d4564edd61d744b19fa98e6cc6a06fcd26d20b68
[linux-2.6.git] / sound / core / sgbuf.c
1 /*
2  * Scatter-Gather buffer
3  *
4  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
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
22 #include <linux/slab.h>
23 #include <linux/mm.h>
24 #include <linux/vmalloc.h>
25 #include <sound/memalloc.h>
26
27
28 /* table entries are align to 32 */
29 #define SGBUF_TBL_ALIGN         32
30 #define sgbuf_align_table(tbl)  ALIGN((tbl), SGBUF_TBL_ALIGN)
31
32 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
33 {
34         struct snd_sg_buf *sgbuf = dmab->private_data;
35         struct snd_dma_buffer tmpb;
36         int i;
37
38         if (! sgbuf)
39                 return -EINVAL;
40
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);
50         }
51         if (dmab->area)
52                 vunmap(dmab->area);
53         dmab->area = NULL;
54
55         kfree(sgbuf->table);
56         kfree(sgbuf->page_table);
57         kfree(sgbuf);
58         dmab->private_data = NULL;
59         
60         return 0;
61 }
62
63 #define MAX_ALLOC_PAGES         32
64
65 void *snd_malloc_sgbuf_pages(struct device *device,
66                              size_t size, struct snd_dma_buffer *dmab,
67                              size_t *res_size)
68 {
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;
74
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;
91
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;
108                 }
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;
119                 }
120                 sgbuf->pages += chunk;
121                 pages -= chunk;
122                 if (chunk < maxpages)
123                         maxpages = chunk;
124         }
125
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;
133
134  _failed:
135         snd_free_sgbuf_pages(dmab); /* free the table */
136         return NULL;
137 }