blob: 5f75bf31bc36b6706e6408eacbd585cf0f4479c0 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
3 *
4 * Generic memory management routines for soundcard memory allocation
5 *
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.
10 *
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.
15 *
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
19 */
20
21#include <sound/driver.h>
22#include <linux/init.h>
23#include <linux/slab.h>
24#include <sound/core.h>
25#include <sound/util_mem.h>
26
27MODULE_AUTHOR("Takashi Iwai");
28MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
29MODULE_LICENSE("GPL");
30
31#define get_memblk(p) list_entry(p, snd_util_memblk_t, list)
32
33/*
34 * create a new memory manager
35 */
36snd_util_memhdr_t *
37snd_util_memhdr_new(int memsize)
38{
39 snd_util_memhdr_t *hdr;
40
Takashi Iwai561b2202005-09-09 14:22:34 +020041 hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 if (hdr == NULL)
43 return NULL;
44 hdr->size = memsize;
45 init_MUTEX(&hdr->block_mutex);
46 INIT_LIST_HEAD(&hdr->block);
47
48 return hdr;
49}
50
51/*
52 * free a memory manager
53 */
54void snd_util_memhdr_free(snd_util_memhdr_t *hdr)
55{
56 struct list_head *p;
57
58 snd_assert(hdr != NULL, return);
59 /* release all blocks */
60 while ((p = hdr->block.next) != &hdr->block) {
61 list_del(p);
62 kfree(get_memblk(p));
63 }
64 kfree(hdr);
65}
66
67/*
68 * allocate a memory block (without mutex)
69 */
70snd_util_memblk_t *
71__snd_util_mem_alloc(snd_util_memhdr_t *hdr, int size)
72{
73 snd_util_memblk_t *blk;
74 snd_util_unit_t units, prev_offset;
75 struct list_head *p;
76
77 snd_assert(hdr != NULL, return NULL);
78 snd_assert(size > 0, return NULL);
79
80 /* word alignment */
81 units = size;
82 if (units & 1)
83 units++;
84 if (units > hdr->size)
85 return NULL;
86
87 /* look for empty block */
88 prev_offset = 0;
89 list_for_each(p, &hdr->block) {
90 blk = get_memblk(p);
91 if (blk->offset - prev_offset >= units)
92 goto __found;
93 prev_offset = blk->offset + blk->size;
94 }
95 if (hdr->size - prev_offset < units)
96 return NULL;
97
98__found:
99 return __snd_util_memblk_new(hdr, units, p->prev);
100}
101
102
103/*
104 * create a new memory block with the given size
105 * the block is linked next to prev
106 */
107snd_util_memblk_t *
108__snd_util_memblk_new(snd_util_memhdr_t *hdr, snd_util_unit_t units,
109 struct list_head *prev)
110{
111 snd_util_memblk_t *blk;
112
113 blk = kmalloc(sizeof(snd_util_memblk_t) + hdr->block_extra_size, GFP_KERNEL);
114 if (blk == NULL)
115 return NULL;
116
117 if (! prev || prev == &hdr->block)
118 blk->offset = 0;
119 else {
120 snd_util_memblk_t *p = get_memblk(prev);
121 blk->offset = p->offset + p->size;
122 }
123 blk->size = units;
124 list_add(&blk->list, prev);
125 hdr->nblocks++;
126 hdr->used += units;
127 return blk;
128}
129
130
131/*
132 * allocate a memory block (with mutex)
133 */
134snd_util_memblk_t *
135snd_util_mem_alloc(snd_util_memhdr_t *hdr, int size)
136{
137 snd_util_memblk_t *blk;
138 down(&hdr->block_mutex);
139 blk = __snd_util_mem_alloc(hdr, size);
140 up(&hdr->block_mutex);
141 return blk;
142}
143
144
145/*
146 * remove the block from linked-list and free resource
147 * (without mutex)
148 */
149void
150__snd_util_mem_free(snd_util_memhdr_t *hdr, snd_util_memblk_t *blk)
151{
152 list_del(&blk->list);
153 hdr->nblocks--;
154 hdr->used -= blk->size;
155 kfree(blk);
156}
157
158/*
159 * free a memory block (with mutex)
160 */
161int snd_util_mem_free(snd_util_memhdr_t *hdr, snd_util_memblk_t *blk)
162{
163 snd_assert(hdr && blk, return -EINVAL);
164
165 down(&hdr->block_mutex);
166 __snd_util_mem_free(hdr, blk);
167 up(&hdr->block_mutex);
168 return 0;
169}
170
171/*
172 * return available memory size
173 */
174int snd_util_mem_avail(snd_util_memhdr_t *hdr)
175{
176 unsigned int size;
177 down(&hdr->block_mutex);
178 size = hdr->size - hdr->used;
179 up(&hdr->block_mutex);
180 return size;
181}
182
183
184EXPORT_SYMBOL(snd_util_memhdr_new);
185EXPORT_SYMBOL(snd_util_memhdr_free);
186EXPORT_SYMBOL(snd_util_mem_alloc);
187EXPORT_SYMBOL(snd_util_mem_free);
188EXPORT_SYMBOL(snd_util_mem_avail);
189EXPORT_SYMBOL(__snd_util_mem_alloc);
190EXPORT_SYMBOL(__snd_util_mem_free);
191EXPORT_SYMBOL(__snd_util_memblk_new);
192
193/*
194 * INIT part
195 */
196
197static int __init alsa_util_mem_init(void)
198{
199 return 0;
200}
201
202static void __exit alsa_util_mem_exit(void)
203{
204}
205
206module_init(alsa_util_mem_init)
207module_exit(alsa_util_mem_exit)