arm/iomd/iomd_clock.c

/*	$NetBSD: iomd_clock.c,v 1.3 2001/11/23 19:21:48 thorpej Exp $	*/

/*
 * Copyright (c) 1994-1997 Mark Brinicombe.
 * Copyright (c) 1994 Brini.
 * All rights reserved.
 *
 * This code is derived from software written for Brini by Mark Brinicombe
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Mark Brinicombe.
 * 4. The name of the company nor the name of the author may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * RiscBSD kernel project
 *
 * clock.c
 *
 * Timer related machine specific code
 *
 * Created      : 29/09/94
 */

/* Include header files */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/device.h>

#include <machine/irqhandler.h>

#include <arm/cpufunc.h>

#include <arm/iomd/iomdvar.h>
#include <arm/iomd/iomdreg.h>

struct clock_softc {
	struct device 		sc_dev;
	bus_space_tag_t		sc_iot;
	bus_space_handle_t	sc_ioh;
};

#define TIMER_FREQUENCY 2000000		/* 2MHz clock */
#define TICKS_PER_MICROSECOND (TIMER_FREQUENCY / 1000000)

static void *clockirq;
static void *statclockirq;
static struct clock_softc *clock_sc;
static int timer0_count;

static int clockmatch	__P((struct device *parent, struct cfdata *cf, void *aux));
static void clockattach	__P((struct device *parent, struct device *self, void *aux));
#ifdef DIAGNOSTIC
static void checkdelay	__P((void));
#endif

struct cfattach clock_ca = {
	sizeof(struct clock_softc), clockmatch, clockattach
};

/*
 * int clockmatch(struct device *parent, void *match, void *aux)
 *
 * Just return ok for this if it is device 0
 */

static int
clockmatch(parent, cf, aux)
	struct device *parent;
	struct cfdata *cf;
	void *aux;
{
	struct clk_attach_args *ca = aux;

	if (strcmp(ca->ca_name, "clk") == 0)
		return(1);
	return(0);
}


/*
 * void clockattach(struct device *parent, struct device *dev, void *aux)
 *
 * Map the IOMD and identify it.
 * Then configure the child devices based on the IOMD ID.
 */

static void
clockattach(parent, self, aux)
	struct device *parent;
	struct device *self;
	void *aux;
{
	struct clock_softc *sc = (struct clock_softc *)self;
	struct clk_attach_args *ca = aux;

	sc->sc_iot = ca->ca_iot;
	sc->sc_ioh = ca->ca_ioh; /* This is a handle for the whole IOMD */

	clock_sc = sc;

	/* Cannot do anything until cpu_initclocks() has been called */

	printf("\n");
}


/*
 * int clockhandler(struct clockframe *frame)
 *
 * Function called by timer 0 interrupts. This just calls
 * hardclock(). Eventually the irqhandler can call hardclock() directly
 * but for now we use this function so that we can debug IRQ's
 */

int
clockhandler(frame)
	struct clockframe *frame;
{
	hardclock(frame);
	return(0);	/* Pass the interrupt on down the chain */
}


/*
 * int statclockhandler(struct clockframe *frame)
 *
 * Function called by timer 1 interrupts. This just calls
 * statclock(). Eventually the irqhandler can call statclock() directly
 * but for now we use this function so that we can debug IRQ's
 */

int
statclockhandler(frame)
	struct clockframe *frame;
{
	statclock(frame);
	return(0);	/* Pass the interrupt on down the chain */
}


/*
 * void setstatclockrate(int hz)
 *
 * Set the stat clock rate. The stat clock uses timer1
 */

void
setstatclockrate(hz)
	int hz;
{
	int count;

	count = TIMER_FREQUENCY / hz;

	printf("Setting statclock to %dHz (%d ticks)\n", hz, count);

	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T1LOW, (count >> 0) & 0xff);
	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T1HIGH, (count >> 8) & 0xff);

	/* reload the counter */

	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T1GO, 0);
}


#ifdef DIAGNOSTIC
static void
checkdelay()
{
	struct timeval start, end, diff;

	microtime(&start);
	delay(10000);
	microtime(&end);
	timersub(&end, &start, &diff);
	if (diff.tv_sec > 0)
		return;
	if (diff.tv_usec > 10000)
		return;
	printf("WARNING: delay(10000) took %ld us\n", diff.tv_usec);
}
#endif

/*
 * void cpu_initclocks(void)
 *
 * Initialise the clocks.
 * This sets up the two timers in the IOMD and installs the IRQ handlers
 *
 * NOTE: Currently only timer 0 is setup and the IRQ handler is not installed
 */

void
cpu_initclocks()
{
	/*
	 * Load timer 0 with count down value
	 * This timer generates 100Hz interrupts for the system clock
	 */

	printf("clock: hz=%d stathz = %d profhz = %d\n", hz, stathz, profhz);

	timer0_count = TIMER_FREQUENCY / hz;

	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0LOW, (timer0_count >> 0) & 0xff);
	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0HIGH, (timer0_count >> 8) & 0xff);

	/* reload the counter */

	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0GO, 0);

	clockirq = intr_claim(IRQ_TIMER0, IPL_CLOCK, "tmr0 hard clk",
	    clockhandler, 0);

	if (clockirq == NULL)
		panic("%s: Cannot installer timer 0 IRQ handler\n",
		    clock_sc->sc_dev.dv_xname);

	if (stathz) {
		setstatclockrate(stathz);
       		statclockirq = intr_claim(IRQ_TIMER1, IPL_CLOCK,
       		    "tmr1 stat clk", statclockhandler, 0);
		if (statclockirq == NULL)
			panic("%s: Cannot installer timer 1 IRQ handler\n",
			    clock_sc->sc_dev.dv_xname);
	}
#ifdef DIAGNOSTIC
	checkdelay();
#endif
}


/*
 * void microtime(struct timeval *tvp)
 *
 * Fill in the specified timeval struct with the current time
 * accurate to the microsecond.
 */

void
microtime(tvp)
	struct timeval *tvp;
{
	int s;
	int tm;
	int deltatm;
	static struct timeval oldtv;

	if (timer0_count == 0)
		return;

	s = splhigh();

	/*
	 * Latch the current value of the timer and then read it.
	 * This garentees an atmoic reading of the time.
	 */

	bus_space_write_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0LATCH, 0);

	tm = bus_space_read_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0LOW);
	tm += (bus_space_read_1(clock_sc->sc_iot, clock_sc->sc_ioh,
	    IOMD_T0HIGH) << 8);

	deltatm = timer0_count - tm;
	if (deltatm < 0)
		printf("opps deltatm < 0 tm=%d deltatm=%d\n",
		    tm, deltatm);

	/* Fill in the timeval struct */
	*tvp = time;

	tvp->tv_usec += (deltatm / TICKS_PER_MICROSECOND);

	/* Make sure the micro seconds don't overflow. */
	while (tvp->tv_usec >= 1000000) {
		tvp->tv_usec -= 1000000;
		++tvp->tv_sec;
	}

	/* Make sure the time has advanced. */
	if (tvp->tv_sec == oldtv.tv_sec &&
	    tvp->tv_usec <= oldtv.tv_usec) {
		tvp->tv_usec = oldtv.tv_usec + 1;
		if (tvp->tv_usec >= 1000000) {
			tvp->tv_usec -= 1000000;
			++tvp->tv_sec;
		}
	}

	oldtv = *tvp;
	(void)splx(s);
}

/*
 * Estimated loop for n microseconds
 */

/* Need to re-write this to use the timers */

/* One day soon I will actually do this */

int delaycount = 100;

void
delay(n)
	u_int n;
{
	u_int i;

	if (n == 0) return;
	while (--n > 0) {
		if (cputype == CPU_ID_SA110)	/* XXX - Seriously gross hack */
			for (i = delaycount; --i;);
		else
			for (i = 8; --i;);
	}
}

/* End of iomd_clock.c */