143 lines
4.6 KiB
C
143 lines
4.6 KiB
C
/****************************************************************************
|
|
* sched/irq/irq_csection.c
|
|
*
|
|
* Copyright (C) 2007-2008, 2010 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 <nuttx/spinlock.h>
|
|
#include <arch/irq.h>
|
|
|
|
#include "sched/sched.h"
|
|
#include "irq/irq.h"
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/****************************************************************************
|
|
* Public Data
|
|
****************************************************************************/
|
|
/* This is the spinlock that enforces critical sections when interrupts are
|
|
* disabled.
|
|
*/
|
|
|
|
spinlock_t g_cpu_irqlock = SP_UNLOCKED;
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: enter_critical_section
|
|
*
|
|
* Description:
|
|
* Take the CPU IRQ lock and disable interrupts on all CPUs. A thread-
|
|
* specific counter is increment to indicate that the thread has IRQs
|
|
* disabled and to support nested calls to enter_critical_section().
|
|
*
|
|
****************************************************************************/
|
|
|
|
irqstate_t enter_critical_section(void)
|
|
{
|
|
FAR struct tcb_s *rtcb = this_task();
|
|
|
|
/* Do we already have interrupts disabled? */
|
|
|
|
if (rtcb->irqcount > 0)
|
|
{
|
|
/* Yes... make sure that the spinlock is set and increment the IRQ
|
|
* lock count.
|
|
*/
|
|
|
|
DEBUGASSERT(g_cpu_irqlock == SP_LOCKED && rtcb->irqcount < INT16_MAX);
|
|
rtcb->irqcount++;
|
|
}
|
|
else
|
|
{
|
|
/* NO.. Take the spinlock to get exclusive access and set the lock
|
|
* count to 1.
|
|
*/
|
|
|
|
spin_lock(&g_cpu_irqlock);
|
|
rtcb->irqcount = 1;
|
|
}
|
|
|
|
/* Then disable interrupts (if they have not already been disabeld) */
|
|
|
|
return irqsave();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: leave_critical_section
|
|
*
|
|
* Description:
|
|
* Decrement the IRQ lock count and if it decrements to zero then release
|
|
* the spinlock.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void leave_critical_section(irqstate_t flags)
|
|
{
|
|
FAR struct tcb_s *rtcb = this_task();
|
|
|
|
DEBUGASSERT(rtcb->irqcount > 0);
|
|
|
|
/* Will we still have interrupts disabled after decrementing the count? */
|
|
|
|
if (rtcb->irqcount > 1)
|
|
{
|
|
/* Yes... make sure that the spinlock is set */
|
|
|
|
DEBUGASSERT(g_cpu_irqlock == SP_LOCKED);
|
|
rtcb->irqcount--;
|
|
}
|
|
else
|
|
{
|
|
/* NO.. Take the spinlock to get exclusive access. */
|
|
|
|
rtcb->irqcount = 0;
|
|
spin_unlock(g_cpu_irqlock);
|
|
}
|
|
|
|
/* Restore the previous interrupt state which may still be interrupts
|
|
* disabled (but we don't have a mechanism to verify that now)
|
|
*/
|
|
|
|
irqrestore(flags);
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|