[linux-block.git] / sound / core / seq / seq_device.c

/*
 *  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 <sound/driver.h>
#include <linux/init.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>

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

/* driver state */
#define DRIVER_EMPTY		0
#define DRIVER_LOADED		(1<<0)
#define DRIVER_REQUESTED	(1<<1)
#define DRIVER_LOCKED		(1<<2)

struct ops_list {
	char id[ID_LEN];	/* driver id */
	int driver;		/* driver state */
	int used;		/* reference counter */
	int argsize;		/* argument size */

	/* operators */
	struct snd_seq_dev_ops ops;

	/* registred devices */
	struct list_head dev_list;	/* list of devices */
	int num_devices;	/* number of associated devices */
	int num_init_devices;	/* number of initialized devices */
	struct semaphore reg_mutex;

	struct list_head list;	/* next driver */
};


static LIST_HEAD(opslist);
static int num_ops;
static DECLARE_MUTEX(ops_mutex);
#ifdef CONFIG_PROC_FS
static struct snd_info_entry *info_entry = NULL;
#endif

/*
 * prototypes
 */
static int snd_seq_device_free(struct snd_seq_device *dev);
static int snd_seq_device_dev_free(struct snd_device *device);
static int snd_seq_device_dev_register(struct snd_device *device);
static int snd_seq_device_dev_disconnect(struct snd_device *device);
static int snd_seq_device_dev_unregister(struct snd_device *device);

static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
static struct ops_list *find_driver(char *id, int create_if_empty);
static struct ops_list *create_driver(char *id);
static void unlock_driver(struct ops_list *ops);
static void remove_drivers(void);

/*
 * show all drivers and their status
 */

#ifdef CONFIG_PROC_FS
static void snd_seq_device_info(struct snd_info_entry *entry,
				struct snd_info_buffer *buffer)
{
	struct list_head *head;

	down(&ops_mutex);
	list_for_each(head, &opslist) {
		struct ops_list *ops = list_entry(head, struct ops_list, list);
		snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
				ops->id,
				ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
				ops->driver & DRIVER_REQUESTED ? ",requested" : "",
				ops->driver & DRIVER_LOCKED ? ",locked" : "",
				ops->num_devices);
	}
	up(&ops_mutex);	
}
#endif
 
/*
 * load all registered drivers (called from seq_clientmgr.c)
 */

#ifdef CONFIG_KMOD
/* avoid auto-loading during module_init() */
static int snd_seq_in_init;
void snd_seq_autoload_lock(void)
{
	snd_seq_in_init++;
}

void snd_seq_autoload_unlock(void)
{
	snd_seq_in_init--;
}
#endif

void snd_seq_device_load_drivers(void)
{
#ifdef CONFIG_KMOD
	struct list_head *head;

	/* Calling request_module during module_init()
	 * may cause blocking.
	 */
	if (snd_seq_in_init)
		return;

	if (! current->fs->root)
		return;

	down(&ops_mutex);
	list_for_each(head, &opslist) {
		struct ops_list *ops = list_entry(head, struct ops_list, list);
		if (! (ops->driver & DRIVER_LOADED) &&
		    ! (ops->driver & DRIVER_REQUESTED)) {
			ops->used++;
			up(&ops_mutex);
			ops->driver |= DRIVER_REQUESTED;
			request_module("snd-%s", ops->id);
			down(&ops_mutex);
			ops->used--;
		}
	}
	up(&ops_mutex);
#endif
}

/*
 * register a sequencer device
 * card = card info (NULL allowed)
 * 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, char *id, int argsize,
		       struct snd_seq_device **result)
{
	struct snd_seq_device *dev;
	struct ops_list *ops;
	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,
		.dev_unregister = snd_seq_device_dev_unregister
	};

	if (result)
		*result = NULL;

	snd_assert(id != NULL, return -EINVAL);

	ops = find_driver(id, 1);
	if (ops == NULL)
		return -ENOMEM;

	dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
	if (dev == NULL) {
		unlock_driver(ops);
		return -ENOMEM;
	}

	/* set up device info */
	dev->card = card;
	dev->device = device;
	strlcpy(dev->id, id, sizeof(dev->id));
	dev->argsize = argsize;
	dev->status = SNDRV_SEQ_DEVICE_FREE;

	/* add this device to the list */
	down(&ops->reg_mutex);
	list_add_tail(&dev->list, &ops->dev_list);
	ops->num_devices++;
	up(&ops->reg_mutex);

	unlock_driver(ops);
	
	if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
		snd_seq_device_free(dev);
		return err;
	}
	
	if (result)
		*result = dev;

	return 0;
}

/*
 * free the existing device
 */
static int snd_seq_device_free(struct snd_seq_device *dev)
{
	struct ops_list *ops;

	snd_assert(dev != NULL, return -EINVAL);

	ops = find_driver(dev->id, 0);
	if (ops == NULL)
		return -ENXIO;

	/* remove the device from the list */
	down(&ops->reg_mutex);
	list_del(&dev->list);
	ops->num_devices--;
	up(&ops->reg_mutex);

	free_device(dev, ops);
	if (dev->private_free)
		dev->private_free(dev);
	kfree(dev);

	unlock_driver(ops);

	return 0;
}

static int snd_seq_device_dev_free(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;
	return snd_seq_device_free(dev);
}

/*
 * register the device
 */
static int snd_seq_device_dev_register(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;
	struct ops_list *ops;

	ops = find_driver(dev->id, 0);
	if (ops == NULL)
		return -ENOENT;

	/* initialize this device if the corresponding driver was
	 * already loaded
	 */
	if (ops->driver & DRIVER_LOADED)
		init_device(dev, ops);

	unlock_driver(ops);
	return 0;
}

/*
 * disconnect the device
 */
static int snd_seq_device_dev_disconnect(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;
	struct ops_list *ops;

	ops = find_driver(dev->id, 0);
	if (ops == NULL)
		return -ENOENT;

	free_device(dev, ops);

	unlock_driver(ops);
	return 0;
}

/*
 * unregister the existing device
 */
static int snd_seq_device_dev_unregister(struct snd_device *device)
{
	struct snd_seq_device *dev = device->device_data;
	return snd_seq_device_free(dev);
}

/*
 * register device driver
 * id = driver id
 * entry = driver operators - duplicated to each instance
 */
int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
				   int argsize)
{
	struct list_head *head;
	struct ops_list *ops;

	if (id == NULL || entry == NULL ||
	    entry->init_device == NULL || entry->free_device == NULL)
		return -EINVAL;

	snd_seq_autoload_lock();
	ops = find_driver(id, 1);
	if (ops == NULL) {
		snd_seq_autoload_unlock();
		return -ENOMEM;
	}
	if (ops->driver & DRIVER_LOADED) {
		snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
		unlock_driver(ops);
		snd_seq_autoload_unlock();
		return -EBUSY;
	}

	down(&ops->reg_mutex);
	/* copy driver operators */
	ops->ops = *entry;
	ops->driver |= DRIVER_LOADED;
	ops->argsize = argsize;

	/* initialize existing devices if necessary */
	list_for_each(head, &ops->dev_list) {
		struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
		init_device(dev, ops);
	}
	up(&ops->reg_mutex);

	unlock_driver(ops);
	snd_seq_autoload_unlock();

	return 0;
}


/*
 * create driver record
 */
static struct ops_list * create_driver(char *id)
{
	struct ops_list *ops;

	ops = kmalloc(sizeof(*ops), GFP_KERNEL);
	if (ops == NULL)
		return ops;
	memset(ops, 0, sizeof(*ops));

	/* set up driver entry */
	strlcpy(ops->id, id, sizeof(ops->id));
	init_MUTEX(&ops->reg_mutex);
	ops->driver = DRIVER_EMPTY;
	INIT_LIST_HEAD(&ops->dev_list);
	/* lock this instance */
	ops->used = 1;

	/* register driver entry */
	down(&ops_mutex);
	list_add_tail(&ops->list, &opslist);
	num_ops++;
	up(&ops_mutex);

	return ops;
}


/*
 * unregister the specified driver
 */
int snd_seq_device_unregister_driver(char *id)
{
	struct list_head *head;
	struct ops_list *ops;

	ops = find_driver(id, 0);
	if (ops == NULL)
		return -ENXIO;
	if (! (ops->driver & DRIVER_LOADED) ||
	    (ops->driver & DRIVER_LOCKED)) {
		snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
			   id, ops->driver);
		unlock_driver(ops);
		return -EBUSY;
	}

	/* close and release all devices associated with this driver */
	down(&ops->reg_mutex);
	ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
	list_for_each(head, &ops->dev_list) {
		struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
		free_device(dev, ops);
	}

	ops->driver = 0;
	if (ops->num_init_devices > 0)
		snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
			   ops->num_init_devices);
	up(&ops->reg_mutex);

	unlock_driver(ops);

	/* remove empty driver entries */
	remove_drivers();

	return 0;
}


/*
 * remove empty driver entries
 */
static void remove_drivers(void)
{
	struct list_head *head;

	down(&ops_mutex);
	head = opslist.next;
	while (head != &opslist) {
		struct ops_list *ops = list_entry(head, struct ops_list, list);
		if (! (ops->driver & DRIVER_LOADED) &&
		    ops->used == 0 && ops->num_devices == 0) {
			head = head->next;
			list_del(&ops->list);
			kfree(ops);
			num_ops--;
		} else
			head = head->next;
	}
	up(&ops_mutex);
}

/*
 * initialize the device - call init_device operator
 */
static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
{
	if (! (ops->driver & DRIVER_LOADED))
		return 0; /* driver is not loaded yet */
	if (dev->status != SNDRV_SEQ_DEVICE_FREE)
		return 0; /* already initialized */
	if (ops->argsize != dev->argsize) {
		snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
			   dev->name, ops->id, ops->argsize, dev->argsize);
		return -EINVAL;
	}
	if (ops->ops.init_device(dev) >= 0) {
		dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
		ops->num_init_devices++;
	} else {
		snd_printk(KERN_ERR "init_device failed: %s: %s\n",
			   dev->name, dev->id);
	}

	return 0;
}

/*
 * release the device - call free_device operator
 */
static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
{
	int result;

	if (! (ops->driver & DRIVER_LOADED))
		return 0; /* driver is not loaded yet */
	if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
		return 0; /* not registered */
	if (ops->argsize != dev->argsize) {
		snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
			   dev->name, ops->id, ops->argsize, dev->argsize);
		return -EINVAL;
	}
	if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
		dev->status = SNDRV_SEQ_DEVICE_FREE;
		dev->driver_data = NULL;
		ops->num_init_devices--;
	} else {
		snd_printk(KERN_ERR "free_device failed: %s: %s\n",
			   dev->name, dev->id);
	}

	return 0;
}

/*
 * find the matching driver with given id
 */
static struct ops_list * find_driver(char *id, int create_if_empty)
{
	struct list_head *head;

	down(&ops_mutex);
	list_for_each(head, &opslist) {
		struct ops_list *ops = list_entry(head, struct ops_list, list);
		if (strcmp(ops->id, id) == 0) {
			ops->used++;
			up(&ops_mutex);
			return ops;
		}
	}
	up(&ops_mutex);
	if (create_if_empty)
		return create_driver(id);
	return NULL;
}

static void unlock_driver(struct ops_list *ops)
{
	down(&ops_mutex);
	ops->used--;
	up(&ops_mutex);
}


/*
 * module part
 */

static int __init alsa_seq_device_init(void)
{
#ifdef CONFIG_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_size = 2048;
	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 void __exit alsa_seq_device_exit(void)
{
	remove_drivers();
#ifdef CONFIG_PROC_FS
	snd_info_unregister(info_entry);
#endif
	if (num_ops)
		snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
}

module_init(alsa_seq_device_init)
module_exit(alsa_seq_device_exit)

EXPORT_SYMBOL(snd_seq_device_load_drivers);
EXPORT_SYMBOL(snd_seq_device_new);
EXPORT_SYMBOL(snd_seq_device_register_driver);
EXPORT_SYMBOL(snd_seq_device_unregister_driver);
#ifdef CONFIG_KMOD
EXPORT_SYMBOL(snd_seq_autoload_lock);
EXPORT_SYMBOL(snd_seq_autoload_unlock);
#endif
Commit	Line	Data
1da177e4 LT	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
1da177e4 LT	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 */
c7e0b5bf	66	struct snd_seq_dev_ops ops;
1da177e4 LT	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);
04f141a8	81	#ifdef CONFIG_PROC_FS
c7e0b5bf	82	static struct snd_info_entry *info_entry = NULL;
04f141a8	83	#endif
1da177e4 LT	84
	85	/*
	86	* prototypes
	87	*/
c7e0b5bf TI	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);
1da177e4 LT	99	static void remove_drivers(void);
	100
	101	/*
	102	* show all drivers and their status
	103	*/
	104
04f141a8	105	#ifdef CONFIG_PROC_FS
c7e0b5bf TI	106	static void snd_seq_device_info(struct snd_info_entry *entry,
c7e0b5bf TI	107	struct snd_info_buffer *buffer)
1da177e4 LT	108	{
	109	struct list_head *head;
	110
	111	down(&ops_mutex);
	112	list_for_each(head, &opslist) {
c7e0b5bf	113	struct ops_list *ops = list_entry(head, struct ops_list, list);
1da177e4 LT	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	}
04f141a8	123	#endif
1da177e4 LT	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) {
c7e0b5bf	159	struct ops_list *ops = list_entry(head, struct ops_list, list);
1da177e4 LT	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	*/
c7e0b5bf TI	181	int snd_seq_device_new(struct snd_card card, int device, char id, int argsize,
c7e0b5bf TI	182	struct snd_seq_device **result)
1da177e4	183	{
c7e0b5bf TI	184	struct snd_seq_device *dev;
c7e0b5bf TI	185	struct ops_list *ops;
1da177e4	186	int err;
c7e0b5bf	187	static struct snd_device_ops dops = {
1da177e4 LT	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
ecca82b4	203	dev = kzalloc(sizeof(dev)2 + argsize, GFP_KERNEL);
1da177e4 LT	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	*/
c7e0b5bf	238	static int snd_seq_device_free(struct snd_seq_device *dev)
1da177e4	239	{
c7e0b5bf	240	struct ops_list *ops;
1da177e4 LT	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
c7e0b5bf	264	static int snd_seq_device_dev_free(struct snd_device *device)
1da177e4	265	{
c7e0b5bf	266	struct snd_seq_device *dev = device->device_data;
1da177e4 LT	267	return snd_seq_device_free(dev);
	268	}
	269
	270	/*
	271	* register the device
	272	*/
c7e0b5bf	273	static int snd_seq_device_dev_register(struct snd_device *device)
1da177e4	274	{
c7e0b5bf TI	275	struct snd_seq_device *dev = device->device_data;
c7e0b5bf TI	276	struct ops_list *ops;
1da177e4 LT	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	*/
c7e0b5bf	295	static int snd_seq_device_dev_disconnect(struct snd_device *device)
1da177e4	296	{
c7e0b5bf TI	297	struct snd_seq_device *dev = device->device_data;
c7e0b5bf TI	298	struct ops_list *ops;
1da177e4 LT	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	*/
c7e0b5bf	313	static int snd_seq_device_dev_unregister(struct snd_device *device)
1da177e4	314	{
c7e0b5bf	315	struct snd_seq_device *dev = device->device_data;
1da177e4 LT	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	*/
c7e0b5bf TI	324	int snd_seq_device_register_driver(char id, struct snd_seq_dev_ops entry,
c7e0b5bf TI	325	int argsize)
1da177e4 LT	326	{
1da177e4 LT	327	struct list_head *head;
c7e0b5bf	328	struct ops_list *ops;
1da177e4 LT	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) {
c7e0b5bf	355	struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
1da177e4 LT	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	*/
c7e0b5bf	370	static struct ops_list * create_driver(char *id)
1da177e4	371	{
c7e0b5bf	372	struct ops_list *ops;
1da177e4 LT	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;
c7e0b5bf	403	struct ops_list *ops;
1da177e4 LT	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)) {
c7e0b5bf TI	410	snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
c7e0b5bf TI	411	id, ops->driver);
1da177e4 LT	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) {
c7e0b5bf	420	struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, list);
1da177e4 LT	421	free_device(dev, ops);
	422	}
	423
	424	ops->driver = 0;
	425	if (ops->num_init_devices > 0)
c7e0b5bf TI	426	snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
c7e0b5bf TI	427	ops->num_init_devices);
1da177e4 LT	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) {
c7e0b5bf	449	struct ops_list *ops = list_entry(head, struct ops_list, list);
1da177e4 LT	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	*/
c7e0b5bf	465	static int init_device(struct snd_seq_device dev, struct ops_list ops)
1da177e4 LT	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) {
c7e0b5bf TI	472	snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
c7e0b5bf TI	473	dev->name, ops->id, ops->argsize, dev->argsize);
1da177e4 LT	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 {
c7e0b5bf TI	480	snd_printk(KERN_ERR "init_device failed: %s: %s\n",
c7e0b5bf TI	481	dev->name, dev->id);
1da177e4 LT	482	}
	483
	484	return 0;
	485	}
	486
	487	/*
	488	* release the device - call free_device operator
	489	*/
c7e0b5bf	490	static int free_device(struct snd_seq_device dev, struct ops_list ops)
1da177e4 LT	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) {
c7e0b5bf TI	499	snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
c7e0b5bf TI	500	dev->name, ops->id, ops->argsize, dev->argsize);
1da177e4 LT	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 {
c7e0b5bf TI	508	snd_printk(KERN_ERR "free_device failed: %s: %s\n",
c7e0b5bf TI	509	dev->name, dev->id);
1da177e4 LT	510	}
	511
	512	return 0;
	513	}
	514
	515	/*
	516	* find the matching driver with given id
	517	*/
c7e0b5bf	518	static struct ops_list * find_driver(char *id, int create_if_empty)
1da177e4 LT	519	{
	520	struct list_head *head;
	521
	522	down(&ops_mutex);
	523	list_for_each(head, &opslist) {
c7e0b5bf	524	struct ops_list *ops = list_entry(head, struct ops_list, list);
1da177e4 LT	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
c7e0b5bf	537	static void unlock_driver(struct ops_list *ops)
1da177e4 LT	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	{
04f141a8	551	#ifdef CONFIG_PROC_FS
c7e0b5bf TI	552	info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
c7e0b5bf TI	553	snd_seq_root);
1da177e4 LT	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	}
04f141a8	563	#endif
1da177e4 LT	564	return 0;
	565	}
	566
	567	static void __exit alsa_seq_device_exit(void)
	568	{
	569	remove_drivers();
04f141a8	570	#ifdef CONFIG_PROC_FS
1da177e4	571	snd_info_unregister(info_entry);
04f141a8	572	#endif
1da177e4 LT	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