/*
   *  ALSA sequencer device management
   *  Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
   *
   *   This program is free software; you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License as published by
   *   the Free Software Foundation; either version 2 of the License, or
   *   (at your option) any later version.
   *
   *   This program is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *   GNU General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License
   *   along with this program; if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   *
   *----------------------------------------------------------------
   *
   * This device handler separates the card driver module from sequencer
   * stuff (sequencer core, synth drivers, etc), so that user can avoid
   * to spend unnecessary resources e.g. if he needs only listening to
   * MP3s.
   *
   * The card (or lowlevel) driver creates a sequencer device entry
   * via snd_seq_device_new().  This is an entry pointer to communicate
   * with the sequencer device "driver", which is involved with the
   * actual part to communicate with the sequencer core.
   * Each sequencer device entry has an id string and the corresponding
   * driver with the same id is loaded when required.  For example,
   * lowlevel codes to access emu8000 chip on sbawe card are included in
   * emu8000-synth module.  To activate this module, the hardware
   * resources like i/o port are passed via snd_seq_device argument.
   *
   */

  #include <linux/device.h>

  #include <linux/init.h>

  #include <linux/module.h>

  #include <sound/core.h>
  #include <sound/info.h>
  #include <sound/seq_device.h>
  #include <sound/seq_kernel.h>
  #include <sound/initval.h>
  #include <linux/kmod.h>
  #include <linux/slab.h>

  #include <linux/mutex.h>

  
  MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  MODULE_DESCRIPTION("ALSA sequencer device management");
  MODULE_LICENSE("GPL");

  /*
   * bus definition
   */
  static int snd_seq_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct snd_seq_device *sdev = to_seq_dev(dev);
  	struct snd_seq_driver *sdrv = to_seq_drv(drv);

  	return strcmp(sdrv->id, sdev->id) == 0 &&
  		sdrv->argsize == sdev->argsize;
  }

  static struct bus_type snd_seq_bus_type = {
  	.name = "snd_seq",
  	.match = snd_seq_bus_match,

  };

  /*
   * proc interface -- just for compatibility
   */

  #ifdef CONFIG_SND_PROC_FS

  static struct snd_info_entry *info_entry;

  static int print_dev_info(struct device *dev, void *data)
  {
  	struct snd_seq_device *sdev = to_seq_dev(dev);
  	struct snd_info_buffer *buffer = data;

  	snd_iprintf(buffer, "snd-%s,%s,%d
  ", sdev->id,
  		    dev->driver ? "loaded" : "empty",
  		    dev->driver ? 1 : 0);
  	return 0;
  }

  static void snd_seq_device_info(struct snd_info_entry *entry,
  				struct snd_info_buffer *buffer)

  {

  	bus_for_each_dev(&snd_seq_bus_type, NULL, buffer, print_dev_info);

  }

  #endif

  /*
   * load all registered drivers (called from seq_clientmgr.c)
   */

  #ifdef CONFIG_MODULES

  /* flag to block auto-loading */

  static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */

  static int request_seq_drv(struct device *dev, void *data)

  {

  	struct snd_seq_device *sdev = to_seq_dev(dev);

  	if (!dev->driver)
  		request_module("snd-%s", sdev->id);
  	return 0;

  }

  static void autoload_drivers(struct work_struct *work)

  {

  	/* avoid reentrance */
  	if (atomic_inc_return(&snd_seq_in_init) == 1)
  		bus_for_each_dev(&snd_seq_bus_type, NULL, NULL,
  				 request_seq_drv);
  	atomic_dec(&snd_seq_in_init);

  }

  static DECLARE_WORK(autoload_work, autoload_drivers);

  static void queue_autoload_drivers(void)
  {

  	schedule_work(&autoload_work);

  }
  
  void snd_seq_autoload_init(void)
  {
  	atomic_dec(&snd_seq_in_init);
  #ifdef CONFIG_SND_SEQUENCER_MODULE
  	/* initial autoload only when snd-seq is a module */
  	queue_autoload_drivers();
  #endif
  }

  EXPORT_SYMBOL(snd_seq_autoload_init);

  void snd_seq_autoload_exit(void)
  {
  	atomic_inc(&snd_seq_in_init);
  }
  EXPORT_SYMBOL(snd_seq_autoload_exit);

  void snd_seq_device_load_drivers(void)
  {

  	queue_autoload_drivers();
  	flush_work(&autoload_work);

  }

  EXPORT_SYMBOL(snd_seq_device_load_drivers);

  #define cancel_autoload_drivers()	cancel_work_sync(&autoload_work)

  #else

  #define queue_autoload_drivers() /* NOP */

  #define cancel_autoload_drivers() /* NOP */

  #endif

  
  /*

   * device management
   */
  static int snd_seq_device_dev_free(struct snd_device *device)
  {
  	struct snd_seq_device *dev = device->device_data;

  	cancel_autoload_drivers();

  	put_device(&dev->dev);
  	return 0;
  }
  
  static int snd_seq_device_dev_register(struct snd_device *device)
  {
  	struct snd_seq_device *dev = device->device_data;
  	int err;
  
  	err = device_add(&dev->dev);
  	if (err < 0)
  		return err;
  	if (!dev->dev.driver)
  		queue_autoload_drivers();
  	return 0;
  }
  
  static int snd_seq_device_dev_disconnect(struct snd_device *device)
  {
  	struct snd_seq_device *dev = device->device_data;
  
  	device_del(&dev->dev);
  	return 0;
  }
  
  static void snd_seq_dev_release(struct device *dev)
  {
  	struct snd_seq_device *sdev = to_seq_dev(dev);
  
  	if (sdev->private_free)
  		sdev->private_free(sdev);
  	kfree(sdev);
  }
  
  /*

   * register a sequencer device

   * card = card info

   * device = device number (if any)
   * id = id of driver
   * result = return pointer (NULL allowed if unnecessary)
   */

  int snd_seq_device_new(struct snd_card *card, int device, const char *id,
  		       int argsize, struct snd_seq_device **result)

  {

  	struct snd_seq_device *dev;

  	int err;

  	static struct snd_device_ops dops = {

  		.dev_free = snd_seq_device_dev_free,
  		.dev_register = snd_seq_device_dev_register,
  		.dev_disconnect = snd_seq_device_dev_disconnect,

  	};
  
  	if (result)
  		*result = NULL;

  	if (snd_BUG_ON(!id))
  		return -EINVAL;

  	dev = kzalloc(sizeof(*dev) + argsize, GFP_KERNEL);
  	if (!dev)

  		return -ENOMEM;

  
  	/* set up device info */
  	dev->card = card;
  	dev->device = device;

  	dev->id = id;

  	dev->argsize = argsize;

  	device_initialize(&dev->dev);
  	dev->dev.parent = &card->card_dev;
  	dev->dev.bus = &snd_seq_bus_type;
  	dev->dev.release = snd_seq_dev_release;
  	dev_set_name(&dev->dev, "%s-%d-%d", dev->id, card->number, device);

  	/* add this device to the list */
  	err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops);
  	if (err < 0) {
  		put_device(&dev->dev);

  		return err;
  	}
  	
  	if (result)
  		*result = dev;
  
  	return 0;
  }

  EXPORT_SYMBOL(snd_seq_device_new);

  
  /*

   * driver registration

   */

  int __snd_seq_driver_register(struct snd_seq_driver *drv, struct module *mod)

  {

  	if (WARN_ON(!drv->driver.name || !drv->id))

  		return -EINVAL;

  	drv->driver.bus = &snd_seq_bus_type;
  	drv->driver.owner = mod;
  	return driver_register(&drv->driver);

  }

  EXPORT_SYMBOL_GPL(__snd_seq_driver_register);

  void snd_seq_driver_unregister(struct snd_seq_driver *drv)

  {

  	driver_unregister(&drv->driver);

  }

  EXPORT_SYMBOL_GPL(snd_seq_driver_unregister);

  
  /*
   * module part
   */

  static int __init seq_dev_proc_init(void)

  {

  #ifdef CONFIG_SND_PROC_FS

  	info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
  						  snd_seq_root);

  	if (info_entry == NULL)
  		return -ENOMEM;
  	info_entry->content = SNDRV_INFO_CONTENT_TEXT;

  	info_entry->c.text.read = snd_seq_device_info;
  	if (snd_info_register(info_entry) < 0) {
  		snd_info_free_entry(info_entry);
  		return -ENOMEM;
  	}

  #endif

  	return 0;
  }

  static int __init alsa_seq_device_init(void)
  {
  	int err;
  
  	err = bus_register(&snd_seq_bus_type);
  	if (err < 0)
  		return err;
  	err = seq_dev_proc_init();
  	if (err < 0)
  		bus_unregister(&snd_seq_bus_type);
  	return err;
  }

  static void __exit alsa_seq_device_exit(void)
  {

  #ifdef CONFIG_MODULES
  	cancel_work_sync(&autoload_work);
  #endif

  #ifdef CONFIG_SND_PROC_FS

  	snd_info_free_entry(info_entry);

  #endif

  	bus_unregister(&snd_seq_bus_type);

  }

  subsys_initcall(alsa_seq_device_init)

  module_exit(alsa_seq_device_exit)