tkdev_timer.h

使用广泛的日本著名的开源嵌入式实时操作系统T-Kernel的源码

/*
 *----------------------------------------------------------------------
 *    T-Kernel
 *
 *    Copyright (C) 2004-2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel is distributed under the T-License.
 *----------------------------------------------------------------------
 *
 *    Version:   1.02.02
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/9.
 *
 *----------------------------------------------------------------------
 */

/*
 *	tkdev_timer.h (VR4131)
 *	Hardware-Dependent Timer Processing
 */

#ifndef _TKDEV_TIMER_
#define _TKDEV_TIMER_

#include <tk/syslib.h>
#include <sys/sysinfo.h>
#include <tk/sysdef.h>
#include "tkdev_conf.h"

/*
 * Settable interval range (millisecond)
 */
#define MIN_TIMER_PERIOD	1
#define MAX_TIMER_PERIOD	50

/*
 * Set timer
 */
Inline void init_hw_timer( void )
{
	UW	n, imask;

	DI(imask);

	/* Stop timer */
	out_h(TCLKLREG, 0);
	out_h(TCLKHREG, 0);

	/* Counter setting value */
	n = (UW)TIMER_PERIOD * SCInfo.TClock * 10 - 1;

	/* Start timer count */
	out_h(TCLKLREG, n & 0xffff);
	out_h(TCLKHREG, n >> 16);

	EI(imask);
}

/*
 * Timer start processing
 *	Initialize the timer and start the periodical timer interrupt.
 */
Inline void start_hw_timer( void )
{
IMPORT	void	timer_handler_startup( void );

	/* Set timer */
	init_hw_timer();

	/* Interrupt handler definition */
	define_inthdr(VECNO_TCLK, timer_handler_startup);

	/* Timer interrupt enable */
	out_h(RTCINTREG, RTC_TCLK); /* Interrupt clear */
	EnableInt(VECNO_TCLK);
}

/*
 * Clear timer interrupt
 *	Clear the timer interrupt request. Depending on the type of
 *	hardware, there are two timings for clearing: at the beginning
 *	and the end of the interrupt handler.
 *	'clear_hw_timer_interrupt()' is called at the beginning of the
 *	timer interrupt handler.
 *	'end_of_hw_timer_interrupt()' is called at the end of the timer 
 *	interrupt handler.
 *	Use either or both according to hardware.
 */
Inline void clear_hw_timer_interrupt( void )
{
	/* Clear timer interrupt */
	out_h(RTCINTREG, RTC_TCLK);
}
Inline void end_of_hw_timer_interrupt( void )
{
	/* Nothing special */
}

/*
 * Timer stop processing
 *	Stop the timer operation.
 *	Called when system stops.
 */
Inline void terminate_hw_timer( void )
{
	/* Timer interrupt disable */
	DisableInt(VECNO_TCLK);
}

/*
 * Get processing time from the previous timer interrupt to the
 * current (nanosecond)
 *	Consider the possibility that the timer interrupt occurred
 *	during the nterrupt disable and calculate the processing time 
 *	within the following 
 *	range:	0 <= Processing time < TIMER_PERIOD * 2
 */
Inline UINT get_hw_timer_nsec( void )
{
	UW	hi, lo, ofs, max, unf, imask;

	DI(imask);

	max = (((UW)in_h(TCLKHREG) << 16) | in_h(TCLKLREG)) + 1;
	do {
		unf = in_h(RTCINTREG) & RTC_TCLK;
		do {
			hi = in_h(TCLKCNTHREG);
			lo = in_h(TCLKCNTLREG);
		} while ( hi != in_h(TCLKCNTHREG) );
		ofs = max - ((hi << 16) | lo);
	} while ( unf != (in_h(RTCINTREG) & RTC_TCLK) );
	if ( unf != 0 ) {
		ofs += max;
	}

	EI(imask);

	return ofs * 100 / SCInfo.TClock * 1000;
}

#endif /* _TKDEV_TIMER_ */