tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Scatter-Gather buffer
4 *
5 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
6 */
7
8#include <linux/slab.h>
9#include <linux/mm.h>
10#include <linux/vmalloc.h>
11#include <linux/export.h>
12#include <asm/pgtable.h>
13#include <sound/memalloc.h>
14
15
16/* table entries are align to 32 */
17#define SGBUF_TBL_ALIGN 32
18#define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
19
20int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
21{
22 struct snd_sg_buf *sgbuf = dmab->private_data;
23 struct snd_dma_buffer tmpb;
24 int i;
25
26 if (! sgbuf)
27 return -EINVAL;
28
29 vunmap(dmab->area);
30 dmab->area = NULL;
31
32 tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
33 if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG)
34 tmpb.dev.type = SNDRV_DMA_TYPE_DEV_UC;
35 tmpb.dev.dev = sgbuf->dev;
36 for (i = 0; i < sgbuf->pages; i++) {
37 if (!(sgbuf->table[i].addr & ~PAGE_MASK))
38 continue; /* continuous pages */
39 tmpb.area = sgbuf->table[i].buf;
40 tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
41 tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
42 snd_dma_free_pages(&tmpb);
43 }
44
45 kfree(sgbuf->table);
46 kfree(sgbuf->page_table);
47 kfree(sgbuf);
48 dmab->private_data = NULL;
49
50 return 0;
51}
52
53#define MAX_ALLOC_PAGES 32
54
55void *snd_malloc_sgbuf_pages(struct device *device,
56 size_t size, struct snd_dma_buffer *dmab,
57 size_t *res_size)
58{
59 struct snd_sg_buf *sgbuf;
60 unsigned int i, pages, chunk, maxpages;
61 struct snd_dma_buffer tmpb;
62 struct snd_sg_page *table;
63 struct page **pgtable;
64 int type = SNDRV_DMA_TYPE_DEV;
65 pgprot_t prot = PAGE_KERNEL;
66
67 dmab->area = NULL;
68 dmab->addr = 0;
69 dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
70 if (! sgbuf)
71 return NULL;
72 if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) {
73 type = SNDRV_DMA_TYPE_DEV_UC;
74#ifdef pgprot_noncached
75 prot = pgprot_noncached(PAGE_KERNEL);
76#endif
77 }
78 sgbuf->dev = device;
79 pages = snd_sgbuf_aligned_pages(size);
80 sgbuf->tblsize = sgbuf_align_table(pages);
81 table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
82 if (!table)
83 goto _failed;
84 sgbuf->table = table;
85 pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
86 if (!pgtable)
87 goto _failed;
88 sgbuf->page_table = pgtable;
89
90 /* allocate pages */
91 maxpages = MAX_ALLOC_PAGES;
92 while (pages > 0) {
93 chunk = pages;
94 /* don't be too eager to take a huge chunk */
95 if (chunk > maxpages)
96 chunk = maxpages;
97 chunk <<= PAGE_SHIFT;
98 if (snd_dma_alloc_pages_fallback(type, device,
99 chunk, &tmpb) < 0) {
100 if (!sgbuf->pages)
101 goto _failed;
102 if (!res_size)
103 goto _failed;
104 size = sgbuf->pages * PAGE_SIZE;
105 break;
106 }
107 chunk = tmpb.bytes >> PAGE_SHIFT;
108 for (i = 0; i < chunk; i++) {
109 table->buf = tmpb.area;
110 table->addr = tmpb.addr;
111 if (!i)
112 table->addr |= chunk; /* mark head */
113 table++;
114 *pgtable++ = virt_to_page(tmpb.area);
115 tmpb.area += PAGE_SIZE;
116 tmpb.addr += PAGE_SIZE;
117 }
118 sgbuf->pages += chunk;
119 pages -= chunk;
120 if (chunk < maxpages)
121 maxpages = chunk;
122 }
123
124 sgbuf->size = size;
125 dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
126 if (! dmab->area)
127 goto _failed;
128 if (res_size)
129 *res_size = sgbuf->size;
130 return dmab->area;
131
132 _failed:
133 snd_free_sgbuf_pages(dmab); /* free the table */
134 return NULL;
135}
136
137/*
138 * compute the max chunk size with continuous pages on sg-buffer
139 */
140unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
141 unsigned int ofs, unsigned int size)
142{
143 struct snd_sg_buf *sg = dmab->private_data;
144 unsigned int start, end, pg;
145
146 start = ofs >> PAGE_SHIFT;
147 end = (ofs + size - 1) >> PAGE_SHIFT;
148 /* check page continuity */
149 pg = sg->table[start].addr >> PAGE_SHIFT;
150 for (;;) {
151 start++;
152 if (start > end)
153 break;
154 pg++;
155 if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
156 return (start << PAGE_SHIFT) - ofs;
157 }
158 /* ok, all on continuous pages */
159 return size;
160}
161EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);