110 lines
4 KiB
C
110 lines
4 KiB
C
![]() |
/************************************************************
|
||
|
* sched_lock.c
|
||
|
*
|
||
|
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
|
||
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
||
|
*
|
||
|
* 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 Gregory Nutt 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 <sched.h>
|
||
|
#include <assert.h>
|
||
|
#include <nuttx/arch.h>
|
||
|
#include "os_internal.h"
|
||
|
|
||
|
/************************************************************
|
||
|
* Definitions
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Private Type Declarations
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Global Variables
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Private Variables
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Private Function Prototypes
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Private Functionss
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Public Functions
|
||
|
************************************************************/
|
||
|
|
||
|
/************************************************************
|
||
|
* Name: sched_lock
|
||
|
*
|
||
|
* Description:
|
||
|
* This function disables context switching by disabling
|
||
|
* addition of new tasks to the g_readytorun task list.
|
||
|
* The task that calls this function will be the only task
|
||
|
* that is allowed to run until it either calls
|
||
|
* sched_unlock() (the appropriate number of times) or
|
||
|
* until it blocks itself.
|
||
|
*
|
||
|
* Inputs
|
||
|
* None
|
||
|
*
|
||
|
* Return Value:
|
||
|
* OK on success; ERROR on failure
|
||
|
*
|
||
|
************************************************************/
|
||
|
|
||
|
STATUS sched_lock(void)
|
||
|
{
|
||
|
_TCB *rtcb = (_TCB*)g_readytorun.head;
|
||
|
|
||
|
/* Check for some special cases: (1) rtcb may be NULL only during
|
||
|
* early boot-up phases, and (2) sched_lock() should have no
|
||
|
* effect if called from the interrupt level.
|
||
|
*/
|
||
|
|
||
|
if (rtcb && !up_interrupt_context())
|
||
|
{
|
||
|
ASSERT(rtcb->lockcount < MAX_LOCK_COUNT);
|
||
|
rtcb->lockcount++;
|
||
|
}
|
||
|
return OK;
|
||
|
}
|