aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/media/video/videobuf2-dma-contig.c
blob: a790a5f8c06ff5e48566bfeb41a512975fc26d4f (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
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
/*
 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Pawel Osciak <pawel@osciak.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>

#include <media/videobuf2-core.h>
#include <media/videobuf2-memops.h>

struct vb2_dc_conf {
	struct device		*dev;
};

struct vb2_dc_buf {
	struct vb2_dc_conf		*conf;
	void				*vaddr;
	dma_addr_t			paddr;
	unsigned long			size;
	struct vm_area_struct		*vma;
	atomic_t			refcount;
	struct vb2_vmarea_handler	handler;
};

static void vb2_dma_contig_put(void *buf_priv);

static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
{
	struct vb2_dc_conf *conf = alloc_ctx;
	struct vb2_dc_buf *buf;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->paddr,
					GFP_KERNEL);
	if (!buf->vaddr) {
		dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
			size);
		kfree(buf);
		return ERR_PTR(-ENOMEM);
	}

	buf->conf = conf;
	buf->size = size;

	buf->handler.refcount = &buf->refcount;
	buf->handler.put = vb2_dma_contig_put;
	buf->handler.arg = buf;

	atomic_inc(&buf->refcount);

	return buf;
}

static void vb2_dma_contig_put(void *buf_priv)
{
	struct vb2_dc_buf *buf = buf_priv;

	if (atomic_dec_and_test(&buf->refcount)) {
		dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
				  buf->paddr);
		kfree(buf);
	}
}

static void *vb2_dma_contig_cookie(void *buf_priv)
{
	struct vb2_dc_buf *buf = buf_priv;

	return &buf->paddr;
}

static void *vb2_dma_contig_vaddr(void *buf_priv)
{
	struct vb2_dc_buf *buf = buf_priv;
	if (!buf)
		return 0;

	return buf->vaddr;
}

static unsigned int vb2_dma_contig_num_users(void *buf_priv)
{
	struct vb2_dc_buf *buf = buf_priv;

	return atomic_read(&buf->refcount);
}

static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
{
	struct vb2_dc_buf *buf = buf_priv;

	if (!buf) {
		printk(KERN_ERR "No buffer to map\n");
		return -EINVAL;
	}

	return vb2_mmap_pfn_range(vma, buf->paddr, buf->size,
				  &vb2_common_vm_ops, &buf->handler);
}

static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
					unsigned long size, int write)
{
	struct vb2_dc_buf *buf;
	struct vm_area_struct *vma;
	dma_addr_t paddr = 0;
	int ret;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	ret = vb2_get_contig_userptr(vaddr, size, &vma, &paddr);
	if (ret) {
		printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
				vaddr);
		kfree(buf);
		return ERR_PTR(ret);
	}

	buf->size = size;
	buf->paddr = paddr;
	buf->vma = vma;

	return buf;
}

static void vb2_dma_contig_put_userptr(void *mem_priv)
{
	struct vb2_dc_buf *buf = mem_priv;

	if (!buf)
		return;

	vb2_put_vma(buf->vma);
	kfree(buf);
}

const struct vb2_mem_ops vb2_dma_contig_memops = {
	.alloc		= vb2_dma_contig_alloc,
	.put		= vb2_dma_contig_put,
	.cookie		= vb2_dma_contig_cookie,
	.vaddr		= vb2_dma_contig_vaddr,
	.mmap		= vb2_dma_contig_mmap,
	.get_userptr	= vb2_dma_contig_get_userptr,
	.put_userptr	= vb2_dma_contig_put_userptr,
	.num_users	= vb2_dma_contig_num_users,
};
EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);

void *vb2_dma_contig_init_ctx(struct device *dev)
{
	struct vb2_dc_conf *conf;

	conf = kzalloc(sizeof *conf, GFP_KERNEL);
	if (!conf)
		return ERR_PTR(-ENOMEM);

	conf->dev = dev;

	return conf;
}
EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);

void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
{
	kfree(alloc_ctx);
}
EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);

MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
MODULE_LICENSE("GPL");