sa1100-timer.c

rtai-3.1-test3的源代码(Real-Time Application Interface )

/* rtai/arch/arm/mach-sa1100/timer.c
COPYRIGHT (C) 2002 Guennadi Liakhovetski, DSA GmbH ([e-mail])
COPYRIGHT (C) 2002 Wolfgang M黮ler ([e-mail])
Copyright (c) 2001 Alex Z黳ke, SYSGO RTS GmbH ([e-mail])

This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License as
published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
--------------------------------------------------------------------------
Acknowledgements
- Paolo Mantegazza	([e-mail])
	creator of RTAI 
*/

#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/mach/irq.h>
#include <asm/system.h>
#include <rtai.h>
#include <rtai_trace.h>

void rtai_sa1100_GPIO11_27_demux( int irq, void *dev_id, struct pt_regs *regs )
{
	sa1100_GPIO11_27_demux( IRQ_GPIO11_27, dev_id, regs );
	/* No pending to linux! */
}

/*
 * hacked from linux/include/asm-arm/arch-sa1100/time.h
 * static void sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 */
static void linux_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	long flags;
	int next_match;

	do {
		//do_leds();
		save_flags_cli(flags);
		do_timer(regs);
		OSSR = OSSR_M0;
		next_match = (OSMR0 += LATCH);
		rthal.timer_match = next_match;
		restore_flags(flags);
	} while((signed long)(next_match - OSCR) <= 0);
}

void soft_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	long flags;

	rdtsc(); /* update tsc - make sure we don't miss a wrap */
	//do_leds();
	save_flags_cli(flags);
	do_timer(regs);
	rthal.timer_match = OSCR + LATCH;
	restore_flags(flags);
}

void rt_request_timer(void (*handler)(void), unsigned int tick, int unused)
{
	RTIME t;
	unsigned long flags;

	TRACE_RTAI_TIMER(TRACE_RTAI_EV_TIMER_REQUEST, handler, tick);
	flags = hard_lock_all();
/*
 * sync w/jiffie, wait for a OS timer 0 match and clear the match bit
 */
	rtai_tsc.tsc = 0;
	/* wait for a timer match 0 and clear the match bit */
	do {
	} while ( (signed long)(OSMR0 - OSCR) >= 0 );
        OSSR = OSSR_M0;

	/* set up rt_times structure */
	rt_times.linux_tick = LATCH;
	rt_times.periodic_tick = tick > 0 && tick < (RTIME)rt_times.linux_tick ? tick : rt_times.linux_tick;
	rt_times.tick_time  = t = rdtsc();
	rt_times.intr_time  = t + (RTIME)rt_times.periodic_tick;
	rt_times.linux_time = t + (RTIME)rt_times.linux_tick;

	/* Trick the scheduler - set this our way. */
//	tuned.setup_time_TIMER_CPUNIT = (int)(~(~0 >> 1)) + 1; /* smallest negative + 1 - for extra safety:-) */

	/* update Match-register */
	rt_set_timer_match_reg(rt_times.periodic_tick);

	irq_desc[TIMER_8254_IRQ].action->handler = soft_timer_interrupt;

	rt_free_global_irq(TIMER_8254_IRQ);
	rt_request_global_irq(TIMER_8254_IRQ, handler);

/*
 * pend linux timer irq to handle current jiffie 
 */
 	rt_pend_linux_irq(TIMER_8254_IRQ);
 
	hard_unlock_all(flags);

	return;
}

void rt_free_timer(void)
{
	unsigned long flags;

	TRACE_RTAI_TIMER(TRACE_RTAI_EV_TIMER_FREE, 0, 0);

	flags = hard_lock_all();

	rt_free_global_irq(TIMER_8254_IRQ);
	irq_desc[TIMER_8254_IRQ].action->handler = linux_timer_interrupt;

	hard_unlock_all(flags);
}