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incubator-nuttx/drivers/bch/bchdev_driver.c

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/****************************************************************************
* drivers/bch/bchdev_driver.c
*
* Copyright (C) 2008-2009, 2014-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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/stat.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sched.h>
#include <errno.h>
#include <poll.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/drivers/drivers.h>
#include "bch.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int bch_open(FAR struct file *filep);
static int bch_close(FAR struct file *filep);
static off_t bch_seek(FAR struct file *filep, off_t offset, int whence);
static ssize_t bch_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t bch_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int bch_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
static int bch_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int bch_unlink(FAR struct inode *inode);
#endif
/****************************************************************************
* Public Data
****************************************************************************/
const struct file_operations bch_fops =
{
bch_open, /* open */
bch_close, /* close */
bch_read, /* read */
bch_write, /* write */
bch_seek, /* seek */
bch_ioctl, /* ioctl */
bch_poll /* poll */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, bch_unlink /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: bch_poll
****************************************************************************/
static int bch_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
if (setup)
{
fds->revents |= (fds->events & (POLLIN | POLLOUT));
if (fds->revents != 0)
{
nxsem_post(fds->sem);
}
}
return OK;
}
/****************************************************************************
* Name: bch_open
*
* Description: Open the block device
*
****************************************************************************/
static int bch_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
int ret = OK;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
/* Increment the reference count */
bchlib_semtake(bch);
if (bch->refs == MAX_OPENCNT)
{
ret = -EMFILE;
}
else
{
bch->refs++;
}
bchlib_semgive(bch);
return ret;
}
/****************************************************************************
* Name: bch_close
*
* Description: close the block device
*
****************************************************************************/
static int bch_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
int ret = OK;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
/* Flush any dirty pages remaining in the cache */
bchlib_semtake(bch);
bchlib_flushsector(bch);
/* Decrement the reference count (I don't use bchlib_decref() because I
* want the entire close operation to be atomic wrt other driver
* operations.
*/
if (bch->refs == 0)
{
ret = -EIO;
}
else
{
bch->refs--;
/* If the reference count decremented to zero AND if the character
* driver has been unlinked, then teardown the BCH device now.
*/
if (bch->refs == 0 && bch->unlinked)
{
/* Tear the driver down now. */
ret = bchlib_teardown((FAR void *)bch);
/* bchlib_teardown() would only fail if there are outstanding
* references on the device. Since we know that is not true, it
* should not fail at all.
*/
DEBUGASSERT(ret >= 0);
if (ret >= 0)
{
/* Return without releasing the stale semaphore */
return OK;
}
}
}
bchlib_semgive(bch);
return ret;
}
/****************************************************************************
* Name: bch_seek
****************************************************************************/
static off_t bch_seek(FAR struct file *filep, off_t offset, int whence)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
off_t newpos;
int ret;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
bchlib_semtake(bch);
/* Determine the new, requested file position */
switch (whence)
{
case SEEK_CUR:
newpos = filep->f_pos + offset;
break;
case SEEK_SET:
newpos = offset;
break;
case SEEK_END:
newpos = bch->sectsize * bch->nsectors + offset;
break;
default:
/* Return EINVAL if the whence argument is invalid */
bchlib_semgive(bch);
return -EINVAL;
}
/* Opengroup.org:
*
* "The lseek() function shall allow the file offset to be set beyond the end
* of the existing data in the file. If data is later written at this point,
* subsequent reads of data in the gap shall return bytes with the value 0
* until data is actually written into the gap."
*
* We can conform to the first part, but not the second. But return EINVAL if
*
* "...the resulting file offset would be negative for a regular file, block
* special file, or directory."
*/
if (newpos >= 0)
{
filep->f_pos = newpos;
ret = newpos;
}
else
{
ret = -EINVAL;
}
bchlib_semgive(bch);
return ret;
}
/****************************************************************************
* Name: bch_read
****************************************************************************/
static ssize_t bch_read(FAR struct file *filep, FAR char *buffer, size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
int ret;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
bchlib_semtake(bch);
ret = bchlib_read(bch, buffer, filep->f_pos, len);
if (ret > 0)
{
filep->f_pos += len;
}
bchlib_semgive(bch);
return ret;
}
/****************************************************************************
* Name: bch_write
****************************************************************************/
static ssize_t bch_write(FAR struct file *filep, FAR const char *buffer, size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
int ret = -EACCES;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
if (!bch->readonly)
{
bchlib_semtake(bch);
ret = bchlib_write(bch, buffer, filep->f_pos, len);
if (ret > 0)
{
filep->f_pos += len;
}
bchlib_semgive(bch);
}
return ret;
}
/****************************************************************************
* Name: bch_ioctl
*
* Description:
* Handle IOCTL commands
*
****************************************************************************/
static int bch_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct bchlib_s *bch;
int ret = -ENOTTY;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
/* Process the call according to the command */
switch (cmd)
{
/* This isa request to get the private data structure */
case DIOC_GETPRIV:
{
FAR struct bchlib_s **bchr =
(FAR struct bchlib_s **)((uintptr_t)arg);
bchlib_semtake(bch);
if (!bchr || bch->refs == MAX_OPENCNT)
{
ret = -EINVAL;
}
else
{
bch->refs++;
*bchr = bch;
ret = OK;
}
bchlib_semgive(bch);
}
break;
/* This is a required to return the geometry of the underlying block
* driver.
*/
case BIOC_GEOMETRY:
{
FAR struct geometry *geo = (FAR struct geometry *)((uintptr_t)arg);
DEBUGASSERT(geo != NULL && bch->inode && bch->inode->u.i_bops &&
bch->inode->u.i_bops->geometry);
ret = bch->inode->u.i_bops->geometry(bch->inode, geo);
if (ret < 0)
{
ferr("ERROR: geometry failed: %d\n", -ret);
}
else if (!geo->geo_available)
{
ferr("ERROR: geometry failed: %d\n", -ret);
ret = -ENODEV;
}
}
break;
#ifdef CONFIG_BCH_ENCRYPTION
/* This is a request to set the encryption key? */
case DIOC_SETKEY:
{
memcpy(bch->key, (FAR void *)arg, CONFIG_BCH_ENCRYPTION_KEY_SIZE);
ret = OK;
}
break;
#endif
/* Otherwise, pass the IOCTL command on to the contained block driver. */
default:
{
FAR struct inode *bchinode = bch->inode;
/* Does the block driver support the ioctl method? */
if (bchinode->u.i_bops->ioctl != NULL)
{
ret = bchinode->u.i_bops->ioctl(bchinode, cmd, arg);
}
}
break;
}
return ret;
}
/****************************************************************************
* Name: bch_unlink
*
* Handle unlinking of the BCH device
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int bch_unlink(FAR struct inode *inode)
{
FAR struct bchlib_s *bch;
int ret = OK;
DEBUGASSERT(inode && inode->i_private);
bch = (FAR struct bchlib_s *)inode->i_private;
/* Get exclusive access to the BCH device */
bchlib_semtake(bch);
/* Indicate that the driver has been unlinked */
bch->unlinked = true;
/* If there are no open references to the drvier then teardown the BCH
* device now.
*/
if (bch->refs == 0)
{
/* Tear the driver down now. */
ret = bchlib_teardown((FAR void *)bch);
/* bchlib_teardown() would only fail if there are outstanding
* references on the device. Since we know that is not true, it
* should not fail at all.
*/
DEBUGASSERT(ret >= 0);
if (ret >= 0)
{
/* Return without releasing the stale semaphore */
return OK;
}
}
bchlib_semgive(bch);
return ret;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
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