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/****************************************************************************
* drivers/ramdisk.c
*
* Copyright (C) 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <nuttx/fs.h>
#include <nuttx/ramdisk.h>
/****************************************************************************
* Private Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
struct rd_struct_s
{
uint32 rd_nsectors; /* Number of sectors on device */
uint16 rd_sectsize; /* The size of one sector */
boolean rd_writeenabled; /* TRUE: can write to ram disk */
ubyte *rd_buffer; /* RAM disk backup memory */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int rd_open(FAR struct inode *inode);
static int rd_close(FAR struct inode *inode);
static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
size_t start_sector, unsigned int nsectors);
static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
size_t start_sector, unsigned int nsectors);
static int rd_geometry(FAR struct inode *inode, struct geometry *geometry);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct block_operations g_bops =
{
rd_open, /* open */
rd_close, /* close */
rd_read, /* read */
rd_write, /* write */
rd_geometry, /* geometry */
NULL /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: rd_open
*
* Description: Open the block device
*
****************************************************************************/
static int rd_open(FAR struct inode *inode)
{
return OK;
}
/****************************************************************************
* Name: rd_closel
*
* Description: close the block device
*
****************************************************************************/
static int rd_close(FAR struct inode *inode)
{
return OK;
}
/****************************************************************************
* Name: rd_read
*
* Description: Read the specified numer of sectors
*
****************************************************************************/
static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
size_t start_sector, unsigned int nsectors)
{
struct rd_struct_s *dev;
if (inode)
{
dev = (struct rd_struct_s *)inode->i_private;
if (dev &&
start_sector < dev->rd_nsectors &&
start_sector + nsectors <= dev->rd_nsectors)
{
memcpy(buffer,
&dev->rd_buffer[start_sector * dev->rd_sectsize],
nsectors * dev->rd_sectsize);
return nsectors;
}
}
return -EINVAL;
}
/****************************************************************************
* Name: rd_write
*
* Description: Write the specified number of sectors
*
****************************************************************************/
static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
size_t start_sector, unsigned int nsectors)
{
struct rd_struct_s *dev;
if (inode)
{
dev = (struct rd_struct_s *)inode->i_private;
if (dev &&
start_sector < dev->rd_nsectors &&
start_sector + nsectors <= dev->rd_nsectors)
{
memcpy(&dev->rd_buffer[start_sector * dev->rd_sectsize],
buffer,
nsectors * dev->rd_sectsize);
return nsectors;
}
}
return -EINVAL;
}
/****************************************************************************
* Name: rd_geometry
*
* Description: Return device geometry
*
****************************************************************************/
static int rd_geometry(FAR struct inode *inode, struct geometry *geometry)
{
struct rd_struct_s *dev;
if (inode && geometry)
{
dev = (struct rd_struct_s *)inode->i_private;
geometry->geo_available = TRUE;
geometry->geo_mediachanged = FALSE;
geometry->geo_writeenabled = dev->rd_writeenabled;
geometry->geo_nsectors = dev->rd_nsectors;
geometry->geo_sectorsize = dev->rd_sectsize;
return OK;
}
return -EINVAL;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: rd_register
*
* Description: Register the a ramdisk
****************************************************************************/
int rd_register(int minor, ubyte *buffer, uint32 nsectors, uint16 sectsize,
boolean writeenabled)
{
struct rd_struct_s *dev;
char devname[16];
int ret = -ENOMEM;
/* Sanity check */
#ifdef CONFIG_DEBUG
if (minor < 0 || minor > 255 || !buffer || !nsectors || !sectsize)
{
return -EINVAL;
}
#endif
/* Allocate a ramdisk device structure */
dev = (struct rd_struct_s *)malloc(sizeof(struct rd_struct_s));
if (dev)
{
/* Initialize the ramdisk device structure */
dev->rd_nsectors = nsectors; /* Number of sectors on device */
dev->rd_sectsize = sectsize; /* The size of one sector */
dev->rd_writeenabled = writeenabled; /* TRUE: can write to ram disk */
dev->rd_buffer = buffer; /* RAM disk backup memory */
/* Create a ramdisk device name */
snprintf(devname, 16, "/dev/ram%d", minor);
/* Inode private data is a reference to the ramdisk device stgructure */
ret = register_blockdriver(devname, &g_bops, 0, dev);
if (ret < 0)
{
free(dev);
}
}
return ret;
}
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