Linux 2.6.28.1
[linux/fpc-iii.git] / sound / core / sgbuf.c
blobd4564edd61d744b19fa98e6cc6a06fcd26d20b68
1 /*
2 * Scatter-Gather buffer
4 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
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.
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.
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
22 #include <linux/slab.h>
23 #include <linux/mm.h>
24 #include <linux/vmalloc.h>
25 #include <sound/memalloc.h>
28 /* table entries are align to 32 */
29 #define SGBUF_TBL_ALIGN 32
30 #define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
32 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
34 struct snd_sg_buf *sgbuf = dmab->private_data;
35 struct snd_dma_buffer tmpb;
36 int i;
38 if (! sgbuf)
39 return -EINVAL;
41 tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
42 tmpb.dev.dev = sgbuf->dev;
43 for (i = 0; i < sgbuf->pages; i++) {
44 if (!(sgbuf->table[i].addr & ~PAGE_MASK))
45 continue; /* continuous pages */
46 tmpb.area = sgbuf->table[i].buf;
47 tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
48 tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
49 snd_dma_free_pages(&tmpb);
51 if (dmab->area)
52 vunmap(dmab->area);
53 dmab->area = NULL;
55 kfree(sgbuf->table);
56 kfree(sgbuf->page_table);
57 kfree(sgbuf);
58 dmab->private_data = NULL;
60 return 0;
63 #define MAX_ALLOC_PAGES 32
65 void *snd_malloc_sgbuf_pages(struct device *device,
66 size_t size, struct snd_dma_buffer *dmab,
67 size_t *res_size)
69 struct snd_sg_buf *sgbuf;
70 unsigned int i, pages, chunk, maxpages;
71 struct snd_dma_buffer tmpb;
72 struct snd_sg_page *table;
73 struct page **pgtable;
75 dmab->area = NULL;
76 dmab->addr = 0;
77 dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
78 if (! sgbuf)
79 return NULL;
80 sgbuf->dev = device;
81 pages = snd_sgbuf_aligned_pages(size);
82 sgbuf->tblsize = sgbuf_align_table(pages);
83 table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
84 if (!table)
85 goto _failed;
86 sgbuf->table = table;
87 pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
88 if (!pgtable)
89 goto _failed;
90 sgbuf->page_table = pgtable;
92 /* allocate pages */
93 maxpages = MAX_ALLOC_PAGES;
94 while (pages > 0) {
95 chunk = pages;
96 /* don't be too eager to take a huge chunk */
97 if (chunk > maxpages)
98 chunk = maxpages;
99 chunk <<= PAGE_SHIFT;
100 if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
101 chunk, &tmpb) < 0) {
102 if (!sgbuf->pages)
103 return NULL;
104 if (!res_size)
105 goto _failed;
106 size = sgbuf->pages * PAGE_SIZE;
107 break;
109 chunk = tmpb.bytes >> PAGE_SHIFT;
110 for (i = 0; i < chunk; i++) {
111 table->buf = tmpb.area;
112 table->addr = tmpb.addr;
113 if (!i)
114 table->addr |= chunk; /* mark head */
115 table++;
116 *pgtable++ = virt_to_page(tmpb.area);
117 tmpb.area += PAGE_SIZE;
118 tmpb.addr += PAGE_SIZE;
120 sgbuf->pages += chunk;
121 pages -= chunk;
122 if (chunk < maxpages)
123 maxpages = chunk;
126 sgbuf->size = size;
127 dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
128 if (! dmab->area)
129 goto _failed;
130 if (res_size)
131 *res_size = sgbuf->size;
132 return dmab->area;
134 _failed:
135 snd_free_sgbuf_pages(dmab); /* free the table */
136 return NULL;