147 lines
5.4 KiB
C
147 lines
5.4 KiB
C
/****************************************************************************
|
|
* 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 <nuttx/semaphore.h>
|
|
|
|
#ifdef CONFIG_FS_RAMMAP
|
|
|
|
/****************************************************************************
|
|
* 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 Data
|
|
****************************************************************************/
|
|
|
|
/* 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
|
|
*
|
|
****************************************************************************/
|
|
|
|
void rammap_initialize(void);
|
|
|
|
/****************************************************************************
|
|
* Name: rammmap
|
|
*
|
|
* Description:
|
|
* Support simulation of memory mapped files by copying files into RAM.
|
|
*
|
|
* Input 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
FAR void *rammap(int fd, size_t length, off_t offset);
|
|
|
|
#endif /* CONFIG_FS_RAMMAP */
|
|
#endif /* __FS_MMAP_RAMMAP_H */
|