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 <linux/export.h>
26 #include <sound/memalloc.h>
27
28
29 /* table entries are align to 32 */
30 #define SGBUF_TBL_ALIGN 32
31 #define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
32
snd_free_sgbuf_pages(struct snd_dma_buffer * dmab)33 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
34 {
35 struct snd_sg_buf *sgbuf = dmab->private_data;
36 struct snd_dma_buffer tmpb;
37 int i;
38
39 if (! sgbuf)
40 return -EINVAL;
41
42 vunmap(dmab->area);
43 dmab->area = NULL;
44
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);
54 }
55
56 kfree(sgbuf->table);
57 kfree(sgbuf->page_table);
58 kfree(sgbuf);
59 dmab->private_data = NULL;
60
61 return 0;
62 }
63
64 #define MAX_ALLOC_PAGES 32
65
snd_malloc_sgbuf_pages(struct device * device,size_t size,struct snd_dma_buffer * dmab,size_t * res_size)66 void *snd_malloc_sgbuf_pages(struct device *device,
67 size_t size, struct snd_dma_buffer *dmab,
68 size_t *res_size)
69 {
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;
75
76 dmab->area = NULL;
77 dmab->addr = 0;
78 dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
79 if (! sgbuf)
80 return NULL;
81 sgbuf->dev = device;
82 pages = snd_sgbuf_aligned_pages(size);
83 sgbuf->tblsize = sgbuf_align_table(pages);
84 table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
85 if (!table)
86 goto _failed;
87 sgbuf->table = table;
88 pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
89 if (!pgtable)
90 goto _failed;
91 sgbuf->page_table = pgtable;
92
93 /* allocate pages */
94 maxpages = MAX_ALLOC_PAGES;
95 while (pages > 0) {
96 chunk = pages;
97 /* don't be too eager to take a huge chunk */
98 if (chunk > maxpages)
99 chunk = maxpages;
100 chunk <<= PAGE_SHIFT;
101 if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
102 chunk, &tmpb) < 0) {
103 if (!sgbuf->pages)
104 goto _failed;
105 if (!res_size)
106 goto _failed;
107 size = sgbuf->pages * PAGE_SIZE;
108 break;
109 }
110 chunk = tmpb.bytes >> PAGE_SHIFT;
111 for (i = 0; i < chunk; i++) {
112 table->buf = tmpb.area;
113 table->addr = tmpb.addr;
114 if (!i)
115 table->addr |= chunk; /* mark head */
116 table++;
117 *pgtable++ = virt_to_page(tmpb.area);
118 tmpb.area += PAGE_SIZE;
119 tmpb.addr += PAGE_SIZE;
120 }
121 sgbuf->pages += chunk;
122 pages -= chunk;
123 if (chunk < maxpages)
124 maxpages = chunk;
125 }
126
127 sgbuf->size = size;
128 dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
129 if (! dmab->area)
130 goto _failed;
131 if (res_size)
132 *res_size = sgbuf->size;
133 return dmab->area;
134
135 _failed:
136 snd_free_sgbuf_pages(dmab); /* free the table */
137 return NULL;
138 }
139
140 /*
141 * compute the max chunk size with continuous pages on sg-buffer
142 */
snd_sgbuf_get_chunk_size(struct snd_dma_buffer * dmab,unsigned int ofs,unsigned int size)143 unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
144 unsigned int ofs, unsigned int size)
145 {
146 struct snd_sg_buf *sg = dmab->private_data;
147 unsigned int start, end, pg;
148
149 start = ofs >> PAGE_SHIFT;
150 end = (ofs + size - 1) >> PAGE_SHIFT;
151 /* check page continuity */
152 pg = sg->table[start].addr >> PAGE_SHIFT;
153 for (;;) {
154 start++;
155 if (start > end)
156 break;
157 pg++;
158 if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
159 return (start << PAGE_SHIFT) - ofs;
160 }
161 /* ok, all on continuous pages */
162 return size;
163 }
164 EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
165
