summaryrefslogtreecommitdiff
path: root/sound/core/sgbuf.c
blob: 29ddb76187e57d4a85b5a6e980edaf3b515f882a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Scatter-Gather buffer
 *
 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
 */

#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <sound/memalloc.h>


/* table entries are align to 32 */
#define SGBUF_TBL_ALIGN		32
#define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)

int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
{
	struct snd_sg_buf *sgbuf = dmab->private_data;
	struct snd_dma_buffer tmpb;
	int i;

	if (! sgbuf)
		return -EINVAL;

	vunmap(dmab->area);
	dmab->area = NULL;

	tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG)
		tmpb.dev.type = SNDRV_DMA_TYPE_DEV_UC;
	tmpb.dev.dev = sgbuf->dev;
	for (i = 0; i < sgbuf->pages; i++) {
		if (!(sgbuf->table[i].addr & ~PAGE_MASK))
			continue; /* continuous pages */
		tmpb.area = sgbuf->table[i].buf;
		tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
		tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
		snd_dma_free_pages(&tmpb);
	}

	kfree(sgbuf->table);
	kfree(sgbuf->page_table);
	kfree(sgbuf);
	dmab->private_data = NULL;
	
	return 0;
}

#define MAX_ALLOC_PAGES		32

void *snd_malloc_sgbuf_pages(struct device *device,
			     size_t size, struct snd_dma_buffer *dmab,
			     size_t *res_size)
{
	struct snd_sg_buf *sgbuf;
	unsigned int i, pages, chunk, maxpages;
	struct snd_dma_buffer tmpb;
	struct snd_sg_page *table;
	struct page **pgtable;
	int type = SNDRV_DMA_TYPE_DEV;
	pgprot_t prot = PAGE_KERNEL;

	dmab->area = NULL;
	dmab->addr = 0;
	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
	if (! sgbuf)
		return NULL;
	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) {
		type = SNDRV_DMA_TYPE_DEV_UC;
#ifdef pgprot_noncached
		prot = pgprot_noncached(PAGE_KERNEL);
#endif
	}
	sgbuf->dev = device;
	pages = snd_sgbuf_aligned_pages(size);
	sgbuf->tblsize = sgbuf_align_table(pages);
	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
	if (!table)
		goto _failed;
	sgbuf->table = table;
	pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
	if (!pgtable)
		goto _failed;
	sgbuf->page_table = pgtable;

	/* allocate pages */
	maxpages = MAX_ALLOC_PAGES;
	while (pages > 0) {
		chunk = pages;
		/* don't be too eager to take a huge chunk */
		if (chunk > maxpages)
			chunk = maxpages;
		chunk <<= PAGE_SHIFT;
		if (snd_dma_alloc_pages_fallback(type, device,
						 chunk, &tmpb) < 0) {
			if (!sgbuf->pages)
				goto _failed;
			if (!res_size)
				goto _failed;
			size = sgbuf->pages * PAGE_SIZE;
			break;
		}
		chunk = tmpb.bytes >> PAGE_SHIFT;
		for (i = 0; i < chunk; i++) {
			table->buf = tmpb.area;
			table->addr = tmpb.addr;
			if (!i)
				table->addr |= chunk; /* mark head */
			table++;
			*pgtable++ = virt_to_page(tmpb.area);
			tmpb.area += PAGE_SIZE;
			tmpb.addr += PAGE_SIZE;
		}
		sgbuf->pages += chunk;
		pages -= chunk;
		if (chunk < maxpages)
			maxpages = chunk;
	}

	sgbuf->size = size;
	dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
	if (! dmab->area)
		goto _failed;
	if (res_size)
		*res_size = sgbuf->size;
	return dmab->area;

 _failed:
	snd_free_sgbuf_pages(dmab); /* free the table */
	return NULL;
}

/*
 * compute the max chunk size with continuous pages on sg-buffer
 */
unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
				      unsigned int ofs, unsigned int size)
{
	struct snd_sg_buf *sg = dmab->private_data;
	unsigned int start, end, pg;

	if (!sg)
		return size;

	start = ofs >> PAGE_SHIFT;
	end = (ofs + size - 1) >> PAGE_SHIFT;
	/* check page continuity */
	pg = sg->table[start].addr >> PAGE_SHIFT;
	for (;;) {
		start++;
		if (start > end)
			break;
		pg++;
		if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
			return (start << PAGE_SHIFT) - ofs;
	}
	/* ok, all on continuous pages */
	return size;
}
EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);