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 #ifdef CONFIG_PROC_FS
  82 static struct snd_info_entry *info_entry = NULL;
  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 static int snd_seq_device_dev_unregister(struct snd_device *device);
  93
  94 static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
  95 static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
  96 static struct ops_list *find_driver(char *id, int create_if_empty);
  97 static struct ops_list *create_driver(char *id);
  98 static void unlock_driver(struct ops_list *ops);
  99 static void remove_drivers(void);
 100
 101 /*
 102  * show all drivers and their status
 103  */
 104
 105 #ifdef CONFIG_PROC_FS
 106 static void snd_seq_device_info(struct snd_info_entry *entry,
 107                                 struct snd_info_buffer *buffer)
 108 {
 109         struct list_head *head;
 110
 111         down(&ops_mutex);
 112         list_for_each(head, &opslist) {
 113                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 114                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
 115                                 ops->id,
 116                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
 117                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
 118                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
 119                                 ops->num_devices);
 120         }
 121         up(&ops_mutex);
 122 }
 123 #endif
 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                 struct ops_list *ops = list_entry(head, struct ops_list, 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(struct snd_card *card, int device, char *id, int argsize,
 182                        struct snd_seq_device **result)
 183 {
 184         struct snd_seq_device *dev;
 185         struct ops_list *ops;
 186         int err;
 187         static struct snd_device_ops 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 = kzalloc(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(struct snd_seq_device *dev)
 239 {
 240         struct ops_list *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(struct snd_device *device)
 265 {
 266         struct snd_seq_device *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(struct snd_device *device)
 274 {
 275         struct snd_seq_device *dev = device->device_data;
 276         struct ops_list *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(struct snd_device *device)
 296 {
 297         struct snd_seq_device *dev = device->device_data;
 298         struct ops_list *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(struct snd_device *device)
 314 {
 315         struct snd_seq_device *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, struct snd_seq_dev_ops *entry,
 325                                    int argsize)
 326 {
 327         struct list_head *head;
 328         struct ops_list *ops;
 329
 330         if (id == NULL || entry == NULL ||
 331             entry->init_device == NULL || entry->free_device == NULL)
 332                 return -EINVAL;
 333
 334         snd_seq_autoload_lock();
 335         ops = find_driver(id, 1);
 336         if (ops == NULL) {
 337                 snd_seq_autoload_unlock();
 338                 return -ENOMEM;
 339         }
 340         if (ops->driver & DRIVER_LOADED) {
 341                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
 342                 unlock_driver(ops);
 343                 snd_seq_autoload_unlock();
 344                 return -EBUSY;
 345         }
 346
 347         down(&ops->reg_mutex);
 348         /* copy driver operators */
 349         ops->ops = *entry;
 350         ops->driver |= DRIVER_LOADED;
 351         ops->argsize = argsize;
 352
 353         /* initialize existing devices if necessary */
 354         list_for_each(head, &ops->dev_list) {
 355                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 356                 init_device(dev, ops);
 357         }
 358         up(&ops->reg_mutex);
 359
 360         unlock_driver(ops);
 361         snd_seq_autoload_unlock();
 362
 363         return 0;
 364 }
 365
 366
 367 /*
 368  * create driver record
 369  */
 370 static struct ops_list * create_driver(char *id)
 371 {
 372         struct ops_list *ops;
 373
 374         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
 375         if (ops == NULL)
 376                 return ops;
 377         memset(ops, 0, sizeof(*ops));
 378
 379         /* set up driver entry */
 380         strlcpy(ops->id, id, sizeof(ops->id));
 381         init_MUTEX(&ops->reg_mutex);
 382         ops->driver = DRIVER_EMPTY;
 383         INIT_LIST_HEAD(&ops->dev_list);
 384         /* lock this instance */
 385         ops->used = 1;
 386
 387         /* register driver entry */
 388         down(&ops_mutex);
 389         list_add_tail(&ops->list, &opslist);
 390         num_ops++;
 391         up(&ops_mutex);
 392
 393         return ops;
 394 }
 395
 396
 397 /*
 398  * unregister the specified driver
 399  */
 400 int snd_seq_device_unregister_driver(char *id)
 401 {
 402         struct list_head *head;
 403         struct ops_list *ops;
 404
 405         ops = find_driver(id, 0);
 406         if (ops == NULL)
 407                 return -ENXIO;
 408         if (! (ops->driver & DRIVER_LOADED) ||
 409             (ops->driver & DRIVER_LOCKED)) {
 410                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
 411                            id, ops->driver);
 412                 unlock_driver(ops);
 413                 return -EBUSY;
 414         }
 415
 416         /* close and release all devices associated with this driver */
 417         down(&ops->reg_mutex);
 418         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
 419         list_for_each(head, &ops->dev_list) {
 420                 struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
 421                 free_device(dev, ops);
 422         }
 423
 424         ops->driver = 0;
 425         if (ops->num_init_devices > 0)
 426                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
 427                            ops->num_init_devices);
 428         up(&ops->reg_mutex);
 429
 430         unlock_driver(ops);
 431
 432         /* remove empty driver entries */
 433         remove_drivers();
 434
 435         return 0;
 436 }
 437
 438
 439 /*
 440  * remove empty driver entries
 441  */
 442 static void remove_drivers(void)
 443 {
 444         struct list_head *head;
 445
 446         down(&ops_mutex);
 447         head = opslist.next;
 448         while (head != &opslist) {
 449                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 450                 if (! (ops->driver & DRIVER_LOADED) &&
 451                     ops->used == 0 && ops->num_devices == 0) {
 452                         head = head->next;
 453                         list_del(&ops->list);
 454                         kfree(ops);
 455                         num_ops--;
 456                 } else
 457                         head = head->next;
 458         }
 459         up(&ops_mutex);
 460 }
 461
 462 /*
 463  * initialize the device - call init_device operator
 464  */
 465 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
 466 {
 467         if (! (ops->driver & DRIVER_LOADED))
 468                 return 0; /* driver is not loaded yet */
 469         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
 470                 return 0; /* already initialized */
 471         if (ops->argsize != dev->argsize) {
 472                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 473                            dev->name, ops->id, ops->argsize, dev->argsize);
 474                 return -EINVAL;
 475         }
 476         if (ops->ops.init_device(dev) >= 0) {
 477                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
 478                 ops->num_init_devices++;
 479         } else {
 480                 snd_printk(KERN_ERR "init_device failed: %s: %s\n",
 481                            dev->name, dev->id);
 482         }
 483
 484         return 0;
 485 }
 486
 487 /*
 488  * release the device - call free_device operator
 489  */
 490 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
 491 {
 492         int result;
 493
 494         if (! (ops->driver & DRIVER_LOADED))
 495                 return 0; /* driver is not loaded yet */
 496         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
 497                 return 0; /* not registered */
 498         if (ops->argsize != dev->argsize) {
 499                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
 500                            dev->name, ops->id, ops->argsize, dev->argsize);
 501                 return -EINVAL;
 502         }
 503         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
 504                 dev->status = SNDRV_SEQ_DEVICE_FREE;
 505                 dev->driver_data = NULL;
 506                 ops->num_init_devices--;
 507         } else {
 508                 snd_printk(KERN_ERR "free_device failed: %s: %s\n",
 509                            dev->name, dev->id);
 510         }
 511
 512         return 0;
 513 }
 514
 515 /*
 516  * find the matching driver with given id
 517  */
 518 static struct ops_list * find_driver(char *id, int create_if_empty)
 519 {
 520         struct list_head *head;
 521
 522         down(&ops_mutex);
 523         list_for_each(head, &opslist) {
 524                 struct ops_list *ops = list_entry(head, struct ops_list, list);
 525                 if (strcmp(ops->id, id) == 0) {
 526                         ops->used++;
 527                         up(&ops_mutex);
 528                         return ops;
 529                 }
 530         }
 531         up(&ops_mutex);
 532         if (create_if_empty)
 533                 return create_driver(id);
 534         return NULL;
 535 }
 536
 537 static void unlock_driver(struct ops_list *ops)
 538 {
 539         down(&ops_mutex);
 540         ops->used--;
 541         up(&ops_mutex);
 542 }
 543
 544
 545 /*
 546  * module part
 547  */
 548
 549 static int __init alsa_seq_device_init(void)
 550 {
 551 #ifdef CONFIG_PROC_FS
 552         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 553                                                   snd_seq_root);
 554         if (info_entry == NULL)
 555                 return -ENOMEM;
 556         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 557         info_entry->c.text.read_size = 2048;
 558         info_entry->c.text.read = snd_seq_device_info;
 559         if (snd_info_register(info_entry) < 0) {
 560                 snd_info_free_entry(info_entry);
 561                 return -ENOMEM;
 562         }
 563 #endif
 564         return 0;
 565 }
 566
 567 static void __exit alsa_seq_device_exit(void)
 568 {
 569         remove_drivers();
 570 #ifdef CONFIG_PROC_FS
 571         snd_info_unregister(info_entry);
 572 #endif
 573         if (num_ops)
 574                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
 575 }
 576
 577 module_init(alsa_seq_device_init)
 578 module_exit(alsa_seq_device_exit)
 579
 580 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 581 EXPORT_SYMBOL(snd_seq_device_new);
 582 EXPORT_SYMBOL(snd_seq_device_register_driver);
 583 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
 584 #ifdef CONFIG_KMOD
 585 EXPORT_SYMBOL(snd_seq_autoload_lock);
 586 EXPORT_SYMBOL(snd_seq_autoload_unlock);
 587 #endif