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 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 */
70 struct snd_util_memblk *
71 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
72 {
73 struct snd_util_memblk *blk;
74 unsigned int 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 */
107 struct snd_util_memblk *
108 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
109 struct list_head *prev)
110 {
111 struct snd_util_memblk *blk;
112
113 blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
114 GFP_KERNEL);
115 if (blk == NULL)
116 return NULL;
117
118 if (prev == &hdr->block)
119 blk->offset = 0;
120 else {
121 struct snd_util_memblk *p = get_memblk(prev);
122 blk->offset = p->offset + p->size;
123 }
124 blk->size = units;
125 list_add(&blk->list, prev);
126 hdr->nblocks++;
127 hdr->used += units;
128 return blk;
129 }
130
131
132 /*
133 * allocate a memory block (with mutex)
134 */
135 struct snd_util_memblk *
136 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
137 {
138 struct snd_util_memblk *blk;
139 mutex_lock(&hdr->block_mutex);
140 blk = __snd_util_mem_alloc(hdr, size);
141 mutex_unlock(&hdr->block_mutex);
142 return blk;
143 }
144
145
146 /*
147 * remove the block from linked-list and free resource
148 * (without mutex)
149 */
150 void
151 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
152 {
153 list_del(&blk->list);
154 hdr->nblocks--;
155 hdr->used -= blk->size;
156 kfree(blk);
157 }
158
159 /*
160 * free a memory block (with mutex)
161 */
162 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
163 {
164 snd_assert(hdr && blk, return -EINVAL);
165
166 mutex_lock(&hdr->block_mutex);
167 __snd_util_mem_free(hdr, blk);
168 mutex_unlock(&hdr->block_mutex);
169 return 0;
170 }
171
172 /*
173 * return available memory size
174 */
175 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
176 {
177 unsigned int size;
178 mutex_lock(&hdr->block_mutex);
179 size = hdr->size - hdr->used;
180 mutex_unlock(&hdr->block_mutex);
181 return size;
182 }
183
184
185 EXPORT_SYMBOL(snd_util_memhdr_new);
186 EXPORT_SYMBOL(snd_util_memhdr_free);
187 EXPORT_SYMBOL(snd_util_mem_alloc);
188 EXPORT_SYMBOL(snd_util_mem_free);
189 EXPORT_SYMBOL(snd_util_mem_avail);
190 EXPORT_SYMBOL(__snd_util_mem_alloc);
191 EXPORT_SYMBOL(__snd_util_mem_free);
192 EXPORT_SYMBOL(__snd_util_memblk_new);
193
194 /*
195 * INIT part
196 */
197
198 static int __init alsa_util_mem_init(void)
199 {
200 return 0;
201 }
202
203 static void __exit alsa_util_mem_exit(void)
204 {
205 }
206
207 module_init(alsa_util_mem_init)
208 module_exit(alsa_util_mem_exit)
209
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