181 lines
6.4 KiB
C
181 lines
6.4 KiB
C
/****************************************************************************
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* arch/arm/src/sam34/sam_timerisr.c
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*
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* Copyright (C) 2010, 2013-2014 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 <nuttx/config.h>
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#include <stdint.h>
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#include <time.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <arch/board/board.h>
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#include "nvic.h"
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#include "clock/clock.h"
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#include "up_internal.h"
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#include "up_arch.h"
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#include "chip.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Select MCU-specific settings
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*
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* For the SAM3U, SAM3A, and SAM3X, Systick is driven by the main clock
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* (This could be the MCK/8 but that option has not yet been necessary).
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* For the SAM4L, SAM4S, and SAM4E, Systick is driven by the CPU clock which
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* is just the main clock divided down.
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*/
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#if defined(CONFIG_ARCH_CHIP_SAM3U) || defined(CONFIG_ARCH_CHIP_SAM3X) || \
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defined(CONFIG_ARCH_CHIP_SAM3A)
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# define SAM_SYSTICK_CLOCK BOARD_MCK_FREQUENCY /* Frequency of the main clock */
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#elif defined(CONFIG_ARCH_CHIP_SAM4L) || defined(CONFIG_ARCH_CHIP_SAM4CM) || \
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defined(CONFIG_ARCH_CHIP_SAM4S) || defined(CONFIG_ARCH_CHIP_SAM4E)
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# define SAM_SYSTICK_CLOCK BOARD_CPU_FREQUENCY /* CPU frequency */
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#else
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# error Unrecognized SAM architecture
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#endif
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/* The desired timer interrupt frequency is provided by the definition
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* CLK_TCK (see include/time.h). CLK_TCK defines the desired number of
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* system clock ticks per second. That value is a user configurable setting
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* that defaults to 100 (100 ticks per second = 10 MS interval).
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*
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* The SAM3U feeds the Cortex System Timer (SysTick) with the MCK clock or
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* the MCK clock divided by 8, configurable with the CLKSOURCE bit in the
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* SysTick Control and Status register.
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*/
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#undef CONFIG_SAM34_SYSTICK_HCLKd8 /* Power up default is MCK, not MCK/8 */
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#ifdef CONFIG_SAM34_SYSTICK_HCLKd8
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# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / 8 / CLK_TCK) - 1)
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#else
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# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / CLK_TCK) - 1)
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#endif
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/* The size of the reload field is 24 bits. Verify that the reload value
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* will fit in the reload register.
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*/
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#if SYSTICK_RELOAD > 0x00ffffff
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# error SYSTICK_RELOAD exceeds the range of the RELOAD register
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#endif
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Function Prototypes
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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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* Function: up_timerisr
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*
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* Description:
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* The timer ISR will perform a variety of services for various portions
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* of the systems.
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*
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****************************************************************************/
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int up_timerisr(int irq, uint32_t *regs)
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{
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/* Process timer interrupt */
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sched_process_timer();
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return 0;
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}
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/****************************************************************************
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* Function: up_timer_initialize
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*
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* Description:
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* This function is called during start-up to initialize the timer
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* interrupt.
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*
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****************************************************************************/
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void up_timer_initialize(void)
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{
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uint32_t regval;
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/* Set the SysTick interrupt to the default priority */
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regval = getreg32(NVIC_SYSH12_15_PRIORITY);
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regval &= ~NVIC_SYSH_PRIORITY_PR15_MASK;
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regval |= (NVIC_SYSH_PRIORITY_DEFAULT << NVIC_SYSH_PRIORITY_PR15_SHIFT);
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putreg32(regval, NVIC_SYSH12_15_PRIORITY);
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/* Make sure that the SYSTICK clock source is set correctly */
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#if 0 /* Does not work. Comes up with HCLK source and I can't change it */
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regval = getreg32(NVIC_SYSTICK_CTRL);
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#ifdef CONFIG_SAM34_SYSTICK_HCLKd8
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regval &= ~NVIC_SYSTICK_CTRL_CLKSOURCE;
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#else
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regval |= NVIC_SYSTICK_CTRL_CLKSOURCE;
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#endif
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putreg32(regval, NVIC_SYSTICK_CTRL);
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#endif
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/* Configure SysTick to interrupt at the requested rate */
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putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD);
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putreg32(0, NVIC_SYSTICK_CURRENT);
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/* Attach the timer interrupt vector */
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(void)irq_attach(SAM_IRQ_SYSTICK, (xcpt_t)up_timerisr);
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/* Enable SysTick interrupts */
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putreg32((NVIC_SYSTICK_CTRL_CLKSOURCE | NVIC_SYSTICK_CTRL_TICKINT |
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NVIC_SYSTICK_CTRL_ENABLE), NVIC_SYSTICK_CTRL);
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/* And enable the timer interrupt */
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up_enable_irq(SAM_IRQ_SYSTICK);
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}
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