incubator-nuttx/drivers/ipcc/ipcc_close.c

94 lines
2.8 KiB
C

/****************************************************************************
* drivers/ipcc/ipcc_close.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/ipcc.h>
#include <nuttx/kmalloc.h>
#include <nuttx/semaphore.h>
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#include "ipcc_priv.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipcc_close
*
* Description:
* Closes the driver device. If this is last reference and file has been
* unlinked, we will also free resources allocated by ipcc_register()
*
* Input Parameters:
* filep - pointer to a file structure to close.
*
* Returned Value:
* OK on successfull close, or negated errno on failure.
*
* Assumptions/Limitations:
*
****************************************************************************/
int ipcc_close(FAR struct file *filep)
{
FAR struct ipcc_driver_s *priv;
int ret;
/* Get our private data structure */
priv = filep->f_inode->i_private;
/* Get exclusive access to the IPCC driver state structure */
if ((ret = nxmutex_lock(&priv->lock)) < 0)
{
return ret;
}
/* Decrement the count of open references on the driver */
DEBUGASSERT(priv->crefs > 0);
priv->crefs--;
if (priv->crefs <= 0 && priv->unlinked)
{
/* If count ref is zero and file has been unlinked, it
* means nobody uses the driver and seems like nobody
* wants to use it anymore, so free up resources.
*/
ipcc_cleanup(priv);
return OK;
}
nxmutex_unlock(&priv->lock);
return OK;
}