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
|
/****************************************************************************
* fs/mmap/rammap.h
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References: Linux/Documentation/filesystems/romfs.txt
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __FS_MMAP_RAMMAP_H
#define __FS_MMAP_RAMMAP_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <semaphore.h>
#ifdef CONFIG_FS_RAMMAP
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Types
****************************************************************************/
/* This structure describes one file that has been copied to memory and
* managed as a share-able "memory mapped" file. This functionality is
* intended to provide a substitute for memory mapped files for architectures
* that do not have MMUs and, hence, cannot support on demand paging of
* blocks of a file.
*
* This copied file has many of the properties of a standard memory mapped
* file except:
*
* - All of the file must be present in memory. This limits the size of
* files that may be memory mapped (especially on MCUs with no significant
* RAM resources).
* - All mapped files are read-only. You can write to the in-memory image,
* but the file contents will not change.
* - There are not access privileges.
*/
struct fs_rammap_s
{
struct fs_rammap_s *flink; /* Implements a singly linked list */
FAR void *addr; /* Start of allocated memory */
size_t length; /* Length of region */
off_t offset; /* File offset */
};
/* This structure defines all "mapped" files */
struct fs_allmaps_s
{
bool initialized; /* True: This structure has been initialized */
sem_t exclsem; /* Provides exclusive access the list */
struct fs_rammap_s *head; /* List of mapped files */
};
/****************************************************************************
* Public Variables
****************************************************************************/
/* This is the list of all mapped files */
extern struct fs_allmaps_s g_rammaps;
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: rammap_initialize
*
* Description:
* Verified that this capability has been initialized.
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
extern void rammap_initialize(void);
/****************************************************************************
* Name: rammmap
*
* Description:
* Support simulation of memory mapped files by copying files into RAM.
*
* Parameters:
* fd file descriptor of the backing file -- required.
* length The length of the mapping. For exception #1 above, this length
* ignored: The entire underlying media is always accessible.
* offset The offset into the file to map
*
* Returned Value:
* On success, rammmap() returns a pointer to the mapped area. On error, the
* value MAP_FAILED is returned, and errno is set appropriately.
*
* EBADF
* 'fd' is not a valid file descriptor.
* EINVAL
* 'length' or 'offset' are invalid
* ENOMEM
* Insufficient memory is available to map the file.
*
****************************************************************************/
extern FAR void *rammap(int fd, size_t length, off_t offset);
#endif /* CONFIG_FS_RAMMAP */
#endif /* __FS_MMAP_RAMMAP_H */
|
