Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>

 *

 *  Generic memory management routines for soundcard memory allocation

 *

 *   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

 */

#include <linux/mutex.h>

#include <sound/driver.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <sound/core.h>

#include <sound/util_mem.h>

MODULE_AUTHOR("Takashi Iwai");

MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");

MODULE_LICENSE("GPL");

#define get_memblk(p)   list_entry(p, struct snd_util_memblk, list)

/*

 * create a new memory manager

 */

struct snd_util_memhdr *

snd_util_memhdr_new(int memsize)

{

        struct snd_util_memhdr *hdr;

        hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);

        if (hdr == NULL)

                return NULL;

        hdr->size = memsize;

        mutex_init(&hdr->block_mutex);

        INIT_LIST_HEAD(&hdr->block);

        return hdr;

}

/*

 * free a memory manager

 */

void snd_util_memhdr_free(struct snd_util_memhdr *hdr)

{

        struct list_head *p;

        snd_assert(hdr != NULL, return);

        /* release all blocks */

        while ((p = hdr->block.next) != &hdr->block) {

                list_del(p);

                kfree(get_memblk(p));

        }

        kfree(hdr);

}

/*

 * allocate a memory block (without mutex)

 */

struct snd_util_memblk *

__snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)

{

        struct snd_util_memblk *blk;

        unsigned int units, prev_offset;

        struct list_head *p;

        snd_assert(hdr != NULL, return NULL);

        snd_assert(size > 0, return NULL);

        /* word alignment */

        units = size;

        if (units & 1)

                units++;

        if (units > hdr->size)

                return NULL;

        /* look for empty block */

        prev_offset = 0;

        list_for_each(p, &hdr->block) {

                blk = get_memblk(p);

                if (blk->offset - prev_offset >= units)

                        goto __found;

                prev_offset = blk->offset + blk->size;

        }

        if (hdr->size - prev_offset < units)

                return NULL;

__found:

        return __snd_util_memblk_new(hdr, units, p->prev);

}

/*

 * create a new memory block with the given size

 * the block is linked next to prev

 */

struct snd_util_memblk *

__snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,

                      struct list_head *prev)

{

        struct snd_util_memblk *blk;

        blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,

                      GFP_KERNEL);

        if (blk == NULL)

                return NULL;

        if (prev == &hdr->block)

                blk->offset = 0;

        else {

                struct snd_util_memblk *p = get_memblk(prev);

                blk->offset = p->offset + p->size;

        }

        blk->size = units;

        list_add(&blk->list, prev);

        hdr->nblocks++;

        hdr->used += units;

        return blk;

}

/*

 * allocate a memory block (with mutex)

 */

struct snd_util_memblk *

snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)

{

        struct snd_util_memblk *blk;

        mutex_lock(&hdr->block_mutex);

        blk = __snd_util_mem_alloc(hdr, size);

        mutex_unlock(&hdr->block_mutex);

        return blk;

}

/*

 * remove the block from linked-list and free resource

 * (without mutex)

 */

void

__snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)

{

        list_del(&blk->list);

        hdr->nblocks--;

        hdr->used -= blk->size;

        kfree(blk);

}

/*

 * free a memory block (with mutex)

 */

int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)

{

        snd_assert(hdr && blk, return -EINVAL);

        mutex_lock(&hdr->block_mutex);

        __snd_util_mem_free(hdr, blk);

        mutex_unlock(&hdr->block_mutex);

        return 0;

}

/*

 * return available memory size

 */

int snd_util_mem_avail(struct snd_util_memhdr *hdr)

{

        unsigned int size;

        mutex_lock(&hdr->block_mutex);

        size = hdr->size - hdr->used;

        mutex_unlock(&hdr->block_mutex);

        return size;

}

EXPORT_SYMBOL(snd_util_memhdr_new);

EXPORT_SYMBOL(snd_util_memhdr_free);

EXPORT_SYMBOL(snd_util_mem_alloc);

EXPORT_SYMBOL(snd_util_mem_free);

EXPORT_SYMBOL(snd_util_mem_avail);

EXPORT_SYMBOL(__snd_util_mem_alloc);

EXPORT_SYMBOL(__snd_util_mem_free);

EXPORT_SYMBOL(__snd_util_memblk_new);

/*

 *  INIT part

 */

static int __init alsa_util_mem_init(void)

{

        return 0;

}

static void __exit alsa_util_mem_exit(void)

{

}

module_init(alsa_util_mem_init)

module_exit(alsa_util_mem_exit)