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/****************************************************************************
* arch/arm/src/kl/kl_timerisr.c
*
* Copyright (C) 2013 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 <stdint.h>
#include <time.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "nvic.h"
#include "clock/clock.h"
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* "The CLKSOURCE bit in SysTick Control and Status register selects either
* the core clock (when CLKSOURCE = 1) or a divide-by-16 of the core clock
* (when CLKSOURCE = 0). ..."
*/
#if defined(CONFIG_KL_SYSTICK_CORECLK)
# define SYSTICK_CLOCK BOARD_CORECLK_FREQ /* Core clock */
#elif defined(CONFIG_KL_SYSTICK_CORECLK_DIV16)
# define (SYSTICK_CLOCK BOARD_CORECLK_FREQ / 16) /* Core clock divided by 16 */
#endif
/* 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).
*
* Then, for example, if the external high speed crystal is the SysTick
* clock source and BOARD_XTALHI_FREQUENCY is 12MHz and CLK_TCK is 100, then
* the reload value would be:
*
* SYSTICK_RELOAD = (12,000,000 / 100) - 1
* = 119,999
* = 0x1d4bf
*
* Which fits within the maximum 24-bit reload value.
*/
#define SYSTICK_RELOAD ((SYSTICK_CLOCK / CLK_TCK) - 1)
/* The size of the reload field is 24 bits. Verify that 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_timer_initialize
*
* Description:
* This function is called during start-up to initialize
* the timer interrupt.
*
****************************************************************************/
void up_timer_initialize(void)
{
uint32_t regval;
/* Set the SysTick interrupt to the default priority */
regval = getreg32(ARMV6M_SYSCON_SHPR3);
regval &= ~SYSCON_SHPR3_PRI_15_MASK;
regval |= (NVIC_SYSH_PRIORITY_DEFAULT << SYSCON_SHPR3_PRI_15_SHIFT);
putreg32(regval, ARMV6M_SYSCON_SHPR3);
/* Configure SysTick to interrupt at the requested rate */
putreg32(SYSTICK_RELOAD, ARMV6M_SYSTICK_RVR);
/* Attach the timer interrupt vector */
(void)irq_attach(KL_IRQ_SYSTICK, (xcpt_t)up_timerisr);
/* Enable SysTick interrupts. "The CLKSOURCE bit in SysTick Control and
* Status register selects either the core clock (when CLKSOURCE = 1) or
* a divide-by-16 of the core clock (when CLKSOURCE = 0). ..."
*/
#ifdef CONFIG_KL_SYSTICK_CORECLK
putreg32((SYSTICK_CSR_CLKSOURCE | SYSTICK_CSR_TICKINT | SYSTICK_CSR_ENABLE),
ARMV6M_SYSTICK_CSR);
#else
putreg32((SYSTICK_CSR_TICKINT | SYSTICK_CSR_ENABLE), ARMV6M_SYSTICK_CSR);
#endif
/* And enable the timer interrupt */
up_enable_irq(KL_IRQ_SYSTICK);
}
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