96 lines
4.0 KiB
C
96 lines
4.0 KiB
C
/****************************************************************************
|
|
* arch/xtensa/src/common/xtensa_idle.c
|
|
*
|
|
* Copyright (C) 2016 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/irq.h>
|
|
#include <nuttx/arch.h>
|
|
|
|
#include "xtensa.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: up_idle
|
|
*
|
|
* Description:
|
|
* up_idle() is the logic that will be executed when their is no other
|
|
* ready-to-run task. This is processor idle time and will continue until
|
|
* some interrupt occurs to cause a context switch from the idle task.
|
|
*
|
|
* Processing in this state may be processor-specific. e.g., this is where
|
|
* power management operations might be performed.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void up_idle(void)
|
|
{
|
|
#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_TIMER_INTS)
|
|
/* If the system is idle and there are no timer interrupts, then process
|
|
* "fake" timer interrupts. Hopefully, something will wake up.
|
|
*/
|
|
|
|
sched_process_timer();
|
|
#else
|
|
|
|
/* This would be an appropriate place to put some MCU-specific logic to
|
|
* sleep in a reduced power mode until an interrupt occurs to save power
|
|
*/
|
|
|
|
/* This is a kludge that I still don't understand. The call to kmm_trysemaphore()
|
|
* in the os_start.c IDLE loop seems necessary for the good health of the IDLE
|
|
* loop. When the work queue is enabled, this logic is removed from the IDLE
|
|
* loop and it appears that we are somehow left idling with interrupts non-
|
|
* functional. The following should be no-op, it just disables then re-enables
|
|
* interrupts. But it fixes the problem and will stay here until I understand
|
|
* the problem/fix better.
|
|
*
|
|
* And no, the contents of the CP0 status register are not incorrect. But for
|
|
* some reason the status register needs to be re-written again on this thread
|
|
* for it to take effect. This might be a PIC32-only issue?
|
|
*/
|
|
|
|
#ifdef CONFIG_SCHED_WORKQUEUE
|
|
irqstate_t flags = enter_critical_section();
|
|
leave_critical_section(flags);
|
|
#endif
|
|
#endif
|
|
}
|