px4-firmware/nuttx/drivers/ramdisk.c

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/****************************************************************************
* drivers/ramdisk.c
*
* Copyright (C) 2008-2009, 2011 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 <sys/ioctl.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <debug.h>
#include <errno.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/ramdisk.h>
/****************************************************************************
* Private Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
struct rd_struct_s
{
uint32_t rd_nsectors; /* Number of sectors on device */
uint16_t rd_sectsize; /* The size of one sector */
#ifdef CONFIG_FS_WRITABLE
bool rd_writeenabled; /* true: can write to ram disk */
uint8_t *rd_buffer; /* RAM disk backup memory */
#else
const uint8_t *rd_buffer; /* ROM disk backup memory */
#endif
};
/****************************************************************************
* 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);
#ifdef CONFIG_FS_WRITABLE
static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
size_t start_sector, unsigned int nsectors);
#endif
static int rd_geometry(FAR struct inode *inode, struct geometry *geometry);
static int rd_ioctl(FAR struct inode *inode, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct block_operations g_bops =
{
rd_open, /* open */
rd_close, /* close */
rd_read, /* read */
#ifdef CONFIG_FS_WRITABLE
rd_write, /* write */
#else
NULL, /* write */
#endif
rd_geometry, /* geometry */
rd_ioctl /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: rd_open
*
* Description: Open the block device
*
****************************************************************************/
static int rd_open(FAR struct inode *inode)
{
fvdbg("Entry\n");
return OK;
}
/****************************************************************************
* Name: rd_closel
*
* Description: close the block device
*
****************************************************************************/
static int rd_close(FAR struct inode *inode)
{
fvdbg("Entry\n");
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;
DEBUGASSERT(inode && inode->i_private);
dev = (struct rd_struct_s *)inode->i_private;
fvdbg("sector: %d nsectors: %d sectorsize: %d\n",
start_sector, dev->rd_sectsize, nsectors);
if (start_sector < dev->rd_nsectors &&
start_sector + nsectors <= dev->rd_nsectors)
{
fvdbg("Transfer %d bytes from %p\n",
nsectors * dev->rd_sectsize,
&dev->rd_buffer[start_sector * dev->rd_sectsize]);
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
*
****************************************************************************/
#ifdef CONFIG_FS_WRITABLE
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;
DEBUGASSERT(inode && inode->i_private);
dev = (struct rd_struct_s *)inode->i_private;
fvdbg("sector: %d nsectors: %d sectorsize: %d\n",
start_sector, dev->rd_sectsize, nsectors);
if (!dev->rd_writeenabled)
{
return -EACCES;
}
else if (start_sector < dev->rd_nsectors &&
start_sector + nsectors <= dev->rd_nsectors)
{
fvdbg("Transfer %d bytes from %p\n",
nsectors * dev->rd_sectsize,
&dev->rd_buffer[start_sector * dev->rd_sectsize]);
memcpy(&dev->rd_buffer[start_sector * dev->rd_sectsize],
buffer,
nsectors * dev->rd_sectsize);
return nsectors;
}
return -EFBIG;
}
#endif
/****************************************************************************
* Name: rd_geometry
*
* Description: Return device geometry
*
****************************************************************************/
static int rd_geometry(FAR struct inode *inode, struct geometry *geometry)
{
struct rd_struct_s *dev;
fvdbg("Entry\n");
DEBUGASSERT(inode);
if (geometry)
{
dev = (struct rd_struct_s *)inode->i_private;
geometry->geo_available = true;
geometry->geo_mediachanged = false;
#ifdef CONFIG_FS_WRITABLE
geometry->geo_writeenabled = dev->rd_writeenabled;
#else
geometry->geo_writeenabled = false;
#endif
geometry->geo_nsectors = dev->rd_nsectors;
geometry->geo_sectorsize = dev->rd_sectsize;
fvdbg("available: true mediachanged: false writeenabled: %s\n",
geometry->geo_writeenabled ? "true" : "false");
fvdbg("nsectors: %d sectorsize: %d\n",
geometry->geo_nsectors, geometry->geo_sectorsize);
return OK;
}
return -EINVAL;
}
/****************************************************************************
* Name: rd_ioctl
*
* Description: Return device geometry
*
****************************************************************************/
static int rd_ioctl(FAR struct inode *inode, int cmd, unsigned long arg)
{
struct rd_struct_s *dev ;
void **ppv = (void**)((uintptr_t)arg);
fvdbg("Entry\n");
/* Only one ioctl command is supported */
DEBUGASSERT(inode && inode->i_private);
if (cmd == BIOC_XIPBASE && ppv)
{
dev = (struct rd_struct_s *)inode->i_private;
*ppv = (void*)dev->rd_buffer;
fvdbg("ppv: %p\n", *ppv);
return OK;
}
return -ENOTTY;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ramdisk_register
*
* Description: Register the a ramdisk
****************************************************************************/
#ifdef CONFIG_FS_WRITABLE
int ramdisk_register(int minor, uint8_t *buffer, uint32_t nsectors,
uint16_t sectsize, bool writeenabled)
#else
int romdisk_register(int minor, uint8_t *buffer, uint32_t nsectors,
uint16_t sectsize)
#endif
{
struct rd_struct_s *dev;
char devname[16];
int ret = -ENOMEM;
fvdbg("buffer: %p nsectors: %d sectsize: %d\n", buffer, nsectors, sectsize);
/* 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 *)kmalloc(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 */
#ifdef CONFIG_FS_WRITABLE
dev->rd_writeenabled = writeenabled; /* true: can write to ram disk */
#endif
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)
{
fdbg("register_blockdriver failed: %d\n", -ret);
kfree(dev);
}
}
return ret;
}