/**************************************************************************** * drivers/ramdisk.c * * Copyright (C) 2008 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include /**************************************************************************** * 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; }