130 lines
4.3 KiB
C
130 lines
4.3 KiB
C
/****************************************************************************
|
|
* nuttx/graphics/nxconsole/nxcon_sem.c
|
|
*
|
|
* Copyright (C) 2012 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 <unistd.h>
|
|
#include <semaphore.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
#include "nxcon_internal.h"
|
|
|
|
#ifdef CONFIG_DEBUG
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Function Prototypes
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Data
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxcon_semwait and nxcon_sempost
|
|
*
|
|
* Description:
|
|
* If debug is on, then lower level code may attempt console output while
|
|
* we are doing console output! In this case, we will toss the nested
|
|
* output to avoid deadlocks and infinite loops.
|
|
*
|
|
* Input Parameters:
|
|
* priv - Driver data structure
|
|
*
|
|
* Returned Value:
|
|
*
|
|
*
|
|
****************************************************************************/
|
|
|
|
int nxcon_semwait(FAR struct nxcon_state_s *priv)
|
|
{
|
|
pid_t me;
|
|
int ret;
|
|
|
|
/* Does I already hold the semaphore */
|
|
|
|
me = getpid();
|
|
if (priv->holder != me)
|
|
{
|
|
/* No.. then wait until the thread that does hold it is finished with it */
|
|
|
|
ret = sem_wait(&priv->exclsem);
|
|
if (ret == OK)
|
|
{
|
|
/* No I hold the semaphore */
|
|
|
|
priv->holder = me;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Abort, abort, abort! I have been re-entered */
|
|
|
|
set_errno(EBUSY);
|
|
return ERROR;
|
|
}
|
|
|
|
int nxcon_sempost(FAR struct nxcon_state_s *priv)
|
|
{
|
|
pid_t me = getpid();
|
|
|
|
/* Make sure that I really hold the semaphore */
|
|
|
|
ASSERT(priv->holder == me);
|
|
|
|
/* Then let go of it */
|
|
|
|
priv->holder = NO_HOLDER;
|
|
return sem_post(&priv->exclsem);
|
|
}
|
|
|
|
#endif /* CONFIG_DEBUG */
|