281 lines
9.0 KiB
C
281 lines
9.0 KiB
C
/****************************************************************************
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* drivers/ramdisk.c
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*
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* Copyright (C) 2008 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/fs.h>
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#include <nuttx/ramdisk.h>
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/****************************************************************************
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* Private Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct rd_struct_s
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{
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uint32 rd_nsectors; /* Number of sectors on device */
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uint16 rd_sectsize; /* The size of one sector */
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#ifdef CONFIG_FS_WRITABLE
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boolean rd_writeenabled; /* TRUE: can write to ram disk */
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ubyte *rd_buffer; /* RAM disk backup memory */
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#else
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const ubyte *rd_buffer; /* ROM disk backup memory */
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#endif
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int rd_open(FAR struct inode *inode);
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static int rd_close(FAR struct inode *inode);
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static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
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size_t start_sector, unsigned int nsectors);
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#ifdef CONFIG_FS_WRITABLE
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static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
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size_t start_sector, unsigned int nsectors);
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#endif
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static int rd_geometry(FAR struct inode *inode, struct geometry *geometry);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct block_operations g_bops =
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{
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rd_open, /* open */
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rd_close, /* close */
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rd_read, /* read */
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#ifdef CONFIG_FS_WRITABLE
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rd_write, /* write */
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#else
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NULL, /* write */
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#endif
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rd_geometry, /* geometry */
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NULL /* ioctl */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: rd_open
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*
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* Description: Open the block device
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*
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****************************************************************************/
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static int rd_open(FAR struct inode *inode)
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{
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return OK;
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}
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/****************************************************************************
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* Name: rd_closel
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*
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* Description: close the block device
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*
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****************************************************************************/
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static int rd_close(FAR struct inode *inode)
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{
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return OK;
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}
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/****************************************************************************
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* Name: rd_read
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*
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* Description: Read the specified numer of sectors
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*
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****************************************************************************/
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static ssize_t rd_read(FAR struct inode *inode, unsigned char *buffer,
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size_t start_sector, unsigned int nsectors)
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{
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struct rd_struct_s *dev;
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if (inode)
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{
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dev = (struct rd_struct_s *)inode->i_private;
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if (dev &&
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start_sector < dev->rd_nsectors &&
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start_sector + nsectors <= dev->rd_nsectors)
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{
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memcpy(buffer,
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&dev->rd_buffer[start_sector * dev->rd_sectsize],
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nsectors * dev->rd_sectsize);
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return nsectors;
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}
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}
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return -EINVAL;
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}
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/****************************************************************************
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* Name: rd_write
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*
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* Description: Write the specified number of sectors
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*
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****************************************************************************/
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#ifdef CONFIG_FS_WRITABLE
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static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
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size_t start_sector, unsigned int nsectors)
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{
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struct rd_struct_s *dev;
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if (inode)
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{
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dev = (struct rd_struct_s *)inode->i_private;
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if (dev)
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{
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if (!dev->rd_writeenabled)
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{
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return -EACCES;
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}
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else if (start_sector < dev->rd_nsectors &&
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start_sector + nsectors <= dev->rd_nsectors)
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{
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memcpy(&dev->rd_buffer[start_sector * dev->rd_sectsize],
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buffer,
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nsectors * dev->rd_sectsize);
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return nsectors;
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}
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}
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}
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return -EINVAL;
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}
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#endif
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/****************************************************************************
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* Name: rd_geometry
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*
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* Description: Return device geometry
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*
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****************************************************************************/
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static int rd_geometry(FAR struct inode *inode, struct geometry *geometry)
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{
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struct rd_struct_s *dev;
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if (inode && geometry)
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{
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dev = (struct rd_struct_s *)inode->i_private;
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geometry->geo_available = TRUE;
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geometry->geo_mediachanged = FALSE;
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#ifdef CONFIG_FS_WRITABLE
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geometry->geo_writeenabled = dev->rd_writeenabled;
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#else
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geometry->geo_writeenabled = FALSE;
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#endif
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geometry->geo_nsectors = dev->rd_nsectors;
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geometry->geo_sectorsize = dev->rd_sectsize;
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return OK;
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}
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return -EINVAL;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ramdisk_register
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*
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* Description: Register the a ramdisk
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****************************************************************************/
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#ifdef CONFIG_FS_WRITABLE
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int ramdisk_register(int minor, ubyte *buffer, uint32 nsectors, uint16 sectsize,
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boolean writeenabled)
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#else
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int romdisk_register(int minor, ubyte *buffer, uint32 nsectors, uint16 sectsize)
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#endif
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{
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struct rd_struct_s *dev;
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char devname[16];
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int ret = -ENOMEM;
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/* Sanity check */
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#ifdef CONFIG_DEBUG
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if (minor < 0 || minor > 255 || !buffer || !nsectors || !sectsize)
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{
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return -EINVAL;
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}
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#endif
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/* Allocate a ramdisk device structure */
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dev = (struct rd_struct_s *)malloc(sizeof(struct rd_struct_s));
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if (dev)
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{
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/* Initialize the ramdisk device structure */
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dev->rd_nsectors = nsectors; /* Number of sectors on device */
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dev->rd_sectsize = sectsize; /* The size of one sector */
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#ifdef CONFIG_FS_WRITABLE
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dev->rd_writeenabled = writeenabled; /* TRUE: can write to ram disk */
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#endif
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dev->rd_buffer = buffer; /* RAM disk backup memory */
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/* Create a ramdisk device name */
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snprintf(devname, 16, "/dev/ram%d", minor);
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/* Inode private data is a reference to the ramdisk device stgructure */
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ret = register_blockdriver(devname, &g_bops, 0, dev);
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if (ret < 0)
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{
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fdbg("register_blockdriver failed: %d\n", -ret);
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free(dev);
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}
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}
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return ret;
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}
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