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 <sound/driver.h>
23#include <linux/init.h>
24#include <linux/slab.h>
25#include <sound/core.h>
26#include <sound/util_mem.h>
27
28MODULE_AUTHOR("Takashi Iwai");
29MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
30MODULE_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 */
37struct snd_util_memhdr *
38snd_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 */
55void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
56{
57	struct list_head *p;
58
59	snd_assert(hdr != NULL, 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 */
71struct 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	snd_assert(hdr != NULL, return NULL);
79	snd_assert(size > 0, 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 */
108struct 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 || 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 */
136struct snd_util_memblk *
137snd_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 */
151void
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 */
163int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
164{
165	snd_assert(hdr && blk, return -EINVAL);
166
167	mutex_lock(&hdr->block_mutex);
168	__snd_util_mem_free(hdr, blk);
169	mutex_unlock(&hdr->block_mutex);
170	return 0;
171}
172
173/*
174 * return available memory size
175 */
176int snd_util_mem_avail(struct snd_util_memhdr *hdr)
177{
178	unsigned int size;
179	mutex_lock(&hdr->block_mutex);
180	size = hdr->size - hdr->used;
181	mutex_unlock(&hdr->block_mutex);
182	return size;
183}
184
185
186EXPORT_SYMBOL(snd_util_memhdr_new);
187EXPORT_SYMBOL(snd_util_memhdr_free);
188EXPORT_SYMBOL(snd_util_mem_alloc);
189EXPORT_SYMBOL(snd_util_mem_free);
190EXPORT_SYMBOL(snd_util_mem_avail);
191EXPORT_SYMBOL(__snd_util_mem_alloc);
192EXPORT_SYMBOL(__snd_util_mem_free);
193EXPORT_SYMBOL(__snd_util_memblk_new);
194
195/*
196 *  INIT part
197 */
198
199static int __init alsa_util_mem_init(void)
200{
201	return 0;
202}
203
204static void __exit alsa_util_mem_exit(void)
205{
206}
207
208module_init(alsa_util_mem_init)
209module_exit(alsa_util_mem_exit)
210