/*	$NetBSD: clock.c,v 1.50 2019/08/22 12:47:57 rin 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. 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.
 */

/*-
 * Copyright (C) 1993	Allen K. Briggs, Chris P. Caputo,
 *			Michael L. Finch, Bradley A. Grantham, and
 *			Lawrence A. Kesteloot
 * All rights reserved.
 *
 * 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 Alice Group.
 * 4. The names of the Alice Group or any of its members may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE ALICE GROUP ``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 ALICE GROUP 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.50 2019/08/22 12:47:57 rin Exp $");

#include "opt_rtc_offset.h"

#include <sys/param.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/timetc.h>

#include <dev/clock_subr.h>

#include <machine/autoconf.h>
#include <machine/psl.h>
#include <machine/cpu.h>
#include <machine/limits.h>

#if defined(GPROF) && defined(PROFTIMER)
#include <sys/gprof.h>
#endif

#include <mac68k/mac68k/pram.h>
#include <mac68k/mac68k/clockreg.h>
#include <machine/viareg.h>

#ifdef DEBUG
int	clock_debug = 0;
#endif

void	rtclock_intr(void);
static int mac68k_gettime(todr_chip_handle_t, struct timeval *);
static int mac68k_settime(todr_chip_handle_t, struct timeval *);
static u_int via1_t2_get_timecount(struct timecounter *);

#define	DIFF19041970	2082844800
#define	DIFF19701990	630720000
#define	DIFF19702010	1261440000


/*
 * Mac II machine-dependent clock routines.
 */

/*
 * Start the real-time clock; i.e. set timer latches and boot timer.
 *
 * We use VIA1 timer 1.
 */
void
startrtclock(void)
{
/*
 * BARF MF startrt clock is called twice in init_main, configure,
 * the reason why is doced in configure
 */
	/* be certain all clock interrupts are off */
	via_reg(VIA1, vIER) = V1IF_T1 | V1IF_T2;

	/* set timer latch */
	via_reg(VIA1, vACR) |= ACR_T1LATCH;

	/* set VIA timer 1 latch to 60 Hz (100 Hz) */
	via_reg(VIA1, vT1L) = CLK_INTL;
	via_reg(VIA1, vT1LH) = CLK_INTH;

	/* set VIA timer 1 counter started for 60(100) Hz */
	via_reg(VIA1, vT1C) = CLK_INTL;
	via_reg(VIA1, vT1CH) = CLK_INTH;

	/*
	 * Set & start VIA1 timer 2 free-running for timecounter support.
	 * Since reading the LSB of the counter clears any pending
	 * interrupt, timer 1 is less suitable as a timecounter.
	 */
	via_reg(VIA1, vT2C) = 0x0ff;
	via_reg(VIA1, vT2CH) = 0x0ff;
}

void
enablertclock(void)
{
	/* clear then enable clock interrupt. */
	via_reg(VIA1, vIFR) |= V1IF_T1;
	via_reg(VIA1, vIER) = 0x80 | V1IF_T1;
}

void
cpu_initclocks(void)
{
	static struct todr_chip_handle todr = {
		.todr_settime = mac68k_settime,
		.todr_gettime = mac68k_gettime,
	};
	static struct timecounter via1_t2_timecounter = {
		.tc_get_timecount = via1_t2_get_timecount,
		.tc_poll_pps	  = 0,
		.tc_counter_mask  = 0x0ffffu,
		.tc_frequency	  = CLK_FREQ,
		.tc_name	  = "VIA1 T2",
		.tc_quality	  = 100,
		.tc_priv	  = NULL,
		.tc_next	  = NULL
	};
	
	enablertclock();
	todr_attach(&todr);
	tc_init(&via1_t2_timecounter);
}

void
setstatclockrate(int rateinhz)
{
}

void
disablertclock(void)
{
	/* disable clock interrupt */
	via_reg(VIA1, vIER) = V1IF_T1;
}

static u_int
via1_t2_get_timecount(struct timecounter *tc)
{
	uint8_t high, high2, low;
	int s;

	/* Guard HW timer access */
	s = splhigh();
	
	high = via_reg(VIA1, vT2CH);
	low = via_reg(VIA1, vT2C);

	high2 = via_reg(VIA1, vT2CH);

	/*
	 * If we find that the MSB has just been incremented, read
	 * the LSB again, to avoid a race that could leave us with a new
	 * MSB and an old LSB value.
	 * With timecounters, the difference is quite spectacular.
	 *
	 * is added that to port-amiga ten years ago. Thanks!
	 */
	if (high != high2) {
		low = via_reg(VIA1, vT2C);
		high = high2;
	}
	
	splx(s);
	
	return 0x0ffff - ((high << 8) | low);
}

#ifdef PROFTIMER
/*
 * Here, we have implemented code that causes VIA2's timer to count
 * the profiling clock.  Following the HP300's lead, this reduces
 * the impact on other tasks, since locore turns off the profiling clock
 * on context switches.  If need be, the profiling clock's resolution can
 * be cranked higher than the real-time clock's resolution, to prevent
 * aliasing and allow higher accuracy.
 */
int     profint = PRF_INTERVAL;	/* Clock ticks between interrupts */
int     profinthigh;
int     profintlow;
int     profscale = 0;		/* Scale factor from sys clock to prof clock */
char    profon = 0;		/* Is profiling clock on? */

/* profon values - do not change, locore.s assumes these values */
#define	PRF_NONE	0x00
#define	PRF_USER	0x01
#define	PRF_KERNEL	0x80

void
initprofclock(void)
{
	/* profile interval must be even divisor of system clock interval */
	if (profint > CLK_INTERVAL)
		profint = CLK_INTERVAL;
	else
		if (CLK_INTERVAL % profint != 0)
			/* try to intelligently fix clock interval */
			profint = CLK_INTERVAL / (CLK_INTERVAL / profint);

	profscale = CLK_INTERVAL / profint;

	profinthigh = profint >> 8;
	profintlow = profint & 0xff;
}

void
startprofclock(void)
{
	via_reg(VIA2, vT1L) = (profint - 1) & 0xff;
	via_reg(VIA2, vT1LH) = (profint - 1) >> 8;
	via_reg(VIA2, vACR) |= ACR_T1LATCH;
	via_reg(VIA2, vT1C) = (profint - 1) & 0xff;
	via_reg(VIA2, vT1CH) = (profint - 1) >> 8;
}

void
stopprofclock(void)
{
	via_reg(VIA2, vT1L) = 0;
	via_reg(VIA2, vT1LH) = 0;
	via_reg(VIA2, vT1C) = 0;
	via_reg(VIA2, vT1CH) = 0;
}

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

static u_long	ugmt_2_pramt(u_long);
static u_long	pramt_2_ugmt(u_long);

/*
 * Convert GMT to Mac PRAM time, using rtc_offset
 * GMT bias adjustment is done elsewhere.
 */
static u_long
ugmt_2_pramt(u_long t)
{
	/* don't know how to open a file properly. */
	/* assume compiled timezone is correct. */

	return (t = t + DIFF19041970);
}

/*
 * Convert a Mac PRAM time value to GMT, using rtc_offset
 * GMT bias adjustment is done elsewhere.
 */
static u_long
pramt_2_ugmt(u_long t)
{
	return (t = t - DIFF19041970);
}

/*
 * Time from the booter.
 */
u_long	macos_boottime;

/*
 * Bias in minutes east from GMT (also from booter).
 */
long	macos_gmtbias;

/*
 * Flag for whether or not we can trust the PRAM.  If we don't
 * trust it, we don't write to it, and we take the MacOS value
 * that is passed from the booter (which will only be a second
 * or two off by now).
 */
int	mac68k_trust_pram = 1;

/*
 * Set global GMT time register, using a file system time base for comparison
 * and sanity checking.
 */
int
mac68k_gettime(todr_chip_handle_t tch, struct timeval *tvp)
{
	u_long timbuf;

	timbuf = pramt_2_ugmt(pram_readtime());
	if ((timbuf - macos_boottime) > 10 * 60) {
#if DIAGNOSTIC
		printf(
		    "PRAM time does not appear to have been read correctly.\n");
		printf("PRAM: 0x%lx, macos_boottime: 0x%lx.\n",
		    timbuf, macos_boottime);
#endif
		timbuf = macos_boottime;
		mac68k_trust_pram = 0;
	}
	tvp->tv_sec = timbuf;
#if !defined(RTC_OFFSET) || RTC_OFFSET == 0
	/*
	 * Adjust GTM bias unless RTC_OFFSET is set explicitly.
	 */
	tvp->tv_sec -= macos_gmtbias * 60;
#endif
	tvp->tv_usec = 0;
	return 0;
}

int
mac68k_settime(todr_chip_handle_t tch, struct timeval *tvp)
{
	if (mac68k_trust_pram)
		/*
		 * GMT bias is passed in from the Booter.
		 * To get *our* time, add GMTBIAS to GMT.
		 * (gmtbias is in minutes, multiply by 60).
		 */
		pram_settime(ugmt_2_pramt(tvp->tv_sec + macos_gmtbias * 60));
#ifdef DEBUG
	else if (clock_debug)
		printf("NetBSD/mac68k does not trust itself to try and write "
		    "to the PRAM on this system.\n");
#endif
	return 0;
}

/*
 * The Macintosh timers decrement once every 1.2766 microseconds.
 * MGFH2, p. 180
 */
#define	CLK_RATE	12766

#define	DELAY_CALIBRATE	(0xffffff << 7)	/* Large value for calibration */

u_int		delay_factor = DELAY_CALIBRATE;
volatile int	delay_flag = 1;

int		_delay(u_int);
static void	delay_timer1_irq(void *);

static void
delay_timer1_irq(void *dummy)
{
	delay_flag = 0;
}

/*
 * Calibrate delay_factor with VIA1 timer T1.
 */
void
mac68k_calibrate_delay(void)
{
	u_int sum, n;

	(void)spl0();

	/* Disable VIA1 timer 1 interrupts and set up service routine */
	via_reg(VIA1, vIER) = V1IF_T1;
	via1_register_irq(VIA1_T1, delay_timer1_irq, NULL);

	/* Set the timer for one-shot mode, then clear and enable interrupts */
	via_reg(VIA1, vACR) &= ~ACR_T1LATCH;
	via_reg(VIA1, vIFR) = V1IF_T1;	/* (this is needed for IIsi) */
	via_reg(VIA1, vIER) = 0x80 | V1IF_T1;

#ifdef DEBUG
	if (clock_debug)
		printf("mac68k_calibrate_delay(): entering timing loop\n");
#endif

	for (sum = 0, n = 8; n > 0; n--) {
		delay_flag = 1;
		via_reg(VIA1, vT1C) = 0;	/* 1024 clock ticks */
		via_reg(VIA1, vT1CH) = 4;	/* (approx 1.3 msec) */
		sum += ((delay_factor >> 7) - _delay(1));
	}

	/* Disable timer interrupts and reset service routine */
	via_reg(VIA1, vIER) = V1IF_T1;
	via1_register_irq(VIA1_T1, (void (*)(void *))rtclock_intr, NULL);

	/*
	 * If this weren't integer math, the following would look
	 * a lot prettier.  It should really be something like
	 * this:
	 *	delay_factor = ((sum / 8) / (1024 * 1.2766)) * 128;
	 * That is, average the sum, divide by the number of usec,
	 * and multiply by a scale factor of 128.
	 *
	 * We can accomplish the same thing by simplifying and using
	 * shifts, being careful to avoid as much loss of precision
	 * as possible.  (If the sum exceeds UINT_MAX/10000, we need
	 * to rearrange the calculation slightly to do this.)
	 */
	if (sum > (UINT_MAX / 10000))	/* This is a _fast_ machine! */
		delay_factor = (((sum >> 3) * 10000) / CLK_RATE) >> 3;
	else
		delay_factor = (((sum * 10000) >> 3) / CLK_RATE) >> 3;

	/* Reset the delay_flag for normal use */
	delay_flag = 1;

#ifdef DEBUG
	if (clock_debug)
		printf("mac68k_calibrate_delay(): delay_factor calibrated\n");
#endif

	(void)splhigh();
}
