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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - sound/core/sgbuf.c
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>
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
;
45 tmpb
.dev
.type
= SNDRV_DMA_TYPE_DEV
;
46 tmpb
.dev
.dev
= sgbuf
->dev
;
47 for (i
= 0; i
< sgbuf
->pages
; i
++) {
48 if (!(sgbuf
->table
[i
].addr
& ~PAGE_MASK
))
49 continue; /* continuous pages */
50 tmpb
.area
= sgbuf
->table
[i
].buf
;
51 tmpb
.addr
= sgbuf
->table
[i
].addr
& PAGE_MASK
;
52 tmpb
.bytes
= (sgbuf
->table
[i
].addr
& ~PAGE_MASK
) << PAGE_SHIFT
;
53 snd_dma_free_pages(&tmpb
);
57 kfree(sgbuf
->page_table
);
59 dmab
->private_data
= NULL
;
64 #define MAX_ALLOC_PAGES 32
66 void *snd_malloc_sgbuf_pages(struct device
*device
,
67 size_t size
, struct snd_dma_buffer
*dmab
,
70 struct snd_sg_buf
*sgbuf
;
71 unsigned int i
, pages
, chunk
, maxpages
;
72 struct snd_dma_buffer tmpb
;
73 struct snd_sg_page
*table
;
74 struct page
**pgtable
;
78 dmab
->private_data
= sgbuf
= kzalloc(sizeof(*sgbuf
), GFP_KERNEL
);
82 pages
= snd_sgbuf_aligned_pages(size
);
83 sgbuf
->tblsize
= sgbuf_align_table(pages
);
84 table
= kcalloc(sgbuf
->tblsize
, sizeof(*table
), GFP_KERNEL
);
88 pgtable
= kcalloc(sgbuf
->tblsize
, sizeof(*pgtable
), GFP_KERNEL
);
91 sgbuf
->page_table
= pgtable
;
94 maxpages
= MAX_ALLOC_PAGES
;
97 /* don't be too eager to take a huge chunk */
100 chunk
<<= PAGE_SHIFT
;
101 if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV
, device
,
107 size
= sgbuf
->pages
* PAGE_SIZE
;
110 chunk
= tmpb
.bytes
>> PAGE_SHIFT
;
111 for (i
= 0; i
< chunk
; i
++) {
112 table
->buf
= tmpb
.area
;
113 table
->addr
= tmpb
.addr
;
115 table
->addr
|= chunk
; /* mark head */
117 *pgtable
++ = virt_to_page(tmpb
.area
);
118 tmpb
.area
+= PAGE_SIZE
;
119 tmpb
.addr
+= PAGE_SIZE
;
121 sgbuf
->pages
+= chunk
;
123 if (chunk
< maxpages
)
128 dmab
->area
= vmap(sgbuf
->page_table
, sgbuf
->pages
, VM_MAP
, PAGE_KERNEL
);
132 *res_size
= sgbuf
->size
;
136 snd_free_sgbuf_pages(dmab
); /* free the table */