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/****************************************************************************
* arch/arm/src/lm3s/lm3s_timerisr.c
*
* Copyright (C) 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <stdint.h>
#include <time.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "nvic.h"
#include "clock_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "lm3s_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* The desired timer interrupt frequency is provided by the definition
* CLK_TCK (see include/time.h). CLK_TCK defines the desired number of
* system clock ticks per second. That value is a user configurable setting
* that defaults to 100 (100 ticks per second = 10 MS interval).
*
* The timer counts at the rate SYSCLK_FREQUENCY as defined in the board.h
* header file.
*/
#define SYSTICK_RELOAD ((SYSCLK_FREQUENCY / CLK_TCK) - 1)
/* The size of the reload field is 24 bits. Verify taht the reload value
* will fit in the reload register.
*/
#if SYSTICK_RELOAD > 0x00ffffff
# error SYSTICK_RELOAD exceeds the range of the RELOAD register
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Function: up_timerisr
*
* Description:
* The timer ISR will perform a variety of services for various portions
* of the systems.
*
****************************************************************************/
int up_timerisr(int irq, uint32_t *regs)
{
/* Process timer interrupt */
sched_process_timer();
return 0;
}
/****************************************************************************
* Function: up_timerinit
*
* Description:
* This function is called during start-up to initialize
* the timer interrupt.
*
****************************************************************************/
void up_timerinit(void)
{
uint32_t regval;
/* Set the SysTick interrupt to the default priority */
regval = getreg32(NVIC_SYSH12_15_PRIORITY);
regval &= ~NVIC_SYSH_PRIORITY_PR15_MASK;
regval |= (NVIC_SYSH_PRIORITY_DEFAULT << NVIC_SYSH_PRIORITY_PR15_SHIFT);
putreg32(regval, NVIC_SYSH12_15_PRIORITY);
/* Configure SysTick to interrupt at the requested rate */
putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD);
/* Attach the timer interrupt vector */
(void)irq_attach(LM3S_IRQ_SYSTICK, (xcpt_t)up_timerisr);
/* Enable SysTick interrupts */
putreg32((NVIC_SYSTICK_CTRL_CLKSOURCE|NVIC_SYSTICK_CTRL_TICKINT|NVIC_SYSTICK_CTRL_ENABLE), NVIC_SYSTICK_CTRL);
/* And enable the timer interrupt */
up_enable_irq(LM3S_IRQ_SYSTICK);
}
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