1 /*
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 <linux/mutex.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <sound/core.h>
25 #include <sound/util_mem.h>
26
27 MODULE_AUTHOR("Takashi Iwai");
28 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
29 MODULE_LICENSE("GPL");
30
31 #define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
32
33 /*
34 * create a new memory manager
35 */
36 struct snd_util_memhdr *
37 snd_util_memhdr_new(int memsize)
38 {
39 struct snd_util_memhdr *hdr;
40
41 hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
42 if (hdr == NULL)
43 return NULL;
44 hdr->size = memsize;
45 mutex_init(&hdr->block_mutex);
46 INIT_LIST_HEAD(&hdr->block);
47
48 return hdr;
49 }
50
51 /*
52 * free a memory manager
53 */
54 void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
55 {
56 struct list_head *p;
57
58 if (!hdr)
59 return;
60 /* release all blocks */
61 while ((p = hdr->block.next) != &hdr->block) {
62 list_del(p);
63 kfree(get_memblk(p));
64 }
65 kfree(hdr);
66 }
67
68 /*
69 * allocate a memory block (without mutex)
70 */
71 struct snd_util_memblk *
72 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
73 {
74 struct snd_util_memblk *blk;
75 unsigned int units, prev_offset;
76 struct list_head *p;
77
78 if (snd_BUG_ON(!hdr || size <= 0))
79 return NULL;
80
81 /* word alignment */
82 units = size;
83 if (units & 1)
84 units++;
85 if (units > hdr->size)
86 return NULL;
87
88 /* look for empty block */
89 prev_offset = 0;
90 list_for_each(p, &hdr->block) {
91 blk = get_memblk(p);
92 if (blk->offset - prev_offset >= units)
93 goto __found;
94 prev_offset = blk->offset + blk->size;
95 }
96 if (hdr->size - prev_offset < units)
97 return NULL;
98
99 __found:
100 return __snd_util_memblk_new(hdr, units, p->prev);
101 }
102
103
104 /*
105 * create a new memory block with the given size
106 * the block is linked next to prev
107 */
108 struct snd_util_memblk *
109 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
110 struct list_head *prev)
111 {
112 struct snd_util_memblk *blk;
113
114 blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
115 GFP_KERNEL);
116 if (blk == NULL)
117 return NULL;
118
119 if (prev == &hdr->block)
120 blk->offset = 0;
121 else {
122 struct snd_util_memblk *p = get_memblk(prev);
123 blk->offset = p->offset + p->size;
124 }
125 blk->size = units;
126 list_add(&blk->list, prev);
127 hdr->nblocks++;
128 hdr->used += units;
129 return blk;
130 }
131
132
133 /*
134 * allocate a memory block (with mutex)
135 */
136 struct snd_util_memblk *
137 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
138 {
139 struct snd_util_memblk *blk;
140 mutex_lock(&hdr->block_mutex);
141 blk = __snd_util_mem_alloc(hdr, size);
142 mutex_unlock(&hdr->block_mutex);
143 return blk;
144 }
145
146
147 /*
148 * remove the block from linked-list and free resource
149 * (without mutex)
150 */
151 void
152 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
153 {
154 list_del(&blk->list);
155 hdr->nblocks--;
156 hdr->used -= blk->size;
157 kfree(blk);
158 }
159
160 /*
161 * free a memory block (with mutex)
162 */
163 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
164 {
165 if (snd_BUG_ON(!hdr || !blk))
166 return -EINVAL;
167
168 mutex_lock(&hdr->block_mutex);
169 __snd_util_mem_free(hdr, blk);
170 mutex_unlock(&hdr->block_mutex);
171 return 0;
172 }
173
174 /*
175 * return available memory size
176 */
177 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
178 {
179 unsigned int size;
180 mutex_lock(&hdr->block_mutex);
181 size = hdr->size - hdr->used;
182 mutex_unlock(&hdr->block_mutex);
183 return size;
184 }
185
186
187 EXPORT_SYMBOL(snd_util_memhdr_new);
188 EXPORT_SYMBOL(snd_util_memhdr_free);
189 EXPORT_SYMBOL(snd_util_mem_alloc);
190 EXPORT_SYMBOL(snd_util_mem_free);
191 EXPORT_SYMBOL(snd_util_mem_avail);
192 EXPORT_SYMBOL(__snd_util_mem_alloc);
193 EXPORT_SYMBOL(__snd_util_mem_free);
194 EXPORT_SYMBOL(__snd_util_memblk_new);
195
196 /*
197 * INIT part
198 */
199
200 static int __init alsa_util_mem_init(void)
201 {
202 return 0;
203 }
204
205 static void __exit alsa_util_mem_exit(void)
206 {
207 }
208
209 module_init(alsa_util_mem_init)
210 module_exit(alsa_util_mem_exit)
211
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