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
|
/*
* videobuf2-memops.c - generic memory handling routines for videobuf2
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
* Marek Szyprowski <m.szyprowski@samsung.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/slab.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-memops.h>
/**
* vb2_create_framevec() - map virtual addresses to pfns
* @start: Virtual user address where we start mapping
* @length: Length of a range to map
* @write: Should we map for writing into the area
*
* This function allocates and fills in a vector with pfns corresponding to
* virtual address range passed in arguments. If pfns have corresponding pages,
* page references are also grabbed to pin pages in memory. The function
* returns pointer to the vector on success and error pointer in case of
* failure. Returned vector needs to be freed via vb2_destroy_pfnvec().
*/
struct frame_vector *vb2_create_framevec(unsigned long start,
unsigned long length,
bool write)
{
int ret;
unsigned long first, last;
unsigned long nr;
struct frame_vector *vec;
first = start >> PAGE_SHIFT;
last = (start + length - 1) >> PAGE_SHIFT;
nr = last - first + 1;
vec = frame_vector_create(nr);
if (!vec)
return ERR_PTR(-ENOMEM);
ret = get_vaddr_frames(start, nr, write, 1, vec);
if (ret < 0)
goto out_destroy;
/* We accept only complete set of PFNs */
if (ret != nr) {
ret = -EFAULT;
goto out_release;
}
return vec;
out_release:
put_vaddr_frames(vec);
out_destroy:
frame_vector_destroy(vec);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(vb2_create_framevec);
/**
* vb2_destroy_framevec() - release vector of mapped pfns
* @vec: vector of pfns / pages to release
*
* This releases references to all pages in the vector @vec (if corresponding
* pfns are backed by pages) and frees the passed vector.
*/
void vb2_destroy_framevec(struct frame_vector *vec)
{
put_vaddr_frames(vec);
frame_vector_destroy(vec);
}
EXPORT_SYMBOL(vb2_destroy_framevec);
/**
* vb2_common_vm_open() - increase refcount of the vma
* @vma: virtual memory region for the mapping
*
* This function adds another user to the provided vma. It expects
* struct vb2_vmarea_handler pointer in vma->vm_private_data.
*/
static void vb2_common_vm_open(struct vm_area_struct *vma)
{
struct vb2_vmarea_handler *h = vma->vm_private_data;
pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
__func__, h, atomic_read(h->refcount), vma->vm_start,
vma->vm_end);
atomic_inc(h->refcount);
}
/**
* vb2_common_vm_close() - decrease refcount of the vma
* @vma: virtual memory region for the mapping
*
* This function releases the user from the provided vma. It expects
* struct vb2_vmarea_handler pointer in vma->vm_private_data.
*/
static void vb2_common_vm_close(struct vm_area_struct *vma)
{
struct vb2_vmarea_handler *h = vma->vm_private_data;
pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
__func__, h, atomic_read(h->refcount), vma->vm_start,
vma->vm_end);
h->put(h->arg);
}
/**
* vb2_common_vm_ops - common vm_ops used for tracking refcount of mmaped
* video buffers
*/
const struct vm_operations_struct vb2_common_vm_ops = {
.open = vb2_common_vm_open,
.close = vb2_common_vm_close,
};
EXPORT_SYMBOL_GPL(vb2_common_vm_ops);
MODULE_DESCRIPTION("common memory handling routines for videobuf2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
MODULE_LICENSE("GPL");
|
