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 /* 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 semaphore 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 DECLARE_MUTEX(ops_mutex);
  81 static struct snd_info_entry *info_entry = NULL;
  82
  83 /*
  84  * prototypes
  85  */
  86 static int snd_seq_device_free(struct snd_seq_device *dev);
  87 static int snd_seq_device_dev_free(struct snd_device *device);
  88 static int snd_seq_device_dev_register(struct snd_device *device);
  89 static int snd_seq_device_dev_disconnect(struct snd_device *device);
  90 static int snd_seq_device_dev_unregister(struct snd_device *device);
  91
  92 static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
  93 static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
  94 static struct ops_list *find_driver(char *id, int create_if_empty);
  95 static struct ops_list *create_driver(char *id);
  96 static void unlock_driver(struct ops_list *ops);
  97 static void remove_drivers(void);
  98
  99 /*
 100  * show all drivers and their status
 101  */
 102
 103 static void snd_seq_device_info(struct snd_info_entry *entry,
 104                                 struct snd_info_buffer *buffer)
 105 {
 106         struct list_head *head;
 107
 108         down(&ops_mutex);
 109         list_for_each(head, &opslist) {
 110                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 111                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 112                                 ops->id,
 113                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 114                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 115                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 116                                 ops->num_devices);
 117         }
 118         up(&ops_mutex);
 119 }
 120
 121 /*
 122  * load all registered drivers (called from seq_clientmgr.c)
 123  */
 124
 125 #ifdef CONFIG_KMOD
 126 /* avoid auto-loading during module_init() */
 127 static int snd_seq_in_init;
 128 void snd_seq_autoload_lock(void)
 129 {
 130         snd_seq_in_init++;
 131 }
 132
 133 void snd_seq_autoload_unlock(void)
 134 {
 135         snd_seq_in_init--;
 136 }
 137 #endif
 138
 139 void snd_seq_device_load_drivers(void)
 140 {
 141 #ifdef CONFIG_KMOD
 142         struct list_head *head;
 143
 144         /* Calling request_module during module_init()
 145          * may cause blocking.
 146          */
 147         if (snd_seq_in_init)
 148                 return;
 149
 150         if (! current->fs->root)
 151                 return;
 152
 153         down(&ops_mutex);
 154         list_for_each(head, &opslist) {
 155                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 156                 if (! (ops->driver & DRIVER_LOADED) &&
 157                     ! (ops->driver & DRIVER_REQUESTED)) {
 158                         ops->used++;
 159                         up(&ops_mutex);
 160                         ops->driver |= DRIVER_REQUESTED;
 161                         request_module("snd-%s", ops->id);
 162                         down(&ops_mutex);
 163                         ops->used--;
 164                 }
 165         }
 166         up(&ops_mutex);
 167 #endif
 168 }
 169
 170 /*
 171  * register a sequencer device
 172  * card = card info (NULL allowed)
 173  * device = device number (if any)
 174  * id = id of driver
 175  * result = return pointer (NULL allowed if unnecessary)
 176  */
 177 int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
 178                        struct snd_seq_device **result)
 179 {
 180         struct snd_seq_device *dev;
 181         struct ops_list *ops;
 182         int err;
 183         static struct snd_device_ops dops = {
 184                 .dev_free = snd_seq_device_dev_free,
 185                 .dev_register = snd_seq_device_dev_register,
 186                 .dev_disconnect = snd_seq_device_dev_disconnect,
 187                 .dev_unregister = snd_seq_device_dev_unregister
 188         };
 189
 190         if (result)
 191                 *result = NULL;
 192
 193         snd_assert(id != NULL, return -EINVAL);
 194
 195         ops = find_driver(id, 1);
 196         if (ops == NULL)
 197                 return -ENOMEM;
 198
 199         dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
 200         if (dev == NULL) {
 201                 unlock_driver(ops);
 202                 return -ENOMEM;
 203         }
 204
 205         /* set up device info */
 206         dev->card = card;
 207         dev->device = device;
 208         strlcpy(dev->id, id, sizeof(dev->id));
 209         dev->argsize = argsize;
 210         dev->status = SNDRV_SEQ_DEVICE_FREE;
 211
 212         /* add this device to the list */
 213         down(&ops->reg_mutex);
 214         list_add_tail(&dev->list, &ops->dev_list);
 215         ops->num_devices++;
 216         up(&ops->reg_mutex);
 217
 218         unlock_driver(ops);
 219
 220         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
 221                 snd_seq_device_free(dev);
 222                 return err;
 223         }
 224
 225         if (result)
 226                 *result = dev;
 227
 228         return 0;
 229 }
 230
 231 /*
 232  * free the existing device
 233  */
 234 static int snd_seq_device_free(struct snd_seq_device *dev)
 235 {
 236         struct ops_list *ops;
 237
 238         snd_assert(dev != NULL, return -EINVAL);
 239
 240         ops = find_driver(dev->id, 0);
 241         if (ops == NULL)
 242                 return -ENXIO;
 243
 244         /* remove the device from the list */
 245         down(&ops->reg_mutex);
 246         list_del(&dev->list);
 247         ops->num_devices--;
 248         up(&ops->reg_mutex);
 249
 250         free_device(dev, ops);
 251         if (dev->private_free)
 252                 dev->private_free(dev);
 253         kfree(dev);
 254
 255         unlock_driver(ops);
 256
 257         return 0;
 258 }
 259
 260 static int snd_seq_device_dev_free(struct snd_device *device)
 261 {
 262         struct snd_seq_device *dev = device->device_data;
 263         return snd_seq_device_free(dev);
 264 }
 265
 266 /*
 267  * register the device
 268  */
 269 static int snd_seq_device_dev_register(struct snd_device *device)
 270 {
 271         struct snd_seq_device *dev = device->device_data;
 272         struct ops_list *ops;
 273
 274         ops = find_driver(dev->id, 0);
 275         if (ops == NULL)
 276                 return -ENOENT;
 277
 278         /* initialize this device if the corresponding driver was
 279          * already loaded
 280          */
 281         if (ops->driver & DRIVER_LOADED)
 282                 init_device(dev, ops);
 283
 284         unlock_driver(ops);
 285         return 0;
 286 }
 287
 288 /*
 289  * disconnect the device
 290  */
 291 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 292 {
 293         struct snd_seq_device *dev = device->device_data;
 294         struct ops_list *ops;
 295
 296         ops = find_driver(dev->id, 0);
 297         if (ops == NULL)
 298                 return -ENOENT;
 299
 300         free_device(dev, ops);
 301
 302         unlock_driver(ops);
 303         return 0;
 304 }
 305
 306 /*
 307  * unregister the existing device
 308  */
 309 static int snd_seq_device_dev_unregister(struct snd_device *device)
 310 {
 311         struct snd_seq_device *dev = device->device_data;
 312         return snd_seq_device_free(dev);
 313 }
 314
 315 /*
 316  * register device driver
 317  * id = driver id
 318  * entry = driver operators - duplicated to each instance
 319  */
 320 int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
 321                                    int argsize)
 322 {
 323         struct list_head *head;
 324         struct ops_list *ops;
 325
 326         if (id == NULL || entry == NULL ||
 327             entry->init_device == NULL || entry->free_device == NULL)
 328                 return -EINVAL;
 329
 330         snd_seq_autoload_lock();
 331         ops = find_driver(id, 1);
 332         if (ops == NULL) {
 333                 snd_seq_autoload_unlock();
 334                 return -ENOMEM;
 335         }
 336         if (ops->driver & DRIVER_LOADED) {
 337                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 338                 unlock_driver(ops);
 339                 snd_seq_autoload_unlock();
 340                 return -EBUSY;
 341         }
 342
 343         down(&ops->reg_mutex);
 344         /* copy driver operators */
 345         ops->ops = *entry;
 346         ops->driver |= DRIVER_LOADED;
 347         ops->argsize = argsize;
 348
 349         /* initialize existing devices if necessary */
 350         list_for_each(head, &ops->dev_list) {
 351                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 352                 init_device(dev, ops);
 353         }
 354         up(&ops->reg_mutex);
 355
 356         unlock_driver(ops);
 357         snd_seq_autoload_unlock();
 358
 359         return 0;
 360 }
 361
 362
 363 /*
 364  * create driver record
 365  */
 366 static struct ops_list * create_driver(char *id)
 367 {
 368         struct ops_list *ops;
 369
 370         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
 371         if (ops == NULL)
 372                 return ops;
 373         memset(ops, 0, sizeof(*ops));
 374
 375         /* set up driver entry */
 376         strlcpy(ops->id, id, sizeof(ops->id));
 377         init_MUTEX(&ops->reg_mutex);
 378         ops->driver = DRIVER_EMPTY;
 379         INIT_LIST_HEAD(&ops->dev_list);
 380         /* lock this instance */
 381         ops->used = 1;
 382
 383         /* register driver entry */
 384         down(&ops_mutex);
 385         list_add_tail(&ops->list, &opslist);
 386         num_ops++;
 387         up(&ops_mutex);
 388
 389         return ops;
 390 }
 391
 392
 393 /*
 394  * unregister the specified driver
 395  */
 396 int snd_seq_device_unregister_driver(char *id)
 397 {
 398         struct list_head *head;
 399         struct ops_list *ops;
 400
 401         ops = find_driver(id, 0);
 402         if (ops == NULL)
 403                 return -ENXIO;
 404         if (! (ops->driver & DRIVER_LOADED) ||
 405             (ops->driver & DRIVER_LOCKED)) {
 406                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
 407                            id, ops->driver);
 408                 unlock_driver(ops);
 409                 return -EBUSY;
 410         }
 411
 412         /* close and release all devices associated with this driver */
 413         down(&ops->reg_mutex);
 414         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 415         list_for_each(head, &ops->dev_list) {
 416                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 417                 free_device(dev, ops);
 418         }
 419
 420         ops->driver = 0;
 421         if (ops->num_init_devices > 0)
 422                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
 423                            ops->num_init_devices);
 424         up(&ops->reg_mutex);
 425
 426         unlock_driver(ops);
 427
 428         /* remove empty driver entries */
 429         remove_drivers();
 430
 431         return 0;
 432 }
 433
 434
 435 /*
 436  * remove empty driver entries
 437  */
 438 static void remove_drivers(void)
 439 {
 440         struct list_head *head;
 441
 442         down(&ops_mutex);
 443         head = opslist.next;
 444         while (head != &opslist) {
 445                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 446                 if (! (ops->driver & DRIVER_LOADED) &&
 447                     ops->used == 0 && ops->num_devices == 0) {
 448                         head = head->next;
 449                         list_del(&ops->list);
 450                         kfree(ops);
 451                         num_ops--;
 452                 } else
 453                         head = head->next;
 454         }
 455         up(&ops_mutex);
 456 }
 457
 458 /*
 459  * initialize the device - call init_device operator
 460  */
 461 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
 462 {
 463         if (! (ops->driver & DRIVER_LOADED))
 464                 return 0; /* driver is not loaded yet */
 465         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 466                 return 0; /* already initialized */
 467         if (ops->argsize != dev->argsize) {
 468                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 469                            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",
 477                            dev->name, dev->id);
 478         }
 479
 480         return 0;
 481 }
 482
 483 /*
 484  * release the device - call free_device operator
 485  */
 486 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
 487 {
 488         int result;
 489
 490         if (! (ops->driver & DRIVER_LOADED))
 491                 return 0; /* driver is not loaded yet */
 492         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 493                 return 0; /* not registered */
 494         if (ops->argsize != dev->argsize) {
 495                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 496                            dev->name, ops->id, ops->argsize, dev->argsize);
 497                 return -EINVAL;
 498         }
 499         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 500                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 501                 dev->driver_data = NULL;
 502                 ops->num_init_devices--;
 503         } else {
 504                 snd_printk(KERN_ERR "free_device failed: %s: %s\n",
 505                            dev->name, dev->id);
 506         }
 507
 508         return 0;
 509 }
 510
 511 /*
 512  * find the matching driver with given id
 513  */
 514 static struct ops_list * find_driver(char *id, int create_if_empty)
 515 {
 516         struct list_head *head;
 517
 518         down(&ops_mutex);
 519         list_for_each(head, &opslist) {
 520                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 521                 if (strcmp(ops->id, id) == 0) {
 522                         ops->used++;
 523                         up(&ops_mutex);
 524                         return ops;
 525                 }
 526         }
 527         up(&ops_mutex);
 528         if (create_if_empty)
 529                 return create_driver(id);
 530         return NULL;
 531 }
 532
 533 static void unlock_driver(struct ops_list *ops)
 534 {
 535         down(&ops_mutex);
 536         ops->used--;
 537         up(&ops_mutex);
 538 }
 539
 540
 541 /*
 542  * module part
 543  */
 544
 545 static int __init alsa_seq_device_init(void)
 546 {
 547         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 548                                                   snd_seq_root);
 549         if (info_entry == NULL)
 550                 return -ENOMEM;
 551         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 552         info_entry->c.text.read_size = 2048;
 553         info_entry->c.text.read = snd_seq_device_info;
 554         if (snd_info_register(info_entry) < 0) {
 555                 snd_info_free_entry(info_entry);
 556                 return -ENOMEM;
 557         }
 558         return 0;
 559 }
 560
 561 static void __exit alsa_seq_device_exit(void)
 562 {
 563         remove_drivers();
 564         snd_info_unregister(info_entry);
 565         if (num_ops)
 566                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 567 }
 568
 569 module_init(alsa_seq_device_init)
 570 module_exit(alsa_seq_device_exit)
 571
 572 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 573 EXPORT_SYMBOL(snd_seq_device_new);
 574 EXPORT_SYMBOL(snd_seq_device_register_driver);
 575 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 576 #ifdef CONFIG_KMOD
 577 EXPORT_SYMBOL(snd_seq_autoload_lock);
 578 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 579 #endif