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1da177e4 LT |
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 <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 | ||
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, snd_util_memblk_t, list) | |
32 | ||
33 | /* | |
34 | * create a new memory manager | |
35 | */ | |
36 | snd_util_memhdr_t * | |
37 | snd_util_memhdr_new(int memsize) | |
38 | { | |
39 | snd_util_memhdr_t *hdr; | |
40 | ||
41 | hdr = kcalloc(1, sizeof(*hdr), GFP_KERNEL); | |
42 | 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 | */ | |
54 | void 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 | */ | |
70 | snd_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 | */ | |
107 | snd_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 | */ | |
134 | snd_util_memblk_t * | |
135 | snd_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 | */ | |
149 | void | |
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 | */ | |
161 | int 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 | */ | |
174 | int 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 | ||
184 | EXPORT_SYMBOL(snd_util_memhdr_new); | |
185 | EXPORT_SYMBOL(snd_util_memhdr_free); | |
186 | EXPORT_SYMBOL(snd_util_mem_alloc); | |
187 | EXPORT_SYMBOL(snd_util_mem_free); | |
188 | EXPORT_SYMBOL(snd_util_mem_avail); | |
189 | EXPORT_SYMBOL(__snd_util_mem_alloc); | |
190 | EXPORT_SYMBOL(__snd_util_mem_free); | |
191 | EXPORT_SYMBOL(__snd_util_memblk_new); | |
192 | ||
193 | /* | |
194 | * INIT part | |
195 | */ | |
196 | ||
197 | static int __init alsa_util_mem_init(void) | |
198 | { | |
199 | return 0; | |
200 | } | |
201 | ||
202 | static void __exit alsa_util_mem_exit(void) | |
203 | { | |
204 | } | |
205 | ||
206 | module_init(alsa_util_mem_init) | |
207 | module_exit(alsa_util_mem_exit) |