/****************************************************************************
 *  arch/arm/src/lpc17/lpc17_idle.c
 *
 *   Copyright (C) 2011-2012 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 <arch/board/board.h>
#include <nuttx/config.h>

#include <nuttx/arch.h>

#include "up_internal.h"
#include "lpc17_gpdma.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/* Does the board support an IDLE LED to indicate that the board is in the
 * IDLE state?
 */

#if defined(CONFIG_ARCH_LEDS) && defined(LED_IDLE)
#  define BEGIN_IDLE() up_ledon(LED_IDLE)
#  define END_IDLE()   up_ledoff(LED_IDLE)
#else
#  define BEGIN_IDLE()
#  define END_IDLE()
#endif

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * 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

/* If the g_dma_inprogress is zero, then there is no DMA in progress.  This
 * value is needed in the IDLE loop to determine if the IDLE loop should
 * go into lower power power consumption modes.  According to the LPC17xx
 * User Manual: "The DMA controller can continue to work in Sleep mode, and
 * has access to the peripheral SRAMs and all peripheral registers. The
 * flash memory and the Main SRAM are not available in Sleep mode, they are
 * disabled in order to save power."
 */

#ifdef CONFIG_LPC17_GPDMA
  if (g_dma_inprogress == 0)
#endif
    {
      /* Sleep until an interrupt occurs in order to save power */

      BEGIN_IDLE();
      asm("WFI");
      END_IDLE();
    }
#endif
}