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/****************************************************************************
* arch/arm/src/a1x/a1x_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 <assert.h>
#include <nuttx/arch.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "chip/a1x_timer.h"
/****************************************************************************
* Definitions
****************************************************************************/
/* Timer 0 will run at the rate of OSC24M with no division */
#define TMR0_CLOCK (24000000)
/* 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).
*
* Timer 0 counts down from the interval reload value to zero, generating
* an interrupt (and reload) when the counts decrements to zero.
*/
#define TMR_INTERVAL ((TMR0_CLOCK + (CLK_TCK >> 1)) / CLK_TCK)
/****************************************************************************
* 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)
{
/* Only a TIMER0 interrupt is expected here */
DEBUGASSERT((getreg32(A1X_TMR_IRQ_STA) & TMR_IRQ_TMR0) != 0);
/* Clear the pending interrupt by writing a '1' to the status register */
putreg32(TMR_IRQ_TMR0, A1X_TMR_IRQ_STA);
/* Process timer interrupt */
sched_process_timer();
return OK;
}
/****************************************************************************
* 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 timer reload interval value */
putreg32(TMR_INTERVAL, A1X_TMR0_INTV_VALUE);
/* Configure timer 0:
*
* ENABLE - Enable counting
* RELOAD - Reload timer interval value
* CLKSRC - OSC24M
* PRESCALER - No division
* MODE - Continuous mode
*/
regval = (TMR_CTRL_EN | TMR_CTRL_RELOAD | TMR_CTRL_SRC_OSC24M |
TMR_CTRL_CLK_PRES_DIV1 | TMR_CTRL_MODE_CONTINUOUS);
putreg32(regval, A1X_TMR0_CTRL);
/* Make sure that interrupts from the Timer 0 are disabled */
up_disable_irq(A1X_IRQ_TIMER0);
/* Attach the timer interrupt vector */
(void)irq_attach(A1X_IRQ_TIMER0, (xcpt_t)up_timerisr);
/* Enable interrupts from the TIMER 0 port */
regval = getreg32(A1X_TMR_IRQ_EN);
regval |= TMR_IRQ_TMR0;
putreg32(regval, A1X_TMR_IRQ_EN);
/* And enable the timer interrupt */
up_enable_irq(A1X_IRQ_TIMER0);
}
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