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2 * Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
4 * Generic memory management routines for soundcard memory allocation
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/mutex.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <sound/core.h>
26 #include <sound/util_mem.h>
28 MODULE_AUTHOR("Takashi Iwai");
29 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
30 MODULE_LICENSE("GPL");
32 #define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
35 * create a new memory manager
37 struct snd_util_memhdr
*
38 snd_util_memhdr_new(int memsize
)
40 struct snd_util_memhdr
*hdr
;
42 hdr
= kzalloc(sizeof(*hdr
), GFP_KERNEL
);
46 mutex_init(&hdr
->block_mutex
);
47 INIT_LIST_HEAD(&hdr
->block
);
53 * free a memory manager
55 void snd_util_memhdr_free(struct snd_util_memhdr
*hdr
)
61 /* release all blocks */
62 while ((p
= hdr
->block
.next
) != &hdr
->block
) {
70 * allocate a memory block (without mutex)
72 struct snd_util_memblk
*
73 __snd_util_mem_alloc(struct snd_util_memhdr
*hdr
, int size
)
75 struct snd_util_memblk
*blk
;
76 unsigned int units
, prev_offset
;
79 if (snd_BUG_ON(!hdr
|| size
<= 0))
86 if (units
> hdr
->size
)
89 /* look for empty block */
91 list_for_each(p
, &hdr
->block
) {
93 if (blk
->offset
- prev_offset
>= units
)
95 prev_offset
= blk
->offset
+ blk
->size
;
97 if (hdr
->size
- prev_offset
< units
)
101 return __snd_util_memblk_new(hdr
, units
, p
->prev
);
106 * create a new memory block with the given size
107 * the block is linked next to prev
109 struct snd_util_memblk
*
110 __snd_util_memblk_new(struct snd_util_memhdr
*hdr
, unsigned int units
,
111 struct list_head
*prev
)
113 struct snd_util_memblk
*blk
;
115 blk
= kmalloc(sizeof(struct snd_util_memblk
) + hdr
->block_extra_size
,
120 if (prev
== &hdr
->block
)
123 struct snd_util_memblk
*p
= get_memblk(prev
);
124 blk
->offset
= p
->offset
+ p
->size
;
127 list_add(&blk
->list
, prev
);
135 * allocate a memory block (with mutex)
137 struct snd_util_memblk
*
138 snd_util_mem_alloc(struct snd_util_memhdr
*hdr
, int size
)
140 struct snd_util_memblk
*blk
;
141 mutex_lock(&hdr
->block_mutex
);
142 blk
= __snd_util_mem_alloc(hdr
, size
);
143 mutex_unlock(&hdr
->block_mutex
);
149 * remove the block from linked-list and free resource
153 __snd_util_mem_free(struct snd_util_memhdr
*hdr
, struct snd_util_memblk
*blk
)
155 list_del(&blk
->list
);
157 hdr
->used
-= blk
->size
;
162 * free a memory block (with mutex)
164 int snd_util_mem_free(struct snd_util_memhdr
*hdr
, struct snd_util_memblk
*blk
)
166 if (snd_BUG_ON(!hdr
|| !blk
))
169 mutex_lock(&hdr
->block_mutex
);
170 __snd_util_mem_free(hdr
, blk
);
171 mutex_unlock(&hdr
->block_mutex
);
176 * return available memory size
178 int snd_util_mem_avail(struct snd_util_memhdr
*hdr
)
181 mutex_lock(&hdr
->block_mutex
);
182 size
= hdr
->size
- hdr
->used
;
183 mutex_unlock(&hdr
->block_mutex
);
188 EXPORT_SYMBOL(snd_util_memhdr_new
);
189 EXPORT_SYMBOL(snd_util_memhdr_free
);
190 EXPORT_SYMBOL(snd_util_mem_alloc
);
191 EXPORT_SYMBOL(snd_util_mem_free
);
192 EXPORT_SYMBOL(snd_util_mem_avail
);
193 EXPORT_SYMBOL(__snd_util_mem_alloc
);
194 EXPORT_SYMBOL(__snd_util_mem_free
);
195 EXPORT_SYMBOL(__snd_util_memblk_new
);
201 static int __init
alsa_util_mem_init(void)
206 static void __exit
alsa_util_mem_exit(void)
210 module_init(alsa_util_mem_init
)
211 module_exit(alsa_util_mem_exit
)