mirror of
https://github.com/apache/nuttx.git
synced 2026-05-28 03:45:50 +08:00
Add RAM disk support
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@765 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo
@@ -0,0 +1,250 @@
|
||||
/****************************************************************************
|
||||
* 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;
|
||||
}
|
||||
Reference in New Issue
Block a user