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diff --git a/nuttx/fs/mmap/fs_rammap.h b/nuttx/fs/mmap/fs_rammap.h
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+/****************************************************************************
+ * fs/mmap/rammap.h
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 */