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 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 * 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 */ 55 void 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 */ 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 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 */ 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 || 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 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 */ 176 int 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 } 184 185 186 EXPORT_SYMBOL(snd_util_memhdr_new); 187 EXPORT_SYMBOL(snd_util_memhdr_free); 188 EXPORT_SYMBOL(snd_util_mem_alloc); 189 EXPORT_SYMBOL(snd_util_mem_free); 190 EXPORT_SYMBOL(snd_util_mem_avail); 191 EXPORT_SYMBOL(__snd_util_mem_alloc); 192 EXPORT_SYMBOL(__snd_util_mem_free); 193 EXPORT_SYMBOL(__snd_util_memblk_new); 194 195 /* 196 * INIT part 197 */ 198 199 static int __init alsa_util_mem_init(void) 200 { 201 return 0; 202 } 203 204 static void __exit alsa_util_mem_exit(void) 205 { 206 } 207 208 module_init(alsa_util_mem_init) 209 module_exit(alsa_util_mem_exit) 210