459 lines
13 KiB
C
459 lines
13 KiB
C
/****************************************************************************
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* drivers/misc/ramdisk.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <sys/ioctl.h>
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#include <inttypes.h>
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#include <stdint.h>
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#include <stdbool.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 <assert.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/drivers/ramdisk.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Helpers for rdflags */
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/* User input flags */
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#define RDFLAG_USER (RDFLAG_WRENABLED | RDFLAG_FUNLINK)
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#define RDFLAG_IS_WRENABLED(f) (((f) & RDFLAG_WRENABLED) != 0)
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#define RDFLAG_IS_FUNLINK(f) (((f) & RDFLAG_WRENABLED) != 0)
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/* Flag set when the RAM disk block driver is unlink */
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#define RDFLAG_UNLINK(f) do { (f) |= RDFLAG_UNLINKED; } while (0)
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#define RDFLAG_IS_UNLINKED(f) (((f) & RDFLAG_UNLINKED) != 0)
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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_t rd_nsectors; /* Number of sectors on device */
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uint16_t rd_sectsize; /* The size of one sector */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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uint8_t rd_crefs; /* Open reference count */
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#endif
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uint8_t rd_flags; /* See RDFLAG_* definitions */
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FAR uint8_t *rd_buffer; /* RAM disk backup memory */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static void rd_destroy(FAR struct rd_struct_s *dev);
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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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#endif
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static ssize_t rd_read(FAR struct inode *inode, FAR unsigned char *buffer,
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blkcnt_t start_sector, unsigned int nsectors);
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static ssize_t rd_write(FAR struct inode *inode,
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FAR const unsigned char *buffer, blkcnt_t start_sector,
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unsigned int nsectors);
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static int rd_geometry(FAR struct inode *inode,
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FAR struct geometry *geometry);
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static int rd_ioctl(FAR struct inode *inode, int cmd,
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unsigned long arg);
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int rd_unlink(FAR struct inode *inode);
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#endif
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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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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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rd_open, /* open */
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rd_close, /* close */
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#else
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0, /* open */
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0, /* close */
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#endif
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rd_read, /* read */
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rd_write, /* write */
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rd_geometry, /* geometry */
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rd_ioctl, /* ioctl */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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rd_unlink /* unlink */
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#endif
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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_destroy
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*
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* Description:
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* Free all resources used by the RAM disk
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*
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static void rd_destroy(FAR struct rd_struct_s *dev)
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{
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finfo("Destroying RAM disk\n");
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/* We we configured to free the RAM disk memory when unlinked? */
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if (RDFLAG_IS_UNLINKED(dev->rd_flags))
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{
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/* Yes.. do it */
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kmm_free(dev->rd_buffer);
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}
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/* And free the block driver itself */
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kmm_free(dev);
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}
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#endif
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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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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int rd_open(FAR struct inode *inode)
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{
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FAR struct rd_struct_s *dev;
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DEBUGASSERT(inode && inode->i_private);
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dev = (FAR struct rd_struct_s *)inode->i_private;
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/* Increment the open reference count */
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dev->rd_crefs++;
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DEBUGASSERT(dev->rd_crefs > 0);
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finfo("rd_crefs: %d\n", dev->rd_crefs);
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return OK;
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}
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#endif
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/****************************************************************************
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* Name: rd_close
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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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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int rd_close(FAR struct inode *inode)
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{
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FAR struct rd_struct_s *dev;
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DEBUGASSERT(inode && inode->i_private);
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dev = (FAR struct rd_struct_s *)inode->i_private;
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/* Increment the open reference count */
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DEBUGASSERT(dev->rd_crefs > 0);
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dev->rd_crefs--;
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finfo("rd_crefs: %d\n", dev->rd_crefs);
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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/* Was that the last open reference to the RAM disk? */
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if (dev->rd_crefs == 0)
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{
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/* Yes.. Have we been unlinked? */
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if (RDFLAG_IS_UNLINKED(dev->rd_flags))
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{
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/* Yes.. Release all of the RAM disk resources */
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rd_destroy(dev);
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}
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}
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#endif
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return OK;
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}
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#endif
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/****************************************************************************
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* Name: rd_read
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*
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* Description: Read the specified number 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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blkcnt_t start_sector, unsigned int nsectors)
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{
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FAR struct rd_struct_s *dev;
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DEBUGASSERT(inode && inode->i_private);
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dev = (FAR struct rd_struct_s *)inode->i_private;
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finfo("sector: %" PRIuOFF " nsectors: %u sectorsize: %d\n",
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start_sector, nsectors, dev->rd_sectsize);
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if (start_sector < dev->rd_nsectors &&
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start_sector + nsectors <= dev->rd_nsectors)
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{
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finfo("Transfer %d bytes from %p\n",
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nsectors * dev->rd_sectsize,
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&dev->rd_buffer[start_sector * dev->rd_sectsize]);
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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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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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static ssize_t rd_write(FAR struct inode *inode, const unsigned char *buffer,
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blkcnt_t start_sector, unsigned int nsectors)
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{
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struct rd_struct_s *dev;
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DEBUGASSERT(inode && inode->i_private);
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dev = (struct rd_struct_s *)inode->i_private;
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finfo("sector: %" PRIuOFF " nsectors: %u sectorsize: %d\n",
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start_sector, nsectors, dev->rd_sectsize);
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if (!RDFLAG_IS_WRENABLED(dev->rd_flags))
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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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finfo("Transfer %d bytes to %p\n",
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nsectors * dev->rd_sectsize,
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&dev->rd_buffer[start_sector * dev->rd_sectsize]);
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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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return -EFBIG;
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}
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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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finfo("Entry\n");
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DEBUGASSERT(inode);
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if (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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geometry->geo_writeenabled = RDFLAG_IS_WRENABLED(dev->rd_flags);
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geometry->geo_nsectors = dev->rd_nsectors;
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geometry->geo_sectorsize = dev->rd_sectsize;
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finfo("available: true mediachanged: false writeenabled: %s\n",
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geometry->geo_writeenabled ? "true" : "false");
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finfo("nsectors: %" PRIuOFF " sectorsize: %" PRIi16 "\n",
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geometry->geo_nsectors, geometry->geo_sectorsize);
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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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* Name: rd_ioctl
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*
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* Description:
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* Return device geometry
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*
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****************************************************************************/
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static int rd_ioctl(FAR struct inode *inode, int cmd, unsigned long arg)
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{
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FAR struct rd_struct_s *dev;
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FAR void **ppv = (void**)((uintptr_t)arg);
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finfo("Entry\n");
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/* Only one ioctl command is supported */
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DEBUGASSERT(inode && inode->i_private);
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if (cmd == BIOC_XIPBASE && ppv)
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{
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dev = (FAR struct rd_struct_s *)inode->i_private;
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*ppv = (FAR void *)dev->rd_buffer;
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finfo("ppv: %p\n", *ppv);
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return OK;
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}
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return -ENOTTY;
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}
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/****************************************************************************
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* Name: rd_unlink
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*
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* Description:
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* The block driver has been unlinked.
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*
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int rd_unlink(FAR struct inode *inode)
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{
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FAR struct rd_struct_s *dev;
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DEBUGASSERT(inode && inode->i_private);
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dev = (FAR struct rd_struct_s *)inode->i_private;
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/* Mark the pipe unlinked */
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RDFLAG_UNLINK(dev->rd_flags);
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/* Are the any open references to the driver? */
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if (dev->rd_crefs == 0)
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{
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/* No... release all resources held by the block driver */
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rd_destroy(dev);
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}
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return OK;
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}
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#endif
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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 or romdisk_register
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*
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* Description:
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* Non-standard function to register a ramdisk or a romdisk
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*
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* Input Parameters:
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* minor: Selects suffix of device named /dev/ramN, N={1,2,3...}
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* nsectors: Number of sectors on device
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* sectize: The size of one sector
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* rdflags: See RDFLAG_* definitions
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* buffer: RAM disk backup memory
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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int ramdisk_register(int minor, FAR uint8_t *buffer, uint32_t nsectors,
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uint16_t sectsize, uint8_t rdflags)
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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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finfo("buffer: %p nsectors: %" PRIu32 " sectsize: %" PRIu16 "\n",
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buffer, nsectors, sectsize);
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/* Sanity check */
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#ifdef CONFIG_DEBUG_FEATURES
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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 *)kmm_zalloc(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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dev->rd_buffer = buffer; /* RAM disk backup memory */
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dev->rd_flags = rdflags & RDFLAG_USER;
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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 structure */
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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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ferr("register_blockdriver failed: %d\n", -ret);
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kmm_free(dev);
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}
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}
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return ret;
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}
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