sound/core/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 <linux/device.h>
  40 #include <linux/init.h>
  41 #include <linux/module.h>
  42 #include <sound/core.h>
  43 #include <sound/info.h>
  44 #include <sound/seq_device.h>
  45 #include <sound/seq_kernel.h>
  46 #include <sound/initval.h>
  47 #include <linux/kmod.h>
  48 #include <linux/slab.h>
  49 #include <linux/mutex.h>
  50
  51 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  52 MODULE_DESCRIPTION("ALSA sequencer device management");
  53 MODULE_LICENSE("GPL");
  54
  55 /*
  56  * bus definition
  57  */
  58 static int snd_seq_bus_match(struct device *dev, struct device_driver *drv)
  59 {
  60         struct snd_seq_device *sdev = to_seq_dev(dev);
  61         struct snd_seq_driver *sdrv = to_seq_drv(drv);
  62
  63         return strcmp(sdrv->id, sdev->id) == 0 &&
  64                 sdrv->argsize == sdev->argsize;
  65 }
  66
  67 static struct bus_type snd_seq_bus_type = {
  68         .name = "snd_seq",
  69         .match = snd_seq_bus_match,
  70 };
  71
  72 /*
  73  * proc interface -- just for compatibility
  74  */
  75 #ifdef CONFIG_SND_PROC_FS
  76 static struct snd_info_entry *info_entry;
  77
  78 static int print_dev_info(struct device *dev, void *data)
  79 {
  80         struct snd_seq_device *sdev = to_seq_dev(dev);
  81         struct snd_info_buffer *buffer = data;
  82
  83         snd_iprintf(buffer, "snd-%s,%s,%d\n", sdev->id,
  84                     dev->driver ? "loaded" : "empty",
  85                     dev->driver ? 1 : 0);
  86         return 0;
  87 }
  88
  89 static void snd_seq_device_info(struct snd_info_entry *entry,
  90                                 struct snd_info_buffer *buffer)
  91 {
  92         bus_for_each_dev(&snd_seq_bus_type, NULL, buffer, print_dev_info);
  93 }
  94 #endif
  95
  96 /*
  97  * load all registered drivers (called from seq_clientmgr.c)
  98  */
  99
 100 #ifdef CONFIG_MODULES
 101 /* flag to block auto-loading */
 102 static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */
 103
 104 static int request_seq_drv(struct device *dev, void *data)
 105 {
 106         struct snd_seq_device *sdev = to_seq_dev(dev);
 107
 108         if (!dev->driver)
 109                 request_module("snd-%s", sdev->id);
 110         return 0;
 111 }
 112
 113 static void autoload_drivers(struct work_struct *work)
 114 {
 115         /* avoid reentrance */
 116         if (atomic_inc_return(&snd_seq_in_init) == 1)
 117                 bus_for_each_dev(&snd_seq_bus_type, NULL, NULL,
 118                                  request_seq_drv);
 119         atomic_dec(&snd_seq_in_init);
 120 }
 121
 122 static DECLARE_WORK(autoload_work, autoload_drivers);
 123
 124 static void queue_autoload_drivers(void)
 125 {
 126         schedule_work(&autoload_work);
 127 }
 128
 129 void snd_seq_autoload_init(void)
 130 {
 131         atomic_dec(&snd_seq_in_init);
 132 #ifdef CONFIG_SND_SEQUENCER_MODULE
 133         /* initial autoload only when snd-seq is a module */
 134         queue_autoload_drivers();
 135 #endif
 136 }
 137 EXPORT_SYMBOL(snd_seq_autoload_init);
 138
 139 void snd_seq_autoload_exit(void)
 140 {
 141         atomic_inc(&snd_seq_in_init);
 142 }
 143 EXPORT_SYMBOL(snd_seq_autoload_exit);
 144
 145 void snd_seq_device_load_drivers(void)
 146 {
 147         queue_autoload_drivers();
 148         flush_work(&autoload_work);
 149 }
 150 EXPORT_SYMBOL(snd_seq_device_load_drivers);
 151 #define cancel_autoload_drivers()       cancel_work_sync(&autoload_work)
 152 #else
 153 #define queue_autoload_drivers() /* NOP */
 154 #define cancel_autoload_drivers() /* NOP */
 155 #endif
 156
 157 /*
 158  * device management
 159  */
 160 static int snd_seq_device_dev_free(struct snd_device *device)
 161 {
 162         struct snd_seq_device *dev = device->device_data;
 163
 164         cancel_autoload_drivers();
 165         put_device(&dev->dev);
 166         return 0;
 167 }
 168
 169 static int snd_seq_device_dev_register(struct snd_device *device)
 170 {
 171         struct snd_seq_device *dev = device->device_data;
 172         int err;
 173
 174         err = device_add(&dev->dev);
 175         if (err < 0)
 176                 return err;
 177         if (!dev->dev.driver)
 178                 queue_autoload_drivers();
 179         return 0;
 180 }
 181
 182 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 183 {
 184         struct snd_seq_device *dev = device->device_data;
 185
 186         device_del(&dev->dev);
 187         return 0;
 188 }
 189
 190 static void snd_seq_dev_release(struct device *dev)
 191 {
 192         struct snd_seq_device *sdev = to_seq_dev(dev);
 193
 194         if (sdev->private_free)
 195                 sdev->private_free(sdev);
 196         kfree(sdev);
 197 }
 198
 199 /*
 200  * register a sequencer device
 201  * card = card info
 202  * device = device number (if any)
 203  * id = id of driver
 204  * result = return pointer (NULL allowed if unnecessary)
 205  */
 206 int snd_seq_device_new(struct snd_card *card, int device, const char *id,
 207                        int argsize, struct snd_seq_device **result)
 208 {
 209         struct snd_seq_device *dev;
 210         int err;
 211         static struct snd_device_ops dops = {
 212                 .dev_free = snd_seq_device_dev_free,
 213                 .dev_register = snd_seq_device_dev_register,
 214                 .dev_disconnect = snd_seq_device_dev_disconnect,
 215         };
 216
 217         if (result)
 218                 *result = NULL;
 219
 220         if (snd_BUG_ON(!id))
 221                 return -EINVAL;
 222
 223         dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
 224         if (!dev)
 225                 return -ENOMEM;
 226
 227         /* set up device info */
 228         dev->card = card;
 229         dev->device = device;
 230         dev->id = id;
 231         dev->argsize = argsize;
 232
 233         device_initialize(&dev->dev);
 234         dev->dev.parent = &card->card_dev;
 235         dev->dev.bus = &snd_seq_bus_type;
 236         dev->dev.release = snd_seq_dev_release;
 237         dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);
 238
 239         /* add this device to the list */
 240         err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
 241         if (err < 0) {
 242                 put_device(&dev->dev);
 243                 return err;
 244         }
 245
 246         if (result)
 247                 *result = dev;
 248
 249         return 0;
 250 }
 251 EXPORT_SYMBOL(snd_seq_device_new);
 252
 253 /*
 254  * driver registration
 255  */
 256 int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)
 257 {
 258         if (WARN_ON(!drv->driver.name || !drv->id))
 259                 return -EINVAL;
 260         drv->driver.bus = &snd_seq_bus_type;
 261         drv->driver.owner = mod;
 262         return driver_register(&drv->driver);
 263 }
 264 EXPORT_SYMBOL_GPL(__snd_seq_driver_register);
 265
 266 void snd_seq_driver_unregister(struct snd_seq_driver *drv)
 267 {
 268         driver_unregister(&drv->driver);
 269 }
 270 EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);
 271
 272 /*
 273  * module part
 274  */
 275
 276 static int __init seq_dev_proc_init(void)
 277 {
 278 #ifdef CONFIG_SND_PROC_FS
 279         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 280                                                   snd_seq_root);
 281         if (info_entry == NULL)
 282                 return -ENOMEM;
 283         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 284         info_entry->c.text.read = snd_seq_device_info;
 285         if (snd_info_register(info_entry) < 0) {
 286                 snd_info_free_entry(info_entry);
 287                 return -ENOMEM;
 288         }
 289 #endif
 290         return 0;
 291 }
 292
 293 static int __init alsa_seq_device_init(void)
 294 {
 295         int err;
 296
 297         err = bus_register(&snd_seq_bus_type);
 298         if (err < 0)
 299                 return err;
 300         err = seq_dev_proc_init();
 301         if (err < 0)
 302                 bus_unregister(&snd_seq_bus_type);
 303         return err;
 304 }
 305
 306 static void __exit alsa_seq_device_exit(void)
 307 {
 308 #ifdef CONFIG_MODULES
 309         cancel_work_sync(&autoload_work);
 310 #endif
 311 #ifdef CONFIG_SND_PROC_FS
 312         snd_info_free_entry(info_entry);
 313 #endif
 314         bus_unregister(&snd_seq_bus_type);
 315 }
 316
 317 subsys_initcall(alsa_seq_device_init)
 318 module_exit(alsa_seq_device_exit)