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/initval.h>
  45 #include <linux/kmod.h>
  46 #include <linux/slab.h>
  47
  48 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  49 MODULE_DESCRIPTION("ALSA sequencer device management");
  50 MODULE_LICENSE("GPL");
  51 MODULE_CLASSES("{sound}");
  52 MODULE_SUPPORTED_DEVICE("sound");
  53
  54 /*
  55  * driver list
  56  */
  57 typedef struct ops_list ops_list_t;
  58
  59 /* driver state */
  60 #define DRIVER_EMPTY            0
  61 #define DRIVER_LOADED           (1<<0)
  62 #define DRIVER_REQUESTED        (1<<1)
  63 #define DRIVER_LOCKED           (1<<2)
  64
  65 struct ops_list {
  66         char id[ID_LEN];        /* driver id */
  67         int driver;             /* driver state */
  68         int used;               /* reference counter */
  69         int argsize;            /* argument size */
  70
  71         /* operators */
  72         snd_seq_dev_ops_t ops;
  73
  74         /* registred devices */
  75         struct list_head dev_list;      /* list of devices */
  76         int num_devices;        /* number of associated devices */
  77         int num_init_devices;   /* number of initialized devices */
  78         struct semaphore reg_mutex;
  79
  80         struct list_head list;  /* next driver */
  81 };
  82
  83
  84 static LIST_HEAD(opslist);
  85 static int num_ops;
  86 static DECLARE_MUTEX(ops_mutex);
  87 static snd_info_entry_t *info_entry = NULL;
  88
  89 /*
  90  * prototypes
  91  */
  92 static int snd_seq_device_free(snd_seq_device_t *dev);
  93 static int snd_seq_device_dev_free(snd_device_t *device);
  94 static int snd_seq_device_dev_register(snd_device_t *device);
  95 static int snd_seq_device_dev_disconnect(snd_device_t *device);
  96 static int snd_seq_device_dev_unregister(snd_device_t *device);
  97
  98 static int init_device(snd_seq_device_t *dev, ops_list_t *ops);
  99 static int free_device(snd_seq_device_t *dev, ops_list_t *ops);
 100 static ops_list_t *find_driver(char *id, int create_if_empty);
 101 static ops_list_t *create_driver(char *id);
 102 static void unlock_driver(ops_list_t *ops);
 103 static void remove_drivers(void);
 104
 105 /*
 106  * show all drivers and their status
 107  */
 108
 109 static void snd_seq_device_info(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
 110 {
 111         struct list_head *head;
 112
 113         down(&ops_mutex);
 114         list_for_each(head, &opslist) {
 115                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 116                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 117                                 ops->id,
 118                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 119                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 120                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 121                                 ops->num_devices);
 122         }
 123         up(&ops_mutex);
 124 }
 125
 126 /*
 127  * load all registered drivers (called from seq_clientmgr.c)
 128  */
 129
 130 void snd_seq_device_load_drivers(void)
 131 {
 132 #ifdef CONFIG_KMOD
 133         struct list_head *head;
 134
 135         if (! current->fs->root)
 136                 return;
 137
 138         down(&ops_mutex);
 139         list_for_each(head, &opslist) {
 140                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 141                 if (! (ops->driver & DRIVER_LOADED) &&
 142                     ! (ops->driver & DRIVER_REQUESTED)) {
 143                         ops->used++;
 144                         up(&ops_mutex);
 145                         ops->driver |= DRIVER_REQUESTED;
 146                         request_module("snd-%s", ops->id);
 147                         down(&ops_mutex);
 148                         ops->used--;
 149                 }
 150         }
 151         up(&ops_mutex);
 152 #endif
 153 }
 154
 155 /*
 156  * register a sequencer device
 157  * card = card info (NULL allowed)
 158  * device = device number (if any)
 159  * id = id of driver
 160  * result = return pointer (NULL allowed if unnecessary)
 161  */
 162 int snd_seq_device_new(snd_card_t *card, int device, char *id, int argsize,
 163                        snd_seq_device_t **result)
 164 {
 165         snd_seq_device_t *dev;
 166         ops_list_t *ops;
 167         int err;
 168         static snd_device_ops_t dops = {
 169                 .dev_free = snd_seq_device_dev_free,
 170                 .dev_register = snd_seq_device_dev_register,
 171                 .dev_disconnect = snd_seq_device_dev_disconnect,
 172                 .dev_unregister = snd_seq_device_dev_unregister
 173         };
 174
 175         if (result)
 176                 *result = NULL;
 177
 178         snd_assert(id != NULL, return -EINVAL);
 179
 180         ops = find_driver(id, 1);
 181         if (ops == NULL)
 182                 return -ENOMEM;
 183
 184         dev = snd_magic_kcalloc(snd_seq_device_t, sizeof(*dev) + argsize, GFP_KERNEL);
 185         if (dev == NULL) {
 186                 unlock_driver(ops);
 187                 return -ENOMEM;
 188         }
 189
 190         /* set up device info */
 191         dev->card = card;
 192         dev->device = device;
 193         strlcpy(dev->id, id, sizeof(dev->id));
 194         dev->argsize = argsize;
 195         dev->status = SNDRV_SEQ_DEVICE_FREE;
 196
 197         /* add this device to the list */
 198         down(&ops->reg_mutex);
 199         list_add_tail(&dev->list, &ops->dev_list);
 200         ops->num_devices++;
 201         up(&ops->reg_mutex);
 202
 203         unlock_driver(ops);
 204
 205         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 206                 snd_seq_device_free(dev);
 207                 return err;
 208         }
 209
 210         if (result)
 211                 *result = dev;
 212
 213         return 0;
 214 }
 215
 216 /*
 217  * free the existing device
 218  */
 219 static int snd_seq_device_free(snd_seq_device_t *dev)
 220 {
 221         ops_list_t *ops;
 222
 223         snd_assert(dev != NULL, return -EINVAL);
 224
 225         ops = find_driver(dev->id, 0);
 226         if (ops == NULL)
 227                 return -ENXIO;
 228
 229         /* remove the device from the list */
 230         down(&ops->reg_mutex);
 231         list_del(&dev->list);
 232         ops->num_devices--;
 233         up(&ops->reg_mutex);
 234
 235         free_device(dev, ops);
 236         if (dev->private_free)
 237                 dev->private_free(dev);
 238         snd_magic_kfree(dev);
 239
 240         unlock_driver(ops);
 241
 242         return 0;
 243 }
 244
 245 static int snd_seq_device_dev_free(snd_device_t *device)
 246 {
 247         snd_seq_device_t *dev = snd_magic_cast(snd_seq_device_t, device->device_data, return -ENXIO);
 248         return snd_seq_device_free(dev);
 249 }
 250
 251 /*
 252  * register the device
 253  */
 254 static int snd_seq_device_dev_register(snd_device_t *device)
 255 {
 256         snd_seq_device_t *dev = snd_magic_cast(snd_seq_device_t, device->device_data, return -ENXIO);
 257         ops_list_t *ops;
 258
 259         ops = find_driver(dev->id, 0);
 260         if (ops == NULL)
 261                 return -ENOENT;
 262
 263         /* initialize this device if the corresponding driver was
 264          * already loaded
 265          */
 266         if (ops->driver & DRIVER_LOADED)
 267                 init_device(dev, ops);
 268
 269         unlock_driver(ops);
 270         return 0;
 271 }
 272
 273 /*
 274  * disconnect the device
 275  */
 276 static int snd_seq_device_dev_disconnect(snd_device_t *device)
 277 {
 278         snd_seq_device_t *dev = snd_magic_cast(snd_seq_device_t, device->device_data, return -ENXIO);
 279         ops_list_t *ops;
 280
 281         ops = find_driver(dev->id, 0);
 282         if (ops == NULL)
 283                 return -ENOENT;
 284
 285         free_device(dev, ops);
 286
 287         unlock_driver(ops);
 288         return 0;
 289 }
 290
 291 /*
 292  * unregister the existing device
 293  */
 294 static int snd_seq_device_dev_unregister(snd_device_t *device)
 295 {
 296         snd_seq_device_t *dev = snd_magic_cast(snd_seq_device_t, device->device_data, return -ENXIO);
 297         return snd_seq_device_free(dev);
 298 }
 299
 300 /*
 301  * register device driver
 302  * id = driver id
 303  * entry = driver operators - duplicated to each instance
 304  */
 305 int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsize)
 306 {
 307         struct list_head *head;
 308         ops_list_t *ops;
 309
 310         if (id == NULL || entry == NULL ||
 311             entry->init_device == NULL || entry->free_device == NULL)
 312                 return -EINVAL;
 313
 314         ops = find_driver(id, 1);
 315         if (ops == NULL)
 316                 return -ENOMEM;
 317         if (ops->driver & DRIVER_LOADED) {
 318                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 319                 unlock_driver(ops);
 320                 return -EBUSY;
 321         }
 322
 323         down(&ops->reg_mutex);
 324         /* copy driver operators */
 325         ops->ops = *entry;
 326         ops->driver |= DRIVER_LOADED;
 327         ops->argsize = argsize;
 328
 329         /* initialize existing devices if necessary */
 330         list_for_each(head, &ops->dev_list) {
 331                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
 332                 init_device(dev, ops);
 333         }
 334         up(&ops->reg_mutex);
 335
 336         unlock_driver(ops);
 337
 338         return 0;
 339 }
 340
 341
 342 /*
 343  * create driver record
 344  */
 345 static ops_list_t * create_driver(char *id)
 346 {
 347         ops_list_t *ops;
 348
 349         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
 350         if (ops == NULL)
 351                 return ops;
 352         memset(ops, 0, sizeof(*ops));
 353
 354         /* set up driver entry */
 355         strlcpy(ops->id, id, sizeof(ops->id));
 356         init_MUTEX(&ops->reg_mutex);
 357         ops->driver = DRIVER_EMPTY;
 358         INIT_LIST_HEAD(&ops->dev_list);
 359         /* lock this instance */
 360         ops->used = 1;
 361
 362         /* register driver entry */
 363         down(&ops_mutex);
 364         list_add_tail(&ops->list, &opslist);
 365         num_ops++;
 366         up(&ops_mutex);
 367
 368         return ops;
 369 }
 370
 371
 372 /*
 373  * unregister the specified driver
 374  */
 375 int snd_seq_device_unregister_driver(char *id)
 376 {
 377         struct list_head *head;
 378         ops_list_t *ops;
 379
 380         ops = find_driver(id, 0);
 381         if (ops == NULL)
 382                 return -ENXIO;
 383         if (! (ops->driver & DRIVER_LOADED) ||
 384             (ops->driver & DRIVER_LOCKED)) {
 385                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n", id, ops->driver);
 386                 unlock_driver(ops);
 387                 return -EBUSY;
 388         }
 389
 390         /* close and release all devices associated with this driver */
 391         down(&ops->reg_mutex);
 392         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 393         list_for_each(head, &ops->dev_list) {
 394                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
 395                 free_device(dev, ops);
 396         }
 397
 398         ops->driver = 0;
 399         if (ops->num_init_devices > 0)
 400                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n", ops->num_init_devices);
 401         up(&ops->reg_mutex);
 402
 403         unlock_driver(ops);
 404
 405         /* remove empty driver entries */
 406         remove_drivers();
 407
 408         return 0;
 409 }
 410
 411
 412 /*
 413  * remove empty driver entries
 414  */
 415 static void remove_drivers(void)
 416 {
 417         struct list_head *head;
 418
 419         down(&ops_mutex);
 420         head = opslist.next;
 421         while (head != &opslist) {
 422                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 423                 if (! (ops->driver & DRIVER_LOADED) &&
 424                     ops->used == 0 && ops->num_devices == 0) {
 425                         head = head->next;
 426                         list_del(&ops->list);
 427                         kfree(ops);
 428                         num_ops--;
 429                 } else
 430                         head = head->next;
 431         }
 432         up(&ops_mutex);
 433 }
 434
 435 /*
 436  * initialize the device - call init_device operator
 437  */
 438 static int init_device(snd_seq_device_t *dev, ops_list_t *ops)
 439 {
 440         if (! (ops->driver & DRIVER_LOADED))
 441                 return 0; /* driver is not loaded yet */
 442         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 443                 return 0; /* already initialized */
 444         if (ops->argsize != dev->argsize) {
 445                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize);
 446                 return -EINVAL;
 447         }
 448         if (ops->ops.init_device(dev) >= 0) {
 449                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 450                 ops->num_init_devices++;
 451         } else {
 452                 snd_printk(KERN_ERR "init_device failed: %s: %s\n", dev->name, dev->id);
 453         }
 454
 455         return 0;
 456 }
 457
 458 /*
 459  * release the device - call free_device operator
 460  */
 461 static int free_device(snd_seq_device_t *dev, ops_list_t *ops)
 462 {
 463         int result;
 464
 465         if (! (ops->driver & DRIVER_LOADED))
 466                 return 0; /* driver is not loaded yet */
 467         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 468                 return 0; /* not registered */
 469         if (ops->argsize != dev->argsize) {
 470                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize);
 471                 return -EINVAL;
 472         }
 473         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 474                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 475                 dev->driver_data = NULL;
 476                 ops->num_init_devices--;
 477         } else {
 478                 snd_printk(KERN_ERR "free_device failed: %s: %s\n", dev->name, dev->id);
 479         }
 480
 481         return 0;
 482 }
 483
 484 /*
 485  * find the matching driver with given id
 486  */
 487 static ops_list_t * find_driver(char *id, int create_if_empty)
 488 {
 489         struct list_head *head;
 490
 491         down(&ops_mutex);
 492         list_for_each(head, &opslist) {
 493                 ops_list_t *ops = list_entry(head, ops_list_t, list);
 494                 if (strcmp(ops->id, id) == 0) {
 495                         ops->used++;
 496                         up(&ops_mutex);
 497                         return ops;
 498                 }
 499         }
 500         up(&ops_mutex);
 501         if (create_if_empty)
 502                 return create_driver(id);
 503         return NULL;
 504 }
 505
 506 static void unlock_driver(ops_list_t *ops)
 507 {
 508         down(&ops_mutex);
 509         ops->used--;
 510         up(&ops_mutex);
 511 }
 512
 513
 514 /*
 515  * module part
 516  */
 517
 518 static int __init alsa_seq_device_init(void)
 519 {
 520         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers", snd_seq_root);
 521         if (info_entry == NULL)
 522                 return -ENOMEM;
 523         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 524         info_entry->c.text.read_size = 2048;
 525         info_entry->c.text.read = snd_seq_device_info;
 526         if (snd_info_register(info_entry) < 0) {
 527                 snd_info_free_entry(info_entry);
 528                 return -ENOMEM;
 529         }
 530         return 0;
 531 }
 532
 533 static void __exit alsa_seq_device_exit(void)
 534 {
 535         remove_drivers();
 536         snd_info_unregister(info_entry);
 537         if (num_ops)
 538                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 539 }
 540
 541 module_init(alsa_seq_device_init)
 542 module_exit(alsa_seq_device_exit)
 543
 544 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 545 EXPORT_SYMBOL(snd_seq_device_new);
 546 EXPORT_SYMBOL(snd_seq_device_register_driver);
 547 EXPORT_SYMBOL(snd_seq_device_unregister_driver);