/****************************************************************************
* arch/arm/src/sam34/sam_timerisr.c
*
* Copyright (C) 2010, 2013-2014 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"
/****************************************************************************
* Definitions
****************************************************************************/
/* Select MCU-specific settings
*
* For the SAM3U, SAM3A, and SAM3X, Systick is driven by the main clock
* (This could be the MCK/8 but that option has not yet been necessary).
* For the SAM4L, SAM4S, and SAM4E, Systick is driven by the CPU clock which
* is just the main clock divided down.
*/
#if defined(CONFIG_ARCH_CHIP_SAM3U) || defined(CONFIG_ARCH_CHIP_SAM3X) || \
defined(CONFIG_ARCH_CHIP_SAM3A)
# define SAM_SYSTICK_CLOCK BOARD_MCK_FREQUENCY /* Frequency of the main clock */
#elif defined(CONFIG_ARCH_CHIP_SAM4L) || defined(CONFIG_ARCH_CHIP_SAM4CM) || \
defined(CONFIG_ARCH_CHIP_SAM4S) || defined(CONFIG_ARCH_CHIP_SAM4E)
# define SAM_SYSTICK_CLOCK BOARD_CPU_FREQUENCY /* CPU frequency */
#else
# error Unrecognized SAM architecture
#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).
*
* The SAM3U feeds the Cortex System Timer (SysTick) with the MCK clock or
* the MCK clock divided by 8, configurable with the CLKSOURCE bit in the
* SysTick Control and Status register.
*/
#undef CONFIG_SAM34_SYSTICK_HCLKd8 /* Power up default is MCK, not MCK/8 */
#if CONFIG_SAM34_SYSTICK_HCLKd8
# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / 8 / CLK_TCK) - 1)
#else
# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / CLK_TCK) - 1)
#endif
/* 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(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);
/* Make sure that the SYSTICK clock source is set correctly */
#if 0 /* Does not work. Comes up with HCLK source and I can't change it */
regval = getreg32(NVIC_SYSTICK_CTRL);
#if CONFIG_SAM34_SYSTICK_HCLKd8
regval &= ~NVIC_SYSTICK_CTRL_CLKSOURCE;
#else
regval |= NVIC_SYSTICK_CTRL_CLKSOURCE;
#endif
putreg32(regval, NVIC_SYSTICK_CTRL);
#endif
/* Configure SysTick to interrupt at the requested rate */
putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD);
putreg32(0, NVIC_SYSTICK_CURRENT);
/* Attach the timer interrupt vector */
(void)irq_attach(SAM_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(SAM_IRQ_SYSTICK);
}
