return snd_seq_device_free(dev);
 317 }
 318
 319 /*
 320  * register device driver
 321  * id = driver id
 322  * entry = driver operators - duplicated to each instance
 323  */
 324 int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsize)
 325 {
 326         struct list_head *head;
 327         ops_list_t *ops;
 328
 329         if (id == NULL || entry == NULL ||
 330             entry->init_device == NULL || entry->free_device == NULL)
 331                 return -EINVAL;
 332
 333         snd_seq_autoload_lock();
 334         ops = find_driver(id, 1);
 335         if (ops == NULL) {
 336                 snd_seq_autoload_unlock();
 337                 return -ENOMEM;
 338         }
 339         if (ops->driver & DRIVER_LOADED) {
 340                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 341                 unlock_driver(ops);
 342                 snd_seq_autoload_unlock();
 343                 return -EBUSY;
 344         }
 345
 346         down(&ops->reg_mutex);
 347         /* copy driver operators */
 348         ops->ops = *entry;
 349         ops->driver |= DRIVER_LOADED;
 350         ops->argsize = argsize;
 351
 352         /* initialize existing devices if necessary */
 353         list_for_each(head, &ops->dev_list) {
 354                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
 355                 init_device(dev, ops);
 356         }
 357         up(&ops->reg_mutex);
 358
 359         unlock_driver(ops);
 360         snd_seq_autoload_unlock();
 361
 362         return 0;
 363 }
 364
 365
 366 /*
 367  * create driver record
 368  */
 369 static ops_list_t * create_driver(char *id)
 370 {
 371         ops_list_t *ops;
 372
 373         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
 374         if (ops == NULL)
 375                 return ops;
 376         memset(ops, 0, sizeof(*ops));
 377
 378         /* set up driver entry */
 379         strlcpy(ops->id, id, sizeof(ops->id));
 380         init_MUTEX(&ops->reg_mutex);
 381         ops->driver = DRIVER_EMPTY;
 382         INIT_LIST_HEAD(&ops->dev_list);
 383         /* lock this instance */
 384         ops->used = 1;
 385
 386         /* register driver entry */
 387         down(&ops_mutex);
 388         list_add_tail(&ops->list, &opslist);
 389         num_ops++;
 390         up(&ops_mutex);
 391
 392         return ops;
 393 }
 394
 395
 396 /*
 397  * unregister the specified driver
 398  */
 399 int snd_seq_device_unregister_driver(char *id)
 400 {
 401         struct list_head *head;
 402         ops_list_t *ops;
 403
 404         ops = find_driver(id, 0);
 405         if (ops == NULL)
 406                 return -ENXIO;
 407         if (! (ops->driver & DRIVER_LOADED) ||
 408             (ops->driver & DRIVER_LOCKED)) {
 409                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n", id, ops->driver);
 410                 unlock_driver(ops);
 411                 return -EBUSY;
 412         }
 413
 414         /* close and release all devices associated with this driver */
 415         down(&ops->reg_mutex);
 416         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 417         list_for_each(head, &ops->dev_list) {
 418                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
 419                 free_device(dev, ops);
 420         }
 421
 422         ops->driver = 0;
 423         if (ops->num_init_devices > 0)
 424                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n", ops->num_init_devices);
 425         up(&ops->reg_mutex);
 426
 427         unlock_driver(ops);
 428
 429         /* remove empty driver entries */
 430         remove_drivers();
 431
 432         return 0;
 433 }
 434
 435
 436 /*
 437  * remove empty driver entries
 438  */
 439 static void remove_drivers(void)
 440 {
 441         struct list_head *head;
 442
 443         down(&ops_mutex);
 444         head = opslist.next;
 445         while (head != &opslist) {
 446                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 447                 if (! (ops->driver & DRIVER_LOADED) &&
 448                     ops->used == 0 && ops->num_devices == 0) {
 449                         head = head->next;
 450                         list_del(&ops->list);
 451                         kfree(ops);
 452                         num_ops--;
 453                 } else
 454                         head = head->next;
 455         }
 456         up(&ops_mutex);
 457 }
 458
 459 /*
 460  * initialize the device - call init_device operator
 461  */
 462 static int init_device(snd_seq_device_t *dev, ops_list_t *ops)
 463 {
 464         if (! (ops->driver & DRIVER_LOADED))
 465                 return 0; /* driver is not loaded yet */
 466         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 467                 return 0; /* already initialized */
 468         if (ops->argsize != dev->argsize) {
 469                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize);
 470                 return -EINVAL;
 471         }
 472         if (ops->ops.init_device(dev) >= 0) {
 473                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 474                 ops->num_init_devices++;
 475         } else {
 476                 snd_printk(KERN_ERR "init_device failed: %s: %s\n", 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(snd_seq_device_t *dev, ops_list_t *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", dev->name, ops->id, ops->argsize, dev->argsize);
 495                 return -EINVAL;
 496         }
 497         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 498                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 499                 dev->driver_data = NULL;
 500                 ops->num_init_devices--;
 501         } else {
 502                 snd_printk(KERN_ERR "free_device failed: %s: %s\n", dev->name, dev->id);
 503         }
 504
 505         return 0;
 506 }
 507
 508 /*
 509  * find the matching driver with given id
 510  */
 511 static ops_list_t * find_driver(char *id, int create_if_empty)
 512 {
 513         struct list_head *head;
 514
 515         down(&ops_mutex);
 516         list_for_each(head, &opslist) {
 517                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 518                 if (strcmp(ops->id, id) == 0) {
 519                         ops->used++;
 520                         up(&ops_mutex);
 521                         return ops;
 522                 }
 523         }
 524         up(&ops_mutex);
 525         if (create_if_empty)
 526                 return create_driver(id);
 527         return NULL;
 528 }
 529
 530 static void unlock_driver(ops_list_t *ops)
 531 {
 532         down(&ops_mutex);
 533         ops->used--;
 534         up(&ops_mutex);
 535 }
 536
 537
 538 /*
 539  * module part
 540  */
 541
 542 static int __init alsa_seq_device_init(void)
 543 {
 544         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers", snd_seq_root);
 545         if (info_entry == NULL)
 546                 return -ENOMEM;
 547         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 548         info_entry->c.text.read_size = 2048;
 549         info_entry->c.text.read = snd_seq_device_info;
 550         if (snd_info_register(info_entry) < 0) {
 551                 snd_info_free_entry(info_entry);
 552                 return -ENOMEM;
 553         }
 554         return 0;
 555 }
 556
 557 static void __exit alsa_seq_device_exit(void)
 558 {
 559         remove_drivers();
 560         snd_info_unregister(info_entry);
 561         if (num_ops)
 562                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 563 }
 564
 565 module_init(alsa_seq_device_init)
 566 module_exit(alsa_seq_device_exit)
 567
 568 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 569 EXPORT_SYMBOL(snd_seq_device_new);
 570 EXPORT_SYMBOL(snd_seq_device_register_driver);
 571 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 572 #ifdef CONFIG_KMOD
 573 EXPORT_SYMBOL(snd_seq_autoload_lock);
 574 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 575 #endif