/*
* Sound core handling. Breaks out sound functions to submodules
*
* Author: Alan Cox <alan.cox@linux.org>
*
* Fixes:
*
*
* 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.
*
* --------------------
*
* 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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/sound.h>
#include <linux/major.h>
#include <linux/kmod.h>
#include <linux/device.h>
#define SOUND_STEP 16
struct sound_unit
{
int unit_minor;
const struct file_operations *unit_fops;
struct sound_unit *next;
char name[32];
};
#ifdef CONFIG_SOUND_MSNDCLAS
extern int msnd_classic_init(void);
#endif
#ifdef CONFIG_SOUND_MSNDPIN
extern int msnd_pinnacle_init(void);
#endif
struct class *sound_class;
EXPORT_SYMBOL(sound_class);
/*
* 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);
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);
device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
s->name+6);
return r;
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) {
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. The allocated number is returned on succes. 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 = 128 + chain;
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 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, S_IRUSR | S_IWUSR, 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. 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", S_IRUSR | S_IWUSR, NULL);
}
EXPORT_SYMBOL(register_sound_mixer);
/**
* register_sound_midi - register a midi device
* @fops: File operations for the driver
* @dev: Unit number to allocate
*
* Allocate a midi device. Unit is the number of the midi device requested.
* Pass -1 to request the next free midi unit. On success the allocated
* number is returned, on failure a negative error code is returned.
*/
int register_sound_midi(const struct file_operations *fops, int dev)
{
return sound_insert_unit(&chains[2], fops, dev, 2, 130,
"midi", S_IRUSR | S_IWUSR, NULL);
}
EXPORT_SYMBOL(register_sound_midi);
/*
* 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. On success the allocated
* number is returned, on failure a negative error code is returned.
*
* This function allocates both the audio and dsp device entries together
* and will always allocate them as a matching pair - eg dsp3/audio3
*/
int register_sound_dsp(const struct file_operations *fops, int dev)
{
return sound_insert_unit(&chains[3], fops, dev, 3, 131,
"dsp", S_IWUSR | S_IRUSR, 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_midi - unregister a midi device
* @unit: unit number to allocate
*
* Release a sound device that was allocated with register_sound_midi().
* The unit passed is the return value from the register function.
*/
void unregister_sound_midi(int unit)
{
return sound_remove_unit(&chains[2], unit);
}
EXPORT_SYMBOL(unregister_sound_midi);
/**
* 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)
{
return sound_remove_unit(&chains[3], unit);
}
EXPORT_SYMBOL(unregister_sound_dsp);
/*
* Now our file operations
*/
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,
};
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;
}
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 (!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);
spin_lock(&sound_loader_lock);
s = __look_for_unit(chain, unit);
if (s)
new_fops = fops_get(s->unit_fops);
}
if (new_fops) {
/*
* We rely upon the fact that we can't be unloaded while the
* subdriver is there, so if ->open() is successful we can
* safely drop the reference counter and if it is not we can
* revert to old ->f_op. Ugly, indeed, but that's the cost of
* switching ->f_op in the first place.
*/
int err = 0;
const struct file_operations *old_fops = file->f_op;
file->f_op = new_fops;
spin_unlock(&sound_loader_lock);
if(file->f_op->open)
err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
return err;
}
spin_unlock(&sound_loader_lock);
return -ENODEV;
}
MODULE_DESCRIPTION("Core sound module");
MODULE_AUTHOR("Alan Cox");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
static void __exit cleanup_soundcore(void)
{
/* We have nothing to really do here - we know the lists must be
empty */
unregister_chrdev(SOUND_MAJOR, "sound");
class_destroy(sound_class);
}
static int __init init_soundcore(void)
{
if (register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops)==-1) {
printk(KERN_ERR "soundcore: sound device already in use.\n");
return -EBUSY;
}
sound_class = class_create(THIS_MODULE, "sound");
if (IS_ERR(sound_class))
return PTR_ERR(sound_class);
return 0;
}
module_init(init_soundcore);
module_exit(cleanup_soundcore);
