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/****************************************************************************
* arch/arm/src/nuc1xx/nuc_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_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "chip/nuc_clk.h"
#include "chip/nuc_gcr.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Get the frequency of the selected clock source */
#if defined(CONFIG_NUC_SYSTICK_CORECLK)
# define SYSTICK_CLOCK BOARD_HCLK_FREQUENCY /* Core clock */
#elif defined(CONFIG_NUC_SYSTICK_XTALHI)
# define SYSTICK_CLOCK BOARD_XTALHI_FREQUENCY /* High speed XTAL clock */
#elif defined(CONFIG_NUC_SYSTICK_XTALLO)
# define SYSTICK_CLOCK BOARD_XTALLO_FREQUENCY /* Low speed XTAL clock */
#elif defined(CONFIG_NUC_SYSTICK_XTALHId2)
# define SYSTICK_CLOCK (BOARD_XTALHI_FREQUENCY/2) /* High speed XTAL clock/2 */
#elif defined(CONFIG_NUC_SYSTICK_HCLKd2)
# define SYSTICK_CLOCK (BOARD_HCLK_FREQUENCY/2) /* HCLK/2 */
#elif defined(CONFIG_NUC_SYSTICK_INTHId2)
# define SYSTICK_CLOCK (NUC_INTHI_FREQUENCY/2) /* Internal high speed clock/2 */
#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 14-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
****************************************************************************/
/****************************************************************************
* Name: nuc_unlock
*
* Description:
* Unlock registers
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_NUC_SYSTICK_CORECLK
static inline void nuc_unlock(void)
{
putreg32(0x59, NUC_GCR_REGWRPROT);
putreg32(0x16, NUC_GCR_REGWRPROT);
putreg32(0x88, NUC_GCR_REGWRPROT);
}
#endif
/****************************************************************************
* Name: nuclock
*
* Description:
* Lok registers
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_NUC_SYSTICK_CORECLK
static inline void nuc_lock(void)
{
putreg32(0, NUC_GCR_REGWRPROT);
}
#endif
/****************************************************************************
* 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;
/* Configure the SysTick clock source. This is only necessary if we are not
* using the Cortex-M0 core clock as the frequency source.
*/
#ifndef CONFIG_NUC_SYSTICK_CORECLK
/* This field is write protected and must be unlocked */
nuc_unlock();
/* Read the CLKSEL0 register and set the STCLK_S field appropriately */
regval = getreg32(NUC_CLK_CLKSEL0);
regval &= ~CLK_CLKSEL0_STCLK_S_MASK;
#if defined(CONFIG_NUC_SYSTICK_XTALHI)
regval |= CLK_CLKSEL0_STCLK_S_XTALHI; /* High speed XTAL clock */
#elif defined(CONFIG_NUC_SYSTICK_XTALLO)
regval |= CLK_CLKSEL0_STCLK_S_XTALLO; /* Low speed XTAL clock */
#elif defined(CONFIG_NUC_SYSTICK_XTALHId2)
regval |= CLK_CLKSEL0_STCLK_S_XTALDIV2; /* High speed XTAL clock/2 */
#elif defined(CONFIG_NUC_SYSTICK_HCLKd2)
regval |= CLK_CLKSEL0_STCLK_S_HCLKDIV2; /* HCLK/2 */
#elif defined(CONFIG_NUC_SYSTICK_INTHId2)
regval |= CLK_CLKSEL0_STCLK_S_INTDIV2; /* Internal high speed clock/2 */
#endif
putreg32(regval, NUC_CLK_CLKSEL0);
/* Re-lock the register */
nuc_lock();
#endif
/* 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(NUC_IRQ_SYSTICK, (xcpt_t)up_timerisr);
/* Enable SysTick interrupts. We need to select the core clock here if
* we are not using one of the alternative clock sources above.
*/
#ifdef CONFIG_NUC_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(NUC_IRQ_SYSTICK);
}
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