/****************************************************************************
* arch/sh/src/m16c/m16c_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 <sys/types.h>
#include <time.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "clock_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "m16c_timer.h"
/****************************************************************************
* Preprocessor Definitions
****************************************************************************/
/* Configuration */
#ifndef M16C_TA0_PRIO /* Timer A0 interrupt priority */
# define M16C_TA0_PRIO 5
#endif
/* Determine the ideal preload value for the timer.
*
* For example, given a 20MHz input frequency and a desired 100 Hz, clock,
* the ideal reload value would be:
*
* 20,000,000 / 100 = 200,000
*
* The ideal prescaler value would be the one, then that drops this to exactly
* 66535:
*
* M16C_IDEAL_PRESCALER = 200,000 / 65535 = 3.05
*
* And any value greater than 3.05 would also work with less and less precision.
* The following calculation will produce the ideal prescaler as the next integer
* value above any fractional values:
*/
#define M16C_DIVISOR (65535 * CLK_TCK)
#define M16C_IDEAL_PRESCALER \
((M16C_XIN_FREQ + M16C_DIVISOR - 1) / M16C_DIVISOR)
/* Now, given this idel prescaler value, pick between available choices: 1, 8, and 32 */
#if M16C_IDEAL_PRESCALER > 8
# define M16C_PRESCALE_VALUE 32
# define M16C_PRESCALE_BITS TAnMR_TCK_TMF32
#elif M16C_IDEL_PRESCALER > 1
# define M16C_PRESCALE_VALUE 8
# define M16C_PRESCALE_BITS TAnMR_TCK_TMF8
#else
# define M16C_PRESCALE_VALUE 1
# define M16C_PRESCALE_BITS TAnMR_TCK_TMF1
#endif
/* Timer 0 Mode Settings */
#define M16C_TA0MODE_CONFIG \
(TAnMR_TMOD_TIMER|TAnMR_MR_TMNOOUT|TAnMR_MR_TMNOGATE|M16C_PRESCALE_BITS)
/* The actual reload value matching the selected prescaler value */
#define M16C_RELOAD_VALUE \
((M16C_XIN_FREQ / M16C_PRESCALE_VALUE / CLK_TCK) - 1)
/****************************************************************************
* Private Type Definitions
****************************************************************************/
/****************************************************************************
* 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 *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)
{
/* Make sure that no timers are running and that all timer interrupts are
* disabled.
*/
putreg8(0, M16C_TABSR);
putreg8(0, M16C_TA0IC);
putreg8(0, M16C_TA1IC);
putreg8(0, M16C_TA2IC);
putreg8(0, M16C_TA3IC);
putreg8(0, M16C_TA4IC);
putreg8(0, M16C_TB0IC);
putreg8(0, M16C_TB1IC);
putreg8(0, M16C_TB2IC);
/* Set up timer 0 mode register for timer mode with the calculated prescaler value */
putreg8(M16C_TA0MODE_CONFIG, M16C_TA0MR);
/* Set the calculated reload value */
putreg16(M16C_RELOAD_VALUE, M16C_TA0);
/* Attach the interrupt handler */
irq_attach(M16C_SYSTIMER_IRQ, (xcpt_t)up_timerisr);
/* Enable timer interrupts */
putreg8(1, M16C_TA0IC);
/* Set the interrupt priority */
putreg8(M16C_TA0_PRIO, M16C_TA0IC);
/* Start the timer */
putreg8(TABSR_TA0S, M16C_TABSR);
}
