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 <linux/module.h>
25 #include <sound/core.h>
26 #include <sound/util_mem.h>
27
28 MODULE_AUTHOR("Takashi Iwai");
29 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
30 MODULE_LICENSE("GPL");
31
32 #define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
33
34 /*
35 * create a new memory manager
36 */
37 struct snd_util_memhdr *
snd_util_memhdr_new(int memsize)38 snd_util_memhdr_new(int memsize)
39 {
40 struct snd_util_memhdr *hdr;
41
42 hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
43 if (hdr == NULL)
44 return NULL;
45 hdr->size = memsize;
46 mutex_init(&hdr->block_mutex);
47 INIT_LIST_HEAD(&hdr->block);
48
49 return hdr;
50 }
51
52 /*
53 * free a memory manager
54 */
snd_util_memhdr_free(struct snd_util_memhdr * hdr)55 void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
56 {
57 struct list_head *p;
58
59 if (!hdr)
60 return;
61 /* release all blocks */
62 while ((p = hdr->block.next) != &hdr->block) {
63 list_del(p);
64 kfree(get_memblk(p));
65 }
66 kfree(hdr);
67 }
68
69 /*
70 * allocate a memory block (without mutex)
71 */
72 struct snd_util_memblk *
__snd_util_mem_alloc(struct snd_util_memhdr * hdr,int size)73 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
74 {
75 struct snd_util_memblk *blk;
76 unsigned int units, prev_offset;
77 struct list_head *p;
78
79 if (snd_BUG_ON(!hdr || size <= 0))
80 return NULL;
81
82 /* word alignment */
83 units = size;
84 if (units & 1)
85 units++;
86 if (units > hdr->size)
87 return NULL;
88
89 /* look for empty block */
90 prev_offset = 0;
91 list_for_each(p, &hdr->block) {
92 blk = get_memblk(p);
93 if (blk->offset - prev_offset >= units)
94 goto __found;
95 prev_offset = blk->offset + blk->size;
96 }
97 if (hdr->size - prev_offset < units)
98 return NULL;
99
100 __found:
101 return __snd_util_memblk_new(hdr, units, p->prev);
102 }
103
104
105 /*
106 * create a new memory block with the given size
107 * the block is linked next to prev
108 */
109 struct snd_util_memblk *
__snd_util_memblk_new(struct snd_util_memhdr * hdr,unsigned int units,struct list_head * prev)110 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
111 struct list_head *prev)
112 {
113 struct snd_util_memblk *blk;
114
115 blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
116 GFP_KERNEL);
117 if (blk == NULL)
118 return NULL;
119
120 if (prev == &hdr->block)
121 blk->offset = 0;
122 else {
123 struct snd_util_memblk *p = get_memblk(prev);
124 blk->offset = p->offset + p->size;
125 }
126 blk->size = units;
127 list_add(&blk->list, prev);
128 hdr->nblocks++;
129 hdr->used += units;
130 return blk;
131 }
132
133
134 /*
135 * allocate a memory block (with mutex)
136 */
137 struct snd_util_memblk *
snd_util_mem_alloc(struct snd_util_memhdr * hdr,int size)138 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
139 {
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);
144 return blk;
145 }
146
147
148 /*
149 * remove the block from linked-list and free resource
150 * (without mutex)
151 */
152 void
__snd_util_mem_free(struct snd_util_memhdr * hdr,struct snd_util_memblk * blk)153 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
154 {
155 list_del(&blk->list);
156 hdr->nblocks--;
157 hdr->used -= blk->size;
158 kfree(blk);
159 }
160
161 /*
162 * free a memory block (with mutex)
163 */
snd_util_mem_free(struct snd_util_memhdr * hdr,struct snd_util_memblk * blk)164 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
165 {
166 if (snd_BUG_ON(!hdr || !blk))
167 return -EINVAL;
168
169 mutex_lock(&hdr->block_mutex);
170 __snd_util_mem_free(hdr, blk);
171 mutex_unlock(&hdr->block_mutex);
172 return 0;
173 }
174
175 /*
176 * return available memory size
177 */
snd_util_mem_avail(struct snd_util_memhdr * hdr)178 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
179 {
180 unsigned int size;
181 mutex_lock(&hdr->block_mutex);
182 size = hdr->size - hdr->used;
183 mutex_unlock(&hdr->block_mutex);
184 return size;
185 }
186
187
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);
196
197 /*
198 * INIT part
199 */
200
alsa_util_mem_init(void)201 static int __init alsa_util_mem_init(void)
202 {
203 return 0;
204 }
205
alsa_util_mem_exit(void)206 static void __exit alsa_util_mem_exit(void)
207 {
208 }
209
210 module_init(alsa_util_mem_init)
211 module_exit(alsa_util_mem_exit)
212