xref: /src/sys/arch/atari/dev/clock.c

/*	$NetBSD: clock.c,v 1.13 1996/10/13 04:10:51 christos Exp $	*/

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1982, 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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 the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 * from: Utah $Hdr: clock.c 1.18 91/01/21$
 *
 *	@(#)clock.c	7.6 (Berkeley) 5/7/91
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <machine/psl.h>
#include <machine/cpu.h>
#include <machine/iomap.h>
#include <machine/mfp.h>
#include <atari/dev/clockreg.h>

#if defined(GPROF) && defined(PROFTIMER)
#include <machine/profile.h>
#endif

/*
 * The MFP clock runs at 2457600Hz. We use a {system,stat,prof}clock divider
 * of 200. Therefore the timer runs at an effective rate of:
 * 2457600/200 = 12288Hz.
 */
#define CLOCK_HZ	12288

/*
 * Machine-dependent clock routines.
 *
 * Inittodr initializes the time of day hardware which provides
 * date functions.
 *
 * Resettodr restores the time of day hardware after a time change.
 */

int	clockmatch __P((struct device *, void *, void *));
void	clockattach __P((struct device *, struct device *, void *));

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

struct cfdriver clock_cd = {
	NULL, "clock", DV_DULL, NULL, 0
};

void statintr __P((struct clockframe *));

static u_long	gettod __P((void));
static int	settod __P((u_long));

static int	divisor;	/* Systemclock divisor	*/

/*
 * Statistics and profile clock intervals and variances. Variance must
 * be a power of 2. Since this gives us an even number, not an odd number,
 * we discard one case and compensate. That is, a variance of 64 would
 * give us offsets in [0..63]. Instead, we take offsets in [1..63].
 * This is symetric around the point 32, or statvar/2, and thus averages
 * to that value (assuming uniform random numbers).
 */
#ifdef STATCLOCK
static int	statvar = 32;	/* {stat,prof}clock variance		*/
static int	statmin;	/* statclock divisor - variance/2	*/
static int	profmin;	/* profclock divisor - variance/2	*/
static int	clk2min;	/* current, from above choises		*/
#endif

int
clockmatch(pdp, match, auxp)
struct device *pdp;
void *match, *auxp;
{
	if(!strcmp("clock", auxp))
		return(1);
	return(0);
}

/*
 * Start the real-time clock.
 */
void clockattach(pdp, dp, auxp)
struct device	*pdp, *dp;
void			*auxp;
{
	/*
	 * Initialize Timer-A in the ST-MFP. We use a divisor of 200.
	 * The MFP clock runs at 2457600Hz. Therefore the timer runs
	 * at an effective rate of: 2457600/200 = 12288Hz. The
	 * following expression works for 48, 64 or 96 hz.
	 */
	divisor       = CLOCK_HZ/hz;
	MFP->mf_tacr  = 0;		/* Stop timer			*/
	MFP->mf_iera &= ~IA_TIMA;	/* Disable timer interrupts	*/
	MFP->mf_tadr  = divisor;	/* Set divisor			*/

	if (hz != 48 && hz != 64 && hz != 96) { /* XXX */
		printf (": illegal value %d for systemclock, reset to %d\n\t",
								hz, 64);
		hz = 64;
	}
	printf(": system hz %d timer-A divisor 200/%d\n", hz, divisor);

#ifdef STATCLOCK
	if ((stathz == 0) || (stathz > hz) || (CLOCK_HZ % stathz))
		stathz = hz;
	if ((profhz == 0) || (profhz > (hz << 1)) || (CLOCK_HZ % profhz))
		profhz = hz << 1;

	MFP->mf_tcdcr &= 0x7;			/* Stop timer		*/
	MFP->mf_ierb  &= ~IB_TIMC;		/* Disable timer inter.	*/
	MFP->mf_tcdr   = CLOCK_HZ/stathz;	/* Set divisor		*/

	statmin  = (CLOCK_HZ/stathz) - (statvar >> 1);
	profmin  = (CLOCK_HZ/profhz) - (statvar >> 1);
	clk2min  = statmin;
#endif /* STATCLOCK */

	/*
	 * Initialize Timer-B in the ST-MFP. This timer is used by the 'delay'
	 * function below. This time is setup to be continueously counting from
	 * 255 back to zero at a frequency of 614400Hz.
	 */
	MFP->mf_tbcr  = 0;		/* Stop timer			*/
	MFP->mf_iera &= ~IA_TIMB;	/* Disable timer interrupts	*/
	MFP->mf_tbdr  = 0;
	MFP->mf_tbcr  = T_Q004;	/* Start timer			*/

}

void cpu_initclocks()
{
	MFP->mf_tacr  = T_Q200;		/* Start timer			*/
	MFP->mf_ipra &= ~IA_TIMA;	/* Clear pending interrupts	*/
	MFP->mf_iera |= IA_TIMA;	/* Enable timer interrupts	*/
	MFP->mf_imra |= IA_TIMA;	/*    .....			*/

#ifdef STATCLOCK
	MFP->mf_tcdcr = (MFP->mf_tcdcr & 0x7) | (T_Q200<<4); /* Start	*/
	MFP->mf_iprb &= ~IB_TIMC;	/* Clear pending interrupts	*/
	MFP->mf_ierb |= IB_TIMC;	/* Enable timer interrupts	*/
	MFP->mf_imrb |= IB_TIMC;	/*    .....			*/
#endif /* STATCLOCK */
}

void
setstatclockrate(newhz)
	int newhz;
{
#ifdef STATCLOCK
	if (newhz == stathz)
		clk2min = statmin;
	else clk2min = profmin;
#endif /* STATCLOCK */
}

#ifdef STATCLOCK
void
statintr(frame)
	register struct clockframe *frame;
{
	register int	var, r;

	var = statvar - 1;
	do {
		r = random() & var;
	} while(r == 0);

	/*
	 * Note that we are always lagging behind as the new divisor
	 * value will not be loaded until the next interrupt. This
	 * shouldn't disturb the median frequency (I think ;-) ) as
	 * only the value used when switching frequencies is used
	 * twice. This shouldn't happen very often.
	 */
	MFP->mf_tcdr = clk2min + r;

	statclock(frame);
}
#endif /* STATCLOCK */

/*
 * Returns number of usec since last recorded clock "tick"
 * (i.e. clock interrupt).
 */
long
clkread()
{
	u_int	delta;

	delta = ((divisor - MFP->mf_tadr) * tick) / divisor;
	/*
	 * Account for pending clock interrupts
	 */
	if(MFP->mf_iera & IA_TIMA)
		return(delta + tick);
	return(delta);
}

#define TIMB_FREQ	614400
#define TIMB_LIMIT	256

/*
 * Wait "n" microseconds.
 * Relies on MFP-Timer B counting down from TIMB_LIMIT at TIMB_FREQ Hz.
 * Note: timer had better have been programmed before this is first used!
 */
void delay(n)
int	n;
{
	int	tick, otick;

	/*
	 * Read the counter first, so that the rest of the setup overhead is
	 * counted.
	 */
	otick = MFP->mf_tbdr;

	/*
	 * Calculate ((n * TIMER_FREQ) / 1e6) using explicit assembler code so
	 * we can take advantage of the intermediate 64-bit quantity to prevent
	 * loss of significance.
	 */
	n -= 5;
	if(n < 0)
		return;
	{
	    u_int	temp;

	    __asm __volatile ("mulul %2,%1:%0" : "=d" (n), "=d" (temp)
					       : "d" (TIMB_FREQ));
	    __asm __volatile ("divul %1,%2:%0" : "=d" (n)
					       : "d"(1000000),"d"(temp),"0"(n));
	}

	while(n > 0) {
		tick = MFP->mf_tbdr;
		if(tick > otick)
			n -= TIMB_LIMIT - (tick - otick);
		else n -= otick - tick;
		otick = tick;
	}
}

#ifdef GPROF
/*
 * profclock() is expanded in line in lev6intr() unless profiling kernel.
 * Assumes it is called with clock interrupts blocked.
 */
profclock(pc, ps)
	caddr_t pc;
	int ps;
{
	/*
	 * Came from user mode.
	 * If this process is being profiled record the tick.
	 */
	if (USERMODE(ps)) {
		if (p->p_stats.p_prof.pr_scale)
			addupc(pc, &curproc->p_stats.p_prof, 1);
	}
	/*
	 * Came from kernel (supervisor) mode.
	 * If we are profiling the kernel, record the tick.
	 */
	else if (profiling < 2) {
		register int s = pc - s_lowpc;

		if (s < s_textsize)
			kcount[s / (HISTFRACTION * sizeof (*kcount))]++;
	}
	/*
	 * Kernel profiling was on but has been disabled.
	 * Mark as no longer profiling kernel and if all profiling done,
	 * disable the clock.
	 */
	if (profiling && (profon & PRF_KERNEL)) {
		profon &= ~PRF_KERNEL;
		if (profon == PRF_NONE)
			stopprofclock();
	}
}
#endif

/***********************************************************************
 *                   Real Time Clock support                           *
 ***********************************************************************/

u_int mc146818_read(rtc, regno)
void	*rtc;
u_int	regno;
{
	((struct rtc *)rtc)->rtc_regno = regno;
	return(((struct rtc *)rtc)->rtc_data & 0377);
}

void mc146818_write(rtc, regno, value)
void	*rtc;
u_int	regno, value;
{
	((struct rtc *)rtc)->rtc_regno = regno;
	((struct rtc *)rtc)->rtc_data  = value;
}

/*
 * Initialize the time of day register, based on the time base which is, e.g.
 * from a filesystem.
 */
void
inittodr(base)
time_t base;
{
	u_long timbuf = base;	/* assume no battery clock exists */

	timbuf = gettod();

	if(timbuf < base) {
		printf("WARNING: bad date in battery clock\n");
		timbuf = base;
	}

	/* Battery clock does not store usec's, so forget about it. */
	time.tv_sec  = timbuf;
	time.tv_usec = 0;
}

void
resettodr()
{
	if(settod(time.tv_sec) == 1)
		return;
	printf("Cannot set battery backed clock\n");
}

static	char	dmsize[12] =
{
	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

static	char	ldmsize[12] =
{
	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

static u_long
gettod()
{
	int		i, sps;
	u_long		new_time = 0;
	char		*msize;
	mc_todregs	clkregs;

	sps = splhigh();
	MC146818_GETTOD(RTC, &clkregs);
	splx(sps);

	if(clkregs[MC_SEC] > 59)
		return(0);
	if(clkregs[MC_MIN] > 59)
		return(0);
	if(clkregs[MC_HOUR] > 23)
		return(0);
	if(range_test(clkregs[MC_DOM], 1, 31))
		return(0);
	if (range_test(clkregs[MC_MONTH], 1, 12))
		return(0);
	if(clkregs[MC_YEAR] > (2000 - GEMSTARTOFTIME))
		return(0);
	clkregs[MC_YEAR] += GEMSTARTOFTIME;

	for(i = BSDSTARTOFTIME; i < clkregs[MC_YEAR]; i++) {
		if(is_leap(i))
			new_time += 366;
		else new_time += 365;
	}

	msize = is_leap(clkregs[MC_YEAR]) ? ldmsize : dmsize;
	for(i = 0; i < (clkregs[MC_MONTH] - 1); i++)
		new_time += msize[i];
	new_time += clkregs[MC_DOM] - 1;
	new_time *= SECS_DAY;
	new_time += (clkregs[MC_HOUR] * 3600) + (clkregs[MC_MIN] * 60);
	return(new_time + clkregs[MC_SEC]);
}

static int
settod(newtime)
u_long	newtime;
{
	register long	days, rem, year;
	register char	*ml;
		 int	sps, sec, min, hour, month;
	mc_todregs	clkregs;

	/* Number of days since Jan. 1 'BSDSTARTOFTIME'	*/
	days = newtime / SECS_DAY;
	rem  = newtime % SECS_DAY;

	/*
	 * Calculate sec, min, hour
	 */
	hour = rem / SECS_HOUR;
	rem %= SECS_HOUR;
	min  = rem / 60;
	sec  = rem % 60;

	/*
	 * Figure out the year. Day in year is left in 'days'.
	 */
	year = BSDSTARTOFTIME;
	while(days >= (rem = is_leap(year) ? 366 : 365)) {
		++year;
		days -= rem;
	}

	/*
	 * Determine the month
	 */
	ml = is_leap(year) ? ldmsize : dmsize;
	for(month = 0; days >= ml[month]; ++month)
		days -= ml[month];

	/*
	 * Now that everything is calculated, program the RTC
	 */
	mc146818_write(RTC, MC_REGA, MC_BASE_32_KHz);
	mc146818_write(RTC, MC_REGB, MC_REGB_24HR | MC_REGB_BINARY);
	sps = splhigh();
	MC146818_GETTOD(RTC, &clkregs);
	clkregs[MC_SEC]   = sec;
	clkregs[MC_MIN]   = min;
	clkregs[MC_HOUR]  = hour;
	clkregs[MC_DOM]   = days+1;
	clkregs[MC_MONTH] = month+1;
	clkregs[MC_YEAR]  = year - GEMSTARTOFTIME;
	MC146818_PUTTOD(RTC, &clkregs);
	splx(sps);

	return(1);
}