base/include/asm-arm/arch-pxa/rtai_timer.h

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/* 020222 asm-arm/arch-pxa/timer.h - ARM/PXA255 specific timer
Don't include directly - it's included through asm-arm/rtai.h

Copyright (c) 2005 Luca Pizzi, (lucapizzi@hotmail.com)
Copyright (c) 2005 Stefano Gafforelli, (stefano.gafforelli@tiscali.it)
COPYRIGHT (C) 2002 Guennadi Liakhovetski, DSA GmbH (gl@dsa-ac.de)
COPYRIGHT (C) 2002 Wolfgang Müller (wolfgang.mueller@dsa-ac.de)
Copyright (c) 2001 Alex Züpke, SYSGO RTS GmbH (azu@sysgo.de)

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  (mantegazza@aero.polimi.it)
    creator of RTAI 
*/

#ifndef _ASM_ARCH_RTAI_TIMER_H_
#define _ASM_ARCH_RTAI_TIMER_H_

//#include <asm/proc/hard_system.h>
#include <linux/time.h>
#include <linux/timer.h>
#include <asm/mach/irq.h>
#include <linux/timex.h>


static inline int rtai_timer_irq_ack( void )
{
    OSSR = OSSR_M0;
    rt_unmask_irq(RTAI_TIMER_IRQ);
    if ( (int)(OSCR - OSMR0) < 0 )
        /* This is what just happened: we were setting a next timer interrupt
           in the scheduler, while a previously configured timer-interrupt
           happened, so, just restore the correct value of the match register and
           proceed as usual. Yes, we will have to re-calculate the next interrupt. */
        OSMR0 = OSCR - 1;
    return 0;
}

union rtai_tsc {
    unsigned long long tsc;
    unsigned long hltsc[2];
};
extern volatile union rtai_tsc rtai_tsc;

static inline RTIME rtai_rdtsc(void)
{
    RTIME ts;
    unsigned long flags, count;

    rtai_save_flags_and_cli(flags);

    if ( ( count = OSCR ) < rtai_tsc.hltsc[0] )
        rtai_tsc.hltsc[1]++;
    rtai_tsc.hltsc[0] = count;
    ts = rtai_tsc.tsc;
    rtai_restore_flags(flags);

    return ts;
}

#define PROTECT_TIMER


/* Current version */
static inline void rt_set_timer_match_reg(int delay)
{
    unsigned long flags;
    unsigned long next_match;

#ifdef PROTECT_TIMER
    if ( delay > LATCH )
        delay = LATCH;
#endif

    rtai_save_flags_and_cli(flags);

    if ( delay )
        next_match = OSMR0 = delay + OSCR;
//      next_match = OSMR0 = delay + rtai_tsc.hltsc[0];
    else
        next_match = ( OSMR0 += rt_times.periodic_tick );
//      next_match = OSMR0 = ((unsigned long *)&rt_times.intr_time)[0];

#ifdef PROTECT_TIMER
    while ((int)(next_match - OSCR) < 2 * SETUP_TIME_TICKS ) {
        OSSR = OSSR_M0;  /* Clear match on timer 0 */
        next_match = OSMR0 = OSCR + 4 * SETUP_TIME_TICKS;
    }
#endif

    rtai_restore_flags(flags);
}
#endif

#define rt_set_timer_delay(x)  rt_set_timer_match_reg(x)

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