121 lines
4.6 KiB
C
121 lines
4.6 KiB
C
/****************************************************************************
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* arch/arm/src/lpc17/lpc17_idle.c
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*
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* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <arch/board/board.h>
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#include <nuttx/config.h>
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#include <nuttx/arch.h>
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#include "up_internal.h"
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#include "lpc17_gpdma.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Does the board support an IDLE LED to indicate that the board is in the
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* IDLE state?
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*/
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#if defined(CONFIG_ARCH_LEDS) && defined(LED_IDLE)
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# define BEGIN_IDLE() board_led_on(LED_IDLE)
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# define END_IDLE() board_led_off(LED_IDLE)
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#else
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# define BEGIN_IDLE()
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# define END_IDLE()
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#endif
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_idle
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*
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* Description:
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* up_idle() is the logic that will be executed when their is no other
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* ready-to-run task. This is processor idle time and will continue until
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* some interrupt occurs to cause a context switch from the idle task.
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*
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* Processing in this state may be processor-specific. e.g., this is where
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* power management operations might be performed.
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*
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****************************************************************************/
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void up_idle(void)
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{
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#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_TIMER_INTS)
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/* If the system is idle and there are no timer interrupts, then process
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* "fake" timer interrupts. Hopefully, something will wake up.
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*/
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sched_process_timer();
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#else
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/* If the g_dma_inprogress is zero, then there is no DMA in progress. This
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* value is needed in the IDLE loop to determine if the IDLE loop should
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* go into lower power power consumption modes. According to the LPC17xx
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* User Manual: "The DMA controller can continue to work in Sleep mode, and
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* has access to the peripheral SRAMs and all peripheral registers. The
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* flash memory and the Main SRAM are not available in Sleep mode, they are
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* disabled in order to save power."
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*/
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#ifdef CONFIG_LPC17_GPDMA
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if (g_dma_inprogress == 0)
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#endif
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{
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/* Sleep until an interrupt occurs in order to save power */
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BEGIN_IDLE();
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asm("WFI");
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END_IDLE();
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}
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#endif
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}
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