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