[linux-2.6-block.git] / sound / sound_core.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Sound core.  This file is composed of two parts.  sound_class
 *	which is common to both OSS and ALSA and OSS sound core which
 *	is used OSS or emulation of it.
 */

/*
 * First, the common part.
 */
#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <sound/core.h>

#ifdef CONFIG_SOUND_OSS_CORE
static int __init init_oss_soundcore(void);
static void cleanup_oss_soundcore(void);
#else
static inline int init_oss_soundcore(void)	{ return 0; }
static inline void cleanup_oss_soundcore(void)	{ }
#endif

struct class *sound_class;
EXPORT_SYMBOL(sound_class);

MODULE_DESCRIPTION("Core sound module");
MODULE_AUTHOR("Alan Cox");
MODULE_LICENSE("GPL");

static char *sound_devnode(struct device *dev, umode_t *mode)
{
	if (MAJOR(dev->devt) == SOUND_MAJOR)
		return NULL;
	return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev));
}

static int __init init_soundcore(void)
{
	int rc;

	rc = init_oss_soundcore();
	if (rc)
		return rc;

	sound_class = class_create(THIS_MODULE, "sound");
	if (IS_ERR(sound_class)) {
		cleanup_oss_soundcore();
		return PTR_ERR(sound_class);
	}

	sound_class->devnode = sound_devnode;

	return 0;
}

static void __exit cleanup_soundcore(void)
{
	cleanup_oss_soundcore();
	class_destroy(sound_class);
}

subsys_initcall(init_soundcore);
module_exit(cleanup_soundcore);


#ifdef CONFIG_SOUND_OSS_CORE
/*
 *	OSS sound core handling. Breaks out sound functions to submodules
 *	
 *	Author:		Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 *	Fixes:
 *
 *                         --------------------
 * 
 *	Top level handler for the sound subsystem. Various devices can
 *	plug into this. The fact they don't all go via OSS doesn't mean 
 *	they don't have to implement the OSS API. There is a lot of logic
 *	to keeping much of the OSS weight out of the code in a compatibility
 *	module, but it's up to the driver to rember to load it...
 *
 *	The code provides a set of functions for registration of devices
 *	by type. This is done rather than providing a single call so that
 *	we can hide any future changes in the internals (eg when we go to
 *	32bit dev_t) from the modules and their interface.
 *
 *	Secondly we need to allocate the dsp, dsp16 and audio devices as
 *	one. Thus we misuse the chains a bit to simplify this.
 *
 *	Thirdly to make it more fun and for 2.3.x and above we do all
 *	of this using fine grained locking.
 *
 *	FIXME: we have to resolve modules and fine grained load/unload
 *	locking at some point in 2.3.x.
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sound.h>
#include <linux/kmod.h>

#define SOUND_STEP 16

struct sound_unit
{
	int unit_minor;
	const struct file_operations *unit_fops;
	struct sound_unit *next;
	char name[32];
};

/*
 * By default, OSS sound_core claims full legacy minor range (0-255)
 * of SOUND_MAJOR to trap open attempts to any sound minor and
 * requests modules using custom sound-slot/service-* module aliases.
 * The only benefit of doing this is allowing use of custom module
 * aliases instead of the standard char-major-* ones.  This behavior
 * prevents alternative OSS implementation and is scheduled to be
 * removed.
 *
 * CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel
 * parameter are added to allow distros and developers to try and
 * switch to alternative implementations without needing to rebuild
 * the kernel in the meantime.  If preclaim_oss is non-zero, the
 * kernel will behave the same as before.  All SOUND_MAJOR minors are
 * preclaimed and the custom module aliases along with standard chrdev
 * ones are emitted if a missing device is opened.  If preclaim_oss is
 * zero, sound_core only grabs what's actually in use and for missing
 * devices only the standard chrdev aliases are requested.
 *
 * All these clutters are scheduled to be removed along with
 * sound-slot/service-* module aliases.
 */
#ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM
static int preclaim_oss = 1;
#else
static int preclaim_oss = 0;
#endif

module_param(preclaim_oss, int, 0444);

static int soundcore_open(struct inode *, struct file *);

static const struct file_operations soundcore_fops =
{
	/* We must have an owner or the module locking fails */
	.owner	= THIS_MODULE,
	.open	= soundcore_open,
	.llseek = noop_llseek,
};

/*
 *	Low level list operator. Scan the ordered list, find a hole and
 *	join into it. Called with the lock asserted
 */

static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top)
{
	int n=low;

	if (index < 0) {	/* first free */

		while (*list && (*list)->unit_minor<n)
			list=&((*list)->next);

		while(n<top)
		{
			/* Found a hole ? */
			if(*list==NULL || (*list)->unit_minor>n)
				break;
			list=&((*list)->next);
			n+=SOUND_STEP;
		}

		if(n>=top)
			return -ENOENT;
	} else {
		n = low+(index*16);
		while (*list) {
			if ((*list)->unit_minor==n)
				return -EBUSY;
			if ((*list)->unit_minor>n)
				break;
			list=&((*list)->next);
		}
	}	
		
	/*
	 *	Fill it in
	 */
	 
	s->unit_minor=n;
	s->unit_fops=fops;
	
	/*
	 *	Link it
	 */
	 
	s->next=*list;
	*list=s;
	
	
	return n;
}

/*
 *	Remove a node from the chain. Called with the lock asserted
 */
 
static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit)
{
	while(*list)
	{
		struct sound_unit *p=*list;
		if(p->unit_minor==unit)
		{
			*list=p->next;
			return p;
		}
		list=&(p->next);
	}
	printk(KERN_ERR "Sound device %d went missing!\n", unit);
	return NULL;
}

/*
 *	This lock guards the sound loader list.
 */

static DEFINE_SPINLOCK(sound_loader_lock);

/*
 *	Allocate the controlling structure and add it to the sound driver
 *	list. Acquires locks as needed
 */

static int sound_insert_unit(struct sound_unit **list, const struct file_operations *fops, int index, int low, int top, const char *name, umode_t mode, struct device *dev)
{
	struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL);
	int r;

	if (!s)
		return -ENOMEM;

	spin_lock(&sound_loader_lock);
retry:
	r = __sound_insert_unit(s, list, fops, index, low, top);
	spin_unlock(&sound_loader_lock);
	
	if (r < 0)
		goto fail;
	else if (r < SOUND_STEP)
		sprintf(s->name, "sound/%s", name);
	else
		sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP);

	if (!preclaim_oss) {
		/*
		 * Something else might have grabbed the minor.  If
		 * first free slot is requested, rescan with @low set
		 * to the next unit; otherwise, -EBUSY.
		 */
		r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name,
				      &soundcore_fops);
		if (r < 0) {
			spin_lock(&sound_loader_lock);
			__sound_remove_unit(list, s->unit_minor);
			if (index < 0) {
				low = s->unit_minor + SOUND_STEP;
				goto retry;
			}
			spin_unlock(&sound_loader_lock);
			return -EBUSY;
		}
	}

	device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
		      NULL, "%s", s->name+6);
	return s->unit_minor;

fail:
	kfree(s);
	return r;
}

/*
 *	Remove a unit. Acquires locks as needed. The drivers MUST have
 *	completed the removal before their file operations become
 *	invalid.
 */
 	
static void sound_remove_unit(struct sound_unit **list, int unit)
{
	struct sound_unit *p;

	spin_lock(&sound_loader_lock);
	p = __sound_remove_unit(list, unit);
	spin_unlock(&sound_loader_lock);
	if (p) {
		if (!preclaim_oss)
			__unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1,
					    p->name);
		device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor));
		kfree(p);
	}
}

/*
 *	Allocations
 *
 *	0	*16		Mixers
 *	1	*8		Sequencers
 *	2	*16		Midi
 *	3	*16		DSP
 *	4	*16		SunDSP
 *	5	*16		DSP16
 *	6	--		sndstat (obsolete)
 *	7	*16		unused
 *	8	--		alternate sequencer (see above)
 *	9	*16		raw synthesizer access
 *	10	*16		unused
 *	11	*16		unused
 *	12	*16		unused
 *	13	*16		unused
 *	14	*16		unused
 *	15	*16		unused
 */

static struct sound_unit *chains[SOUND_STEP];

/**
 *	register_sound_special_device - register a special sound node
 *	@fops: File operations for the driver
 *	@unit: Unit number to allocate
 *      @dev: device pointer
 *
 *	Allocate a special sound device by minor number from the sound
 *	subsystem.
 *
 *	Return: The allocated number is returned on success. On failure,
 *	a negative error code is returned.
 */
 
int register_sound_special_device(const struct file_operations *fops, int unit,
				  struct device *dev)
{
	const int chain = unit % SOUND_STEP;
	int max_unit = 256;
	const char *name;
	char _name[16];

	switch (chain) {
	    case 0:
		name = "mixer";
		break;
	    case 1:
		name = "sequencer";
		if (unit >= SOUND_STEP)
			goto __unknown;
		max_unit = unit + 1;
		break;
	    case 2:
		name = "midi";
		break;
	    case 3:
		name = "dsp";
		break;
	    case 4:
		name = "audio";
		break;
	    case 5:
		name = "dspW";
		break;
	    case 8:
		name = "sequencer2";
		if (unit >= SOUND_STEP)
			goto __unknown;
		max_unit = unit + 1;
		break;
	    case 9:
		name = "dmmidi";
		break;
	    case 10:
		name = "dmfm";
		break;
	    case 12:
		name = "adsp";
		break;
	    case 13:
		name = "amidi";
		break;
	    case 14:
		name = "admmidi";
		break;
	    default:
	    	{
		    __unknown:
			sprintf(_name, "unknown%d", chain);
		    	if (unit >= SOUND_STEP)
		    		strcat(_name, "-");
		    	name = _name;
		}
		break;
	}
	return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit,
				 name, 0600, dev);
}
 
EXPORT_SYMBOL(register_sound_special_device);

int register_sound_special(const struct file_operations *fops, int unit)
{
	return register_sound_special_device(fops, unit, NULL);
}

EXPORT_SYMBOL(register_sound_special);

/**
 *	register_sound_mixer - register a mixer device
 *	@fops: File operations for the driver
 *	@dev: Unit number to allocate
 *
 *	Allocate a mixer device. Unit is the number of the mixer requested.
 *	Pass -1 to request the next free mixer unit.
 *
 *	Return: On success, the allocated number is returned. On failure,
 *	a negative error code is returned.
 */

int register_sound_mixer(const struct file_operations *fops, int dev)
{
	return sound_insert_unit(&chains[0], fops, dev, 0, 128,
				 "mixer", 0600, NULL);
}

EXPORT_SYMBOL(register_sound_mixer);

/*
 *	DSP's are registered as a triple. Register only one and cheat
 *	in open - see below.
 */
 
/**
 *	register_sound_dsp - register a DSP device
 *	@fops: File operations for the driver
 *	@dev: Unit number to allocate
 *
 *	Allocate a DSP device. Unit is the number of the DSP requested.
 *	Pass -1 to request the next free DSP unit.
 *
 *	This function allocates both the audio and dsp device entries together
 *	and will always allocate them as a matching pair - eg dsp3/audio3
 *
 *	Return: On success, the allocated number is returned. On failure,
 *	a negative error code is returned.
 */

int register_sound_dsp(const struct file_operations *fops, int dev)
{
	return sound_insert_unit(&chains[3], fops, dev, 3, 131,
				 "dsp", 0600, NULL);
}

EXPORT_SYMBOL(register_sound_dsp);

/**
 *	unregister_sound_special - unregister a special sound device
 *	@unit: unit number to allocate
 *
 *	Release a sound device that was allocated with
 *	register_sound_special(). The unit passed is the return value from
 *	the register function.
 */


void unregister_sound_special(int unit)
{
	sound_remove_unit(&chains[unit % SOUND_STEP], unit);
}
 
EXPORT_SYMBOL(unregister_sound_special);

/**
 *	unregister_sound_mixer - unregister a mixer
 *	@unit: unit number to allocate
 *
 *	Release a sound device that was allocated with register_sound_mixer().
 *	The unit passed is the return value from the register function.
 */

void unregister_sound_mixer(int unit)
{
	sound_remove_unit(&chains[0], unit);
}

EXPORT_SYMBOL(unregister_sound_mixer);

/**
 *	unregister_sound_dsp - unregister a DSP device
 *	@unit: unit number to allocate
 *
 *	Release a sound device that was allocated with register_sound_dsp().
 *	The unit passed is the return value from the register function.
 *
 *	Both of the allocated units are released together automatically.
 */

void unregister_sound_dsp(int unit)
{
	sound_remove_unit(&chains[3], unit);
}


EXPORT_SYMBOL(unregister_sound_dsp);

static struct sound_unit *__look_for_unit(int chain, int unit)
{
	struct sound_unit *s;
	
	s=chains[chain];
	while(s && s->unit_minor <= unit)
	{
		if(s->unit_minor==unit)
			return s;
		s=s->next;
	}
	return NULL;
}

static int soundcore_open(struct inode *inode, struct file *file)
{
	int chain;
	int unit = iminor(inode);
	struct sound_unit *s;
	const struct file_operations *new_fops = NULL;

	chain=unit&0x0F;
	if(chain==4 || chain==5)	/* dsp/audio/dsp16 */
	{
		unit&=0xF0;
		unit|=3;
		chain=3;
	}
	
	spin_lock(&sound_loader_lock);
	s = __look_for_unit(chain, unit);
	if (s)
		new_fops = fops_get(s->unit_fops);
	if (preclaim_oss && !new_fops) {
		spin_unlock(&sound_loader_lock);

		/*
		 *  Please, don't change this order or code.
		 *  For ALSA slot means soundcard and OSS emulation code
		 *  comes as add-on modules which aren't depend on
		 *  ALSA toplevel modules for soundcards, thus we need
		 *  load them at first.	  [Jaroslav Kysela <perex@jcu.cz>]
		 */
		request_module("sound-slot-%i", unit>>4);
		request_module("sound-service-%i-%i", unit>>4, chain);

		/*
		 * sound-slot/service-* module aliases are scheduled
		 * for removal in favor of the standard char-major-*
		 * module aliases.  For the time being, generate both
		 * the legacy and standard module aliases to ease
		 * transition.
		 */
		if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0)
			request_module("char-major-%d", SOUND_MAJOR);

		spin_lock(&sound_loader_lock);
		s = __look_for_unit(chain, unit);
		if (s)
			new_fops = fops_get(s->unit_fops);
	}
	spin_unlock(&sound_loader_lock);
	if (new_fops) {
		/*
		 * We rely upon the fact that we can't be unloaded while the
		 * subdriver is there.
		 */
		int err = 0;
		replace_fops(file, new_fops);

		if (file->f_op->open)
			err = file->f_op->open(inode,file);

		return err;
	}
	return -ENODEV;
}

MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);

static void cleanup_oss_soundcore(void)
{
	/* We have nothing to really do here - we know the lists must be
	   empty */
	unregister_chrdev(SOUND_MAJOR, "sound");
}

static int __init init_oss_soundcore(void)
{
	if (preclaim_oss &&
	    register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) {
		printk(KERN_ERR "soundcore: sound device already in use.\n");
		return -EBUSY;
	}

	return 0;
}

#endif /* CONFIG_SOUND_OSS_CORE */
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
d886e87c TH	3	* Sound core. This file is composed of two parts. sound_class
	4	* which is common to both OSS and ALSA and OSS sound core which
	5	* is used OSS or emulation of it.
	6	*/
	7
	8	/*
	9	* First, the common part.
	10	*/
	11	#include <linux/module.h>
	12	#include <linux/device.h>
	13	#include <linux/err.h>
954a973c KS	14	#include <linux/kdev_t.h>
954a973c KS	15	#include <linux/major.h>
3d1ee379	16	#include <sound/core.h>
d886e87c TH	17
	18	#ifdef CONFIG_SOUND_OSS_CORE
	19	static int __init init_oss_soundcore(void);
de30d36b	20	static void cleanup_oss_soundcore(void);
d886e87c TH	21	#else
	22	static inline int init_oss_soundcore(void) { return 0; }
	23	static inline void cleanup_oss_soundcore(void) { }
	24	#endif
	25
	26	struct class *sound_class;
	27	EXPORT_SYMBOL(sound_class);
	28
	29	MODULE_DESCRIPTION("Core sound module");
	30	MODULE_AUTHOR("Alan Cox");
	31	MODULE_LICENSE("GPL");
	32
2c9ede55	33	static char sound_devnode(struct device dev, umode_t *mode)
7a9d56f6	34	{
954a973c KS	35	if (MAJOR(dev->devt) == SOUND_MAJOR)
954a973c KS	36	return NULL;
7a9d56f6 KS	37	return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev));
	38	}
	39
d886e87c TH	40	static int __init init_soundcore(void)
	41	{
	42	int rc;
	43
	44	rc = init_oss_soundcore();
	45	if (rc)
	46	return rc;
	47
	48	sound_class = class_create(THIS_MODULE, "sound");
	49	if (IS_ERR(sound_class)) {
	50	cleanup_oss_soundcore();
	51	return PTR_ERR(sound_class);
	52	}
	53
e454cea2	54	sound_class->devnode = sound_devnode;
7a9d56f6	55
d886e87c TH	56	return 0;
	57	}
	58
	59	static void __exit cleanup_soundcore(void)
	60	{
	61	cleanup_oss_soundcore();
	62	class_destroy(sound_class);
	63	}
	64
c181a13a	65	subsys_initcall(init_soundcore);
d886e87c TH	66	module_exit(cleanup_soundcore);
	67
	68
	69	#ifdef CONFIG_SOUND_OSS_CORE
	70	/*
	71	* OSS sound core handling. Breaks out sound functions to submodules
1da177e4	72	*
2f1e593d	73	* Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
1da177e4 LT	74	*
	75	* Fixes:
	76	*
1da177e4 LT	77	* --------------------
	78	*
	79	* Top level handler for the sound subsystem. Various devices can
	80	* plug into this. The fact they don't all go via OSS doesn't mean
	81	* they don't have to implement the OSS API. There is a lot of logic
	82	* to keeping much of the OSS weight out of the code in a compatibility
	83	* module, but it's up to the driver to rember to load it...
	84	*
	85	* The code provides a set of functions for registration of devices
	86	* by type. This is done rather than providing a single call so that
	87	* we can hide any future changes in the internals (eg when we go to
	88	* 32bit dev_t) from the modules and their interface.
	89	*
	90	* Secondly we need to allocate the dsp, dsp16 and audio devices as
	91	* one. Thus we misuse the chains a bit to simplify this.
	92	*
	93	* Thirdly to make it more fun and for 2.3.x and above we do all
	94	* of this using fine grained locking.
	95	*
	96	* FIXME: we have to resolve modules and fine grained load/unload
	97	* locking at some point in 2.3.x.
	98	*/
	99
1da177e4 LT	100	#include <linux/init.h>
	101	#include <linux/slab.h>
	102	#include <linux/types.h>
	103	#include <linux/kernel.h>
1da177e4	104	#include <linux/sound.h>
1da177e4	105	#include <linux/kmod.h>
1da177e4 LT	106
	107	#define SOUND_STEP 16
	108
1da177e4 LT	109	struct sound_unit
	110	{
	111	int unit_minor;
99ac48f5	112	const struct file_operations *unit_fops;
1da177e4 LT	113	struct sound_unit *next;
	114	char name[32];
	115	};
	116
93fe4483 TH	117	/*
	118	* By default, OSS sound_core claims full legacy minor range (0-255)
	119	* of SOUND_MAJOR to trap open attempts to any sound minor and
	120	* requests modules using custom sound-slot/service-* module aliases.
	121	* The only benefit of doing this is allowing use of custom module
	122	* aliases instead of the standard char-major-* ones. This behavior
	123	* prevents alternative OSS implementation and is scheduled to be
	124	* removed.
	125	*
	126	* CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel
	127	* parameter are added to allow distros and developers to try and
	128	* switch to alternative implementations without needing to rebuild
	129	* the kernel in the meantime. If preclaim_oss is non-zero, the
	130	* kernel will behave the same as before. All SOUND_MAJOR minors are
	131	* preclaimed and the custom module aliases along with standard chrdev
	132	* ones are emitted if a missing device is opened. If preclaim_oss is
	133	* zero, sound_core only grabs what's actually in use and for missing
	134	* devices only the standard chrdev aliases are requested.
	135	*
	136	* All these clutters are scheduled to be removed along with
8f6e6041	137	* sound-slot/service-* module aliases.
93fe4483 TH	138	*/
	139	#ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM
	140	static int preclaim_oss = 1;
	141	#else
	142	static int preclaim_oss = 0;
	143	#endif
	144
	145	module_param(preclaim_oss, int, 0444);
	146
	147	static int soundcore_open(struct inode , struct file );
	148
	149	static const struct file_operations soundcore_fops =
	150	{
	151	/* We must have an owner or the module locking fails */
	152	.owner = THIS_MODULE,
	153	.open = soundcore_open,
6038f373	154	.llseek = noop_llseek,
93fe4483 TH	155	};
93fe4483 TH	156
1da177e4 LT	157	/*
	158	* Low level list operator. Scan the ordered list, find a hole and
	159	* join into it. Called with the lock asserted
	160	*/
	161
99ac48f5	162	static int __sound_insert_unit(struct sound_unit * s, struct sound_unit *list, const struct file_operations fops, int index, int low, int top)
1da177e4 LT	163	{
	164	int n=low;
	165
	166	if (index < 0) { /* first free */
	167
	168	while (list && (list)->unit_minor<n)
	169	list=&((*list)->next);
	170
	171	while(n<top)
	172	{
	173	/* Found a hole ? */
	174	if(list==NULL \|\| (list)->unit_minor>n)
	175	break;
	176	list=&((*list)->next);
	177	n+=SOUND_STEP;
	178	}
	179
	180	if(n>=top)
	181	return -ENOENT;
	182	} else {
	183	n = low+(index*16);
	184	while (*list) {
	185	if ((*list)->unit_minor==n)
	186	return -EBUSY;
	187	if ((*list)->unit_minor>n)
	188	break;
	189	list=&((*list)->next);
	190	}
	191	}
	192
	193	/*
	194	* Fill it in
	195	*/
	196
	197	s->unit_minor=n;
	198	s->unit_fops=fops;
	199
	200	/*
	201	* Link it
	202	*/
	203
	204	s->next=*list;
	205	*list=s;
	206
	207
	208	return n;
	209	}
	210
	211	/*
	212	* Remove a node from the chain. Called with the lock asserted
	213	*/
	214
	215	static struct sound_unit __sound_remove_unit(struct sound_unit *list, int unit)
	216	{
	217	while(*list)
	218	{
	219	struct sound_unit p=list;
	220	if(p->unit_minor==unit)
	221	{
	222	*list=p->next;
	223	return p;
	224	}
	225	list=&(p->next);
	226	}
227	printk(KERN_ERR "Sound device %d went missing!\n", unit);
228	return NULL;
229	}
230
231	/*
232	* This lock guards the sound loader list.
233	*/
234
235	static DEFINE_SPINLOCK(sound_loader_lock);
236
237	/*
238	* Allocate the controlling structure and add it to the sound driver
239	* list. Acquires locks as needed
240	*/
241
99ac48f5	242	static int sound_insert_unit(struct sound_unit *list, const struct file_operations fops, int index, int low, int top, const char name, umode_t mode, struct device dev)
1da177e4 LT	243	{
	244	struct sound_unit s = kmalloc(sizeof(s), GFP_KERNEL);
	245	int r;
	246
	247	if (!s)
	248	return -ENOMEM;
93fe4483	249
1da177e4	250	spin_lock(&sound_loader_lock);
93fe4483	251	retry:
1da177e4 LT	252	r = __sound_insert_unit(s, list, fops, index, low, top);
	253	spin_unlock(&sound_loader_lock);
	254
	255	if (r < 0)
	256	goto fail;
	257	else if (r < SOUND_STEP)
	258	sprintf(s->name, "sound/%s", name);
	259	else
	260	sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP);
	261
93fe4483 TH	262	if (!preclaim_oss) {
	263	/*
	264	* Something else might have grabbed the minor. If
	265	* first free slot is requested, rescan with @low set
	266	* to the next unit; otherwise, -EBUSY.
	267	*/
	268	r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name,
	269	&soundcore_fops);
	270	if (r < 0) {
	271	spin_lock(&sound_loader_lock);
	272	__sound_remove_unit(list, s->unit_minor);
	273	if (index < 0) {
	274	low = s->unit_minor + SOUND_STEP;
	275	goto retry;
	276	}
	277	spin_unlock(&sound_loader_lock);
	278	return -EBUSY;
	279	}
	280	}
	281
abe9ab8f	282	device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
02aa2a37	283	NULL, "%s", s->name+6);
93fe4483	284	return s->unit_minor;
1da177e4	285
93fe4483	286	fail:
1da177e4 LT	287	kfree(s);
	288	return r;
	289	}
	290
	291	/*
	292	* Remove a unit. Acquires locks as needed. The drivers MUST have
	293	* completed the removal before their file operations become
	294	* invalid.
	295	*/
	296
	297	static void sound_remove_unit(struct sound_unit **list, int unit)
	298	{
	299	struct sound_unit *p;
	300
	301	spin_lock(&sound_loader_lock);
	302	p = __sound_remove_unit(list, unit);
	303	spin_unlock(&sound_loader_lock);
	304	if (p) {
93fe4483 TH	305	if (!preclaim_oss)
	306	__unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1,
	307	p->name);
d80f19fa	308	device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor));
1da177e4 LT	309	kfree(p);
	310	}
	311	}
	312
	313	/*
	314	* Allocations
	315	*
	316	* 0 *16 Mixers
	317	* 1 *8 Sequencers
	318	* 2 *16 Midi
	319	* 3 *16 DSP
	320	* 4 *16 SunDSP
	321	* 5 *16 DSP16
	322	* 6 -- sndstat (obsolete)
	323	* 7 *16 unused
	324	* 8 -- alternate sequencer (see above)
	325	* 9 *16 raw synthesizer access
	326	* 10 *16 unused
	327	* 11 *16 unused
	328	* 12 *16 unused
	329	* 13 *16 unused
	330	* 14 *16 unused
	331	* 15 *16 unused
	332	*/
	333
	334	static struct sound_unit *chains[SOUND_STEP];
	335
	336	/**
d568121c	337	* register_sound_special_device - register a special sound node
1da177e4 LT	338	* @fops: File operations for the driver
1da177e4 LT	339	* @unit: Unit number to allocate
d568121c	340	* @dev: device pointer
1da177e4 LT	341	*
1da177e4 LT	342	* Allocate a special sound device by minor number from the sound
eb7c06e8 YB	343	* subsystem.
	344	*
	345	* Return: The allocated number is returned on success. On failure,
1da177e4 LT	346	* a negative error code is returned.
	347	*/
	348
99ac48f5	349	int register_sound_special_device(const struct file_operations *fops, int unit,
d568121c	350	struct device *dev)
1da177e4 LT	351	{
1da177e4 LT	352	const int chain = unit % SOUND_STEP;
2abb8017	353	int max_unit = 256;
1da177e4 LT	354	const char *name;
	355	char _name[16];
	356
	357	switch (chain) {
	358	case 0:
	359	name = "mixer";
	360	break;
	361	case 1:
	362	name = "sequencer";
	363	if (unit >= SOUND_STEP)
	364	goto __unknown;
	365	max_unit = unit + 1;
	366	break;
	367	case 2:
	368	name = "midi";
	369	break;
	370	case 3:
	371	name = "dsp";
	372	break;
	373	case 4:
	374	name = "audio";
	375	break;
848669da TI	376	case 5:
	377	name = "dspW";
	378	break;
1da177e4 LT	379	case 8:
	380	name = "sequencer2";
	381	if (unit >= SOUND_STEP)
	382	goto __unknown;
	383	max_unit = unit + 1;
	384	break;
	385	case 9:
	386	name = "dmmidi";
	387	break;
	388	case 10:
	389	name = "dmfm";
	390	break;
	391	case 12:
	392	name = "adsp";
	393	break;
	394	case 13:
	395	name = "amidi";
	396	break;
	397	case 14:
	398	name = "admmidi";
	399	break;
	400	default:
	401	{
	402	__unknown:
	403	sprintf(_name, "unknown%d", chain);
	404	if (unit >= SOUND_STEP)
	405	strcat(_name, "-");
	406	name = _name;
	407	}
	408	break;
	409	}
	410	return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit,
6a73cf46	411	name, 0600, dev);
1da177e4 LT	412	}
1da177e4 LT	413
d568121c TI	414	EXPORT_SYMBOL(register_sound_special_device);
d568121c TI	415
99ac48f5	416	int register_sound_special(const struct file_operations *fops, int unit)
d568121c TI	417	{
	418	return register_sound_special_device(fops, unit, NULL);
	419	}
	420
1da177e4 LT	421	EXPORT_SYMBOL(register_sound_special);
	422
	423	/**
	424	* register_sound_mixer - register a mixer device
	425	* @fops: File operations for the driver
	426	* @dev: Unit number to allocate
	427	*
	428	* Allocate a mixer device. Unit is the number of the mixer requested.
eb7c06e8 YB	429	* Pass -1 to request the next free mixer unit.
	430	*
	431	* Return: On success, the allocated number is returned. On failure,
	432	* a negative error code is returned.
1da177e4 LT	433	*/
1da177e4 LT	434
99ac48f5	435	int register_sound_mixer(const struct file_operations *fops, int dev)
1da177e4 LT	436	{
1da177e4 LT	437	return sound_insert_unit(&chains[0], fops, dev, 0, 128,
6a73cf46	438	"mixer", 0600, NULL);
1da177e4 LT	439	}
	440
	441	EXPORT_SYMBOL(register_sound_mixer);
	442
1da177e4 LT	443	/*
	444	* DSP's are registered as a triple. Register only one and cheat
	445	* in open - see below.
	446	*/
	447
	448	/**
	449	* register_sound_dsp - register a DSP device
	450	* @fops: File operations for the driver
	451	* @dev: Unit number to allocate
	452	*
	453	* Allocate a DSP device. Unit is the number of the DSP requested.
eb7c06e8	454	* Pass -1 to request the next free DSP unit.
1da177e4 LT	455	*
	456	* This function allocates both the audio and dsp device entries together
	457	* and will always allocate them as a matching pair - eg dsp3/audio3
eb7c06e8 YB	458	*
	459	* Return: On success, the allocated number is returned. On failure,
	460	* a negative error code is returned.
1da177e4 LT	461	*/
1da177e4 LT	462
99ac48f5	463	int register_sound_dsp(const struct file_operations *fops, int dev)
1da177e4 LT	464	{
1da177e4 LT	465	return sound_insert_unit(&chains[3], fops, dev, 3, 131,
6a73cf46	466	"dsp", 0600, NULL);
1da177e4 LT	467	}
	468
	469	EXPORT_SYMBOL(register_sound_dsp);
	470
1da177e4 LT	471	/**
	472	* unregister_sound_special - unregister a special sound device
	473	* @unit: unit number to allocate
	474	*
	475	* Release a sound device that was allocated with
	476	* register_sound_special(). The unit passed is the return value from
	477	* the register function.
	478	*/
	479
	480
	481	void unregister_sound_special(int unit)
	482	{
	483	sound_remove_unit(&chains[unit % SOUND_STEP], unit);
	484	}
	485
	486	EXPORT_SYMBOL(unregister_sound_special);
	487
	488	/**
	489	* unregister_sound_mixer - unregister a mixer
	490	* @unit: unit number to allocate
	491	*
	492	* Release a sound device that was allocated with register_sound_mixer().
	493	* The unit passed is the return value from the register function.
	494	*/
	495
	496	void unregister_sound_mixer(int unit)
	497	{
	498	sound_remove_unit(&chains[0], unit);
	499	}
	500
	501	EXPORT_SYMBOL(unregister_sound_mixer);
	502
1da177e4 LT	503	/**
	504	* unregister_sound_dsp - unregister a DSP device
	505	* @unit: unit number to allocate
	506	*
	507	* Release a sound device that was allocated with register_sound_dsp().
	508	* The unit passed is the return value from the register function.
	509	*
	510	* Both of the allocated units are released together automatically.
	511	*/
	512
	513	void unregister_sound_dsp(int unit)
	514	{
a39c4ad1	515	sound_remove_unit(&chains[3], unit);
1da177e4 LT	516	}
	517
	518
	519	EXPORT_SYMBOL(unregister_sound_dsp);
	520
1da177e4 LT	521	static struct sound_unit *__look_for_unit(int chain, int unit)
	522	{
	523	struct sound_unit *s;
	524
	525	s=chains[chain];
	526	while(s && s->unit_minor <= unit)
	527	{
	528	if(s->unit_minor==unit)
	529	return s;
	530	s=s->next;
	531	}
	532	return NULL;
	533	}
	534
a39c4ad1	535	static int soundcore_open(struct inode inode, struct file file)
1da177e4 LT	536	{
	537	int chain;
	538	int unit = iminor(inode);
	539	struct sound_unit *s;
99ac48f5	540	const struct file_operations *new_fops = NULL;
1da177e4 LT	541
	542	chain=unit&0x0F;
	543	if(chain==4 \|\| chain==5) /* dsp/audio/dsp16 */
	544	{
	545	unit&=0xF0;
	546	unit\|=3;
	547	chain=3;
	548	}
	549
	550	spin_lock(&sound_loader_lock);
	551	s = __look_for_unit(chain, unit);
	552	if (s)
	553	new_fops = fops_get(s->unit_fops);
93fe4483	554	if (preclaim_oss && !new_fops) {
1da177e4	555	spin_unlock(&sound_loader_lock);
0a848680	556
1da177e4 LT	557	/*
	558	* Please, don't change this order or code.
	559	* For ALSA slot means soundcard and OSS emulation code
	560	* comes as add-on modules which aren't depend on
	561	* ALSA toplevel modules for soundcards, thus we need
	562	* load them at first. [Jaroslav Kysela <perex@jcu.cz>]
	563	*/
	564	request_module("sound-slot-%i", unit>>4);
	565	request_module("sound-service-%i-%i", unit>>4, chain);
0a848680 TH	566
	567	/*
	568	* sound-slot/service-* module aliases are scheduled
	569	* for removal in favor of the standard char-major-*
	570	* module aliases. For the time being, generate both
	571	* the legacy and standard module aliases to ease
	572	* transition.
	573	*/
	574	if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0)
	575	request_module("char-major-%d", SOUND_MAJOR);
	576
1da177e4 LT	577	spin_lock(&sound_loader_lock);
	578	s = __look_for_unit(chain, unit);
	579	if (s)
	580	new_fops = fops_get(s->unit_fops);
	581	}
e84f9e57	582	spin_unlock(&sound_loader_lock);
1da177e4 LT	583	if (new_fops) {
	584	/*
	585	* We rely upon the fact that we can't be unloaded while the
e84f9e57	586	* subdriver is there.
1da177e4 LT	587	*/
1da177e4 LT	588	int err = 0;
e84f9e57	589	replace_fops(file, new_fops);
171d9f7d	590
90dc763f	591	if (file->f_op->open)
1da177e4	592	err = file->f_op->open(inode,file);
171d9f7d	593
1da177e4 LT	594	return err;
1da177e4 LT	595	}
1da177e4 LT	596	return -ENODEV;
	597	}
	598
1da177e4 LT	599	MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
1da177e4 LT	600
de30d36b	601	static void cleanup_oss_soundcore(void)
1da177e4 LT	602	{
	603	/* We have nothing to really do here - we know the lists must be
	604	empty */
	605	unregister_chrdev(SOUND_MAJOR, "sound");
1da177e4 LT	606	}
1da177e4 LT	607
d886e87c	608	static int __init init_oss_soundcore(void)
1da177e4	609	{
93fe4483	610	if (preclaim_oss &&
cb68429d	611	register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) {
1da177e4 LT	612	printk(KERN_ERR "soundcore: sound device already in use.\n");
	613	return -EBUSY;
	614	}
1da177e4 LT	615
	616	return 0;
	617	}
	618
d886e87c	619	#endif /* CONFIG_SOUND_OSS_CORE */