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 #else
 152 #define queue_autoload_drivers() /* NOP */
 153 #endif
 154
 155 /*
 156  * device management
 157  */
 158 static int snd_seq_device_dev_free(struct snd_device *device)
 159 {
 160         struct snd_seq_device *dev = device->device_data;
 161
 162         put_device(&dev->dev);
 163         return 0;
 164 }
 165
 166 static int snd_seq_device_dev_register(struct snd_device *device)
 167 {
 168         struct snd_seq_device *dev = device->device_data;
 169         int err;
 170
 171         err = device_add(&dev->dev);
 172         if (err < 0)
 173                 return err;
 174         if (!dev->dev.driver)
 175                 queue_autoload_drivers();
 176         return 0;
 177 }
 178
 179 static int snd_seq_device_dev_disconnect(struct snd_device *device)
 180 {
 181         struct snd_seq_device *dev = device->device_data;
 182
 183         device_del(&dev->dev);
 184         return 0;
 185 }
 186
 187 static void snd_seq_dev_release(struct device *dev)
 188 {
 189         struct snd_seq_device *sdev = to_seq_dev(dev);
 190
 191         if (sdev->private_free)
 192                 sdev->private_free(sdev);
 193         kfree(sdev);
 194 }
 195
 196 /*
 197  * register a sequencer device
 198  * card = card info
 199  * device = device number (if any)
 200  * id = id of driver
 201  * result = return pointer (NULL allowed if unnecessary)
 202  */
 203 int snd_seq_device_new(struct snd_card *card, int device, const char *id,
 204                        int argsize, struct snd_seq_device **result)
 205 {
 206         struct snd_seq_device *dev;
 207         int err;
 208         static struct snd_device_ops dops = {
 209                 .dev_free = snd_seq_device_dev_free,
 210                 .dev_register = snd_seq_device_dev_register,
 211                 .dev_disconnect = snd_seq_device_dev_disconnect,
 212         };
 213
 214         if (result)
 215                 *result = NULL;
 216
 217         if (snd_BUG_ON(!id))
 218                 return -EINVAL;
 219
 220         dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
 221         if (!dev)
 222                 return -ENOMEM;
 223
 224         /* set up device info */
 225         dev->card = card;
 226         dev->device = device;
 227         dev->id = id;
 228         dev->argsize = argsize;
 229
 230         device_initialize(&dev->dev);
 231         dev->dev.parent = &card->card_dev;
 232         dev->dev.bus = &snd_seq_bus_type;
 233         dev->dev.release = snd_seq_dev_release;
 234         dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);
 235
 236         /* add this device to the list */
 237         err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
 238         if (err < 0) {
 239                 put_device(&dev->dev);
 240                 return err;
 241         }
 242
 243         if (result)
 244                 *result = dev;
 245
 246         return 0;
 247 }
 248 EXPORT_SYMBOL(snd_seq_device_new);
 249
 250 /*
 251  * driver registration
 252  */
 253 int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)
 254 {
 255         if (WARN_ON(!drv->driver.name || !drv->id))
 256                 return -EINVAL;
 257         drv->driver.bus = &snd_seq_bus_type;
 258         drv->driver.owner = mod;
 259         return driver_register(&drv->driver);
 260 }
 261 EXPORT_SYMBOL_GPL(__snd_seq_driver_register);
 262
 263 void snd_seq_driver_unregister(struct snd_seq_driver *drv)
 264 {
 265         driver_unregister(&drv->driver);
 266 }
 267 EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);
 268
 269 /*
 270  * module part
 271  */
 272
 273 static int __init seq_dev_proc_init(void)
 274 {
 275 #ifdef CONFIG_SND_PROC_FS
 276         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
 277                                                   snd_seq_root);
 278         if (info_entry == NULL)
 279                 return -ENOMEM;
 280         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
 281         info_entry->c.text.read = snd_seq_device_info;
 282         if (snd_info_register(info_entry) < 0) {
 283                 snd_info_free_entry(info_entry);
 284                 return -ENOMEM;
 285         }
 286 #endif
 287         return 0;
 288 }
 289
 290 static int __init alsa_seq_device_init(void)
 291 {
 292         int err;
 293
 294         err = bus_register(&snd_seq_bus_type);
 295         if (err < 0)
 296                 return err;
 297         err = seq_dev_proc_init();
 298         if (err < 0)
 299                 bus_unregister(&snd_seq_bus_type);
 300         return err;
 301 }
 302
 303 static void __exit alsa_seq_device_exit(void)
 304 {
 305 #ifdef CONFIG_MODULES
 306         cancel_work_sync(&autoload_work);
 307 #endif
 308 #ifdef CONFIG_SND_PROC_FS
 309         snd_info_free_entry(info_entry);
 310 #endif
 311         bus_unregister(&snd_seq_bus_type);
 312 }
 313
 314 subsys_initcall(alsa_seq_device_init)
 315 module_exit(alsa_seq_device_exit)