Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *      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);