incubator-nuttx/drivers/ipcc/ipcc_open.c

81 lines
2.4 KiB
C

/****************************************************************************
* drivers/ipcc/ipcc_open.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 <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#include "ipcc_priv.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipcc_open
*
* Description:
* Opens driver for use by userspace applications.
*
* Input Parameters:
* filep - pointer to a file structure to open.
*
* Returned Value:
* OK on successfull open, or negated errno on failure.
*
* Assumptions/Limitations:
*
****************************************************************************/
int ipcc_open(FAR struct file *filep)
{
FAR struct ipcc_driver_s *priv;
int ret;
/* Get our private data structure */
DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
priv = filep->f_inode->i_private;
/* Get exclusive access to the IPCC driver state structure */
if ((ret = nxsem_wait(&priv->exclsem)) < 0)
{
return ret;
}
/* Increment the count of open references on the driver */
priv->crefs++;
DEBUGASSERT(priv->crefs > 0);
nxsem_post(&priv->exclsem);
return OK;
}